JP5532546B2 - Heat sensitive adhesive and heat sensitive adhesive material - Google Patents

Description

  The present invention is water that is non-adhesive at normal temperature but exhibits adhesiveness by heating, and persists even after the occurrence of adhesiveness, and particularly has sufficient adhesive strength to rough surface adherends such as corrugated cardboard. The present invention relates to a dispersion-type heat-sensitive adhesive and a heat-sensitive adhesive material.

  Conventionally, heat-sensitive adhesives are often used as water-dispersed pressure-sensitive adhesives as represented by known delayed tack-type pressure-sensitive adhesives in order to maintain the pressure-sensitive adhesiveness after the development of the pressure-sensitive adhesiveness. For example, as described in Non-Patent Document 1, a basic composition is a thermoplastic resin, a tackifier, and a solid plasticizer. The thermoplastic resin is a base of adhesive strength and adhesive strength. Since the solid plasticizer is solid at normal temperature, it does not give plasticity to the resin, but melts by heating and swells or softens the resin, so that it exhibits adhesiveness by heating to a non-adhesive adhesive at normal temperature. Works. At this time, if a tackifier is present, the tackiness appears more remarkably and the practical properties are improved. Such a heat-sensitive adhesive is coated on a plastic substrate such as high-quality paper, coated paper, art paper, vapor-deposited paper, or a PET film, and adheres to metal, glass, plastic, or the like. Used to paste.

Patent Document 1 and Patent Document 2 propose a delayed tack type adhesive using benzophenone as a solid plasticizer. However, this proposed pressure-sensitive adhesive has adhesive strength against mirror surfaces such as polyolefin and glass, but it has weak adhesive strength against rough surface adherends such as corrugated cardboard. As a result, it has become a major impediment to practical use in logistics such as courier services.
Patent Document 3 proposes a heat-sensitive adhesive material containing a hindered phenol compound, a benzotriazole compound, and an aromatic sulfonamide compound, and further containing hollow particles having a hollow ratio of 50% in the under layer. Yes. However, even when the proposed heat-sensitive adhesive material is used, the adhesiveness and blocking resistance to rough surface adherends such as corrugated cardboard are not fully satisfactory.

  Patent Document 4 proposes a delayed tack paste using benzotriazole as a solid plasticizer. It is relatively excellent in blocking resistance, and as an adherend, a long-term stable adhesive force can be maintained for materials such as paper, glass and metal, and polyolefin resins such as polypropylene and polyethylene. However, this proposed delayed tack paste also has a problem that the adhesive force to a rough surface adherend such as cardboard is insufficient.

  As a delayed tack paste having excellent adhesion properties to cardboard, a paste using a phosphorus compound as a solid plasticizer has been proposed (see Patent Document 5, Patent Document 6, and Patent Document 7). In addition, a heat-sensitive adhesive material having an adhesive under layer, a hollow intermediate layer, and a heat-sensitive adhesive layer on a support has been proposed (see Patent Document 8). However, in these proposals, if an attempt is made to increase the adhesive strength of cardboard in a low temperature environment, blocking occurs at 60 ° C. storage, and an attempt to improve the blocking quality at 60 ° C. storage results in an adhesion in a low temperature environment. There is a problem that power decreases.

  Blocking is a phenomenon in which the heat-sensitive adhesive develops adhesiveness during storage of the sample, and may be induced when exposed to a temperature atmosphere higher than room temperature for a long time. In either case of a roll state or a state in which the sheet is cut and stacked, once blocking is induced, the heat-sensitive adhesive layer and the outer surface (the surface opposite to the heat-sensitive adhesive layer across the support) are formed. Adhering will not only hinder paper feeding, but will also adversely affect printing on the outer surface.

Therefore, as a means for preventing blocking, a method of blending an anti-blocking agent or slippery wax in the heat-sensitive adhesive (see Patent Document 9), protecting the surface of the solid plasticizer with an inorganic compound or colloid particles, A method of preventing blocking by suppressing softening of a solid plasticizer (see Patent Document 10, Patent Document 11, and Patent Document 12) has been proposed. However, these proposals not only have an anti-blocking effect when blended with an anti-blocking agent and a wax, but conversely bring about a decrease in tackiness. In addition, if the surface of the solid plasticizer is protected with an inorganic compound and colloidal particles, it takes time to melt or diffuse the solid plasticizer, and the adhesiveness of the heat-sensitive adhesive is difficult to appear, causing problems such as a decrease in adhesive performance. This is insufficient for practical use.
Patent Document 13 proposes that a petroleum resin having a softening point of 110 ° C. or higher and lower than 150 ° C. is used as a tackifier. However, in this proposal, there is a problem that the blocking quality at 60 ° C. is insufficient and the adhesive force to a rough adherend such as cardboard is insufficient.

Moreover, the adhesive sheet which prescribed | regulated the content rate of the low molecular-weight component in a tackifier is proposed (refer patent document 14). However, this proposal is not a heat-sensitive adhesive containing a solid plasticizer, but prevents fogging of the windshield of automobiles. What is the technology to improve the adhesive strength and blocking resistance of heat-sensitive adhesives? The effect and purpose are different.
In addition, as a method for preparing a tackifier emulsion obtained by emulsification in the presence of a polymer emulsifier, for example, Patent Documents 15 to 17 describe the properties as a pressure-sensitive adhesive and the stability of the tackifier emulsion. The effect and purpose of the heat-sensitive pressure-sensitive adhesive containing the solid plasticizer of the present invention are different from those of the technology for improving the adhesive strength and the technology for improving the blocking property.

  Therefore, a heat-sensitive adhesive and a heat-sensitive adhesive material that can maintain adhesive strength for a long time even in a low-temperature environment such as corrugated cardboard and have good blocking resistance have not yet been obtained. The current situation is that prompt provision is desired.

JP 2003-206455 A JP 2002-38123 A JP 2002-105414 A Japanese Patent No. 3556414 JP 2006-257163 A JP 2006-257320 A JP 2007-77288 A JP 2006-83196 A Japanese Examined Patent Publication No. 62-21835 JP-A-6-57223 Japanese Patent Laid-Open No. 6-100907 Japanese Patent Application Laid-Open No. 6-100848 JP 2000-96021 A JP 2006-152128 A Japanese Patent No. 3350910 JP 2005-200440 A JP 2007-2106 A "Handbook of Adhesion", 12th edition, pages 131-135, published in 1970

  This invention is made | formed in view of this present condition, and makes it a subject to solve the said various problems in the past and to achieve the following objectives. That is, the present invention is a water-dispersed heat-sensitive adhesive that can maintain adhesive strength for a long time even in a low-temperature environment such as a corrugated cardboard, and has good blocking resistance. An object is to provide a heat-sensitive adhesive material.

Means for solving the problems are as follows. That is,
<1> Containing at least a thermoplastic resin, a solid plasticizer, and a tackifier,
The heat-sensitive adhesive is characterized in that the proportion of the component having a molecular weight of 300 or less in the tackifier is 4.2% by mass or less based on the total solid content of the tackifier.
<2> The heat-sensitive adhesive according to <1>, wherein the solid plasticizer is a compound represented by at least one of the following structural formulas (1) to (3).
However, in the structural formula (1), R ¹ and R ² may be the same as or different from each other, and represent any one of a hydrogen atom, an alkyl group, and an α, α-dimethylbenzyl group. . X represents either a hydrogen atom or a halogen atom.
<3> A heat-sensitive adhesive material comprising a support and a heat-sensitive adhesive layer comprising the heat-sensitive adhesive according to any one of <1> to <2> on the support. .
<4> The heat-sensitive adhesive material according to <3>, which has an under layer between the heat-sensitive adhesive layer and the support.
<5> The heat-sensitive adhesive material according to <4>, wherein the under layer is a hollow under layer containing hollow particles.
<6> The heat-sensitive adhesive material according to <4>, wherein the under layer includes an adhesive under layer and a hollow under layer containing hollow particles.
<7> The heat-sensitive adhesive material according to any one of <3> to <6>, wherein adhesiveness is exhibited by heating with a line-type thermal head.
<8> The heat-sensitive adhesive material according to any one of <3> to <7>, wherein the support has a recording layer on the side opposite to the surface having the heat-sensitive adhesive layer.

The heat-sensitive adhesive of the present invention contains at least a thermoplastic resin, a solid plasticizer, and a tackifier,
The proportion of the component having a molecular weight of 300 or less in the tackifier is 4.2% by mass or less based on the total solid content of the tackifier, so that even in a low temperature environment on a rough surface adherend such as corrugated cardboard. A water-dispersed heat-sensitive pressure-sensitive adhesive that can maintain the adhesive force for a long time and has good blocking resistance is obtained.

  According to the present invention, conventional problems can be solved, adhesive strength can be maintained for a long time even in a low temperature environment such as corrugated cardboard, and blocking resistance is also good. A water-dispersible heat-sensitive adhesive and a heat-sensitive adhesive material can be provided.

