JPH09193540A - Photosensitive thermal recording material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a photosensitive thermal recording material protecting a color forming element from the direct contact with the outside and made excellent in pencil writing properties and touch without damaging fixing properties or color forming properties by using a binder having no spectral absorption max. within a specific light wavelength region in a protective layer. SOLUTION: In a photosensitive thermal recording material wherein a recording layer performing recording and fixing using heat and light and a protective layer are provided on a support in this order, a binder in the protective layer has no spectral absorption max. within a light wavelength region of 300-400nm. By this constitution, it is estimated that the absorption of light by the protective layer can be suppressed to a range exerting no effect on the color forming capacity or fixing capacity of the recording layer. As the binder satisfying this condition, a cellulose derivative such as methyl cellulose, carboxymethyl cellulose, hydroxymethyl cellulose, nitrocellulose, cellulose acetate propionate or cellulose acetate is designated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the durability of a recording layer of a light and heat sensitive recording material which develops color by heating and then irradiating light without degrading the coloring property or photofixability of the recording layer. The present invention relates to a light and heat sensitive recording material having improved printability.

[0002]

2. Description of the Related Art A direct thermal recording material using a thermal head has a simple recording device structure, high reliability and no maintenance required, and recording is performed only by contact heating, resulting in low noise during recording. Only consumables are paper. Therefore, it has excellent features such as low running cost and is widely used in various fields such as facsimiles and printers.

As these direct thermal recording materials, Japanese Patent Publication No.
Generally, those utilizing the color reaction of a colorless or light-colored electron-donating dye precursor and an electron-accepting compound disclosed in JP-A No. 5-14039 and JP-B No. 43-4160 are used. It has the drawbacks that the contents can be modified by further heating and recording after printing and that the white background gradually develops color. This is because the color developability of the uncolored portion of the heat-sensitive recording material once recorded is stopped after recording, that is, so-called fixing is not performed, and a heat-sensitive recording material capable of fixing is required.

As a result of intensive studies on a thermosensitive coloring system having a fixing property, we have developed a photochromic element comprising a compound which decomposes by light and an element which develops a color by reacting with a decomposition product thereof.
It was discovered that a light and heat sensitive recording material in which a latent image is formed by being mixed by heat and the latent image is colored by light has a fixing property.

The light used for decomposing a compound which is decomposed by light in such a light and heat sensitive recording material can be used as any light, but it is not easy to handle the light and heat sensitive recording material before color development in a bright room. Light in the visible region and light in the ultraviolet region are often used because of the ease of assembling the photochromic element. Further, among the light in the ultraviolet region, the light source is easily available and the light source is inexpensive, and more specifically, ultraviolet light in the long wavelength region, more specifically 300 nm to 400 n.
The m area is often used.

On the other hand, in the case of a heat-sensitive recording material, the head is prevented from being worn or corroded due to contact with the head, protection of the coloring element from direct contact with the outside, ink or pencil when newly writing on the recording paper. It is known to provide a protective layer on the recording layer in order to improve the so-called writing property for improving the glue and the touch feeling. The role that the protective layer plays in the heat-sensitive recording material is also the function required in the light- and heat-sensitive recording material, and we examined providing a protective layer on the side opposite to the support on the recording layer side.

However, in the case of a light and heat sensitive recording material, providing a protective layer similar to that of the heat sensitive recording material has a problem that the performance is greatly lowered. Specifically, there is a problem that the fixing property is lowered when fixing is carried out by light irradiation, and the color density is lowered when light irradiation is involved in the color forming reaction. The cause is unknown, but it is presumed that the following mechanism causes a problem.

Compounds which are decomposed by light used in the light and heat sensitive recording materials rarely absorb light of a wide wavelength with strong intensity. Many of the elements that are decomposed by light strongly absorb light of a certain specific wavelength, but weakly absorb light of other wavelengths. The rate of decomposition of compounds that are decomposed by light with light of a weakly absorbed wavelength does not increase. In addition, it is rare for the light source of the light that is irradiated to decompose the element that decomposes by light to obtain strong light emission in a wide wavelength range, and many light sources emit extremely strong light emission called a bright line spectrum at a specific wavelength. It can be seen that the emission intensity is relatively small at wavelengths other than the bright line spectrum. Moreover, it is difficult to match with high accuracy the wavelength of light whose light-decomposing element exhibits strong light absorption and the wavelength of light emitted by the light source with high accuracy. In many cases, these two wavelengths are used in a shifted state. It will be. When the protective layer is provided on the recording layer, the protective layer itself absorbs light and the amount of light reaching the recording layer is reduced accordingly. As a result, it is presumed that problems such as deterioration in fixing property and decrease in color density occurred.

[0009]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and to prevent the action of light of a light and heat sensitive recording material, specifically, the fixability and color developability, from the outside of the color forming element. Another object of the present invention is to provide a light and heat sensitive recording material which is excellent in protection from direct contact with, pencil writing and touch.

[0010]

The above object of the present invention is attained by the following constitutions.

1. In a light and heat sensitive recording material containing a recording layer for recording and fixing using heat and light on a support and a protective layer on the recording layer, the binder in the protective layer spectrally absorbs at a light wavelength of 300 to 400 nm. A light and heat sensitive recording material characterized by having no maximum.

