Patent GB-1414187-A (GB)
Title: Thermoformable compositions
IPC: C08L51/00
Filed: 1972-10-30
Abstract: 1414187 Multi-stage graft copolymer-thermoplastic polymer composition ROHM & HAAS CO 30 Oct 1972 [5 Nov 1971] 49869/72 Headings C3P and C3G A composition comprises (1) 10 to 96% of a thermoplastic polymer containing at least 50% of (C 1-4 ) alkyl methacrylates, styrene, substituted styrene, acrylonitrile, substituted acrylonitrile the balance, if any, being other monoethylenically unsaturated monomers, and (2) 90 to 4% of a multi-stage sequentially-produced aqueous emulsion graft polymer having (A) a non-elastomeric first stage polymer having a glass transistion temperature (+g) greater than 25 C. and produced from at least 70% of a monomer as defined in (1) above, 0 to 30% of other mono-ethylenically unsaturated monomer, 0 to 10% of a polyfunctional cross-linking monomer and 0À05 to 5% of a graft-linking monomer (B) an intermediate, elastomeric stage polymer having, alone, a +g below or equal to 25 C., and produced from 50 to 99À9% of butadiene, a substituted butadiene on a (C 1-8 ) alkyl acrylate, 0 to 49À9% of a further monoethylenically unsaturated monomer, 0 to 5% of a polyfunctional cross-linking monomer and 0À05 to 5% of a graft-linking monomer and (C) a final stage polymer having a +g greater than 25 C. and produced from at least one of the monomers specified under (1) above. The compositions may be obtained by simple blending of the dry polymers or their aqueous emulsions or by polymerizing the monomers to form polymer (1) in the presence of preformed (2). Further stages may be included in polymer (2). In the examples, polymers (1) are polymethylmethacrylate, methylmethacrylate / ethylacrylate copolymer, polystyrene, methylmethacrylate/styrene copolymer, styrene/acrylonitrile copolymer, methylmethacrylate/styrene/ acrylonitrile or ethyl acrylate terpolymer, and a methylmethacrylate/ethyl acrylate copolymer, while polymers (2) are prepared from (A) methyl methacrylate, styrene, diallyl maleate, allyl methacrylate, 1,3-butylene-glycol dimethacrylate, acrylonitrile, and alpha methyl styrene, in various combinations thereof (B) butyl-, 2-ethyl hexyl- and isobutyl acrylate, butadiene, allyl methacrylate, diallyl maleate, butylene glycol diacrylate and styrene, in various combinations thereof always including at least one elastomer forming-monomer and at least one of the allyl esters, and (C) methyl methacrylate, styrene, ethyl acrylate, acrylonitrile, and alphamethylstyrene in various combinations thereof. Most of the blends are formed by mixing emulsions of preformed polymers or the dry polymers on a roll mill, but in Examples 19 and 20 methyl methacrylate is polymerized to form polymer (1) in the presence of t-butyl peroxypivalate and azobis-isobutyronitrile and the preformed polymer (2) in bulk between metal sheets and under pressure. Intermediate, further stages exemplified are methyl methacrylate/ allyl methacrylate, styrene/allyl methacrylate// butylacrylate/allyl methacrylate, and methyl methacrylate/styrene or alphamethyl styrene/ allyl methacrylate//butyl acrylate/allyl methacrylate. Comparative examples of two-stage copolymer compositions are given. Numerous preparations of the multi-stage polymers (2) in emulsion with up to 5 stages and up to 4 monomers in each stage are exemplified.