JPH09316405A - Adhesive tape - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prepare an adhesive tape that has sufficient unwinding properties and manual tearability, and is hard to break when the tape is peeled off after being applied once, without diminishing its adhesive properties, by adjusting the viscosity of the adhesive applied to a substrate having through pores. SOLUTION: This adhesive tape comprises a substrate having a number of through pores having 0.1-300μm in average opening size, and a layer which is composed of an adhesive having kinetic viscosity of 2×104 poise or more at 50 deg.C formed at least on one face of the substrate. In this adhesive tape, preferably, the adhesive comprises at least one of acrylate-, rubber-, silicone- and vinylacetate-based adhesives, the adhesive layer has a thickness of 20-70μm, and the substrate is a plastic film or a composite of a plastic film and a metal, and has through pores in density of 200 pores/cm<2> .

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an adhesive tape. More specifically, the present invention relates to an adhesive tape which has good rewindability and hand tearability when it is used (it can be easily cut by hand), and which does not tear when it is peeled off after being applied. .

[0002]

2. Description of the Related Art Adhesive tapes have a rewinding property when they are attached (ease of pulling out a tape use portion when grasping and pulling an end portion of a tape wound in a roll shape). ) Is good, it is easily cut by hand, its cut surface is clean, and when it becomes necessary to peel off after fulfilling the purpose, the tape is required to be easily peeled without breaking in the middle . In particular, a worker at a construction site or the like often uses an adhesive tape to perform a manual work, and the tape is required to have strength without being stretched when it is attached and to be easily cut by hand.

As the base material of such an adhesive tape, materials such as paper, polyvinyl chloride, polyethylene, polypropylene and polyester are mentioned, which are processed into various shapes and used. For example, conventionally, as a constitution of an adhesive tape, a pressure sensitive adhesive is applied to a base material such as a uniaxially-stretched polypropylene base material, a polyethylene cloth base material and a polyethylene cut base material which can be easily cut by hand, and the opposite surface is coated. The thing which carried out the mold release process has been used many times.

However, in the case of a uniaxially stretched polypropylene base material, there is a problem that the adhesive tape has to be cut by applying an impact, and it is difficult to cut and it is necessary to get used to it. In this case, there was a problem that so-called "beard" was liable to appear on the cut surface. Further, in the case of a polyethylene cut processed base material, since the base material itself has deep unevenness, there is a problem that it is easy to cut when the tape is rewound or peeled.

[0005] Further, there has been proposed a method in which a base material is perforated by a needle punch method or the like to improve the cut of the base material. There was a problem that the adhesive tape could not be smoothly rewound due to strike-through on the side opposite to the agent-coated surface.

An object of the present invention is to provide a pressure-sensitive adhesive tape which has good rewindability, good hand tearability, and does not easily tear during peeling without deteriorating the adhesive property.

[0007]

Means for Solving the Problems As a result of intensive studies to achieve the above object, the present inventors have adjusted the viscosity of a pressure-sensitive adhesive applied to a substrate having through holes to a specific range. As a result, they have found that the above object is achieved, and have completed the present invention.

That is, according to the present invention, (1) the average opening diameter is 0.
An adhesive tape comprising a substrate having a large number of through holes of 1 to 300 μm and a layer of an adhesive having a dynamic viscosity at 50 ° C. of 2 × 10 ⁴ poise or more formed on at least one surface of the substrate, (2) The pressure-sensitive adhesive tape according to (1) above, wherein the pressure-sensitive adhesive is at least one kind of pressure-sensitive adhesive selected from the group consisting of acrylic pressure-sensitive adhesives, rubber pressure-sensitive adhesives, silicone pressure-sensitive adhesives and vinyl acetate pressure-sensitive adhesives. (3) The pressure-sensitive adhesive tape according to (1) above, wherein the thickness of the pressure-sensitive adhesive layer is 20 to 70 μm, and (4) the base material is a plastic film or a composite base material of a plastic film and a metal (1). pressure-sensitive adhesive tape according, and (5) base material, it relates to a pressure-sensitive adhesive tape of the above (1), wherein those having a through hole 200 / cm ² or more.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The pressure-sensitive adhesive used in the present invention is adjusted to have a specific dynamic viscosity in order to prevent strike-through during storage after being made into a pressure-sensitive adhesive tape. That is, considering the long-term storage stability at a temperature practical for an adhesive tape, the dynamic viscosity at 50 ° C. needs to be 2 × 10 ⁴ poises or more. Preferably 2 × 10 ⁴ to 8 × 10 ⁴ poises,
More preferably, it is 3 × 10 ^{4 to} 5 × 10 ⁴ poise.
When the dynamic viscosity is less than 2 × 10 ⁴ poise, strike-through easily occurs during long-term storage when used as an adhesive tape. The dynamic viscosity is RDS-I, a rheometric viscoelasticity measuring device.
It is a value measured using I (temperature: 50 ° C., frequency: 1 Hz).

