Patent ID: 8318825

Claim:
A method of producing a polishing pad material comprising: reacting a polyether polyol compound with toluene diisocyanate (TDI) to prepare a first prepolymer, separately reacting the polyether polyol compound with 4,4′-dicyclohexylmethane diisocyanate (HMDI) to prepare second prepolymer, mixing the first and second prepolymers in the presence of the first and second isocyanate compounds to prepare a starting pre-polymer, wherein the amount of TDI and HMDI remaining in the starting prepolymer together is 20 wt % or less and the ratio of remaining HMDI to remaining TDI is 0.5 to 3.2:1, adding hydroxyl-free silicon-based surfactant to the starting prepolymer in an amount of 0.05 to 5 wt % based on the amount of starting prepolymer, stirring the component containing the surfactant to prepare a cell dispersion having inert gas bubbles dispersed therein, mixing a curing agent with the cell dispersion, casting a mixture into an open mold, and heating the mixture in an oven so as to cure the mixture in the mold and produce a polyurethane resin foam wherein the polyether polyol compound comprises both polytetramethylene glycol (PTMG) and diethlene glycol (DEG).