Patent GB-613506-A (GB)
Title: Improvements in or relating to the shaping of sheets of polymerised unsaturated esters of polybasic acids
IPC: B29C39/00
Filed: 1944-04-26
Abstract: A sheet of hard polymer of a polyester containing at least two unsaturated groups and formed from a polybasic acid and an a - or b -unsaturated monohydric alcohol, and containing at least 85 per cent of acetone insoluble polymer, is heated to a temperature above 50 DEG C. shaped without exceeding its elastic limit and cooled before removing the shaping forces.  Plasticizers such as halogenated naphthalene, diethylene glycol bis-(butyl carbonate), dibutyl phthalate, halogenated diphenyl or polymerized methyl methacrylate, vinyl acetate, vinylidene chloride, vinyl chloride or styrene may be incorporated in the polymeric sheets which are preferably prepared by cast polymerization by heat or light in presence of 1-3 per cent of benzoyl peroxide or other per-compound.  Polymerization may take place as described in Specification 7841/44 (as open to inspection under Sect. 91). Suitable alcohols mentioned for the polymers are allyl, methallyl, isopropenyl, vinyl, 2-chloroallyl, butadienyl, a - or b -ethylallyl, b -dimethylallyl, crotyl, propargyl, methyl propargyl, phenyl propargyl, cinnamyl or linalyl alcohol or methyl or ethyl vinyl carbinol.  Among suitable polybasic acids mentioned are oxalic, phthalic, succinic, maleic, fumaric, itaconic, adipic, citric, tartaric, tricarballylic, diglycollic, dilactic, boric, silicic, titanic, phosphoric, stannic, or sulphuric acid, glycolyl acid malonate, ethylene glycol bis-acid phthalate, ethylene glycol bis-acid carbonate, the compound <FORM:0613506/IV(a)/1> , compounds such as <FORM:0613506/IV(a)/2> or <FORM:0613506/IV(a)/3> or <FORM:0613506/IV(a)/4> or other acids described in Specifications 575,386, 576,083 and 595,056.  When the polybasic acid is unsaturated, it may be esterified with both a saturated and an unsaturated alcohol as in allyl ethyl maleate; allyl stearyl maleate; allyl lauryl fumarate. Examples describe the polymerization at 70 DEG C. between parallel glass sheets of mixtures of benzoyl peroxide with diethylene glycol bis-(allyl carbonate); diallyl phthalate; ethylene glycol bis-(allyl carbonate); and diallyl succinate.  The formed sheets consisting of polymers, more than 85 per cent of which were insoluble in acetone, were shaped while at temperatures ranging from 100-165 DEG  C. and held in the shaped position until cool. They retained their shape when the deforming forces were removed. Specifications 5048/44, as open to inspection under Sect. 91, also is referred to.ALSO:Sheets of a hard polymer of a polyester containing at least two unsaturated groups and formed from a polybasic acid and an a  or b  unsaturated monohydic alcohol and containing at least 85 per cent. of acetone insoluble polymer [see Group IV] are heated to a temperature above 50 deg. C., shaped without exceeding their elastic limit and cooled before removing the shaping forces.  At room temperature the shaped sheets show little tendency to elastic recovery.  Tests described in the Specification illustrate the behaviour under stress and after release of the stress of these polymers as compared with polymethyl methacrylate.  Examples describe the shaping of sheets prepared by polymerising between parallel glass sheets mixtures of benzoyl peroxide and ethylene glycol bis (allyl carbonate), diethylene glycol bis (allyl carbonate); diallyl phthalate; and diallyl succinate.  The sheets are heated to temperatures ranging from 100-165 deg. C., bent and cooled in the bent position.  Many other polymers are mentioned as being suitable for the invention.