JP2006255901A - Thermal recording material, thermal recording label and thermal magnetic recording paper - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermal recording material which can prevent a texture part from becoming discolored due to irradiation with light, and a thermal recording label using this thermal recording material and a thermal magnetic recording paper. <P>SOLUTION: The thermal recording material comprises an undercoat layer, a thermal color developing layer and an overcoat layer sequentially formed on a support. In this thermal recording material, a water-soluble or an emulsion ultraviolet absorbing resin is added to the thermal color developing layer and/or the overcoat layer. Further, in this material, a basic compound is added to at least either one of the undercoat layer, the thermal color developing layer or the overcoat layer. Also the thermal recording label using the thermal recording material and the thermal magnetic recording paper are provided. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a heat-sensitive recording material, a heat-sensitive recording label, and a heat-sensitive magnetic recording paper that hardly cause discoloration of a background portion (non-printing portion) due to light.

Conventionally, on a support such as paper, synthetic paper, or plastic film, a heat-sensitive recording layer mainly comprising a colorless or light leuco dye and a developer that develops color when contacted with the leuco dye is provided. Various recording materials have been proposed that utilize a color developing reaction between the developer and heat, pressure, or the like.
This type of heat-sensitive recording material does not require complicated processing such as development and fixing, can be recorded in a short time with a relatively simple device, generates less noise, and is low in cost. In addition to being used for copying books and documents, it is widely used as a recording material for electronic computers, facsimiles, ticket issuing machines, label printers, recorders, handy terminals, etc.
Due to such widespread use of thermal recording media, thermal recording paper has been stored for a long time in a lighted state regardless of whether it is indoors or outdoors. For example, fluorescent lamp irradiation on product display cases for display labels such as clothing, sunlight irradiation from windows, long-term irradiation of fluorescent lamps in warehouses for parts management labels, and outdoor sunlight for logistics labels There is irradiation.

When the thermal recording paper is exposed to these environments, a phenomenon occurs in which the chemicals constituting the thermal recording paper are decomposed by light to produce a colored product and become colored. Among them, the phenomenon that the leuco dye is decomposed by light, particularly ultraviolet rays, produces a colored product, and the thermal recording paper is discolored to yellow is one of the major drawbacks of the thermal recording paper.
Decomposition of leuco dyes by light is known to be a photo-oxidation reaction involving oxygen, and many improvement means have been proposed so far.
The basic idea is the following direction.
(I) Light blocking (light blocking by UV absorbers and reflectors)
(Ii) Oxygen blockage (preventing the participation of oxygen by membranes that do not allow oxygen to pass through)
(Iii) Antioxidants, etc. (suppression of photooxidation reaction of leuco dyes by antioxidants, light stabilizers, etc.)
Based on these directions, many techniques have been proposed so far to suppress discoloration of the background due to light.

For example, regarding (i) light blocking, examples of using an ultraviolet absorber include many proposals including Patent Document 1, Patent Document 2, Patent Document 3, Patent Document 4, Patent Document 5, Patent Document 6, and Patent Document 7. Has been.
Since these ultraviolet absorbers are usually present as particles in a dispersed state, for the purpose of improving the absorption efficiency, an ultraviolet absorbing resin (UVA resin) in which the ultraviolet absorber is incorporated in a polymer structure, or an ultraviolet absorbing agent. UV absorber microcapsules (UVA microcapsules) that encapsulate agents in a microcapsule in a liquid state (for example, dissolved in an organic solvent or in a liquid UV absorber) have been proposed. Technological development for increasing efficiency has been underway.

Among these, with respect to the ultraviolet absorbing resin, for example, in Patent Document 8, Patent Document 9, and Patent Document 10, it is proposed to develop a water-soluble or emulsion UVA resin in each layer of the heat-sensitive recording material. Similarly, Patent Document 11, Patent Document 12, and Patent Document 13 propose the development of UVA resin in the protective layer of the heat-sensitive recording material.
Furthermore, Patent Document 14 and Patent Document 15 propose a technique in which the surface of an inorganic pigment (filler) is coated with a UVA resin. Recently, a UVA resin characterized by the monomer species constituting the UVA resin itself and a combination technique of the UVA resin and various materials (additive, support = paper, etc.) are disclosed in Patent Document 16, It is proposed by Patent Literature 17, Patent Literature 18, Patent Literature 19, Patent Literature 20, and the like.
Similarly, in Patent Document 21, Patent Document 22, Patent Document 23, Patent Document 24, Patent Document 25, Patent Document 26, Patent Document 27, and the like, the combination with the application side on the thermal recording material side in which the UVA resin is developed. (For example, repetitive recording) has been continuously proposed. On the other hand, many proposals have been made for UVA microcapsules including Patent Document 28, Patent Document 29, Patent Document 30, Patent Document 31, Patent Document 32, Patent Document 33, Patent Document 34, Patent Document 35, and the like. .

As described above, the technology relating to UVA resin and UVA microcapsule continues to be proposed because of its high ultraviolet absorption efficiency and the effect of preventing discoloration caused by light in the non-image area (background area) of the resulting thermal recording paper. There are various problems regarding its practical development.
For example, since the UVA resin is in a resin state, it can be developed in the same manner as a resin material constituting a conventional heat-sensitive recording material. However, characteristics due to the structure of the UVA resin, additives constituting the UVA resin, etc. Since the influence on the heat-sensitive quality due to the influence of the resin greatly differs from the conventional resin material as the binder, there is a technical problem different from the ultraviolet absorption function.
On the other hand, in the UVA microcapsule, since the ultraviolet absorber contained in the capsule is reliably blocked by the capsule wall material, it is possible to eliminate the influence of the inclusion on the quality of the heat-sensitive recording material. However, the formation of a layer as a microcapsule has an effect on the color development characteristics such as loss of energy given from the thermal head, and has a problem in development.
In addition to blocking ultraviolet light by ultraviolet absorbers, there are other ways to prevent discoloration of heat-sensitive recording materials due to light, and (ii) for blocking oxygen, by using swellable mica, Techniques for reducing the oxygen transmission rate are proposed in Patent Document 36, Patent Document 37, Patent Document 38, Patent Document 39, Patent Document 40, Patent Document 41, and the like. Further, Patent Document 42 proposes to control oxygen permeability as a resin layer.

