JPH0978043A - Preservation of heat-sensitive tacky agent and production of heat-sensitive tacky sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a heat-sensitive tacky sheet having excellent properties hardly precipitating or aggregating of a specific tacky agent component, so- called standing stability even in preserving for a long period of time and capable of stably producing the heat-sensitive tacky sheet. SOLUTION: The preserving method of a heat-sensitive tacky agent comprises to make Brookfield viscosity of the heat-sensitive tacky agent at 25 deg.C 2,000-100,000cps (at 6rpm) in reserving a heat-sensitive tacky agent mainly comprising a thermoplastic resin and a solid plasticizer. Otherwise, Brookfield viscosity of the heat-sensitive tacky agent at 25 deg.C is made to be 2,000-30,000cps (at 6rpm) in production of the heat-sensitive tacky sheet by applying the heat- sensitive tacky agent mainly comprising a thermoplastic resin and a solid plasticizer on one face of a base material and drying the tacky agent.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a heat-sensitive adhesive sheet which is non-adhesive at room temperature but exhibits adhesiveness when heated.

[0002]

2. Description of the Related Art Conventionally, labels such as soft drinks, alcoholic beverages, and glass bottles such as chemical bottles are labeled with a water-soluble adhesive such as casein or starch on the back surface of a substrate by an automatic labeler or the like. There is adopted a method of attaching, or a method of attaching a label of a general adhesive sheet having a structure in which a top paper, an adhesive layer and a release sheet are sequentially laminated using an automatic labeler or the like. However, for a label with a water-soluble adhesive, when the water-soluble adhesive is applied to the back surface of the base material, the label curls and wrinkles or floats occur on the label after it is attached to the glass bottle, resulting in a defective label and spoiling its appearance. There was a problem. On the other hand, a label of a pressure-sensitive adhesive sheet having a general structure is usually used by peeling off the release sheet, but the peeled release sheet is difficult to collect and reuse, and is almost always discarded. In recent years, attention has been paid to resource saving and environmental problems, and a heat-sensitive adhesive sheet that does not require a release sheet has been receiving attention.

Generally, a heat-sensitive adhesive sheet has a structure in which a heat-sensitive adhesive is applied on one surface of a base material, and is usually used as a label by printing on the other surface of the base material. The heat-sensitive adhesive is non-adhesive at room temperature, but is activated and develops adhesiveness when heated with a labeler or an oven provided with a heating device. Usually the activation temperature is between 50 ° C and 150 ° C
In this temperature range, the solid plasticizer in the heat-sensitive adhesive starts to melt and gives the thermoplastic resin an adhesive property. The melted solid plasticizer is crystallized slowly and the stickiness is maintained for a long time. Therefore, it is used by sticking it to a glass bottle or the like while having the stickiness.

Even if the heat-sensitive adhesive sheet is continuously stuck to the glass bottle with a labeler or the like provided with a heating device, it is like a method of applying a water-soluble adhesive to the back surface of the label and sticking it to the glass bottle. There is no problem of a bad label. In addition, there is an advantage that the release sheet is not used unlike the general pressure-sensitive adhesive sheet described above, and thus it can be produced at a low cost.
It is also advantageous from the viewpoint of resource saving and environmental problems.

However, the heat-sensitive adhesive sheet is often stored in a wound state or in a state where several sheets are stacked, and in this case, blocking occurs when the temperature is higher than room temperature. There is a problem. Normally, the solid plasticizer is present in the state of being exposed on the surface of the heat-sensitive adhesive, and when storing it in the state of winding or stacking multiple sheets, the surface of the heat-sensitive adhesive and the printed surface are It has an effect of preventing a certain substrate surface from adhering. For example, a method of preventing blocking by increasing the average particle size of the solid plasticizer of the heat-sensitive adhesive (JP-A-62-1)
No. 64777) has been proposed.

