JP2019077880A - Double-sided adhesive tape - Google Patents

Double-sided adhesive tape Download PDF

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Publication number
JP2019077880A
JP2019077880A JP2019001871A JP2019001871A JP2019077880A JP 2019077880 A JP2019077880 A JP 2019077880A JP 2019001871 A JP2019001871 A JP 2019001871A JP 2019001871 A JP2019001871 A JP 2019001871A JP 2019077880 A JP2019077880 A JP 2019077880A
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pressure
sensitive adhesive
weight
meth
acrylic
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徳之 内田
Noriyuki Uchida
徳之 内田
勇樹 岩井
Yuki Iwai
勇樹 岩井
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Sekisui Chemical Co Ltd
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Sekisui Chemical Co Ltd
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B32B27/30—Layered products comprising a layer of synthetic resin comprising vinyl (co)polymers; comprising acrylic (co)polymers
    • B32B27/308—Layered products comprising a layer of synthetic resin comprising vinyl (co)polymers; comprising acrylic (co)polymers comprising acrylic (co)polymers
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J7/00—Adhesives in the form of films or foils
    • C09J7/20—Adhesives in the form of films or foils characterised by their carriers
    • C09J7/22—Plastics; Metallised plastics
    • C09J7/26—Porous or cellular plastics
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B32B27/06—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material
    • B32B27/065—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material of foam
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B7/00—Layered products characterised by the relation between layers; Layered products characterised by the relative orientation of features between layers, or by the relative values of a measurable parameter between layers, i.e. products comprising layers having different physical, chemical or physicochemical properties; Layered products characterised by the interconnection of layers
    • B32B7/04—Interconnection of layers
    • B32B7/12—Interconnection of layers using interposed adhesives or interposed materials with bonding properties
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J133/00—Adhesives based on homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides, or nitriles thereof; Adhesives based on derivatives of such polymers
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J133/00—Adhesives based on homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides, or nitriles thereof; Adhesives based on derivatives of such polymers
    • C09J133/04—Homopolymers or copolymers of esters
    • C09J133/06—Homopolymers or copolymers of esters of esters containing only carbon, hydrogen and oxygen, the oxygen atom being present only as part of the carboxyl radical
    • C09J133/08—Homopolymers or copolymers of acrylic acid esters
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J7/00—Adhesives in the form of films or foils
    • C09J7/30—Adhesives in the form of films or foils characterised by the adhesive composition
    • C09J7/38—Pressure-sensitive adhesives [PSA]
    • C09J7/381—Pressure-sensitive adhesives [PSA] based on macromolecular compounds obtained by reactions involving only carbon-to-carbon unsaturated bonds
    • C09J7/385—Acrylic polymers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2266/00—Composition of foam
    • B32B2266/02—Organic
    • B32B2266/0214—Materials belonging to B32B27/00
    • B32B2266/025—Polyolefin
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2307/00—Properties of the layers or laminate
    • B32B2307/70—Other properties
    • B32B2307/726—Permeability to liquids, absorption
    • B32B2307/7265—Non-permeable
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2405/00—Adhesive articles, e.g. adhesive tapes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2457/00—Electrical equipment
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F220/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride ester, amide, imide or nitrile thereof
    • C08F220/02—Monocarboxylic acids having less than ten carbon atoms; Derivatives thereof
    • C08F220/10—Esters
    • C08F220/12—Esters of monohydric alcohols or phenols
    • C08F220/16—Esters of monohydric alcohols or phenols of phenols or of alcohols containing two or more carbon atoms
    • C08F220/18—Esters of monohydric alcohols or phenols of phenols or of alcohols containing two or more carbon atoms with acrylic or methacrylic acids
    • C08F220/1804—C4-(meth)acrylate, e.g. butyl (meth)acrylate, isobutyl (meth)acrylate or tert-butyl (meth)acrylate
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J2203/00—Applications of adhesives in processes or use of adhesives in the form of films or foils
    • C09J2203/326—Applications of adhesives in processes or use of adhesives in the form of films or foils for bonding electronic components such as wafers, chips or semiconductors
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J2301/00—Additional features of adhesives in the form of films or foils
    • C09J2301/10—Additional features of adhesives in the form of films or foils characterized by the structural features of the adhesive tape or sheet
    • C09J2301/12—Additional features of adhesives in the form of films or foils characterized by the structural features of the adhesive tape or sheet by the arrangement of layers
    • C09J2301/124—Additional features of adhesives in the form of films or foils characterized by the structural features of the adhesive tape or sheet by the arrangement of layers the adhesive layer being present on both sides of the carrier, e.g. double-sided adhesive tape
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J2301/00—Additional features of adhesives in the form of films or foils
    • C09J2301/10—Additional features of adhesives in the form of films or foils characterized by the structural features of the adhesive tape or sheet
    • C09J2301/16—Additional features of adhesives in the form of films or foils characterized by the structural features of the adhesive tape or sheet by the structure of the carrier layer
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J2400/00—Presence of inorganic and organic materials
    • C09J2400/20—Presence of organic materials
    • C09J2400/24—Presence of a foam
    • C09J2400/243—Presence of a foam in the substrate
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J2423/00—Presence of polyolefin
    • C09J2423/006—Presence of polyolefin in the substrate

Landscapes

  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Adhesive Tapes (AREA)
  • Adhesives Or Adhesive Processes (AREA)
  • Laminated Bodies (AREA)

Abstract

To provide a double-sided adhesive tape which can achieve both high adhesiveness and high waterproofness at high levels.SOLUTION: In a double-sided adhesive tape related to this invention, when a pressure test is conducted in which a frame-shaped double-sided adhesive tape 1 including a predetermined foaming base material and first and second adhesive layers arranged at both sides of the foaming base material, and having a rectangular outer shape with a length of 61 mm and a width of 49 mm, a rectangular inner shape with a length of 57 mm and a width of 45 mm, and a width of 2 mm is prepared, a laminate 11 is obtained by laminating first and second acrylic sheets 2,3 on each other via the frame-shaped double-sided adhesive tape 1, air is introduced into an interior space 11A of the laminate 11 from a through hole 2a of the first acrylic sheet 2 of the laminate 11 so that an internal pressure of the interior space 11A gets to be 30 kPa, time passing before the internal pressure of the interior space 11A of the laminate 11 begins to decrease due to generation of peeling off on at least one interface between the frame-shaped double-sided adhesive tape 1 and the first and second acrylic sheets 2,3 is 50 min or more.SELECTED DRAWING: Figure 1

Description

本発明は、ポリオレフィン系樹脂により形成された発泡基材の両面に、粘着剤層が積層されている両面粘着テープに関する。   The present invention relates to a double-sided pressure-sensitive adhesive tape in which a pressure-sensitive adhesive layer is laminated on both sides of a foam substrate formed of a polyolefin resin.

携帯電話、及び携帯情報端末（Ｐｅｒｓｏｎａｌ Ｄｉｇｉｔａｌ Ａｓｓｉｓｔａｎｔｓ、ＰＤＡ）等の携帯電子機器は、例えば、使用者により意図せずに落下されることがある。落下による衝撃が付与されても、携帯電子機器の表示不良が生じないように、携帯電子機器には衝撃吸収性が求められている。   Mobile electronic devices such as mobile phones and personal digital assistants (PDAs) may be dropped by a user unintentionally, for example. A portable electronic device is required to have shock absorption so that display defects of the portable electronic device do not occur even if a shock is applied by a drop.

衝撃吸収性が高められた両面粘着テープが下記の特許文献１，２に開示されている。特許文献１，２に記載の両面粘着テープでは、基材層の少なくとも片面に（メタ）アクリル系粘着剤層が積層一体化されている。上記基材層は、特定の架橋度及び気泡のアスペクト比を有する架橋ポリオレフィン系樹脂発泡基材である。   The double-sided pressure-sensitive adhesive tapes with enhanced shock absorption are disclosed in Patent Documents 1 and 2 below. In the double-sided pressure-sensitive adhesive tape described in Patent Documents 1 and 2, a (meth) acrylic pressure-sensitive adhesive layer is integrally laminated on at least one surface of a base material layer. The base material layer is a crosslinked polyolefin resin foam base material having a specific degree of crosslinking and an aspect ratio of cells.

また、携帯電子機器は、意図せずに水中に落下されることがある。さらに、携帯電子機器には、雨などの水滴が付着することもある。携帯電子機器に水分が多く付着すると、携帯電子機器の内部に水分が侵入して、表示不良が生じることがある。このような水分に起因する表示不良が生じないように、携帯電子機器には、高い防水性が求められている。   Also, portable electronic devices may be dropped into water unintentionally. Furthermore, water droplets such as rain may adhere to portable electronic devices. When a large amount of water adheres to the portable electronic device, the water may intrude into the inside of the portable electronic device to cause display failure. In order to prevent display defects caused by such moisture, portable electronic devices are required to have high waterproofness.

また、携帯電子機器では、例えば、装置表面を構成するガラス板と画像表示部材との間に、これらを接着するために両面粘着テープが用いられている。この両面粘着テープにも、高い衝撃吸収性と高い防水性とが求められている。   In portable electronic devices, for example, a double-sided pressure-sensitive adhesive tape is used to bond them between a glass plate forming an apparatus surface and an image display member. This double-sided adhesive tape is also required to have high impact absorption and high waterproofness.

また更に、携帯電子機器の薄型化が進行している。薄型化に伴って、ポリカーボネートなどの表示パネル部品が温度変化によって反りやすくなっている。携帯電子機器が過酷な温度環境に晒されても、両面粘着テープが部品から剥離しないことも望まれている。   Furthermore, thinning of portable electronic devices is in progress. With thinning, display panel parts such as polycarbonate are easily warped due to temperature change. It is also desirable that the double-sided pressure-sensitive adhesive tape does not peel off from parts even when the portable electronic device is exposed to a severe temperature environment.

特開２００９−２４２５４１号公報JP, 2009-242541, A 特開２００９−２５８２７４号公報JP, 2009-258274, A

特許文献１，２に記載の両面粘着テープでは、衝撃吸収性にある程度優れている。しかし、特許文献１，２に記載のような従来の両面粘着テープにおいて、高い接着性と高い防水性との双方をより一層高いレベルで両立することが求められている。両面粘着テープにより接着された部品に反りが生じても、剥離が生じ難いことが求められている。また、両面粘着テープにより接着された電子機器等に水分が付着しても、両面粘着テープの接着界面から水分の浸入を抑えることが求められている。   The double-sided pressure-sensitive adhesive tapes described in Patent Documents 1 and 2 are excellent in shock absorption to some extent. However, in the conventional double-sided pressure-sensitive adhesive tapes as described in Patent Documents 1 and 2, it is required to achieve both high adhesion and high waterproofness at a still higher level. It is required that peeling does not easily occur even if warpage occurs in a component adhered by the double-sided pressure-sensitive adhesive tape. Moreover, even if water adheres to the electronic device etc. which were adhere | attached by the double-sided adhesive tape, suppressing permeation of water from the adhesion interface of a double-sided adhesive tape is calculated | required.

本発明の目的は、高い接着性と高い防水性との双方を高いレベルで両立することができる両面粘着テープを提供することである。   An object of the present invention is to provide a double-sided pressure-sensitive adhesive tape capable of achieving both high adhesion and high waterproofness at a high level.

本発明の広い局面によれば、ポリオレフィン系樹脂により形成されている発泡基材と、前記発泡基材の第１の表面側に配置されており、かつ、（メタ）アクリル系粘着剤により形成されている第１の粘着剤層と、上記発泡基材の上記第１の表面側とは反対の第２の表面側に配置されており、かつ、（メタ）アクリル系粘着剤により形成されている第２の粘着剤層とを備え、長さ６１ｍｍ及び幅４９ｍｍの矩形の外形を有し、長さ５７ｍｍ及び幅４５ｍｍの矩形の内形を有し、かつ２ｍｍの幅を有する枠状の両面粘着テープを用意し、長さ１００ｍｍ、幅１００ｍｍ及び厚み１０ｍｍの矩形を有し、かつ貫通孔を有する第１のアクリル板を用意し、長さ１００ｍｍ、幅１００ｍｍ及び厚み１０ｍｍの矩形を有し、かつ貫通孔を有さない第２のアクリル板を用意して、上記第１のアクリル板と上記第２のアクリル板とを上記枠状の両面粘着テープを介して貼り合わせて、上記第１のアクリル板と上記第２のアクリル板と上記枠状の両面粘着テープとで囲まれた内部空間を有する積層体を得て、上記積層体における上記第１のアクリル板の貫通孔から上記積層体の上記内部空間に空気を入れ、上記内部空間の内圧を３０ｋＰａにする加圧試験を行ったときに、上記枠状の両面粘着テープと上記第１のアクリル板及び上記第２のアクリル板との少なくとも一方の界面で剥離が生じることによって、上記積層体の上記内部空間の内圧が減少し始めるまでの時間が５０分以上である、両面粘着テープが提供される。   According to a broad aspect of the present invention, a foamed substrate formed of a polyolefin-based resin, and a first surface side of the foamed substrate, which is formed of a (meth) acrylic pressure-sensitive adhesive The first adhesive layer is disposed, and the second surface side opposite to the first surface side of the foam substrate is disposed, and is formed of a (meth) acrylic adhesive A frame-shaped double-sided adhesive having a rectangular outer shape 61 mm long and 49 mm wide, having a rectangular inner shape 57 mm long and 45 mm wide, and having a second adhesive layer A first acrylic plate is prepared which has a tape 100 mm in length, 100 mm in width and 10 mm in thickness and has a through hole, and has a rectangle of 100 mm in length, 100 mm in width and 10 mm in thickness, and Second air having no through hole A llyl plate is prepared, and the first acrylic plate and the second acrylic plate are pasted together via the frame-shaped double-sided adhesive tape to form the first acrylic plate and the second acrylic plate. A laminate having an internal space surrounded by the frame-shaped double-sided adhesive tape is obtained, and air is introduced into the internal space of the laminate from the through hole of the first acrylic plate in the laminate; When a pressure test is performed to set the internal pressure of the space to 30 kPa, peeling occurs at the interface between at least one of the frame-shaped double-sided adhesive tape and the first acrylic plate and the second acrylic plate. A double-sided pressure-sensitive adhesive tape is provided, which has a time of 50 minutes or more until the internal pressure of the internal space of the laminate starts to decrease.