2. 2. The light and heat sensitive recording material as described in 1 above, wherein the binder in the protective layer is a polyvinyl alcohol derivative.

3. 2. The light and heat sensitive recording material as described in 1 above, wherein the binder in the protective layer is a polypeptide derivative.

That is, we have conducted extensive studies on the problems to be solved by the present invention, and have examined the elements forming the protective layer of the heat-sensitive recording material.

As a result, in the case of a light and heat sensitive recording material, we have found that the performance of the light and heat sensitive recording material greatly changes due to the spectral absorption characteristics of the binder used in forming the protection layer among the elements forming the protection layer. Discovered, at a position far from the support with respect to the recording layer, a light wavelength of 300 to 400n
It has been discovered that the problem to be solved by the present invention is achieved by a light and heat sensitive recording material characterized in that a protective layer formed by using a binder having no spectral absorption maximum in m is provided.

Light wavelength of 300 to 400n as a binder
The reason why the problem was achieved by using only a binder having no spectral absorption maximum in m is unknown, but the following causes are presumed.

The elements forming the protective layer of the heat-sensitive recording material include pigments, antistatic agents, matting agents and binders for adhering these to the recording material. Among the above-mentioned elements, the binder is the one that is coated over the entire surface of the recording layer at a position distant from the support. From this fact, the binder itself generally emits light in the wavelength range used for fixing and exposing color, more specifically 300 to 400 nm.
In the case where the compound exhibits a spectral absorption maximum in the wavelength region of, the binder itself absorbs the light absorbed by the compound that decomposes due to light, so that the effect on the photocoloring element becomes the largest. It is presumed that this was the largest cause of the performance deterioration of the light and heat sensitive recording material due to the formation of the protective layer.

Therefore, the binder is used as light in the wavelength region generally used for fixing and color development by exposure, more specifically, 300.
By forming a protective layer with a binder that does not have a spectral absorption maximum in the wavelength region of up to 400 nm, the absorption of light by the protective layer affects its coloring performance and fixing performance without changing other elements of the protective layer. It is presumed that it became possible to hold it in a range that does not exist.

Hereinafter, the present invention will be described in detail.

The photodecomposable compound used in the light and heat sensitive recording material is a compound which is decomposed by light such as ultraviolet light, visible light or infrared light, for example, a so-called photo free radical generator or a diazonium compound. , Azide compounds and the like. Examples of the photo free radical generator include JP-A-62-39.
No. 728, 2,4,6-described in JP-A No. 63-2099.
Triarylimidazole dimer compound, US Pat.
282,693, azide compounds such as 2-azidobenzoxadiazole, benzoyl azide and 2-azidobenzimidazole, U.S. Pat. No. 3,615,568.
3'-Ethyl-1-methoxy-2-pyridothiacyanine perchlorate, pyridinium compounds such as 1-methoxy-2-methylpyridinium-p-toluenesulfonate, N-bromosuccinimide, tribromomethylphenyl sulfone, Diphenyl iodine, 2-trichloromethyl-5- (p-butoxystyryl) -1,3,4
-Oxadiazole, 2,6-bis (trichloromethyl) -4- (p-methoxyphenyl) -s-triazine and other organic halogen compounds, benzophenone, thioxanthone, anthraquinone, benzoin ether and other carbonyl compounds, azobisisobutyrate Examples thereof include azo compounds such as ronitrile, alkyl disulfides, organic sulfur compounds such as mercaptan, and phosphorus compounds such as triphenylphosphine.

After being decomposed by light, the compound decomposed by light is colored by the reaction with the decomposition product and an element which is colored to generate a dye. At this time, the decomposition product may form a part of the dye to be formed, or may be involved in the dye forming reaction and may be changed to a compound different from the dye. It depends on the combination of a compound that decomposes by light and an element that reacts with the decomposition product to develop a color, and is selected in consideration of the generation efficiency, color tone, fastness, extinction coefficient and the like of the dye formed by the reaction.

Although various reactions can be used as the photo-coloring element, the following three types can be mainly mentioned.

[0023] In the above reaction formula, A represents a photodegradable compound and A'represents a photolysis product. In addition, B, C, and D represent elements that develop color by reacting with A '. Further, D ', B-C, and A-C represent the produced coloring dyes. Further, B'is the one changed by the reaction of B with A '. The above reaction formulas are schematic representations of each type of reaction, and are useful for understanding what the dye skeleton formed is derived from. In the above reaction formula, the element that reacts with A'and develops color is
The case where it consists of a single compound (types 1 and 3) and the case where it consists of two kinds of compounds (type 2) are described.
It may consist of three or more types. Further, although an auxiliary component (for example, a base or an acid) that accelerates the dye-forming reaction is not described, it may be contained in the photo-coloring element.

That is, in the case of type 1, D reacts with the photodecomposition product of A and D to form a coloring dye by oxidation, decomposition, etc., and the basic skeleton of the coloring dye is derived from D. . For example, a compound that decomposes by light is
Examples include a photo free radical generator such as a 2,4,6-triarylimidazole dimer or an organic halogen compound, and an element which reacts with a decomposition product thereof is a leuco dye.

In this case, the decomposition products by light irradiation are imidazolyl free radicals and halogen free radicals, which have strong oxidizing power. Due to this oxidizing power, for example, the leuco dye can be oxidized to become a coloring element.

