JPH11180048A - Image recording medium, and image recording method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image recording medium and an image recording method wherein a recording by a low output laser is possible at a high sensitivity, and a separate image receiving sheet is not required, and a retention stability is excellent. SOLUTION: For this image recording method, an image is recorded by using an acid generator which generates acid by the action of heat or an acid and is represented by formula AOP [In the formula, A indicates an acid residue represented by AOH, and P indicates an acid-sensitive substituent which can be desorbed at a temperature of 150 deg.C or lower by being catalyzed by AOH.], and an image recording medium containing a compound which generates a change in an absorption region of 360-900 nm by a reaction in particle, or a reaction between particles due to the action of an acid.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chemically amplified image recording medium having high sensitivity and good storability utilizing a color forming (or decoloring) reaction accelerated by an acid catalyst, and an image recording method using the same. It is about.

[0002]

2. Description of the Related Art A heat-sensitive recording material expresses an image area and a non-image area as a temperature difference distribution. Many schemes have been devised, such as changes in optical properties. This type of thermal recording medium is widely used as an output material for various printers, word processors, facsimile machines, etc. because of its advantages that a recorded image can be obtained by a dry and simple system and that it is maintenance-free. In recent years, with the progress of laser recording devices, applications to optical disks and plate making materials are being studied.

Conventionally, silver halide photographic materials requiring wet processing have been used as plate making materials. However, due to the demand for simplification of processing steps and the problem of environmental pollution caused by processing solutions, development of dry processing has been required. Desirably, several technical proposals have been made in recent years using the thermal recording method. From the viewpoint of resolution, image recording using a laser is preferable. For example, a method called dye ablation using a high-power laser has been developed.
164755, 7-149063, 7-14
No. 9065 and the like, an image forming apparatus is disclosed in JP-A-8-48053.
And No. 8-72400.

In this system, a recording material having a dye composition comprising an image dye coated on a support, a substance having absorption in a laser wavelength range (infrared absorbing substance) and a binder is irradiated with laser from the dye layer side. Thus, image recording is performed. The energy provided by the laser causes a sharp local change in the imaging layer at the spot where the laser beam hits the material, thereby driving the material out of the layer. According to the above patent publication, this is not a complete physical change (e.g., melting, evaporation or sublimation), but some kind of chemical change (e.g., bond breaking), rather than partial image dye removal. , It is a complete removal. In such a dye ablation method, a high-power laser is indispensable in order to increase the efficiency of removing the dye at the laser exposure site, and a dust collector is required to collect the removed dye. there were.

As a method that does not require a dust collector, a description of an ablation transfer type image recording method using a laser as a heat source is disclosed in US Pat. No. 5,171,650 and the like. In this system, a dye donor sheet containing a dynamic release layer overcoated with an ablative carrier topcoat is used, and the image is transferred to another adjacently aligned receiving sheet. For this reason, there has been a problem in that unnecessary sheets after image recording become waste materials. Also in this case, a high-output laser was indispensable to enhance the transfer efficiency. As described above, the conventional thermal recording method using laser ablation requires a high-output laser, and has a problem that dust and waste materials cannot be avoided.

On the other hand, as a thermal recording method using laser and not involving ablation, a system called "dry silver" has been developed in Japanese Patent Laid-Open No. Hei 6-1947.
No. 81, etc. In this system, laser recording is performed on a recording material containing a silver source that can be thermally reduced, a reducing agent for silver ions, and a photothermal conversion dye. This was insufficient for practical performance.

As another thermal recording method using a laser, US Pat. Nos. 4,602,263 and 4,826,976 disclose compounds whose absorption changes due to thermal decomposition of carbamate. , 5th and 2nd
No. 43,052 describes a compound which develops yellow color by thermal decomposition of a t-butoxycarbonyl group introduced into a hydroxyl group. These methods utilize an irreversible single-molecule reaction, and are preferable for recording images in a very short time using a laser. However, the sensitivity is insufficient and higher sensitivity has been desired. Although the sensitivity can be increased by coexisting an acid catalyst, storage stability is a problem.

[0008] In addition, a UV mask image commonly used for plate making materials (360 nm to 420 nm; corresponds to the exposure light source for PS plates)
No practical proposal has been made in the heat mode method using a laser as a method for forming a semiconductor.

On the other hand, US Pat. No. 5,286,612,
Nos. 5,395,736 and 5,441,850
Nos. 8-503081 and 8-503082 disclose compounds which generate a superacid having a pKa <0 by the action of actinic radiation and a secondary acid generator which generates a secondary acid in the presence of a superacid. ,
And a recording material containing a compound that changes color upon contact with a secondary acid. Although this method is an effective method in terms of increasing the sensitivity of a recording material, the generation of a secondary acid from a secondary acid generator described in the patent is catalyzed only by a super strong acid generated from a super strong acid precursor. Things,
According to the patent publication, the decomposition of about 20 molecules of the secondary acid precursor per 1 molecule of the super-strong acid is catalyzed,
Since the generated secondary acid has no catalytic ability, it cannot be expected to increase the sensitivity by so-called mouse-based acid multiplication.

As compounds capable of multiplying an acid by the action of an acid, K. Ichimura, Chem. Lett. 551 (1995) and JP-A-8-248561 disclose compounds capable of forming an organic acid by decomposition with an acid catalyst. An acid-reactive polymer composition using the compound in combination with a photoacid generator and a substance that undergoes a structural change by the action of an acid is described. However, this document intends a so-called photoresist by the action of an acid generated by a photoacid generator, solubilized or insolubilized in a polar solvent or an alkaline aqueous solution, and intended for a so-called photoresist, and utilized a change in absorption area. There is no description about the recording material.