本発明に係る両面粘着テープのある特定の局面では、上記第１の粘着剤層に含まれる上記（メタ）アクリル系粘着剤が、（メタ）アクリル重合体と粘着付与樹脂を含み、上記第１の粘着剤層において、上記（メタ）アクリル重合体１００重量部に対する上記粘着付与樹脂の含有量が３６重量部以上、５０重量部以下であり、上記第２の粘着剤層に含まれる上記（メタ）アクリル系粘着剤が、（メタ）アクリル重合体と粘着付与樹脂を含み、上記第２の粘着剤層において、上記（メタ）アクリル重合体１００重量部に対する上記粘着付与樹脂の含有量が３６重量部以上、５０重量部以下である。   In a specific aspect of the double-sided pressure-sensitive adhesive tape according to the present invention, the (meth) acrylic pressure-sensitive adhesive contained in the first pressure-sensitive adhesive layer contains a (meth) acrylic polymer and a tackifier resin; In the pressure-sensitive adhesive layer, the content of the tackifying resin relative to 100 parts by weight of the (meth) acrylic polymer is 36 parts by weight or more and 50 parts by weight or less, and the above-mentioned (meth) The acrylic pressure-sensitive adhesive contains a (meth) acrylic polymer and a tackifier resin, and in the second pressure-sensitive adhesive layer, the content of the tackifier resin relative to 100 parts by weight of the (meth) acrylic polymer is 36 weight More than 50 parts by weight.

本発明に係る両面粘着テープのある特定の局面では、上記第１の粘着剤層に含まれる上記（メタ）アクリル系粘着剤が、重量平均分子量の数平均分子量に対する比が１０以上、１５以下である（メタ）アクリル重合体を含み、上記第２の粘着剤層に含まれる上記（メタ）アクリル系粘着剤が、重量平均分子量の数平均分子量に対する比が１０以上、１５以下である（メタ）アクリル重合体を含む。   In a specific aspect of the double-sided pressure-sensitive adhesive tape according to the present invention, the (meth) acrylic pressure-sensitive adhesive contained in the first pressure-sensitive adhesive layer has a weight average molecular weight to number average molecular weight ratio of 10 or more and 15 or less The ratio of the weight average molecular weight to the number average molecular weight of the (meth) acrylic pressure-sensitive adhesive which contains a certain (meth) acrylic polymer and is contained in the second pressure-sensitive adhesive layer is 10 or more and 15 or less (meth) It contains an acrylic polymer.

本発明に係る両面粘着テープのある特定の局面では、上記第１の粘着剤層に含まれる上記（メタ）アクリル系粘着剤が、（メタ）アクリル重合体と粘着付与樹脂を含み、上記第１の粘着剤層において、上記（メタ）アクリル重合体１００重量部に対する上記粘着付与樹脂の含有量が４０重量部以上、５０重量部以下であり、上記第２の粘着剤層に含まれる上記（メタ）アクリル系粘着剤が、（メタ）アクリル重合体と粘着付与樹脂を含み、上記第２の粘着剤層において、上記（メタ）アクリル重合体１００重量部に対する上記粘着付与樹脂の含有量が４０重量部以上、５０重量部以下である。   In a specific aspect of the double-sided pressure-sensitive adhesive tape according to the present invention, the (meth) acrylic pressure-sensitive adhesive contained in the first pressure-sensitive adhesive layer contains a (meth) acrylic polymer and a tackifier resin; In the pressure-sensitive adhesive layer, the content of the tackifying resin is 40 parts by weight or more and 50 parts by weight or less based on 100 parts by weight of the (meth) acrylic polymer, and the above-mentioned (meth) ) The acrylic pressure-sensitive adhesive contains a (meth) acrylic polymer and a tackifying resin, and in the second pressure-sensitive adhesive layer, the content of the tackifying resin relative to 100 parts by weight of the (meth) acrylic polymer is 40 weight More than 50 parts by weight.

本発明に係る両面粘着テープのある特定の局面では、上記第１の粘着剤層のゲル分率が１５重量％以上、５０重量％以下であり、上記第２の粘着剤層のゲル分率が１５重量％以上、５０重量％以下である。   In a specific aspect of the double-sided pressure-sensitive adhesive tape according to the present invention, the gel fraction of the first pressure-sensitive adhesive layer is 15% by weight or more and 50% by weight or less, and the gel fraction of the second pressure-sensitive adhesive layer is 15% by weight or more and 50% by weight or less.

本発明に係る両面粘着テープのある特定の局面では、上記発泡基材が、上記ポリオレフィン系樹脂を架橋及び発泡させることにより得られる。   In a specific aspect of the double-sided pressure-sensitive adhesive tape according to the present invention, the foam base is obtained by crosslinking and foaming the polyolefin resin.

本発明に係る両面粘着テープのある特定の局面では、上記第１の粘着剤層の厚みが２５μｍ以上、１００μｍ以下であり、上記第２の粘着剤層の厚みが２５μｍ以上、１００μｍ以下である。   In a specific aspect of the double-sided pressure-sensitive adhesive tape according to the present invention, the thickness of the first pressure-sensitive adhesive layer is 25 μm to 100 μm, and the thickness of the second pressure-sensitive adhesive layer is 25 μm to 100 μm.

本発明に係る両面粘着テープは、ポリオレフィン系樹脂により形成されている発泡基材と、上記発泡基材の第１の表面側に配置されており、かつ、（メタ）アクリル系粘着剤により形成されている第１の粘着剤層と、上記発泡基材の上記第１の表面側とは反対の第２の表面側に配置されており、かつ、（メタ）アクリル系粘着剤により形成されている第２の粘着剤層とを備えており、長さ６１ｍｍ及び幅４９ｍｍの矩形の外形を有し、長さ５７ｍｍ及び幅４５ｍｍの矩形の内形を有し、かつ２ｍｍの幅を有する枠状の両面粘着テープを介して、第１，第２のアクリル板を貼り合わせた積層体を用いて加圧試験を行ったときに、上記枠状の両面粘着テープと上記第１，第２のアクリル板との少なくとも一方の界面で剥離が生じることによって、上記積層体の上記内部空間の内圧が減少し始めるまでの時間が５０分以上であるので、高い接着性と高い防水性との双方を高いレベルで両立することができる。   The double-sided pressure-sensitive adhesive tape according to the present invention comprises a foam base formed of a polyolefin resin, and a first surface side of the foam base and is formed of a (meth) acrylic pressure-sensitive adhesive The first adhesive layer is disposed, and the second surface side opposite to the first surface side of the foam substrate is disposed, and is formed of a (meth) acrylic adhesive A second adhesive layer, having a rectangular outer shape of 61 mm in length and 49 mm in width, and having a rectangular inner shape of 57 mm in length and 45 mm in width and having a width of 2 mm The frame-shaped double-sided adhesive tape and the first and second acrylic plates described above are subjected to a pressure test using a laminate obtained by bonding the first and second acrylic plates together via the double-sided adhesive tape. Exfoliation at at least one of the interfaces with Since the time until the internal pressure of the internal space of the serial laminate begins to decrease is not less than 50 minutes, it is possible to achieve both both high adhesion and high waterproofness at a high level.

図１（ａ）及び（ｂ）は、加圧試験の方法を説明するための模式的な正面断面図及び平面断面図である。Fig.1 (a) and (b) are typical front sectional drawing and plane sectional drawing for demonstrating the method of a pressurization test. 図２は、耐反発性試験の方法を説明するための模式的な斜視図である。FIG. 2 is a schematic perspective view for explaining the method of the repulsion resistance test.

以下、本発明を詳細に説明する。   Hereinafter, the present invention will be described in detail.

（両面粘着テープ）
本発明に係る両面粘着テープは、発泡基材と、第１の粘着剤層と、第２の粘着剤層とを備える。上記第１の粘着剤層は、上記発泡基材の第１の表面側に配置されている。上記第２の粘着剤層は、上記発泡基材の上記第１の表面側とは反対の第２の表面側に配置されている。上記発泡基材は、上記第１の粘着剤層と上記第２の粘着剤層との間に配置されている。上記発泡基材は、発泡体であり、基材層である。上記発泡基材は、ポリオレフィン系樹脂により形成されている。上記第１の粘着剤層は、（メタ）アクリル系粘着剤により形成されている。上記第２の粘着剤層は、（メタ）アクリル系粘着剤により形成されている。 (Double-sided adhesive tape)
The double-sided pressure-sensitive adhesive tape according to the present invention comprises a foam base, a first pressure-sensitive adhesive layer, and a second pressure-sensitive adhesive layer. The first pressure-sensitive adhesive layer is disposed on the first surface side of the foam substrate. The second pressure-sensitive adhesive layer is disposed on a second surface side opposite to the first surface side of the foam substrate. The foam substrate is disposed between the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer. The foam substrate is a foam and is a substrate layer. The foam base is formed of a polyolefin resin. The first pressure-sensitive adhesive layer is formed of a (meth) acrylic pressure-sensitive adhesive. The second pressure-sensitive adhesive layer is formed of a (meth) acrylic pressure-sensitive adhesive.

本発明に係る両面粘着テープでは、以下の所定の加圧試験を行った時に、かなり良好な性質を示す。   The double-sided pressure-sensitive adhesive tape according to the present invention exhibits quite good properties when subjected to the following predetermined pressure test.

［加圧試験の詳細］
図１を参照しつつ、加圧試験の詳細を説明する。図１（ａ）は、加圧試験時の状態を模式的に示す正面断面図である。図１（ｂ）は、図１（ａ）のＩ−Ｉ線に沿う平面断面図である。 [Details of pressure test]
The details of the pressure test will be described with reference to FIG. FIG. 1 (a) is a front cross-sectional view schematically showing the state in the pressure test. FIG.1 (b) is a plane sectional view in alignment with the II line of Fig.1 (a).

本発明に係る両面粘着テープを用いて、長さ６１ｍｍ及び幅４９ｍｍの矩形の外形を有し、長さ５７ｍｍ及び幅４５ｍｍの矩形の内形を有し、かつ２ｍｍの幅を有する枠状の両面粘着テープ１を用意する。   The double-sided pressure-sensitive adhesive tape according to the present invention has a rectangular outer shape 61 mm long and 49 mm wide, has a rectangular inner shape 57 mm long and 45 mm wide, and has a frame-like double-sided width 2 mm Prepare an adhesive tape 1.

本発明に係る両面粘着テープが長さ６１ｍｍ及び幅４９ｍｍの矩形の外形を有し、長さ５７ｍｍ及び幅４５ｍｍの矩形の内形を有し、かつ２ｍｍの幅を有する枠状の両面粘着テープ１である場合には、該両面粘着テープをそのまま用いる。本発明に係る両面粘着テープがこのような形状ではない場合には、このような形状に切断する。なお、加圧試験に用いる枠状の両面粘着テープ１の厚みは、本発明に係る両面粘着テープ自体の厚みである。   The double-sided pressure-sensitive adhesive tape according to the present invention has a rectangular outer shape with a length of 61 mm and a width of 49 mm, a rectangular inner shape with a length of 57 mm and a width of 45 mm, and a frame-like double-sided pressure-sensitive adhesive tape 1 with a width of 2 mm If so, the double-sided pressure-sensitive adhesive tape is used as it is. When the double-sided pressure-sensitive adhesive tape according to the present invention does not have such a shape, it is cut into such a shape. In addition, the thickness of the frame-shaped double-sided adhesive tape 1 used for a pressure test is the thickness of the double-sided adhesive tape itself which concerns on this invention.

また、長さ１００ｍｍ、幅１００ｍｍ及び厚み１０ｍｍの矩形を有し、かつ貫通孔２ａを有する第１のアクリル板２を用意する。貫通孔２ａは、直径１ｃｍの円形であることが好ましい。貫通孔２ａは、好ましくは第１のアクリル板２の中心部に設けられる。さらに、長さ１００ｍｍ、幅１００ｍｍ及び厚み１０ｍｍの矩形を有し、かつ貫通孔を有さない第２のアクリル板３を用意する。   In addition, a first acrylic plate 2 having a rectangle of 100 mm in length, 100 mm in width and 10 mm in thickness and having a through hole 2 a is prepared. The through holes 2a are preferably circular with a diameter of 1 cm. The through hole 2 a is preferably provided at the center of the first acrylic plate 2. Furthermore, the 2nd acrylic board 3 which has a rectangle of length 100 mm, width 100 mm, and thickness 10 mm and does not have a through-hole is prepared.

