Claims
- 1. A process for the preparation of a relief printing plate which comprises exposing one face of a photopolymerizable element in the form of a sheet imagewise to actinic radiation, said element comprising
- a. an addition polymerizable ethylenically unsaturated compound having a boiling point above 100.degree.C at normal atmospheric pressure;
- b. a free radical generating addition polymerization initiator activatable by actinic radiation;
- c. a compatible polyurethane binding agent comprising the product of reaction of
- i. 4,4'-methylenebis(phenyl isocyanate);
- ii. a polycaprolactone diol having a molecular weight in the range of about 1,000 to about 2,500; and
- iii. a mixture of at least two different aliphatic diols of from 2 to 6 carbon atoms, inclusive;
- the ratio of equivalents of polycaprolactone diol (ii) to total equivalents of said aliphatic diols (iii) being within the range of 1:1.5 to 1:7, and the ratio of equivalents of isocyanate (i) to total equivalents of polyols (ii) and (iii) being within the range of about 0.94:1 to 0.98:1,
- and developing the relief image on the exposed face of said element by subjecting the latter to etching with a solvent in which the unexposed portions of said photopolymerizable element are soluble.
- 2. A process according to claim 1 wherein, in the case where the starting photopolymerizable element is unsupported, the face of the latter which has not been exposed imagewise is exposed totally to actinic radiation to produce an integral polymerized supporting layer, prior to development of the relief image on the face which has been exposed imagewise to actinic radiation.
Parent Case Info
This application is a division of application Ser. No. 383,377, filed July 27, 1973, now U.S. Pat. No. 3,912,516.
US Referenced Citations (8)
Non-Patent Literature Citations (1)
Entry |
Saunder et al., Polyurethanes, Chemistry and Technology, Part I, 1963, pp. 228-232. |
Divisions (1)
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Number |
Date |
Country |
Parent |
383377 |
Jul 1973 |
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