JP2001234151A - Aqueous heat-sensitive adhesive composition, heat-sensitive adhesive sheet, and method for producing heat-sensitive adhesive sheet - Google Patents

Abstract

(57) [Summary] [Problem] After coating, heating and drying can be performed at a higher temperature, and even when stored for a long time, blocking does not occur, and adhesiveness can be exhibited at an activation temperature similar to the conventional one. A water-based heat-sensitive adhesive composition is obtained. SOLUTION: The aqueous heat-sensitive adhesive composition of the present invention is an aqueous heat-sensitive adhesive composition containing a solid plasticizer, a thermoplastic resin and a tackifier, wherein the solid plasticizer has a melting point of 70 ° C or more. Yes, and the softening point of the tackifier is 150 to 180 ° C
It is. As the solid plasticizer, for example, bis (cis-3,
3,5-trimethylcyclohexyl) phthalate and the like can be used. The content of the solid plasticizer is the thermoplastic resin 10
It is about 350 to 800 parts by weight with respect to 0 parts by weight. A heat-sensitive adhesive sheet can be produced by applying the above-mentioned water-based heat-sensitive adhesive composition to at least one surface of a support and providing an adhesive layer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a water-based heat-sensitive adhesive composition for use in so-called delayed tack labels and the like,
The present invention relates to a heat-sensitive adhesive sheet and a method for producing the heat-sensitive adhesive sheet.

[0002]

2. Description of the Related Art Conventionally, as a label to be attached to containers such as glass bottles and PET bottles, a glue label which is applied to a container while simultaneously applying an adhesive on a label base material,
An adhesive label or the like in which an adhesive and a release paper are sequentially formed on a label substrate is used. However, glue labels are not very popular recently because they require time and labor such as management of the viscosity of the adhesive and cleaning of a machine for applying the adhesive. Further, since a large amount of release paper peeled off from the label is generated as garbage, the pressure-sensitive adhesive label on which release paper is formed is troublesome and its disposal is not preferable from the viewpoint of resource saving.

As a label for solving such a problem,
A so-called delayed tack label is known. Delayed tack labels are formed by forming a delayed tack layer (thermosensitive adhesive layer) that is non-adhesive at room temperature but develops adhesiveness on heating on a label base material. It has the advantage that it can be easily affixed to a container simply by doing. The delayed tack layer usually has a glass transition temperature of 0 to 30 ° C.
The thermoplastic resin layer of the degree, the particles of the solid plasticizer and, if necessary, a tackifier are dispersed, and the solid plasticizer is melted by heating, thereby plasticizing the thermoplastic resin and forming an adhesive. Is expressed. Examples of the solid plasticizer are described in JP-A-7-278251 and JP-A-7-17-1.
For example, dicyclohexyl phthalate is well known, and is generally used and put to practical use.

[0004] Recently, the above-mentioned dilatac labels are often manufactured by applying an emulsion-type heat-sensitive adhesive to the back surface of a substrate and then subjecting the substrate to a heating step for drying. The heating temperature in that case is required to be a low temperature of 45 ° C. or less so that dicyclohexyl phthalate does not melt and develop adhesiveness at the stage of forming the adhesive layer. However, such low-temperature heating requires a long time for the heating and drying process, and thus has a problem that the productivity of the delayed tack label is reduced. In addition, since the delayed tack label does not use release paper as described above, if it is stored in a stacked state for a long period of time at a high temperature in summer, for example, the plasticization of the thermoplastic resin by dicyclohexyl phthalate gradually occurs, and the labels come together. Are adhered to each other, so-called blocking occurs. Therefore, there is a problem that a cold insulation facility is required to prevent such blocking.

As a technique for solving the above-mentioned blocking problem, Japanese Patent Publication No. 62-21835 discloses a method of incorporating a wax into a pressure-sensitive adhesive composition. However, this method is not only insufficiently effective but also results in a decrease in tackiness. Japanese Patent Application Laid-Open No. 9-221644 attempts to solve the blocking problem by increasing the softening point temperature of the tackifier incorporated in the pressure-sensitive adhesive composition to 150 to 170 ° C. Is insufficient in blocking resistance, and is insufficient to improve the productivity in the heating and drying step.