SUMMARY OF THE INVENTION It is an object of the present invention to provide recording with a low-output laser which has high sensitivity and does not cause ablation even when a heat mode image recording system using a laser is used (particularly for plate making). A novel chemically amplified image recording medium and an image recording method which can perform image recording corresponding to 360 to 420 nm indispensable as a mask film, do not require a separate image receiving sheet, and have excellent storage stability. To provide.

[0011]

The object of the present invention has been attained by the present invention of the following 1) to 10). 1) It contains an acid generator represented by the following general formula 1 which generates an acid by the action of heat or an acid, and a compound which changes the absorption range of 360 to 900 nm by an intramolecular or intermolecular reaction by the action of an acid. An image recording medium characterized by the above-mentioned. Formula 1 AOP In Formula 1, A represents a residue of an acid represented by AOH;
Represents an acid-sensitive substituent capable of being released at a temperature of 150 ° C. or less catalyzed by OH.

2) The image recording medium as described in 1) above, wherein the acid multiplying agent represented by the general formula 1 is at least one compound selected from the following general formulas 2 to 5.

[0013]

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In the formula 2, R ¹ represents an alkyl group or an aryl group, R ² represents an alkyl group, R ³ represents a secondary or tertiary alkyl group having a hydrogen atom at the β-position, and A represents AO
Represents a residue of an acid represented by H.

[0015]

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In the formula 3, R ⁴ , R ⁵ , R ⁶ and R ⁹ each represent a hydrogen atom, an alkyl group or an aryl group;
⁷ and R ⁸ each represent an alkyl group, an aryl group or a silyl group; R ⁷ and R ⁸ may form a ring;
X represents O or S, and A represents an acid residue represented by AOH.

[0017]

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In the formula 4, R ¹⁰ , R ¹¹ and R ¹² each represent a hydrogen atom, an alkyl group or an aryl group, and A represents AO
Represents a residue of an acid represented by H.

[0019]

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In Formula 5, R ¹³ represents an alkyl group or an aryl group, and A represents a residue of an acid represented by AOH.

3) In addition to the acid generator represented by the general formula 1,
The image recording medium according to the above 1) or 2), further comprising a compound that generates an acid by the action of light or heat.

(4) The image recording medium as described in (3) above, wherein the acid generator generating an acid by the action of light or heat is a compound generating a sulfonic acid, a carboxylic acid or a phosphoric acid.

5) The compound which changes the absorption band at 360 to 900 nm by the action of an acid has at least one amino group substituted by a substituent removed by the action of an acid. 5. The image recording medium according to any one of 1) to 4) above, which is a compound that changes the absorption region by a subsequent intramolecular or intermolecular reaction.

(6) The image recording medium as described in (5) above, wherein the substituent of the amino group removed by the action of an acid is an alkoxycarbonyl group.

7) The compound which causes a change in the absorption band of 360 to 900 nm by the action of an acid has at least one hydroxyl group substituted by a substituent removed by the action of an acid, and the compound is removed following the removal of the substituent. The image recording medium according to any one of 1) to 4) above, wherein the compound is a compound that changes the absorption region by an intramolecular or intermolecular reaction.

(8) The image recording medium as described in (7) above, wherein the substituent of the hydroxyl group removed by the action of an acid is an alkoxycarbonyl group, an alkoxymethyl group or a silyl group.

(9) The image recording medium as described in any one of (1) to (8) above, further comprising an infrared absorbing substance.

10) After scanning and exposing the image recording medium according to any of the above 1) to 9) with a laser beam,
An image recording method, wherein the entire surface is heated in a temperature range of 0 to 150 ° C.

[0029]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail. In the acid generator represented by the general formula 1, A represents a residue of an acid represented by AOH (sulfonic acid, carboxylic acid, phosphoric acid, phenol, etc.). AOH is preferably an acid having a pKa <3, and preferred examples include p-toluenesulfonic acid, benzenesulfonic acid, methanesulfonic acid, trifluoromethanesulfonic acid, polyvinylbenzenesulfonic acid, trifluoroacetic acid, and p-nitrobenzoic acid. It is listed as.

P represents an acid-sensitive substituent which is removed by the action of an acid. With the removal of P, an acid represented by AOH is generated from an acid generator represented by AOP. Further, P is an acid (AOH) generated by decomposition of an acid generator (AOP).
Is a substituent that is removed at a temperature of 150 ° C. or less using A as a catalyst, and is preferably a substituent that is removed at a temperature of 120 ° C. or less using AOH as a catalyst. It is used in the present invention. The term "catalyzed" refers to the decomposition temperature of 10 ° C. or higher due to the addition of an acid compared to the case of the compound alone.
It preferably means that the temperature is lowered by 20 ° C. or more.

Examples of such a substituent include an alkyl group having a hydrogen atom at the β-position (eg, t-butyl group, cyclohexyl group, 2-cyclohexenyl group, etc.) and an alkoxycarbonyl group (eg, t-butoxycarbonyl group, cyclohexyl) Oxycarbonyl group, 2- (2-methyl) butoxycarbonyl group, 2- (2-phenyl) propyloxycarbonyl group, 2-chloroethoxycarbonyl group, etc.),
Alkoxymethyl group (for example, methoxymethyl group, ethoxymethyl group, 1-methoxyethyl group, 1-phenoxyethyl group, tetrahydropyranyl group, tetrahydrofuranyl group, 4,5-dihydro-2-methylfuran-5-yl group, etc. ), Silyl groups (for example, trimethylsilyl group, triethylsilyl group, t-butyldimethylsilyl group, phenyldimethylsilyl group, etc.), or these groups, or the decomposition of acetal, ketal, thioketal, pinacol, or epoxy ring is released. And a protecting group (for example, a group substituted with AOH in the description of General Formulas 1 to 4 described later).

