Basf Aktiengesellschaft

Dietrich Saenger

Reinhold J Leyrer

Heiner Goerrissen

Helmut Barzynski

Manfred Walter

John Lynch

Hartmut Zeiner

Sabine Kielhorn-Bayer

Wilhelm Schuette

Uwe Klinsmann

UV-stabilized polyoxymethylene molding materials

Molding materials of polyoxymethylene homopolymers and/or copolymers and

Gravure printing plates comprising a plastic printing layer applied on a printing plate base are produced by a method wherein a solid photosensitive layer (L) firmly bonded on the printing plate base is exposed imagewise to actinic light, and the exposed layer is washed out with a developer and then subjected to thermal hardening to form the plastic printing layer. In this process, the photosensitive layer (L) employed contains, as the photosensitive component, a compound possessing two or more aromatic and/or heteroaromatic o-nitrocarbinol ester groups, and a compound which effects crosslinking and possesses two or more reactive groups which are capable of reacting with --COOH groups under the action of heat to form a covalent chemical bond. After imagewise exposure, the layer is either washed out with an aqueous developer, post-exposed uniformly to actinic light and then subjected to thermal hardening and crosslinking, or subjected to selective thermal hardening and crosslinking in the exposed areas and then washed out with a developer.

Production of gravure printing plates having plastic printing layers

Relief images or resist images are produced by a negative-working process, using a photosensitive resist layer which is applied on a base and contains a compound possessing two or more aromatic and/or heteroaromatic o-nitrocarbinol ester groups as well as a crosslinking compound possessing two or more reactive groups which are capable, under the action of heat, of reacting with carboxyl groups to form a covalent chemical bond. To produce the relief images or resist images, the photosensitive resist layer is first exposed imagewise to actinic light, the exposed areas of this layer are subjected to selective thermal hardening and crosslinking and the resist layer is then post-exposed uniformly to actinic light and finally washed out with an aqueous developer.

Production of relief images or resist images by a negative-working method

Relief images or resist images are produced by a positive-working process, using a solid photosensitive resist layer which is applied to a base and contains a compound possessing two or more aromatic and/or heteroaromatic o-nitrocarbinol ester groups and crosslinking compounds possessing two or more reactive groups which are capable, under the action of heat, of reacting with carboxyl groups to form a covalent chemical bond. To produce the relief images or resist images, the photosensitive resist layer is first exposed imagewise to actinic light, the exposed areas of this layer are then washed out with an aqueous developer, the remaining resist layer is post-exposed uniformly to actinic light and finally the post-exposed resist layer is thermally crosslinked and hardened.

Production of relief images or resist images by a positive-working method

Photopolymerizable coating and recording materials, such as photopolymer dry film resist materials and photoresist materials, comprising at least one photopolymerizable olefinic compound, which materials contain, as activated photoinitiator system, a carbonyl compound that, when exposed to actinic light, forms free radicals which initiate polymerization, such as benzophenone and benzophenone derivatives, as well as a benzene compound having at least two dichloromethyl groups bound to the benzene nucleus, such as bis(dichloromethyl)-benzene and 2,5-dichloro-1,4-bis(dichloromethyl)benzene, and preferably also a dye which changes color in the presence of acid. The coating and recording materials of the invention exhibit improved curing when exposed to ultraviolet light for the usual periods and can be readily washed out with solvents without any damage to the exposed areas.

Photopolymerizable coating and recording materials containing a

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Frankenthal, Germany

Dietrich Saenger