Further, in Japanese Patent Application Laid-Open No. 11-269440, an attempt is made to improve the blocking resistance by forming the pressure-sensitive adhesive layer into a two-layer structure. However, multiple steps are required to produce a heat-sensitive pressure-sensitive adhesive sheet. There was a problem of becoming.

Further, in the case of a conventional heat-sensitive adhesive sheet, when printing is performed by an air-cooled UV printer, blocking occurs due to heat generated at the time of printing, so that printing by the printer was impossible.

[0008]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a coating film which can be dried by heating at a higher temperature after coating, has no blocking even when stored for a long period of time, and has an activity comparable to that of the prior art. It is an object of the present invention to provide a water-based heat-sensitive adhesive composition capable of exhibiting tackiness at an activation temperature, a heat-sensitive adhesive sheet having a pressure-sensitive adhesive layer formed of the water-based heat-sensitive adhesive composition, and a method for producing the same. Another object of the present invention is to provide a water-based heat-sensitive adhesive composition which has a strong adhesive strength to a substrate surface in addition to the above properties, and can be applied in one step, and the water-based heat-sensitive adhesive. The object of the present invention is to provide a heat-sensitive adhesive sheet having a pressure-sensitive adhesive layer formed of an agent composition and a method for producing the same. Still another object of the present invention is to provide an air-cooled UV
It is an object of the present invention to provide a water-based heat-sensitive adhesive composition capable of printing by a printing machine, a heat-sensitive adhesive sheet having a pressure-sensitive adhesive layer formed of the water-based heat-sensitive adhesive composition, and a method for producing the same.

[0009]

Means for Solving the Problems The present inventors have made intensive studies to achieve the above object, and as a result, when a solid plasticizer having a specific melting point and a tackifier having a specific softening point are used in combination, The inventors have found that the blocking resistance can be significantly improved, and have completed the present invention. That is, the present invention is an aqueous heat-sensitive adhesive composition containing a solid plasticizer, a thermoplastic resin and a tackifier, wherein the solid plasticizer has a melting point of 7%.
0 ° C. or higher and the softening point of the tackifier is 150 to 1
A water-based heat-sensitive adhesive composition at 80 ° C. is provided. The present invention also provides a heat-sensitive adhesive sheet having a pressure-sensitive adhesive layer formed by applying the above-mentioned water-based heat-sensitive adhesive composition on at least one surface of a support. The present invention further provides a method for producing a heat-sensitive pressure-sensitive adhesive sheet, in which a water-based heat-sensitive pressure-sensitive adhesive composition is coated on at least one surface of a support to form a pressure-sensitive adhesive layer.

[0010]

Embodiments of the present invention will be described below. Examples of the thermoplastic resin used in the present invention include a homo- or copolymer of a (meth) acrylate, a styrene- (meth) acrylate copolymer, and a vinyl acetate- (meth) acrylate copolymer. Copolymer, ethylene- (meth) acrylate copolymer, ethylene- (meth) acrylic acid copolymer, (meth)
Acrylic acid ester- (meth) acrylic acid copolymer, styrene-acrylonitrile- (meth) acrylic acid ester copolymer, styrene- (meth) acrylic acid ester-
(Meth) acrylic acid copolymer, styrene-acrylonitrile- (meth) acrylic acid ester- (meth) acrylic acid copolymer, ethylene-vinyl acetate- (meth) acrylic acid ester copolymer, vinylpyrrolidone- (meth) Acrylic polymer containing (meth) acrylic acid or its ester as a monomer, such as acrylic ester copolymer and styrene-butadiene- (meth) acrylic acid copolymer; vinyl acetate resin, ethylene-vinyl acetate copolymer A vinyl acetate polymer containing vinyl acetate as a monomer, such as a copolymer; styrene-butadiene copolymer, isobutylene resin, isobutylene-isoprene copolymer, butadiene resin, styrene-isoprene copolymer, acrylonitrile-butadiene copolymer Synthetic rubber such as; natural rubber; ethylene-vinyl chloride copolymer; Vinyl - copolymer vinylidene chloride polymer, vinylpyrrolidone - styrene copolymer, a chlorinated propylene resins, urethane resins, ethyl cellulose, and the like. These thermoplastic resins may be used alone or in combination of two or more.

