Filamentous adhesive

Abstract

The present application provides an adhesive material having high adhesion and also having easy detachability. In addition, a laminate of the above-described filamentous adhesive body and an electronic device component is provided. The present application relates to a filamentous adhesive body including a core material and an adhesive covering a surface in a length direction of the core material, the adhesive containing a base polymer and bubbles.

Description

Technical Field

[0001] This invention relates to filamentous adhesives. Background Technology

[0002] In bonding applications such as electronic devices and housings, narrow adhesive materials, such as adhesive tape, are sometimes used.

[0003] For example, Patent Document 1 discloses a double-sided adhesive tape comprising an adhesive layer laminate consisting of two or more layers of adhesive layers, wherein the adhesive layers contain low-polarity fillers.

[0004] In addition, Patent Document 2 discloses an adhesive tape comprising an acrylic adhesive and a viscoelastic layer containing hollow particles or bubbles.

[0005] Existing technical documents Patent documents Patent Document 1: Japanese Patent No. 6975189 Patent Document 2: Japanese Patent No. 7024928 Summary of the Invention

[0006] The problem that the invention aims to solve In applications involving the fixing of housings / components in medium to large-sized household appliances, such as television and monitor housings, high adhesive reliability and ease of disassembly are particularly required. Regarding the adhesive tapes described in Patent Documents 1 and 2, there is room for research into improving adhesive strength, and there is also the issue of lacking ease of disassembly.

[0007] The present invention was made in view of the above-mentioned conventional realities, and aims to provide an adhesive material with high adhesive strength and easy disassembly.

[0008] Methods for solving problems In order to solve the above-mentioned problems, the inventors of this application conducted in-depth research and found that by including a base polymer and air bubbles in the adhesive in a filamentous adhesive having a core material and an adhesive covering the surface of the core material, the above-mentioned problems can be solved, thus completing the present invention.

[0009] That is, the present invention relates to the following scheme.

[0010] [1] A filamentous adhesive comprising a core material and an adhesive covering the longitudinal surface of the core material. The aforementioned adhesive contains a base polymer and bubbles.

[0011] [2] The filamentous adhesive as described in [1] further comprises particles. The tensile elastic modulus of the aforementioned particles is more than 30 times that of the aforementioned base polymer.

[0012] [3] As described in [2], the filamentous adhesive has a tensile elastic modulus of 0.01 to 3 GPa.

[0013] [4] The filamentous adhesive as described in [2] contains 10 to 60 parts by mass of the aforementioned particles relative to 100 parts by mass of the aforementioned base polymer.

[0014] [5] The filamentous adhesive as described in [1], wherein the aforementioned adhesive contains more than 0% by volume and less than 5% by volume of the aforementioned air bubbles with a diameter of 20 μm or less.

[0015] [6] The filamentous adhesive described in [1] increases its adhesive strength by heating it at a temperature between 40°C and 80°C for 1 hour.

[0016] [7] As described in [1], the filamentous adhesive is wherein the core material is multifilament yarn.

[0017] [8] The laminate is a laminate of the filamentous adhesive and electronic device components as described in any one of [1] to [7].

[0018] Invention Effects According to the present invention, an adhesive material having high adhesive strength and easy removability can be provided. Furthermore, a laminate of the aforementioned filamentous adhesive and electronic device components can be provided. Attached Figure Description

[0019] [ Figure 1 [A diagram illustrating the method for preparing samples for the splitting and peeling test.] Detailed Implementation

[0020] Hereinafter, embodiments of the filamentous adhesive of the present invention will be described in detail.

[0021] It should be noted that the present invention is not limited to the embodiments described below. Furthermore, in this specification, the use of expressions such as "~" is used to indicate the numerical values ​​or physical property values ​​preceding or following them.

[0022] [Filamentous adhesive] The filamentous adhesive according to embodiments of the present invention comprises a core material and an adhesive that covers the surface of the core material along its length, the adhesive comprising a base polymer and air bubbles.

[0023] Here, "filamentous" refers to a shape that is sufficiently long in length direction relative to width direction, and in cross-sectional shape, the ratio of the length of the major axis to the length of the minor axis (major axis / minor axis) is, for example, 200 or less, preferably 100 or less, more preferably 50 or less, further preferably 10 or less, even more preferably 5 or less, and particularly preferably 3 or less. In addition, it refers to a shape that can be bent in multiple directions and at multiple angles, like a filament.

[0024] The filamentous adhesive according to the embodiments of the present invention can bend in multiple directions and at multiple angles, and therefore can bend according to the shape of the bonding area, and can cope with the diversity of the shape of the bonding area.

[0025] The core material and adhesive constituting the filamentous adhesive according to the embodiments of the present invention will be described below.

[0026] <Core material> The filamentous adhesive according to embodiments of the present invention has a core material. By having a core material, the pull-out and removability (ease of removal) of the filamentous adhesive becomes good. The core material is preferably filamentous.

[0027] In this specification, the pull-out disassembly property of the filamentous adhesive refers to the ability to disassemble the joint by pulling out the filamentous adhesive from the joint formed by joining the adhered materials together.

[0028] The core material is preferably a multifilament yarn consisting of multiple filaments, formed by combining or twisting these filaments. When the core material is multifilament yarn, sufficient strength and stable physical properties can be obtained. As a result, a filamentous adhesive with low quality deviation, excellent strength, and excellent adhesion can be obtained. Furthermore, when it is multifilament yarn, gaps easily form between the filaments, which mitigates stress concentration in the adhesive coating the core material surface, thus dispersing stress; therefore, this is preferable.

[0029] From the viewpoint of adhesive strength, 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.

[0030] On the other hand, if the thickness (fineness) of the core material is kept at the same level, and the number of filaments increases, then each filament becomes thinner (fineness decreases). When each filament becomes too thin, it may lead to a decrease in the strength of the core material and a decrease in its processability. Therefore, the number of filaments is preferably 2,000 or less, more preferably 1,500 or less, and particularly preferably 1,000 or less.

