FORMALDEHYDE-FREE, AQUEOUS COMPOSITION FOR DISCHARGE PRINTING OF FABRIC

Abstract

The present invention relates to a composition for discharge printing of fabric, a discharge printing process for printing said composition to the fabric, the use of the composition for discharge printing and to a fabric treated with the composition in a discharge printing process according to the invention.

Claims

1. A formaldehyde-free, aqueous composition for discharge printing of fabric, the composition comprising: at least one reducing agent, at least one synthetic thickener, at least one wetting agent, at least one pH modifier, optionally at least one pigment, and optionally at least one binder.

2. The composition according to claim 1, wherein the at least one synthetic thickener is a polyacrylic compound.

3. The composition according to claim 1, wherein the at least one binder is based on poly(butyl acrylate), copolymer of two or more of butyl(acrylate), ethyl(acrylate) and styrene, polyvinyl acrylate, acrylonitrile, or mixtures thereof.

4. The composition according to claim 1, wherein the wetting agent is selected from urea, glycerin, or mixtures thereof.

5. The composition according to claim 1, wherein the reducing agent comprises a sulfinic acid derivative.

6. The composition according to claim 1, further comprising one or more components selected from the group of crosslinking agents, softeners, emulsifiers, antifoaming agents, rheology modifiers, oxidation protection agents, or a mixture thereof.

7. The composition according to claim 1, wherein the composition is free from any natural thickener.

8. The composition according to claim 1, wherein the composition comprises from 3 to 30% by weight of the at least one reducing agent, from 0.05% to 6% by weight of the at least one synthetic thickener, from 3 to 45% by weight of at the least one wetting agent, from 0.05 to 4% by weight of the at least one pH modifier, from 0 to 30% by weight of the at least one binder, from 0 to 2% by weight of at least one emulsifier, from 0 to 1% by weight of at least one anti foaming agent, from 0 to 3% by weight of at least one crosslinking agent, from 0 to 3% by weight of at least one softener, from 0 to 2% by weight of at least one rheology modifier, from 0 to 2% by weight of at least one oxidation protection agent, from 0 to 6% by weight of at least one pigment dispersion, and the remainder to 100% by weight is water, wherein the % by weight is based on the total weight of the composition.

9. A process for manufacturing a formaldehyde-free, aqueous composition for discharge printing of fabric comprising the following Step A and optionally Steps B and C: Step A: Mixing and homogenizing all components for the composition including: at least one reducing agent, at least one synthetic thickener, at least one wetting agent, at least one pH modifier, optionally at least one pigment, and optionally at least one binder, in case the at least one pigment is present in the composition, then further comprising Step B: Adding at least one dispersion comprising the at least one pigment to the mixture obtained in Step A, and Step C: Mixing and homogenizing the mixture obtained in Step B.

10. A method of using the formaldehyde-free, aqueous composition of claim 1 for a discharge printing processes.

11. A discharge printing process for printing fabric, the process comprising the following steps: Step 1: providing a colored fabric, Step 2: in a printing step, printing the colored fabric using the formaldehyde-free, aqueous composition according to claim 1, Step 3: in a first drying step, drying the fabric obtained in step 2, Step 4: in a washing step, washing the fabric obtained in step 3, wherein the fabric is rinsed with a rinsing fluid and/or is soaped with a soaping fluid, and Step 5: in a second drying step, drying the fabric obtained in step 4.

12. The process of claim 11, wherein the washing step comprises a first cold and/or hot rinsing step wherein the printed fabric is rinsed with a rinsing fluid selected from cold water or aqueous H.sub.2O.sub.2 solution and/or, a hot soaping step wherein the printed fabric is washed with a soaping fluid, selected from soapy water at temperatures from 40 to 80? C. and/or, a second cold rinse step wherein the printed fabric is rinsed with a second rinsing fluid selected from cold water.

13. The process according to claim 11, wherein the first drying step is performed at temperatures from 140? C. to 180? C., and/or wherein the second drying step is performed at temperatures of from 120? C. to 160? C.