Among these, acrylic polymers [for example,
For example, an adhesive containing (meth) acrylic acid ester as a monomer
Kuryl polymer], vinyl acetate polymer, synthetic rubber, heavenly
Natural rubber is preferred. Further, the acrylic polymer
Among them, particularly, acrylate-methacrylic acid ester
Ter copolymer (for example, acrylic acid C_2-20Alkyl S
Ter-methacrylic acid C_1-4Alkyl ester copolymerization
Body), acrylate-methacrylate-
(Meth) acrylic acid copolymer (for example, acrylic acid C
_2-20Alkyl ester-methacrylic acid C_1-4Alkyle
Ste- (meth) acrylic acid copolymer), acrylic acid
Stele-styrene- (meth) acrylic acid copolymer (eg,
For example, acrylic acid C_2-20Alkyl ester-styrene-
Acrylic esters such as (meth) acrylic acid copolymer)
(For example, acrylic acid C_2-20Alkyl esters) and meta
Crylate esters (for example, methacrylic acid C_1-4Archi
Ester) or styrene as a comonomer.
A cryl copolymer is preferred.

Glass transition temperature (Tg) of thermoplastic resin
Can be appropriately selected in consideration of the type of the adherend and the like in a range that does not impair the adhesiveness and the blocking resistance when the pressure-sensitive adhesive sheet is used, and is usually about −10 to 70 ° C., preferably 0 to 5 ° C.
It is about 0 ° C. If the glass transition temperature is too low, the blocking resistance tends to decrease. On the other hand, if the glass transition temperature is too high, the film formation during heating and drying when forming the heat-sensitive adhesive layer tends to be insufficient, and the adhesiveness tends to decrease.

In the present invention, the solid plasticizer has a melting point of 70%.
C. or higher (preferably 80.degree. C. or higher) is used. The upper limit of the melting point can be appropriately set in consideration of the operability at the time of melting and the like, and varies depending on the material of the support and the like.
80 ° C, preferably 160 ° C, more preferably 120 ° C
° C (particularly 100 ° C). Solid plasticizers can be used alone or in combination of two or more.

The type of the solid plasticizer is not particularly limited as long as it satisfies the above-mentioned melting point conditions.
A polyester compound of a hydroxy compound (particularly, a monohydroxy compound) and a polybasic acid (including a dibasic acid), (i
i) ester compound (monoester or polyester compound) of polyhydroxy compound (including dihydroxy compound) and organic monobasic acid (aliphatic, alicyclic or aromatic monocarboxylic acid, etc.), (iii) phosphate ester , Phosphites, phosphines, and other phosphorus compounds.

Representative examples of the (i) polyester compound of a hydroxy compound and a polybasic acid include, for example, diphenyl phthalate (melting point: 73 ° C.), bis (dimethylcyclohexyl) phthalate (melting point: 94 ° C.), Menthol phthalate (melting point: 134 ° C), dibornyl phthalate (melting point: 136 ° C), bis (t-butylcyclohexyl) phthalate (melting point: 103,150 ° C), bis (cis-3,3,5-trimethylcyclohexyl) Phthalates such as phthalate (melting point: 93 ° C); bis (cis-3,3,5-trimethylcyclohexyl) terephthalate (melting point: 133 ° C), bis (trans-3,
3,5-trimethylcyclohexyl) terephthalate (melting point: 103 ° C.), bis (dimethylcyclohexyl)
And terephthalic acid esters such as terephthalate (melting point: 89 ° C.).

