JPH08209079A - Tacky sheet - Google Patents

Abstract

PURPOSE: To obtain a sheet capable of using for decorating or displaying and excellent in weather resistance and cutting property by cutting machine, following property to adherend and executability. CONSTITUTION: This tacky sheet is laminated in the order of a release sheet/a pressure-sensitive adhesive/a substrate and the substrate is composed of a flexible synthetic resin film and an acrylic tacky agent containing a plasticizer and the adhesive having 50-100μm/30μm tensile shear displacing amount is used as the pressure-sensitive adhesive.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention can be used outdoors or indoors.
The present invention relates to a pressure-sensitive adhesive sheet which is mainly used for adhering to various objects for decoration or for displaying markings and the like. In the present invention, the film, tape, and sheet are collectively referred to simply as "sheet" without intentionally distinguishing them.

[0002]

2. Description of the Related Art Conventionally, a pressure-sensitive adhesive sheet used for decoration or display has a structure in which a release sheet / pressure-sensitive adhesive / base material are laminated in this order. The mainstream is acrylic type, which is more excellent in weather resistance than rubber type, and the base material is made of a soft synthetic resin film excellent in followability to an adherend. Is common.

For decoration and display, cutout patterns such as cut letters and cutouts are prepared from the adhesive sheet and attached to an adherend. The cutout pattern is controlled by a computer. Cutting machine used.

The cutter of this cutting machine generally moves quickly, and during cutting, a phenomenon of so-called curling occurs at the interface between the release sheet and the pressure-sensitive adhesive. Therefore, in order to solve this turning-over phenomenon and improve the cutting property with a cutting machine, it is disclosed in Japanese Patent Laid-Open No. 2-8
As described in Japanese Patent No. 4476, a method for increasing the adhesive force between a pressure sensitive adhesive and a release sheet, so-called release force, has been developed.

On the other hand, a soft synthetic resin film is usually formed by adding a plasticizer to a synthetic resin in order to impart excellent flexibility. However, the plasticizer in the base film has a strong tendency to transfer to the pressure-sensitive adhesive with the passage of time of the pressure-sensitive adhesive sheet, and the transfer accelerates curing of the base material and aging of the adhesive, resulting in a decrease in adhesive strength. There was a problem.

Therefore, in order to solve the migration phenomenon of the plasticizer in the substrate film and prevent the aging of the pressure-sensitive adhesive while maintaining the flexibility of the substrate, it is described in JP-A-2-18486. As described above, a method of adding a plasticizer into a pressure sensitive adhesive has been developed. Since the pressure sensitive adhesive is also softened by the addition of the plasticizer, there is an accompanying effect that it not only prevents the transfer of the plasticizer from the base material but also contributes to the improvement of the followability to the adherend.

[0007]

However, among the techniques described in the above publications, in the case of the technique for improving the cuttability disclosed in Japanese Patent Laid-Open No. 2-84476, an application is required for sticking to an adherend. When the method of transferring once to the sheet is adopted, there is a problem that the transferring becomes difficult and the workability is poor.

In the case of the technique for preventing plasticizer migration described in JP-A-2-18486, the amount of plasticizer added to the pressure sensitive adhesive is such that the migration of plasticizer from the base material is exclusively prevented. , The number of parts to be added has been calculated with an emphasis on maintaining and improving the adhesive strength of pressure-sensitive adhesives.

However, if the number of parts to be added is set only from such a viewpoint, the plasticizer may migrate to the base material and the physical properties of the base material may be changed if the addition amount is excessive. In addition, the pressure-sensitive adhesive becomes too soft and becomes sticky in the summer, resulting in new problems such as reduced handling workability and reduced cutting performance due to pressure-sensitive adhesive sticking to the machine when cutting with a cutting machine. Was done.

The present invention secures the cuttability by a cutting machine without sacrificing the workability of the pressure-sensitive adhesive sheet used for decoration and display, and also allows the plasticizer to migrate from the soft synthetic resin film. In order to prevent it, it is premised that a pressure sensitive adhesive with a plasticizer added is used, but an object thereof is to provide a pressure-sensitive adhesive sheet that does not cause any new problems due to the addition of the plasticizer. And

[0011]

The pressure-sensitive adhesive sheet of the present invention comprises:
Assuming that a soft synthetic resin film is used as a base material and an acrylic pressure-sensitive adhesive containing a plasticizer is used as a pressure-sensitive adhesive, the tensile shear displacement of the pressure-sensitive adhesive is 50 to 100.
The main point is to use a material having a thickness of μm / 30 μm.

