Surface sizing of cellulose based products
First Claim
1. A method of surface sizing cellulose based products in order to increase resistance to penetration by aqueous liquids which comprises applying to the surface of said products a sizing composition which comprises an aqueous dispersion of a copolymer obtained by free-radical emulsion polymerization of a monomer mixture comprising(a) from 70 to 99% by weight of(a1) at least one monomer selected from the group consisting of styrene and derivatives thereof;
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wherein the monomer of (a1) comprises at least 50% by weight of (a); and
(b) from 0.5 to 15% by weight of at least one monomer selected from the group consisting of ethylenically unsaturated carboxylic acids and salts thereof, and ethylenically unsaturated sulfonic acids and salts thereof; and
(c) from 0.5 to 15% by weight of other ethylenically unsaturated copolymerizable monomers comprising at least one monomer containing a hydroxyl group, wherein the sum of the percentages of (a)+(b)+(c) is 100, wherein said polymerization is conducted in the absence of a protective colloid effective amount of starch.
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Abstract
The invention relates to a method of surface sizing cellulose based products such as paper, board and paper board. The method comprises applying to the surface of said products an aqueous dispersion of a copolymer obtainable by free-radical emulsion polymerization of a monomers mixture comprising at least one monomer selected from the group consisting of styrene and derivatives thereof; at least one monomer selected from the group consisting of esters of ethylenically unsaturated carboxylic acids and alkanols; and at least one monomer selected from the group consisting of ethylenically unsaturated carboxylic and sulfonic acids and salt thereof; optionally in combination with other ethylenically unsaturated copolymerizable monomers.
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Citations
20 Claims
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1. A method of surface sizing cellulose based products in order to increase resistance to penetration by aqueous liquids which comprises applying to the surface of said products a sizing composition which comprises an aqueous dispersion of a copolymer obtained by free-radical emulsion polymerization of a monomer mixture comprising
(a) from 70 to 99% by weight of (a1) at least one monomer selected from the group consisting of styrene and derivatives thereof; - and
(a2) at least one monomer selected from the group consisting of esters of ethylenically unsaturated carboxylic acids and alkanols;
wherein the monomer of (a1) comprises at least 50% by weight of (a); and(b) from 0.5 to 15% by weight of at least one monomer selected from the group consisting of ethylenically unsaturated carboxylic acids and salts thereof, and ethylenically unsaturated sulfonic acids and salts thereof; and (c) from 0.5 to 15% by weight of other ethylenically unsaturated copolymerizable monomers comprising at least one monomer containing a hydroxyl group, wherein the sum of the percentages of (a)+(b)+(c) is 100, wherein said polymerization is conducted in the absence of a protective colloid effective amount of starch. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method of surface sizing cellulose-based products which comprises applying to the surface of said products by means of a size press a sizing composition comprising an aqueous dispersion of a copolymer obtained by free-radical emulsion polymerization of a monomer mixture containing
(a) from 80 to 99% by weight of (a1) at least one monomer selected from the group consisting of styrene and derivatives thereof, and (a2) at least one monomer selected from the group consisting of esters of ethylenically unsaturated carboxylic acids and alkanols, where the monomer of group (a1) constitutes at least 50% by weight of the monomers of group (a); - the weight ratio of (a1) to (a2) being from about 4;
1 to 2;
1;(b) from 0.5 to 10% by weight of at least one monomer selected from the group consisting of ethylenically unsaturated carboxylic acids and salts thereof, and ethenically unsaturated sulfonic acids and salts thereof; and (c) from 0.5 to 10% by weight of other ethylenically unsaturated copolymerizable monomers comprising at least one monomer containing a hydroxyl group;
the sum of percentages of (a)+(b)+(c) being 100. - View Dependent Claims (12, 13, 14)
- the weight ratio of (a1) to (a2) being from about 4;
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15. A method of surface sizing cellulose-based products which comprises applying to the surface of said products a sizing composition comprising an aqueous dispersion of a copolymer obtained by free-radical emulsion polymerization of a monomer mixture containing
(a) from 80 to 99% by weight of (a1) at least one monomer selected from the group consisting of styrene and derivatives thereof, and (a2) at least one monomer selected from the group consisting of esters of ethylenically unsaturated carboxylic acids and alkanols; -
(b) from 0.5 to 10% by weight of at least one monomer selected from the group consisting of ethylenically unsaturated carboxylic acids and salts thereof; and
ethylenically unsaturated sulfonic acids and salts thereof, and(c) from 0.5 to 10% by weight of other ethylenically unsaturated copolymerizable monomers comprising at least one monomer selected from the group consisting of hydroxyalkyl acrylates and hydroxalkyl methacrylates;
the sum of percentages of (a)+(b)+(c) being 100. - View Dependent Claims (16, 17, 18, 19, 20)
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Specification