However, if the average particle size of the solid plasticizer is increased, a new problem arises that it becomes difficult to produce a heat-sensitive adhesive sheet with stable quality. This is because when the heat-sensitive adhesive is stored for a long period of time, a specific adhesive component precipitates and begins to aggregate. When a pressure-sensitive adhesive in which such a specific pressure-sensitive adhesive component is precipitated or aggregated is applied to a substrate, the composition ratio of the pressure-sensitive adhesive changes or the specific pressure-sensitive adhesive component is unevenly distributed in the pressure-sensitive adhesive coating layer. . Even when the pressure-sensitive adhesive component does not settle or aggregate, the same phenomenon may occur when the pressure-sensitive adhesive is applied to the substrate. As a result, the heat-sensitive pressure-sensitive adhesive layer does not become a uniform layer, leading to a decrease in adhesive strength, and the desired quality cannot be obtained. It is considered that these problems are due to the use of solid plasticizers having an average particle diameter of 2 μm or more.

[0007]

DISCLOSURE OF THE INVENTION The present invention provides stable production of a heat-sensitive adhesive sheet, which is excellent in the property that a specific adhesive component is unlikely to settle or agglomerate even when stored for a long period of time, so-called stationary stability. The present invention provides a method for producing a heat-sensitive adhesive sheet that enables the above.

[0008]

Means for Solving the Problems As a result of intensive studies on the heat-sensitive adhesive, the present inventors have found that by adjusting the viscosity of the heat-sensitive adhesive to a specific range, it can be stored for a long period of time. When the heat-sensitive adhesive is applied to the base material, it is possible to prevent the specific pressure-sensitive adhesive component from being settled, aggregated, or unevenly distributed, and moreover, it is possible to easily apply the heat-sensitive adhesive to the base material. I found a thing.

According to the present invention, in storing a heat-sensitive adhesive containing a thermoplastic resin and a solid plasticizer as main components, the Brookfield viscosity at 25 ° C. of the heat-sensitive adhesive is 200.
It is a method of storing a heat-sensitive adhesive which is adjusted to 0 to 100,000 cps (6 rpm).

Further, the present invention provides a method for producing a heat-sensitive adhesive sheet, which comprises applying a heat-sensitive adhesive containing a thermoplastic resin and a solid plasticizer as main components to one surface of a substrate and drying the heat-sensitive adhesive. And a Brookfield viscosity at 25 ° C. of 2000 to 30,000 cps (6 rpm). Preferred is a method for producing a heat-sensitive adhesive sheet in which the Brookfield viscosity of the heat-sensitive adhesive at 25 ° C. is 3000 to 15000 cps (6 rpm).

Further, in a method for producing a heat-sensitive adhesive sheet, which comprises applying a heat-sensitive adhesive containing a thermoplastic resin and a solid plasticizer as main components to one surface of a substrate and drying the same, the heat-sensitive adhesive at 25 ° C. Brookfield viscosity of 15,000-
A heat-sensitive adhesive sheet characterized in that it is applied at 100,000 cps (6 rpm) at a temperature below the melting point of the solid plasticizer and at a Brookfield viscosity of 3,000 to 15,000 cps (6 rpm). Is a manufacturing method. Preferred is a method for producing a heat-sensitive adhesive sheet, in which the heating is performed at a temperature of 50 ° C. or lower.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The first aspect of the present invention is characterized in that when the heat-sensitive adhesive is stored, the Brookfield viscosity at 25 ° C. is adjusted to be in the range of 2000 to 100000 cps under the condition of 6 rpm. By the way, 2000c
When it is less than ps, the solid plasticizer precipitates and starts coagulation, and the pressure-sensitive adhesive composition does not have a stable pressure-sensitive adhesive composition ratio,
The heat-sensitive pressure-sensitive adhesive sheet obtained by coating the base material has poor adhesive strength and poor quality. On the other hand, when the viscosity is 10
When the viscosity is higher than 0000 cps, not only is it difficult to prepare and handle the heat-sensitive adhesive composition,
Since it is necessary to add a large amount of a material for increasing the viscosity, that is, a so-called thickener, the adhering adequacy of the pressure-sensitive adhesive is deteriorated (the adhesive strength is lowered). In the present invention, when the heat-sensitive adhesive is stored, a uniform heat-sensitive adhesive sheet can be obtained by adjusting the viscosity range as described above.

