Patent ID: 6156146
Filing Date: 2000-12-05
Classification: B29C,B29L,B32B,Y10T

Abstract:
A process for making a layered product having a honeycomb core having cells filled with a foam material, said process comprising the steps of:(a) placing a first layer of an uncured heat-expandable foamable material on the top side of a central honeycomb core having empty cells, and placing a second layer of an uncured heat-expandable foamable material on the bottom side of said central honeycomb core;(b) placing a first layer of an uncured preform material distal to said central honeycomb core and above said first layer of uncured heat-expandable foamable material, and placing a second layer of an uncured preform material distal to said central honeycomb core and below said second layer of uncured heat-expandable foamable material;(c) placing the charge made by steps (a) and (b) inside a mold and closing the mold;(d) heating said mold to the cure temperature of said heat-expandable foamable material, and holding said mold at this temperature for sufficient time to expand and cure said heat-expandable foamable material;(e) reducing the temperature of said mold to the injection temperature of a selected resin transfer molding (RTM) resin system, and injecting said selected resin transfer molding (RTM) resin system into said mold;(f) holding the temperature of said mold at the cure temperature for said resin transfer molding (RTM) resin system for sufficient time to cure said resin system; and,(g) removing the product from said mold after curing is completed.