WO2024009529A1 - 粘着シート - Google Patents

粘着シート Download PDF

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Publication number
WO2024009529A1
WO2024009529A1 PCT/JP2022/045737 JP2022045737W WO2024009529A1 WO 2024009529 A1 WO2024009529 A1 WO 2024009529A1 JP 2022045737 W JP2022045737 W JP 2022045737W WO 2024009529 A1 WO2024009529 A1 WO 2024009529A1
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Prior art keywords
weight
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adhesive
parts
adhesive sheet
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/JP2022/045737
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English (en)
French (fr)
Japanese (ja)
Inventor
徹 田上
健一 山元
圭吾 下岡
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Nitto Denko Corp
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Nitto Denko Corp
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First worldwide family litigation filed litigation Critical https://patents.darts-ip.com/?family=87474533&utm_source=google_patent&utm_medium=platform_link&utm_campaign=public_patent_search&patent=WO2024009529(A1) "Global patent litigation dataset” by Darts-ip is licensed under a Creative Commons Attribution 4.0 International License.
Application filed by Nitto Denko Corp filed Critical Nitto Denko Corp
Priority to KR1020257001875A priority Critical patent/KR102807056B1/ko
Priority to CN202280097488.7A priority patent/CN119384475B/zh
Publication of WO2024009529A1 publication Critical patent/WO2024009529A1/ja
Anticipated expiration legal-status Critical
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    • 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
    • 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
    • C09J11/00—Features of adhesives not provided for in group C09J9/00, e.g. additives
    • C09J11/02—Non-macromolecular additives
    • C09J11/06—Non-macromolecular additives organic
    • 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
    • C09J11/00—Features of adhesives not provided for in group C09J9/00, e.g. additives
    • C09J11/08—Macromolecular additives
    • 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
    • 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
    • C09J161/00—Adhesives based on condensation polymers of aldehydes or ketones; Adhesives based on derivatives of such polymers
    • C09J161/04—Condensation polymers of aldehydes or ketones with phenols only
    • C09J161/06—Condensation polymers of aldehydes or ketones with phenols only of aldehydes with phenols
    • C09J161/14—Modified phenol-aldehyde condensates
    • 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
    • C09J175/00—Adhesives based on polyureas or polyurethanes; Adhesives based on derivatives of such polymers
    • C09J175/04—Polyurethanes
    • 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
    • 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
    • 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]

Definitions

  • the present invention relates to an adhesive sheet.
  • This application claims priority based on Japanese Patent Application No. 2022-108034 filed on July 4, 2022, and the entire contents of that application are incorporated herein by reference.
  • adhesives also referred to as pressure-sensitive adhesives, hereinafter the same
  • adhesives exhibit a soft solid (viscoelastic) state in a temperature range around room temperature, and have the property of adhering to adherends under pressure.
  • adhesives are used in various industrial fields such as home appliances, automobiles, various machines, electronic devices, etc., typically in the form of adhesive sheets containing a layer of the adhesive, for bonding parts and surfaces. It is widely used for protection purposes.
  • Some adhesive sheets are used for fixing components in portable devices such as mobile phones, smartphones, tablet computers, etc. Since these types of mobile devices are used while being carried around, they may be contaminated with secretions such as sebum and hand grime, chemicals such as cosmetics, hair conditioners, moisturizing creams, and sunscreens, or oils contained in foods. It's easy to do.
  • touch-panel mobile devices which have become increasingly popular in recent years, are equipped with a display/input section that also functions as an input section, and can be operated by the user directly touching the surface of the display/input section with their fingertips. Because of this, there are many opportunities for oil to adhere to the skin through the fingertips.
  • Patent Documents 1 and 2 are cited as technical documents regarding suppression of decrease in adhesive strength due to contact with oil.
  • the present invention has been made in view of the above circumstances, and achieves a high level of adhesion, suppressing the decrease in adhesive force due to contact with oil, and suppressing decrease in adhesive force due to contact with an aqueous solvent.
  • the purpose of this invention is to provide a pressure-sensitive adhesive sheet that can
  • a pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer containing an acrylic polymer and a tackifying resin.
  • the acrylic polymer is a polymer of monomer components containing n-heptyl acrylate.
  • the content of the tackifying resin in the adhesive layer is more than 10 parts by weight based on 100 parts by weight of the acrylic polymer.
  • the adhesive layer has a swelling degree of 100 or less with respect to ethyl acetate.
  • n-heptyl acrylate as a monomer component of the acrylic polymer, it is possible to suitably suppress a decrease in adhesive strength due to contact with an aqueous solvent. That is, according to the above configuration, it is possible to achieve both high levels of adhesive strength, suppression of decrease in adhesive force due to contact with oil (oil resistance), and suppression of decrease in adhesive force due to contact with aqueous solvent (resistance to aqueous solvent). be able to.
  • the monomer component contains 5.0% by weight or more of a carboxyl group-containing monomer.
  • a monomer component having such a composition tends to yield a pressure-sensitive adhesive sheet with higher adhesive strength.
  • the adhesive composition for forming the adhesive layer contains a combination of an isocyanate crosslinking agent and an epoxy crosslinking agent.
  • an isocyanate crosslinking agent and an epoxy crosslinking agent in combination, the degree of swelling of the adhesive layer can be adjusted appropriately, resulting in an adhesive that achieves a high level of adhesive strength, oil resistance, and aqueous solvent resistance.
  • a sheet can be suitably realized.
  • the adhesive layer includes a phenolic tackifier resin as the tackifier resin.
  • a phenolic tackifier resin as the tackifier resin.
  • the adhesive layer includes a terpene phenol resin as the phenolic tackifying resin.
  • a terpene phenol resin as the phenolic tackifying resin.
  • the content of the terpene phenol resin is preferably 20 parts by weight or more based on 100 parts by weight of the acrylic polymer.
  • the adhesive composition for forming the adhesive layer containing the phenolic tackifying resin preferably contains a combination of an isocyanate crosslinking agent and an epoxy crosslinking agent.
  • an acrylic polymer containing n-heptyl acrylate as a monomer component
  • a phenolic tackifying resin, an isocyanate crosslinking agent, and an epoxy crosslinking agent it has excellent adhesive strength, oil resistance, and aqueous solvent resistance. It is possible to more preferably realize a pressure-sensitive adhesive sheet that achieves both of the following at a high level.
  • the weight average molecular weight (Mw) of the acrylic polymer is preferably over 500,000. According to this aspect, it is easy to obtain a pressure-sensitive adhesive sheet that exhibits high levels of adhesive strength, oil resistance, and aqueous solvent resistance.
  • Adhesive sheets according to some preferred embodiments have a 180 degree peel strength against a stainless steel plate (adhesive strength against SUS) of 8.0 N/10 mm or more.
  • a pressure-sensitive adhesive sheet having such adhesive strength against SUS can exhibit high member fixing performance.
  • Adhesive sheets according to some preferred embodiments are configured as double-sided adhesive sheets. Since a double-sided adhesive sheet is used by attaching one surface and the other surface of the adhesive sheet to an adherend, oil and aqueous solvent are likely to enter the adhesive interface with the adherend. Therefore, it is particularly meaningful to apply the technology disclosed herein to suppress the decrease in adhesive strength caused by the oil content.
  • the pressure-sensitive adhesive sheet is configured as a double-sided pressure-sensitive adhesive sheet having a resin film as a support base material and the pressure-sensitive adhesive layer provided on one surface and the other surface of the support base material. ing.
  • a double-sided pressure-sensitive adhesive sheet having such a structure is advantageous from the viewpoint of processability into a desired shape and shape retention (for example, suppression of extrusion).
  • the adhesive sheet disclosed herein has a high level of adhesion, suppresses the decrease in adhesive force due to contact with oil, and suppresses decrease in adhesive force due to contact with an aqueous solvent, and is therefore suitable for use in mobile phones, for example. It is suitable for fixing members in devices (for example, portable electronic devices such as smartphones). Therefore, according to this specification, a mobile device using any of the adhesive sheets disclosed herein, in other words, a mobile device including the adhesive sheet is provided.
  • FIG. 1 is a cross-sectional view schematically showing the configuration of a pressure-sensitive adhesive sheet according to an embodiment.
  • FIG. 3 is a cross-sectional view schematically showing the configuration of a pressure-sensitive adhesive sheet according to another embodiment.
  • FIG. 3 is a cross-sectional view schematically showing the configuration of a pressure-sensitive adhesive sheet according to another embodiment.
  • FIG. 1 is a front view schematically showing an example of a portable device (portable electronic device) including an adhesive sheet.
  • the term "adhesive” as used herein refers to a material that exhibits a soft solid (viscoelastic) state in the temperature range around room temperature and has the property of easily adhering to an adherend under pressure. .
  • the adhesive referred to here generally has a complex tensile modulus E * (1Hz) as defined in "C. A. Dahlquist, “Adhesion: Fundamentals and Practice", McLaren & Sons, (1966) P. 143". ⁇ 10 7 dyne/cm 2 (typically, a material having the above properties at 25° C.).
  • biomass-derived carbon means carbon derived from biomass materials, that is, materials derived from renewable organic resources (renewable carbon).
  • biomass materials are typically materials derived from biological resources (typically plants that perform photosynthesis) that can be reproduced sustainably in the presence of sunlight, water, and carbon dioxide. means. Therefore, materials derived from fossil resources that are depleted through use after mining (fossil resource-based materials) are excluded from the concept of biomass materials here.
  • the biomass carbon ratio of the adhesive layer and the adhesive sheet that is, the proportion of biomass-derived carbon in the total carbon contained in the adhesive layer and the adhesive sheet, is the carbon isotope content with a mass number of 14 measured in accordance with ASTM D6866. It can be estimated from the amount.
  • the adhesive sheet disclosed herein includes an adhesive layer.
  • the above-mentioned pressure-sensitive adhesive sheet is, for example, a base material-less double-sided pressure-sensitive adhesive sheet comprising a first pressure-sensitive adhesive surface formed by one surface of the pressure-sensitive adhesive layer, and a second pressure-sensitive adhesive surface formed by the other surface of the pressure-sensitive adhesive layer.
  • the adhesive sheet disclosed herein may be in the form of a base-attached adhesive sheet in which the above-mentioned adhesive layer is laminated on one or both sides of a support base material.
  • the supporting base material may be simply referred to as "base material”.
  • adhesive sheet here may include what is called an adhesive tape, an adhesive label, an adhesive film, and the like.
  • the pressure-sensitive adhesive sheet disclosed herein may be in the form of a roll or a sheet. Alternatively, the adhesive sheet may be further processed into various shapes.
  • FIG. 1 The structure of a pressure-sensitive adhesive sheet according to one embodiment is schematically shown in FIG.
  • This adhesive sheet 1 is configured as a double-sided adhesive sheet without a base material, which includes an adhesive layer 21.
  • the adhesive sheet 1 has a first adhesive surface 21A constituted by one surface (first surface) of the adhesive layer 21 and a second adhesive surface constituted by the other surface (second surface) of the adhesive layer 21.
  • 21B are attached to different locations on the adherend.
  • the locations on which the adhesive surfaces 21A and 21B are attached may be on different members, or may be on different locations within a single member. As shown in FIG.
  • the adhesive sheet 1 before use (that is, before being attached to an adherend) has a first adhesive surface 21A and a second adhesive surface 21B that are peeled off at least on the side facing the adhesive layer 21. It may be a component of the adhesive sheet 100 with a release liner that is protected by the release liners 31 and 32 serving as surfaces.
  • the release liners 31 and 32 it is preferable to use, for example, a sheet-like base material (liner base material) that is constructed by providing a release layer made of a release treatment agent on one side so that one side becomes a release surface. obtain.
  • the release liner 32 may be omitted and a release liner 31 having release surfaces on both sides may be used, and this and the adhesive sheet 1 may be overlapped and spirally wound so that the second adhesive surface 21B is on the release liner 31.
  • the pressure-sensitive adhesive sheet with a release liner may be in a protected form (roll form) in contact with the back surface of the adhesive sheet.
  • FIG. 2 The structure of a pressure-sensitive adhesive sheet according to another embodiment is schematically shown in FIG. 2.
  • This adhesive sheet 2 is a base material comprising a sheet-shaped support base material (for example, a resin film) 10 having a first surface 10A and a second surface 10B, and an adhesive layer 21 provided on the first surface 10A side. It is constructed as a single-sided adhesive sheet.
  • the adhesive layer 21 is fixedly provided on the first surface 10A side of the support base material 10, that is, without the intention of separating the adhesive layer 21 from the support base material 10. As shown in FIG.
  • the pressure-sensitive adhesive sheet 2 before use has a surface (adhesive surface) 21A of the pressure-sensitive adhesive layer 21 protected by a release liner 31 having a release surface at least on the side facing the pressure-sensitive adhesive layer 21. It may be a component of the pressure-sensitive adhesive sheet 200 with a release liner. Alternatively, the release liner 31 may be omitted, the second surface 10B may be the release surface, and the adhesive sheet 2 may be wound so that the adhesive surface 21A is the second surface (back surface) of the support substrate 10. ) 10B may be in a protected form (roll form).
