JPS602393A - Photosensitive thermal recording material - Google Patents

Abstract

PURPOSE:To obtain a novel photosensitive thermal recording material capable of forming a color in high density and fixing a non-recorded part, by a method wherein a hexaaryl-bi-imidazole capable of liberating an oxidizing agent under heat or light and an oxidation color forming dye precursor are applied to a base in an isolated condition. CONSTITUTION:A hexaaryl-bi-imidazole such as 2, 2'-bis(o-bromophenyl)-4, 4'- tetraphenylbiimidazole and a colorless dye precursor capable of forming a color in the presence of an oxidizing agent leberated from the hexaaryl-bi-imidazole, e.g., an aminotriarylmethane or aminoxanthene, are used in a mixing ratio of 10:1-1:10. The two components are applied to the base in an isolated condition by dispersing them in a particulate form into a binder such as ethyl cellulose and polyvinyl alcohol or by providing them in two layers, followed by drying. Preferably, the mixing ratio of the hexaaryl-bi-imidazole to the dye precursor is about 1:10.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to a light- and heat-sensitive recording material, and more specifically, a material that develops color using thermal energy such as a heat-sensitive head, a heat mode, or a laser beam, and further emits light. The present invention relates to a light- and heat-sensitive recording material which can be photofixed and which, when irradiated, develops color at a higher density in printed areas, loses its ability to develop color in non-printed areas, and does not develop color even when heat is applied again.

(Technical Background of the Invention) Conventional heat-sensitive recording materials include those that produce heat-sensitive coloring by utilizing a reaction between an organic acid metal salt and an organic reducing agent, a sulfur compound, an amine compound, etc. There are known devices that use a reaction with an acidic substance to develop heat-sensitive color. However, since such heat-sensitive recording materials do not have fixing performance, they cannot be prevented from being tampered with after recording. In addition, such recording materials are
When exposed to an environment of 0°C or higher, the entire surface often becomes colored, making it difficult to distinguish between records. In particular, heat-printed recording areas in heat-sensitive recording materials that utilize the reaction between leuco dyes and acidic substances have the disadvantage that they are erased when they come into contact with organic solvents or plasticizers in plastics. The above drawbacks are due to the inability of current heat-sensitive recording materials to fix.

On the other hand, as heat-sensitive recording materials that can be fixed, Japanese Patent Application Laid-Open No. 57-205190 and Japanese Patent Application Laid-Open No. 57-2082
No. 91 discloses a system in which a diazo compound, a coupler, and a basic substance are separated and coated, and then melted with heat and brought into contact to react, and a system in which the basicity is increased by heat and the diazo compound and coupler are reacted. A method of recording by producing diazo dye has been announced, but it lacks storage stability such as storage stability against humidity and heat, and there are also problems with the light resistance of the recording printed area. It has not been put into practical use for several reasons.

In addition, light and heat sensitive recording materials using diazosulfonate and couplers are described in JP-A-56-159641 and JP-A-56-164339, but the thermal energy required to develop color is large. It has not yet been put into practical use due to drawbacks such as slow color development and slow color development speed.

In addition, Photographic Science & Engineering (Photographic 5cien)
CE & Engineering) Volume 16 No. 6 (1
972) Nos. 433 to 442 of the same magazine, Vol. 23, No. 5 (1979), pages 287 to 289, hexaarylbiimidazole is radically dissociated by light, and this is a dye precursor. It is said that it causes the body to oxidize and develop color.

It has been found that the color development reaction rate in the solid phase of this system depends on the viscosity of the system at the time of radical generation.

An image forming method using this coloring mechanism is
As seen in Publication No. 19161 and Japanese Patent Publication No. 45-40150, etc., ■ hexaarylbiimidazole as a photo-oxidizing agent, ■ color development with ultraviolet light by a combination of triphenylmethane-based leuco dyes, and ■ oxidizing agent components such as quinone. A photosensitive composition for image formation is known in which visible light fixing is performed using a fixing agent component consisting of a redox couple consisting of a redox couple and a reducing agent component such as an alcohol or an ester.

