| 摘要 |
997,170. Photosensitive compositions. HORIZONS Inc. March 12,1962 [March 13,1961], No. 9472/62. Heading G2C. A photosensitive composition comprises a light-sensitive organic halogen compound of the formula R-C-X 3 where R is H, C1, Br, alkyl, aryl substituted alkyl or substituted aryl and X is Cl, Br or I, and a dye base having one of the following formulae:- wherein B is H or alkyl, R is an alkyl, aralkyl or aryl group, R<SP>1</SP> is H, CN or the radical R 1 and R 2 are alkyl or benzyl groups, d, e and g are 1 or 2,n is an integer from 1 to 4, L and L<SP>1</SP> are -CH= or -N= but at least one in each formula is -N=, or L is formula III may be -(CN)=, and Q, Z and Z<SP>1</SP> complete heterocyclic nuclei having 5 or 6 atoms in the ring. Exposure to light gives a coloured print-out image which may be enhanced by heating, which makes the image and non-image areas differentially soluble in selected solvents, so that either the unexposed or exposed areas may be washed away. In the latter case, the remaining unexposed areas may be re-exposed to give a positive image. Since the exposed areas are hydrophilic and the non-exposed areas are hydrophobic, the invention may be used for the production of lithographic printing plates. In the examples, the organic halogen compound is carbon tetrabromide or pentabromoethane and it may be coated in a binder of ethyl cellulose or eicosane. The colour images produced according to the invention may be converted into lakes by treatment with salts of copper, chromium, cobalt, phosphotungstic acid, phosphomolybdic acid of aluminium. Specification 959,037 is referred to. |
