Filamentous pressure-sensitive adhesive body

Abstract

The present invention provides an adhesive material having high adhesive force and easy disassembly. The present invention also provides a laminate of a filamentous pressure-sensitive adhesive body and an electronic device member. The present invention pertains to a filamentous pressure-sensitive adhesive body comprising a core material and a pressure-sensitive adhesive agent that covers the surface of the core material in the longitudinal direction. The pressure-sensitive adhesive agent contains a base polymer and air bubbles.

Description

Thread-like adhesive body

[0001] The present invention relates to a thread-like adhesive material.

[0002] Narrow adhesive materials, such as pressure-sensitive adhesive tapes, are sometimes used for bonding electronic devices, housings, and the like. For example, Patent Document 1 discloses a double-sided pressure-sensitive adhesive tape that includes a pressure-sensitive adhesive layer laminate formed by laminating two or more pressure-sensitive adhesive layers, the pressure-sensitive adhesive layers containing a low-polarity filler. Furthermore, Patent Document 2 discloses a pressure-sensitive adhesive tape that includes an acrylic pressure-sensitive adhesive and a viscoelastic layer containing hollow particles or bubbles.

[0003] Japanese Patent No. 6975189 Japanese Patent No. 7024928

[0004] In applications for fastening housings / components of medium- to large-sized home appliances, such as television and display housings, high adhesive reliability as well as ease of disassembly are particularly required. The pressure-sensitive adhesive tapes described in Patent Documents 1 and 2 above have the problem that there is still room for improvement in adhesive strength and that they do not have ease of disassembly.

[0005] The present invention has been made in view of the above-mentioned conventional circumstances, and has as its object to provide an adhesive material that has high adhesive strength and is easily dismantlable.

[0006] As a result of intensive research into solving the above-mentioned problems, the inventors discovered that the above-mentioned problems can be solved by incorporating a base polymer and air bubbles into a thread-like adhesive body comprising a core material and an adhesive coating the surface of the core material, thereby solving the present invention.

[0007] That is, the present invention relates to the following: [1] A thread-like adhesive body comprising a core material and a pressure-sensitive adhesive coating the longitudinal surface of the core material, the pressure-sensitive adhesive containing a base polymer and bubbles. [2] The thread-like adhesive body according to [1], wherein the pressure-sensitive adhesive further contains particles, the tensile modulus of the particles being at least 30 times that of the base polymer. [3] The thread-like adhesive body according to [2], wherein the tensile modulus of the particles is 0.01 to 3 GPa. [4] The thread-like adhesive body according to [2], wherein the particles are contained in an amount of 10 to 60 parts by mass per 100 parts by mass of the base polymer. [5] The thread-like adhesive body according to [1], wherein the pressure-sensitive adhesive contains more than 0% by volume and not more than 5% by volume of bubbles having a diameter of 20 μm or less. [6] The thread-like adhesive body according to [1], wherein the adhesive has an increased adhesive strength when heated at 40°C or higher and 80°C or lower for 1 hour. [7] The thread-like adhesive material according to [1], wherein the core material is a multifilament yarn. [8] A laminate of the thread-like adhesive material according to any one of [1] to [7] and an electronic device member.

[0008] According to the present invention, an adhesive material having high adhesive strength and easy dismantling properties can be provided, and a laminate of the above-mentioned thread-like adhesive material and an electronic device member can be provided.

[0009] 1A to 1C are diagrams illustrating a method for preparing a sample for a cleavage peeling test.

[0010] Hereinafter, embodiments of the thread-like adhesive material of the present invention will be described in detail. Note that the present invention is not limited to the embodiments described below. Furthermore, when the expression "to" is used in this specification, it is used as an expression including the numerical values ​​or physical property values ​​before and after it.

[0011] [Thread-like adhesive body] The thread-like adhesive body according to an embodiment of the present invention comprises a core material and a pressure-sensitive adhesive that coats the surface of the core material in the longitudinal direction, and the pressure-sensitive adhesive contains a base polymer and air bubbles.

[0012] Here, thread-like refers to a shape in which the longitudinal length is sufficiently longer than the width length, and the ratio of the length of the long axis to the length of the short axis in the cross-sectional shape (long axis / short axis) is, for example, 200 or less, preferably 100 or less, more preferably 50 or less, even more preferably 10 or less, still more preferably 5 or less, and particularly preferably 3 or less, and also refers to a shape in which it can be bent in various directions and at various angles like a thread.

[0013] The thread-like adhesive body according to an embodiment of the present invention can be bent in various directions and angles, and can therefore be bent to match the shape of the attachment area, thereby accommodating a variety of shapes of attachment areas.

[0014] The core material and adhesive constituting the thread-like adhesive body according to an embodiment of the present invention will be described below.

[0015] <Core Material> The thread-like adhesive body according to the embodiment of the present invention has a core material. By having a core material, the thread-like adhesive body can be easily pulled out and dismantled (easily dismantled). The core material is preferably thread-shaped.

[0016] In this specification, the pull-out dismantling property of a thread-like adhesive body means the ability to dismantle an assembly in which adherends are joined together using a thread-like adhesive body by pulling out the thread-like adhesive body from the assembly.

[0017] The core material preferably has multiple filaments and is a multifilament yarn obtained by doubling or twisting the multiple filaments. When the core material is a multifilament yarn, sufficient strength and stable physical properties can be obtained. As a result, a thread-like adhesive body with low quality variation, excellent strength, and excellent adhesive force can be obtained. In addition, multifilament yarn is preferred because it makes it easier for voids to form between the filaments, thereby alleviating stress concentration in the adhesive coating the surface of the core material and dispersing the stress.

[0018] The number of filaments contained in the core material is preferably 4 or more, more preferably 10 or more, and particularly preferably 20 or more, from the viewpoint of adhesive strength.

[0019] On the other hand, if the thickness (fineness) of the core material is kept at the same level, as the number of filaments increases, each filament becomes thinner (fineness decreases). If each filament becomes too thin, the strength of the core material and handling properties may decrease, so the number of filaments is preferably 2,000 or less, more preferably 1,500 or less, and particularly preferably 1,000 or less.

[0020] There are no particular limitations on the type of resin used for the filament, and it may be selected appropriately depending on the required properties such as strength, mass, hardness, etc. Examples include materials containing polymeric materials such as thermoplastic polymers, thermosetting polymers, and rubber.

[0021] Specifically, polymeric materials such as rayon, cupra, acetate, promix, nylon, aramid, vinylon, vinylidene, polyvinyl chloride, acrylic, polyolefin (polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, etc.), polyester resin (polyethylene terephthalate, etc.), vinyl chloride resin, vinyl acetate resin, polyimide resin, polyamide resin, fluororesin, polyurethane, polychlor, polylactic acid, etc.; rubbers such as synthetic rubber (natural rubber, polyurethane, etc.); foams such as polyurethane foam and polychloroprene rubber foam, etc. can be used. Among these, polyester resin is preferred, and polyethylene terephthalate is more preferred.

[0022] The content of the filaments in the core material is preferably from 10 to 100% by mass, more preferably from 50 to 100% by mass, and particularly preferably from 80 to 100% by mass.

[0023] The core material may contain various additives, such as fillers (inorganic fillers, organic fillers, etc.), antioxidants, antioxidants, ultraviolet absorbers, antistatic agents, lubricants, plasticizers, colorants (pigments, dyes, etc.), etc. The surface of the core material may be subjected to known or conventional surface treatments, such as corona discharge treatment, plasma treatment, or application of a primer.

[0024] The shape of the core material is not particularly limited and may be adjusted appropriately depending on the required properties such as strength, mass, hardness, etc. The cross-sectional shape of the core material is typically circular, but may also be various other shapes such as oval, polygonal, etc.

[0025] The core material may have a plurality of filaments, and may be a yarn obtained by combining a filament with a spun yarn, textured yarn, hollow yarn, etc. by twisting it together. Examples of textured yarn include textured yarns that have been subjected to crimping, bulking, or the like, and are generally called textured yarns, bulky yarns, and stretch yarns.

[0026] The thickness of the core material is not particularly limited, and may be adjusted appropriately depending on the application so that the thickness of the thread-like adhesive body is appropriate.

