JPH0222645A - Heat developable copying material - Google Patents

Abstract

PURPOSE:To obtain high color development density even by low temperature development by forming a coating layer composed essentially of carboxyl- modified polyvinyl alcohol and an epoxy-modified polyamide resin on a photosensitive layer. CONSTITUTION:The coating layer composed essentially of carboxyl-modified polyvinyl alcohol and an epoxy-modified polyamide resin is formed on the photosensitive layer. At least one of a diazo compound and a coupling component is contained in microcapsules, and the shells of them are made of polyurea or polyurethane, and it is preferred to use said polyvinyl alcohol and said polyamide in a weight ratio of 10:(0.5-10), especially, 3-8, thus permitting high color development density to be obtained even by low temperature development.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a copying material, particularly a heat-developable copying material that utilizes the photosensitivity of a diazo compound (diazonium salt). More specifically, the present invention relates to a heat-developable copying material that has excellent water resistance and improved film surface strength.

<Prior Art> There are three types of copying materials that utilize the photosensitivity of diazo compounds.

The first type is known as a wet development type, in which a photosensitive layer containing a diazo compound and a coupling component as main components is provided on a support, this material is superimposed on the original, and after exposure, it is developed in an alkaline solution. It is something to do. The second type is known as a dry development type, which, unlike the wet type, develops with ammonia gas. The third type is known as a heat-developable type, and includes a type that contains an ammonia gas generating agent such as urea that can generate ammonia gas by heating in the photosensitive layer, and a type that contains trichloroacetic acid in the photosensitive layer. There are types that contain alkaline salts of acids that lose their acid properties when heated, and types that utilize higher fatty acid amides as coloring aids to activate diazo compounds and coupling components by heating and melting. .

In addition to maintenance problems such as the need for replenishing and discarding the developer as it uses a developer and the large size of the device, the wet type also has problems with maintenance, such as the fact that it is wet immediately after copying, making it difficult to make additions immediately. There are several problems such as copy images not being able to withstand long-term storage. In addition, like the wet type, the dry type requires replenishment of developer, requires gas absorption equipment to prevent the generated 7mm gas from leaking outside, and therefore requires larger equipment. To,
There are problems such as the smell of ammonia immediately after copying. On the other hand, unlike the wet and dry types, the heat-developable type has the advantage of maintenance because it does not require a developer, but all conventional types require high-temperature development at 150°C to 200°C. Moreover, if the temperature is not controlled to about ±10<9 >C, insufficient development or changes in color tone occur, resulting in an increase in the cost of the apparatus. Furthermore, the diazo compound used for such high-temperature development is required to have high heat resistance, but such compounds are often disadvantageous for high-temperature formation. Low temperature development (90°C to 130°C
) have been attempted, but they have the drawback of decreasing the shelf life of the material itself.

As described above, although the thermal development type is expected to have sufficient advantages in terms of maintenance compared to the wet and dry types, the current situation is that it has not yet become the mainstream of diazo copying systems.

Now, in order to obtain the desired color density by heating a material in which a layer containing a diazo compound, a coupling component, and a coloring aid is provided on a support, each component instantly melts, diffuses, and reacts by heating. It is necessary to generate a coloring pigment by If we design a material that can sufficiently develop color and obtain a high concentration even at low heating temperatures, there is always the possibility that this reaction will occur even while it is stored at room temperature before copying, resulting in white color. This appears as a phenomenon in which the bare skin becomes colored.

In order to solve this incompatible problem, the inventors of the present invention made extensive studies and found that a copying material is provided with a heat-developable photosensitive layer containing a diazo compound, a coupling component, and a coloring aid on a support. It was discovered that one basic solution is to contain at least one of the diazo compound or the coupling component in microcapsules. However, these microcapsules are easily destroyed by physical strain applied to the coating film, such as pressure, as is conventionally used in pressure-sensitive paper. There was still a need for ways to suppress the destruction of the capsules due to the dry shrinkage force of the coating film, which can occur during the process of coating and drying to obtain a product.

