Process for production of pigmented film-forming materials

Claim 1

PROCESS FOR THE PRODUCTION OF A PIGMENTED WATERINSOLUBLE FILM-FORMING SUBSTANCE SUBSTANTIALLY DEVOID OF WATER-SOLUBLE SALTS AND SUITABLE FOR SPINNING INTO ARTIFICIAL FILAMENTS, FROM A PIGMENTED PREPARATION CONTAINING WATERSOLUBLE SALTS, WHICH COMPRISES FORMING A DOUGH FROM THE SALT-CONTAINING PIGMENT, A WATER-INSOLUBLE FILM-FORMING MATERIAL HAVING A WATER IMBIBITION OF FROM ABOUT 10% TO ABOUT 40% AT 20* C. AND A VOLATILE SOFTENING AGENT FOR THE LATTER, MECHANICALLY WORKING THE DOUGH, WHILE EVAPORATING THE SOFTENING AGENT TO DISPERSE THE PIGMENT FINELY THROUGHOUT THE DOUGH AND TO BREAK UP THE PIGMENT PARTICLES, CONTINUING THE WORKING AND EVAPORATION OF THE SOFTENING AGENT UNTIL THE LATTER IS SUBSTANTIALLY ALL REMOVED AND A SOLID COMPACT INTIMATE MIXTURE OF SAID PIGMENT AND SAID FILAMENT-FORMING MATERIAL IS OBTAINED, AND SUBJECTING THE SOLID COMPACT MIXTURE, IN SUCH FORM THAT NO POINT THEREIN IS MORE THAN ABOUT 0.05 INCHES FROM A SURFACE THEREOF, TO AN AQUEOUS EXTRACTION UNTIL THE WATER SOLUBLE SALTS HAVE BEEN SUBSTANTIALLY REMOVED.