Examples of the soft synthetic resin film as a base material of the pressure-sensitive adhesive sheet of the present invention include polyvinyl chloride type, polyvinylidene chloride type, polyvinyl acetate type, polyvinyl butyral type, polyacrylic acid ester type and the like. In addition,
The term "system" as used herein includes homopolymers, various copolymers, blends of both, blends with other resins, and the like in its category.

Plasticizers are usually used in these films.
It is contained in an amount of 0 to 60% by weight, and if necessary, a colorant, an ultraviolet absorber, a stabilizer and other additives are used.

In the present invention, an acrylic pressure-sensitive adhesive containing a plasticizer is used as a constituent of the pressure-sensitive adhesive. As the acrylic pressure-sensitive adhesive that is the main component, known ones used for pressure-sensitive adhesive sheets are adopted, but usually (meth) acrylic acid alkyl ester is the main component, and if necessary, other modifying monomer components are added in appropriate amounts. Introduced to design quality of pressure sensitive adhesive. For example, it is possible to cite a copolymer of (meth) acrylic acid alkyl ester as a main component, which is copolymerized with a vinyl monomer or the like.

Examples of the (meth) acrylic acid alkyl ester include methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate,
2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, isononyl (meth) acrylate, octyl (meth) acrylate, decyl (meth)
Alkyl (meth) acrylates having 11 or less carbon atoms in the alkyl group such as acrylate can be mentioned.

Further, as the vinyl monomer, (meth)
Carboxylic acid-containing monomers such as acrylic acid, crotonic acid, maleic acid, fumaric acid, itaconic acid, vinyl acetate, styrene, N-vinylpyrrolidone, acrylonitrile, 2-hydroxyethyl (meth) acrylate, 2- (meth) acrylic acid 2- Examples thereof include hydroxypropyl, tetrafurfuryl acrylate, polyethylene glycol acrylate and the like.

Examples of the method for polymerizing the acrylic pressure-sensitive adhesive include a radical polymerization method utilizing solution polymerization (including constant temperature solution polymerization), bulk polymerization, emulsion polymerization and the like. Examples of the polymerization initiator at this time include benzoyl peroxide and azobisisobutyronitrile.

In the present invention, one of the important requirements is to use the acrylic adhesive containing a plasticizer. The plasticizer is roughly classified into a monomer system and a polymer system. In the former, for example, dioctyl phthalate (DO) is used.
P), phthalic acid diesters such as dibutyl phthalate (DBP), phosphoric acid triesters such as tricresyl phosphate (TCP), and the like. The latter is typically a low molecular weight saturated linear polyester system. As.

The purpose of using these plasticizers is to prevent migration of the plasticizer from the soft synthetic resin film, but the amount of tensile shear displacement of the adhesive, which will be described later, falls within a specific range. Another aim is to exert the function as a regulator to limit the above.

These plasticizers may be used alone or in combination of two or more, with the most suitable one being selected depending on the components of the acrylic pressure-sensitive adhesive. The amount of addition to the acrylic pressure-sensitive adhesive is preferably 1 to 20 parts by weight, and more preferably 2 to 15 parts by weight, based on 100 parts by weight of the acrylic pressure-sensitive adhesive, according to the invention of claim 2. preferable. If it is less than 1 part by weight, the prevention of migration of the plasticizer is insufficient, and if it exceeds 20 parts by weight, softening and stickiness of the pressure-sensitive adhesive are increased and the workability and the cuttability are deteriorated, which is not preferable. The plasticizer in the pressure-sensitive adhesive and the plasticizer in the substrate film may be the same or different.

The pressure-sensitive adhesive thus prepared must have a tensile shear displacement within the range of 50 to 100 μm per 30 μm of the pressure-sensitive adhesive layer. , Preferably in the range of 60 to 80 μm. If the amount of tensile shear displacement is less than 50 μm, the pressure-sensitive adhesive lacks flexibility and follows the adherend poorly. There is a risk that the cutting performance will be poor.

The method of measuring the amount of tensile shear displacement of the present invention is carried out under the environmental conditions of temperature = 23 ° C. and relative humidity = 65%.
As shown in FIG. 1 (a), a flat plate type adherend 1 having a width of 5 mm is set on a mounting jig (not shown) of a tester, and a test piece 2 (width = 25 mm, length = 200 mm) of an adhesive sheet is set thereon. Affix. In addition, 3 is a base material and 4 is a pressure-sensitive adhesive layer.
In addition, at the time of the attachment, a mark 5 is preliminarily provided at the center of the surface of the base material 3 in the longitudinal direction, and the mark 5 is applied to the adherend 1.
Stick it so that it is located in the center of.