  • FIG. 3 schematically shows the structure of a pressure-sensitive adhesive sheet according to yet another embodiment.
  • This adhesive sheet 3 includes a sheet-shaped support base material (for example, a resin film) 10 having a first surface 10A and a second surface 10B, and a first adhesive layer 21 fixedly provided on the first surface 10A side. and a second adhesive layer 22 fixedly provided on the second surface 10B side.
  • 32 may be a component of the adhesive sheet 300 with a release liner.
  • the release liner 32 may be omitted and a release liner 31 having release surfaces on both sides may be used, and this and the adhesive sheet 3 may be overlapped and spirally wound so that the second adhesive surface 22A is on the release liner 31.
  • the pressure-sensitive adhesive sheet with a release liner may be in a protected form (roll form) in contact with the back surface of the adhesive sheet.
  • the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer are the pressure-sensitive adhesive layer described below.
  • the other adhesive layer e.g., the second adhesive layer
  • the adhesive layer disclosed herein specifically, the one adhesive layer described above
  • the adhesive layer may have a different composition from the adhesive layer (for example, the first adhesive layer).
  • the other pressure-sensitive adhesive layer may be formed from a known or commonly used pressure-sensitive adhesive, for example.
  • the adhesive layer constituting the adhesive sheet disclosed herein includes an acrylic polymer and a tackifier resin.
  • the adhesive layer is typically an adhesive layer using the acrylic polymer as a base polymer.
  • Such an adhesive layer is also referred to as an acrylic adhesive layer.
  • the base polymer of the adhesive layer refers to the main component of the rubbery polymer (polymer exhibiting rubber elasticity in a temperature range around room temperature) contained in the adhesive layer.
  • the term "main component” refers to a component contained in an amount exceeding 50% by weight, unless otherwise specified.
  • the following description regarding the adhesive and the components that can be included in the adhesive layer is also applicable to the adhesive composition used to form the adhesive (layer), unless otherwise specified.
  • the term "acrylic polymer” refers to a polymer containing monomer units derived from a monomer having at least one (meth)acryloyl group in one molecule, as monomer units constituting the polymer. .
  • a monomer having at least one (meth)acryloyl group in one molecule will also be referred to as an "acrylic monomer.”
  • an acrylic polymer in this specification is defined as a polymer containing monomer units derived from acrylic monomers.
  • (meth)acryloyl” refers comprehensively to acryloyl and methacryloyl.
  • (meth)acrylate” comprehensively refers to acrylate and methacrylate
  • (meth)acrylic” comprehensively refers to acrylic and methacrylic.
  • n-HpA n-heptyl acrylate
  • BA n-butyl acrylate
  • this adhesive Compared to acrylic polymers polymerized using monomer components whose composition is replaced with other alkyl acrylates such as 2-ethylhexyl acrylate (2EHA) and 2-ethylhexyl acrylate (2EHA), this adhesive has a high level of adhesive strength, oil resistance, and aqueous solvent resistance. It has been found that this method is suitable for realizing sheets. More specifically, compared to, for example, a configuration in which n-HpA is replaced with 2EHA, it is easier to suppress the degree of swelling and improve adhesive strength, and compared to, for example, a configuration in which n-HpA is replaced with BA, it is easier to improve adhesive strength in an aqueous solvent.
  • 2EHA 2-ethylhexyl acrylate
  • BA 2-ethylhexyl acrylate
  • the polymer containing n-HpA as a monomer unit has a low glass transition temperature, which allows the adhesive layer to adhere well to the adherend, allowing both
  • the polymer containing n-HpA has a relatively long linear side chain derived from n-HpA, so it has good compatibility with tackifying resins, making it easy to apply tack.
  • the side chain derived from n-HpA has a higher affinity than the side chain derived from alkyl acrylate with a larger number of carbon atoms.
  • side chains derived from n-HpA have lower hydrophilicity than side chains derived from alkyl acrylates with a smaller number of carbon atoms (e.g. BA), so they can be used in aqueous solvents (e.g. mixed solvents of water and lower alcohols). This is thought to be because it is easier to suppress the decrease in adhesive strength due to contact with ).
  • the proportion of n-HpA in the monomer components of the acrylic polymer is suitably 50% by weight or more (for example, more than 50% by weight), preferably 70% by weight or more, more preferably It is 80% by weight or more, more preferably 85% by weight or more, particularly preferably 90% by weight or more, may be 91% by weight or more, may be 92% by weight or more, may be 94% by weight or more, and is 94.5% by weight or more. But that's fine. By increasing the amount of n-HpA used, the effects of its use tend to be expressed more effectively. In some embodiments, the proportion of n-HpA in the monomer component can be 98% or more, or 99% or more, or 100% by weight.
  • the proportion of n-HpA in the monomer component is 99.5% by weight or less, from the viewpoint of easily suppressing the degree of swelling of the adhesive layer and adjusting the balance of properties. It is suitable that the content is 97% by weight or less (for example, less than 97% by weight), more preferably 96% by weight or less, even more preferably 95% by weight or less, it may be 94% by weight or less, and 93% by weight or less. It may be 91% by weight or less.
  • the acrylic polymer may be copolymerized with an alkyl (meth)acrylate (hereinafter also referred to as "optional alkyl (meth)acrylate”) other than n-HpA.
  • an alkyl (meth)acrylate hereinafter also referred to as "optional alkyl (meth)acrylate
  • a compound represented by the following formula (1) can be suitably used.
  • CH 2 C(R 1 )COOR 2 (1)
  • R 1 in the above formula (1) is a hydrogen atom or a methyl group.
  • R 2 is a chain alkyl group having 1 to 20 carbon atoms (excluding n-heptyl group).
  • optional alkyl (meth)acrylate examples include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, s -Butyl (meth)acrylate, pentyl (meth)acrylate, isopentyl (meth)acrylate, hexyl (meth)acrylate, heptyl methacrylate, 2-ethylhexyl (meth)acrylate, octyl (meth)acrylate, isooctyl (meth)acrylate, nonyl ( meth)acrylate, isononyl(meth)acrylate, decyl(meth)acrylate, isodecyl(meth)acrylate, undecyl(meth)acrylate, lauryl(meth)acryl
  • optional alkyl (meth)acrylates can be used alone or in combination of two or more.
  • Optional alkyl (meth)acrylates that may be preferably used include n-butyl acrylate (BA) and 2-ethylhexyl acrylate (2EHA). These optional alkyl (meth)acrylates can be used alone or in combination of two or more.
  • the proportion of optional alkyl (meth)acrylates contained in the monomer component is 50% by weight from the viewpoint of facilitating the use effect of n-HpA. % (for example, 49.5% by weight or less), preferably less than 47% by weight, more preferably 45% by weight or less, still more preferably 40% by weight or less, and may be 30% by weight or less. , 10% by weight or less, 5% by weight or less, or 1% by weight or less.
  • the above optional alkyl (meth)acrylate contained in the monomer component From the viewpoint of oil resistance, etc., the proportion (total proportion of two or more types) is suitably 30% by weight or less, preferably 20% by weight or less, more preferably 10% by weight or less. It may be 5% by weight or less, 1% by weight or less, or 0.5% by weight or less.
  • the proportion (2 types) of the above optional alkyl (meth)acrylate contained in the monomer component From the viewpoint of resistance to aqueous solvents, it is appropriate that the total proportion of the above is 30% by weight or less, preferably 20% by weight or less, more preferably 10% by weight or less. It may be 5% by weight or less, 1% by weight or less, or 0.5% by weight or less.
  • the techniques disclosed herein may be preferably practiced in such a manner that the monomer component is substantially free of any alkyl (meth)acrylate.
  • the monomer component does not substantially contain monomer A (for example, the above-mentioned optional alkyl (meth)acrylate), it means that the monomer A is not used, at least intentionally, and the monomer component is For example, unintentional inclusion of about 0.01% by weight or less is acceptable.
  • monomer A for example, the above-mentioned optional alkyl (meth)acrylate
  • the monomer component may include an alkyl (meth)acrylate having a biomass-derived alkyl group at the ester end (hereinafter also referred to as "biomass alkyl (meth)acrylate”).
  • biomass alkyl (meth)acrylate having a biomass-derived alkyl group at the ester end
  • biomass alkyl (meth)acrylate it is possible to suitably realize an acrylic pressure-sensitive adhesive that is designed to reduce dependence on fossil resource-based materials.
  • the biomass alkyl (meth)acrylate is not particularly limited, and is, for example, an ester of a biomass-derived alkanol and a biomass-derived or non-biomass-derived (meth)acrylic acid.
  • alkanols derived from biomass include biomass ethanol, alkanols derived from plant materials such as palm oil, palm kernel oil, coconut oil, and castor oil.
  • the biomass-derived alkanol has three or more carbon atoms, the alkanol may be linear or branched.
  • an ester of a biomass-derived alkanol and a non-biomass-derived (meth)acrylic acid is used as the biomass alkyl (meth)acrylate used in the synthesis of the acrylic polymer.
  • biomass alkyl (meth)acrylate In such a biomass alkyl (meth)acrylate, the greater the number of carbon atoms in the alkanol, the greater the number ratio of biomass-derived carbon to the total number of carbons contained in the biomass alkyl (meth)acrylate, that is, the biomass carbon ratio of the alkyl (meth)acrylate. becomes higher. Therefore, in the above-mentioned biomass alkyl (meth)acrylate, it is desirable that the alkyl group derived from biomass has a large number of carbon atoms in order to reduce dependence on fossil resource materials.
  • biomass-derived n-heptyl acrylate (biomass n-HpA) is used as n-heptyl acrylate.
  • biomass n-HpA is an ester of a biomass-derived alkanol and a biomass-derived or non-biomass-derived acrylic acid.
  • an ester of a biomass-derived alkanol and a non-biomass-derived acrylic acid can be used. In such compounds, only the linear heptyl groups are derived from biomass.
  • the proportion of biomass alkyl (meth)acrylate (preferably biomass n-HpA) in the monomer components of the acrylic polymer is 50% by weight or more (for example, more than 50% by weight), and is preferably is 70% by weight or more, more preferably 80% by weight or more, further preferably 85% by weight or more, particularly preferably 90% by weight or more, may be 92% by weight or more, may be 94% by weight or more, and may be 96% by weight or more. But that's fine.
  • the proportion of biomass alkyl (meth)acrylate (preferably biomass n-HpA) among the monomer components is less than 97% by weight, and in some embodiments may be 95% by weight or less, and in some embodiments may be 93% by weight. It may be less than 91% by weight. In some other embodiments, the proportion of biomass alkyl (meth)acrylate in the monomer component may be 90% by weight or less, 70% by weight or less, 50% by weight or less, 30% by weight or less, It may be 10% by weight or less, or 1% by weight or less.
  • the monomer component of the acrylic polymer preferably includes a carboxy group-containing monomer.
  • Carboxy group-containing monomers can help improve adhesive strength by improving cohesiveness based on their polarity. In addition, they can also suppress excessive swelling of the adhesive layer due to oil content, and suppress the decrease in adhesive strength due to contact with oil content (for example, as described below). This can contribute to improving the adhesive force retention rate ( RA ). Further, since the above-mentioned carboxyl group can serve as a crosslinking point of the acrylic polymer, there is an advantage that the degree of swelling of the pressure-sensitive adhesive layer can be easily adjusted.
  • carboxy group-containing monomers examples include acrylic acid (AA), methacrylic acid (MAA), carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid, isocrotonic acid, etc. be done.
  • preferred carboxy group-containing monomers include AA and MAA.
  • AA is particularly preferred.
  • Carboxy group-containing monomers can be used singly or in combination of two or more.
  • the proportion of the carboxy group-containing monomer in the monomer component of the acrylic polymer may be, for example, 0.5% by weight or more, 1.0% by weight or more, or 2.0% by weight or more. In some embodiments, the proportion of the carboxy group-containing monomer in the monomer component of the acrylic polymer is suitably greater than 3.0% by weight, advantageously 3.5% by weight or more; It is preferably 4.0% by weight or more, more preferably 4.5% by weight or more or 5.0% by weight or more.
  • the proportion of the carboxy group-containing monomer in the monomer component may be more than 5.0% by weight, may be 5.5% by weight or more, and may be 6.0% by weight or more. , 7.0% by weight or more, 8.0% by weight or more (for example, more than 8.0% by weight), or 9.0% by weight or more.
  • the amount of the carboxyl group-containing monomer is, for example, suitably 20% by weight or less of the total monomer components, and preferably 15% by weight or less, from the viewpoint of suppressing a decrease in adhesive strength due to contact with an aqueous solvent. More preferably, it is 12% by weight or less.
  • the amount of the carboxy group-containing monomer may be less than 10% by weight, may be less than 9% by weight, may be less than 8% by weight, may be less than 6% by weight, and may be less than 5% by weight. But that's fine.