The destruction of microcapsules appears as a phenomenon of discoloration of the skin. Therefore, it would be impossible to achieve the improvements in water resistance and film surface strength necessary for use as copying materials, particularly drawings, unless a means for suppressing the destruction of the capsules was discovered.

Therefore, a first object of the present invention is to provide a copying material that can obtain high color density even by low-temperature development.

A second object of the present invention is to provide a copying material that has a good shelf life, that is, a low density of background coloring (fog) during storage before copying.

A third object of the present invention is to provide a copying material with excellent water resistance, chemical resistance, and abrasion resistance.

A fourth object of the present invention is to provide a simple and easy-to-maintain image forming method that uses the copying material described above and combines a latent image formation process by exposure and a development process by heating.

Means for Solving Problems> The above aspects of the present invention provide a copying material in which a heat-developable photosensitive layer containing a diazo compound, a coupling component, and a coloring aid is provided on a support. This was achieved by a heat-developable copying material characterized in that an I layer containing carboxy-modified polyvinyl alcohol and epoxy polyamide resin as main components is provided on the photosensitive layer. At this time, at least one of the diazo compound and the coupling component is contained in the microcapsule, and the wall of the microcapsule is formed of at least one kind of polymer selected from polyurea and polyurethane. It is preferable that there be.

The carboxy-modified polyvinyl alcohol used in the coating layer of the present invention is obtained by saponifying a copolymer of vinyl acetate and an ethylenic dicarboxylic acid such as maleic acid, fumaric acid, or itaconic acid, which is described in JP-A-53-91995. Preferably, those obtained by The amount of carboxy modification is 1 to 10 mol%, the degree of saponification is 60 to 90%, and the degree of polymerization is 500 to 25.
00 is more preferable.

The epoxidized polyamide resin that reacts with the carboxy-modified polyvinyl alcohol and becomes insoluble in water is separately called polyamide polyamine epichlorohydrin resin, and is generally produced as follows. Diamines containing secondary 7-mino groups in the molecule (e.g. diethylenetriamine, etc.) and dicarboxylic acids (e.g. adipic acid, etc.)
Poly7midobolyamine is produced by a dehydration condensation reaction with poly(7mide), then epichlorohydrin is added to this as a crosslinking agent during the curing reaction, and after the reaction is completed, the pH is adjusted with hydrochloric acid.
When made acidic, a cationic polyamide polyamine epichlorohydrin resin is produced.

The ratio of carboxy-modified polyvinyl alcohol and epoxidized polyamide resin used is preferably 0.5 to 10 parts by weight, more preferably 3 to 8 parts by weight, per 10 parts by weight of carboxy-modified polyvinyl alcohol.

The coating layer of the present invention may optionally contain kaolin, calcined kaolin, talc, calcium carbonate, amorphous silica, barium sulfate, aluminum hydroxide, urea-formalin resin powder,
Inorganic and organic pigments such as polyethylene resin powder, polystyrene fine powder, waxes such as polyethylene wax, carnauba wax, paraffin wax, microcrystalline wax, fatty acid 7-amide, zinc stearate,
Metal soaps such as calcium stearate and surfactants may also be added.

The coating amount of the I layer of the present invention is 061 to 59/m in terms of solid content.
2, preferably 0.5 to 39/m2. The amount of application is
When the amount is less than this, the effect is small, and when it is more than this, it is necessary to raise the developing temperature, which is not preferable.

The diazo compound and the coupling component contained in the photosensitive layer of the present invention develop color when they come into contact with each other when heated, and the diazo compound decomposes when exposed to light of a specific wavelength before the coloring reaction. Photodegradable compounds are used.

The photodegradable diazo compound as used in the present invention mainly refers to aromatic diazo compounds, and more specifically refers to aromatic diazonium salts, diazosulfonate compounds, and diazoamino compounds. It is generally said that the photodecomposition wavelength of a diazo compound is its maximum absorption wavelength. Also, the maximum absorption wavelength of diazo compounds ranges from around 200 nm to 70 nm, depending on their chemical structure.
It is known that it changes to about 0 nm. (“Photodecomposition and chemical structure of photosensitive diazonium salts” by Takahiro Tsunoda and Ao Yamaoka, Journal of the Photographic Society of Japan 29 (4) pp. 197-205 (
+965)) That is, when a diazo compound is used as a photodegradable compound, it is decomposed by light of a specific wavelength depending on its chemical structure. Furthermore, by changing the chemical structure of the diazo compound, the hue of the dye after the reaction can be changed even when the same coupling component is used for the coupling reaction.