[0031] There are no particular restrictions on the type of resin used in filaments; it can be selected appropriately based on the required strength, quality, hardness, and other properties. For example, materials including thermoplastic polymers, thermosetting polymers, and rubber can be cited.

[0032] Specifically, the following polymer materials can be used: rayon, cuprammonium cellulose, cellulose acetate, Promix, nylon, aramid, vinylon, vinylidene polymers, polyvinyl chloride, acrylonitrile fibers, polyolefins (polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, etc.), polyester resins (polyethylene terephthalate, etc.), vinyl chloride resins, vinyl acetate resins, polyimide resins, polyamide resins, fluoropolymers, polyurethane, polyvinyl chloride fiber, polylactic acid, and other polymers; synthetic rubbers (natural rubber, polyurethane, etc.); foamed polyurethane, foamed polychloroprene rubber, and other foams. Polyester resin is preferred, and polyethylene terephthalate is more preferred.

[0033] The content of filaments in the core material is preferably 10 to 100% by mass, more preferably 50 to 100% by mass, and particularly preferably 80 to 100% by mass.

[0034] The core material can be formulated with various additives as needed, such as fillers (inorganic fillers, organic fillers, etc.), anti-aging agents, antioxidants, ultraviolet absorbers, antistatic agents, lubricants, plasticizers, and colorants (pigments, dyes, etc.). Known or conventional surface treatments, such as corona discharge treatment, plasma treatment, and primer coating, can also be applied to the core material.

[0035] There are no particular restrictions on the shape of the core material; it can be adjusted appropriately according to the required strength, quality, hardness, and other properties.

[0036] The cross-sectional shape of the core material is typically circular, but in addition to circles, it can also be elliptical, polygonal, and other shapes.

[0037] The core material only needs to have multiple filaments, or it can be a combination of filaments twisted with staple yarns, processed yarns, hollow yarns, etc. As for processed yarns, examples include processed yarns that have undergone crimping, bulking, etc., and are commonly referred to as textured yarns, bulky yarns, or elastic yarns.

[0038] There is no particular limitation on the thickness of the core material; it can be adjusted appropriately according to the application to make the thickness of the filamentous adhesive suitable.

[0039] Furthermore, the twist of the core material is preferably 1 twist / m or more. When the twist is 1 twist / m or more, the impact resistance of the filamentous adhesive is improved. The twist of the core material is more preferably 20 twists / m or more, and even more preferably 50 twists / m or more.

[0040] On the other hand, in order to allow the core material to deform sufficiently when bonding multiple items, and to increase the amount of adhesive adhered per unit length, it is preferable that the twist of the core material is not too strong. Therefore, the twist of the core material is preferably 500 twists / m or less, more preferably 300 twists / m or less, and even more preferably 200 twists / m or less.

[0041] Furthermore, when twisting the core material, from the same perspective as above, it is preferable to control the twist coefficient K, as expressed by the following formula (A). The twist coefficient K is an indicator used to discuss the effects of twisting (on the core material's density, ease of deformation, amount of adhesive adhesion, etc.) regardless of the core material's thickness. That is, the effect of twisting on the core material varies depending on the core material's thickness, but if the twist coefficient K is the same, it means that the effect of twisting on the core material is the same regardless of the core material's thickness.

[0042] The twist coefficient K is preferably 0 or more, and more preferably greater than 0. On the other hand, when the twist coefficient K is 200 or less, the flexibility of the core material and, consequently, the filamentous adhesive is improved, making it easier to bond complex shapes and narrow portions such as curves, bends, and uneven parts. Therefore, the twist coefficient K is preferably 200 or less, more preferably 100 or less, and even more preferably less than 50.

[0043] [Mathematical Expression 1] In formula (A), K represents the twist coefficient, T represents the twist (twist / m), and D represents the fineness (dtex).

[0044] From the viewpoint of suppressing the reduction in strength of the filamentous adhesive, the content of the core material in the filamentous adhesive is preferably 10% by mass or more, more preferably 20% by mass or more, and particularly preferably 30% by mass or more. Furthermore, from the viewpoint of suppressing the core material from being exposed to the surface, the content of the core material in the filamentous adhesive is preferably 90% by mass or less, more preferably 80% by mass or less, and particularly preferably 70% by mass or less.

[0045] <Adhesive> The filamentous adhesive according to embodiments of the present invention has an adhesive that coats a core material, the adhesive containing a base polymer and air bubbles. The adhesive in this embodiment can be formed from an adhesive composition, and the adhesive can be an adhesive composition. Additionally, the adhesive can form a layer (adhesive layer).

[0046] The adhesive preferably covers the entire circumference of the core material's surface along its length. "Entire circumference of the core material" refers to the entire circumference of the core material, meaning the entire 360° circumference of the core material surface centered on its centerline along its length.

[0047] However, the end faces of the core material may not be covered by adhesive. For example, in cases where filamentous adhesives are cut during manufacturing or use, the end faces of the core material may not be covered by adhesive.

[0048] By covering the entire length of the core material with an adhesive, a filamentous bond with excellent strength can be obtained. This is presumably because the core material is not exposed on the surface, thus preventing stress concentration in a portion of the core material and subsequent breakage.

[0049] The coverage rate of the adhesive on the core material (the area of ​​adhesive per unit area of ​​the core material surface (%)) is preferably 50% or more, more preferably 80% or more, further preferably 90% or more, and particularly preferably 95% or more. When the coverage rate of the core material is 50% or more, it can prevent the core material from breaking and produce a filamentous adhesive with excellent strength.