  • the acrylic polymer may be copolymerized with a functional group-containing monomer other than the carboxy group-containing monomer.
  • functional group-containing monomers other than carboxy group-containing monomers are also referred to as "functional group-containing monomers B."
  • the functional group-containing monomer B that can introduce a functional group that can serve as a crosslinking point into the acrylic polymer or contribute to improving adhesive strength, monomers containing hydroxyl groups (OH groups) (2-hydroxyethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2- Hydroxyalkyl (meth)acrylates such as hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate; polypropylene glycol mono(meth)acrylate, etc.
  • OH groups hydroxyl groups
  • 2-hydroxyethyl (meth)acrylate 2-hydroxyethyl (meth)acrylate
  • acid anhydride group-containing monomers acid anhydride group-containing monomers, amide group-containing monomers ((meth)acrylamide, N,N-dimethyl(meth)acrylamide, etc.), amino group-containing monomers (aminoethyl (meth)acrylate, N,N-dimethylaminoethyl (meth)acrylate, etc.), epoxy group-containing monomers, cyano group-containing monomers, keto group-containing monomers, monomers with nitrogen atom-containing rings (N-vinyl-2-pyrrolidone, N-(meth)acryloylmorpholine, etc.), alkoxysilyl Examples include group-containing monomers, imide group-containing monomers, and the like.
  • the above functional group-containing monomers B can be used alone or in combination of two or more.
  • the monomer component constituting the acrylic polymer contains the functional group-containing monomer B
  • the monomer component may contain the carboxy group-containing monomer or may not substantially contain it.
  • the content of the functional group-containing monomer B in the monomer component is not particularly limited.
  • the content of the functional group-containing monomer B in the monomer component can be, for example, 0.1% by weight or more, and 0.5% by weight or more. It is appropriate that the amount is 1% by weight or more.
  • the content of the functional group-containing monomer B in the monomer component is 40% by weight or less.
  • the content of functional group-containing monomer B in the monomer component is, for example, less than 3% by weight, may be less than 1% by weight, may be less than 0.5% by weight, and may be less than 0.3% by weight. % or less than 0.1% by weight.
  • the technique disclosed herein can be preferably carried out in an embodiment in which the monomer component of the acrylic polymer does not substantially contain the functional group-containing monomer B.
  • a hydroxyl group-containing monomer when used as the functional group-containing monomer B, its content may be, for example, approximately 0.001% by weight or more of the total monomer components, or approximately 0.01% by weight or more, It may be approximately 0.02% by weight or more.
  • the content of the hydroxyl group-containing monomer is suitably about 10% by weight or less, preferably about 5% by weight or less, more preferably about 2% by weight or less, based on the total monomer components.
  • the content of hydroxyl group-containing monomer in the monomer component may be less than 1% by weight, may be less than 0.5% by weight, may be less than 0.3% by weight, and may be less than 0.1% by weight. % or less than 0.01% by weight.
  • the monomer component of the acrylic polymer may be substantially free of hydroxyl group-containing monomers. According to the technology disclosed herein, desired effects can be achieved without relying on hydroxyl group-containing monomers.
  • the proportion of the carboxy group-containing monomer to the total functional group-containing monomers (total functional group-containing monomers including the carboxy group-containing monomer) contained in the monomer component. is suitably 30% by weight or more, preferably 50% by weight or more, more preferably 70% by weight or more, still more preferably 80% by weight, from the viewpoint of effectively exhibiting the effect of copolymerizing the carboxyl group-containing monomer.
  • the above is particularly preferably 90% by weight or more, for example, 95% by weight or more, 97% by weight or more, 98% by weight or more, 99% by weight or more (for example, 99.9% by weight). % or more).
  • the upper limit of the proportion of the carboxy group-containing monomer in the total of the functional group-containing monomers is 100% by weight, which corresponds to an embodiment in which the functional group-containing monomer B is not used.
  • the proportion of the carboxy group-containing monomer in the entire functional group-containing monomer may be, for example, 95% by weight or less.
  • the monomer components constituting the acrylic polymer may contain copolymerization components other than the above-mentioned functional group-containing monomers for the purpose of improving cohesive force and the like.
  • copolymerization components include vinyl ester monomers such as vinyl acetate; aromatic vinyl compounds such as styrene; cycloalkyl (meth)acrylates such as cyclohexyl (meth)acrylate, cyclopentyl (meth)acrylate, and isobornyl ) acrylates; aryl (meth)acrylates (e.g. phenyl (meth)acrylate), aryloxyalkyl (meth)acrylates (e.g.
  • Aromatic ring-containing (meth)acrylate Olefinic monomer; Chlorine-containing monomer; Isocyanate group-containing monomer such as 2-(meth)acryloyloxyethyl isocyanate; Alkoxy such as methoxyethyl (meth)acrylate and ethoxyethyl (meth)acrylate Group-containing monomers; vinyl ether monomers such as methyl vinyl ether and ethyl vinyl ether; and the like.
  • the other copolymerization components mentioned above can be used alone or in combination of two or more.
  • the amount of such other copolymer components is not particularly limited and may be selected appropriately depending on the purpose and use, but from the viewpoint of appropriately exerting the effect of use, it should be 0.05% by weight or more in the monomer components. is suitable, and may be 0.5% by weight or more.
  • the content of other copolymer components in the monomer component is 20% by weight or less.
  • the content is preferably 10% by weight or less, more preferably 8% by weight or less, still more preferably less than 5% by weight, and may be less than 3% by weight, for example, less than 1% by weight.
  • the technology disclosed herein can also be preferably practiced in an embodiment in which the monomer component does not substantially contain other copolymer components.
  • the monomer component constituting the acrylic polymer is a polyfunctional monomer having at least two polymerizable functional groups (typically radically polymerizable functional groups) having an unsaturated double bond such as a (meth)acryloyl group or a vinyl group. May include.
  • a polyfunctional monomer as a monomer component, the cohesive force of the adhesive layer can be increased and the degree of swelling can be suppressed.
  • the polyfunctional monomer is not particularly limited, and includes, for example, 1,6-hexanediol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, and neopentyl glycol di(meth)acrylate. etc.
  • One type of polyfunctional monomer can be used alone or two or more types can be used in combination.
  • the lower limit of the amount used when using a polyfunctional monomer is not particularly limited, as long as it is greater than 0% by weight.
  • the amount of the polyfunctional monomer to be used can be appropriately set so that the intended use of the polyfunctional monomer is achieved.
  • the effect of using the polyfunctional monomer can be appropriately exhibited by setting the amount of the polyfunctional monomer to be approximately 0.001% by weight or more (for example, approximately 0.01% by weight or more) of the monomer components.
  • the amount of the polyfunctional monomer used is preferably about 3% by weight or less of the monomer components, and about 2% by weight or less from the viewpoint of easily obtaining good adhesive strength.
  • the monomer components constituting the acrylic polymer may be substantially composed of monofunctional monomers. That is, the monomer component does not need to contain a polyfunctional monomer.
  • biomass carbon ratio of the monomer component constituting the acrylic polymer may be, for example, 1% or more, suitably 10% or more, preferably 30% or more, and more preferably is 50% or more (for example, more than 50%), may be 70% or more, may be 80% or more, or may be 90% to 100%.
  • the method for obtaining the acrylic polymer is not particularly limited, and various polymerization methods known as methods for synthesizing acrylic polymers, such as solution polymerization, emulsion polymerization, bulk polymerization, suspension polymerization, and photopolymerization, can be used. may be adopted as appropriate.
  • a solution polymerization method can be preferably employed.
  • a monomer supply method when performing solution polymerization a batch charging method in which all monomer raw materials are supplied at once, a continuous supply (dropping) method, a divided supply (dropping) method, etc. can be appropriately adopted.
  • the polymerization temperature can be selected as appropriate depending on the type of monomer and solvent used, the type of polymerization initiator, etc., and is, for example, about 20°C to 170°C (typically about 40°C to 140°C). Can be done.
  • the solvent (polymerization solvent) used for solution polymerization can be appropriately selected from conventionally known organic solvents.
  • aromatic compounds such as toluene (typically aromatic hydrocarbons); acetate esters such as ethyl acetate; aliphatic or alicyclic hydrocarbons such as hexane and cyclohexane; 1,2-dichloroethane, etc. halogenated alkanes; lower alcohols such as isopropyl alcohol (for example, monohydric alcohols having 1 to 4 carbon atoms); ethers such as tert-butyl methyl ether; ketones such as methyl ethyl ketone; etc. Any one type of solvent or a mixed solvent of two or more types can be used.
  • the initiator used for polymerization can be appropriately selected from conventionally known polymerization initiators depending on the type of polymerization method.
  • one or more azo polymerization initiators such as 2,2'-azobisisobutyronitrile (AIBN) can be preferably used.
  • Other examples of polymerization initiators include persulfates such as potassium persulfate; peroxide initiators such as benzoyl peroxide (BPO) and hydrogen peroxide; substituted ethane initiators such as phenyl-substituted ethane; aromatic carbonyl compounds; and the like.
  • Still another example of the polymerization initiator is a redox initiator using a combination of a peroxide and a reducing agent.
  • Such polymerization initiators can be used alone or in combination of two or more.
  • the amount of the polymerization initiator used may be any normal amount, for example, approximately 0.005 to 1 part by weight (typically approximately 0.01 to 1 part by weight) per 100 parts by weight of all monomer components. degree).
  • the weight average molecular weight (Mw) of the acrylic polymer is not particularly limited, and may be, for example, about 300,000 or more and 5,000,000 or less.
  • the Mw of the acrylic polymer is usually preferably more than 500,000 (for example, 550,000 or more), more preferably 600,000 or more or more than 600,000 (for example, 650,000 or more). According to the acrylic polymer having such a Mw, it is easy to obtain a pressure-sensitive adhesive sheet that exhibits high levels of adhesive strength, oil resistance, and aqueous solvent resistance.
  • the Mw of the acrylic polymer may be 700,000 or more, 800,000 or more, 900,000 or more or more than 900,000, 950,000 or more, or 1 million or more.
  • the Mw of the acrylic polymer is usually approximately 3 million or less (for example, 2.5 million or less). Appropriate. In some embodiments, the Mw of the acrylic polymer is 2 million or less, from the viewpoint of increasing the adhesion between the adhesive layer and the adherend and easily suppressing the infiltration of oil and aqueous solvent into the interface between the two.
  • the number is 1.8 million or less, more preferably 1.8 million or less, 1.6 million or less, 1.5 million or less, 1.4 million or less, 1.3 million or less, 1.2 million or less, or 1.10 million or less. It may be less than 10,000, it may be less than 1 million, it may be less than 900,000, it may be less than 900,000, it may be less than 850,000, it may be less than 750,000.
  • the Mw of the acrylic polymer can be measured by gel permeation chromatography (GPC) and determined as a value in terms of standard polystyrene. Specifically, it can be determined by measuring under the following conditions using a GPC measurement device with the trade name "HLC-8220GPC" (manufactured by Tosoh Corporation). The same applies to the embodiments described below.
  • GPC gel permeation chromatography
  • the adhesive layer disclosed herein contains more than 10 parts by weight of a tackifier resin based on 100 parts by weight of the above-mentioned acrylic polymer, which is a polymer of monomer components containing n-HpA. By containing such an amount of tackifying resin, the adhesive strength can be effectively improved.
  • the content of the tackifying resin relative to 100 parts by weight of the acrylic polymer may be, for example, 12 parts by weight or more, 15 parts by weight or more, or 18 parts by weight or more. In some embodiments, from the viewpoint of obtaining higher usage effects, the content of the tackifying resin relative to 100 parts by weight of the acrylic polymer is suitably 18.5 parts by weight or more, and 20 parts by weight or more.
  • the amount is preferably 25 parts by weight or more, or 30 parts by weight or more.
  • Acrylic polymers containing n-HpA as a monomer unit have good compatibility with tackifying resins, so they can contain more tackifying resins while maintaining cohesive strength suitable for suppressing declines in oil resistance and aqueous solvent resistance. can be used to improve adhesion.
  • the content of the tackifying resin relative to 100 parts by weight of the acrylic polymer may be, for example, 100 parts by weight or less or 90 parts by weight or less, and from the viewpoint of better suppressing the decrease in adhesive strength due to contact with oil, 80 parts by weight or less may be used.
  • the amount is less than 60 parts by weight (for example, less than 55 parts by weight), more preferably less than 50 parts by weight, may be less than 45 parts by weight, may be less than 40 parts by weight, and may be less than 35 parts by weight.
  • the amount may be less than 30 parts by weight, or less than 25 parts by weight.
  • the tackifier resin is not particularly limited, and includes, for example, phenolic tackifier resin, rosin tackifier resin, terpene tackifier resin, hydrocarbon tackifier resin, epoxy tackifier resin, polyamide tackifier resin, Various tackifying resins such as elastomer-based tackifying resins and ketone-based tackifying resins can be used. Such tackifying resins can be used alone or in combination of two or more.
