GB1027264A - Reinforced plastics - Google Patents

Abstract

Moulding compositions are made with glass fibre fabric or other reinforcing elements and a copolymer of acrylinitrile and styrene, substituted styrene, or other mono-olefinic or polyolefinic compound, polymerized with a peroxide catalyst. Substituted styrenes usable are those substituted in the benzene ring by one or more halogens or one or more alkyl groups of not more than 18 C atoms. Other monolefinic compounds include alkyl acrylates and methacrylates, vinylidene chloride, vinyl propionate or stearate, diethyl or dibutyl fumarate, allyl benzoate or hexoate, and vinyl-n-butyl ether. The peroxides include benzoyl peroxide, methyl ethyl ketone peroxide, cumene peroxide, t-butyl per benzoate, hydroperoxide and acetyl peroxide, with or without a promoter such as dimethyl aniline or cobalt naphthenate. The mix may also include polyolefinic compounds such as divinyl-benzene, -naphthalene, -biphenyl, or phenanthrene, or substitution products thereof, or the following -ethylene or butylene dimethacrylate, trimethylol propane trimethacrylate, triallyl cyanurate, diallyl phthalate or fumarate, allyl methacrylate, divinyl adipate or phthalate, these compounds being used preferably in admixture with styrene or its equivalent in the acrylonitrile mix, but when used without the styrene &c. a proportion of 50% or more may be employed without producing brittleness or poor impact properties in the product. A blocked phenol such as 2.6-di-t-butyl-para-cresol may be added as antioxidant, and thickeners such as butadiene-and other conjugated diolefin-acrylonitrile copolymers, polydichlorostyrene and polymethacrylates may be included. Reinforcing materials include glass, asbestos, rock, diatomaceous earth, cotton, linen, sisal, hair, nylon, rayon, polyethylene terephthalate, iron, aluminium and copper, the preferred material being glass fibre in the form of fabric, mat, chopped fibres, rovings, filaments and staple. Glass fibres may be pre-sized with starch-mineral oil mixtures, polyvinyl acetate, polyisobutylene or isobutylene isoprene copolymers, butadiene-styrene copolymers, natural rubber, vinyl- or allyl-halo-silanes and alkyl or aryl silane esters containing vinyl, allyl, methallyl or crotyl substituent groups. Glass fibre mats or fabrics may be impregnated with the above mixes by brushing, spraying, pouring or dipping and laminates formed by curing superposed layers. Curing may be effected by baking in a cavity mould at 180 DEG F. or less (preferably 130-150 DEG F.) and 5 p.s.i.g., and subsequently postcuring at 200-300 DEG F. Examples of mixes used for laminating glass cloth are: (a) styrene 105 parts, acrylonitrile 45 parts, benzoyl peroxide 1-5 parts, N-phenyl morpholine 2.25 parts, (b) dichlorostyrene 76.5 parts, acrylonitrile 23.5 parts, methylethyl ketone peroxide 2 parts, cobalt naphthenate (solution) 0.6 parts, (c) acrylonitrile 34 parts, styrene 59 parts, divinyl benzene (57%) 7 parts, benzoyl peroxide 2 parts, (d) acrylonitrile 50 parts, divinyl benzene (55%) 50 parts, benzoyl peroxide 1 part, (e) acrylonitrile 50 parts, n-butyl methacrylate 45 parts, ethylene dimethyacrylate 5 parts, benzoyl peroxide 1 part.