Method for matched die molding a fiber reinforced polyurethane foam molded product

US4298556A · kind A · utility

Assignee

• Firma Carl Freudenberg · DE

Inventors

• Peter Rutsch · Weinheim, DE
• Michael James Brehm · Allen, US

Key dates

• Filing date: Dec 13, 1979
• Grant date: Nov 3, 1981
• Expiry date: Dec 13, 1999

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C08J2375/04
• WIPO field: Other special machines
• WIPO sector: Mechanical engineering

Abstract

A fiber reinforcement is positioned on the female part of a matched die, and a reactive foaming mixture of polyol and isocyanate is placed on the reinforcement, the male part of the die set being then closed on the female part so as to compress the reinforcement and holding the die parts together while the mixture's foaming reaction occurs. So that the reinforcement can comprise finer than usual individual fiber thicknesses and be compressed more than usual by closing of the die while still filling all the voids between the fibers of the reinforcement with the foam produced by the mixture's reaction, from 5 to 30% by weight of a neutral ester having a boiling temperature higher than the foaming reaction temperature of the mixture, is initially added to the mixture before it is placed on the reinforcement and prior to closing of the die. This results in the foaming penetrating the voids between the fibers throughout the reinforcement between the mold parts more completely than is possible without using the ester.