Examples of leuco dyes include US Pat.
The products described in No. 45,234 can be used, for example, the following products. Aminotriarylmethane, aminoxanthene, aminothioxanthene, amino-9,10
-Dihydroacridine, aminophenoxazine, aminophenothiazine, aminodihydrophenazine, aminodiphenylmethane, leucoindamine, aminohydrocinnamic acid (cyanoethane, leucomethine), hydrazine, leucoindigoid dye, aminodihydroanthraquinone,
4,4'-biphenol, 2- (p-hydroxyphenyl) -4,5-diphenylimidazole, phenethylaniline.

Further, as a photo-free storage agent used in combination with the above leuco dye, 2,4,6-triarylimidazole dimer compound, tribromomethylphenyl sulfone, 2,6-bis (trichloromethyl) ) -4
Examples thereof include organic halogen compounds such as-(p-methoxyphenyl) -s-triazine. In addition, these photo free radical generators can be sensitized with intrinsic sensitivity and spectral sensitivity by using together various sensitizers.

In the case of type 2, A'reacts with C (for example, a coupling reaction) to form a coloring dye. In this case, the basic skeleton of the coloring dye produced is derived from B and C. As an example, the compound that decomposes by light is a photo-radical generator having an oxidizing power similar to that of the type 1, and the elements that react with the decomposition product to develop a color are a coupler and an aromatic primary amine. Such cases can be mentioned.
For example, it is known that an aromatic primary amine such as N, N-diethyl-p-phenylenediamine or 4-aminoantipyrine is oxidatively coupled with a phenol or an active methylene compound to form an azomethine dye. As is well known in the field of light-sensitive materials, the above-mentioned free radicals can be used to cause an oxidative coupling reaction to produce a dye. As aromatic primary amines that can be used, p-aminophenol, N, N-diethyl-2-methyl-p-phenylenediamine, N-ethyl-N-methanesulfonylaminoethyl-2-, other than the above-mentioned amines, can be used. Methyl-p-phenylenediamine, N, N-
Examples thereof include didodecyl-p-phenylenediamine.

Further, the above-mentioned aromatic primary amine is used in the form of hydrochloride, sulfate, tosylate, perfluoroalkyl sulfonate, etc., if necessary. In addition, acyl compounds such as acetyl compounds, benzoyl compounds, p-toluenesulfonyl compounds, (2,4-di-t-pentyl-phenoxy) acetyl compounds, and p-dodecyloxyphenylsulfonyl compounds are also used.

As the coupler for forming a dye by oxidative coupling with an aromatic primary amine, those known in the field of silver halide color photographic light-sensitive materials are used. Specific examples of the coupler include phenol. , Naphthols,
Examples thereof include pyrazolones, pyrazolotriazoles, acylacetanilides and the like. Further, both a so-called 2-equivalent coupler in which a leaving group is substituted at the active site of the coupler and a 4-equivalent coupler in which the active site is not substituted are used. If necessary, a base may be used in combination to accelerate the reaction.

In the case of type 3, A'reacts with C (for example, a coupling reaction) to form a coloring dye.
The basic skeleton of the color-developing dye that is produced unlike the type 1 is derived from A and C. An example is the case where the compound that decomposes by light is an aromatic azide, and the element that reacts with the decomposition product to form a dye is a coupler. When an aromatic azide compound is decomposed by light, nitrene is produced. The nitrene thus formed can form an azomethine dye by reaction with the above-mentioned coupler. Examples of azide compounds that can be used include 4-
(N, N-diethylamino) phenyl azide, 2,5-
Dibutoxy-4-morpholinophenyl azide, 2,5-
Dibutoxy-4-phenylthiophenyl azide, 4-
(N-ethyl-N-methylsulfonylaminoethylamino) -2-methylphenyl azide, 4-diethylamino-3-dodecyloxycarbonylphenyl azide, 1-
There are naphthyl azide, 2-naphthyl azide, anthranil azide, 3-quinoline azide, 9-acridine azide and the like. Moreover, as the coupler which forms a dye by coupling with an azide, the same ones as mentioned above can be mentioned.

In the present invention, there is no particular limitation on the amount of the compound that decomposes by light and the element that develops a color by reacting with its decomposition product, but the film thickness, the coloring efficiency and the coloring density when applied to the support. It is selected in consideration of the above. The preferable amount of use in each case is 4 × 10 ^{−4 to} 6 × 10 ⁻³ mol /
It is in the range of m ² . Further, the film thickness when applied on the support is not particularly limited, but in consideration of heat sensitivity and image sharpness, the dry film thickness is 0.5 μm to 50 μm.
Is preferable, and a range of 1 μm to 20 μm is more preferable.

In the light and heat sensitive recording material of the present invention, it is desirable to add an element for deactivating the photodecomposition product in order to improve the fixability and prevent so-called white background stain in which the non-recorded portion is colored. The element that deactivates a photodegradation product is specifically an element that causes a reaction that deactivates the oxidation activity or coupling activity of a photodegradation product, and specifically, a reducing agent, a proton donor, or a photocatalyst. Examples thereof include compounds that bind to decomposition products and change into colorless compounds, stable free radicals, and the like. More specifically, the following examples can be given.

