FORMALDEHYDE-FREE PRINTING INK FOR PRINTING ONTO FABRICS

Abstract

A discharge printing agent contains a sulfinic acid compound, a thickening polymer having carboxylic acid groups —COOH or carboxylate groups —COO— attached to the polymeric backbone, an odour control agent, and water. The discharge printing agent has a viscosity of 2,500-150,000 mPa.Math.s. A method can be used for preparing the discharge printing agent, and a precursor composition of the discharge printing agent can be used in the method. A discharge printing process using the discharge printing agent can produce a dyed fabric having a pattern.

Claims

1: A discharge printing agent, comprising: (a) a sulfinic acid compound of formula (I)
MO—S(═O)—C(R.sup.1)(R.sup.2)(R.sup.3)  (I), or a salt thereof, wherein R.sup.1 is selected from the group consisting of H and NR.sup.4R.sup.5; R.sup.2 is selected from the group consisting of H, OH, alkyl, alkenyl, cycloalkyl, and aryl, wherein the alkyl, alkenyl, cycloalkyl, and aryl group are unsubstituted or substituted with 1, 2, or 3 substituents which are independently selected from the group consisting of an alkyl having 1-6 carbon atoms, OH, an alkoxy having 1-6 carbon atoms, halogen, and CF.sub.3; and R.sup.3 is COOM, SO.sub.3M, COR.sup.4, CONR.sup.4R.sup.5, or COOR.sub.4; each M is independently selected from the group consisting of H, N(R.sup.4).sub.4.sup.+, and a monovalent metal ion or divalent metal ion of groups Ia, IIa, IIb, Iva, or VIIIb of the Periodic Table of the Elements; wherein each R.sup.4 and R.sup.5 is independently selected from the group consisting of H and an alkyl group having 1-6 carbon atoms: (b) a thickener comprising a polymer having carboxylic acid groups —COOH or carboxylate groups —COO— attached to a polymeric backbone; (c) an odour control agent, and (d) water, wherein the discharge printing agent has a viscosity of 2500-150,000 mPa.Math.s.

2: The discharge printing agent according to claim 1, wherein M is independently selected from the group consisting of H, NH.sub.4.sup.+, Li.sup.+, Na.sup.+, and K.sup.+, and/or R.sup.1 is H, R.sup.2 is OH, and R.sup.3 is COOM.

3: The discharge printing agent according to claim 1, wherein the thickener comprises a polymer having repeating units derived from (i) a carboxylic acid having at least one carboxylic acid group, 3-12 carbon atoms, and at least one olefinic carbon-carbon double bond, of which one olefinic carbon-carbon double bond is in α,β-position to at least one carboxyl group and/or an olefinic carbon-carbon double bond formed between two carbon atoms of which one is not linked to a further carbon atom, and (ii) a carboxylic acid ester having 4-42 carbon atoms and at least one olefinic carbon-carbon double bond, of which one olefinic carbon-carbon double bond is in α,β-position to the carboxyl group and/or an olefinic carbon-carbon double bond formed between two carbon atoms of which one is not linked to a further carbon atom, by polymerization of said olefinic carbon-carbon double bond in α,β-position to one carboxyl group and/or said olefinic carbon-carbon double bond formed between two carbon atoms of which one is not linked to a further carbon atom.

4: The discharge printing agent according to claim 1, wherein the odour control agent is an organic compound having at least one functional group selected from the aroup consisting of an isocyanate group (—N═C═O), an isocyanate precursor group, and a carboxylic acid hydrazide group, or a combination of the organic compounds.

5: The discharge printing agent according to claim 4, wherein the odour control agent has at least one of the isocyanate precursor group, wherein said isocyanate precursor group is a blocked isocyanate group.

6: The discharge printing agent according to claim 4, wherein the odour control agent is a carboxylic acid hydrazide having 1-4 hydrazide groups in its molecular structure.

7: The discharge printing agent according to claim 1, further comprising a colouring agent.

8: A precursor composition for the discharge printing agent as defined in claim 1, said precursor composition comprising; (a) the sulfinic acid compound of formula (I) as defined in claim 1, and at least one of (b) 2M thickener as defined in claim 1, and (c) the odour control agent as defined in claim 1.

9: The precursor composition according to claim 8, wherein the precursor composition comprises said thickener in an amount such that a viscosity of 2,500-150,000 mPa s results after the precursor composition is dispersed in water in such an amount that said sulfinic acid compound of formula (I) represents 0.5-15% by weight relative to a total weight of the precursor composition and the water.

10: A method of preparing the discharge printing agent as defined in claim 1, said method comprising: blending (a) said sulfinic acid compound of formula (I) as defined in claim 1, (b) the thickener as defined in claim 1, (c) the odour control agent as defined in claim 1, and (d) water.

11: The method of preparing the discharge printing agent according to claim 10, wherein (a) said sulfinic acid compound of formula (I), and at least one of (b) said thickener, and (c) said odour control agent are provided in a form of a precursor composition.

12: A discharge printing process, comprising: (A) applying the discharge printing agent as defined in claim 1 to a fabric dyed with a dischargeable dye in order to form a pattern of said discharge printing agent on said dyed fabric, to give a dyed fabric comprising an undeveloped pattern; (B) exposing the undeveloped pattern on the dyed fabric to a temperature of 100° C. or more at a pressure that is equal to or higher than a pressure of the surrounding atmosphere, to form a developed pattern on said dyed fabric; wherein the discharge printing process is carried out in a sequence of (A) to (B), and wherein further steps can optionally be present between (A) and (B).

13: The discharge printing process according to claim 12, wherein said dischargeable dye is a dye containing at least one of an azo group, an anthraquinone substructure, a phthalocyanine substructure, a formazane substructure, and a dioxazine substructure.

14: The discharge printing process according to claim 12, wherein the undeveloped pattern on the dyed fabric is exposed in (B) to a temperature of 200° C. or less, and/or (B) is carried out for a period of 1-6 minutes.

15: A dyed fabric, comprising; a pattern obtainable by the discharge printing process as defined in claim 12.

16: The discharge printing agent according to claim 5, wherein the blocked isocyanate group is selected from the group consisting of an allophanate group, a uretdione group, and an isocyanurate group, or wherein the blocked isocyanate group is a product obtained from an addition reaction between an isocyanate group and a functional group selected from the group consisting of a primary, secondary, or tertiary alcohol group; a secondary amine group; an oxime group; a lactam group; a phenolic hydroxyl group; an N-alkylamide group; an imide group; and a carbon atom bonded to an acidic hydrogen atom in a C—H acidic compound.

17: The discharge printing agent according to claim 5, wherein the blocked isocyanate group is a product obtained from an addition reaction between an isocyanate group and a compound selected from the group consisting of 3,5-dimethylpyrazol and 2-butanonoxime.

18: The discharge printing agent according to claim 6, wherein the carboxylic acid hydrazide is a hydrazide of an aliphatic monocarboxylic acid having 2-12 carbon atoms or a dihydrazide of an aliphatic dicarboxylic acid having 2-12 carbon atoms.

19: The discharge printing agent according to claim 7, wherein the colouring agent is a pigment or a dyestuff which does not contain an azo group, an anthraquinone substructure, a phthalocyanine substructure, a formazane substructure, or a dioxazine substructure.

20: The discharge printing process according to claim 14, wherein the temperature in (B) is 160° C. or less.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0031] The present invention in particular encompasses the following embodiments. [0032] [1.1] Discharge printing agent comprising [0033] (a) a sulfinic acid compound of formula (I)

MO—S(═O)—C(R.sup.1)(R.sup.2)(R.sup.3)  (I) [0034] or a salt thereof, wherein [0035] R.sup.1 is selected from the group consisting of H and NR.sup.4R.sup.5; [0036] R.sup.2 is selected from the group consisting of H, OH, alkyl, alkenyl, cycloalkyl and aryl, [0037] wherein the alkyl, alkenyl, cycloalkyl, and aryl group are unsubstituted or substituted with 1, 2 or 3 substituents which are independently selected from alkyl having 1-6 carbon atoms, OH, alkoxy having 1-6 carbon atoms, halogen and CF.sub.3; and [0038] R.sup.3 is COOM, SO.sub.3M, COR.sup.4, CONR.sup.4R.sup.5 or COOR.sub.4; [0039] each M is independently selected from the group consisting of H, N(R.sub.4).sub.4.sup.+, a monovalent metal ion or divalent metal ion of the groups Ia, IIa, IIb, IVa or VIIIb of the Periodic Table of the Elements; [0040] wherein each R.sup.4 and R.sup.5 is independently selected from the group consisting of H or an alkyl group having 1-6 carbon atoms; [0041] (b) a thickener comprising a polymer having carboxylic acid groups —COOH or carboxylate groups —COO— attached to the polymeric backbone; [0042] (c) an odour control agent, and [0043] (d) water, [0044] wherein the discharge printing agent has a viscosity of 2500-150000 mPa.Math.s. [0045] [1.2] Discharge printing agent as defined under item [1.1], wherein the discharge printing agent has a viscosity of 3000-15000 mPa.Math.s. [0046] [1.3] Discharge printing agent as defined under item [1.1], wherein the discharge printing agent has a viscosity of 4000-12000 mPa.Math.s. [0047] [1.4] Discharge printing agent as defined under item [1.1], wherein the discharge printing agent has a viscosity of 25000-50000 mPa.Math.s. [0048] [1.5] Discharge printing agent as defined under item [1.1], wherein the discharge printing agent has a viscosity of 25000-45000 mPa.Math.s. [0049] [1.6] Discharge printing agent as defined under any one of items [1.1]-[1.5], wherein the viscosity is measured using a Brookfield Viscometer DV-II at 20° C. [0050] [1.7] Discharge printing agent as defined under any one of items [1.1]-[1.6], wherein in formula (I) M is selected from the group consisting of H, ammonium ions, alkali metal ions, alkaline earth metal ions, and Zn.sup.2+. [0051] [1.8] Discharge printing agent as defined under item [1.7], wherein in formula (I) M is selected from the group consisting of H, N(R4).sub.4.sup.+, Li.sup.+, Na.sup.+, K.sup.+, Mg.sup.2+, and Ca.sup.2+. [0052] [1.9] Discharge printing agent as defined under item [1.7], wherein in formula (I) [0053] R.sup.1 is H, [0054] R.sup.2 is OH, and [0055] R.sup.3 is COOM, [0056] wherein each M is independently selected from the group consisting of H, NH.sub.4.sup.+, Li.sup.+, Na.sup.+, and K.sup.+. [0057] [1.10] Discharge printing agent as defined under item [1.7], wherein in formula (I) [0058] R.sup.1 is H, [0059] R.sup.2 is OH, and [0060] R.sup.3 is COOM, [0061] wherein each M is independently selected from the group consisting of H and Na.sup.+. [0062] [1.11] Discharge printing agent as defined under any one of items [1.1]-[1.10], wherein the thickener comprises a polymer having repeating units derived from [0063] (i) a carboxylic acid having at least one carboxylic acid group, 3-12 carbon atoms, and at least one olefinic carbon-carbon double bond, of which one olefinic carbon-carbon double bond is in α,β-position to at least one carboxyl group and/or an olefinic carbon-carbon double bond formed between two carbon atoms of which one is not linked to a further carbon atom, [0064] (ii) a carboxylic acid ester having 4-42 carbon atoms and at least one olefinic carbon-carbon double bond, of which one olefinic carbon-carbon double bond is in α,β-position to the carboxyl group and/or an olefinic carbon-carbon double bond formed between two carbon atoms of which one is not linked to a further carbon atom, [0065] by polymerization of said olefinic carbon-carbon double bond in α,β-position to one carboxyl group and/or said olefinic carbon-carbon double bond formed between two carbon atoms of which one is not linked to a further carbon atom. [0066] [1.12] Discharge printing agent as defined under item [1.11], wherein the thickener comprises a polymer furthermore having repeating units derived from a crosslinking monomer (iii) containing at least two olefinic carbon-carbon double bonds, each of which is formed between two carbon atoms of which one is not linked to a further carbon atom. [0067] [1.13] Discharge printing agent as defined under item [1.11] or [1.12], wherein the carboxylic acid (i) has one, two or three carboxylic acid groups. [0068] [1.14] Discharge printing agent as defined under item [1.11] or [1.12], wherein the carboxylic acid (i) has three carboxylic acid groups. [0069] [1.15] Discharge printing agent as defined under item [1.11] or [1.12], wherein the carboxylic acid (i) has two carboxylic acid groups. [0070] [1.16] Discharge printing agent as defined under item [1.11] or [1.12], wherein the carboxylic acid (i) has one carboxylic acid group. [0071] [1.17] Discharge printing agent as defined under any one of items [1.11]-[1.16], wherein the carboxylic acid (i) has one olefinic carbon-carbon double in α,β-position to a carboxyl group. [0072] [1.18] Discharge printing agent as defined under any one of items [1.11]-[1.17], wherein the carboxylic acid (i) has one olefinic carbon-carbon double formed between two carbon atoms of which one is not linked to a further carbon atom. [0073] [1.19] Discharge printing agent as defined under item [1.18], wherein the carboxylic acid (i) has one olefinic carbon-carbon double formed between two carbon atoms of which one is a methylene group. [0074] [1.20] Discharge printing agent as defined under any one of items [1.11]-[1.19], wherein the carboxylic acid (i) has 3-6 carbon atoms. [0075] [1.21] Discharge printing agent as defined under any one of items [1.11]-[1.13], wherein the carboxylic acid (i) is selected from the group consisting of acrylic acid, methacrylic acid, ethacrylic acid, α-chloro-acrylic acid, α-cyano acrylic acid, crotonic acid, α-phenyl acrylic acid, β-acryloxy propionic acid, sorbic acid, α-chloro sorbic acid, angelic acid, cinnamic acid, p-chloro cinnamic acid, β-styrylacrylic acid, itaconic acid, citraconic acid, mesaconic acid, glutaconic acid, aconitic acid, maleic acid, fumaric acid, tricarboxy ethylene, and combinations of these. [0076] [1.22] Discharge printing agent as defined under any one of items [1.11]-[1.13], wherein the carboxylic acid (i) is selected from the group consisting of acrylic acid, methacrylic acid, ethacrylic acid, α-chloro-acrylic acid, α-cyano acrylic acid, crotonic acid, β-acryloxy propionic acid, sorbic acid, α-chloro sorbic acid, angelic acid, itaconic acid, citraconic acid, mesaconic acid, glutaconic acid, aconitic acid, maleic acid, fumaric acid, tricarboxy ethylene, and combinations of these. [0077] [1.23] Discharge printing agent as defined under any one of items [1.11]-[1.13], wherein the carboxylic acid (i) is selected from the group consisting of acrylic acid, methacrylic acid, ethacrylic acid, α-chloro-acrylic acid, α-cyano acrylic acid, β-acryloxy propionic acid, and combinations of these. [0078] [1.24] Discharge printing agent as defined under any one of items [1.11]-[1.13], wherein the carboxylic acid (i) is selected from the group consisting of acrylic acid, methacrylic acid, β-acryloxy propionic acid, and combinations of these. [0079] [1.25] Discharge printing agent as defined under any one of items [1.11]-[1.24], wherein the carboxylic acid ester (ii) is an ester of formula

