JPS59115890A - Heat sensitive recording material - Google Patents

Abstract

PURPOSE:To provide the titled material excellent in preservability and capable of fixing an image by irradiating ultraviolet rays after thermal printing, obtained by successively laminating a water soluble resin layer, a leuco dye layer, a layer comprising a resin mixture consisting of ultraviolet ray curable resin and thermosetting resin and a developer layer onto a support. CONSTITUTION:A water soluble resin layer (e.g., a PVA layer), a leuco dye layer (e.g., a 3-diethyl-6-chroro-7-anilinofluorane layer), a layer comprising a resin mixture consisting of ultraviolet ray curable resin (e.g., polyvinyl cinnamate) and thermosetting resin (e.g., polyester acrylate) and a developer layer (e.g., a bisphenol-A layer) are successively laminated to a support to obtain an objective recording material. EFFECT:The ultraviolet ray curable resin is polymerized by irradiating ultraviolet rays, the developer layer and the leuco dye layer are completely separated, a color is not formed even by re-heating and excellent image reliability is obtained. In addition, an image is not discolored by an org. solvent or a plasticizer.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a heat-sensitive recording material that utilizes a color-forming reaction between a leuco dye and a color developer, and particularly to a heat-sensitive recording material that has excellent image reliability.

[Prior art]

A thermosensitive recording material is a recording material with a structure in which a so-called thermosensitive coloring layer that develops color when heated is formed on a support such as paper, synthetic paper, or resin film, and has a built-in thermal head for heating the coloring chamber. A thermal printer or the like is used. Compared to other recording materials, such recording materials can produce records in a relatively short time without complex processes such as development and fixing, and do not generate noise.
Due to its relatively low cost, it is widely used not only for copying books, documents, etc., but also as a recording material for various information and measuring instruments such as electronic computers, facsimiles, telex machines, and medical measuring instruments.

There are various types of heat-sensitive recording materials, such as dye types, metal types, and silver salt types. Dye types are often used for reasons such as image clarity, whiteness of the background, naturalness, and relatively low cost.

However, dye-type heat-sensitive recording materials have problems such as colored images disappearing with organic solvents and non-image areas developing color when heated, and are used in fields where reliability is important, especially securities, receipts, etc. has not been adopted. In addition, there has been a growing demand for improved reliability of heat-sensitive recording materials.

〔the purpose〕

Therefore, the present invention aims to eliminate the above-mentioned drawbacks and provide a dye-type heat-sensitive recording material with improved reliability.

〔composition〕

According to the present invention, a water-soluble resin layer, a leuco dye layer, a mixed resin layer of an ultraviolet curable resin and a thermosetting resin, and a color developer layer are laminated in this order on a support. A heat-sensitive recording material is provided.

In the heat-sensitive recording material of the present invention, since the color developer layer and the leuco dye layer are separated by a mixed resin layer of an ultraviolet curable resin and a thermosetting resin, it has excellent storage stability and After heating and printing with RAD, etc., when irradiated with ultraviolet rays, the ultraviolet curable resin hardens, and the leuco dye layer and developer layer in the background are separated by the hardened and strong resin film, and then reheated. The color will not reappear. That is, the product of the present invention can fix the printed image by irradiating it with ultraviolet rays after heating printing. Moreover, in the product of the present invention, since the thermosetting resin in the printed area before UV irradiation has been cured after thermal coloring, the developer and leuco dye are strongly combined and do not separate. The problem of image decolorization is eliminated.

The leuco dye layer used in the present invention contains conventionally known colorless dyes! , or light-colored leuco forms of various dyes shown below are applicable.

(a) Leuco compound of triphenylmethane dye represented by the following general formula: Rz (wherein Rx, Ry and Rz are hydrogen, hydroxyl group,...rogen, alkyl group, nitro group, amine group, dialkylamine group, (Allyl group.) Specific examples of the above leuco compounds are as follows.

3.3-bis(p-”methylaminophenyl)-phthalide 3.3-bis(p-0 methylaminophenyl)-6-dimethylaminophthalyl (also known as crystalline iolet lactone) 3.3- Bis(p-dimethylaminophenyl)-6-noethylaminophthalide P 3.3-Bis(p-dimethylaminophenyl)-6-chlorophthalide 3.3-Bis(p-dibutylaminophenyl)phthalide 1
5 (b) Fluoran dye C leuco compound represented by the following general formula: Rz In the formula, Rx, Ry and Rz are the same as in the case of (a) above. Specific examples of compound compounds are as follows. be.

