Adhésifs à base de polymères

摘要

Adhesives for bonding cellulose ester or ether films to printed surfaces (see Group VIII) contain vinyl acetate/dibutyl maleate co-polymers, the co-polymers containing 35%-50% by weight of combined vinyl acetate. Cellulose compounds specified are the acetate, propionate, butyrate, acetate/propionate, acetate/butyrate, and nitrate, and ethyl cellulose. Printed surfaces specified are Al foil, rubber hydrochloride, polythene, and cellulose or regenerated cellulose surfaces which are not formed by numerous independently movable elements of surface, i.e. including paper and cardboard, but excluding textile fabrics. Dibutyl maleates specified are n-butyl and iso-butyl. The co-polymers are preferably prepared by bulk polymerization initiated by a free-radical catalyst that is soluble in the monomer mixture (e.g. benzoyl or lauryol peroxides and azo-bis-iso-butyronitrile); after at least 75% by weight of the monomer mixture has polymerized, a solvent which is an alcohol or ester boiling below 100 DEG C., but which is not a solvent nor a swelling agent for the cellulose ester or ether, is mixed with the polymer to form a solution; additional catalyst may be added with the solvent, and the solution may be further polymerized. Optionally the pre-formed co-polymer may be present in the original reaction mixture. Solvents specified are ethyl alcohol, isopropyl alcohol, and isopropyl acetate. The final polymer solutions may also contain plasticizers for the cellulose esters or ethers, e.g. triphenyl phosphate, di-ethyl phthalate, dimethoxyethyl phthalate, chlorinated diphenyl, tri-(2-chloroethyl) phosphate, and various specified mixtures thereof. The Provisional Specification is wider in scope and refers to the following additional factors:-(1) Copolymers of vinyl acetate with di-butyl fumarates, itaconates, citraconates, and mesaconates and with butyl crotonates; (2) Catalysts: acetyl peroxide and peracetic acid; (3) Solution polymerization in benzene, cyclohexane or toluene, including the addition of further quantities of benzoyl peroxide and benzene; (4) Solvents for the polymers: ethyl acetate, methanol and methyl ethyl ketone; (5) Plasticizers: dibutyl phthalate, di(methyl cyclohexyl) phthalate and triethyleneglycol di-2-ethyl butyrate; (6) The cellulose surfaces may be in the form of fabrics, fibres or yarns; (7) The surfaces need not be printed; (8) Any of these materials may be bonded to wood, glass, metals or a variety of synthetic polymers.