Furthermore, regarding the antioxidants and light stabilizers in (iii), it has been proposed that a great number of materials including hindered amines and hindered phenols are used for heat-sensitive recording materials. be able to. Patent Literature 43, Patent Literature 44, Patent Literature 45, Patent Literature 46, Patent Literature 47, Patent Literature 48, Patent Literature 49, Patent Literature 50, Patent Literature 51, Patent Literature 52, Patent Literature 53, Patent Literature 54, Patent Literature 55, Patent Literature 56, Patent Literature 57, Patent Literature 58, Patent Literature 59, and so on. Moreover, the high molecular compound containing antioxidant similarly to a ultraviolet absorber is proposed, and patent document 60, patent document 61, patent document 62, etc. exist.
However, in the function of preventing discoloration of the non-image portion (background portion) due to light, the effect when the ultraviolet absorber is present in a resin state or a microcapsule state is the greatest, and is a disadvantage of the thermal recording paper. This is a very effective technique in terms of improving the discoloration of the image portion (background portion) due to light.
Therefore, as a result of studying the technology for developing UVA resin and UVA microcapsules in heat-sensitive recording materials, we selected the development of UVA resin as a practical technology, and there were problems in the development of heat-sensitive recording materials. As a result of technological development to control discoloration (color development) caused by factors other than light in the non-image area (background part), the following technique has been obtained.

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  An object of the present invention is to provide a thermosensitive recording material capable of preventing discoloration of the background due to light irradiation, and a thermosensitive recording label, thermosensitive magnetic recording paper or thermosensitive recording film using the same.

本発明の第５は、塩基性化合物として炭酸カルシウムとヒンダードアミン化合物の両者を含有することを特徴とする請求項１記載の感熱記録材料に関する。
本発明の第６は、感熱発色層中に含まれるロイコ染料が、３−Ｎ−エチル−Ｎ−ｐ−トリル−６−メチル−７−アニリノフルオランであることを特徴とする請求項１〜５のいずれかに記載の感熱記録材料に関する。
本発明の第７は、感熱記録材料の支持体が合成樹脂フィルムであることを特徴とする感熱記録材料に関する。
本発明の第８は、請求項１〜７のいずれかに記載の感熱記録材料の裏面に粘着剤を塗布し剥離紙を貼り合わせたことを特徴とする感熱記録ラベルに関する。
本発明の第９は、請求項１〜７のいずれかに記載の感熱記録材料の裏面に加熱によって粘着性を発現する感熱粘着層を設けたことを特徴とする剥離紙を必要としない感熱記録ラベルに関する。
本発明の第１０は、請求項１〜７のいずれかに記載の感熱記録材料のオーバーコート層上にシリコーン樹脂層を設けることを特徴とする剥離紙を必要としない感熱記録ラベルに関する。
本発明の第１１は、請求項１〜７のいずれかに記載の感熱記録材料の裏面にバックコート層を設けることを特徴とする感熱記録ラベルに関する。
本発明の第１２は、請求項１〜７のいずれかに記載の感熱記録材料の裏面に磁気記録層を設けた感熱磁気記録紙に関する。 A first aspect of the present invention is a heat-sensitive recording material in which an undercoat layer, a heat-sensitive color developing layer, and an overcoat layer are sequentially provided on a support, and the heat-sensitive color developing layer and / or the overcoat layer has a water-soluble or emulsion ultraviolet ray. The present invention relates to a heat-sensitive recording material comprising an absorbent resin, and further comprising a basic compound in at least one of an undercoat layer, a heat-sensitive color-developing layer, and an overcoat layer.
The second of the present invention relates to the heat-sensitive recording material according to claim 1, wherein the basic compound is calcium carbonate.
A third aspect of the present invention relates to the heat-sensitive recording material according to claim 1, wherein the basic compound is a hindered amine compound.
According to a fourth aspect of the present invention, the hindered amine compound comprises tetrakis (1,2,2,6,6-pentamethyl-4-piperidyl) -1,2,3,4-butanetetracarboxylate (compound 1), tetrakis (2 , 2,6,6-tetramethyl-4-piperidyl) -1,2,3,4-butanetetracarboxylate (compound 2), the compound of the following structural formula (1) (compound 3) and the following structural formula (2) The heat-sensitive recording material according to claim 3, wherein at least one compound (compound 4) is contained.