R.sup.6—COO—R.sup.7, [0080] wherein [0081] R.sup.6 represents a moiety having 2-11 carbon atoms and at least one olefinic carbon-carbon double bond, of which one olefinic carbon-carbon double bond is in α,β-position to the substructure represented by —COO— and/or an olefinic carbon-carbon double bond formed between two carbon atoms of which one is not linked to a further carbon atom, and [0082] R.sup.7 represents an alkyl group having 1-30 carbon atoms. [0083] [1.26] Discharge printing agent as defined under item [1.25], wherein R.sup.6 represents a moiety having one olefinic carbon-carbon double bond, which olefinic carbon-carbon double bond is in α,β-position to the substructure represented by —COO—. [0084] [1.27] Discharge printing agent as defined under item [1.25], wherein R.sup.6 represents a moiety having one olefinic carbon-carbon double bond, which olefinic carbon-carbon double bond is formed between two carbon atoms of which one is not linked to a further carbon atom. [0085] [1.28] Discharge printing agent as defined under item [1.27], wherein R.sup.6 represents a moiety having one olefinic carbon-carbon double bond, which olefinic carbon-carbon double bond is formed between two carbon atoms of which one is a methylene group. [0086] [1.29] Discharge printing agent as defined under any one of items [1.25]-[1.28], wherein R.sup.6 represents a moiety having 2-5 carbon atoms. [0087] [1.30] Discharge printing agent as defined under any one of items [1.25]-[1.28], wherein R.sup.6 represents a moiety having 2, 3 or 4 carbon atoms. [0088] [1.31] Discharge printing agent as defined under any one of items [1.25]-[1.30], wherein R.sup.7 represents an alkyl group having 6-30 carbon atoms. [0089] [1.32] Discharge printing agent as defined under item [1.31], wherein R.sup.7 represents an alkyl group having 10-22 carbon atoms. [0090] [1.33] Discharge printing agent as defined under item [1.31], wherein R.sup.7 represents an alkyl group having 12-18 carbon atoms. [0091] [1.34] Discharge printing agent as defined under any one of items [1.25]-[1.33], wherein the carboxylic acid ester (ii) is an ester of a carboxylic acid selected from the group consisting of acrylic acid, methacrylic acid, ethacrylic acid, α-chloro-acrylic acid, α-cyano acrylic acid, and combinations of these. [0092] [1.35] Discharge printing agent as defined under any one of items [1.25]-[1.33], wherein the carboxylic acid ester (ii) is an ester of a carboxylic acid selected from the group consisting of acrylic acid, methacrylic acid, and combinations of these. [0093] [1.36] Discharge printing agent as defined under any one of items [1.25]-[1.35], wherein the carboxylic acid ester (ii) is an ester of an alcohol selected from the group consisting of n-decanol, iso-decanol, n-dodecanol, n-tetradecanol, n-hexadecanol, n-octadecanol, and combinations of these. [0094] [1.37] Discharge printing agent as defined under any one of items [1.12]-[1.36], wherein the crosslinking monomer (iii) is a hydrocarbon having 4-18 carbon atoms. [0095] [1.38] Discharge printing agent as defined under item [1.37], wherein the crosslinking monomer (iii) is selected from the group consisting of butadiene, isoprene, 1,4-pentadiene, divinylbenzene, divinylnaphthalene, and combinations of these. [0096] [1.39] Discharge printing agent as defined under any one of items [1.12]-[1.36], wherein the crosslinking monomer (iii) has 4-21 carbon atoms and, optionally, 1-11 heteroatoms. [0097] [1.40] Discharge printing agent as defined under item [1.39], wherein the crosslinking monomer (iii) comprises 1 heteroatom. [0098] [1.41] Discharge printing agent as defined under item [1.39], wherein the crosslinking monomer (iii) comprises 2-10 heteroatoms. [0099] [1.42] Discharge printing agent as defined under item [1.39] or item [1.44], wherein the crosslinking monomer (iii) comprises 2-7 heteroatoms. [0100] [1.43] Discharge printing agent as defined under item [1.39], wherein the crosslinking monomer (iii) comprises 2-5 heteroatoms. [0101] [1.44] Discharge printing agent as defined under any one of items [1.39]-[1.43], wherein the crosslinking monomer (iii) is a polyallylether obtained from a polyhydric alcohol containing at least two carbon atoms and having at least two hydroxyl groups by etherification of at least two hydroxyl groups using an allylating agent. [0102] [1.45] Discharge printing agent as defined under any one of items [1.39]-[1.44], wherein the crosslinking monomer (iii) comprises 2-11 oxygen atoms. [0103] [1.46] Discharge printing agent as defined under item [1.45], wherein the crosslinking monomer (iii) comprises 2-10 oxygen atoms. [0104] [1.47] Discharge printing agent as defined under item [1.45], wherein the crosslinking monomer (iii) comprises 2-7 oxygen atoms. [0105] [1.48] Discharge printing agent as defined under item [1.45], wherein the crosslinking monomer (iii) comprises 2-5 oxygen atoms. [0106] [1.49] Discharge printing agent as defined under item [1.44], wherein the polyhydric alcohol has 2, 3, or 4 hydroxyl groups. [0107] [1.50] Discharge printing agent as defined under any one of items [1.44]-[1.49], wherein the crosslinking monomer is a polyallylether having 2, 3, or 4 allyl groups. [0108] [1.51] Discharge printing agent as defined under any one of items [1.44]-[1.50], wherein the polyhydric alcohol has 2, 3, 4, 5 or 6 carbon atoms. [0109] [1.52] Discharge printing agent as defined under any one of items [1.44]-[1.50], wherein the polyhydric alcohol is selected from the group consisting of ethane diol, diethylene glycol, triethylene glycol, glycerine, trimethylol ethane, trimethylol propane, pentaerythritol, 1,6-hexanediol, triethylene glycol, sucrose, and combinations of these. [0110] [1.53] Discharge printing agent as defined under any one of items [1.39] and [1.44]-[1.52], wherein the crosslinking monomer is selected from the group consisting of diallyl ether, dimethallyl ether, ethane diol diallyl ether, glycerine diallyl ether, glycerine triallyl ether, trimethylol ethane diallyl ether, trimethylol ethane triallyl ether, trimethylol propane diallyl ether, trimethylol propane triallyl ether, diethylene glycol diallyl ether, triethylene glycol diallyl ether, pentaerythritol diallyl ether, pentaerythritol triallyl ether, pentaerythritol tetra allyl ether, 1,6-hexanediol diallyl ether, triethylene glycol diallyl ether, sucrose diallyl ether, sucrose triallyl ether, and combinations of these. [0111] [1.54] Discharge printing agent as defined under item [1.12] or item [1.39], wherein the crosslinking monomer (iii) is an ester compound obtained from a polyhydric alcohol containing at least two carbon atoms and having at least two hydroxyl groups by esterification of at least two hydroxyl groups using an acylating agent suitable for forming a group R.sup.8—COO— by reacting with one of said hydroxyl groups, wherein [0112] R.sup.8 has the same meaning as R.sup.6 as defined under any one of items [1.25]-[1.30]. [0113] [1.55] Discharge printing agent as defined under item [1.54], wherein the polyhydric alcohol has 2-12 carbon atoms and, optionally, 1-11 heteroatoms. [0114] [1.56] Discharge printing agent as defined under any one of items [1.54]-[1.55], wherein the polyhydric alcohol comprises 2-11 oxygen atoms. [0115] [1.57] Discharge printing agent as defined under item [1.56], wherein the polyhydric alcohol comprises 2-7 oxygen atoms. [0116] [1.58] Discharge printing agent as defined under item [1.56], wherein the polyhydric alcohol comprises 2-5 oxygen atoms. [0117] [1.59] Discharge printing agent as defined under any one of items [1.54]-[1.58], wherein the polyhydric alcohol has 2, 3, or 4 hydroxyl groups. [0118] [1.60] Discharge printing agent as defined under item [1.54], wherein the polyhydric alcohol is selected from the group consisting of ethane diol, diethylene glycol, triethylene glycol, glycerine, trimethylol ethane, trimethylol propane, pentaerythritol, 1,6-hexanediol, triethylene glycol, sucrose, and combinations of these. [0119] [1.61] Discharge printing agent as defined under any one of items [1.54]-[1.60], wherein the acylating agent suitable for forming an ester of a carboxylic acid is selected from the group consisting of acrylic acid, methacrylic acid, ethacrylic acid, α-chloro-acrylic acid, α-cyano acrylic acid, and combinations of these. [0120] [1.62] Discharge printing agent as defined under any one of items [1.54]-[1.61], wherein the acylating agent suitable for forming an ester of a carboxylic acid is selected from the group consisting of acrylic acid, methacrylic acid, and combinations of these. [0121] [1.63] Discharge printing agent as defined under item [1.12] or item [1.54], wherein the crosslinking monomer (iii) is selected from the group consisting of ethane diol diacryl ester, glycerine diacryl ester, glycerine triacryl ester, trimethylol ethane diacryl ester, trimethylol ethane triacryl ester, trimethylol propane diacryl ester, trimethylol propane triacryl ester, diethylene glycol diacryl ester, triethylene glycol diacryl ester, pentaerythritol diacryl ester, pentaerythritol triacryl ester, pentaerythritol tetraacryl ester, 1,6-hexanediol diacryl ester, triethylene glycol diacryl ester, sucrose diacryl ester, sucrose triacryl ester, ethane diol dimethacryl ester, glycerine dimethacryl ester, glycerine trimethacryl ester, trimethylol ethane dimethacryl ester, trimethylol ethane trimethacryl ester, trimethylol propane dimethacryl ester, trimethylol propane trimethacryl ester, diethylene glycol dimethacryl ester, triethylene glycol dimethacryl ester, pentaerythritol dimethacryl ester, pentaerythritol trimethacryl ester, pentaerythritol tetramethacryl ester, 1,6-hexanediol dimethacryl ester, triethylene glycol dimethacryl ester, sucrose dimethacryl ester, sucrose trimethacryl ester, and combinations of these. [0122] [1.64] Discharge printing agent as defined under item [1.12], wherein the crosslinking monomer (iii) is selected from the group consisting of N-allyl acrylamide, N-allyl methacrylamide, and tetravinyl silane. [0123] [1.65] Discharge printing agent as defined under any one of items [1.11] and [1.13]-[1.64], wherein the polymer is obtained from a monomer mixture comprising [0124] 50-99% by weight of said carboxylic acid (i), and [0125] 1-50% by weight of said carboxylic acid ester (ii). [0126] [1.66] Discharge printing agent as defined under any one of items [1.11] and [1.13]-[1.64], wherein the polymer is obtained from a monomer mixture comprising [0127] 50-95% by weight of said carboxylic acid (i), and [0128] 5-50% by weight of said carboxylic acid ester (ii). [0129] [1.67] Discharge printing agent as defined under any one of items [1.12]-[1.64], wherein the polymer is obtained from a monomer mixture comprising [0130] 60-99% by weight of said carboxylic acid (i), and [0131] 0.5-39.9% by weight of said carboxylic acid ester (ii), and [0132] 0.1-6.0% by weight of said crosslinking monomer (iii). [0133] [1.68] Discharge printing agent as defined under any one of items [1.12]-[1.64], wherein the polymer is obtained from a monomer mixture comprising [0134] 70-99% by weight of said carboxylic acid (i), and [0135] 1-29.9% by weight of said carboxylic acid ester (ii), and [0136] 0.1-1% by weight of said crosslinking monomer (iii). [0137] [1.69] Discharge printing agent as defined under any one of items [1.12]-[1.64], wherein the polymer is obtained from a monomer mixture comprising [0138] 95.9-98.8% by weight of said carboxylic acid (i), and [0139] 1-3.5% by weight of said carboxylic acid ester (ii), and [0140] 0.1-0.6% by weight of said crosslinking monomer (iii). [0141] [1.70] Discharge printing agent as defined under any one of items [1.12]-[1.64], wherein the polymer is obtained from a monomer mixture comprising [0142] 96-97.9% by weight of said carboxylic acid (i), and [0143] 1-3.5% by weight of said carboxylic acid ester (ii), and [0144] 0.1-0.6% by weight of said crosslinking monomer (iii). [0145] [1.71] Discharge printing agent as defined under any one of items [1.12]-[1.64], wherein the polymer is obtained from a monomer mixture comprising [0146] 96-97.9% by weight of said carboxylic acid (i), and [0147] 2-3.5% by weight of said carboxylic acid ester (ii), and [0148] 0.2-0.5% by weight of said crosslinking monomer (iii). [0149] [1.72] Discharge printing agent as defined under any one of items [1.1]-[1.71], wherein the odour control agent is a water-dispersible organic compound having at least one functional group selected from an isocyanate group (—N═C═O), an isocyanate precursor group, and a carboxylic acid hydrazide group, or a combination of such organic compounds. [0150] [1.73] Discharge printing agent as defined under item [1.72], wherein the odour control agent is an organic compound of formula