1) Compounds such as hydroquinone, catechol, resorcinol, hydroxyhydroquinone, pyrologricinol and aminophenol in which a benzene ring has a hydroxyl group and another position of the benzene ring is substituted with a hydroxyl group or an amino group 2) 1-phenylpyra Zolidine-3-one, 1-phenyl-4-methylpyrazolidin-3-one, 1-phenyl-4,4-dimethylpyrazolidin-3-one, 3-methyl-1- (p-sulfophenyl ) -2-Pyrazoline-5
-One, 3-methyl-1-phenyl-2-pyrazolin-
Cyclic phenylhydrazide compounds such as 5-one 3) Guanidine compounds such as 1,3-diphenylguanidine, phenylguanidine, 1,3-di-o-tolylguanidine, 1-o-tolylbiguanide, 1-benzylidene-guanidideamino, Alkylenediamine compounds such as diethylenediamine, propylenediamine, tetramethylenediamine, hexamethylenediamine and octamethylenediamine 4) Hydroxyamine compounds such as diethanolamine and triethanolamine, dodecylamine, di-n-hexylamine, isopropylamine, t- Butylamine,
Aliphatic or aromatic primary amines such as p-phenylenediamine and 2,2,6,6-tetramethylpiperidine 5) Primary and secondary amines such as n-octanol, benzyl alcohol and 3-octanol Alcohol and 2,6-di-t
-Phenol derivatives such as butylphenol. Heterocyclic compounds with hydroxyl groups such as citrazinic acid 6) Trialkylmethane compounds such as 2,3-dimethylpentane and 3-methylundecane 7) Coupling of 4-position with photodegradation products such as alkyl groups and phenyl groups 5-substituted by a substituent that does not leave
Pyrazolone derivatives and 5-isoxazolone derivatives 8) α-isopropyl-β-methylethylene, styrene, cinnamic acid, 3-hexen-1-ol, cyclohexene, chain-like cyclic olefin compounds such as trimethylolpropane triacrylate 9) α , Α-diphenyl-β-picrylhydrazyl, p
-Stable free radicals such as p'-difluorodiphenylamino and carbinoxyl.

The element for deactivating these photodegradation products can be used properly according to the coloring mechanism and the photocoloring element used. The element for deactivating the photodegradation product may be used alone or in combination of two or more kinds. Among the elements for deactivating these photodegradation products, the above elements 1), 2) preferably acting as a reducing agent, 3), 4), 5) as a proton donor, and 7) Examples thereof include a pyrazolone derivative, an isoxazolone derivative, and an element which forms a colorless compound by coupling with a decomposition product such as an olefin compound of 8). More preferably, when the photodecomposable element is a photo free radical generator and the photodecomposition product generated therefrom acts as an oxidizing agent, it is a reducing agent or a proton donor, and the photodecomposable element is a diazo compound or azide. In the case of a compound having a strong coupling activity such as a carbene produced from a diazo compound or a nitrene produced from an azide compound, a photolysis product is a pyrazolone of 7), an isoxazolone derivative or an olefin compound of 8). be able to.

Elements that deactivate these photodegradation products are added to the recording layer. The amount used is required to be sufficient to inactivate the photodecomposition product generated in the non-heated recording portion, but if the amount used is too large, the color density decreases. The amount of the element that inactivates the photodegradation product may be experimentally determined, but it is preferable to use 0.1 to 100 equivalents, and more preferably 0.5 to 100 equivalents of the compound that is decomposed by light. It is 10 equivalents.

In the present invention, all the components of the compound that decomposes by light, the element that reacts with the decomposition product to develop a color, and the element that deactivates the photodecomposition product are uniformly mixed before heating. There is no such thing. At least one component of the element that develops color by reacting with the compound that decomposes by light and its decomposition product must be isolated by some means before heating. The isolation method requires isolation that does not cause a color reaction even if a compound which is decomposed by light during storage is partially decomposed.

As a segregation method that can be used, for example, each component can be dispersed by emulsification or solid dispersion to avoid uniform mixing. Further, for more reliable isolation, the components to be isolated at the time of storage are divided into separate layers on the support and applied. It is also effective to provide an intermediate layer between each layer. A more preferred form of isolation is to use microcapsules.

The microcapsules preferred in the present invention prevent contact between substances inside and outside the capsule at room temperature due to the substance sequestering action of the walls of the microcapsules, and increase the permeability of the substance when heated at a certain temperature. The permeability of the microcapsules depending on the temperature can be controlled by changing the glass transition temperature of the capsule wall depending on the capsule wall material, core substance, additives, and the like.

The microcapsule wall material usable in the present invention includes polyurethane, polyurea, polyether, polycarbonate, urea-formaldehyde resin,
Examples thereof include melamine-formaldehyde resin, polystyrene, styrene-methacrylate copolymer, polyester, gelatin, polyvinylpyrrolidone and polyvinyl alcohol. A plurality of these wall materials may be used in combination.

Of the above wall materials in the present invention, polyurethane, polyurea, polyamide, polyester, polycarbonate, polyester and the like are preferable, and polyurea and polyurethane are particularly preferable.

For details of the microcapsules which can be preferably used in the present invention, see US Pat. No. 3,79.
No. 6,696.

The microcapsules used in the present invention are prepared by emulsion polymerization in which a core substance containing a substance to be encapsulated is emulsified, and then a wall of a polymer substance is formed around the oil droplets for microcapsulation. The method is preferred. At that time, it is preferable to use an organic solvent to form emulsified oil droplets as necessary, and the organic solvent to be used can generally be appropriately selected from high-boiling organic solvents.

