Photopolymerizable compositions and elements and process of making reliefs therefrom

Claim 1

A PHOTOPOLYNERIZABLE COMPRISING (1) A NORMALLY NON-GASEOUS, ADDITION POLYNERIZABLE, ETHYLENICALLY UNSATURATED COMPOUND HAVING ANORMAL BOILING POINT GREATER THAN 100* C. AT ATMOSPHERIC PRESSURE, HAVING A MOLECULAR WEIGHT FROM ABOUT 100 TO ABOUT 1500, CONTAINING AT LEAST ONE ADDITION POLYMERIZABLE ETHYLENIC LINKAGE FOR EACH 300 UNITS OF MOLECULAR WEIGHT, AND BEING CAPABLE OF FORMING A HIGH POLYMER BY PHOTO-INITIATED ADDITION POLYMERIZATION IN THE PRESENCE OF AN ADDITION POLYMERIZATION INITIATOR THEREFOR ACTIVATED BY ACTINIC LIGHT; (2) A POLYVINYL ALCOHOL DERIVATIVE HAVING A MOLECULAR WEIGHT GREATER THAN 10,000 TAKEN FROM THE GROUP CONSISTING OF POLYVINYL ESTERS OF MONO-SUBSTITUTED ACIDS, POLYVINYL ETHERS OF MONOSUBSTITUTED ALCOHOLS, POLYVINYL ACETALS OF MONOSUBSTITUTED ALDEHYDES AND SUCH DERIVATIVES CONTAINING MORE THAN ONE TYPE OF THE ESTER, ETHER AND ACETAL GROUPS, SAID DERIVATIVE BEING FURTHER CHARACTERIZED IN THIS SAID MONO-SUBSTITUTED ACIDS, ETHERS AND ALDEHYDES CONTAIN NOT MORE THAN SEVEN CARBON ATOMS, AND THE SUBSTITUENT OF SAID MONO-SUBSTITUENT COMPOUNDS IS TAKEN FRON THE CLASS CONSISTING OF FREE OXYAACID GROUPS AND ALKALI METAL, AMMONIUM AND AMINE SALTS THEREOF, AND SAID DERIVATIVES ARE SOLUBLE TO THE EXTENT OF AT LEAST 10% BY WEIGHT IN 2% AQUEOUE AMMONIA SOLUTION, AND IN FREE ACID FROM HAVE A NEUTRALIZATION EQUIVALENT FROM ABOUT 115 TO ABOUT 2500 AND CONTAIN WITHIN THE WEIGHT PERCENT LIMITS REPRESENTED BY THE AREA X, Y,Z,W IN FIG 1 OF THE DRAQING COMBINED VINYL ALCOHOL UNITS CARRYING THE AFORESAID OXYACID GROUPS, COMBINED VINYL ALCOHOL UNITS WITH UNSUBSTITUTED HYDROXYLS, AND COMBINED VINYL ALCOHOL UNITS CARRYING LATERAL NEUTRAL GROUPS IN RESPECTIVE AMOUNTS TO SATISFY THE WEIGHT PERCENT LIMITS CALLED FOR IN THE SAME SAID AREA X,Y,Z,W; AND (3) POLYMERIZATION-EFFECTIVE AMOUNTS OF AN ADDITION POLYMERIZATION INITIATOR ACTIVATABLE BY ACTINIC LIGHT AND THERMALLY INACTIVE BELOW 85* C.