(Thermosensitive adhesive)
The heat-sensitive adhesive of the present invention contains a thermoplastic resin, a solid plasticizer, and a tackifier, and further contains other components as necessary.

-Tackifier-
The ratio (ratio) of components having a molecular weight of 300 or less in the tackifier is 4.2% by mass or less, preferably 1.0% by mass or less, based on the total solid content of the tackifier. When the said ratio exceeds 4.2 mass%, when it preserve | saves in a roll state in a high temperature environment (60 degreeC), blocking may arise.
Here, the adjustment of the proportion of the component having a molecular weight of 300 or less in the tackifier can be performed by a known removal treatment method such as atmospheric pressure or reduced pressure distillation or steam distillation.
The tackifier has a mass average molecular weight of preferably 500 to 10,000, and more preferably 1,000 to 3,000.
The molecular weight distribution and the mass average molecular weight of the tackifier can be measured by, for example, a GPC (Gel Permeation Chromatography) method.

  There is no restriction | limiting in particular as said tackifier, Various well-known things can be used, For example, rosins, rosin derivatives, petroleum resin, terpene resin etc. are mentioned. These may be used individually by 1 type and may use 2 or more types together.

Examples of the rosins include raw material rosins such as gum rosin, wood rosin and tall oil rosin, stabilized rosin obtained by disproportionating or hydrogenating the raw material rosin, and polymerized rosin.
Examples of the rosin derivative include rosin esters and rosin phenols.
Examples of the rosin esters include (1) a rosin ester obtained by esterification reaction of the rosin and a polyhydric alcohol, and (2) a raw material rosin partially fumarated or maleated and then esterified. Partially maleated or partially fumarized polyhydric alcohol ester, (3) Partial maleinization or partial fumaration obtained by partially fumarating or maleating the raw material rosin, then disproportionating and then esterifying And polyhydric alcohol esters of disproportionated rosin. The rosin phenols are those obtained by adding phenols to rosins and thermally polymerizing them, or subsequently esterifying them.
There is no restriction | limiting in particular as polyhydric alcohol used for the said esterification, According to the objective, it can select suitably, For example, diethylene glycol, glycerin, a trimethylol propane, a trimethylol ethane, 1,2, 6-hexane triol, 1,2,4-butanetriol, pentaerythritol, and the like.

Examples of the petroleum resins include C5 petroleum resins, C9 petroleum resins, C5 to C9 copolymer petroleum resins, coumarone resins, coumarone-indene resins, pure monomer resins, dicyclopentadiene petroleum resins, or these A hydride etc. are mentioned.
Examples of the terpene resin include aromatic-modified terpene resins obtained by copolymerizing terpenes such as α-pinene resin, β-pinene resin, α-pinene, and β-pinene and aromatic monomers such as styrene, or These hydrides are exemplified.
Among these, polymerized rosin or terpene phenol resin is particularly preferable from the viewpoint of adhesiveness to cardboard.

  The softening point of the tackifier is preferably 125 ° C to 200 ° C, and more preferably 150 ° C to 200 ° C from the viewpoint of blocking resistance.

The tackifier is preferably emulsified in the presence of a low molecular emulsifier and used as a tackifier emulsion.
The low molecular emulsifier is not particularly limited and may be any form of emulsifier, but an anionic emulsifier and a nonionic emulsifier can be suitably used.
Examples of the anionic emulsifier include alkyl sulfate anion emulsifiers such as sodium lauryl sulfate, ammonium lauryl sulfate, and potassium lauryl sulfate; polyoxyethylene alkyl ether sulfate anion emulsifiers such as sodium polyoxyethylene lauryl ether sulfate; Polyoxyethylene alkylphenyl ether sulfate-type anionic emulsifiers such as ammonium oxyethylene lauryl phenyl ether sulfate and sodium polyoxyethylene lauryl phenyl ether sulfate; Sulfonate-type anionic emulsifiers such as sodium dodecylbenzenesulfonate; Disodium lauryl sulfosuccinate And sulfosuccinic acid type anionic emulsifiers such as polyoxyethylene sulfosuccinate disodium lauryl.
Examples of the nonionic emulsifier include polyoxyethylene alkyl ether type nonionic emulsifiers such as polyoxyethylene lauryl ether; polyoxyethylene alkylphenyl ether type nonionic emulsifiers such as polyoxyethylene lauryl phenyl ether; polyoxyethylene fatty acid esters; And polyoxyethylene polyoxypropylene block polymer.

  The amount of the low-molecular emulsifier used is not particularly limited and may be appropriately selected depending on the purpose. It is preferably 1 part by mass to 10 parts by mass in terms of solid content with respect to 100 parts by mass of the tackifier, 2 mass parts-7 mass parts are more preferable. When the amount used exceeds 10 parts by mass, the adhesive strength of the heat-sensitive adhesive obtained is lowered, and when it is less than 1 part by mass, the storage stability of the emulsion-type tackifying resin may be deteriorated.

  There is no restriction | limiting in particular as an emulsification method, The conventionally well-known high pressure emulsification method, inversion emulsification method, etc. are employable. Specifically, (1) After the tackifier is dissolved in a solvent such as benzene or toluene, the low molecular emulsifier and soft water are added, emulsified using a high pressure emulsifier, and then the solvent is removed under reduced pressure. Method (2) A small amount of a solvent such as benzene or toluene is mixed with a tackifier, followed by kneading an emulsifier, and then gradually adding hot water to phase inversion emulsification to obtain an emulsion. (3) The temperature is raised above the softening point of the resin under pressure or normal pressure, and after kneading the emulsifier, hot water is gradually added to phase inversion emulsification. And a method of emulsifying them.

  There is no restriction | limiting in particular in the solid content concentration of the said emulsion type tackifier, According to the objective, it can select suitably, 20 mass%-70 mass% are preferable, and 40 mass%-60 mass% are more preferable. The average particle size of the emulsion-type tackifier is preferably 0.2 μm to 2 μm, and most of them are uniformly dispersed as particles of 0.5 μm or less. The emulsion-type tackifier exhibits a white to milky white appearance and has a pH of about 2 to 9.

  The content of the tackifier in the heat-sensitive adhesive is solid content, preferably 1% by mass to 30% by mass, and more preferably 1% by mass to 20% by mass. When the content is less than 1% by mass, the adhesive strength may be remarkably lowered. When the content is more than 30% by mass, a storage defect (decrease in blocking resistance) occurs at a normal storage environment temperature and a low temperature. Decrease in initial adhesive strength in the environment may occur.

  The emulsion-type tackifier is blended with a thermoplastic resin as a base resin and a solid plasticizer, and used as the heat-sensitive adhesive of the present invention.

-Thermoplastic resin-
There is no restriction | limiting in particular as said thermoplastic resin, Although it can select suitably according to the objective, A (meth) acrylic-type polymer emulsion is used suitably. The (meth) acrylic polymer emulsion is not particularly limited, and those generally used for various acrylic pressure-sensitive adhesives can be used. For example, (meth) acrylic acid ester is charged all at once, polymerization method, monomer sequential addition It can be easily produced by a known emulsion polymerization method such as a polymerization method, an emulsion monomer sequential addition polymerization method or a seed polymerization method.

Examples of the (meth) acrylic acid ester include methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, glycidyl (meth) acrylate, (meth ) 2-hydroxyethyl acrylate, and the like. These may be used individually by 1 type and may use 2 or more types together.
Further, in order to impart storage stability to the obtained emulsion, a small amount of (meth) acrylic acid may be used instead of the (meth) acrylic acid ester. Furthermore, a copolymerizable monomer such as vinyl acetate or styrene can be used in combination as long as it does not impair the adhesive properties of the (meth) acrylic acid ester polymer.

As for the glass transition temperature of the polymer which has the said (meth) acrylic acid ester as a main component, -70 degreeC--30 degreeC is preferable. When the glass transition temperature is higher than −30 ° C., the tackiness may be lowered, and when it is lower than −70 ° C., the blocking resistance may be lowered.
The emulsifier used in the acrylic polymer emulsion may be an anionic emulsifier, partially saponified polyvinyl alcohol, etc., and the amount used is preferably 0.1 to 5 parts by mass with respect to 100 parts by mass of the polymer. 0.5 parts by mass to 3 parts by mass is more preferable.
The content of the thermoplastic resin in the heat-sensitive adhesive is preferably 10% by mass to 60% by mass, and more preferably 15% by mass to 50% by mass. When the content of the thermoplastic resin is less than 10% by mass or more than 60% by mass, both of them are not preferable because the adhesive strength is lowered. On the other hand, when the content of the low glass transition temperature (Tg) resin exceeds 60% by mass, there may be a storage defect (blocking) such as an adhesive force developed at a normal storage environment temperature.