[0027] The twist number of the core material is preferably 1 turn / m or more. If the twist number is 1 turn / m or more, the impact resistance of the thread-like adhesive body is improved. The twist number of the core material is more preferably 20 turns / m or more, and even more preferably 50 turns / m or more.

[0028] On the other hand, in order to ensure that the core material is sufficiently deformed when multiple articles are bonded together and to increase the amount of adhesive attached per unit length, it is preferable that the twist of the core material is not too strong. Therefore, the number of twists of the core material is preferably 500 times / m or less, more preferably 300 times / m or less, and even more preferably 200 times / m or less.

[0029] Furthermore, when the core material is twisted, it is preferable to also control the twist coefficient K, which is expressed by the following formula (A), from the same viewpoint as above. The twist coefficient K is an index for discussing the influence of twist (influence on the core material's cohesion, ease of deformation, amount of adhesive attached, etc.) regardless of the thickness of the core material. In other words, the influence of the number of twists on the core material differs depending on the thickness of the core material, but if the twist coefficient K is the same, it indicates that the influence of twist on the core material is the same regardless of the thickness of the core material.

[0030] The twist coefficient K is preferably 0 or more, and more preferably greater than 0. On the other hand, if the twist coefficient K is 200 or less, the flexibility of the core material, and therefore the thread-like adhesive body, is improved, making it easier to apply to complex shapes such as curved portions, bent portions, uneven portions, and narrow areas. Therefore, the twist coefficient K is preferably 200 or less, more preferably 100 or less, and even more preferably less than 50.

[0031]

[0032] In formula (A), K represents the twist coefficient, T represents the number of twists (turns / m), and D represents the fineness (dtex).

[0033] The content of the core material in the thread-like adhesive is preferably 10% by mass or more, more preferably 20% by mass or more, and particularly preferably 30% by mass or more, from the viewpoint of suppressing a decrease in the strength of the thread-like adhesive, and is preferably 90% by mass or less, more preferably 80% by mass or less, and particularly preferably 70% by mass or less, from the viewpoint of suppressing the core material from coming out to the surface.

[0034] <Adhesive> The thread-like adhesive body according to an embodiment of the present invention has an adhesive that coats a core material, and the adhesive contains a base polymer and air bubbles. The adhesive according to this embodiment can be formed from an adhesive composition, and the adhesive may be an adhesive composition. Furthermore, the adhesive may form a layer (adhesive layer).

[0035] The adhesive preferably covers the entire longitudinal surface of the core material. The entire longitudinal surface of the core material refers to the entire circumferential surface of the core material, and means the entire 360° circumference of the surface of the core material, centered on the center line of the longitudinal direction of the core material.

[0036] However, the end faces of the core material may or may not be coated with adhesive. For example, if the thread-like adhesive body is cut during production or use, the end faces of the core material may not be coated with adhesive.

[0037] By coating the entire longitudinal surface of the core material with adhesive, a thread-like adhesive body with excellent strength can be obtained. This is presumably because the core material is not exposed on the surface, preventing stress from concentrating on one part of the core material and causing breakage.

[0038] The coverage of the core material with the adhesive (the area (%) of the adhesive per unit area of ​​the surface of the core material) is preferably 50 area% or more, more preferably 80 area% or more, even more preferably 90 area% or more, and particularly preferably 95 area% or more. If the coverage of the core material is 50 area% or more, breakage of the core material can be prevented and a thread-like adhesive body with excellent strength can be obtained.

[0039] The adhesive forming the adhesive layer may be impregnated into the core material. Here, "the adhesive is impregnated into the core material" means that the adhesive is present between multiple filaments in the core material. When the adhesive is impregnated into the core material, the adhesive and the core material maintain adhesion, making them less likely to peel off, and improving the strength of the thread-like adhesive body.

[0040] (Base Polymer) The pressure-sensitive adhesive in this embodiment is formed from a pressure-sensitive adhesive containing a base polymer as a main component. The type of pressure-sensitive adhesive is not particularly limited, and examples thereof include acrylic pressure-sensitive adhesives, rubber pressure-sensitive adhesives, vinyl alkyl ether pressure-sensitive adhesives, silicone pressure-sensitive adhesives, polyester pressure-sensitive adhesives, polyamide pressure-sensitive adhesives, urethane pressure-sensitive adhesives, fluorine-based pressure-sensitive adhesives, and epoxy pressure-sensitive adhesives.

[0041] Among these, from the viewpoint of adhesiveness, acrylic adhesives and rubber adhesives are preferred, and acrylic adhesives are more preferred. Note that the adhesives may be used alone or in combination of two or more.

[0042] The rubber-based adhesive is based on a rubber-based polymer such as natural rubber, styrene-isoprene-styrene block copolymer, styrene-butadiene-styrene block copolymer, styrene-ethylene-butylene-styrene block copolymer, styrene-butadiene rubber, polybutadiene, polyisoprene, polyisobutylene, butyl rubber, chloroprene rubber, or silicone rubber.

[0043] Here, "acrylic pressure-sensitive adhesive" refers to a pressure-sensitive adhesive having an acrylic polymer as the base polymer (the main component of the polymer, i.e., a component accounting for 50% by mass or more). "Acrylic polymer" refers to a polymer having a monomer having at least one (meth)acryloyl group in one molecule (hereinafter, this may be referred to as "acrylic monomer") as the main constituent monomer component (the main component of the monomer, i.e., a component accounting for more than 50% by mass of the total amount of monomers constituting the acrylic polymer). Furthermore, in this specification, "(meth)acryloyl" refers to acryloyl and methacryloyl in a comprehensive sense. Similarly, "(meth)acrylic acid ester" refers to acrylic acid ester and methacrylic acid ester, and "(meth)acrylic" refers to acrylic and methacrylic in a comprehensive sense.

[0044] The acrylic polymer is preferably a polymer of a monomer raw material that contains, for example, an alkyl(meth)acrylate as a main monomer and may further contain a secondary monomer copolymerizable with the main monomer, where the main monomer refers to a component that accounts for more than 50% by mass of the monomer composition in the monomer raw material.

[0045] As the alkyl(meth)acrylate, for example, a compound represented by the following formula (1) can be suitably used: CH ２ = C(R １ ) COOR ２ (1) Here, R in the above formula (1) １ is a hydrogen atom or a methyl group. ２ is a chain alkyl group having 1 to 20 carbon atoms. Hereinafter, this range of carbon atoms will be referred to as "C １－２０ " is sometimes expressed as ".

[0046] R ２ is C １－２０Examples of alkyl(meth)acrylates, which are chain alkyl groups, 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(meth)acrylate, 2-ethylhexyl(meth)acrylate, octyl(meth)acrylate, and isooctyl(meth)acrylate. Examples of alkyl (meth)acrylates include methyl (meth)acrylate, ...

[0047] From the viewpoint of adhesive stability, etc., R ２ is C １－１４ (For example, C ２－１０ , typically C ４－８ It is suitable to use alkyl (meth)acrylate, which is a chain alkyl group of the formula (I), as the main monomer.

[0048] From the viewpoint of adhesive properties, R １ is a hydrogen atom and R ２ is C ４－８ alkyl acrylate (hereinafter simply referred to as C ４－８ It is preferable to use alkyl acrylates (also called alkyl acrylates) as the main monomer. Preferred examples include n-butyl acrylate (BA) and 2-ethylhexyl acrylate (2EHA).

[0049] That is, the PSA contains an acrylic polymer, and the amount of n-butyl acrylate or 2-ethylhexyl acrylate relative to the total amount of the monomer components constituting the acrylic polymer is preferably more than 50% by mass, more preferably 60% by mass or more, and even more preferably 70% by mass or more. From the viewpoint of suppressing a decrease in adhesive strength, it is preferably 97% by mass or less, more preferably 95% by mass or less, and even more preferably 90% by mass or less.

[0050] In this embodiment, C is used relative to the total amount of monomer components constituting the acrylic polymer. ４－８ The composition can be preferably implemented in an embodiment in which the total amount of alkyl acrylate is more than 50% by mass, and may be 60% by mass or more, 70% by mass or more, or 85% by mass or more. ４－８ The proportion of alkyl acrylate is usually suitably 99.5% by mass or less, and may be 98% by mass or less (for example, less than 97% by mass).

