JP5058639B2 - Heat sensitive adhesive material - Google Patents

Description

  The present invention relates to a heat-sensitive adhesive material.

Known documents relating to the heat-sensitive adhesive material have no spare time, but Patent Document 1 relating to the prior application of the present applicant is cited as the closest to the present invention.
In this document, an adhesive under layer mainly composed of a thermoplastic resin having a Tg of −70 ° C. to −10 ° C., a thermoplastic resin having a Tg of −70 ° C. to −5 ° C. and a plastic spherical hollow are provided on one side of the support. An invention relating to a heat-sensitive adhesive label sheet in which an intermediate layer mainly composed of particles and a heat-sensitive adhesive layer mainly composed of a thermoplastic resin, a tackifier, and a heat-meltable substance are sequentially provided is disclosed. This structure is excellent in adhesion to rough surface adherends such as corrugated cardboard and polyolefin wrap, and has the effect that there is no decrease in adhesion over time, but the adhesion in a low temperature (0 ° C.) environment is improved. There is a problem of reduction (see Comparative Example 2 described later).
In addition, in Japanese Patent Application No. 2006-207472 according to the prior application of the present applicant, by incorporating triphenylphosphine as a heat-meltable substance in the heat-sensitive adhesive layer, the adhesive strength at low temperature (0 ° C.) is strong, The heat-sensitive adhesive material having a strong adhesive strength over time in a room temperature (23 ° C.) or high temperature (40 ° C.) environment has been disclosed. There is a problem that the adhesive strength is low. Furthermore, since the delay property is short and the adhesiveness is high when heated, the time during which the adhesive strength is maintained after the heating is short, so that there is a problem that it is difficult to use like a normal pressure-sensitive label (Comparative Example 1 described later). reference).
The use of triphenylphosphine as a heat-sensitive adhesive material is known as seen in Patent Document 2 and the like, but the adhesive force on a rough surface adherend in a wide temperature range from room temperature to high temperature is known. As far as the present inventors are aware, there is no literature that mentions the relationship between securing and improving the delay.
In short, the fact is that a heat-sensitive adhesive material having comprehensively excellent characteristics with respect to a rough adherend has not been realized yet.

JP 2006-83196 A JP 2000-103969 A

  The present invention has good adhesiveness over a wide temperature range from low temperature (0 ° C.) to high temperature (40 ° C.), and also has good blocking resistance and delay resistance, even on rough surface adherends such as cardboard. An object is to provide a heat-sensitive adhesive material.

〔上記一般式（１）中、Ｒ^１とＲ^２は、互いに同一であって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、及びハロゲン原子の何れかを表す。〕
３） 熱溶融性物質中のトリフェニルホスフィンの含有量が６０〜８０重量％であることを特徴とする１）又は２）記載の感熱性粘着材料。
４） 感熱性粘着剤層の乾燥付着量が５〜１５ｇ／ｍ^２であることを特徴とする１）〜３）の何れかに記載の感熱性粘着材料。
５） 中間層のプラスチック球状中空粒子は、中空率が７０％以上、最大粒子径が１０．０μｍ以下、体積平均粒子径が２．０〜５．０μｍであることを特徴とする１）〜４）の何れかに記載の感熱性粘着材料。
６） 支持体の感熱性粘着剤層を有しない側の面上に少なくとも感熱記録層を有し、かつ該感熱記録層が少なくともロイコ染料と顕色剤とバインダー樹脂を含有することを特徴とする１）〜５）の何れかに記載の感熱性粘着材料。
７） その形状が、ラベル状、シート状、ラベルシート状、及びロール状の何れかであることを特徴とする１）〜６）の何れかに記載の感熱性粘着材料。 The above-mentioned problems are solved by the following inventions 1) to 7 ).
1) On one surface of the support, an adhesive under layer mainly composed of a thermoplastic resin of at least Tg-70 ° C to -10 ° C, an intermediate layer mainly composed of a thermoplastic resin and plastic spherical hollow particles, heat sensitive The heat-sensitive pressure-sensitive adhesive layer contains a thermoplastic resin, a tackifier and a heat-meltable substance, and contains at least triphenylphosphine as the heat-meltable substance , The thermoplastic resin of the intermediate layer is an acrylic ester copolymer, a methacrylic ester copolymer, an acrylic ester-methacrylic ester copolymer, an acrylic ester-styrene copolymer, an acrylic ester-methacrylic ester. A heat-sensitive adhesive material, which is at least one selected from a styrene copolymer and an ethylene-vinyl acetate copolymer .
2) The heat-sensitive adhesive material according to 1), which further contains a benzotriazole compound represented by the following general formula (1) as a heat-meltable substance.

[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 either a hydrogen atom or a halogen atom. ]
3) The heat-sensitive adhesive material according to 1) or 2), wherein the content of triphenylphosphine in the hot-melt material is 60 to 80% by weight.
4) The heat-sensitive adhesive material according to any one of 1) to 3), wherein the dry adhesion amount of the heat-sensitive adhesive layer is 5 to 15 g / m ² .
5) Plastic spherical hollow particles of the intermediate layer, the hollow of 70% or more, a maximum particle size of 10.0μm or less, 1, wherein the volume average particle diameter of 2.0~5.0μm) ~ 4 The heat-sensitive adhesive material according to any one of 1).
6 ) It has at least a heat-sensitive recording layer on the surface of the support which does not have a heat-sensitive adhesive layer, and the heat-sensitive recording layer contains at least a leuco dye, a developer and a binder resin. The heat-sensitive adhesive material according to any one of 1) to 5 ).
7 ) The heat-sensitive adhesive material according to any one of 1) to 6 ), wherein the shape is any one of a label shape, a sheet shape, a label sheet shape, and a roll shape.