Also, JP-A-55-156938, JP-A-56-1
As seen in JP-A No. 932, JP-A-56-8133, etc., a photocoloring agent basically contains (a') hexaarylbiimidazole as a photooxidizing agent and (b') an oxidative coloring leuco dye as a main component. layer and (C') cobalt (1)
Light- and heat-sensitive recording materials are known that consist of a fixing component generation layer formed by a combination of light and heat, which contains ammine complexes and photoreducing agent components as main components, but in both image forming methods, colors are developed with ultraviolet light and visible light (and heat). Fixing requires a fixing agent such as a redox couple or a base generating substance.

(Objective of the Invention) An object of the present invention is to provide a novel light and heat sensitive recording material which is completely different from the conventional light and heat sensitive recording materials as described above. That is, some of the specific properties of the novel light- and heat-sensitive recording material according to the present invention are as follows.

(1) By applying thermal energy according to the signal, it is possible to develop a vivid color of your choice, and by further irradiating the printed area with a higher color density, the non-printed area is fixed. It will not develop color even if it is heated again.

(2) The printed area colored by thermal energy will not be erased even if it comes into contact with a solvent or a plasticizer in plastic.

(Structure of the Invention) The present inventors have discovered that when the hexaarylbiimidazole and the oxidative color-forming dye precursor are physically separated, no color is developed by visible light, ultraviolet rays, or heat; He discovered that when one or both components melt and come into contact with each other through heating, they develop a color, and that if the color developed in this way is further irradiated with ultraviolet rays, the color development is further enhanced.Based on this discovery, he developed this book. Completed the invention.

That is, the present invention provides (a) a hexaarylbiimidazole that releases an oxidizing agent by heat or light; and (b)
It is obtained by applying and drying a coating agent containing as an essential component a substantially colorless dye precursor that develops color by reaction with the oxidizing agent, and which is obtained by applying and drying the above-mentioned (a). This is a light and heat sensitive recording material characterized in that the component (b) and the component (b) are in an isolated state at room temperature.

The configuration of the present invention will be explained in detail below.

<Hexaarylbiimidazole> Examples of the hexaarylbiimidazole used in the present invention are as follows.

2,2'-bis(0-bromphenyl)-4,4'-tetraphenylbiimidazole, 2,2'-bis(0-chlorophenyl)-4,4',di-1-naphthyl-5,5' -diphenylbiimidazole, 2,2'-bis(0-lytetraluphenyl)-4,4',5
・57-tetraphenylbiimidazole, 2,2'-bis(0-chlorophenyl)-4,4',5,5'-tetrakis(p-methoxyphenyl)biimidazole, 2,2'-bis(0- Chlorphenyl)-4・4′・5
・5'-tetrakis(m-methoxyphenyl)biimidazole, 2,2'-his(2,4-dichlorophenyl)-4,4
',5,5'-tetraphenylbiimidazole, 2,2'-bis(2,3-dimethoxyphenyl)-4,
4', 5, 5'-tetraphenylbiimidazole, 2, 2'-his(2, 4-dimethoxyphenyl)-4,
4′-5・5′-tetraphenylbiimidazole, 2・2′-his(0-ethoxyphenyl)-4φ4′・
5,5'-tetraphenylbiimidazole, 2-2'-
His(0-fluorophenyl)-4-4', 5, 5'-
Tetraphenylbiimidazole, 2,2'-His(0-
methoxyphenyl)-4,4'-bis(p-methoxyphenyl)-5,5'-diphenylbiimidazole, 2,2'-bis(0-methoxyphenyl)-4,4'.
5,5'-tetraphenylbiimidazole, 2,2/
-His(0-methoxyphenyl)-4・4′-5・5′
-Tetrakis(p-methoxyphenyl)biimidazole, 2,2'-bis(2,4,6-trimethylphenyl)-
4,4',5,5'-tetraphenylbiimidazole, 2,2'-di-1-su7thi-4,4',5,5'-tetraphenylbiimidazole, 2,2'-di-1-naphthyl -4・4′・5・5′〜tetrakis(p-methoxyphenyl)biimidazole, 2・2′−di9−7 enantory 4・4′=5・
5'-tetraphenylbiimidazole, 2,2'-di9-7 enantory-4,4',5,5'-tetrakis(p-methoxyphenyl)biimidazole, 2,2',4,4'-tetra -1-naphthyl-5.57
-diphenylbiimidazole, 2,2'-4,4'-tetrakis(0-methoxyphenyl)-5,5'-diphenylbiimidazole, 2,2'
-di-o-tolyl-4,4',5,5'-tetraphenylbiimidazole, 2,2',4,4',5,5'-hex-1-naphthylbiimidazole, 2,2',4・4', 5, 5'-hex-o-tolylbiimidazole, 2, 2', 4, 4', 5, 5'-hexakis(0-methoxyphenyl)biimidazole, 2, 2', 4, 4', 5, 5' ~ hexaphenyl biimidazole, 2, 2'-his(p-methoxyphenyl)-4, 4',
5,5'-tetraphenylbiimidazole.