A fifth aspect of the present invention relates to the heat-sensitive recording material according to claim 1, which contains both calcium carbonate and a hindered amine compound as basic compounds.
According to a sixth aspect of the present invention, the leuco dye contained in the thermosensitive coloring layer is 3-N-ethyl-Np-tolyl-6-methyl-7-anilinofluorane. To the heat-sensitive recording material according to any one of?
The seventh of the present invention relates to a heat-sensitive recording material, wherein the support of the heat-sensitive recording material is a synthetic resin film.
An eighth aspect of the present invention relates to a heat-sensitive recording label characterized in that an adhesive is applied to the back surface of the heat-sensitive recording material according to any one of claims 1 to 7 and a release paper is bonded.
According to a ninth aspect of the present invention, there is provided a thermal recording which does not require a release paper, wherein the thermal recording material according to any one of claims 1 to 7 is provided with a thermal adhesive layer that exhibits adhesiveness upon heating. Regarding labels.
A tenth aspect of the present invention relates to a thermal recording label that does not require a release paper, wherein a silicone resin layer is provided on the overcoat layer of the thermal recording material according to any one of claims 1 to 7.
The eleventh aspect of the present invention relates to a thermosensitive recording label characterized in that a backcoat layer is provided on the back surface of the thermosensitive recording material according to any one of claims 1 to 7.
A twelfth aspect of the present invention relates to a thermosensitive magnetic recording paper in which a magnetic recording layer is provided on the back surface of the thermosensitive recording material according to any one of claims 1 to 7.

The water-soluble or emulsion-type UV-absorbing resin (UVA resin) used in the present invention is a compound that contains a compound having a UV-absorbing property (UVA) in a polymer structure to be water-soluble or hydrophobic. Is an emulsion processed, and there is no particular limitation on the monomer species constituting the resin and the UVA structure contained in the resin. In this case, the UVA structure part includes ultraviolet rays such as benzotriazole ultraviolet absorbers, benzophenone ultraviolet absorbers, salicylic acid ultraviolet absorbers, cyanoacrylate ultraviolet absorbers, and triazine ultraviolet absorbers having the following ultraviolet absorptivity. Examples of the absorber and those below the multimeric compound such as a dimer and a trimer of these ultraviolet absorbers can be given. In particular,
Salicylic acid-based ultraviolet absorbers such as phenyl salicylate, p-tert-butylphenyl salicylate, and p-octylphenyl salicylate.
2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone, 2-hydroxy-4-dodecyloxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, 2- Benzophenone ultraviolet absorbers such as hydroxy-4-methoxy-5-sulfobenzophenone and bis (2-methoxy-4-hydroxy-5-benzoylphenyl) methane.
2- (2'-hydroxy-5'-methylphenyl) benzotriazole, 2- (2'-hydroxy-5'-tert-butylphenyl) benzotriazole, 2- (2'-hydroxy-3 ', 5'- Di-tert-butylphenyl) benzotriazole, 2- (2-hydroxy-3'-tert-butyl-5'-methylphenyl) -5-chlorobenzotriazole, 2- (2'-hydroxy-3 ', 5'- Di-tert-butylphenyl) -5-chlorobenzotriazole, 2- (2'-hydroxy-3,5'-di-tert-amylphenyl) benzotriazole, 2- [2'-hydroxy-3 '-(3 ″, 4 ″, 5 ″, 6 ″ -tetrahydrophthalimidomethyl) -5′-methylphenyl] benzotriazole, 2,2-methylenebis [4- 1,1,3,3-tetramethylbutyl) -6- (2H-benzotriazol-2-yl) phenol], 2 (2'-hydroxy-5'-methacryloxyphenyl) -2H-benzotriazole, etc. Benzotriazole UV absorber.
And cyanoacrylate-based ultraviolet absorbers such as 2-ethylhexyl-2-cyano-3,3′-diphenylacrylate and ethyl-2-cyano-3,3′-diphenylacrylate.

（上記一般式（５）及び（６）中、Ｒ_１は水素原子又はメチル基、Ｒ_２は直接結合又はメチレン基、Ａは直接結合、エーテル結合、エステル結合、アミド結合、ウレタン結合、Ｒ_３は直接結合又は炭素原子数１から１０のアルキレン基、Ｒ_４およびＲ_５は水素原子、ハロゲン原子、炭素数１〜１８のアルキル基、アルコキシ基を示す。） However, when obtaining the UVA resin used in the present invention, it is usually easy to produce the UVA resin by polymerizing using a monomer having a UVA structure. Therefore, it is desirable to use the following UVA monomer species, and examples of such UVA monomers include structures represented by the following general formulas (5) and (6) as general compounds.

(In the general formulas (5) and (6), R ₁ is a hydrogen atom or a methyl group, R ₂ is a direct bond or a methylene group, A is a direct bond, an ether bond, an ester bond, an amide bond, a urethane bond, R _3. Represents a direct bond or an alkylene group having 1 to 10 carbon atoms, R ₄ and R ₅ represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 18 carbon atoms, or an alkoxy group.)

本発明においては、このようなＵＶＡモノマーを他の重合性モノマーと重合させることでアクリル系、アクリルウレタン系をはじめとするＵＶＡ樹脂を生成することができる。
本発明においては、これらのＵＶＡ樹脂を水溶化又は、エマルジョン化することで感熱記録材料に展開可能なＵＶＡ樹脂とすることができる。
この場合、エマルジョン化においては各種乳化剤の存在下で乳化することができるが、水溶化する場合には、例えばアクリル酸モノマーをＵＶＡ樹脂を重合する際のモノマー成分として存在させ、更に、アクリル酸部位を例えばアンモニウムやアミン類等の塩基性物質で中和して塩化することで水溶性状態を実現することができる。 Further, with respect to these general formulas (5) and (6), from the relationship of safety of the UVA structure part, the description of the general formula (5) having a 2- (2′-hydroxyphenyl) benzotriazole structure A compound is preferred, and a specific example thereof is a UVA monomer (trade name = Otsuka Chemical RUVA-93) represented by the following chemical formula (7).