14. The process according to claim 11, wherein the process does not comprise a curing step and or a steaming step.

15. Fabric treated with a composition according claim 1.

16. The composition according to claim 1, wherein the at least one synthetic thickener is an acrylic acid copolymer.

17. The composition according to claim 1, wherein the at least one synthetic thickener includes high density oil and auxiliaries.

18. The method according to claim 10 wherein the discharge printing processes include white discharge or color discharge printing processes of fabric.

19. The process according to claim 11 wherein the first drying step is performed for 1 to 5 minutes and/or wherein the second drying step is performed for 8 to 20 minutes.

Description

[0136] Reference is made in this respect to FIGS. 1 and 2

[0137] FIG. 1 shows fabric samples treated in a color discharge process according to the invention using a composition according to the invention and comparatively fabric samples treated in a benchmark process using a benchmark composition. FIG. 1 demonstrates the higher color fastness of fabric samples worked according to the invention.

[0138] FIG. 2a shows a white discharge fabric sample and a color discharge fabric sample respectively worked in discharge processes according to the invention using respectively a composition for white discharge printing and color discharge printing according to the invention.

[0139] FIG. 2b shows a white discharge fabric sample and a color discharge fabric sample respectively worked according to a benchmark discharge processes known in the art using respectively benchmark compositions for white discharge printing and color discharge printing as also known in the art.

EXAMPLES

Example 1: Preparation of a Composition According to the Invention for Discharge Printing

[0140] In a first step A, a mixing vessel equipped with a blade stirrer was charged under stirring according to the specifications shown in table 1:

TABLE-US-00001 TABLE 1 white color Mixing discharge discharge Component Function Order [g/kg] [g/kg] Luprintol? Emulsifier PE liq c emulsifier 1 6 6 Antimussol? UDF (1:10) defoamer 2 1 1 Triethanolamine pH modifier 3 10 10 Gycerine wetting agent 4 50 50 Urea wetting agent 5 200 200 Helizarine? LTC liq binder 6 180 Luprintol? fixing agent SE.01 liq crosslinking agent 7 10 10 Luprintol? Soft VSN liq softener 8 5 5 Luprintol? Additive RM liq rheology modifier 9 5 5 Revatol NS liq ox. Protection agent 10 5 5 Rongalit? ECO p reducing agent 11 100 100 Lutexal? GP ECO p thickener 12 20 20 Printofix? T-B pigment 13 20 Water fluid carrier 14 408 388 ?1000 ?1000

1.1 Composition for White Discharge Printing

[0141] After subsequent mixing of components 1 to 12 and 14, stirring was continued for another 20 min at 2000 r/min until a final viscosity of 3,500 mPa.Math.s was reached. The pH value of the composition was pH=8.5.

1.2 Composition for Color Discharge Printing

[0142] After subsequent mixing of components 1 to 12 and 14, stirring was continued for another 20 min until a final viscosity of 3,500 mPa.Math.s was reached. The pH value of the composition was pH=8.6. [0143] In a second step B a dispersion comprising the pigment Printofix T-B was added under stirring to the composition obtained in the first step A. [0144] In a third step C the mixture of step B was mixed and homogenized under stirring.

Comparative Example 1: Benchmark Composition

[0145] A benchmark composition was prepared comprising a Zinc formaldehyde sulfoxylate and a natural thickener instead of the reducing agent and thickener of Example 1 as commonly used in the art for discharge printing processes.

[0146] In a first step A, a mixing vessel was charged under stirring according to the specifications shown in table 2:

TABLE-US-00002 TABLE 2 white color Mixing discharge discharge Component Function Order [g/kg] [g/kg] gycerin wetting agent 1 50 50 Ammonium sulphate (1:2) 2 50 50 Natural guar gum thickener 8% thickener 3 500 500 Zinc formaldehyde sulfoxylate reducing agent 4 100 100 Acrylate binder binder 5 180 Printofix? T-B pigment 6 20 Water fluid carrier 7 408 388 ?1000 ?1000

1.1 Composition for White Discharge Printing

[0147] After subsequent mixing of components 1 to 5 and 7, stirring was continued for another 10 hours at 2000 r/min until a final viscosity of 3,500 mPa.Math.s was reached.

