CROSSLINKABLE AQUEOUS POLYMER DISPERSIONS WITH AMINOACID CROSSLINKER FOR TEXTILE

Abstract

The invention relates to an aqueous coating composition, comprising: a) an aqueous polymer dispersion with said polymer containing monomeric units of at least one dicarboxylic acid monomer, bearing two carboxylic acid functional groups and said polymer remaining insoluble in water after neutralization and remaining in the form of dispersed polymeric particles having a mean particle size varying from 10 to 1000 nm, b) a crosslinker selected from aminoacids bearing at least two amino functional groups capable of reacting with said carboxylic functional groups. It also relates to its use in the treatment of flexible fibrous substrates, a method for and the coated or treated fibrous substrate.

Claims

1. An aqueous coating composition comprising: a) an aqueous polymer dispersion with said polymer containing less than 20% in mol with respect to the total number of moles of monomeric units in said polymer, of monomeric units of at least one di carboxylic acid monomer, bearing two carboxylic acid functional groups and said polymer remaining insoluble in water after neutralization and remaining in the form of dispersed polymeric particles having a mean particle size varying from 10 to 1000 nm, b) a crosslinker selected from aminoacids bearing at least two amino functional groups capable of reacting with said carboxylic functional groups, said coating composition being free of any added catalyst (0%) for the reaction between said amino groups of said crosslinker and said carboxy groups of said polymer and able to cure at a pH range lower than 6.

2. The aqueous coating composition according to claim 1, wherein said polymer a) comprises monomeric units from the following monomers: a1) at least one ethylenically unsaturated monomer selected from the group consisting of acrylic and vinylic monomers, a2) at least one ethylenically unsaturated monomer different from a) and bearing at least two carboxylic acid functional groups at a weight content with respect to the total weight of said copolymer of from 0.1% to 15%.

3. The aqueous coating composition according to claim 2, wherein said monomer a2) is a dicarboxylic acid or anhydride monomer selected from the group consisting of: maleic acid and anhydride, fumaric acid, itaconic acid and anhydride, tetrahydro phthalic acid and anhydride (cis 4-cyclohexene, 1,2-dicarboxylic acid and anhydride).

4. The aqueous coating composition according to claim 2, wherein said monomer a2) is itaconic acid or anhydride.

5. The aqueous coating composition according to claim 2, wherein said monomer a1) comprises at least one selected from the group consisting of C1-C18 alkyl (meth)acrylates, hydroxy alkyl C2-C4 (meth)acrylates, ureido-acetoacetate-diacetone-amido-functional (meth)acrylic and vinylic monomers, (meth)acrylic acid, vinyl acetate, vinyl fumarate, styrene, acrylonitrile, unsaturated silane, maleate, and butadiene.

6. The aqueous coating composition according to claim 1, wherein the molar ratio of the amino groups of said crosslinker b) to the carboxy groups of said polymer of dispersion a) is of at least 0.1.

7. The aqueous coating composition according to claim 1, wherein said aqueous polymer dispersion a) has a solids content of from 25 to 60% by weight with respect to the weight of said dispersion a).

8. The aqueous coating composition according to claim 1, wherein said crosslinker b) is selected from: asparagine, arginine, glutamine, histidine, lysine, and tryptophan.

9. (canceled)

10. (canceled)

11. (canceled)

12. A method of coating or treating a flexible fibrous substrate, comprising successive steps-: i) coating said flexible fibrous substrate with the aqueous coating composition as defined in claim 1, either by impregnation or by spraying or by using a coater ii) curing by coating composition heating the resulting substrate at a temperature in the range from 100 to 230° C., without any addition of any catalyst of the curing reaction, and iii) cooling the resulting coated or treated flexible substrate to ambient temperature.

13. A coating resulting from the crosslinking (cure) by said crosslinker b) of the coating composition as defined according to claim 1.

14. A coated or treated flexible fibrous substrate, resulting from the method defined according to claim 12.

15. A coated or treated flexible substrate of claim 14, selected from woven and non-woven fibers, fabrics, textile, paper, cardboard and glass fibers.

Description

EXAMPLE 1 OR EX 1: (NMA-CONTAINING LATEX)

[0075] 1904 g of deionized water are added to a glass reactor fitted with a condenser, a stirrer, a temperature control system and inlets for nitrogen, the initiator solutions and the pre-emulsion feed, respectively. A monomer pre-emulsion composed of 1244 g of deionized water, 110 g of a 40% strength solution of MERSOLAT H95, 3267 g of ethyl acrylate and 172 g of a 48% strength N-methylol-acrylamide solution is prepared in another container fitted with a stirrer (pre-emulsifier).

