Radiation imagery chemistry: process – composition – or product th – Diazo reproduction – process – composition – or product – Composition or product which contains radiation sensitive...
Reexamination Certificate
2000-05-16
2002-09-17
Chu, John S. (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Diazo reproduction, process, composition, or product
Composition or product which contains radiation sensitive...
C430S192000, C430S193000, C534S558000
Reexamination Certificate
active
06451497
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention generally relates to a positive photosensitive composition having photosensitivity in the infrared wavelength range, and more particularly to a positive photosensitive composition that is suitable for lithographic photoresists or printing material for what is referred to as direct plateable positive lithography, which allows plates to be directly produced using an infrared laser based on digital signals from a computer or the like.
2. Description of the Related Art
Laser development has been quite remarkable recently. Solid-state lasers and semiconductor lasers in particular, which emit infrared rays having a wavelength ranging from 760 to 1200 nm (hereinafter referred to as “infrared lasers”), are now readily available in the form of small-scale models with high output. Such infrared lasers are extremely useful as printing light sources during the direct production of printing plates based on digital data from computers and the like. There has thus been increasing demand recently for materials that can be used as image recording materials, particularly heat mode laser image recording materials, with high sensitivity for such infrared printing light sources.
Typical examples of positive image recording materials for heat mode lasers include printing materials featuring the use of quinone diazides or diazonium salts such as those disclosed in Japanese Patent Application Laid-Open (JP-A) No.7-285275. Such positive image recording materials utilize dissolution inhibiting effects brought about by the interaction between quinone diazides or diazonium salts, infrared absorbents, and alkaline water-soluble polymers. The quinone diazides or diazonium salts are decomposed upon exposure to laser light, breaking down this interaction, and the parts that are exposed to light are dissolved in alkaline water during development to form positive images. The desired dissolution of the quinone diazides or diazonium salts referred to here means dissolution whereby acid is produced upon reaction with moisture in the system. The acid that is produced facilitates development.
Heat mode exposure systems do not have as much system moisture as UV exposure systems, however, and are thus incapable of producing enough acid from quinone diazides or diazonium salts. One problem, for example, is that the interaction between the infrared absorbent and alkaline water-soluble polymer is restored when allowed to stand for several hours after light exposure, resulting in lower sensitivity and incapacitated development.
As noted above, it has not been possible in the past to obtain a positive photosensitive composition with high sensitivity to heat mode lasers, good development latitude, and good storage stability.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a positive photosensitive composition with high sensitivity to heat mode lasers, good development latitude, and good storage stability.
As a result of extensive research, the inventors perfected the present invention upon finding that the aforementioned drawbacks can be resolved by the following means.
Specifically, the positive photosensitive composition of the present invention comprises at least a diazo compound represented by the following General Formula 1, and a water-insoluble but alkaline water-soluble polymer:
(where Z represents an organic group in which the pKa of dissociating H in Ph—NH—Z is 14 or less; and Q
1
and Q
2
represent organic groups, where Q
1
and Q
2
may be bonded to form an aliphatic ring or aromatic ring).
The organic group z referred to here is preferably —SO
2
R
1
or —COR
2
(where R
1
represents a hydrocarbon group, and R
2
represents a hydrocarbon group with an electron-attracting substituent), and the hydrocarbon group R
2
preferably has any electron-attractive substituent selected from the group consisting of halogen atoms, substituted sulfonyl groups, nitro groups, cyano groups, alkoxy groups, and hydroxy groups.
The positive photosensitive composition of the present invention also preferably further comprises an infrared absorbent.
It is assumed that the development properties during exposure are not improved very much in conventional positive image recording materials for heat mode lasers because the quinone diazides or diazonium salts contained in the material produce intermediates that are highly reactive during exposure-induced decomposition, and that the intermediates become insoluble upon reaction with the alkaline water-soluble polymer serving as the binder.
For example, the naphthoquinone diazide used in positive image recording materials with UV exposure produce highly reactive ketenes when decomposed upon exposure. In UV light systems, the ketenes react with moisture in the material and are inactivated in the form of carboxylic acids, but it is assumed that the elevated heat in heat mode systems results in less moisture in the material and prevents the ketenes from reacting with water molecules, and that these ketenes react with the alkaline water-soluble polymer, rendering the alkaline water-soluble polymer insoluble.
A feature of the positive photosensitive composition of the present invention is the use of a diazo compound represented by the aforementioned General Formula 1 as an acid-producing agent. Because of its inherent structure, the diazo compound is believed to selectively react with water molecules to facilitate development during exposure, without producing ketenes that are highly reactive with alkaline water-soluble polymers when decomposed upon exposure.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The positive photosensitive composition of the present invention is described in detail below.
(A) Diazo Compounds Represented by General Formula 1
The diazo compounds of the present invention are characterized by being represented by the following General Formula 1.
In General Formula 1, Z represents an organic group selected so that the pKa of the dissociating hydrogen in compound Ph—NH—Z, where the amino group of Ph—NH
2
is substituted by Z, is 14 or less. The organic group Z is not particularly limited, provided that it meets these conditions, although —SO
2
R
1
and —COR
2
(where R
1
represents a hydrocarbon group, and R
2
represents a hydrocarbon group with an electron-attracting substituent) are particularly preferred.
The hydrocarbon group R
1
of the organic group —SO
2
R
1
may have a substituent, and may include an unsaturated bond. Examples of such hydrocarbon groups include alkyl groups, substituted alkyl groups, aryl groups, substituted aryl groups, alkenyl groups, substituted alkenyl groups, alkinyl groups, and substituted alkinyl groups.
Examples of alkyl groups include C
1
to C
20
linear, branched, or cyclic alkyl groups, specific examples of which include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, hexadecyl, octadecyl, eicosyl, isopropyl, isobutyl, sec-butyl, tert-butyl, isopentyl, neopentyl, 1-methylbutyl, isohexyl, 2-ethylhexyl, 2-methylhexyl, cyclohexyl, cyclopentyl, and 2-norbornyl groups. Of these, C
1
to C
12
linear alkyls, C
3
to C
12
branched alkyls, and C
5
to C
10
cyclic alkyls are preferred.
Substituted alkyl groups are composed by a bond between the substituent and alkylene group. Monovalent nonmetallic atom groups except for hydrogen are used as substituents. Preferred examples include halogen atoms (—F, —Br, —Cl, —I), hydroxy groups, alkoxy groups, aryloxy groups, mercapto groups, alkylthio groups, arylthio groups, alkyldithio groups, aryldithio groups, amino groups, N-alkylamino groups, N,N-dialkylamino groups, N-arylamino groups, N,N-diarylamino groups, N-alkyl-N-arylamino groups, acyloxy groups, carbamoyloxy groups, N-alkylcarbamoyloxy groups, N-arylcarbamoyloxy groups, N,N-dialkylcarbamoyloxy groups, N,N-diarylcarbamoyloxy groups, N-alkyl-N-arylcarbamoyloxy groups, alkylsulfoxy groups, arylsulfoxy groups, acylthio groups, acylamino groups, N-alkylacylamino groups, N-arylacylamino groups, ure
Burns Doane , Swecker, Mathis LLP
Chu John S.
Fuji Photo Film Co. , Ltd.
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