The adhesive used in the present invention is 50
There is no particular limitation as long as it has a dynamic viscosity at 2 ° C. of 2 × 10 ⁴ poise or more. For example, rubber adhesive,
Examples thereof include acrylic adhesives, silicone adhesives, vinyl acetate adhesives, and the like.

As the rubber adhesive, either a natural rubber adhesive or a synthetic rubber 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), butyl rubber (IIR) and the like. These are used alone or as a mixture of two or more kinds.

Examples of the acrylic adhesive include (meth) acrylic acid alkyl ester monomers such as ethyl acrylate, methyl methacrylate, 2-hydroxyethyl acrylate, butyl acrylate, and 2-ethylhexyl acrylate, acrylic acid, methacrylic acid, and itacone. Examples thereof include homopolymers or copolymers of acrylic monomers such as carboxyl group-containing monomers such as acid, maleic acid and crotonic acid. Further, a copolymer of the acrylic monomer and a monomer copolymerizable with the monomer may also be used. The polymerization is not particularly limited, and examples thereof include solution polymerization, emulsion polymerization, bulk polymerization and suspension polymerization. Among them, acrylic pressure-sensitive adhesives are excellent in heat resistance and weather resistance.

If necessary, the pressure-sensitive adhesive may be a cross-linking agent,
Known additives such as tackifiers, softeners, antioxidants, fillers, release agents, tackifiers, plasticizers, stabilizers, pigments, and antioxidants may be blended.

The pressure-sensitive adhesive layer may be provided on at least one side of the base material. The thickness (after drying) of the pressure-sensitive adhesive layer is appropriately determined according to the purpose and is about 20 to 70 μm.
It is preferably 30 to 50 μm.

In the present invention, a plastic film is preferably used as the substrate. Examples include polyethylene, polypropylene, polyvinyl chloride and polyester.

Further, a composite substrate of a plastic film and a metal can also be preferably used. For example, a metal foil may be laminated on a plastic film, or a metal vapor deposition film may be used. Examples of metals include gold, silver,
Examples include copper and aluminum.

The base material used in the present invention has a large number of fine through holes, and the average opening diameter of the holes is 0.1 to 300 μm.
m, and preferably 0.1 to 100 μm.

When the average opening diameter is 0.1 to 300 μm, the adhesive tape has good hand-cutability, and the adhesive passes through the opposite side of the adhesive-coated surface or the release agent adheres through the holes. There is no transfer to the agent, and as a result, the adhesive property is not deteriorated, the smoothness of the adhesive surface is not deteriorated, and the rewinding property of the tape is not deteriorated. In addition, it does not become easier to tear than necessary during peeling.

The density of fine through-holes on the substrate is preferably 200 holes / cm ² or more, more preferably 500 holes / cm ^2.
cm ² or more. There is no special upper limit. When the density of the through holes is 200 / cm ² or more, the adhesive tape has good hand-cutability when cut, and the cut surface is also good.

The thickness of the substrate is not particularly limited, but is usually 2
It is about 0 to 150 μm, preferably 30 to 120 μm.

The substrate used in the present invention may be subjected to back treatment or undercoating if necessary.

The adhesive tape may be manufactured by a method known per se. For example, a film formed by heat fusion perforation, or a film mechanically perforated by a roll having a large number of synthetic diamond particles attached, an adhesive is applied using a reverse coater or the like, Examples include a method of drying.

[0023]

EXAMPLES Examples and comparative examples are shown below, but the present invention is not limited thereto. Table 1 shows the composition of the acrylic pressure-sensitive adhesive used in Examples and Comparative Examples.

[0024]

[Table 1]

Example 1 A porous film was prepared in which a polypropylene film of 50 μm having both sides corona-treated was provided with 700 through holes having an average opening diameter of 20 μm / cm ² by a mechanical perforation method. The acrylic pressure-sensitive adhesive A in Table 1 was diluted with toluene to a solid content of 40% by weight, and coated on the film so that the thickness after drying was 20 μm. A silicone-based release agent was applied to the above to prepare an adhesive tape.

Example 2 A polyethylene / polypropylene blend film having a corona treated surface on both sides of 50 μm was provided with 2,000 through holes having an average opening diameter of 50 μm / cm ² by a mechanical perforation method to prepare a porous film. . On the film, Table 1
Of acrylic adhesive B of toluene with a solid content of 40% by weight
To a thickness of 40 μm after drying, and a silicone-based release agent was applied to the surface opposite to the adhesive-coated surface to prepare an adhesive tape.

Example 3 An adhesive tape was prepared in the same manner as in Example 2 except that a 38 μm polyester (PET) film was used.

Example 4 An adhesive tape was prepared in the same manner as in Example 3 except that the average opening diameter was 0.2 μm.

Example 5 An adhesive tape was prepared in the same manner as in Example 3 except that the average opening diameter was 250 μm.

