FIELD: technological processes.
SUBSTANCE: invention relates to a heat-sealable system for applying a coating suitable for gluing bases and containing a film-forming dispersion. Dispersion contains only 35% to 60% by weight of a mixture of components A, B and C, and the mixture consists of: 30–40% by weight of a polyester mixture as a type A polymer, from 30 to 40 poly(meth)acrylate or a mixture of two or more poly(meth)acrylates as type B polymer and from 20 to 35 of one or more rubber species containing repeating styrene units as a type C polymer. In each case in terms of total weight of composition of polymers of types A, B and C, wherein components A, B and/or C can also be present completely or to some extent in form of graft copolymers AB or CB. Type C polymer is SEBS-rubber, a maleic anhydride grafted copolymer of SEBS rubber with a maleinic acid content of 1.4 to 2.0% by weight or a copolymer, mainly consisting of styrene and methyl methacrylate. Content of solid substances in the dispersion ranges from 25% to 70% by weight. Type A polymer is a mixture of two polyesters A1 and A2, wherein polyester A1 with number-average molar mass Mn from 2000 to 4000 g/mol is obtained by means of copolycondensation of itaconic acid, and polyester A2 with number-average molar mass Mn from 10,000 to 35,000 g/mol does not contain double bonds, and wherein coating system contains from 5 to 10% by weight of polyester A1 and 25 to 35% by weight of polyester A2 in terms of total weight of composition of polymers of type A, B and C. Described also is method of gluing films based on polyester or film coated with PET, with polystyrene, polyester and polyvinyl chloride, where the coating is dried and the film is placed with the coated side onto the material to be glued, made from polystyrene, polyester or PVC, and performing gluing at temperature of 120 to 220°C and at pressure of 0.1 to 0.6 MPa for period of 0.1 to 1.5 s.
EFFECT: high transparency of heat-sealable coatings, despite using rubber based on styrene-containing polymers, which is optically incompatible with polyesters and polymethacrylate.
8 cl, 9 tbl, 13 ex