[0050] The adhesive forming the adhesive layer can also be impregnated within the core material. Here, "adhesive impregnated within the core material" means that the adhesive is present between the multiple filaments within the core material. If the adhesive is impregnated within the core material, the adhesion between the adhesive and the core material is maintained, making them less prone to peeling, and the strength of the filamentous bond is increased.

[0051] (Basic polymer) The adhesive in this embodiment is formed by an adhesive based on a base polymer. The type of adhesive is not particularly limited; for example, acrylic adhesives, rubber adhesives, vinyl alkyl ether adhesives, silicone adhesives, polyester adhesives, polyamide adhesives, urethane adhesives, fluorinated adhesives, epoxy adhesives, etc., can be used.

[0052] Of the above, from the viewpoint of adhesion, acrylic adhesives and rubber adhesives are preferred, with acrylic adhesives being more preferred. It should be noted that one type of adhesive may be used alone, or two or more types may be used in combination.

[0053] Rubber-based adhesives are adhesives that use natural rubber, styrene-isoprene-styrene block copolymers, styrene-butadiene-styrene block copolymers, styrene-ethylene-butene-styrene block copolymers, styrene-butadiene rubber, polybutadiene, polyisoprene, polyisobutylene, butyl rubber, chloroprene rubber, silicone rubber, and other rubber-based polymers as the main agents.

[0054] Here, "acrylic adhesive" refers to an adhesive based on an acrylic polymer (the main component of the polymer composition, i.e., the component accounting for more than 50% by mass). "Acrylic polymer" refers to a polymer in which a monomer having at least one (meth)acryloyl group in one molecule (hereinafter, sometimes referred to as "acrylic monomer") is the main constituent monomer component (the main component of the monomer, i.e., the 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 both acryloyl and methacryloyl groups. Similarly, "(meth)acrylate" refers to both acrylates and methacrylates, and "(meth)propylene-" refers to both propylene- and methpropylene-.

[0055] As the aforementioned acrylic polymer, a preferred example is a polymer containing a monomeric raw material that includes an alkyl (meth)acrylate as the main monomer and may also include a secondary monomer that has copolymerizability with the main monomer. Here, the main monomer refers to the component in the aforementioned monomeric raw material that accounts for more than 50% by mass of the monomer composition.

[0056] As an alkyl methacrylate, for example, a compound represented by the following formula (1) may be suitably used.

[0057] CH2=C(R) 1 COOR 2 (1) Here, R in equation (1) above 1 It can be a hydrogen atom or a methyl group. Additionally, R... 2 It is a chain alkyl group having 1 to 20 carbon atoms. Hereinafter, this range of carbon atoms is sometimes expressed as "C". 1-20 ".

[0058] As R 2 C 1-20Alkyl (meth)acrylates with chain-like alkyl groups, for example, include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, sec-butyl (meth)acrylate, pentyl (meth)acrylate, isoamyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, 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)acrylate, tridecyl (meth)acrylate, tetradecyl (meth)acrylate, pentadecyl (meth)acrylate, hexadecyl (meth)acrylate, heptadecanyl (meth)acrylate, octadecyl (meth)acrylate, nonadecanyl (meth)acrylate, eicosyl (meth)acrylate, etc. These alkyl (meth)acrylates can be used alone or in combination of two or more.

[0059] From the perspective of adhesive bonding stability, etc., R 2 C 1-14 (e.g., C) 2-10 Typically, C 4-8 Alkyl (meth)acrylates with chain-like alkyl groups are suitable as the main monomers.

[0060] From the perspective of adhesive properties, R is preferred. 1 It is a hydrogen atom and R 2 C 4-8 Alkyl acrylates with chain-like alkyl groups (hereinafter, also simply referred to as C acrylates) 4-8 Alkyl esters are used as the main monomers. Preferred examples include n-butyl acrylate (BA) and 2-ethylhexyl acrylate (2EHA).

[0061] That is, preferably, the adhesive comprises an acrylic polymer, and in the aforementioned acrylic polymer, the amount of n-butyl acrylate or 2-ethylhexyl acrylate, relative to the total amount of monomer components constituting it, exceeds 50% by mass. More preferably, it is 60% by mass or more, and even more preferably 70% by mass or more. From the viewpoint of suppressing the reduction of 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.

[0062] In this embodiment, it is preferable to include more than 50% by mass of acrylic acid C relative to the total amount of monomer components constituting the acrylic polymer. 4-8When implemented as an alkyl ester, the content can be set to 60% by mass or more, 70% by mass or more, or 85% by mass or more. On the other hand, from the viewpoint of cohesion, etc., acrylic acid C... 4-8 It is appropriate to set the proportion of alkyl esters in the monomeric component to be below 99.5% by mass, or below 98% by mass (e.g., less than 97% by mass).

[0063] The total amount of (meth)acrylate alkyl esters, relative to the total amount of monomer components constituting acrylic polymers, typically exceeds 50% by mass; for example, it can be set to 70% by mass or more, 85% by mass or more, or 90% by mass or more. Conversely, the proportion of (meth)acrylate alkyl esters in the monomer components is typically less than 100% by mass. From the viewpoint of cohesion, it is usually appropriate to set it to 99.5% by mass or less, or 98% by mass or less (e.g., less than 97% by mass).

[0064] Acrylic polymers may also contain carboxyl-containing monomers as monomeric components constituting the acrylic polymer. Examples of carboxyl-containing monomers include: acrylic acid, methacrylic acid, carboxyethyl methacrylate, carboxypentyl methacrylate, crotonic acid, isocrotonic acid, and other olefinically unsaturated monocarboxylic acids; maleic acid, itaconic acid, citraconic acid, and other olefinically unsaturated dicarboxylic acids and their anhydrides (maleic anhydride, itaconic anhydride, etc.); etc. Any one of these can be used alone or in combination of two. Among these, acrylic acid (AA) and methacrylic acid (MAA) are preferred carboxyl-containing monomers. AA is particularly preferred.

