Patent GB-1056824-A (GB)
Title: Polymer compositions for coating paper
IPC: D21H19/58
Filed: 1963-10-24
Abstract: Compositions for coating paper comprise an aqueous polymer dispersion, one or more pigments starch and/or casein, and optionally other additives, said dispersion containing: (i) a copolymer of 40 to 70 parts by weight of styrene, 3 to 60 parts by weight of at least one ester of acrylic acid with an alcohol having 2 to 12 carbon atoms and 0.5 to 5 parts by weight of methacrylamide; and (ii) an emulsifier mixture comprising (a) a sulphated reaction product of 1 mole of at least one (C6- 20-alkyl)-pheno with at least 9 moles of ethylene oxide and/or propylene oxide; and (b) at least one emulsifier which is a reaction product of 1 mole of a compound containing a hydroxyl, carboxyl or amide group with at least 10 moles of ethylene oxide. Suitable as emulsifiers (b) are ethoxylated fatty acids or amides or ethoxylated alcohols having at least 10 carbon atoms in the acid, amide or alcohol moiety, and also ethoxylated alkylphenols. As pigments there are specified kaolin, china clay, barium sulphate, calcium carbonate and titanium dioxide.  Pigment dispersing agents may also be present e.g. polyacrylic acid salts, maleic acid copolymer salts (e.g. copolymers with styrene, vinyl ethers and isobutylene), salts of partly esterified maleic acid copolymers and high molecular weight polyphosphates including sodium hexameta phosphate.  Other optional ingredients include optical brighteners, dyes antifroth agents, waxes and plasticizers (al unspecified). In examples, the copolymers used are copolymers of styrene and methacrylamide with ethyl, n-butyl, isobutyl, 2-ethylhexyl, dodecyl or isobutyl/2-ethyl hexyl acrylate.  In one example, a sturene-isobutyl acrylate-methacrylamide copolymer dispersion is prepared by emulsion polymerization of the appropriate monomers using potassium persulphate catalyst, part of the monomer emulsion being added during polymerization.ALSO:Paper is coated with a composition which comprises an aqueous polymer dispersion, one or more pigments, starch and/or casein, and optionally other additives, said dispersion containing:- (i) a copolymer of 40 to 70 parts by weight of styrene, 30 to 60 parts by weight of at least one ester of acrylic acid with an alcohol having 2 to 12 carbon atoms and 0.5 to 5 parts by weight of methacrylamide and (ii) an emulsifier mixture comprising (a) a sulphated reaction product of 1 mole of at least one (C6 - 20 alkyl)-phenol with at least 9 moles of ethylene oxide and/or propylene oxide and (b) at least one emulsifier which is a reaction product of 1 mole of a compound containing a hydroxyl, carboxyl or amide group with at least 10 moles of ethylene oxide. Suitable as emulsifiers (b) are ethoxylated fatty acids or amides or ethoxylated alcohols having at least 10 carbon atoms in the acid, amide or alcohol moiety, and also ethoxylated alkylphenols. As pigments there are specified kaolin, china, clay, barium sulphate, calcium carbonate and titanium dioxide.  Pigment dispersing agents may also be present e.g. polyacrylic acid salts, malcic acid copolmer salts, salts of partly esterified malcic acid copolymers and high molecular weight polyphosphates including sodium hexametaphosphate.  Other optional ingredients include optical brighteners, dyes, antifroth agents, waxes and plasticisers (all unspecified).  The compositions are suitable for coating paper with conventional applicator equipment, e.g. roll coaters and doctor blades.