WO2014097903A1

WO2014097903A1 - Adhesive tape

Info

Publication number: WO2014097903A1
Application number: PCT/JP2013/082827
Authority: WO
Inventors: 健太定司; 弘宣玉井
Original assignee: 日東電工株式会社
Priority date: 2012-12-21
Filing date: 2013-12-06
Publication date: 2014-06-26
Also published as: JP2014139299A

Abstract

An adhesive tape (10) according to the present invention is provided with a base (30) comprising a metal foil and a rubbery adhesive agent layer (20) arranged on one surface of the base (30), wherein the rubbery adhesive agent layer (20) comprises 100 parts by mass of a natural rubber and 10 to 110 parts by mass of a synthetic rubber.

Description

Adhesive tape

The present invention relates to an adhesive tape.

Conventionally, adhesive tape has been used in various technical fields. For example, as shown in Patent Document 1, in the field of car body painting such as automobiles, an adhesive tape is used in order to prevent the paint from adhering to a non-painted portion that does not require painting. This type of adhesive tape is generally referred to as a masking tape or the like, and is used by being affixed to an unpainted portion of the vehicle body during painting. In addition, after completion | finish of coating, an adhesive tape is peeled and removed from a vehicle body.

JP 2001-55549 A

(Problems to be solved by the invention)
By the way, in the field of airframe coating such as aircraft, adhesive tape is used not only when the airframe is painted but also when the paint is peeled off from the airframe. In this field, the aircraft is regularly repainted for maintenance and other purposes. And as a part of the repainting work, the work which peels off the paint which has already been painted on the airframe using a chemical solution is performed.

During such peeling work, if chemicals adhere to the window of the machine, the attached part may be corroded. Therefore, the peeling operation as described above is performed in a state in which a cover (so-called masking material) made of aluminum foil or the like is provided in advance on the body portion that is easily corroded. The adhesive tape is used for attaching an aluminum foil covering a window or the like to the airframe. At that time, the adhesive tape borders the periphery of the aluminum foil and the body part exposed from the periphery (for example, the window frame) while framing the periphery of the aluminum foil arranged in a form covering the window, Affixed to the aircraft part. In addition, the adhesive tape affixed on the said body part is peeled off with aluminum foil suitably after a peeling operation | work and other operations after that.

As described above, when the adhesive tape is peeled off from the adherend such as the airframe after the paint is peeled off, a part of the adhesive may remain on the adherend side. The pressure-sensitive adhesive remaining on the adherend side causes dirt on the adherend such as the airframe and poor coating, and therefore has to be removed from the adherend, which is a problem.

This invention makes it a subject to solve the said various problems in the past and to achieve the following objectives. That is, an object of the present invention is to provide a pressure-sensitive adhesive tape in which the pressure-sensitive adhesive is suppressed or prevented from remaining on the adherend after peeling.

(Means for solving the problem)
As a result of intensive studies to achieve the above object, the present inventor has a base material made of a metal foil and a rubber-based pressure-sensitive adhesive layer provided on one surface of the base material, and the rubber-based pressure-sensitive adhesive. The layer has been found that an adhesive tape containing 100 parts by mass of natural rubber and 10 to 110 parts by mass of synthetic rubber suppresses or prevents the adhesive from remaining on the adherend after peeling. It came to.

In the pressure-sensitive adhesive tape, the rubber-based pressure-sensitive adhesive layer preferably contains a styrene-isoprene-styrene block copolymer as the synthetic rubber.

In the pressure-sensitive adhesive tape, the rubber-based pressure-sensitive adhesive layer preferably contains a tackifier.

In the adhesive tape, the rubber adhesive layer preferably contains a petroleum resin and a rosin resin as the tackifier.

In the pressure-sensitive adhesive tape, the rubber-based pressure-sensitive adhesive layer preferably contains 1 to 10 parts by mass of a crosslinking agent made of aromatic isocyanate.

In the adhesive tape, the rubber adhesive layer preferably has a thickness of 5 μm to 60 μm.

In the adhesive tape, the metal foil is preferably made of an aluminum foil.

In the pressure-sensitive adhesive tape, it is preferable that an undercoat layer is provided between the base material and the rubber-based pressure-sensitive adhesive layer.

In the pressure-sensitive adhesive tape, it is preferable for masking to be affixed to an untreated portion of the adherend.

In the pressure-sensitive adhesive tape, it is preferable that the adhesive tape is pasted across the peripheral edge of the masking material arranged so as to cover the non-processed part of the adherend and the non-processed part exposed from the masking material.

(The invention's effect)
ADVANTAGE OF THE INVENTION According to this invention, the adhesive tape by which the adhesive remained in the adherend after peeling was suppressed thru | or prevented can be provided.