In the present invention, such UVA monomers can be polymerized with other polymerizable monomers to produce UVA resins including acrylics and acrylic urethanes.
In the present invention, these UVA resins can be made into UVA resins that can be developed on heat-sensitive recording materials by making them water-soluble or emulsifying.
In this case, the emulsion can be emulsified in the presence of various emulsifiers, but when water-solubilized, for example, an acrylic acid monomer is present as a monomer component when polymerizing the UVA resin, and the acrylic acid moiety A water-soluble state can be realized by neutralizing and chlorinating with a basic substance such as ammonium or amines.

However, since the UVA resin produced in this way has a phenolic OH group in its molecular structure, when these are used in a thermal recording material in the resin state, the leuco dye contained in the coloring layer is colored. As a result, the stability of the non-image part (background part) is lowered.
This tendency becomes prominent particularly under conditions where heat and / or humidity is applied, and becomes a big problem when realizing prevention of coloring of non-image areas by light with UVA resin.
In addition, since it exists as a resin containing such a UVA structure, the influence on the color development of the non-image area is greater than when a conventional UVA compound is used in the form of dispersed particles. This is in contradiction to obtaining an excellent effect for preventing discoloration due to light.
Although it is possible to remove the structure (phenolic OH) that has the property of causing the leuco dye to develop color in such UVA resin, the UV absorbing function in which benzotriazole and benzophenone UV absorbers are stable and excellent Since this phenolic OH group is involved in developing the function, the elimination of the phenolic OH group significantly reduces the function as a UV absorber and prevents discoloration due to light. It is a direction that deviates from the purpose.

これらの有機化合物の中では、ヒンダードアミン系化合物は、塩基性物質として熱や湿度に対する非画像部の発色を抑えるとともに、感熱発色層に対する発色阻害もなく優れた特性を発現することができる。更に、これらのヒンダードアミン系化合物は、光安定剤としての機能を持ち合わせていることから、光による非画像部の変色にたいしてもＵＶＡ樹脂と相乗効果を発現することができ、非画像の各種環境下における信頼性を著しく向上させることができる。これらの中でも特に化合物（１）〜（４）の化合物がよりいっそう好ましい。 On the other hand, preventing the leuco dye in the thermosensitive coloring layer from contacting the UVA resin is one of the methods for preventing the coloration of the leuco dye due to heat and humidity. In this case, however, the layer structure is complicated. And isolation measures such as microencapsulation of leuco dyes are taken, and the obstacles in producing a heat-sensitive recording material are large and unrealistic. In addition, since the color forming material is processed for isolation, it cannot be said that it is an effective means because it is accompanied by a decrease in the color forming characteristics.
In this situation, when the UVA resin is used effectively in this situation, the present invention effectively uses a basic substance for the problem that the leuco dye in the thermosensitive coloring layer is colored by heat and humidity. In addition, both the prevention of discoloration due to light by the UVA resin and the coloring property are achieved.
As the basic substance used in the present invention, an inorganic compound or a basic substance as an organic compound can be used. As the basic substance as an inorganic compound, calcium carbonate, magnesium carbonate, zinc carbonate, or the like can be given. However, among them, calcium carbonate is excellent. On the other hand, examples of the basic compound as the organic compound include the following compounds which are amine compounds.
Primary amine compounds such as butylamine, isobutylamine, ethylaminoethylamine, diethylaminoethylamine, 1,2-diaminopropane, 1,3-diaminopropane and dimethylaminopropylamine. Secondary amine compounds such as piperidine, 3-pipecoline, 4-pipecoline, 2,4-lutidine, 2,6-lutidine and 3,5-lutidine. Although these primary amines and secondary amines exist in a liquid state, they can be added by being retained in the coating component of the heat-sensitive recording material in a state of being soaked in the coating component.
Furthermore, N, N, N ′, N′-tetramethyl-1,2-diaminoethane, triphenylamine derivatives (eg: Adeka Cruz TPA series), pyrazole derivatives (eg: Adeka Cruz PZ series),
Tetrakis (1,2,2,6,6-pentamethyl-4-piperidyl) -1,2,3,4-butanetetracarboxylate (Compound 1) (Adeka Stub LA-52, Adeka Arch Cruise DN-44M),
Tetrakis (2,2,6,6-tetramethyl-4-piperidyl) -1,2,3,4-butanetetracarboxylate (compound 2) (ADK STAB LA-57),
The compound of the structural formula (1) (compound 3) (ADK STAB LA-63P),
Compound of the structural formula (2) (Compound 4) (ADK STAB LA-68LD),
A compound of the following structural formula (8) (ADK STAB LA-77),
A hindered amine compound such as a compound of the following structural formula (9) (Adekastab LA-87).
Further, in the liquid state, the compound of the following structural formula (10) (ADK STAB LA-62), which is a hindered amine compound in a liquid state having a similar structure to the above (compound 1) and (compound 2), the following structural formula (11) The hindered amine compound etc. which are represented by the compound of (Adekastab LA-67) can also be mentioned.

Among these organic compounds, hindered amine compounds as basic substances can suppress the color development of the non-image area with respect to heat and humidity, and can exhibit excellent characteristics without color development inhibition with respect to the heat-sensitive color development layer. Furthermore, since these hindered amine compounds have a function as a light stabilizer, they can exhibit a synergistic effect with the UVA resin for discoloration of the non-image area due to light, and under various non-image environments. Reliability can be significantly improved. Of these, the compounds (1) to (4) are particularly preferred.