Q-(NCO).sub.m, [0151] wherein m is a value in the range of 1 to 6, and [0152] Q is an m-valent aliphatic, cycloaliphatic, heterocyclic or aromatic moiety. [0153] [1.74] Discharge printing agent as defined under item[1.73], wherein m in the formula Q-(NCO).sub.m is a value in the range of 2 to 6. [0154] [1.75] Discharge printing agent as defined under item [1.73] or item [1.74], wherein the organic compound of formula Q-(NCO).sub.m is a compound selected from tolylene 2,4-diisocyanate, tolylene 2,6-diisocyanate, a mixture of these isomers (TDI), diphenylmethane 4,4′-diisocyanate, diphenylmethane 2,4′-diisocyanate or diphenylmethane 2,2′-diisocyanate, a mixture of these isomers (MDI), phenylene 1,3-diisocyanate or phenylene 1,4-diisocyanate, 2,3,5,6-tetramethyl-1,4-diisocyanatobenzene, naphthalene 1,5-diisocyanate (NDI), 3,3′-dimethyl-4,4′-diisocyanatodiphenyl (TODD, dianisidine diisocyanate (DADI), ethylene 1,2-diisocyanate, propylene 1,2-diisocyanate, tetramethylene 1,4-diisocyanate, 2-methylpentamethylene 1,5-diisocyanate, hexamethylene 1,6-diisocyanate (HDI), 2,2,4-trimethylhexamethylene 1,6-diisocyanate, 2,4,4-trimethylhexamethylene 1,6-diisocyanate, a mixture of these isomers (TMDI), decamethylene 1,10-diisocyanate, dodecamethylene 1,12-diisocyanate, cyclohexane 1,3-diisocyanate, cyclohexane 1,4-diisocyanate, 1-methyl-2,4-diisocyanatocyclohexane, 1-methyl-2,6-diisocyanatocyclohexane, a mixture of these isomers (HTDI or H6TD1), 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane (isophorone diisocyanate or IPDI), perhydro(diphenylmethane) 2,4′-diisocyanate, perhydro(diphenylmethane) 4,4′-diisocyanate (HMDI or H12M DI), 1,4-diisocyanato-2,2,6-trimethylcyclohexane (TMCDI), 1,3-bis(isocyanatomethyl)cyclohexane, 1,4-bis(isocyanatomethyl)cyclohexane, m-xylylene diisocyanate (m-XDI), p-xylylene diisocyanate (p-XDI), m-tetramethylxylylene 1,3-diisocyanate, m-tetramethylxylylene 1,4-diisocyanate, (m-TMXDI), p-tetramethylxylylene 1,3-diisocyanate, p-tetramethylxylylene 1,4-diisocyanate (p-TMXDI), bis(1-isocyanato-1-methylethyl)naphthalene and mixtures thereof. [0155] [1.76] Discharge printing agent as defined under item [1.74], wherein the organic compound of formula Q-(NCO).sub.m is a compound obtained by reaction of a molar excess amount, relative to the molar amount of isocyanate groups, of any one of the compounds defined under item [1.75] with water or a polyol having a molecular weight of 400 or less. [0156] [1.77] Discharge printing agent as defined under item [1.74], wherein the organic compound of formula Q-(NCO).sub.m is a compound obtained by reaction of a molar excess amount, relative to the molar amount of isocyanate groups, of any one of the compounds defined under item [1.75] with a polyol selected from ethyleneglycol, propyleneglycol, 1,3-butylene glycol, 1,4-butylene glycol, neopentyl glycol, diethylene glycol, triethylene glycol, 2,2,4-trimethyl-1,3-pentane diol, hexamethylene glycol, cyclohexane dimethanol, hydrogenated bisphenol-A, trimethylol propane, trimethylol ethane, 1,2,6-hexane triol, glycerine, sorbitol, pentaerythritol, reaction products of the aforementioned polyols with ethylene oxide, propylene oxide or mixtures thereof which reaction products have a weight-averaged molecular weight of 2000 g/mol or less, and combinations or these. [0157] [1.78] Discharge printing agent as defined under item [1.72], wherein the odour control agent is an organic compounds having at least one isocyanate precursor group, wherein said isocyanate precursor group is a blocked isocyanate group. [0158] [1.79] Discharge printing agent as defined under item [1.78], wherein the blocked isocyanate group is selected from allophanate groups, uretdione groups, isocyanurate groups, or is the product obtained from an addition reaction between an isocyanate group and a functional group selected from a primary, secondary or tertiary alcohol group, a secondary amine group, an oxime group, a lactam group, a phenolic hydroxyl group, an N-alkylamide group, an imide group, the carbon atom bonded to an acidic hydrogen atom in a C—H acidic compound. [0159] [1.80] Discharge printing agent as defined under item [1.78], wherein the blocked isocyanate group is the product obtained from an addition reaction between an isocyanate group and a compound selected from ethanol, isopropanol, tert-butanol, benzyl alcohol, lactic acid C1-C4 alkyl esters, tetrahydrofuryl alcohol, N-hydroxyethyl succinimide, di-n-butylamine, N-methyl-tert-butylamin, diisopropylamine, N-isopropyl-tert-butylamine, N-ethylisopropylamine, 2,2,6,6-tetramethylpiperidine, N-isoproyl-ter-butylamine, N-(tert-butyl)benzylamine, dicyclohexylamine, N-ethylisoproylamine, 4,4,-dimethyloxazolidin, N-isopropyl-tert-butylamine, phenol, o-methylphenol, alkyl esters of salicylic acid, ε-caprolactam, δ-valerolactam, γ-butyrolactam, formaldoxime, acetaldoxime, acetonoxim, 2-butanonoxime, 2-pentanonoxime cyclohexanone oxime, acetophenone oxime, benzophenone oxime, N,N-diethylhydroxylamin, diethyl glyoxime, N-methylacetamide, phthalimide, imidazole, pyrazole, 3-methylpyrazole, 4-nitro-3,5-dimethylpyrazole and 4-bromo-3,5-dimethylpyrazole, 3,5-dimethylpyrazol, triazole, 2-isoproyl-1H-imidazol, malonic acid C1-C4 alkyl esters, diethylmalonate, acetoacetic acid C1-C4 alkyl esters, acetylacetone. [0160] [1.81] Discharge printing agent as defined under item [1.78], wherein the blocked isocyanate group is the product obtained from an addition reaction between an isocyanate group and a compound selected from 3,5-dimethylpyrazol and 2-butanonoxime. [0161] [1.82] Discharge printing agent as defined under item [1.72], wherein the odour control agent is a carboxylic acid hydrazide having 1-4 hydrazide groups in its molecular structure. [0162] [1.83] Discharge printing agent as defined under item [1.82], wherein the carboxylic acid hydrazide is a hydrazide of an aliphatic monocarboxylic acid having 2-12 carbon atoms or a dihydrazide of an aliphatic dicarboxylic acid having 2-12 carbon atoms. [0163] [1.84] Discharge printing agent as defined under item [1.82], wherein the carboxylic acid hydrazide is selected from formhydrazide, acetohydrazide, propionic acid hydrazide, butanoic acid hydrazide, pentanoic acid hydrazide, benzoic acid hydrazide, salicylic acid hydrazide, naphthoic acid hydrazide, oxalic acid dihydrazide, carbodihydrazide, glutaric acid dihydrazide, succinic acid dihydrazide, adipic acid dihydrazide, dodecanedioic acid dihydrazide, fumaric acid dihydrazide, maleic acid dihydrazide, terephthalic acid dihydrazide, azelaic acid dihydrazide, sebacic acid dihydrazide, dodecanoic acid dihydrazide, tartaric acid dihydrazide, malic acid dihydrazide, isophthalic acid dihydrazide, dimer acid dihydrazide, citric acid trihydrazide, 1,2,4-benzenetricarboxylic acid dihydrazide, and a combination of these. [0164] [1.85] Discharge printing agent as defined under item [1.82], wherein the carboxylic acid hydrazide is adipic acid dihydrazide. [0165] [1.86] Discharge printing agent as defined under any one of items [1.1]-[1.85], wherein the sulfinic acid compound of formula (I) is contained in an amount of 0.5-15% by weight relative to the total weight the discharge printing agent. [0166] [1.87] Discharge printing agent as defined under any one of items [1.1]-[1.85], wherein the sulfinic acid compound of formula (I) is contained in an amount of 1.0-12% by weight relative to the total weight the discharge printing agent. [0167] [1.88] Discharge printing agent as defined under any one of items [1.1]-[1.85], wherein the sulfinic acid compound of formula (I) is contained in an amount of 2.0-10% by weight relative to the total weight the discharge printing agent. [0168] [1.89] Discharge printing agent as defined under any one of items [1.1]-[1.88], wherein the thickener (b) is contained in an amount of 0.1-5.0% by weight relative to the total weight the discharge printing agent. [0169] [1.90] Discharge printing agent as defined under any one of items [1.1]-[1.88], wherein the thickener (b) is contained in an amount of 1.0-4.0% by weight relative to the total weight the discharge printing agent. [0170] [1.91] Discharge printing agent as defined under any one of items [1.1]-[1.88], wherein the thickener (b) is contained in an amount of 2.0-3.5% by weight relative to the total weight the discharge printing agent. [0171] [1.92] Discharge printing agent as defined under any one of items [1.1]-[1.91], wherein the odour control agent (c) is contained in an amount of 5-60% by weight relative to the weight of the sulfinic acid compound of formula (I). [0172] [1.93] Discharge printing agent as defined under any one of items [1.1]-[1.91], wherein the odour control agent (c) is contained in an amount of 10-50% by weight relative to the weight of the sulfinic acid compound of formula (I). [0173] [1.94] Discharge printing agent as defined under any one of items [1.1]-[1.91], wherein the odour control agent (c) is contained in an amount of 20-40% by weight relative to the weight of the sulfinic acid compound of formula (I). [0174] [1.95] Discharge printing agent as defined under any one of items [1.1]-[1.94], wherein the discharge printing agent furthermore comprises a colouring agent. [0175] [1.96] Discharge printing agent as defined under item [1.95], wherein the colouring agent is chemically stable in the discharge printing agent. [0176] [1.97] Discharge printing agent as defined under item [1.95] or [1.96], wherein the colouring agent is a pigment or a dyestuff. [0177] [1.98] Discharge printing agent as defined under item [1.95] or [1.96], wherein the colouring agent is a dyestuff that does not contain an azo group, an anthraquinone substructure, a phthalocyanine substructure, a formazane substructure, or a dioxazine substructure. [0178] [1.99] Discharge printing agent as defined under any one of items [1.95]-[1.97], wherein the colouring agent is a pigment, which pigment is a white pigment. [0179] [1.100] Discharge printing agent as defined under item [1.99], wherein the pigment is titanium dioxide. [0180] [1.101] Discharge printing agent as defined under any one of items [1.95]-[1.98], wherein the colouring agent has a colour other than white. [0181] [1.102] Discharge printing agent as defined under any one of items [1.95]-[1.98], wherein the colouring agent has a colour other than white and other than black. [0182] [1.103] Discharge printing agent as defined under item [1.102], wherein the colouring agent has a yellow, red, green, blue, or purple colour. [0183] [1.104] Discharge printing agent as defined under any one of items [1.95]-[1.98], wherein the discharge printing agent comprises a combination of two or more colouring agents. [0184] [1.105] Discharge printing agent as defined under item [1.104], wherein the combination of two or more colouring agents comprises a white pigment. [0185] [1.106] Discharge printing agent as defined under item [1.105], wherein the white pigment is titanium dioxide. [0186] [1.107] Discharge printing agent as defined under any one of items [1.104]-[1.106], wherein the combination of two or more colouring agents comprises a colouring agent having a yellow, red, green, blue, or purple colour. [0187] [1.108] Discharge printing agent as defined under item [1.99] or [1.100], wherein the white pigment is contained in an amount of 1-30% by weight relative to the total weight of the discharge printing agent. [0188] [1.109] Discharge printing agent as defined under item [1.99] or [1.100], wherein the white pigment is contained in an amount of 2-20% by weight relative to the total weight of the discharge printing agent. [0189] [1.110] Discharge printing agent as defined under item [1.99] or [1.100], wherein the white pigment is contained in an amount of 3-15% by weight relative to the total weight of the discharge printing agent. [0190] [1.111] Discharge printing agent as defined under any one of items [1.95]-[1.107], wherein the total amount of colouring