Schematic sectional view of the adhesive tape of Example 1

The pressure-sensitive adhesive tape according to the present embodiment includes a base material made of a metal foil and a rubber-based pressure-sensitive adhesive layer (hereinafter sometimes simply referred to as a pressure-sensitive adhesive layer) formed on one surface of the base material. . In general, the “adhesive tape” may be called by a name different from “adhesive sheet”, “adhesive film”, etc., but in this specification, the expression is unified as “adhesive tape”. Further, the surface of the pressure-sensitive adhesive layer in the pressure-sensitive adhesive tape may be referred to as “pressure-sensitive adhesive surface”.

In addition, the pressure-sensitive adhesive tape of this embodiment may include other layers (for example, an intermediate layer and an undercoat layer) as long as the object of the present invention can be achieved, in addition to the pressure-sensitive adhesive layer and the base material. Hereinafter, each part which comprises an adhesive tape is demonstrated.

(Rubber adhesive layer)
The rubber-based pressure-sensitive adhesive layer is a layer that is provided on one surface of the substrate and provides the pressure-sensitive adhesive surface of the pressure-sensitive adhesive sheet. The rubber-based pressure-sensitive adhesive layer comprises at least natural rubber and synthetic rubber. Further, the rubber-based pressure-sensitive adhesive layer may contain a tackifier and other components as necessary.

<Natural rubber>
The natural rubber used for the rubber-based pressure-sensitive adhesive layer is not particularly limited, and natural rubber that has been kneaded with a kneading roll and adjusted to have a Mooney viscosity of, for example, about 10 to 100 is used.

<Synthetic rubber>
Examples of the synthetic rubber used for the rubber-based pressure-sensitive adhesive layer include styrene-isoprene-styrene block copolymer (SIS), styrene-butadiene-styrene block copolymer (SBS), and hydrogen of the styrene block copolymer. Examples thereof include additives, styrene-butadiene rubber (SBR), polyisoprene rubber (IR), polyisobutylene (PIB), butyl rubber (IIR), and butyl rubber (IIR). These synthetic rubbers may be used alone or in combination of two or more. Among these, SIS is particularly preferable as a synthetic rubber used for the rubber-based pressure-sensitive adhesive layer from the viewpoints of adhesive strength, holding power, good peelability, and the like.

SIS is preferably a polymer having a radial structure and containing 10 to 40% by mass, preferably 15 to 45% by mass of styrene as a constituent monomer. As what is marketed as such SIS, a brand name "Quintac 3460C" (made by Nippon Zeon Co., Ltd.) is mentioned, for example. The styrene content in SIS refers to the mass proportion of the styrene component in the total mass of the block copolymer, and can be measured by NMR (nuclear magnetic resonance spectroscopy).

The compounding amount of the synthetic rubber is 10 to 110 parts by mass, preferably 15 to 80 parts by mass with respect to 100 parts by mass of natural rubber.

The ratio of the total amount of natural rubber and synthetic rubber in the rubber-based pressure-sensitive adhesive layer is not particularly limited, but is preferably 30 to 90% by mass, more preferably 40 to 80% by mass, and still more preferably 40 to 70% by mass.

<Tackifier>
The rubber-based pressure-sensitive adhesive layer may contain a tackifier in addition to the natural rubber and the synthetic rubber. Examples of the tackifier include rosin resins, terpene resins, petroleum resins, and the like.

Examples of the rosin resins include disproportionated rosin, hydrogenated rosin, polymerized rosin, maleated rosin, fumarated rosin and other rosin derivatives, phenol-modified rosin, and rosin ester.

Examples of the phenol-modified rosin include those obtained by adding a phenol to a natural rosin or rosin derivative, or a phenol-modified rosin obtained by reacting a resole-type phenol resin with a natural rosin or rosin derivative. It is done. Phenol-modified rosin can be used as a metal salt.

Examples of the rosin ester include esterified products obtained by reacting the rosin resin with a polyhydric alcohol. Note that the rosin phenol resin may be an esterified product.

Examples of terpene resins include terpene resins, terpene phenol resins, aromatic modified terpene resins, hydrogenated terpene resins, and the like.

Examples of petroleum resins include aliphatic petroleum resins, aromatic petroleum resins, copolymer petroleum resins, hydrogenated petroleum resins, and the like. An aliphatic petroleum resin is a resin obtained by cationic polymerization of a C5 fraction of naphtha cracked oil, and an aromatic petroleum resin is a resin obtained by cationic polymerization of a C9 fraction of naphtha cracked oil. The petroleum-based petroleum resin is a resin obtained by cationic polymerization of a C5-C9 fraction of naphtha cracked oil, and the hydrogenated petroleum resin is a hydride of an aromatic petroleum resin or a dicyclopentadiene-based thermal polymerization resin.