[0051] The total amount of alkyl(meth)acrylate relative to the total amount of monomer components constituting the acrylic polymer is typically more than 50% by mass, and can be, for example, 70% by mass or more, or 85% by mass or more, or even 90% by mass or more. The proportion of alkyl(meth)acrylate in the monomer components is typically less than 100% by mass, and from the viewpoint of cohesive strength, etc., it is usually appropriate to set it to 99.5% by mass or less, and it may be 98% by mass or less (for example, less than 97% by mass).

[0052] The acrylic polymer may contain a carboxyl group-containing monomer as a monomer component constituting the acrylic polymer. Examples of the carboxyl group-containing monomer include ethylenically unsaturated monocarboxylic acids such as acrylic acid, methacrylic acid, carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, crotonic acid, and isocrotonic acid; ethylenically unsaturated dicarboxylic acids such as maleic acid, itaconic acid, and citraconic acid, and their anhydrides (maleic anhydride, itaconic anhydride, etc.); and the like. These can be used alone or in combination of two. Among them, acrylic acid (AA) and methacrylic acid (MAA) are preferred as carboxyl group-containing monomers. AA is particularly preferred.

[0053] In an embodiment in which a carboxyl group-containing monomer is copolymerized with an acrylic polymer, the content of the carboxyl group-containing monomer relative to the total amount of the monomer components constituting the acrylic polymer is not particularly limited, and can be, for example, 0.2% by mass or more (typically 0.5% by mass or more), and usually 1% by mass or more is appropriate, and may be 2% by mass or more, or 3% by mass or more. The upper limit of the content of the carboxyl group-containing monomer is not particularly limited, but from the viewpoint of maintaining good adhesive properties, it can be, for example, 15% by mass or less, or may be 12% by mass or less, or may be 10% by mass or less.

[0054] The acrylic polymer may be formed using, as a monomer component, one or more of the following functional group-containing monomers (excluding the above-mentioned carboxy group-containing monomers): Hydroxyl group-containing monomers: hydroxyalkyl (meth)acrylates such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate; unsaturated alcohols such as vinyl alcohol and allyl alcohol; and polypropylene glycol mono(meth)acrylate. Amide group-containing monomers: (meth)acrylamide, N,N-dimethyl (meth)acrylamide, N-butyl (meth)acrylamide, N-methylol (meth)acrylamide, N-methylolpropane (meth)acrylamide, N-methoxymethyl (meth)acrylamide, and N-butoxymethyl (meth)acrylamide. Amino group-containing monomers: for example, aminoethyl (meth)acrylate, N,N-dimethylaminoethyl (meth)acrylate, t-butylaminoethyl (meth)acrylate. Epoxy group-containing monomers: for example, glycidyl (meth)acrylate, methyl glycidyl (meth)acrylate, allyl glycidyl ether. Cyano group-containing monomers: for example, acrylonitrile, methacrylonitrile. Keto group-containing monomers: for example, diacetone (meth)acrylamide, diacetone (meth)acrylate, vinyl methyl ketone, vinyl ethyl ketone, allyl acetoacetate, vinyl acetoacetate. Monomers having a nitrogen atom-containing ring: for example, N-vinyl-2-pyrrolidone, N-methylvinylpyrrolidone, N-vinylpyridine, N-vinylpiperidone, N-vinylpyrimidine, N-vinylpiperazine, N-vinylpyrazine, N-vinylpyrrole, N-vinylimidazole, N-vinyloxazole, N-vinylmorpholine, N-vinylcaprolactam, and N-(meth)acryloylmorpholine.

[0055] When the monomer component constituting the acrylic polymer contains the functional group-containing monomer described above, the content of the functional group-containing monomer in the monomer component is not particularly limited. From the viewpoint of properly achieving the effects of using the functional group-containing monomer, the content of the functional group-containing monomer in the monomer component can be, for example, 0.1% by mass or more, typically 0.5% by mass or more, and may be 1% by mass or more. Furthermore, from the viewpoint of easily balancing the adhesive performance, typically 40% by mass or less is suitable, preferably 20% by mass or less, and may be 10% by mass or less (e.g., 5% by mass or less). The technology disclosed herein can also be preferably implemented in an embodiment in which the monomer component is substantially free of functional group-containing monomers (e.g., an embodiment in which the monomer component is substantially composed only of alkyl (meth)acrylate and carboxy group-containing monomer). Here, "substantially free of functional group-containing monomers" means that functional group-containing monomers are not used at least intentionally, and for example, the unintentional inclusion of functional group-containing monomers at 0.05% by mass or less (typically 0.01% by mass or less) is acceptable.

[0056] The monomer components constituting the acrylic polymer may contain copolymerization components other than the above-mentioned monomers. Examples of the copolymerization components include vinyl ester monomers such as vinyl acetate, vinyl propionate, and vinyl laurate; aromatic vinyl compounds such as styrene, substituted styrenes (α-methylstyrene, etc.), and vinyltoluene; cycloalkyl(meth)acrylates such as cyclohexyl(meth)acrylate, cyclopentyl(meth)acrylate, and isobornyl(meth)acrylate; and aromatic ring-containing (meth)acrylates such as aryl(meth)acrylates (e.g., phenyl(meth)acrylate), aryloxyalkyl(meth)acrylates (e.g., phenoxyethyl(meth)acrylate), and arylalkyl(meth)acrylates (e.g., benzyl(meth)acrylate). olefin-based monomers such as ethylene, propylene, isoprene, butadiene, and isobutylene; chlorine-containing monomers such as vinyl chloride and vinylidene chloride; isocyanate group-containing monomers such as 2-(meth)acryloyloxyethyl isocyanate; alkoxy group-containing monomers such as methoxyethyl (meth)acrylate and ethoxyethyl (meth)acrylate; vinyl ether-based monomers such as methyl vinyl ether and ethyl vinyl ether; polyfunctional monomers having two or more (e.g., three or more) polymerizable functional groups (e.g., (meth)acryloyl groups) in one molecule, such as 1,6-hexanediol di(meth)acrylate and trimethylolpropane tri(meth)acrylate; and the like.

[0057] The amount of such other copolymerization components can be appropriately selected depending on the purpose and application, and is not particularly limited. From the viewpoint of properly exerting the effects of use, it is usually appropriate to set it to 0.05% by mass or more, and it may be 0.5% by mass or more. Furthermore, from the viewpoint of easily balancing adhesive performance, the content of other copolymerization components in the monomer component is usually appropriate to set it to 20% by mass or less, and it may be 10% by mass or less (e.g., 5% by mass or less). In this embodiment, an embodiment in which the monomer component is substantially free of other copolymerization components can also be preferably implemented. Here, "substantially free of other copolymerization components" means that other copolymerization components are not used at least intentionally, and it is acceptable for other copolymerization components to be unintentionally included, for example, at 0.01% by mass or less.

[0058] The tensile modulus of the base polymer (E ｐ ) is preferably 0.1 MPa or more, more preferably 0.2 MPa or more, and even more preferably 0.25 MPa or more. ｐ ) is preferably 3 MPa or less, more preferably 2.5 MPa or less, and even more preferably 2 MPa or less.

[0059] The tensile modulus of the base polymer (E ｐ ) can be determined, for example, as follows: First, the storage modulus (G ｐ Next, the tensile modulus (E ｐ ) is calculated. ｐ = E ｐ / 2(1+v) (1) In the above formula (1), v is the Poisson's ratio of the base polymer, which is set to 0.5 in this specification. More specifically, it can be measured by the method described in the examples below.

[0060] In an embodiment of the present invention, the base polymer can be obtained by (co)polymerizing monomer components. The polymerization method is not particularly limited, but examples thereof include solution polymerization, emulsion polymerization, bulk polymerization, suspension polymerization, and photopolymerization (active energy ray polymerization). When copolymerized, the base polymer may be any of a random copolymer, a block copolymer, an alternating copolymer, a graft copolymer, and the like.

[0061] In the emulsion polymerization method, the raw material monomers (monomer mixture) can be emulsion polymerized using an emulsifier and a polymerization initiator.