A diazo compound is a compound represented by the general formula ArN2X. (In the formula, Ar represents a substituted or unsubstituted aromatic ring,
N2 represents a diazonium group, and x represents an acid anion. ) In the present invention, a multicolor heat-developable copying material can be obtained by using diazo compounds having different photodecomposition wavelengths or different photodecomposition rates.

Specific examples of the diazo compound used in the present invention include the following examples.

4-diazo-1-dimethylaminobenzene, 4-diazo-2-butoxy-5-chloro-1-dimethyl-7minobenzene, 4-diazo-1-methylbenzyl-7minobenzene, 4-diazo-1-ethylhydroxyethylaminebenzene, 4-Diazo-1-diethylamino-3-methoxy
Sibenzene, 4-diazo-1-morpholinobenzene, 4
-Diazo-1-morpholino-2,5-dibutoxybenzene.

4-Diazo-1-tolylmercapto-2,5-jethoxybenzene, 4-diazo-1-piperazino-2-methoxy-5-chlorobenzene, 4-diazo-1-(N,N
-dioctylaminocarbonyl)henzene, 4-diazo-1-(4-tart-octylphenoxy)benzene, 4-diazo-1-(2-ethylhexanoylpiperidino)-2゜5-dibutoxybenzene, 4- Diazo-1-
(2゜5-di-tert-amylphenoxy-α-butameylpiperidino)benzene, 4-siacy 1-(4-
methoxy)phenylthio-2,5-jethoxybenzene, 4-diazo-1-(4-methoxy)benzamide-2
, 5-jethoxybenzene, 4-diazo-1-pyrrolidino-2-methoxybenzene Specific examples of acids that form diazonium salts with the above-mentioned diazo compounds include the following examples.

C, F2. , ++C0OH (n is an integer from 1 to 9), c,
.

F2--1sO3H (m is an integer of 1 to 9), tetraboron fluoride, tetraphenylboron, hexafluorophosphoric acid, aromatic carboxylic acid, aromatic sulfonic acid.

Metal halides (zinc chloride, cadmium chloride, tin chloride)
etc.) The coupling components used in the present invention are those that form dyes by force-sampling with diazo compounds in a basic atmosphere, and include so-called active methylene compounds having a methylene group next to a carbonyl group, phenol derivatives, and naphthol derivatives. Specific examples include the following.

Resorcin, phloroglucin, sodium 2,3-dihydroxynaphthalene-6-sulfonate, 1-hydroxy-2-naphthoic acid morpholinopropylamide, 1,5-
Dihydroxynaphthalene, 2,3-dihydroxynaphthalene, 2,3-dihydroxy-6-sulfanylnaphthalene, 2-hydroxy-3-naphthoic acid morpholinopropylamide, 2-hydroxy-3-naphthoic acid octylamide, 2-hydroxy-3- Naphthoic acid 7nilide, pencylacetonilide, 1-phenyl-3-methyl-5
-pyrazolone, 1-(2,4,6-drichlorophenyl)-3-7nilino-5-pyrazolone, 2-[3-α-
(2,5-di-tert-amylphenoxy)-butanamidobenzmido]phenol, 2,4-bis-(benzoylaceto7mino)toluene, 1,3-bis-(pivaloylacetaminomethyl)benzene These coupling components can be used alone or in combination of two or more, and any hue can be obtained as required.

As one of the color development aids of the present invention, it is preferable to add a basic substance as necessary for the purpose of making the system basic during thermal development and promoting the coupling reaction.

As these basic substances, used are sparingly water-soluble or water-insoluble basic substances, and substances that generate alkali upon heating.

