aqueous vinylidene chloride - copolymers - dispersion for the production of coating layers on films made from regenerated cellulose hydrate and method for the preparation of the coating layers

摘要

An aqueous dispersion of a vinylidene chloride copolymer contains a phenoplast and/or aminoplast in such an amount per 100 parts by weight of copolymer as results from 0.01-0.1 part of phenol and/or amine when 0.5-5 parts of a phenol and/or amine are precondensed for 15-120 seconds in acid conditions followed by further condensation in alkaline conditions with 10-50 parts of formaldehyde in 100 parts of a mixture of 17-50 parts of water with 83-50 parts of a miscible organic solvent. The only specified copolymer is with butyl acrylate, methyl methacrylate and itaconic acid. The condensation polymer may be obtained from phenol, cresols, bisphenol-A, urea, thiourea, melamine, guanidine or dicyandiamide in a mixture of water and tetrahydrofuran, dimethylsulphoxide, 4 - methylol - 1,3 - dioxan, 4,4-dimethyl - 1,3 - dioxan, 1,4 - dioxan, 1,4-butanediol, isopropanol, ethanol, triglycol, glycerol, glycol or diglycol. The formadlehyde may be added as paraformaldehyde. The solution of condensation polymer obtained is added directly to the copolymer dispersion. The dispersions are used to coat films of regenerated cellulose hydrates.ALSO:Films of regenerated cellulose hydrates are coated with an aqueous dispersion of a vinylidene chloride copolymer also containing phenoplast and/or aminoplast in such an amount per 100 parts by weight of copolymer as results from 0.01 - 0.1 part of phenol and/or amine when 0.5 - 5 parts of an amine and/or phenol are precondensed for 15-120 seconds in acid conditions followed by further condensation in alkaline conditions with 10-50 parts of formaldehyde in a mixture of 17-50 parts of water with 83 - 50 parts of an organic solvent miscible with water in the indicated range (see Division C3). The dispersion is applied by dip or roll coating and excess removed by an air brush or doctor knife. After drying the film is exposed for 0.1-5 seconds to a high frequency field or an infra red radiation such that the film reaches a surface temperature of 120-140 DEG C.