[0062] A reactive emulsifier having a polymerizable group (hereinafter referred to as a "reactive emulsifier" or sometimes referred to as a "reactive surfactant") can also be used as the emulsifier. Use of a reactive emulsifier is preferred because the emulsifier is incorporated into the base polymer, reducing contamination caused by the emulsifier.

[0063] Examples of the reactive emulsifier include anionic emulsifiers, nonionic emulsifiers, and cationic emulsifiers to which a radically polymerizable functional group such as a vinyl group, a propenyl group, an isopropenyl group, a vinyl ether group, or an allyl ether group has been introduced. Specific examples include polyoxyethylene styrenated propenyl phenyl ether sulfate ammonium, polyoxyethylene-1-(allyloxymethyl) alkyl ether sulfate ammonium, polyoxyethylene styrenated propenyl phenyl ether, polyoxyethylene-1-(allyloxymethyl) alkyl ether, and ammonium-α-sulfonato-ω-1-(allyloxymethyl) alkyloxy polyoxyethylene. When a reactive emulsifier is used, the base polymer obtained by emulsion polymerization contains monomer units derived from the reactive emulsifier.

[0064] As the reactive emulsifier, for example, commercially available products such as those under the trade name "ADEKA REASOAP SE-10N" (manufactured by ADEKA Corporation), those under the trade name "AQUALON HS-10" (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.), those under the trade name "AQUALON HS-05" (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.), those under the trade name "AQUALON HS-1025" (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.), those under the trade name "AQUALON KH-1025" (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.), and those under the trade name "AQUALON AR-10" (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) can also be used.

[0065] The amount of the reactive emulsifier blended (used) is preferably 0.1 to 10 parts by mass, more preferably 0.5 to 6 parts by mass, and even more preferably 1 to 4 parts by mass, per 100 parts by mass of the total amount of raw material monomers constituting the base polymer (all raw material monomers).

[0066] The polymerization initiator is not particularly limited, and polymerization initiators generally used in emulsion polymerization, such as azo-based polymerization initiators, peroxide-based polymerization initiators, and redox-based polymerization initiators, can be used.

[0067] The base polymer is preferably a polymer polymerized using a chain transfer agent. Examples of the chain transfer agent that can be preferably used include terpene compounds such as α-pinene, β-pinene, limonene, and terpinolene. Compounds having a thiol group or a hydroxyl group are also commonly known.

[0068] Examples of the compound having a thiol group include mercaptans such as lauryl mercaptan, 2-mercaptoethyl alcohol, t-dodecyl mercaptan, and mercaptosuccinic acid, alkyl mercaptopropionates such as n-butyl mercaptopropionate and octyl mercaptopropionate, and alkoxyalkyl mercaptopropionates such as methoxybutyl mercaptopropionate, etc. Examples of the compound having a hydroxyl group include alcohols such as methyl alcohol, n-propyl alcohol, isopropyl alcohol (IPA), t-butyl alcohol, and benzyl alcohol.

[0069] The amount of the chain transfer agent used is preferably 0 to 1 part by mass per 100 parts by mass of the total amount of raw material monomers used in emulsion polymerization (all raw material monomers). By using an amount of 1 part by mass or less, it is possible to prevent a decrease in water resistance, heat resistance, etc. due to a decrease in molecular weight, and to prevent the problem of guide roll contamination from occurring, which is preferable.

[0070] The emulsion polymerization of the base polymer can be carried out by emulsifying the monomer components in an aqueous medium using a conventional method, followed by emulsion polymerization, thereby preparing an aqueous dispersion (polymer emulsion) containing the base polymer.

[0071] (Air Bubbles) The pressure-sensitive adhesive of the present embodiment contains air bubbles. In this specification, the air bubbles contained in the pressure-sensitive adhesive refer to minute voids present in the pressure-sensitive adhesive.

[0072] Although the reason for the superior adhesive strength of the thread-like adhesive body according to this embodiment is unclear, it is presumed that the adhesive containing bubbles makes it easier for the adhesive around the bubbles to deform when stress is applied to the thread-like adhesive body, dispersing the stress and improving adhesive strength. More specifically, when a force is applied to peel the thread-like adhesive body adhered to an adherend, stress concentrates at specific locations in the adhesive. The presence of tiny bubbles at these stress-concentrating locations makes it easier for the adhesive to deform in the tensile direction. It is presumed that the high adhesive strength is achieved as a result of the stress being dispersed by stretching the adhesive in this way.

[0073] The size of the bubbles may be, for example, 20 μm or less, 15 μm or less, or 10 μm or less in diameter, and the lower limit may be, for example, 0.5 μm or more, 1 μm or more, or 5 μm or more.

[0074] The content of bubbles having a diameter of 20 μm or less in the pressure-sensitive adhesive is preferably greater than 0 vol%, more preferably 0.5 vol% or more, even more preferably 1.0 vol% or more, particularly preferably 1.5 vol% or more, and most preferably 2.0 vol% or more. Even a small amount of bubbles contained in the pressure-sensitive adhesive makes it easier to achieve the effect of improving the adhesive strength of the thread-like adhesive body. Furthermore, the content of bubbles is preferably 10 vol% or less, more preferably 5 vol% or less. By setting the content of bubbles to 10 vol% or less, it is easier to suppress a decrease in the bulk strength of the pressure-sensitive adhesive. The content of bubbles is preferably greater than 0 vol% and less than 10 vol%, more preferably greater than 0 vol% and less than 5 vol%, and even more preferably 2 vol% or more and less than 5 vol%.

[0075] The size and content of bubbles in the PSA can be measured, for example, from images obtained using a scanning electron microscope or an X-ray CT scanner. More specifically, they can be measured by the method described in the Examples below.

[0076] It is preferable that the bubbles are not present on the surface of the adhesive (the surface of the thread-like adhesive body) but are present inside the adhesive, particularly in the vicinity of the core material. By having the bubbles present inside the adhesive rather than on the surface, a decrease in the adhesive strength of the adhesive can be suppressed.

[0077] The means for incorporating bubbles into the adhesive is not particularly limited. For example, when producing the thread-like adhesive body according to this embodiment, bubbles can be incorporated into the adhesive by applying a coating liquid containing the base polymer and the particles described below to a core material and drying the coating liquid to form an adhesive on the surface of the core material. Furthermore, bubbles can be incorporated near the core material rather than on the surface of the adhesive. This is presumably because, when drying shrinkage occurs due to the evaporation of the solvent or dispersion medium contained in the coating liquid during the drying process of the coating liquid, minute voids are more likely to occur due to the difference in shrinkage rate between the base polymer and the particles.

[0078] (Particles) The pressure-sensitive adhesive in this embodiment further contains particles, and the tensile modulus of the particles is preferably 30 times or more that of the base polymer. It is presumed that the pressure-sensitive adhesive contains particles with a relatively higher tensile modulus than the base polymer, which further promotes stress dispersion when stress is applied to the thread-like adhesive body, thereby further improving adhesive strength. Furthermore, as described above, by applying a coating liquid containing the base polymer and the particles to a core material and drying it to form a pressure-sensitive adhesive on the surface of the core material, air bubbles can be incorporated into the pressure-sensitive adhesive. Only one type of the above particles may be used, or two or more types may be used.

[0079] The tensile modulus of the particles (E ｆ ') is the tensile modulus of the base polymer (E ｐ From the viewpoint of improving the adhesive strength by improving the stress dispersion effect, the ratio is preferably 30 times or more, and from the viewpoint of improving the adhesive strength by improving the stress dispersion effect, the ratio is preferably 100 times or more, more preferably 300 times or more, and may be 500 times or more, 800 times or more, or may be 1000 times or more. The upper limit can be, for example, 1500 times or less, from the viewpoint of improving the dispersibility of particles in the pressure-sensitive adhesive.

[0080] The tensile modulus of the particles (E ｆ The tensile modulus (E ｆ The tensile modulus (E ｆ Preferably, the modulus is 0.01 to 3 GPa.

[0081] The tensile modulus of the particles (E ｆ The thickness (%) can be measured, for example, using a nanoindenter. More specifically, it can be measured by the method described in the Examples below.