3-Fuclohecylamino-6-chloromoran 3-(N,N-diethylamino)-5-methyl-7-(
N,N-dibenzylamino)fluoran 3-,)methylamino-5,7-dimethylfluoran 3-dimethylamino-7-methylfluoran 3-diethylamine-7,8-benzfluoran) fluoran dyes Leuco compound: 3-diethyl 7
Mi/-6-methyl-7-chlorofluoran 3-pyrrolidino-6-methyl-7-anilinofluoran 2-(N-(3'-)IJ chlorylmethylphenyl)amine)-6-dinithylamino Fluoranro 2-43
．． 6-Bis(diethylamino)-9-(o-chloroanilino))xantylbenzoic acid lactam 3-diethylamino-? -(o-chloroanilino)fluoran 3-dibutylamino-7-(o-chloroanilino)fluoran 3-N-methyl-N-amylamino-6-methyl-7-
Anilinofluoran (3-N-methyl-N-cyclohexylamino-6-methyl-7-anilinofluoran) A lactone compound represented by the following general formula: (X4)
n In the formula, R1 and R2 represent hydrogen, a lower alkyl group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted phenyl group, a cyanethyl group, or a β-...rogenated ethyl group, or When RI and R2 combine, ←CH2 sho, +CH2+-5 represents (7CH2h Of CH2 sho), R3 and R4 are hydrogen, lower alkyl group,
Alkyl group, amine group and phenyl group, R3
Any one of , X represents hydrogen, halogen, lower alkyl group and lower alkoxyl group, and n represents o-1 or an integer from 1 to 4.

Specific examples of the above compounds are as follows.

3-(2'-hydroxy-4'-dimethylaminophenyl) = 3-(2!/-methoxy-57-chlorophenyl)phthalide 3-(2'-hydroxy-47-dimethylaminophenyl)-3 -(2'-methoxy-5'-nitrophenyl)
Phthalide 3-(2'-hydroxy-47-dimethylaminophenyl)-3-(2'-methoxy-5-methylphenyl)phthalide 3-(2'-methoxy-4'-dimethylaminophenyl)-3-( 2'-hydroxy-47-chloro-5'-)
f-ruphenyl) phthalide, etc.

Conventionally known color developers can be used, but
Particularly preferred for use in the present invention are, for example, benzoic acid, salicylic acid, 3,5-quinlenol, thymol, P-tert-butylphenol, 4-hydroxyphenoxide, methyl-4-hydroxybenzoate, 4- HyP-roxyacetophenone, α-naphthol,
β-naphthol, catechol, resorcinol, hypoquinone, 4-tert-octylcatechol, 4,4'-8
eC-butylidenephenol, 2,2-dihydroxydiphenyl, 2,2'-methylenebis(4-mef-6-
jet-butylphenol), 2,2'-bis(4'
-Hydroxyphenyl)furono,4,4'-isopropylidene-bis(2-tert-butylphenol)
, 4+'' 5ee-butylidene diphenol, pyrogallol, phloroglucin-1, and 5ee-butylidene diphenol.

In the present invention, a mixed resin layer of an ultraviolet curable resin and a thermosetting resin is provided between the leuco dye layer and the color developer layer. As the ultraviolet curable resin in this case, various conventionally known ones can be employed, but particularly important ones include cinnamic acid derivatives, such as polyvinyl cinnamate,
Cinnamate ester of ethylene-vinyl alcohol copolymer, cinnamate ester of glyptal resin, cinnamoyl type polymer with styrene backbone, cinnamate ester of styrene-maleic anhydride copolymer, polyvinyl cinnamylidene acetate, Examples include polyvinylbenzalacetophenone, polyvinylstilketone, and spiran resin. However, an ultraviolet absorber can be added to the ultraviolet curable resin layer together with the ultraviolet curable resin. Examples of such ultraviolet absorbers include benzoin, benzoin methyl ether, benzophenone and its derivatives, 2-chloroanthraquinone, benzoyl-oxy-1, and the like.

In addition, as the thermosetting resin, various conventionally known ones,
For example, polyester acrylate, acrylate monomer, urethane acrylate, epoxy acrylate,
Examples include diacrylphthalate prepolymers and epoxy resins.

In the present invention, a water-soluble resin layer is provided between the support and the leuco dye layer, and various conventionally known water-soluble resins can be used as the water-soluble resin in this case, and representative ones include: For example, methylcellulose, hydroxyethylcellulose, carboxymethylcellulose, polyvinyl alcohol, carboxyl group-modified polyvinyl alcohol, polyvinylpyrrolidone, polyacrylamide r1 polyacrylic acid, starch and derivatives, casein, gelatin, alkali of styrene-maleic anhydride copolymer salts, alkali salts of iso(or diiso)butylene-maleic anhydride copolymers, and the like.

Further, if necessary, the above-mentioned water-soluble resin can be used in combination with an aqueous dispersion type polymer resin. Typical examples of this water-based dispersion polymer resin include polyvinyl acetate, vinyl chloride/
Examples include vinyl acetate copolymer, polyurethane, polyacrylic acid ester, styrene/butadiene/acrylic copolymer, polyester, and the like.

In the present invention, the water-soluble resin layer can also be provided on the upper surface of the leuco dye layer, if necessary.

A binder is usually applied to the leuco dye layer and the developer layer to firmly bond the layers to the support.
As the binder in this case, a conventionally used binder can be used, and for example, the water-soluble resin shown above can be used.