The tackifiers may be used alone or in combination of two or more. Examples of commercially available tackifiers include trade name "Quinton D-200" (maleic anhydride modified C5, C9 resin, manufactured by Nippon Zeon Co., Ltd., copolymer petroleum resin), trade name “Sumilite PR12603N” (phenol modified rosin, manufactured by Sumitomo Bakelite Co., Ltd., an example of rosin resin), and the like. As the tackifier, a combination of petroleum resin and rosin resin is most preferable.

The compounding amount of the tackifier can be appropriately selected within a range not impairing the adhesive performance of the rubber-based adhesive layer. For example, the total amount is 20 to 150 parts by mass with respect to 100 parts by mass of natural rubber. The amount is preferably 30 to 120 parts by mass, and more preferably 40 to 100 parts by mass.

<Other ingredients>
In addition to the components described above, the rubber-based pressure-sensitive adhesive layer is a softener, a plasticizer, a filler, an antioxidant, an anti-aging agent, a cross-linking agent, a solvent, and a coloring agent as long as the object of the present invention can be achieved. Additives such as agents may be included.

The cross-linking agent is blended in the rubber-based pressure-sensitive adhesive layer for the purpose of adjusting the cohesive force and the like. As said crosslinking agent, an isocyanate type crosslinking agent is preferable and especially aromatic isocyanate is preferable. As what is marketed as such an aromatic isocyanate, a brand name "Coronate L" (made by Nippon Polyurethane Co., Ltd.) is mentioned, for example. The amount of the crosslinking agent is 0.1 to 10 parts by weight, preferably 1 to 8 parts by weight, based on 100 parts by weight of natural rubber.

The anti-aging agent is preferably a phenol-based anti-aging agent, and the blending amount of the anti-aging agent is preferably 0.1 to 10 parts by mass, and 0.5 to 5 parts by mass with respect to 100 parts by mass of natural rubber. Is more preferable. An example of such an anti-aging agent marketed is “NOCRACK NS-6” (manufactured by Ouchi Shinsei Chemical Industry Co., Ltd.).

<Thickness of rubber adhesive layer>
The thickness of the rubber-based pressure-sensitive adhesive layer is not particularly limited and is appropriately set according to the purpose. For example, in the masking application, 5 μm to 60 μm is preferable, and 20 μm to 40 μm is more preferable.

(Base material)
As a base material, metal foil bodies (metal foil), such as aluminum, copper, silver, iron, nickel, tin, stainless steel, are used, for example. The metal foil is preferably a soft metal foil such as soft aluminum. Since the pressure-sensitive adhesive tape of this embodiment includes such a metal foil as a base material, a liquid (for example, a chemical solution for peeling off the coating) is infiltrated into the base material when the adhesive tape is used or stored. The material is prevented from being destroyed. Therefore, for example, after being attached to the adherend, it is possible to prevent the base material from being destroyed and the adhesive tape (adhesive layer) from being peeled off from the adherend. In addition, since the substrate made of a soft metal foil has particularly high followability to the surface shape of the adherend, the adhesive layer supported by the substrate is covered when the adhesive tape is attached to the adherend. It is easy to follow and adhere to the body. The thickness of the substrate is preferably 10 μm to 300 μm, and more preferably 25 μm to 100 μm.

(Undercoat layer)
The pressure-sensitive adhesive tape may include an undercoat layer between the base material and the rubber-based pressure-sensitive adhesive layer in order to improve the adhesion between the base material and the rubber-based pressure-sensitive adhesive layer. The undercoating agent constituting the undercoating layer is not particularly limited and is appropriately selected from known ones. The thickness of the undercoat layer is not particularly limited, but is preferably 0.01 μm or more and 1 μm or less, more preferably 0.1 μm or more and 1 μm or less.

(Release liner)
In the adhesive tape, the surface (adhesive surface) of the rubber-based adhesive layer may be protected by a release liner until use. The release liner is used as a protective material for the rubber-based pressure-sensitive adhesive layer, and is peeled off when the pressure-sensitive adhesive tape is attached to the adherend. Note that the release liner is not necessarily provided on the adhesive tape. As the release liner, for example, a plastic film or paper having a release agent such as a silicone release agent or a long-chain alkyl release agent coated on the surface can be used.

(Manufacturing method of adhesive tape)
The pressure-sensitive adhesive tape of this embodiment is prepared by, for example, dissolving or dispersing each component constituting the rubber-based pressure-sensitive adhesive layer (that is, natural rubber, synthetic rubber and other components) in a solvent such as toluene. The pressure-sensitive adhesive composition is prepared and applied on a substrate, and the applied pressure-sensitive adhesive composition is appropriately dried by a hot air circulation oven or the like. In addition, you may manufacture an adhesive tape by apply | coating the said adhesive composition on a release liner.

The width of the pressure-sensitive adhesive tape of the present embodiment is appropriately set according to the use and is not particularly limited. For example, the width of the adhesive tape used for masking is preferably 5 mm to 200 mm, more preferably 10 mm to 120 mm.

