Radiation imagery chemistry: process – composition – or product th – Imaging affecting physical property of radiation sensitive... – Radiation sensitive composition or product or process of making
Reexamination Certificate
2001-04-20
2004-02-10
Baxter, Janet (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Imaging affecting physical property of radiation sensitive...
Radiation sensitive composition or product or process of making
C430S270100, C430S286100, C430S271100, C430S302000, C430S907000, C430S905000, C430S910000
Reexamination Certificate
active
06689539
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a photosensitive composition and a photosensitive lithographic printing plate which utilizes the photosensitive composition, and in particular to a photosensitive lithographic printing plate with superior ink receptivity and with a photosensitive layer (image area) which displays superior film strength, or a photosensitive lithographic printing plate with superior ink receptivity and with a uniform coating film of photosensitive layer, or a photosensitive lithographic printing plate with superior ink receptivity and with a photosensitive layer (image area) which displays superior film strength, which can be developed by an alkali developing solution incorporating no organic solvents, as well as to photosensitive compositions for producing such photosensitive lithographic printing plates.
2. Description of the Related Art
Photosensitive lithographic printing plates are typically formed by providing a photosensitive layer comprising a photosensitive compound on the surface of a support such as aluminum, paper or plastic, which has undergone suitable surface treatment. Such photosensitive lithographic printing plates are manufactured by the application of a photosensitive composition, comprising a photosensitive compound which has been dissolved or dispersed in an organic solvent, to the surface of the support, followed by subsequent drying.
Photosensitive lithographic printing plates of this type, such as a negative lithographic printing plate using a diazo resin as the photosensitive compound, are generally used in the manner described below.
First, with a negative film or the like superimposed thereon, the photosensitive layer of a negative photosensitive lithographic printing plate is exposed to light, and the exposed areas undergo polymerization and/or cross linking, and become insoluble in the developing solution. The photosensitive lithographic printing plate is then developed, and the unexposed areas are eluted by the developing solution. In this manner, the areas insoluble in the developing solution are termed the image area, and repel water and receive the oil based ink, whereas the areas eluted by the developing solution are termed the non-image area, and receive water and repel the oil based ink.
However, in negative photosensitive lithographic printing plates which use diazo resins, the oil sensitivity of the image area is typically low and the ink receptivity at the start-up of printing is insufficient, leading to an increase in waste paper.
Techniques to improve the ink receptivity of negative photosensitive lithographic printing plates are already known, and include a method disclosed in Japanese Unexamined Patent Application, First Publication No. Sho-55-527 in which an oil sensitizer such as a half ester of a copolymer of styrene and maleic anhydride is added to the photosensitive composition.
However, this type of oil sensitizer is eluted from the photosensitive layer during developing, and suffers from being unable to display sufficient improvement in the ink receptivity. Furthermore, incorporating an oil sensitizer in the photosensitive layer causes other problems such as a reduction in the film strength of the photosensitive layer (the image area), and a reduction in the sensitivity of the photosensitive lithographic printing plate.
Furthermore, in order to realize the properties of the photosensitive composition in the photosensitive lithographic printing plate, it is necessary, during the application and drying of the photosensitive composition on the surface of the support, to ensure the formation of a uniform photosensitive layer on the support.
Photosensitive compositions disclosed in Japanese Unexamined Patent Application, First Publication No. Sho-62-170950 and Japanese Unexamined Patent Application, First Publication No. Sho-62-226143 aim to form a uniform photosensitive layer on a support, and propose photosensitive compositions which comprise, as a fluorine based surfactant, a polymer with a fluoro aliphatic group in which three terminal carbon atoms are well fluorinated, and a poly (oxyalkylene) group.
However, although these type of fluorine based surfactants improve the non-uniformity of the photosensitive layer, the uniformity of the photosensitive layer is still not always sufficient. Furthermore, because the poly (oxyalkylene) group is hydrophilic, there is an associated reduction in ink receptivity at the start-up of printing.
Photosensitive compositions disclosed in Japanese Unexamined Patent Application, First Publication No. Hei-1-18142 and Japanese Unexamined Patent Application, First Publication No. Hei-3-172849 aim to improve the ink receptivity in cases where a fluorine based surfactant is added, and propose photosensitive compositions which comprise, as the fluorine based surfactant, a polymer with a fluoro aliphatic group in which three terminal carbon atoms are well fluorinated, a poly (oxyalkylene) group, and either an aliphatic hydrocarbon group or a cyclic hydrocarbon group.
However, even though the ink receptivity improves, the improvement is not always sufficient, and the uniformity of the photosensitive layer is still insufficient.
Furthermore, in conventional negative photosensitive lithographic printing plates, binder resins in which functional groups with an acidic hydrogen atom, such as carboxyl groups or phenolic hydroxyl groups, have been introduced, are often used to improve the developability. In particular, in order to make development possible with alkali developing solutions which comprise no organic solvents, large numbers of these functional groups with acidic hydrogen atoms need to be introduced into the binder resin.
However, these functional groups with acidic hydrogen atoms are hydrophilic, and as a result, the sensitivity of the photosensitive lithographic printing plate and the film strength of the photosensitive layer (image area) are both reduced, and the ink receptivity at the start-up of printing also deteriorates.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a photosensitive lithographic printing plate with superior ink receptivity and with a photosensitive layer (image area) which displays superior film strength, and a photosensitive composition for producing such a photosensitive lithographic printing plate.
Furthermore, another object of the present invention is to provide a photosensitive lithographic printing plate with superior ink receptivity and with a uniform photosensitive layer, and a photosensitive composition for producing such a photosensitive lithographic printing plate.
Furthermore, yet another object of the present invention is to provide a photosensitive lithographic printing plate with superior ink receptivity and with a photosensitive layer (image area) which displays superior film strength which can be developed by an alkali developing solution incorporating no organic solvents, and a photosensitive composition for producing such a photosensitive lithographic printing plate.
As a result of in-depth investigations aimed at realizing the above objects, the inventors of the present invention discovered that by using a fluororesin having a fluoro aliphatic group and an ethylene based unsaturated group as an oil sensitizer, using a fluororesin having a fluoro aliphatic group, a poly (oxyalkylene) group, and an ethylene based unsaturated group as a fluorine based surfactant, and using a fluororesin having a fluoro aliphatic group, an ethylene based unsaturated group, and a functional group having an acidic hydrogen atom as an alkali soluble resin, the above objects could be achieved, and as a result completed the present invention.
In other words, a photosensitive composition of the present invention includes a fluororesin with a fluoro aliphatic group of 3 to 20 carbon atoms in which at least two of three terminal hydrogen atoms are substituted for fluorine atoms, and an ethylene based unsaturated group; as well as a negative photosensitive compound.
Furthermore, the afor
Hayashi Koji
Kamiya Masamichi
Komine Hirotaka
Makino Miyuki
Baxter Janet
Faegre & Benson LLP
Kodak Polychrome Graphics LLC
Lee Sin J.
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