Process for preparing photoconductive compositions and sheets coated therewith

Claim 1

PROCESS OF MAKING A PHOTOCONDUCTIVE SHEET SUITABLE FOR MAKING PRINTS UNDER A WIDE RANGE OF RELATIVE HUMIDITY CONDITIONS INCLUDING HUMIDITIES IN EXCESS OF 75%, COMPRISING THE STEPS OF PREPARING A WATER EMULSION CONSISTING OF A STYRENE AND AN ACRYLATE IN THE RATIO OF 20 TO 70 PARTS STYRENE BALANCE ALKYL ACRYLATE, A STYRENE-MALEIC ANHYDRIDE COPOLYMER, WATER, AND A VOLATILE ALKALINE MATERIAL IN AN AMOUNT SUFFICIENT TO RENDER SAID STYRENE-MALEIC ANHYDRIDE COPOLYMER SOLUBLE IN SAID EMULSION, HEATING TO EFFECT COPOLYMERIZATION OF SAID STYRENE, ACRYLATE, AND STYRENE-MALEIC ANHYDRIDE COPOLYMER PREPARING A WATER DISPERSION OF ZINC OXIDE, UNIFORMLY MIXING SAID EMULSION AND SAID DISPERSION WITH SUFFICIENT WATER TO ADAPT THE RESULTING COMPOSITION TO A COATING STEP, COATING SAID MIXTURE ONTO A BACKING SHEET, AND THEN HEATING THE RESULTING COATING TO DRIVE OFF WATER AND VOLATILE CONSTITUTENTS, AND REACT CARBOXYL GROUPS OF SAID MALEIC ANHYDRIDE WITH SAID ZINC OXIDE TO FORM A HYDROPHOBIC COMPLEX THEREWITH, THE FINAL DRIED PRODUCT CONSISTING OF ONE TO 10 PARTS ZINC OXIDE TO ONE PART OF THE POLYMERS.