  • phenolic tackifying resins include terpene phenol resins, hydrogenated terpene phenol resins, alkyl phenol resins, rosin phenol resins, and the like.
  • Terpene phenol resin refers to a polymer containing terpene residues and phenol residues, and includes copolymers of terpenes and phenol compounds (terpene-phenol copolymer resins), and homopolymers or copolymers of terpenes. This concept includes both phenol-modified products (phenol-modified terpene resins).
  • terpenes constituting such terpene phenol resin include monoterpenes such as ⁇ -pinene, ⁇ -pinene, and limonene (including d-form, l-form, and d/l-form (dipentene)); can be mentioned.
  • the hydrogenated terpene phenol resin refers to a hydrogenated terpene phenol resin having a structure obtained by hydrogenating such a terpene phenol resin. Sometimes called hydrogenated terpene phenolic resin.
  • Alkylphenol resin is a resin (oil-based phenol resin) obtained from alkylphenol and formaldehyde. Examples of alkylphenol resins include novolak and resol types.
  • Rosin phenol resins are typically phenol-modified products of rosins or various rosin derivatives (including rosin esters, unsaturated fatty acid-modified rosins, and unsaturated fatty acid-modified rosin esters).
  • rosin phenolic resins include rosin phenolic resins obtained by adding phenol to rosins or the above-mentioned various rosin derivatives with an acid catalyst and thermally polymerizing them.
  • phenolic tackifier resins terpene phenol resins, hydrogenated terpene phenol resins and alkyl phenol resins are preferred, terpene phenol resins and hydrogenated terpene phenol resins are more preferred, and terpene phenol resins are especially preferred.
  • rosin-based tackifying resins examples include unmodified rosin (raw rosin) such as gum rosin, wood rosin, and tall oil rosin; Examples include additive rosin, disproportionated rosin, polymerized rosin, other chemically modified rosin, etc. (the same applies hereinafter); and other various rosin derivatives.
  • unmodified rosin raw rosin
  • examples include additive rosin, disproportionated rosin, polymerized rosin, other chemically modified rosin, etc. (the same applies hereinafter); and other various rosin derivatives.
  • examples of the above-mentioned rosin derivatives include rosins such as those obtained by esterifying unmodified rosin with alcohols (i.e., esterified products of rosin), and those obtained by esterifying modified rosin with alcohols (i.e., esterified products of modified rosin).
  • Esters Unsaturated fatty acid-modified rosins, which are unmodified rosin or modified rosin modified with unsaturated fatty acids; Unsaturated fatty acid-modified rosin esters, which are rosin esters modified with unsaturated fatty acids; Unmodified rosin, modified rosin, unsaturated Rosin alcohols obtained by reducing the carboxyl group in fatty acid-modified rosins or unsaturated fatty acid-modified rosin esters; metal salts of rosins (especially rosin esters) such as unmodified rosin, modified rosin, and various rosin derivatives; etc. Can be mentioned. Among them, rosin ester is preferred.
  • rosin esters include esters of unmodified rosin or modified rosin (hydrogenated rosin, disproportionated rosin, polymerized rosin, etc.), such as methyl ester, triethylene glycol ester, glycerin ester. , pentaerythritol ester and the like.
  • terpene-based tackifying resins include polymers of terpenes (eg, monoterpenes) such as ⁇ -pinene, ⁇ -pinene, d-limonene, l-limonene, and dipentene. It may be a homopolymer of one type of terpene, or a copolymer of two or more types of terpene. Examples of the homopolymer of one type of terpene include ⁇ -pinene polymer, ⁇ -pinene polymer, dipentene polymer, and the like.
  • hydrocarbon-based tackifying resins examples include aliphatic (C5-based) petroleum resins, aromatic (C9-based) petroleum resins, aliphatic/aromatic copolymerized (C5/C9-based) petroleum resins, and Hydrogenated substances (e.g., alicyclic petroleum resins obtained by hydrogenating aromatic petroleum resins), various modified products thereof (e.g., maleic anhydride modified products), coumaron-based resins, coumaron-indene-based resins Examples include various hydrocarbon resins such as.
  • a phenolic tackifying resin as the tackifying resin.
  • a phenolic tackifying resin it is possible to desirably improve the adhesive strength while suppressing an increase in the degree of swelling.
  • terpene phenol resins are preferred.
  • the tackifying resin one or more types of phenolic tackifying resin may be used alone, or a phenolic tackifying resin and another tackifying resin (for example, a rosin tackifying resin) may be used in combination. You can.
  • the proportion of the phenolic tackifying resin (for example, terpene phenol resin) in the entire tackifying resin contained in the adhesive layer can be approximately 35% by weight or more, for example, to suitably enhance the effect of using the phenolic tackifying resin.
  • the content is preferably more than about 50% by weight, may be about 70% by weight or more, and may be about 80% by weight or more.
  • the technology disclosed herein is preferably in an embodiment in which substantially all of the tackifier resin (for example, approximately 97% by weight or more, or 99% by weight or more, and may be 100% by weight) is a phenolic tackifier resin. can be implemented.
  • the content of the terpene phenol resin may be, for example, 1 part by weight or more, 3 parts by weight or more, 5 parts by weight or more, based on 100 parts by weight of the acrylic polymer.
  • the amount may be at least 7 parts by weight, at least 9 parts by weight, at least 12 parts by weight, at least 15 parts by weight, or at least 18 parts by weight.
  • the content of the terpene phenol resin relative to 100 parts by weight of the acrylic polymer is suitably 18.5 parts by weight or more, and 20 parts by weight or more.
  • the amount is preferably 25 parts by weight or more.
  • the content of the terpene phenol resin relative to 100 parts by weight of the acrylic polymer is suitably 80 parts by weight or less, preferably 60 parts by weight or less (e.g. 55 parts by weight or less), more preferably 50 parts by weight or less, may be 45 parts by weight or less, may be 40 parts by weight or less, may be 35 parts by weight or less, may be 30 parts by weight or less, may be 25 parts by weight or less.
  • the content of the terpene phenol resin being X parts by weight or less based on 100 parts by weight of the acrylic polymer means that the adhesive layer does not contain the terpene phenol resin and that the terpene phenol resin is not contained in the acrylic polymer.
  • the term is used to include both the inclusion of X parts by weight or less per 100 parts by weight.
  • the content of the terpene phenol resin in the adhesive layer may be 10 parts by weight or less, 5 parts by weight or less, 3 parts by weight or less, or 1 part by weight based on 100 parts by weight of the acrylic polymer. part or less (for example, 0 to 0.1 part by weight).
  • the content of the tackifying resin other than the phenolic tackifying resin (non-phenolic tackifying resin, e.g. rosin tackifying resin) in the adhesive layer is For example, it is appropriate to use 40 parts by weight or less with respect to 100 parts by weight of the polymer. Thereby, the effect of including the phenol-based tackifying resin can be easily exhibited.
  • the amount of non-phenolic tackifying resin used is preferably about 20 parts by weight or less (e.g., less than 20 parts by weight), more preferably about 15 parts by weight or less, based on 100 parts by weight of the acrylic polymer. The amount may be approximately 10 parts by weight or less, or approximately 5 parts by weight or less.
  • a tackifying resin T L having a softening point of less than 150° C. is used as the tackifying resin from the viewpoint of adhesion to the adherend.
  • the lower limit of the softening point of the tackifier resin T L is not particularly limited.
  • the softening point of the tackifier resin T L is suitably about 60° C. or higher, for example, about 80° C. or higher, and about 90° C. or higher, from the viewpoint of exhibiting appropriate cohesive force.
  • the temperature may be 100°C or higher, or approximately 100°C or higher.
  • the tackifier resin T L one type suitably selected from among the tackifier resins exemplified above having a softening point of less than 150°C can be used alone or in combination of two or more types.
  • the tackifying resin T L preferably comprises a phenolic tackifying resin.
  • the tackifying resin T L may contain only one type of phenolic tackifying resin, or may contain two or more types of phenolic tackifying resin.
  • the tackifying resin T L may include a combination of a phenolic tackifying resin and a non-phenolic tackifying resin.
  • the non-phenolic tackifying resin may be one or more selected from among the tackifying resins listed above that are other than phenolic tackifying resins and have a softening point of less than 150°C. Can be used in combination.
  • the proportion of the phenolic tackifier resin in the entire tackifier resin T L can be, for example, more than about 50% by weight, may be about 65% by weight or more, and may be about 75% by weight or more. Good too.
  • the technology disclosed herein is an embodiment in which substantially all of the tackifier resin T L (for example, approximately 97% by weight or more, or 99% by weight or more, and may be 100% by weight) is a phenolic tackifier resin. It can be preferably carried out.
  • the content of the tackifying resin T L (if two or more types of tackifying resin T L are included, the total amount thereof) is not particularly limited, but may be 80 parts by weight or less based on 100 parts by weight of the acrylic polymer. From the viewpoint of adhesion to the adherend, etc., the amount is preferably 60 parts by weight or less (for example, 55 parts by weight or less), more preferably 50 parts by weight or less, and may be 45 parts by weight or less, and 40 parts by weight. It may be less than 35 parts by weight, it may be less than 30 parts by weight, and it may be less than 25 parts by weight.
  • the amount of the tackifying resin T L to be used per 100 parts by weight of the acrylic polymer may be, for example, 5 parts by weight or more, 7 parts by weight or more, 9 parts by weight or more, 12 parts by weight or more, 15 parts by weight or more. or more than 18 parts by weight.
  • the amount of the tackifying resin T L to be used per 100 parts by weight of the acrylic polymer is, for example, 18.5 parts by weight or more, and 20 parts by weight or more. The amount is preferably 25 parts by weight or more.
  • the adhesive layer may include a combination of a tackifying resin T L and a tackifying resin T H having a softening point of 150° C. or higher (eg, 150° C. to 200° C.).
  • a tackifying resin T H having a softening point of 150° C. or higher (eg, 150° C. to 200° C.).
  • the tackifier resin T H one kind or a combination of two or more kinds of tackifier resins having a softening point of 150° C. or more among the tackifier resins exemplified above can be used.
  • the softening point of the tackifier resin in this specification is defined as a value measured based on the softening point test method (ring and ball method) specified in JIS K5902 and JIS K2207. Specifically, the sample is melted as quickly as possible at the lowest possible temperature, and the sample is carefully filled into a ring placed on a flat metal plate, taking care not to form bubbles. After it has cooled down, use a slightly heated knife to cut off the raised part from the plane including the top of the ring.
  • a supporter (ring stand) is placed in a glass container (heating bath) with a diameter of 85 mm or more and a height of 127 mm or more, and glycerin is poured into the container to a depth of 90 mm or more.
  • the steel ball (diameter 9.5 mm, weight 3.5 g) and the ring filled with the sample were immersed in glycerin without coming into contact with each other, and the temperature of the glycerin was maintained at 20°C plus or minus 5°C for 15 minutes. .
  • a steel ball is then placed in the center of the surface of the sample in the ring and placed in position on the support.
  • thermometer place a thermometer, set the center of the mercury bulb of the thermometer at the same height as the center of the ring, and heat the container.
  • the flame of the Bunsen burner used for heating should be halfway between the center of the bottom of the container and the edge to ensure even heating. Note that the rate at which the bath temperature increases after heating starts and reaches 40°C must be 5.0 plus or minus 0.5°C per minute.
  • the sample gradually softens and flows down from the ring, and the temperature at which it finally touches the bottom plate is read, and this is taken as the softening point.
  • the softening point is measured at two or more points at the same time, and the average value is used.
  • the tackifier resin T L accounts for more than 50% by weight of the total amount of tackifier resins included in the adhesive layer. Thereby, the effect of containing the tackifying resin TL tends to be effectively expressed.
  • the proportion of the tackifying resin T L in the total amount of the tackifying resin contained in the adhesive layer is preferably 60% by weight or more, more preferably The content is 70% by weight or more, more preferably 80% by weight or more, particularly preferably 90% by weight or more, may be 95% by weight or more, or may be 98% by weight or more.
  • the tackifier resin contained in the adhesive layer consists essentially only of tackifier resin TL . In this embodiment, the proportion of the tackifying resin T L in the total amount of tackifying resin contained in the adhesive layer is in the range of 99 to 100% by weight.
  • the tackifying resin may include a tackifying resin having a hydroxyl value of 40 mgKOH/g or more (for example, more than 40 mgKOH/g, preferably 45 mgKOH/g or more, more preferably 50 mgKOH/g or more).
  • the tackifier resin having such a hydroxyl value may be referred to as a "high hydroxyl value resin”.
  • Acrylic polymers containing n-HpA as a monomer unit have good compatibility with such high hydroxyl value resins, so using such high hydroxyl value resins, it is possible to achieve a good balance between oil resistance and aqueous solvent resistance while increasing adhesive strength. can be increased.
  • the hydroxyl value of the high hydroxyl value resin may be 60 mgKOH/g or more, 80 mgKOH/g or more, 90 mgKOH/g or more, or 100 mgKOH/g or more.