(Peel 180 ° adhesive strength)
The pressure-sensitive adhesive tape of this embodiment is not particularly limited, but preferably has a peel 180 ° adhesive strength of 2.0 N / 20 mm or more (hereinafter sometimes simply referred to as adhesive strength), 3.0 to 40 N / 20 mm is more preferable, 4.0 to 30 N / 20 mm is further preferable, and 5.0 to 20 N / 20 mm is particularly preferable. The said adhesive force can be measured by the method as described in the Example mentioned later.

(Good peelability)
The pressure-sensitive adhesive tape of this embodiment can be peeled off from the adherend without leaving the pressure-sensitive adhesive on the adherend side. That is, the pressure-sensitive adhesive tape of this embodiment does not cause so-called adhesive residue on the adherend after peeling. Thus, the characteristic which can peel an adhesive tape from a to-be-adhered body, without leaving an adhesive on the to-be-adhered body side is called good peelability in this specification. In the pressure-sensitive adhesive tape of this embodiment, the rubber-based pressure-sensitive adhesive layer has an appropriate pressure-sensitive adhesive force, cohesive force, etc., and it is difficult for interlaminar fracture to occur at the time of peeling. Presumed not to remain. The good peelability of the pressure-sensitive adhesive tape is evaluated by visually checking whether or not the pressure-sensitive adhesive remains on the aluminum plate which is a test plate (adhered body) after the measurement of the 180 ° peel adhesive force described above. can do.

(Holding power)
The pressure-sensitive adhesive tape of the present embodiment has a sufficient holding force for masking applications, for example. That is, the pressure-sensitive adhesive tape of the present embodiment has a characteristic that it does not peel off due to its own weight or the like even if it is applied to the adherend for a long time. Furthermore, the pressure-sensitive adhesive tape of this embodiment also has a characteristic that it can be adhered to an adherend for a long time while holding another member (for example, a masking material such as an aluminum foil covering an aircraft window). Yes. The angle at which the adhesive tape for masking application is affixed to the adherend varies. For example, the adhesive tape may be attached to the adherend in a state where the adhesive surface is along the vertical direction, or in the state where the adhesive surface is along the horizontal direction while the base material is disposed on the lower side (the ground side). In some cases, an adhesive tape is attached to the adherend. Under such various circumstances, a holding force that does not peel off from the adherend is required for pressure-sensitive adhesive tapes for masking applications.

The holding power of the adhesive tape can be evaluated by a holding power test according to JIS-Z-0237. Specifically, for example, the pressure-sensitive adhesive tape of this embodiment is pressure-bonded to an aluminum plate (crimping area: 200 mm ² (size 10 mm × 20 mm)), and the aluminum plate is fixed in an atmosphere of 60 ° C. and 50% RH. It can be evaluated by applying a tensile load of 9.8 N to the adhesive tape and measuring the time until the adhesive tape peels off the aluminum plate. As a rule of thumb, if the adhesive tape to which a predetermined tensile load is applied is stuck to the aluminum plate for 20 minutes or more without being peeled off, it can be said that it has sufficient holding power for masking applications and the like.

(Other characteristics)
Moreover, the adhesive tape of this embodiment is provided with characteristics, such as workability (hand-cut property), workability (handleability), durability, and weather resistance. In particular, the pressure-sensitive adhesive tape of this embodiment is excellent in chemical resistance (solvent resistance) because it is made of a rubber-based pressure-sensitive adhesive containing natural rubber, synthetic rubber or the like. Such an adhesive tape of this embodiment can be used for various uses.

(Application of adhesive tape)
The adhesive tape of this embodiment is suitably used for masking applications. The pressure-sensitive adhesive tape of this embodiment is used, for example, to protect a non-painted part (an example of a non-processed part) that is not coated from a paint during a painting operation of a body such as an automobile, a train, a ship, and an aircraft. Moreover, the adhesive tape of this embodiment is preferably used also at the time of the peeling operation | work of the coating using the chemical | medical solution performed as a part of repainting in the said body. At that time, the adhesive tape of the present embodiment uses a chemical solution to remove a non-contact portion (an example of a non-treated portion) that does not come into contact with the chemical solution when the paint is peeled and removed from the already coated body using the chemical solution. Used to protect. The “masking application” in the present specification includes not only the case where the body is coated, but also the case where the paint is peeled off from the body using a chemical solution. In addition, in the “masking use” in the present specification, the case where only the adhesive tape is attached to the non-processed portion where the treatment is not performed and the non-process after the adhesive tape holds the other member covering the non-processed portion. And a case where it is pasted to a location.

