JPH11222581A - Adhesive tape - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an adhesive tape wherein force is scattered over the entire tape width when a large winding pressure is applied and wherein the adhesive is fixed in the depressed part to prevent weaving. SOLUTION: In an adhesive tape partially having a region A wherein an adhesive is arranged in the width direction on the surface of a tape base, a depressed part is formed on one or both sides of the base within the adhesive- coated region A. Preferably, the depth (a) of the depressed part is from 0.1 to 1.2 times as large as the thickness (b) of the adhesive layer. This allows the force to be scattered over the entire width of the tape when a large winding pressure is applied, and also strongly inhibits weaving since the adhesive is fixed at the depressed part. Therefore, shear in the rolled form is inhibited when the tension applied to the tape grows larger as the application rate grows faster or when the tape is under storage. Furthermore, even when the rolled-up length of the tape is long, an extremely stable product which allows little weaving, is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention comprises at least one pair of a non-adhesive portion and an adhesive portion provided by partially applying an adhesive in the width direction of the surface of a tape base material (hereinafter, referred to as "the adhesive"). Also referred to as "partial pressure-sensitive adhesive coating.") The main purpose of the pressure-sensitive adhesive tape is to stabilize the winding shape of the tape.

[0002]

2. Description of the Related Art In a conventional pressure-sensitive adhesive tape coated with a partial adhesive, since the total thickness of the entire adhesive tape is increased by the thickness of the adhesive layer in the adhesive portion compared to the non-adhesive portion, the tape is wound in a tape shape. When the winding pressure is applied, the force is concentrated on the portion where the adhesive is applied, and the winding is easily shifted. If the roll is misaligned, it cannot be set on the tape attachment jig. Also, the appearance was often bad.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide an adhesive tape which eliminates the above-mentioned drawbacks and is less likely to cause a tape displacement.

[0004]

In order to make the total thickness of the entire tape uniform, the present inventor has provided a depression in the substrate, and in the depression and / or on the surface of the substrate opposite to the depression. ,
By arranging the adhesive, the above problem has been solved.

That is, the present invention is as follows. A pressure-sensitive adhesive tape having a pressure-sensitive adhesive tape partially having a region where a pressure-sensitive adhesive is arranged in a width direction of a surface of a tape substrate, wherein a concave portion is formed on one or both surfaces of the substrate in a pressure-sensitive adhesive applied region. An adhesive tape in which a concave portion is formed on a surface of a tape substrate on which an adhesive is disposed. An adhesive tape having a concave portion formed on a surface opposite to a surface of a tape substrate on which an adhesive is disposed. An adhesive tape in which concave portions are formed on both sides of a tape base on which an adhesive is disposed. The depth of the recess (based on the surface of the base material; however, when recesses are formed on both sides of the opposite portion of the tape base material, the sum of the depths of the recesses on the opposite sides) An adhesive tape having a thickness of 0.1 to 1.2 times the thickness of the adhesive layer.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The substrate used in the present invention is not particularly limited, and examples thereof include plastic substrates such as polypropylene, polyester, polyethylene and polyvinyl chloride. The substrate used in the present invention may be subjected to a back surface treatment or an undercoat, if necessary. For the back surface treatment, a long-chain alkyl-based release agent or a silicone-based release agent is used. The thickness of the substrate used in the present invention is usually about 10 to 150 μm, preferably 2 to 150 μm.
0 to 60 μm.

The recesses formed on the surface of the substrate are generally continuous in the longitudinal direction (longitudinal direction) of the tape, but may be intermittent at predetermined intervals. The recess is
The tape is provided on the surface of the tape substrate on which the pressure-sensitive adhesive is applied and / or on the surface opposite to the surface, on which the pressure-sensitive adhesive is applied in the width direction of the surface of the tape substrate. However, the area where the pressure-sensitive adhesive is applied in the width direction of the surface of the tape base material (adhesive application area) is not limited to the area where the applied pressure-sensitive adhesive actually occupies the surface of the tape base material. It may be somewhat wide or narrow.

As a method of forming a concave portion on the surface of the tape substrate, for example, the following method can be mentioned. Heat is applied partially to the plastic substrate, and then it is stretched in the width direction to stretch only the heated portions. The stretched portion has a reduced thickness, and the thinned portion constitutes a concave portion in the present invention. When extruding a base material, a die in which a part of the extruded base material in the width direction is thinned is attached in advance to the exit end of the extruder, and the molten resin is extruded to form a thin film portion. This thin film portion constitutes the concave portion in the present invention. The plastic substrate is pressed with a hot roll having a width smaller than the width of the substrate, so that a part of the surface of the substrate is physically recessed. This depression constitutes the concave portion in the present invention.

