Chemical mechanical polishing pad and method of making same

A method of making a chemical mechanical polishing layer, comprising:

• providing a poly side (P) liquid component, comprising from 1 to 5 wt. % of an amine-carbon dioxide adduct;
• and from 25 to 95 wt % of a (P) side polyol which is a high molecular weight polyether polyol having a number average molecular weight, MN, of 2,500 to 100,000 and an average of 4 to 8 hydroxyl groups per molecule;
• providing a iso side (I) liquid component, comprising at least one at least one (I) side 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 6 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 90 to 600 m/s;
• discharging the combination from the open end of the internal cylindrical chamber toward a target at a velocity of 10 to 300 m/sec;
• allowing the combination to solidify into a cake;
• and,
• deriving the chemical mechanical polishing layer from the cake, wherein the chemical mechanical polishing layer has a porosity of ≧10 vol % and a polishing surface adapted for polishing a substrate.