[0065] In acrylic polymers copolymerized with carboxyl-containing monomers, the content of carboxyl-containing monomers relative to the total amount of monomer components constituting the acrylic polymer is not particularly limited. For example, it can be set to 0.2% by mass or more (typically 0.5% by mass or more), usually 1% by mass or more is appropriate, or it can be set to 2% by mass or more, or it can be set to 3% by mass or more.

[0066] There is no particular upper limit to the content of carboxyl monomers. From the point of view of maintaining good adhesive properties, it can be set to less than 15% by mass, less than 12% by mass, or less than 10% by mass.

[0067] Acrylic polymers can, for example, use one or more functionalized monomers as described below (excluding the carboxyl-containing monomers mentioned above) as monomeric components constituting the acrylic polymer.

[0068] Hydroxyl monomers: such as 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 3-hydroxypropyl methacrylate, 4-hydroxybutyl methacrylate, etc. (meth)acrylate hydroxyalkyl esters; unsaturated alcohols such as vinyl alcohol and allyl alcohol; polypropylene glycol mono(meth)acrylate.

[0069] Amide-containing monomers: such as (meth)acrylamide, N,N-dimethyl (meth)acrylamide, N-butyl (meth)acrylamide, N-hydroxymethyl (meth)acrylamide, N-hydroxymethylpropane (meth)acrylamide, N-methoxymethyl (meth)acrylamide, N-butoxymethyl (meth)acrylamide.

[0070] Amino-containing monomers: such as aminoethyl methacrylate, N,N-dimethylaminoethyl methacrylate, and tert-butylaminoethyl methacrylate.

[0071] Monomers with epoxy groups: for example, glycidyl (meth)acrylate, methyl glycidyl (meth)acrylate, and allyl glycidyl ether.

[0072] Cyano-containing monomers: such as acrylonitrile and methacrylonitrile.

[0073] Ketone-containing monomers: such as diacetone (meth)acrylamide, diacetone (meth)acrylate, vinyl methyl ketone, vinyl ethyl ketone, allyl acetoacetate, vinyl acetoacetate.

[0074] Monomers having a ring containing a nitrogen atom: for example, N-vinyl-2-pyrrolidone, N-methylvinylpyrrolidone, N-vinylpyridine, N-vinylpiperidone, N-vinylpyrimidine, N-vinylpiperazine, N-vinylpyrazine, N-vinylpyrrole, N-vinylimidazolium, N-vinyloxazole, N-vinylmorpholine, N-vinylcaprolactam, N-(meth)acryloylmorpholine.

[0075] When the monomer component constituting the acrylic polymer includes functionalized monomers as described above, the content of the functionalized monomers in the monomer component is not particularly limited. From the viewpoint of appropriately maximizing the effects of using functionalized monomers, the content of functionalized monomers in the monomer component can be, for example, set to 0.1% by mass or more, typically 0.5% by mass or more, or even 1% by mass or more. Furthermore, from the viewpoint of easily obtaining a balanced adhesive performance, it is generally appropriate to set it to 40% by mass or less, preferably 20% by mass or less, or even 10% by mass or less (e.g., 5% by mass or less). The technology disclosed herein can also preferably be implemented in a manner where the monomer component substantially does not contain functionalized monomers (e.g., the monomer component substantially contains only (meth)acrylate and carboxyl-containing monomers). Here, "the monomer component substantially does not contain functionalized monomers" means at least unintentionally using functionalized monomers, for example, unintentionally containing 0.05% by mass or less (typically 0.01% by mass or less) of functionalized monomers is permissible.

[0076] The monomer components constituting acrylic polymers may include other copolymer components besides the monomers mentioned above. Examples of other copolymer components include vinyl ester monomers such as vinyl acetate, vinyl propionate, and vinyl laurate; aromatic vinyl compounds such as styrene, substituted styrene (α-methylstyrene, etc.), and vinyltoluene; cycloalkyl methacrylates such as cyclohexyl methacrylate, cyclopentyl methacrylate, and isobornyl methacrylate; and aromatic aryl methacrylates (e.g., phenyl methacrylate), aryloxyalkyl methacrylates (e.g., phenoxyethyl methacrylate), and arylalkyl methacrylates (e.g., benzyl methacrylate). Cyclic (meth)acrylates; olefin monomers such as ethylene, propylene, isoprene, butadiene, and isobutylene; chlorine-containing monomers such as vinyl chloride and vinylidene chloride; isocyanate-containing monomers such as 2-(meth)acryloyloxyethyl isocyanate; alkoxy-containing monomers such as (meth)acrylate methoxyethyl ethyl ethyl ethyl ethyl ethyl ethyl acrylate; vinyl ether 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) in one molecule, such as 1,6-hexanediol di(meth)acrylate and trimethylolpropane tri(meth)acrylate; etc.

[0077] The amount of the other copolymer component can be appropriately selected according to the purpose and use, and there is no particular limitation. From the viewpoint of properly exerting the effect brought about by its use, it is generally appropriate to set it to 0.05% by mass or more, and it can also be set to 0.5% by mass or more. In addition, from the viewpoint of easily obtaining a balanced adhesive performance, it is generally appropriate to set the content of the other copolymer component in the monomer component to 20% by mass or less, and it can also be set to 10% by mass or less (e.g., 5% by mass or less). In this embodiment, it is also preferable to implement it in a manner in which the monomer component does not substantially contain other copolymer components. Here, "the monomer component does not substantially contain other copolymer components" means that, at least unintentionally, other copolymer components can be used, and unintentionally containing, for example, 0.01% by mass or less of other copolymer components is permissible.