第１のアクリル板２と第２のアクリル板３とを枠状の両面粘着テープ１を介して貼り合わせて、第１のアクリル板２と第２のアクリル板３と枠状の両面粘着テープ１とで囲まれた内部空間１１Ａを有する積層体１１を得る。この積層体１１を用いて、加圧試験が行われる。具体的には、積層体１１における第１のアクリル板２の貫通孔２ａから積層体１１の内部空間１１Ａに空気を入れ、内部空間１１Ａの内圧を３０ｋＰａにする加圧試験を行う。加圧試験時には、枠状の両面粘着テープ１と第１のアクリル板２との接着界面、並びに枠状の両面粘着テープ１と第２のアクリル板３との接着界面は水中に配置されることが好ましい。この場合には、接着界面からの空気漏れを容易に把握することができる。   The first acrylic plate 2 and the second acrylic plate 3 are pasted together via the frame-shaped double-sided adhesive tape 1, and the first acrylic plate 2 and the second acrylic plate 3 and the frame-shaped double-sided adhesive tape 1 A stack 11 is obtained having an inner space 11A surrounded by and. A pressure test is performed using this laminate 11. Specifically, air is introduced from the through holes 2a of the first acrylic plate 2 in the laminate 11 into the internal space 11A of the laminate 11, and a pressure test is performed to set the internal pressure of the internal space 11A to 30 kPa. During the pressure test, the adhesive interface between the frame-shaped double-sided adhesive tape 1 and the first acrylic plate 2 and the adhesive interface between the frame-shaped double-sided adhesive tape 1 and the second acrylic plate 3 are placed in water. Is preferred. In this case, air leakage from the adhesive interface can be easily grasped.

本発明では、上記加圧試験において、枠状の両面粘着テープ１と第１のアクリル板２及び第２のアクリル板３との少なくとも一方の界面で剥離が生じることによって、積層体１１の内部空間１１Ａの内圧が減少し始めるまでの時間（内圧減少開始時間）が５０分以上である。枠状の両面粘着テープ１と第１のアクリル板２及び第２のアクリル板３との少なくとも一方の界面で剥離が生じることによって、積層体１１の内部空間１１Ａの内圧が減少しているか否かは、積層体１１を水中に配置し、上記枠状の両面粘着テープ１と第１のアクリル板２及び第２のアクリル板３との少なくとも一方の界面からの空気が漏れているか否かを観測することにより、判断される。   In the present invention, in the pressure test described above, peeling occurs at the interface between at least one of the frame-shaped double-sided pressure-sensitive adhesive tape 1 and the first acrylic plate 2 and the second acrylic plate 3 to form the internal space of the laminate 11. The time until the internal pressure of 11A starts to decrease (internal pressure decrease start time) is 50 minutes or more. Whether the internal pressure of the internal space 11A of the laminate 11 is decreased by peeling at the interface between at least one of the frame-shaped double-sided adhesive tape 1 and the first acrylic plate 2 and the second acrylic plate 3 , Place the laminate 11 in water, and observe whether air leaks from the interface between at least one of the frame-shaped double-sided pressure-sensitive adhesive tape 1 and the first acrylic plate 2 and the second acrylic plate 3 It is judged by doing.

防水性及び接着性をより一層高める観点からは、上記内圧減少開始時間は長いほどよい。上記内圧減少開始時間は、好ましくは５５分以上、より好ましくは６０分以上、更に好ましくは６５分以上、特に好ましくは７０分以上、最も好ましくは８０分以上である。   From the viewpoint of further enhancing the waterproofness and adhesion, the longer the internal pressure decrease start time, the better. The internal pressure decrease start time is preferably 55 minutes or more, more preferably 60 minutes or more, still more preferably 65 minutes or more, particularly preferably 70 minutes or more, and most preferably 80 minutes or more.

以下、本発明に係る両面粘着テープの他の詳細を説明する。   Hereinafter, other details of the double-sided pressure-sensitive adhesive tape according to the present invention will be described.

［発泡基材の詳細］
衝撃吸収性をより一層高める観点からは、上記発泡基材は、ポリオレフィン系樹脂を架橋及び発泡させることにより得られることが好ましい。上記発泡基材は、架橋ポリオレフィン系樹脂発泡体であることが好ましい。上記発泡基材は内部に複数の気泡を有する。 [Details of foam base material]
From the viewpoint of further enhancing impact absorption, the foam base is preferably obtained by crosslinking and foaming a polyolefin resin. The foam substrate is preferably a crosslinked polyolefin resin foam. The foam substrate has a plurality of cells inside.

上記発泡基材における発泡倍率は好ましくは１．５倍以上、より好ましくは２倍以上、好ましくは１０倍以下、より好ましくは８倍以下である。上記発泡倍率が上記下限以上であると、発泡基材の柔軟性がより一層高くなり、発泡基材の衝撃吸収性がより一層高くなり、衝撃が付与されても剥離が生じ難くなる。上記発泡倍率が上記上限以下であると、発泡基材の強度がより一層高くなり、発泡基材に衝撃が付与されても、発泡基材が破損し難くなる。   The expansion ratio of the foam base is preferably 1.5 times or more, more preferably 2 times or more, preferably 10 times or less, more preferably 8 times or less. The softness | flexibility of a foaming base material becomes it still higher that the said foaming ratio is more than the said minimum, the impact-absorbing property of a foaming base material becomes still higher, and peeling becomes difficult to occur even if an impact is provided. When the expansion ratio is equal to or less than the upper limit, the strength of the foam substrate is further enhanced, and even if an impact is applied to the foam substrate, the foam substrate is less likely to be broken.

上記発泡倍率は、ＪＩＳ Ｋ６７６７に準拠して、電子比重計（ミラージュ社製「ＥＤ１２０Ｔ」）を用いて、見かけ密度を測定した後、見かけ密度の逆数を求めることで算出される。   The expansion ratio is calculated by measuring the apparent density using an electronic densimeter ("ED120T" manufactured by Mirage) in accordance with JIS K6767, and then calculating the reciprocal of the apparent density.

上記発泡基材の厚み方向の２５％圧縮強度は、好ましくは１０ｋＰａ以上、より好ましくは２５０ｋＰａ以上、更に好ましくは３００ｋＰａ以上、好ましくは１０００ｋＰａ以下、より好ましくは５００ｋＰａ以下、更に好ましくは４００ｋＰａ以下である。２５％圧縮強度が上記下限以上であると、発泡基材の強度がより一層高くなり、発泡基材に衝撃が付与されても、発泡基材が破損し難くなる。２５％圧縮強度が上記上限以下であると、発泡基材の柔軟性がより一層高くなり、発泡基材の衝撃吸収性がより一層高くなり、衝撃が付与されても剥離が生じ難くなる。   The 25% compressive strength of the foamed base in the thickness direction is preferably 10 kPa or more, more preferably 250 kPa or more, still more preferably 300 kPa or more, preferably 1000 kPa or less, more preferably 500 kPa or less, still more preferably 400 kPa or less. When the 25% compressive strength is at least the above lower limit, the strength of the foam substrate is further enhanced, and even if an impact is applied to the foam substrate, the foam substrate is less likely to be broken. When the 25% compressive strength is less than or equal to the above upper limit, the flexibility of the foam substrate is further enhanced, the impact absorption of the foam substrate is further enhanced, and peeling is less likely to occur even when an impact is applied.

厚み方向の２５％圧縮強度は、ＪＩＳ Ｋ６７６７に準拠して測定される。例えば、２０ｍｍ×２０ｍｍに裁断した発泡基材を重ね合わせて、厚み１０ｍｍの積層体を作製する。この積層体を２３℃下に放置した後、２３℃にて、積層体の厚み方向の２５％圧縮強度を測定する。   The 25% compressive strength in the thickness direction is measured in accordance with JIS K6767. For example, the foam base material cut | judged to 20 mm x 20 mm is piled up, and the 10-mm-thick laminated body is produced. After the laminate is left at 23 ° C., the 25% compressive strength in the thickness direction of the laminate is measured at 23 ° C.

上記発泡基材の厚みは特に限定されない。上記発泡基材の厚みは好ましくは０．０２ｍｍ以上、より好ましくは０．０３ｍｍ以上、更に好ましくは０．０５ｍｍ以上、好ましくは１．２ｍｍ以下、より好ましくは１．０ｍｍ以下、更に好ましくは０．５ｍｍ以下である。上記厚みが上記下限以上であると、発泡基材の強度がより一層高くなり、発泡基材に衝撃が付与されても、発泡基材が破損し難くなる。上記厚みが上記上限以下であると、発泡基材の柔軟性がより一層高くなり、発泡基材の衝撃吸収性がより一層高くなり、衝撃が付与されても剥離が生じ難くなり、更に被着体の形状に追従して貼り合わせることがより一層容易になる。また、上記厚みが上記上限以下であると、電子機器等の小型化及び薄型化に対応できる。   The thickness of the foam substrate is not particularly limited. The thickness of the foam substrate is preferably 0.02 mm or more, more preferably 0.03 mm or more, still more preferably 0.05 mm or more, preferably 1.2 mm or less, more preferably 1.0 mm or less, still more preferably 0. It is 5 mm or less. The intensity | strength of a foaming base material will become still higher as the said thickness is more than the said minimum, and even if an impact is provided to a foaming base material, a foaming base material becomes difficult to be damaged. The softness | flexibility of a foaming base material becomes it still higher that the said thickness is below the said upper limit, the impact-absorbing property of a foaming base material becomes still higher, peeling becomes difficult to occur even if an impact is given, and also adhesion is carried out. It becomes easier to follow and stick to the shape of the body. Moreover, it can respond to size reduction and thickness reduction of an electronic device etc. as the said thickness is below the said upper limit.

＜ポリオレフィン系樹脂＞
上記発泡基材を形成するために用いられるポリオレフィン系樹脂としては、特に限定されないが、エチレン単独重合体、エチレン−α−オレフィン共重合体、エチレン−（メタ）アクリル酸共重合体、エチレン−（メタ）アクリル酸エステル共重合体、及びエチレン−酢酸ビニル共重合体などのポリエチレン系樹脂；プロピレン単独重合体、プロピレン−α−オレフィン共重合体、及びプロピレン−エチレン共重合体などのポリプロピレン系樹脂；ブテン単独重合体；ブタジエン及びイソプレンなどの共役ジエンの単独重合体又は共重合体等が挙げられる。また、上記ポリエチレン系樹脂としては、高密度ポリエチレン及び低密度ポリエチレン等が挙げられる。共重合の形態は、ランダムであってもよく、ブロックであってもよく、三元共重合体の形態であってもよい。 <Polyolefin resin>
Although it does not specifically limit as polyolefin resin used in order to form the said foaming base material, An ethylene homopolymer, an ethylene-alpha-olefin copolymer, an ethylene- (meth) acrylic acid copolymer, ethylene- ( Polyethylene based resins such as meta) acrylic acid ester copolymer and ethylene-vinyl acetate copolymer; Polypropylene based resins such as propylene homopolymer, propylene-α-olefin copolymer, and propylene-ethylene copolymer Examples thereof include butene homopolymers; homopolymers or copolymers of conjugated dienes such as butadiene and isoprene. Moreover, high density polyethylene, low density polyethylene, etc. are mentioned as said polyethylene-type resin. The form of the copolymerization may be random, may be a block, or may be in the form of a terpolymer.

上記ポリオレフィン系樹脂は、ポリエチレン系樹脂又はポリプロピレン系樹脂であってもよく、ポリエチレン系樹脂であってもよく、ポリプロピレン系樹脂であってもよい。ポリエチレン系樹脂とポリプロピレン系樹脂とを混合して用いてもよい。   The polyolefin resin may be a polyethylene resin or a polypropylene resin, may be a polyethylene resin, or may be a polypropylene resin. A polyethylene resin and a polypropylene resin may be mixed and used.

上記ポリエチレン系樹脂は、エチレンを主成分として用いて得られる。上記ポリエチレン系樹脂の全構造単位１００重量％中、エチレンに由来する構造単位の割合は好ましくは５０重量％以上、より好ましくは７０重量％以上、更に好ましくは９０重量％以上である。   The said polyethylene-type resin is obtained using ethylene as a main component. The proportion of structural units derived from ethylene is preferably 50% by weight or more, more preferably 70% by weight or more, and still more preferably 90% by weight or more in 100% by weight of the total structural units of the polyethylene resin.

上記ポリプロピレン系樹脂は、プロピレンを主成分として用いて得られる。上記ポリプロピレン系樹脂の全構造単位１００重量％中、プロピレンに由来する構造単位の割合は好ましくは５０重量％以上、より好ましくは７０重量％以上、更に好ましくは９０重量％以上である。   The said polypropylene resin is obtained using propylene as a main component. The proportion of structural units derived from propylene is preferably 50% by weight or more, more preferably 70% by weight or more, and still more preferably 90% by weight or more in 100% by weight of the total structural units of the polypropylene resin.

