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
2000-07-11
2003-12-30
Hamilton, Cynthia (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
C430S156000, C430S271100, C430S944000
Reexamination Certificate
active
06670098
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a photosensitive or heat-sensitive image forming material.which can be used as a planographic printing plate material, a color proof, a photoresist, or a color filter. More specifically, the present invention relates to a negative-type or positive-type photosensitive or heat-sensitive image forming material, usable as a plate material for planographic printing, which enables so-called direct plate making in which a plate can be formed directly by scanning an infrared laser based on digital signals from a computer or the like.
2. Description of the Related Art
The development of lasers in recent years has been remarkable. In particular, high-output, compact solid-state lasers and semiconductor lasers (hereinafter occasionally referred to as “infrared lasers”) emitting infrared rays with wavelengths ranging from 760 nm to 1200 nm have become readily available. These infrared lasers are very useful as a recording light source when a printing plate is formed directly based on digital data from a computer or the like. Accordingly, there has been a growing demand in recent years for a photosensitive resin composition which has high sensitivity to such infrared recording light sources. Namely, a photosensitive resin composition in which a photochemical reaction or the like occurs when the photosensitive resin is irradiated with an infrared ray so that the solubility in a developing solution greatly changes has been desired.
Extensive studies have been made of recording materials sensitive to these kinds of laser light. Typical examples of materials which are recordable by an infrared laser having a wavelength of 760 nm or greater include the positive-type recording material described in U.S. Pat. No. 4,708,925 and the negative-type recording material which is crosslinked by an acid catalyst and described in Japanese Patent Application Laid-Open (JP-A) No. 8-276558.
Examples of recording materials sensitive to ultraviolet light or visible laser light having wavelengths ranging from 300 nm to 700 nm include many materials such as negative-type recording materials which are of a radical polymerization type and described in, for example, U.S. Pat. No. 2,850,445 and Japanese Patent Application Publication (JP-B) No. 44-20189. Although higher levels of sensitivity of such recording materials which utilize radical polymerization can be achieved, there has been the problem that the level of sensitivity is greatly reduced due to the polymerization being inhibited by oxygen.
All of these image forming materials are structured of a single-layered recording layer having a single composition, which recording layer is formed on a support such as aluminum or the like. In a single-layered recording layer having a uniform composition, because of the influence of a photosensitive substance or the like, the effect of the energy ray from a light source tends to decrease as the depth from the photosensitive layer surface toward the support becomes larger, so that the effect becomes a minimum in the vicinity of the boundary surface with the support. This tendency becomes even more pronounced if infrared rays are used for exposure because of the problem of heat diffusion to the reverse surface of the support.
In order to ease this tendency, a measure to increase the sensitivity of the recording layer itself can be taken. However, since an extreme increase in the sensitivity leads to a decline in storage stability in a highly humid environment and presents problems in actual use, there has been a demand for an image forming material which results in high image quality and has excellent storage stability.
A material recordable by an electron beam or short-wave light having wavelengths of 300 nm or less, is important as a photoresist material in particular. In recent years the degree of integration in integrated circuits has increasingly risen, and even in the manufacture of semiconductor substrates such as ultra LSIs and the like, it has become necessary to form ultra-fine patterns having line widths of a half micron or less. In order to satisfy this need, wavelengths used in exposure apparatuses used for photolithography have become increasingly shorter. Far ultraviolet light and excimer light (XeCl, KrF, ArF, and the like) have come to be studied. Further, ultra-fine patterning by an electron beam has come to be studied. In particular, electron beams are believed to be promising as light sources in next-generation patterning technology.
An object common to all of these image forming materials has been how to clarify image ON-OFF, namely how to clarify the portions irradiated and unirradiated (i.e., image portions and non-image portions) with the above-mentioned energies. In relation to this point, with regard to the aforementioned recording layer having a single composition, for example, problems arise due to insufficient adhesion between the support and the image portions in the case of a negative-type image recording material, and film remaining on the support due to insufficient developability in image portions in the case of a positive-type image recording material. Since these problems have not been satisfactorily solved, a new technology different from conventional technologies has been sought.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a photosensitive or heat-sensitive image forming material which can be formed directly from digital data from a computer or the like by using a solid-state laser or semiconductor laser emitting infrared rays, and which has excellent image adhesion in the case of a negative-type and leaves no film in non-image portions on the support in the case of a positive-type and which can produce high-quality images and has excellent storage stability.
As a result of their extensive studies of the layer structure of recording layers in image forming materials, the present inventors discovered that when a recording layer having ordinary sensitivity is provided in the vicinity of the surface to be exposed, by disposing a recording layer having an even higher level of sensitivity to an exposing light source between the former recording layer and a support, a high-quality image recorded by an infrared laser can be formed, and the problem of storage stability can be solved. The inventors therefore devised the present invention.
That is, the first aspect of the present invention is an image forming material, comprising(a) a support, (b) a recording layer disposed on the support, the recording layer including at least one composition having a solubility in water or an alkali aqueous solution that is changed when subjected to light or heat, and (c) an intermediate layer disposed between the support and the recording layer, having the same function as that of the recording layer but whose sensitivity to light or heat is higher than that of the recording layer. Further, the second aspect of the present invention is a method of making an image forming material, comprising the steps of (a) providing a support, (b) disposing an intermediate layer on the support, which includes a first substance having a solubility in water or an alkali aqueous solution that changes when subjected to light or heat, and (c) disposing a recording layer on the intermediate layer, which includes a second substance having a solubility in water or an alkali aqueous solution that changes when subjected to light or heat, and having a smaller sensitivity than that of the first substance.
The action of the image forming material of the present invention is not altogether clear. However, in the image forming material of the present invention, by disposing a layer, having the same function as that of the recording layer but an even higher level of sensitivity, as an intermediate layer between the support and the recording layer, changes in physical properties in the vicinity of the boundary surface with the support can be amplified. Thus, so-called high image quality (a high level of adhesion in the case
Fuji Photo Film Co. , Ltd.
Hamilton Cynthia
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