Patent GB-1329993-A (GB)
Title: Moulding compositions
IPC: C08L33/04
Filed: 1970-09-16
Abstract: 1329993 Polymer moulding compositions ROHM & HAAS CO 16 Sept 1970 [6 Oct 1969] 44277/70 Heading C3P A moulding composition comprises (a) a rigid thermoplastic polymer containing (i) from 50- 100% by weight, based on the weight of the polymer, of polymerized methyl methacrylate, (ii) 0-50% of units derived from one or more of the following: alkyl methacrylates (other than methyl) aryl methacrylates, alkyl and aryl acrylates, substituted alkyl and aryl acrylates and methacrylates and alkyl- and aryl-substituted acrylamides, the term " alkyl " including " cycloalkyl ", and the term " aryl " including " alkaryl " and aralkyl", and (iii) 0-10% of units derived from one or more of the following: acrylonitrile, methacrylonitrile, styrene, substituted styrene, a vinyl ester, ether, amide, ketone or halide, a vinylidene halide or an olefin: and (b) an elastomeric modifier being a multistage polymer comprising a first stage obtained by polymerizing 30-80 parts by weight based on the total monomer charge for that stage of a C 1-8  alkyl acrylate, 5-20 parts of another copolymerizable monoethylenically unsaturated monomer and up to 5 parts of a copolymerizable polyethylenically unsaturated monomer thereby to obtain a first stage elastomeric polymer having a glass transition temperature less than 10‹ C., and a final stage obtained by polymerizing in contact with the polymer product of the preceding stage or stages from 10-100 parts per 100 parts of elastomer of a monomer mixture containing at least 50% by weight, based on the weight of the mixture, of methyl methacylate, 0-50% of one or more alkyl or aryl acrylates or methacrylates other than methyl methacrylate, and 0-20% of one or more other copolymerizable ethylenically unsaturated comonomers, said final stage having a glass transition temperature of greater than 25‹ C.; the relative amounts of (a) and (b) being such that the composition contains 0À5 to 4À5% by weight, based on the total composition, of the first stage polymer of component (b). Component (b) may comprise at least one intermediate stage polymer derived from one or more of the following: styrene, a substituted styrene, one or more acrylate esters or one or more methacrylate esters, formed in situ on the first stage polymer before formation of the final stage polymer. The polyethylenically unsaturated comonomer component of the first stage of (b) may be 1,3- butylene diacrylate or dimethacrylate or trimethylol propane trimethacrylate. The modifier (b) may be incorporated into component (a) in the form of particles or as an emulsion, suspension or solution in water or an organic compound. Components (a) and (b) may be prepared in the same emulsion or suspension by preparing (a) or (b) and then polymerizing the monomer mix for the other component in the presence of the preformed polymer. The composition may also comprise chain transfer agents, stabilizers, lubricants and colorants. In Examples 1 to 5 component (b) is prepared by copolymerizing butyl acrylate, styrene and butylene diacrylate to form the first stage, and forming thereon a rigid polymethyl methacrylate final stage. In Example 6 the final stage is replaced by a copolymer of methyl methyl methacrylate (30 parts) and 1,3-butylene dimethacrylate (0À3 part). In Examples 7 and 8, the first and final stages are as in Examples 1 to 5, and component (b) also comprises an intermediate stage formed from (i) butyl acrylate, tbutylstyrene and divinyl benzene, (ii) butyl acrylate, vinyl toluene and divinyl benzene, (iii) butyl acrylate, t-butylstyrene and 1,3- butylene dimethacrylate or (iv) butyl acrylate, vinyltoluene and 1,3-butylene dimethacrylate. In Examples 9A to 9L, component (a) formed from (i) methyl methacrylate (96%) and ethyl acrylate (4%) or (ii) 99 to 85% methyl methacrylate and 1 to 15% ethyl acrylate, methyl acrylate or n-butyl acrylate, is prepared in the presence of the products of each of Examples 1 to 8.