A second aspect of the invention is to apply a heat-sensitive adhesive having a thermoplastic resin and a solid plasticizer as main components to one surface of a base material,
In the method for producing a heat-sensitive adhesive sheet for drying, the Brookfield viscosity at 25 ° C. of the heat-sensitive adhesive is 6
The method for producing a heat-sensitive adhesive sheet is characterized in that it is 2000 to 30,000 cps under the condition of rpm. Incidentally, if it is less than 2000 cps, the heat-sensitive adhesive sheet with poor quality such as insufficient adhesive strength as described above will be obtained. Also, since the solid plasticizer tends to settle even at less than 3000 cps, the heat-sensitive adhesive composition may be prepared to have a viscosity of 2000 cps or more, preferably 3000 cps or more. On the other hand, when the viscosity exceeds 30,000 cps, the pressure-sensitive adhesive composition has a stable pressure-sensitive adhesive composition ratio, but it is difficult to apply it to the substrate due to its high viscosity, and the obtained heat-sensitive pressure-sensitive adhesive sheet is homogeneous. Is not obtained and the quality is poor. If it exceeds 15,000 cps, the application tends to be difficult. Therefore, when applying the heat-sensitive adhesive composition, the content of the heat-sensitive adhesive composition is 30,000 cps or less, preferably 15 cps or less.
It may be prepared by diluting to a viscosity range of 000 cps or less.

A third invention is 15,000 to 1,000 under the condition that the Brookfield viscosity at 25 ° C. is 6 rpm.
A thermosensitive adhesive composition of 00 cps was used, and the Brookfield viscosity was 6 in the range below the melting point of the solid plasticizer.
It is characterized in that it is heated to a temperature of 3000 to 15000 cps at rpm, applied in a state satisfying the viscosity range, and dried. In the second invention, 15000 to 300
When a viscosity range of 00 cps (25 ° C., 6 rpm) is applied, a heat-sensitive adhesive sheet with excellent quality can be obtained, but with this viscosity, application to a substrate is slightly difficult.
Further, if it exceeds 30,000 cps (25 ° C., 6 rpm), the viscosity is high and coating cannot be performed, and a heat-sensitive adhesive sheet cannot be obtained. However, in the third invention, it is in such a viscosity range. Also in the range of the melting point of the solid plasticizer or lower, preferably in the temperature range of 50 ° C. or lower, and the Brookfield viscosity of 3000 to 15000 at 6 rpm.
Heat treated to a temperature of cps, 3000 to 1500
It is applied and dried in a viscosity state of 0 cps.

The heating temperature range is defined as a region below the melting point of the solid plasticizer, because when the temperature of the heat-sensitive adhesive is higher than the melting point of the solid plasticizer, the solid plasticizer melts and the heat-sensitive adhesive is melted. This is because the layer becomes tacky. Also, if you continue to heat the heat-sensitive adhesive for a long time,
It may be dried before being applied to the base material, and a part of it may become solid foreign matter and be mixed into the heat-sensitive adhesive, which may make it difficult to obtain a uniform coated surface. Heating in the area is particularly preferred. The Brookfield viscosity at 25 ° C is 100,000 at 6 rpm.
When it exceeds cps, as described above, the heat-sensitive adhesive composition becomes difficult to handle due to its high viscosity, and it is necessary to use a large amount of a component for increasing viscosity, a so-called thickener.
The adhesive strength will be reduced.

As a method for adjusting the viscosity of the heat-sensitive adhesive, a material for increasing the viscosity (thickener) may be added. For example, beidellite, hectorite, montmorillonite, bentonite, saponite, magnesium carbonate, silicon oxide, Inorganic pigments such as mica and alumina, fibrin derivatives such as carboxymethylcellulose, methylcellulose and hydroxymethylcellulose, proteins such as casein, sodium caseinate and ammonium caseinate, polyurethane polymers, alginic acid polymers, polyacrylic acid polymers , Polyvinyl alcohol, polyvinyl pyrrolidone, polyvinyl ether maleic acid, polyvinyl benzyl ether copolymer and other polyvinyl polymers,
Pluronic polyethers, polyether polycarboxylic acids, polyether dialkyl esters, polyether dialkyl ethers, polyether urethane modified products, polyether epoxy modified products, and other polyether polymers are used. Among them, hectorite, bentonite, carboxymethyl cellulose, hydroxymethyl cellulose, polyurethane-based polymer, polyacrylic acid-based polymer, polyether polycarboxylic acid, polyvinyl ether maleic acid, and polyether urethane modified product have a high thickening effect and an adhesive function. Is preferable because the decrease in These materials may be prepared individually or in combination so as to have a specific viscosity. Depending on the type of thickener, if too much is added, the adhesive function may deteriorate, so excessive addition should be avoided as much as possible so as not to impair the function of the heat-sensitive adhesive. Although the compounding ratio of the thickener is largely different depending on the type of the thickener used, it cannot be limited, but it is about 0.05 to 50 solid parts by weight relative to 100 solid parts by weight of the thermoplastic resin.