For example, phosphoric acid ester, phthalic acid ester, acrylic acid ester, methacrylic acid ester and other carboxylic acid ester, aliphatic amide, alkylated biphenyl, alkylated terphenyl, chlorinated paraffin,
Alkylated naphthalene, diarylethane and the like are used.

Specifically, JP-A-60-242094,
The compounds described in JP-A-62-75409 can be used. In addition to the above high boiling point organic solvent, a low boiling point organic solvent such as ethyl acetate or methylene chloride can be used as a dissolution aid. On the other hand, in the water layer mixed with the oil layer,
A water-soluble polymer can be contained as a protective colloid, and for example, polyvinyl alcohol, gelatin, or cellulose derivative can be used. Further, when emulsifying and dispersing, a suitable one can be selected from known surfactants so as to prevent precipitation or aggregation.

Other color-forming elements and additives to be present outside the microcapsules may be dispersed by either solid dispersion or emulsion dispersion, but emulsion dispersion is preferable.

In the present invention, there is no particular limitation on the amount of the compound which decomposes by light and the element which develops a color by reacting with the decomposition product thereof, but the film thickness, the coloring efficiency and the coloring density at the time of coating on the support. It is selected in consideration of the above. The preferable amount of use in each case is 4 × 10 ^{−4 to} 6 × 10 ⁻³ mol /
It is in the range of m ² . Also, the film thickness when applied on the support is not particularly limited, but in consideration of heat sensitivity and image sharpness, the dry film thickness is 0.5 μm.
The range of m to 50 μm is preferable, and the range of 1 μm to 20 μm is more preferable.

In the light and heat sensitive recording layer of the light and heat sensitive recording material of the present invention, a compound which is decomposed by light and an element which reacts with the decomposition product to develop a color and an element which inactivates the decomposition product are coated on a support, It can be made by forming an impregnated or self-supporting layer.

At this time, as the binder of the above dispersion, various emulsions such as polyvinyl alcohol, gelatin, styrene-butadiene latex, carboxymethyl cellulose, gum arabic, polyvinylpyrrolidone, polyvinyl acetate, polyacrylic acid ester and the like can be used. , The amount used is 0.5 to 5 g / m in terms of solid content
²

In the light and heat sensitive recording material of the present invention, the wear and corrosion of the head due to contact with the head is prevented, the color forming element is protected from direct contact with the outside, ink and ink are newly written on the recording paper. A protective layer is provided on the recording layer in order to improve the so-called writing property, which improves the paste of the pencil, and the touch feeling. The binder used for forming the protective layer is a wavelength of light used for decomposing the photodecomposable compound contained in the photochromic element in order to prevent deterioration of the decomposability of the compound decomposable by light. 300-40
It must have no spectral absorption maximum in the light wavelength region of 0 nm.

Specific examples of the binder that does not have a spectral absorption maximum in the light wavelength region of 300 to 400 nm satisfying the above conditions include the following.

1) Cellulose derivatives such as methylcellulose, carboxymethylcellulose, hydroxymethylcellulose, nitrocellulose, cellulose acetate propionate and cellulose acetate 2) Starch, gum arabic, polysaccharides such as sodium alginate 3) Polyacrylamide derivatives, polyvinylpyrrolidone , Sodium polystyrene sulfonate, etc. 300-4
Polyethylene derivative not substituted with a substituent having a spectral absorption maximum in the light wavelength region of 00 nm, 300 to 400 n
Examples of the substituent having a spectral absorption maximum in the light wavelength region of m include quinolino group, N, N-dialkylanilino group, o-
Amino-p-carboxyphenyl group etc. are mentioned 4) Styrene-maleic acid copolymer etc. ethylene derivative-maleic acid derivative copolymer 5) Polyvinyl alcohol, carboxy modified polyvinyl alcohol, polyvinyl acetate emulsion polyvinyl alcohol etc. Derivatives 6) Resins such as silicone resins, epoxy resins, phenol resins, fluororesins, melamine resins 7) Polypeptide derivatives such as gelatin and casein.

Other than the above, known materials used as a binder for the protective layer of the heat-sensitive recording material are 300 to 400.
Any substance having no spectral absorption maximum in the light wavelength region of nm can be used as the binder of the protective layer of the light and heat sensitive recording material of the present invention.

Among these binders that can be used as the protective layer, the polyvinyl alcohol derivative of 5) and the polypeptide derivative of 7) are preferable.

As the filler for the protective layer, those known as the filler for the protective layer of the heat-sensitive recording material can be used. Specifically, inorganic pigments, organic pigments, metal soaps, etc. can be used. As inorganic pigments, zinc oxide, calcium carbonate, barium sulfate,
Inorganic pigments such as titanium oxide, lithobon, talc, sekiseki, kaolin, aluminum hydroxide, amorphous silica and colloidal silica are preferable. It is also possible to use organic pigments and metal soaps. Waxes can also be added. These fillers may be used alone or in combination of two or more.

In order to form the protective layer uniformly, a known surfactant can be added to the protective layer coating solution. As a method for dispersing the filler in the binder, known methods can be widely used.

