Patent ID: 6174931
Filing Date: 2001-01-16
Classification: C09J

Abstract:
A multi-stage irradiation process for the production of an acrylic-based composition comprising the sequential steps of:(a) forming a solvent-free monomeric mixture or solvent-free partially prepolymerized syrup comprising:(i) about 50-100 parts by weight of at least one acrylic acid ester of an alkyl alcohol, said alcohol containing from 1 to 14 carbon atoms;(ii) about 0-50 parts by weight of at least one copolymerizable monomer; and(iii) a photoinitiator;(b) irradiating the resulting monomeric mixture or partially prepolymerized syrup with electromagnetic radiation of from about 280 to 500 nanometers wavelength and from 0.01 to 20 milliwatts per centimeter squared (mW/cm.sup.2) average light intensity to effect conversion of from about 5 up to and including 70 weight % of said monomeric mixture or partially prepolymerized syrup to an acrylic copolymer; and(c) thereafter, further irradiating the resulting acrylic copolymer resulting from step (b) with electromagnetic radiation of from about 280 to 500 nm wavelength and having an average light intensity of greater than 20 mW/cm.sup.2 to at least substantially complete the polymerization reaction of said acrylic copolymer.