In addition, the adhesive tape of the present embodiment is preferably used in masking applications, particularly when the adhesive tape is attached to a non-processed part while holding another member covering the non-processed part. As such a case, for example, a paint peeling operation using a chemical solution performed as part of repainting on an adherend (for example, an aircraft body surface) can be given. During such a peeling operation, the pressure-sensitive adhesive tape of the present embodiment uses a masking material (for example, an aluminum foil) for covering a body portion (for example, an aircraft window, an example of an untreated portion) that is easily corroded. It is used to attach to a metal body). At that time, the adhesive tape borders the periphery of the masking material (for example, aluminum foil) arranged so as to cover a non-processed portion such as a window, and the body portion exposed from the peripheral edge of the masking material (for example, the aluminum foil) , Non-processed portions such as window frames). At that time, the pressure-sensitive adhesive surface of the pressure-sensitive adhesive tape is stuck to the peripheral edge of the masking material and is attached to a part of the non-processed portion exposed from the peripheral edge. That is, the pressure-sensitive adhesive tape is in a state of being attached to a metal body (non-processed portion) that is an adherend while holding the masking material. Since the pressure-sensitive adhesive tape of the present embodiment has an excellent holding force, it can be attached to an adherend while holding the masking material, and thus is preferably used in the peeling operation as described above. The pressure-sensitive adhesive tape attached to the adherend is peeled off and removed together with the masking material (aluminum foil) as appropriate after the peeling operation or after other operations thereafter.

The adhesive tape of this embodiment can also be used as a sealing tape for closing water gaps such as a joint between metal pipes, a kitchen sink, and a fixing tape for a heat radiating pipe, etc. it can.

In the pressure-sensitive adhesive tape of the present embodiment, a preferable adherend is a metal material such as aluminum, iron, and stainless steel, and a particularly preferable adherend is from the viewpoint of the adhesive strength, holding power, and good peelability of the pressure-sensitive adhesive layer. It is an aluminum-based material (including an aluminum alloy). Therefore, when the pressure-sensitive adhesive tape of the present embodiment is used for masking, when the adherend is made of a metal body, various characteristics such as good releasability, adhesive strength, and holding power can be exhibited.

In the pressure-sensitive adhesive tape of the present embodiment, the sticking time on the adherend is not particularly limited and is appropriately set according to the purpose. For example, in the case of a masking application, the sticking time of the adhesive tape is preferably 96 hours or less, more preferably 74 hours or less, and particularly preferably 48 hours or less. If the sticking time of the adhesive tape to the adherend is 98 hours or less, it is possible to prevent the adhesive that can be visually confirmed from remaining on the adherend.

Hereinafter, the present invention will be described in more detail based on examples. In addition, this invention is not limited at all by these Examples.

[Example 1]
(Preparation of rubber-based pressure-sensitive adhesive composition I)
100 parts by weight of natural rubber (Mooney viscosity 75), SIS (made by Nippon Zeon Co., Ltd., trade name “Quintac 3460C”, radial structure SIS, styrene content 25% by weight), 30 parts by weight of maleic anhydride modified C5, C9 resin ( 40 parts by mass of Nippon Zeon Co., Ltd., trade name “Quinton D-200”, 40 parts by mass of phenol-modified rosin (trade name “Sumilite PR12603N”, manufactured by Sumitomo Bakelite Co., Ltd.), and phenolic anti-aging agent (Ouchi Shinsei Chemical Industry) After dissolving 1 part by mass of trade name “NOCRACK NS-6”) in toluene, 3 parts by weight of aromatic isocyanate (trade name “Coronate L”, manufactured by Nippon Polyurethane Co., Ltd.) was added as a crosslinking agent. A solution-like rubber-based pressure-sensitive adhesive composition I was prepared.

(Preparation of adhesive tape 10)
The rubber-based pressure-sensitive adhesive composition I was applied onto a release liner 40 that had been subjected to a release treatment with silicone so that the thickness after drying was 30 μm, and dried in a hot air circulation oven at 100 ° C. for 3 minutes to obtain a solvent, etc. Was removed. Then, by laminating a base material 30 made of a soft aluminum foil (80 μm) on the surface (adhesive surface) of the rubber-based pressure-sensitive adhesive layer 20 made of the dried rubber-based pressure-sensitive adhesive composition I, as shown in FIG. The adhesive tape 10 of Example 1 was obtained.

[Example 2]
(Preparation of primer composition)
60 parts by mass of thermoplastic polyester (trade name “Byron 200” manufactured by Toyobo Co., Ltd.), 40 parts by mass of vinyl chloride-vinyl acetate copolymer (trade name “Solvine M5” manufactured by Nissin Chemical Industry Co., Ltd.), natural 100 parts by mass of a rubber-methyl methacrylic acid copolymer (viscosity 25 ± 10 Pa · s) and 3 parts by mass of a phenolic anti-aging agent (trade name “NOCRACK NS-6” manufactured by Ouchi Shinsei Chemical Industry Co., Ltd.) Undercoating composition was prepared.