At this time, one end of the yarn is fixed to both ends of the test piece 2 in the longitudinal direction, and the other end is attached to the pulley 6,
Balance via 6 Next, as shown in FIG. 1 (b), a weight 7 of 500 g is attached to one of the threads, and the amount of displacement after 1 minute, that is, the deviation from the position where the tape is initially attached, is measured in μm units by a detection means (not shown). To do. Since this deviation depends on the thickness of the pressure-sensitive adhesive layer, the thickness of the pressure-sensitive adhesive layer is 3
The value converted per 0 μm is the tensile shear displacement amount. Further, the displacement of the base film should be negligible.

For the measurement, a commercially available measuring machine, for example, a Yamamoto type flat plate type cohesive force measuring machine manufactured by Asahi Seiko Co., Ltd. can be used to obtain a measured value in the unit of μm.

[0025]

The pressure-sensitive adhesive sheet of the present invention uses an acrylic pressure-sensitive adhesive containing a plasticizer as a pressure-sensitive adhesive, so that it has not only the original excellent weather resistance of an acrylic pressure-sensitive adhesive but also pressure-sensitive adhesive from a substrate. It is possible to prevent the transfer of the plasticizer to the adhesive. Therefore, it is possible to suppress changes in the physical properties of the base material and prevent a decrease in the adhesive strength of the pressure-sensitive adhesive.

Further, since the pressure-sensitive adhesive is sufficiently softened by the plasticizer, the pressure-sensitive adhesive itself can be easily deformed to facilitate the conformability to the adherend and to form a complicated surface. Even if the adhesive sheet is bent or bent and adhered to the adherend, the stress applied to the pressure-sensitive adhesive sheet can be absorbed and the occurrence of floating or peeling from the adherend can be prevented.

The tensile shear displacement of the pressure sensitive adhesive is 5
Since it is limited to the range of 0 to 100 μm / 30 μm, it is a pressure-sensitive adhesive that has a well-balanced adhesive force and tensile shear displacement amount, responds well to changes in the operating environment, and It has cutting ability. Therefore, in comparison with the case where the addition amount was calculated for the purpose of preventing plasticizer migration, the plasticizer migrates to the base material to change the physical properties of the base material, the handling workability deteriorates, and the cutting property is reduced. There is no side effect of decreasing

[0028]

EXAMPLES Examples of the present invention will be described in detail below.

[Example 1] (Polymerization of acrylic pressure-sensitive adhesive) 50 parts by weight of butyl acrylate and 50 parts by weight of 2-ethylhexyl acrylate were used as alkyl acrylate, and 8 parts by weight of acrylic acid and hydroxyethyl were used as vinyl monomers. Using 0.5 parts by weight of methacrylate, these were dissolved in ethyl acetate, azobisisobutyronitrile was added as a polymerization initiator to this, and boiling point polymerization (constant temperature solution polymerization method) was performed to obtain Mw = 700,000. , Mw / Mn = 3.1 was obtained.

(Addition of plasticizer and production of adhesive sheet)
A plasticizer (polyester, P-300, manufactured by ADEKA ARGUS CORPORATION) is added to the acrylic pressure-sensitive adhesive to make the acrylic pressure-sensitive adhesive 1
3 parts by weight of solid content was added to 00 parts by weight, and a curing agent (Coronate L-5 manufactured by Nippon Polyurethane Co., Ltd.) was added to 100 parts by weight of solid content of the acrylic adhesive containing a plasticizer.
5E) is added in an amount of 0.4 part by weight and stirred, and the obtained pressure-sensitive adhesive is applied onto a colored flexible polyvinyl chloride sheet so that the dry thickness becomes 30 μm, and a release paper is laminated on the upper surface thereof. Then, a pressure-sensitive adhesive sheet sample was prepared.

Example 2 A pressure-sensitive adhesive sheet sample was obtained in the same manner as in Example 1 except that the addition ratio of the plasticizer was 6 parts by weight in terms of solid content.

[Example 3] (Polymerization of acrylic pressure-sensitive adhesive) 100 parts by weight of butyl acrylate and 13 parts by weight of acrylic acid were used as alkyl acrylate, and 0.1 part by weight of hydroxyethyl methacrylate was used as a vinyl monomer. Polymerization was conducted in the same manner as in Example 1 except that it was used, and Mw = 600,000, M
An acrylic pressure-sensitive adhesive with w / Mn = 3.5 was obtained.

(Addition of plasticizer and production of adhesive sheet)
A plasticizer (polyester, W-2600, manufactured by Dainippon Ink and Chemicals, Inc.) is added to the acrylic adhesive 1
4 parts by weight of solid content was added to 00 parts by weight, and a curing agent (Coronate L-5 manufactured by Nippon Polyurethane Co., Ltd.) was added to 100 parts by weight of solid content of the acrylic adhesive containing a plasticizer.
0.8 parts by weight of 5E) was added and stirred, and a pressure-sensitive adhesive sheet sample was obtained in the same manner as in Example 1.

