Image forming material and image forming method

Details Image forming material and image forming method Image forming material and image forming method

1996-10-15

2002-05-21

Dote, Janis L. (Department: 1753)

Radiation imagery chemistry: process, composition, or product th

Diazo reproduction, process, composition, or product

Composition or product which contains radiation sensitive...

C430S270100, C430S926000, C430S944000

Reexamination Certificate

active

06391512

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates to an image forming material comprising a so-called positive working light sensitive layer to be solubilized by an active light radiation and an image forming method employing the same, and particularly to an image forming material, for example, a positive working presensitized planographic printing plate, capable of forming an image by an infrared light such as a semiconductive laser and an image forming method employing the same.
BACKGROUND OF THE INVENTION
As a positive working light sensitive layer to be solubilized by an active light radiation a light sensitive layer containing an acid generating compound and an acid decomposable compound is known. A light sensitive composition containing a compound having an orthocarboxylic acid or carboxylic acid amide acetal group is disclosed in U.S. Pat. No. 3,779,779, a light sensitive composition containing a compound having an acetal or a ketal in the main chain is disclosed in Japanese Patent O.P.I. Publication No. 53-133429/1978, and a light sensitive composition containing a compound having a silylether group is disclosed in Japanese Patent O.P.I. Publication No. 65-37549/1985. These compounds have sensitivity in the ultraviolet range and those capable of being solubilized by ultraviolet radiation, and can not give an image by irradiation of an infrared light such as a cheap and compact semiconductor laser.
As a technique giving an image by irradiation of an infrared light such as a semiconductor laser, a light sensitive layer containing an acid generating compound, a resol resin, a novolak resin and an infrared absorber is disclosed in compound capable of generating an acid on radiation of an active light is disclosed in U.S. Pat. No. 5,340,699, which gives a negative image by imagewise exposing, heating and developing and a positive image by imagewise exposing and then developing without heating. However, in this technique, the negative image forming method requires additional heating process incovenient to users and imposes much electric power consumption, and on the other hand, the positive image forming method has the disadvantages that stains occur in non-image portions due to poor development, a part of the image portions is dissolved in a developer. Further, storage stability of an image forming material comprising this light sensitive layer is not satisfactory.
SUMMARY OF THE INVENTION
An object of the invention is to provide a positive working image forming material capable of giving an image by irradiation of infrared rays and an image forming method employing the same.
Another object of the invention is to provide to provide a positive working image forming material containing an acid generating compound and an acid decomposable compound which is capable of giving an image by irradiation of infrared rays and an image forming method employing the same.
Still another object of the invention is to provide a positive working image forming material having high sensitivity to infrared rays and excellent developability and storage stability and an image forming method employing the same.
DETAILED DESCRIPTION OF THE INVENTION
The above object of the invention can be attained by the following:
(1) An image forming material comprising a support and provided thereon, a light sensitive layer containing a compound capable of generating an acid on irradiation of an active light, a compound having at least one chemical bond capable of being decomposed by an acid and an infrared absorber,
(2) The image forming material of (1) above, wherein the compound capable of generating an acid is an organic halogen containing compound,
(3) The image forming material of (1) above, wherein the compound having at least one chemical bond capable of being decomposed by an acid is a compound having a —(CH
2
CH
2
O)
n
— in which n is an integer of 2 to 5,
(4) The image forming material of (1) above, wherein the compound having at least one chemical bond capable of being decomposed by an acid is a compound represented by the following formula (1):
 Wherein m and n independently represent an integer of 1 to 5; R, R′ and R″ independently represent a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, an alkoxy group, a hydroxy group, a sulfo group or its salt group or a carboxyl group or its salt group; and p, q and r independently represent an integer of 1 to 3,
(5) The image forming material of (1) above, wherein the infrared absorber is a cyanine dye represented by the following formula (2):
wherein Z
1
represents a sulfur, selenium, oxygen atom or C (R
3
) (R
4
) in which R
3
and R
4
independently represent a hydrogen atom, a halogen atom or an alkyl group having 1 to 3 carbon atoms; Z
2
represents a sulfur, selenium, oxygen atom or C (R
5
) (R
6
) in which R
5
and R
6
independently represent a hydrogen atom, a halogen atom or an alkyl group having 1 to 3 carbon atoms; X
1
and X
2
independently represent an atomic group necessary to form a benzene ring or a condensed ring; R
1
and R
2
independently represent a substituent, provided that one of R
1
and R
2
represents an anion; and L represents a conjugated bond chain having 5 to 13 carbon atoms.
(6) The image forming material of (1) through (5) above, wherein the light sensitive layer further comprises a novolak resin and a nonionic surfactant,
(7) The image forming material of (1) through (5) above, wherein the light sensitive layer further comprises a novolak resin and an acryl resin, or
(8) An image forming method comprising the steps of imagewise exposing the image forming material of (1) through (7) above to a visible or infrared light having a wavelength of 700 nm or more; and removing the exposed portions with an alkaline developer.
The present invention will be detailed below.
The compound (hereinafter referred to as the acid generating compound of the invention) capable of generating an acid on irradiation of an active light used in the light sensitive layer of the invention includes various conventional compounds and mixtures. For example, a salt of diazonium, phosphonium, sulfonium or iodonium ion with BF
4
−
, PF
6
−
, SbF
6
−
SiF
6
2−
or ClO
4
−
, an organic halogen containing compound, o-quinonediazide sulfonylchloride or an organic metal is a compound capable of generating or releasing an acid on irradiation of an active light and can be used as the acid generating compound of the invention. The organic halogen containing compound known as an photoinitiator capable of forming a free radical forms a hydrogen halide and can be used as the acid generating compound of the invention.
The examples of the organic halogen containing compound capable of forming a hydrogen halide include those disclosed in U.S. Pat. Nos. 3,515,552, 3,536,489 and 3,779,778 and West German Patent No. 2,243,621, and compounds generating an acid by photodegradation disclosed in West German Patent No. 2,610,842.
Further, 2-halomethyl-1,3,4-oxadiazole compound, for example, 2-trichloromethyl-5-[&bgr;(2-benzofuryl)vinyl]-1,3,4-oxadiazole can be used. The examples of the acid generating compounds of the invention include those disclosed in Japanese Patent O.P.I. Publication No. 56-17345/1981.
The o-naphthoquinone diazide-4-sulfonylhalogenide disclosed in Japanese Patent O.P.I. Publication No. 50-36209/1975.
In the invention the organic halogen containing compound is preferable for an acid generating compound in view of sensitivity to infrared rays or storage stability of an image foming material using it. In the organic halogen containing compound, triazines or oxadiazoles having a halogen-substituted alkyl group are preferable, and triazines having a halogen-substituted alkyl group are especially preferable.
The examples of the oxadiazoles having a halogen-substituted alkyl group include a 2-halomethyl-1,3,4-oxadiazole compound disclosed in Japanese Patent O.P.I. Publication Nos. 54-74728/1979, 55-24113/1980, 55-77742/1980, 60-3626/1985 and 60-138539/1985. Of these compounds, 2-trichloro

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