agents is 1-10% by weight, relative to the total weight of the discharge printing agent. [0191] [1.112] Discharge printing agent as defined under any one of items [1.95]-[1.107], wherein the total amount of colouring agents is 2-8% by weight, relative to the total weight of the discharge printing agent. [0192] [1.113] Discharge printing agent as defined under any one of items [1.1]-[1.112], wherein the discharge printing agent furthermore comprises one or more of a humectant, a defoamer, a pH regulator, an emulsifier, and a catalyst. [0193] [1.114] Discharge printing agent as defined under item [1.113], wherein the humectant is urea and/or glycerol. [0194] [1.115] Discharge printing agent as defined under item [1.113], wherein the catalyst is a zinc salt of a carboxylic acid or a hydrated form of such a zinc salt. [0195] [1.116] Discharge printing agent as defined under item [1.113], wherein the catalyst is zinc citrate, zinc acetate or a hydrated form of these. [0196] [2.1] Precursor composition for a discharge printing agent as defined under any one of items [1.1]-[1.116], comprising [0197] (a) a sulfinic acid compound of formula (I) as defined under any one of items [1.1] and [1.7]-[1.10], [0198] and at least one of [0199] (b) a thickener as defined under any one of items [1.1] and [1.11]-[1.71]; and [0200] (c) an odour control agent as defined under any one of items [1.1] and [1.72]-[1.85]. [0201] [2.2] Precursor composition as defined under item [2.1], comprising [0202] (b) said thickener; and [0203] (c) said odour control agent. [0204] [2.3] Precursor composition as defined under item [2.1], comprising said sulfinic acid compound of formula (I) and said odour control agent, wherein the odour control agent (c) is contained in an amount of 5-60% by weight relative to the weight of the sulfinic acid compound of formula (I). [0205] [2.4] Precursor composition as defined under item [2.1], comprising said sulfinic acid compound of formula (I) and said odour control agent, wherein the odour control agent (c) is contained in an amount of 10-50% by weight relative to the weight of the sulfinic acid compound of formula (I). [0206] [2.5] Precursor composition as defined under item [2.1], comprising said sulfinic acid compound of formula (I) and said odour control agent, wherein the odour control agent (c) is contained in an amount of 20-40% by weight relative to the weight of the sulfinic acid compound of formula (I). [0207] [2.6] Precursor composition as defined under any one of items [2.1]-[2.5], wherein the thickener is present in an amount such that a viscosity of 2500-150000 mPa.Math.s results after the precursor composition was dispersed in water in such an amount that said sulfinic acid compound of formula (I) represents 0.5-15% by weight relative to total weight of the precursor composition and the water. [0208] [2.7] Precursor composition as defined under any one of items [2.1]-[2.5], wherein the thickener is present in an amount such that a viscosity of 3000-15000 mPa.Math.s results after the precursor composition was dispersed in water in such an amount that said sulfinic acid compound of formula (I) represents 0.5-15% by weight relative to total weight of the precursor composition and the water. [0209] [2.8] Precursor composition as defined under any one of items [2.1]-[2.5], wherein the thickener is present in an amount such that a viscosity of 4000-12000 mPa.Math.s results after the precursor composition was dispersed in water in such an amount that said sulfinic acid compound of formula (I) represents 0.5-15% by weight relative to total weight of the precursor composition and the water. [0210] [2.9] Precursor composition as defined under any one of items [2.1]-[2.5], wherein the thickener is present in an amount such that a viscosity of 25000-50000 mPa.Math.s results after the precursor composition was dispersed in water in such an amount that said sulfinic acid compound of formula (I) represents 0.5-15% by weight relative to total weight of the precursor composition and the water. [0211] [2.10] Precursor composition as defined under any one of items [2.1]-[2.5], wherein the thickener is present in an amount such that a viscosity of 25000-45000 mPa.Math.s results after the precursor composition was dispersed in water in such an amount that said sulfinic acid compound of formula (I) represents 0.5-15% by weight relative to total weight of the precursor composition and the water. [0212] [2.11] Precursor composition as defined under any one of items [2.1]-[2.5], wherein the thickener is present in an amount such that a viscosity of 2500-150000 mPa.Math.s results after the precursor composition was dispersed in water in such an amount that said sulfinic acid compound of formula (I) represents 1.0-12% by weight relative to total weight of the precursor composition and the water. [0213] [2.12] Precursor composition as defined under any one of items [2.1]-[2.5], wherein the thickener is present in an amount such that a viscosity of 3000-15000 mPa.Math.s results after the precursor composition was dispersed in water in such an amount that said sulfinic acid compound of formula (I) represents 1.0-12% by weight relative to total weight of the precursor composition and the water. [0214] [2.13] Precursor composition as defined under any one of items [2.1]-[2.5], wherein the thickener is present in an amount such that a viscosity of 4000-12000 mPa.Math.s results after the precursor composition was dispersed in water in such an amount that said sulfinic acid compound of formula (I) represents 1.0-12% by weight relative to total weight of the precursor composition and the water. [0215] [2.14] Precursor composition as defined under any one of items [2.1]-[2.5], wherein the thickener is present in an amount such that a viscosity of 25000-50000 mPa.Math.s results after the precursor composition was dispersed in water in such an amount that said sulfinic acid compound of formula (I) represents 1.0-12% by weight relative to total weight of the precursor composition and the water. [0216] [2.15] Precursor composition as defined under any one of items [2.1]-[2.5], wherein the thickener is present in an amount such that a viscosity of 25000-45000 mPa.Math.s results after the precursor composition was dispersed in water in such an amount that said sulfinic acid compound of formula (I) represents 1.0-12% by weight relative to total weight of the precursor composition and the water. [0217] [2.16] Precursor composition as defined under any one of items [2.1]-[2.5], wherein the thickener is present in an amount such that a viscosity of 2500-150000 mPa.Math.s results after the precursor composition was dispersed in water in such an amount that said sulfinic acid compound of formula (I) represents 2.0-10% by weight relative to total weight of the precursor composition and the water. [0218] [2.17] Precursor composition as defined under any one of items [2.1]-[2.5], wherein the thickener is present in an amount such that a viscosity of 3000-15000 mPa.Math.s results after the precursor composition was dispersed in water in such an amount that said sulfinic acid compound of formula (I) represents 2.0-10% by weight relative to total weight of the precursor composition and the water. [0219] [2.18] Precursor composition as defined under any one of items [2.1]-[2.5], wherein the thickener is present in an amount such that a viscosity of 4000-12000 mPa.Math.s results after the precursor composition was dispersed in water in such an amount that said sulfinic acid compound of formula (I) represents 2.0-10% by weight relative to total weight of the precursor composition and the water. [0220] [2.19] Precursor composition as defined under any one of items [2.1]-[2.5], wherein the thickener is present in an amount such that a viscosity of 25000-50000 mPa.Math.s results after the precursor composition was dispersed in water in such an amount that said sulfinic acid compound of formula (I) represents 2.0-10% by weight relative to total weight of the precursor composition and the water. [0221] [2.20] Precursor composition as defined under any one of items [2.1]-[2.5], wherein the thickener is present in an amount such that a viscosity of 25000-45000 mPa.Math.s results after the precursor composition was dispersed in water in such an amount that said sulfinic acid compound of formula (I) represents 2.0-10% by weight relative to total weight of the precursor composition and the water. [0222] [2.21] Precursor composition as defined under any one of items [2.6]-[2.20], wherein the viscosity is measured using a Brookfield Viscometer DV-II at 20° C. [0223] [3.1] Method of preparing a discharge printing agent as defined under any one of items [1.1]-[1.116], said method comprising a step of blending [0224] (a) a sulfinic acid compound of formula (I) as defined under any one of items [1.1] and [1.7]-[1.10], [0225] (b) a thickener as defined under any one of items [1.1] and [1.11]-[1.71]; [0226] (c) an odour control agent as defined under any one of items [1.1] and [1.72]-[1.85], and [0227] (d) water, [0228] to give a discharge printing agent having a viscosity of 2500-150000 mPa.Math.s. [0229] [4.1] Discharge printing process comprising the steps of [0230] (A) applying a discharge printing agent as defined under any one of items [1.1]-[1.116] to a fabric dyed with a dischargeable dye in order to form a pattern of said discharge printing agent on said dyed fabric so as to give a dyed fabric comprising an undeveloped pattern; [0231] (B) exposing the undeveloped pattern on the dyed fabric to a temperature of 100° C. or more at a pressure that is equal to or higher than the pressure of the surrounding atmosphere so as to form a developed pattern on said dyed fabric; [0232] wherein the steps are carried out in the sequence (A) to (B) and wherein further steps can optionally be present between these steps (A) and (B). [0233] [4.2] Discharge printing process as defined under item [4.1], wherein said dischargeable dye is a dye containing at least one of an azo group, an anthraquinone substructure, a phthalocyanine substructure, a formazane substructure, and a dioxazine substructure. [0234] [4.3] Discharge printing process as defined under item [4.1], wherein a step (A1) is carried out after said step (A) and before said step (B), which step (A1) is a step of allowing the water from the discharge printing agent present in said undeveloped pattern to evaporate at least partially. [0235] [4.4] Discharge printing process as defined under item [4.1] or [4.3], wherein step (B) comprises exposing the undeveloped pattern on the dyed fabric to at least one of steam, hot air, and infrared irradiation. [0236] [4.5] Discharge printing process as defined under item [4.4], wherein step (B) comprises exposing the undeveloped pattern on the dyed fabric to hot air and infrared irradiation. [0237] [4.6] Discharge printing process as defined under item [4.4] or [4.5], wherein the infrared irradiation is electromagnetic irradiation having a wavelength in the range of 700 nm to 1 mm. [0238] [4.7] Discharge printing process as defined under any one of items [4.4]-[4.6], wherein the undeveloped pattern on the dyed fabric is exposed in step (B) to a temperature of 200° C. or less. [0239] [4.8] Discharge printing process as defined under any one of items [4.4]-[4.6], wherein the undeveloped pattern on the dyed fabric is exposed in step (B) to a temperature of 180° C. or less. [0240] [4.9] Discharge printing process as defined under any one of items [4.4]-[4.6], wherein the undeveloped pattern on the dyed fabric is exposed in step (B) to a temperature of 160° C. or less. [0241] [4.10] Discharge printing process as defined under any one of items [4.1]-[4.9], wherein said step (B) is carried out for a period of 1-6 minutes. [0242] [5.1] Dyed fabric comprising a pattern obtainable by a discharge printing process as defined under any one of items [4.1]-[4.10].