-Solid plasticizer-
The solid plasticizer is solid at room temperature and melts when heated. The melting point of the solid plasticizer is preferably 80 ° C. or higher, and the upper limit is about 200 ° C. When the melting point is less than 80 ° C., when it is used as a heat-sensitive adhesive, a storage defect (blocking) occurs, for example, an adhesive force develops at a normal storage environment temperature. In addition, there may be a problem in manufacturing such as that the adhesive force is developed when the heat-sensitive adhesive layer coating solution is applied to the substrate and dried. When the melting point exceeds 200 ° C., a large amount of energy is required to develop the adhesive force, resulting in practical problems. In addition, when a thermal recording paper is used as a base material and an adhesive force is expressed with a large amount of energy, there is a problem that a printed image cannot be read because the thermal recording layer is colored.

  Examples of the solid plasticizer include a benzotriazole compound represented by the following structural formula (1), a triphenylphosphine compound represented by the following structural formula (2), a compound represented by the following structural formula (3), Further, hydroxybenzoic acid ester compounds represented by the following structural formula (4), compounds represented by the following structural formulas (5) to (11), and the like can be given.

However, in the structural formula (1), R ¹ and R ² may be the same as or different from each other, and represent any one of a hydrogen atom, an alkyl group, and an α, α-dimethylbenzyl group. . X represents either a hydrogen atom or a halogen atom.

As the alkyl group in the structural formula (1), those having 1 to 8 carbon atoms are preferable, for example, methyl group, ethyl group, n-propyl group, n-butyl group, n-pentyl group, n-hexyl group. , N-heptyl group and the like, 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.

  Examples of the benzotriazole compound represented by the structural 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-amyl) Phenyl) 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) 3'-sec-butyl-5'-t-butylphenyl) benzotriazole, and the like.

[Structural formula (4)]
However, in said structural formula (4), R < ³ > is a C1-C18 alkyl group, a cyclohexyl group, an alkenyl group, an aralkyl group (the aromatic ring may have a substituent), and a phenyl group Represents one of the following.

  Examples of the hydroxybenzoic acid ester compound represented by the structural formula (4) include, for example, 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.

[Structural formula (5)]
However, in the structural formula (5), R ⁴ and R ⁵ may be the same as 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.

[Structural formula (6)]
However, in the structural formula (6), 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.

[Structural formula (7)]
However, in the structural formula (7), R ⁷ represents any one of a hydrogen atom, a halogen atom, an alkyl group, and an alkoxy group.

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

Examples of the compound represented by the structural formula (5) 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.
Examples of the compound represented by the structural formula (6) 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-naphtho Acid-p-chlorophenyl, 1,4-dihydroxy-2-naphthoic acid-o-chlorophenyl and the like can be mentioned. These may be used individually by 1 type and may use 2 or more types together.

  Examples of the compound represented by the structural formula (7) include benzoic acid-3-hydroxyphenyl, benzoic acid-4-hydroxyphenyl, benzoic acid-2-hydroxyphenyl, o-methylbenzoic acid-3-hydroxyphenyl, p-chlorobenzoic acid-3-hydroxyphenyl, and the like.

[Structural formula (8)]
However, in the structural formula (8), R ¹ and R ² may be the same as or different from each other, and represent a hydrogen atom or an alkyl group. m and n represent the integer of 1-5.

[Structural formula (9)]

[Structural formula (10)]
However, in the structural formula (10), R ¹ represents a hydrogen atom or an alkyl group. n represents an integer of 1 to 5.

The solid plasticizers represented by the structural formulas (1) to (10) can be used by pulverizing them to a volume average particle size of 10 μm or less, preferably 3 μm or less. Further, by making the volume average particle diameter finer, for example, 0.5 μm or less, the dynamic thermal sensitivity is increased and the thermoplastic resin and the tackifier are compatible with low energy to become a thermoactive adhesive.
The solid plasticizer can be used in combination with the compounds represented by the structural formulas (1) to (10) at an arbitrary ratio in addition to using one kind alone, but the mixing ratio in that case is arbitrary. It is possible to adjust.

In the present invention, as a solid plasticizer from the viewpoint of adhesiveness to corrugated cardboard in an environment of 0 ° C., at least one of the structural formula (1), the structural formula (2), and the structural formula (3). It is preferable to use the compound represented, The mixture of the said Structural formula (1) and the said Structural formula (2), and the compound of the said Structural formula (3) are especially preferable.
The content of the solid plasticizer in the heat-sensitive adhesive is preferably 25% by mass to 80% by mass, and more preferably 35% by mass to 70% by mass. When the content of the solid plasticizer is less than 25% by mass, when combined with a thermoplastic resin, blocking is likely to occur and the adhesive strength may be reduced. When the content exceeds 80% by mass, the adhesive strength is increased. Reduction may occur.
The content of triphenylphosphine represented by the structural formula (2) in the solid plasticizer is preferably 80% by mass to 95% by mass, and more preferably 80% by mass to 90% by mass. When the content of triphenylphosphine is less than 80% by mass, there is a problem that the adhesive force immediately after pasting at 23 ° C. to 40 ° C. is weak, and when it exceeds 95% by mass, the delay and blocking resistance are deteriorated. There are things to do.

  If necessary, other components such as a eutectic agent, a dispersant, an antifoaming agent, a thickener, and an antiblocking agent can be added to the heat-sensitive adhesive.

(Heat-sensitive adhesive material)
The heat-sensitive adhesive of the present invention can be used as a heat-sensitive adhesive material by applying a heat-sensitive adhesive on a support.

  The heat-sensitive adhesive material of the present invention comprises a support and a heat-sensitive adhesive layer on one surface of the support, and an under layer between the support and the heat-sensitive adhesive layer as necessary. (Intermediate layer) can be provided, and further has other layers as required. Various recording layers and protective layers can be provided on the other surface of the support that does not have the heat-sensitive adhesive layer.

  The support is not particularly limited in its shape, structure, size and the like, and can be appropriately selected according to the purpose. Examples of the shape include a flat plate shape, May be a single layer structure or a laminated structure, and the size may be appropriately selected according to the size of the heat-sensitive adhesive material.

There is no restriction | limiting in particular as a material of the said support body, Although it can select suitably according to the objective, It divides roughly into an inorganic material and an organic material. Examples of the inorganic material include glass, quartz, silicon, silicon oxide, aluminum oxide, SiO ₂ and metal. Examples of the organic material 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, poly Examples thereof include polyolefins such as methyl 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. In addition, it is preferable to add a white pigment such as titanium oxide to the support.
There is no restriction | limiting in particular as thickness of the said support body, Although it can select suitably according to the objective, 50 micrometers-2,000 micrometers are preferable and 100 micrometers-1,000 micrometers are more preferable.
By applying the heat-sensitive adhesive of the present invention to one surface of a substrate, a heat-sensitive adhesive material having strong adhesive strength against vinyl chloride wrap and polyolefin wrap, particularly cardboard, and good blocking resistance can be obtained.

The heat-sensitive adhesive material is produced, for example, by coating with a conventionally known bar coater, roll coater, applicator, hot melt coater or the like, followed by drying with hot air, infrared rays, microwaves, high frequency or the like.
The coating amount of the heat-sensitive adhesive layer, dry coating amount in the normal ^{2g / m 2 ~35g / m 2} , preferably applied in the range of ^{5g / m 2 ~25g / m 2} . When the coating amount of the heat-sensitive adhesive layer is less than 2 g / m ² , sufficient adhesion cannot be obtained when performing adhesion by heating. In addition, when it exceeds 35 g / m < ² >, an adhesive function will be saturated and it is not preferable economically.

<Under layer>
In this invention, the adhesive force with a to-be-adhered body can be improved by providing an under layer between the said thermosensitive adhesive layer and a support body.
The under layer includes a hollow under layer containing hollow particles and an adhesive under layer, (1) an embodiment having only a hollow under layer, and (2) an embodiment having an adhesive under layer and a hollow under layer. Can be mentioned. In the case of (2), it is preferable to provide an adhesive under layer and a hollow under layer in this order on the support.

-Hollow under layer-
The hollow under layer contains at least a thermoplastic resin and hollow particles, and further contains other components as necessary.
By providing the hollow under layer, the thermal efficiency can be improved and the adhesive strength can be improved.

  The thermoplastic resin may be a thermoplastic resin having a glass transition temperature (Tg) of −70 ° C. to −30 ° C. Examples of these resins include natural rubber latex obtained by graft copolymerization with a vinyl monomer, styrene- Butadiene copolymer, acrylic acid ester copolymer, methacrylic acid ester copolymer, acrylic acid ester-methacrylic acid ester copolymer, acrylic acid ester-acrylonitrile copolymer, acrylic acid ester-acrylonitrile-vinyl acetate-copolymer Examples thereof include an acrylic ester-styrene copolymer, an acrylic ester-methacrylic ester-styrene copolymer, and an ethylene-vinyl acetate copolymer. These may be used individually by 1 type and may use 2 or more types together. Among these, acrylic ester copolymer, acrylic ester-acrylonitrile copolymer, acrylic ester-acrylonitrile-vinyl acetate-copolymer, acrylic ester-styrene copolymer, acrylic ester-methacrylic ester- Styrene copolymers are particularly preferred.