The types of thermoplastic resins used in the heat-sensitive adhesive of the present invention include vinyl acetate-ethylene-styrene copolymer, vinyl acetate-ethylene copolymer, vinyl acetate-ethylene-vinyl chloride copolymer. , Vinyl acetate-acrylic acid ester copolymer, vinyl acetate-ethylene-acrylic acid ester copolymer, ethylene-vinyl chloride copolymer, (meth) acrylic acid ester copolymer, styrene-
Isoprene copolymer, styrene-butadiene copolymer,
Examples thereof include acrylonitrile-butadiene copolymer. These thermoplastic resins are used alone or in combination.

The glass transition temperature of the thermoplastic resin is in the range of -35 ° C to 70 ° C, more preferably -10 ° C to 60 ° C. If the glass transition temperature of the thermoplastic resin is lower than -35 ° C, the thermoplastic resin has tackiness even at room temperature, resulting in poor blocking resistance. 70
When the temperature exceeds ℃, when it is applied to the substrate as a heat-sensitive adhesive,
There is a problem that the surface strength of the surface coated with the heat-sensitive adhesive becomes weak and the printability becomes poor when used as a label.

The type of solid plasticizer used in the heat-sensitive adhesive of the present invention includes dihexyl phthalate (melting point 65.
℃), dicyclohexyl phthalate (melting point 63-65
C.), dihydroabietyl phthalate (melting point 65 ° C.), dimethyl isophthalate (melting point 66 to 67 ° C.), N-cyclohexyl-p-toluenesulfonamide (melting point 86).
° C), sucrose benzoate (melting point 98 ° C), ethylene glycol dibenzoate (melting point 70 ° C), trimethylolethane tribenzoate (melting point 73 ° C), pentaerythritol tetrabenzoate (melting point 95 ° C), sucrose octaacetate. (Melting point 89
C.), tricyclohexyl citrate (melting point 57.degree. C.) and the like having a melting point of 50 to 100.degree.
If the melting point is less than 50 ° C, the blocking resistance is poor and 1
If it exceeds 00 ° C, there is a problem that it is difficult to activate by heating. The solid plasticizer melts at a temperature equal to or higher than the melting point when activated by heating to plasticize the thermoplastic resin, and thus provides tackiness as a heat-sensitive adhesive, but the duration of tackiness varies depending on the solid plasticizer. It is preferable to use dicyclohexyl phthalate when the stickiness is prolonged. The solid plasticizers may be used alone or in combination of two or more.

The average particle size of the solid plasticizer is 2 to 10
μm is preferred. Incidentally, if the average particle size is less than 2 μm, the blocking resistance is poor, and if it exceeds 10 μm, it takes time for the solid plasticizer to melt when it is activated by heating and used as a label, and the tackiness as a heat-sensitive adhesive hardly appears. There is a problem.

As a method of making the solid plasticizer have the above-mentioned average particle diameter, the above solid plasticizer, the dispersant and water are mixed and appropriately pulverized by a ball mill, a sand mill or the like. As the dispersant, for example, methyl cellulose, carboxymethyl cellulose, polyvinyl alcohol, acrylic acid derivatives, sulfonic acid derivatives, maleic anhydride derivatives, various water-soluble polymers such as gelatin, anionic surfactants, nonionic surfactants, etc. Various surfactants can be used. The mixing ratio of solid plasticizer and dispersant is solid plasticizer 1
A dispersant of 0.5 to 10 solid parts by weight is preferred with respect to 00 solid parts by weight. It is more preferably 1 to 5 parts by weight solids.
When the amount of the dispersant is less than 0.5 parts by weight, the solid plasticizer is insufficiently dispersed in water, and the finely divided primary particles cause reaggregation. Further, if it exceeds 10 parts by weight, there is a problem that the adhesive performance is deteriorated.

