Radiation imagery chemistry: process – composition – or product th – Imaging affecting physical property of radiation sensitive... – Making printing plates
Patent
1982-03-10
1984-02-14
Bowers, Jr., Charles L.
Radiation imagery chemistry: process, composition, or product th
Imaging affecting physical property of radiation sensitive...
Making printing plates
430165, 430275, 430276, 430309, 430331, 101456, 101458, 101465, G03F 708
Patent
active
044317247
ABSTRACT:
An offset printing plate is provided comprising a carbon steel substrate with printing and non-printing areas on its surface. The printing areas are made of a light-sensitive top layer material based on derivatives of ortho-naphthoquinonediazide-sulphonic or carboxylic acids or a light-sensitive top layer material comprising a photopolymerizable composition. These printing areas form a relief over the plate surface. The non-printing areas are made of a hydrophilized metal of the substrate hydrophilized carbon steel.
A process for making an offset printing plate comprises application, onto a carbon steel substrate, of a light sensitive top layer based on derivatives of ortho-naphthoquinonediazide-sulphonic or carboxylic acids or a light-sensitive top layer comprising a photopolymerizable composition. The thus-applied top layer is dried. Onto the dried top layer an image is transferred from a photo-mask, a diapositive in the case of using a top layer based on derivatives of ortho-naphthoquinonediazide-sulphonic or carboxylic acids, and from a negative in the case of using a top layer comprising a photopolymerizable composition. The image is developed by removing regions of the top layer from the non-printing areas by means of a 0.2-1.5% aqueous solution of alkali metal salts or alkali metal hydroxides at a temperature ranging from 18.degree. to 25.degree. C. The non-printing areas are hydrophilized by means of an aqueous solution containing 5 to 10% of a salt formed by an alkali metal and a cyanide inorganic complex, and 0.5 to 2% of an organic hydrophilic colloid at a temperature ranging from 20.degree. to 50.degree. C.
The offset printing plate according to the present invention features a simple structure and a high mechanical strength. A tensile strength of a carbon steel substrate ranges from 32 to 36 kgf/mm.sup.2. Wear-resistance of the non-printing areas is about 0.05 mm.sup.3 /cm.sup.2. The offset printing plate according to the present invention can withstand press runs of about 250,000 prints.
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Belyaeva Julia I.
Guschina Izabella I.
Krikman Genrietta Y.
Krutikov Nikolai N.
Lapatukhin Veniamin S.
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