As the hollow particles, spherical plastic hollow particles having a volume average particle diameter of 2.0 μm to 5.0 μm and a hollow ratio of 70% or more are preferable, and the maximum particle diameter of the hollow particles is 10.0 μm or less. In addition, spherical hollow particles having a volume average particle diameter of 2.0 μm to 5.0 μm and a hollow ratio of 70% or more are more preferable. The hollowness is more preferably 85% to 95%.
If the hollow ratio is less than 70%, the heat insulation effect is insufficient, so that the heat energy from the thermal head is released to the outside through the support, and the effect of improving the adhesive strength may be inferior. When the volume average particle diameter exceeds 5.0 μm, when a heat-sensitive adhesive layer is provided on the under layer using such hollow particles, a portion where a heat-sensitive adhesive layer is not formed is formed in a large particle portion. When the thermal activation is performed, the adhesive strength may be easily reduced. When the thermal conductivity is less than 2.0 μm, it is difficult to secure a hollow ratio of 70% or more, and the adhesive strength improving effect may be inferior. .

  Here, the spherical plastic hollow particles mean hollow particles that are made of a thermoplastic resin as a shell and contain air or other gas inside and are already in a foamed state. The hollow ratio means the ratio of the volume based on the outer diameter and the volume based on the inner diameter of the hollow fine particles.

  The material of the spherical hollow particles is not particularly limited and may be appropriately selected depending on the intended purpose.For example, vinylidene chloride-acrylonitrile copolymer, acrylonitrile-vinylidene chloride-methyl methacrylate copolymer, acrylonitrile- Examples thereof include methacrylonitrile-isobonyl methacrylate copolymer.

  The mixing ratio of the thermoplastic resin having the glass transition temperature (Tg) in the hollow under layer of −70 ° C. to −30 ° C. and the hollow particles is 0.1% by weight of the hollow particles relative to 1 part by mass of the thermoplastic resin. Mass parts to 2 parts by mass are preferable, and 0.3 parts to 1 part by mass are more preferable. When the hollow particle is less than 0.1 part by mass, the effect of improving the adhesive strength may be inferior, and when it exceeds 2 parts by mass, the binding force of the hollow under layer may be inferior and the adhesive force may be weakened.

The hollow under layer is not particularly limited and can be formed according to a known method. For example, the hollow under layer can be suitably formed by a coating method using an under layer coating solution containing the above components.
As the coating method, for example, blade coating method, gravure coating method, gravure offset coating method, bar coating method, roll coating method, knife coating method, air knife coating method, comma coating method, U comma coating method, AKKU coating method, Examples thereof include a smoothing 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.

The coating amount of the hollow under layer coating solution is preferably ^1g / ^{m 2 ~35g} / m 2 on a dry coating ^{amount, 1g / m 2 ~5g / m} 2 is more preferable. When the coating amount of the under layer coating liquid is less than 1 g / m ² , sufficient adhesion cannot be obtained when performing adhesion by heating, and the heat insulation effect may be inferior, exceeding 35 g / m ² . Then, the adhesive force and the heat insulation effect may be saturated.

-Adhesive under layer-
In the present invention, the adhesive strength can be further improved by providing an adhesive under layer made of an adhesive resin between the hollow under layer containing the hollow particles and the support.
In this case, the coating amount of the hollow under layer in a dry coating amount ^is preferably from ^{1g / m 2 ~5g / m 2} , 1g / m 2 ~2g / m 2 is more preferable. When the coating amount of the hollow under layer is less than 1 g / m ² , the heat insulation effect during thermal activation is small, and when it exceeds 5 g / m ² , the effect of improving the adhesive force from the adhesive under layer is undesirably reduced. .
The coating amount of the adhesive under layer in a dry coating amount ^is preferably ^{2g / m 2 ~35g / m 2} , 4g / m 2 ~35g / m 2 is more preferable.

  As the thermoplastic resin in the adhesive under layer, a thermoplastic resin having a glass transition temperature (Tg) of −70 ° C. to −5 ° C. is suitable. For example, a vinyl monomer is graft-copolymerized as the thermoplastic resin. Natural rubber latex, 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 copolymer , Ethylene-vinyl acetate copolymer, and the like. In the case of a resin having a high glass transition temperature, the characteristics of the adhesive under layer and the intermediate layer are not obtained at all, the adhesive strength to a rough surface adherend such as cardboard is weak, and only the heat-sensitive adhesive layer provided in the upper layer It will be adhesive. On the other hand, most of the resins have a glass transition temperature (Tg) of −70 ° C. or higher, and there is no particular problem even in the case of a low Tg resin that is less than the Tg range of the thermoplastic resin. .

  The method for forming the adhesive under layer is not particularly limited and can be formed according to a known method. For example, the adhesive under layer obtained by stirring and dispersing the above-described components and, if necessary, other components in water. It can be suitably formed by a coating method using a layer coating solution. As the coating method, for example, blade coating method, gravure coating method, gravure offset coating method, bar coating method, roll coating method, knife coating method, air knife coating method, comma coating method, U comma coating method, AKKU coating method, Examples thereof include a smoothing 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.

<Thermosensitive adhesive layer>
The heat-sensitive adhesive layer comprises the heat-sensitive adhesive of the present invention.
The heat-sensitive adhesive of the present invention contains a thermoplastic resin and a heat-meltable substance, and contains a non-heat-meltable substance, a tackifier, and, if necessary, other components.
Details of these components are as described in the description of the heat-sensitive adhesive.

There is no restriction | limiting in particular as a formation method of the said thermosensitive adhesive layer, It can form according to a well-known method, for example, forms by the apply | coating method using the thermosensitive adhesive liquid formed by mix | blending each said component. Can do.
As the coating method, for example, blade coating method, gravure coating method, gravure offset coating method, bar coating method, roll coating method, knife coating method, air knife coating method, comma coating method, U comma coating method, AKKU coating method, Examples thereof include a smoothing 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 a drying condition at the time of the said application | coating or printing, it dries in the temperature range in which the hot-meltable substance used does not melt | dissolve. As the drying means, for example, in addition to hot air drying, a drying method using a heat source using infrared rays, microwaves, and high frequencies can be used.

The coating amount of the heat-sensitive adhesive liquid in a dry coating amount ^is preferably from ^{5g / m 2 ~30g / m 2} , 10g / m 2 ~20g / m 2 is more preferable. When the dry coating amount is less than 5 g / m ² , sufficient adhesive strength may not be obtained when pasting at a low temperature, and when it exceeds 30 g / m ² , the heat insulating effect of the under layer may be reduced. The economy is inferior.

  The heat-sensitive adhesive material of the present invention has a strong adhesive force in a low-temperature environment of 0 ° C. to 10 ° C., particularly against a rough adherend such as corrugated cardboard, and has good anti-blocking property, by having the above-described configuration. Furthermore, it is possible to develop adhesiveness (thermal activation) with low energy.

  Next, in the heat-sensitive adhesive material of the present invention, on the surface of the support that does not have the heat-sensitive adhesive layer, at least a recording layer is provided, and a protective layer and, if necessary, other layers are provided. Do it.

<Recording layer>
The heat-sensitive adhesive material of the present invention can record images and the like by providing a recording layer on the opposite surface of the heat-sensitive adhesive layer.
There is no restriction | limiting in particular as said recording layer, According to the objective, it can select suitably, For example, a heat sensitive recording layer, the ink receiving layer for thermal transfer recording, the ink receiving layer for inkjet, etc. are mentioned suitably.

[Thermosensitive adhesive material for thermal recording]
The heat-sensitive recording layer in the heat-sensitive adhesive material for heat-sensitive recording contains a leuco dye, a developer, and a binder resin, and further contains other components as necessary.