衝撃吸収性をより一層高める観点から、上記ポリオレフィン系樹脂は、好ましくはポリエチレン系樹脂であり、より好ましくは低密度ポリエチレンであり、更に好ましくは直鎖状低密度ポリエチレンである。また、上記ポリエチレン系樹脂は、エチレン単独重合体でもよいが、上記ポリエチレン系樹脂は、全構造単位１００重量％中、エチレンに由来する構造単位を好ましくは７０重量％以上、より好ましくは９０重量％以上有し、α−オレフィン構造単位を好ましくは３０重量％以下、より好ましくは１０重量％以下有するポリエチレン系樹脂であることが好ましい。   From the viewpoint of further enhancing impact absorption, the above-mentioned polyolefin resin is preferably a polyethylene resin, more preferably low density polyethylene, and still more preferably linear low density polyethylene. The polyethylene-based resin may be ethylene homopolymer, but the polyethylene-based resin preferably contains 70% by weight or more, more preferably 90% by weight of structural units derived from ethylene in 100% by weight of all structural units. It is preferable that it is the polyethylene-type resin which it has above and has an alpha-olefin structural unit preferably 30 weight% or less, more preferably 10 weight% or less.

また、メタロセン化合物の重合触媒を用いて得られたポリエチレン系樹脂を用いることにより、特にメタロセン化合物の重合触媒を用いて得られた直鎖状低密度ポリエチレンを用いることにより、柔軟性が高くかつ衝撃吸収性が高い発泡基材が得やすくなる。また、発泡基材の厚みを薄くしても、高い性能を維持しやすくなる。   In addition, by using a polyethylene resin obtained by using a polymerization catalyst of a metallocene compound, particularly by using a linear low density polyethylene obtained by using a polymerization catalyst of a metallocene compound, the flexibility is high and the impact is high. It becomes easy to obtain a foam base material with high absorbency. In addition, even if the thickness of the foam substrate is reduced, high performance can be easily maintained.

見かけ密度、及び、厚み方向の２５％圧縮強度を上記範囲に調整するためには、上記ポリオレフィン系樹脂は、重合触媒として四価の遷移金属を含むメタロセン化合物を用いて得られるポリオレフィン系樹脂（メタロセン系ポリオレフィン系樹脂）であることが好ましい。なかでも、メタロセン化合物を用いて得られたポリエチレン系樹脂（メタロセン系ポリエチレン系樹脂）が好ましい。上記メタロセン化合物としては、例えば、カミンスキー触媒等が挙げられる。   In order to adjust the apparent density and the 25% compressive strength in the thickness direction to the above range, the above-mentioned polyolefin resin is a polyolefin resin obtained by using a metallocene compound containing a tetravalent transition metal as a polymerization catalyst (metallocene It is preferable that it is a system polyolefin resin. Among them, a polyethylene-based resin (metallocene-based polyethylene-based resin) obtained using a metallocene compound is preferable. As said metallocene compound, a Kamin ski catalyst etc. are mentioned, for example.

上記メタロセン系ポリエチレン系樹脂としては、例えば、上記メタロセン化合物を用いて、エチレンと、必要に応じて配合される他のα−オレフィンとを共重合することにより得られたポリエチレン系樹脂等が挙げられる。上記他のα−オレフィンとして、例えば、プロペン、１−ブテン、１−ペンテン、及び１−ヘキセン等が挙げられる。   Examples of the metallocene-based polyethylene-based resin include polyethylene-based resins obtained by copolymerizing ethylene and other α-olefins optionally blended, using the above-mentioned metallocene compound. . Examples of the other α-olefins include propene, 1-butene, 1-pentene, and 1-hexene.

上記ポリオレフィン系樹脂は、上記メタロセン系ポリエチレン系樹脂に加えて、更に、他のオレフィン系樹脂を含んでいてもよい。上記他のオレフィン系樹脂として、例えば、ポリエチレン、ポリプロピレン、及びエチレン−プロピレン共重合体等が挙げられる。   The polyolefin resin may further contain another olefin resin in addition to the metallocene polyethylene resin. Examples of the other olefin resin include polyethylene, polypropylene, and an ethylene-propylene copolymer.

上記発泡基材を形成するためのポリオレフィン系樹脂１００重量％中、上記メタロセン系ポリエチレン系樹脂の含有量は、好ましくは４０重量％以上、好ましくは１００重量％（全量）以下である。上記メタロセン系ポリエチレン系樹脂の含有量が上記下限以上であると、発泡基材の厚みが薄くても、発泡基材の２５％圧縮強度が高くなる。   The content of the metallocene-based polyethylene resin is preferably 40% by weight or more, and preferably 100% by weight (whole amount) or less in 100% by weight of the polyolefin resin for forming the foam base. When the content of the metallocene-based polyethylene resin is equal to or more than the above lower limit, even if the thickness of the foam substrate is thin, the 25% compressive strength of the foam substrate becomes high.

上記発泡基材は、架橋されていることが好ましい。従って、上記発泡基材は、ポリオレフィン系樹脂を架橋及び発泡させることにより得られることが好ましい。上記発泡基材が架橋されていることで、見かけ密度、及び、厚み方向の２５％圧縮強度を上記範囲に調整しやすくなり、衝撃吸収性を高めることが容易になる。   The foam substrate is preferably crosslinked. Therefore, the foam substrate is preferably obtained by crosslinking and foaming a polyolefin resin. By cross-linking the foamed base material, it becomes easy to adjust the apparent density and the 25% compressive strength in the thickness direction to the above-mentioned ranges, and it becomes easy to enhance the impact absorption.

上記ポリオレフィン発泡体を架橋させる方法は特に限定されず、例えば、発泡体に電子線、α線、β線又はγ線等の電離性放射線を照射する方法、並びに発泡体に予め配合しておいた有機過酸化物を加熱により分解させる方法等が挙げられる。   The method for crosslinking the above-mentioned polyolefin foam is not particularly limited. For example, the foam is irradiated with ionizing radiation such as electron beam, α ray, β ray or γ ray, and it is previously blended in the foam. The method etc. which decomposes | disassembles an organic peroxide by heating are mentioned.

上記発泡基材の製造方法は特に限定されない。上記発泡基材の製造方法として、ポリオレフィン系樹脂と発泡剤とを含有する発泡性樹脂組成物を調製し、この発泡性樹脂組成物を押出機を用いてシート状に押出加工する際に発泡剤を発泡させ、得られたシート状の発泡体を必要に応じて架橋させる方法が好ましい。   The manufacturing method of the said foaming base material is not specifically limited. As a method for producing the above-mentioned foam substrate, a foamable resin composition containing a polyolefin resin and a foaming agent is prepared, and the foamable resin composition is extruded into a sheet using an extruder. And the resulting sheet-like foam is optionally crosslinked.

［第１，第２の粘着剤層の詳細］
＜（メタ）アクリル系粘着剤＞
上記第１，第２の粘着剤層はそれぞれ、（メタ）アクリル系粘着剤により形成されており、（メタ）アクリル系粘着剤を含む。上記第１の粘着剤層に含まれる（メタ）アクリル系粘着剤と、上記第２の粘着剤層に含まれる（メタ）アクリル系粘着剤とは同一であってもよく、異なっていてもよい。 [Details of first and second pressure-sensitive adhesive layers]
<(Meth) acrylic adhesive>
The first and second pressure-sensitive adhesive layers are each formed of a (meth) acrylic pressure-sensitive adhesive, and include a (meth) acrylic pressure-sensitive adhesive. The (meth) acrylic pressure-sensitive adhesive contained in the first pressure-sensitive adhesive layer and the (meth) acrylic pressure-sensitive adhesive contained in the second pressure-sensitive adhesive layer may be the same or different. .

上記第１の粘着剤層に含まれる上記（メタ）アクリル系粘着剤及び上記第２の粘着剤層に含まれる上記（メタ）アクリル系粘着剤はそれぞれ、（メタ）アクリル重合体を含む。該（メタ）アクリル重合体には（メタ）アクリル共重合体が含まれる。上記第１の粘着剤層に含まれる上記（メタ）アクリル系粘着剤及び上記第２の粘着剤層に含まれる上記（メタ）アクリル系粘着剤はそれぞれ、重量平均分子量（Ｍｗ）の数平均分子量（Ｍｎ）に対する比（Ｍｗ／Ｍｎ）が１０以上、１５以下である（メタ）アクリル重合体を含むことが好ましい。（メタ）アクリル重合体の上記比（Ｍｗ／Ｍｎ）が上記下限以上及び上記上限以下であると、高い接着性と高い防水性との双方をより一層高いレベルで両立することができる。   The (meth) acrylic pressure-sensitive adhesive contained in the first pressure-sensitive adhesive layer and the (meth) acrylic pressure-sensitive adhesive contained in the second pressure-sensitive adhesive layer each include a (meth) acrylic polymer. The (meth) acrylic polymer includes a (meth) acrylic copolymer. The (meth) acrylic pressure-sensitive adhesive contained in the first pressure-sensitive adhesive layer and the (meth) acrylic pressure-sensitive adhesive contained in the second pressure-sensitive adhesive layer each have a number average molecular weight of weight average molecular weight (Mw) It is preferable to include a (meth) acrylic polymer having a ratio (Mw / Mn) to (Mn) of 10 or more and 15 or less. When the ratio (Mw / Mn) of the (meth) acrylic polymer is not less than the lower limit and not more than the upper limit, it is possible to achieve both high adhesion and high waterproofness at a still higher level.

高い接着性と高い防水性との双方をより一層高いレベルで両立する観点からは、上記（メタ）アクリル重合体の重量平均分子量（Ｍｗ）は好ましくは５０万以上、好ましくは７０万以下である。   From the viewpoint of achieving both high adhesion and high waterproofness at a still higher level, the weight average molecular weight (Mw) of the (meth) acrylic polymer is preferably 500,000 or more, preferably 700,000 or less .

上記比（Ｍｗ／Ｍｎ）及び上記重量平均分子量（Ｍｗ）を上記範囲に調整するためには、重合開始剤、重合温度等の重合条件を調整すればよい。   In order to adjust the above ratio (Mw / Mn) and the above weight average molecular weight (Mw) to the above ranges, polymerization conditions such as a polymerization initiator, polymerization temperature and the like may be adjusted.

上記重量平均分子量（Ｍｗ）及び上記数平均分子量（Ｍｎ）は、ゲルパーミエーションクロマトグラフィー（ＧＰＣ）により測定されるポリスチレン換算での重量平均分子量を示す。   The said weight average molecular weight (Mw) and said number average molecular weight (Mn) show the weight average molecular weight in polystyrene conversion measured by gel permeation chromatography (GPC).

上記（メタ）アクリル重合体は、ブチルアクリレートと２−エチルヘキシルアクリレートとを含むモノマー混合物を共重合して得られた（メタ）アクリル共重合体であることが好ましい。上記（メタ）アクリル重合体を構成する全モノマー（モノマー混合物）１００重量％中、ブチルアクリレートの含有量は好ましくは４０重量％以上、好ましくは８０重量％以下である。上記アクリル重合体を構成する全モノマー１００重量％中、２−エチルヘキシルアクリレートの含有量は好ましくは１０重量％以上、好ましくは４０重量％以下である。   The (meth) acrylic polymer is preferably a (meth) acrylic copolymer obtained by copolymerizing a monomer mixture containing butyl acrylate and 2-ethylhexyl acrylate. The content of butyl acrylate is preferably 40% by weight or more, and preferably 80% by weight or less, based on 100% by weight of all the monomers (monomer mixture) constituting the (meth) acrylic polymer. The content of 2-ethylhexyl acrylate is preferably 10% by weight or more, and preferably 40% by weight or less, based on 100% by weight of all the monomers constituting the acrylic polymer.

上記モノマー混合物は、必要に応じてブチルアクリレート及び２−エチルヘキシルアクリレート以外の共重合可能な他の重合性モノマーを含んでいてもよい。   The above-mentioned monomer mixture may optionally contain other copolymerizable polymerizable monomers other than butyl acrylate and 2-ethylhexyl acrylate.

上記共重合可能な他の重合性モノマーとして、例えば、（メタ）アクリル酸メチル、（メタ）アクリル酸エチル、（メタ）アクリル酸ｎ−プロピル、（メタ）アクリル酸イソプロピル等のアルキル基の炭素数が１〜３の（メタ）アクリル酸アルキルエステル；メタクリル酸トリデシル、（メタ）アクリル酸ステアリル等のアルキル基の炭素数が１３〜１８の（メタ）アクリル酸アルキルエステル；（メタ）アクリル酸イソボルニル、（メタ）アクリル酸ヒドロキシアルキル、グリセリンジメタクリレート、（メタ）アクリル酸グリシジル、２−メタクリロイルオキシエチルイソシアネート、（メタ）アクリル酸、イタコン酸、無水マレイン酸、クロトン酸、マレイン酸、フマル酸等の官能性モノマーが挙げられる。   As the other copolymerizable polymerizable monomers, for example, carbon number of alkyl group such as methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate and the like Is 1 to 3 (meth) acrylic acid alkyl ester; tridecyl methacrylate, (meth) acrylic acid stearyl etc. alkyl group having 13 to 18 carbon atoms (meth) acrylic acid alkyl ester; (meth) acrylic acid isobornyl, Hydroxyalkyl (meth) acrylate, glycerol dimethacrylate, glycidyl (meth) acrylate, 2-methacryloyloxyethyl isocyanate, (meth) acrylic acid, itaconic acid, maleic anhydride, crotonic acid, maleic acid, fumaric acid, etc. Monomers are included.

