JP5664155B2 - Thermosensitive adhesive material and thermosensitive adhesive sheet using the thermosensitive adhesive material - Google Patents

Description

  The present invention relates to a pressure-sensitive adhesive material suitable for a label to be attached to the surface of a packaging member such as fresh vegetables and daily foods or apparel. In particular, the present invention is non-adhesive at normal temperature, but can exhibit adhesiveness by applying heat, and when peeled off, the label side residue (coating layer transfer, label residue) is left on the adherend surface. The present invention relates to a heat-sensitive adhesive material suitable for repeated use of an adherend and a heat-sensitive adhesive sheet using the heat-sensitive adhesive material.

A heat-sensitive adhesive material does not exhibit adhesiveness at room temperature but develops adhesiveness when heated by a heat source. Unlike general pressure-sensitive adhesive materials, a release paper is not required. (1) No need to dispose of it. (2) Since the thickness of the release paper is reduced, the roll length per roll can be increased and it is suitable for transportation. Collecting.
As a general composition of this heat-sensitive adhesive material, a thermoplastic resin and a solid plasticizer (hot-melting substance) are the main components, and a tackifier is contained as necessary (Non-patent Document 1). The thermoplastic resin in the present invention imparts tackiness and adhesiveness, while the solid plasticizer (hot meltable substance) is a solid at room temperature but melts by heating to form a thermoplastic resin. It is swollen or softened to develop adhesiveness. Moreover, a tackifier is added in order to improve and adjust adhesiveness. The present invention does not exhibit any tackiness at room temperature by combining such components, but it develops tackiness by heating and can maintain tackiness for a while even after the heat source is removed. It is. Various methods for activating the heat-sensitive adhesive material have been proposed.

For example, a method using an electric heater or a dielectric coil (Patent Document 1), a method using a xenon flash (Patent Document 2), and a method using a halogen lamp (Patent Document 3) are described. It is difficult to efficiently apply heat to the heat-sensitive adhesive layer, and not only the heat energy is not used effectively, but this is not only a cause of high energy costs, but also the size of the device is large and the overall device is compact. There is a problem that the sex is impaired.
Further, a heated heat transfer medium such as a method in which a heating drum is brought into contact with a heat-sensitive adhesive layer (Patent Document 4) and a method in which a hot roll is brought into contact with a heat-sensitive adhesive layer (Patent Document 5). Prior to the filing of this application, methods for heat activation by contacting the layers have been known. However, in order to speed up the heat activation, these methods wait in a state where heat is applied to the heating means. There is a problem in terms of safety. When the recording label has a heat-sensitive color developing layer, the above heat activation method makes it easier for the heat-sensitive color developing layer to develop a color due to the heat at the time of heat activation. It must be improved, which is disadvantageous in terms of thermal sensitivity.

Another advantage of the heat-sensitive adhesive material is that it can control the part that develops the adhesiveness, and therefore imparts adhesiveness only to the necessary part. For this purpose, a heat-sensitive adhesive material is applied to a necessary portion in advance and heat is applied to the entire surface later, or a heat-sensitive adhesive material is applied to the entire surface and heat is applied to the required portion. There are two methods, but it is only the latter that can realize the on-demand adhesion area, which has been increasing in recent years.
In consideration of such various concerns, an activation means using a thermal head is suitable as a thermal activation method. The method using this thermal head is excellent in that it consumes less energy during thermal activation, can be made safer and more compact, and can selectively apply heat to necessary parts. It has characteristics (Patent Documents 6 and 7).

By the way, in recent years, from the viewpoints of environmental friendliness and recycling, there has been an increasing demand for packaging materials that can be used repeatedly for logistics packaging. For example, it does not generate waste like paper cardboard, but is typified by polypropylene containers and cardboard (pradan), or foldable placon (oricon) with good space saving when not in use. Opportunities to use returnable logistics supplies are increasing. Since these returnable logistics products are supposed to be used repeatedly, the label with the address and instructions is peeled off before the next use, and a new label is applied, or stacked as it is. Although it is pasted and used, there is a drawback that it gradually gets dirty. For example, since adhesive residue is likely to occur when peeling off, dirt accumulates, and it gradually becomes noticeable and gives an unsanitary impression, thereby deteriorating the image of the product. For this reason, it may be avoided from transporting foods such as fresh vegetables and daily foods or apparel. Also, by repeatedly using it, it is necessary to apply the newly issued label on top of the label that was used before or after the label has been peeled off, so the application surface is not clean and flat. In addition to not being able to exhibit sufficient adhesive strength, there is a problem in that dropout tends to occur.
Moreover, since the labor for peeling off is required at the same time, the efficiency of work is deteriorated.

When using a general pressure-sensitive label type label for repeated use, for example, a label using an alkali-dispersed hot-melt pressure-sensitive adhesive that can be easily peeled off when hot or weak alkaline water is applied. Although it may be used (Patent Document 8), a large amount of investment is required because the equipment for the processing becomes large.
Moreover, in such a case, since it cannot be regenerated unless it is stored in one place, there is a drawback that the amount of carbon dioxide emission due to its transportation becomes large. For example, a delayed-tack type label uses an ethylene polymer and a urethane resin in combination (Patent Document 9). However, with such a configuration, adhesive deactivation is fast and is not suitable for thermal head activity. Moreover, since heat responsiveness is low, there is also a problem that sufficient adhesive force cannot be obtained unless heat is continuously applied.
Therefore, when the present technology is applied to the back surface of the heat-sensitive recording material, there is a problem that heat spreads to the opposite surface and causes background fogging. There are also methods such as a method of providing a heat-sensitive adhesive layer on a cross-linked resin layer containing a cross-linked resin (Patent Document 10) and a method of cross-linking a resin of a thermally active layer (Patent Document 11). Neither method is sufficient.

  The present application solves many conventional problems as described above, and when peeled, there is no label side residue (coating layer transfer, label remaining) on the adherend surface, and repeated use of the adherend. And a heat-sensitive adhesive sheet using the heat-sensitive adhesive material.

That is, the present application according to the first invention, on a support, the middle air under layer, then a thermoplastic resin, a solid plasticizer, and heat-sensitive adhesive material of the heat-sensitive adhesive layer comprising a tackifier sequentially applying The present invention provides a heat-sensitive adhesive material, wherein the hollow underlayer contains hollow particles, a thermoplastic resin, and a self-crosslinking acrylic resin.
According to a second aspect of the present invention, there is provided the above heat-sensitive adhesive material, wherein the adhesiveness is manifested by heating with a thermal head.
According to a third aspect of the present invention, there is provided a heat-sensitive adhesive sheet using the above-mentioned heat-sensitive adhesive material, which has a recording layer on the side opposite to the surface having the heat-sensitive adhesive layer of the support.
According to the fourth invention, the recording layer is any one of a heat-sensitive recording layer, a heat-melt transfer recording ink-receiving layer, an electrophotographic toner image-receiving layer, a silver halide photographic recording layer, and an ink-jet ink image-receiving layer. There is provided the heat-sensitive adhesive sheet according to the third invention.
According to a fifth invention, there is provided the heat-sensitive adhesive sheet according to the third or fourth invention, wherein synthetic paper or plastic film is used as the substrate.

  By using the pressure-sensitive adhesive sheet of the present invention, it can be firmly attached to a plastic substrate such as a container, and at the same time there is almost no adhesive residue at the time of peeling, so there is no contamination of the adherend, and the adherend Can be used repeatedly.

As a result of intensive research to solve the above problems, in the heat-sensitive adhesive material obtained by laminating the hollow under layer and the heat-sensitive adhesive layer, if there is adhesive residue on the adherend, it is a cohesive failure of the hollow under layer. It has become. Therefore, it is necessary to improve the cohesive strength of the hollow underlayer. In order to improve the cohesive force, for example, it can be considered that the resin itself is in a hard direction, but even if a hard resin is simply applied, the hardness of the entire layer increases, and the head matching property deteriorates. In other words, a trouble such as a chatter noise is generated at the time of conveyance.
On the other hand, when a soft material is applied, the material is easily deformed by an external factor, so that it is weak against rust and the inside of the printer is contaminated during conveyance. Therefore, as a result of repeated studies by the present inventors, it is necessary to increase the cohesive force while maintaining the current softness, and in order to achieve this purpose, a self-crosslinking acrylic resin can be added. It has been found to be the most effective. In the case of this self-crosslinking acrylic resin, it can be handled in the same manner as a normal acrylic resin up to the point of application, and once formed into a film, it has a characteristic that a crosslinking effect is exhibited and it has an appropriate viscosity.

《Heat-sensitive adhesive material》
The heat-sensitive adhesive material in the present invention has a structure in which a hollow under layer and a heat-sensitive adhesive layer are laminated.

《Hollow under layer》
The hollow under layer is composed of hollow particles, a thermoplastic resin, a self-crosslinking acrylic resin, and, if necessary, other components. By using the under layer, the surface of the support can be smoothed or the wettability of the surface can be adjusted. As a result, the thickness of the heat-sensitive adhesive layer can be made uniform, and variations in the degree of activation due to heat can be suppressed. . Moreover, it is especially preferable to use a hollow particle (hollow filler) from the point of the thermal responsiveness of adhesive expression.
Therefore, by using the hollow under layer, a material excellent in thermal responsiveness suitable for thermal head activity can be obtained.