The heat-sensitive recording material of the present invention is constituted by appropriately using various chemical substances other than the UVA resin and the basic substance, and specific examples thereof are listed below.
Specific examples of the water-soluble resin used for the protective layer (overcoat layer) in the present invention include the following, but the present invention is not limited thereto.
Polyvinyl alcohol, modified polyvinyl alcohol, starch and derivatives thereof, cellulose derivatives such as methoxycellulose, hydroxyethylcellulose, carboxymethylcellulose, methylcellulose, ethylcellulose, polyacrylic acid soda, polyvinylpyrrolidone, acrylamide / acrylic acid ester copolymer, acrylamide / acrylic acid Ester / methacrylic acid terpolymer, styrene / maleic anhydride copolymer antkari salt, isobutylene / maleic anhydride copolymer antkari salt, polyacrylamide, modified polyacrylamide, methyl vinyl ether-maleic anhydride copolymer, Carboxy-modified polyethylene, polyvinyl alcohol / acrylamide block copolymer, melamine-formaldehyde resin, urea-formalde De resins, sodium alginate, gelatin, water-soluble polymer such as casein. Among these, polyvinyl alcohol is excellent, and among them, diacetone-modified polyvinyl alcohol is excellent.
Next, although the specific example of the crosslinking agent which can react with the said water-soluble resin is shown, it is not limited to these about a crosslinking agent.
The crosslinking agent (curing agent) in this case may be any one that can reduce the solubility of the water-soluble resin in water by reacting with the water-soluble resin. For example, a glyoxal derivative, a methylol derivative , Epichlorohydrin derivatives, epoxy compounds, aziridine compounds, hydrazine and hydrazide derivatives.

In addition, the thermosensitive coloring layer in the present invention has a function of developing color by heat. As an example of the coloring system, a coloring reaction between a basic dye precursor (leuco dye) and an acidic substance (developer) is performed. Can be mentioned. In this case, the basic dye precursors (leuco dyes) used can be used alone or in combination of two or more. As such leuco dyes, those applied to heat-sensitive materials are arbitrarily used. For example, the following can be mentioned.
3,3-bis (P-dimethylaminophenyl) phthalide, 3,3-bis (P-dimethylaminophenyl) -6-dimethylaminophthalide, 3-diethylamino-6-methyl-7-anilinofluorane, 3 -Dibutylamino-6-methyl-7-anilinofluorane, 3-N-methyl-N-butylamino-6-methyl-7-anilinofluorane, 3-N-ethyl-Np-tolyl-6 -Methyl-7-anilinofluorane, 3-N-methyl-N-propylamino-6-methyl-7-anilinofluorane, 3-N-ethyl-N-propylamino-6-methyl-7-ani Linofluorane, 3-N-methyl-N-amylamino-6-methyl-7-anilinofluorane, 3-N-ethyl-N-amylamino-6-methyl-7-anilinofluorane, 3-N- Tyl-N-isoamylamino-6-methyl-7-anilinofluorane, 3-N-hexyl-N-isoamylamino-6-methyl-7-anilinofluorane, 3-N-methyl-N-cyclohexylamino -6-methyl-7-anilinofluorane, 3-N-ethyl-N-furanylmethylamino-6-methyl-7-anilinofluorane, 3-diethyl-N-butylamino-7- (2 ' -Fluoroanilino) fluorane, 3-pyrrolidyl-7-dibenzylaminofluorane, 3-bis (diphenylamino) fluorane, 3-diethylamino-7- (2'-chloroanilino) fluorane, 3-diethylamino-6-chloro- 7-anilinofluorane, 3-dibutylamino-7- (2'-chloroanilino) fluorane, 3-diethylamino-7-chloro Luolan, 3-diethylamino-6-methyl-7-chlorofluorane, 3-N-methyl-N-cyclohexylamino-6-chlorofluorane, 3-diethylamino-6-methyl-7- (2 ', 4'- Dimethylanilino) fluorane, 3-diethylamino-7-dibenzylaminofluorane, 3-butylamino-7- (2'-chloroanilino) fluorane, 3-diethylamino-6-ethoxyethyl-7-anilinofluorane and the like.
Among these, 3-N-ethyl-Np-tolyl-6-methyl-7-anilinofluorane itself is less likely to be colored by light, and is also less likely to be colored by heat or light. Therefore, it is excellent in that a very high function can be expressed by developing the technique of the present invention.

Moreover, the following can be mentioned as a developer compound which colors the said leuco dye.
4,4'-isopropylidenebisphenol, 4,4'-isopropylidenebis (o-methylphenol), 4,4'-butylidenebisphenol, 4,4'-isopropylidenebis (2-butylphenol), p-nitro Zinc benzoate, 1,3,5-tris (4-butyl-3-hydroxy-2,6-dimethylbenzyl) isocyanuric acid, 2,2- (3,4-dihydroxyphenylpropane), bis (4-hydroxy- 3-methylphenyl sulfide), 4- [β- (p-methoxyphenoxy) ethoxy] salicylic acid, 1,7-bis (4-hydroxyphenylthio) -3,5-dioxaheptane, phthalic acid monobenzyl ester monocarboxylic acid Acid, 4,4'-cyclohexylidenebisphenol, 4,4'-isopropylidenebis (2-chloro Enol), 2,2'-methylenebis (4-methyl-6-butylphenol), 4,4'-butylidenebis (6-butyl-2-methyl) phenol, 1,1,3-tris (2-methyl-4- Hydroxy-5-cyclohexyl) butane, 4,4'-thiobis (6-butyl 2-methylphenol) 4,4'-dihydroxydiphenyl sulfone, 4-benzyloxy-4'-hydroxydiphenyl sulfone, 4-isopropyloxy-4 '-Hydroxydiphenylsulfone, 4,4'-diphenol sulfoxide, isopropyl p-hydroxybenzoate, benzyl p-hydroxybenzoate, benzyl protocatechuate, stearyl gallate, 1,3-bis (4-hydroxyphenylthio)- Propane, 1,3-bis (4-hydroxyphenylthio) 2-hydroxypropane, N, N-diphenylthiourea, N, N-di (m-chlorophenylthiourea), salicylanilide, 5-chlorosalicylanilide, bis (4-hydroxyphenyl) acetic acid methyl ester, bis (4 -Hydroxyphenyl) acetic acid benzyl ester, 1,3-bis (4-hydroxycumyl) benzene, 1,4-bis (4-hydroxycumyl) benzene, 2,4'-dihydroxydiphenylsulfone, 2,2'- Diallyl-4,4′-diphenolsulfone, 3,4-dihydroxy-4′-methyldiphenylsulfone, α, α-bis (4-hydroxyphenyl) -α-methyltoluene, 4,4′-thiobis (2- Methylphenol), 4,4'-thiobis (2-chlorophenol) and the like.
Furthermore, examples include oligomer-type color developers obtained by polymerizing 4,4′-dihydroxydiphenylsulfone via a linking group such as an ether bond, and various oligomer-type compounds.
Further, the ratio of the leuco dye to the developer in the thermosensitive coloring layer is preferably 0.5 to 10 parts, preferably 1 to 5 parts (all parts are by weight).