Hereinafter, the present invention will be described in detail.
The heat-sensitive adhesive material of the present invention is mainly composed of an adhesive under layer mainly composed of a thermoplastic resin of at least Tg-70 ° C to -10 ° C, thermoplastic resin and plastic spherical hollow particles on one surface of the support. And an intermediate layer and a heat-sensitive adhesive layer. The heat-sensitive adhesive layer contains a thermoplastic resin, a tackifier, and a hot-melt material, and the hot-melt material contains at least triphenylphosphine.
Each element which comprises the said thermosensitive adhesive material is demonstrated in order.

<Support>
The shape, structure, size and the like of the support are not particularly limited and can be appropriately selected according to the purpose. Examples of the shape include a flat plate shape, and the structure is a single layer structure. Alternatively, a laminated structure may be used, and the size can be appropriately selected according to the size of the heat-sensitive adhesive material.
The material for the support is not particularly limited and may be appropriately selected depending on the intended purpose. Examples of the inorganic material include glass, quartz, silicon, silicon oxide, aluminum oxide, SiO ₂ and metal. . Examples of organic materials include paper such as fine paper, art paper, coated paper, and synthetic paper; cellulose derivatives such as cellulose triacetate; polyester resins such as polyethylene terephthalate (PET) and polybutylene terephthalate; polycarbonate, polystyrene, and polymethyl Examples thereof include polyolefins such as methacrylate, polyamide, polyethylene, and polypropylene. Among these, fine paper, coated paper, plastic film, and synthetic paper are particularly preferable.
The support is preferably subjected to surface modification such as corona discharge treatment, oxidation reaction treatment (chromic acid, etc.), etching treatment, easy adhesion treatment, antistatic treatment, etc. for the purpose of improving the adhesion of the coating layer. Further, it is preferable to add a white pigment such as titanium oxide to the support.
There is no restriction | limiting in particular in the thickness of a support body, Although it can select suitably according to the objective, 50-2,000 micrometers is preferable and 100-1,000 micrometers is more preferable.

<Adhesive under layer>
The thermoplastic resin having a Tg of −70 ° C. to −10 ° C. used for the adhesive under layer is preferably a thermoplastic resin used for a heat-sensitive adhesive layer or an intermediate layer, and a natural rubber latex obtained by graft copolymerization with a vinyl monomer, Acrylic ester copolymer, methacrylic ester copolymer, acrylic ester-methacrylic ester copolymer, acrylic ester-styrene copolymer, acrylic ester-methacrylic ester-styrene copolymer, ethylene-acetic acid Examples thereof include at least one kind or a mixture of two or more kinds selected from vinyl copolymers.
In the case of a high Tg resin exceeding the Tg range of the thermoplastic resin used for the adhesive under layer and the intermediate layer, the characteristics of the adhesive under layer and the intermediate layer cannot be obtained at all, and rough surface adherends such as cardboard and polyolefin Adhesive strength with respect to wrapping or the like is weak, and the adhesive strength of only the heat-sensitive adhesive layer provided in the upper layer is obtained. On the other hand, most of the resins have a Tg of −70 ° C. or higher, and there is no particular problem even in the case of a low Tg resin that is out of the Tg range of the thermoplastic resin of the present invention.
The coating amount of the adhesive under layer is generally 2~35g / ^{m 2} on a dry coating amount is preferably in the range of 4~25g / ^{m 2.} When the coating amount is less than 2 g / m ² , sufficient adhesion cannot be obtained when bonding is performed after thermal activation. On the other hand, if it exceeds 35 g / m ² , the adhesive strength and the heat insulating effect are saturated, which is not economical.

<Intermediate layer>
The intermediate layer contains at least a thermoplastic resin and plastic spherical hollow particles, and further contains other components as necessary.
-Thermoplastic resin-
As the thermoplastic resin used in the intermediate layer, the thermoplastic resin preferably used in the heat-sensitive adhesive layer, an acrylic acid ester copolymer, a methacrylic acid ester copolymers, acrylic acid ester - methacrylic acid ester copolymer, acrylate - styrene copolymer, an acrylic acid ester - methacrylic acid ester - styrene copolymer, ethylene - Ru using at least one selected from vinyl acetate copolymer.