1.2 Composition for Color Discharge Printing

[0148] After subsequent mixing of components 1 to 5 and 7, stirring was continued for another 10 hours min until a final viscosity of 3,500 mPa.Math.s was achieved. [0149] In a second step B a dispersion comprising the pigment Printofix T-B was added under stirring to the composition obtained in the first step A. [0150] In a third step C the mixture of step B was mixed and homogenized under stirring.

Example 2: Discharge Printing Process According to the Invention

[0151] A ground dyed satin cotton fabric, 100 gr/m.sup.2 fabric was provided

2.1 White Discharged Fabric

[0152] The fabric was provided as a fabric web wound on a fabric roll. The fabric was unwound and was guided through a printing unit at a conveyor speed of 20 m/min. In the printing unit the under Example 1.1 obtained printing composition was applied to the fabric by conventional flat screen-printing method (J. Zimmer, GmbH; AustriaMini MDF/796). After running through the printing unit, the fabric was conveyed to a drying unit. Drying and fixation of the prints were made by drying at 160? C. for 2 min. The fabric web was conveyed out of the drying unit and was rewound to a fabric roll. Subsequently, the printed fabric web was subjected to washing. The fabric web roll was unwound, and the fabric web was conveyed through a washing unit at a conveyor speed of 40 m/min. In the washing unit the fabric was cold rinsed with water and subsequently rinsed with an 1 g/l aqueous H.sub.2O.sub.2 solution (w:v) at 40? C. and 60? C. for 10 minutes respectively. After that the fabric web was washed for 10 minutes in soapy water at 70? C. comprising 1 g/l (w:v) of an anionic soaping agent (Kieralon Jet B conc. liq.). Subsequently the fabric web was rinsed with cold water for 10 minutes, was air dried and was rewound to a fabric roll.

2.2 Color Discharged Fabric

[0153] The process of Example 2.1 was repeated except that a composition obtained according to Example 1.2 was used in the discharge printing process instead of the composition obtained in Preparation Example 1.1.

Comparative Example 2: Benchmark Printing Process

[0154] A benchmark printing process was performed as commonly applied in the art.

2.1 White Discharge Fabric

[0155] The ground dyed fabric of Example 2 was provided as a fabric web wound on a fabric roll. The fabric was unwound and was guided through a printing unit at a conveyor speed of 20 m/min. In the printing unit the printing composition obtained under Comparative Example 1.1 obtained was applied to the fabric by conventional flat screen-printing method (J. Zimmer, GmbH; AustriaMini MDF/796). After running through the printing unit, the fabric was conveyed to a drying unit. Drying and fixation of the prints were made by drying at 135? C. for 1 min, steamed at 102? C. for 10 min and cured at 150? C. for 5 min. The fabric web was conveyed out of the drying unit and was rewound to a fabric roll. Subsequently, the printed fabric web was subjected to washing. The fabric web roll was unwound, and the fabric web was conveyed through a washing unit at a conveyor speed of 20 m/min. In the washing unit the fabric was cold rinsed with water and subsequently rinsed with an 1 g/l aqueous H.sub.2O.sub.2 solution (w:v) at 40? C. and 60? C. for 10 minutes, respectively. After that the fabric web was washed in soapy water at 70? C. comprising 1 g/l (w:v) of an anionic soaping agent (Kieralon Jet B conc. liq.) for 20 minutes. Subsequently the fabric web was rinsed with cold water for 30 minutes, was air dried and was rewound to a fabric roll. The washing time needed is at least twice as long as in Example 2.1.

2.2 Color Discharge Fabric

[0156] The process of Comparative Example 2.1 was repeated except that a composition obtained according to Comparative Example 1.2 was used in the printing process instead of the composition obtained in Comparative Example 1.1.

[0157] Examples 2.1 and 2.2 and Comparative Example 2.1 and 2.2 were compared with regard to the desired end points of the printing process according to the invention, i.e. contamination of zinc derivatives, release of formaldehyde, energy consumption and process time.