  • the upper limit of the hydroxyl value of the high hydroxyl value resin is not particularly limited, and may be, for example, about 200 mgKOH/g or less, about 160 mgKOH/g or less, or about 140 mgKOH/g or less.
  • the hydroxyl value of the high hydroxyl value resin is preferably about 125 mgKOH/g or less, may be about 115 mgKOH/g or less, and may be about 90 mgKOH/g or less. But that's fine.
  • the high hydroxyl value resin one type appropriately selected from among the tackifier resins exemplified above having a hydroxyl value corresponding to the high hydroxyl value resin can be used alone or in combination of two or more types.
  • the high hydroxyl resin preferably comprises a phenolic tackifying resin (eg, a terpene phenolic resin).
  • the high hydroxyl value resin may contain one type of phenolic tackifying resin alone, or may contain a combination of two or more types of phenolic tackifying resin.
  • the high hydroxyl value resin may be the above-mentioned tackifier resin T L or tackifier resin T H.
  • a high hydroxyl value resin that is the tackifier resin T L may be preferably employed. According to the high hydroxyl value resin which is the tackifying resin T L , it is possible to suppress a decrease in oil resistance and aqueous solvent resistance, and to improve the adhesive force by including a larger amount of the tackifying resin.
  • a high hydroxyl value resin for example, a high hydroxyl value resin with a hydroxyl value of more than 40 mgKOH/g, preferably 45 mgKOH/g or more, more preferably 50 mgKOH/g or more
  • a high hydroxyl value resin is included in the adhesive layer.
  • it accounts for more than 30% by weight of the total amount of resin, more preferably more than 50% by weight. This can preferably achieve the effect of increasing adhesive strength while achieving both oil resistance and aqueous solvent resistance in a well-balanced manner.
  • the proportion of the high hydroxyl value resin in the total amount of tackifier resin contained in the adhesive layer is preferably 60% by weight or more, from the viewpoint of facilitating the use of the high hydroxyl value resin.
  • the tackifying resin contained in the adhesive layer consists essentially only of a high hydroxyl value resin.
  • the proportion of the high hydroxyl value resin in the total amount of tackifier resin contained in the adhesive layer is in the range of 99 to 100% by weight.
  • the tackifying resin may include a tackifying resin having a hydroxyl value of less than 40 mgKOH/g (for example, less than 30 mgKOH/g).
  • the tackifying resin having such a hydroxyl value may be referred to as a "low hydroxyl value resin”.
  • the hydroxyl value of the low hydroxyl value resin may be approximately 20 mgKOH/g or less, approximately 15 mgKOH/g or less, or approximately 10 mgKOH/g or less.
  • the lower limit of the hydroxyl value of the low hydroxyl value resin is not particularly limited, and may be substantially 0 mgKOH/g.
  • a low hydroxyl value resin is preferably used in combination with a high hydroxyl value resin and can be useful for adjusting adhesive properties and the like.
  • the technology disclosed herein may be implemented in an embodiment in which only a low hydroxyl value resin is used as the tackifying resin.
  • the low hydroxyl value resin one type suitably selected from among the tackifier resins exemplified above having a hydroxyl value corresponding to the low hydroxyl value resin can be used alone or in combination of two or more types.
  • the low hydroxyl value resin preferably includes a rosin-based tackifying resin.
  • the hydroxyl value resin may contain one type of rosin-based tackifier resin alone, or may contain a combination of two or more types of rosin-based tackifier resin.
  • the low hydroxyl value resin may be the above-mentioned tackifier resin T L or tackifier resin T H.
  • a low hydroxyl value resin that is the tackifier resin T L may be preferably employed.
  • the amount used is, for example, 1 part by weight per 100 parts by weight of the acrylic polymer.
  • the amount may be at least 3 parts by weight, at least 5 parts by weight, at least 7 parts by weight, and at least 9 parts by weight.
  • the amount of the low hydroxyl value resin to be used per 100 parts by weight of the acrylic polymer is usually 50 parts by weight or less, may be 40 parts by weight or less, may be 30 parts by weight or less, and may be 20 parts by weight or less. It may be 15 parts by weight or less, 10 parts by weight or less, 8 parts by weight or less, 4 parts by weight or less, or 2 parts by weight or less. It is not necessary to use a low hydroxyl value resin.
  • a value measured by the potentiometric titration method specified in JIS K0070:1992 can be adopted.
  • the specific measurement method is as shown below.
  • [Method for measuring hydroxyl value] 1.
  • Reagent (1) As the acetylation reagent, take about 12.5 g (about 11.8 mL) of acetic anhydride, add pyridine to make a total volume of 50 mL, and stir thoroughly. Alternatively, take about 25 g (about 23.5 mL) of acetic anhydride, add pyridine to make a total volume of 100 mL, stir thoroughly, and use.
  • (2) A 0.5 mol/L potassium hydroxide ethanol solution is used as the measurement reagent.
  • a tackifying resin contained in the adhesive layer disclosed herein from the viewpoint of improving the biomass carbon ratio of the adhesive layer, a tackifying resin derived from plants (vegetable tackifying resin) can preferably act.
  • the vegetable tackifier resin include the above-mentioned rosin-based tackifier resin and terpene-based tackifier resin.
  • the vegetable tackifying resins can be used alone or in combination of two or more.
  • the proportion of the vegetable tackifying resin in the total amount of the tackifying resin is preferably 30% by weight or more (for example, 50% by weight or more, typically 80% by weight or more).
  • the proportion of vegetable tackifying resin in the total amount of tackifying resin is 90% by weight or more (eg, 95% by weight or more, typically 99-100% by weight).
  • the technology disclosed herein can be preferably implemented in an embodiment that does not substantially contain tackifying resins other than vegetable tackifying resins.
  • the total content of the acrylic polymer and tackifying resin in the adhesive layer is appropriately set and limited to a specific range so that the effects of the technology disclosed herein are exhibited. It's not something you can do.
  • the total amount (total amount) of the acrylic polymer and tackifier resin contained in the adhesive layer is more than 50% by weight from the viewpoint of preferably exhibiting the effects of the technology disclosed herein. is appropriate, preferably about 70% by weight or more, more preferably about 90% by weight or more, even more preferably 95% by weight or more (for example, 95% by weight or more and 100% by weight or less, or less than 100% by weight), and 97% by weight. % or more.
  • the adhesive composition used to form the adhesive layer may contain a crosslinking agent as necessary.
  • the type of crosslinking agent is not particularly limited, and examples include epoxy crosslinking agents, isocyanate crosslinking agents, oxazoline crosslinking agents, aziridine crosslinking agents, melamine crosslinking agents, peroxide crosslinking agents, urea crosslinking agents, and metals. Examples include alkoxide crosslinking agents, metal chelate crosslinking agents, metal salt crosslinking agents, carbodiimide crosslinking agents, hydrazine crosslinking agents, amine crosslinking agents, and silane coupling agents.
  • crosslinking agent can be used alone or two or more types can be used in combination. Among these, epoxy crosslinking agents, isocyanate crosslinking agents, oxazoline crosslinking agents, aziridine crosslinking agents, and melamine crosslinking agents are preferred, and epoxy crosslinking agents and isocyanate crosslinking agents are more preferred.
  • a cohesion degree of 100 or less can be preferably achieved.
  • the adhesive layer in the technology disclosed herein may contain the crosslinking agent in a form after a crosslinking reaction, a form before a crosslinking reaction, a partially crosslinked form, an intermediate or composite form thereof, etc. May contain.
  • the crosslinking agent is typically contained in the adhesive layer exclusively in the form after crosslinking reaction.
  • epoxy crosslinking agent any compound having two or more epoxy groups in one molecule can be used without particular limitation. Epoxy crosslinking agents having 3 to 5 epoxy groups in one molecule are preferred. The epoxy crosslinking agents can be used alone or in combination of two or more.
  • epoxy crosslinking agents include N,N,N',N'-tetraglycidyl-m-xylene diamine, 1,3-bis(N,N-diglycidylaminomethyl ) cyclohexane, 1,6-hexanediol diglycidyl ether, polyethylene glycol diglycidyl ether, polyglycerol polyglycidyl ether and the like.
  • epoxy crosslinking agents include Mitsubishi Gas Chemical's product names “TETRAD-C” and “TETRAD-X”, DIC's product name “Epicron CR-5L”, and Nagase ChemteX's product name Examples include the product name “Denacol EX-512” manufactured by Nissan Chemical Industries, Ltd. and the product name "TEPIC-G” manufactured by Nissan Chemical Industries, Ltd.
  • the amount of the epoxy crosslinking agent used is not particularly limited.
  • the amount of the epoxy crosslinking agent used may be, for example, more than 0 parts by weight and no more than about 1 part by weight (typically about 0.001 to 1 part by weight) per 100 parts by weight of the acrylic polymer. can. From the viewpoint of suitably exhibiting the effect of improving cohesive force, it is appropriate that the amount of the epoxy crosslinking agent used is approximately 0.005 parts by weight or more, and approximately 0.01 parts by weight, based on 100 parts by weight of the acrylic polymer. It is preferably at least 0.01 part by weight, or at least 0.015 part by weight, and approximately at least 0.02 part by weight (for example, at least 0.02 part by weight, or at least 0.025 part by weight). More preferred.
  • the amount of the epoxy crosslinking agent used is approximately 0.5 parts by weight or less per 100 parts by weight of the acrylic polymer, and approximately 0.2 parts by weight. It is preferably at most 0.1 parts by weight, more preferably at most 0.1 parts by weight (for example, less than 0.1 parts by weight), it may be at most 0.07 parts by weight, it may be at most 0.05 parts by weight, The amount may be 0.04 part by weight or less (for example, less than 0.04 part by weight), less than 0.035 part by weight, or less than 0.03 part by weight.
  • polyfunctional isocyanates referring to compounds having an average of two or more isocyanate groups per molecule, including those having an isocyanurate structure
  • the isocyanate crosslinking agents can be used alone or in combination of two or more.
  • polyfunctional isocyanates include aliphatic polyisocyanates, alicyclic polyisocyanates, aromatic polyisocyanates, and the like.
  • aliphatic polyisocyanates include 1,2-ethylene diisocyanate; tetramethylene diisocyanates such as 1,2-tetramethylene diisocyanate, 1,3-tetramethylene diisocyanate, and 1,4-tetramethylene diisocyanate; 1,2-tetramethylene diisocyanate; - hexamethylene diisocyanate such as hexamethylene diisocyanate, 1,3-hexamethylene diisocyanate, 1,4-hexamethylene diisocyanate, 1,5-hexamethylene diisocyanate, 1,6-hexamethylene diisocyanate, 2,5-hexamethylene diisocyanate; Examples include 2-methyl-1,5-pentane diisocyanate, 3-methyl-1,5-pentane diisocyanate, ly
  • alicyclic polyisocyanates include isophorone diisocyanate; cyclohexyl diisocyanates such as 1,2-cyclohexyl diisocyanate, 1,3-cyclohexyl diisocyanate, and 1,4-cyclohexyl diisocyanate; 1,2-cyclopentyl diisocyanate, and 1,3-cyclohexyl diisocyanate; -Cyclopentyl diisocyanates such as cyclopentyl diisocyanate; hydrogenated xylylene diisocyanate, hydrogenated tolylene diisocyanate, hydrogenated diphenylmethane diisocyanate, hydrogenated tetramethylxylene diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, and the like.
  • aromatic polyisocyanates include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, and 2,2'-diphenylmethane diisocyanate.
  • polyfunctional isocyanates examples include polyfunctional isocyanates having an average of three or more isocyanate groups per molecule.
  • Such trifunctional or higher functional isocyanates are polymers (typically dimers or trimers) of bifunctional or trifunctional or higher functional isocyanates, derivatives (for example, a combination of a polyhydric alcohol and two or more molecules of polyfunctional isocyanate). addition reaction products), polymers, etc.
  • dimers and trimers of diphenylmethane diisocyanate dimers and trimers of diphenylmethane diisocyanate, isocyanurates of hexamethylene diisocyanate (trimeric adducts of isocyanurate structures), reaction products of trimethylolpropane and tolylene diisocyanate, and products of the reaction between trimethylolpropane and hexamethylene diisocyanate.
  • polyfunctional isocyanates such as reaction products with methylene diisocyanate, polymethylene polyphenylisocyanate, polyether polyisocyanate, and polyester polyisocyanate.
  • the amount of the isocyanate crosslinking agent used is not particularly limited, and can be approximately 0.1 parts by weight or more, for example, based on 100 parts by weight of the acrylic polymer. From the viewpoint of coexistence of adhesive strength, oil resistance, and aqueous solvent resistance, the amount of the isocyanate crosslinking agent to be used with respect to 100 parts by weight of the acrylic polymer can be, for example, 0.5 parts by weight or more, and 1.0 parts by weight. or more, advantageously 1.5 parts by weight or more, preferably 2.0 parts by weight or more, more preferably more than 2.5 parts by weight, and 2.8 parts by weight or more. It may be 3.0 parts by weight or more, or 3.5 parts by weight or more.
