Diffusion control layer for photographic diffusion transfer materials - comprises graft copolymer with grafted units of hydrophobic monomer and monomer capable of beta elimination in alkaline environment

摘要

Photographic diffusion transfer prod. comprises a support with >=1 of (a) a photosensitive Ag halide emulsion layer with an associated processing compsn.-soluble, diffusible image-forming material; (b) a polymeric acid layer-and (c) an image-receiving layer, together with (d) a diffusion control layer comprising a graft copolymer (I). (II) has an organic polymeric backbone with grafted recurring units of (i) a hydrophobic monomer and (ii) units of a monomer capable of undergoing beta-elimination in an alkaline medium, of formula: R- CO- O- C(A)(E)- CH (D) (Y) (II). In (II), R is an ethylenically unsatd. 2-5 C alkyl gp., A, D and E are H, methyl or phenyl, provided that >1 of A, D and E is methyl or phenyl, and Y is an activating gp. (e.g. CN). The diffusion control layer controls premature migration of active materials in photographic multilayer diffusion transfer prods., e.g. to prevent premature migration of colour-providing materials during processing, which gives undesirable inter-image effects.