When the image recording medium of the present invention is used for heat mode recording such as a laser heat mode, the acid generator represented by the general formula (1) can be acidified by the action of heat (> 150 ° C.) during image recording. It is preferable to have a function of generating an acid. In this case, image formation is possible without adding an acid generator separately.

The acid generator represented by AOP may form a polymer by linking a plurality of polymerizable groups introduced at substitutable positions. In this case, it may be a homopolymer or a copolymer with another monomer.
The molecular weight of the polymer is preferably in the range of 1,000 to 1,000,000, particularly preferably in the range of 2,000 to 300,000. However, in the present invention, the monomer of the acid generator represented by AOP may form a copolymer with a monomer having a function of causing a change in the absorption region of 360 nm to 900 nm by intramolecular or intermolecular reaction by the action of an acid. Absent.

Examples of the acid generator represented by the general formula 1 include, for example, trifluoroacetic acid (α-phenyl-isopropyl) ester, trifluoroacetic acid t-butyl ester,
Toluenesulfonic acid cyclohexyl ester and the like can be mentioned, and in the present invention, the following compounds can be mentioned as particularly preferred examples from the viewpoint of activity and storage stability.

First, compounds represented by the general formula 2 are mentioned. In the general formula 2, R ¹ is an alkyl group (including those having a substituent. The carbon number is preferably 1 to 60. For example, a methyl group, an ethyl group, an iso-propyl group,
t-butyl group, trifluoromethyl group, ethoxymethyl group and the like, or aryl group (including those having a substituent).
The number of carbon atoms is preferably from 6 to 60. For example, it represents a phenyl group, a naphthyl group, a 4-chlorophenyl group, a 2-methoxyphenyl group, a 4-nitrophenyl group, a 3-methanesulfonylphenyl group, etc., and R ² is an alkyl group (a preferred example is R
Represents the same) as those described in ^1, R ³ include those having a secondary or tertiary alkyl group (substituent having a hydrogen atom in the a position beta. Carbon number is preferably 3 to 60. For example t-
Butyl group, cyclohexyl group, tetrahydropyranyl group, tetrahydrofuranyl group, 4,5-dihydro-2-
Represents a methylfuran-5-yl group or a 2-cyclohexenyl group, and A represents an acid represented by AOH (pKa of AOH)
Is preferably 3 or less. For example, p-toluenesulfonic acid, benzenesulfonic acid, methanesulfonic acid, polyvinylbenzenesulfonic acid, p-nitrobenzoic acid, etc.)
Represents a residue.

Specific examples of the compound represented by Formula 2 are shown below, but the present invention is not limited thereto.

[0037]

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[0038]

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[0039]

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The second one is a compound represented by the general formula 3. In formula ^{3, R 4, R 5,} R 6 and R ⁹ are each a hydrogen atom, an alkyl group (preferred examples are the same as described in R ¹⁾ or an aryl group (preferred examples as those described for R ¹ R ⁷ and R ⁸ are an alkyl group (preferred examples are the same as those described for R ¹ ), an aryl group (preferable examples are the same as those described for R ¹ ), or a silyl group (for example, a trimethylsilyl group) , Triethylsilyl group, t-butyldimethyl group, phenyldimethylsilyl group), and R ⁷ and R ⁸ may be bonded to each other to form a ring, and when a ring is formed, —O—C— It is preferable to form a 5- to 10-membered ring together with X-, and particularly preferable to form a 5- or 6-membered ring. X represents O or S, and A represents a residue of an acid represented by AOH (preferred examples are the same as those described in Formula 1).

Hereinafter, specific examples of the compound represented by Formula 3 will be shown, but the present invention is not limited thereto.

[0042]

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[0043]

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The third one is a compound represented by the general formula (4). In the general formula 4, R ¹⁰ , R ¹¹ and R ¹² are each a hydrogen atom, an alkyl group (preferable examples are the same as those described for R ¹ ), or an aryl group (preferable examples are R
Represents the same) as those described in ^1, A represents the residue of an acid represented by AOH (preferred examples are the same as those described in Formula 1).

Hereinafter, specific examples of the compound represented by Formula 4 are shown, but the present invention is not limited thereto.

[0046]

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[0047]

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The fourth is a compound represented by the general formula 5. In the formula, R ¹³ represents an alkyl group (preferred examples are the same as described for R ¹ ) or an aryl group (preferred examples are the same as described for R ¹ ), and A represents AOH
(Preferable examples are the same as those described in the general formula 1).

Hereinafter, specific examples of the compound represented by Formula 5 are shown, but the present invention is not limited thereto.

[0050]

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The above compounds represented by formulas 2 to 5 can be synthesized according to the method described in JP-A-8-248561. It should be noted that any of these acid generators can be partially decomposed by the action of heat due to laser irradiation to generate an acid during image recording in the laser heat mode, so that it is not necessary to add a separate thermal acid generator.

The amount of these acid generators varies depending on the type of the compound having a change in absorption, but is generally preferably in the range of 0.001 to 20 equivalents, particularly preferably, with respect to the compound having a change in absorption. Is the case of 0.01 to 5 equivalents.