上記モノマー混合物を共重合させて上記（メタ）アクリル共重合体を得るには、上記モノマー混合物を、重合開始剤の存在下にてラジカル反応させる。上記モノマー混合物をラジカル反応させる方法、即ち、重合方法としては、従来公知の方法が用いられる。重合方法としては、例えば、溶液重合法（沸点重合法又は定温重合法）、乳化重合法、懸濁重合法、及び塊状重合法等が挙げられる。   To copolymerize the monomer mixture to obtain the (meth) acrylic copolymer, the monomer mixture is subjected to a radical reaction in the presence of a polymerization initiator. As a method of radically reacting the above monomer mixture, that is, as a polymerization method, conventionally known methods may be used. Examples of the polymerization method include a solution polymerization method (boiling point polymerization method or constant temperature polymerization method), an emulsion polymerization method, a suspension polymerization method, and a bulk polymerization method.

上記重合開始剤は特に限定されず、例えば、有機過酸化物、及びアゾ化合物等が挙げられる。上記有機過酸化物として、例えば、１，１−ビス（ｔ−ヘキシルパーオキシ）−３，３，５−トリメチルシクロヘキサン、ｔ−ヘキシルパーオキシピバレート、ｔ−ブチルパーオキシピバレート、２，５−ジメチル−２，５−ビス（２−エチルヘキサノイルパーオキシ）ヘキサン、ｔ−ヘキシルパーオキシ−２−エチルヘキサノエート、ｔ−ブチルパーオキシ−２−エチルヘキサノエート、ｔ−ブチルパーオキシイソブチレート、ｔ−ブチルパーオキシ−３，５，５−トリメチルヘキサノエート、及びｔ−ブチルパーオキシラウレート等が挙げられる。上記アゾ化合物として、例えば、アゾビスイソブチロニトリル、及びアゾビスシクロヘキサンカルボニトリル等が挙げられる。上記重合開始剤は単独で用いてもよいし、２種以上を併用してもよい。   The said polymerization initiator is not specifically limited, For example, an organic peroxide, an azo compound, etc. are mentioned. Examples of the organic peroxide include 1,1-bis (t-hexylperoxy) -3,3,5-trimethylcyclohexane, t-hexylperoxypivalate, t-butylperoxypivalate, and 2,5. -Dimethyl-2,5-bis (2-ethylhexanoylperoxy) hexane, t-hexylperoxy-2-ethylhexanoate, t-butylperoxy-2-ethylhexanoate, t-butylperoxy Isobutyrate, t-butylperoxy-3,5,5-trimethylhexanoate, t-butylperoxy laurate and the like can be mentioned. Examples of the azo compound include azobisisobutyronitrile, azobiscyclohexanecarbonitrile and the like. The polymerization initiators may be used alone or in combination of two or more.

高い接着性と高い防水性との双方をより一層高いレベルで両立する観点からは、上記第１の粘着剤層に含まれる上記（メタ）アクリル系粘着剤及び上記第２の粘着剤層に含まれる上記（メタ）アクリル系粘着剤はそれぞれ、粘着付与剤を含むことが好ましい。   From the viewpoint of achieving both high adhesion and high waterproofness at an even higher level, it is included in the (meth) acrylic pressure-sensitive adhesive and the second pressure-sensitive adhesive layer contained in the first pressure-sensitive adhesive layer. Each of the (meth) acrylic pressure-sensitive adhesives to be incorporated preferably contains a tackifier.

上記第１，第２の粘着剤層において、上記（メタ）アクリル重合体１００重量部に対する上記粘着付与樹脂の各含有量は好ましくは３６重量部以上、より好ましくは４１重量部以上、更に好ましくは４５重量部以上、好ましくは５０重量部以下である。上記粘着付与樹脂の含有量が上記下限以上であると、接着性及び防水性がより一層高くなり、上記内圧減少開始時間がより一層長くなる。   In the first and second pressure-sensitive adhesive layers, the content of each tackifying resin relative to 100 parts by weight of the (meth) acrylic polymer is preferably 36 parts by weight or more, more preferably 41 parts by weight or more, still more preferably It is 45 parts by weight or more, preferably 50 parts by weight or less. When the content of the tackifying resin is at least the lower limit, the adhesiveness and the waterproofness are further enhanced, and the internal pressure decrease start time is further lengthened.

上記粘着付与樹脂としては、例えば、ロジンエステル系樹脂、水添ロジン系樹脂、テルペン系樹脂、テルペンフェノール系樹脂、クマロンインデン系樹脂、脂環族飽和炭化水素系樹脂、Ｃ５系石油樹脂、Ｃ９系石油樹脂、及びＣ５−Ｃ９共重合系石油樹脂等が挙げられる。上記粘着付与樹脂は単独で用いてもよいし、２種以上を併用してもよい。   Examples of the tackifying resin include rosin ester resins, hydrogenated rosin resins, terpene resins, terpene phenol resins, coumarone indene resins, alicyclic saturated hydrocarbon resins, C5 petroleum resins, C9 And petroleum resins, and C5-C9 copolymer petroleum resins. The tackifier resins may be used alone or in combination of two or more.

上記第１，第２の粘着剤層では、架橋剤が添加されることにより上記第１，第２の粘着剤層を構成する樹脂（上記（メタ）アクリル重合体、及び上記（メタ）アクリル重合体と上記粘着付与樹脂）の主鎖間に架橋構造が形成されていることが好ましい。   In the first and second pressure-sensitive adhesive layers, a resin (the above (meth) acrylic polymer and the above (meth) acrylic resin constituting the first and second pressure-sensitive adhesive layers by the addition of a crosslinking agent It is preferable that a crosslinked structure be formed between the united body and the main chain of the tackifying resin).

上記架橋剤は特に限定されず、例えば、イソシアネート系架橋剤、アジリジン系架橋剤、エポキシ系架橋剤、及び金属キレート型架橋剤等が挙げられる。なかでも、イソシアネート系架橋剤が好ましい。上記第１，第２の粘着剤層にイソシアネート系架橋剤が添加されることで、イソシアネート系架橋剤のイソシアネート基と上記第１，第２の粘着剤層を構成する樹脂中のアルコール性水酸基とが反応して、上記第１，第２の粘着剤層の架橋が緩くなる。従って、上記第１，第２の粘着剤層において、断続的に加わる剥離応力を分散させることができ、強い衝撃が加わった場合に被着体の変形に伴って生じる剥離応力に対し、被着体からの剥離耐性がより向上する。   The said crosslinking agent is not specifically limited, For example, an isocyanate type crosslinking agent, an aziridine type crosslinking agent, an epoxy type crosslinking agent, a metal chelate type crosslinking agent etc. are mentioned. Among these, isocyanate crosslinking agents are preferred. By adding an isocyanate-based crosslinking agent to the first and second pressure-sensitive adhesive layers, the isocyanate group of the isocyanate-based crosslinking agent and the alcoholic hydroxyl group in the resin constituting the first and second pressure-sensitive adhesive layers React to loosen the crosslinking of the first and second pressure-sensitive adhesive layers. Therefore, in the first and second pressure-sensitive adhesive layers, the peeling stress applied intermittently can be dispersed, and the peeling stress caused by the deformation of the adherend when a strong impact is applied can be adhered. Resistance to exfoliation from the body is further improved.

上記（メタ）アクリル重合体１００重量部に対して、上記架橋剤の添加量は好ましくは０．０１重量部以上、より好ましくは０．１重量部以上、好ましくは１０重量部以下、より好ましくは３重量部以下である。   The amount of the crosslinking agent added is preferably 0.01 parts by weight or more, more preferably 0.1 parts by weight or more, preferably 10 parts by weight or less, based on 100 parts by weight of the (meth) acrylic polymer. It is 3 parts by weight or less.

上記第１，第２の粘着剤層の各ゲル分率は、好ましくは１５重量％以上、より好ましくは２０重量％以上、更に好ましくは２５重量％以上、特に好ましくは３０重量％以上、好ましくは６０重量％以下、より好ましくは５０重量％以下である。上記ゲル分率が上記下限以上及び上記上限以下であると、高い接着性と高い防水性との双方をより一層高いレベルで両立することができる。   The gel fraction of each of the first and second pressure-sensitive adhesive layers is preferably 15% by weight or more, more preferably 20% by weight or more, still more preferably 25% by weight or more, particularly preferably 30% by weight or more, preferably It is 60 wt% or less, more preferably 50 wt% or less. When the gel fraction is above the lower limit and below the upper limit, both high adhesion and high waterproofness can be achieved at a still higher level.

上記ゲル分率は以下のようにして測定される。   The gel fraction is measured as follows.

粘着剤層をＷ１（ｇ）採取し、採取した粘着剤層を酢酸エチル中に２３℃にて２４時間浸漬した際の不溶解分を２００メッシュの金網で濾過する。この金網上の残渣を１１０℃にて加熱乾燥し、得られた乾燥残渣の重量Ｗ２（ｇ）を測定し、下記式（１）によりゲル分率（架橋度）を算出する。   The pressure-sensitive adhesive layer is collected W1 (g), and the insoluble portion obtained by immersing the collected pressure-sensitive adhesive layer in ethyl acetate at 23 ° C. for 24 hours is filtered through a 200-mesh wire mesh. The residue on the wire mesh is dried by heating at 110 ° C., the weight W2 (g) of the obtained dried residue is measured, and the gel fraction (crosslinking degree) is calculated by the following formula (1).

ゲル分率（重量％）＝１００×Ｗ２／Ｗ１ （１）   Gel fraction (% by weight) = 100 × W2 / W1 (1)

上記第１，第２の粘着剤層の各厚みは、好ましくは５μｍ以上、より好ましくは７μｍ以上、更に好ましくは１０μｍ以上、特に好ましくは２５μｍ以上、好ましくは４００μｍ以下、より好ましくは２００μｍ以下、更に好ましくは１５０μｍ以下、特に好ましくは１００μｍ以下である。上記第１，第２の粘着剤層の各厚みが上記下限以上であると高い接着性と高い防水性との双方をより一層高いレベルで両立することができる。上記上限以下であると、両面粘着テープの厚み、及び両面粘着テープを用いた電子機器の厚みが薄くなる。   The thickness of each of the first and second pressure-sensitive adhesive layers is preferably 5 μm or more, more preferably 7 μm or more, still more preferably 10 μm or more, particularly preferably 25 μm or more, preferably 400 μm or less, more preferably 200 μm or less Preferably it is 150 micrometers or less, Especially preferably, it is 100 micrometers or less. When the thickness of each of the first and second pressure-sensitive adhesive layers is equal to or more than the lower limit, both high adhesion and high waterproofness can be achieved at a still higher level. The thickness of a double-sided adhesive tape and the thickness of the electronic device using a double-sided adhesive tape become thin as it is below the said upper limit.

［両面粘着テープの他の詳細］
上記粘着テープの厚みは、好ましくは５０μｍ以上、より好ましくは１５０μｍ以上、好ましくは２ｍｍ以下、より好ましくは１ｍｍ以下、更に好ましくは４００μｍ以下である。 [Other details of double-sided adhesive tape]
The thickness of the pressure-sensitive adhesive tape is preferably 50 μm or more, more preferably 150 μm or more, preferably 2 mm or less, more preferably 1 mm or less, and still more preferably 400 μm or less.

上記両面粘着テープの製造方法として、例えば、以下のような方法が挙げられる。   As a manufacturing method of the said double-sided adhesive tape, the following methods are mentioned, for example.

まず、（メタ）アクリル重合体に、必要に応じて粘着付与樹脂や架橋剤等を加え、また溶剤を加えて粘着剤Ａの溶液を作製する。この粘着剤Ａの溶液を発泡基材の表面に塗布する。溶液中の溶剤を完全に乾燥除去して、粘着剤層Ａを形成する。次に、形成された粘着剤層Ａの上に離型フィルムをその離型処理面が粘着剤層Ａに対向した状態に重ね合わせる。この結果、離型フィルム／粘着剤層Ａ／発泡基材の積層構造を有する第１の積層フィルムが得られる。   First, if necessary, a tackifying resin, a crosslinking agent and the like are added to the (meth) acrylic polymer, and a solvent is added to prepare a solution of the pressure-sensitive adhesive A. The solution of the pressure-sensitive adhesive A is applied to the surface of the foam substrate. The solvent in the solution is completely removed by drying to form a pressure-sensitive adhesive layer A. Next, a release film is superimposed on the formed pressure-sensitive adhesive layer A such that the release-treated surface of the release film faces the pressure-sensitive adhesive layer A. As a result, a first laminated film having a laminated structure of release film / adhesive layer A / foam base is obtained.

次いで、（メタ）アクリル重合体に、必要に応じて粘着付与樹脂や架橋剤等を加え、また溶剤を加えて粘着剤Ｂの溶液を作製し、上記離型フィルムとは別の離型フィルムを用意する。この離型フィルムの離型処理面に粘着剤Ｂの溶液を塗布し、溶液中の溶剤を完全に乾燥除去することにより、離型フィルムの表面に粘着剤層Ｂが形成する。この結果、離型フィルム／粘着剤層Ｂの積層構造を有する第２の積層フィルムを作製する。   Then, if necessary, a tackifying resin, a crosslinking agent, etc. are added to the (meth) acrylic polymer, and a solvent is added to prepare a solution of adhesive B, and a release film different from the above release film is prepared. prepare. A solution of pressure-sensitive adhesive B is applied to the release-treated surface of the release film, and the solvent in the solution is completely removed by drying to form an adhesive layer B on the surface of the release film. As a result, a second laminated film having a laminated structure of release film / adhesive layer B is produced.

