| 摘要 |
1526305 Thermosetting phenolic resin compositions UNION CARBIDE CORP 5 Sept 1975 [6 Sept 1974] 36653/75 Heading C3R [Also in Division B5] A thermosetting phenolic resin composition for use in a warm runner injection moulding process comprises (a) a moulding grade thermosetting phenolic resin, which is either (i) a resole or (ii) a novolak plus a crosslinking agent, e.g. hexamethylenetetramine, and (b) from 5-35 p.b.w. per 100 p.b.w. of (a), of a reactive para-substituted phenolic compound which has a melting point of from 35‹ to 160‹ C. and wherein the para-substituent is an alkyl, cycloalkyl, cycloalkenyl, phenyl, phenylalkyl or hydroxyphenyl alkyl group, the said reactive compound (b) being capable of reducing the viscosity of a moulding composition containing the moulding grade phenolic resin to a processable viscosity at a temperature at which the period of time within which the moulding composition cures to a thermoset state is longer than the period of time that the moulding composition is in the runner during a normal injection moulding operation. Preferred compounds (b) are p-t-butylphenol and p-cumylphenol. Moulding compositions containing the above thermosetting resin phenolic composition generally comprise one or more fillers, extenders, toughening agents, pigments, lubricants and reinforcing agents, and the moulding grade phenolic resin generally constitutes 30-55% wt. of the moulding composition. |
