FIELD: pulp industry.
SUBSTANCE: group of inventions relates to gluing paper and cardboard, in particular to cationic aqueous polymer dispersions for surface gluing of paper and cardboard. Aqueous polymer dispersion (A) is obtained via free-radical emulsion copolymerisation of a first mixture of ethylenically unsaturated monomers, containing: (a) from 5 to 45 wt % styrene and (b) from 55 to 95 wt % of at least one C1-C4-alkyl methacrylate or acrylate, where sum (a)+(b) is 100 %, in presence of water-soluble redox system, containing first free-radical initiator for free radical emulsion copolymerisation, and aqueous composition (B) of prepolymer, obtained by free-radical emulsion copolymerisation in a polymerisation solvent comprising C1-C6-carboxylic acid and an anhydride of C1-C6-carboxylic acid, a second mixture of ethylenically unsaturated monomers, comprising: (i) from 15 to 30 wt % of at least one ethylenically unsaturated quaternary amine, selected from quaternary salt of N, N, N-tri(C1-C4-alkyl)amino-C1-C4-alkyl methacrylate with mineral acid, (ii) from 0 to 10 wt % ethylenically unsaturated tertiary amine, selected from dimethylaminoethylmethacrylate, (iii) from 60 to 80 wt % styrene, where sum (i)+(ii)+(iii) is 100 %, wherein amount (ii) does not exceed amount (i), in the presence of a second free-radical initiator, and adding water to the obtained polymer dispersion to obtain an aqueous prepolymer composition, where component (b) is tert-butyl acrylate and/or tert-butyl methacrylate. Described also is a method of producing an aqueous polymer dispersion, a sizing composition for surface gluing a cellulose product, a cellulose product with a glued surface, a method for surface gluing of a cellulose product, in particular paper or cardboard, use of a sizing composition or an aqueous polymer dispersion for surface gluing of a cellulose product.
EFFECT: technical result is providing a finely dispersed aqueous polymer dispersion, which provides an effective surface gluing of the cellulose product, in particular a cellulose product containing recycled fiber.
19 cl, 1 tbl, 1 dwg, 8 ex