As the heat-sensitive adhesive, in addition to a thermoplastic resin and a solid plasticizer, a rosin-based tackifier, a phenol resin-based tackifier, a terpene resin-based tackifier, a xylene-based tackifier, and a petroleum resin-based tackifier. A tackifier such as a tackifier may be included to adjust the adhesive function.

The mixing ratio of the thermoplastic resin and the solid plasticizer in the heat-sensitive adhesive is 50 to 400 solid parts by weight based on 100 solid parts by weight of the thermoplastic resin. Incidentally, when the solid plasticizer is less than 50 solid parts by weight, there is a problem that the adhesiveness as a heat-sensitive adhesive is less likely to appear and the adhesive function is poor. When the solid plasticizer is used in an amount of more than 400 solid parts by weight, there is a problem that the duration of tackiness becomes short as a heat-sensitive adhesive. When a tackifier is added, the tackifier is added to 10 parts by weight with respect to 100 parts by weight of the thermoplastic resin.
It is preferable to blend up to 150 solid parts by weight. If the tackifier is less than 10 parts by weight, the effect of enhancing the adhesive function is poor, and if it exceeds 150 parts by weight, the blocking resistance is poor.

The coating amount of the heat-sensitive adhesive is preferably 5 to 50 g / m ^{2 in} dry weight. More preferably 10
Is about 30 g / m ² . Incidentally, when the coating amount is less than 5 g / m ² , there is a problem that when used as a label, a sufficient adhesive function cannot be obtained and the label cannot be used. On the other hand, if it exceeds 50 g / m ² , it takes time to heat and activate the heat-sensitive adhesive, and the adhesive function is saturated, resulting in poor economy.

The method for applying the heat-sensitive adhesive on the substrate is brush coating, spray coating, screen printing, gravure printing, offset printing, letterpress printing, Mayer bar coater, kiss roll coater, lip coater, direct roll coater. , An offset roll coater, a gravure roll coater, a reverse roll coater, a rod coater, a blade coater, an air knife coater, and the like. Drying can be carried out by a conventional method combined with the above-mentioned device for coating.

The drying must be carried out at a temperature lower than the melting point of the solid plasticizer used. This is because if the solid plasticizer is dried at a temperature higher than the melting point of the solid plasticizer, the solid plasticizer melts during the drying and the heat-sensitive adhesive layer becomes tacky. For the above reasons, the drying temperature is generally 5
It is preferably 0 ° C. or lower.

Examples of the material of the base material to which the heat-sensitive adhesive of the present invention is applied include papers, synthetic papers, films, metal foils, non-woven fabrics, woven fabrics, and sheets in which these are appropriately laminated. Needless to say, various layers such as a heat-sensitive recording layer, a pressure-sensitive recording layer, a thermal transfer image-receiving layer, an inkjet recording layer, and a pigment coating layer may be provided on the surface of these base materials. On the other hand, the surface to which the heat-sensitive adhesive is applied may be provided with a barrier layer to reinforce the strength or prevent the heat-sensitive adhesive from penetrating into the substrate and deteriorating the adhesive function. When used as a label, printability and the like are required. In particular, when used as a label to be attached to a glass bottle containing a liquid such as soft drink, alcoholic beverage, and chemical bottle, it is preferable to use a substrate having excellent water resistance. Further, an ink or the like may be added to the heat-sensitive adhesive layer to color the heat-sensitive adhesive, or a heat-expandable microsphere may be contained to adjust the adhesive function.

[0028]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.
In the examples, "parts by weight" means "parts by weight of solid" unless otherwise specified.

[Preparation of Solid Plasticizer] Preparation of Solid Plasticizer (1) 100 parts by weight of dicyclohexyl phthalate (melting point: 64.7 ° C., manufactured by Osaka Organic Chemical Industry Co., Ltd.), a nonionic surfactant (trade name) as a dispersant. (Neugen EA-120 manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) 2.4 parts by weight and water were uniformly mixed to a concentration of 62%, and the mixture was pulverized with a ball mill until the average particle size became 5.5 μm.