[0082] The average particle size of the particles is preferably 0.05 μm or more, more preferably 0.075 μm or more, and even more preferably 0.1 μm or more. From the viewpoint of manufacturability and appearance of the thread-like adhesive body, the upper limit of the average particle size of the particles is preferably 35 μm or less, more preferably 25 μm or less, even more preferably 15 μm or less, particularly preferably 10 μm or less, and most preferably 5 μm or less. The average particle size of the particles is preferably 0.05 μm to 35 μm. The average particle size is the median diameter (D50) measured by dynamic light scattering. When the adhesive according to the embodiment of the present invention contains two or more types of particles, the average particle size of the particles is the average particle size of all the particles.

[0083] The particles may be either organic or inorganic. Examples of materials constituting the inorganic material include metals such as copper, silver, gold, platinum, nickel, aluminum, chromium, iron, and stainless steel; metal oxides such as aluminum oxide, silicon oxide (silicon dioxide), titanium oxide, zirconium oxide, zinc oxide, tin oxide, copper oxide, and nickel oxide; aluminum hydroxide, boehmite, magnesium hydroxide, calcium hydroxide, zinc hydroxide, silicic acid, iron hydroxide, copper hydroxide, barium hydroxide, zirconium oxide hydrate, tin oxide hydrate, basic magnesium carbonate, and hydrotalcite. carbides such as silicon carbide, boron carbide, nitrogen carbide, calcium carbide; nitrides such as aluminum nitride, silicon nitride, boron nitride, gallium nitride; carbonates such as calcium carbonate; titanates such as barium titanate, potassium titanate; carbon-based substances such as carbon black, carbon tubes (carbon nanotubes), carbon fiber, diamond; inorganic materials such as glass; and natural raw material particles such as volcanic silt, clay, and sand.

[0084] Examples of materials constituting the organic matter include polymers such as polystyrene, acrylic resin (e.g., polymethyl methacrylate), phenol resin, benzoguanamine resin, urea resin, silicone resin, polyester, polyurethane, polyethylene, polypropylene, polyamide (e.g., nylon), polyimide, and polyvinylidene chloride. Rubber-based resins such as natural rubber and synthetic rubber may also be used.

[0085] Among the above particles, particles made of organic materials are preferred, particles made of polyethylene, polyamide, acrylonitrile butadiene rubber, acrylic resin, styrene butadiene rubber, or polystyrene are more preferred, and particles made of polyethylene or polyamide are even more preferred.

[0086] In the pressure-sensitive adhesive according to an embodiment of the present invention, the particle content is preferably 5 parts by mass or more, more preferably 8 parts by mass or more, and even more preferably 10 parts by mass or more, per 100 parts by mass of the base polymer. By setting the particle content at 10 parts by mass or more, it is easy to obtain an effect of improving adhesive strength by improving the stress dispersion effect. Furthermore, the particle content is preferably 65 parts by mass or less, more preferably 63 parts by mass or less, and even more preferably 60 parts by mass or less, per 100 parts by mass of the base polymer. By setting the particle content at 60 parts by mass or less, it is easy to suppress a decrease in adhesive strength. In the pressure-sensitive adhesive according to an embodiment of the present invention, it is preferable that the particle content be 10 to 60 parts by mass, per 100 parts by mass of the base polymer.

[0087] In addition to the base polymer, bubbles, and particles, the adhesive may contain various additives, such as a tackifying resin, a crosslinking agent, a viscosity modifier (such as a thickener), a leveling agent, a release modifier, a plasticizer, a softener, a filler, a colorant (such as a pigment or dye), a surfactant, an antistatic agent, a preservative, an antioxidant, an ultraviolet absorber, an antioxidant, and a light stabilizer.

[0088] It is preferable to blend a crosslinking agent into the acrylic pressure-sensitive adhesive. The crosslinking agent used in the acrylic pressure-sensitive adhesive can be a commonly used crosslinking agent, such as a silane-based crosslinking agent, an organic peroxide, an epoxy-based compound, an amino group-containing compound, an organic metal salt, a metal alcoholate, a metal chelate, a hydrazide-based crosslinking agent, a carbodiimide-based crosslinking agent, an isocyanate-based crosslinking agent, or a silanol-based crosslinking agent. Among these, organic metal salts, metal chelates, hydrazide-based crosslinking agents, and silane-based crosslinking agents are preferred because they rapidly complete crosslinking after the pressure-sensitive adhesive composition is dried. In the case of a water-dispersible pressure-sensitive adhesive, hydrazide-based crosslinking agents and silane-based crosslinking agents are particularly preferred. The crosslinking agent may be either oil-soluble or water-soluble, and may be used alone or in combination of two or more.

[0089] As the silane crosslinking agent, it is preferable to use a silane monomer copolymerizable with the (meth)acrylic acid alkyl ester. The silane monomer is not particularly limited as long as it is a polymerizable compound having a silicon atom. However, silane compounds having a (meth)acryloyl group, such as (meth)acryloyloxyalkylsilane derivatives, are preferred because of their excellent copolymerizability with the (meth)acrylic acid alkyl ester. Examples of silane monomers include γ-methacryloxypropyltrimethoxysilane, 3-acryloyloxypropyltrimethoxysilane, 3-methacryloyloxypropyltriethoxysilane, 3-acryloyloxypropyltriethoxysilane, 3-methacryloyloxypropylmethyldimethoxysilane, 3-acryloyloxypropylmethyldimethoxysilane, 3-methacryloyloxypropylmethyldiethoxysilane, and 3-acryloyloxypropylmethyldiethoxysilane. These silane monomers can be used alone or in combination of two or more.

[0090] In addition to the above, examples of copolymerizable silane monomers that can be used include vinyltrimethoxysilane, vinyltriethoxysilane, 4-vinylbutyltrimethoxysilane, 4-vinylbutyltriethoxysilane, 8-vinyloctyltrimethoxysilane, 8-vinyloctyltriethoxysilane, 10-methacryloyloxydecyltrimethoxysilane, 10-acryloyloxydecyltrimethoxysilane, 10-methacryloyloxydecyltriethoxysilane, and 10-acryloyloxydecyltriethoxysilane.

[0091] The amount of the crosslinking agent used can be appropriately selected depending on the type of the monomer raw material, the application of the adhesive article, etc. In this embodiment, the amount of the crosslinking agent relative to 100 parts by mass of the monomer raw material (excluding the crosslinking agent) is preferably 0.005 to 5 parts by mass, and more preferably 0.01 to 3 parts by mass.

[0092] In this embodiment, other crosslinking agents may also be used, and crosslinking using other crosslinking agents, UV crosslinking, radiation crosslinking such as electron beam crosslinking, etc. may be applied. As the other crosslinking agent, a commonly used crosslinking agent may be used, and examples thereof include organic peroxides, epoxy compounds, amino group-containing compounds, organic metal salts, metal alcoholates, metal chelates, hydrazide crosslinking agents, carbodiimide crosslinking agents, isocyanate crosslinking agents, and silane or silanol crosslinking agents. The other crosslinking agent may be either oil-soluble or water-soluble.

[0093] Any appropriate tackifying resin can be used as the tackifying resin. Specific examples of the tackifying resin include rosin-based tackifying resins (e.g., unmodified rosin, modified rosin, rosin phenolic resins, rosin ester resins, etc.), terpene-based tackifying resins (e.g., terpene resins, terpene phenolic resins, styrene-modified terpene resins, aromatic-modified terpene resins, hydrogenated terpene resins), hydrocarbon-based tackifying resins (e.g., aliphatic hydrocarbon resins, aliphatic cyclic hydrocarbon resins, aromatic hydrocarbon resins (e.g., styrene-based resins, xylene-based resins, etc.), aliphatic / aromatic petroleum resins, aliphatic / alicyclic petroleum resins, hydrogenated hydrocarbon resins, coumarone-based resins, coumarone-indene resins, etc.), phenol-based tackifying resins (e.g., alkylphenol-based resins, xylene-formaldehyde-based resins, resols, novolacs, etc.), ketone-based tackifying resins, polyamide-based tackifying resins, epoxy-based tackifying resins, and elastomer-based tackifying resins. Among these, rosin-based tackifying resins, terpene-based tackifying resins, and hydrocarbon-based tackifying resins (such as styrene-based resins) are preferred. The tackifying resins may be used alone or in combination of two or more.

