JPS59115889A - Heat sensitive recording material - Google Patents

Abstract

PURPOSE:To provide a heat sensitive recording material excellent in image reliability, obtained by successively laminating a leuco dye layer and a water soluble resin layer, an ultraviolet ray curable resin layer and a developer layer which respectively contain specific substances to a support. CONSTITUTION:A layer comprising a leuco dye [e.g. 3,3-bis(p-dimethylaminophenyl)-phthalide], a layer comprising water soluble resin (e.g., PVA) containing thermoplastic substance (e.g., shellac wax), a layer comprising ultraviolet ray curable resin (e.g., polyvinyl cinnamate) containing thermoplastic resin (e.g., polyester) and a developer layer containing aromatic metal caboxylate (e.g., metal salt of benzoic acid) and/or aromatic sulfide or sulfone [e.g., bis(4-hydroxyphenyl) sulfide] as a developer are successively laminated to a support (e.g., paper) to obtain an objective heat sensitive recording material.

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 having to undergo complicated processes such as development and fixing, and generate more 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.

Heat-sensitive recording materials include dye type and metal type.1. There are various types such as silver salt Taizo. 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 desire to improve the 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 leuco dye layer, a water-soluble resin layer, an ultraviolet curable resin layer, and a color developer layer are laminated in this order on a support, and the water-soluble resin layer contains a thermofusible substance and an ultraviolet curable material. The present invention provides a heat-sensitive recording material characterized in that the thermoplastic resin layer contains thermoplastic sulfone-EEJ.

In the heat-sensitive recording material of the present invention, the developer layer and the leuco dye layer are separated by the ultraviolet curable resin layer;
In addition to having excellent storage stability, when irradiated with ultraviolet rays after heating with a thermal head etc., the ultraviolet curable resin hardens, and the leuco dye layer and developer layer in the background part are hardened by the hardened resin film. Separated and will not recolor when reheated. 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 thermoplastic resin is mixed in the ultraviolet curable resin layer, the color developer layer provided on the ultraviolet curable resin layer is made uniform, and more complete layer separation is achieved. Preservability is improved. Furthermore, since aromatic carzenate metal salts and aromatic thioethers are used as color developers, the colored images are highly resistant to harmful chemicals and do not fade with organic solvents or plasticizers. Furthermore, since the leuco dye layer is protected by the water-soluble resin layer containing a thermofusible substance on top of it, it has good thermal responsiveness, and there is no penetration of organic solvents, which prevents skin coloring caused by organic solvents. Does not cause any problems.

using a mixture of Of course, if necessary, a conventional color developer can be used in combination within a range that does not particularly impede the purpose of the present invention. As the aromatic caldenic acid metal salt used in the present invention, for example, those represented by the following general formula (I) are employed.

R Ka1+! In the above formula, [A] represents a benzene ring or a naphthalene ring, and "I is an alkyl group, an aralkyl group, or hydrogen,
R and 2 represent a hydroxyl group, hydrogen or an alkyl group, and M represents a metal such as zinc, tin, nickel, magnesium, barium, calcium, aluminum, cobalt, copper, etc. For example, one represented by the following general formula (It) is employed.

A, r, = 5(-02,)n7Ar2(TI) In the above formula, ArI and A, r2 are aromatic groups, such as Eva, phenyl group, naphthyl group, hensyl group, diphenylmethyl group, Hydroxy group, alkyl group, halogen,
Included are phenyl groups, naphthyl groups, benzyl, diphenylmethyl, etc. whose nucleus is substituted with a substituent such as a cyclohexyl group. n is 0 or 1.

Examples of aromatic carzenate metal salts include benzoic acid,
3,5-di-t-butylsalicylic acid, 2-methylsalicylic acid, 4-methylsalicylic acid, 2-hydroxy-3-naphthoic acid, 5-1-octylsalicylic acid, 5-cumylsalicylic acid, 1-hypoquine-2- Zn such as naphthohydrochloric acid,
Sn, Oa, Mg, Ba.