When the image recording medium of the present invention is used as a photon mode type image recording medium, it is essential to add a compound which generates an acid by the action of light. On the other hand, when used as a heat mode type image recording medium, if the acid generator represented by the general formula 1 has a function of generating an acid also by the action of heat, a thermal acid generator is separately added. However, a thermal acid generator may be separately added for the purpose of increasing the sensitivity. Further, when the acid generator represented by the general formula 1 does not have a function of generating an acid by the action of heat, it is necessary to separately add a thermal acid generator.

The acid generator which generates an acid by the action of light or heat is a compound which is not an acid in nature, but is a compound which is decomposed by light irradiation or heating to generate an acid. In the present invention, an acid generator that decomposes only at the time of laser exposure and does not decompose at the time of storage or heating over the entire surface after laser exposure is useful.

Compounds that generate an acid by the action of light include “Organic Materials for Imaging”, edited by the Society of Organic Electronics Materials (Bunshin Publishing), pp. 187-198 (1993).
Examples of various ionic compounds such as halides that generate hydrogen halide as nonionic compounds, sulfonates that generate sulfonic acid, carbonyl compounds that generate carboxylic acid, and phosphorus compounds that generate phosphoric acid Salt and the like). Although any of these can be used in the present invention, an acid generator that generates sulfonic acid, carboxylic acid or phosphoric acid is particularly useful from the viewpoint of storage stability of the image recording medium. In addition, various sensitizers (J. Polymer.Sci., 16,
2441 (1978) and the like) can also be added.

Specific examples of the compounds which generate an acid by light useful in the present invention are shown below, but the present invention is not limited to these.

[0057]

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[0058]

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[0059]

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[0060]

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[0061]

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[0062] The mentioned in the first as thermal acid generator which generates an acid by heat is a diazonium, iodonium, sulfonium, sulfonates of aromatic onium compounds such as phosphonium, PF ₆ ^- salt, AsF ₆ ^- salt, SbF ₆ ^- Salt and the like. These are compounds that generate an acid by the action of light, and examples thereof include those described as examples of the photoacid generator.

The second example of the thermal acid generator is an ammonium salt of an acid or an amine complex. Ammonium salts of acids can be synthesized by neutralizing the acid with ammonia or an amine. As the acid for example p- toluenesulfonic acid, benzenesulfonic acid, 1,8-naphthalene disulfonic acid, p- nitrobenzoic acid, 2,4-dichlorobenzoic acid, phenylphosphonic acid, and HPF ₆ and the like. Examples of the amine complex of an acid include a complex obtained by mixing BF ₃ .Et ₂ O and an amine. The amine may be any of primary, secondary or tertiary amines, and it is particularly preferred that the amine is volatile.
Examples include methylamine, ethylamine, iso-propylamine, t-butylamine, aniline, pyridine and the like.

Specific examples of the ammonium salts of these acids are shown below, but the present invention is not limited thereto.

[0065]

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[0066]

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A third example of the thermal acid generator is as follows.
It is a compound that generates β-hydrogen by heating to generate an acid. Such compounds include alkyl esters having a hydrogen atom at the β-position of sulfonic acid, carboxylic acid or phosphoric acid (for example, t-butyl ester, cyclohexyl ester, 2-phenylethyl ester, 4,5-dihydro-
2-methylfuran-5-yl ester, 2-cyclohexenyl ester, etc.), or a compound represented by the following general formula 6.

General Formula 6 YO—NＣＨCH—Z In Formula 6, Y represents a sulfonic acid, carboxylic acid or phosphoric acid residue represented by YOH. Z represents a substituted or unsubstituted aryl group, and preferably has 6 to 60 carbon atoms. Examples thereof include a phenyl group, a 2,4-dimethoxyphenyl group,
Examples thereof include a naphthyl group, a 2-methoxy-1-naphthyl group, and a 2-chloro-1-naphthyl group.

Specific examples of the compound that generates an acid by elimination of β hydrogen by heating are shown below, but the present invention is not limited thereto.

[0070]

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[0071]

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Fourth examples of the thermal acid generator include 2-nitrobenzyl esters of sulfonic acid, carboxylic acid and phosphoric acid, or benzoin esters. These are also compounds that generate an acid by light, and examples thereof include those described above as examples of the photoacid generator.

In the present invention, any of these thermal acid generators can be used, but from the viewpoint of storage stability, an acid generator that generates sulfonic acid, carboxylic acid or phosphoric acid is particularly useful. The decomposition temperature is 130 ° C to 300 ° C.
° C, particularly preferably 150 ° C.
C. to 250.degree.

The sensitivity and storage stability of the recording material can also be controlled by adjusting the amount of these acid generators separately added in addition to AOP of the general formula 1,
Generally, it is preferable to add 1 to 50 mol% to AOP, and particularly preferably, to add 5 to 20 mol%.

In the present invention, a compound that changes the absorption band at 360 to 900 nm by an intramolecular or intermolecular reaction by the action of an acid is stable as long as it is stored under neutral to basic conditions. When an acid acts, the activation energy of the intramolecular or intermolecular reaction is decreased, and the reaction easily proceeds by heating to cause a change in absorption in the above range. At this time, the heating temperature for forming an image is preferably from 60 to 150 ° C, particularly preferably from 80 to 120 ° C. The formation reaction of the color-developed or decolored image and the propagation of the acid can be performed simultaneously.