TABLE-US-00003 TABLE 3 Printing process Benchmark according to the printing End point invention process Zinc derivatives n.d. 897 ppm Formaldehyde, before washing n.d. 2682 ppm Formaldehyde, after washing n.d. 189 ppm Energy consumption ?45% reference Process time ?47% reference

[0158] Zinc occurrence was determined according to EN 16711-2:2016. Occurrence of formaldehyde was determined according to AATCC 112. Data of table 3 show that any zinc or formaldehyde contaminations were not detectable for the printing process according to the invention. Further, energy consumption and process time can be almost reduced to the half according to the printing process according to the invention.

Example 3: Color Fastness and Color Strength of Fabric Samples Worked According to the Invention

[0159] 3.1 Fabric samples printed according to the color discharge process of Example 2.2 were prepared and were investigated due to their rubbing fastness. [0160] Fabric samples prepared according to Example 2.2 were subjected to domestic laundering at 60? C. Subsequently those samples were subjected to dry and wet rub fastness measuring according to ISO 105/X12. [0161] The fabric samples exhibited a dry rub fastness of grade 4.2 and a wet rub fastness of grade 2.9. [0162] 3.2 The relative colour strength (K/S) of printed fabrics was measured by the light reflectance technique using the Kubelka-Munk equation. The reflectance (R) of printed fabrics was measured on a Konica Minolta MF-3700d (Japan). The color strength of the samples were determined to be increased of at least 27% compared to the following Comparative Example 3.

Comparative Example 3: Color Fastness and Color Strength of Fabric Samples Worked According to Benchmark Process

[0163] 3.1 Fabric samples printed according to the color discharge process of Comparative Example 2.2 were prepared and were investigated due to their rubbing Fastness. [0164] Fabric samples prepared according to Comparative Example 2.2 were subjected to domestic laundering at 60? C. Subsequently those samples were subjected to dry and wet rub fastness measuring according to ISO 105/X12. [0165] The fabric samples exhibited a dry rub fastness of grade 3.2 and a wet rub fastness of grade 2.4. [0166] 3.2 The relative colour strength (K/S) of printed fabrics was measured by the light reflectance technique using the Kubelka-Munk equation. The reflectance (R) of printed fabrics was measured on a Konica Minolta MF-3700d (Japan).

[0167] Test results of Example 3 and Comparative Example 3 are shown in FIG. 1. As can be seen from FIG. 1, dry and wet rub fastness of fabric samples worked according to the invention are visibly improved over the fastness levels achieved by the benchmark discharge process. Further, as visible from FIG. 1, the color strength of samples worked according to Example 3 is more pronounced than those worked according to Comparative Example 3.

Example 4: Discharge Quality, Sharpness and Brilliance

[0168] Fabric samples worked according to Examples 2.1, Example 2.2 and Comparative fabric samples worked according to Comparative Examples 2.1 and 2.2 were compared with regard to discharge quality, sharpness and brilliance. Visibly inspections of samples worked according to the invention as shown in FIG. 2a and samples worked according to known benchmark processes and compositions as shown in FIG. 2b were made. The following observations were made: [0169] The white discharge sample worked according to Example 2.1 shows significant less yellowing over the white discharge sample worked according to Comparative Example 2.1. The discharge printing quality, i.e. the whitening, achieved with the composition and the process according to the present invention is therefore improved over known benchmark systems. [0170] Color discharge samples worked according to Example 2.2. were identified to have brighter color appearance over color discharge samples worked according to Comparative Example 2.2. Brilliance of colors of samples worked according to Example 2.2. is improved over the benchmark sample. Without being bound to theory it is believed that composition and printing process according to the invention produces less dye/pigment degradation compared to known benchmark systems. [0171] A sharpened print pattern for white discharge and color discharge samples worked according to Examples 2.1 and 2.2 was observed over samples worked according to Comparative examples 2.1 and 2.2. Sharpness quality of samples worked according to the invention is therefore improved over the comparative samples.