[0076] When the contents of the reactor have reached a temperature of 60° C., 212 g of the monomer pre-emulsion and 19 g of 10% sodium persulfate aqueous solution, 0,012 g of Iron sulfate heptahydrate and 0.52 g of sodium metabisulfite dissolved in 15 g of water are added into the reactor. About one minute after the addition of initiator, the remaining portion of the monomer pre-emulsion, 390 g of 5% sodium persulfate aqueous solution and 2.8 g of sodium metabisulfite dissolved in 93 g of water are fed constant rate into the reactor over a period of 3 hours. Taking care to keep the contents of the reactor at a temperature of 60-68° C. throughout the introduction. Then, the reacticn medium is maintained at 60-68° C. for a further 60 minutes after that 53 g of 13% tert-butyl hydroperoxide and 128 g of a 4% Bruggolite® E01 solution are fed separately into the reactor at 60° C. over a period of 90 minutes at constant rate.

[0077] Fifteen minutes after the end of the above addition, the product obtained is cooled to 35° C. At the end, the mixture is filtered through ascreen of 36 mesh.

[0078] The pH and solids content are adjusted respectively with ammonia to be between 5.0 and 7.0 and demi water to about 45%.

[0079] The dispersion obtained has a pH of 6.5, a viscosity (Brookfield RVT at 20 rpm and at 23° C.) of 100 mPa.Math.s, a dry residue solids contentof 45.0% by weight (1 h at 105° C.) and particle size of 200 nm.

[0080] This dispersion contains only 2.5% of N-methylol acrylamide on total monomers, (2.5% on mol base).

EXAMPLE 2 OR EX 2: ITACONIC ACID-CONTAINING LATEX

[0081] 1904 g of deionized water are added to a glass reactor fitted with a condenser, a stirrer, a temperature control system and inlets for nitrogen, the initiator solutions and the pre-emulsion feed, respectively. A monomer pre-emulsion composed of 1321 g of deionized water, 117 g of a 40% strength solution of MERSOLAT H95, 3274 g of ethyl acrylate g and 101 g of itaconic acid is prepared in another container fitted with a stirrer (pre-emulsifier).

[0082] When the contents of the reactor have reached a temperature of 60° C., 212 g of the monomer pre-emulsion and 19 g of 10% sodium persulfate aqueous solution, 0,012 g of Iron sulfate heptahydrate and 0.52 g of sodium metabisulfite dissolved in 15 g of water are added into the reactor. About one minute after the addition of initiator, the remaining portion of the monomer pre-emulsion, 390 g of 5% sodium persulfate aqueous solution and 2.8 g of sodium metabisulfite dissolved in 93 g of water are fed constant rate into the reactor over a period of 3 hours. Taking care to keep the contents of the reactor at a temperature of 60-68° C. throughout the introduction. Then, the reacticn medium is maintained at 60-68° C. for a further 60 minutes after that 53 g of 13% tert-butyl hydroperoxide and 143 g of a 6% Bruggolite® FF6 solution are fed separately into the reactor at 60° C. over a period of 90 minutes at constant rate.

[0083] Fifteen minutes after the end of the above addition, the product obtained is cooled to 35° C. At the end, the mixture is filtered through ascreen of 36 mesh.

[0084] The pH and solids content are adjusted respectively with ammonia to be between 5.0 and 6.0 and demi water to about 45%.

[0085] The dispersion obtained has a pH of 4.2 a viscosity (Brookfield RVT at 20 rpm and at 23° C.) of 58 mPa.Math.s, solids content of 46.7% by weight (1 h at 105° C.) and particle size of 170 nm.

[0086] This dispersion contains only 3% of itaconic acid on total monomers, (2.3% on mol base).

EXAMPLE 3 OR EX 3 (EX 2+LYSINE): AQUEOUS DISPERSION OF EXAMPLE 2 WITH ADDED LYSINE ACCORDING TO THE INVENTION

[0087] To 1000 g of the polymer dispersion of example 2, we add 14.4 g of L-Lysine dissolved in 40 g of demineralized water.

[0088] The dispersion obtained has a pH of 5.5, a viscosity (Brookfield RVT at 20 rpm and at 23° C.) of 55 mPa.Math.s, a solids content of 45.5% byweight (1 h at 105° C.) and particle size of 170 nm.

[0089] This dispersion contains only 3% of itaconic acid on total monomers (2.3% on mol base) and 3.2% of L Lysine on total monomers (2.3% on mol base).

EXAMPLE 4 OR EX 4 (EX 2+ARGININE): AQUEOUS DISPERSION OF EXAMPLE 2 WITH ADDED ARGININE ACCORDING TO THE INVENTION

[0090] To 1000 g of the polymer dispersion of example 2, we add 17.6 g of L Arginine dissolved in 100 g of demineralized warm water.

[0091] The dispersion obtained has a pH of 5.5, a viscosity (Brookfield RVT at 20 rpm and at 23° C.) of 56 mPa.Math.s, a dry residue (solids content) of 42.2% by weight (1 h at 105° C.) and a pre-coagulate content on a screen of 275 mesh of about 150 ppm and particle size of 170 nm.

[0092] This dispersion contains only 3% of itaconic acid on total monomers (2.3% on mol base) and 3.9% of L Arginine on total monomers (2.3% on mol base).