AI! , N1, Co, Ou, etc., and use of zinc salt is particularly preferred.

Dimensions, Yoshijv≠# L -(Ha, Bis(4-hydroxyphenyl) sulfide, Bis(3-methyl-4-hydroxyphenyl) sulfide, Gisu(3+5M methyl-4
-hydroquinphenyl) sulfide, bis(2,3,5
-) dimethyl-4-hyP-roxyphenyl) sulfite,
His(3-sec-phthyl-4-hydroxyphenyl)sulfite, Bis(3-cyclohexyl-4-hydroxyphenyl)sulfite, 4-(diphenylmethyl)
Merca7' l-phenol, 1-(4'-chlorobenzyl)mercaptophenol, 4-hydroxy-4'-
For the leuco dye layer used in the present invention, conventionally known leuco forms of the various dyes shown below, usually colorless or light colored, are applied.

(a) Leuco compound R7゜ of triphenylmethane dye represented by the following general formula (where RX + Ry and Rz are hydrogen, hydroxyl group, halogen, alkyl group, nitro group, amine group, dialkylamino group, allyl group ) Specific examples of the above leuco compounds are as follows.

3.3-bis(p-1 methylaminophenyl)-phtallyP 313-bis(p-07 thylaminophenyl)-6-dimethylaminophthalide (also known as crystal violet lactone) 3.3-bis(p -dimethylaminophenyl)-6-dibutylaminophenyl 313-bis(p-1methylaminophenyl)-6-chlorophthalide313-bis(p-dibutylaminophenyl)phthalide (b) Fluoran dye represented by the following general formula Leuco compound: Z In the formula, Rx + RY and Rz are the same as in the case of 0) above.

Specific examples of the above compounds are as follows.

3-7 Chlohequinylamino-6-chlorofluorane 3-(N,N-diethylamino)-5-methyl-7-(
N,N-dibenzylamino)fluoran 3-)methylamino-5,7-dimethylfluoran 3-)methylamino-7-methylfluoran 3-)ethylamino-7,8-benzfluoran (c) Leuco compound of fluoran dye: 3-diethylamino-6-)f-7-chlorofluoran 3-pyrrolidino-6-methyl-7-anilinofluoran 21+">(3'=t'J fluoromethylphenyl ) amine)-6-dinithylaminofluorane 2-(3,6-
Bis(diethylamino)-9-(0~chloranilino)
) Xanthylbenzoic acid lactam 3-diethylamino-7-(0-chloroanilino)fluoran 3-dibutylamino-7-(o-chloroanilino)fluoran 3-N-methyl-N-amylamino-6-methyl-7-
Anilinofluoran (3-N-methyl-N-cyclohexylamino-6-methyl-fuanilinofluoran) A lactone compound represented by the general formula below. It represents a substituted aralkyl group, a substituted or unsubstituted phenyl group, an anoethyl group, a β-halogenated ethyl group, or a combination of 几l and 戊, 0H2-)4. (aH2→5
or (CII2→20 soc T, T2→2,
R3 and electron represent hydrogen, a lower alkyl group, an alkyl group, an amino group or a phenyl group, one of the islands and R4 is hydrogen, X1+ X2 and X3 are hydrogen, a lower alkyl group, a lower alkoxyl group, represents a halogen atom, a halogenated methyl group, a nitro group, an amine group, or a substituted amine group; X4 represents hydrogen, a halogen, a lower alkyl group, or a lower alkoxyl group; n is 0 or 1 to 4; Represents an integer.

Specific examples of the above compounds are as follows.