-Plastic spherical hollow particles-
Plastic spherical hollow particles are plastic spherical hollows having a volume average particle diameter of 2.0 to 5.0 μm and a hollow ratio of 70% or more having a heat insulating effect in consideration of the problem of low energy thermal activation (high sensitivity thermal activation). Particles are preferred. More preferably, the maximum particle size is 10.0 μm or less, the volume average particle size is 2.0 to 5.0 μm, and the hollowness is 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.
When the volume average particle diameter is larger than 5.0 μm, when the heat-sensitive adhesive layer is provided on the intermediate layer using these, a portion where the heat-sensitive adhesive layer is not formed can be formed in a portion where there are large particles. When activated, the adhesive strength tends to decrease. On the other hand, if 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.
The plastic spherical hollow particle means a hollow particle that is already foamed with a thermoplastic resin as a shell and containing air or other gas inside. Moreover, the hollow ratio here is the ratio of the volume of the internal void portion to the entire volume of the hollow particles.
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 plastic spherical hollow particles satisfying the above conditions, an acrylonitrile-vinylidene chloride-methyl methacrylate copolymer or an acrylonitrile-methacrylonitrile-isobornyl methacrylate copolymer is preferable.
About the ratio of the thermoplastic resin used for an intermediate | middle layer, and a plastic spherical hollow particle, 0.1-1.0 weight part of plastic spherical hollow particles are preferable with respect to 1 weight part of resin, and a plastic spherical hollow particle is 0.1 weight. If it is less than the part, it is inferior to high-sensitivity thermal activation, and further the blocking resistance is lowered. On the contrary, when the plastic spherical hollow particles are more than 1.0 parts by weight, the adhesive strength to rough surface adherends such as corrugated cardboard and polyolefin wrap is reduced, and it depends on only the adhesive strength of the heat-sensitive adhesive layer provided in the upper layer. It will be.
The coating amount of the intermediate layer is usually 0.2~8g / ^{m 2} on a dry coating amount is preferably in the range of 1 to 5 g / ^{m 2.} When the coating amount is less than 0.2 g / m ² , the heat insulation effect at the time of thermal activation cannot be obtained. ^{On the other hand} , if it exceeds 8 g / m ² , the adhesive force and the heat insulating effect are saturated, and the effect of improving the adhesive force from the adhesive under layer is reduced, which is not preferable.

<Thermosensitive adhesive layer>
The heat-sensitive adhesive layer contains at least a thermoplastic resin, a tackifier, and a hot-melt material, and further contains other components as necessary.
-Hot-melting substance-
The heat-meltable substance is solid at room temperature, so it does not give plasticity to the resin. However, it melts by heating, swells or softens the resin, expresses adhesiveness, melts by heating, and then slowly crystallizes. Therefore, it is a substance that can maintain the adhesiveness for a long time even after the heat source is removed.
As the heat-meltable substance, triphenylphosphine is essential, and other heat-meltable substances are preferably used in combination.
When triphenylphosphine is contained in the heat-sensitive adhesive layer, it is considered that the heat-sensitive adhesive layer can form a very soft state when heated, and can form a soft state at low temperatures (0 ° C). The resin component that contributes to the adhesion of the intermediate layer and the adhesive under layer by forming a soft state at room temperature (23 ° C.) and high temperature (40 ° C.). I think it can be used effectively.
Furthermore, by making effective use of the resin component that contributes to the adhesion of the intermediate layer and the adhesive under layer by forming a soft state, it becomes possible to maintain the adhesiveness for a long time even after removing the heat source, and the delay property Thinks that will improve

Triphenylphosphine is an organic phosphorus compound represented by the following structural formula (2), and may be abbreviated as TPP. It is relatively stable to air, is a crystalline solid at room temperature, and is soluble in nonpolar organic solvents such as benzene. The molecular weight is 262.3 and the melting point is 79-81 ° C.

〔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、及びハロゲン原子の何れかを表す。〕
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。
前記置換基としては、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。
前記ハロゲン原子としては、例えば、フッ素原子、塩素原子、臭素原子、ヨウ素原子などが挙げられる。 Examples of heat-meltable substances other than triphenylphosphine are benzotriazole compounds represented by the following general formula (1), hydroxybenzoic acid ester compounds represented by the following general formula (3), and the following general formula (4). A compound represented by the following general formula (5), a compound represented by the following general formula (6), and the like. Among these, a benzotriazole compound represented by the following general formula (1) is particularly preferable.

[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 either 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. Is 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 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^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。〕

[In the general formula (3), 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 (3), 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 the alkenyl group in the general formula (3), those having 2 to 8 carbon atoms are suitable, for example, vinyl group, allyl group, 1-propenyl group, methacryl group, 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 (3), 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 (3) include a phenyl group, a naphthyl group, an anthranyl group, a fluorenyl group, a phenalenyl group, a phenanthrenyl 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 (3) 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（４）中、Ｒ^４とＲ^５は、互いに同一であってもよいし異なっていてもよく、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、及び水酸基の何れかを表す。〕

[In the general formula (4), R ⁴ and R ⁵ may be the same or different from each other, and represent either an alkyl group or an alkoxy group. Y represents either a hydrogen atom or a hydroxyl group. ]

〔上記一般式（５）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、及び水酸基の何れかを表す。〕

[In General Formula (5), R ⁶ represents any one of a hydrogen atom, a halogen atom, an alkyl group, and an alkoxy group. Y represents either a hydrogen atom or a hydroxyl group. ]

〔上記一般式（６）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。〕

[In the general formula (6), R ⁷ represents any one of a hydrogen atom, a halogen atom, an alkyl group, and an alkoxy group. ]

In the general formulas (4) to (6), 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 (4) 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 (5) 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 (6) 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.

The compounds represented by the general formulas (1) and (3) to (6) are preferably used which are solid at room temperature and melt upon heating. The melting point of these compounds is preferably 70 ° C. or higher, more preferably 80 ° C. or higher, and the upper limit is preferably about 200 ° C.
When the melting point is less than 70 ° C., when it is used as a heat-sensitive adhesive, a storage defect (blocking) may occur, such as an adhesive force appearing at a normal storage environment temperature. In addition, there may be a problem in production such as an adhesive force being developed when the heat-sensitive adhesive coating solution is applied on a support and dried. On the other hand, if the melting point exceeds 200 ° C., a large amount of energy is required to develop the adhesive force, which may cause practical problems. In addition, when a thermal recording paper is used as a support and an adhesive force is developed with a large amount of energy, there is a problem that a printed image cannot be read because the thermal recording layer is colored.
In addition, by setting the volume average particle diameter of the heat-meltable substance represented by the general formulas (1) and (3) to (6) to 0.5 μm or less, dynamic thermal sensitivity is improved, and heat is generated with low energy. It becomes a heat-activated pressure-sensitive adhesive by being compatible with the plastic resin and the tackifier. Furthermore, by making it 0.5 μm or less, the storage stability at a normal storage environment temperature is improved (blocking resistance is improved).