(Preparation of adhesive tape 11)
The rubber-based pressure-sensitive adhesive composition I prepared in Example 1 was applied on a release liner that had been subjected to a release treatment with silicone so that the thickness after drying was 30 μm, and the hot-air circulating oven at 100 ° C. for 3 minutes. It dried and removed the solvent. Next, the primer composition was applied to one side of a substrate made of a soft aluminum foil (80 μm) so that the thickness after drying was 1 μm, and dried at 100 ° C. for 2 minutes in a hot air circulation oven. The undercoat layer was formed on one side of the substrate. Thereafter, the base material is laminated so that the undercoat layer overlaps the surface (adhesive surface) of the rubber-based pressure-sensitive adhesive layer made of the dried rubber-based pressure-sensitive adhesive composition I, whereby the pressure-sensitive adhesive of Example 2 having an undercoat layer. Tape 11 was obtained.

[Comparative Example 1]
(Preparation of acrylic pressure-sensitive adhesive composition A)
30 parts by mass of acrylic acid, 1000 parts by mass of n-butyl acrylate, 50 parts by mass of vinyl acetate, 1 part by mass of 2-hydroxyethyl acrylate, and 0.3 parts by mass of 2-mercaptoethanol were mixed with azobisisobutyro Using 1 part by mass of nitrile as a polymerization initiator, solution polymerization was performed in toluene as a polymerization solvent to obtain an acrylic polymer. 3 parts by mass of aromatic isocyanate (trade name “Coronate L”, manufactured by Nippon Polyurethane Co., Ltd.) is added as a cross-linking agent to 135 parts by mass of the solid content of the obtained acrylic polymer, and the mixture is stirred uniformly. Were mixed to prepare a solution-like acrylic pressure-sensitive adhesive composition A.

(Preparation of adhesive tape A)
Acrylic pressure-sensitive adhesive composition A was applied onto a release liner that had been subjected to a release treatment with silicone so that the thickness after drying was 50 μm, and dried in a hot air circulation oven at 100 ° C. for 3 minutes, Removed. Then, the adhesive tape A of Comparative Example 1 was obtained by laminating a base material made of a soft aluminum foil (80 μm) on the surface (adhesive surface) of the adhesive layer made of the dried acrylic pressure-sensitive adhesive composition A. .

[Comparative Example 2]
(Preparation of acrylic pressure-sensitive adhesive composition B)
Polymerization of 3 parts by weight of acrylic acid, 100 parts by weight of n-butyl acrylate, 5 parts by weight of vinyl acetate, 0.1 parts by weight of 2-hydroxyethyl acrylate, and 0.2 parts by weight of azobisisobutyronitrile was started. As an agent, solution polymerization was performed in a mixed solvent of toluene and ethyl acetate (mass ratio: toluene / ethyl acetate = 1/1) to obtain an acrylic polymer. 10 parts by mass of polymerized rosin pentaerythritol ester, 10 parts by mass of hydrogenated rosin glycerin ester, 5 parts by mass of hydrogenated rosin methyl ester, and 15 parts by mass of phenol-modified rosin with respect to 100 parts by mass of the solid content of the obtained acrylic polymer Was added and stirred to obtain a mixture. By adding 3 parts by mass of aromatic isocyanate (trade name “Coronate L”, manufactured by Nippon Polyurethane Co., Ltd.) to 140 parts by mass of the solid content of the obtained mixture, and stirring and mixing to be uniform A solution-like acrylic pressure-sensitive adhesive composition B was prepared.

(Preparation of adhesive tape B)
Acrylic pressure-sensitive adhesive composition B is applied onto a release liner that has been subjected to a release treatment with silicone so that the thickness after drying is 30 μm, and dried in a hot air circulation oven at 100 ° C. for 3 minutes, Removed. Then, the adhesive tape B of the comparative example 2 was obtained by laminating the base material which consists of soft aluminum foil (80 micrometers) on the surface (adhesive surface) of the adhesive layer which consists of the dried acrylic adhesive composition B. .

[Evaluation 1]
(180 ° peel adhesion test)
From each of the pressure-sensitive adhesive tapes 10, 11, A, and B obtained in Examples 1 and 2 and Comparative Examples 1 and 2, two strip-shaped tape pieces (size: width 20 mm × length 100 mm) are each two (that is, Cut out in pairs). Next, the measurement surface (adhesive surface) of each one of the obtained strip-shaped tape pieces was affixed to an aluminum plate (width 50 mm × length 125 mm, thickness 2.0 mm) with the release liner peeled off, and 2 kg. The roller was pressed by reciprocating once. Thereafter, the sample was aged for 48 hours in an atmosphere of 23 ° C. and 50% RH to obtain a test sample. Using the test sample, a 180 ° peel test of the adhesive tape (strip-shaped tape piece) was performed, and the 180 ° peel adhesive strength (N / 20 mm) of the adhesive tape to the aluminum plate was measured. The measurement was performed under the conditions of a peeling angle of 180 ° and a tensile speed of 10 m / min using a tensile tester in an atmosphere of 23 ° C. and 50% RH. The measurement results (N / 20 mm) at a tensile speed of 10 m / min are shown in Table 1.

