JPS59115891A - Heat sensitive recording material - Google Patents

Abstract

PURPOSE:To provide the titled material excellent in storage stability 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 thermoplastic substance-containing water soluble resin layer, an ultraviolet ray curable resin layer and a developer layer to a support. CONSTITUTION:A water soluble resin layer (e.g., a PVA layer), a leuco dye layer (e.g., a 3-cyclohexylamino-6-methyl-7-anilinofluorane layer), a water soluble resin layer (e.g., a PVA layer) containing thermoplastic substance (e.g., dialkyl 3,4- epoxy-hexahydrophthalate), an ultraviolet ray curable resin layer (e.g., a polyvinyl cinnamate layer) and a developer layer (e.g., a bisphenol-A layer) are successively laminated to a support to obtain an objective recording material. EFFECT:This recording material is cured by irradiating ultraviolet rays, the developer layer and the lueco dye layer are completely separated, a color is not formed even by re-heating and excellent image reliability is obtained.

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]

Thermosensitive recording materials have a so-called thermosensitive coloring layer that develops color when heated on a support such as paper, synthetic paper, or resin film.
A thermal printer or the like with a built-in thermal head is used to heat the recording material for color development. Compared to other recording materials, such recording materials can produce records in a relatively short time without complex processes such as development and fixing, do not generate noise, and are relatively inexpensive. Due to these advantages, 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, facsimile 7mm, telex, medical measuring instruments, etc.

There are various types of heat-sensitive recording materials such as dye type, metal type, and silver salt type. 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 water-soluble resin layer containing a thermofusible substance, an ultraviolet curable resin layer, 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 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. However, in the product of the present invention, since a water-soluble resin layer containing a thermofusible substance is provided between the color developer layer and the leuco dye layer, organic solvents may not penetrate into the leuco dye layer. This prevents the problem of background coloration due to organic solvents, and when printing with heat, the product has good thermal responsiveness and images with high color density can be obtained.

For the leuco dye layer used in the present invention, leuco bodies of various conventionally known colorless or light-colored dyes shown below are applied.

(a) Leuco compound of triphenylmethane dye represented by the following general formula 2 (where Rx, R7 and 2 are hydrogen, hydroxyl group, halogen, alkyl group, nitro group, amine group 1, dialkylamine group, It is an allyl group.) Specific examples of the above leuco compound are as follows.

3.3- His(p-)methylaminophenyl)-phthalide 3.3- His(p-dimethylaminophenyl)-6-
Dimethylaminophthalide (also known as crystal guiolet lactone) a,3-His(p-dimethylaminophenyl)-6-
diethylaminophthali 1:″ 3.3-bis(p-dimethylaminophenyl)-6-chlorophthalide 3.3-bis(p-dibutylaminophenyl)fucryl
(b) A fluoran dye leuco compound represented by the following general formula: R,z where RX, R, y and Rz are the same as in (a) above.

Specific examples of the above compounds are as follows.

3-chlorohekynylamino-6-chlorofluorane 3-(N,N-diethylamino)-5-methyl-7-(
N,N-,9benzylamino)fluoran 3-dimethylamine-5,7-dimethylfluoran 3-dimethylamino-7-methylfluoran 3-diethylamine-7,8-benzfluoran (c) Fluoran dye Leuco compound: 3-) ethylamino-6-
Methyl-7-chlorofluorane 3-pyrrolidino-6-methyl-7-anilinofluorane 2- (N-(3'-1-lifluoromethylphenyl)amino l-6-)ethylaminofluorane 2- (
3,6-Bis(diethylamino)-9-(0-chloroanilino))xantylbenzoic acid lactam 3-diethylamino-7-(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 (d) A lactone compound represented by the following general formula.

In the formula, R and R2 represent hydrogen, a lower alkyl group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted phenyl group, an anoethyl group, or a β-halogenated ethyl group, or is combined with +CI(23
-4+': 0IT2') 5 still (-c112+2
o (Represents 70H2+2, R3 and 4 are hydrogen,
A lower alkyl group, an alkyl group, an amino group or a phenyl group, and one of 几3 and 几4 is hydrogen,
Xl, X2 and X3 represent hydrogen, a lower alkyl group, a lower alkoxyl group, a halogen atom, a halogenated methyl group, a nitro group, an amine group, or a substituted amine group,
X4 represents hydrogen, halogen, a lower alkyl group or a lower alkoxyl group, and n represents 0 or an integer of 1-4.

Specific examples of the above compounds are as follows.

3- (2'-hyProxy47-dimethylaminophenyl) -3-(2'-methquine-57-chlorophenyl)phtaliF 3- (2'-hydroquine-47,)methylaminophenyl) -3 -(2'-Methoxy-5'-nitrophenyl)phthari F 3- (2'-hydroxy-4fudinitylaminophenyl) -3-(2'-methoxy-5-methylphenyl)phthari 1:' 3 - (2'-Me)xy-4'-dimethylaminophenyl) -3-(2'-hydroxy-4'-chloro-5
fumethylphenyl) phthalide, etc.

Conventionally known color developers are still applicable, but
Particularly preferred for use in the present invention are, for example, benzoic acid, salicylic acid, 3,5-kynol, thymol, P tert-7' tylphenol, 4-hydroxyphenoxy P1 methyl-4-1::l''D xybenzoate, 4-hypoquina-1= l-phenone, α
- Naphthol, β-naphthol, catechol, resorcinol, hypoquinone, 4-1erl~octylcatechol, 4.4'-5ec-butylidenephenol, 2.2-
) hydroquine, ) phenyl, 2,2'-methylenebis(
4-methyl-6-1crt-butylphenol), 2.
2'-bis(4'-150quinphenyl)furopane,
Examples thereof include 4.4'-(noprohyritenebis(2-1crl-butylphenol)), 4.4"sec-butylidenephenol, pyrogallol, and phloroglu7.