[0094] In an embodiment in which the PSA contains a tackifier resin, the amount of the tackifier resin added is preferably 1 part by mass or more, more preferably 10 parts by mass or more, even more preferably 20 parts by mass or more, and even more preferably 30 parts by mass or more, relative to 100 parts by mass of the base polymer. From the viewpoint of suppressing a decrease in the adhesive strength of the PSA, the amount is preferably 100 parts by mass or less, more preferably 90 parts by mass or less, and even more preferably 70 parts by mass or less.

[0095] The PSA composition forming the PSA contains a base polymer and a tackifier resin, and preferably contains 1 to 100 parts by mass of the tackifier resin per 100 parts by mass of the base polymer. More preferably, it contains a base polymer, particles, and a tackifier resin, and preferably contains 10 to 60 parts by mass of the particles and 1 to 100 parts by mass of the tackifier resin per 100 parts by mass of the base polymer. Here, the PSA composition forming the PSA may contain bubbles, but the PSA composition does not have to contain bubbles as long as the PSA formed contains bubbles.

[0096] The PSA composition may be either a solvent-based PSA or a water-dispersed PSA, but a water-dispersed PSA composition is preferred because it allows high-speed coating, is environmentally friendly, and has minimal effects (swelling, dissolution) on the core material due to the solvent.

[0097] Specifically, the adhesive amount (mass of adhesive per unit length) is preferably 2 mg / m or more, more preferably 5 mg / m or more, and even more preferably 8 mg / m or more. On the other hand, if the adhesive amount is excessive, the adhesive composition needs to be applied to the core material multiple times in the manufacturing process, and the applied adhesive composition takes a long time to dry, resulting in low manufacturing efficiency. Therefore, the adhesive amount is preferably 200 mg / m or less, more preferably 180 mg / m or less, and even more preferably 160 mg / m or less.

[0098] The content of the adhesive in the thread-like adhesive body is preferably 10% by mass or more, more preferably 20% by mass or more, and particularly preferably 30% by mass or more, from the viewpoint of increasing the coverage rate of the core material, and the content of the adhesive in the thread-like adhesive body is preferably 90% by mass or less, more preferably 80% by mass or less, and particularly preferably 70% by mass or less, from the viewpoint of suppressing a decrease in the strength of the thread-like adhesive body.

[0099] In this embodiment, the thread width of the thread-like adhesive body is preferably 50 to 2000 μm, more preferably 100 to 1000 μm, from the viewpoint of strength and ease of handling.

[0100] In the present embodiment, the adhesive strength of the thread-like adhesive body is preferably increased by heating it for 1 hour at a temperature of 40° C. or higher and 80° C. or lower. From the viewpoint of improving the adhesive strength after heating, the heating temperature is preferably 50° C. or higher and 70° C. or lower, and more preferably 55° C. or higher and 65° C. or lower.

[0101] When adherends are fixed together using a thread-like adhesive whose adhesive strength increases with heat aging, it is possible to further improve the adhesive strength by, for example, performing heat aging after bonding the adherends together.

[0102] To obtain a thread-like adhesive body whose adhesive strength improves upon heat aging, for example, an adhesive agent containing the above-mentioned particles may be used, and the type and content of the particles may be within the above-mentioned preferred ranges.

[0103] The heating method is not particularly limited, but for example, the thread-like adhesive body may be placed in a dryer set to a heating temperature while adhered to the adherend, and aged.

[0104] Although the detailed mechanism by which heat aging improves the adhesive strength of the thread-like adhesive is unclear, it is presumed that heat aging increases the number of air bubbles contained in the adhesive, thereby increasing the stress transmission paths within the adhesive.

[0105] [Method for manufacturing a thread-like adhesive body] The thread-like adhesive body according to an embodiment of the present invention can be manufactured by a known method, for example, by a method including a coating step of applying a coating liquid that forms an adhesive to a core material.

[0106] The coating liquid may be applied to the core material by, for example, dipping, immersion, or coating, and may be dried by heating as necessary. The drying by heating may be carried out, for example, at a temperature of 80 to 120°C, preferably 90 to 110°C, for example, for 20 seconds to 3 minutes, preferably 30 seconds to 2 minutes.

[0107] The coating liquid can be applied using a conventional coater such as a gravure roll coater, a reverse roll coater, a kiss roll coater, a dip roll coater, a bar coater, a knife coater, or a spray coater.

[0108] As long as the PSA to be formed contains bubbles, the coating liquid may not contain bubbles. For example, a PSA containing bubbles may be formed by using a coating liquid containing the above-mentioned base polymer and particles but not containing bubbles, and applying the coating liquid to a core material and drying the coating liquid.

[0109] The method for producing a thread-like adhesive body according to an embodiment of the present invention preferably includes a coating step of applying a coating liquid containing the above-mentioned base polymer and particles to the above-mentioned core material, and a drying step of drying the applied coating liquid.

[0110] The method for producing a thread-like adhesive body of this embodiment may or may not include a fiber-opening step, in which the core material is opened by running the core material along a non-rotating roller when the adhesive is applied to the core material.

[0111] Furthermore, when the method for producing a thread-like adhesive material of this embodiment includes a coating step, it is preferable that a roller is used in the coating step, and the rotation speed of the roller is 0.3 to 5.0 times the payout speed of the core material. By keeping the rotation speed of the roller within the above range, it is possible to prevent the core material from opening.

[0112] The rotation speed of the roller is more preferably 0.4 to 4.0 times the core material payout speed, further preferably 0.5 to 3.0 times, and particularly preferably 0.8 to 1.5 times.

[0113] In addition, it is preferable to apply a tension of 6.0 mN / dtex or less to the core material in the coating step. By applying a tension of 6.0 mN / dtex or less to the core material, it is possible to prevent the core material from opening.

[0114] The tension applied to the core material is preferably 0.2 to 6.0 mN / dtex, more preferably 0.4 to 5.0 mN / dtex.

[0115] [Uses of adhesive threads] The adhesive threads according to the embodiments of the present invention can be attached to narrow members or narrow areas while suppressing overflow, can be easily applied to complex shapes such as curves, curved surfaces, and uneven surfaces, and are also preferred in that they can be easily disassembled (reworked). Furthermore, due to their excellent adhesive strength, they can be used to adhere various articles. For example, the adhesive threads according to the embodiments of the present invention can be suitably used for fixing articles in the manufacture of electronic devices and for fixing in-vehicle components, and can be particularly applied to fixing housings / components of medium- to large-sized home appliances such as television and display housings.

[0116] Furthermore, for example, when an adhesive tape is applied to an adherend having a complex shape such as a curve, a curved surface, or an uneven surface, wrinkles and overlaps occur in the adhesive tape in those areas, making it difficult to apply the tape neatly while preventing overhang. Furthermore, the wrinkles and overlaps may also cause a decrease in adhesive strength. To apply the adhesive tape without wrinkles or overlaps, it is possible to cut the adhesive tape into small pieces before application, but this significantly reduces workability. On the other hand, the adhesive thread according to the embodiment of the present invention can be firmly applied without wrinkles or overlaps even when applied to a complex shape such as a curve, a curved surface, or an uneven surface. Furthermore, since the adhesive thread can be applied to the desired area all at once, i.e., in a single process, it is highly efficient and can be applied to automated lines.

[0117] Specifically, the thread-like adhesive material according to an embodiment of the present invention can be suitably used for fixing, in a desired shape, cables such as electric wires and optical fibers, LED fiber lights, optical fiber sensors such as FBGs (Fiber Bragg Gratings), various wires (linear members) such as threads, strings, and wires, and thin members.

[0118] Even when fixing a wire or a narrow member having a complex shape to another member, the adhesive thread according to the embodiment of the present invention can be used to firmly fix the wire or narrow member with excellent workability while suppressing protrusion, wrinkles, and overlaps, in accordance with the complex shape of the wire or narrow member. When fixing a wire or narrow member to another member, the adhesive thread according to the embodiment of the present invention can be attached in advance to the surface of the other member in accordance with the shape to which the wire or narrow member is to be fixed, and then the wire or narrow member can be attached to the adhesive thread attached to the surface of the other member. Alternatively, the adhesive thread according to the embodiment of the present invention can be attached to the wire or narrow member, and then the wire or narrow member can be fixed to the other member in the desired shape.

