Patent ID: 7537446

Claim:
An apparatus for forming a chemical mechanical polishing pad, comprising: a tank with polymeric materials; a storage silo with microspheres; an isocyanate storage tank with isocyanates; a premix prep tank for forming a pre-mixture of the polymeric materials and the microspheres, wherein the premix prep tank comprises a recirculation loop for recirculating the pre-mixture and controlling the bulk density of the pre-mixture, wherein the recirculation loop comprises an in line densitometer for monitoring the bulk density of the pre-mixture passing therethrough and controlling the bulk density; a premix run tank for storing the pre-mixture; a mixer for forming a mixture of the pre-mixture and the isocyanates; a closed mold for reaction-injection molding the mixture; and a vacuum for degassing at least one of the tank, isocyanate storage tank or the mold.