Kodak Polychrome Graphics, Gmbh

Gareth Rhodri Parsons

Kevin Barry Ray

Christopher David McCullough

David Stephen Riley

John David Riches

Richard David Hoare

Anthony Paul Kitson

Alan Stanley Monk

Alan Stanley Victor Monk

Peter Andrew Reath Bennett

Deborah Jane Firth

Alison Jane Brooks

James Laurence Mulligan

Mark John Spowage

Carole-Anne Smith

Stuart Bayes

Eduard Kottmair

John Andrew Hearson

Martyn Lott

Ken Shimazu

Colin Shoesmith

Imageable articles comprising positive working polymeric coatings on substrates are given a heat treatment as part of their manufacture, notably at a moderate temperature for an extended period. This heat treatment improves the development characteristics of the coatings in use. It has been found that by carrying out the heat treatment on articles wrapped in a water-impermeable material or in a humidity-enhanced oven, development characteristics may be further improved, especially adjacent to the edges of articles. The imageable articles include precursors for lithographic printing plates and for printed circuits.

Articles having imagable coatings

A method of making a mask or an electronic part, for example a printed circuit, comprises the steps of delivering heat in a desired pattern to a precursor of the mask or electronic part, the precursor comprising a surface coated with a coating, the coating comprising a heat-sensitive composition itself comprising an aqueous developer soluble polymeric substance and a compound which reduces the aqueous developer solubility of the polymeric substance, wherein the aqueous developer solubility of the composition is not increased by incident UV radiation but is increased by the delivery of heat; then developing the precursor to remove the heat-sensitive composition in regions to which the heat was delivered. In the case of a printed circuit precursor the surface may be then etched in conventional manner to yield the required printed circuit.

Method of making masks and electronic parts

Pattern formation

Thermally imageable lithographic printing plate precursors and heat-sensitive compositions for use in these printing plate precursors are disclosed. The compositions contain an aqueous developer soluble polymer, such as a phenolic resin; a compound that reduces the aqueous developer solubility of the polymer; and optionally, and infrared absorber. Examples of compounds that reduce the aqueous developer solubility of the polymer are those that contain at least one quarternized nitrogen atom, such as quinolinium compounds, benzothiazolium compounds, pyridinium compounds, and imidazoline compounds. On thermal imaging, the irradiated areas become more soluble in the aqueous developer and can be removed to form a positive image.

Lithographic printing forms

Phenolic resin compositions formulated for use in lithographic exposure processes are given a heat treatment at 40-90&deg; C. for at least 4 hours shortly after their coating onto lithographic substrates, to produce lithographic printing forms. It is found that such a heat treatment improves later exposure processes, in particular by rendering the sensitivity of the compositions less variable, over time.

Manufacture of lithographic printing forms

A heat imagable article has, in a single layer polymeric coating or in an inner layer of a multi-layer polymeric coating on a substrate, a polymeric matrix material, for example a phenolic resin, and, dispersed therein, polymeric particles, for example of polyethylene or polytetrafluoroethylene. The coating may contain a radiation absorbing compound so that suitable electromagnetic radiation, preferably infra-red radiation, may be used to heat the coating imagewise. The presence of the particles increases the physical robustness of the layer.

There is described a method of preparing a lithographic plate which comprises coating on a lithographic support having a hydrophilic surface a layer of a radiation sensitive coating, imaging the coating then acting on the plate while on the press with aqueous fount solution to remove the unexposed areas of the coating, to reveal the hydrophilic surface of the plate and to leave an ink receptive image, wherein the radiation sensitive coating comprises a diazo salt of formula (I):

Lithographic plate precursor

Relation to lithographic printing forms

There is described a method of preparing a lithographic plate which comprises coating on a lithographic support having a hydrophilic surface, a layer of a heat sensitive coating, digitally imaging the coating, then processing the plate with water to remove the unexposed areas of the coating to reveal the hydrophilic surface of the plate and to leave an ink receptive image, wherein the heat sensitive coating comprises a diazo salt of formula (I):

A lithographic printing plate precursor comprising on a support a radiation sensitive composition which comprises (1) a novolac resin, (2) a condensing agent for the novolac resin which is either a methylol polyvinyl phenol compound or a bishydroxymethyl compound, (3) a radiation sensitive latent acid generating compound, and (4) an infra-red sensitizing dye.

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West Yorkshire, United Kingdom

Gareth Rhodri Parsons