The total content in the heat-sensitive adhesive layer of triphenylphosphine, which is a heat-melting substance, and the compounds represented by the general formulas (1) and (3) to (6) is preferably 25 to 80% by weight. Weight percent is more preferred. When the total content is less than 25% by weight, when combined with a thermoplastic resin, storage problems such as adhesive strength appearing under normal storage environment temperature (blocking) may occur, or adhesive strength may decrease. In some cases, if it exceeds 80% by weight, the adhesive strength may be lowered.
The content of triphenylphosphine in the hot-melt material is preferably 50% by weight or more, and more preferably 60 to 80% by weight. When the content is less than 60% by weight, the adhesive strength under a low temperature environment of 0 ° C. to 10 ° C. may be insufficient, and when it exceeds 80% by weight, the blocking resistance may be lowered.

-Thermoplastic resin-
The thermoplastic resin is not particularly limited and may be appropriately selected depending on the intended purpose. However, when a resin similar to the thermoplastic resin used for the adhesive under layer and the intermediate layer is used, the phase difference between the resins in both layers is obtained. Since solubility improves, since the adhesive force with respect to rough surface adherends, such as a corrugated cardboard, improves, it is preferable.
Examples of the thermoplastic resin include natural rubber latex obtained by graft copolymerization with a vinyl monomer, acrylic ester copolymer, methacrylic ester copolymer, acrylic ester-methacrylic ester copolymer, acrylic ester-styrene. A copolymer, an acrylic ester-methacrylic ester-styrene copolymer, an ethylene-vinyl acetate copolymer, etc. are mentioned.
These may be used individually by 1 type and may use 2 or more types together.
The content of the thermoplastic resin in the heat-sensitive adhesive layer is preferably 10 to 60% by weight, and more preferably 15 to 50% by weight. When the content is less than 10% by weight or more than 60% by weight, both of them are not preferable because the adhesive strength is lowered. On the other hand, if the content of the resin having a low Tg exceeds 60% by weight, there may be a storage defect (blocking) such as an adhesive force developed at a normal storage environment temperature.

-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, a rosin derivative (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 melting point (or softening point) of the tackifier is preferably 80 ° C. or higher, and more preferably 80 to 200 ° C. If the melting point (or softening point) is less than 80 ° C., storage defects (decrease in blocking resistance) may occur at normal storage environment temperatures.
1-30 weight% is preferable and, as for content of the tackifier in a heat-sensitive adhesive layer, 1-20 weight% is more preferable. If the content is less than 1% by weight, the adhesive strength may be remarkably reduced. If the content exceeds 30% by weight, storage troubles (decrease in blocking resistance) at normal storage environment temperatures and low temperature environments may occur. Decrease in initial adhesive strength may occur.

In addition to the above components, the heat-sensitive adhesive layer has an inorganic substance such as titanium oxide, alumina, colloidal silica, kaolin, and talc to prevent blocking; stearic acid metal salt, paraffin, natural wax, synthetic wax, natural fat and oil, Organic substances such as polystyrene powder can be added, and other components such as a eutectic agent, a dispersant, an antifoaming agent, and a thickener can be added as necessary.
The dry application amount of the heat-sensitive adhesive layer coating solution (the dry adhesion amount of the heat-sensitive adhesive layer) is preferably 5 to 15 g / m ² . If the coating amount is less than 5 g / m ² , sufficient adhesive strength may not be obtained when pasting at a low temperature. If the coating amount exceeds 15 g / m ² , the heat insulating effect of the under layer is weakened or pasting at a high temperature. In such a case, sufficient adhesive strength may not be obtained.

There is no restriction | limiting in particular in the formation method of an adhesion under layer, an intermediate | middle layer, and 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 does not melt | dissolve the hot-meltable substance to be used. 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.

Next, the heat-sensitive adhesive material of the present invention preferably has at least a heat-sensitive recording layer on the side of the support that does not have the heat-sensitive adhesive layer, and includes a protective layer, an intermediate layer, and other if necessary It has a layer of.
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, Indoline phthalide dyes are listed.

  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 The 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 said 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 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 In addition to water-soluble polymers such as maleic acid copolymer alkali salts, polyacrylamide, sodium alginate, gelatin, casein, polyvinyl acetate, polyurethane, polyacrylic acid, polyacrylic acid Tellurium, polymethacrylic acid ester, polybutyl methacrylate, vinyl chloride-vinyl acetate copolymer, ethylene-vinyl acetate copolymer, etc. emulsion; styrene-butadiene copolymer, latex such as styrene-butadiene-acrylic copolymer And the like.
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 provided together with a binder resin and other components, a ball mill, an attritor, and the like. After pulverizing and dispersing with a disperser such as a sand mill until the dispersed particle size becomes 1 to 3 μm, the mixture is mixed with a filler, a heat-fusible substance (sensitizer) dispersion liquid, etc., if necessary, in a predetermined formulation. A thermal 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.