[0078] The tensile modulus of elasticity (E) of the basic polymer p The tensile modulus of elasticity (E) of the base polymer is preferably 0.1 MPa or higher, more preferably 0.2 MPa or higher, and even more preferably 0.25 MPa or higher. Additionally, the tensile modulus of elasticity (E) of the base polymer... p Preferably, the pressure is 3 MPa or less, more preferably 2.5 MPa or less, and even more preferably 2 MPa or less.

[0079] The tensile modulus of elasticity (E) of the basic polymer p For example, it can be calculated as follows. First, the storage modulus (G) of the base polymer is determined by using dynamic viscoelasticity measurement with a viscoelastic testing machine. p Using equation (1) as shown below, the tensile modulus of elasticity (E) of the base polymer is calculated. p ).

[0080] G 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.

[0081] More specifically, the method described in the embodiments described later can be used for determination.

[0082] In embodiments of the present invention, the base polymer can be obtained by (co)polymerizing monomer components. The polymerization method is not particularly limited, and examples include solution polymerization, emulsion polymerization, bulk polymerization, suspension polymerization, and photopolymerization (active energy radiation polymerization). When the base polymer is copolymerized, it can be any of the following: random copolymer, block copolymer, alternating copolymer, graft copolymer, etc.

[0083] As an emulsion polymerization method, it can be obtained by using an emulsifier and a polymerization initiator to emulsion polymerize the aforementioned raw material monomers (monomer mixture).

[0084] As the aforementioned emulsifier, a reactive emulsifier having polymerizable groups (hereinafter referred to as "reactive emulsifier"; sometimes also called "reactive surfactant") can also be used. By using a reactive emulsifier, the emulsifier is incorporated into the base polymer, reducing contamination from the emulsifier, and is therefore preferred.

[0085] Examples of reactive emulsifiers include those obtained by introducing free radical polymerizable functional groups such as vinyl, propylene, isopropylene, vinyl ether, and allyl ether groups into anionic, nonionic, and cationic emulsifiers. Specifically, examples include ammonium polyoxyethylene styrene-propylene phenyl ether sulfate, ammonium polyoxyethylene-1-(allyloxymethyl)alkyl ether sulfate, polyoxyethylene styrene-propylene phenyl ether, polyoxyethylene-1-(allyloxymethyl)alkyl ether, and ammonium-α-sulfonyl-ω-1-(allyloxymethyl)alkyloxypolyoxyethylene. When a reactive emulsifier is used, the base polymer obtained by emulsion polymerization contains monomer units derived from the reactive emulsifier.

[0086] As reactive emulsifiers, commercially available products under trade names such as "ADEKA REASOAP SE-10N" (manufactured by ADEKA Co., Ltd.), "AQUALON HS-10" (manufactured by Daiichi Kogyo Pharmaceutical Co., Ltd.), "AQUALON HS-05" (manufactured by Daiichi Kogyo Pharmaceutical Co., Ltd.), "AQUALON HS-1025" (manufactured by Daiichi Kogyo Pharmaceutical Co., Ltd.), "AQUALONKH-1025" (manufactured by Daiichi Kogyo Pharmaceutical Co., Ltd.), and "AQUALON AR-10" (manufactured by Daiichi Kogyo Pharmaceutical Co., Ltd.) may also be used.

[0087] The amount of the aforementioned reactive emulsifier used is preferably 0.1 to 10 parts by mass relative to 100 parts by mass of the total amount of raw material monomers constituting the base polymer (all raw material monomers), more preferably 0.5 to 6 parts by mass, and even more preferably 1 to 4 parts by mass.

[0088] There are no particular limitations on the aforementioned polymerization initiators; azo polymerization initiators, peroxide polymerization initiators, redox polymerization initiators, and other polymerization initiators commonly used in emulsion polymerization can be used.

[0089] Furthermore, the base polymer is preferably a polymer obtained by polymerization using a chain transfer agent. For example, terpene compounds such as α-pinene, β-pinene, limonene, and terpinene are preferred as chain transfer agents. Compounds having thiol or hydroxyl groups are also generally known.

[0090] Examples of compounds containing a thiol group include, for example, thiols such as lauryl thiol, 2-mercaptoethanol, tert-dodecyl thiol, and mercaptosuccinic acid; alkyl esters of mercaptopropionic acid such as n-butyl mercaptopropionate and octyl mercaptopropionate; and alkoxyalkyl esters of mercaptopropionic acid such as methoxybutyl mercaptopropionate. Examples of compounds containing a hydroxyl group include, for example, alcohols such as methanol, n-propanol, isopropanol (IPA), tert-butanol, and benzyl alcohol.

[0091] The amount of the aforementioned chain transfer agent is preferably 0 to 1 part by mass relative to the total amount of raw material monomers used in emulsion polymerization (all raw material monomers) of 100 parts by mass. By setting it to less than 1 part by mass, it is possible to prevent the decrease in water resistance, heat resistance, etc. caused by the reduction in molecular weight, and to prevent the problem of guide roller contamination, so it is preferred.

[0092] Emulsion polymerization of a basic polymer can be performed by emulsifying the monomer components in an aqueous medium using conventional methods, followed by emulsion polymerization. This allows the preparation of an aqueous dispersion (polymer emulsion) containing the basic polymer.

[0093] (bubble) The adhesive in this embodiment contains air bubbles. In this specification, air bubbles in the adhesive refer to tiny voids present in the adhesive.

[0094] The reason for the excellent adhesive strength of the filamentous adhesive in this embodiment is still uncertain. It is speculated that by including air bubbles in the adhesive, the adhesive around the air bubbles is easily deformed when stress is applied to the filamentous adhesive, the stress is dispersed, and the adhesive strength is improved.

[0095] More specifically, when a force is applied to peel a filamentous adhesive bonded to an adherend, stress concentrates at specific points in the adhesive. If tiny air bubbles are present at these stress concentration points, the adhesive is prone to deformation in the tensile direction. It is hypothesized that this stretching of the adhesive disperses the stress, resulting in high adhesive strength.