The leuco dye is not particularly limited and may be appropriately selected from known ones according to the purpose. Examples thereof include triphenylmethane dyes, fluoran dyes, phenothiazine dyes, auramine dyes, and spiropyran dyes. Indoline phthalide dyes are preferable.
Examples of the leuco dye include 3,3-bis (p-dimethylaminophenyl) phthalide, 3,3-bis (p-dimethylaminophenyl) -6-dimethylaminophthalide (also known as 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'-trifluoromethyl) Phenyl) amino} -6-diethylaminofluorane, 2- {3,6-bis (diethylamino) -9- (o-chloroanilino) xanthylbenzoate lactam}, 3-diethylamino-6-methyl-7- (m-trichloro) Methylanilino) fluorane, 3-diethylamino-7- (o-chloroanilino) fluorane, 3-dibutylamino-7- (o-chloroanilino) fluorane, 3-N-methyl-N-amylamino-6-methyl-7-ani Linofluorane, 3-N-methyl-N-cyclohexylamino-6-methyl-7-anilinofluorane, 3-diethylamino 6-methyl-7-anilinofluorane, 3- (N, N-diethylamino) -5-methyl-7- (N, N-dibenzylamino) 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'-diethylamino) Phenyl) -3- (2′-methoxy-5′-methylphenyl) phthalide, 3-diethylamino-6-methyl-7- (2 ′, 4′-dimethylanilino) fluoro 3- (2′-methoxy-4′-dimethylaminophenyl) -3- (2′-hydroxy-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-diethylamino-7-piperidinofluorane, 2-chloro-3- (N-methyltoluidino) -7- (pn-butylanilino) fluorane 3- (N-benzyl-N-cyclohexylamino) -5,6-benzo-7-α-naphthylamino-4 ′, 0-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- L} -6-dimethylaminophthalide, 3- (p-dimethylaminophenyl) -3- (1-p-dimethylaminophenyl-1-phenylethylene-2-yl) phthalide, 3- (p-dimethylaminophenyl) -3- (1-p-dimethylaminophenyl-1-p-chlorophenylethylene-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- -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-propylamino) -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-ethoxy Propyl) amino-6-methyl-7-anilinofluorane, 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-anilino Fluoran, etc. 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. Examples of the developer include 4,4′-isopropylidenebisphenol, 3,4′-isopropylidenebisphenol, 4,4′-isopropylidenebis (o-methylphenol), 4,4′-secondary butylidene. Bisphenol, 4,4′-isopropylidenebis (o-tertiarybutylphenol), 4,4′-cyclohexylidenediphenol, 4,4′-isopropylidenebis (2-chlorophenol), 2,2′-methylenebis ( 4-methyl-6-tertiarybutylphenol), 2,2′-methylenebis (4-ethyl-6-tertiarybutylphenol), 4,4′-butylidenebis (6-tertiarybutyl-2-methyl) phenol, 1, 1,3-tris (2-methyl-4-hydroxy-5-tertiary buty Phenyl) butane, 1,1,3-tris (2-methyl-4-hydroxy-5-cyclohexylphenyl) butane, 4,4′-thiobis (6-tertiarybutyl-2-methyl) phenol, 4,4 ′ -Diphenol sulfone, 4,2'-diphenol sulfone, 4-isopropoxy-4'-hydroxydiphenyl sulfone, 4-benzyloxy-4'-hydroxydiphenyl sulfone, 4,4'-diphenol sulfoxide, p-hydroxybenzoic acid Isopropyl acid, benzyl p-hydroxybenzoate, benzyl protocatechuate, stearyl gallate, lauryl gallate, octyl gallate, 1,7-bis (4-hydroxyphenylthio) -3,5-dioxaheptane, 1,5 -Bis (4-hydroxyphenylthio) -3-oxaheptane, , 3-bis (4-hydroxyphenylthio) -propane, 2,2′-methylenebis (4-ethyl-6-tertiarybutylphenol), 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, thiocyanate Zinc acid antipyrine complex, 2-acetyloxy-3-naphthoic acid zinc salt, 2-hydroxy-1-naphthoic acid, 1-hydroxy-2-naphthoic acid, hydroxynaphthoic acid zinc, aluminum, calcium and other metal salts 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, Antipyrine complex of 4′-diphenolsulfone, 3,3′-diallyl-4,4′-diphenolsulfone, α, α-bis (4-hydroxyphenyl) -α-methyltoluenethiocyanate zinc, tetrabromobisphenol A , Tetrabromobisphenol S, 4,4′-thiobis (2-methylphenol), 3,4-hydroxy-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.

  The addition amount of the developer in the heat-sensitive recording layer is not particularly limited and may be appropriately selected depending on the purpose. It is preferably 1 to 20 parts by weight with respect to 1 part by weight of the color former. More preferred is 10 parts by mass.

  There is no restriction | limiting in particular as said binder resin, According to the objective, it can select suitably according to the objective, 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 Water-soluble polymers such as acid copolymer alkali salts, polyacrylamide, sodium alginate, gelatin, casein; polyvinyl acetate, polyurethane, polyacrylic acid, polyacrylic acid ester, Emulsions such as methacrylic acid ester, polybutyl methacrylate, vinyl chloride-vinyl acetate copolymer, ethylene-vinyl acetate copolymer; latexes such as styrene-butadiene copolymer, styrene-butadiene-acrylic copolymer, etc. Is mentioned. 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. 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 Esters, 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-dibenzyloxynaphth Talene, 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, Benzyl disulfide, 1,1-diphenylethanol, 1,1-diphenylpropanol, p- (benzyloxy) benzyl alcohol, 1,3-diphenoxy-2-propanol, N-octadecylcarbamoyl-p-methoxycarbonylbenzene, N-octadecyl And carbamoylbenzene, succinic 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 thermosensitive recording layer, various auxiliary additive components such as a surfactant and a lubricant can be used in combination 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 can be formed by a generally known method. For example, a leuco dye and a developer are separately added together with a binder 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 μm to 3 μm, mix with a filler, heat fusible substance (sensitizer) dispersion, etc. as needed A thermal recording layer can be formed by preparing a thermal recording layer coating solution and applying the coating solution on a support.
The thickness of the heat-sensitive recording layer varies depending on the composition of the heat-sensitive recording layer, the use of the heat-sensitive adhesive material, and the like, and cannot be specified unconditionally, but is preferably 1 μm to 50 μm, more preferably 3 μm to 20 μm.

[Heat-sensitive adhesive material for thermal transfer recording or inkjet recording]
The ink-receiving layer for thermal transfer recording in the heat-sensitive adhesive material for thermal transfer recording or the ink-receiving layer in the heat-sensitive adhesive material for ink-jet recording contains a filler, a binder resin, and a water-resistant agent, and further if necessary. It contains other components.

  The filler is not particularly limited and can be appropriately selected depending on the purpose. For example, calcium carbonate, silica, titanium oxide, aluminum hydroxide, clay, calcined clay, magnesium silicate, magnesium carbonate, white carbon, Examples thereof include zinc oxide, barium sulfate, surface-treated calcium carbonate and silica, urea-formalin resin, styrene-methacrylic acid copolymer, and fine powders such as polystyrene.

There is no restriction | limiting in particular as said 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 Cellulose derivatives such as ethyl cellulose; polyacrylic acid soda, polyvinylpyrrolidone, acrylamide-acrylic acid ester copolymer, acrylamide-acrylic acid ester-methacrylic acid terpolymer, styrene-maleic anhydride copolymer alkali salt, isobutylene -Water-soluble polymer compounds such as anhydrous maleic copolymer alkali salt, polyacrylamide, sodium alginate, gelatin, casein and the like. These may be used individually by 1 type and may use 2 or more types together.
The ratio of the filler to the water-soluble resin in the ink receiving layer is related to blocking resistance, and the content ratio (solid content) is 0.1 part by mass of the water-soluble resin to 1 part by mass of the filler. 0.2 parts by mass is preferable.

The water-proofing agent is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include formaldehyde, glyoxal, chrome alum, melamine, melamine-formaldehyde resin, polyamide resin, and polyamide-epichlorohydrin resin. .
The ratio of the water-proofing agent and the water-soluble resin is also related to blocking resistance, and the content ratio (solid content) is 0.3 parts by weight to 0.3 parts by weight of the water-proofing agent with respect to 1 part by weight of the water-soluble resin. It is preferable to add 5 parts by mass. As described above, the ink receiving layer is formed by containing a filler and a water-soluble resin, and a specific ratio of the water-soluble resin and the water-resistant agent. Further, the surface of the ink receiving layer is smoothed by a calendar or the like. By performing the treatment so as to be at least 2 seconds, it is possible to further improve the printing quality in addition to the effect of the filler.

<Protective layer>
The protective layer can be provided on the recording layer for the purpose of imparting functions such as barrier properties, head matching properties, and blocking resistance to the recording layer.
The protective layer contains polyvinyl alcohol and a hydrazide compound, and further contains other components as necessary.
Among these, the protective layer containing polyvinyl alcohol having a reactive carbonyl group and a hydrazide compound as a crosslinking agent is extremely heat resistant and water resistant, and is hardly affected by the addition of pressure, temperature and humidity. The blocking property can be greatly improved.

  The polyvinyl alcohol having a reactive carbonyl group 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, and specifically, diacetone acrylamide and meta diacetone acrylamide are preferable. . Examples of the fatty acid vinyl ester include vinyl formate, vinyl acetate, and vinyl propionate. Among these, vinyl acetate is particularly preferable.