  • the amount of the isocyanate crosslinking agent used is suitably 10 parts by weight or less per 100 parts by weight of the acrylic system, preferably less than 8.0 parts by weight, more preferably less than 7.0 parts by weight. , more preferably less than 6.0 parts by weight, and may be less than 5.0 parts by weight or less than 4.5 parts by weight.
  • an epoxy crosslinking agent and at least one crosslinking agent having a different type of crosslinkable functional group from the epoxy crosslinking agent are used in combination.
  • a crosslinking agent other than an epoxy crosslinking agent that is, a crosslinking agent having a different type of crosslinkable reactive group from an epoxy crosslinking agent; hereinafter also referred to as a "non-epoxy crosslinking agent"
  • an epoxy crosslinking agent By using it in combination with an epoxy crosslinking agent, it is possible to suitably achieve both adhesion to different materials and high holding power.
  • non-epoxy crosslinking agent that can be used in combination with the epoxy crosslinking agent is not particularly limited, and can be appropriately selected from the above-mentioned crosslinking agents.
  • the non-epoxy crosslinking agents can be used alone or in combination of two or more.
  • an isocyanate crosslinking agent can be employed as the non-epoxy crosslinking agent.
  • an epoxy crosslinking agent and an isocyanate crosslinking agent in combination, better adhesive properties can be achieved.
  • the relationship between the content of the epoxy crosslinking agent and the content of the non-epoxy crosslinking agent (preferably an isocyanate crosslinking agent) is not particularly limited.
  • the content of the epoxy crosslinking agent can be, for example, about 1/10 or less of the content of the non-epoxy crosslinking agent (preferably an isocyanate crosslinking agent).
  • the content of the epoxy crosslinking agent is approximately 1/30 or less of the content of the non-epoxy crosslinking agent, It is preferably about 1/50 or less (for example, about 1/60 or less), more preferably about 1/75 or less, and may be about 1/90 or less.
  • the content of the epoxy crosslinking agent is usually adjusted to It is appropriate to set the content to about 1/1000 or more, for example about 1/500 or more, preferably about 1/300 or more, more preferably 1/180 or more (for example, 1/150 or more) of the content of the system crosslinking agent. More preferably, it is 1/120 or more.
  • the total amount of the crosslinking agent used is not particularly limited, and for example, approximately 0.005 parts by weight or more (for example, 0.01 parts by weight or more, typically 0.1 parts by weight or more) based on 100 parts by weight of the acrylic polymer.
  • the amount can be selected from a range of about 10 parts by weight or less (for example, about 8 parts by weight or less, preferably about 5 parts by weight or less).
  • the adhesive composition may contain a leveling agent, a crosslinking aid, a plasticizer, a softener, a filler, a coloring agent (pigment, dye, etc.), an antistatic agent, and an antiaging agent, as necessary.
  • a leveling agent e.g., a plasticizer, a softener, a filler, a coloring agent (pigment, dye, etc.), an antistatic agent, and an antiaging agent, as necessary.
  • ultraviolet absorbers, antioxidants, light stabilizers, and other additives commonly used in the adhesive field e.g., ultraviolet absorbers, antioxidants, light stabilizers, and other additives commonly used in the adhesive field.
  • conventionally known ones can be used in a conventional manner, and since they do not particularly characterize the present invention, detailed explanations will be omitted.
  • the adhesive layer in the technology disclosed herein has a swelling degree of 100 or less with respect to ethyl acetate.
  • an acrylic polymer containing n-HpA as a monomer component and setting the content of the tackifier resin to more than 10 parts by weight with respect to 100 parts by weight of the acrylic polymer under the condition that the degree of swelling is 100 or less, the adhesive strength can be improved. It is possible to effectively increase the adhesive force and suppress a decrease in adhesive strength due to contact with oil or aqueous solvents. This makes it possible to realize a pressure-sensitive adhesive sheet that exhibits high levels of adhesive strength, oil resistance, and aqueous solvent resistance.
  • the swelling degree of the adhesive layer is preferably 90 or less, more preferably 80 or less, may be 75 or less, may be 70 or less, and may be 65 or less, from the viewpoint of improving oil resistance. It may be 60 or less (for example, less than 60).
  • the lower limit of the degree of swelling is not particularly limited, and may be, for example, 10 or more.
  • the degree of swelling of the adhesive layer is suitably 30 or more, preferably 35 or more, and more preferably 40 or more. Preferably, it may be 45 or more (for example, more than 45), or 50 or more.
  • the degree of swelling of the adhesive layer is measured by the method described in Examples below.
  • the degree of swelling can be adjusted by adjusting the monomer composition and Mw of the acrylic polymer, and the composition of the adhesive such as the tackifying resin and the crosslinking agent.
  • the adhesive layer (layer consisting of an adhesive) disclosed herein is formed from a water-based adhesive composition, a solvent-based adhesive composition, a hot-melt adhesive composition, or an active energy ray-curable adhesive composition. It may be an adhesive layer.
  • the aqueous adhesive composition refers to an adhesive composition containing an adhesive (adhesive layer forming component) in a water-based solvent (aqueous solvent), and is typically a water-based adhesive composition. This includes what is called a type adhesive composition (a composition in which at least a portion of an adhesive is dispersed in water).
  • a solvent-based adhesive composition refers to an adhesive composition containing an adhesive in an organic solvent.
  • organic solvent contained in the solvent-based adhesive composition one or more of the organic solvents (toluene, ethyl acetate, etc.) that can be used in the above-mentioned solution polymerization can be used without particular limitation.
  • the technology disclosed herein can be preferably implemented in an embodiment including an adhesive layer formed from a solvent-based adhesive composition from the viewpoint of adhesive properties and the like.
  • the adhesive layer disclosed herein can be formed by a conventionally known method.
  • a method can be adopted in which a pressure-sensitive adhesive layer is formed by applying a pressure-sensitive adhesive composition to a surface having peelability (peelability surface) or a non-peelability surface and drying it.
  • a method directly method of forming an adhesive layer by directly applying (typically coating) an adhesive composition to the base material and drying is adopted.
  • a method transfer method in which an adhesive composition is applied to a surface that has releasability (release surface) and dried to form an adhesive layer on the surface, and the adhesive layer is transferred to a base material. may be adopted.
  • the transfer method is preferred.
  • the release surface the surface of a release liner, the back surface of a release-treated base material, etc. can be used.
  • the adhesive layer disclosed herein is typically formed continuously, it is not limited to this form, and may be formed, for example, in a regular or random pattern such as dots or stripes. It may also be a formed adhesive layer.
  • the adhesive composition can be applied using a conventionally known coater such as a gravure roll coater, die coater, or bar coater. Alternatively, the adhesive composition may be applied by impregnation, curtain coating, or the like. From the viewpoint of promoting crosslinking reaction, improving production efficiency, etc., it is preferable to dry the adhesive composition under heating.
  • the drying temperature can be, for example, about 40 to 150°C, and usually preferably about 60 to 130°C.
  • aging may be performed for the purpose of adjusting component migration within the pressure-sensitive adhesive layer, progressing the crosslinking reaction, alleviating distortion that may exist within the pressure-sensitive adhesive layer, and the like.
  • the thickness of the adhesive layer is not particularly limited, and a configuration having an adhesive layer having an appropriate thickness in the range of, for example, 0.1 ⁇ m to 500 ⁇ m may be adopted depending on the use and purpose of use.
  • the thickness of the adhesive layer is suitably about 100 ⁇ m or less, preferably about 70 ⁇ m or less, more preferably about 50 ⁇ m or less. , more preferably about 35 ⁇ m or less.
  • the thickness of the adhesive layer may be approximately 30 ⁇ m or less (for example, less than 30 ⁇ m), approximately 25 ⁇ m or less (for example, less than 25 ⁇ m), or approximately 22 ⁇ m or less, It may be approximately 20 ⁇ m or less (for example, less than 20 ⁇ m).
  • An adhesive layer with a limited thickness can meet the demands for thinning and weight reduction. Additionally, in general, as the thickness of the adhesive layer decreases, the adhesive strength tends to decrease, and the adhesion to the adherend also decreases, making it easier for oil and aqueous solvents to penetrate into the interface.
  • the lower limit of the thickness of the adhesive layer is suitably about 0.5 ⁇ m or more, from the viewpoint of adhesion to the adherend, it may be about 1 ⁇ m or more, and it may be about 3 ⁇ m or more.
  • the thickness of the adhesive layer may be greater than 20 ⁇ m, greater than or equal to 24 ⁇ m, or greater than or equal to 27 ⁇ m.
  • the pressure-sensitive adhesive sheet disclosed herein may be a pressure-sensitive adhesive sheet having pressure-sensitive adhesive layers having the above-mentioned thickness on both sides of a base material.
  • the first adhesive layer and the second adhesive layer have the same thickness. They may have different thicknesses.
  • the pressure-sensitive adhesive layer preferably has a surface free energy ⁇ of less than 40 mJ/m 2 .
  • ⁇ d , ⁇ p and ⁇ h in the above formula represent a dispersion component, a polar component and a hydrogen bond component of surface free energy, respectively.
  • the surface free energy ⁇ of the adhesive layer is determined by using water, diiodomethane, and 1-bromonaphthalene as probe liquids, and using the Kitazaki-Hata formula (Japan Adhesive Association Journal, Vol. 8, No.
  • the contact angle can be measured using a commercially available contact angle meter.
  • the product name "CA-X” manufactured by Kyowa Interface Science Co., Ltd. can be used as the contact angle meter.
  • a droplet method is used for the measurement, and the contact angle is measured from the shape of the droplet 1500 ms after the droplet has landed. A similar method is also adopted in the embodiments described below.
  • the surface free energy ⁇ of the adhesive layer decreases, the wettability of the adhesive layer to the adherend improves, and the adhesion at the interface (adhesive interface) between the adhesive layer and the adherend tends to increase. .
  • the adhesion of the adhesive interface in this way, it is possible to suppress the infiltration of oil and aqueous solvent from the outer edge of the pressure-sensitive adhesive sheet to the adhesive interface. Therefore, it is preferable to increase the adhesion of the interface between the adhesive layer and the adherend from the viewpoint of suppressing a decrease in adhesive strength due to contact with oil or an aqueous solvent. It is preferable to increase the adhesion of the interface between the adhesive layer and the adherend from the viewpoint of suppressing a decrease in adhesive strength due to contact with oil or an aqueous solvent.
  • the surface free energy ⁇ of the adhesive layer is preferably about 35 mJ/m 2 or less, more preferably about 30 mJ/m 2 or less, and 27 mJ/m 2 or less. m 2 or less, 25 mJ/m 2 or less, or 20 mJ/m 2 or less.
  • the lower limit of the surface free energy ⁇ of the adhesive layer is not particularly limited, but is usually about 7 mJ/m 2 or more, preferably about 10 mJ/m 2 or more.
  • the surface free energy ⁇ of the adhesive layer may be 15 mJ/m 2 or more, or 20 mJ/m 2 or more.
  • the surface free energy ⁇ of the adhesive layer can be adjusted by, for example, the composition of the monomer components constituting the acrylic polymer, the type and amount of the tackifying resin used, and the like.
  • the gel fraction of the adhesive layer disclosed herein is not particularly limited, and may be, for example, within the range of 20% to 80% (by weight). By increasing the gel fraction of the adhesive layer within an appropriate range, it is possible to impart cohesive properties to the adhesive layer and suppress a decrease in adhesive strength due to contact with oil or an aqueous solvent.
  • the gel fraction of the adhesive layer is suitably greater than 30%, advantageously greater than 40%, may be greater than 45%, may be greater than 50%, and may be greater than 55%. % or more, 60% or more, for example, more than 63%.
  • the gel fraction of the adhesive layer is preferably 75% or less, and preferably 70% or less (for example, less than 70%). More preferably, it is 68% or less, and may be 66% by weight or less.
  • the above gel fraction is measured by the following method. That is, approximately 0.1 g of an adhesive sample (weight Wg 1 ) was wrapped in a purse-like shape with a porous polytetrafluoroethylene membrane (weight Wg 2 ) with an average pore diameter of 0.2 ⁇ m, and the opening was wrapped with an octopus thread (weight Wg 3 ). tie up
  • the above-mentioned porous polytetrafluoroethylene (PTFE) membrane is available from Nitto Denko under the trade name "Nitoflon (registered trademark) NTF1122" (average pore diameter 0.2 ⁇ m, porosity 75%, thickness 85 ⁇ m) or its equivalent. use the product.
  • the adhesive layer may include a biomass-derived material, and the biomass carbon ratio may be greater than or equal to a predetermined value.
  • the biomass carbon ratio of the adhesive layer is, for example, 1% or more, and may be 10% or more, preferably 30% or more, and more preferably 50% or more.
  • a high biomass carbon ratio in the adhesive means that less fossil resource-based materials, such as petroleum, are used. From this point of view, the higher the biomass carbon ratio of the adhesive, the more preferable.