In the thermosensitive coloring layer, a sensitivity improver and various thermofusible substances can be used alone or in combination of two or more.
Specific examples thereof include the following.
Fatty acids such as stearic acid and behenic acid, stearic acid amide, erucic acid amide, palmitic acid amide, behenic acid amide, fatty acid amides such as palmitic acid amide, N-lauryl lauric acid amide, N-stearyl stearic acid amide, N N-substituted amides such as oleyl stearic acid amide, bis fatty acid amides such as methylene bis stearic acid amide, ethylene bis stearic acid amide, ethylene bis lauric acid amide, ethylene bis capric acid amide, ethylene bis behenic acid amide, hydroxy Hydroxy fatty acid amides such as stearic acid amide, methylene bishydroxystearic acid amide, ethylene bishydroxystearic acid amide, hexamethylene bishydroxystearic acid amide, zinc stearate, aluminum stearate Fatty acid metal salts such as calcium stearate, zinc palmitate, zinc behenate, p-benzylbiphenyl, terphenyl, triphenylmethane, benzyl p-benzyloxybenzoate, β-benzyloxynaphthalene, phenyl β-naphthoate, -Phenyl hydroxy-2-naphthoate, methyl 1-hydroxy-2-naphthoate, diphenyl carbonate, benzyl terephthalate, 1,4-dimethoxynaphthalene, 1,4-diethoxynaphthalene, 1,4-dibenzyloxynaphthalene, 1,2-diphenoxyethane, 1,2-bis (4-methylphenoxyethane), 1,4-diphenoxy-2-butene, 1,2-bis (4-methoxyphenylthio) ethane, dibenzoylmethane, 1 , 4-Diphenylthiobutane, 1,4-diphenyl O-2-butene, 1,3-bis (2-vinyloxyethoxy) benzene, 1,4-bis (2-vinyloxyethoxy) benzene, p- (2-vinyloxyethoxy) biphenyl, p-aryloxybiphenyl , Dibenzoyloxymethane, dibenzoyloxypropane, dibenzyl disulfide, 1,1-diphenylethanol, 1,1-diphenylpropanol, p-benzyloxybenzyl alcohol, 1,3-phenoxy-2-propanol, N-octadecylcarbamoyl -P-methoxycarbonylbenzene, N-octadecylcarbamoylbenzene, 1,2-bis (4-methoxyphenoxy) propane, 1,5-bis (4-methoxyphenoxy) -3-oxapentane, dibenzyl oxalate, bis (oxalate) ( 4-methylbenzyl , Oxalic acid bis (4-chlorobenzyl) or the like.

In preparing the heat-sensitive recording material of the present invention, various materials conventionally used for constituting a heat-sensitive recording material are appropriately used in addition to the developer, leuco dye, and heat fusible substance. Can do.
Examples thereof include, for example, binders for binding various materials on a support or the like in a heat-sensitive recording layer, and these can be used alone or in combination of two or more. Include the following:
Polyvinyl alcohol, modified polyvinyl alcohol, starch and derivatives thereof, cellulose derivatives such as methoxycellulose, hydroxyethylcellulose, carboxymethylcellulose, methylcellulose, ethylcellulose, polyacrylic acid soda, polyvinylpyrrolidone, acrylamide / acrylic acid ester copolymer, acrylamide / acrylic acid Ester / methacrylic acid terpolymer, styrene / maleic anhydride copolymer antkari salt, isobutylene / maleic anhydride copolymer antkari salt, polyacrylamide, modified polyacrylamide, methyl vinyl ether-maleic anhydride copolymer, Carboxy-modified polyethylene, polyvinyl alcohol / acrylamide block copolymer, melamine-formaldehyde resin, urea-formalde De resins, sodium alginate, gelatin, water-soluble polymer such as casein. Polyvinyl acetate, polyurethane, styrene / butadiene copolymer, styrene / butadiene / acrylic copolymer, polyacrylic acid, polyacrylic acid ester, polymethacrylic acid ester, vinyl chloride / vinyl acetate copolymer, polybutyl methacrylate, Examples thereof include emulsions such as polyvinyl butyral, polyvinyl acetal, and ethylene / vinyl acetate copolymer.
These may be used alone or in combination, and may be further cured by adding a crosslinking agent (curing agent) as necessary.
In this case, the crosslinking agent (curing agent) reacts with the binder, and examples thereof include a glyoxal derivative, a methylol derivative, an epichlorohydrin derivative, an epoxy compound, and an aziridine compound.

