| abstract |
A gel for thermotropic layers is obtained by energy-rich light irradiation of a mixture containing (A) a non-crosslinked polymer; (B) radically polymerisable monomers; (C) water and/or organic solvent; and (D) a photo-initiator of formula (I), where R<1>, R<2> = 1-10C alkyl; and R<3>-R<7> = H, 1-10C alkyl or 5-10C aryl, with the proviso that at least one of R<3>- R<7> is a hydrophilic group which is a carboxylic acid, carboxylate, sulphonic acid, sulphonate, OH or polyalkylene oxide group or an up to 30C organic group containing such a hydrophilic group. Preferably the composition comprises 0.1-40 wt.% (A), 1-30 wt.% (B) and 30-98.9 wt.% (C) (especially water). The photo-initiator is "Darocure" 2959 (RTM). |