The polyvinyl alcohol (PVA) having a reactive carbonyl group may be obtained by copolymerizing another copolymerizable vinyl monomer. 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 the PVA having a reactive carbonyl group is preferably 0.5 mol% to 20 mol% of the whole polymer, and more preferably 2 mol% to 10 mol% in consideration of water resistance. If the content is less than 2 mol%, the water resistance may be insufficient in practice. If the content exceeds 10 mol%, the improvement in water resistance is not seen any more and the cost is increased. Moreover, 300-3,000 are preferable and, as for the polymerization degree of PVA which has the said reactive carbonyl group, 500-2,200 are more preferable. The saponification degree of the PVA having a reactive carbonyl group 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. These may be used individually by 1 type and may use 2 or more types together. Among these, adipic acid dihydrazide is particularly preferable in terms of water resistance and safety.
The content of the hydrazide compound is preferably 5 parts by mass to 40 parts by mass and more preferably 15 parts by mass to 25 parts by mass with respect to 100 parts by mass of the polyvinyl alcohol having the reactive carbonyl group.

  The protective layer preferably contains a filler. The filler is not particularly limited and may be appropriately selected depending on the intended purpose. For example, calcium carbonate, zinc oxide, aluminum oxide, titanium dioxide, silica, aluminum hydroxide, barium sulfate, talc, kaolin, alumina, clay Inorganic pigments such as, or known organic pigments. Among these, silica, kaolin and alumina which are acidic pigments (showing acidity in an aqueous solution) are preferable in consideration of water resistance (water peeling resistance), and silica is particularly preferable from the viewpoint of color density.

The method for forming the protective layer is not particularly limited, and can be formed by a generally known method. For example, a protective layer coating solution is prepared by a conventional method and applied onto the recording layer. A protective layer can be formed.
There is no restriction | limiting in particular in the thickness of the said protective layer, Although it can select suitably according to the objective, 1.0 micrometer-7.0 micrometers are preferable.

  An intermediate layer may be provided between the support and the thermosensitive recording layer as necessary. Examples of the component constituting the intermediate layer include a pigment containing the hollow particles, a binder, a thermofusible substance, and a surfactant.

The heat-sensitive adhesive material of the present invention can be suitably used by being cut before or after thermal activation (heating) of the heat-sensitive adhesive layer. In this case, the heat-sensitive adhesive material is preliminarily used in the heat-sensitive adhesive material. A cut may be formed, which is advantageous in that the heat-sensitive adhesive material can be suitably used for various uses such as labels and tags.
There is no restriction | limiting in particular as a 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 suitably. Among these, from the viewpoint of convenience, storage location, and handleability, it is preferable that the cylindrical core material is wound and stored in a roll shape.

  The adherend to which the heat-sensitive adhesive material of the present invention is affixed is not particularly limited, and its size, shape, structure, material, and the like can be appropriately selected according to the purpose. For example, polyolefin (polyethylene, polypropylene, etc.), acrylic, polyethylene terephthalate (PET), polystyrene, nylon and other resin plates; SUS, aluminum and other metal plates; envelopes, cardboard and other paper products; polyolefin wraps; Preferable examples include wraps made of polyethylene; non-woven fabric made of polyethylene (envelopes and the like).

  The method for thermally activating the heat-sensitive adhesive layer in 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, an activity using a hot roll, etc. And an activation method using a thermal head. Among these, an activation method using a thermal head is particularly preferable. In this case, it is advantageous in that recording on the heat-sensitive recording layer and thermal activation of the heat-sensitive adhesive layer can be performed by heating both surfaces of the heat-sensitive adhesive material using an existing heat-sensitive recording printer device. It is.

  The heat-sensitive adhesive material of the present invention can exhibit excellent adhesive strength in a low temperature environment (0 ° C.) or a room temperature environment by using the heat-sensitive adhesive of the present invention, and is suitable for rough surface adherends such as cardboard. A heat-sensitive adhesive material having strong adhesive force, good blocking resistance and excellent storage stability can be obtained. Further, by applying a recording layer on one side of the support and applying the heat-sensitive adhesive of the present invention on the other side, a low temperature (0 ° C.) environment for a rough surface adherend such as corrugated cardboard is used. C.) It is possible to obtain a heat-sensitive adhesive material for recording which has a strong adhesive force in an environment, can exhibit adhesiveness with a thermal head, and has good blocking resistance.

EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention further more concretely, this invention is not limited at all by these Examples.
In addition, the mass average molecular weight in the tackifier used by the Example and the comparative example and the ratio of the molecular weight 300 or less component were calculated | required as follows.

<Measurement of mass average molecular weight and molecular weight distribution>
Each tackifier was dissolved in tetrahydrofuran (THF) to prepare a 1 g / L THF solution of the tackifier and filtered through a membrane filter having a pore size of 0.5 μm. "HLC-8120GPC; column: TSKgel SuperHZ2000 / HZ2000 / HZ1000 / HZ1000 / HZ1000 (60 mm ID x 150 mm, 40 ° C); flow rate: 0.6 mL / min; detector: RI"], converted to polystyrene Was used to calculate the molecular weight distribution and the mass average molecular weight, and the proportion of components having a molecular weight of 300 or less was determined.

(Production Example 1)
-Preparation of emulsion type tackifier [A-1]-
100 parts by mass of polymerized rosin ester (made by Arakawa Chemical Co., Ltd., tackifier, trade name: Pencel D-125, softening point 125 ° C., mass average molecular weight 1619, ratio of components having a molecular weight of 300 or less 6.4% by mass) After dissolving in 60 parts by mass of toluene at 100 ° C. for about 1 hour, it was cooled to 80 ° C. Next, 3 parts by mass of a low molecular emulsifier (sodium dodecylbenzenesulfonate, trade name: Neogen R, manufactured by Kao Corporation) and 160 parts by mass of water are added and stirred vigorously at 75 ° C. for 1 hour. Pre-emulsification was performed. Furthermore, the obtained preliminary emulsion was high-pressure emulsified with a high-pressure emulsifier (mantongaurin) at a pressure of 300 kg / cm ² to obtain an emulsion. Next, 200 parts by mass of the emulsion was charged into a vacuum distillation apparatus, and vacuum distillation was performed for 8 hours under the conditions of 50 ° C. and 100 mmHg to prepare an emulsion-type tackifier [A-1] having a solid content of 50% by mass.

(Production Example 2)
-Preparation of emulsion type tackifier [A-2]-
Low boiling components of polymerized rosin ester (made by Arakawa Chemical Co., Ltd., tackifier, trade name: Pencel D-125, softening point 125 ° C., mass average molecular weight 1619) are removed by steam distillation, and components having a molecular weight of 300 or less are removed. An emulsion-type tackifier [A-2] was produced in the same manner as in Production Example 1 except that the purification treatment was performed so that the ratio was 0.8% by mass.

(Production Example 3)
-Preparation of emulsion type tackifier [A-3]-
60 parts by mass of polymerized rosin ester (manufactured by Arakawa Chemical Co., Ltd., tackifier, trade name: Pencel D-125, mass average molecular weight 1619, ratio of components having a molecular weight of 300 or less) is purified in Production Example 2. Production Example 1 except that 40 parts by mass of the treated polymerized rosin ester (a ratio of molecular weight of 300 or less: 0.8% by mass) was mixed so that the ratio of components having a molecular weight of 300 or less was 4.2% by mass. In the same manner, an emulsion type tackifier [A-3] was produced.

(Production Example 4)
-Preparation of emulsion type tackifier [A-4]-
65 parts by mass of polymerized rosin ester (made by Arakawa Chemical Co., Ltd., tackifier, trade name: Pencel D-125, mass average molecular weight 1619, ratio of component having a molecular weight of 300 or less) is purified in Production Example 2. Production Example 1 except that 35 parts by mass of the treated polymerized rosin ester (a ratio of molecular weight of 300 or less: 0.8% by mass) was mixed so that the ratio of components having a molecular weight of 300 or less was 4.4% by mass. In the same manner, an emulsion type tackifier [A-4] was produced.