3- (2'-Hydroxy-4'-dimethylaminophenyl) -3-(2'-methoxy-5'-chlorophenyl) phthalide 3-(2'-hydroxy-4'-dimethylaminophenyl) -3- (2'-methoxy-5'-nitrophenyl)
Phthalide 3-(2'-hyProxy4'-diethylaminophenyl)-3-(2'-methoxy-5-methylphenyl)phthalide 3-(2'-methoxy-4'-dimethylaminophenyl)-3- (2'-hydroxy-41-chloro-5'-methylphenyl)phthalide and the like.

In the present invention, an ultraviolet curable resin layer containing a thermoplastic 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 nonnamate,
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, Sugiran resin, and the like. Moreover, 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 n
4 bodies, 2-chloroanthraquinone, benzoyl? -Oquindo et al.

In addition, as a thermoplastic resin, polyester 1.1-?
Polyvinyl acetate, polymethyl methacrylate, cellulose acetate zotylate, polyvinyl methyl ether, polyurethane, ketone resin, petroleum resin, coumaron, Kuchi-shin, toluene sulfonamide resin, vinyl chloride/maleic acid copolymer resin, polycaprolactone, etc. Examples include resins, and those that dissolve in ultraviolet curable resins are preferable. The ratio of thermoplastic resin and ultraviolet curable resin is 1 part by weight of ultraviolet curable resin, thermoplastic resin 001-03
If the thermoplastic resin is less than 0.001 parts by weight, the ultraviolet curable resin and the color developer will mix, resulting in insufficient layer separation, which is undesirable. , 03 parts by weight, the ultraviolet curable resin will not be sufficiently cured by ultraviolet irradiation, resulting in unsatisfactory fixing.

In the present invention, a water-soluble resin layer containing a thermofusible substance is provided between the leuco dye layer and the ultraviolet curable resin layer. Typical examples include methylcellulose, hydroxyethylcellulose,
Carboxymethyl cellulose, hollyhinyl alcohol,
Cardixyl group-modified polyvinyl alcohol, polyvinylpyrrolitone, polyacrylamide, polyacrylic acid, starch and derivatives, casein, gelatin, alkali salts of styrene-maleic anhydride copolymer, in(or diiso)butylene-maleic anhydride copolymer Examples include alkali salts of polymers. Various conventionally known thermofusible substances can be employed, and examples 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 chisel rough-in wax and microcrystalline wax, and polyvalent higher fatty acids. Alcohol esters, higher amides.

Higher amines, condensates of fatty acids and amines, condensates of aromatic acids and amines, synthesis/ξ rough-in, chlorination/ξ rough-in,
Synthetic waxy substances such as higher linear glycols, dialkyl 3,4-epoxy-hexahydrophthalates, metal salts of high R fat H, etc.

The thermofusible substance may be added in an amount of 0.0% to 1 part by weight of the water-soluble resin.
It is preferably used in a range of 0.05 to 0.02 parts by weight. It's Kade.
These thermofusible substances can be included in other coating layers as well, 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, conventionally used binders can be used, for example, the water-soluble resins mentioned above can be used.

In the present invention, a filler may be added to each of the above-mentioned coating layers, if necessary, in order to improve head matching properties and writability. In this case, the filler may be, for example,
Fine particles of calcium carbonate, magnesium carbonate, alumina, silica, talc, barium sulfate, magnesium hydroxide, aluminum hydroxide, styrene resin, fluororesin, urea/polma/phosphorus resin, etc. can be cited.

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 effectively achieve the object of the present invention, a direct 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 it with light (wavelength shorter than 500 nm), the ultraviolet curable resin polymerizes, completely separating the developer layer and the leuco dye layer, making it impossible to develop color even after reheating, and fixing the fixed recording material. is obtained.

It is a stable recording material that does not erase the color of stale images with organic solvents or plasticizers.

〔Example〕

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

Example I Solution A N-octadenlecarnogmoylbenzene
1 Polyvinyl alcohol (10% aqueous solution)
1o water
87 Dispersion A was prepared by dispersing the above composition for 24 hours using a Sho-lumil.