In the present invention, an ultraviolet curable resin layer 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-ginyl alcohol copolymer, cinnamate ester of gripkur resin, cinnamoyl-type polymer with styrene as a backbone, cinnamate ester of styrene-maleic anhydride copolymer, streamer Examples include vinyl cinnamylidene acetate, polyvinyl benzalacetophenone, polyvinyl stil ketone, 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,
-chloroanthraquinone, pendylamide oxide, and the like.

In the present invention, a water-soluble resin layer is provided between the support and the leuco dye layer, and a water-soluble resin layer containing a thermofusible substance is provided between the leuco dye layer and the ultraviolet curable resin layer. As the water-soluble resin in this case, various conventionally known ones are used, and representative examples thereof include methylcellulose-stilcellulose, polyhinyl alcohol, carboxylic group-modified polynyl alcohol, and polyvinylpyrrolidone. , polyacrylamide, 7I-soriacrylic acid, starch and derivatives, casein, gelatin, alkali salts of styrene-maleic anhydride copolymer, alkali salts of iso(or diiso)butylene-maleic anhydride copolymer, etc. Can be done.

If necessary, the above-mentioned water-soluble resin can be used in combination with an aqueous dispersion type polymer resin. Typical examples of this aqueous dispersion type polymer resin include: ] Solyvinyl acetate;
PVC/vinyl acetate copolymer, polyurethane, polyacrylic acid ester, styrene/butadiene/acrylic copolymer,
Polyester, etc. can be mentioned.

Various conventionally known thermofusible substances can be employed as the thermofusible substance, and examples thereof include the following.

Animal waxes such as beeswax and shellac wax, vegetable waxes such as carnauba wax, mineral waxes such as montan wax nato, petroleum waxes such as chisel rough in wax and microcrystalline wax, polyhydric alcohol esters of higher fatty acids, Higher amides, higher amines, condensates of fatty acids and amines, condensates of aromatic acids and amines, synthetic/ξ rough fins, chlorinated ξ rough fins, higher linear glycols, 3,4
- Synthetic waxy substances such as Epogi 7-hekisahi P dialkyl phthalate, metal salts of higher fatty acids, 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 0.2 parts by weight. Moreover, 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, a conventionally used binder can be used, and for example, the water-soluble resin shown 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 mating properties and writing properties. In this case, the filler may be, for example,
Examples include fine particles of calcium carbonate, magnesium carbonate, aluminized silica, Merck, barium sulfate, magnesium hydroxide, aluminum hydroxide, and styrene resin, fluorine resin, urea/formalin resin, and the like.

In order 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 layer-forming components in an appropriate solvent, and this coating solution is coated on a support.
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.

In order to effectively achieve the object of the present invention, a thick coat layer of 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 with light (wavelength shorter than 5oO nm),
The ultraviolet curable resin polymerizes, completely separating the developer layer and the leuco dye layer, resulting in a fixed recording material that cannot develop color even if reheated.

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 I Solution A: 3-cyclohexylamino-6-methyl 20 heavy J
jL part-7-anilinofluorane polyvinyl alcohol (10% aqueous solution) 2011 water
6 0
II The above composition is S? - Dispersion liquid (leuco dye dispersion liquid) A was prepared by dispersing in Lumil for 24 hours.

B liquid.

Bisphenol 8 6.0 parts by weight Sudearic acid amide 1, O nPolyvinyl alcohol (10% aqueous solution) s, O
n water
38, On The above composition was dispersed in a ball mill for 24 hours to prepare a dispersion liquid (developer liquid) B.

Next, polyvinyl alcohol (50'i-/m") was coated with polyvinyl alcohol (50% aqueous solution) and dried to give a concentration of 2 g/g (solid content). The above prepared solution A was coated and dried on 3F. /m
” (solid content), and then coated with a mixture of polyvinyl alcohol (5% aqueous solution) and dialkyl 3,4-epoxy-hexahydrophthalate (10% solution) and dried. /m” (solid content), and then apply an ultraviolet curable resin [Spirac T-
502, Showa Kobunshi ■] and dry it to 2 f/m”
(solid content). Further, as the top layer, Preparation Solution B was applied and dried to obtain a heat-sensitive recording material of the present invention having a solid content of 31/m' (solid content).

Example 2 Ethylene was used instead of the ultraviolet curable resin used in Example 1.
A heat-sensitive recording material of the present invention was obtained in exactly the same manner as in Example 1, except that cinnamate ester of vinyl alcohol copolymer was used.

Comparative Example 1 A comparative heat-sensitive recording material was obtained in the same manner as in Example 1, except that polyvinyl alcohol (5% aqueous solution) was used instead of the ultraviolet curable resin used in Example 1.

Comparative Example 2 Polyvinyl alcohol (5% solution) used in Example 1 and noalkyl 3,4-epoxyhexahyP phthalate (1
A heat-sensitive recording material for comparison was obtained in the same manner except that a mixed solution of 0% solution) was applied only once.

The heat-sensitive recording material obtained as described above was tested at 150°C12 using a thermal gradient tester [Newly manufactured by Toyo Seiki Seisakusho].
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 the Noazo copier "Ricopy 5M-2000J [manufactured by Ricoh]. After the light irradiation, the non-image area was reprinted under the same conditions as above and the color density was measured.The results are shown in Table 1.As is clear from the results in Table 1, the thermal recording material of the present invention It can be seen that this is a heat-sensitive recording material with high fixed image reliability.

Table-1 Print density: Macbeth RD-514 (filter W-10
6).

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

Claims (1)

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