Patent GB-1086070-A (GB)
Title: Method for preparing foamed solid polymers and product thereof
IPC: C08G18/62
Filed: 1964-09-16
Abstract: A method for the production of foamed polymers comprises heating a feedstock to a temperature of 50 DEG  C. to 350 DEG  C. to liberate tertiary olefin gas and provide hydroxyalkyl groups by decomposition of tertiary alkoxyalkyl groups, holding said feedstock at a temperature sufficient to provide a viscosity suitable for foaming at a pressure sufficient to allow expansion of the teriary olefin gas to form a polymer foam, and reacting said hydroxy-alkyl groups to cross-link polymer molecules of a polymer having a molecular weight of at least abot 500, said feedstock comprising a polymer having cross-linking sites and said feedstock containing tertiaryalkoxyalkyl radicals of the type -(R1O)x-R2 wherein R1 is a divalent aliphatic hydrocarbon radical of 2 to 12 carbon atoms, R2 is a tertiary alkyl radical of 4 to 10 carbon atoms and x is a number from 1 to 25.  The feedstock may comprise an addition or condensation type polymer and the tertiary alkoxyalkyl groups are preferably on the polymer but may be provided by other compounds. Suitable addition polymers are vinyl type polymers containing 1 to 100% of the residue of the ter.-alkoxyalkyl esters derived from unsaturated carboxylic acids, particularly copolymers of styrene or other olefinic compound with alkoxyalkyl esters of maleic or other unsaturated poly- or mono-carboxylic acid, as well as homopolymers such as poly-(tert.-butoxyethyl methacrylate).  Many are described and preparations are given.  In examples, (1) ter.-butoxyethyl methacrylate is homopolymerized in benzene using azobisisobutyronitrile as catalyst; (2) styrene and 2-tert.-butoxyethyl methacrylate is copolymerized in water containing sodium lauryl sulphate, gelatin, sodium sulphate, stearic acid and benzoyl peroxide; (3) styrene and tert.-butoxyethyl acrylate are copolymerized in water containing tricalcium phosphate, sodium dodecyl benzene sulphonate and benzoyl peroxide; (4)-(6) styrene was copolymerized with bis(2-tert.-butoxyethyl) maleate using benzoyl peroxide or azobisisobutyronitrile as catalyst or in water as in (2) above; (7) styrene and maleic anhydride was copolymerized in cumene using dicumyl peroxide as catalyst and then esterified with tert.-butoxyethanol; (8) and (10) styrene was copolymerized with bis-(2-tert.-butoxyethyl) itaconate in benzene using azobisisobutyronitrile or in bulk using benzoyl peroxide as catalyst; (ii) vinyl acetate and bis-(2-tert.-butoxyethyl) maleate was copolymerized in water containing sodium dodecyl sulphate, sodium phosphate and azobisisobutyronitrile); and (12) vinyl chloride and bis(2-tert.-butoxyethyl) maleate was copolymerized as in (11).  The preferred condensation type polymers are polyesters and Example 13 describes the reaction of mono-tert.-butyl ether of glycerine with dimethyl terephthalate to give a viscous polyester which is then heated with titanium tetrachloride to produce a rigid cross-linked foam.  Cross-linking of the polymers may be effected with the aid of organic or inorganic polyfunctional compounds, e.g. acids, diisocyanates, formaldehyde and its resinous condensates, silicon compounds, epoxy resins and metal compounds, e.g. pyromellitic dianhydride and/or stannous oxalate; TiCl4; PCl3; sodium bisulphate, toluene diisocyanate and hexahydromethyl aniline; diphenyl-dichlorosilane; and phosphotungstic acid.  Foaming may be assisted by the presence of additional blowing agents of conventional type.  The polymers may be formed into films.ALSO:2-Tertiary-butoxyethanol is prepared by reacting isobutylene with ethylene glycol in the presence of sulphonated polystyrene-divinyl benzene catalyst (Example 1). Bis(2-tertiary-butoxyethyl)itaconate is prepared from tertiary-butoxy ethanol and di-methyl itaconate using tetraisopropyl titanate as catalyst (Example X).