Preparation of Solid Plasticizer (2) 100 parts by weight of N-cyclohexyl-p-toluenesulfonamide (melting point: 86 ° C., manufactured by Lancaster), a nonionic surfactant (trade name: Neugen E) as a dispersant.
(A-120 manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) 2.4 parts by weight and water were uniformly mixed to a concentration of 62%, and the mixture was pulverized using a ball mill until the average particle size became 1.5 μm.

Example 1 [Preparation of heat-sensitive adhesive] Ethylene-vinyl chloride copolymer having a glass transition temperature of 20 ° C. as a thermoplastic resin (trade name: Sumielite 1210, Sumitomo Chemical Co., Ltd.)
A thermosensitive adhesive having a solid content concentration of 50% was prepared, which was composed of 250 parts by weight of the solid plasticizer (1) and 0.2 parts by weight of carboxymethyl cellulose as a thickener per 100 parts by weight. The Brookfield viscosity of this heat-sensitive adhesive at 6 ° C. at 25 ° C. was 3200 cps. [Preparation of heat-sensitive adhesive sheet] Double-sided art paper (trade name: S gold <73>) with a weight of 84.9 g / m ² , Manufactured by Shin-Oji Paper Co., Ltd.) was coated on one surface with a reverse roll coater so that the dry weight was 21 g / m ^2, and dried to obtain a heat-sensitive adhesive sheet. .

Example 2 A heat-sensitive adhesive sheet was obtained in the same manner as in Example 1 except that 0.5 part by weight of carboxymethyl cellulose was added in the preparation of the heat-sensitive adhesive of Example 1. The Brookfield viscosity of the heat-sensitive adhesive at 25 ° C at 6 rpm was 11,000 cps.

Example 3 A heat-sensitive adhesive sheet was obtained in the same manner as in Example 1 except that 20 parts by weight of magnesium carbonate was added as a thickening agent in the preparation of the heat-sensitive adhesive of Example 1. The Brookfield viscosity of the heat-sensitive adhesive at 25 ° C at 6 rpm was 4800 cps.

Example 4 A heat-sensitive adhesive sheet was obtained in the same manner as in Example 1 except that 2 parts by weight of polyether polycarboxylic acid was added as a thickening agent in the preparation of the heat-sensitive adhesive of Example 1. . The Brookfield viscosity of the heat-sensitive adhesive at 25 ° C at 6 rpm was 2200 cps.

Example 5 The procedure of preparing the heat-sensitive adhesive of Example 1 was repeated except that 4 parts by weight of urethane-modified polyether was added as a thickener.
A heat-sensitive adhesive sheet was obtained in the same manner as in Example 1. In addition,
The Brookfield viscosity of the heat-sensitive adhesive at 25 ° C. at 6 rpm was 24000 cps.

Example 6 In the preparation of the heat-sensitive adhesive of Example 5, 50 parts by weight of a rosin-based tackifier (trade name: Super Ester E-710, manufactured by Arakawa Chemical Industry Co., Ltd.) was added to the heat-sensitive adhesive. Was added to obtain a heat-sensitive adhesive having a solid content concentration of 45% to obtain a heat-sensitive adhesive sheet in the same manner as in Example 1. In addition,
The Brookfield viscosity of the heat-sensitive adhesive at 25 ° C. and 6 rpm was 3700 cps.

Example 7 [Preparation of heat-sensitive adhesive] 150 parts by weight of solid plasticizer (2) per 100 parts by weight of SBR having a glass transition temperature of 9 ° C. (trade name: P4626, Sumitomo Dow Co., Ltd.) as a thermoplastic resin Part and carboxymethyl cellulose 0.2 as thickener
A thermosensitive adhesive having a solid content concentration of 45% by weight was prepared. The Brookfield viscosity of this heat-sensitive adhesive at 25 ° C. at 6 rpm was 6100 cps. [Preparation of heat-sensitive adhesive sheet] A heat-sensitive adhesive sheet was obtained in the same manner as in Example 1 except that the above heat-sensitive adhesive was used.