Specific examples of the pigment used alone or in combination of two or more in the heat-sensitive recording material include the following.
Silica, zinc oxide, titanium oxide, aluminum hydroxide, zinc hydroxide, barium sulfate, clay, kaolin, calcined kaolin, talc, surface-treated silica and other inorganic fine powders, urea-formalin resin, styrene / methacrylic acid Examples include organic fine powders such as copolymers, polystyrene resins, vinylidene chloride resins, styrene / acrylic copolymers, and plastic spherical hollow fine particles.
Furthermore, in the protective layer of the heat-sensitive recording material of the present invention, pigments other than the resin and crosslinking agent, and lubricants (thermofusible substances) can be used, and for these, the pigments, binders and crosslinking agents described above are used. The lubricant (heat fusible substance) can be used alone or in combination of two or more.

In addition, an intermediate layer is provided between the support and the thermosensitive coloring layer. In this case, as the pigment and binder constituting the intermediate layer, each of the above pigments and binders is used alone or in combination of two or more. Can be used.
The thermoplastic hollow resin particles which are an example of the pigment in this case are, for example, spherical hollow fine particles which are made of a thermoplastic polymer as a shell and contain air or other gas inside and are already in a foamed state. .
The hollow ratio of the thermoplastic hollow resin particles is a ratio of the outer diameter to the inner diameter of the hollow particles and is represented by the following formula.
Hollow ratio (hollowness) (%) = (inner diameter of hollow particles / outer diameter of hollow particles) × 100
Plastic spherical hollow fine particles are acrylic resins such as acrylate and acrylonitrile, styrene resins such as styrene or copolymer resins thereof, acrylonitrile and / or methacrylonitrile and / or acrylate and / or methacrylate. It can be made from a polymer, a copolymer comprising a vinyl monomer having two or more vinyl groups per molecule and / or a monomer containing divinylbenzene.

Furthermore, in the heat-sensitive recording material of the present invention, it is also possible to provide a back layer mainly composed of a pigment, a resin, a crosslinking agent and the like on the back surface of the support.
In this case, the pigment, binder, and lubricant (heat fusible substance) are used as the pigment, binder, and lubricant.
In addition to normal paper (acidic paper, neutral paper), any material that can be applied and processed can be arbitrarily used as the support, and examples thereof include synthetic paper and polymer films.
In obtaining the heat-sensitive recording material of the present invention, in addition to the above, additive components commonly used in this type of heat-sensitive recording material, for example, a surfactant, a pressure coloring agent, and the like can be used in combination.

  ADVANTAGE OF THE INVENTION According to this invention, the thermosensitive recording material which can prevent the discoloration of the background part by light irradiation, and the thermosensitive recording label, thermosensitive magnetic recording paper, or thermosensitive recording film using the same could be provided.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention further in detail, this invention is not limited at all by these Examples.

<Preparation of Samples for Examples and Comparative Examples>
Adjustment of coating liquid for each layer (thermosensitive coloring layer, intermediate layer, protective layer) Adjustment of undercoat layer coating liquid (U liquid) Next, a mixture of the following composition was mixed and stirred to disperse undercoat layer coating liquid [U liquid] Adjusted.
[Liquid U] 10% solid content
Plastic spherical hollow particles (hollow rate 90%, solid content 40%) 25 parts styrene / butadiene copolymer latex (solid content concentration 47.5%) 15 parts water 131 parts Preparation of thermosensitive coloring layer coating liquid (liquid T) The liquid mixture is dispersed by a magnetic ball mill to prepare [A liquid] to [C liquid].
[Liquid A] = leuco dye dispersion 10 leuco dyes listed in Table 1 10 parts 10% polyvinyl alcohol aqueous solution 10 parts water 30 parts [Liquid B] = developer dispersion 4-hydroxy-4'-isopropoxydiphenyl sulfone 10 Part 10% polyvinyl alcohol aqueous solution 10 parts water 30 parts [liquid C] = pigment dispersion silicon dioxide powder 10 parts 10% polyvinyl alcohol aqueous solution 10 parts water 30 parts [liquid T] solid content 10%
Liquid A: Liquid B: Liquid C: Water = 1: 3: 3: 7 mixture.

Adjustment of Overcoat Layer Coating Solution (O Solution) Next, a protective layer coating solution [O solution] was prepared by mixing and dispersing a mixture having the following composition.
[Liquid O] Solid content 10%
Inorganic pigment dispersion (solid content: 20%) 50 parts Zinc stearate (solid content: 10%) 10 parts Water-soluble resin (solid content: 10% aqueous solution) 100 parts Crosslinker (solid content: 10% aqueous solution) 20 parts 50 parts of water Using the coating solution prepared as described above, the undercoat layer forming solution was applied and dried on the surface of commercially available high-quality paper (basis weight 60 g / m ² ) so that the dry weight was 3 g / m ^2. Thus, a paper coated with an undercoat layer was obtained. Next, the heat-sensitive color forming layer-forming liquid was applied and dried so that the dry weight of the leuco dye was 0.5 g / m ² to obtain a paper having a heat-sensitive color layer coated. Further, an overcoat layer (protective layer) coating solution is applied and dried so that the dry weight is 3.0 g / m ² and stored in a 40 ° C. environment for 15 hours, and then a pressure of 20 kg / cm ² is applied. The heat-sensitive recording material of the present invention was obtained by calendering.
When the thermosensitive recording material of the present invention is prepared by adding a UVA resin and a basic substance based on the above basic prescription system, the following additive components (UVA resin and basic substance) are added to the basic prescription. To add. In this case, regarding the adhesion amount of the coating layer, the total adhesion amount of each layer is appropriately increased according to the amount of the additive component. Table 1 shows the configuration of the embodiment and comparative examples showing the effects of the present invention.

