Crosslinkable aqueous polymer dispersions with aminoacid crosslinker for textile

1 . An aqueous coating composition comprising:

a) an aqueous polymer dispersion, 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, 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 vinylinic monomers, with the exception of (meth)acrylic acid monomers, and

a2) at least one ethylenically unsaturated monomer different from a1) 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%; and

b) a crosslinker selected from amino acids bearing at least two amino functional groups capable of reacting with said carboxylic acid functional groups,

where a molar ratio of the amino groups of said crosslinker b) to the carboxy groups of said polymer of dispersion a) is of from 0.1 to 3.0.

2 . The aqueous coating composition according to claim 1 , 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, tetrahydrophthalic acid and anhydride (cis 4-cyclohexene, 1,2-dicarboxylic acid and anhydride).

3 . The aqueous coating composition according to claim 1 , wherein said monomer a2) is itaconic acid or anhydride.

4 . The aqueous coating composition according to claim 1 , 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 monomer, vinyl acetate, vinyl fumarate, styrene, acrylonitrile, unsaturated silane, maleate, and butadiene.

5 . The aqueous coating composition according to claim 1 , where the molar ratio of the amino groups of said crosslinker b) to the carboxy groups of said polymer of dispersion a) is from 0.1 to 2.0.

6 . 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).

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

8 . 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 the aqueous coating composition by 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.

9 . A coated or treated flexible porous substrate, resulting from the method defined according to claim 8 .

10 . A coated or treated flexible substrate of claim 9 , selected from woven and non-woven fibers, fabrics, textile, paper, cardboard and glass fibers.

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

12 . The aqueous coating composition according to claim 1 , wherein said coating composition is free of any added catalyst (0%) for the reaction between said amino groups of said crosslinker and said carboxy group of said polymer and able to cure at a pH range lower than 6.

13 . The aqueous coating composition according to claim 1 , wherein the at least one ethylenically unsaturated monomer a2) is present at a weight content with respect to the total weight of said copolymer of from 0.2% to 10%.

14 . The aqueous coating composition according to claim 1 , wherein at least one of said carboxy groups of polymer a) reacts with at least one of said amino groups of said crosslinker b).

15 . The aqueous coating composition according to claim 1 , wherein said polymer a) is crosslinked by said crosslinker b) at a temperature in the range of from 100° C. to 230° C.