B liquid 4-el-'oki'-4'-ri°0) 71=Refur 7
8 parts by weight of amyl stearate 15 1
〃Calcium carbonate
2 Polyvinyl alcohol (10% aqueous solution)
3o water
59 parts by weight of the above composition using a Zeel mill,
Dispersion B was prepared by dispersing for 24 hours.

Liquid C゛Silica fine powder 5
〃Polyester resin 1
o ”benzophenone
3. Using the above composition with an attritor, 5
Dispersion liquid C was prepared by dispersing in the dark for a period of time.

The above Preparation Solution A was applied onto high quality paper (approximately 50 g/rn2) and dried to give a concentration of 2 g/rn2 (solid content). Next, a solution prepared by dispersing 0.5 g of amyl stearate F in 100 g of a 7% aqueous solution of polyvinyl alcohol was applied onto this coating layer and dried to give a coating composition of 5 g/rr? '
(solid content). Next, liquid C was applied onto this coating layer to form a coating layer of 2 g/r+12. Next, liquid B was applied onto this coating layer and dried to a concentration of 3 g/m2 (solid content) to obtain a heat-sensitive recording material of the present invention.

Example 2 4-Hydroxy-4'-chlorodiphenylsulfur+≠ of Solution B of Example 1! pK, 3.5 - A heat-sensitive recording material of the present invention was obtained in the same manner as in Example 1 except that zinc t-diptylsalicylate was used.

Example 3 In place of the ultraviolet curable resin (trade name: Aronix 8030) in Liquid C of Example 1, a different type of resin (trade name: Spirasoku 3151 (manufactured by Showa Kobunshi)) was used, and styrene was used instead of the polyester resin. A heat-sensitive recording material of the present invention was obtained in the same manner as in Example 1 except that -vinyltoluene copolymer resin was used.

Example 4 Instead of 3-N-methyl-N-cyclohexylamino-6-methyl-7-anilinoneluorane in Solution A of Example 1, 3-di-n-butylamino-7-(o-chloroanilinoluorane) was used. ) A heat-sensitive recording material of the present invention was obtained in the same manner as in Example 1 except that fluorane was used and zinc B acid was used.

Comparative Example 1 A comparative heat-sensitive recording material was obtained in the same manner as in Example 1 except that 4-hydroxy-4'-chloro of the OB solution was used.

Comparative Example 2 A comparative heat-sensitive recording material was obtained in the same manner as in Example 2 except for the stearamide-containing polyvinyl alcohol layer on the leuco dye layer.

Comparative Example 3 A comparative heat-sensitive recording material was obtained in the same manner as in Example 1 except for the polyester resin of liquid C in Example 1.

The heat-sensitive recording material obtained as described above was tested at 150°C for 2 hours using a thermal gradient tester [Newly manufactured by Toyo Seiki Co., Ltd.].
A colored image was obtained under the application conditions of Kg/J for 11 seconds, and this was irradiated with light for 20 seconds using the exposure section of a diazo copying machine "Recopy 5M-2000J [manufactured by Ricoh]. After irradiation, the L image area was reprinted under the same conditions as above to determine the color density.

The results are shown in Table-1. As can be seen from the results shown in Table 1, the heat-sensitive recording material of the present invention has a fixed, high-density image, and is therefore a highly reliable heat-sensitive recording material.

Table 1 Notes (1) Macbeth Densitometer rtD-514 was used for concentration measurement.

(2) Alcohol resistance was determined by adding 0.02 drops of ethyl alcohol (grade 1 reagent) to both the image area and the background area, and measuring the concentration of the dropped area after air drying using a Macbeth densitometer R, D-514.

536

Claims (1)

[Claims] (]) A leuco dye layer, a water-soluble resin layer, an ultraviolet curable resin layer, and a color developer layer are laminated in that order on a support, and the water-soluble resin layer has a thermofusible substance and an ultraviolet curable resin layer. 1. A heat-sensitive recording material, characterized in that the material contains a thermoplastic resin.