The pressure-sensitive adhesive used in the present invention is not particularly limited, and a known pressure-sensitive adhesive can be appropriately selected and used. For example, a rubber-based adhesive, an acrylic-based adhesive, and a silicone-based adhesive can be used.

As the rubber-based pressure-sensitive adhesive, any of a natural rubber-based pressure-sensitive adhesive and a synthetic rubber-based pressure-sensitive adhesive may be used. Examples of the synthetic rubber-based adhesive include styrene-isoprene block copolymer (SIS), styrene-butadiene rubber (SBR),
Isoprene rubber (IR), polyisobutylene (PI
B) and an adhesive mainly composed of a rubber-based polymer such as butyl rubber (IIR).

Examples of the acrylic pressure-sensitive adhesive include alkyl (meth) acrylate monomers such as ethyl acrylate, methyl methacrylate, 2-hydroxyethyl acrylate, butyl acrylate, and 2-ethylhexyl acrylate, acrylic acid, methacrylic acid, and itacone. A homopolymer or a copolymer of an acrylic monomer such as a carboxyl group-containing monomer such as an acid, maleic acid, and crotonic acid may be used. Further, copolymers of these monomers and monomers copolymerizable with the monomers are also included. Specifically, an alkyl ester polymer such as acrylic acid or methacrylic acid, or an alkyl ester polymer such as acrylic acid or methacrylic acid
Acrylic polymer having an average molecular weight of 5,000 to 3,000,000, comprising a copolymer of 99.5% by weight and 0.5 to 50% by weight of another copolymerizable unsaturated monomer. And the like. Polymerization is not particularly limited, for example, solution polymerization, emulsion polymerization,
Examples include bulk polymerization and suspension polymerization.

Examples of the silicone-based pressure-sensitive adhesive include known silicone-based pressure-sensitive adhesives such as a peroxide-crosslinkable silicone-based pressure-sensitive adhesive and a hydrosilyl-type (addition-reaction-type) silicone-based pressure-sensitive adhesive.

The pressure-sensitive adhesive may be, if necessary, a tackifier such as a petroleum resin, a terpene resin, a rosin resin, a cumarone resin, a crosslinking agent, a tackifier, a softener, an antioxidant, a filler, a release agent, or the like. Known additives such as a mold agent, a plasticizer, a stabilizer, a pigment, and an antioxidant may be blended.

The application of the pressure-sensitive adhesive to the substrate may be performed by a method known per se. For example, there is a method in which the above-mentioned pressure-sensitive adhesive is dissolved in a solvent such as toluene or ethyl acetate, and the obtained pressure-sensitive adhesive solution is applied using a roll coater, a gravure coater, a kiss coater, or the like. The thickness (after drying) of the pressure-sensitive adhesive layer is appropriately determined depending on the purpose, and is usually 5 to 1
It is about 00 μm, preferably 10 to 40 μm. However, when the pressure-sensitive adhesive is applied to the surface of the substrate, that is, when the pressure-sensitive adhesive is applied to the concave portion formed on the surface of the substrate, the thickness of the pressure-sensitive adhesive layer (after drying) is 5 to 100 μm.
m, and preferably about 10 to 40 μm.

In the width direction of the surface of the tape substrate, the ratio of the area where the adhesive is applied to the area where the adhesive is not applied is usually 0.1: 99.9 to 50:50. , Preferably 1:99 to 20:80. When the pressure-sensitive adhesive is applied to the concave portion formed on the surface of the base material, the depth of the concave portion is preferably 0.1 to 1.2 times the thickness of the pressure-sensitive adhesive layer, and particularly preferably 0.8 to 1. 2 times, further 0.9 times to 1.1 times
Double is more preferred. In addition, the reference of this depth is based on the surface of the base material. Further, the case where concave portions are formed on both surfaces of the opposite portion of the tape base material and the case where an adhesive region is formed in the concave portions of the opposite both surfaces (FIG. 4)
In the embodiment, the depth of each of the recesses may be the thickness described above, and the recesses are formed on both opposing surfaces, and the pressure-sensitive adhesive region is formed only on the recesses on one side ( In the embodiment of FIG. 3), the thickness of 0.8 to 1.2 times refers to the sum of the depths of the concave portions on the opposite surfaces.

The pressure-sensitive adhesive tape of the present invention can be obtained by applying a pressure-sensitive adhesive to at least one surface of the above-mentioned substrate and providing a pressure-sensitive adhesive layer. The pressure-sensitive adhesive tape of the present invention can be formed into a double-sided pressure-sensitive adhesive tape by providing a pressure-sensitive adhesive layer in concave portions formed on both surfaces of the substrate. When providing the pressure-sensitive adhesive layer on both sides of the substrate, for example, directly apply the pressure-sensitive adhesive to the recesses formed on both sides of the substrate to form the pressure-sensitive adhesive layer, or on the release paper facing the recesses of the substrate A method in which an adhesive is applied to the position and dried to form an adhesive layer on release paper in advance, and then the adhesive layer is transferred to a concave portion on the surface of the base material may be adopted.

