Patent GB-639557-A (GB)
Title: The production of sheets and other bodies of polymeric resin
Inventor: TOMPSETT ALAN LESLIE LAWS
IPC: B29C67/00
Filed: 1947-03-12
Abstract: One or more monomeric and/or partially polymerized unsaturated organic compounds, at least the major proportion of which have the CH2=C< grouping, e.g. methyl methacrylate or a -chloroacrylate and styrene, are polymerized in contact with plain or patterned forming surfaces at least one of which has been made by moulding or casting and hardening one or more thermosetting liquids and/or resins against a surface having the desired finish, the surface of the hardened material being free from polymerization inhibitors, e.g. phenol. Sheets are produced in a flat chamber with side walls as forming surfaces which are rigid but capable of relative movement to compensate for shrinkage during polymerization.  The thermosetting liquids, e.g. dimethacrylic esters of low molecular weight dihydroxy ethylene glycol, phthalic acid polyesters, or resins, e.g. urea- and melamine-formaldehyde resins, are preferably filled, e.g. with wood flour, cotton, asbestos, glass or synthetic fibres, or laminated with paper or fabric to reduce shrinkage during hardening.  The forming surfaces may be backed with phenol-formaldehyde resins.  In an example, highly-polished laminated urea-formaldehyde resin sheets are formed into a casting cell with a resilient gasket and partially polymerized methyl methacrylate containing benzoyl peroxide heated therein, first at 40 DEG  C. and then at 100 DEG  C. to form a sheet. Specifications 433,540, 445,927, [Group III], 450,305, 460,239, 460,240, 469,564, 474,242, 475,552, 477,364, [all in Group V], 484,343, 567,777, 567,778, [both in Group XXII], 569,684, 582,559, 612,070, 618,124 and 622,374 are referred to.ALSO:One or more monomeric and/or partially polymerized unsaturated organic compounds e.g. methyl methacrylate or  -chloracrylate and styrene are polymerized in contact with plain or patterned forming surfaces, at least one of which has been made by moulding or casting, and hardening one or more thermosetting liquids and/or resins against a surface having the desired finish.  The surface of the hardened material must be free from polymerization p  inhibitors, e.g. phenol. The liquids, e.g. di-methacrylic esters of low colecular weight dihydroxy ethylene glycol, phthalic acid polyesters, or resins, e.g. urea- and melamine-formaldehyde resins, are preferably filled or laminated with paper or fabric to reduce shrinkage during hardening. The forming surfaces may be backed with phenol-formaldehyde resins. In an example, highly-polished laminated urea-formaldehyde resin sheets are used as side walls, spaced by means of a resilient gasket of a casting cell and partially polymerized methyl methacrylate containing benzoyl peroxide heated therein first at 40 DEG  C. and then at 100 DEG  C. to form a sheet.  Specifications 433,540, [Group IV], 445,927, [Group III], 450,305, [Group IV], 460,239, 460,240, 469,564, 474,242, 475,552, 477,364, 484,343, [Group IV], 5657,777, 567,778 [both in Group XXII], 569,684, 582,559, [both in Group IV], 612,070, [Group IV (a)], 618,124, and 622,374, [Group IV (a)], are referred to.