Representative examples of the ester compound (ii) of the polyhydroxy compound and the organic monobasic acid include carboxylic acid esters of polyhydric alcohols such as sucrose benzoate (melting point: 98 ° C.); A benzene ring such as acetate (melting point: 123 ° C.), trimethylhydroquinone diacetate (melting point: 109 ° C.), 3,4,5-trimethylcatechol diacetate (melting point: 120 ° C.) may be substituted with an alkyl group. Examples include hydroquinone, resorcinol, and diester compounds of catechol in which a benzene ring is substituted with an alkyl group and an organic monobasic acid.

Representative examples of the above (iii) phosphorus compounds include, for example, 1,4-cyclohexanedimethanolbis (diphenylphosphate) (melting point: 97 ° C.), resorcinol bis [di (2,6-dimethylphenyl) phosphate ] (Melting point: 95 ° C), tri (4-methylphenyl) phosphate (melting point: 78 ° C), tri (4-t-butylphenyl) phosphite (melting point: 75 ° C), triphenylphosphine (melting point: 80 ° C) And tri (3-methylphenyl) phosphine (melting point: 100 ° C.).

Among the above-mentioned solid plasticizers, (i) a polyester compound of a hydroxy compound and a polybasic acid is preferable. In particular, an alicyclic carbon ring (cycloalkane ring, cycloalkene ring, bridged ring, etc.) is preferably used. A polyester compound of an alcohol having the same and a polybasic acid such as an aromatic polycarboxylic acid (phthalic acid, terephthalic acid, isophthalic acid, etc.) is preferred. Such a polyester compound can be produced from the alcohol and the polybasic acid or a reactive derivative thereof (eg, acid anhydride, acid halide, active ester, etc.) by utilizing a known or common esterification method. . For example, the desired polyester compound can be obtained by reacting the alcohol with a polybasic acid in a toluene solvent at a predetermined temperature in the presence of a protonic acid catalyst and removing generated water.

Among the above-mentioned polyester compounds (i), particularly effective solid plasticizers include polyesters obtained from 3,3,5-trimethylcyclohexanol (particularly cis-3,3,5-trimethylcyclohexanol). Compounds include, for example, bis (cis-3,3,5-trimethylcyclohexyl) phthalate (melting point: 93 ° C.).

The 3,3,5-trimethylcyclohexanol has two geometrical isomers, a cis form and a trans form, depending on the steric positional relationship between the hydroxyl group and the methyl group at the 5-position. In the present invention, a polyester compound obtained from any of these isomers can be used as long as the above-mentioned melting point condition is satisfied, and a polyester compound obtained from a mixture of these isomers can be used. You can also.

In the present invention, the content of the solid plasticizer in the water-based heat-sensitive adhesive composition is generally about 350 to 800 parts by weight, preferably 400 to 700 parts by weight, based on 100 parts by weight of the thermoplastic resin. It is about. If the amount of the solid plasticizer is too small, sufficient blocking resistance may not be easily obtained, and if it is too large, the cohesive strength may be reduced and sufficient adhesive strength may not be exhibited.

In the present invention, the tackifier has a softening point of 1
Use the one of 50 to 180 ° C. If the softening point is lower than 150 ° C., blocking is very likely to occur, and if the softening point is higher than 180 ° C., the activation temperature is undesirably high. The type of the tackifier is not particularly limited as long as the softening point is in the above range.For example, terpene resin, aliphatic petroleum resin, aromatic petroleum resin, cumarone-indene resin, styrene resin, phenol resin, Resins such as terpene-phenol resins, rosin derivatives (rosin, polymerized rosin, hydrogenated rosin and their esters with glycerin, pentaerythritol, etc., resin acid dimers, etc.) and xylene resins can be used. Adjustment of the softening point, for example,
It can be carried out by appropriately selecting the molecular weight and molecular weight distribution of the resin, the ratio between the low molecular weight component and the high molecular weight component, and the like. Two or more of these tackifiers may be used in combination.