Addition of UVA component [UVA1]
WF-825 (water-soluble UVA resin) by Sannan Synthetic Chemical Co., Ltd. 30% total solids (9% UVA solids)
[UVA2]
Shinko Nakamura New Coat UVA-204W (water-based emulsion UVA resin) 20% total solids (9% UVA solids)
[UVA3] / Dispersion RUVA-93 aqueous dispersion obtained in the same manner as in the above [C liquid] (UVA monomer itself contained in UVA1 and UVA2) UVA solid content 20%
About these UVA1-UVA3, it shall apply | coat and dry after adding preparation to each layer coating liquid so that the addition amount as a UVA component may be 0.5 g / m < ² > as an adhesion amount after drying.
As for the basic substance added to the basic component, the basic substance shown in Table 1 is added to the coating liquid of each layer to be added in the same manner as the UVA component.
In this case, the addition amount is to be applied and dried in each layer coating solution after addition and preparation so that the adhesion amount after drying as a basic substance is 0.5 g / m ² . The basic substance dispersion was prepared in the same manner as in the above [C liquid].

添加層：ＯＣ（オーバーコート層）、ＴＣ（感熱発色層）、ＵＣ（アンダーコート層）
Ｄｙｅ１：３−ジブチルアミノ−６−メチル−７−アニリノフルオラン
Ｄｙｅ２：３−Ｎ−エチル−Ｎ−ｐ−トリル−６−メチル−７−アニリノフルオラン

Additional layer: OC (overcoat layer), TC (thermosensitive coloring layer), UC (undercoat layer)
Dye1: 3-dibutylamino-6-methyl-7-anilinofluorane Dye2: 3-N-ethyl-Np-tolyl-6-methyl-7-anilinofluorane

The following items were evaluated for the samples of Examples and Comparative Examples shown in Table-1.
(Color density)
Using a thermal inclination tester, printing with a heat block (2 kgf / cm ² 1 second) was performed in increments of 10 ° C. in a temperature range of 200 to 110 ° C., and the maximum color density was measured with a Macbeth reflection densitometer.
(Non-image area heat resistance)
The test piece was stored in a constant temperature and humidity chamber at 80 ° C. (DRY) for 15 hours, and the density of the non-image area after storage was measured with a Macbeth reflection densitometer. However, Examples 18 and 19 and Comparative Example 8 were tested at a temperature condition of 90 ° C.
(Non-image area moisture resistance)
The test piece was stored in a constant temperature and humidity chamber at 40 ° C.-90% RH for 15 hours, and the density of the non-image area after storage was measured with a Macbeth reflection densitometer.
(Non-image area light resistance)
Using a weatherometer made by Toyo Seiki, the color value of the non-image area after irradiating the test piece with xenon light for 12 hours was measured with a spectrocolorimeter CM-3700d manufactured by Minolta, and the b * value was obtained. .
The evaluation results are shown in Table 2 below.

表２の結果より、本発明の感熱記録材料は非画像部（地肌部）の耐光性をＵＶＡ樹脂の展開によって改善するとともに、この際に問題となる非画像部の熱や湿度による発色の発生を大幅に改善したものである。

From the results shown in Table 2, the heat-sensitive recording material of the present invention improves the light fastness of the non-image area (background area) by developing the UVA resin, and the non-image area develops color development due to heat and humidity, which is a problem at this time. Is a significant improvement.

Claims (12)

  In the thermosensitive recording material in which an undercoat layer, a thermosensitive coloring layer, and an overcoat layer are sequentially provided on a support, the thermosensitive coloring layer and / or the overcoat layer contains a water-soluble or emulsion ultraviolet absorbing resin, The thermosensitive recording material further comprises a basic compound in at least one of an undercoat layer, a thermosensitive coloring layer, and an overcoat layer.   2. The heat-sensitive recording material according to claim 1, wherein the basic compound is calcium carbonate.   The heat-sensitive recording material according to claim 1, wherein the basic compound is a hindered amine compound. The hindered amine compound is tetrakis (1,2,2,6,6-pentamethyl-4-piperidyl) -1,2,3,4-butanetetracarboxylate (compound 1), tetrakis (2,2,6,6- Tetramethyl-4-piperidyl) -1,2,3,4-butanetetracarboxylate (compound 2), compound of the following structural formula (1) (compound 3) and compound of the following structural formula (2) (compound 4) The heat-sensitive recording material according to claim 3, comprising at least one of the following.

  2. The heat-sensitive recording material according to claim 1, comprising both calcium carbonate and a hindered amine compound as a basic compound.   6. The leuco dye contained in the heat-sensitive coloring layer is 3-N-ethyl-Np-tolyl-6-methyl-7-anilinofluorane. Thermal recording material.   A heat-sensitive recording material, wherein the support of the heat-sensitive recording material is a synthetic resin film.   A heat-sensitive recording label, wherein a pressure-sensitive adhesive is applied to the back surface of the heat-sensitive recording material according to any one of claims 1 to 7, and a release paper is bonded thereto.   A heat-sensitive recording label that does not require a release paper, wherein a heat-sensitive adhesive layer that exhibits adhesiveness by heating is provided on the back surface of the heat-sensitive recording material according to claim 1.   A thermal recording label that does not require a release paper, wherein a silicone resin layer is provided on the overcoat layer of the thermal recording material according to claim 1.   A thermosensitive recording label comprising a backcoat layer on the back surface of the thermosensitive recording material according to claim 1. A heat-sensitive magnetic recording paper comprising a magnetic recording layer provided on the back surface of the heat-sensitive recording material according to claim 1.