The compound having such absorption change may be a single compound or may be composed of two or more components. Here, the case of a single compound corresponds to an intramolecular reaction, and the case of two or more components corresponds to an intermolecular reaction.

When a change occurs in the absorption range in the above range, an ON-OFF image in the UV range (360 to 420 nm; corresponding to a PS plate exposure light source) is formed, or a visible image for visual recognition (900 nm or less). Can be formed, and the present invention can be effectively applied to a film for plate making.

As the compound having a change in absorption, for example,
A compound (for example, 9,10-distyrylanthracene and maleic anhydride, tetraphenylcyclopentadiene and an acrylate ester) that forms a decolored image in the region by a Diels-Alder reaction, and a color-developed image in the region by a retro Diels-Alder reaction (For example, an adduct of 9,10-distyrylanthracene and maleic anhydride, an adduct of diphenylisobenzofuran and acrylamide), a conjugated system is expanded by β-hydrogen elimination to form a color image in the region. A compound (for example, 1-acetoxy-1,2-diarylethane, 1-sulfoxy-1,2-diarylethane, etc.), a combination of an aldehyde and an active methylene compound which forms a color image in the area by dehydration condensation (for example, Photograph No. 4) Equivalent magenta coupler and p Methoxycinnamaldehyde) or a compound having in its molecule an amino group or a hydroxyl group substituted by a substituent whose decomposition or elimination is promoted by the action of an acid, and the absorption in the above-mentioned absorption region being changed by the removal of the substituent. And the like. A basic leuco dye or the like which develops color instantly upon contact with an acid can also be used in the image forming medium. However, such a compound acts as a base and uses microcapsules to inhibit the acid growth process. It is necessary to separate from the acid generator of the general formula 1 by coating or applying to another layer.

In the present invention, a compound whose absorption is changed by the decomposition or elimination of a substituent of an amino group or a hydroxyl group by the action of an acid is particularly useful.

Examples of such a substituent of the amino group include an alkoxycarbonyl group (for example, a t-butoxycarbonyl group, a cyclohexyloxycarbonyl group, a 2- (2-methyl) butoxycarbonyl group, a 2- (2-phenyl) propyloxycarbonyl Group, 2-chloroethoxycarbonyl group, etc.), acyl group (eg, acetyl group, benzoyl group, 2-nitrobenzoyl group, 4-chlorobenzoyl group, 1-naphthoyl group, etc.), formyl group or alkoxymethyl group (eg, methoxymethyl group) Groups, ethoxyethyl groups, octyloxymethyl groups, etc.) are preferred examples, but in the present invention, alkoxycarbonyl groups are particularly useful from the viewpoint of storage stability and heat sensitivity. Such compounds include, for example, U.S. Pat. No. 4,602,263.
No. 4,826,976, etc., and it is possible to provide a heat-sensitive recording material having higher sensitivity and excellent preservability by combining with the thermal acid generator and the acid multiplying agent of the present invention. .

The following are specific examples of the compound having an amino group substituted with the substituent, which is useful in the present invention, but the present invention is not limited to these.

[0082]

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[0083]

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[0084]

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[0085]

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[0086]

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[0087]

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As a substituent of a hydroxyl group which is decomposed or eliminated by the action of an acid, an alkoxycarbonyl group (for example, t-
Butoxycarbonyl group, isopropyloxycarbonyl group, 1-phenylethoxycarbonyl group, 1,1-diphenylethoxycarbonyl group, 2-cyclohexeneoxycarbonyl group, 2-chloroethoxycarbonyl group, etc., silyl group (for example, trimethylsilyl group, triethylsilyl) Group, t-butyldimethylsilyl group, t-butyldiphenylsilyl group, phenyldimethylsilyl group, etc.),
Alkoxymethyl group (for example, methoxymethyl group, ethoxymethyl group, 1-methoxyethyl group, 1-phenoxyethyl group, tetranidropyranyl group, tetrahydrofuranyl group, 4,5-dihydro-2-methylfuran-5-yl And a secondary or tertiary alkyl group having a hydrogen atom at the β-position (eg, t-butyl group, cyclohexyl group,
-Cyclohexenyl group) is a preferable example, and in the present invention, an alkoxycarbonyl group is particularly preferable. Examples of compounds whose absorption is changed by decomposition of a hydroxyl group substituent are described in U.S. Pat. No. 5,243,052 or JP-A-9-25360.

The following are specific examples of the compounds useful in the present invention, the absorption of which in the above-mentioned region is changed by decomposition of the substituent of the hydroxyl group, but the present invention is not limited thereto.

[0090]

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[0091]

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[0092]

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[0093]

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[0094]

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[0095]

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[0096]

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[0097]

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[0098]

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[0099]

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The image recording medium of the present invention generally has an acid generator represented by the above general formula 1 and an acid generator of 360 to 9 due to the action of an acid.
It is prepared by applying a composition containing a compound that changes the absorption region of 00 nm and, if necessary, a compound that generates an acid by the action of light or heat on a support. At this time, a binder is usually coexisted, unless one of these is a polymer or an amorphous having good coatability. When the binder does not need to be used, there is an advantage that the film thickness can be easily reduced and a sharp image can be obtained.

For the purpose of enhancing the storage stability of the image recording medium, a small amount of a base may be added, and if necessary, various additives such as a pigment, an antioxidant and an anti-sticking agent may be added. Further, an overcoat layer may be provided to protect the image forming layer, or a backcoat layer may be provided on the back surface of the support. Various known techniques for heat-sensitive recording materials and the like can be used, such as providing a single layer or a plurality of layers of an undercoat layer made of pigment or resin between the image forming layer and the support.