The content of the tackifier in the water-based heat-sensitive adhesive composition is appropriately determined according to the combination of the thermoplastic resin and the solid plasticizer.
The amount is about 100 to 500 parts by weight, more preferably about 120 to 400 parts by weight based on parts by weight.

The water-based heat-sensitive adhesive composition of the present invention may contain, in addition to the tackifier described above, conventional additives such as film-forming aids, defoamers, and coatability improvers as long as the properties are not impaired. , Thickeners, lubricants, stabilizers (antioxidants, ultraviolet absorbers, heat stabilizers, etc.), antistatic agents, antiblocking agents (inorganic particles,
Organic particles).

Examples of the film-forming auxiliary include ethylene glycol mono n-butyl ether, dipropylene glycol monomethyl ether acetate, diethylene glycol mono n-butyl ether, propylene glycol mono n-butyl ether, ethylene glycol monophenyl ether, and propylene glycol monophenyl. Ether, ethylene glycol mono 2-ethylhexyl ether, propylene glycol diacetate, 2,2,4
Glycol ethers and glycol esters such as trimethyl-1,3-pentanediol monoisobutyrate and 2,2,4-trimethyl-1,3-pentanediol diisobutyrate; dibutyl phthalate, dioctyl phthalate, sebacine Carboxylic acid diesters such as dioctyl acid; and organic solvents such as benzyl alcohol, toluene, acetone, methanol, ethanol, n-propanol, isopropanol, butanol, n-hexane and cyclohexane. These film-forming auxiliaries may be used alone or in combination of two or more.

The water-based heat-sensitive adhesive composition of the present invention can be prepared by various conventionally known methods. For example, as a method for preparing the aqueous heat-sensitive adhesive composition, a method in which the components constituting the aqueous heat-sensitive adhesive composition are mixed in advance and then dispersed in water, and a solid plasticizer is added to the thermoplastic resin emulsion or the tackifier emulsion. And a method in which these emulsions are mixed after dispersing, a method in which a solid plasticizer is dispersed in water, and a thermoplastic resin emulsion and a tackifier emulsion are mixed with the aqueous dispersion of the solid plasticizer. Examples of the method of dispersing the solid plasticizer in the above-mentioned emulsion or water include a method of dispersing a molten solid plasticizer, a method of dispersing a solid plasticizer while making it into a fine powder, and a method of dispersing a solid plasticizer that is made into a fine powder. Can be exemplified.

The above-mentioned thermoplastic resin emulsion may be prepared by emulsion polymerization. Alternatively, after obtaining a polymer by a method other than emulsion polymerization, the emulsion may be prepared by using an additive as necessary. Is also good. For example, after an additive (eg, an emulsifier, a pH adjuster, an acid, etc.) is added to an organic solution containing a polymer polymerized in the presence of a water-soluble organic solvent (eg, an alcohol such as isopropyl alcohol), water is added. Is added to form an emulsion, and then the organic solvent is removed to prepare a thermoplastic resin emulsion.

The average particle size of the solid plasticizer in the water-based heat-sensitive adhesive composition is preferably about 0.5 to 20 μm, and more preferably about 1 to 15 μm. If the average particle size is smaller than 0.5 μm, the blocking resistance may decrease, or the pulverization may require time to lower the productivity. If the average particle size exceeds 20 μm, the coated surface may be rough and the quality of the label may be degraded.

The heat-sensitive adhesive sheet of the present invention is obtained by applying the above-mentioned aqueous heat-sensitive adhesive composition on at least one surface of a support to form a heat-sensitive adhesive layer (delayed tack adhesive layer). Can be manufactured.