[0119] Furthermore, the thread-like adhesive material according to the embodiment of the present invention can also be suitably used for the purpose of temporarily fixing (temporarily fastening) an article to the surface of another article. More specifically, the thread-like adhesive material according to the embodiment of the present invention can be used for the purpose of temporarily fixing (temporarily fastening) an article to the surface of another article, for example, when manufacturing textile products such as clothing, shoes, bags, and hats, or leather products. However, the use is not limited thereto, and the thread-like adhesive material according to the embodiment of the present invention can be suitably used for various applications in which temporary fixing (temporarily fastening) is desired. For example, when fixing an article to the surface of another article, the article is temporarily fixed to the surface of the other article using the thread-like adhesive material in advance to position the article, and then the two articles are fixed (mainly fixed) by a fixing method such as thermocompression bonding or sewing. In this case, the thread-like adhesive material according to the embodiment of the present invention can easily be used to temporarily fix the two articles while avoiding the fixing portion provided between the two articles. For example, when sewing textile products or leather products, temporary fixing using the thread-like adhesive material makes it easy to temporarily fix the articles while avoiding the sewing portion, and can easily prevent the adhesive from adhering to the needle.

[0120] Furthermore, as described above, the adhesive thread according to the embodiment of the present invention can be used to successfully bond both articles, even if they have complex shapes such as curves, curved surfaces, or uneven surfaces, while minimizing overflow, wrinkles, and overlaps. Furthermore, the adhesive thread according to the embodiment of the present invention can be bonded in a single step, resulting in excellent workability. Furthermore, even for easily deformable materials such as fabrics, cloth, and leather that make up textile or leather products, temporary fixation using the adhesive thread according to the embodiment of the present invention can suppress or prevent deformation of the materials due to tension, resulting in excellent design after fixation (full fixation). Furthermore, the adhesive thread according to the embodiment of the present invention can be easily removed from between the two articles after fixation (full fixation) of the two articles, as needed. This prevents overflow of the adhesive and effectively prevents deterioration of the design due to discoloration of the remaining adhesive over time. Furthermore, the adhesive thread according to the embodiment of the present invention can be used as a dam material to prevent overflow of the adhesive or adhesive when applying the adhesive or adhesive to the object to be bonded (adherend). The dam material can be used, for example, to prevent the extrusion of sealing resin used in bonding optical panels. When using the adhesive threads as the dam material, the adhesive threads may be peeled off after the adhesive or pressure-sensitive adhesive has hardened, or may be left in place.

[0121] Furthermore, the thread-like adhesive material according to the embodiment of the present invention can be twisted together with threads made of other materials to form combined threads, or woven with threads or fabrics (including nonwoven fabrics and sheets) made of other materials to achieve a combination of functions.

[0122] [Laminate] The present invention also relates to a laminate of the above-mentioned thread-like adhesive material and an electronic device member. Examples of electronic device members include narrow bezels of mobile terminals such as mobile phones and smartphones, notebook PCs, earphones, headphones, speakers, thin displays, game consoles, digital cameras, electronic dictionaries, cables such as electric wires and optical fibers, LED fiber lights, and optical fiber sensors such as FBG. The laminate according to an embodiment of the present invention may be a bonded body in which multiple electronic device members are bonded together with a thread-like adhesive material.

[0123] As described above, the present specification discloses the following. <1> A thread-like adhesive body comprising a core material and a pressure-sensitive adhesive coating the longitudinal surface of the core material, the pressure-sensitive adhesive containing a base polymer and air bubbles. <2> The thread-like adhesive body according to <1>, wherein the pressure-sensitive adhesive further contains particles, the tensile modulus of the particles being at least 30 times that of the base polymer. <3> The thread-like adhesive body according to <2>, wherein the tensile modulus of the particles is 0.01 to 3 GPa. <4> The thread-like adhesive body according to <2>, wherein the particles are contained in an amount of 10 to 60 parts by mass per 100 parts by mass of the base polymer. <5> The thread-like adhesive body according to any one of <1> to <4>, wherein the pressure-sensitive adhesive contains more than 0% by volume and not more than 5% by volume of air bubbles having a diameter of 20 μm or less. <6> The thread-like adhesive body according to any one of <1> to <5>, wherein the adhesive exhibits increased adhesive strength when heated at 40°C or higher and 80°C or lower for 1 hour. <7> The thread-like adhesive material according to <1>, wherein the core material is a multifilament yarn. <8> A laminate of the thread-like adhesive material according to any one of <1> to <7> and an electronic device member.

[0124] The present invention will be explained in more detail below by way of examples, but the present invention is not limited to the following examples in any way.

[0125] <Preparation of Acrylic Polymer Emulsion> (Preparation of Acrylic Polymer Emulsion 1) To a reaction vessel equipped with a thermometer, a stirrer, a nitrogen inlet tube, and a reflux condenser, 0.07 parts by mass of a reactive surfactant (Aqualon KH-1025 / manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) and 61.1 parts by mass of distilled water were added, and the atmosphere was replaced with nitrogen at 60° C. for 1 hour with stirring. Thereafter, 0.10 parts by mass of a polymerization initiator (VA-057 / manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was added thereto. To this mixture, 85 parts by weight of 2-ethylhexyl acrylate (2EHA), 13 parts by weight of methyl acrylate (MA), 1.25 parts by weight of acrylic acid (AA), 0.75 parts by weight of methacrylic acid (MAA), 0.025 parts by weight of t-dodecanethiol (chain transfer agent), 0.02 parts by weight of 3-methacryloxypropyltrimethoxysilane (KBM-503), and 1.93 parts by weight of the reactive surfactant were emulsified in 28 parts by weight of distilled water, and the emulsion polymerization was allowed to proceed while gradually adding dropwise at 60°C over 4 hours. After maintaining the temperature at 60°C for 3 hours, 0.05 parts by weight of the polymerization initiator was added, and the mixture was further maintained at 60°C for 2 hours. The system was cooled to room temperature, the pH was adjusted to 7 using 10% aqueous ammonia as a pH adjuster, and 0.0072 parts by weight of a preservative (Neosintol 2208 / Sumika Enviroscience Co., Ltd.) was added. In this way, an aqueous dispersion of an acrylic polymer (acrylic polymer emulsion 1) was prepared. The solid content concentration of this acrylic polymer was 50.5% by mass, and the sol weight average molecular weight (Mw) was 340,000.

[0126] <Preparation of Pressure-Sensitive Adhesive Composition> (Preparation of Pressure-Sensitive Adhesive Composition 1) A tackifier resin emulsion (manufactured by Arakawa Chemical Industries, Ltd., trade name "Tamanol E200NT") was added so that the tackifier resin was 35 parts by mass per 100 parts by mass of the acrylic polymer contained in Acrylic Polymer Emulsion 1. Furthermore, 0.07 parts by mass of a silane coupling agent (manufactured by Shin-Etsu Chemical Co., Ltd., trade name "Z-6210") was added per 100 parts by mass of the acrylic polymer, and ion-exchanged water was added to dilute the solids concentration to 45% by mass. Then, 10% by mass of ammonia water as a pH adjuster and polyacrylic acid (manufactured by Toagosei Co., Ltd., trade name "Aron A-10H") as a thickener were used to adjust the pH and viscosity to be suitable for coating, thereby obtaining Pressure-Sensitive Adhesive Liquid 1. The amount of ammonia water added per 100 parts by mass of the acrylic polymer was 1.5 parts by mass, and the amount of polyacrylic acid added was 4 parts by mass.

[0127] To the adhesive liquid 1, polyamide particles (manufactured by Sumitomo Seika Chemicals Co., Ltd., product name "Sepolsion PA200") and distilled water were added so that the particles were 10 parts by mass per 100 parts by mass of the acrylic polymer, and the mixture was stirred at 1000 rpm for 5 minutes using a high-speed disper, and air bubbles were removed using a centrifugal defoamer, thereby obtaining an adhesive composition 1 having a solid content concentration of 34% by mass.

[0128] (Preparation of Pressure-Sensitive Adhesive Compositions 2 to 6) Pressure-Sensitive Adhesive Compositions 2 to 6 were obtained in the same manner as Pressure-Sensitive Adhesive Composition 1, except that the types and amounts of particles added were changed as shown in Table 1.