Aspect (1): Discharge Printing Agent

[0243] In a first aspect, the present invention provides a discharge printing agent comprising [0244] (a) a sulfinic acid compound of formula (I)

MO—S(═O)—C(R.sup.1)(R.sup.2)(R.sup.3)  (I) [0245] or a salt thereof, wherein [0246] R.sup.1 is selected from the group consisting of H and NR.sup.4R.sup.5; [0247] R.sup.2 is selected from the group consisting of H, OH, alkyl, alkenyl, cycloalkyl and aryl, wherein the alkyl, alkenyl, cycloalkyl, and aryl group are unsubstituted or substituted with 1, 2 or 3 substituents which are independently selected from alkyl having 1-6 carbon atoms, OH, alkoxy having 1-6 carbon atoms, halogen and CF.sub.3; and [0248] R.sup.3 is COOM, SO.sub.3M, COR.sup.4, CONR.sup.4R.sup.5 or COOR.sub.4; [0249] each M is independently selected from the group consisting of H, N(R.sup.4).sub.4.sup.+, a monovalent metal ion or divalent metal ion of the groups Ia, IIa, IIb, IVa or VIIIb of the Periodic Table of the Elements; [0250] wherein each R.sup.4 and R.sup.5 is independently selected from the group consisting of H or an alkyl group having 1-6 carbon atoms; [0251] (b) a thickener comprising a polymer having carboxylic acid groups —COOH or carboxylate groups —COO— attached to the polymeric backbone; [0252] (c) an odour control agent, and [0253] (d) water, [0254] wherein the discharge printing agent has a viscosity of 2500-150000 mPa.Math.s.

[0255] In preferred embodiments, the components contained in the discharge printing agent are characterized by means of the following features.

[0256] (a) Sulfinic Acid Compound of Formula (I)

[0257] In the sulfinic acid compound of formula (I), M is preferably selected from the group consisting of H, ammonium ions, alkali metal ions, alkaline earth metal ions, and Zn.sup.2+, more preferably rom the group consisting of H, N(R.sup.4).sub.4.sup.+, Li.sup.+, Na.sup.+, K.sup.+, Mg.sup.2+, and Ca.sup.2+. Even more preferably, R.sup.1 is H, R.sup.2 is OH, and R.sup.3 is COOM, wherein M is independently selected from the group consisting of H, NH.sub.4.sup.+, Li.sup.+, Na.sup.+, and K.sup.+. Still more preferably, each M is independently selected from the group consisting of H and Na.sup.+.

[0258] A preferred sulfinic acid compound of formula (I) is commercially available from CHT Germany GmbH (Tübingen, Germany).

[0259] (b) Thickener

[0260] The thickener of the discharge printing agent comprises a polymer having carboxylic acid groups —COOH or carboxylate groups —COO— attached to the polymeric backbone. In preferred embodiments, the thickener comprises a polymer having repeating units derived from [0261] (i) a carboxylic acid having at least one carboxylic acid group, 3-12 carbon atoms, and at least one olefinic carbon-carbon double bond, of which one olefinic carbon-carbon double bond is in α,β-position to at least one carboxyl group and/or an olefinic carbon-carbon double bond formed between two carbon atoms of which one is not linked to a further carbon atom, and [0262] (ii) a carboxylic acid ester having 4-42 carbon atoms and at least one olefinic carbon-carbon double bond, of which one olefinic carbon-carbon double bond is in α,β-position to the carboxyl group and/or an olefinic carbon-carbon double bond formed between two carbon atoms of which one is not linked to a further carbon atom, [0263] by polymerization of said olefinic carbon-carbon double bond in α,β-position to one carboxyl group and/or said olefinic carbon-carbon double bond formed between two carbon atoms of which one is not linked to a further carbon atom.

[0264] It is understood that an olefinic carbon-carbon double bond formed between two carbon atoms of which one is not linked to a further carbon atom is commonly also referred to as a terminal carbon-carbon double bond, i.e. one of said carbon atoms forms a methylene group (═CH.sub.2).

[0265] Preferably, the polymer can furthermore comprises repeating units derived from a crosslinking monomer (iii) containing at least two olefinic carbon-carbon double bonds, each of which is formed between two carbon atoms of which one is not linked to a further carbon atom.

[0266] Said carboxylic acid (i) preferably has one, two or three carboxylic acid groups and one olefinic carbon-carbon double in α,β-position to a carboxyl group. If more than one carboxylic acid group is present in the molecule, the olefinic carbon-carbon double can be in α,β-position to one or more of said carboxyl groups.

[0267] Preferably, the carboxylic acid (i) has 3-6 carbon atoms and, more preferably, is selected from the group consisting of acrylic acid, methacrylic acid, ethacrylic acid, α-chloro-acrylic acid, α-cyano acrylic acid, crotonic acid, α-phenyl acrylic acid, β-acryloxy propionic acid, sorbic acid, α-chloro sorbic acid, angelic acid, cinnamic acid, p-chloro cinnamic acid, β-styrylacrylic acid, itaconic acid, citraconic acid, mesaconic acid, glutaconic acid, aconitic acid, maleic acid, fumaric acid, tricarboxy ethylene, and combinations of these. Of these carboxylic acids, acrylic acid, methacrylic acid, ethacrylic acid, α-chloro-acrylic acid, α-cyano acrylic acid, crotonic acid, β-acryloxy propionic acid, sorbic acid, α-chloro sorbic acid, angelic acid, itaconic acid, citraconic acid, mesaconic acid, glutaconic acid, aconitic acid, maleic acid, fumaric acid, tricarboxy ethylene, and combinations of these are even more preferred. Acrylic acid, methacrylic acid, ethacrylic acid, α-chloro-acrylic acid, α-cyano acrylic acid, β-acryloxy propionic acid are particularly preferred and acrylic acid, methacrylic acid, β-acryloxy propionic acid, and combinations of these are most preferred.

[0268] Said carboxylic acid ester (ii) preferably is an ester of formula

R.sup.6—COO—R.sup.7, wherein [0269] R.sup.6 represents a moiety having 2-11 carbon atoms and at least one olefinic carbon-carbon double bond, of which one olefinic carbon-carbon double bond is in α,β-position to the substructure represented by —COO— and/or an olefinic carbon-carbon double bond formed between two carbon atoms of which one is not linked to a further carbon atom, and R.sup.7 represents an alkyl group having 1-30 carbon atoms.

[0270] Preferably, R.sup.6 represents a moiety having 2-5 carbon atoms, such as a moiety having 2, 3 or 4 carbon atoms. Preferably in a similar manner, R.sup.7 represents an alkyl group having 6-30 carbon atoms, more preferably an alkyl group having 10-22 carbon atoms or even more preferably an alkyl group having 12-18 carbon atoms.

[0271] Thus, the carboxylic acid ester (ii) can be an ester of a carboxylic acid selected from the group consisting of acrylic acid, methacrylic acid, ethacrylic acid, α-chloro-acrylic acid, α-cyano acrylic acid, and combinations of these, preferably an ester of a carboxylic acid selected from the group consisting of acrylic acid, methacrylic acid, and combinations of these. The carboxylic acid ester (ii) can be an ester of an alcohol selected from the group consisting of n-decanol, iso-decanol, n-dodecanol, n-tetradecanol, n-hexadecanol, n-octadecanol, and combinations of these.

[0272] The crosslinking monomer (iii) can be a hydrocarbon having 4-18 carbon atoms, such as a hydrocarbon selected from the group consisting of butadiene, isoprene, 1,4-pentadiene, divinylbenzene, divinylnaphthalene, and combinations of these.

[0273] In alternative embodiments, the crosslinking monomer (iii) has 4-21 carbon atoms and, optionally, 1-11 heteroatoms, such as 1 heteroatom or 2-10 heteroatoms, preferably 2-7 heteroatoms or 2-5 heteroatoms. Thus, wherein the crosslinking monomer (iii) can be a polyallylether obtained from a polyhydric alcohol containing at least two carbon atoms and having at least two hydroxyl groups by etherification of at least two hydroxyl groups using an allylating agent. In these alternative embodiments, the crosslinking monomer (iii) can comprise 2-11 oxygen atoms, such as 2-10 oxygen atoms, 2-7 oxygen atoms, or 2-5 oxygen atoms. Preferably, said polyhydric alcohol has 2, 3, or 4 hydroxyl groups. In these alternative embodiments, the crosslinking monomer can be a polyallylether having 2, 3, or 4 allyl groups. The polyhydric alcohol can have 2, 3, 4, 5 or 6 carbon atoms and can preferably be selected from ethane diol, diethylene glycol, triethylene glycol, glycerine, trimethylol ethane, trimethylol propane, pentaerythritol, 1,6-hexanediol, triethylene glycol, sucrose, and combinations of these.

[0274] Thus, the crosslinking monomer can be a polyallylether selected from diallyl ether, dimethallyl ether, ethane diol diallyl ether, glycerine diallyl ether, glycerine triallyl ether, trimethylol ethane diallyl ether, trimethylol ethane triallyl ether, trimethylol propane diallyl ether, trimethylol propane triallyl ether, diethylene glycol diallyl ether, triethylene glycol diallyl ether, pentaerythritol diallyl ether, pentaerythritol triallyl ether, pentaerythritol tetra allyl ether, 1,6-hexanediol diallyl ether, triethylene glycol diallyl ether, sucrose diallyl ether, sucrose triallyl ether, and combinations of these.

