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
1999-04-12
2001-01-23
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
Reexamination Certificate
active
06177230
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a heat-hardenable composition, a heat-sensitive recording material and a planographic form plate using the composition. More specifically, the present invention relates to a heat-hardenable composition having excellent storage stability and hardenability, a heat-sensitive recording material utilizing the thermally cross-linkable property of the composition, particularly a heat-sensitive recording material capable of being used as a material for a planographic printing plate in a direct plate making process in which the material is directly inscribed by scanning an infrared laser, and a planographic form plate using the heat-sensitive recording material.
2. Description of the Related Art
Traditionally, the technology of a heat-hardenable resin, which can be cross-linked by the action of heat, is so versatile that it has been used in a variety of applications including the production of paints, ink, rubber, adhesives, and the like, textile processing in the field of textile materials, the production of sealing materials in the field of electronics related materials, and printing and resist production. As to materials for the traditional heat-hardenable resins and their application in ink, rubber, and adhesives, details are described in a number of textbooks. An example of the textbooks is “Handbook of cross-linking agents”, edited by S. Yamashita et al, Taiseisha Publishing Co., Ltd. (1981). Application of a heat-hardenable resin in printing is described in, for example, Japanese Patent Application Publication (JP-B) No. 45-23,519.
As to the application to photosensitive recording materials, solid-state and semiconductor lasers, which emit infrared light of wavelengths range from 760 to 1200 nm, are recently attracting attention as a recording light source in a system where plates are made directly from digital data of a computer, because these radiation sources, which have a high output power despite their small size, can be easily obtained. However, since the sensitivities of many practically useful photosensitive recording materials are limited to light in a visible light region of 760 nm or less, the above-mentioned infrared lasers cannot be used for image recording. Accordingly, there is a demand for an image recording material which can be recorded on by an infrared laser.
Meanwhile, an example of a negative-type image recording material, which can be inscribed for recording by such an infrared laser, is described in Japanese Patent Application Laid-Open (JP-A) No. 8-276,558. This recording material comprises a substance which generates heat by absorbing light, an alkali-soluble resin, and a specific phenol derivative which has 4~8 benzene nuclei in the molecule. The drawback of this recording material was that the sensitivity of the material to a laser was insufficient. Despite many proposals to increase the sensitivity of the recording material, the material has been associated with the problem that in general measures to increase sensitivity tend to impair the storage stability of the recording material, and in particular, the storage stability in highly humid conditions.
Accordingly, there has been a strong demand for a hardenable material as an image recording material which has superior storage stability especially in such applications as materials for a heat-sensitive planographic printing plate and the like.
SUMMARY OF THE INVENTION
It is accordingly an object of the present invention to provide a heat-hardenable composition which has excellent storage stability, particularly in conditions of high temperature and high humidity, and which is suited for use as a material for a heat-sensitive planographic form plate. Another object of the present invention is to provide a heat-sensitive recording material and a planographic form plate, which each have excellent storage stability, by using the heat-hardenable composition of the present invention.
After intense studies, the present inventors found that, when heated, a specific thermally reactive compound forms a reactive group, which reacts with a group capable of reacting therewith and present in the vicinity thereof, thus causing a cross-linking reaction which leads to a hardening phenomenon. Further, they found that the specific thermally reactive compound has excellent storage stability, too. Based on these findings, they have achieved the present invention.
Namely, the present invention provides a heat-hardenable composition which comprises a compound having two or more sulfonic acid ester groups each capable of releasing sulfonic acid by the action of heat. Preferably, the heat-hardenable composition of the present invention further comprises a compound having two or more groups each reactive with the group generated by thermal release of sulfonic acid. Preferably, the compound having two or more sulfonic acid ester groups each capable of releasing sulfonic acid by the action of heat contains the structure represented by the following general formula (1):
where L represents an organic group comprising polyvalent non-metallic atoms which is necessary for linking the structure represented by the general formula (1) to a polymer skeleton; and R
1
and R
2
each represent a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group.
Preferably, the group reactive with the group generated by thermal release of sulfonic acid is a functional group selected from the group consisting of a hydroxyl group, a carboxyl group, an amino group, an amido group, and a sulfonamide group.
And, preferably, the compound having two or more sulfonic acid ester groups, each capable of releasing sulfonic acid by the action of heat, has an alkali-soluble group in addition thereto.
Further, the present invention provides a heat-hardenable composition comprising a compound which has two or more sulfonic acid ester groups each capable of releasing sulfonic acid by the action of heat and which has two or more groups each reactive with the group generated by thermal release of sulfonic acid. Preferably, the compound, which has two or more sulfonic acid ester groups each capable of releasing sulfonic acid by the action of heat and which has two or more groups each reactive with the group generated by thermal release of the sulfonic acid, contains the structure represented by the general formula (1).
Preferably, the above-mentioned group, which is reactive with the group generated by thermal release of sulfonic acid, is a functional group selected from the group consisting of a hydroxyl group, a carboxyl group, an amino group, an amido group, and a sulfonamide group. And, preferably, the compound which, has two or more sulfonic acid ester groups each capable of releasing sulfonic acid by the action of heat and which has two or more groups each reactive with the group generated by thermal release of sulfonic acid, has an alkali-soluble group in addition thereto.
Preferably, the heat-hardenable composition of the present invention further contains a substance capable of converting infrared into heat.
Further, the present invention provides a planographic form plate comprising a substrate and an infrared light-sensitive layer provided thereon which layer is composed of the heat-hardenable composition of the present invention.
Still further, the present invention provides a sulfonic acid ester compound containing the structure represented by the general formula (2):
wherein R
3
represents a hydrogen atom, a chlorine atom, a methyl group, a methoxy group, or an acetoamide group.
The details of the hardening mechanism of the heat-hardenable composition of the present invention are not clear. However, some experimental results suggest that the following reactions will take place. That is, heating decomposes the sulfonic acid ester and generates a reactive site such as a carbocation. A nucleophilic reactant such as a cross-linking agent reacts with the reactive site to create a linkage. In this way, a hardening reaction will take place.
D
Baxter Janet
Burns Doane , Swecker, Mathis LLP
Fuji Photo Film Co. , Ltd.
Gilliam Barbara
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