<Hollow particles>
The hollow particles used for the hollow under layer have an average particle diameter of 2.0 to 5.0 μm having a heat insulating effect and a hollow ratio of 70% or more in consideration of the problem of low energy thermal activation (high sensitivity thermal activation). Hollow particles are preferred. More preferably, the hollow particles have a maximum particle size of 10.0 μm or less and an average particle size of 2.0 to 5.0 μm and a hollow rate of 70% or more. Those having a low hollow ratio have insufficient heat insulation effect, so that heat energy from the thermal head is released to the outside through the support, and the high sensitivity thermal activation effect is poor. The hollow particles as referred to in the present invention are hollow particles that are already foamed with a thermoplastic resin as a shell and containing air or other gas inside.
The “hollow rate” is a ratio of the diameter of the hollow portion of the hollow particle to the outer diameter, and is represented by the following formula.
Hollow ratio (%) = [(Diameter of hollow part of hollow particle) / (Outer diameter of hollow particle)] × 100
In addition, when the average particle size is larger than 5.0 μm, when a heat-sensitive adhesive layer is provided on the intermediate under layer using these, a large particle portion can be a portion where the heat-sensitive adhesive layer is not formed, When activated, the adhesive strength tends to decrease. On the other hand, when it is smaller than 2.0 μm, it becomes difficult to ensure a hollow ratio of 70% or more, and as a result, the highly sensitive thermal activation effect is inferior.
Moreover, in order to ensure the adhesive force by the thermal activation system using a thermal head, the hollow ratio of the hollow particles used for the intermediate layer is preferably 70% or more.
As a material for forming the hollow particles satisfying the above conditions, an acrylonitrile-vinylidene chloride-methyl methacrylate copolymer or an acrylonitrile-methacrylonitrile-isobornyl methacrylate copolymer is preferable.

<Thermoplastic resin>
As the thermoplastic resin, various known ones can be used. For example, polyvinyl chloride, polyvinyl acetate, vinyl chloride vinyl acetate copolymer, ethyl cellulose, polystyrene, styrene copolymer, phenoxy resin, polyester, aromatic Group polyester, polyurethane, polycarbonate, polyacrylic acid ester, polymethacrylic acid ester, acrylic acid copolymer, maleic acid copolymer, polyvinyl alcohol, modified polyvinyl alcohol, hydroxyethyl cellulose, carboxymethyl cellulose, starches, etc. . In particular, when a resin similar to the thermoplastic resin used in the heat-sensitive adhesive layer described later is used, the compatibility between the resins in both layers and the interfacial binding properties are improved, so that the glass transition temperature (Tg) is −70 ° C. A (meth) acrylic copolymer in the range of -5 ° C is preferable. For example, a natural rubber latex obtained by graft copolymerization with a vinyl monomer, an acrylic ester copolymer, a methacrylic ester copolymer, an acrylic ester. It is preferable to use at least one selected from a methacrylate ester copolymer, an acrylic ester-styrene copolymer, an acrylic ester-methacrylic ester-styrene copolymer, and an ethylene-vinyl acetate copolymer. In particular, when a copolymer containing 2-ethylhexyl acrylate as a main component is used, it is well-familiar with the adherend and can be firmly bonded.
The Tg of the thermoplastic resin in the intermediate underlayer of the present invention is preferably adjusted to -70 ° C or higher and -30 ° C or lower. When the temperature is lower than -70 ° C, for example, a sticking phenomenon with an opposite surface when stored in a roll shape occurs, which causes a practical problem. Conversely, when a material having a temperature higher than −30 ° C. is used, the heat-sensitive adhesive layer after thermal activation is low in flexibility and adheres to a smooth surface such as glass, but the adherend surface is not smooth. Can not stick well because of point contact.

<Self-crosslinking acrylic resin>
The self-crosslinking acrylic resin used in the present invention has functional groups capable of reacting with each other in the acrylic resin to form a crosslinked structure, and the functional groups are brought into contact with each other at high temperature at room temperature or by heating. As a result of cross-linking, the polymer is polymerized to obtain a high strength coating film.
However, you may use a catalyst as needed.
Examples of functional groups include methylol groups, hydroxyl groups, carboxyl groups, amino groups, amide groups, epoxy groups, glycidyl groups, aziridine groups, oxazoline groups, carbon diimide groups, alkoxysilane groups, and the like. What is necessary is just to select the combination to obtain.
In the case of a group capable of self-condensation such as a methylol group or an alkoxysilane group, a resin containing this group alone may be used. In order to obtain a coating film with higher strength, those having a methylol group and a hydroxyl group are preferred. Such a resin is polymerized by the cross-linking formation of terminal methylol groups and hydroxyl groups by dehydration and / or de-HCHO reaction, and the coating strength is remarkably improved.
As the acrylic monomer, methyl methacrylate, ethyl methacrylate, acrylic acid, acrylamide, diacetone acrylamide, N-methylol acrylamide, 2-hydroxyethyl methacrylate, glycidyl methacrylate, polyoxyethylene methacrylate and the like can be used. Specific examples include a copolymer of N-methylolamide and hydroxyethyl methacrylate or acrylic acid, a copolymer of glycidyl methacrylate and acrylic acid or dimethylaminoethyl acrylate, hydroxyethyl methacrylate and acrylic acid or acrolein. And a copolymer.
The self-crosslinking acrylic resin having a methylol group and a hydroxyl group, which is a preferred resin of the present invention, can be obtained by emulsion polymerization of the acrylic monomer having a methylol group or a hydroxyl group. That is, N-methylol acrylamide having a methylol group, 2-hydroxyethyl methacrylate having a hydroxyl group, (meth) acrylic acid alkyl (carbon number 1 to 18) ester as an acrylic monomer constituting the resin, and the like. It can be obtained by emulsion polymerization at a predetermined molar ratio.
The acrylic polymer as described above is generally added in the form of an emulsion. The acrylic polymer preferably has a glass transition temperature of 0 ° C. or less from the viewpoint of achieving both adhesiveness and adhesive residue.

In addition to the above, other hollow underlayers include, for example, a natural rubber latex obtained by graft copolymerization with a vinyl monomer, an acrylic ester copolymer, a methacrylic ester copolymer, an acrylic ester-methacrylic ester copolymer, Mixing and using emulsion such as acrylic ester-styrene copolymer, acrylic ester-methacrylic ester-styrene copolymer, ethylene-vinyl acetate copolymer, and water-soluble resin such as polyvinyl alcohol (PVA). Also good.
The composition ratio of the hollow particles in the hollow under layer is preferably 0.1 to 1.0 part by weight of the hollow particles with respect to 1 part by weight of the resin component. When the amount of hollow particles is less than 0.1 parts by weight, the high-sensitivity thermal activation effect is inferior and the blocking resistance is further lowered. On the contrary, if it exceeds 1.0 part by weight, the tearing resistance at the time of peeling is inferior, and thus the peeling adhesive strength is reduced.
The coating amount of the intermediate under layer is generally 0.2 to 10 g / ^{m 2} on a dry coating amount is preferably in the range of 1 to 5 g / ^{m 2.} If the coating amount is less than 0.2 g / m ² , the heat insulation effect at the time of thermal activation cannot be obtained, and if it exceeds 10 g / m ² , the adhesive strength and the heat insulation effect are saturated, which is not economically preferable.

《Thermosensitive adhesive layer》
The heat-sensitive pressure-sensitive adhesive layer contains a solid plasticizer, a thermoplastic resin, and a tackifier, and further contains other components as necessary.

〔上記一般式（１）中、Ｒ^１とＲ^２は、互いに同一でも異なっていてもよく、水素原子、アルキル基、及びα，α−ジメチルベンジル基の何れかを表す。Ｘは、水素原子、又はハロゲン原子を表す。〕
一般式（１）におけるアルキル基としては、炭素数が１〜８のものが好ましく、例えば、メチル基、エチル基、ｎ−プロピル基、ｎ−ブチル基、ｎ−ペンチル基、ｎ−ヘキシル基、ｎ−ヘプチル基などが挙げられ、これらは置換基で更に置換されていてもよい。
置換基としては、水酸基、ハロゲン原子、ニトロ基、カルボキシル基、シアノ基、特定の置換基（例えば、ハロゲン原子、ニトロ基）を有していてもよいアルキル基、アリール基、複素環基などが挙げられる。ハロゲン原子としては、フッ素原子、塩素原子、臭素原子、ヨウ素原子が挙げられる。
一般式（１）で表されるベンゾトリアゾール化合物の具体例としては、２−（２′−ヒドロキシ−５′−メチルフェニル）ベンゾトリアゾール、２−（２′−ヒドロキシ−５′−ｔ−オクチルフェニル）ベンゾトリアゾール、２−（２′−ヒドロキシ−３′−ｔ−ブチル−５′−メチルフェニル）−５−クロロベンゾトリアゾール、２−（２′−ヒドロキシ−３′，５′−ジ−ｔ−アミルフェニル）ベンゾトリアゾール、２−（２′−ヒドロキシ−３′，５′−ｔ−ブチルフェニル）−５−クロロベンゾトリアゾール、２−〔２′−ヒドロキシ−３′，５′−ジ（１，１−ジメチルベンジル）フェニル〕ベンゾトリアゾール、２−（２′−ヒドロキシ−３′，５′−ジ−ｔ−ブチルフェニル）ベンゾトリアゾール、２−（２′−ヒドロキシ−３′−ｓｅｃ−ブチル−５′−ｔ−ブチルフェニル）ベンゾトリアゾール、２−（３′−ｔ−ブチル−５′−メチル−２′−ヒドロキシフェニル）−５−クロロベンゾトリアゾールなどが挙げられる。
これらは、１種を単独で使用してもよいし、２種以上を併用してもよい。 <Solid plasticizer>
Examples of the solid plasticizer used in the present invention include a benzotriazole compound represented by the following general formula (1), a hydroxybenzoic acid ester compound represented by the following general formula (2), and the following general formula (3) (4). ) (5), and compounds represented by (6) and (7).
<General formula (1)>