As the support (substrate) of the heat-sensitive adhesive sheet of the present invention, for example, coated paper, plastic film, wood, cloth, nonwoven fabric, metal and the like can be used. Examples of the polymer constituting the plastic film include polyolefins such as polyethylene and polypropylene, ethylene-vinyl acetate copolymer, polyvinyl chloride, polyvinyl chloride-vinyl acetate copolymer, poly (meth) acrylate, polystyrene, and the like. Polyvinyl alcohol, ethylene-vinyl alcohol copolymer, cellulose derivatives such as cellulose acetate, polyester (polyalkylene terephthalate such as polyethylene terephthalate and polybutylene terephthalate, polyalkylene naphthalate such as polyethylene naphthalate and polybutylene naphthalate), polycarbonate , Polyamide (polyamide 6, polyamide 6/6, polyamide 6/10, polyamide 6/12, etc.), polyester amide, polyether, polyimide, poly Examples thereof include amide imides and polyether esters, and copolymers, blends and cross-linked products thereof may be used.

As a method for applying the water-based heat-sensitive adhesive composition, for example, a method using a roll coater, an air knife coater, a blade coater, a rod coater, a bar coater, a comma coater, a gravure coater, a silk screen coater or the like is used. Can be mentioned. The heat-sensitive adhesive layer can also be formed by printing using a gravure printing machine or the like. The coating amount of the heat-sensitive adhesive layer is, for example, 4 to
20 g / m ^2, preferably from 5 to 15 g / m ² approximately.
If the thickness of the pressure-sensitive adhesive layer is too small, it will be difficult to obtain a sufficient adhesive function when used as a label. On the other hand, if the thickness of the pressure-sensitive adhesive layer is too large, it takes more time to develop the adhesiveness.

The heat-sensitive adhesive sheet of the present invention is suitably used as a label to be attached to containers such as bottles and PET bottles.

[0033]

According to the present invention, since a solid plasticizer having a melting point of 70 ° C. or more and a tackifier having a high softening point of 150 to 180 ° C. are combined, after application, heat drying is performed at a higher temperature. In addition to this, no blocking occurs even when stored for a long period of time, and at the same activation temperature as before, tackiness is developed. In addition, it has a strong adhesive strength to the substrate surface, and can provide a heat-sensitive adhesive layer by one-step coating. In addition, even when a printing layer is provided on the back surface of the base material by gravure printing or the like, rapid heating and drying can be performed at a higher temperature, and printing using an air-cooled UV printer, which has been impossible so far, is also possible. Therefore, the production efficiency of labels and the like using the heat-sensitive adhesive sheet is greatly improved.

[0034]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to the following Examples. The average particle size of the solid plasticizer was measured using a laser diffraction particle size distribution analyzer (LA-500, manufactured by HORIBA, Ltd.)
And reported as a median diameter.

Example 1 (Preparation of aqueous dispersion of solid plasticizer) 100 parts by weight of bis (cis-3,3,5-trimethylcyclohexyl) phthalate (melting point 93 ° C.) as a solid plasticizer and an anionic interface as a dispersant Activator (polycarboxylic acid ammonium salt) 1
5 parts by weight and 80 parts by weight of water are mixed and pulverized using a ball mill until the average particle diameter becomes 2.2 μm, whereby an aqueous dispersion of bis (cis-3,3,5-trimethylcyclohexyl) phthalate is obtained. Was. (Preparation of heat-sensitive adhesive composition) An acrylic polymer (2-ethylhexyl acrylate) as a thermoplastic resin was added to the aqueous dispersion of bis (cis-3,3,5-trimethylcyclohexyl) phthalate prepared above. Styrene-acrylic acid copolymer, water-based emulsion having a glass transition temperature Tg: 25 ° C), and a softening point as a tackifier of 160 ° C
And a water-based dispersion of rosin resin and water were added, and the mixture was stirred until it became uniform to obtain a heat-sensitive adhesive composition having a solid content of 50% by weight. At this time, the mixing ratio was 17 parts by weight of the thermoplastic resin and 26 parts by weight of the tackifier with respect to 100 parts by weight of the solid plasticizer [bis (cis-3,3,5-trimethylcyclohexyl) phthalate]. (Thermosensitive pressure-sensitive adhesive sheet) A polyethylene terephthalate film (hereinafter, referred to as a base paper surface of a single art paper having a basis weight of 102.3 g / m ² and a corona discharge treatment having a thickness of 25 μm) was prepared from the heat-sensitive adhesive composition prepared above. (Hereinafter simply referred to as “PET film”) using a bar coater so that the coating amount after drying is 10 g / m ² ,
After drying for minutes, a heat-sensitive adhesive sheet was obtained.