When a base is added, an organic base is preferable. For example, a guanidine derivative (for example, 1,3-diphenylguanidine, 1,3-dimethylguanidine, 1,3-
Dibutylguanidine, 1-benzylguanidine, 1,
1,3,3-tetramethylguanidine, etc.), aniline derivatives (eg, aniline, pt-butylaniline, N,
N′-dimethylaniline, N, N′-dibutylaniline, triphenylamine, etc.), alkylamine derivatives (eg, tributylamine, octylamine, laurylamine, benzylamine, dibenzylamine, etc.), and heterocyclic compounds (eg, N , N'-dimethylaminopyridine, 1,8-diazabicyclo [5.4.0] -7-
Undecene, triphenylimidazole, lutidine, 2
-Picoline and the like) are preferred examples. These bases are preferably added in an amount of 1 to 50 mol%, particularly preferably 5 to 20 mol%, based on the acid generator.

Examples of the binder include water-soluble binders such as gelatin, casein, starches, hydroxyethyl cellulose, carboxymethyl cellulose, polyvinyl alcohol, polyacrylamide, and ethylene-maleic anhydride copolymer, and polyvinyl butyral, triacetyl cellulose, polystyrene, and acrylic acid. Any water-insoluble binder such as a methyl-butadiene copolymer and an acrylonitrile-butadiene copolymer can be used.

When a pigment is added, examples include diatomaceous earth, talc, kaolin, calcined kaolin, titanium oxide, silicon oxide, magnesium carbonate, calcium carbonate, aluminum hydroxide, and urea-formalin resin.

Other additives include ultraviolet absorbers such as benzophenone type and benzotriazole type, head wear and sticking preventives comprising higher fatty acid metal salts such as zinc stearate and calcium stearate, paraffin, paraffin oxide, polyethylene, Examples include waxes such as polyethylene oxide and caster wax, which can be added as needed.

As the support used in the image recording medium of the present invention, papers such as high quality paper, baryta paper, coated paper, cast coated paper, synthetic paper, polyethylene, polypropylene, polyethylene terephthalate, polyethylene-2, polyethylene-2
6-naphthylene dicarboxylate, polyarylene,
Examples thereof include polymer films such as polyimide, polycarbonate, and triacetyl cellulose, glass, metal foil, and nonwoven fabric. In the case where the image recording medium of the present invention is used for a transmission type image such as an OHP film or a plate making film, a transparent support is used. For a plate making film, a support having a small coefficient of thermal expansion and good dimensional stability and having no absorption in the photosensitive region of the PS plate is selected.

When the acid generator contained in the image recording medium of the present invention is a compound which generates an acid by the action of heat, image recording is performed in a heat mode. At this time, a heating method as an image forming means includes a method of contacting with a heated block or plate, a method of contacting with a heat roller or a heat drum, a method of irradiating a halogen lamp or an infrared or far-infrared lamp heater, There are a method of imagewise heating with a thermal head of a printer, a method of irradiating a laser beam, and the like. However, a method of irradiating a laser beam is preferred when a high resolution is required such as for a plate making material. Further, in order to form an image with less heat energy, the heat-sensitive recording material of the present invention can be heated to an appropriate temperature in advance.

When an image is formed by irradiating a laser beam, a dye that absorbs light of the wavelength of the laser beam must be present in order to convert the laser beam into heat energy. Excimer laser, argon laser, helium neon laser, semiconductor laser, glass (YAG) laser, carbon dioxide laser,
Although there is a dye laser and the like, a helium neon laser, a semiconductor laser and a glass laser are laser light sources useful in the present invention. Among them, a semiconductor laser is particularly useful because the device is small and inexpensive. The oscillation wavelength of a semiconductor laser is usually 670 to 830 nm, and a dye having absorption in the near infrared is used.

As near infrared absorbing dyes, cyanine dyes,
Squarylium dyes, merocyanine dyes, oxonol dyes, phthalocyanine dyes and the like are used. Specific examples thereof include, for example, U.S. Pat. Nos. 4,973,572, 4,948,777, and 4,950,639.
No. 4,948,776 and No. 4,948,778
Nos. 4,942,141 and 4,952,55
No. 2, 5,036,040 and 4,91
The substances described in the specification of 2,083 are exemplified.

In the present invention, an image catalyst can be generated from the thermal acid generator by the above-described heating method in an image-wise manner and then heated over the entire surface to amplify the image. In this case, it is essential that the temperature for heating the entire surface is a temperature at which the decomposition of the acid generator in the non-image area does not occur. must not. The heat development temperature in the present invention is preferably in the range of 60 ° C to 150 ° C, particularly preferably 80 to 120 ° C.

When the acid generator contained in the image recording medium of the present invention is a compound that generates an acid by the action of light, the acid generator or the sensitizer added to widen the photosensitive area may be used. The laser light source is selected according to the absorption wavelength. The thermal development after laser exposure is the same as the case where a thermal acid generator is used.

[0112]

The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the present invention is limited thereto.

<Production Example of Thermosensitive Recording Sheet> The following compounds were dissolved in chloroform, coated on a 100 μm-thick polyethylene terephthalate film, and dried to produce a transparent thermosensitive recording sheet. As the polystyrene, polystyrene beads (diameter: about 3.2 mm) manufactured by Wako Pure Chemical Industries, Ltd. were used.