[0017]

EXAMPLES Examples and comparative examples of the present invention are shown below, but the present invention is not limited by these examples.

Example 1 A polyethylene film having a concave portion (thickness: 20 μm) was obtained as shown in FIG. 1 by melt-extruding polyethylene using a T-die. The depth (a) of the concave portion was 4 μm. A natural rubber-based pressure-sensitive adhesive is applied to the recess by a die coater to form a natural rubber-based pressure-sensitive adhesive layer, and the pressure-sensitive adhesive tape partially has a region (A) to which the pressure-sensitive adhesive is applied in the width direction Was prepared. The thickness (b) of the natural rubber-based pressure-sensitive adhesive layer is 40 μm
Met.

Example 2 An adhesive tape shown in FIG. 2 was produced in the same manner as in Example 1 except that a natural rubber-based pressure-sensitive adhesive layer (40 μm in thickness) was formed on the substrate surface opposite to the concave portion.

Example 3 As shown in FIG. 3, a biaxially oriented polypropylene film (40 μm thick) as a substrate
The film was partially heated, pulled in the width direction, and only the heated portion was stretched to form recesses on both surfaces of the film. The depth (a) of each recess was 20 μm. A natural rubber-based pressure-sensitive adhesive is applied to each of the concave portions by a die coater to form a natural rubber-based pressure-sensitive adhesive layer, and the pressure-sensitive adhesive partially has a region (A) where the pressure-sensitive adhesive is applied in the width direction. A tape was made. The thickness (b) of the natural rubber-based pressure-sensitive adhesive layer is 17 μm.
m.

[Comparative Example] A biaxially oriented polypropylene film having a width of 50 mm (thickness: 40 μm) was measured from the end in the width direction by 2 mm.
0mm part, width 10mm and thickness 3 centered here
An adhesive layer having a thickness of 0 μm was formed to produce an adhesive tape. As the pressure-sensitive adhesive, a natural rubber-based pressure-sensitive adhesive was used, and the application was performed with a die coater.

[Test Example] Each of the sheets obtained in the above Examples and Comparative Examples was wound at a high speed, and the evaluation of the winding deviation when the tape was held under the following conditions was evaluated. The evaluation was performed by leaving the wound tape at 40 ° C. for 3 days and determining the amount of side displacement. Table 1 shows “○” when the amount of deviation of the side face is less than 1.0 mm, “Δ” when it is 1.0 mm or more and 2.0 or less, and “×” when it is 2.1 or more.

[0023]

[Table 1]

[0024]

According to the pressure-sensitive adhesive tape of the present invention, even if a high pressure is applied, the force is dispersed over the entire width of the tape, and the pressure-sensitive adhesive is fixed in the concave portion, so that the winding deviation is very unlikely to occur. Therefore, when the coating speed is increased and the tension applied to the tape is increased, or when the tape is wound in a stored state, the tape is hardly displaced. Further, even when the tape winding length is long, it is possible to obtain a product which is very stable and does not easily cause a winding deviation.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view in the width direction of an adhesive tape of Example 1.

FIG. 2 is a cross-sectional view in the width direction of the pressure-sensitive adhesive tape of Example 2.

FIG. 3 is a cross-sectional view in the width direction of the pressure-sensitive adhesive tape of Example 3.

[Explanation of symbols]

 A: adhesive application area a: depth of concave portion b: thickness of adhesive layer

Claims (5)

[Claims] 1. A pressure-sensitive adhesive tape partially having a region in which a pressure-sensitive adhesive is arranged in a width direction of a surface of a tape substrate, wherein a concave portion is formed on one or both surfaces of the substrate in a pressure-sensitive adhesive applied region. . 2. The pressure-sensitive adhesive tape according to claim 1, wherein a concave portion is formed on the surface of the tape substrate on which the pressure-sensitive adhesive is disposed. 3. The pressure-sensitive adhesive tape according to claim 1, wherein a concave portion is formed on a surface opposite to a surface of the tape substrate on which the pressure-sensitive adhesive is disposed. 4. The pressure-sensitive adhesive tape according to claim 1, wherein concave portions are formed on both surfaces of the tape substrate on which the pressure-sensitive adhesive is disposed. 5. The pressure-sensitive adhesive tape according to claim 1, wherein the depth of the concave portion is 0.1 to 1.2 times the thickness of the pressure-sensitive adhesive layer.