The protective layer of the light and heat sensitive recording material of the present invention is applied to the recording layer at a position distant from the support. The coating amount of the protective layer is not particularly limited as long as the protective properties and the properties of the light and heat sensitive recording material as a recording material are not impaired, but the solid content coating amount is 0.5 g / m ² to 20 g. / M ² It is preferable to apply within the range,
It is more preferable to carry out the coating within the range of 0.5 g / m ² to 10 g / m ² .

When the light and heat sensitive recording layer and the protective layer of the light and heat sensitive recording material of the present invention are coated on a support such as paper and synthetic resin film, generally well known coating methods can be used. . For example, it may be applied by a dip coating method, an air knife coating method, a curtain coating method, a roller coating method, a doctor coating method, a wire bar coating method, a slide coating method, a gravure coating method, a spin coating method or an extrusion coating method. it can.

As the support that can be used in the light and heat sensitive recording material of the present invention, paper, regenerated cellulose, cellulose acetate, cellulose nitrate, polyethylene terephthalate, polyethylene, polyvinyl acetate, polyethylene naphthalate, etc. film, glass , Wood, metal, etc.

The light source which can be used in the present invention may be any light source as long as it can decompose a compound which is decomposed by light, such as a fluorescent lamp, a high pressure mercury lamp, a halogen lamp, a xenon lamp, a tungsten lamp or sunlight. However, it is preferable that the protective layer emits ultraviolet rays in a long wavelength region well because of the light transmittance of the protective layer.

[0061]

EXAMPLES Examples are shown below, but the present invention is not limited to these examples. Further, "part" indicating the addition amount indicates "part by weight".

Example 1 (Preparation of capsule liquid A) Leuco dye: benzoyl leuco methylene blue 1.0 part Wall material: Xylidene isocyanate / trimethylolpropane adduct 15 parts Additive: Dodecylbenzenesulfonic acid 0.4 part Dissolution aid Agent: Methylene chloride 5 parts Dissolution aid: 1-Phenyl-1-xysilylethane 5 parts were uniformly dissolved. This solution was added to 54 parts of a 6% polyvinyl alcohol aqueous solution and emulsified and dispersed at 20 ° C. using a homogenizer to obtain an emulsion having an average particle size of 1 μm. 60 parts of water was added to the obtained emulsion and stirring was continued at 40 ° C. for 3 hours. Then, it returned to room temperature and obtained the capsule liquid A.

(Preparation of Dispersion Liquid of Free Radical Generator) Photo free radical generator: 30 parts of tribromomethylphenyl sulfone Element for deactivating photodegradation product: 1 part of 1-phenylpyrazolidin-3-one 60 parts % Polyvinyl alcohol aqueous solution and dispersed by a sand mill to obtain a photo free radical generator dispersion liquid having an average particle diameter of 1 μm.

(Preparation of coating liquid for light and heat sensitive recording layer) 12 parts of the above-mentioned capsule liquid A and 4 parts of the above dispersion liquid of photo free radical generator were mixed to prepare a coating liquid for the light and heat sensitive recording layer.

(Preparation of Coating Solution for Protective Layer) Pigment: Kaolin 3 parts Binder: 4% aqueous polyvinyl alcohol solution (absorption maximum 260 nm) 20 parts The above components are dispersed in a sand mill to give a coating solution for protective layer having an average particle size of 0.5 μm. Prepared.

(Preparation of Light and Heat Sensitive Recording Material) The above light and heat sensitive recording layer coating solution was coated on a high quality paper with a wire bar so that the coating amount of the leuco dye was 0.5 g / m ² and dried at 50 ° C. A thermosensitive recording layer was formed.

Next, the protective layer coating solution was coated on the light and heat sensitive recording layer so that the solid content was 2 g / m ² , and the temperature was 50 ° C.
And dried to obtain a light and heat sensitive recording material of the present invention.

Example 2 (Preparation of Capsule Solution B) Coupler: 1.5 parts of 2,4-dichloro-3-ethyl-6- [2- (2,4-ditertiary pentylphenyloxy) butanoylamino] phenol Additive: dodecylbenzenesulfonic acid 0.4 part Wall material: xylidene diisocyanineate / trimethylolpropane adduct 15 parts Dissolution aid: ethyl acetate 5 parts High boiling solvent: isopropyl biphenyl 5 parts were uniformly dissolved. This solution was added to 54 parts of an aqueous solution of 6% polyvinyl alcohol, and emulsified and dispersed at 20 ° C. using a homogenizer to obtain an emulsion having an average particle size of 1 μm.
60 parts of water was added to the obtained emulsion and stirring was continued at 40 ° C. for 3 hours. Then, it returned to room temperature and obtained the capsule liquid B.

(Preparation of Photo-Free Radical Generator / Amine Dispersion) 2,2-Bis (o-chlorophenyl) -4,4 ′, 5,5′-tetraphenylimidazole 10 parts N, N-dioctylamino-p -Phenylenediamine perfluorobutanesulfone salt 10 parts Triphenylguanidine 5 parts 1,4-hydroquinone 10 parts Methylene chloride 30 parts Tricresyl phosphate 30 parts Add to 200 parts of 4% polyvinyl alcohol aqueous solution and ultrasonically disperse A photo free radical generator / amine dispersion was obtained.