得られた第１の積層フィルムの発泡基材の裏面に、第２の積層フィルムを粘着剤層Ｂ側から重ね合わせて積層体を得る。そして、上記積層体をゴムローラ等によって加圧することによって、発泡基材の両面に粘着剤層Ａ，Ｂを有し、かつ、粘着剤層Ａ，Ｂの各表面が離型フィルムで覆われた両面粘着テープが得られる。   The second laminate film is laminated from the pressure-sensitive adhesive layer B side on the back surface of the foam base of the obtained first laminate film to obtain a laminate. Then, by pressing the above laminate with a rubber roller or the like, both sides of the foam substrate have adhesive layers A and B, and both surfaces of the adhesive layers A and B are covered with a release film. An adhesive tape is obtained.

他の方法では、同様の要領で、離型フィルム／粘着剤層の積層構造を有する積層フィルムを２つ作製する。この２つの積層フィルムを粘着剤層側から発泡基材の両面のそれぞれに重ね合わせて積層体を作製する。この積層体をゴムローラ等によって加圧することによって、基材の両面に粘着剤層を有し、かつ、２つの粘着剤層の各表面が離型フィルムで覆われた両面粘着テープを得る。   In another method, two laminated films having a laminated structure of release film / adhesive layer are produced in the same manner. These two laminated films are laminated on the both sides of the foam substrate from the adhesive layer side to produce a laminate. By pressing this laminate with a rubber roller or the like, a double-sided pressure-sensitive adhesive tape is obtained, which has a pressure-sensitive adhesive layer on both sides of the substrate and in which each surface of the two pressure-sensitive adhesive layers is covered with a release film.

上記両面粘着テープの用途は特に限定されない。上記両面粘着テープは、電子機器用両面粘着テープであることが好ましく、携帯電子機器用両面粘着テープであることがより好ましい。上記両面粘着テープは、携帯電子機器を構成する部品を機器本体に接着固定するために用いられることがより好ましい。上記両面粘着テープは、例えば、携帯電子機器の液晶表示パネルを機器本体に接着固定する両面粘着テープとして特に用いることができる。   The application of the double-sided pressure-sensitive adhesive tape is not particularly limited. The double-sided pressure-sensitive adhesive tape is preferably a double-sided pressure-sensitive adhesive tape for an electronic device, and more preferably a double-sided pressure-sensitive adhesive tape for a portable electronic device. The double-sided pressure-sensitive adhesive tape is more preferably used to adhesively fix components constituting a portable electronic device to the device body. The double-sided pressure-sensitive adhesive tape can be particularly used, for example, as a double-sided pressure-sensitive adhesive tape for bonding and fixing a liquid crystal display panel of a portable electronic device to a device body.

これらの用途における上記両面粘着テープの形状は特に限定されないが、長方形、額縁状、円形、楕円形、及びドーナツ型等が挙げられる。   Although the shape of the said double-sided adhesive tape in these uses is not specifically limited, A rectangle, frame shape, circle, an ellipse, and a donut shape etc. are mentioned.

以下に実施例を挙げて本発明を更に詳しく説明する。本発明はこれら実施例のみに限定されない。   The present invention will be described in more detail by way of the following examples. The present invention is not limited to these examples.

（（メタ）アクリル共重合体（ａ）の調製）
温度計、攪拌機、冷却管を備えた反応器に、ブチルアクリレート７２重量部、２−エチルヘキシルアクリレート２０重量部、エチルアクリレート５重量部、アクリル酸３重量部、２−ヒドロキシエチルアクリレート０．１重量部、及び、酢酸エチル８０重量部を加え、窒素置換した。その後、反応器を加熱して還流を開始した。続いて、上記反応器内に、重合開始剤としてアゾビスイソブチロニトリル０．１重量部を添加した。７０℃で５時間還流させて、（メタ）アクリル共重合体（ａ）の溶液を得た。 (Preparation of (meth) acrylic copolymer (a))
In a reactor equipped with a thermometer, a stirrer and a condenser, 72 parts by weight of butyl acrylate, 20 parts by weight of 2-ethylhexyl acrylate, 5 parts by weight of ethyl acrylate, 3 parts by weight of acrylic acid, 0.1 parts by weight of 2-hydroxyethyl acrylate And 80 parts by weight of ethyl acetate were added and purged with nitrogen. The reactor was then heated to begin refluxing. Subsequently, 0.1 parts by weight of azobisisobutyronitrile as a polymerization initiator was added to the reactor. Refluxing at 70 ° C. for 5 hours gave a solution of (meth) acrylic copolymer (a).

得られた（メタ）アクリル共重合体（ａ）について、カラムとしてＷａｔｅｒ社製「２６９０ Ｓｅｐａｒａｔｉｏｎｓ Ｍｏｄｅｌ」を用いてＧＰＣ法により重量平均分子量（Ｍｗ）と数平均分子量（Ｍｎ）とを測定した。比（Ｍｗ／Ｍｎ）を算出したところ、１２．２であった。また、Ｍｗが６２万であった。   The weight average molecular weight (Mw) and the number average molecular weight (Mn) of the obtained (meth) acrylic copolymer (a) were measured by the GPC method using “2690 Separations Model” manufactured by Water as a column. The ratio (Mw / Mn) was calculated to be 12.2. Moreover, Mw was 620,000.

（（メタ）アクリル共重合体（ｂ）の調製）
ブチルアクリレート５８重量部、２−エチルヘキシルアクリレート３４重量部、エチルアクリレート５重量部、アクリル酸３重量部、及び２−ヒドロキシエチルアクリレート０．１重量部を用い、重合開始剤としてアゾビスイソブチロニトリル０．０５重量部を添加し、６０℃で８時間還流させたこと以外は（メタ）アクリル共重合体（ａ）と同様にして、比（Ｍｗ／Ｍｎ）が１０．５かつＭｗが６５万である（メタ）アクリル共重合体（ｂ）の溶液を得た。 (Preparation of (meth) acrylic copolymer (b))
Azobisisobutyronitrile as a polymerization initiator using 58 parts by weight of butyl acrylate, 34 parts by weight of 2-ethylhexyl acrylate, 5 parts by weight of ethyl acrylate, 3 parts by weight of acrylic acid, and 0.1 parts by weight of 2-hydroxyethyl acrylate The ratio (Mw / Mn) is 10.5 and the Mw is 650,000 in the same manner as the (meth) acrylic copolymer (a) except that 0.05 parts by weight is added and refluxing is carried out at 60 ° C. for 8 hours. A solution of (meth) acrylic copolymer (b) was obtained.

（（メタ）アクリル共重合体（ｃ）の調製）
ブチルアクリレート７９重量部、２−エチルヘキシルアクリレート１９重量部、アクリル酸３重量部、及び２−ヒドロキシエチルアクリレート０．２重量部を用い、重合開始剤としてアゾビスイソブチロニトリル０．３重量部を添加し、７０℃で５時間還流させたこと以外は（メタ）アクリル共重合体（ａ）と同様にして、比（Ｍｗ／Ｍｎ）が１３．１かつＭｗが６７万である（メタ）アクリル共重合体（ｃ）の溶液を得た。 (Preparation of (meth) acrylic copolymer (c))
Using 79 parts by weight of butyl acrylate, 19 parts by weight of 2-ethylhexyl acrylate, 3 parts by weight of acrylic acid, and 0.2 parts by weight of 2-hydroxyethyl acrylate, 0.3 parts by weight of azobisisobutyronitrile as a polymerization initiator (Meth) acrylic having a ratio (Mw / Mn) of 13.1 and Mw of 670,000 in the same manner as the (meth) acrylic copolymer (a) except for adding and refluxing at 70 ° C. for 5 hours A solution of copolymer (c) was obtained.

（（メタ）アクリル共重合体（ｄ）の調製）
ブチルアクリレート５０重量部、２−エチルヘキシルアクリレート３２重量部、エチルアクリレート１５重量部、アクリル酸３重量部、及び２−ヒドロキシエチルアクリレート０．２重量部を用い、重合開始剤としてアゾビスイソブチロニトリル０．０７重量部を添加し、７０℃で５時間還流させたこと以外は（メタ）アクリル共重合体（ａ）と同様にして、比（Ｍｗ／Ｍｎ）が１１．２かつＭｗが６５万である（メタ）アクリル共重合体（ｄ）の溶液を得た。 (Preparation of (meth) acrylic copolymer (d))
Azobisisobutyronitrile as a polymerization initiator using 50 parts by weight of butyl acrylate, 32 parts by weight of 2-ethylhexyl acrylate, 15 parts by weight of ethyl acrylate, 3 parts by weight of acrylic acid, and 0.2 parts by weight of 2-hydroxyethyl acrylate In the same manner as the (meth) acrylic copolymer (a) except that 0.07 parts by weight was added and refluxed at 70 ° C. for 5 hours, the ratio (Mw / Mn) was 11.2 and the Mw was 650,000. A solution of (meth) acrylic copolymer (d) is obtained.

（（メタ）アクリル共重合体（ｅ）の調製）
ブチルアクリレート５０重量部、２−エチルヘキシルアクリレート３２重量部、エチルアクリレート１５重量部、アクリル酸３重量部、及び２−ヒドロキシエチルアクリレート０．２重量部を用い、重合開始剤としてアゾビスイソブチロニトリル０．５重量部を添加し、８０℃で５時間還流させたこと以外は（メタ）アクリル共重合体（ａ）と同様にして、比（Ｍｗ／Ｍｎ）が１５．５かつＭｗが７０万である（メタ）アクリル共重合体（ｅ）の溶液を得た。 (Preparation of (meth) acrylic copolymer (e))
Azobisisobutyronitrile as a polymerization initiator using 50 parts by weight of butyl acrylate, 32 parts by weight of 2-ethylhexyl acrylate, 15 parts by weight of ethyl acrylate, 3 parts by weight of acrylic acid, and 0.2 parts by weight of 2-hydroxyethyl acrylate In the same manner as the (meth) acrylic copolymer (a) except that 0.5 parts by weight was added and refluxed at 80 ° C. for 5 hours, the ratio (Mw / Mn) was 15.5, and the Mw was 700,000. A solution of (meth) acrylic copolymer (e) was obtained.

（（メタ）アクリル共重合体（ｆ）の調製）
ブチルアクリレート５０重量部、２−エチルヘキシルアクリレート３２重量部、エチルアクリレート１５重量部、アクリル酸３重量部、及び２−ヒドロキシエチルアクリレート０．２重量部を用い、重合開始剤としてアゾビスイソブチロニトリル０．６重量部を添加し、８０℃で５時間還流させたこと以外は（メタ）アクリル共重合体（ａ）と同様にして、比（Ｍｗ／Ｍｎ）が１６．２かつＭｗが７０万である（メタ）アクリル共重合体（ｆ）の溶液を得た。 (Preparation of (meth) acrylic copolymer (f))
Azobisisobutyronitrile as a polymerization initiator using 50 parts by weight of butyl acrylate, 32 parts by weight of 2-ethylhexyl acrylate, 15 parts by weight of ethyl acrylate, 3 parts by weight of acrylic acid, and 0.2 parts by weight of 2-hydroxyethyl acrylate In the same manner as the (meth) acrylic copolymer (a) except that 0.6 parts by weight was added and refluxed at 80 ° C. for 5 hours, the ratio (Mw / Mn) was 16.2 and the Mw was 700,000. A solution of (meth) acrylic copolymer (f) is obtained.

（（メタ）アクリル共重合体（ｇ）の調製）
ブチルアクリレート５０重量部、２−エチルヘキシルアクリレート３２重量部、エチルアクリレート１５重量部、アクリル酸３重量部、及び２−ヒドロキシエチルアクリレート０．２重量部を用い、重合開始剤としてアゾビスイソブチロニトリル０．０３重量部を添加し、６０℃で５時間還流させたこと以外は（メタ）アクリル共重合体（ａ）と同様にして、比（Ｍｗ／Ｍｎ）が５．１かつＭｗが７０万である（メタ）アクリル共重合体（ｇ）の溶液を得た。 (Preparation of (meth) acrylic copolymer (g))
Azobisisobutyronitrile as a polymerization initiator using 50 parts by weight of butyl acrylate, 32 parts by weight of 2-ethylhexyl acrylate, 15 parts by weight of ethyl acrylate, 3 parts by weight of acrylic acid, and 0.2 parts by weight of 2-hydroxyethyl acrylate The ratio (Mw / Mn) is 5.1 and the Mw is 700,000 in the same manner as the (meth) acrylic copolymer (a) except that 0.03 parts by weight is added and refluxing is performed at 60 ° C. for 5 hours. A solution of (meth) acrylic copolymer (g) was obtained.

（（メタ）アクリル共重合体（ｈ）の調製）
ブチルアクリレート５０重量部、２−エチルヘキシルアクリレート３２重量部、エチルアクリレート１５重量部、アクリル酸３重量部、及び２−ヒドロキシエチルアクリレート０．２重量部を用い、重合開始剤としてアゾビスイソブチロニトリル０．０６重量部を添加し、６０℃で５時間還流させたこと以外は（メタ）アクリル共重合体（ａ）と同様にして、比（Ｍｗ／Ｍｎ）が９．５かつＭｗが７０万である（メタ）アクリル共重合体（ｈ）の溶液を得た。 (Preparation of (meth) acrylic copolymer (h))
Azobisisobutyronitrile as a polymerization initiator using 50 parts by weight of butyl acrylate, 32 parts by weight of 2-ethylhexyl acrylate, 15 parts by weight of ethyl acrylate, 3 parts by weight of acrylic acid, and 0.2 parts by weight of 2-hydroxyethyl acrylate The ratio (Mw / Mn) is 9.5 and the Mw is 700,000 in the same manner as the (meth) acrylic copolymer (a) except that 0.06 parts by weight is added and refluxed at 60 ° C. for 5 hours. A solution of (meth) acrylic copolymer (h) was obtained.