  • the biomass carbon ratio of the adhesive layer may be 55% or more, 60% or more, 70% or more, 75% or more, 80% or more, or more than 80%. good.
  • the upper limit of the biomass carbon ratio is 100% by definition, and may be 99% or less, and from the viewpoint of material availability, it may be 95% or less, or 90% or less. In some embodiments, from the viewpoint of facilitating good adhesive performance, the biomass carbon ratio of the adhesive layer may be, for example, 90% or less, 85% or less, or 80% or less.
  • the base material that supports (backs) the adhesive layer may be a resin film, paper, cloth, or rubber. Sheets, foam sheets, metal foils, composites thereof, etc. can be used.
  • resin films include polyolefin films such as polyethylene (PE), polypropylene (PP), and ethylene-propylene copolymers; polyester films such as polyethylene terephthalate (PET); vinyl chloride resin films; vinyl acetate resin films; polyimide Examples include resin film; polyamide resin film; fluororesin film; cellophane, and the like.
  • Examples of paper include Japanese paper, kraft paper, glassine paper, high quality paper, synthetic paper, top coated paper, and the like.
  • Examples of the fabric include woven fabrics and nonwoven fabrics made of various fibrous substances alone or in combination.
  • Examples of the above-mentioned fibrous materials include cotton, staple fiber, Manila hemp, pulp, rayon, acetate fiber, polyester fiber, polyvinyl alcohol fiber, polyamide fiber, and polyolefin fiber.
  • Examples of rubber sheets include natural rubber sheets, butyl rubber sheets, and the like.
  • Examples of foam sheets include foamed polyolefin sheets, foamed polyurethane sheets, foamed polychloroprene rubber sheets, and the like.
  • Examples of metal foil include aluminum foil, copper foil, and the like. Note that the base material that supports the adhesive layer is also referred to as a base material layer in the adhesive sheet.
  • the base material may be formed from a biomass-derived material or a non-biomass-derived material. From the viewpoint of producing a pressure-sensitive adhesive sheet in consideration of reducing dependence on fossil resource-based materials, biomass-derived base materials (typically resin films) are preferably used.
  • the base material may be formed using a recyclable material or a recycled material (also referred to as recycled material).
  • a resin film is preferably used. Resin films (for example, polyester films such as PET films) can be recycled, so whether or not they are made from plant-based materials, reusing the used resin film allows for sustainable reproduction. It is possible to reduce the environmental burden.
  • a recyclable resin film or a recycled resin film is also referred to as a recycled film.
  • the recycled material (for example, recycled film) may be formed from a biomass-derived material or a non-biomass-derived material.
  • the base material constituting the base material-attached pressure-sensitive adhesive sheet one containing a resin film as a base film can be preferably used.
  • the base film is typically an independently shape-maintainable (independent) member.
  • the base material in the technology disclosed herein may be substantially composed of such a base film.
  • the base material may include an auxiliary layer in addition to the base film. Examples of the auxiliary layer include a colored layer, a reflective layer, an undercoat layer, an antistatic layer, etc. provided on the surface of the base film.
  • the resin film is a film whose main component is a resin material (for example, a component contained in the resin film in an amount exceeding 50% by weight).
  • resin films include polyolefin resin films such as polyethylene (PE), polypropylene (PP), and ethylene-propylene copolymers; polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), etc.
  • PET polyethylene terephthalate
  • PBT polybutylene terephthalate
  • PEN polyethylene naphthalate
  • polyester resin film vinyl chloride resin film; vinyl acetate resin film; polyimide resin film; polyamide resin film; fluororesin film; cellophane; and the like.
  • the resin film may be a rubber film such as a natural rubber film or a butyl rubber film. Among these, polyester films are preferred from the viewpoint of handling and processability, and among these, PET films are particularly preferred.
  • resin film is typically a non-porous sheet, and is a concept that is distinguished from so-called non-woven fabrics and woven fabrics (in other words, a concept excluding non-woven fabrics and woven fabrics).
  • the resin film may be an unstretched film, a uniaxially stretched film, or a biaxially stretched film.
  • such resin films may be non-foamed.
  • non-foamed resin film refers to a resin film that has not been intentionally processed to form a foam.
  • the non-foamed resin film may be a resin film with an expansion ratio of less than 1.1 times (for example, less than 1.05 times, typically less than 1.01 times).
  • the above base material may contain fillers (inorganic fillers, organic fillers, etc.), colorants, dispersants (surfactants, etc.), anti-aging agents, antioxidants, ultraviolet rays, etc., as necessary.
  • Various additives such as an absorbent, an antistatic agent, a lubricant, and a plasticizer may be blended.
  • the blending ratio of various additives is about less than 30% by weight (for example, less than 20% by weight, typically less than 10% by weight).
  • the base material may have a single layer structure, or may have a multilayer structure of two layers, three layers, or more. From the viewpoint of shape stability, the base material preferably has a single-layer structure. In the case of a multilayer structure, at least one layer (preferably all layers) is preferably a layer having a continuous structure of the above resin (for example, polyester resin).
  • the method for manufacturing the base material is not particularly limited, and any conventionally known method may be appropriately adopted. For example, conventionally known general film forming methods such as extrusion molding, inflation molding, T-die casting molding, and calender roll molding can be appropriately employed.
  • the surface of the base material may be subjected to conventionally known surface treatments such as corona discharge treatment, plasma treatment, ultraviolet irradiation treatment, acid treatment, alkali treatment, and application of an undercoat.
  • Such surface treatment may be a treatment for improving the adhesion between the base material and the adhesive layer, in other words, the ability of the adhesive layer to anchor to the base material.
  • the back surface of the base material may be subjected to a peeling treatment as necessary.
  • the peeling treatment is performed by applying a general silicone-based, long-chain alkyl-based, or fluorine-based peeling agent to a thin film, typically about 0.01 ⁇ m to 1 ⁇ m (for example, 0.01 ⁇ m to 0.1 ⁇ m). It can be a process to add. By performing such a peeling treatment, effects such as facilitating the unwinding of a roll-shaped adhesive sheet can be obtained.
  • the thickness of the base material is not particularly limited. From the viewpoint of preventing the pressure-sensitive adhesive sheet from becoming too thick, the thickness of the base material can be, for example, approximately 200 ⁇ m or less, preferably approximately 150 ⁇ m or less, and more preferably approximately 100 ⁇ m or less.
  • the thickness of the base material may be approximately 70 ⁇ m or less, approximately 50 ⁇ m or less, or approximately 30 ⁇ m or less (for example, approximately 25 ⁇ m or less) depending on the purpose and manner of use of the adhesive sheet. In some embodiments, the thickness of the base film layer may be about 20 ⁇ m or less, about 15 ⁇ m or less, about 10 ⁇ m or less (eg, about 5 ⁇ m or less).
  • the thickness of the adhesive layer can be increased even if the total thickness of the adhesive sheet is the same.
  • Increasing the thickness of the adhesive layer can be advantageous from the viewpoint of improving adhesion to adherends and base materials.
  • the lower limit of the base material is not particularly limited. From the viewpoint of handleability and processability of the adhesive sheet, it is appropriate that the thickness of the base material is approximately 0.5 ⁇ m or more (for example, 1 ⁇ m or more), preferably approximately 2 ⁇ m or more, for example, approximately 1 ⁇ m or more.
  • the thickness may be 6 ⁇ m or more, approximately 8 ⁇ m or more, or approximately 10 ⁇ m or more.
  • the thickness of the substrate may be about 15 ⁇ m or more, and about 25 ⁇ m or more.
  • a release liner can be used during formation of the adhesive layer, production of the adhesive sheet, storage of the adhesive sheet before use, distribution, shape processing, etc.
  • the release liner is not particularly limited, and for example, a release liner having a release treatment layer on the surface of a liner base material such as a resin film or paper, a release liner made of a fluorine-based polymer (polytetrafluoroethylene, etc.), etc. may be used. be able to.
  • the release treatment layer may be formed by surface-treating the liner base material with a release agent such as a silicone-based, long-chain alkyl-based, fluorine-based, or molybdenum sulfide release agent.
  • a release agent such as a silicone-based, long-chain alkyl-based, fluorine-based, or molybdenum sulfide release agent.
  • the liner base material like the base material of the above-mentioned adhesive sheet, one formed using a biomass-derived material or a recycled material (recycled film, etc.) can be preferably used.
  • the total thickness of the adhesive sheet disclosed herein (which includes an adhesive layer and may further include a base layer, but does not include a release liner) is not particularly limited.
  • the total thickness of the adhesive sheet is, for example, approximately 1 mm or less, may be approximately 500 ⁇ m or less, and may be approximately 300 ⁇ m or less, and from the viewpoint of thinning, approximately 200 ⁇ m or less is appropriate, and approximately 150 ⁇ m or less. (For example, approximately 100 ⁇ m or less).
  • the thickness of the pressure-sensitive adhesive sheet can be approximately 70 ⁇ m or less, and may be approximately 55 ⁇ m or less, for example.
  • the lower limit of the thickness of the adhesive sheet is, for example, 0.1 ⁇ m or more (for example, 0.5 ⁇ m or more), suitably about 3 ⁇ m or more, preferably about 10 ⁇ m or more, more preferably about 15 ⁇ m or more, It may be about 20 ⁇ m or more, or about 40 ⁇ m or more.
  • a pressure-sensitive adhesive sheet having a thickness of a predetermined value or more tends to have good adhesion to an adherend and also tends to have excellent handling properties.
  • the thickness of the adhesive layer becomes the total thickness of the adhesive sheet.
  • the pressure-sensitive adhesive sheet preferably has a 180 degree peel strength against a stainless steel plate (adhesive strength against SUS) of 8.0 N/10 mm or more.
  • a pressure-sensitive adhesive sheet exhibiting such adhesion to SUS can exhibit good fixing performance, for example, in the use of fixing members.
  • the adhesive strength to SUS is more preferably approximately 8.2 N/10 mm or more, further preferably 8.5 N/10 mm or more, may be 8.8 N/10 mm or more, may be 9.0 N/10 mm or more, and 9.
  • the adhesive force to SUS is not particularly limited, but in consideration of other requirements (for example, thinning of the adhesive layer, etc.), it may be, for example, 20N/10mm or less, 18N/10mm or less, 16N /10mm or less.
  • the adhesive strength to SUS is measured using an SUS plate as an adherend under the conditions of a tensile speed of 300 mm/min and a peel angle of 180 degrees in a measurement environment of 23° C. and 50% RH.
  • the above adhesion to SUS is a property that is measured without supplying oil or aqueous solvent after attachment to an adherend.
  • the above-mentioned SUS adhesive force may be referred to as "initial adhesive force F 0 " hereinafter. More specifically, the initial adhesive force F 0 is measured by the method described in Examples below.
  • Adhesive force maintenance rate RA (Adhesive force after immersion F A /Initial adhesive force F 0 ) x 100; It is preferable that the adhesive force maintenance rate RA expressed by RA is 60% or more.
  • the adhesive force after immersion F A in the above formula is 180 degrees, which is measured after attaching the adhesive sheet to be evaluated to a stainless steel plate and immersing it in oleic acid for two weeks in an environment of 40°C and 90% RH. This is the peel strength, and the initial adhesive force F 0 in the above formula is the above-mentioned adhesive force to SUS.
  • the post-immersion adhesive force F A is measured by the method described in Examples below.
  • the adhesive force maintenance rate R A is calculated from the above-mentioned post-immersion adhesive force F A and the above-mentioned initial adhesive force F 0 by the above formula.
  • the adhesive strength retention rate R A is more preferably 63% or more (for example, 65% or more), and 67%. More preferably, it is at least 70% (for example, at least 70%), and may be at least 73%, at least 75%, at least 80%, or at least 85%.
  • the upper limit of the adhesive strength maintenance rate RA is not particularly limited.
  • the adhesive strength maintenance rate R A is typically 100% or less, and from the viewpoint of compatibility with other properties (for example, initial adhesive strength F 0 and aqueous solvent resistance), in some embodiments, for example, It may be 98% or less, 95% or less, 90% or less, 85% or less, or 80% or less.
  • the post-immersion adhesive force F A is preferably 4.8 N/10 mm or more (for example, 5.0 N/10 mm or more), It is more preferably 5.3N/10mm or more (for example, 5.5N/10mm or more), even more preferably 6.0N/10mm or more, it may be 6.5N/10mm or more, and 7.0N /10mm or more, or 7.5N/10mm or more.
  • the upper limit of the post-immersion adhesive force FA is not particularly limited.
  • the adhesive strength F after immersion may be, for example, 19 N/10 mm or less, and 17 N /10mm or less, or 15N/10mm or less.
  • Adhesive force maintenance rate RB (Adhesive force after immersion F B /Initial adhesive force F 0 ) x 100; It is preferable that the adhesive force maintenance rate RB expressed by RB is 70% or more.