[In the general formula (1), R ¹ and R ² may be the same or different from each other, and represent any of a hydrogen atom, an alkyl group, and an α, α-dimethylbenzyl group. X represents a hydrogen atom or a halogen atom. ]
As an alkyl group in General formula (1), a C1-C8 thing is preferable, for example, a methyl group, an ethyl group, n-propyl group, n-butyl group, n-pentyl group, n-hexyl group, An n-heptyl group and the like can be mentioned, and these may be further substituted with a substituent.
Examples of the substituent include a hydroxyl group, a halogen atom, a nitro group, a carboxyl group, a cyano group, an alkyl group optionally having a specific substituent (for example, a halogen atom, a nitro group), an aryl group, a heterocyclic group, and the like. Can be mentioned. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.
Specific examples of the benzotriazole compound represented by the general formula (1) include 2- (2′-hydroxy-5′-methylphenyl) benzotriazole and 2- (2′-hydroxy-5′-t-octylphenyl). ) Benzotriazole, 2- (2'-hydroxy-3'-t-butyl-5'-methylphenyl) -5-chlorobenzotriazole, 2- (2'-hydroxy-3 ', 5'-di-t-) Amylphenyl) benzotriazole, 2- (2'-hydroxy-3 ', 5'-t-butylphenyl) -5-chlorobenzotriazole, 2- [2'-hydroxy-3', 5'-di (1, 1-dimethylbenzyl) phenyl] benzotriazole, 2- (2'-hydroxy-3 ', 5'-di-t-butylphenyl) benzotriazole, 2- (2'-hydroxy- '-Sec-butyl-5'-t-butylphenyl) benzotriazole, etc. 2- (3'-t- butyl-5'-methyl-2'-hydroxyphenyl) -5-chloro benzotriazole.
These may be used individually by 1 type and may use 2 or more types together.

〔上記一般式（２）中、Ｒ^３は、アルキル基、アルケニル基、アラルキル基、及びアリール基の何れかを表し、これらは更に置換基により置換されていてもよい。〕
一般式（２）におけるアルキル基としては、炭素数１〜１８のものが挙げられ、例えば、メチル基、エチル基、ｎ−プロピル基、ｎ−ブチル基、ｎ−ペンチル基、ｎ−ヘキシル基、ｎ−ヘプチル基、ｎ−オクチル基、ｎ−ノニル基、ｎ−デシル基等の直鎖状アルキル基；イソブチル基、イソアミル基、２−メチルブチル基、２−メチルペンチル基、３−メチルペンチル基、４−メチルペンチル基、２−エチルブチル基、２−メチルヘキシル基、３−メチルヘキシル基、４−メチルヘキシル基、５−メチルヘキシル基、２−エチルペンチル基、３−エチルペンチル基、２−メチルヘプチル基、３−メチルヘプチル基、４−メチルヘプチル基、５−メチルヘプチル基、２−エチルヘキシル基、３−エチルヘキシル基、イソプロピル基、ｓｅｃ−ブチル基、１−エチルプロピル基、１−メチルブチル基、１，２−ジメチルプロピル基、１−メチルヘプチル基、１−エチルブチル基、１，３−ジメチルブチル基、１，２−ジメチルブチル基、１−エチル−２−メチルプロピル基、１−メチルヘキシル基、１−エチルヘプチル基、１−プロピルブチル基、１−イソプロピル−２−メチルプロピル基、１−エチル−２−メチルブチル基、１−プロピル−２−メチルプロピル基、１−エチルヘキシル基、１−プロピルペンチル基、１−イソプロピルペンチル基、１−イソプロピル−２−メチルブチル基、１−イソプロピル−３−メチルブチル基、１−メチルオクチル基、１−プロピルヘキシル基、１−イソブチル−３−メチルブチル基、ネオペンチル基、ｔｅｒｔ−ブチル基、ｔｅｒｔ−ヘキシル基、ｔｅｒｔ−アミル基、ｔｅｒｔ−オクチル基等の分岐状アルキル基；シクロヘキシル基、４−メチルシクロヘキシル基、４−エチルシクロヘキシル基、４−ｔｅｒｔ−ブチルシクロヘキシル基、４−（２−エチルヘキシル）シクロヘキシル基、ボルニル基、イソボルニル基、アダマンチル基等のシクロアルキル基などが挙げられ、これらは更に置換基により置換されていてもよい。
一般式（２）におけるアルケニル基としては、炭素数２〜８のものが好適であり、例えば、ビニル基、アリル基、１−プロペニル基、メタクリル基、クロチル基、１−ブテニル基、３−ブテニル基、２−ペンテニル基、４−ペンテニル基、２−ヘキセニル基、５−ヘキセニル基、２−ヘプテニル基、２−オクテニル基等が挙げられ、これらは更に置換基により置換されていてもよい。
一般式（２）におけるアラルキル基としては、特に制限はなく、目的に応じて適宜選定することができ、例えば、ベンジル基、フェニルエチル基、フェニルプロピル基等が挙げられ、これらは更に置換基により置換されていてもよい。
一般式（２）におけるアリール基としては、例えば、フェニル基、ナフチル基、アントラニル基、フルオレニル基、フェナレニル基、フェナントラニル基、トリフェニレニル基、ピレニル基等が挙げられ、これらは更に置換基により置換されていてもよい。
前記アルキル基、アルケニル基、アラルキル基、又はアリール基の置換基としては、水酸基、ハロゲン原子、ニトロ基、カルボキシル基、シアノ基、特定の置換基（例えば、ハロゲン原子、ニトロ基）を有していてもよいアルキル基、アリール基、複素環基などが挙げられる。
一般式（２）で表されるヒドロキシ安息香酸エステル化合物の具体例としては、ｍ−ヒドロキシ安息香酸メチル、ｍ−ヒドロキシ安息香酸エチル、ｍ−ヒドロキシ安息香酸フェニル、ｐ−ヒドロキシ安息香酸メチル、ｐ−ヒドロキシ安息香酸エチル、ｐ−ヒドロキシ安息香酸ｎ−プロピル、ｐ−ヒドロキシ安息香酸ｎ−ブチル、ｐ−ヒドロキシ安息香酸ステアリル、ｐ−ヒドロキシ安息香酸シクロヘキシル、ｐ−ヒドロキシ安息香酸ベンジル、ｐ−ヒドロキシ安息香酸４−クロロベンジル、ｐ−ヒドロキシ安息香酸４−メチルベンジル、ｐ−ヒドロキシ安息香酸フェニルなどが挙げられる。
これらは、１種を単独で使用してもよいし、２種以上を併用してもよい。 <General formula (2)>