Example 2 (Preparation of aqueous dispersion of solid plasticizer) An aqueous dispersion of solid plasticizer was prepared in the same manner as in Example 1. (Preparation of heat-sensitive adhesive composition) As a water-based emulsion of a thermoplastic resin, a water-based emulsion of an acrylic polymer (2-ethylhexyl acrylate-styrene-acrylic acid copolymer, glass transition temperature Tg: 15 ° C) was used. Except for the above, a heat-sensitive adhesive composition was prepared in the same manner as in Example 1. (Production of heat-sensitive adhesive sheet) A heat-sensitive adhesive sheet was produced in the same manner as in Example 1.

Example 3 (Preparation of an aqueous dispersion of a solid plasticizer) An aqueous dispersion of a solid plasticizer was prepared in the same manner as in Example 1. (Preparation of Thermosensitive Adhesive Composition) As a water-based emulsion of a thermoplastic resin, a water-based emulsion having a rubber-based resin SBR0589 [manufactured by Nippon Synthetic Rubber Co., Ltd., glass transition temperature Tg: 8 ° C. (actual value)] was used. Except for the above, a heat-sensitive adhesive composition was prepared in the same manner as in Example 1. (Production of heat-sensitive adhesive sheet) A heat-sensitive adhesive sheet was produced in the same manner as in Example 1.

Comparative Example 1 (Preparation of aqueous dispersion of solid plasticizer) An aqueous dispersion of solid plasticizer was prepared in the same manner as in Example 1. (Preparation of heat-sensitive adhesive composition) A heat-sensitive adhesive composition was prepared in the same manner as in Example 1 except that a rosin resin having a softening point of 125 ° C was used as a tackifier. (Production of heat-sensitive adhesive sheet) A heat-sensitive adhesive sheet was produced in the same manner as in Example 1.

Comparative Example 2 (Preparation of aqueous dispersion of solid plasticizer) An aqueous dispersion of solid plasticizer was prepared in the same manner as in Example 1. (Preparation of heat-sensitive adhesive composition) A heat-sensitive adhesive composition was prepared in the same manner as in Example 1 except that a terpene resin having a softening point of 140 ° C was used as a tackifier. (Production of heat-sensitive adhesive sheet) A heat-sensitive adhesive sheet was produced in the same manner as in Example 1.

Comparative Example 3 (Preparation of aqueous dispersion of solid plasticizer) As a solid plasticizer, 100 parts by weight of dicyclohexyl phthalate (melting point: 65 ° C.)
An aqueous dispersion of dicyclohexyl phthalate is obtained by mixing 15 parts by weight of an anionic surfactant (polycarboxylic acid ammonium salt) and 80 parts by weight of water as a dispersant, and pulverizing the mixture with a ball mill until the average particle diameter becomes 2.2 μm. A liquid was obtained. (Preparation of heat-sensitive adhesive composition) A heat-sensitive adhesive composition was prepared in the same manner as in Example 1, except that the aqueous dispersion of dicyclohexyl phthalate prepared above was used as the aqueous dispersion of the solid plasticizer. (Production of heat-sensitive adhesive sheet) A heat-sensitive adhesive sheet was produced in the same manner as in Example 1.

Performance Test (Adhesion Strength) A heat-sensitive adhesive sheet obtained by coating a PET film was cut into a size of 25 mm in width and 125 mm in length to obtain a test piece. The test piece was heated at 120 ° C. for 30 seconds to develop adhesiveness, and a glass plate [Iwaki Glass Co., Ltd.
(Micro S1ide G1ass, white-green polishing) manufactured by the company, and affixed by two reciprocations under a load of 2 kg with a rubber roll. This was left in an atmosphere of 23 ° C. and 50% RH for one day, and then, using a tensile tester (manufactured by Orientec, Tensilon UCT-5T), a tensile speed of 300 mm /
The adhesive force was measured at a peel angle of 180 ° for one minute. The results are shown in Table 1.