  • the adhesive force after immersion F B in the above formula is calculated by pasting the adhesive sheet to be evaluated on a stainless steel plate and applying a 50% isopropyl alcohol aqueous solution (mixed in a volume ratio of 1:1) in an environment of 40°C and 90% RH.
  • the initial adhesive force F 0 in the above formula is the above-mentioned adhesive force to SUS. More specifically, the post-immersion adhesive strength FB is measured by the method described in Examples below.
  • the adhesive force maintenance rate R B is calculated from the above-mentioned post-immersion adhesive force F B and the above-mentioned initial adhesive force F 0 by the above formula.
  • the above-mentioned adhesive strength retention rate is R B is preferably 75% or more, more preferably 80% or more, even more preferably 84% or more (for example, 85% or more), may be 87% or more, and may be 90% or more.
  • the upper limit of the adhesive force maintenance rate RB is not particularly limited.
  • the adhesive force retention rate R B is typically 100% or less, and in some embodiments, for example, from the viewpoint of compatibility with other properties (for example, initial adhesive force F 0 and oil resistance), it is 99% or less.
  • the post-immersion adhesive force F B is preferably 6.0 N/10 mm or more (for example, 6.5 N/10 mm or more). , is more preferably 7.0 N/10 mm or more (for example, 7.5 N/10 mm or more), even more preferably 8.0 N/10 mm or more, may be 8.2 N/10 mm or more, and 8. It may be 5N/10mm or more, or it may be 8.7N/10mm or more.
  • the upper limit of the post-immersion adhesive force FB is not particularly limited.
  • the adhesive strength after immersion F B may be, for example, 19 N/10 mm or less, and 18 N /10mm or less, 17N/10mm or less, or 15N/10mm or less.
  • the adhesive sheet may include a biomass-derived material, and the biomass carbon ratio may be greater than or equal to a predetermined value.
  • the biomass carbon ratio of the adhesive sheet is, for example, 1% or more, and may be 10% or more, preferably 30% or more, and more preferably 50% or more.
  • a high biomass carbon ratio in the adhesive sheet means that less fossil resource-based materials, such as petroleum, are used. From this point of view, the higher the biomass carbon ratio of the pressure-sensitive adhesive sheet, the more preferable it is.
  • the biomass carbon ratio of the adhesive sheet may be 55% or more, 60% or more, 70% or more, 75% or more, 80% or more, or more than 80%. .
  • the upper limit of the biomass carbon ratio is 100% by definition, and may be 99% or less, and from the viewpoint of material availability, it may be 95% or less, or 90% or less. In some embodiments, from the viewpoint of facilitating good adhesive performance, the biomass carbon ratio of the adhesive sheet may be, for example, 90% or less, 85% or less, or 80% or less.
  • the use of the pressure-sensitive adhesive sheet disclosed herein is not particularly limited, and can be used for various purposes.
  • the adhesive sheet disclosed herein is suitable for use in fixing various members that can come into contact with one or both of oil and aqueous solvents by taking advantage of its characteristics of being able to achieve both high levels of adhesive strength, oil resistance, and aqueous solvent resistance. can be used.
  • a typical example of such uses is for fixing members in various types of portable equipment. For example, it is suitable for use in fixing members in portable electronic devices.
  • Non-limiting examples of the above-mentioned portable electronic devices include mobile phones, smartphones, tablet computers, notebook computers, and various wearable devices (e.g., wrist-wear type that is worn on the wrist like a wristwatch, and Modular type that is attached to a part of the body, eyewear type that includes glasses type (monocular type and binocular type, including head-mounted type), clothing type that is attached to shirts, socks, hats, etc. in the form of accessories, and earphones. digital cameras, digital video cameras, audio equipment (portable music players, IC recorders, etc.), calculators (calculators, etc.), portable game devices, electronic dictionaries, electronic notebooks, electronic books, and in-vehicle devices.
  • wearable devices e.g., wrist-wear type that is worn on the wrist like a wristwatch, and Modular type that is attached to a part of the body
  • eyewear type that includes glasses type (monocular type and binocular type, including head-mounted type)
  • clothing type that is attached
  • portable devices include mechanical watches, pocket watches, flashlights, hand mirrors, commuter pass cases, and the like. Note that in this specification, "portable” does not mean that it is sufficient to simply be able to carry it; it also means that it has a level of portability that allows an individual (standard adult) to carry it relatively easily. shall mean.
  • FIG. 4 is an example schematically showing a portable electronic device (smartphone) in which the adhesive sheet disclosed herein is used.
  • a battery (heat generating element) 540 is built inside the casing 520 of the portable electronic device 500.
  • the portable electronic device 500 is configured to include an adhesive sheet 550.
  • the adhesive sheet 550 has the form of a double-sided adhesive sheet (double-sided adhesive sheet) that fixes members constituting the portable electronic device 500.
  • the portable electronic device 500 includes a touch panel 570 whose display section also functions as an input section.
  • the adhesive sheet disclosed herein is preferably used as a component (member joining means) of the above-mentioned portable electronic devices.
  • the adhesive sheet disclosed herein may have an adhesive layer containing an acrylic polymer with a high biomass carbon ratio in some embodiments, conventional general acrylic adhesives (i.e. By being used as a substitute for acrylic adhesives in various applications where acrylic adhesives (acrylic adhesives with a low biomass carbon ratio) are used, it can contribute to reducing dependence on fossil resource-based materials.
  • the adhesive sheet disclosed herein can be preferably used as an adhesive sheet with reduced dependence on fossil resource materials.
  • the matters disclosed by this specification include the following.
  • the acrylic polymer is a polymer of monomer components containing n-heptyl acrylate, The content of the tackifying resin is more than 10 parts by weight based on 100 parts by weight of the acrylic polymer,
  • the pressure-sensitive adhesive layer is a pressure-sensitive adhesive sheet whose swelling degree with respect to ethyl acetate is 100 or less.
  • the phenolic tackifying resin includes a terpene phenol resin, The adhesive sheet according to [4] above, wherein the content of the terpene phenol resin is 20 parts by weight or more based on 100 parts by weight of the acrylic polymer.
  • a mobile device An adhesive sheet is bonded to the member constituting the electronic device,
  • the adhesive sheet has an adhesive layer containing an acrylic polymer and a tackifying resin,
  • the acrylic polymer is a polymer of monomer components containing n-heptyl acrylate,
  • the content of the tackifying resin is more than 10 parts by weight based on 100 parts by weight of the acrylic polymer,
  • the adhesive layer has a swelling degree of 100 or less with respect to ethyl acetate.
  • the phenolic tackifying resin includes a terpene phenol resin, The portable device according to [15] above, wherein the content of the terpene phenol resin is 20 parts by weight or more based on 100 parts by weight of the acrylic polymer.
  • the adhesive sheet is configured as a double-sided adhesive sheet having a resin film as a supporting base material, and the adhesive layer provided on one surface and the other surface of the supporting base material.
  • the mobile device according to any one of [11] to [19] above.
  • one adhesive side of an adhesive sheet (double-sided adhesive sheet) was lined with a PET film with a thickness of 50 ⁇ m, and cut into a size of 10 mm in width and 100 mm in length.
  • the other adhesive surface of the measurement sample is pressed onto the surface of a stainless steel plate (SUS304BA plate) that has been cleaned with ethyl acetate by making one reciprocation with a 2 kg roller. After leaving this in the same environment for 30 minutes, it was immersed in an oleic acid bath and kept in an environment of 40° C. and 90% RH for two weeks.
  • Adhesive force maintenance rate R A [%] (Adhesive force after immersion F A /Initial adhesive force F 0 ) x 100;
  • the adhesive force maintenance rate RA is calculated by:
  • Adhesive force maintenance rate R B [%] (Adhesive force after immersion F B /Initial adhesive force F 0 ) x 100;
  • the adhesive force maintenance rate RB is calculated by:
  • the package is soaked in 50 mL of ethyl acetate and kept at room temperature (approximately 23° C.) for 7 days. Thereafter, the package is taken out, ethyl acetate adhering to the outer surface is wiped off, and the weight (W S4 ) of the package is measured. The package is then dried at 130° C. for 2 hours and the weight (Wg 5 ) of the package is measured.
  • n-HpA is a compound having a biomass-derived heptyl group at the ester end, which was synthesized using biomass-derived heptyl alcohol.
  • isocyanate-based crosslinking agent "Coronate L” (a 75% ethyl acetate solution of trimethylolpropane/tolylene diisocyanate trimer adduct) manufactured by Tosoh Corporation was used; as the epoxy-based crosslinking agent, The product name "TETRAD-C” (1,3-bis(N,N-diglycidylaminomethyl)cyclohexane) manufactured by Mitsubishi Gas Chemical Co., Ltd. was used.
  • Example 2 In the preparation of the adhesive composition of Example 1, tackifying resin A (trade name "YS Polystar T115", manufactured by Yasuhara Chemical Co., Ltd., terpene phenol resin, softening point 115°C, hydroxyl value 60 mgKOH/g) was used instead of tackifying resin B. )It was used. A double-sided pressure-sensitive adhesive sheet with a base material according to this example was produced in the same manner as in Example 1 except that the obtained pressure-sensitive adhesive composition was used.
  • tackifying resin A trade name "YS Polystar T115", manufactured by Yasuhara Chemical Co., Ltd., terpene phenol resin, softening point 115°C, hydroxyl value 60 mgKOH/g
  • Examples 10 to 12 A solution of acrylic polymer (A3) was obtained in the same manner as in the synthesis of acrylic polymer (A1), except that the monomer composition was changed to 90 parts of n-HpA and 10 parts of AA, and the concentration of monomer components during polymerization was adjusted. Ta. Adhesive compositions according to each example were prepared in the same manner as in Example 1 except that the above acrylic polymer (A3) was used and the composition was changed to that shown in Table 1. A double-sided adhesive sheet with a base material according to the example was produced.
  • a pressure-sensitive adhesive composition according to this example was prepared in the same manner as in Example 5, except that the amount of tackifier resin A used was 0 parts (Comparative Example 1) or 5 parts (Comparative Example 2).
  • a double-sided pressure-sensitive adhesive sheet with a base material according to this example was produced using the composition.
  • a solution of acrylic polymer (A4) was obtained basically in the same manner as the synthesis of acrylic polymer (A1) except that the monomer composition was changed to 90 parts of 2-ethylhexyl acrylate (2EHA) and 10 parts of AA.
  • Adhesive compositions according to each example were prepared in the same manner as in Example 1 except that the above acrylic polymer (A4) was used and the composition was changed to that shown in Table 2.
  • a double-sided adhesive sheet with a base material according to the example was produced.
  • a solution of acrylic polymer (A5) was obtained basically in the same manner as the synthesis of acrylic polymer (A1) except that the monomer composition was changed to 95 parts of n-butyl acrylate (BA) and 5 parts of AA.
  • a pressure-sensitive adhesive composition according to this example was prepared in the same manner as in Example 1 except that the above acrylic polymer (A5) was used and the composition was changed to that shown in Table 2.
  • a double-sided pressure-sensitive adhesive sheet with a base material was produced.
  • Tables 1 and 2 show the outline and evaluation results of the pressure-sensitive adhesive sheets of each example.
  • the adhesive layers according to Examples 1 to 12 contained an acrylic polymer containing n-heptyl acrylate as a monomer component and an adhesive in an amount exceeding 10 parts per 100 parts of the acrylic polymer.
  • the swelling degree with respect to ethyl acetate was 100 or less.
  • the adhesive sheets according to these Examples had good initial adhesive strength F 0 , adhesive strength retention rate RA against oil, and adhesive strength retention rate RB against aqueous solvent. In other words, it achieved a high level of adhesion, oil resistance, and aqueous solvent resistance.
  • the surface free energy ⁇ of the adhesive layers according to Examples 1 to 12 were all within the range of 10 to 35 mJ/m 2 .
  • Comparative Examples 3 and 4 are examples in which an acrylic polymer which does not contain n-heptyl acrylate and is a polymer of a monomer component mainly composed of 2EHA is used, and Comparative Example 3 has a low initial adhesive force F 0 .
  • Comparative Example 4 in which the content of the tackifier resin was increased, although the initial adhesive force F 0 increased, the degree of swelling greatly exceeded 100, and the adhesive force retention rate RA against oil content clearly decreased.
  • Comparative Example 5 is an example in which an acrylic polymer which does not contain n-heptyl acrylate and is a polymer of monomer components mainly composed of BA has insufficient resistance to aqueous solvents.
  • Adhesive sheet Supporting base material 10A First side 10B Second side (back side) 21 Adhesive layer (first adhesive layer) 21A Adhesive surface (first adhesive surface) 21B Second adhesive surface 22 Adhesive layer (second adhesive layer) 22A Adhesive surface (second adhesive surface) 31, 32 Release liner 100, 200, 300 Adhesive sheet with release liner

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Adhesive Tapes (AREA)
  • Adhesives Or Adhesive Processes (AREA)
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JP2020164844A (ja) * 2019-03-28 2020-10-08 積水化学工業株式会社 感圧粘着剤組成物及び粘着テープ

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