[In the general formula (2), R ³ represents any one of an alkyl group, an alkenyl group, an aralkyl group, and an aryl group, which may be further substituted with a substituent. ]
As an alkyl group in General formula (2), a C1-C18 thing is mentioned, For example, a methyl group, an ethyl group, n-propyl group, n-butyl group, n-pentyl group, n-hexyl group, linear alkyl groups such as n-heptyl group, n-octyl group, n-nonyl group, n-decyl group; isobutyl group, isoamyl group, 2-methylbutyl group, 2-methylpentyl group, 3-methylpentyl group, 4-methylpentyl group, 2-ethylbutyl group, 2-methylhexyl group, 3-methylhexyl group, 4-methylhexyl group, 5-methylhexyl group, 2-ethylpentyl group, 3-ethylpentyl group, 2-methyl Heptyl, 3-methylheptyl, 4-methylheptyl, 5-methylheptyl, 2-ethylhexyl, 3-ethylhexyl, isopropyl, sec-butyl Group, 1-ethylpropyl group, 1-methylbutyl group, 1,2-dimethylpropyl group, 1-methylheptyl group, 1-ethylbutyl group, 1,3-dimethylbutyl group, 1,2-dimethylbutyl group, 1 -Ethyl-2-methylpropyl group, 1-methylhexyl group, 1-ethylheptyl group, 1-propylbutyl group, 1-isopropyl-2-methylpropyl group, 1-ethyl-2-methylbutyl group, 1-propyl- 2-methylpropyl group, 1-ethylhexyl group, 1-propylpentyl group, 1-isopropylpentyl group, 1-isopropyl-2-methylbutyl group, 1-isopropyl-3-methylbutyl group, 1-methyloctyl group, 1-propyl Hexyl group, 1-isobutyl-3-methylbutyl group, neopentyl group, tert-butyl group, tert-hexyl Branched alkyl groups such as tert-amyl group and tert-octyl group; cyclohexyl group, 4-methylcyclohexyl group, 4-ethylcyclohexyl group, 4-tert-butylcyclohexyl group, 4- (2-ethylhexyl) cyclohexyl group, Examples thereof include a cycloalkyl group such as a bornyl group, an isobornyl group, and an adamantyl group, and these may be further substituted with a substituent.
As an alkenyl group in General formula (2), a C2-C8 thing is suitable, for example, a vinyl group, an allyl group, 1-propenyl group, a methacryl group, a crotyl group, 1-butenyl group, 3-butenyl. Group, 2-pentenyl group, 4-pentenyl group, 2-hexenyl group, 5-hexenyl group, 2-heptenyl group, 2-octenyl group and the like, and these may be further substituted with a substituent.
There is no restriction | limiting in particular as an aralkyl group in General formula (2), According to the objective, it can select suitably, For example, a benzyl group, a phenylethyl group, a phenylpropyl group etc. are mentioned, These are further substituted by a substituent. May be substituted.
Examples of the aryl group in the general formula (2) include a phenyl group, a naphthyl group, an anthranyl group, a fluorenyl group, a phenalenyl group, a phenanthranyl group, a triphenylenyl group, and a pyrenyl group, which are further substituted with a substituent. May be.
The alkyl group, alkenyl group, aralkyl group, or aryl group has a hydroxyl group, a halogen atom, a nitro group, a carboxyl group, a cyano group, or a specific substituent (for example, a halogen atom or a nitro group). Examples thereof may include an alkyl group, an aryl group, and a heterocyclic group.
Specific examples of the hydroxybenzoic acid ester compound represented by the general formula (2) include methyl m-hydroxybenzoate, ethyl m-hydroxybenzoate, phenyl m-hydroxybenzoate, methyl p-hydroxybenzoate, p- Ethyl hydroxybenzoate, n-propyl p-hydroxybenzoate, n-butyl p-hydroxybenzoate, stearyl p-hydroxybenzoate, cyclohexyl p-hydroxybenzoate, benzyl p-hydroxybenzoate, p-hydroxybenzoic acid 4 -Chlorobenzyl, 4-methylbenzyl p-hydroxybenzoate, phenyl p-hydroxybenzoate and the like.
These may be used individually by 1 type and may use 2 or more types together.

〔上記一般式（３）中、Ｒ^４とＲ^５は、互いに同一でも異なっていてもよく、アルキル基又はアルコキシ基を表す。Ｙは、水素原子又は水酸基を表す。〕 <General formula (3)>

[In said general formula (3), R < ⁴ > and R < ⁵ > may mutually be same or different and represent an alkyl group or an alkoxy group. Y represents a hydrogen atom or a hydroxyl group. ]

〔上記一般式（４）中、Ｒ^６は、水素原子、ハロゲン原子、アルキル基、及びアルコキシ基の何れかを表す。Ｙは、水素原子又は水酸基を表す。〕 <General formula (4)>

[In General Formula (4), R ⁶ represents any one of a hydrogen atom, a halogen atom, an alkyl group, and an alkoxy group. Y represents a hydrogen atom or a hydroxyl group. ]

〔上記一般式（５）中、Ｒ^７は、水素原子、ハロゲン原子、アルキル基、及びアルコキシ基の何れかを表す。〕 <General formula (5)>

[In the general formula (5), R ⁷ represents any one of a hydrogen atom, a halogen atom, an alkyl group, and an alkoxy group. ]

In the general formulas (3) to (5), examples of the alkyl group include those similar to the general formula (1).
Examples of the alkoxy group include methoxy group, ethoxy group, propyloxy group, i-propyloxy group, butoxy group, i-butoxy group, t-butoxy group, pentyloxy group, hexyloxy group, cyclohexyloxy group, heptyl. Examples thereof include an oxy group, an octyloxy group, a 2-ethylhexyloxy group, a nonyloxy group, a decyloxy group, a 3,7-dimethyloctyloxy group, and a lauryloxy group.

Specific examples of the compound represented by the general formula (3) include toluoin, anisoin, m-anisoin, deoxytoluoin, deoxyanisoin, 4,4'-diethylbenzoin, 4,4'-diethoxybenzoin and the like. Can be mentioned.
These may be used individually by 1 type and may use 2 or more types together.
Specific examples of the compound represented by the general formula (4) include phenyl 1-hydroxy-2-naphthoate, 1-hydroxy-2-naphthoic acid-p-chlorophenyl, 1-hydroxy-2-naphthoic acid-o-. Chlorophenyl, 1-hydroxy-2-naphthoic acid-p-methylphenyl, 1-hydroxy-2-naphthoic acid-o-methylphenyl, 1,4-dihydroxy-2-naphthoic acid phenyl, 1,4-dihydroxy-2- Examples thereof include naphthoic acid-p-chlorophenyl and 1,4-dihydroxy-2-naphthoic acid-o-chlorophenyl.
These may be used individually by 1 type and may use 2 or more types together.
Specific examples of the compound represented by the general formula (5) include benzoic acid-3-hydroxyphenyl, benzoic acid-4-hydroxyphenyl, benzoic acid-2-hydroxyphenyl, and o-methylbenzoic acid-3-hydroxyphenyl. , P-chlorobenzoic acid-3-hydroxyphenyl and the like. These may be used individually by 1 type and may use 2 or more types together.

＜一般式（７）＞

一般式（６）（７）において、Ｒは、炭素数１〜４の分岐していてもよいアルキル基を表し、例えば、メチル基、エチル基、プロピル基、ブチル基、ｔ−ブチル基などが挙げられる。ｎは、１〜５の整数を表す。 <General formula (6)>

<General formula (7)>

In the general formulas (6) and (7), R represents an alkyl group having 1 to 4 carbon atoms which may be branched, and examples thereof include a methyl group, an ethyl group, a propyl group, a butyl group, and a t-butyl group. Can be mentioned. n represents an integer of 1 to 5.

Specific examples of the compound represented by the general formula (6) include triphenylphosphine, tri-m-tolylphosphine, tri-p-tolylphosphine, tri-o-tolylphosphine, tri-2,4-xylenephosphine, Examples include tri-2,5-xylene phosphine, tri-2,6-xylene phosphine, tri-3,4-xylene phosphine, and tri-3,5-xylene phosphine.
These compounds may be used individually by 1 type, and may use 2 or more types together.
Specific examples of the compound represented by the general formula (7) include tris (o-methoxyphenyl) phosphine, tris (m-methoxyphenyl) phosphine, tris (p-methoxyphenyl) phosphine, and tris (p-ethoxyphenyl). Phosphine, tris (pn-propyloxyphenyl) phosphine, tris (mt-butoxyphenyl) phosphine, tris (mn-butoxyphenyl) phosphine, tris (pn-butoxyphenyl) phosphine, tris (p -T-butoxyphenyl) phosphine, tris (mt-butoxyphenyl) phosphine, and the like.
These compounds may be used individually by 1 type, and may use 2 or more types together.

  In addition to the general formulas (1) to (7), any compound that is solid at room temperature and can be mixed with a thermoplastic resin when heated and melted can be used as the solid plasticizer of the present invention. It is. Specific examples of such compounds include 2,2-ethylidene-bis- (4,6-di-t-butylphenol), bis (3,5-di-t-butyl-4-hydroxybenzyl) sulfide, 2 -(3,5-di-t-butyl-4-hydroxybenzyl) -2-n-butylmalonate bis (1,2,2,6,6-pentamethyl-4-piperidyl), 1,6-hexanediol Bis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], 3.9 bis {2- [3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionyl Oxy] -1,1-dimethylethyl} -2,4-6- (1H, 3H, 5H) trione, 2,4-di-t-pentylphenyl-3,5-di-t-butyl-4-hydroxy Benzoate, 2,2'-me Renbis [6- (1-methylcyclohexyl) -p-cresol], 4,4'-methylenebis (2,6-di-t-butylphenol), 1,4-dihydroxy-2-naphthoic acid phenyl ester, 2,2 '-Butylidenebis (4-methyl-6-tert-butylphenol), 2,2', 4,4'-tetrahydroxybenzophenone, 4-benzyloxy-2-hydroxybenzophenone, 2- (4,6-diphenyl-1, 3,5-triazin-2-yl) -5 [(hexyl) oxy] phenol, 6- [3- (3-tert-butyl-4-hydroxy-5-methylpropoxy) -2,4,8,10- Tetra-t-butyldibenz [d, f] [1,3,2] -dioxaphosphine, phosphoric ester amide, 2- (4'-morpholinodithio) benzothia Lumpur, 1-o-tolylbiguanide, O, O'dibenzamidodiphenyl disulfide, tris (2,4-di -t- butyl-phenyl) phosphite, 2-naphthyl benzoate.

<Thermoplastic resin>
The thermoplastic resin used in the heat-sensitive adhesive layer of the present invention preferably has a glass transition point of −70 ° C. or higher and lower than −20 ° C. There is no restriction | limiting in particular as such a thermoplastic resin, According to the objective, it can select suitably. Specific examples of the thermoplastic resin are shown below.
The types of thermoplastic resins are (meth) acrylic acid ester copolymer, styrene-isoprene copolymer, styrene-acrylic acid ester copolymer, styrene-butadiene copolymer, acrylonitrile-butadiene copolymer, ethylene- Vinyl acetate copolymer, vinyl acetate-acrylic acid ester copolymer, ethylene-vinyl chloride copolymer, ethylene-acrylic acid ester copolymer, vinyl acetate-ethylene-vinyl chloride copolymer, vinyl acetate-ethylene-acrylic Examples thereof include resins such as acid ester copolymers, vinyl acetate-ethylene-styrene copolymers, polybutadiene, and polyurethane. Among these, from the viewpoint of adhesiveness and weather resistance, it is preferable to use various copolymers having an acrylate ester as a monomer component, and these are used alone or in combination.

