PHOTORESIST-FORMING COMPOSITIONS

1,223,632. Photocrosslinkable compositions. KONISHIBOKU PHOTO INDUSTRY CO. Ltd. 24 April, 1968 [25 April, 1967], No. 19469/68. Heading C3P. [Also in Division G2] A photoresist-forming (photocrosslinkable) composition comprises (a) a photoactivator containing a polyhalogenated methyl group which is capable of forming a free radical on exposure to light and (b) a polymer consisting of or containing units of the formula wherein A is H or a carboxylic acid or amide group, X is a divalent organic group, R 1 is H or C 1 -C 3 alkyl, R 2 is H, C 1 -C 3 alkyl or a substituted or unsubstituted phenyl group, and each of R 3 and R 4 , which may be the same or different, is H or C 1 -C 3 alkyl, with the proviso that in Formula II R 2 and R 3 , together with the N atom and benzene nucleus may form a heterocyclic ring system, or R 3 and R 4 together with the benzene nucleus may form a naphthalene ring system. Polymer (b) may be a homopolymer or a copolymer additionally containing units of one or more other monomers, e.g. styrene, acrylonitrile, vinyl acetate, acrylic, methacrylic or α- chloroacrylic acid or an alkyl ester thereof, itaconic acid, maleic anhydride or vinylidene chloride. In Formula I X may represent, for example, -COOCH 2 CH 2 -, -CONHCH 2 CH 2 - -COSCH 2 CH 2 -, -CONH-, -CH 2 -, -C 6 H 4 SO 2 NH-, -C 6 H 4 SO 2 O-C 6 H 4 - or -CONH-C 6 H 4 . Suitable as photoactivators (a) are compounds of the formula R1CX 2 R2, R4-SO-CX 2 R2, R4-SO 2 -CX 2 R2 or where R1 is H, alkyl, hydroxyalkyl, aryl, halogen or a heterocyclic ring, R2 is H or halogen, R3 is nitro, halogen or alkyl, R4 is alkyl, haloalkyl, aryl or a heterocyclic ring, and X is Cl or Br. The compositions can be colour sensitized by including therein an acridine dye, a merocyanine dye or a styryl dye. The preparations are described of (i) poly- (2 - N - ethyl - N - phenylaminoethyl methacrylate) and (ii) a copolymer of N-(2-N-ethyl- N-phenylaminoethyl)-methacrylamide and styrene by polymerizing the corresponding monomer(s) in methyl ethyl ketone using azobisisobutyronitrile as initiator.