Characterization of the polymer films: conditions and test methods used

[0093] The tests carried out on the polymer films are:

1) Determination of the maximum tensile strength and the elongation at break according to DIN standard 53455, using a type 4 test sample and a traction speed of 300 mm/min, both in the dry state and after swelling the test samples in water for 7 days, before and after crosslinking at 170° C. for 5′ in avented oven.
2) Determination of water, ethanol and acetone absorption.

[0094] It was carried out by dipping specimen having 2 cm×2 cm sizes and about 1 g weight in the specific solvent.

[0095] The specimens were weighed before dipping and weighed again after a time of 7 days for water, 8 hours for the other solvents, after having removed, with paper towels, the possible liquid present on their surface.

[0096] These tests have been carried out before and after crosslinking at 170° C. for 5′ in a vented oven.

[0097] The lower is the value of absorption the higher is the crosslinking (crosslink density). It is particularly important the decrease of these values after thermal treatment (crosslinking).

3) Dynamic Mechanical Analysis (DMA)

[0098] The measure of dynamic modulus E′ (storage modulus) of the polymer films dried 7 days at 23° C., obtained from the dispersions of the examples 1-4 versus temperature, has been carried out on specimen of polymer films of dimension of about 6.0×2.0×25.0 mm. The measures have been done by using a dynamic mechanical analyzer DMA 242 E1G Artemis NETZSCH with dual cantilever geometry on a temperature range from −60 to 200° C. The results of E′ vs temperature are shown in FIG. 1.

[0099] The thermal crosslinking is evidenced by the increase of modulus E′ with respect to same film without any crosslinking (see examples 3 and 4 vs example 2). After crosslinking is finished, the modulus E′ value remains relatively constant with still increasing temperature. The modulus E′ of the same film without a crosslinker (none crosslinking as in example 2) decreases at higher increasing temperature, due to the free viscous flow of polymeric chains at such higher temperatures.

[0100] It is easy to see in FIG. 1 that for Ex 3 (according to the invention) there is a sharp increase of E′ between 110° C. to 150° C. and for Ex 4(invention) E′ remains higher than E′ for Ex 2 (comparative without effective crosslinking). Evidence of crosslinking (by E′ increase with temperature) is also obtained for comparative example 1 which corresponds to NMA-containing latex polymer (which is not a formol-free solution as the present invention).

Characterization in pigment printing application: conditions and tests methods used

Preparation of Pigmented Paste Formulation

[0101] The pigmented paste formulations are prepared with the aqueous polymer dispersions of the above-cited examples by diluting to a 5% of solids, adding ammonia until pH is comprised between 8.5 and 9.0 and finally thickening the formulation with Lyoprint® (PT-XN/Huntsman) up to the Brookfield viscosity is 18 000 mPa.Math.s. Then, to this formulation is added 3% of blue pigment IMPERON® KB/Dystar.

[0102] Then, the pigment pastes are applied at a speed of 10 m/min with automatic applicator J ZIMMER, on cotton fabric ISO 105 F02, dried at 120° C. for 3 minutes and then cross-linked at 150° C. for 3 minutes.

Crock-Fastness Test

[0103] To and from motion frictions cycles with standard white cotton are done on the pigment printed textile. These frictions are made following 3 kinds of conditioning of white cotton samples.

[0104] dry cotton: 10 cycles

[0105] water cotton: 10 cycles

[0106] ethanol cotton: 50 cycles

[0107] After drying, we evaluate the white cottons discoloration with a standard grey scale (ref: ISO 105-A03), all measurements are done with a spectrophotometer measuring L*a*b.

[0108] The results are reported in a scale from 1 to 5, where 5 is the best and 1 is the worst.

Domestic Washing Resistance Following NF G 07 093-6 Standard

[0109] The test is carried out by using a washing solution, composed by 4 g of detergent (ECE without optical brightener) per liter of water, with pH adjusted at 10.5 with sodium carbonate and adding to it just before the test 1 g/l of sodium perborate.

[0110] The test is carried out on specimens of printed textile (10 cm×4 cm) made by sewing the cotton printed sheets between two control materials (cotton and viscose) of the proper dimensions.

[0111] The 500 ml capsule used for the washing machine MATIS are filled with 50 ml of washing solution, 25 stainless steel balls (6 mm of diameter) and the specimens with the control materials.

[0112] The washing is carried out at a temperature of 60° Q for 30 min at rotation speed of 40 rpm.

[0113] After the first washing cycle, the specimens are dried and the color is measured with the spectrophotometer. After the first cycle, 4 additional cycles are carried out on the same specimen without any intermediate drying.

[0114] The results are expressed in “delta E” in comparison with initial values by L*a*b* measurements after the first and 5.sup.th washings cycles.

[0115] Lower is the value of “delta E” better is the result, meaning a lower discoloration during the washing test, meaning improved resistance to washing.

Softness

[0116] The softness test is carried out by evaluating the softness of the fabrics prepared with the same amount of pigmented paste and dried with the same applicative conditions.

[0117] The assessment of softness is returned by a personal judgment by taking printed tissues between fingers and determining by touching the softer ones.