Toray Industries, Inc.

Shigeo Abiko

Tadami Kamaishi

Masaya Asano

Ken Kawamura

Takao Kitagawa

Mikio Tsuda

Masanao Isono

Yoichi Mori

Tetuo Suzuki

Chikara Ichijo

The present invention is concerned with a printing plate of which image formation is done by photoirradiation, having a front side covered waith a peelable or removable protective layer which contains a photofading material. The printing plate is safe against fogging to light and can be used under ordinary illumination.

Printing plate

A printing plate formed of a substrate and laminated thereon in the following order a primer layer and a photosensitive layer containing a quinonediazide compound and a silicone rubber layer, wherein the primer layer contains 0.1 to 25% by weight of a quinonediazide group. The printing plate of the present invention is excellent in dot reproduction, hardly causes cracking in the photosensitive layer, and has a wide latitutde in production.

Provided is a dry planographic printing plate containing on a base substrate a mixture which mixture comprises an organopolysiloxane; an alkoxy silane as a cross-linking agent represented by the formula R.sub.4-a-b R'.sub.a Si(OR').sub.b wherein a is 0 or 1, b is 2 or 3 and a+b is at most 3, R is an organic group containing a polar group or double bond and OR' is an alkoxy group; and a compound as a cross-linking catalyst represented by the formula (R.sup.1 O)(R.sup.2 O)(R.sup.3 O)(R.sup.4 O)M wherein M is titanium or zirconium, R.sup.1, R.sup.2, R.sup.3 and R.sup.4 are each an organic group.

Dry planographic printing plate

A waterless planographic printing plate having toner image areas of ink receptivity and non-image areas of ink releasability is provided, which plate has a substrate and an overlying layer coated on the substrate. The overlying layer is predominantly comprised of a reaction product of 50 to 99% by weight of a polymeric material having, on the average, at least two hydroxyl groups per molecule and exhibiting a high adhesion to the ink-receptive toner, and 1 to 50% by weight of an organopolysiloxane having hydroxyl end groups. The overlying layer preferably consists of a relatively thin surface layer substantially composed of the organopolysiloxane, and a relatively thick inner layer sandwiched between the surface layer and the substrate and having an islands-in-sea heterophase structure composed of the organopolysiloxane islands substantially uniformly dispersed in the sea of the polymeric material. The relatively thin surface layer has holes through which the inner layer predominantly composed of the polymeric material is exposed.

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Shiga, Japan

Shigeo Abiko