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
2002-09-24
2004-10-05
Gilliam, Barbara (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
C430S278100, C430S281100, C430S286100, C430S302000, C430S309000, C430S434000, C430S494000, C430S944000, C430S945000
Reexamination Certificate
active
06800417
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a lithographic printing plate precursor for use in the negative-type image recording, more specifically, the present invention relates to a lithographic printing plate precursor capable of so-called direct plate-making where a printing plate can be produced directly from digital signals of a computer or the like by using an infrared laser.
BACKGROUND OF THE INVENTION
Conventionally, a negative-type photosensitive lithographic printing plate widely used is obtained by providing a negative-type photosensitive layer containing a diazo compound on an aluminum support subjected to a surface-roughening treatment, an alkali etching or an anodization treatment. The diazo compound is known to decompose upon exposure to generate an acid and accelerate the crosslinking reaction. When the photosensitive layer is developed with an alkali aqueous solution after image exposure, only the unexposed area is dissolved and removed and the support surface is revealed. The exposed part (image area) works out to an ink-receptive part due to remaining of the lipophilic photosensitive layer and the unexposed part (non-image area) works out to an ink-repellent part by holding water due to revealment of the hydrophilic support surface. However, the aluminum support surface is insufficient in the hydrophilicity and in turn in the ink repellency and this causes a problem that ink adheres to the non-image area (hereinafter called “staining performance”).
Accordingly, the non-image area must be usually rendered hydrophilic so as to improve the staining performance. However, if a negative-type photosensitive layer is provided on a hydrophilized support, the number of sheets which can be normally printed decreases due to poor adhesion between the hydrophilic support surface and the lipophilic photosensitive layer (hereinafter called “impression performance”) . To overcome this problem, usually, only the non-image area is hydrophilized at the development by using a developer containing a silicate such as sodium silicate or potassium silicate. However, use of a developer containing a silicate has a problem, for example, a solid matter ascribable to SiO
2
is readily precipitated or in the neutralization for treating the developer waste, a gel ascribable to SiO
2
is produced. Therefore, a technique of, even when a negative-type photosensitive layer is provided on an aluminum support, ensuring good adhesion between the support and the photosensitive layer and causing no deterioration of the impression performance has been demanded.
In order to solve these problems, U.S. Pat. No. 3,136,636 discloses a technique of providing an undercoat layer comprising a water-soluble polymer such as polyacrylic acid or carboxymethyl hydroxyethyl cellulose, however, the impression capability is not satisfied. Also, U.S. Pat. No. 4,483,913 discloses a technique of providing an undercoat layer comprising a quaternary ammonium compound such as poly(dimethyldiallylammonium chloride), however, the staining performance is not satisfied.
On the other hand, the laser technique is recently making a remarkable progress and particularly, as for the solid laser and the semiconductor laser of radiating an infrared ray at a wavelength of 760 to 1,200 nm, a high-output and compact laser is easily available. These lasers are very useful as a recording light source at the direct production of a printing plate from digital data of a computer or the like. However, many photosensitive recording materials useful in practice are sensitive to light in the visible light region at a wavelength of 760 nm or less and therefore, image recording cannot be performed with these infrared lasers. Accordingly, a material capable of recording with an infrared laser is being demanded.
SUMMARY OF THE INVENTION
The present invention has been made to overcome those problems in conventional techniques and achieve the following object. The object of the present invention is to provide a lithographic printing plate precursor which can produce a printing plate directly from digital data of a computer or the like by performing the recording using a solid or semiconductor laser of radiating an infrared ray and exhibits good properties in staining performance and impression performance.
As a result of extensive studies, the present inventors have found that the above-described can be attained by incorporating a specific compound into an interlayer between the support and the photosensitive layer (image-forming layer). The present invention has been accomplished based on this finding. Namely, the object of the present invention can be attained by the following lithographic printing plate precursor.
A lithographic printing plate precursor comprising an aluminum support having sequentially provided thereon an interlayer comprising a compound containing a divalent or greater valent metal element, and a photosensitive layer containing an infrared absorbent, a radical generator and a radical polymerizable compound, the aluminum support being surface-roughened and subjected to the formation of an anodic oxide coating (film).
DETAILED DESCRIPTION OF THE INVENTION
The present invention is described in detail below.
The lithographic printing plate precursor of the present invention is obtained by sequentially providing an interlayer comprising a compound containing a divalent or greater valent metal element, and a photosensitive layer containing an infrared absorbent, a radical generator and a radical polymerizable compound, on an aluminum support which is surface-roughened and subjected to the formation of an anodic oxide coating.
[I] Interlayer
In the present invention, an interlayer comprising a compound containing a divalent or greater valent metal element, preferably a di-, tri- or tetra-valent metal element, between the support and the photosensitive layer.
The compound containing a divalent or greater valent metal element, which is contained in the interlayer, indicates a compound containing as a positive component, for example, a metal element belonging to Groups 2, 3, 12 and 13 of the periodic table, preferably beryllium, magnesium, calcium, strontium, barium, zinc, cadmium, mercury, aluminum, gallium, indium, thallium, scandium or yttrium, and as a negative component, halogen element, nitric acid, sulfuric acid, acetic acid, phosphoric acid, hydrochloric acid, iodic acid, carbonic acid, oxygen acid, ethylenediamine tetraacetic acid, hydroxyl group, hydroxo group, hydroxyamino group, alkoxyl group, acetylacetone, or alkyl acetoacetate. Among these, preferred are compounds containing calcium, magnesium, strontium, barium or aluminum as the positive component. These components may be used individually or in combination of two or more thereof.
Specific examples of the compound containing calcium, magnesium, strontium, barium or aluminum as the positive component include calcium fluoride, magnesium fluoride, strontium fluoride, barium fluoride, aluminum fluoride, calcium chloride, magnesium chloride, strontium chloride, barium chloride, aluminum chloride, calcium bromide, magnesium bromide, strontium bromide, barium bromide, aluminum bromide, calcium iodide, magnesium iodide, strontium iodide, barium iodide, aluminum iodide, calcium hydroxide, magnesium hydroxide, strontium hydroxide, barium hydroxide, aluminum hydroxide, calcium nitrate, magnesium nitrate, strontium nitrate, barium nitrate, aluminum nitrate, calcium sulfate, magnesium sulfate, strontium sulfate, barium sulfate, aluminum sulfate, alum, calcium acetate, magnesium acetate, strontium acetate, barium acetate, aluminum acetate, calcium ethylenediaminetetraacetate, magnesium ethylenediaminetetraacetate, strontium ethylenediaminetetraacetate, barium ethylenediaminetetraacetate, calcium phosphate, magnesium phosphate, strontium phosphate, barium phosphate, calcium carbonate, magnesium carbonate, strontium carbonate, barium carbonate, aluminum methylate, aluminum ethylate, aluminum isopropylate, aluminum mono-sec-butoxy diisopropylate, aluminum secbutylat
Fuji Photo Film Co. , Ltd.
Gilliam Barbara
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