Example 8 [Preparation of heat-sensitive adhesive] A heat-sensitive adhesive was obtained in the same manner as in Example 1 except that 5 parts by weight of polyether polycarboxylic acid was added as a thickener. It was The Brookfield viscosity of the heat-sensitive adhesive at 25 ° C. at 6 rpm was 33000 cps. [Preparation of heat-sensitive adhesive sheet]
℃ while heating the both sides art paper basis weight 84.9 g / m ^2: using a reverse roll coater to one side (trade name S gold both <73>), so that the dry weight 21g / m ² After coating and drying, a heat-sensitive adhesive sheet was obtained. 50 ° C
Brookfield viscosity at 6 rpm is 140
It was 00 cps.

Example 9 [Preparation of heat-sensitive adhesive sheet] The same as Example 1 except that the heat-sensitive adhesive prepared in Example 8 was diluted and applied so that the solid content concentration was 45%. To obtain a heat-sensitive adhesive sheet. In addition, when diluted to 45%,
Brookfield viscosity at rpm is 11000 cps
Met.

COMPARATIVE EXAMPLE 1 In Example 1, carboxymethyl cellulose was added to 0.1%.
A heat-sensitive adhesive was prepared in the same manner as in Example 1 except that 1 part by weight was added. The Brookfield viscosity of this heat-sensitive adhesive at 6 ° C. at 25 ° C. is 1300 cps.
Met.

Comparative Example 2 A heat-sensitive adhesive was prepared in the same manner as in Example 1 except that carboxymethyl cellulose was not added. 6 rp of this heat-sensitive adhesive at 25 ° C
Brookfield viscosity at m was 60 cps.

Comparative Example 3 A heat-sensitive adhesive was prepared in the same manner as in Example 7, except that carboxymethyl cellulose was not added. 6 rp of this heat-sensitive adhesive at 25 ° C
Brookfield viscosity at m was 90 cps.

Comparative Example 4 A heat-sensitive adhesive was prepared in the same manner as in Example 1 except that 1 part by weight of carboxymethyl cellulose was added. 6r of this heat-sensitive adhesive at 25 ° C
The Brookfield viscosity in pm was 38000 cps. This heat-sensitive adhesive was heated to 50 ° C. and applied in the same manner as in Example 8. 6 rpm at 50 ° C
Brookfield viscosity at 2000 was 20,000 cps.

Comparative Example 5 A heat-sensitive adhesive was prepared in the same manner as in Example 1 except that 3 parts by weight of carboxymethyl cellulose was added. 6r of this heat-sensitive adhesive at 25 ° C
Brookfield viscosity at pm is 100,000 cps
It was above (not measurable). This heat-sensitive adhesive was heated to 50 ° C. and applied in the same manner as in Example 8. Note that 50
Brookfield viscosity at 6 rpm at 6 ° C is 92
000 cps.

"Evaluation" The standing stability of the heat-sensitive adhesive prepared in each Example and Comparative Example, the production suitability of the heat-sensitive adhesive sheet,
The adhesive function and blocking resistance of the obtained heat-sensitive adhesive sheet were evaluated, and the results are shown in Table 1.

[Stability at rest] The height of the heat-sensitive adhesive is 50
The mixture was placed in a cm transparent container and allowed to stand at 25 ° C. for 24 hours, and the sedimentation state of the pressure-sensitive adhesive component was visually evaluated. ⊚: Sedimentation of the adhesive component is hardly seen. ◯: Sedimentation of the adhesive component is observed, but there is no problem in practical use. Δ: The pressure-sensitive adhesive component settles, which is a problem in practical use. X: The pressure-sensitive adhesive component settles badly and cannot be used.

[Productivity] When the heat-sensitive adhesive was applied to the double-sided art paper by the method described above, the controllability of the application amount and the uniformity of the application surface were evaluated. ⊚: The coating amount is easy to control, and a uniform coating surface can be easily obtained. ◯: It is difficult to control the coating amount or it is difficult to obtain a uniform coating surface. X: It is difficult to control the coating amount and a uniform coating surface cannot be obtained.

