GB803014A - Transparent polyester resin-bonded glass fibre material - Google Patents

Abstract

Transparent plastic material is produced by a process comprising embodying a mass of glass fibre in an uncured resin and curing, wherein the resin is derived from a mixture of (a) the reaction product of a dihydric alcohol with an unsaturated dicarboxylic acid or an ester-forming derivative thereof and (b) a copolymerizable monomeric component comprising styrene, and wherein the uncured resin has a refractive index less than that of the glass by an amount in the range 0.019 to 0.025. The resin may be derived from the usual constituents and optionally may be modified with conventional ingredients. In the examples, 10 mols. maleic anhydride and 11 mols, dipropylene glycol are slowly heated under nitrogen to 200 DEG C. and maintained at this temperature for 3 hours, cooled to 80 DEG C. and dissolved in styrene monomer to give a viscosity of 200 cp. at 25 DEG C., 300 parts per million t-butyl catechol being added, resulting in resin A. Resin B of the same viscosity is similarly prepared from 5 mols. maleic anhydride, 5 mols. phthalic anhydride, and 11 mols. propylene glycol. 2 parts by weight of resin B and 1 part by weight of resin A catalysed with benzoyl peroxide is poured on to a regenerated cellulose sheet and a glass fibre mat of refractive index 1.549 is placed on it, and after soaking, more resin is poured on to the mat when it is then covered with a second regenerated cellulose sheet, rolled to remove air and pressed to one-sixteenth inch at 220 DEG F., producing a sheet with a transparency of 55 per cent. A single resin employing the same proportions of acid anhydrides and glycols manufactured in a similar manner produces a sheet with a transparency of 42 per cent. The products may also be formed into articles such as bows, arrows and fishing rods.