[0096] As for the size of the bubble, for example, the diameter can be less than 20 μm, less than 15 μm, or less than 10 μm. Additionally, as a lower limit, for example, it can be greater than 0.5 μm, greater than 1 μm, or greater than 5 μm.

[0097] The content of air bubbles with a diameter of 20 μm or less in the adhesive is preferably more than 0% by volume, more preferably 0.5% by volume or more, even more preferably 1.0% by volume or more, particularly preferably 1.5% by volume or more, and most preferably 2.0% by volume or more. As long as the adhesive contains a trace amount of air bubbles, the effect of improving the adhesive strength of the filamentous adhesive can be easily obtained. Furthermore, the air bubble content is preferably 10% by volume or less, more preferably 5% by volume or less. By keeping the air bubble content at 10% by volume or less, it is easy to suppress the reduction in the bulk strength of the adhesive.

[0098] As for the content of bubbles, it is preferable that the adhesive contains more than 0% by volume and less than 10% by volume, more preferably more than 0% by volume and less than 5% by volume, and even more preferably more than 2% by volume and less than 5% by volume, with a diameter of 20 μm or less.

[0099] The size and content of air bubbles in the adhesive can be determined, for example, by observational images obtained using a scanning electron microscope or an X-ray CT scanner. More specifically, they can be determined using the methods described in the examples below.

[0100] Air bubbles are preferably not present on the surface of the adhesive (the surface of the filamentous adhesive), but rather within the adhesive, particularly near the core material. By allowing air bubbles to exist within the adhesive rather than on the surface, it is possible to suppress the reduction of adhesive strength.

[0101] There are no particular limitations on the means by which air bubbles are incorporated into the adhesive. For example, in manufacturing the filamentous adhesive according to this embodiment, air bubbles can be incorporated into the adhesive by performing the following step: coating a coating liquid containing the aforementioned base polymer and the particles described later onto a core material and drying it, thereby forming an adhesive on the surface of the core material. Furthermore, it is possible to contain air bubbles near the core material rather than on the surface of the adhesive. This is presumably because, during the drying process of the coating liquid, as the solvent or dispersion medium contained in the coating liquid evaporates and causes drying shrinkage, tiny voids are easily generated due to the difference in shrinkage rates between the base polymer and the particles.

[0102] (particle) The adhesive in this embodiment also contains particles, preferably with a tensile modulus of elasticity that is more than 30 times that of the base polymer. It is speculated that by including particles in the adhesive with a relatively high tensile modulus of elasticity compared to the base polymer, stress dispersion when stress is applied to the filamentous adhesive is further promoted, thereby further improving the adhesive strength.

[0103] In addition, as described above, by coating the core material with a coating liquid containing the base polymer and the particles and drying it to form an adhesive on the surface of the core material, it is possible to contain air bubbles in the adhesive.

[0104] The above-mentioned particles can be used in single or multiple ways.

[0105] The tensile modulus of elasticity of particles (E) f The preferred tensile modulus of elasticity (E) of the base polymer is... p The strength of the adhesive is 30 times or more, preferably 100 times or more, more preferably 300 times or more, and can be 500 times or more, 800 times or more, or 1000 times or more. As an upper limit, from the viewpoint of improving the dispersibility of particles in the adhesive, it can be set to 1500 times or less, for example.

[0106] The tensile modulus of elasticity of particles (E) f The tensile modulus of elasticity (E) of the particles is preferably 0.01 GPa or higher, more preferably 0.05 GPa or higher, and even more preferably 0.10 GPa or higher. Additionally, the tensile modulus of elasticity of the particles (E) is... f Preferably, the pressure is 3 GPa or less, more preferably 2 GPa or less, and even more preferably 1 GPa or less.

[0107] The tensile modulus of elasticity of particles (E) f The preferred pressure is 0.01–3 GPa.

[0108] The tensile modulus of elasticity of particles (E) f For example, a nanoindenter can be used to measure it. More specifically, the methods described in the examples below can be used to measure it.

[0109] The average particle size is preferably 0.05 μm or more, more preferably 0.075 μm or more, and even more preferably 0.1 μm or more. As an upper limit for the average particle size, from the viewpoint of manufacturability and appearance of the filamentous adhesive, it 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 is preferably 0.05 μm to 35 μm. It should be noted that the above-mentioned average particle size is the median particle size (D50) measured using dynamic light scattering. In embodiments of the present invention, when the adhesive contains two or more types of particles, the above-mentioned average particle size is the average particle size of all particles.

[0110] The aforementioned particles can be any of organic or inorganic substances. Examples of materials constituting the aforementioned inorganic substances include, for instance, metals such as copper, silver, gold, platinum, nickel, aluminum, chromium, iron, and stainless steel; metal oxides such as alumina, silicon dioxide, titanium dioxide, zirconium oxide, zinc oxide, tin oxide, copper oxide, and nickel oxide; metal hydroxides and hydrated metal compounds such as 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, hydrotalcite, sodium aluminum carbonate, borax, and zinc borate; carbides such as silicon carbide, boron carbide, nitrogen carbide, and calcium carbide; nitrides such as aluminum nitride, silicon nitride, boron nitride, and gallium nitride; carbonates such as calcium carbonate; titanates such as barium titanate and potassium titanate; carbon-based substances such as carbon black, carbon nanotubes, carbon fibers, and diamond; inorganic materials such as glass; and natural raw material particles such as volcanic ash sand, clay, and sand.

[0111] Examples of materials constituting the aforementioned organic compounds include, for example, polystyrene, acrylic resins (e.g., polymethyl methacrylate), phenolic resins, benzoguanamine resins, urea resins, silicone resins, polyesters, polyurethanes, polyethylene, polypropylene, polyamides (e.g., nylon), polyimide, polyvinylidene chloride, and other polymers. Rubber-based resins such as natural rubber and synthetic rubber may also be used.