Sample-1 B- (1) 4 mmol / m ² D- (1) 2 mmol / m ² IR dye 40 mg / m ² Polystyrene 0.85 g / m ²

Sample-2 B- (1) 4 mmol / m ² D- (25) 2 mmol / m ² IR dye 40 mg / m ² Polystyrene 0.85 g / m ²

Sample-3 B- (1) 4 mmol / m ² D- (49) 2 mmol / m ² IR dye 40 mg / m ² Polystyrene 0.85 g / m ²

Sample-4 B- (8) 4 mmol / m ² D- (1) 2 mmol / m ² IR dye 40 mg / m ²

Sample-5 B- (21) 4 mmol / m ² D- (1) 2 mmol / m ² IR dye 40 mg / m ² Polystyrene 0.85 g / m ²

Sample-6 B- (36) 4 mmol / m ² D- (1) 2 mmol / m ² IR dye 40 mg / m ² Polystyrene 0.85 g / m ²

Sample-7 B- (51) 4 mmol / m ² D- (1) 2 mmol / m ² IR dye 40 mg / m ²

Sample-8 B- (1) 4 mmol / m ² D- (1) 2 mmol / m ² AG- (35) 0.4 mmol / m ² IR dye 40 mg / m ² Polystyrene 0.85 g / m ²

Sample-9 B- (1) 4 mmol / m ² D- (1) 2 mmol / m ² AG- (31) 0.4 mmol / m ² IR dye 40 mg / m ² Polystyrene 0.85 g / m ²

Sample-10 B- (1) 4 mmol / m ² D- (53) 2 mmol / m ² IR dye 40 mg / m ² Polystyrene 0.85 g / m ²

Sample-11 B- (1) 4 mmol / m ² C- (30) 2 mmol / m ² IR dye 40 mg / m ² Polystyrene 0.85 g / m ²

Reference Sample-1 Paratoluenesulfonic acid 4 mmol / m ² D- (1) 2 mmol / m ² IR dye 40 mg / m ² Polystyrene 0.85 g / m ²

Reference Sample-2 D- (1) 2 mmol / m ² IR dye 40 mg / m ² Polystyrene 0.85 g / m ²

Reference Sample-3 D- (25) 2 mmol / m ² IR dye 40 mg / m ² Polystyrene 0.85 g / m ²

Reference Sample-4 D- (49) 2 mmol / m ² IR dye 40 mg / m ² Polystyrene 0.85 g / m ²

Reference Sample-5 Reference Compound-1 4 mmol / m ² D- (1) 2 mmol / m ² AG- (35) 0.4 mmol / m ² IR dye 40 mg / m ² Polystyrene 0.85 g / m ²

Reference sample-6 Reference compound-1 4 mmol / m ² D- (1) 2 mmol / m ² AG- (31) 0.4 mmol / m ² IR dye 40 mg / m ² Polystyrene 0.85 g / m ²

Reference Sample-7 Nitrocellulose (viscosity 1000 seconds, manufactured by Daicel Industries, Ltd.) 0.85 g / m ² Reference Dye-1 0.35 g / m ² Reference Dye-2 0.55 g / m ² IR Dye-1 40mg / m ²

Reference Sample-8 Polyvinyl butyral 0.85 g / m ² Reference Dye-1 0.35 g / m ² Reference Dye-2 0.55 g / m ² IR Dye-1 40 mg / m ²

[0133]

Embedded image

Example 1 <Laser Exposure Conditions for Image Recording> Spectra Diode
Labs No. SDL-2430 (wavelength range: 800-830nm)
This multiplexing was performed to obtain an output of 400 mW to obtain an image writing laser. Using this laser, beam system 16
0 μm, laser scanning speed of 0.83 m / sec (center of scanning), sample feed speed of 15 mm / sec, and scanning pitch of 8 lines / mm, and the above-mentioned exposure so as to form an image of 22 mm × 9 mm was described above. Performed on samples. At this time, the laser energy density on the sample was 3 mJ / mm ² .

After scanning exposure was performed on Samples 1 to 9 and Reference Samples 1 to 4 under the above laser exposure conditions, the color density at 360 nm in the exposed portion was examined. Next, these laser-exposed samples were heat-developed under heating conditions of 120 ° C. and 30 seconds, and then the color densities of exposed and unexposed portions were determined.

The obtained results are shown in Table 1 (the color density is a value corrected by subtracting the absorption density of the raw film).

[0137]

[Table 1]

From Table 1, it can be seen that Reference Samples-2 to 4 containing no acid did not develop any color by laser exposure and thermal development after exposure, whereas Samples 1 to 9 of the present invention exhibited thermal development after laser exposure. It can be seen that this shows good color development.
Further, in the sample of the present invention, the color density of the exposed portion is increased by thermal development after laser exposure, but no color is formed in the unexposed portion, so that a high-contrast image can be obtained. In samples-1 to 7, B- (1), B- (8), B- (21), B- (21)
Since (36) and B- (51) have a function of generating an acid by the action of heat, a color image can be obtained without adding an acid generator separately as in Samples 8 and 9.

Example 2 The above Samples-1 to 9 and Reference Sample-1 were stored at 60 ° C. for 3 days, and the color density at 360 nm was examined. Further, the color development density of each of these samples after heat development at 120 ° C. for 30 seconds was examined. Further, the color density when the sample after storage was subjected to laser exposure under the above exposure conditions and the color density when heat developed (120 ° C., 30 seconds) after laser exposure were examined. Table 2 shows the obtained results.