（実施例１）
得られた（メタ）アクリル共重合体（ａ）の溶液に含まれる（メタ）アクリル共重合体（ａ）の固形分１００重量部に対して、重合ロジンエステル１２重量部、テルペンフェノール１２重量部、水添ロジンエステル１２重量部、酢酸エチル（不二化学薬品社製）１２５重量部、及びイソシアネート系架橋剤（日本ポリウレタン社製「コロネートＬ４５」）２重量部を添加し、攪拌して、（メタ）アクリル系粘着剤（１）を得た。ここでは、重合ロジンエステル１２重量部、テルペンフェノール１２重量部、水添ロジンエステル１２重量部を用い、粘着付与樹脂を合計で３６重量部用いた。 Example 1
12 parts by weight of polymerized rosin ester and 12 parts by weight of terpene phenol with respect to 100 parts by weight of the solid content of (meth) acrylic copolymer (a) contained in the obtained solution of (meth) acrylic copolymer (a) Add 12 parts by weight of hydrogenated rosin ester, 125 parts by weight of ethyl acetate (manufactured by Fuji Chemical Co., Ltd.), and 2 parts by weight of an isocyanate type crosslinking agent (“Coronato L45” manufactured by Nippon Polyurethane Co., Ltd.) A meta) acrylic adhesive (1) was obtained. Here, 12 parts by weight of polymerized rosin ester, 12 parts by weight of terpene phenol, and 12 parts by weight of hydrogenated rosin ester were used, and a total of 36 parts by weight of tackifier resin was used.

離型紙（厚み１５０μｍ）を用意した。この離型紙の離型処理面にアクリル系粘着剤（１）を塗布し、１００℃で５分間乾燥させることにより、粘着剤層（厚み７５μｍ）を形成した。この粘着剤層を、架橋メタロセン系ポリエチレン発泡体（発泡基材、厚み１００μｍ、発泡倍率３倍、厚み方向の２５％圧縮強度：８０ｋＰａ）の表面と貼り合わせた。次いで、同様の要領で、この架橋メタロセン系ポリエチレン発泡体の反対の表面にも、上記と同じ粘着剤層を貼り合わせた。これにより、離型紙（厚み１５０μｍ）で両面が覆われた両面粘着テープを得た。   A release paper (thickness 150 μm) was prepared. An acrylic adhesive (1) was applied to the release-treated surface of the release paper, and dried at 100 ° C. for 5 minutes to form an adhesive layer (75 μm thick). The pressure-sensitive adhesive layer was bonded to the surface of a crosslinked metallocene-based polyethylene foam (foam base, 100 μm in thickness, 3 times of expansion ratio, 25% compressive strength in the thickness direction: 80 kPa). Then, in the same manner, the same pressure-sensitive adhesive layer as described above was laminated to the opposite surface of the crosslinked metallocene-based polyethylene foam. Thus, a double-sided pressure-sensitive adhesive tape in which both sides were covered with a release paper (thickness 150 μm) was obtained.

（実施例２〜１３及び比較例１〜３）
実施例１で用いた発泡基材を用い、（メタ）アクリル共重合体の種類、（メタ）アクリル共重合体１００重量部に対する粘着付与樹脂の配合量、１層あたりの粘着剤層の厚みを、下記の表１に示すように設定したこと以外は実施例１と同様にして、両面粘着テープを得た。 (Examples 2 to 13 and Comparative Examples 1 to 3)
Using the foamed substrate used in Example 1, the kind of (meth) acrylic copolymer, the blending amount of tackifier resin with respect to 100 parts by weight of (meth) acrylic copolymer, the thickness of the pressure-sensitive adhesive layer per layer A double-sided pressure-sensitive adhesive tape was obtained in the same manner as in Example 1 except that settings were made as shown in Table 1 below.

なお、粘着付与樹脂に関しては、重合ロジンエステルとテルペンフェノールと水添ロジンエステルとの重量比が１：１：１になるように、下記の表１に示す配合量で用いた。   With regard to the tackifying resin, the compounding amounts shown in Table 1 below were used such that the weight ratio of the polymerized rosin ester, the terpene phenol and the hydrogenated rosin ester was 1: 1: 1.

（評価）
（１）粘着剤層のゲル分率
粘着剤層をＷ１（ｇ）採取し、採取した粘着剤層を酢酸エチル中に２３℃にて２４時間浸漬した際の不溶解分を２００メッシュの金網で濾過する。この金網上の残渣を１１０℃にて加熱乾燥し、得られた乾燥残渣の重量Ｗ２（ｇ）を測定し、下記式（１）によりゲル分率（架橋度）を算出する。 (Evaluation)
(1) Gel fraction of pressure-sensitive adhesive layer W1 (g) was collected from the pressure-sensitive adhesive layer, and the collected adhesive layer was immersed in ethyl acetate at 23 ° C. for 24 hours. Filter The residue on the wire mesh is dried by heating at 110 ° C., the weight W2 (g) of the obtained dried residue is measured, and the gel fraction (crosslinking degree) is calculated by the following formula (1).

ゲル分率（重量％）＝１００×Ｗ２／Ｗ１ （１）   Gel fraction (% by weight) = 100 × W2 / W1 (1)

（２）加圧試験（防水性及び接着性の評価、特に防水性の評価）
図１（ａ）及び（ｂ）に示す状態で、加圧試験を行った。 (2) Pressure test (water resistance and adhesion evaluation, particularly water resistance evaluation)
A pressure test was conducted in the state shown in FIGS. 1 (a) and 1 (b).

得られた両面粘着テープを、長さ６１ｍｍ及び幅４９ｍｍの長方形の外形を有し、長さ５７ｍｍ及び幅４５ｍｍの長方形の内形を有し、かつ２ｍｍの幅を有するように切断して、枠状の両面粘着テープ１（試験片）を得た。   The obtained double-sided pressure-sensitive adhesive tape is cut so as to have a rectangular outer shape of 61 mm in length and 49 mm in width, a rectangular inner shape of 57 mm in length and 45 mm in width, and a width of 2 mm. -Shaped double-sided adhesive tape 1 (test piece) was obtained.

また、長さ１００ｍｍ、幅１００ｍｍ及び厚み１０ｍｍの長方形を有し、かつ貫通孔２ａを有する第１のアクリル板２（三菱レイヨン社製「アクリライト＠Ｌ」に貫通孔を形成した板）を用意した。貫通孔２ａは、直径１ｃｍの円形である。貫通孔２ａは、第１のアクリル板２の中心部に設けた。さらに、長さ１００ｍｍ、幅１００ｍｍ及び厚み１０ｍｍの矩形を有し、かつ貫通孔を有さない第２のアクリル板３（三菱レイヨン社製「アクリライト＠Ｌ）を用意した。   In addition, a first acrylic plate 2 (a plate in which through holes are formed in "Aklylite @ L" manufactured by Mitsubishi Rayon Co., Ltd.) having a rectangular shape 100 mm long, 100 mm wide and 10 mm thick and having a through hole 2a is prepared. did. The through hole 2a is a circle with a diameter of 1 cm. The through hole 2 a was provided at the center of the first acrylic plate 2. Furthermore, the 2nd acrylic board 3 ("Aklylite @ L" by Mitsubishi Rayon Co., Ltd.) which has a rectangle 100 mm in length, 100 mm in width, and 10 mm in thickness, and does not have a penetration hole was prepared.

枠状の両面粘着テープ１の一方の離型紙を剥離して、一方の粘着剤層を露出させ、第１のアクリル板２に中心部が揃うように貼り合わせた。枠状の両面粘着テープ１の他方の離型紙を剥離して、他方の粘着剤層を露出させ、第２のアクリル板３に中心部が揃うように貼り合わせた。   One release paper of the frame-shaped double-sided pressure-sensitive adhesive tape 1 was peeled off to expose one pressure-sensitive adhesive layer, and the two pieces of pressure-sensitive adhesive tape 1 were bonded to the first acrylic plate 2 so that the central portion was aligned. The other release paper of the frame-shaped double-sided pressure-sensitive adhesive tape 1 was peeled off, the other pressure-sensitive adhesive layer was exposed, and the second acrylic plate 3 was pasted so that the central part was aligned.

第１のアクリル板２と第２のアクリル板３とを枠状の両面粘着テープ１を介して積層して、荷重５ｋｇの力で１０秒間に押圧して貼り合わせた。第１のアクリル板２と第２のアクリル板３と枠状の両面粘着テープ１とで囲まれた内部空間１１Ａを有する積層体１１を得た。得られた積層体１１を２３℃で１日間放置した。この積層体１１を用いて、加圧試験（防水試験）を行った。   The first acrylic plate 2 and the second acrylic plate 3 were laminated via the frame-shaped double-sided pressure-sensitive adhesive tape 1 and pressed for 10 seconds with a force of 5 kg for bonding. The laminated body 11 which has the interior space 11A enclosed by the 1st acrylic board 2, the 2nd acrylic board 3, and the frame-like double-sided adhesive tape 1 was obtained. The resulting laminate 11 was left at 23 ° C. for 1 day. A pressure test (water proof test) was performed using this laminate 11.

具体的には、積層体１１における第１のアクリル板２の貫通孔２ａから積層体１１の内部空間１１Ａに空気を入れ、内部空間１１Ａの内圧を３０ｋＰａにする加圧試験を行った。加圧試験時には、枠状の両面粘着テープ１と第１のアクリル板２との接着界面、並びに枠状の両面粘着テープ１と第２のアクリル板３との接着界面を、水中に配置した。第１のアクリル板２の貫通孔２ａは、水面上に配置した。また、積層体１１の主面が水平状態になるように、第１，第２のアクリル板２，３の主面が水平状態になるように、積層体１１を配置した。   Specifically, air was introduced from the through holes 2a of the first acrylic plate 2 in the laminate 11 into the internal space 11A of the laminate 11 to perform a pressure test in which the internal pressure of the internal space 11A was 30 kPa. In the pressure test, the adhesion interface between the frame-shaped double-sided adhesive tape 1 and the first acrylic plate 2 and the adhesion interface between the frame-shaped double-sided adhesive tape 1 and the second acrylic plate 3 were placed in water. The through holes 2a of the first acrylic plate 2 were disposed on the water surface. Moreover, the laminated body 11 was arrange | positioned so that the main surfaces of the 1st, 2nd acrylic boards 2 and 3 might become horizontal state so that the main surface of the laminated body 11 might become horizontal state.

第１のアクリル板２の貫通孔２ａから、積層体１１の内部空間１１Ａに空気を圧入し、内部空間１１Ａの内圧を３０ｋＰａとした。この状態を維持して、接着界面からの空気が漏れ出すまでの時間を確認した。枠状の両面粘着テープ１と第１のアクリル板２及び第２のアクリル板３との少なくとも一方の界面で剥離が生じた場合には、接着界面から空気が漏れ出し、積層体１１の内部空間１１Ａの内圧が減少した。接着界面から空気が漏れ出すと、水中に気泡が確認された。   Air was pressed into the interior space 11A of the laminate 11 from the through holes 2a of the first acrylic plate 2, and the internal pressure of the interior space 11A was 30 kPa. Maintaining this state, the time until the air from the adhesive interface leaked was confirmed. When peeling occurs at the interface between at least one of the frame-like double-sided adhesive tape 1 and the first acrylic plate 2 and the second acrylic plate 3, air leaks from the bonding interface, and the internal space of the laminate 11 The internal pressure of 11A decreased. When air leaked from the adhesion interface, air bubbles were observed in the water.

枠状の両面粘着テープ１と第１のアクリル板２及び第２のアクリル板３との少なくとも一方の界面で剥離が生じることによって、積層体１１の内部空間１１Ａの内圧が減少し始めるまでの時間（内圧減少開始時間）を評価した。   The time until the internal pressure of the internal space 11A of the laminate 11 starts to decrease by peeling at the interface between at least one of the frame-like double-sided adhesive tape 1 and the first acrylic plate 2 and the second acrylic plate 3 The (internal pressure decrease start time) was evaluated.

（３）耐反発性試験（接着性の評価）
図２に示す状態で、耐反発性試験を行った。 (3) Repulsion resistance test (adhesion evaluation)
The repulsion resistance test was conducted in the state shown in FIG.

両面粘着テープ２１を幅２５ｍｍ、長さ１５０ｍｍに切断した。両面粘着テープ２１の一方の離型紙を剥離し、一方の粘着剤層を露出させた。また、幅２５ｍｍ、長さ１５０ｍｍ及び厚さ１ｍｍの第１のポリカーボネート板２２を用意した。両面粘着テープ２１の露出した面を貼り合わせた。   The double-sided pressure-sensitive adhesive tape 21 was cut into a width of 25 mm and a length of 150 mm. One release paper of the double-sided pressure-sensitive adhesive tape 21 was peeled off to expose one pressure-sensitive adhesive layer. In addition, a first polycarbonate plate 22 having a width of 25 mm, a length of 150 mm, and a thickness of 1 mm was prepared. The exposed surface of the double-sided adhesive tape 21 was bonded.

