MATERIAL PREIMPREGNAT SI PROCEDEU DE REALIZARE A ACESTUIA

摘要

1353816 Fibre reinforced polyester resins PRODUITS CHIMIQUES PECHINEYSAINT-GOBAIN and REGIE NATIONALE DES USINES RENAULT 8 July 1971 [9 July 1970] 32123/71 Heading C3P A curable, fibre reinforced, resin material comprising from 10 to 70% by weight of reinforcing fibres and from 30 to 90% by weight of an impregnating composition comprised of a mixture of 50 to 98% by weight of a copolymerizable polyester resin (i.e. a mixture of an ethylenically unsaturated polyester, a crosslinking ethylenically unsaturated monomer and a polymerization inhibitor) and 2 to 50% by weight of a solution of an oligoester having maleic acid end groups, the composition containing, based on the resin/oligoester solution mixture, 0À5% to 2% by weight of a polymerization initiator and from 1 to 10% by weight of an oxide or hydroxide of a metal selected from Group II of the periodic classification of elements may be prepared by impregnating the reinforcing fibres with the impregnating composition, and heating the impregnated fibres to a temperature ranging from 50‹ to 100‹ C. for a time ranging from 20 seconds to 15 minutes to increase the viscosity of the impregnating composition. The oligoester solution is composed of a mixture of the oligoester and a cross-linking ethylenically unsaturated monomer containing a polymerization inhibitor. The oligoesters having maleic acid end groups are compounds formed by reaction of maleic anhydride with one or more polyhydroxylated compounds, in the proportions of one mole of maleic anhydride to each hydroxyl group. The polyhydroxylated compounds used contain at least two hydroxylated groups selected from the saturated or unsaturated aliphatic, cycloaliphatic or aromatic alcohols which alcohols can contain as substituent an alkyl group, alkoxy group or halogen atoms and may also contain in their molecule one or more ester and/or ether and/or amide and/or urethane groups. In the examples a glass fibre strip, a strip of glass fibre mat and cut glass fibres are impregnated with a composition comprising polyesters prepared from phthalic anhydride, maleic anhydride, 1,2-propylene-glycol and isophthalic acid, styrene, hydroquinone, an oligoester of maleic anhydride and 2,2,4- trimethylpentane 1,3-diol, an oligoester of maleic anhydride and neopentyl glycol, dicumyl peroxide, calcined magnesia, calcium carbonate, magnesium stearate, clay, alkyl phthalate, tertiary butyl perbenzoate, calcium stearate and dolomite. The impregnated fibres are heated in a high frequency electric field, between two heating plates or in a ventilated oven and then moulded.