(Preparation of coating liquid for light and heat sensitive recording layer) 10 parts of the above-mentioned capsule liquid B 23 parts of the above-mentioned photo free radical generator / amine dispersion liquid A coating liquid for light and heat sensitive recording layer was prepared by mixing the above components.

(Preparation of Coating Solution for Protective Layer) Pigment: Colloidal silica 3 parts Binder: 4% aqueous solution of polyvinyl alcohol (absorption maximum 260 nm) 20 parts Disperse the above with a sand mill and coat the protective layer with an average particle size of 0.5 μm. Was prepared.

(Preparation of Light and Heat Sensitive Recording Material) The above light and heat sensitive recording layer coating solution was applied on a high quality paper with a wire bar so that the amount of the coupler applied was 0.5 g / m ² , and dried at 50 ° C. A recording layer was formed.

Next, the protective layer coating solution was coated on the light and heat sensitive recording layer so that the solid content was 2 g / m ² , and the temperature was 50 ° C.
And dried to obtain a light and heat sensitive recording material of the present invention.

Example 3 (Preparation of Capsule Solution C) Azide: 4-morpholino-2,5-dibutoxyphenyl azide 3 parts Fixing accelerator: phenidone 3 parts High boiling solvent: diisopropylnaphthalene 10 parts Wall material: xidene diiso Cineanate / trimethylolpropane adduct 8 parts Dissolution aid: Ethyl acetate 5 parts were uniformly dissolved. This solution was added to 46 parts of an 8% aqueous solution of phthalated gelatin, and 18 parts of water was used to emulsify and disperse 2 parts of a 10% aqueous solution of sodium dodecylbenzenesulfonate at 40 ° C using a homogenizer. Two
After 0 part was added to homogenize the mixture, stirring was continued at 40 ° C. for 3 hours. Then, it returned to room temperature and obtained the capsule liquid C.

(Preparation of Coupler Dispersion) 7-chloro-6-tert-butyl-3- (3-dodecylsulfonylpropyl) pyrazolo [3,2-c] triazole 4 parts triphenylguanidine 2 parts tricresyl phosphate 1 32 parts of gelatin (15% aqueous solution), 5 parts of dodecylbenzenesulfonic acid (10% aqueous solution), and 3 parts of water.
0 part was added, and the resulting emulsion was emulsified and dispersed at 40 ° C. for 10 minutes using a homogenizer, and the resulting emulsion was stirred at 40 ° C. for 2 hours to remove ethyl acetate, and then the volatilized ethyl acetate coating water was added with water to make a coupler. A dispersion was obtained.

(Preparation of coating liquid for light and heat sensitive recording layer) The above capsule liquid C 6.5 parts The above coupler dispersion liquid 8 parts Gelatin (15% aqueous solution) 2 parts Water 4.5 parts The above light and heat sensitive recording layer coating A liquid was prepared.

(Preparation of Protective Layer Coating Liquid) Pigment: Aluminum hydroxide 3 parts Binder: 8% aqueous gelatin solution (absorption maximum 270 nm) 20 parts The above components are dispersed in a sand mill to form a protective layer coating liquid having an average particle size of 0.5 μm. Was prepared.

(Preparation of light and heat sensitive recording material) The above light and heat sensitive recording layer coating solution was applied with a fine paper wire bar so that the amount of azide applied was 0.5 g / m ² and dried at 50 ° C. A color forming layer was formed.

Next, the protective layer coating solution was coated on the light and heat sensitive recording layer so that the solid content was 2 g / m ² , and the temperature was 50 ° C.
And dried to obtain a light and heat sensitive recording material of the present invention.

Comparative Example 1 (Preparation of coating liquid for light and heat sensitive recording layer) A coating liquid for light and heat sensitive recording layer was prepared by the same formulation as in Example 1 (Preparation of coating liquid for protective layer) Pigment: Kaolin 3 parts Binder: 10% (1-Quinolino-2- (p-dimethylamino)) styrene-maleic acid copolymer ammonium salt (absorption maximum 320 nm) 30 parts Water 7 parts The above layers are dispersed in a sand mill to form a protective layer having an average particle size of 0.5 μm. A coating liquid was prepared.

(Preparation of light and heat sensitive recording material) After forming a light and heat sensitive recording layer with the same formulation as in Example 1, the solid content of the protective layer coating solution was 2 g / m ² on the light and heat sensitive recording layer. And then dried at 50 ° C. to obtain a light and heat sensitive recording material.

Comparative Example 2 (Preparation of Light and Heat Sensitive Recording Layer Coating Solution) A light and heat sensitive recording layer coating solution was prepared in the same formulation as in Example 2.

(Preparation of Protective Layer Coating Solution) A protective layer coating solution was prepared in the same formulation as in Comparative Example 1.

(Preparation of light and heat sensitive recording material) After forming a light and heat sensitive recording layer with the same formulation as in Example 2, a protective layer was formed on the light and heat sensitive recording layer with the same formulation as in Comparative Example 1, A light and heat sensitive recording material was obtained.

Comparative Example 3 (Preparation of Light and Heat Sensitive Recording Layer Coating Solution) A light and heat sensitive recording layer coating solution was prepared in the same formulation as in Example 3.

(Preparation of Protective Layer Coating Solution) A protective layer coating solution was prepared in the same formulation as in Comparative Example 1.