<Dye Precursor> In the present invention, the substantially colorless dye precursors that develop color by reaction with the oxidizing agent generated from hexaarylbiimidazole include a) aminotriarylmethane having resistance to color development by air oxidation; Aminotriarylmethanes having an alkyl group, an alkoxy group or a halogen atom ortho to the methane carbon in at least two of the rearyl groups are preferred in terms of their superiority.

b) Aminoxanthine C) Aminothioxanthine d) Amino-9,10-dihydroacridine e) Aminophenoxazine f) Aminophenothiazine g) Aminodihydrophenazine h) Aminodiphenylmethane i) Aminohydrocinnamic acid (cyanethane) D I.
Mention may be made of 4-:)amino-2,3-dihydroanthraquinone.

For example, (a) above will be specifically described as a leuco dye suitable for use in the present invention.

Bis(4-diethylamino-0-tolyl)phenylmethanetris(4-diethylamino-0-tolyl)methanebis(4-diethylamino-0-tolyl)(p-benzylthiophenyl)methanebis(4-diethylamino-0-tolyl)( 3,4-dimethoxyphenyl)methanebis(p-diethylamino-o-lyl)(p-α-methoxyacetamidophenyl)methanebis(p-diethylamino-0-tolyl)(p-α-methoxyacetamido-m-methoxyphenyl) Methane bis(p-diethylamino-o-)lyl)(p-n-octaamido-m-methoxyphenyl)-methanetriarylmethane is used as a salt of a strong acid.

Examples of strong acids are mineral acids such as hydrochloric acid, hydrobromic acid, sulfuric acid, nitric acid, phosphoric acid; organic acids such as acetic acid, oxalic acid, p-)luenesulfonic acid, trichloroacetic acid, trifluoroacetic acid, perfluorohebbutanoic acid; dotesylbenzenesulfonic acid, and Lewis acids such as zinc chloride, zinc bromide, and ferric chloride, the proportion of acid usually being 0.33 mole to 1 mole per amino group.

As used herein, the term "strong acid" is defined as an acid that forms a salt with anilinoamino groups.

The mixing ratio of the hexaarylbiimidazole and the substantially colorless dye precursor is in the range of 10:1 to 1:10 molar ratio, preferably around 2:1.

Adhesive> The adhesive that can be used in the present invention is preferably a film-forming polymer. Specific examples thereof are as follows, but the invention is not limited thereto, and any film-forming polymer can be used. Ethylcellulose, polyvinyl alcohol, polyvinyl chloride, polystyrene, polyvinyl acetate, poly(methyl, propyl or butyl) methacrylate, cellulose acetate, cellulose acetate butyrate, cellulose nitrate, chlorinated rubber, polyvinyl butyral, polyvinylidene chloride/acrylonitrile , gelatin, and styrene-acrylic copolymer.

The mixing ratio of the total weight of hexaarylbiimidazole and substantially colorless dye precursor to the binder is 10:1.
~1:100 weight ratio, preferably 1:10
It is near .

<Isolation state> In the present invention, (a) hexaarylbiimidazole which releases an oxidizing agent by heat or light, and (b) a substantially colorless state that develops due to the reaction between the oxidizing agent generated from hexaarylbiimidazole. The state in which the dye precursor is isolated at room temperature is (1) component (a) in the adhesive layer.

middle) are dispersed in fine particles. (2) Laminating a first layer containing component (a) and a second layer containing component (b). C can be obtained by the following method.

Support> The photosensitive and heat-sensitive layer of the present invention is usually coated or impregnated onto a support. Specific examples of supports that can be used in the present invention are as follows.

Paper or synthetic paper such as art paper, coated paper, high quality paper, medium quality paper, baryta paper, etc. Plastic films such as polyester, polypropylene, polyethylene, polyvinyl acetate, polymethyl methacrylate, polyvinyl chloride, etc.