[Adhesive Function] A heat-sensitive adhesive sheet is placed at 120 ° C.
It was heat-activated for 15 seconds in an oven heated to 3 minutes, and after heating for 3 minutes, it was attached to a glass plate. After 2 hours, measure the adhesive strength at an angle of 180 ° C. and a speed of 0.3 m / min,
It was judged according to the following criteria. ⊚: The adhesive force is 800 g / 25 mm or more, and the adhesive force is excellent. ◯: Adhesive strength is 400 g / 25 mm or more, and there is no practical problem. X: Adhesive strength is less than 400 g / 25 mm, and it is practically problematic because it can be easily peeled by hand.

[Blocking Resistance] The heat-sensitive adhesive sheet was wound and treated at 45 ° C. for 7 days to evaluate the occurrence of blocking. ◯: Very good with almost no blocking. Δ: A little blocking occurs, but there is no practical problem. X: Blocking occurs, and there is a practical problem.

[Comprehensive Evaluation] From the results of evaluating the stability of standing with respect to the heat-sensitive adhesive, the production suitability of the heat-sensitive adhesive sheet, and the adhesive function and blocking resistance of the heat-sensitive adhesive sheet, the one having excellent quality is A comprehensive evaluation was carried out by assigning ○ as a practically no problem, △ as a practically problematic one, and × as a practically problematic one. Table 1 shows the results.

[0051]

[Table 1]

As shown in Table 1, the Brookfield viscosity at 25 ° C. is 2000 to 100000 cps (6
All of the heat-sensitive adhesives satisfying rpm) have excellent static stability. Further, as shown in Examples 1 to 7, the Brookfield viscosity at 25 ° C. is 2000 to 30000.
cps (6 rpm) is applied using a heat-sensitive adhesive, and the Brookfield viscosity at 25 ° C. of the heat-sensitive adhesive as in Example 8 is 15,000 at 6 rpm.
Using 100,000 cps, the melting point of the solid plasticizer is below, and the Brookfield viscosity is 6 rpm.
At a temperature of 3000-15000 cps,
Both the method for producing the heat-sensitive adhesive sheet which is applied in a state satisfying the viscosity range are excellent in production suitability, and the obtained heat-sensitive adhesive sheet is excellent in both the adhesive function and the blocking resistance.

[0053]

INDUSTRIAL APPLICABILITY As described above, according to the present invention, a heat-sensitive pressure-sensitive adhesive preservative book capable of stably producing a heat-sensitive pressure-sensitive adhesive sheet excellent in static stability, adhesive function and blocking resistance. Method and manufacturing method.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical indication C09J 201/00 JAU C09J 201/00 JAU

Claims (6)

[Claims] 1. When storing a heat-sensitive adhesive containing a thermoplastic resin and a solid plasticizer as main components, 25 of the heat-sensitive adhesive is used.
Brookfield viscosity at ℃ 2000 ~ 100
A method for storing a heat-sensitive adhesive, characterized in that the pressure-sensitive adhesive is set to 000 cps (6 rpm). 2. The method for storing a heat-sensitive adhesive according to claim 1, wherein the solid plasticizer has an average particle diameter of 2 to 10 μm. 3. A method for producing a heat-sensitive adhesive sheet, which comprises applying a heat-sensitive adhesive containing a thermoplastic resin and a solid plasticizer as main components to one surface of a base material, and then drying it.
Brookfield viscosity at 2000-3000
A method for producing a heat-sensitive adhesive sheet, which is 0 cps (6 rpm). 4. The Brookfield viscosity of the heat-sensitive adhesive at 25 ° C. is 3000 to 15000 cps (6 rpm).
The method for producing a heat-sensitive adhesive sheet according to claim 3, wherein 5. A method for producing a heat-sensitive adhesive sheet, which comprises applying a heat-sensitive adhesive containing a thermoplastic resin and a solid plasticizer as main components to one surface of a base material, and drying it.
Brookfield viscosity at 15,000-100
000 cps (6 rpm) was used, and the Brookfield viscosity was 30 in the range below the melting point of the solid plasticizer.
A method for producing a heat-sensitive adhesive sheet, which comprises heating to a temperature of from 0 to 15000 cps (6 rpm) and applying. 6. The method for producing a heat-sensitive adhesive sheet according to claim 5, wherein heating is performed in a region of 50 ° C. or lower.