(Preparation of light and heat sensitive recording material) After forming a light and heat sensitive recording layer with the same formulation as in Example 3, a protective layer was formed on the light and heat sensitive recording layer with the same formulation as in Comparative Example 1, A light and heat sensitive recording material was obtained.

Comparative Example 4 (Preparation of Light and Heat Sensitive Recording Material) A light and heat sensitive recording material was obtained by forming a light and heat sensitive recording layer with the same formulation as in Example 1 and applying no protective layer.

Comparative Example 5 (Preparation of Light and Heat Sensitive Recording Material) A light and heat sensitive recording material was obtained by forming a light and heat sensitive recording layer with the same formulation as in Example 2 and coating no protective layer.

Comparative Example 6 (Preparation of Light and Heat Sensitive Recording Material) A light and heat sensitive recording material was obtained by forming a light and heat sensitive recording layer with the same formulation as in Example 3 and coating no protective layer.

[Coloring / Fixing Property Test] The obtained light and heat sensitive recording material was heated at 120 ° C. for 5 seconds (0.5 kg / m ² ) using a thermal gradient tester (manufactured by Toyo Seiki), and then subjected to high pressure. The entire surface was exposed for 30 seconds using a mercury lamp. After that, the white background is heated again at 120 ° C. for 5 seconds (0.5 kg / m ² ) and then the entire surface is exposed for 30 seconds using a medium pressure mercury lamp to measure the color density of the non-heated part and the first and second heated parts. did. Table 1 shows the results.

[0092]

[Table 1]

As is clear from the results of Table 1, Example 1,
Comparing Comparative Example 1 and Comparative Example 4, the color density of the heated portion during the first heating is almost the same in Comparative Example 4 and Example 1, but in Comparative Example 1, a decrease in color density is observed. Comparing the color densities of the heated portion at the time of the second heating, Comparative Example 4 and Example 1 are almost equal to each other, whereas Comparative Example 1 shows color development due to a decrease in fixing property.

The same can be said for the comparison between Example 2, Comparative Example 2 and Comparative Example 5, and the comparison between Example 3, Comparative Example 3 and Comparative Example 6 as well as the above-mentioned comparison.

From the above results, in the light and heat sensitive recording material of the present invention, no decrease in the color density of the heated recording portion due to the coating of the protective layer was observed, and the color density at the second heating was small, so that the fixing property was deteriorated. Is very small.

[Pencil Writability Test] Writing on the obtained light and heat sensitive recording material with a pencil, the writing quality, pencil paste, etc.
The density of B and H was measured respectively and evaluated in the following two stages.

◯: Writing can be done smoothly without applying pressure. In addition, the pencil is often glued and the density of the writing area is high. Δ: Writing is difficult unless some writing pressure is applied. The density of H is very difficult to write, and the tip of the writing instrument feels slippery and uncomfortable. In addition, the density of the writing area is not too high for practical use. ×: The writing tool is difficult to write smoothly even with considerable writing pressure. In addition, even if the pencil is poorly glued and the density of B is low, the density of the writing part is too thin to exceed the practically acceptable limit for general office use.

[Hand test] The obtained light and heat sensitive recording material was touched by 10 people who were involved in general office work (people who had handled facsimile paper), and a copy paper (Konica Copy Paper A- Four
NR-Aw (manufactured by Konica Corporation), and the touch was evaluated.

◯: 7 or more people evaluated the same touch Δ: 4 to 6 evaluated the same touch x: 3 or less evaluated the same touch.

The results of the pencil writability test and the hand touch test are shown in Table 2.
Shown in

[0101]

[Table 2]

As is clear from the above results, in Examples 1, 2 and 3 of the present invention and Comparative Examples 1, 2 and 3 in which the protective layer is applied, the pencil writing property and the touch property are good, but the protective layer is applied. In Comparative Examples 4, 5, and 6, which are not provided, it is understood that both the writability and the hand feel are poor.

From the results of the color-fixing test and the pencil writability test, the light and heat sensitive recording material of the present invention is excellent in writability and touchability without lowering the color density of the heat-recorded portion or the fixing property. It is clear that a good light and heat sensitive recording material was obtained.

[0104]

The light and heat sensitive recording material according to the present invention is a pencil or a pencil for protecting the color forming element from direct contact with the outside without impairing the action of light of the light and heat sensitive recording material, specifically, fixing property and color forming property. It has an excellent effect of writing and touch.

Front Page Continuation (72) Inventor Kenzo Nakazawa 1 Konica Stock Company, Sakura-cho, Hino City, Tokyo In-house (72) Inventor Tetsuya Yoshida 1 Konica Stock Company, Sakura-machi, Hino-shi, Tokyo In-house (Shuji Kida, Tokyo) 1st Sakura-cho, Tohino-shi Konica Stock Association In-house

Claims (3)

[Claims] 1. In a light and heat sensitive recording material having a recording layer for recording and fixing using heat and light on a support and a protective layer on the recording layer, the binder in the protective layer has a light wavelength of 300 to 300 nm. A light and heat sensitive recording material having no spectral absorption maximum at 400 nm. 2. The light and heat sensitive recording material according to claim 1, wherein the binder in the protective layer is a polyvinyl alcohol derivative. 3. The light and heat sensitive recording material according to claim 1, wherein the binder in the protective layer is a polypeptide derivative.