Dry photosensitive plate for lithographic printing - comprises polyether (meth)acrylate light sensitive coat, photopolymerisation initiator and film forming polymer covered by silicon rubber

摘要

Dry PS plate has a substrate with a light-sensitive resin coating covered by a silicone rubber coating. The resin coating of mono- or di-(meth)acrylated polyethylene oxide or polypropylene oxide of formula: CH2=C(R1)-CO-O-(CH2-CH(R2)-O)n-R3 (I) (where R1 and R2 independently = H or Me; R3 = H, Me, Et, (substd.) phenyl, -COOC'R1(=CH2 or p-C6H4-C(CH3)2-p-C6H4-O-(CH2-CH(R2)-O)m-CO-C(R1=CH2); n and (n+m) = 6-46, except that R3 not = an ethylenically unsatd. gp. if n = 6-23); a photopolymerisation initiator (II) and a film-forming polymer (III). Pref. n or (n+m) = 8-40. The resin coat contains 1-80 (wt.)% (I), 0.1-20% (II) and 10-95% (III) (w.r.t. solids). It may also contain another ethylenically unsatd. monomer or oligomer. (II) is a vic-polyketaldonyl cpd.; alpha-carbonyl cpd.; acyloin ether; aromatic acyloin cpd. with an alpha-hydrocarbyl substit.; polycyclic quinone cpd.; combination of triarylimidazole dimer and p-aminophenyl ketone; benzothiazole cpds., opt. with trihalomethyl-s-triazine cpds., etc.; (III) is a (meth)acrylic or crotonic acid polymer; (partly esterified) maleic acid copolymer; acid cellulose deriv.; polyvinylpyrrolidone; polyethylene butyral, formal or chloride; PVA or its partial acetal, etc. USE/ADVANTAGE - The plate is used in lithographic printing. The deg. of cure of the silicone rubber layer and its adhesion to the light-sensitive coat are controlled to ensure excellent imaging properties and printing durability.