[0275] In further alternative embodiments, the crosslinking monomer (iii) is an ester compound obtained from a polyhydric alcohol containing at least two carbon atoms and having at least two hydroxyl groups by esterification of at least two hydroxyl groups using an acylating agent suitable for forming a group R.sup.8—COO— by reacting with one of said hydroxyl groups, wherein R.sup.8 has the same meaning as R.sup.6 as described in the preceding paragraphs. The polyhydric alcohol has 2-12 carbon atoms and, optionally, 1-11 heteroatoms, such as 2-11 oxygen atoms, 2-7 oxygen atoms, or 2-5 oxygen atoms. For instance, the polyhydric alcohol has 2, 3, or 4 hydroxyl groups. Thus, the polyhydric alcohol can be selected from the group consisting of ethane diol, diethylene glycol, triethylene glycol, glycerine, trimethylol ethane, trimethylol propane, pentaerythritol, 1,6-hexanediol, triethylene glycol, sucrose, and combinations of these. The acylating agent suitable for forming an ester of a carboxylic acid can be selected from the group consisting of acrylic acid, methacrylic acid, ethacrylic acid, α-chloro-acrylic acid, α-cyano acrylic acid, and combinations of these; preferably, the acylating agent suitable for forming an ester of a carboxylic acid is selected from acrylic acid, methacrylic acid, and combinations of these. Thus, the crosslinking monomer (iii) can be selected from ethane diol diacryl ester, glycerine diacryl ester, glycerine triacryl ester, trimethylol ethane diacryl ester, trimethylol ethane triacryl ester, trimethylol propane diacryl ester, trimethylol propane triacryl ester, diethylene glycol diacryl ester, triethylene glycol diacryl ester, pentaerythritol diacryl ester, pentaerythritol triacryl ester, pentaerythritol tetraacryl ester, 1,6-hexanediol diacryl ester, triethylene glycol diacryl ester, sucrose diacryl ester, sucrose triacryl ester, ethane diol dimethacryl ester, glycerine dimethacryl ester, glycerine trimethacryl ester, trimethylol ethane dimethacryl ester, trimethylol ethane trimethacryl ester, trimethylol propane dimethacryl ester, trimethylol propane trimethacryl ester, diethylene glycol dimethacryl ester, triethylene glycol dimethacryl ester, pentaerythritol dimethacryl ester, pentaerythritol trimethacryl ester, pentaerythritol tetramethacryl ester, 1,6-hexanediol dimethacryl ester, triethylene glycol dimethacryl ester, sucrose dimethacryl ester, sucrose trimethacryl ester, and combinations of these.

[0276] In still further alternative embodiments, the crosslinking monomer (iii) can be selected from the group consisting of N-allyl acrylamide, N-allyl methacrylamide, and tetravinyl silane.

[0277] The thickener thus can be a polymer that is obtained from a monomer mixture comprising 50-99% by weight of said carboxylic acid (i), and 1-50% by weight of said carboxylic acid ester (ii). Preferably, the polymer is obtained from a monomer mixture comprising 50-95% by weight of said carboxylic acid (i), and 5-50% by weight of said carboxylic acid ester (ii). When the monomer mixture said crosslinking monomer (iii), the monomer mixture can comprise 60-99% by weight of said carboxylic acid (i), 0.5-39.9% by weight of said carboxylic acid ester (ii), and 0.1-6.0% by weight of said crosslinking monomer (iii). In preferred embodiments, the monomer mixture can comprise 70-99% by weight of said carboxylic acid (i), 1-29.9% by weight of said carboxylic acid ester (ii), and 0.1-1% by weight of said crosslinking monomer (iii). More preferably, the monomer mixture can comprise 95.9-98.8% by weight of said carboxylic acid (i), 1-3.5% by weight of said carboxylic acid ester (ii), and 0.1-0.6% by weight of said crosslinking monomer (iii). Even more preferably, the monomer mixture can comprise 96-97.9% by weight of said carboxylic acid (i), 1-3.5% by weight of said carboxylic acid ester (ii), and 0.1-0.6% by weight of said crosslinking monomer (iii). Still more preferably, the monomer mixture can comprise 96-97.9% by weight of said carboxylic acid (i), 2-3.5% by weight of said carboxylic acid ester (ii), and 0.2-0.5% by weight of said crosslinking monomer (iii).

[0278] Thickeners suitable for being used in the present invention are disclosed in U.S. Pat. Nos. 4,509,949 and 3,915,921, for instance. By using a suitable amount of the thickener, the viscosity of the discharge printing agent is set to a range of 2500-150000 mPa.Math.s, preferably 3000-15000 mPa.Math.s, more preferably 4000-12000. In alternative preferred embodiments, the viscosity can be set to a range of 25000-50000 mPa.Math.s or 25000-45000 mPa.Math.s. The viscosity is measured using a Brookfield Viscometer DV-II at 20° C. according to a method that is commonly known to the skilled person and also described in the examples section hereinbelow.

[0279] A viscosity within these ranges can usually be accomplished when the the thickener (b) is contained in an amount of 0.1-5.0% by weight, preferably 1.0-4.0% by weight, or 2.0-3.5% by weight, relative to the total weight the discharge printing agent.

[0280] (c) Odour Control Agent

[0281] The odour control agent of the discharge printing agent is believed to scavenge products of the discharge reaction, such as products resulting from the action of said sulfinic acid of formula (I). Thus, the development of malodors is prevented. As a result, no step of washing a fabric treated with discharge printing agent of the present invention is required before the fabric can be further processed or even be delivered to a retailing entity or a consumer.

[0282] The odour control agent can be a water-dispersible organic compound having at least one functional group selected from an isocyanate group (—N═C═O), an isocyanate precursor group, and a carboxylic acid hydrazide group, or a combination of such organic compounds.

[0283] In preferred embodiments, the odour control agent is an organic compound of formula

Q-(NCO).sub.m

wherein m is a value in the range of 1 to 6, preferably 2 to 6, and
Q is an m-valent aliphatic, cycloaliphatic, heterocyclic or aromatic moiety.

[0284] For instance, the organic compound of formula Q-(NCO).sub.m is a compound selected from tolylene 2,4-diisocyanate, tolylene 2,6-diisocyanate, a mixture of these isomers (TDI), diphenylmethane 4,4′-diisocyanate, diphenylmethane 2,4′-diisocyanate or diphenylmethane 2,2′-diisocyanate, a mixture of these isomers (MDI), phenylene 1,3-diisocyanate or phenylene 1,4-diisocyanate, 2,3,5,6-tetramethyl-1,4-diisocyanatobenzene, naphthalene 1,5-diisocyanate (NDI), 3,3′-dimethyl-4,4′-diisocyanatodiphenyl (TODD, dianisidine diisocyanate (DADI), ethylene 1,2-diisocyanate, propylene 1,2-diisocyanate, tetramethylene 1,4-diisocyanate, 2-methylpentamethylene 1,5-diisocyanate, hexamethylene 1,6-diisocyanate (HDI), 2,2,4-trimethylhexamethylene 1,6-diisocyanate, 2,4,4-trimethylhexamethylene 1,6-diisocyanate, a mixture of these isomers (TMDI), decamethylene 1,10-diisocyanate, dodecamethylene 1,12-diisocyanate, cyclohexane 1,3-diisocyanate, cyclohexane 1,4-diisocyanate, 1-methyl-2,4-diisocyanatocyclohexane, 1-methyl-2,6-diisocyanatocyclohexane, a mixture of these isomers (HTDI or H6TDI), 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane (isophorone diisocyanate or IPDI), perhydro(diphenylmethane) 2,4′-diisocyanate, perhydro(diphenylmethane) 4,4′-diisocyanate (HMDI or H12MDI), 1,4-diisocyanato-2,2,6-trimethylcyclohexane (TMCDI), 1,3-bis(isocyanatomethyl)cyclohexane, 1,4-bis(isocyanatomethyl)cyclohexane, m-xylylene diisocyanate (m-XDI), p-xylylene diisocyanate (p-XDI), m-tetramethylxylylene 1,3-diisocyanate, m-tetramethylxylylene 1,4-diisocyanate, (m-TMXDI), p-tetramethylxylylene 1,3-diisocyanate, p-tetramethylxylylene 1,4-diisocyanate (p-TMXDI), bis(1-isocyanato-1-methylethyl)naphthalene and mixtures thereof. The organic compound of formula Q-(NCO).sub.m can also be a compound obtained by reaction of a molar excess amount, relative to the molar amount of isocyanate groups, of any one of these aforementioned exemplary compounds with water or a polyol having a molecular weight of 400 or less.

[0285] Thus, the organic compound of formula Q-(NCO).sub.m can be obtained by reaction of a molar excess amount, relative to the molar amount of isocyanate groups, of any one of these aforementioned exemplary compounds with a polyol selected from ethyleneglycol, propyleneglycol, 1,3-butylene glycol, 1,4-butylene glycol, neopentyl glycol, diethylene glycol, triethylene glycol, 2,2,4-trimethyl-1,3-pentane diol, hexamethylene glycol, cyclohexane dimethanol, hydrogenated bisphenol-A, trimethylol propane, trimethylol ethane, 1,2,6-hexane triol, glycerine, sorbitol, pentaerythritol, reaction products of the aforementioned polyols with ethylene oxide, propylene oxide or mixtures thereof which reaction products have a weight-averaged molecular weight of 2000 g/mol or less, and combinations or these.

[0286] In other preferred embodiments, the odour control agent is an organic compounds having at least one isocyanate precursor group, wherein said isocyanate precursor group is a blocked isocyanate group, which can for instance be selected from allophanate groups, uretdione groups, isocyanurate groups, or is the product obtained from an addition reaction between an isocyanate group and a functional group selected from a primary, secondary or tertiary alcohol group, a secondary amine group, an oxime group, a lactam group, a phenolic hydroxyl group, an N-alkylamide group, an imide group, the carbon atom bonded to an acidic hydrogen atom in a C—H acidic compound.

[0287] Thus, the blocked isocyanate group can be the product obtained from an addition reaction between an isocyanate group and a compound selected from ethanol, isopropanol, tert-butanol, benzyl alcohol, lactic acid C1-C4 alkyl esters, tetrahydrofuryl alcohol, N-hydroxyethyl succinimide, di-n-butylamine, N-methyl-tert-butylamin, diisopropylamine, N-isopropyl-tert-butylamine, N-ethylisopropylamine, 2,2,6,6-tetramethylpiperidine, N-isoproyl-ter-butylamine, N-(tert-butyl)benzylamine, dicyclohexylamine, N-ethylisoproylamine, 4,4,-dimethyloxazolidin, N-isopropyl-tert-butylamine, phenol, o-methylphenol, alkyl esters of salicylic acid, ε-caprolactam, δ-valerolactam, γ-butyrolactam, formaldoxime, acetaldoxime, acetonoxim, 2-butanonoxime, 2-pentanonoxime cyclohexanone oxime, acetophenone oxime, benzophenone oxime, N,N-diethylhydroxylamin, diethyl glyoxime, N-methylacetamide, phthalimide, imidazole, pyrazole, 3-methylpyrazole, 4-nitro-3,5-dimethylpyrazole and 4-bromo-3,5-dimethylpyrazole, 3,5-dimethylpyrazol, triazole, 2-isoproyl-1H-imidazol, malonic acid C1-C4 alkyl esters, diethyl malonate, acetoacetic acid C1-C4 alkyl esters, acetylacetone.

[0288] Preferably, the blocked isocyanate group is the product obtained from an addition reaction between an isocyanate group and a compound selected from 3,5-dimethylpyrazol and 2-butanonoxime.