さらに、両面粘着テープ２１の他方の離型紙を剥離し、他方の粘着剤層を露出させた。また、幅２５ｍｍ、長さ２００ｍｍ及び厚さ１ｍｍの第２のポリカーボネート板２３を用意した。この第２のポリカーボネート板２３の長さ方向の中心部に、両面粘着テープ２１の露出した面を貼り合わせた。２枚の第１，第２のポリカーボネート板２２，２３の間に、両面粘着テープ２１が挟まれた積層サンプルを得た。その後、積層サンプルの第１のポリカーボネート板２２上に２．０ｋｇのゴムローラを載せて、３００ｍｍ／分の速度でゴムローラを一往復させることにより、第１，第２のポリカーボネート板２２，２３を両面粘着テープ２１を介して貼り合わせて、積層体３１を得た。その後、積層体３１を、２３℃で２４時間放置した。放置後の積層体３１を第２のポリカーボネート板２３が下側、第１のポリカーボネート板２２が上側となるように、幅２００ｍｍ、長さ１９０ｍｍ及び厚さ１０ｍｍのアルミニウム製の支持台２４の上に載せた。積層体３１が上側に突出して湾曲した形状となるように、積層体３１における第２のポリカーボネート板２３の両端を、支持台２４の長さ方向の両端に固定した。固定時の第２のポリカーボネート板２３の両端の間隔は１９０ｍｍに設定した。この固定状態で、以下の試験条件で冷熱サイクル試験を行った。   Furthermore, the other release paper of the double-sided pressure-sensitive adhesive tape 21 was peeled off to expose the other pressure-sensitive adhesive layer. Further, a second polycarbonate plate 23 having a width of 25 mm, a length of 200 mm and a thickness of 1 mm was prepared. The exposed surface of the double-sided pressure-sensitive adhesive tape 21 was bonded to the center of the second polycarbonate plate 23 in the longitudinal direction. A laminated sample in which the double-sided adhesive tape 21 was sandwiched between the two first and second polycarbonate plates 22 and 23 was obtained. Thereafter, a 2.0 kg rubber roller is placed on the first polycarbonate plate 22 of the laminated sample, and the rubber roller is caused to reciprocate at a speed of 300 mm / min to adhere the first and second polycarbonate plates 22 and 23 to both sides. It bonded together via the tape 21 and obtained the laminated body 31. Thereafter, the stack 31 was left at 23 ° C. for 24 hours. Place the laminate 31 after standing on a support base 24 made of aluminum with a width of 200 mm, a length of 190 mm and a thickness of 10 mm so that the second polycarbonate plate 23 is on the lower side and the first polycarbonate plate 22 is on the upper side. I put it on. Both ends of the second polycarbonate plate 23 in the laminated body 31 were fixed to both ends in the lengthwise direction of the support 24 so that the laminated body 31 had a curved shape projecting upward. The distance between both ends of the second polycarbonate plate 23 at the time of fixing was set to 190 mm. In this fixed state, a thermal cycle test was conducted under the following test conditions.

（試験条件）
温度条件：−４０℃〜９０℃、昇温速度：−４０℃〜９０℃まで３０分、降温速度：９０℃〜−４０℃まで３０分、相対湿度：６５％ＲＨ、冷熱サイクル：３０回 (Test conditions)
Temperature conditions: -40 ° C to 90 ° C, temperature rising rate: 30 minutes to -40 ° C to 90 ° C, temperature falling rate: 30 minutes to 90 ° C to -40 ° C, relative humidity: 65% RH, cold heat cycle: 30 times

上記冷熱サイクル試験を経た後、積層体を観察し、上側の第１のポリカーボネート板の端部が下側の第２のポリカーボネート板から、剥がれて浮いているか否かを観察した。   After passing through the above-mentioned thermal cycle test, the laminate was observed, and it was observed whether the end of the upper first polycarbonate plate peeled off from the lower second polycarbonate plate and floated.

［耐反発性試験の判定基準］
○：上側の第１のポリカーボネート板の端部が下側の第２のポリカーボネート板から剥がれておらず、浮いていない
×：上側の第１のポリカーボネート板の端部が下側の第２のポリカーボネート板から剥がれて浮いている [Criteria for rebound resistance test]
○: The end of the upper first polycarbonate plate is not peeled off from the lower second polycarbonate plate and does not float. ×: The end of the upper first polycarbonate plate is lower the second polycarbonate Peeling and floating from the board

詳細及び結果を下記の表１に示す。   Details and results are shown in Table 1 below.

Figure 2019077880
Figure 2019077880

１…枠状の両面粘着テープ
２…第１のアクリル板
２ａ…貫通孔
３…第２のアクリル板
１１…積層体
１１Ａ…内部空間
２１…両面粘着テープ
２２…第１のポリカーボネート板
２３…第２のポリカーボネート板
２４…支持台
３１…積層体 DESCRIPTION OF SYMBOLS 1 ... Frame shaped double-sided adhesive tape 2 ... 1st acrylic board 2a ... Through-hole 3 ... 2nd acrylic board 11 ... Laminated body 11A ... Internal space 21 ... Double-sided adhesive tape 22 ... 1st polycarbonate board 23 ... 2nd Polycarbonate plate 24 ... support base 31 ... laminate

Claims (7)

ポリオレフィン系樹脂により形成されている発泡基材と、
前記発泡基材の第１の表面側に配置されており、かつ、（メタ）アクリル系粘着剤により形成されている第１の粘着剤層と、
前記発泡基材の前記第１の表面側とは反対の第２の表面側に配置されており、かつ、（メタ）アクリル系粘着剤により形成されている第２の粘着剤層とを備え、
長さ６１ｍｍ及び幅４９ｍｍの矩形の外形を有し、長さ５７ｍｍ及び幅４５ｍｍの矩形の内形を有し、かつ２ｍｍの幅を有する枠状の両面粘着テープを用意し、長さ１００ｍｍ、幅１００ｍｍ及び厚み１０ｍｍの矩形を有し、かつ貫通孔を有する第１のアクリル板を用意し、長さ１００ｍｍ、幅１００ｍｍ及び厚み１０ｍｍの矩形を有し、かつ貫通孔を有さない第２のアクリル板を用意して、前記第１のアクリル板と前記第２のアクリル板とを前記枠状の両面粘着テープを介して貼り合わせて、前記第１のアクリル板と前記第２のアクリル板と前記枠状の両面粘着テープとで囲まれた内部空間を有する積層体を得て、前記積層体における前記第１のアクリル板の貫通孔から前記積層体の前記内部空間に空気を入れ、前記内部空間の内圧を３０ｋＰａにする加圧試験を行ったときに、
前記枠状の両面粘着テープと前記第１のアクリル板及び前記第２のアクリル板との少なくとも一方の界面で剥離が生じることによって、前記積層体の前記内部空間の内圧が減少し始めるまでの時間が５０分以上である、両面粘着テープ。 A foam base formed of a polyolefin resin,
A first pressure-sensitive adhesive layer disposed on the first surface side of the foam substrate, and formed of a (meth) acrylic pressure-sensitive adhesive;
And a second pressure-sensitive adhesive layer disposed on a second surface side opposite to the first surface side of the foam substrate and formed of a (meth) acrylic pressure-sensitive adhesive,
A frame-shaped double-sided pressure-sensitive adhesive tape having a rectangular outer shape of 61 mm in length and 49 mm in width, a rectangular inner shape of 57 mm in length and 45 mm in width, and a width of 2 mm is prepared. 100 mm in length, width A second acrylic plate having a rectangle of 100 mm and a thickness of 10 mm and having a through hole and having a length of 100 mm, a width of 100 mm and a thickness of 10 mm and having no through hole A plate is prepared, and the first acrylic plate and the second acrylic plate are pasted together via the frame-shaped double-sided adhesive tape, and the first acrylic plate, the second acrylic plate, and the second acrylic plate are prepared. A laminate having an internal space surrounded by a frame-shaped double-sided adhesive tape is obtained, and air is introduced into the internal space of the laminate from the through hole of the first acrylic plate in the laminate; Internal pressure of 30 When subjected to pressure test to Pa,
The time until the internal pressure of the internal space of the laminate starts to decrease by peeling at the interface between at least one of the frame-shaped double-sided adhesive tape and the first acrylic plate and the second acrylic plate Is 50 minutes or more, double-sided adhesive tape. 前記第１の粘着剤層に含まれる前記（メタ）アクリル系粘着剤が、（メタ）アクリル重合体と粘着付与樹脂を含み、前記第１の粘着剤層において、前記（メタ）アクリル重合体１００重量部に対する前記粘着付与樹脂の含有量が３６重量部以上、５０重量部以下であり、
前記第２の粘着剤層に含まれる前記（メタ）アクリル系粘着剤が、（メタ）アクリル重合体と粘着付与樹脂を含み、前記第２の粘着剤層において、前記（メタ）アクリル重合体１００重量部に対する前記粘着付与樹脂の含有量が３６重量部以上、５０重量部以下である、請求項１に記載の両面粘着テープ。 The (meth) acrylic pressure-sensitive adhesive contained in the first pressure-sensitive adhesive layer contains a (meth) acrylic polymer and a tackifier resin, and in the first pressure-sensitive adhesive layer, the (meth) acrylic polymer 100 The content of the tackifier resin is 36 parts by weight or more and 50 parts by weight or less with respect to the parts by weight,
The (meth) acrylic pressure-sensitive adhesive contained in the second pressure-sensitive adhesive layer contains a (meth) acrylic polymer and a tackifier resin, and in the second pressure-sensitive adhesive layer, the (meth) acrylic polymer 100 The double-sided pressure-sensitive adhesive tape according to claim 1, wherein a content of the tackifying resin with respect to a weight part is 36 parts by weight or more and 50 parts by weight or less. 前記第１の粘着剤層に含まれる前記（メタ）アクリル系粘着剤が、重量平均分子量の数平均分子量に対する比が１０以上、１５以下である（メタ）アクリル重合体を含み、
前記第２の粘着剤層に含まれる前記（メタ）アクリル系粘着剤が、重量平均分子量の数平均分子量に対する比が１０以上、１５以下である（メタ）アクリル重合体を含む、請求項１又は２に記載の両面粘着テープ。 The (meth) acrylic pressure-sensitive adhesive contained in the first pressure-sensitive adhesive layer contains a (meth) acrylic polymer having a ratio of weight average molecular weight to number average molecular weight of 10 or more and 15 or less,
The (meth) acrylic pressure-sensitive adhesive contained in the second pressure-sensitive adhesive layer contains a (meth) acrylic polymer having a ratio of weight average molecular weight to number average molecular weight of 10 or more and 15 or less. The double-sided adhesive tape as described in 2. 前記第１の粘着剤層に含まれる前記（メタ）アクリル系粘着剤が、（メタ）アクリル重合体と粘着付与樹脂を含み、前記第１の粘着剤層において、前記（メタ）アクリル重合体１００重量部に対する前記粘着付与樹脂の含有量が４０重量部以上、５０重量部以下であり、
前記第２の粘着剤層に含まれる前記（メタ）アクリル系粘着剤が、（メタ）アクリル重合体と粘着付与樹脂を含み、前記第２の粘着剤層において、前記（メタ）アクリル重合体１００重量部に対する前記粘着付与樹脂の含有量が４０重量部以上、５０重量部以下である、請求項１〜３のいずれか１項に記載の両面粘着テープ。 The (meth) acrylic pressure-sensitive adhesive contained in the first pressure-sensitive adhesive layer contains a (meth) acrylic polymer and a tackifier resin, and in the first pressure-sensitive adhesive layer, the (meth) acrylic polymer 100 The content of the tackifier resin is 40 parts by weight or more and 50 parts by weight or less with respect to the parts by weight,
The (meth) acrylic pressure-sensitive adhesive contained in the second pressure-sensitive adhesive layer contains a (meth) acrylic polymer and a tackifier resin, and in the second pressure-sensitive adhesive layer, the (meth) acrylic polymer 100 The double-sided pressure-sensitive adhesive tape according to any one of claims 1 to 3, wherein a content of the tackifier resin is 40 parts by weight or more and 50 parts by weight or less with respect to a part by weight. 前記第１の粘着剤層のゲル分率が１５重量％以上、５０重量％以下であり、
前記第２の粘着剤層のゲル分率が１５重量％以上、５０重量％以下である、請求項１〜４のいずれか１項に記載の両面粘着テープ。 The gel fraction of the first pressure-sensitive adhesive layer is 15% by weight or more and 50% by weight or less,
The double-sided pressure-sensitive adhesive tape according to any one of claims 1 to 4, wherein the gel fraction of the second pressure-sensitive adhesive layer is 15% by weight or more and 50% by weight or less. 前記発泡基材が、前記ポリオレフィン系樹脂を架橋及び発泡させることにより得られる、請求項１〜５のいずれか１項に記載の両面粘着テープ。   The double-sided pressure-sensitive adhesive tape according to any one of claims 1 to 5, wherein the foam substrate is obtained by crosslinking and foaming the polyolefin resin. 前記第１の粘着剤層の厚みが２５μｍ以上、１００μｍ以下であり、
前記第２の粘着剤層の厚みが２５μｍ以上、１００μｍ以下である、請求項１〜６のいずれか１項に記載の両面粘着テープ。 The thickness of the first pressure-sensitive adhesive layer is 25 μm or more and 100 μm or less,
The double-sided pressure-sensitive adhesive tape according to any one of claims 1 to 6, wherein the thickness of the second pressure-sensitive adhesive layer is 25 μm or more and 100 μm or less.
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