GB577432A - A process for the production of bubble-free bodies from synthetic materials - Google Patents

Abstract

Producing bubble-free structures by wetting high molecular polymerization or condensation products with a minimum (e.g. 5 to 15 per cent) of low molecular materials capable of being polymerized or condensed, and wherein the materials in the wetted condition are immediately compressed to expel the air, and the resultant mass is converted into a solid form by polymerizing or condensing the low molecular materials. The high and/or low molecular materials may be loaded with fillers, e.g. carbon black, or colouring materials or softening agents. In the examples: (1) polymethyl methacrylate is wetted with methyl methacrylate containing benzoyl peroxide, compressed in a mould and polymerized; (2) polymethyl methacrylate is sprayed with a dilute solution of benzoyl peroxide, dried, mixed with methyl methacrylate and treated as in (1), the methyl methacrylate may have been stabilised with divalent products; (3) as in (1) or (2), using instead of methyl methacrylate, partially polymerized methyl methacrylate which may be stabilised with hydroquinone; (4) phenolformaldehyde resin is wetted with the pre-condensed products and treated as in (2). An accelerator, e.g. solutions of hydrochloric acid gas in glycerine is added; (5) phenol resins are wetted with solutions of hexamethylene tetramine in phenol (particularly mixtures of meta-and para-cresol) and treated as in (4); and (6) thin plates of aminoplast are wetted with vinyl acetate or with a methacrylic ester compressed and polymerized into a solid block by heating.