[0289] In other preferred embodiments, the odour control agent is a carboxylic acid hydrazide having 1-4 hydrazide groups in its molecular structure. The carboxylic acid hydrazide preferably is a hydrazide of an aliphatic monocarboxylic acid having 2-12 carbon atoms or a dihydrazide of an aliphatic dicarboxylic acid having 2-12 carbon atoms. For instance, the carboxylic acid hydrazide is selected from formhydrazide, acetohydrazide, propionic acid hydrazide, butanoic acid hydrazide, pentanoic acid hydrazide, benzoic acid hydrazide, salicylic acid hydrazide, naphthoic acid hydrazide, oxalic acid dihydrazide, carbodihydrazide, glutaric acid dihydrazide, succinic acid dihydrazide, adipic acid dihydrazide, dodecanedioic acid dihydrazide, fumaric acid dihydrazide, maleic acid dihydrazide, terephthalic acid dihydrazide, azelaic acid dihydrazide, sebacic acid dihydrazide, dodecanoic acid dihydrazide, tartaric acid dihydrazide, malic acid dihydrazide, isophthalic acid dihydrazide, dimer acid dihydrazide, citric acid trihydrazide, 1,2,4-benzenetricarboxylic acid dihydrazide, and a combination of these. A particularly preferred carboxylic acid hydrazide is adipic acid dihydrazide.

[0290] The amount of odour control agent present in the discharge printing agent can be suitably adapted by the skilled person taking into account the desired level of odour control and, furthermore, the desired wash fastness of the printed fabric. Since the odour control agent contains at least two moieties reactive under the conditions of heating the discharge printing agent applied to a fabric to a temperature of 100° C. or more, the odour control agent can form an oligomeric or polymeric material which adheres to the fabric and thus contributes to adhering any colouring agents optionally present in the discharge printing agent. Typically, the odour control agent (c) is preferably contained in an amount of 5-60% by weight relative to the weight of the sulfinic acid compound of formula (I), more preferably 10-50% by weight, even more preferably 20-40% by weight.

[0291] Odour control agent suitable for being used in the present invention are known to the skilled person, for instance from U.S. Pat. No. 5,693,737 A, EP 0 159 117 A1, EP 1 167 477 A1, EP 3 045 224 A1, or EP 1 900 788 A1, in which documents suitable odour control agents are described. Exemplary odour control agents that are commercially available are also mentioned in the Examples section hereinbelow.

[0292] (d) Water

[0293] There are no specific requirements to be fulfilled by the water present in the discharge printing agent and hence ordinary tap water could be used. However, it is preferred to reduce the ion content of the water, for instance by distillation or an ion-exchange treatment. That is, the water preferably is distilled or deionized water.

[0294] (e) Colouring Agent

[0295] As an optional component, the discharge printing agent can contain a colouring agent, i.e. an agent suitable for imparting the impression of colour on the printed fabric. The colouring agent should be chemically stable in the discharge printing agent, which implies that the colouring agent should be chemically stable in the presence of the reducing agent that is contained in the discharge printing agent. This includes that the colouring agent should be chemically stable in the discharge printing agent not only at room temperature, but also at a temperature of 100° C. or more and, preferably, at a temperature of 200° C., i.e. the temperature to which the discharge printing agent is exposed after having been applied to the fabric to be printed.

[0296] The colouring agent can for instance be a pigment or a dyestuff. From the viewpoint of chemical stability dyestuffs that do not contain an azo group, an anthraquinone substructure, a phthalocyanine substructure, a formazane substructure, or a dioxazine substructure are preferred.

[0297] The colouring agent can be a pigment such as a white pigment, for instance titanium dioxide. The colouring agent can also have a colour other than white and, preferably, a colour other than black. For instance, the colouring agent can have a yellow, red, green, blue, or purple colour. It is likewise possible that the discharge printing agent comprises a combination of two or more colouring agents, which combination of two or more colouring agents can in some embodiments comprise a white pigment, which white pigment can for instance be titanium dioxide. The combination of two or more colouring agents can in some embodiments comprise a colouring agent having a yellow, red, green, blue, or purple colour.

[0298] In general, the colouring agent is preferably present in discharge printing agent in an amount of 1-10% by weight, more preferably 2-8% by weight, relative to the total weight of the discharge printing agent. When a white pigment is present, either as the only colouring agent or in combination with at least one other colouring agent, the white pigment can be contained in an amount of 1-30% by weight relative to the total weight of the discharge printing agent, preferably 2-20% by weight, more preferably 3-15% by weight.

[0299] The discharge printing agent can furthermore comprise one or more of a humectant, a defoamer, a pH regulator, an emulsifier, and a catalyst. the humectant can for instance be urea and/or glycerol. The catalyst can for instance be a zinc salt of a carboxylic acid or a hydrated form of such a zinc salt, such as zinc citrate, zinc acetate or a hydrated form of these.

Aspect (2): Precursor Composition

[0300] In a second aspect, the present invention provides precursor composition for a discharge printing agent according to the first aspect of the invention as described hereinabove, said precursor composition comprising [0301] (a) a sulfinic acid compound of formula (I) as described with respect to the first aspect of the invention, [0302] and at least one of [0303] (b) a thickener as described with respect to the first aspect of the invention; and [0304] (c) an odour control agent as described with respect to the first aspect of the invention.

[0305] In preferred embodiments, the precursor composition is characterized by means of the following features. Preferred embodiments of the components contained in the precursor composition also become apparent from the description of preferred embodiments of the discharge printing agent according to first aspect of the invention as described hereinabove.

[0306] In preferred embodiments, the precursor composition comprises (b) said thickener and (c) said odour control agent.

[0307] When the precursor composition comprises said sulfinic acid compound of formula (I) and said odour control agent, the odour control agent (c) is preferably contained in an amount of 5-60% by weight relative to the weight of the sulfinic acid compound of formula (I), more preferably 10-50% by weight, even more preferably 20-40% by weight.

[0308] When the precursor composition comprises said thickener, it is preferred that the thickener is present in an amount such that a viscosity of 2500-150000 mPa.Math.s (more preferably 3000-15000 mPa.Math.s, even more preferably 4000-12000 mPa.Math.s) results after the precursor composition was dispersed in water in such an amount that said sulfinic acid compound of formula (I) represents 0.5-15% by weight relative to total weight of the precursor composition and the water. In alternative preferred embodiments, the thickener is present in an amount such that a viscosity of 25000-50000 mPa.Math.s (more preferably 25000-45000 mPa.Math.s) results after the precursor composition was dispersed in water in such an amount that said sulfinic acid compound of formula (I) represents 0.5-15% by weight relative to total weight of the precursor composition and the water. In more preferred embodiments, the thickener is present in an amount such that a viscosity of 2500-150000 mPa.Math.s (more preferably 3000-15000 mPa.Math.s, even more preferably 4000-12000 mPa.Math.s) results after the precursor composition was dispersed in water in such an amount that said sulfinic acid compound of formula (I) represents 1.0-12% by weight relative to total weight of the precursor composition and the water. In alternative more preferred embodiments, the thickener is present in an amount such that a viscosity of 25000-50000 mPa.Math.s (more preferably 25000-45000 mPa.Math.s) results after the precursor composition was dispersed in water in such an amount that said sulfinic acid compound of formula (I) represents 2.0-10% by weight relative to total weight of the precursor composition and the water. It is preferred to measure the viscosity using a Brookfield Viscometer DV-II at 20° C.

Aspect (3): Method of Preparing a Discharge Printing Agent

[0309] In a third aspect, the present invention provides a method of preparing a discharge printing agent according to the first aspect of the invention as described hereinabove, said method comprising a step of blending [0310] (a) a sulfinic acid compound of formula (I) as described with respect to the first aspect of the invention, [0311] (b) a thickener as described with respect to the first aspect of the invention, [0312] (c) an odour control agent as described with respect to the first aspect of the invention, and [0313] (d) water.

[0314] The amounts and/or properties of each of these components becomes apparent from the description of the discharge printing agent according to the first aspect of the invention.

[0315] The viscosity of the discharge printing agent obtained from this method generally is in the range of 2500-150000 mPa.Math.s.

[0316] In preferred embodiments, the precursor composition according to the second aspect of the invention as described hereinabove is used in order to provide [0317] (a) said sulfinic acid compound of formula (I), [0318] and at least one of [0319] (b) said thickener, and [0320] (c) said odour control agent.

Aspect (4): Discharge Printing Process

[0321] In a fourth aspect, the present invention provides a discharge printing process comprising the steps of [0322] (A) applying a discharge printing agent according to the first aspect of the invention as described hereinabove to a fabric dyed with a dischargeable dye in order to form a pattern of said discharge printing agent on said dyed fabric so as to give a dyed fabric comprising an undeveloped pattern; [0323] (B) exposing the undeveloped pattern on the dyed fabric to a temperature of 100° C. or more at a pressure that is equal to or higher than the pressure of the surrounding atmosphere so as to form a developed pattern on said dyed fabric;
wherein the steps are carried out in the sequence (A) to (B) and wherein further steps can optionally be present between these steps (A) and (B).

[0324] The preferred embodiments of said discharge printing agent used in step (A), inter alia such as amounts and/or properties of each of the components of said discharge printing agent, become apparent from the corresponding description of the first aspect of the invention.

[0325] In preferred embodiments, said dischargeable dye is a dye containing at least one of an azo group, an anthraquinone substructure, a phthalocyanine substructure, a formazane substructure, and a dioxazine substructure.

[0326] In some preferred embodiments, a step (A1) is carried out after said step (A) and before said step (B), which step (A1) is a step of allowing the water from the discharge printing agent present in said undeveloped pattern to evaporate at least partially.

[0327] Said step (B) preferably comprises exposing the undeveloped pattern on the dyed fabric to at least one of steam, hot air, and infrared irradiation, wherein it is more preferred to combine the exposure to infrared irradiation with the exposure to hot air. Exposure to the infrared irradiation is preferably carried out by using electromagnetic irradiation having a wavelength in the range of 700 nm to 1 mm.

[0328] The undeveloped pattern on the dyed fabric is preferably exposed in step (B) to a temperature of 200° C. or less, more preferably 180° C. or less, even more preferably 160° C. or less. In all these embodiments of the discharge printing process, it preferred that said step (B) is carried out for a period of 1-6 minutes.

Aspect (5): Fabric Comprising a Printed Pattern

[0329] In a fifth aspect, the present invention provides a dyed fabric comprising a pattern obtainable by a discharge printing process according to the fourth aspect of the invention as described hereinabove.

EXAMPLES

[0330] In the following, the present invention is illustrated by means of the following examples and comparative examples.

General Method for Preparing Discharge Printing Agents

[0331] A discharge printing agent was prepared by combining the constituents in a dissolver of type Dispermat® CN (commercially available from VMA-Getzmann GmbH, 51580 Reichshof, Germany) which was equipped with a toothed disc having a diameter of 50 mm. Blending was carried out a 1000 to 2000 rpm until a uniform mixture had formed. This usually took about 30 minutes. The pH was adjusted to 9 by adding pH regulators.

[0332] Subsequently, the discharge printing agent was stored at room temperature in a jar sealed with a screw cap for testing and evaluation.

[0333] The constituents and the respective amount (indicated in parts by weight) are shown in the tables 1 and 2. The constitution of the compositions referred as “Adjuvants A” and “Adjuvants B” are described in the table 3 and 4.

TABLE-US-00001 TABLE 1 Constitution of discharge printing agents (amounts in parts by weight) Compar- Compar- Compar- Compar- ative ative ative ative example 1 example 2 example 3 example 4 Adjuvants A 392.0 392.0 392.0 392.0 Thickener 1 48.0 48.0 48.0 48.0 Thickener 2 4.0 4.0 4.0 4.0 Reducing agent 1 — 100.0 — — Reducing agent 2 — — 100.0 — Reducing agent 3 — — — 100.0 Dispersant (=H.sub.2O) 514.0 514.0 514.0 514.0 Total 958.0 1058.0 1058.0 1058.0

[0334] In the discharge printing agent of comparative examples 1-4, Thickener 1 was added in an amount sufficient to impart a viscosity of 25000 mPa.Math.s. Then, Thickener 2 was added in an amount sufficient to increase the viscosity to about 43000 mPa.Math.s.