[0112] The particles described above are preferably composed of organic matter, more preferably of polyethylene, polyamide, acrylonitrile butadiene rubber, acrylic resin, styrene butadiene rubber, or polystyrene, and even more preferably of polyethylene or polyamide.

[0113] In the adhesive of the embodiments 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, relative to 100 parts by mass of the base polymer. By setting it to 10 parts by mass or more, it is easy to obtain the effect of improved adhesive strength due to improved stress dispersion. In addition, relative to 100 parts by mass of the base polymer, it 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. By setting it to 60 parts by mass or less, it is easy to suppress the decrease in adhesive strength.

[0114] In the adhesive of the embodiments of the present invention, it is preferable to include 10 to 60 parts by mass of the above-mentioned particles relative to 100 parts by mass of the base polymer.

[0115] In addition to basic polymers, bubbles, and particles, adhesives may also contain appropriate amounts of tackifying resins, crosslinking agents, viscosity modifiers (thickening agents, etc.), leveling agents, peel modifiers, plasticizers, softeners, fillers, colorants (pigments, dyes, etc.), surfactants, antistatic agents, preservatives, anti-aging agents, ultraviolet absorbers, antioxidants, light stabilizers, and other additives.

[0116] It is preferable to incorporate a crosslinking agent into the acrylic adhesive. Commonly used crosslinking agents can be used as the crosslinking agent in the acrylic adhesive, such as silane-based crosslinking agents, organic peroxides, epoxy compounds, amino-containing compounds, organometallic salts, metal alkoxides, metal chelates, hydrazide-based crosslinking agents, carbodiimide-based crosslinking agents, isocyanate-based crosslinking agents, and silanol-based crosslinking agents. From the perspective of rapidly completing crosslinking after the adhesive composition dries, organometallic salts, metal chelates, hydrazide-based crosslinking agents, and silane-based crosslinking agents are preferred. In the case of water-dispersible adhesives, hydrazide-based crosslinking agents and silane-based crosslinking agents are particularly preferred. The crosslinking agent can be either oil-soluble or water-soluble, and can be used alone or in combination of two or more.

[0117] As a silane-based crosslinking agent, a silane monomer capable of copolymerizing with the aforementioned alkyl (meth)acrylate is preferred. There are no particular limitations on the silane monomer, as long as it is a polymerizable compound having silicon atoms; however, from the perspective of excellent copolymerization with the aforementioned alkyl (meth)acrylate, silane compounds having (meth)acryloyl groups, such as (meth)acryloyloxyalkylsilane derivatives, are preferred. Examples of silane monomers include, for example, γ-methacryloyloxypropyltrimethoxysilane, 3-acryloyloxypropyltrimethoxysilane, 3-methacryloyloxypropyltriethoxysilane, 3-acryloyloxypropylmethyldimethoxysilane, 3-acryloyloxypropylmethyldimethoxysilane, 3-methacryloyloxypropylmethyldiethoxysilane, and 3-acryloyloxypropylmethyldiethoxysilane. These silane monomers can be used alone or in combination of two or more.

[0118] In addition to the above, other silane monomers capable of copolymerization include, for example, vinyltrimethoxysilane, vinyltriethoxysilane, 4-vinylbutyltrimethoxysilane, 4-vinylbutyltriethoxysilane, 8-vinyloctyltrimethoxysilane, 8-vinyloctyltriethoxysilane, 10-methacryloyloxydecyltrimethoxysilane, 10-acryloyloxydecyltrimethoxysilane, 10-methacryloyloxydecyltriethoxysilane, 10-acryloyloxydecyltriethoxysilane, etc.

[0119] The amount of crosslinking agent used can be appropriately selected according to the type of monomer raw material and the intended use of the adhesive article. In this embodiment, the amount of crosslinking agent relative to 100 parts by weight of the aforementioned monomer raw material (excluding crosslinking agent) is preferably 0.005 to 5 parts by weight, and more preferably in the range of 0.01 to 3 parts by weight.

[0120] In this embodiment, other crosslinking agents may also be used, such as crosslinking with other crosslinking agents, UV crosslinking, electron beam crosslinking, and other radiation crosslinking. As the aforementioned other crosslinking agents, commonly used crosslinking agents can be used, for example, organic peroxides, epoxy compounds, amino-containing compounds, organometallic salts, metal alkoxides, metal chelates, hydrazide-based crosslinking agents, carbodiimide-based crosslinking agents, isocyanate-based crosslinking agents, silane or silanol-based crosslinking agents, etc. Other crosslinking agents can be either oil-soluble or water-soluble.

[0121] Any suitable tackifying resin can be used. Specific examples of tackifying resins 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 resins, xylene resins, etc.), aliphatic-aromatic petroleum resins, aliphatic-alicyclic petroleum resins, hydrogenated hydrocarbon resins, coumarone resins, coumarone-indene resins, etc.), phenolic tackifying resins (e.g., alkylphenolic resins, xylene-formaldehyde resins, Resol, Novolac, etc.), ketone-based tackifying resins, polyamide-based tackifying resins, epoxy-based tackifying resins, and elastic system tackifying resins, etc. The preferred adhesives are rosin-based, terpene-based, or hydrocarbon-based (styrene-based, etc.) adhesives. Two or more adhesives can be used alone or in combination.

[0122] In the case where the adhesive includes a tackifying resin, the amount of the tackifying resin added is preferably 1 part by weight or more, more preferably 10 parts by weight or more, further preferably 20 parts by weight or more, and even more preferably 30 parts by weight or more, relative to 100 parts by weight of the base polymer. Furthermore, from the viewpoint of suppressing a decrease in the adhesive strength of the adhesive, it is preferably 100 parts by weight or less, more preferably 90 parts by weight or less, and even more preferably 70 parts by weight or less.

