Hoechst Aktiengesellschaft

Agfa-gevaert Ag

Agfa Gevaert Nv

Rudolf Neubauer

Stephan J Platzer

Andreas Elsaesser

Walter Mackert

Gerhard Buhr

Rudolf Zertani

Peter Lehmann

Guenter Hultzsch

Raimund Haas

Klaus Joerg

Gerhard Sprintschnik

Hans W Frass

Roman Keiper

Siegfried Nuernberger

Sabine Pilger

Ernst-August Hackmann

Dietmar Koenneke

A positive-working, radiation-sensitive recording material capable of being used for the production of planographic printing plates, comprising: an aluminum support and a radiation-sensitive layer coated thereon, wherein

Radiation-sensitive recording material for the production of

The mechanical roughening of the surface of a printing plate substrate comprising aluminum or an aluminum alloy is carried out by wet brushing with the use of a cylinder brush 1 in which brush rows 2, 3 having bundles of organic fibers 22 and metal wires 33 are arranged side by side on the surface 7. The suspension used for the wet brushing contains from 5 to 80% by weight of abrasive particles in water.

Process for the mechanical roughening of the surface of a printing plate

A radiation-sensitive recording material, in particular for producing planographic printing plates, is disclosed. The material is composed of a layer support and a positive-working, radiation-sensitive layer having a rough surface containing at least one 1,2-quinonediazide as a radiation-sensitive compound, a polycondensate or polymer as a binder insoluble in water and soluble or swellable in aqueous-alkaline solutions, a dye and a filler. At a layer weight of 3 g/m.sup.2 or less, the radiation-sensitive layer comprises a silicic acid product having a mean grain size in the range from 3 to 5 .mu.m with an exclusion limit of 15 .mu.m as a filler in such a quantity that it exhibits a Bekk smoothness in the range from 20 to 100 seconds (determined according to DIN 53 107, Method A). The layer additionally comprises a surfactant having polysiloxane units. The recording material shows good copying properties and technical printing properties, such as an advantageous evacuation time, screen evenness, low susceptibility to air occlusions, good resolving power and a good coating structure. The invention also relates to a process for producing a planographic printing plated, using the recording material according to the invention.

Radiation-sensitive recording material with a positive-working,

The present invention relates to a process for producing a negative-working photosensitive lithographic printing form, in which a negative-working photosensitive mixture which is dissolved in a solvent mixture and which contains a negative-working photosensitive compound and a polymeric binder which is insoluble in water but soluble in aqueous alkaline solution is applied to a base and the layer obtained is subsequently dried, which process comprises using a mixture of more than 2% by weight of at least one monoether of diethylene glycol with one or more organic solvent(s) having a boiling point below 200.degree. C. as the solvent mixture.

Process for producing a negative-working lithographic printing form

This invention relates to a developer mixture for washing out light-sensitive copying layers previously exposed in imagewise manner and containing a polymer of an N-vinyl amine, of vinyl alcohol or of a vinyl alcohol derivative, an alcohol being water-soluble in an amount less than 10% by weight, and water as the main constituent, the mixture containing as said polymer a copolymer which is water-soluble or which can be dispersed in water to form a stable dispersion, composed of (a) hydrophilic units of the formula I: ##STR1## wherein A is O-R or ##STR2## R is a hydrogen atom or a methyl group; R.sub.1 is a hydrogen atom, an alkyl group or an alkoxy alkyl group having 1 to 10 carbon atoms each or an aryl group with 6 to 10 carbon atoms; R.sub.2 is an alkyl group or an acyl group having 1 to 5 carbon atoms each, and wherein a homopolymer of the hydrophilic units is water-soluble and of (b) hydrophobic units of vinyl monomers whose homopolymer is water-insoluble and which have an aromatic or a long-chain aliphatic group as the substituent, the proportion of the hydrophobic units being sufficient to ensure that an 0.1% aqueous solution of said copolymer has a surface tension of not more than 50 mN/m and that the quantity of said copolymer is at least sufficient to emulsify any quantity of alcohol exceeding the solubility limit. The invention also relates to a process for developing exposed light-sensitive copying layers using said developer mixture.

Developer mixture for developing exposed light-sensistive copying layers

A light-sensitive composition for the preparation of printing plates and photoresists is described, which comprises as the light-sensitive compound a diazonium salt polycondensation product and as the binding agent a branched polyurethane resin which contains no terminal isocyanate groups and the terminal units of which are at least partially derived from dihydroxy compounds. The printing plates produced with this light-sensitive composition are easily developable with aqueous developer solutions and yield long press runs.

Light-sensitive diazo composition and material with branched

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Oestrich-Winkel, Germany

Rudolf Neubauer