<Tackifier>
The tackifier is added to improve the adhesive strength of the heat-sensitive adhesive layer, and is not particularly limited and can be appropriately selected from known ones according to the purpose. For example, rosin derivatives (rosin, Polymerized rosin, hydrogenated rosin, etc.), terpene resins (terpene resins, aromatic modified terpene resins, terpene phenol resins, hydrogenated terpene resins, etc.), petroleum resins, phenol resins, xylene resins and the like. These tackifiers are compatible with the thermoplastic resin and the hot melt material, and can significantly improve the adhesive strength of the heat-sensitive adhesive layer.
The coating amount of the heat-sensitive adhesive layer is usually 3 to 20 g / ^{m 2} on a dry coating amount is preferably in the range of 5 to 15 g / ^{m 2.} If the coating amount is less than 3 g / m ² , sufficient adhesive strength cannot be obtained when performing adhesion by heating, and if it exceeds 20 g / m ² , the heat insulating effect of the intermediate layer is diminished, which is economically undesirable.
There is no restriction | limiting in particular in the formation method of a heat-sensitive adhesive layer, It can form by well-known methods, such as a coating method and a printing method. Examples of coating methods include blade coating, gravure coating, gravure offset coating, bar coating, roll coating, knife coating, air knife coating, comma coating, U comma coating, AKKU coating, and smoothing. Examples thereof include a coating method, a micro gravure coating method, a reverse roll coating method, a four or five roll coating method, a dip coating method, a falling curtain coating method, a slide coating method, and a die coating method.
In addition, as drying conditions at the time of application | coating or printing, you have to set it as the temperature range which the hot-melt substance to be used does not melt | dissolve. As a means for drying, in addition to hot air drying, a drying method using a heat source using infrared rays, microwaves, and high frequencies can be used.

In the heat-sensitive adhesive label sheet of the present invention, it is preferable to sequentially provide a recording layer or a recording layer and a protective layer on the side of the support that does not have the heat-sensitive adhesive layer, and further, if necessary, other layers. You may have.
The recording layer is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include a heat-sensitive recording layer, a heat-melt transfer recording ink-receiving layer, an electrophotographic toner image-receiving layer, and a silver halide photographic recording layer. , And an ink-jet ink image-receiving layer.
Among these, a heat-sensitive adhesive material provided with a heat-sensitive recording layer containing a leuco dye and a developer and a heat-sensitive adhesive material provided with an ink-receiving layer for thermal transfer recording are extremely useful.

<Thermosensitive adhesive material for thermal recording>
The heat-sensitive recording layer contains at least a color former such as a leuco dye, a developer, and a binder resin, and further contains other components such as a filler as necessary. The leuco dye is not particularly limited and can be appropriately selected from known ones according to the purpose. For example, triphenylmethane dyes, fluoran dyes, phenothiazine dyes, auramine dyes, spiropyran dyes, indolic dyes. And nophthalide dyes.
Specific examples of the leuco dye include 3,3-bis (p-dimethylaminophenyl) phthalide, 3,3-bis (p-dimethylaminophenyl) -6-dimethylaminophthalide (also called crystal violet lactone), 3, 3-bis (p-dimethylaminophenyl) -6-diethylaminophthalide, 3,3-bis (p-dimethylaminophenyl) -6-chlorophthalide, 3,3-bis (p-dibutylaminophenyl) phthalide, 3- Cyclohexylamino-6-chlorofluorane, 3-dimethylamino-5,7-dimethylfluorane, 3-diethylamino-7-chlorofluorane, 3-diethylamino-7-methylfluorane, 3-diethylamino-7,8- Benzfluorane, 3-diethylamino-6-methyl-7-chlorofluorane, 3- (N p-tolyl-N-ethylamino) -6-methyl-7-anilinofluorane, 3-pyrrolidino-6-methyl-7-anilinofluorane, 2- {N- (3'-trifluoromethylphenyl) Amino} -6-diethylaminofluorane, 3-diethylamino-6-methyl-7- (m-trichloromethylanilino) fluorane, 3-diethylamino-7- (o-chloroanilino) fluorane, 3-dibutylamino-7- ( o-chloroanilino) fluorane, 3-N-methyl-N-amylamino-6-methyl-7-anilinofluorane, 3-N-methyl-N-cyclohexylamino-6-methyl-7-anilinofluorane, 3 -Diethylamino-6-methyl-7-anilinofluorane, 3- (N, N-diethylamino) -5-methyl-7- (N, N- Benzylamino) fluorane, benzoylleucomethylene blue, 6'-chloro-8'-methoxy-benzoindolino-pyrospirane, 6'-bromo-3'-methoxy-benzoindolino-pyrospirane, 3- (2'-hydroxy-4 '-Dimethylaminophenyl) -3- (2'-methoxy-5'-chlorophenyl) phthalide, 3- (2'-hydroxy-4'-dimethylaminophenyl) -3- (2'-methoxy-5'- Nitrophenyl) phthalide, 3- (2'-hydroxy-4'-diethylaminophenyl) -3- (2'-methoxy-5'-methylphenyl) phthalide, 3-diethylamino-6-methyl-7- (2 ', 4'-dimethylanilino) fluorane, 3- (2'-methoxy-4'-dimethylaminophenyl) -3- (2'-hy Droxy-4'-chloro-5'-methylphenyl) phthalide, 3-morpholino-7- (N-propyl-trifluoromethylanilino) fluorane, 3-pyrrolidino-7-trifluoromethylanilinofluorane, 3- Diethylamino-5-chloro-7- (N-benzyl-trifluoromethylanilino) fluorane, 3-pyrrolidino-7- (di-p-chlorophenyl) methylaminofluorane, 3-diethylamino-5-chloro-7- (Α-phenylethylamino) fluorane, 3- (N-ethyl-p-toluidino) -7- (α-phenylethylamino) fluorane, 3-diethylamino-7- (o-methoxycarbonylphenylamino) fluorane, 3- Diethylamino-5-methyl-7- (α-phenylethylamino) fluorane, 3-die Ruamino-7-piperidinofluorane, 2-chloro-3- (N-methyltoluidino) -7- (pn-butylanilino) fluorane, 3- (N-benzyl-N-cyclohexylamino) -5,6- Benzo-7-α-naphthylamino-4'-o-bromofluorane, 3-diethylamino-6-methyl-7-mesitidino-4 ', 5'-benzofluorane, 3-diethylamino-6-methyl-7- (2 ', 4'-dimethylanilino) fluorane, 3- (p-dimethylaminophenyl) -3- {1,1-bis (p-dimethylaminophenyl) ethylene-2-yl} phthalide, 3- (p -Dimethylaminophenyl) -3- {1,1-bis (p-dimethylaminophenyl) ethylene-2-yl} -6-dimethylaminophthalide, 3- (p-dimethylamino) Phenyl) -3- (1-p-dimethylaminophenyl-1-phenylethylene-2-yl) phthalide, 3- (p-dimethylaminophenyl-3- (1-p-dimethylaminophenyl-1-p-chlorophenyl) Ethylene-2-yl) -6-dimethylaminophthalide, 3- (4'-dimethylamino-2'-methoxy) -3- (1 "-p-dimethylaminophenyl-1" -p-chlorophenyl-1 " , 3 ″ -butadiene-4 ″ -yl) benzophthalide, 3- (4′-dimethylamino-2′-benzyloxy) -3- (1 ″ -p-dimethylaminophenyl-1 ″ -phenyl-1 ″, 3 "-Butadiene-4" -yl) benzophthalide, 3-dimethylamino-6-dimethylamino-fluorene-9-spiro-3 '-(6'-dimethylamino) phthalide, 3 3-bis {2- (p-dimethylaminophenyl) -2- (p-methoxyphenyl) ethenyl} -4,5,6,7-tetrachlorophthalide, 3-bis {1,1-bis (4- Pyrrolidinophenyl) ethylene-2-yl} -5,6-dichloro-4,7-dibromophthalide, bis (p-dimethylaminostyryl) -1-naphthalenesulfonylmethane, 3- (N-methyl-N-propyl) Amino) -6-methyl-7-anilidefluorane, 3-diethylamino-6-methyl-7-anilinofluorane, 3,6-bis (dimethylamino) fluorane spiro (9,3 ')-6'- Dimethylaminophthalide, 3-diethylamino-6-chloro-7-anilinofluorane, 3-N-ethyl-N- (2-ethoxypropyl) amino-6-methyl-7-anilinofur Lan, 3-N-ethyl-N-tetrahydrofurfurylamino-6-methyl-7-anilinofluorane, 3-diethylamino-6-methyl-7-mesitidino-4 ', 5'-benzofluorane, 3- N-methyl-N-isobutyl-6-methyl-7-anilinofluorane, 3-N-ethyl-N-isoamyl-6-methyl-7-anilinofluorane and the like can be mentioned. These may be used individually by 1 type and may use 2 or more types together.