Basic substances include inorganic and organic ammonium salts,
organic amines, amides, urea and thiourea and their derivatives,
Nitrogen-containing compounds such as thiazoles, virols, pyrimidines, piperazines, guanidines, indoles, imidazoles, imidacillines, triazoles, morpholines, piperidines, 7midines, formamidines, and pyridines are listed. It will be done. Two or more of these basic substances can be used in combination.

In addition, the color development aid of the present invention includes phenol derivatives, naphthol derivatives, alkoxy-substituted benzenes, and flukoxy-substituted naphthalenes in the photosensitive layer so that heat development can be carried out quickly and completely with low energy. , hydroxy compounds, amide compounds, and sulfonamide compounds can be added. These compounds are thought to lower the melting point of the coupling component or the basic substance, or to improve the thermal permeability of the microcapsule wall, resulting in a high color density.

The coloring aids of the present invention also include thermofusible substances.

The heat-melting substance is a substance having a melting point of 50°C to 150°C that is solid at room temperature and melts by heating, and is a substance that dissolves a diazo compound, a coupling component, or a basic substance. Specific examples of these compounds include fatty acid amides, N-substituted fatty acid amides, ketone compounds, urea compounds, esters, and the like.

Microcapsules containing the diazo compound and coupling component of the present invention are disclosed in, for example, JP-A-59-190886.
It can be prepared by the method described in No. Furthermore, the purpose of the present invention is to create microcapsules that are substantially free of solvent by dissolving a diazo compound or a coupling component together with a capsule wall-forming monomer in a low-boiling non-aqueous solvent, and distilling off the solvent while carrying out a polymerization reaction. It is preferable to use The polyurea and polyurethane that form the walls of the microcapsules can be obtained by polymerizing the corresponding monomers by the method described above. , 01 to 0.3.

Further, it is preferable to apply the diazo compound at 0.05 to 5.09/m2.

In the present invention, the coupling component is 0.1 to 30 parts by weight and the basic substance is 0.1 to 30 parts by weight per 1 part by weight of the diazo compound.
．． It is preferable to use it in a proportion of 1 to 30 parts by weight.

The diazo compound, coupling component, basic substance, and other color development aids that are not contained in the microcapsules used in the present invention are preferably used after being solidly dispersed together with a water-soluble polymer using a sand mill or the like. Preferred water-soluble polymers include water-soluble polymers used when preparing microcapsules (for example, JP-A-59-190
(See No. 886). In this case, the diazo compound, coupling component, and coloring aid are each added in an amount of 5 to 40% by weight based on the water-soluble polymer solution.

Preferably, the dispersed particle size is 10 microns or less.

A free radical generator (a compound that generates free radicals when irradiated with light) used in photopolymerizable compositions can be added to the copying material of the present invention for the purpose of reducing yellowing of the background after copying. . As free radical generators, aromatic ketones,
Examples include quinones, benzoin, benzoin ethers, azo compounds, organic disulfides, and acyloxime esters. The amount of the free radical generator to be added is preferably 0.01 to 5 parts by weight per 1 part by weight of the diazo compound.

Similarly, for the purpose of reducing yellowing, a polymerizable compound having an ethylenically unsaturated bond (hereinafter referred to as a vinyl monomer) can be used.

Vinyl monomers have at least one ethylenically unsaturated bond (vinyl group, vinylidene group, etc.) in their chemical structure.
It is a compound that has the chemical form of a monomer or a prepolymer. Examples thereof include unsaturated carboxylic acids and salts thereof, esters of unsaturated carboxylic acids and aliphatic polyhydric alcohols, amides of unsaturated carboxylic acids and aliphatic polyhydric amine compounds, and the like. The vinyl monomer is used in an amount of 0.2 to 20 parts by weight per 1 part by weight of the diazo compound.

It is particularly preferable that the free radical generator and the vinyl monomer are contained in microcapsules together with the diazo compound.

In the present invention, in addition to the above materials, citric acid is used as an acid stabilizer.
Tartaric acid, oxalic acid, boric acid, phosphoric acid, pyrophosphoric acid, etc. can be added.