[0140]

[Table 2]

Table 2 shows that Reference Sample-1 developed color under the above storage conditions, whereas Samples-1 to 8 of the present invention did not show any color development even after storage, and did not develop any color when only heat development was performed. No high storage stability was found. In addition, it can be seen that Samples 1 to 8 of the present invention have good color developability by laser exposure after storage and thermal development after exposure, which is not different from the results shown in Table 1. In addition, it can be seen that Samples 1 to 8 of the present invention using a sulfonic acid precursor as a thermal acid generator have better storage stability than Sample 9 of the present invention using a superacid precursor.

Example 3 <Laser Exposure Conditions for Image Recording> In the laser exposure method described in Example 1, by changing the laser scanning speed and the laser output, the exposure in which the energy density was changed as shown in Table 3 was performed. The test was performed on the above-mentioned Samples-1 to 11 and Reference Samples-5 to 8.

<Comparison of image forming efficiency> Sample-1 of the present invention
After the laser scanning exposure, heat development of 120 ° C. and 30 seconds was performed on each of Sample Nos. 11 to 11 and Reference Samples 5 and 6 to determine the maximum color density at the laser scanning center (image portion).
The image forming efficiency (coloring efficiency) was calculated from the comparison with the theoretical value when the color was developed at 00%. For Reference Samples-7 and 8, the image formation efficiency (erasing efficiency) was calculated from the comparison of the density between the laser scanning center (image portion) and the non-image portion. Table 3 shows the obtained results.

[0144]

[Table 3]

Samples Nos. 1 to 11 of the present invention were prepared as described in JP-A-8-50.
It can be seen that the sensitivity is higher than that of Reference Samples -5 and 6 in which the secondary acid generator (Reference Compound-1) described in No. 3081 was added together with the thermal acid generator. Particularly, in Reference Sample-5 in which Reference Compound-1 and an acid generator that generates sulfonic acid are combined, almost no color development is observed. The sample of the present invention is 3 mJ
It can be seen that an image can be efficiently formed even with a low energy of / mm ² or less, and has higher sensitivity than Samples 7 and 8 using ablation by a laser beam.

[0146]

According to the present invention, high-sensitivity, low-power laser recording that does not cause ablation even when a heat mode image recording method using a laser is used (especially as a mask film for plate making) 360
It is possible to obtain a novel image recording medium and an image recording method which can perform image recording corresponding to 420 nm, do not require a separate image receiving sheet, and have excellent storage stability.

Claims (10)

[Claims] 1. An acid generator represented by the following general formula 1 which generates an acid by the action of heat or an acid, and a compound which changes the absorption range of 360 to 900 nm by an intramolecular or intermolecular reaction by the action of an acid. An image recording medium comprising: Formula 1 AOP In Formula 1, A represents a residue of an acid represented by AOH;
Represents an acid-sensitive substituent capable of being released at a temperature of 150 ° C. or less catalyzed by OH. 2. The image recording medium according to claim 1, wherein the acid proliferating agent represented by the general formula 1 is at least one compound selected from the following general formulas 2 to 5. Embedded image In the formula 2, R ¹ represents an alkyl group or an aryl group, R ²
Represents an alkyl group, and R ³ represents 2 having a hydrogen atom at the β-position.
A represents a tertiary or tertiary alkyl group, and A represents a residue of an acid represented by AOH. Embedded image In Formula 3, R ⁴ , R ⁵ , R ⁶ and R ⁹ each represent a hydrogen atom, an alkyl group or an aryl group, and R ⁷ and R ⁸
Represents an alkyl group, an aryl group or a silyl group, R ⁷ and R ⁸ may form a ring, X represents O or S, and A represents an acid residue represented by AOH. Embedded image In Formula 4, R ¹⁰ , R ¹¹ and R ¹² each represent a hydrogen atom, an alkyl group or an aryl group, and A represents a residue of an acid represented by AOH. Embedded image In Formula 5, R ¹³ represents an alkyl group or an aryl group, and A represents a residue of an acid represented by AOH. 3. The image recording medium according to claim 1, further comprising a compound capable of generating an acid by the action of light or heat, in addition to the acid generator represented by the general formula 1. 4. The image recording medium according to claim 3, wherein the acid generator that generates an acid by the action of light or heat is a compound that generates sulfonic acid, carboxylic acid or phosphoric acid. 5. A compound which causes a change in the absorption band at 360 to 900 nm by the action of an acid, has at least one amino group substituted by a substituent removed by the action of an acid. The image recording medium according to any one of claims 1 to 4, wherein the compound is a compound that changes the absorption region by a subsequent intramolecular or intermolecular reaction. 6. The image recording medium according to claim 5, wherein the substituent of the amino group removed by the action of an acid is an alkoxycarbonyl group. 7. A compound which causes a change in the absorption band at 360 to 900 nm by the action of an acid, has at least one hydroxyl group substituted by a substituent removed by the action of an acid, and is subsequently removed. The image recording medium according to any one of claims 1 to 4, wherein the compound is a compound that changes the absorption region by an intramolecular or intermolecular reaction. 8. The image recording medium according to claim 7, wherein the substituent of the hydroxyl group removed by the action of an acid is an alkoxycarbonyl group, an alkoxymethyl group or a silyl group. 9. The image recording medium according to claim 1, further comprising an infrared absorbing substance. 10. After scanning and exposing the image recording medium according to any one of claims 1 to 9 with a laser beam, 60-
An image recording method, wherein the entire surface is heated in a temperature range of 150 ° C.