is then added dropwise to 5 liters of water the precipitate is collected by filtration and then dried in an oven the polymer melt temperature is 110 u00b0 145 u00b0 c in the following examples diazo sensitizers isocyanates and novolaks are selected from tables i iii respectively in addition novolaks are reacted with isocyanates to form isocyanate modified resins according to the formulas enumerated in table iv the general procedure for the preparation of resins 1 9 in table iv follows in a 3 necked flask equipped with a stirrer reflux condenser and drying tube tetrahydrofuran is introduced and then the appropriate novolak resin added in one or two portions the isocyanate and four drops of cobalt naphthenate are added with concurrent heating to 60 u00b0 c the reaction time is three hours at 60 u00b0 c next the solution is cooled to room temperature with continued stirring and stored until used table iv______________________________________ isocyanate modified novolak resinsthe resins are the products of the reaction ofthe ingredients shown all weights are in grams ______________________________________1 alnovol pn 430 144 18 butyl isocyanate 4 96 toluene diisocyanate trimethylolpropane adduct 1 862 alnovol pn 430 96 2 diphenylmethan 4 4 39 diisocyanate 2 53 alnovol pn 320 173 0 reaction product of toluene diisocyanate and hexamethylene diisocyanate 3 2 17 44 alnovol pn 430 140 0 toluene diisocyanate trimethylolpropane adduct 6 565 alnovol pn 430 233 0 trimethyl hexamethylene diisocyanate 5 256 alnovol pn 430 187 0 reaction product of toluene.