Method of making composite polishing layer for chemical mechanical polishing pad

A method of forming a chemical mechanical polishing pad composite polishing layer, comprising:

• providing a first polishing layer component of the chemical mechanical polishing pad composite polishing layer;
• wherein the first polishing layer component has a polishing side, a base surface, a plurality of periodic recesses and an average first component thickness, T1-avg, measured normal to the polishing side from the base surface to the polishing side;
• wherein the first polishing layer component comprises a first continuous non-fugitive polymeric phase;
• wherein the plurality of periodic recesses have an average recess depth, Davg, measured normal to the polishing side from the polishing side toward the base surface, wherein the average recess depth, Davg, is less than the average first component thickness, T1-avg;
• wherein the first continuous non-fugitive polymeric phase is a reaction product of a first continuous phase isocyanate-terminated urethane prepolymer having 8 to 12 wt % unreacted NCO groups and a first continuous phase curative;
• providing a poly side (P) liquid component, comprising at least one of a (P) side polyol, a (P) side polyamine and a (P) side alcohol amine;
• providing an iso side (I) liquid component, comprising at least one polyfunctional isocyanate;
• providing a pressurized gas;
• providing an axial mixing device having an internal cylindrical chamber;
• wherein the internal cylindrical chamber has a closed end, an open end, an axis of symmetry, at least one (P) side liquid feed port that opens into the internal cylindrical chamber, at least one (I) side liquid feed port that opens into the internal cylindrical chamber, and at least one tangential pressurized gas feed port that opens into the internal cylindrical chamber;
• wherein the closed end and the open end are perpendicular to the axis of symmetry;
• wherein the at least one (P) side liquid feed port and the at least one (I) side liquid feed port are arranged along a circumference of the internal cylindrical chamber proximate the closed end;
• wherein the at least one tangential pressurized gas feed port is arranged along the circumference of the internal cylindrical chamber downstream of the at least one (P) side liquid feed port and the at least one (I) side liquid feed port from the closed end;
• wherein the poly side (P) liquid component is introduced into the internal cylindrical chamber through the at least one (P) side liquid feed port at a (P) side charge pressure of 6,895 to 27,600 kPa;
• wherein the iso side (I) liquid component is introduced into the internal cylindrical chamber through the at least one (I) side liquid feed port at an (I) side charge pressure of 6,895 to 27,600 kPa;
• wherein a combined mass flow rate of the poly side (P) liquid component and the iso side (I) liquid component to the internal cylindrical chamber is 1 to 500 g/s;
• wherein the poly side (P) liquid component, the iso side (I) liquid component and the pressurized gas are intermixed within the internal cylindrical chamber to form a combination;
• wherein the pressurized gas is introduced into the internal cylindrical chamber through the at least one tangential pressurized gas feed port with a supply pressure of 150 to 1,500 kPa;
• wherein an inlet velocity into the internal cylindrical chamber of the pressurized gas is 50 to 600 m/s calculated based on ideal gas conditions at 20° C. and 1 atm pressure;
• discharging the combination from the open end of the internal cylindrical chamber toward the polishing side of the first polishing layer component at a velocity of 5 to 1,000 m/sec, filling the plurality of periodic recesses with the combination;
• allowing the combination to solidify as a second polishing layer component in the plurality of periodic recesses to form a composite structure;
• wherein the second polishing layer component is a second non-fugitive polymeric phase;
• and,
• deriving the chemical mechanical polishing pad composite polishing layer from the composite structure, wherein the chemical mechanical polishing pad composite polishing layer has a polishing surface on the polishing side of the first polishing layer component;
• and wherein the polishing surface is adapted for polishing a substrate.