-Protective layer-
The protective layer is preferably a material containing polyvinyl alcohol (PVAα) having a reactive carbonyl group and a hydrazide compound, and further containing other components as necessary.
A protective layer containing PVAα and a hydrazide compound as a cross-linking 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, but a vinyl monomer having a diacetone group is preferable, and specific examples include diacetone acrylamide and meta diacetone acrylamide. It is done. 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 in the range of 2 to 10 mol% in view of water resistance. If the content is less than 2 mol%, the practical water resistance is insufficient, and if it exceeds 10 mol%, no further improvement in water resistance is observed and the cost increases, 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 dihydric acid dihydrazide Examples thereof include isophthalic 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 individually by 1 type and may use 2 or more types together.
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 (different from the intermediate layer having hollow particles) may be provided between the support and the heat-sensitive recording layer.
As the component constituting the intermediate layer, the aforementioned filler, binder resin, heat fusible substance, surfactant 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 are no particular restrictions on the adherend to which the heat-sensitive adhesive material of the present invention is applied, and the size, shape, structure, material, etc. can be appropriately selected according to the purpose. (For example, polyethylene, polypropylene, etc.), resin plates such as acrylic, polyethylene terephthalate (PET), polystyrene, nylon, etc .; metal plates, such as SUS, aluminum; paper products such as envelopes, cardboard, etc .; polyolefin wraps; Wraps, polyethylene nonwoven fabrics (envelopes, etc.) and the like.
In particular, the heat-sensitive adhesive material of the present invention has a great feature in that it has a strong adhesive force to rough adherends such as corrugated cardboard as compared to conventional ones, and can be firmly attached. It is advantageous to use it.
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.

  According to the present invention, even a rough surface adherend such as cardboard has good adhesiveness in a wide temperature range from low temperature (0 ° C.) to high temperature (40 ° C.), and also has blocking resistance and delay properties. A good heat-sensitive adhesive material can be provided.

  EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated further more concretely, this invention is not limited at all by these Examples. Unless otherwise specified, “parts”, “%”, and “average molecular weight” are “parts by weight”, “% by weight”, and “weight average molecular weight”.

[Adjustment of adhesive underlayer coating solution]
[A-1 solution]
A mixture having the following composition was stirred to prepare an adhesive undercoating solution [A-1 solution].
-Copolymer of 2-ethylhexyl acrylate / methyl methacrylate / styrene (Tg-65 ° C., average molecular weight 500,000, solid content concentration 55.4%, Showa Polymer)
... 90.3 parts Surfactant: Dapro W-77 (manufactured by Elementis Japan) ... 0.1 part Water: 9.7 parts [A-2 solution]
A mixture having the following composition was stirred to prepare an adhesive undercoating solution [A-2 solution].
・ Pressure-sensitive adhesive (BPW6111: solid content concentration 59.5%, manufactured by Toyo Ink Co., Ltd.)… 84 parts ・ Water: 16 parts [A-3 solution]
A mixture having the following composition was stirred to prepare an adhesive undercoating solution [A-3 solution].
・ Styrene / butadiene copolymer latex (Tg + 6 ° C., solid content concentration 48%,
Nippon A & L, Smartex PA-9159) ... 90.3 parts Surfactant: Dapro W-77 (made by Elementis Japan) ... 0.1 partsWater: 9.7 parts

[Adjustment of intermediate layer coating solution]
[B-1 solution]
An intermediate layer coating solution [B-1 solution] was prepared by stirring and dispersing a mixture having the following composition: Plastic spherical hollow particles [1]
(Acrylonitrile / vinylidene chloride / methyl methacrylate copolymer)
(Solid content concentration 41%, volume average particle diameter 3.6 μm, hollow rate 90%) ... 14.6 parts ・ 2-ethylhexyl acrylate / methyl methacrylate / styrene copolymer (Tg-65 ° C., average molecular weight 500,000) , Solid content concentration 55.4%, Showa Polymer)
21.7 parts Surfactant: Dapro W-77 (made by Elementis Japan) 0.1 parts Water 63.7 parts [Liquid B-2]
An intermediate layer coating solution [B-2 solution] was prepared by stirring and dispersing a mixture having the following composition: Plastic spherical hollow particles [2]
(Ropeke HP-91: solid content concentration 27.5%, volume average particle size 1.0 μm,
Hollow ratio 50%, manufactured by Rohm and Haas Japan) ... 21.67 parts-Copolymer of 2-ethylhexyl acrylate / methyl methacrylate / styrene (Tg-65 ° C, average molecular weight 500,000, solid content concentration 55. 4%, Showa Polymer)
21.7 parts Surfactant: Dapro W-77 (made by Elementis Japan) 0.1 part Water 56.55 parts [B-3 solution]
An intermediate layer coating solution [B-3 solution] was prepared by stirring and dispersing a mixture having the following composition: Plastic spherical hollow particles [3]
(Acrylonitrile / vinylidene chloride / methyl methacrylate copolymer)
(Solid content concentration 41%, volume average particle size 6.0 μm, maximum particle size 10 μm or more
14.6 parts ・ Copolymer of 2-ethylhexyl acrylate / methyl methacrylate / styrene (Tg-65 ° C., average molecular weight 500,000, solid content concentration 55.4%, Showa High) (Molecular)
21.7 parts Surfactant: Dapro W-77 (made by Elementis Japan) 0.1 parts Water 63.7 parts [B-4 solution]
An intermediate layer coating solution [B-4 solution] was prepared by stirring and dispersing a mixture having the following composition: Plastic spherical hollow particles [1]
(Acrylonitrile / vinylidene chloride / methyl methacrylate copolymer)
(Solid content concentration 41%, volume average particle size 3.6 μm, hollow rate 90%) 14.6 parts styrene / butadiene copolymer latex (Tg + 6 ° C., solid content concentration 48%,
Nippon A & L, Smartex) ... 25 parts Surfactant: Dapro W-77 (made by Elementiment Japan) ... 0.1 part Water ... 60.4 parts

