JPH0841432A - Heat sensitive adhesive sheet - Google Patents

Abstract

(57) [Summary] [Object] The present invention solves the problems of storage stability of heat-sensitive adhesive sheets, especially blocking properties, and further provides a heat-sensitive adhesive sheet with less wrinkling during sticking. The purpose is to [Structure] A display layer (4) is provided on the front surface of a substrate (1) and a heat-sensitive adhesive layer (2) is provided on the back surface, and an anti-blocking layer having a fine pattern is formed on the heat-sensitive adhesive layer (2). A heat-sensitive adhesive sheet in which (3) is sequentially laminated. [Effect] By providing the anti-blocking layer consisting of a fine pattern, the storage stability of the sheet, especially the blocking property was improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adhesive tape to be adhered to an adherend such as a box or a plastic container and a heat-sensitive adhesive sheet for a display label, which can improve work efficiency and quality during use. And a heat-sensitive adhesive sheet.

[0002]

2. Description of the Related Art Generally, a heat-sensitive adhesive sheet has a surface such as a paper or a plastic film on which a marking such as a picture, a letter or a symbol is provided by printing or the like, and the back surface thereof has a heat-sensitive adhesive composition. There is provided a heat-sensitive adhesive layer coated with a material. This heat-sensitive adhesive composition is already known, for example, "Adhesion Handbook", 12th Edition, 131st.
Page (published by Kobunshi Publishing Co., Ltd. 1955).
That is, the basic composition is a polymeric material, a tackifier,
An adhesive (adhesive) composed of a solid plasticizer, which is not tacky at room temperature, but becomes sticky when heated and continues for a considerable period after cooling. The dry coating of this adhesive is not tacky and therefore requires no release paper. According to these descriptions and other known documents, a heat-sensitive adhesive sheet can be obtained on a trial basis, but there is a problem in storage stability in practical use, and particularly non-adhesiveness is maintained under non-heating conditions. It has been found that the blocking properties are not satisfied. This characteristic is related to the production, storage, transportation, processing, printing, use, etc. of the heat-sensitive adhesive sheet, and the sheets stick together when unrolling or peeling due to environmental temperature and pressure. , It is recognized by making a slight clicking noise when peeling.
Particularly, in practical use, it is inevitable to be placed under a high temperature and pressure, so that a wide allowable range is desirable. Also,
At the time of sticking this adhesive sheet, when the adherend such as a bottle has a curved surface, a sticking machine such as an automatic labeler is used,
The label was easily wrinkled, which was a factor of lowering the yield.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and solves the problems of storage stability of heat-sensitive adhesive sheets, in particular, blocking characteristics, and further prevents wrinkles during application. An object of the present invention is to provide a heat-sensitive adhesive sheet with less occurrence of

[0004]

In order to achieve the above object, the present invention provides a heat-sensitive adhesive layer containing a polymeric material, a solid plasticizer and a tackifier as a basic component on one surface of a substrate. The heat-sensitive adhesive sheet is characterized in that a blocking prevention layer having a net-like, dot-like, or stripe-like fine pattern is further provided on this layer.

Further, the anti-blocking layer composed of the fine pattern is characterized by having an area ratio of 20 to 70%.

The present invention will be described in detail with reference to the drawings. FIG.
, A base material (1) provided with a display layer (4) such as a pattern on one surface, and a heat-sensitive adhesive layer (2) on the other surface of the base material.
And a blocking prevention layer (3) having a fine pattern.

As the substrate (1), paper, plastic film, resin synthetic paper or the like can be used and can be selected appropriately. The base material (1) is provided with a display layer (4) with a picture, a character, a symbol or the like on one surface by printing or the like, and an anchor coat layer or a vapor deposition layer for the display layer may be provided. The display layer is not limited to the above, and the display layer may not be provided and can be appropriately selected.

The heat-sensitive adhesive layer (2) is composed of a polymer material, a tackifier and a solid plasticizer. The polymer material, which is the basic component of the heat-sensitive adhesive composition that constitutes the component, is a component that imparts adhesive force, and examples thereof include polyvinyl acetate, copolyethylene-vinyl acetate, polyacrylate ester-based, polyvinyl chloride-based, natural rubber, Synthetic rubber, copolyvinyl acetate-acrylic acid ester, polyester-based and polyurethane-based polymer compounds can be used.

The solid plasticizer, which is the basic component of the heat-sensitive adhesive composition, is solid at room temperature and melts when heated above its melting point to swell and dissolve the polymer material and tackifier. Then, it develops stickiness and adhesiveness. Further, since it does not easily crystallize after being once melted, the adhesive holding time after heat activation can be extended. For example, diphenyl phthalate, dihexyl phthalate, dicyclohexyl phthalate, dihydroabietyl phthalate, dimethyl isophthalate, benzoic acid scroll, ethylene glycol dibenzoate, trimethylolethane tribenzoate, tribenzoic acid glyceride, tetrabenzoic acid penta Eriette,
Octaacetic acid scroll, tricyclohexyl citrate N
An organic compound that is solid at room temperature such as cyclohexyl-P-toluenesulfonamide is used.