(Production Example 5)
-Preparation of solid plasticizer dispersion [C-1]-
A mixture having the following composition was dispersed using a sand mill so that the volume average particle diameter was 1.0 μm to prepare a solid plasticizer dispersion [C-1].
-Triphenylphosphine (trade name: TPP, manufactured by Hokuko Chemical Co., Ltd.) ... 30 parts by mass- Vinyl alcohol and sodium allyl sulfonate copolymer (trade name: L-3266, manufactured by Nippon Synthetic Chemical Co., Ltd.) Average molecular weight 15,000, saponification degree 88%) 10% by weight aqueous solution 15 parts by weight Alkyl-allyl sulfonate (surfactant) 0.15 parts by weight Water 54.85 parts by weight Part

(Production Example 6)
-Preparation of solid plasticizer dispersion [C-2]-
A mixture having the following composition was dispersed using a sand mill so that the volume average particle diameter was 1.0 μm to prepare a solid plasticizer dispersion [C-2].
2- (2′-hydroxy-3′-t-butyl-5′-methylphenyl) -5-chlorobenzotriazole (trade name: Evesorb 73, manufactured by Sort) ... 30 parts by mass Vinyl alcohol and allyl sulfone Sodium acid copolymer 10% by mass aqueous solution (trade name: L-3266, manufactured by Nippon Synthetic Chemical Co., Ltd., number average molecular weight 15,000, saponification degree 88%) ... 15 parts by mass Alkyl-allyl sulfonate ( Product name: Newcol-290M, manufactured by Nippon Emulsifier Co., Ltd.) ... 0.15 parts by mass Water: 54.85 parts by mass

(Production Example 7)
-Preparation of solid plasticizer dispersion [C-3]-
A mixture having the following composition was dispersed using a sand mill so that the volume average particle diameter was 1.0 μm to prepare a solid plasticizer dispersion [C-3].
Diethyl [[3,5-bis (1,1-dimethylethyl) -4-hydroxyphenyl] methyl] phosphonate (trade name: PRONOX 1222, manufactured by Sort Co., Ltd.) 30 parts by mass Vinyl alcohol and allyl sulfonic acid Sodium copolymer 10 mass% aqueous solution (trade name: L-3266, manufactured by Nippon Synthetic Chemical Co., Ltd., number average molecular weight 15,000, saponification degree 88%) ... 15 parts by mass ・ Alkyl-allyl sulfonate (product) Name: Newcol-290M, manufactured by Nippon Emulsifier Co., Ltd.) ... 0.15 parts by mass Water: 54.85 parts by mass

(Production Example 8)
-Preparation of hollow underlayer coating solution [D-1 solution]-
・ Plastic spherical hollow particles (acrylonitrile / vinylidene chloride / methyl methacrylate copolymer, solid content 41% by mass, average particle size 3.6 μm, hollow rate 90%) ... 14.6 parts by mass Thermoplastic resin emulsion ( 2-ethylhexyl acrylate resin main component, Showa Polymer Co., Ltd., AP5570, solid content 55% by mass, glass transition temperature (Tg) = − 65 ° C.) 24.0 parts by mass Surfactant (Dapro W-77, manufactured by Elementis Japan Co., Ltd.) ... 0.1 parts by mass Water ... 60.4 parts by mass A mixture of the above composition was stirred and dispersed to form a hollow underlayer coating solution [D-1 solution]. Was prepared.

(Production Example 9)
-Preparation of adhesive underlayer coating solution [D-2 solution]-
The mixture of the following composition was stirred and the adhesion underlayer coating liquid [D-2 liquid] was prepared.
Thermoplastic resin emulsion (acrylic acid-2-ethylhexyl resin main component, Showa Polymer Co., Ltd., AP5570, solid content 55% by mass, glass transition temperature (Tg) = − 65 ° C.) 100.0 parts by mass・ Surfactant (Dapro W-77, manufactured by Elementis Japan) ... 0.1 parts by mass

Example 1
-Preparation of water-dispersed thermosensitive adhesive liquid [E-1 liquid]-
Emulsion type tackifier [A-2 liquid] 8.1 parts by mass Thermoplastic resin emulsion (acrylic acid-2-ethylhexyl resin main component, manufactured by Showa Polymer Co., Ltd., AP5570, solid content 55% by mass , Glass transition temperature (Tg) = − 65 ° C.) 8.1 parts by mass Solid plasticizer dispersion [C-1 liquid] 49.1 parts by mass Solid plasticizer dispersion [C-2 Liquid] ... 32.7 parts by mass Water ... 2.0 parts by mass A mixture of the above composition was stirred to prepare a water-dispersed thermosensitive adhesive liquid [E-1 liquid].

(Example 2)
-Preparation of water-dispersed thermosensitive adhesive liquid [E-2 liquid]-
In Example 1, except that the emulsion type tackifier [A-2 solution] was changed to [A-3 solution], a water-dispersed thermosensitive adhesive solution [E-2 solution] was used in the same manner as in Example 1. Was prepared.

(Example 3)
-Preparation of water-dispersed thermosensitive adhesive liquid [E-3 liquid]-
A water-dispersed thermosensitive adhesive liquid [E-3 liquid] was prepared in the same manner as in Example 1 except that the composition of Example 1 was changed to the following composition.
Emulsion type tackifier [A-2 liquid] 8.1 parts by mass Thermoplastic resin emulsion (acrylic acid-2-ethylhexyl resin main component, manufactured by Showa Polymer Co., Ltd., AP5570, solid content 55% by mass , Glass transition temperature (Tg) = − 65 ° C.) 8.1 parts by mass Solid plasticizer dispersion [C-3 liquid] 81.8 parts by mass Water 2.0 parts by mass

Example 4
-Preparation of water-dispersed thermosensitive adhesive liquid [E-4 liquid]-
A water-dispersed thermosensitive adhesive solution [A-2] was changed in the same manner as in Example 3 except that the emulsion-type tackifier [A-3] was changed. E-4 solution] was prepared.

(Comparative Example 1)
-Preparation of water-dispersed thermosensitive adhesive liquid [E-5 liquid]-
In Example 1, except that the emulsion type tackifier [A-2 solution] was changed to [A-1 solution], a water-dispersed thermosensitive adhesive solution [E-5] was obtained in the same manner as in Example 1. Liquid] was prepared.

(Comparative Example 2)
-Preparation of water-dispersed thermosensitive adhesive liquid [E-6 liquid]-
In Example 4, except that the emulsion type tackifier [A-2 liquid] was changed to [A-1 liquid], a water-dispersed thermosensitive adhesive liquid [E-6] was obtained in the same manner as in Example 1. Liquid] was prepared.

(Comparative Example 3)
-Preparation of water-dispersed thermosensitive adhesive liquid [E-7 liquid]-
In Example 1, except that the emulsion type tackifier [A-2 liquid] was changed to [A-4 liquid], the same as in Example 1, the water-dispersed thermosensitive adhesive liquid [E-7 Liquid] was prepared.

(Example 5)
<Preparation of heat-sensitive adhesive material>
-Preparation of non-foaming heat insulating layer forming coating solution [F solution]-
A non-foaming heat insulating layer forming coating solution [F solution] 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% by mass, average particle size 3.6 μm, hollowness 92%) 30 parts by mass ・ Styrene-butadiene copolymer Latex (glass transition temperature (Tg) 4 ° C., solid content 48% by mass, manufactured by Nippon A & L Co., Ltd.) ... 10 parts by mass Surfactant (Dapro W-77, manufactured by Elementis Japan) ... 0. 1 part by mass-Water ... 60 parts by mass

-Preparation of color former dispersion [liquid G]-
A mixture of the following composition was dispersed using a sand mill so that the volume average particle diameter was about 1.5 μm to prepare a color former dispersion liquid [G liquid].
・ 3-Di-n-butylamino-6-methyl-7-anilinofluorane: 20 parts by mass ・ Polyvinyl alcohol (10% by mass aqueous solution, manufactured by Nippon Synthetic Chemical Industry Co., Ltd., Goceran L-3266) ... 10 parts by massWater: 70 parts by mass

-Preparation of developer dispersion [liquid H]-
A mixture of the following composition was dispersed using a sand mill so that the volume average particle diameter was about 1.5 μm, to prepare a developer dispersion [Liquid H].
4-isopropoxy-4'-hydroxydiphenylsulfone: 10 parts by mass Polyvinyl alcohol (10% by weight aqueous solution, manufactured by Nippon Synthetic Chemical Industry Co., Ltd., Gocelan L-3266) ... 25 parts by mass Carbonic acid Calcium (Shiraishi Kogyo Co., Ltd., CALSHITEC Brillant-15): 15 parts by mass Water: 50 parts by mass

-Preparation of thermosensitive recording layer coating solution [I solution]-
Next, the mixture [G solution]: [H solution] = 1: 8 (mass ratio) was mixed and stirred to prepare a thermal recording layer coating solution [I solution].

Next, the above [F liquid] was 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 4 g / m ² and dried to provide a non-foaming heat insulating layer. . On top of this, the above [I liquid] was applied so that the mass after drying was 5 g / m ² and dried to provide a heat-sensitive recording layer. Next, the paper was coated with a thermal recording layer by super calendering so that the Oken smoothness was 2,000 seconds.