[Preparation of hot melt material dispersion]
[C-1 solution]
A mixture having the following composition was dispersed using a sand mill so that the volume average particle diameter was 1.0 μm to obtain a dispersion [C-1 solution].
Triphenylphosphine [made by Hokuko Chemical Co., Ltd .: TPP] 30.0 parts Polyvinyl alcohol 10% aqueous solution (average molecular weight 15000, manufactured by Nippon Synthetic Chemical,
L-3266, saponification degree 88%) ... 15 parts Surfactant: Olfine PD-001 (manufactured by Nissin Chemical Industry) ... 0.2 parts Water ... 54.8 parts [C-2 solution]
A mixture having the following composition was dispersed using a sand mill so that the average particle size was 1.0 μm to obtain a dispersion [liquid C-2].
・ 2- (2′-hydroxy-3′-t-butyl-5′-methylphenyl) -5-chlorobenzotriazole (mp 138 ° C.) 30.0 parts ・ 10% aqueous solution of polyvinyl alcohol (average molecular weight 15000, Japan) Made by synthetic chemistry,
L-3266, saponification degree 88%) ... 15 parts Surfactant: Olfine PD-001 (manufactured by Nissin Chemical Industry) ... 0.2 parts Water ... 54.8 parts

[Preparation of heat-sensitive adhesive coating solution]
[D-1 solution]
A mixture having the following composition was uniformly mixed to prepare a heat-sensitive adhesive coating solution [D-1 solution].
-Copolymer of 2-ethylhexyl acrylate / methyl methacrylate / styrene (Tg-65 ° C., average molecular weight 500,000, solid content concentration 55.4%, Showa Polymer)
9.2 parts ・ Terpene phenol emulsion (solid content concentration = 50%, softening point = 150 ° C.,
Arakawa Chemical Co., Ltd., Tamanol E-100) ... 6.6 parts-Hot melt material dispersion (C-1 solution) ... 40.4 parts-Hot melt material dispersion (C-2 solution) ... 43.8 Part [D-2 liquid]
A mixture having the following composition was uniformly mixed to prepare a heat-sensitive adhesive coating solution [D-2 solution].
-Copolymer of 2-ethylhexyl acrylate / methyl methacrylate / styrene (Tg-65 ° C., average molecular weight 500,000, solid content concentration 55.4%, Showa Polymer)
9.2 parts ・ Terpene phenol emulsion (solid content concentration = 50%, softening point = 150 ° C.,
Arakawa Chemical Co., Ltd., Tamanol E-100) ... 6.6 parts-Hot melt material dispersion (C-1 solution) ... 82.5 parts-Hot melt material dispersion (C-2 solution) ... 1.7 Part [D-3 solution]
A mixture having the following composition was uniformly mixed to prepare a heat-sensitive adhesive coating solution [D-3 solution].
-Copolymer of 2-ethylhexyl acrylate / methyl methacrylate / styrene (Tg-65 ° C., average molecular weight 500,000, solid content concentration 55.4%, Showa Polymer)
9.2 parts ・ Terpene phenol emulsion (solid content concentration = 50%, softening point = 150 ° C.,
Arakawa Chemical Co., Ltd., Tamanol E-100) ... 6.6 parts-Hot melt material dispersion (C-1 solution) ... 63.2 parts-Hot melt material dispersion (C-2 solution) ... 21.0 Part [D-4 solution]
A mixture having the following composition was uniformly mixed to prepare a heat-sensitive adhesive coating solution [D-4 solution].
-Copolymer of 2-ethylhexyl acrylate / methyl methacrylate / styrene (Tg-65 ° C., average molecular weight 500,000, solid content concentration 55.4%, Showa Polymer)
9.2 parts ・ Terpene phenol emulsion (solid content concentration = 50%, softening point = 150 ° C.,
Arakawa Chemical Co., Ltd., Tamanol E-100) ... 6.6 parts ・ Hot-melting substance dispersion (C-2 liquid) ... 84.2 parts