Comparative Example 1 An adhesive tape was prepared in the same manner as in Example 1 except that a uniaxially stretched polypropylene film of 60 μm with no holes was used as the base material.

Comparative Example 2 A polypropylene film of 50 μm having both sides corona-treated was provided with 700 through holes having an average opening diameter of 50 μm / cm ² by a mechanical perforation method to prepare a porous film. Acrylic pressure-sensitive adhesive C in Table 1 was diluted with toluene to a solid content of 40% by weight, and coated on the film so that the thickness after drying was 20 μm. A silicone-based release agent was applied to the above to prepare an adhesive tape.

COMPARATIVE EXAMPLE 3 A porous film was prepared by forming 700 through holes having an average opening diameter of 400 μm / cm ² by a mechanical perforation method in a polypropylene film of 50 μm whose both surfaces were corona treated. The acrylic pressure-sensitive adhesive A in Table 1 was diluted with toluene to a solid content of 40% by weight, and coated on the film so that the thickness after drying was 20 μm. A silicone-based release agent was applied to the above to prepare an adhesive tape.

Using the substrates and pressure-sensitive adhesive tapes obtained in Examples 1 to 5 and Comparative Examples 1 to 3 as samples, the adhesive strength, the hand-cutability in the width direction at the time of tape attachment and the cleanliness of the cut surface, the warp were measured. The rewinding property after storage for a day and the tearing property at the time of tape peeling were evaluated. Each evaluation method is as follows.

[Adhesive strength] A stainless steel plate (SUS304B) prepared by previously washing a 20 mm wide adhesive tape with toluene.
In A), the sample was left for 30 minutes at 23 ° C. × 60% RH with a rubber roller and left for 30 minutes. The resistance when the sample was peeled off in the direction of 180 ° was measured as an adhesive force with a universal tensile tester (RTM-100, manufactured by Orientec Co., Ltd.).

[Hand-cutability in the width direction when tape is attached and cleanliness of cut surface] The edge of the adhesive tape is torn in the direction of 180 ° at a speed of 30 m / min to make the hand-cutability in the width direction of the adhesive tape. confirmed. The cleanness of the cut surface at that time was also confirmed. The evaluation is as follows. ◯: The tape base material was easily cut without extending during cutting. Δ: The cutting is not so good, but you can work if you get used to it. X: It is difficult to tear the tape base material during cutting, and the cut surface is not messy.

[Tearability during tape peeling] 20 mm for flooring
Stick a width of adhesive tape (20 cm in length) and put it at room temperature for 1
After leaving for a week, the tearability of the tape was confirmed when the adhesive tape was peeled off in the 180 ° direction at a speed of 30 m / min. ：: The tape substrate was not broken at the time of peeling, and could be easily peeled. X: The tape substrate was torn at the time of peeling, and peeling was difficult.

[Rewinding characteristics after storage over time] The adhesive tape was stored in a rolled state at 50 ° C for 20 days, and the strikethrough of the adhesive was confirmed when the adhesive tape was rewound at room temperature. ◯: There was no strike through of the pressure-sensitive adhesive, and the film could be smoothly rewound during rewinding. X: There was strike-through of the pressure-sensitive adhesive and it could not be smoothly rewound during rewinding.

[Dynamic Viscosity] A dynamic viscosity was measured at a frequency of 1 Hz using a rheometric viscoelasticity measuring apparatus RDS-II.

Table 2 shows the above measurement results.

[0040]

[Table 2]

[0041]

EFFECT OF THE INVENTION The adhesive tape of the present invention has good rewindability and hand tearability without deteriorating the adhesive property,
Hard to tear when peeled. Therefore, it can be suitably used as an adhesive tape.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical location C09J 7/02 JJW C09J 7/02 JJW JJX JJX JJY JJY JKD JKD (72) Inventor Koichi Ikeda Osaka Nitto Denko Co., Ltd. 1-2 1-2 Shimohozumi, Ibaraki-shi, Japan

Claims (5)

[Claims] 1. A base material having a large number of through holes having an average opening diameter of 0.1 to 300 μm, and a dynamic viscosity at 50 ° C. formed on at least one surface of the base material is 2 × 10 ⁴ poises or more. An adhesive tape containing a layer of an adhesive. 2. The pressure-sensitive adhesive tape according to claim 1, wherein the pressure-sensitive adhesive is at least one pressure-sensitive adhesive selected from the group consisting of acrylic pressure-sensitive adhesives, rubber pressure-sensitive adhesives, silicone pressure-sensitive adhesives and vinyl acetate pressure-sensitive adhesives. . 3. The pressure-sensitive adhesive tape according to claim 1, wherein the pressure-sensitive adhesive layer has a thickness of 20 to 70 μm. 4. The substrate is a plastic film or a composite substrate of a plastic film and a metal.
Adhesive tape as described. 5. The adhesive tape according to claim 1, wherein the substrate has 200 through holes / cm ² or more.