The copying material of the present invention can be prepared by preparing a coating solution containing a diazo compound, a coupling component, a basic substance, and other additives, and coating it on a support such as paper or a synthetic resin film by bar coating, blade coating, or coating. 7. A photosensitive layer having a circular area of 2.5 to 309/m<2> is provided by coating and drying by a coating method such as knife coating, gravure coating, roll coating, spray coating, or dip coating. The copying material of the present invention may have a laminated structure in which the diazo compound, coupling component, base, etc. may be contained in the same layer as described in the above method, or may be contained in separate layers. You can also do it. It is also possible to provide an intermediate layer on the support as described in Japanese Patent Application No. 177,669/1980, and then coat the photosensitive layer.

As the support of the present invention, any filter paper support used for ordinary pressure-sensitive paper, thermal paper, dry or wet diazo copying paper, etc. can be used, as well as neutral sizing agents such as alkyl ketene dimer. Neutral paper with a pH of 6 to 9 (described in Japanese Patent Application No. 55-14281) sized by paper with an optical surface roughness of 8μ or less and a thickness of 30 to 150μ as described in JP-A-58-136492, a density of 0.99 parts as described in JP-A-58-69091 cm
Paper with an optical contact ratio of 3 or less and an optical contact ratio of 15% or more, JP-A-5
Canadian Standard Freeness (JIS) as described in No. 8-69097
P8121) paper made from pulp beaten to 4000C or higher to prevent coating liquid from seeping in, JP-A-58
-65695, the glossy side of base paper made by a Yankee machine is used as the coating surface to improve the color density and resolution, and the base paper described in JP-A-59-35985 is subjected to corona discharge treatment to improve coating suitability. Improved paper can also be used.

Further, the synthetic resin film used as the support in the present invention can be arbitrarily selected from known materials that are dimensionally stable and less deformed by heating during the development process. Examples of such films include polyester films such as polyethylene terephthalate, polybutylene terephthalate, and polycarbonate, cellulose derivative films such as cellulose triacetate films, polystyrene films, polypropylene films, polyolefin films such as polyethylene, and polyimide films. It can be used as a plant or as a paste. The thickness of the support used is 20 to 200 microns.

The following method is preferred for forming an image on the copying material of the present invention. In the process of forming a latent image on the photosensitive layer by exposing it to light corresponding to the image of the original, and fixing areas other than the image forming area by light irradiation, various fluorescent lamps, xenon lamps, mercury lamps, etc. are used as the light source for exposure. It is preferable that the emission spectrum substantially matches the absorption spectrum of the diazo compound used in the copying material, since areas other than the image forming area can be efficiently optically fixed. Further, in the step of heating and developing the entire photosensitive layer of the material, a thermal pen, a thermal head, an infrared ray, a high frequency, a heat block, a heat roller, etc. can be used as the heating means.

<Effects of the Invention> As detailed above, the copying material of the present invention has excellent water resistance and membrane properties while maintaining a good shelf life due to the coating layer containing carboxy-modified polyvinyl alcohol and epoxy poly7amide resin as main components. We were able to improve the surface strength.

EXAMPLES Hereinafter, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to these Examples.

<Example> 3.45 parts of 1-morpholino-2,5-dibutoxybenzene-4-diazonium hexafluorophosphate, xylylene diisocyanate and trimethylolpropane (3.45 parts)
: 1) 18 parts of the adduct were added to a mixed solvent of 6 parts of tricresyl phosphate and 5 parts of ethyl acetate, and dissolved by heating. This diazo compound solution was mixed with an aqueous solution containing 5.2 parts of polyvinyl alcohol dissolved in 58 parts of water, and emulsified and dispersed at 20oC to obtain an emulsion having an average particle size of 2.5μ. 100 parts of water was added to the obtained emulsion and heated to 60°C while stirring, and after 2 hours, a capsule liquid containing the diazo compound in the core substance was obtained.

Next, 10 parts of 2-hydroxy-3-naphthoic acid 7nylide and 10 parts of triphenylguanidine were added to 200 parts of a 5% polyvinyl alcohol aqueous solution and dispersed in a sand mill for about 24 hours to obtain a dispersion with an average particle size of 3 μm.

