Method for making mat-molded rim parts

DETAILED DESCRIPTION The present invention is directed to a process for the preparation of a high strength composite comprising fibrous reinforcing material inpregnated with a reaction injection molded polyisocyanurate resin said process comprising: 1.
providing a mold containing said fibrous reinforcing material and said mold equipped with means for decreasing an overflow volume of polyisocyanurate resin forming ingredients received to a final volume of said ingredients; 2.
evacuating said mold; 3.
injecting into said evacuated mold said resin forming ingredients in an amount in excess of that required to fill said final volume thereby causing said overflow volume; 4.
pressurizing said mold prior to gelation of said resin forming ingredients thereby causing a decrease in at least a portion of said overflow volume; and 5.
maintaining said pressure at least until said gelation has occurred.
This invention is also directed to the high strength composites prepared by the above method.
The term "high strength" in reference to the present composites means a composite having a flexural modulus of at least 300,000 psi as determined in accordance with ASTM D-79 Test Method I Procedure A.
Surprisingly it has been found that a particular modification of the prior art epoxy MMRIM process will allow for the preparation of the high strength polyisocyanurate composites in accordance with the present invention.
The surprising feature is the fact that the pressure range disclosed for the epoxy resins is too low for present polyisocyanurate resins.
The latter require a minimum pressure which exceeds that required in the art.