Patent GB-1340025-A (GB)
Title: Thermoplastic compositions
IPC: C08L33/12
Filed: 1971-04-19
Abstract: 1340025 Multi-stage graft polymers ROHM & HAAS CO 19 April 1971 [13 April 1970] 26741/71 Heading C3G A multi-stage sequentially produced polymer comprises (A) a first elastomeric portion polymerized from a monomer mix comprising at least 50% by weight of one or more alkyl or aralkyl acrylates, 0À05-5À0% by weight of one or more cross-linking monomers, 0À05-5À0% by weight of one or more graft-linking monomers having two or more addition polymerizable unsaturated groups which participate in the polymerization reaction at substantially different rates, adapted to attach the elastomeric phase to the rigid phase defined hereinafter, 0-10À0% by weight hydrophilic monomer or non-hydrophilic monomer which is converted to hydrophilic mers in the elastomeric portion, the balance, if any, of said monomer mix being composed of one or more other copolymerizable ethylenically unsaturated monomars; and (B) a final, rigid thermoplastic portion polymerized, in the presence of said elastomeric portion, from a monomer mix comprising at least 50% by weight alkyl methacrylate, wherein said elastomeric portion and said thermoplastic portion have a minimum attachment level as hereinbefore defined of 20%. The multi-stage polymer material may be prepared by emulsion polymerization of an appropriate monomer charge to form the elastomeric portion and then continuing the emulsion polymerization with the addition of the monomer mix constituting the rigid portion material. The polymerization reactions may be initiated by either thermal or redox type initiator systems and conven-  tional emulsifiers may also be present. Numerous examples of all the different monomer units  are given. The composition of the multi-stage polymers in the specific examples (1-6) all of which refer to two-stage polymers is as follows:  (1) a base polymer of butyl acrylate ("acrylate"), 1,3-butylene glycol diacrylate ("crosslinker"), allyl methacrylate ("graft-linker"), and styrene  acrylonitrile, hydroxy ethyl acrylate or methacrylamide units on to which is grafted monomer units of methyl methacrylate ; (2) a base polymer of butyl acrylate, 1,3, butylene glycol diacrylate, allyl methacrylate, styrene  hydroxyethyl acrylate, hydroxyethyl methacrylate or acrylamide on to which is grafted methyl methacrylate  hydroxyethyl methacrylate; (3) a base polymer of butyl i acrylate, 1,3-butylene diacrylate, allyl meth-  acrylate, styrene, and either methacrylamide,  N-ispropyl acrylamide or hydroxy propyl  methacrylate on to which is grafted methyl  methacrylate; and (4), (5), (6) a base polymer of  butyl acrylate, 1,3-butylene glycol diacrylate, allyl methacrylate, styrene, hydroxypropyl methacrylate, ethylthioethyl methacrylate on to which is grafted a mixture of methyl methacrylate and methyl acrylate. Examples (8) and (9) refer to three stage polymers in which the 1st stage is constituted of butyl acrylate, styrene, ethylthioethyl methacrylate, butylene glycol diacrylate and allyl methacrylate; the 2nd stage of styrene, butyl acrylate, divinyl benzene and allyl methacrylate; and the 3rd stage (rigid portion) of either (a) methyl methacrylate, styrene and methyl acrylate or (b) methyl methacrylate, α-methyl styrene and methyl acrylate. The multi-stage polymer may be blended with a rigid thermoplastic polymer such as poly- (methyl methacrylate), copolymer of methyl methacrylate and ethyl acrylate, and vinyl halide homo- or co-polymers. In addition lubricants, dyes, fillers and plasticizers may be incorporated.