Patent GB-1009486-A (GB)
Title: Improvements in or relating to synthetic polymer latices
IPC: C09D151/00
Filed: 1964-08-26
Abstract: Aqueous latices of composite polymer particles having a core comprising polyvinylidene chloride or a copolymer of vinylidene chloride with an ester of an a -unsaturated aliphatic acid and one or more successive layers comprising a copolymer of vinylidene chloride with an ester of an a -unsaturated aliphatic acid enveloping said core, the copolymer of the outer layer being a copolymer of vinylidene chloride with an ester of an a -unsaturated aliphatic acid other than an alkacrylic acid and the ester content of the copolymer of the outer layer being greater than that of the copolymer of the core, may be prepared by polymerizing vinylidene chloride, optionally together with said ester, in aqueous emulsion to form homogeneous core particles, and introducing and copolymerizing additional vinylidene chloride and ester, the proportion of vinylidene chloride in the monomers employed to form the outer layer being less than that in the monomers employed to form the core particles.  Specified esters are alkyl, benzyl and tolyl esters of acrylic, methacrylic, itaconic, fumaric, maleic, crotonic and citraconic acids. Polymerization may be effected in the presence of initiators, e.g. redox systems of hydrogen peroxide or t.-butyl hydroperoxide with ascorbic acid, erythorbic, alkali metal bisulphites or formaldehyde sulphoxylates; and emulsifiers, e.g. sodium lauryl or alkylaryl polyether sulphates, and isooctylphenyl, nonylphenyl, ethylphenyl or tridecyl polyethylene glycol ethers.  Examples describe the preparation of latices using hydrogen peroxide, ascorbic acid, sodium lauryl sulphate together with (1) (a) core vinylidene chloride, 1st layer vinylidene chloride, 2-ethylhexyl acrylate and methyl methacrylate, 2nd layer vinylidene chloride and ethyl acrylate; (1) (b) core vinylidene chloride and methacrylic acid, 1st layer vinylidene chloride, methacrylic acid, 2-ethylhexyl acrylate and methylmethacrylate, and 2nd layer vinylidene chloride and ethylacrylate; and (2) core vinylidene chloride and methyl methacrylate, 1st layer vinylidene chloride and ethyl acrylate, and 2nd layer vinylidene chloride and ethyl acrylate; and (3) core vinylidene chloride, 1st layer vinylidene chloride and dibutylitaconate, and 2nd layer vinylidene chloride, ethyl acrylate and dibutyl itaconate.  The latices may be used to give nonblocking coatings on paper, regenerated cellulose films and synthetic resin films.ALSO:Substrates such as paper, regenerated cellulose film or films of polyolefins, poleysters, polyamides, plasticized polyvinyl chloride, polyvinylidene chloride, polyethyl acrylate or copolymers of vinyl chloride or vinylidene chloride, may be coated with aqueous latices of composite polymer particles having a core comprising polyvinylidene chloride or a copolymer of vinylidene chloride with an ester of an a -unsaturated aliphatic acid and one or more successive layers comprising a copolymer of vinylidene chloride with an ester of an a -unsaturated aliphatic acid enveloping said core, the copolymer of the outer layer being a copolymer of vinylidene chloride with an ester of an a -unsaturated aliphatic acid other than an alkacylic acid, and having an ester content greater than that of the core.  In examples, paper is coated with aqueous latices in which the polymer particles are derived from the following monomers: (1) (a) core vinylidene chloride, first layer vinylidene chloride, 2-ethylhexyl acrylate and methyl methacrylate, second layer vinylidene chloride and ethyl acrylate; (1) (b) core vinylidene chloride and methacrylic acid, first layer vinylidene chloride, methacrylic acid, 2-ethylhexyl acrylate and methyl methremoved at run-off 26 by a paddle 28 whilst acrylate, second layer vinylidene chloride and ethyl acrylate; (2) core vinylidene chloride and methyl methacrylate, first and second layers vinylidene chloride and ethyl arcylate; and (3) core vinylidene chloride, first layer vinylidene chloride and dibutyl itaconate, and second layer vinylidene chloride, ethyl acrylate and dibutyl itaconate.