The developer is not particularly limited and can be appropriately selected from known electron-accepting compounds according to the purpose. For example, phenolic compounds, thiophenolic compounds, thiourea derivatives, organic acids or their A metal salt etc. are mentioned.
Specific examples of the developer include 4,4'-isopropylidenebisphenol, 3,4'-isopropylidenebisphenol, 4,4'-isopropylidenebis (o-methylphenol), 4,4'-s-butyl Ridenbisphenol, 4,4'-isopropylidenebis (ot-butylphenol), 4,4'-cyclohexylidenediphenol, 4,4'-isopropylidenebis (2-chlorophenol), 2,2'-methylenebis (4-methyl-6-t-butylphenol), 2,2'-methylenebis (4-ethyl-6-t-butylphenol), 4,4'-butylidenebis (6-t-butyl-2-methyl) phenol, 1 , 1,3-Tris (2-methyl-4-hydroxy-5-t-butylphenyl) butane, 1,1,3-tris (2-methyl 4-hydroxy-5-cyclohexylphenyl) butane, 4,4'-thiobis (6-tert-butyl-2-methyl) phenol, 4,4'-diphenolsulfone, 4,2'-diphenolsulfone, 4- Isopropoxy-4'-hydroxydiphenylsulfone, 4-benzyloxy-4'-hydroxydiphenylsulfone, 4,4'-diphenol sulfoxide, isopropyl P-hydroxybenzoate, benzyl P-hydroxybenzoate, benzyl protocatechuate, gallic acid Stearyl, lauryl gallate, octyl gallate, 1,7-bis (4-hydroxyphenylthio) -3,5-dioxaheptane, 1,5-bis (4-hydroxyphenylthio) -3-oxaheptane, 1 , 3-bis (4-hydroxyphenylthio) -propane, 2, '-Methylenebis (4-ethyl-6-tert-butylphenol), 1,3-bis (4-hydroxyphenylthio) -2-hydroxypropane, N, N'-diphenylthiourea, N, N'-di (m -Chlorophenyl) thiourea, salicylanilide, 5-chloro-salicylanilide, salicyl-o-chloroanilide, 2-hydroxy-3-naphthoic acid, antipyrine complex of zinc thiocyanate, zinc of 2-acetyloxy-3-naphthoic acid Salts, 2-hydroxy-1-naphthoic acid, 1-hydroxy-2-naphthoic acid, metal salts of hydroxynaphthoic acid zinc, aluminum, calcium, etc., bis- (4-hydroxyphenyl) acetic acid methyl ester, bis- (4 -Hydroxyphenyl) acetic acid benzyl ester, 4- {β- (p-methoxyphenoxy) ethoxy } Salicylic acid, 1,3-bis (4-hydroxycumyl) benzene, 1,4-bis (4-hydroxycumyl) benzene, 2,4'-diphenolsulfone, 3,3'-diallyl-4,4 '-Diphenolsulfone, α, α-bis (4-hydroxyphenyl) -α-methyltoluene zinc antipyrine complex, tetrabromobisphenol A, tetrabromobisphenol S, 4,4'-thiobis (2-methylphenol) ), 3,4-dihydroxy-4'-methyl-diphenylsulfone, 4,4'-thiobis (2-chlorophenol), and the like. These may be used individually by 1 type and may use 2 or more types together.
There is no restriction | limiting in particular in the addition amount of the developer in a thermosensitive recording layer, According to the objective, it can select suitably, 1-20 weight part is preferable with respect to 1 weight part of leuco dye, and 2-10 weight part is more. preferable.

  There is no restriction | limiting in particular as binder resin, Although it can select suitably according to the objective from well-known things, For example, polyvinyl alcohol, starch, or its derivative; methoxycellulose, hydroxyethylcellulose, carboxymethylcellulose, methylcellulose, ethylcellulose, etc. Cellulose derivatives: sodium polyacrylate, polyvinylpyrrolidone, acrylamide-acrylic acid ester copolymer, acrylamide-acrylic acid ester-methacrylic acid terpolymer, styrene-maleic anhydride copolymer alkali salt, isobutylene-maleic anhydride In addition to water-soluble polymers such as acid copolymer alkali salts, polyacrylamide, sodium alginate, gelatin, and casein, polyvinyl acetate, polyurethane, polyacrylic acid, polyacrylic acid ester , Emulsions such as polymethacrylic acid ester, polybutyl methacrylate, vinyl chloride-vinyl acetate copolymer, ethylene-vinyl acetate copolymer; latexes such as styrene-butadiene copolymer, styrene-butadiene-acrylic copolymer Etc. These may be used individually by 1 type and may use 2 or more types together.

Various heat-fusible substances can be used as fillers in the heat-sensitive recording layer.
Specific examples of the heat-fusible substance include fatty acids such as stearic acid and behenic acid; fatty acid amides such as stearic acid amide and palmitic acid amide; zinc stearate, aluminum stearate, calcium stearate, zinc palmitate, behen Fatty acid metal salts such as zinc acid; p-benzylbiphenyl, terphenyl, triphenylmethane, benzyl p-benzyloxybenzoate, β-benzyloxynaphthalene, β-naphthoic acid phenyl ester, 1-hydroxy-2-naphthoic acid phenyl Ester, 1-hydroxy-2-naphthoic acid methyl ester, diphenyl carbonate, terephthalic acid dibenzyl ester, terephthalic acid dimethyl ester, 1,4-dimethoxynaphthalene, 1,4-diethoxynaphthalene, 1,4-dibenzyloxynaphtha 1,2-bis (phenoxy) ethane, 1,2-bis (3-methylphenoxy) ethane, 1,2-bis (4-methylphenoxy) ethane, 1,4-bis (phenoxy) butane, 1, 4-bis (phenoxy) -2-butene, 1,2-bis (4-methoxyphenylthio) ethane, dibenzoylmethane, 1,4-bis (phenylthio) butane, 1,4-bis (phenylthio) -2- Butene, 1,2-bis (4-methoxyphenylthio) ethane, 1,3-bis (2-vinyloxyethoxy) benzene, 1,4-bis (2-vinyloxyethoxy) benzene, p- (2-vinyl Oxyethoxy) biphenyl, p-aryloxybiphenyl, p-propargyloxybiphenyl, dibenzoyloxymethane, 1,3-dibenzoyloxypropane, di Disulfide, 1,1-diphenylethanol, 1,1-diphenylpropanol, p- (benzyloxy) benzyl alcohol, 1,3-diphenoxy-2-propanol, N-octadecylcarbamoyl-p-methoxycarbonylbenzene, N- Examples include octadecylcarbamoylbenzene, oxalic acid dibenzyl ester, 1,5-bis (p-methoxyphenyloxy) -3-oxapentane and the like.
These may be used individually by 1 type and may use 2 or more types together.

In the heat-sensitive recording layer, various auxiliary additive components such as a surfactant and a lubricant can be used in combination as other components as required. Examples of the lubricant include higher fatty acids or metal salts thereof, higher fatty acid amides, higher fatty acid esters, animal waxes, vegetable waxes, mineral waxes, petroleum waxes, and the like.
The method for forming the heat-sensitive recording layer is not particularly limited, and a generally known method can be adopted. For example, a leuco dye and a developer are separately added together with a binder resin and other components together with a ball mill, an atomizer, and the like. After pulverizing and dispersing with a disperser such as a lighter or sand mill until the dispersed particle size becomes 1 to 3 μm, mix with a filler, a heat-fusible substance (sensitizer) dispersion, etc., if necessary, with a constant formulation. A heat-sensitive recording layer coating solution may be prepared and coated on a support.
The thickness of the heat-sensitive recording layer varies depending on the composition of the heat-sensitive recording layer and the application of the heat-sensitive adhesive material, and cannot be specified unconditionally, but is preferably 1 to 50 μm, more preferably 3 to 20 μm.

<Thermosensitive adhesive material for thermal transfer recording>
The ink receiving layer for heat-melt transfer recording in the heat-sensitive adhesive material for heat transfer recording contains a filler, a binder resin, and a water-proofing agent, and further contains other components as necessary.
There is no restriction | limiting in particular in a filler, According to the objective, it can select suitably, For example, calcium carbonate, silica, titanium oxide, aluminum hydroxide, clay, baked clay, magnesium silicate, magnesium carbonate, white carbon, zinc oxide , Barium sulfate, surface-treated calcium carbonate and silica, urea-formalin resin, styrene-methacrylic acid copolymer, polystyrene and other fine powders.
There is no restriction | limiting in particular in binder resin, According to the objective, it can select suitably from well-known water-soluble resin, For example, polyvinyl alcohol, starch or its derivative, methoxycellulose, hydroxyethylcellulose, carboxymethylcellulose, methylcellulose, ethylcellulose Cellulose derivatives such as: polyacrylic acid soda, polyvinylpyrrolidone, acrylamide-acrylic acid ester copolymer, acrylamide-acrylic acid ester-methacrylic acid terpolymer, styrene-maleic anhydride copolymer alkali salt, isobutylene-anhydrous Examples include maleic copolymer alkali salts, water-soluble polymer compounds such as polyacrylamide, sodium alginate, gelatin, and casein. These may be used individually by 1 type and may use 2 or more types together.

