Abstract A novel process is disclosed for converting a polystyrene or polystyreneacrylonitrile latex emulsion into a novel product comprising a white, opaque pigment for use as a paper filler, a paper coating pigment, a paint pigment, or for any other application where optimum optical effects are desired. The process comprises the high shear mixing of a polystyrenecontaining aqueous emulsion with a swelling agent which penetrates the polymer or copolymer particle thereby causing it to swell, and then a final step for setting the particle in its swollen state. When using a partially water miscible swelling agent, the emulsion may be washed and filtered to remove the swelling agent from the particle thereby setting it in the swollen state, but for an essentially non-water miscible swelling agent, the emulsion need only be filtered and dried to set the swollen particles, and, where removal of the swelling agent is not necessary, the treated emulsion may be used without the filtering or drying steps.
PAPER COMPRISING CELLULOSIC FIBERS AND A SYNTHETIC, BLUSHED POLYSTYRENE PIGMENT FILLER PREPARED FROM A POLYSTYRENE EMULSION, SAID BLUSHED POLYSTYRENE PIGMENT FILLER CONSISTING ESSENTIALLY OF SPHERICAL PARTICLES HAVING AN AIR-CONTAINING MICROPOROUS STRUCTURE AS A RESULT OF AIR-SOLID INTERFACES WITHIN THE FILLER PARTICLES AND HAVING A PARTICLE SIZE OF FROM ABOUT 0. 1 TO 0.2 MICRON AND A SCATTERING COEFFICIENT OF ABOUT 0.64, SAID BLUSHED POLYSTYRENE PIGMENT BEING CAPABLE OF INCREASING THE B&L OPACITY OF A SHEET OF PAPER HAVING AN OPACITY OF ABOUT 71 WITHOUT SAID PIGMENT BY ABOUT 8 POINTS WHEN SAID PAPER IS PROVIDED WITH ABOUT 4.66% BY WEIGHT OF SAID BLUSHED PIGMENT.
Claim 2
Dependent Claim
104 words
PAPER COMPRISING CELLULOSIC FIBERS AND A SYNTHETIC, BLUSHED POLYSTYRENE PIGMENT FILLER PREPARED FROM A POLYSTYRENE EMULSION, SAID BLUSHED POLYSTYRENE PIGMENT FILLER CONSISTING ESSENTIALLY OF SPHERICAL PARTICLES HAVING AN AIR-CONTAINING MICROPOROUS STRUCTURE AS A RESULT OF AIR-SOLID INTERFACES WITHIN THE FILLER PARTICLES AND HAVING A PARTICLE SIZE OF FROM ABOUT 0. 1 TO 0.2 MICRON AND A SCATTERING COEFFICIENT OF ABOUT 0.64, SAID BLUSHED POLYSTYRENE PIGMENT BEING CAPABLE OF INCREASING THE B&L OPACITY OF A SHEET OF PAPER HAVING AN OPACITY OF ABOUT 71 WITHOUT SAID PIGMENT BY ABOUT 8 POINTS WHEN SAID PAPER IS PROVIDED WITH ABOUT 4.66% BY WEIGHT OF SAID BLUSHED PIGMENT.