Further, the tackifier, which is a basic component of the heat-sensitive adhesive composition, is a component for enhancing the adhesiveness when activated by heating, and for example, a rosin derivative, a terpene resin system, a petroleum resin system. Resins such as phenol resin type and xylene resin type are used.

Further, the anti-blocking layer (3) provided on the heat-sensitive adhesive layer (2) is formed by forming a fine pattern such as a mesh, a dot or a stripe, and its material is acrylic resin or styrene resin. , Styrene copolymer,
Cellulose derivative, polyester resin, butyral resin, polyamide resin, rosin ester resin, polyurethane resin, methacrylic resin, polyvinyl acetate resin, polyvinyl chloride, vinyl chloride / vinyl acetate copolymer, ethylene / vinyl acetate copolymer, chlorinated rubber, One or more of chlorinated polyolefin resin and petroleum resin are used.

Further, the antiblocking layer (3) composed of a fine pattern has a good result in an area ratio of 20 to 70%. When the lower limit of the area ratio is 20% or less, the blocking prevention layer does not play a role and the blocking property is deteriorated. The upper limit of the area ratio is 70%
This is because the adhesive performance of the pressure-sensitive adhesive layer is inferior in the above case, and by keeping the area ratio within the range of 20 to 70%, the blocking property can be improved without losing the adhesive performance.

[0013]

According to the heat-sensitive adhesive sheet of the present invention, in the storage stability, due to the anti-blocking layer composed of a fine pattern, the anti-adhesiveness under non-heating conditions is good, and the anti-blocking property is good. Since the layer portion does not have tackiness, strain is easily absorbed at the time of sticking, which makes it possible to reduce the occurrence of wrinkles.

[0014]

EXAMPLES Specific examples of the present invention will be described.

Example 1 First, the heat-sensitive adhesive layer (2)
Is an aqueous emulsion of acrylic acid ester copolymer as a polymer material, an aqueous emulsion of rosin ester as a tackifier (softening point 120 ° C.), and an aqueous dispersion of dicyclohexyl phthalate (melting point 64 as a solid plasticizer. ℃), a solid content concentration of 50
% Using a lower alcohol solvent,
A heat-sensitive adhesive composition having an aqueous resin dispersion (emulsion) was prepared. This heat-sensitive adhesive composition is applied to a thickness of 50 μm.
Using a polyester film of m as a base material, a dry coating amount of 20 g / m ² was coated on one surface of the polyester film, and the coating was dried at a temperature of 45 ° C. for 2 minutes to provide a heat-sensitive adhesive layer. Next, an aqueous emulsion of acrylic polymer (softening point 100
(C)) is mixed with water to a solid content concentration of 50% to prepare a coating liquid that presents an aqueous resin dispersion (emulsion), and the area ratio is changed to a stripe shape to change the thickness. To a thickness of 2 μm to obtain a heat-sensitive adhesive sheet.

<Test> Next, a confirmation test was conducted to check the characteristics of the heat-sensitive adhesive sheet obtained in Example 1. The confirmation test method for this heat-sensitive adhesive sheet is shown below. A test piece of a heat-sensitive adhesive sheet having a width of 15 mm in which the area ratio of the adhesive blocking prevention layer was divided into 0 to 100% was measured at a temperature of 12
By heating at 0 ° C. for 20 seconds, the solid plasticizer in the heat-sensitive adhesive composition is heat-activated to develop adhesiveness, and the adhesiveness is measured after adhering to a glass plate for 24 hours. According to JIS-Z-0237. The measured value is 500
The product suitability value is g / 25 mm or more. Blocking characteristics Two heat-sensitive adhesive sheets each having an area ratio of the anti-blocking layer divided into 0 to 100% are laminated so that the front surface and the back surface face each other, and the pressure-sensitive adhesive sheet is placed in an atmosphere at a pressure of 1 Kg / cm ² and a temperature of 50 ° C. Let stand for an hour and check for blocking. Table 1 shows the above results.

[0017]

[Table 1]

[0018]

EFFECTS OF THE INVENTION The heat-sensitive adhesive sheet of the present invention is a sheet having storage stability of the adhesive sheet, particularly excellent blocking property, by providing an anti-blocking layer having a fine pattern on the heat-sensitive adhesive layer. . Further, since this blocking prevention layer portion has no tackiness, it is easy to absorb strain when it is attached to an adherend, and the occurrence rate of wrinkles can be reduced.

[Brief description of drawings]

FIG. 1 is a side sectional view showing an example of a laminated constitution of a heat-sensitive adhesive sheet of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Substrate 2 ... Thermosensitive adhesive layer 3 ... Blocking prevention layer 4 ... Display layer

Front page continuation (72) Inventor Nobuaki Horii 1-5-1 Taito, Taito-ku, Tokyo Toppan Printing Co., Ltd.

Claims (2)

[Claims] 1. A polymer material, a solid plasticizer, and
A heat-sensitive pressure-sensitive adhesive sheet having a heat-sensitive adhesive layer containing a tackifier as a basic component, wherein a blocking prevention layer having a fine pattern is provided on the pressure-sensitive adhesive layer. 2. The heat-sensitive adhesive sheet according to claim 1, wherein the anti-blocking layer comprising the fine pattern has an area ratio of 20 to 70%.