| 摘要 |
<p>An aqueous dispersion comprises polymeric particles, each particle having a core portion and a coating on the core portion, the core portion constituting from 60 to 90% by weight of the two portions and comprising essentially a copolymer of: 88-96% vinylidene chloride; 2 to 9% of a C1-C3 alkyl acrylate; and 1 to 10% of acrylic acid-all percentages by weight based on total monomer; and the coating portion constituting from 10 to 40% by weight of the two portions and comprising essentially a copolymer of: 60-88% vinylidene chloride; 11-39% acrylonitrile or a C1-C3 alkyl acrylate or methacrylate; and 1-10% acrylic or methacrylic acid-all percentages by weight based on total monomer. The dispersion is made by polymerizing a monomeric composition corresponding to the core portion in aqueous dispersion, then adding monomer material and initiator to correspond to the coating portion and polymerizing further. The compositions may contain wax.ALSO:Films, especially of polypropylene, are coated with an aqueous dispersion comprising polymer particles, each particle having a core portion and a coating on the core portion, the core portion constituting from 60 to 90% of the two portions by weight and comprising essentially a copolymer of vinylidene chloride 88-96%, C1-C3 alkyl acrylate 2-9%; and acrylic acid 1-10% by wt.; and the coating portion constituting from 40 to 10% of the two portions by weight and comprising essentially a copolymer of vinylidene chloride 60-88%, acrylonitrile or a C1-C3 alkyl acrylate or methacrylate 11-39%, and acrylic or methacrylic acid 1-10% by weight. The compositions may contain wax. The polypropylene film may be given a prior flame treatment or oriented. Other films specified are polyethylene, polyethylene terephthalate, polyvinyl chloride, and polyvinyl fluoride films.</p> |