In addition, 180 degree adhesion of adhesive tape (strip-shaped tape piece) using the remaining strip-shaped tape pieces by the same method except changing the tension speed condition from 10 m / min to 30 m / min. The force was measured. The measurement results (N / 20 mm) at a tensile speed of 30 m / min are shown in Table 1.

[Evaluation 2]
(Adhesive residue determination)
In the aluminum plate after the 180 ° peel adhesion test described above, it was visually confirmed whether or not the adhesive remained at the place where the adhesive tape was affixed (so-called adhesive residue). The case where the adhesive remained to the extent that it could be visually confirmed remained on the aluminum plate was judged as “no adhesive residue”, and the case where it was not visually confirmed was judged as “no adhesive residue”. The adhesive residue determination was performed for each tensile speed condition. The determination results are shown in Table 1.

[Evaluation 3]
(Retention force test)
A strip-shaped tape piece (size: width 10 mm × length 100 mm) was cut out from each of the adhesive tapes 10, 11, A, and B obtained in Examples 1 and 2 and Comparative Examples 1 and 2. Next, the measurement surface (adhesive surface) of the strip-shaped tape piece is an aluminum plate (size: width 25 mm × length 125 mm, thickness 2 mm), and the application area is 200 mm ² (size: width 10 mm × length 20 mm). The release liner was stuck in a state where it was peeled off. Thereafter, a 2 kg roller was reciprocated once for pressure bonding and aged in an atmosphere of 60 ° C. and 50% RH for 0.5 hour to obtain a test sample. Using the test sample, the holding force of the adhesive tape (according to JIS-Z-0237) was measured. The evaluation of the holding force was performed when a tensile load of 9.8 N was applied to one end of the adhesive tape with the aluminum plate fixed in an atmosphere of 60 ° C. and 50% RH, with the aluminum plate fixed. Was measured by measuring the time until it peeled off from the aluminum plate.

When the adhesive tape was stuck to the aluminum plate for 20 minutes or more without being peeled off, the adhesive tape had sufficient holding power and was judged as “good”. On the other hand, when the time until the adhesive tape peeled off from the aluminum plate was less than 20 minutes, the holding force was insufficient and it was determined as “bad”. The results of the holding force test are shown in Table 1.

[Evaluation 4]
(Throwing force test)
For each of the adhesive tapes 10, 11, A, and B obtained in Examples 1 and 2 and Comparative Examples 1 and 2, the anchoring force (adhesive force of the adhesive layer to the base material) was evaluated by the test shown below. .

From the adhesive tapes 10, 1, A, and B obtained in Examples 1 and 2 and Comparative Examples 1 and 2, two strip-shaped tape pieces (size: width 10 mm × length 100 mm) were cut out. Subsequently, the cut out one tape piece is stacked on the other tape piece so that the adhesive layers are bonded together, and the stacked tape pieces are pressure-bonded by reciprocating a 2 kg roller, and then 23 ° C., A test sample was aged for 0.5 hour in an atmosphere of 50% RH. The anchoring force of the test sample was evaluated by peeling the test sample under the conditions of a peeling angle of 180 ° and a tensile speed of 180 m / min by the same method as the 180 ° peel adhesion test described above.

After the test sample is peeled off, if the adhesive layer of the adhesive tape (tape piece) is stuck without peeling off from the substrate, the adhesive tape (tape piece) has sufficient anchoring force and is judged as “good”. did. On the other hand, when the adhesive layer of the adhesive tape (tape piece) was peeled off from the base material after the test sample was peeled off, the anchoring force was insufficient and it was determined as “bad”. The results of the anchoring force test are shown in Table 1.

Each tensile speed (10 m / min, 30 m / min) of the adhesive tape in the 180 ° peel adhesive test corresponds to the speed at which a person peels the adhesive tape from the adherend by hand. The pressure-sensitive adhesive tape 10 of Example 1 includes a rubber-based pressure-sensitive adhesive layer 20 made of the rubber-based pressure-sensitive adhesive composition I. As shown in Table 1, no adhesive remains on the aluminum plate even if the adhesive tape 10 of Example 1 is affixed to the aluminum plate and then peeled off at any tensile speed condition after 48 hours. Was confirmed. Moreover, it was confirmed that the adhesive tape 10 of Example 1 was provided with sufficient holding power as a masking application.

Further, as shown in Table 1, the adhesive tape 11 of Example 2 was also attached to the aluminum plate as in Example 1, and even if it was peeled off at any tensile speed condition after 48 hours, the aluminum plate It was confirmed that no adhesive remained on the top. Moreover, it was confirmed that the adhesive tape 11 of Example 2 was provided with sufficient holding power as a masking application.