TABLE-US-00002 TABLE 2 Constitution of discharge printing agents (amounts in parts by weight) Compar- ative example 5 Example 1 Example 2 Example 3 Adjuvants B 257.6 257.6 257.6 257.6 Pigment suspension 100.0 100.0 100.0 100.0 Thickener 2 36.2 40.6 34.6 37.8 Odour control agent 1 — 100.0 — — Odour control agent 2 — — 100.0 — Odour control agent 3 — — — 25.0 Reducing agent 1 100.0 100.0 100.0 100.0 Dispersant (=H.sub.2O) 606.2 601.8 607.8 604.6 total 1100.0 1200.0 1200.0 1125.0

TABLE-US-00003 TABLE 3 Adjuvants A (amounts in parts by weight) Humectant 1 200.0 Defoamer 1 1.0 Emulsifier 5.0 Binder, acrylic dispersion 90.0 Catalyst for the reduction step 10.0 pH Regulator 2 10.0 Humectant 2 70.0 pH Regulator 1 6.0 total 392.0

TABLE-US-00004 TABLE 4 Adjuvants B (amounts in parts by weight) Humectant 1 50.0 Defoamer 2 1.0 Emulsifier 5.0 Wax emulsion 100.0 Adipate-based 30.0 plasticizer Humectant 2 70.0 pH Regulator 1 1.6 total 257.6

TABLE-US-00005 TABLE 5 Components used in the compositions of the examples and comparative examples (commercially available at CHT Germany GmbH, 72072 Tübingen, Germany, unless indicated otherwise). Component Thickener 1 Aqueous solution of hydroxyethyl cellulose (Prisulon CM 70) (solids content: 10%) Thickener 2 Acrylic polymer in aqueous dispersion (TUBIVIS DRL 170) (solids content: 50%) Reducing 2-hydroxy-2-sulfinatoacetic acid disodium salt agent 1 (solids content: 99%) Reducing Thiourea dioxide (Redulit F) agent 2 (solids content: 99% ) Reducing Zinc bis(hydroxymethanesulphinate) agent 3 (TUBISCREEN DC-AGENT) (solids content: 99%) Odour control Aqueous dispersion of dimethylpyrazol- agent 1 blocked isocyanate (TUBICOAT FIX H25) (solids content: 38%) Odour control Aqueous dispersion of a butanon oxime- agent 2 blocked isocyanate (TUBIFIX P 70) (solids content: 45%) Odour control Adipic acid dihydrazide (solids content: 99%) agent 3 Humectant 1 Aqueous urea solution 40% (solids content: 40%) Humectant 2 Glycerine (solids content: 99%) Defoamer 1 Silicone emulsion (TUBASSIST AF 237 W) (solids content: 32%) Defoamer 2 Mixture of organomodified polysiloxanes, fatty acids and polyglycol (Hansa ADD 5410) (solids content: 99%) pH Regulator 1 aqueous ammonia solution (25%) pH Regulator 2 Aqueous solution of diammonium hydrogen ortho-phosphate (solids content: 66%) Pigment Titanium dioxide suspension (TUBIPRINT suspension WEISS K 90) (solids content: 60%) Emulsifier Aryl ethylphenyl polyglycol ether (HANSA CARE A 60) (solids content: 32%) Binder, acrylic Acrylic polymer in aqueous dispersion dispersion (TUBICOAT A 12 E) (solids content: 60%) Catalyst for Zinkcitrate × 2 H.sub.2O reduction step (solids content: 95%) Wax emulsion Polyethylene dispersion (HANSA LPW 465) (solids content: 30%) Adipate-based Adipate-based plasticizer Bis(2-ethylhexyl) plasticizer adipate (TUBISOFT VST) (solids content: 99%) Solids content was determined by drying at 105° C.

General Method of Printing Using the Exemplary Discharge Printing Agents

[0335] Printing was tested using a knitted cotton fabric dyed black in a screen printing method which was carried out using a magnetic printing table of type MBK FAM C 27 (commercially available from mbk Maschinenbau GmbH, 88353 Kisslegg, Germany) with the following settings. [0336] Squeegee speed: 6 m/min [0337] Squeegee roll diameter: 10 mm [0338] Squeegee pressure: 6 (setting on a scale ranging from 1 to 6, without units) [0339] Stencil gauze: 43T [0340] Stencil motif: A4 [0341] Number of squeegee passes: 1

[0342] Fixation of the printed pattern was effected by dry heating to a temperature of 160° C. for 4 minutes at a fan speed of 2220 rpm using a labcoater of type Mathis LTE (commercially available from Werner Mathis AG, 8156 Oberhasli, Switzerland).

[0343] Printing results were evaluated as described hereinbelow.

[0344] The printed fabric was also evaluated according to the following procedure for olfactory examination.

Procedure for Olfactory Examination of Fabric Samples

[0345] The test for evaluating the efficiency of odour control by the odour control agent contained in the discharge agent printing agent was carried out in the following manner.

[0346] 30 ml of distilled water are placed in a wide-necked jar having a capacity of 1 litre. The jar is sealed with a screw lid having a metal hook attached to the surface facing towards the interior volume of the jar and the sealed jar is placed in an oven at a temperature of 40° C. for a period of 15 minutes.

[0347] As the sample of the printed fabric to be tested is obtained by cutting from the printed fabric a piece having a size of 15 cm×21 cm. In order to ensure that the test results are reliable and reproducible, it is understood that the piece of 15 cm×21 cm is cut from the fabric in such a manner that the cut piece consists of printed fabric, i.e. no part of the cut piece of fabric has not been treated with the discharge printing agent to be tested. A hole having a diameter of 6 mm was punched into the each corner of the sample. The sample is folded and attached to the hook of the screw lid of the jar in such a manner that contact of the sample with the water and/or the interior walls of the jar is avoided. The screw lid is put in place onto the jar and screwed down such that the jar is closed tightly.

[0348] At the same time, a control sample is prepared by cutting a sample having the same size (15 cm×21 cm) from unprinted fabric. Hole are punched into the control sample and the control sample is folded and attached to the hook of the screw lid of the jar in the same manner as described for the sample of the printed fabric to be tested. The screw lid is put in place onto the jar and screwed down such that the jar is closed tightly.

[0349] The jar holding the sample and the jar holding the control sample are stored in an oven at a temperature of 40° C. over a period of 2 hours. Subsequently, the jars are removed from the oven and allowed to cool to room temperature. This usually takes about 10 minutes.

[0350] After the jars have cooled to room temperature, the sample and control sample are removed from the respective jar and handed to a panel of 3 persons. Each person evaluates the odour of each sample according to the following rating scheme as regards its intensity and its characteristics. [0351] Rating 1: not noticeable [0352] Rating 2: perceptible, but not unpleasant [0353] Rating 3: clearly perceptible, but not yet unpleasant [0354] Rating 4: unpleasant [0355] Rating 5: very unpleasant [0356] Rating 6: intolerable

[0357] After the evaluation, each sample is stored in a sealable plastic bag which is sealed for any later testing as suitable or necessary.

Evaluation of the Exemplary Discharge Printing Agents

[0358] Viscosity of the discharge printing agent was measured using a Brookfield Viscometer DV-II (commercially available from AMETEK Brookfield, Middleboro, MA 02346, USA) at 20° C. and revolutions per minute using a RV-spindle selected according to the following table on basis of the expected viscosity of the sample. The measured values is read after a measurement period of 30 seconds. If it is found after said measurement period of 30 seconds that a different spindle should have been used because the measured viscosity does not fall within the expected range, the spindle is exchanged accordingly and the measurement is repeated.

TABLE-US-00006 Expected viscosity range No. of RV-spindle [mPa .Math. s] to be used 4000-8000  4 8000-16000 5 16000-40000  6 40000-160000 7

[0359] Viscosity was measured about 4 hours and about 24 hours after preparing the discharge printing agent.

[0360] Likewise, pH was measured using a pH-meter of type WTW pH 540 GLP (commercially available from Xylem Inc., Rye Brook, NY 10573) about 4 hours and about 24 hours after preparing the discharge printing agent.

[0361] The printing results of the discharge printing agents of examples 1-3 and comparative examples 1-5 were evaluated by carrying out colour measurements in the CIE L*a*b* colour space using a Konica Minolta Spectrophotometer CM 600d (commercially available from Konica Minolta Business Solutions Deutschland GmbH, 30855 Langenhagen, Germany). However, since printing was carried out on black fabric with a discharge printing agent containing titanium dioxide, i.e. a white pigment, only the lightness value L* was recorded. In the CIE L*a*b* colour space, a lightness value L*=0 represents the darkest black and a lightness value L*=100 represents the brightest white.

TABLE-US-00007 TABLE 6 Evaluation of discharge printing agents Compar- Compar- Compar- Compar- ative ative ative ative t example 1 example 2 example 3 example 4 pH 0 9.0 9.0 9.0 9.0 <4 h 8.3 8.6 3.7 4.8 ≈24 h 8.3 8.6 3.7 4.7 Viscosity 0 43000 43000 43000 43000 [mPa .Math. s] <4 h 43800 41600 29200 28800 ≈24 h 42800 41200 26400 29000 L* <4 h 17 56 22 64 (printed ≈24 h 17 54 21 63 fabric)

[0362] In comparative examples 1-4, the pH, the viscosity and the printing results were tested less than 4 hours and 24 hours after the discharge printing agent had been prepared as indicated by means of parameter t. That is, testing of the discharge printing agent was carried out at the point of time t, with t=0 being the time of preparation of the discharge printing agent. For instance, it is indicated in table 6 that the lightness value L* of printed fabric was measured using the discharge printing agent of comparative example 1-4 less than 4 hours after the discharge printing agent had been prepared (t<4 h) and 24 hours after the discharge printing agent had been prepared (t≈24 h).

[0363] It was found that the pH significantly changed in the comparative examples 3 and 4 during storage of the discharge printing agent. While the pH had been set to 9 during preparation of each discharge printing agent, values as low as 3.7 were observed after a storage time of 24 hours. Likewise, the viscosity decreased from 43000 mPa.Math.s to values as low 26400 mPa.Math.s within 24 hours of storage.

[0364] The L* value of the black-dyed fabric used in the test for printing was 17, which did not change in comparative example 1. The corresponding discharge printing agent did not contain a reducing agent that could have affected the black dye in the fabric. The L* value of fabric did not significantly increase in comparative example 3, which indicates that the reducing agent used was almost completely ineffective. This is presumably the result of a premature deterioration of the reducing agent which also resulted in an undesirable decrease of the pH and, as a consequence, in a decrease of the viscosity.

[0365] Only in comparative example 2 (in which a discharge printing agent containing 2-hydroxy-2-sulfinatoacetic acid disodium salt as the reducing agent was tested), satisfactory stability of pH and viscosity in combination with good brightening effect (as a result of the reduction of the black dye) was observed.

TABLE-US-00008 TABLE 7 Evaluation of discharge printing agents Compar- ative example 5 Example 1 Example 2 Example 3 pH  <4 h 8.9 8.9 8.8 8.9 Viscosity  <4 h 4260 11080 4520 5350 [mPa .Math. s] L* ≈24 h 54.5 56.7 52.3 48.2 (printed fabric) Olfactory ≈24 h 3-4 2 2 1-2 examination

[0366] In comparative example 5 and examples 1-3, the pH, the viscosity and the printing results were tested at the time of preparation, less than 4 hours and 24 hours after the discharge printing agent had been prepared as indicated by means of parameter t. No significant change of pH and viscosity were observed.

[0367] In comparative example 5, satisfactory stability of pH and viscosity in combination with good brightening effect (as a result of the reduction of the black dye) was observed. However, the olfactory examination of the printed fabric gave unsatisfactory results as an odour could be clearly perceived.

[0368] In examples 1-3, satisfactory stability of pH and viscosity in combination with good brightening effect (as a result of the reduction of the black dye) was observed. Likewise, the olfactory examination gave good results. While the highest brightening effect was observed in example 1, the best result of the olfactory examination was observed in example 3.