Soluble fluorescent materials and optical brighteners in solvent precipitation film compositions

Abstract

Abstract THE DISCLOSED INVENTION RELATES TO OPAQUE FILMS WITH ENHANCED OPTICAL PROPERTIES PRODUCED BY THE THE INCLUSION OF SOLUBLE FLUORESCENT MATERIALS AND OTPICAL BRIGHTENERS IN THE OPAQUE FILMS IN SUCH A MANNER AS TO MAXIMIZE THEIR EFFECTIVENESS THEREIN. THE FILMS OF THID INVENTION, ABSENT THE ABOVE DESCRIBED ADDITIVES, ARE NON-POROUS, MICROCELLULAR AND OPAQUE IN AN OF THEMSELVES. THEREFORE, LESSER AMOUNTS OF THE ADDITIVES ARE NECESSARY TO OBTAIN DESIRED OPTICAL PROPERTIES. THE PREPARATION OF THE FILMS OF THE DISCLOSED INVENTION INVOLVES THE MIXING OF A FILMS FORMING POLYMER WITH A SOLVENT MIXTURE FOR THE FILM FORMING POLYMER, WHEREBY THE SOLVENT MIXTURE COMPRISES AT LEAST TWO MISCIBLE LIQUIDS, AT LEAST ONE OF THE LIQUIDS BEING A NONSOLVENT FOR THE POLYMER AND HAVING A LOWER VOLATILITY THAN THAT OF THE OTHER LIQUIDS IN THE MIXTURE AND A FLOURESCENT MATERIAL OR AN OPTICAL BRIGHTENER WHICH IS SOLUBLE IN SAID COMPOSITION. THE POLYMER SOLVENT MIXTURE IS THEN APPLIED TO A SUBSTRATE AND THE SOLVENT MIXTURE IS REMOVED AS BY EVAPORATION. DURING THE REMOVAL, A GELL FILM HAVING ENTRAPPED THEREIN THE LOW VOLATILTIY NON-SOLVENT IS FIRST FORMED AND UPON FURTHER EVAPORTATION, THE NON-SOLVENT IS REMOVED, LEAVING BEHIND SMALL CLOSED VOIDS IN ITS PLACE. THESE VIODS CAUSE THE FILM TO BE OPAQUE. THE ADDED INGREDIENTS ARE INCLUDED BY DISSOLVING THE IN THE SOLVENT MIXTURE OF THE ABOVE-DESCRIBED PROCESS PRIOR TO THE REMOVAL OF THE SOLVENT MIXTURE FROM THE COMPOSITION. D R A W I N G

Inventors

• 👤 Jerome A Seiner

Bibliographic Details