Production method> The light and heat sensitive recording material of the present invention can be prepared by mixing the above-mentioned components (a) and (b) with a suitable adhesive, coating or impregnating a support with the resulting composition; It can be manufactured by drying.

(Method of Use) When using the light- and heat-sensitive recording material of the present invention, the first method is to apply heat to the area where color development is desired, or to develop a primary color by applying heat, ultraviolet rays, or visible light. Next, the entire surface of this recording material is irradiated with ultraviolet rays or visible light to fix the non-colored areas, and at the same time, the intended purpose is achieved by making the areas that have already developed the primary color more intensely colored. Can be done.

The second method is to first irradiate the area you want to fix with ultraviolet rays or visible light to fix the non-colored areas, and then apply heat or heat and ultraviolet rays or visible rays to the entire surface to achieve the desired purpose. can do.

(Example) In order to explain the present invention in more detail, examples are shown below. Parts in the examples indicate parts by weight.

Example 1 A coating solution consisting of the following components was prepared.

Water 100 parts 2#2'-bis(0-lytetraphenyl)-4, 4', 5
・5'-tetraphenylbiimidazole (mp202℃
) 2 parts tris(4-diethylamino-o-)lyl)methane 1
Part 1) -Toluenesulfonic acid 1 part Polyvinyl alcohol (Nippon Gosei Kagaku Kogyo: NM-11
After dispersing 300 parts of the above coating solution in a ball mill for 16 hours, it was applied to a 40 g/z" high-quality paper to a solid content of 51/m", and was dried with air to give a solid content of 80 g/z.
Dry at °C.

A hot plate at 175° C. was pressed at 3 kg/m' for 5 seconds on the treated paper. A blue color was obtained on a pale yellow background. The optical density was measured with an optical densitometer and was 0.20. This was further exposed for 30 seconds from a distance of 1 m using a 2 kW ultra-high pressure mercury lamp, and the optical density of the blue image was measured to be 0.30. Even when heated with ultraviolet rays, the color did not develop and was completely fixed. Even when methanol was attached to this blue image, no change occurred.

Example 2 A recording material was prepared in the same manner as in Example 1 except that 3 parts of stearamide was added to the coating solution in Example 1, and was heated and recorded in the same manner and fixed with ultraviolet rays. As a result of measuring the optical density, a blue image of 049 in the recorded area and 0.09 in the non-recorded area was obtained.

Example 3 A recording material was prepared in the same manner as in Example 2, except that benzoylleucomethylene blue was used in place of tris(4-dimethylamino-0-tris)methane, and heat recording and ultraviolet fixing were carried out in the same manner. As a result of measuring the optical density, a blue image was obtained with a recording area of 0.90 and a non-recording area of 0.08.

Example 4 2,2'-bis(0-chlorophenyl)-4,4',5
・5'-tetraphenylbiimidazole (mp 2 (1
The procedure was the same as in Example 2, except that 2,2'-bis(p-methoxyfer)-4,4',5,5'-tetraphenylbiimidazole (m9127°C) was used instead of 2'C). A recording material was prepared using the same method, and the material was heated and recorded in the same manner and fixed using ultraviolet light. Recording area of optical density measurement: 0.70
, a blue image with a non-recorded area of 0.10 was obtained.

(Effects of the Invention) The present invention simply supports a coating agent containing a predetermined ratio of hexaarylbiimidazole and a dye precursor, and transfers thermal energy, light energy, By applying ultraviolet energy and irradiating ultraviolet rays or visible light, it is possible to develop a deep color in the recorded area and fix the non-recorded area, and the resulting recorded area comes into contact with organic solvents and plasticizers. It has the effect of not decoloring even if it is used.

Applicant: Oji Paper Co., Ltd. Agent: Patent Attorney Minoru Isaka

Claims (1)

[Scope of Claims] A paint containing as essential components (a) a hexaarylbiimidazole that releases an oxidizing agent by heat or light, and (b) a substantially colorless dye precursor that develops color by reaction with the oxidizing agent. 1. A light- and heat-sensitive recording material, which is obtained by applying a coating agent to a support and drying the material, and is characterized in that the components (a) and (b) are in a separated state at room temperature.