On the other hand, the pressure-sensitive adhesive tape A of Comparative Example 1 in which the pressure-sensitive adhesive layer is made of the acrylic pressure-sensitive adhesive composition A has sufficient holding power as a masking application, but the peel pressure-sensitive adhesive force under any tensile speed condition. After the test, it was confirmed that the adhesive remained on the aluminum plate. This is because the adhesiveness (initial adhesiveness) of the adhesive tape A to the adherend is too high, and the cohesive force of the adhesive layer is insufficient, so that when the adhesive tape A of Comparative Example 1 is peeled off, the adhesive It is considered that a part of the pressure-sensitive adhesive layer remained on the aluminum plate side due to the interlayer breakdown. It was confirmed that the adhesive remained on the aluminum plate in the form of scattered adhesives under any tensile speed conditions.

Moreover, when the adhesive tape B of the comparative example 2 which an adhesive layer consists of acrylic adhesive composition B was peeled off by low speed conditions (tensile speed of 10 m / min) in the said peel adhesive force test, Example 1 is shown. As with, no adhesive residue was found on the aluminum plate. However, in the peel adhesive strength test, it was confirmed that the adhesive remained on the aluminum plate when the adhesive tape B of Comparative Example 2 was peeled off under high speed conditions (tensile speed of 30 m / min). In the pressure-sensitive adhesive tape B of Comparative Example 2, it is considered that when peeled off under high speed conditions (tensile speed of 30 m / min), the pressure-sensitive adhesive layer was destroyed and a part of the pressure-sensitive adhesive layer remained on the aluminum plate side. The pressure-sensitive adhesive tape B of Comparative Example 2 has a smaller peel adhesive value than the pressure-sensitive adhesive tape A of Comparative Example 1, and has a value comparable to that of the pressure-sensitive adhesive tape 10 of Example 1. Nevertheless, in the adhesive tape B of Comparative Example 2, when the peeling is performed under a high speed condition (tensile speed of 30 m / min), adhesive residue is generated. This suggests that good peelability cannot be obtained only by suppressing the value of the peel adhesive strength. In addition, the adhesive tape B of the comparative example 2 was provided with sufficient holding force similarly to the adhesive tape 10 of Example 1.

When the adhesive tape is fixed to the adherend while holding other members, as in masking applications, the adhesive tape must have a sufficient holding force that does not peel off from the adherend. Is required. In an adhesive tape, it is very difficult to achieve both sufficient holding power and good peelability that does not cause adhesive residue on the adherend. For example, even if the 180 ° peel adhesive force is controlled, it is not possible to obtain an adhesive tape having both good peelability and holding power. However, in the pressure-sensitive adhesive tape 10 of Example 1, by using a predetermined rubber-based pressure-sensitive adhesive layer as the pressure-sensitive adhesive layer and using a metal foil as the base material, sufficient holding power and good peelability for masking applications can be obtained. It was confirmed that

In addition, the pressure-sensitive adhesive tape 11 of Example 2 uses a predetermined rubber-based pressure-sensitive adhesive layer similar to that of Example 1 as the pressure-sensitive adhesive layer, and uses a metal foil with an undercoat layer as a base material, thereby masking applications. It has been confirmed that it has both a sufficient holding power and good releasability while also having a throwing power (adhesive strength of the rubber-based pressure-sensitive adhesive layer to the base material). That is, the pressure-sensitive adhesive tape 11 of Example 2 can more reliably peel the rubber-based pressure-sensitive adhesive layer from the adherend without any adhesive residue.

10 ... Adhesive tape, 20 ... Rubber adhesive layer, 30 ... Base material (soft aluminum foil), 40 ... Release liner

Claims

A base material made of metal foil;
A rubber-based pressure-sensitive adhesive layer provided on one surface of the substrate;
The rubber-based pressure-sensitive adhesive layer is a pressure-sensitive adhesive tape containing 100 parts by weight of natural rubber and 10 to 110 parts by weight of synthetic rubber.
The pressure-sensitive adhesive tape according to claim 1, wherein the rubber-based pressure-sensitive adhesive layer contains a styrene-isoprene-styrene block copolymer as the synthetic rubber.
The pressure-sensitive adhesive tape according to claim 1 or 2, wherein the rubber-based pressure-sensitive adhesive layer contains a tackifier.
The pressure-sensitive adhesive tape according to any one of claims 1 to 3, wherein the metal foil is made of an aluminum foil.
The pressure-sensitive adhesive tape according to any one of claims 1 to 4, further comprising an undercoat layer between the base material and the rubber-based pressure-sensitive adhesive layer.
The pressure-sensitive adhesive tape according to any one of claims 1 to 5, which is for masking applied to an untreated portion of an adherend.