[Creation of thermal recording paper]
[Liquid E] Non-foaming heat insulating layer forming coating liquid A non-foaming heat insulating layer forming coating liquid [E liquid] was prepared by stirring and dispersing a mixture having the following composition.
・ Small hollow particle dispersion (copolymer resin mainly composed of vinylidene chloride / acrylonitrile)
(Solid content 32%, volume average particle size 3.6 μm, hollow rate 92%) 30 parts ・ Styrene / butadiene copolymer latex (Tg + 4 ° C., manufactured by Nippon A & L)
... 10 parts-Surfactant: Dapro W-77 (manufactured by Elementis Japan) ... 0.1 part-Water ... 60 parts [Liquid F] color former dispersion liquid A volume average particle size of 1. [F solution] was prepared by dispersing using a sand mill so as to have a thickness of about 5 μm.
・ 3-di-n-butylamino-6-methyl-7-anilinofluorane 20 parts ・ 10% aqueous solution of polyvinyl alcohol (average molecular weight 80000) 10 parts ・ Water 70 parts [liquid G] Colorant dispersion [G liquid] was prepared by dispersing a mixture having the following composition using a sand mill so that the average particle size was about 1.5 μm.
4-isopropoxy-4'-hydroxydiphenylsulfone: 10 parts Polyvinyl alcohol 10% aqueous solution (average molecular weight 80,000) ... 25 parts Calcium carbonate (Shiraishi Kogyo Co., Ltd., CALSHITEC Brillant-15) ... 15 parts Water: 50 parts Next, the mixture [F solution]: [G solution] = 1: 8 was mixed and stirred to obtain a heat-sensitive recording layer [H solution].
Next, the [E liquid] is coated on the surface of an average basis weight of 80 g / m ² substrate so that the weight after drying is 4 g / m ^2, and a non-foaming heat insulating layer is provided thereon. After the above [Liquid H] is dried, it is applied and dried so as to have a weight of 5 g / m ² to provide a heat-sensitive recording layer, and further subjected to super-calender treatment so that the Oken smoothness becomes 2000 seconds. A layer-coated paper was obtained.

[Adjustment of protective layer coating solution]
A protective layer primary dispersion was prepared by pulverizing and dispersing a mixture having the following composition in a vertical sand mill so that the volume average particle diameter was 1 μm or less.
[Primary dispersion for protective layer]
Aluminum hydroxide: 20 parts Polyvinyl alcohol 10% aqueous solution (average molecular weight 80000): 20 parts Water: 40 parts Next, a mixture having the following composition was uniformly mixed to prepare a protective layer coating solution. .
Protective layer primary dispersion: 10 parts Polyvinyl alcohol 10% aqueous solution (average molecular weight 80000) 20 parts 12.5% epichlorohydrin aqueous solution 5 parts 30% zinc stearate dispersion 2 parts Next The protective layer coating solution was coated on a heat-sensitive color-developing layer-coated paper so that the dry coating amount was 3.0 g / m ² and dried. Then, it processed with the super calender so that the Oken type | formula smoothness might be set to 2000 second, and the thermal recording paper of the Example and the comparative example was obtained.

[Example sample preparation and evaluation]
On the surface opposite to the heat-sensitive recording layer of the heat-sensitive recording paper, the adhesive under layer coating solution (A solution) shown in Table 1 below was applied so that the dry adhesion amount was 20 g / m ^2, and then the intermediate layer was applied. The liquid (liquid B) and the heat-sensitive adhesive coating liquid (liquid D) were applied in order so as to have the dry adhesion amount shown in Table 1, and then dried, and Examples 1 to 9 and Comparative Examples 1 and 2 A heat-sensitive adhesive label sheet was obtained.

About each said heat-sensitive adhesive label sheet, adhesive force and blocking resistance were evaluated as follows.
<Adhesion measurement>
Each heat-sensitive adhesive label sheet of Examples and Comparative Examples was cut into a 40 mm × 150 mm rectangle, and using a thermal printing apparatus TH-PMD manufactured by Okura Electric Co., Ltd., head conditions: energy 0.5 mJ / dot, printing speed: 4 ms / Line, platen pressure: Heat activated under conditions of 6 kgf / line. Subsequently, it was affixed on the adherend (cardboard) in the longitudinal direction with a 2 kg pressure rubber roller, and after 10 minutes, it was peeled off under the conditions of a peeling angle of 180 degrees and a peeling speed of 300 mm / min.
The adhesive strength at that time was measured with a force gauge (MODEL DPS-5, manufactured by IMADA), and the values obtained by reading and averaging the data at 0.1 second intervals are shown in Table 2. The unit is gf / 40 mm. This test was performed in a low temperature environment (0 ° C.) and a high temperature (40 ° C.) environment.
[Evaluation criteria for adhesion to cardboard]
The evaluation criteria for adhesive strength shown in Table 2 are as follows.
A: 700 gf / 40 mm or more
○: 500 gf / 40 mm or more and less than 700 gf / 40 mm
Δ: 300 gf / 40 mm or more and less than 500 gf / 40 mm
X: Less than 300 gf / 40 mm

<Evaluation of blocking resistance>
The surface opposite to the heat-sensitive adhesive layer surface (heat-sensitive recording layer) of each heat-sensitive pressure-sensitive adhesive label sheet was brought into contact, applied with a pressure of 200 gf / cm ² , and left for 24 hours at 40 ° C. under Dry conditions. Next, after leaving at room temperature, the sample was peeled off, and the blocking resistance at that time was evaluated according to the criteria shown in Table 3 below. The ranks are divided into 10 ranks, with ranks 10 and 9 being “◎”, ranks 8 and 7 being “◯”, ranks 6, 5, and 4 being “Δ”, and ranks 3, 2, and 1 being “x”. Rank 7 or higher is a practical level. The evaluation results are shown in Table 2.
In addition, it refers to the state in which the degree of blocking becomes heavier in the order of “resistance feeling at peeling”, “peeling sound”, “spot transfer”, “peeling”, and “resistance feeling at peeling” refers to adhesiveness. It means that it sticks lightly even when it is not held, and the “self-weight” in it means a state where even if it sticks lightly, it will peel off naturally if you hold only the top two sheets of paper. Also, “peeling sound” means that a sound is produced when it is peeled from a sticky state, and “spot transfer” is a state in which the heat-sensitive adhesive layer is transferred to the back surface in a point shape. "Hagare" is a phenomenon in which the heat-sensitive adhesive layer sticks to the back surface and the heat-sensitive adhesive layer peels off or the paper on the back surface peels (breaks). Refers to that.