[0129] <Production of thread-like adhesive body> (Example 1) As a core material, a multifilament yarn (core material 1) was prepared by twisting 150 times per meter seven polyethylene terephthalate (PET) fibers (manufactured by Teijin Frontier Co., Ltd.) (fineness: 1169 dtex, number of filaments: 336) having a fineness of 167 dtex and a number of 48 filaments. The core material was coated with PSA composition 1 by dipping using a coating roller. The coating was then dried at 80°C for 5 minutes to obtain a thread-like adhesive body with a glue amount (adhesive amount) of 50 mg / m.

[0130] Examples 2 to 7, Comparative Example 1 Thread-like adhesive bodies were prepared in the same manner as in Example 1, except that the type of adhesive composition was changed as shown in Table 1.

[0131] <Tensile modulus of base polymer (E ｐ The acrylic polymer emulsion 1 obtained above was applied to a release liner and dried to produce a 20 μm thick pressure-sensitive adhesive layer (base polymer layer) on the release liner. A plurality of the obtained pressure-sensitive adhesive layers were stacked together to produce a pressure-sensitive adhesive layer with a thickness of approximately 2 mm. This pressure-sensitive adhesive layer was punched into a disk shape with a diameter of 7.9 mm, and the resulting sample was sandwiched and fixed between parallel plates. Dynamic viscoelasticity was measured under the following conditions using a viscoelasticity tester (trade name "ARES Rheometer", manufactured by T.A. Instruments) at 23°C and 50% RH. The storage modulus G ｐ ' (23°C) was calculated. It was confirmed that the peak top of tan δ was present in the range of -20 to 0°C. Measurement mode: Shear mode Temperature range: -70°C to 150°C Heating rate: 5°C / min Measurement frequency: 1 Hz

[0132] Next, the storage modulus (G ｐ '), and the tensile modulus of elasticity of the base polymer (E ｐ ') was calculated. ｐ '=E ｐ ' / 2(1+v) (1) In the above formula (1), v is the Poisson's ratio of the base polymer, which is set to 0.5 in this specification.

[0133] <Tensile modulus of the particles (E ｆ For the analytical samples, the particles used in the examples and comparative examples (all commercially available products were dispersions) were separated into the dispersion medium and particles using filter paper, dried, and the particles were fixed to a predetermined support to serve as measurement samples, and nanoindentation measurements were carried out. Apparatus: Triboindenter manufactured by Hysitron Inc. Indenter used: Berkovich (triangular pyramid) Measurement method: Single indentation measurement Measurement temperature: Room temperature (25°C) Indentation depth: 1500 nm

[0134] The tensile modulus (E ｐ '), the tensile modulus of the particles (E ｆ ') from E ｆ ' / E ｐ ' was calculated.

[0135] <Size and content of bubbles in adhesive> The cross sections of the obtained thread-like adhesive bodies of the Examples and Comparative Examples were observed using an X-ray CT scanner, and bubbles in the adhesive were extracted from the obtained observation images and the bubble sizes were measured. The bubble sizes were determined as diameters using the X-ray CT scanner. Table 1 shows the average diameters of bubbles with a diameter of 20 μm or less. Furthermore, using the above observation images, bubbles with a diameter of 20 μm or less in the adhesive were extracted and the content (volume %) in the adhesive was determined.

[0136] [Evaluation] The obtained thread-like adhesive material was evaluated as follows. The results are shown in Table 1.

[0137] <Cleavage Peel Force After Curing at Room Temperature> The filamentous adhesive bodies of the Examples and Comparative Examples were cut to 270 mm and attached to a 50 x 30 mm SUS304 plate in a spiral shape as shown in Figure 1. A 30 x 30 mm SUS jig was attached to the top and pressed at 178 N (1 MPa) for 10 seconds. After leaving the plate at room temperature (23°C) for 30 minutes, the plate was pulled vertically at a peel rate of 300 mm / min to measure the cleavage peel force. An autograph (SHIMADZU, AG-X / R AG-20kNG) was used for the measurement, and the number of samples was n = 3 or more. Table 1 shows the average values.

[0138] <Cleavage peel strength after heat aging> The SUS jig in which the filamentous adhesive bodies of the Examples and Comparative Examples were spirally bonded together using the same procedure as described above was placed in a low-temperature dryer set to each aging temperature shown in Table 1 and stored for 1 hour. After removal, it was left to cool at room temperature for 1 hour or more. Thereafter, the cleavage peel strength was measured according to the procedure described above.

[0139] The cleavage peel strength after heat aging and the cleavage peel strength after room temperature curing were compared to determine their ratio (cleavage peel strength after heat aging / cleavage peel strength after room temperature curing). Table 1 shows the peel strength ratio.

[0140] In Table 1 below, the column for base polymer shows the type and amount (parts by mass) of each monomer constituting the base polymer.

[0141]

[0142] The particles shown in Table 1 are as follows: PA200: manufactured by Sumitomo Seika Chemicals Co., Ltd., trade name "Sepolsion PA200", particle size 0.5 μm, polyamide filler AC: manufactured by Sumitomo Seika Chemicals Co., Ltd., trade name "Zaixen AC", particle size 0.14 μm, polyethylene filler 1571H: manufactured by Nippon Zeon Co., Ltd., trade name "Nipol 1571H", particle size 0.13 μm, acrylonitrile butadiene rubber (NBR) filler

[0143] The results shown in Table 1 demonstrate that the adhesive threads of Examples 1 to 7 have particularly excellent adhesive strength. Furthermore, because the adhesive threads have a core material, they also have excellent dismantling properties. In contrast, the adhesive thread of Comparative Example 1, which does not contain bubbles in the adhesive layer, has poor adhesive strength.

[0144] <Changes in bubbles in the adhesive before and after heat aging> The cross section of the thread-like adhesive of Example 4 was observed using an X-ray CT scanner, and bubbles in the adhesive were extracted from the obtained observation image and the bubble size was measured. The bubble size was determined as the diameter of a sphere inscribed in the void. Table 2 shows the average diameter of bubbles with a diameter of 20 μm or less. In addition, using the above observation image, bubbles with a diameter of 20 μm or less were extracted and counted. The thread-like adhesive of Example 4 was placed in a low-temperature dryer set at 60°C and stored for 1 hour, after which the same observation was made and the size and number of bubbles in the adhesive were measured. Table 2 shows the measurement results per 2.7 mm length of the thread-like adhesive.

[0145]

[0146] Table 2 shows that heat aging of the filamentous adhesive body increases the number of bubbles with a diameter of 20 μm or less. In addition, since the average bubble size is slightly smaller after heat aging, it is thought that the number of relatively small bubbles is increasing.

[0147] In this way, it is believed that the adhesive strength (cleavage peel strength) of the thread-like adhesive body according to an embodiment of the present invention is improved as shown in Table 1 because the number of small bubbles increases upon heat aging.

[0148] The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention.

[0149] According to the present invention, an adhesive material having high adhesive strength and easy dismantling properties can be provided.

[0150] Although the present invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the present invention. This application is based on a Japanese patent application (Patent Application No. 2024-057293) filed on March 29, 2024, the contents of which are incorporated herein by reference.

Claims

1. A thread-like adhesive body comprising a core material and an adhesive that coats the longitudinal surface of the core material, the adhesive containing a base polymer and air bubbles.

2. The thread-like adhesive body according to claim 1, wherein the adhesive further comprises particles, and the tensile modulus of the particles is 30 times or more the tensile modulus of the base polymer.

3. The thread-like adhesive body according to claim 2, wherein the particles have a tensile modulus of elasticity of 0.01 to 3 GPa.

4. The thread-like adhesive body according to claim 2, comprising 10 to 60 parts by mass of the particles per 100 parts by mass of the base polymer.

5. The thread-like adhesive body according to claim 1, wherein the adhesive contains more than 0% by volume and not more than 5% by volume of bubbles with a diameter of 20 μm or less.

6. The thread-like adhesive material according to claim 1, the adhesive strength of which increases when heated at 40°C or higher and 80°C or lower for 1 hour.

7. The thread-like adhesive body according to claim 1, wherein the core material is a multifilament thread.

8. A laminate of the thread-like adhesive material according to any one of claims 1 to 7 and an electronic device member.

Images