(Blocking resistance) The glossy surface (front surface) of the art paper of four heat-sensitive adhesive sheets obtained by coating on one side art paper is in contact with the surface (rear surface) coated with the heat-sensitive adhesive. And apply a load of 555 g / cm ² to 60 ° C
After standing for 24 hours in the atmosphere described above, the anti-blocking property was evaluated according to the following criteria. The results are shown in Table 1. 5: Peeled without peeling resistance. 4: Peeling was performed with a slight sound when peeling. 3: Peeling was performed while making continuous sound during peeling. 2: Some paper fibers remained in the adhesive layer at the time of peeling. 1: The paper was torn around due to blocking. 0: The whole surface adhered due to blocking, and the paper was broken.

(Real machine heat resistance) The coated surface of the heat-sensitive adhesive sheet obtained by coating on a piece of art paper was overlapped with the glossy surface of the art paper, and a printing test was performed with an air-cooled UV printer, which occurred during printing. The following criteria were used to evaluate whether blocking occurs due to the heat applied. The results are shown in Table 1. ：: No blocking occurred. ×: Adhered to the stacked art paper due to blocking.

[0044]

[Table 1] As is clear from Table 1, the heat-sensitive adhesive sheets of the examples are excellent in both the adhesive strength and the blocking resistance. Further, according to the heat-sensitive adhesive sheet of the example, printing by an air-cooled UV printer, which has been impossible in the field of delayed tack glue, becomes possible.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4J004 AA04 AA05 AA06 AA07 AA09 AA10 AA11 AA12 AA14 AA17 AB01 CA02 CA03 CA04 CA06 CA08 CB01 CC02 FA01 4J040 BA202 CA011 CA051 DB032 DE021 DF041 DF051 H032B03H032B03H DNB032H HD24 HD27 JA03 JA09 JB08 JB11 KA26 KA31 LA02 LA11 NA06 PA18

Claims (7)

[Claims] 1. A water-based heat-sensitive adhesive composition comprising a solid plasticizer, a thermoplastic resin and a tackifier, wherein the melting point of the solid plasticizer is 70 ° C. or higher and the softening point of the tackifier is 150 or more. A water-based heat-sensitive adhesive composition having a temperature of from 180 to 180 ° C. 2. The solid plasticizer comprises (i) a polyester compound of a hydroxy compound and a polybasic acid, (ii) an ester compound of a polyhydroxy compound and an organic monobasic acid, and (ii)
The water-based heat-sensitive adhesive composition according to claim 1, wherein i) at least one component selected from phosphorus compounds. 3. The water-based heat-sensitive adhesive according to claim 2, wherein (i) the polyester compound of the hydroxy compound and the polybasic acid is a polyester compound of an alcohol having an alicyclic carbon ring and the polybasic acid. Composition. 4. A polyester compound of an alcohol having an alicyclic carbon ring and a polybasic acid, wherein the polyester compound is bis (cis-3,3,5-
4. Trimethylcyclohexyl) phthalate.
The water-based heat-sensitive adhesive composition as described in the above. 5. A thermoplastic resin having a solid plasticizer content of 10%.
The amount is 350 to 800 parts by weight with respect to 0 parts by weight.
5. The water-based heat-sensitive adhesive composition according to any one of Items 4 to 4. 6. The method according to claim 1, wherein at least one surface of the support is provided.
A heat-sensitive adhesive sheet having a pressure-sensitive adhesive layer formed by applying the water-based heat-sensitive adhesive composition according to any one of the above items. 7. The method according to claim 1, wherein at least one surface of the support is provided.
A method for producing a heat-sensitive adhesive sheet, comprising applying the water-based heat-sensitive adhesive composition according to any one of the above items to provide an adhesive layer.