From the result of Table 2, Examples 1-10 have strong adhesive force in low temperature (0 degreeC) and high temperature (40 degreeC) environment with respect to corrugated cardboard compared with Comparative Examples 1-2, and blocking resistance is also favorable. I understand that there is. Further, since the heat-sensitive recording layer was provided, the heat-sensitive adhesive label sheet could be thermally activated after being recorded on the heat-sensitive recording layer and stuck on the cardboard.
In Example 1, since the content of triphenylphosphine in the hot-melt material was outside the lower limit of the preferred range, the low-temperature adhesive force was slightly reduced.
Moreover, in Example 2, since the content of triphenylphosphine in the hot-melt material was outside the upper limit of the preferred range, the high-temperature adhesive force was slightly reduced.
Moreover, in Example 3, since the dry adhesion amount of the heat-sensitive adhesive layer was outside the lower limit of the preferred range, the adhesive strength was slightly reduced.
Moreover, in Example 4, since the dry adhesion amount of the heat-sensitive adhesive layer was outside the upper limit of the preferable range, the high-temperature adhesive force was slightly reduced.
Moreover, in Example 5, since the volume average particle diameter of the plastic spherical hollow particles is out of the lower limit of the preferable range, the adhesive force is slightly lowered.
Moreover, since Example 6 includes the plastic spherical hollow particles having a maximum particle diameter of 10.0 μm or more, the adhesive force was slightly lowered and the blocking resistance was slightly lowered.
In Example 7, the Tg of the thermoplastic resin used for the intermediate layer was outside the preferred range, so the high-temperature adhesive force was slightly reduced. In Example 8, the amount of adhesion of the intermediate layer was in the preferred range. Since it was outside the upper limit, the high temperature adhesive strength was slightly reduced.
Moreover, since the comparative example 1 did not have an adhesive under layer, the high-temperature adhesive strength was reduced (a comparative example corresponding to the invention of Japanese Patent Application No. 2006-207472 relating to the prior application of the present applicant). The reason why the adhesion amount of the heat-sensitive adhesive layer was increased (20 g / m ² ) was because there was no adhesive under layer.
Moreover, since Comparative Example 2 did not contain triphenylphosphine in the heat-sensitive adhesive layer, the low-temperature adhesive strength was reduced (Comparative Example corresponding to the invention of Patent Document 1).

Example 11
For the heat-sensitive adhesive label sheet of Example 9, the adhesive strength was measured at room temperature (23 ° C.) in the same manner as in the above <Adhesive strength measurement>. Furthermore, the adhesive force was measured in the same manner except that the sample was left at room temperature for 10 minutes after being thermally activated and affixed to the adherend. The results are shown in Table 4.

表４の結果から、実施例１１では、比較例３に比べて、熱源を取り除いた後も粘着性を長時間維持すること、即ち、ディレード性が優れていることが分かる。 Comparative Example 5
The adhesive strength of the heat-sensitive adhesive label sheet of Comparative Example 1 was measured in the same manner as in Example 11. The results are shown in Table 4.

From the results of Table 4, it can be seen that in Example 11, the adhesiveness is maintained for a long time after removing the heat source, that is, the delay property is excellent, as compared with Comparative Example 3.

Claims (7)

On one surface of the support, at least an adhesive under layer mainly composed of a thermoplastic resin having a Tg of −70 ° C. to −10 ° C., an intermediate layer mainly composed of a thermoplastic resin and plastic spherical hollow particles, and a thermosensitive adhesive It has a material layer in this order, together with the heat-sensitive adhesive layer, a thermoplastic resin, containing a tackifier and a heat melting substance and containing at least triphenyl phosphine as heat fusible material, the intermediate The thermoplastic resin of the layer is acrylic acid ester copolymer, methacrylic acid ester copolymer, acrylic acid ester-methacrylic acid ester copolymer, acrylic acid ester-styrene copolymer, acrylic acid ester-methacrylic acid ester-styrene. A heat-sensitive adhesive material, which is at least one selected from a copolymer and an ethylene-vinyl acetate copolymer . The heat-sensitive adhesive material according to claim 1, further comprising a benzotriazole compound represented by the following general formula (1) as the heat-meltable substance.

[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 either a hydrogen atom or a halogen atom. ]   The heat-sensitive adhesive material according to claim 1 or 2, wherein the content of triphenylphosphine in the hot-melt material is 60 to 80% by weight. The heat-sensitive adhesive material according to claim 1, wherein the dry adhesion amount of the heat-sensitive adhesive layer is 5 to 15 g / m ² . Plastic spherical hollow particles of the intermediate layer, the hollow of 70% or more, a maximum particle size of 10.0μm or less, the volume average particle diameter of claims 1-4, characterized in that the 2.0~5.0μm The heat-sensitive adhesive material according to any one of the above. The support has at least a heat-sensitive recording layer on a surface not having a heat-sensitive adhesive layer, and the heat-sensitive recording layer contains at least a leuco dye, a developer, and a binder resin. The heat-sensitive adhesive material according to any one of 1 to 5 . The heat-sensitive adhesive material according to any one of claims 1 to 6 , wherein the shape is any one of a label shape, a sheet shape, a label sheet shape, and a roll shape.