The ratio of the filler and the binder resin in the ink receiving layer is preferably filler: binder resin (solid content) = 1: 0.1 to 0.2 (weight ratio) from the viewpoint of blocking resistance.
There is no restriction | limiting in particular in a water-proofing agent, According to the objective, it can select suitably, For example, formaldehyde, glyoxal, chromium alum, melamine, melamine-formaldehyde resin, polyamide resin, polyamide-epichlorohydrin resin etc. are mentioned.
The ratio of the water-proofing agent to the binder resin is also preferably binder resin (solid content): water-proofing agent = 1: 0.3 to 0.5 from the viewpoint of blocking resistance.
As described above, the ink receiving layer is formed by containing a filler and a water-soluble resin, and further containing a binder resin and a water-proofing agent in a specific ratio. Further, the surface of the ink receiving layer is smoothed by a calendar or the like. By processing at a temperature of 500 seconds or more, in addition to the effect of the filler, the print quality can be further improved.

-Protective layer-
The protective layer contains a resin component and other components as necessary. As the resin, a hydrophobic resin emulsion or a water-soluble resin can be used, but a film using a water-soluble resin is preferable from the viewpoint of barrier properties as a protective layer. In addition, when water-soluble resin is used, the function can be improved by making water resistance with a crosslinking agent. Polyvinyl alcohol is generally used as the water-soluble resin, but a combination with a crosslinking agent for water resistance can be appropriately selected and used.
Examples thereof include a combination of carboxy-modified polyvinyl alcohol and polyamide epichlorohydrin resin, polyvinyl alcohol having a reactive carbonyl group (PVAα) and a hydrazide compound. Among them, the protective layer containing PVAα and a hydrazide compound as a crosslinking agent has extremely high heat resistance and water resistance, and is hardly affected by the addition of pressure, temperature, and humidity, so that the blocking resistance can be greatly improved.
PVAα can be produced by a known method such as saponification of a polymer obtained by copolymerizing a vinyl monomer having a reactive carbonyl group and a fatty acid vinyl ester. Examples of the vinyl monomer having a reactive carbonyl group include a group having an ester residue and a group having an acetone group, and a vinyl monomer having a diacetone group is preferable.
Specific examples include diacetone acrylamide and metadiacetone acrylamide. Examples of the fatty acid vinyl ester include vinyl formate, vinyl acetate, and vinyl propionate. Among these, vinyl acetate is particularly preferable. PVAα may be a copolymer of other copolymerizable vinyl monomers. Examples of these copolymerizable vinyl monomers include acrylic acid esters, butadiene, ethylene, propylene, acrylic acid, methacrylic acid, maleic acid, maleic anhydride, itaconic acid and the like.
The content of the reactive carbonyl group in PVAα is preferably 0.5 to 20 mol% of the whole polymer, and more preferably 2 to 10 mol% in view of water resistance. If the content is less than 0.5 mol%, the practical water resistance is insufficient, and if it exceeds 20 mol%, the improvement in water resistance is not seen any more and the cost becomes high, which is not economical.
The polymerization degree of PVAα is preferably 300 to 3,000, more preferably 500 to 2,200. The saponification degree of PVAα is preferably 80% or more.

  The hydrazide compound is not particularly limited as long as it has a hydrazide group, and can be appropriately selected according to the purpose. Adipic acid dihydrazide, azelaic acid hydrazide, sebacic acid dihydrazide, dodecanedioic acid dihydrazide, maleic acid dihydrazide, fumaric acid hydrazide, itaconic acid dihydrazide, benzoic acid hydrazide, glutaric acid dihydrazide, diglycolic acid hydrazide dihydrazide dihydrazide dihydrazide Examples include acid hydrazide, terephthalic acid dihydrazide, 2,7-naphthoic acid dihydrazide, and polyacrylic acid hydrazide. Among these, adipic acid dihydrazide is particularly preferable in terms of water resistance and safety. These may be used alone or in combination of two or more. 5-40 weight part is preferable with respect to 100 weight part of PVA (alpha), and, as for content of a hydrazide compound, 15-25 weight part is more preferable.

The protective layer preferably contains a filler. The filler is not particularly limited and can be appropriately selected from known materials according to the purpose. For example, calcium carbonate, zinc oxide, aluminum oxide, titanium dioxide, silica, aluminum hydroxide, barium sulfate, talc, kaolin, Examples thereof include inorganic pigments such as alumina, clay and alkaline silicic acids, or known organic pigments. Among these, in consideration of matching with the thermal head (deposition adhesion) and the like, basic hydroxides such as aluminum hydroxide and calcium carbonate are preferable. Furthermore, aluminum hydroxide is particularly preferable in consideration of pH control due to moderate water solubility.
In view of water resistance (water peeling resistance), silica, kaolin and alumina which are acidic pigments (showing acidity in an aqueous solution) are preferable, and silica is particularly preferable from the viewpoint of color density.
The method for forming the protective layer is not particularly limited, and a generally known method can be adopted. For example, a protective layer coating solution may be prepared by a conventional method and coated on the heat-sensitive recording layer. There is no restriction | limiting in particular in the thickness of a protective layer, Although it can select suitably according to the objective, 1.0-7.0 micrometers is preferable.

If necessary, an intermediate layer or the like can be further provided between the support and the heat-sensitive recording layer. As components constituting these layers, pigments containing the above hollow particles, binders, thermofusible substances, surfactants, and the like can be used.

The heat-sensitive adhesive material of the present invention may be cut and used before or after thermal activation (heating) of the heat-sensitive adhesive layer. Therefore, it is preferable to form a cut in the heat-sensitive adhesive material in advance because the heat-sensitive adhesive material can be suitably used for various uses such as labels and tags.
There is no restriction | limiting in particular in the shape of the heat-sensitive adhesive material of this invention, A label form, a sheet form, a label sheet form, a roll form etc. are mentioned. Among these, a roll shape wound around a cylindrical core material is particularly preferable from the viewpoint of convenience, storage location, and handleability.
There is no restriction | limiting in particular in the adherend to which the heat-sensitive adhesive material of this invention is stuck, A magnitude | size, a shape, a structure, a material, etc. can be suitably selected according to the objective. Examples of the material include resin plates such as polyolefin (eg, polyethylene, polypropylene, etc.), acrylic, polyethylene terephthalate (PET), polystyrene, nylon, etc .; metal plates such as SUS and aluminum; paper products such as envelopes and cardboard; Wraps: Polyvinyl chloride wraps, polyethylene non-woven fabrics (envelopes, etc.) and the like.
The method for thermally activating the heat-sensitive adhesive layer of the heat-sensitive adhesive material of the present invention is not particularly limited and may be appropriately selected depending on the intended purpose. For example, an activation method using hot air or a hot roll is used. Examples include an activation method and an activation method using a thermal head. Among these, the thermal head activation method uses the existing thermal recording printer device to heat both sides of the thermal adhesive material, thereby recording on the thermal recording layer and thermal activation of the thermal adhesive layer. Are particularly preferred because they can be carried out simultaneously.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. In addition, all the parts and% shown below are based on weight.
Example 1
<Preparation of hollow particles [A]>
Dissolve 55 g of sodium chloride in 160 g of ion-exchanged water, add 1.0 g of adipic acid-diethanolamine condensate and 25 g of colloidal silica 20% aqueous solution, adjust the pH from 3.8 to 4.2 with sulfuric acid, and uniformly Mix to make the aqueous phase. 45 g of acrylonitrile, 16 g of methacrylonitrile, 5 g of N-methylolacrylamide, 23 g of isobornyl methacrylate, 0.1 g of ethylene glycol dimethacrylate, 0.3 g of azobisisobutyronitrile, 1,1-azobis (cyclohexane-1-carbonitrile 0.1 g and 15 g of isobutane are mixed, stirred and dissolved to obtain an oil phase, which is mixed with an aqueous phase and an oil phase, and stirred with a homomixer at 4000 rpm for 1 minute to form a suspension. After transferring to a bull flask and purging with nitrogen, the mixture is reacted with stirring at 70 ° C. for 6 hours and then at 90 ° C. for 14 hours.
After the reaction, it is cooled and filtered to obtain capsule particles. Next, this was foamed by heating to form hollow particles [A]. The hollow ratio of the hollow particles was 89%, and the particle diameter (median diameter) was 4.5 μm.
<Preparation example of self-crosslinking acrylic resin>
Water 170 parts Emulsifier 2.5 parts (ELYONOL ES-70 manufactured by Sanyo Chemical Industries)
Potassium persulfate 0.5 part Monomer mixture 100 parts Polymerization was carried out at 70 ° C for 9 hours while stirring the mixture having the above composition. The copolymer is adjusted to pH 7-9 with an aqueous sodium hydroxide solution, unreacted monomers and the like are removed by steam distillation, water is added to adjust the nonvolatile content, and the copolymer has a nonvolatile content of 50%. An emulsion was obtained. At this time, the monomer mixture had a ratio of 0.9 mol of 2-ethylhexyl acrylate, 0.02 mol of acrylic acid, 0.02 mol of styrene, 0.03 mol of N-methylolacrylamide, and 0.03 mol of 2-hydroxyethyl methacrylate. It was.