Example 4 As Example 1 except that a monomer plasticizer (DOP manufactured by Sekisui Chemical Co., Ltd.) was added as a plasticizer in an amount of 8 parts by weight in solid content to 100 parts by weight of the acrylic adhesive. Similarly, a sample of the adhesive sheet was obtained.

Comparative Example 1 A pressure-sensitive adhesive sheet sample was obtained in the same manner as in Example 1 except that no plasticizer was added to the acrylic pressure-sensitive adhesive.

Comparative Example 2 A pressure-sensitive adhesive sheet sample was obtained in the same manner as in Example 3 except that no plasticizer was added to the acrylic pressure-sensitive adhesive.

Comparative Example 3 Example 1 except that the addition ratio of the plasticizer to the acrylic adhesive was 25 parts by weight.
A pressure-sensitive adhesive sheet sample was obtained in the same manner as in.

With respect to the pressure-sensitive adhesive sheet samples obtained in each of the above-mentioned Examples and Comparative Examples, each test item of tensile shear displacement, conformability to adherend (curved surface workability), and cutting property by cutting machine was tested. evaluated. Table 1 shows the results. The test / evaluation methods are as follows.

Measurement of tensile shear displacement: As described above (tester; Asahi Seiko Co., Ltd., Yamamoto type flat plate cohesive force tester)

Follow-up test and evaluation: An iron plate composed of a folded plate having a shape as shown in FIG. 2 (a) (mountain height 10 mm, mountain interval 50 mm) was used as the adherend 7, and FIG. The sample 8 was suspended between the ridges by the procedure shown in (c), and then the sample 8 was stretched and pushed into the valleys to be adhered, followed by a blank and a heating condition of 60 ° C. for 1 week and 2 The state of floating and peeling of each sample 8 after each week was visually observed, and the following three-stage evaluation was performed. 3 = No floating or peeling is observed. 2 = Some floating is observed. 1 = Complete floating is observed.

Cutability test and evaluation: A cutting machine (CG-45 manufactured by Mimaki Co., Ltd.) was used to form 5 letters of "Mori, Beauty, Swim, Aya", which is a 10 mm square Gosic body.
A total of 10 characters were cut for each character, and scraps were removed (removal of unnecessary portions) after 24 hours, and evaluation was made based on the number of remaining characters.

[0042]

[Table 1]

As is clear from the results shown in Table 1, each of the examples has an appropriate amount of tensile shear displacement, and satisfactory results were obtained for each test item. Comparative Examples 1 and 2 in which no plasticizer was added to the agent
In the case of No. 3, the tensile shear displacement amount was less than the predetermined range, and the followability with time was poor. In addition, in the case of Comparative Example 3 in which the amount of the plasticizer added was too large, the amount of tensile shear displacement was too large, resulting in poor cuttability by a cutting machine,
It could not be used.

[0044]

EFFECT OF THE INVENTION Since the pressure-sensitive adhesive sheet of the present invention is constructed as described above, it is required for a pressure-sensitive adhesive sheet used for decoration or display, which can balance the adhesive force and the amount of tensile shear displacement. With regard to quality characteristics such as weather resistance, followability, cuttability, and construction workability, which are the quality characteristics, the effects can be maintained for a long period of time.

[Brief description of drawings]

FIG. 1 is an explanatory view showing a method for measuring a tensile shear displacement amount, which is one of the test items of an adhesive sheet, in which (a) is a side surface part showing a state in which a test piece is attached to a testing machine, 4] is a side view showing a state where tension is applied to the test piece.

FIG. 2 is an explanatory view showing a test / evaluation method of followability which is one of the test items of the pressure-sensitive adhesive sheet, (a) a side view of the adherend, and (b) a sample on the adherend. FIG. 3 is a side view showing a mounted state, and (C) is a side view showing a state in which the sample is pressed and attached to an adherend.

[Explanation of symbols]

 1, 7 Adherend 2 Test piece 3 Base material 4 Pressure-sensitive adhesive layer 5 Mark 6 Pulley 8 Sample

Claims (2)

[Claims] 1. A pressure-sensitive adhesive sheet comprising a release sheet, a pressure-sensitive adhesive, and a base material laminated in this order, wherein the base material is a soft synthetic resin film, and the pressure-sensitive adhesive is an acrylic pressure-sensitive adhesive containing a plasticizer. Moreover, the amount of tensile shear displacement is 50 to 10
A pressure-sensitive adhesive sheet, which is in the range of 0 μm / 30 μm. 2. The pressure sensitive adhesive is an acrylic pressure sensitive adhesive 10.
The pressure-sensitive adhesive sheet according to claim 1, which comprises 1 to 20 parts by weight of a plasticizer with respect to 0 parts by weight.