In the present invention, fillers may be added to each of the coating layers as necessary to improve head matching properties and writing properties.
Alternatively, a thermofusible substance or the like may be added to improve heat sensitivity and prevent pressure coloring. In this case, examples of fillers include calcium carbonate, magnesium carbonate, alumina, silica, talc, sulfurium sulfate, magnesium hydroxide, aluminum hydroxide, and fine particles such as styrene resin, fluororesin, urea, and formalin resin. I can do it. Examples of thermofusible substances include the following:

Animal waxes such as beeswax and shellac wax, vegetable waxes such as carna wax, mineral waxes such as montan wax, petroleum waxes such as graphite wax and microcrystalline wax, and high fatty acid content. Alcohol esters, higher amides.

Higher amines, condensates of fatty acids and amines, condensates of aromatic acids and amines, synthesis/grafine, chlorination/ξ roughhein,
Synthetic waxy substances such as higher linear glycols, 3,4-epoxy-dialkyl phthalate, and metal salts of higher fatty acids.

In the present invention, the thermofusible substance and filler are preferably contained in the water-soluble resin layer.

To obtain the heat-sensitive recording material according to the present invention, each layer-forming coating solution is prepared by dissolving or dispersing the above-mentioned dripping layer-forming components in a suitable solvent, and the coating solution is coated on a support, respectively.
dry. In this case, the solvent for dissolving or dispersing the layer-forming components is appropriately selected depending on the properties of the layer to be formed and the purpose of formation.

Incidentally, in order to achieve the object of the present invention effectively, a coating layer of a water-soluble resin may be provided on the back surface of the support.

〔effect〕

The product of the present invention uses ultraviolet light (
By irradiating the ultraviolet curable resin with light (as short as 500 mm), the resin polymerizes and the developer layer and leuco dye layer are completely separated, making it impossible to develop color even after reheating, resulting in a fixed record. Materials are obtained.

Furthermore, it is a stable recording material that does not cause images to be discolored by organic solvents or plasticizers.

〔Example〕

Next, the present invention will be explained in more detail with reference to Examples.

Example 1 (Liquid A) 3-diethyl-6-chloro-7-anilinofluorane 2
0 parts by weight 10 Hydroxy engineered cellulose water m liquid 20 rr
Water-60 A mixture having the above composition was ground and dispersed using a ball mill to prepare liquid A (leuco dye dispersion).

(Liquid B) Bisphenol A 20 parts by weight 10% hypohyroxyethyl cellulose aqueous solution 20
〃water
60 A mixture having the above composition was ground and dispersed in a ball mill to prepare liquid B (developer dispersion).

Next, polyvinyl alcohol (5cI0 aqueous solution) was applied and dried to 2y/m2 (solid content) on double-quality paper (50y/m2), and then the preparation solution A was applied and dried.
m2 (solid content). Furthermore, a mixed solution containing an ultraviolet curable resin [Spirac T-502, Showa Kobunshi @)] and a thermosetting resin (polyester acrylate) was applied and dried to give a density of 21/m2 (solid content).
On top of that, apply the preparation solution B as the top layer and dry it, 3y/
m2 (solid content) to obtain the heat-sensitive recording material of the present invention.

Example 2 This work was carried out in exactly the same manner as in Example 1, except that the preparation solution A of Example 1 was applied and dried, and then polyvinyl alcohol (5% aqueous solution) was applied and dried at a concentration of 2y/m2 (solid content). Obtained an invented heat-sensitive recording material.

Comparative Example 1 Ultraviolet curable resin used in Example 1 (Spirac T-5
A comparative heat-sensitive recording material was obtained in exactly the same manner as in Example 1, except that polyvinyl alcohol (5% aqueous solution) was used instead of the mixed solution containing 02) and a thermosetting resin (polyester acrylate).

Comparative Example 2 Ultraviolet curable resin used in Example 1 (Slack T-5
02) and a thermosetting resin (polyester acrylate), an ultraviolet curable resin (Spirac T
A heat-sensitive recording material for comparison was obtained in exactly the same manner as in Example 1, except that a solution containing only 502) was used.

Using the heat-sensitive recording material obtained as described above as a sample, using a thermal gradient tester [@Toyo Seiki Manufacturing Co., Ltd.], it was tested at 1, 50°C, and 2°C.
A colored image was obtained under the application conditions of Kg/cm2.1 seconds, and this was irradiated with light for 5 seconds using the exposure section of a diazo copying machine [Ricopy 5M-2000J (manufactured by Ricoh Co., Ltd.)]. In order to check the degree of fixation, the non-image area after the light irradiation was printed again under the same conditions as above and the color density was measured. Table 1 shows the results.
Shown below. As is clear from the results in Table 1, it can be seen that the heat-sensitive recording material of the present invention was fixed and had high image reliability.

, , , , , , , /'/' / Table 1 Print density: Macbeth RD-514 (filter w-t
Measured by 06).

Conditions for printing density after leaving for 7 days: normal temperature and humidity, storage in a dark place.

Patent applicant Ricoh Co., Ltd. Agent Patent Attorney Toshiaki Ikeura

Claims (1)

[Claims] (]) A heat-sensitive recording material characterized in that a water-soluble resin layer, a leuco dye layer, a mixed resin layer of an ultraviolet curable resin and a thermosetting resin, and a color developer layer are laminated in that order on a support. .