WATER-BASED COATING COMPOSITION Russian patent published in 2020 - IPC C09D127/08 C09D5/08 C08K5/32 

FIELD: chemistry.

SUBSTANCE: present invention relates to an aqueous coating composition and methods used to produce protective coatings on substrates and especially on metal-containing substrates. Aqueous composition contains: an aqueous latex of a copolymer consisting essentially of repeating units obtained from (i) vinylidene chloride, (ii) vinyl chloride, (iii) one or more alkyl(meth)acrylate having 1 to 12 carbon atoms in the alkyl group, and (iv) one or more aliphatic alpha-beta-unsaturated carboxylic acids, which repeating units share is at least 1.0 wt % based on total weight of copolymer; and, at least, one anticorrosive pigment, containing aluminum salt of (poly)phosphoric acid, modified with alkali-earth metal oxide; at least one nonionic surfactant; and, at least, one inorganic filler, different from pigment, in such amount that total volume concentration of pigment, covering pigment and filler, is from 20 to 40 vol % when determining based on dried composition coating. At that, said copolymer is stable with respect to dehydrochlorination, so that total chloride content in solid residue of aqueous latex after heat treatment at approximately 120 °C for 2 hours is less than 1000 ppm based on the total weight of the copolymer, as well as ratio (j) of crystallinity index of said copolymer (CI (CI)) after heat treatment, including heating at 60 °C for 48 hours, to (jj) its crystallinity index before such thermal treatment (IR_{(after heat treatment)}/IR_{(before heat treatment}) is less than 1.15.

EFFECT: invention provides formation of coatings, critical thickness of one layer of coating film of which is sufficient to achieve coating thickness of 300 mcm or more in the absence of shrinkage cracks.

15 cl, 3 ex