To 50 parts of the capsule solution of the diazo compound obtained as described above, 50 parts of a dispersion of a coupling component and triphenylguanidine and 10 parts of a 40% calcium carbonate dispersion were added to prepare a coating liquid. Spread this coating solution on smooth high-quality paper (7
5q/m2) using a coating bar to dry weight 10
Copying material A was prepared by applying the coating at a coating density of 9/m2 and drying at 50°C for 1 minute.

On the other hand, as a coating liquid for the protective layer, 5% polyvinyl alcohol 1
00 parts and 5 parts of a 40% calcium carbonate dispersion was prepared, and a dry weight of 2 c was added on copying material A.
+/rn2 using a coating bar, and dried at 50° C. for 1 minute to prepare copying material 8.

The following two types of liquids were prepared as the coating liquid for the coating layer of the present invention,
Coating and drying were carried out in the same manner as Copying Material B to prepare Copying Materials C%D.

Coating layer coating liquid for copying material C: 100 parts of 3% carboxy-modified polyvinyl alcohol aqueous solution (PVA KL-318 manufactured by Kuraray@), 5 parts of 40% calcium carbonate dispersion,
Seven parts of a 30% epoxidized polyamide resin aqueous solution (FL-71 manufactured by Toho Chemical Co., Ltd.) were mixed.

Coating layer coating solution for copying material: 100 parts of 3% carboxy-modified polyvinyl alcohol aqueous solution (PVA KL-118 manufactured by Kuraray ■), 20 parts of 20% kaolin dispersion, 30%
1.5 parts of zinc stearate dispersion, 2.5 parts of 20% stearamide dispersion, 20% aqueous epoxidized polyamide resin solution (Polyfix 203 manufactured by Showa Kobunshi @)
10 parts were mixed.

Test manuscript on copy materials A-D (a circle with a diameter of 3 cm painted uniformly black on tracing paper with a 2B pencil)
was placed on top and exposed to fluorescent light. At this time, a fluorescent lamp whose emission spectrum has a maximum value at 420 parts m was used. Next, an image was formed by heating for 3 seconds using a beat block heated to 120°C. In the same way,
Heat block temperatures of 100°C and 1160°C were also tested. In addition, in order to test the shelf life, the sample was stored at 40° C. and 90% RH for 24 hours, exposed to light in the same manner, and developed at 120° C. 2 at 60'030%RH
A 4-hour storage test was also conducted. The densities of the colored parts and background parts of the samples obtained in each test were measured using a Macbeth densitometer.

After measuring the concentration of samples A-D obtained by the above test,
Drop 5 cc of water onto the sample surface, and use your finger to
The coating was rubbed 0 times and the degree of peeling of the coating layer was examined. (The results are shown in Table 3.) Table 1 shows the results of tests with different heating temperatures, and Table 2 shows the results of the pre-copy storage test.

As shown in Tables 1 to 3, the copying material provided with the coating layer of the present invention maintains a good shelf life, obtains high color density even by low-temperature heat development, and has improved water resistance on the film surface. was recognized as doing so.

The * mark in the table was tested as a comparative example for the present invention. This indicates that the sample was

~that's all~

Claims (1)

[Scope of Claims] 1) A copying material in which a heat-developable photosensitive layer containing a diazo compound, a coupling component, and a coloring aid is provided on a support, wherein carboxy-modified polyvinyl alcohol and epoxy 1. A heat-developable copying material characterized by being provided with a coating layer containing a polyamide resin as a main component. 2) At least one of the diazo compound and the coupling component is contained in the microcapsule,
2. The heat-developable copying material according to claim 1, wherein the walls of the microcapsules are made of at least one polymer selected from polyurea and polyurethane. 3) A step of exposing the copying material according to claim 1 to light corresponding to the image of the original to form a latent image on the photosensitive layer, and fixing the area other than the image forming area by light irradiation, and the exposure step. An image forming method comprising the step of subsequently heating and developing the entire surface of the photosensitive layer of the copying material.