Patent ID: 8574818
Filing Date: 2013-11-05
Classification: C08G,C08L,C09D,G03F

Abstract:
1. A method for preparing a photocrosslinkable composition, comprising the following steps: (a) hydrolysis and condensation of an [(epoxycycloalkyl)alkyl]trialkoxysilane in solution in an organoaqueous medium containing water, in a water/monomer initial molar ratio of between 3 and 15, and at least one water-miscible solvent, at a pH of between 1.6 and 4.0, by heating the solution at a temperature of between 50 and 70° C. for a period of between 180 and 350 minutes, so as to obtain a solution of an organomineral hybrid prepolymer, in which all or virtually all of the alkoxysilane groups have been hydrolyzed, and which comprises on average from 4 to 10 (epoxycycloalkyl)alkyl groups, per molecule, (b) cooling the resulting polyepoxide prepolymer composition to a temperature of between 15 and 25° C., (c) adding to this composition at least one cationic polymerization photoinitiator and at least one photosensitizer having a maximum absorption at a wavelength of between 300 and 420 nm, and adding a surfactant, (d) stirring the resulting composition for a period of between 10 and 120 minutes, at a temperature of between 15 and 25° C., (e) filtering the resulting composition through a filter comprising pores with an average size of between 1 μm and 5 μm, and (f) storing the resulting liquid filtrate at a temperature below 0° C. as the photocrosslinkable composition.