Process for producing a porous matrix

Claim 1

Process for producing a porous matrix having numerous interconnecting passageways therethrough and extending to the surfaces thereof which comprises entirely coating the surfaces of solid, substantially spherical particles of substantially uniform size in the range of about 30 to 90 microns with a solid, uncured thermosetting resin to a substantially uniform coating thickness provided by employing about 10 to 15 parts by weight of solid resin for each 100 parts of spherical particles and distributing said resin evenly over the surfaces of said particles, placing a mass of said coated particles in a heated mold, in the presence of an inert lubricant, subjecting said mass to pressure just sufficient to adhere the coated particles to each other at points of contact but not so much pressure as to fill the interstices between said coated particles, and then, curing the said resin to a unitary matrix in which the said resin is confluent at said point of contact while remaining in place as a uniform coating of essentially its original thickness over the surfaces of said particles in the interstices therebetween.