<Preparation of hollow underlayer coating solution [Liquid B]>
The following mixture was stirred and dispersed to prepare a hollow under layer coating solution [B solution].
Aqueous dispersion of hollow particles [A] (non-volatile content: 30%) 30 parts Acrylic ester copolymer (non-volatile content: 60%) 20 parts (7000R manufactured by Nissin Chemical Industry Co., Ltd., Tg: -70 ° C.)
Self-crosslinking acrylic resin 5 parts Polyvinyl alcohol aqueous solution 9 parts (Kuraray PVA117, nonvolatile content 16%)
Water 58 parts The above mixture was stirred and dispersed to prepare a hollow underlayer coating solution [Liquid B].

<Preparation of Solid Plasticizer Dispersion [Liquid C]>
Triphenylphosphine 10 parts 2- (3'-t-butyl-5'-methyl-2'-hydroxyphenyl)
-5-chlorobenzotriazole 20 parts 30% polyvinyl alcohol solution (L-3266 manufactured by Nippon Synthetic Chemical Co., Ltd.) 5 parts Silica (P-527 manufactured by Mizusawa Chemical Co., Ltd.) 3 parts Surfactant (alkyl = allyl sulfonate) 0.1 part Water 70 parts A mixture having the above composition was dispersed using a sand mill so that the average particle diameter was 1 µm to obtain a dispersion [liquid C].

<Adjustment of heat-sensitive adhesive layer-forming liquid [D liquid]>
Liquid C (solid plasticizer dispersion) 66 parts Acrylic ester copolymer (nonvolatile content 60%) 10 parts (Nisshin Chemical Industries, Ltd. 7000R, Tg: -70 ° C.)
Special rosin ester emulsion 6 parts (Arakawa Chemical Industries Super Ester E-650, 50% nonvolatile content)
True spherical silicone resin fine particles 3 parts (Tospearl 120 manufactured by Momentive Performance Materials)
Water 15 parts The above composition was sufficiently stirred to obtain a heat-sensitive adhesive layered solution [Liquid D].
On the surface of the base paper having an average basis weight of 80 g / m ² , the hollow under layer coating solution [B solution] was applied so as to have a mass of 4 g / m ² after drying and dried to form an intermediate layer. Next, a heat-sensitive adhesive liquid [D liquid] was applied thereon so that the mass after drying was 15 g / m ² and dried to produce the heat-sensitive adhesive material of Example 1.

Example 2
A heat-sensitive adhesive layer was formed in the same manner as in Example 1 except that the acrylic ester copolymer and the self-crosslinking acrylic resin were 23 parts and 2 parts, respectively, to prepare a heat-sensitive adhesive material.
Example 3
A heat-sensitive adhesive layer was formed in the same manner as in Example 1 except that 21 parts and 4 parts, respectively, of the acrylic ester copolymer and the self-crosslinking acrylic resin were used to prepare a heat-sensitive adhesive material.
Example 4
A heat-sensitive adhesive layer was formed in the same manner as in Example 1 except that the acrylic ester copolymer and the self-crosslinking acrylic resin were 12 parts and 13 parts, respectively, to prepare a heat-sensitive adhesive material.
Example 5
A heat-sensitive adhesive layer was formed in the same manner as in Example 1 except that the acrylic ester copolymer and the self-crosslinking acrylic resin were 10 parts and 15 parts, respectively, to prepare a heat-sensitive adhesive material.
Example 6
A heat-sensitive adhesive layer was formed in the same manner as in Example 1 except that all of the acrylic ester copolymer was replaced with a self-crosslinking acrylic resin, and a heat-sensitive adhesive material was produced.

<< Comparative Example 1 >>
A heat-sensitive adhesive layer was formed in the same manner as in Example 1 except that the self-crosslinking acrylic resin was not added and 25 parts of the acrylate copolymer was used to prepare a heat-sensitive adhesive material.
<< Comparative Example 2 >>
90% by weight carboxymethylcellulose aqueous solution 90 parts Surfactant alkyl-allylsulfonate 0.15 parts Water 9.85 parts Crosslinked resin layer forming liquid 1 (A liquid), and
A crosslinked resin layer forming liquid 2 (Liquid B) consisting of 10 parts by weight of a 10% by weight calcium chloride aqueous solution, 20 parts of a surfactant, alkyl-allyl sulfonate, 0.15 part, and 80.85 parts of water was prepared. On the surface of the base paper having an average basis weight of 80 g / m ² , the liquid A was applied and dried so that the adhesion amount after drying was 10 g / m ^2, and the adhesion amount after drying the B liquid was 1 g. / M ² was applied and dried to form a crosslinked resin layer. Subsequently, [D liquid] of Example 1 was applied so that the mass after drying was 15 g / m ² and dried to prepare a heat-sensitive adhesive material.
<< Comparative Example 3 >>
After the hollow underlayer coating solution [B solution] was dried and coated so as to have a mass of 4 g / m ² and dried to form an intermediate layer, a water-soluble melamine resin (solid content 15%) was added to [D solution]. ) Was added in an additional amount, and the heat-sensitive adhesive liquid sufficiently stirred was continuously applied so that the mass after drying was 15 g / m ² and dried to prepare a heat-sensitive adhesive material.
<< Comparative Example 4 >>
25 parts of ethylene-vinyl acetate copolymer (EVA; ethylene content 72% by weight, melting point 62 ° C., MFR 400 g / 10 min)
Tackifier 8 parts (terpene resin, manufactured by Yasuhara Chemical Co., Ltd., trade name “YS Polystar T115”)
Solid plasticizer (dicyclohexyl phthalate) 67 parts Water 67 parts A mixture of the above composition was dispersed using a sand mill to obtain a dispersion [(C-X) liquid].
Mixed dispersion [(C-X) liquid] 100 parts Aliphatic urethane resin 15 parts (Nippon Chemical Industry Co., Ltd., trade name “FW413”, weight average molecular weight: about 100,000
MFT: 0 ° C., Tg: 30 ° C., solid content 33%)

The mixture composed of the above was sufficiently stirred to obtain a heat-sensitive adhesive layered solution [(DX) solution]. This [(DX) liquid] was continuously applied to the surface of the base paper having an average basis weight of 80 g / m ² so that the mass after drying was 15 g / m ² and dried to prepare a heat-sensitive adhesive material. .

<Evaluation of adhesive properties>
Each obtained heat-sensitive adhesive material was cut into a 40 mm × 100 mm rectangle, and using a heat-sensitive printing device (manufactured by Okura Electric Co., Ltd., TH-PMD), head conditions: energy 0.40 mJ / dot, printing speed: 6 ms. / Line, platen pressure: The heat-sensitive adhesive material was thermally activated under the conditions of 6 kgf / line. The activated sample was immediately pasted on a polypropylene plate (according to the measurement method of 180 degree peeling adhesion test described in JIS Z 0237, reciprocated twice at a speed of 20 mm / s with a 2 kg rubber roller. Crimp). It was stored for 24 hours and then peeled off under the conditions of a peeling angle of 180 degrees and a peeling speed of 300 mm / min, and the adhesive force at that time was measured with a force gauge (DPS-5 manufactured by Imada). Data were read and averaged at 0.1 second intervals. The unit is N / 40 mm.
Adhesion rank is
: 25N / 40mm or more
○: 20N / 40mm or more and less than 25N / 40mm
Δ: 3N / 40mm or more and less than 20N / 40mm
X: Less than 3 N / 40 mm.

<Evaluation of adhesive residue>
After peeling the label in the adhesive property evaluation, the polypropylene plate side was observed. This operation was repeated 5 times on the same surface.
A: There is no adhesive residue on the surface.
○: A point-like transcript is slightly visible.
Δ: A dot-like transfer is visible on the entire surface.
X: The label side layer is peeled and transferred.
Alternatively, the label is torn and remains on the adherend side.
The following table summarizes the evaluation results.

  Represented in food containers such as fresh vegetables and daily foods, polypropylene containers and cardboard (pradan) used for transporting apparel, etc., or folding-type placon (oricon) with good space saving when not in use A heat-sensitive adhesive material and a heat-sensitive adhesive sheet suitable for a label to be attached to the surface of such a returnable logistics product.

JP-A-5-127598 JP 7-121108 A JP-A-7-164750 JP-A-60-45132 JP-A-6-263128 Japanese Patent Laid-Open No. 11-79152 JP-A-11-65451 Special No. 4278704 JP 2007-171239 A JP 2007-076252 A JP 2003-055624 A

"Adhesion Handbook" 12th edition, pp. 131-135, published in 1970

Claims (5)

On a support, the middle air under layer, then a thermoplastic resin, a solid plasticizer, and the heat-sensitive adhesive material obtained by sequentially applying the heat-sensitive adhesive layer comprising a tackifier, the hollow under layer hollow particles and heat A heat-sensitive adhesive material comprising a plastic resin and a self-crosslinking acrylic resin. The heat-sensitive adhesive material according to claim 1, wherein adhesiveness is exhibited by heating with a thermal head. The heat-sensitive adhesive sheet using the heat-sensitive adhesive material according to claim 1 or 2 , further comprising a recording layer on the side opposite to the surface having the heat-sensitive adhesive layer of the support. The recording layer is any one of a heat-sensitive recording layer, a thermal-melt transfer recording ink-receiving layer, an electrophotographic toner image-receiving layer, a silver halide photographic recording layer, and an ink-jet ink image-receiving layer. 3. The heat-sensitive adhesive sheet according to 3. The heat-sensitive adhesive sheet according to claim 3 or 4 , wherein a synthetic paper or a plastic film is used as the substrate.