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
2001-06-04
2004-04-27
Kelly, Cynthia H. (Department: 1774)
Radiation imagery chemistry: process, composition, or product th
Imaging affecting physical property of radiation sensitive...
Radiation sensitive composition or product or process of making
C430S269000, C430S302000, C428S195100
Reexamination Certificate
active
06727037
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a positive or negative image-formation material which can be recorded image-wise by exposure to an infrared laser and in which solubility of a recording layer at exposed portions changes, and to an infrared absorber which can be suitably used in the image-formation material. More particularly, the present invention relates to an image-formation material with an infrared layer, which can be recorded by exposure to an infrared laser or the like in the near-infrared range, and particularly which is suitable for a planographic printing plate used for so-called direct plate formation which can provide plate formation directly from digital signals of computers and the like, and to an infrared absorber having a surface orientation group, which absorber is suitable for application in the image-formation material.
2. Description of the Related Art
Recently, with the development of solid lasers and semiconductor lasers having an emitting region in near-infrared to infrared ranges, systems using infrared lasers and providing direct plate formation from digital data of computers have drawn attention.
JP-A No. 7-285275 discloses a positive-type planographic printing material for infrared lasers used in direct plate formation. This invention is an image-recording material obtained by adding to an alkaline aqueous solution-soluble resin a substance which absorbs light and generates heat, and a positive photosensitive compound such as a quinonediazide compound or the like. The positive photosensitive compound acts in image portions as a solution inhibitor that substantially decreases solubility of the alkaline aqueous solution-soluble resin, and is decomposed in non-image portions by heat, leading to a loss of solution-inhibiting ability. Resultantly, the positive photosensitive compound can be removed by development, to form an image.
On the other hand, it is known that onium salts and alkali-insoluble compounds which can form hydrogen bonds act to suppress alkali-solubility of an alkali-soluble polymer. Regarding an image-formation material for infrared lasers, WO97/39894 describes that a composition using a cationic infrared absorber as an agent to suppress dissolution of an alkaline water-soluble polymer shows a positive action. This positive action is such that an infrared absorber absorbs laser light and an effect of suppressing dissolution of a polymer film at irradiated portions is reduced by generated heat, to form an image.
Further, as a method for forming negative images, there is a recording method in which a polymerization reaction is allowed to occur using, as an initiator, radicals generated by light or heat. The reaction cures a recording layer at exposed portions, forming image portions. Regarding such printing plates having a recording layer which is polymerized by light or heat, there are known technologies using, as a photosensitive layer, photo-polymerizable or heat-polymerizable compositions as described in JP-A Nos. 8-108621 and 9-34110.
Regarding image-forming properties of the above-mentioned various recording materials, there is a problem in that, although energy sufficient for an image formation reaction is obtained at the surface of a sensitive material irradiated by a laser, thermal diffusion to a substrate is extensive, due to excellent thermal diffusion, and particularly due to excellent heat conductivity when a generally-used aluminum substrate is used as the substrate. Consequently, energy is not sufficiently utilized for forming images, leading to low sensitivity. With this problem, a sufficient effect of reducing suppression of dissolution or an effect of promoting a reaction by polymerization may not be obtained in deep portions of the sensitive material. Consequently, the occurrence of alkali development at exposed portions
on-exposed portions may not be fully realized, such that excellent images cannot be obtained, and furthermore, developing latitude, that is, tolerable range which can afford good image-formation when concentration of an alkaline developing solution is varied, is narrow.
SUMMARY OF THE INVENTION
Therefore, an object of the present invention is to provide an image-formation material having high sensitivity and excellent image-forming property, and a novel infrared absorber which can be suitably used in this material.
The present inventor has intensively studied for the purpose of improving sensitivity and image-forming property of image-formation materials, and has consequently found that both sensitivity and image-forming property can be improved by using an infrared absorption agent having a specific substituent. Further, the inventor has found a novel infrared absorber that can be suitably used in this agent, leading to completion of the present invention.
That is, the image-formation material of the present invention is a heat mode-applicable image-formation material, the image-formation material having: a substrate; and an image-formation layer on the substrate which contains an infrared absorption agent having at least one surface orientation group in a molecule thereof, solubility of the image-formation layer in an alkaline aqueous solution being changeable by action of near-infrared range radiation.
Here, in a preferable embodiment, the above-mentioned infrared absorption agent is an infrared absorber having at least one surface orientation group selected from fluorine-containing substituents and long chain alkyl groups.
Further, the infrared absorber of the present invention is characterized in that it has in the molecule a fluorine-containing substituent having at least 5 fluorine atoms.
As the infrared absorber having such a fluorine substituent, there are specifically exemplified infrared absorbers which manifest absorption in the near-infrared range, represented by the following general formulae (1) to (3).
In general formula (1): each of R
F
1
and R
F
2
independently represents a fluorine-containing substituent having at least 5 fluorine atoms; each of X
1
and X
2
independently represents —CR
9
R
10
—, —S—, —Se—, —NR
11
—, —CH═CH— or —O—. R
1
to R
8
each independently represents a hydrogen atom, alkyl group, alkoxy group or halogen atom. R
1
to R
8
may represent a plurality of atoms such that at least one of pairs R
1
and R
3
, R
2
and R
4
, R
5
and R
7
, R
6
and R
8
, R
1
and X
1
, or R
2
and X
2
can be mutually connectable to form an aliphatic 5-membered ring or 6-membered ring, an aromatic 6-membered ring or a substituted aromatic 6-membered ring.
R
9
and R
10
each independently represents an alkyl group, or represent ═CH— which are combined to form a ring; R
11
represents an alkyl group.
Z
1
represents a heptamethine group, which may have one or more substituents selected from alkyl groups, halogen atoms, amino groups, arylthio groups, alkylthio groups, aryloxy groups, alkoxy groups, barbituric groups and thiobarbituric groups, and which may include a cyclohexene or cyclopentene ring formed by mutually bonding substituents on two methine carbons of the heptamethine group, which ring may further have a substituent selected from alkyl groups and halogen atoms.
X
−
represents a counter ion necessary for neutralizing an electric charge.
In general formula (2): R
F
3
represents a fluorine-containing substituent having at least 5 fluorine atoms. X
3
represents —NH—, —O— or —S—. Each of R
12
and R
13
independently represents an alkyl group. These alkyl groups may have a substituent, and as preferable substituents, aryl groups such as a phenyl group, toluyl group and the like, alkoxy groups such as a methoxy group, ethoxy group, methoxyethoxy group and the like, aryloxy groups such as a phenoxy group, toluyloxy groups and the like, acid groups such as a carboxyl group, sulfonic group and the like or salts thereof, quaternary ammonium groups such as a triethylammonium group, tributylammonium group and the like, a hydroxyl group, amide groups and the like are exemplified.
X
1
, X
2
, R
1
to R
8
and X
Burns Doane Swecker & Mathis L.L.P.
Ferguson L.
Fuji Photo Film Co. , Ltd.
Kelly Cynthia H.
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