[Preparation of protective layer coating solution]
-Preparation of protective layer primary dispersion-
A mixture having the following composition was pulverized with a vertical sand mill so that the volume average particle diameter was 1 μm or less, and dispersed to prepare a protective layer primary dispersion.
Aluminum hydroxide (Showa Denko KK, H-42M) 20 parts by mass Polyvinyl alcohol (10% by weight aqueous solution, Nippon Synthetic Chemical Industry Co., Ltd., Gocelan L-3266) 20 parts by mass・ Water ・ ・ ・ 40 parts by mass

Next, a mixture having the following composition was mixed and dispersed to prepare a protective layer coating solution.
-Primary dispersion of protective layer: 10 parts by mass-Polyvinyl alcohol (10% by mass aqueous solution, manufactured by Nippon Synthetic Chemical Industry Co., Ltd., Gocelan L-3266) ... 20 parts by mass-Epichlorohydrin (12.5% by mass) Aqueous solution) ... 5 parts by mass-30% by weight zinc stearate dispersion ... 2 parts by mass

-Production of thermal recording paper-
Next, the protective layer coating solution was applied onto the heat-sensitive recording layer-coated paper so that the dry coating amount was 3.0 g / m ² and dried. Thereafter, super-calender processing was performed so that the Oken type smoothness was 2,000 seconds to prepare a thermal recording paper.
A water-dispersed heat-sensitive adhesive liquid [E-1 liquid] is applied to the surface of the heat-sensitive recording paper that does not have a heat-sensitive recording layer so that the dry adhesion amount is 15 g / m ² and dried. A heat sensitive adhesive layer was formed. Thus, the heat-sensitive adhesive material of Example 5 was produced.

(Example 6)
-Production of heat-sensitive adhesive material-
In Example 5, a heat-sensitive adhesive material was produced in the same manner as in Example 5 except that the water-dispersed thermosensitive adhesive liquid [E-1 liquid] was changed to [E-2 liquid].

(Example 7)
-Production of heat-sensitive adhesive material-
In Example 5, a heat-sensitive adhesive material was produced in the same manner as in Example 5 except that the water-dispersed thermosensitive adhesive liquid [E-1 liquid] was changed to [E-3 liquid].

(Example 8)
-Production of heat-sensitive adhesive material-
In Example 5, a heat-sensitive adhesive material was produced in the same manner as in Example 5 except that the water-dispersed thermosensitive adhesive liquid [E-1 liquid] was changed to [E-4 liquid].

Example 9
-Production of heat-sensitive adhesive material-
A hollow under layer coating solution (D-1 solution) was applied to the surface of the heat-sensitive recording paper prepared in Example 5 that does not have a heat-sensitive recording layer so as to have an adhesion amount of 5 g / m ² and dried. A heat-sensitive adhesive material was prepared in the same manner as in Example 5 except that a heat-sensitive adhesive layer was provided on the hollow underlayer.

(Example 10)
-Production of heat-sensitive adhesive material-
An adhesive under layer coating solution (D-2 solution) was deposited on the surface of the thermal recording paper prepared in Example 5 that does not have a thermal recording layer, and the adhesion amount was 20 g / m ^2, and a hollow under layer coating solution (D -1 liquid) was sequentially applied so as to have an adhesion amount of 2 g / m ² and dried to form a pressure-sensitive adhesive underlayer and a hollow underlayer, and a heat-sensitive pressure-sensitive adhesive material was produced in the same manner as in Example 5. .

(Comparative Example 4)
-Production of heat-sensitive adhesive material-
In Example 5, a heat-sensitive adhesive material was prepared in the same manner as in Example 5 except that the water-dispersed thermosensitive adhesive liquid [E-1 liquid] was changed to [E-5 liquid].

(Comparative Example 5)
-Production of heat-sensitive adhesive material-
In Example 5, a heat-sensitive adhesive material was prepared in the same manner as in Example 5 except that the water-dispersed thermosensitive adhesive liquid [E-1 liquid] was changed to [E-6 liquid].

(Comparative Example 6)
-Production of heat-sensitive adhesive material-
In Example 5, a heat-sensitive adhesive material was prepared in the same manner as in Example 5 except that the water-dispersed thermosensitive adhesive liquid [E-1 liquid] was changed to [E-7 liquid].

Here, the contents of the heat-sensitive adhesive materials of Examples 5 to 10 and Comparative Examples 4 to 6 are summarized and shown in Table 2 below.
* TPP: Triphenylphosphine, manufactured by Hokuko Chemical Co., Ltd. * Eversorb: 2- (2′-hydroxy-3′-t-butyl-5′-methylphenyl) -5-chlorobenzotriazole (trade name: Evesorb73, sort (Made by company)
* Pronox 1222: diethyl [[3,5-bis (1,1-dimethylethyl) -4-hydroxyphenyl] methyl] phosphonate (trade name: PRONOX 1222, manufactured by Sort Co., Ltd.)

  Next, about each heat-sensitive adhesive material of Examples 5-10 and Comparative Examples 4-6, the adhesive characteristic and blocking were evaluated as follows.

<Evaluation of adhesive properties>
Each heat-sensitive adhesive material obtained was cut into a 40 mm × 150 mm rectangle, and using a thermal printing apparatus (manufactured by Okura Electric Co., Ltd., TH-PMD), head conditions: energy 0.50 mJ / dot, printing speed: 4 ms. / Line, platen pressure: The heat-sensitive adhesive sheet was thermally activated under the conditions of 6 kgf / line. Next, after corrugated in a longitudinal direction with a 2 kg pressure rubber roller on a corrugated cardboard that has been left for 1 day under four environmental conditions of 0 ° C., 5 ° C., 22 ° C., and 40 ° C., and stored for 1 day in each temperature environment Peeling was performed under 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 data was read and averaged at intervals of 0.1 seconds. The results are shown in Tables 4 and 5. The unit was N / 40 mm.
The adhesive strength rank was determined by the following determination.
A: 10 N / 40 mm or more (or torn adherend or substrate)
○: 5 N / 40 mm or more Δ: 3 N / 40 mm or more and less than 5 N / 40 mm ×: 3 N / 40 mm or less

<Evaluation of blocking resistance>
The surface opposite to the heat-sensitive adhesive layer surface (heat-sensitive recording layer) of each obtained heat-sensitive adhesive material was brought into contact, applied with a pressure of 200 g / cm ² , and left for 1 day at 60 ° C. under Dry conditions. Then, 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, and the results are shown in Table 4. In the present invention, rank 7 or higher is a practical level.

From the results of Table 4, in Examples 5 to 10, the blocking resistance is improved by using the tackifier having a molecular weight of 300 or less in the molecular weight distribution of the tackifier of 4.2% by mass or less. I found out.

From the results in Table 5, it was found that in Examples 9 and 10, the adhesive strength to cardboard at 0 ° C. was improved by providing an under layer between the heat-sensitive adhesive layer and the support.

  The heat-sensitive adhesive of the present invention has a strong adhesive force to rough surface adherends such as corrugated cardboard, has little decrease in adhesive force over time, can be activated with a thermal head at low energy, and has good blocking resistance. Therefore, it is suitably used for various heat-sensitive adhesive materials.

Claims (10)

At least a thermoplastic resin, a solid plasticizer, and a heat-sensitive adhesive ing contain a tackifier,
The content of the thermoplastic resin in the heat-sensitive adhesive is 10% by mass to 60% by mass,
The content of the solid plasticizer in the heat-sensitive adhesive is 25% by mass to 80% by mass,
The content of the tackifier in the heat-sensitive adhesive is 1% by mass to 30% by mass,
The thermoplastic resin is a (meth) acrylic polymer emulsion;
The solid plasticizer is a compound represented by at least one of structural formula (1) to structural formula (3),
The tackifier is at least one of rosins and rosin derivatives, and the proportion of the component having a molecular weight of 300 or less in the tackifier is 4.2% by mass or less based on the total solid content of the tackifier. A heat-sensitive adhesive, characterized by
However, in the structural formula (1), R ¹ and R ² may be the same as or different from each other, and each represents a hydrogen atom, an alkyl group, or an α, α-dimethylbenzyl group. . X represents either a hydrogen atom or a halogen atom.
Structural formula (2)
The heat-sensitive adhesive according to claim 1, wherein the tackifier has a mass average molecular weight of 1,000 to 3,000. The heat-sensitive adhesive according to any one of claims 1 to 2, wherein the tackifier is a rosin derivative. The heat-sensitive adhesive according to claim 1, wherein the tackifier is a polymerized rosin ester. A heat-sensitive adhesive material comprising a support and a heat-sensitive adhesive layer made of the heat-sensitive adhesive according to claim 1 on the support. The heat-sensitive adhesive material according to claim 5, which has an under layer between the heat-sensitive adhesive layer and the support. The heat-sensitive adhesive material according to claim 6, wherein the under layer is a hollow under layer containing hollow particles. The heat-sensitive adhesive material according to claim 6, wherein the under layer comprises an adhesive under layer and a hollow under layer containing hollow particles . The heat-sensitive adhesive material according to any one of claims 5 to 8, wherein the adhesiveness is exhibited by heating with a line-type thermal head. The heat-sensitive adhesive material according to any one of claims 5 to 9, further comprising a recording layer on the side surface opposite to the surface having the heat-sensitive adhesive layer of the support.