[0123] Regarding the adhesive composition that forms the adhesive, it is preferable to include a base polymer and a tackifying resin, and to include 1 to 100 parts by weight of the tackifying resin relative to 100 parts by weight of the base polymer. More preferably, it includes a base polymer, particles, and a tackifying resin, and to include 10 to 60 parts by weight of the particles and 1 to 100 parts by weight of the tackifying resin relative to 100 parts by weight of the base polymer.

[0124] Here, the adhesive composition forming the adhesive may contain air bubbles, but the adhesive composition may also not contain air bubbles as long as the formed adhesive contains air bubbles.

[0125] It should be noted that either solvent-based or water-dispersible adhesives can be used as the adhesive composition. From the perspectives of high-speed coating capability, environmental friendliness, and minimal impact of the solvent on the core material (swelling, dissolution), a water-dispersible adhesive composition is preferred.

[0126] Specifically, the amount of adhesive adhered (the 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 amount of adhesive adhered is excessive, the adhesive composition needs to be applied to the core material multiple times during the manufacturing process, or the drying time of the applied adhesive composition is long, resulting in low manufacturing efficiency. Therefore, the amount of adhesive adhered is preferably 200 mg / m or less, more preferably 180 mg / m or less, and even more preferably 160 mg / m or less.

[0127] From the viewpoint of increasing the coverage of the core material, the adhesive content in the filamentous adhesive is preferably 10% by mass or more, more preferably 20% by mass or more, and particularly preferably 30% by mass or more. Furthermore, from the viewpoint of suppressing the reduction in strength of the filamentous adhesive, the adhesive content in the filamentous adhesive is preferably 90% by mass or less, more preferably 80% by mass or less, and particularly preferably 70% by mass or less.

[0128] In this embodiment, from the viewpoint of strength and operability, the filament width of the filamentous adhesive is preferably 50 to 2000 μm, more preferably 100 to 1000 μm.

[0129] In this embodiment, the adhesive strength of the filamentous adhesive is preferably increased by heating it at a temperature of 40°C to 80°C for 1 hour.

[0130] From the viewpoint of improving the adhesion 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.

[0131] When using filamentous adhesives whose adhesive strength increases with heat aging to fix the adhered materials together, for example, by heat aging after they are bonded together, the adhesive strength can be further improved.

[0132] In order to form a filamentous adhesive whose adhesive strength is improved by heat aging, for example, an adhesive containing the above-mentioned particles can be formed, and the type and content of the particles are set within the preferred ranges described above.

[0133] There are no particular limitations on the heating method. For example, the filamentous adhesive can be placed in a dryer set to a heating temperature while it is bonded to the substrate, and then aged.

[0134] It should be noted that although the detailed mechanism by which heat aging increases the adhesive strength of filamentous adhesives is still uncertain, it is speculated that the reason is that heat aging increases the number of air bubbles in the adhesive, thereby increasing the stress transmission path in the adhesive.

[0135] [Method for manufacturing filamentous adhesives] The filamentous adhesives according to embodiments of the present invention can be manufactured by known methods, for example, by methods including a coating process (coating a coating liquid that forms an adhesive onto a core material).

[0136] The coating solution is applied to the core material by means of dipping, impregnation, coating, etc., and then heated and dried as needed.

[0137] Heating and drying can be carried out, for example, at 80–120°C, preferably 90–110°C, for example, for 20 seconds to 3 minutes, preferably 30 seconds to 2 minutes.

[0138] The coating liquid can be applied using conventional coating machines such as gravure roller coaters, reverse roller coaters, roller kiss coaters, roller dip coaters, bar coaters, doctor blade coaters, and spray coaters.

[0139] As long as the formed adhesive contains air bubbles, the above-mentioned coating liquid may be bubble-free. For example, an adhesive containing air bubbles can be formed by using a coating liquid containing the above-mentioned base polymer and particles that is bubble-free, applying the coating liquid to the core material and drying it.

[0140] The manufacturing method of the filamentous adhesive according to the embodiments of the present invention preferably includes a coating step of coating a coating liquid containing the above-mentioned base polymer and particles onto the above-mentioned core material, and a drying step of drying the coated coating liquid.

[0141] The method for manufacturing the filamentous adhesive of this embodiment may or may not include a fiber-opening step. In the fiber-opening step, when the adhesive is applied to the core material, the core material is opened by moving it along a non-rotating roller.

[0142] Furthermore, when the method for manufacturing the filamentous adhesive of this embodiment includes a coating step, a roller is preferably used in the coating step, and the rotational speed of the roller is 0.3 to 5.0 times the core material extraction speed. By keeping the roller rotational speed within the above range, core material fiber opening can be suppressed.

[0143] The rotational speed of the roller is more preferably 0.4 to 4.0 times the core material extraction speed, more preferably 0.5 to 3.0 times, and particularly preferably 0.8 to 1.5 times.

[0144] Furthermore, during the coating process, it is preferable to apply a tension of 6.0 mN / dtex or less to the core material. By applying a tension of 6.0 mN / dtex or less to the core material, fiber breakage can be suppressed.

[0145] 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.

[0146] Applications of filamentous adhesives Furthermore, the filamentous adhesive according to embodiments of the present invention can be applied to narrow components and areas with limited width while suppressing exposure. It is also easy to apply to complex shapes such as curves, curved surfaces, and uneven surfaces. In addition, it is preferred that it can be easily disassembled (reprocessed). Furthermore, due to its excellent adhesive strength, it can be used for bonding various articles.

[0147] For example, the filamentous adhesive according to the embodiments of the present invention can be suitably used for fixing articles in the manufacture of electronic devices and for fixing vehicle components. In particular, it can be applied to fixing housings / components of medium and large household appliances, such as television and monitor housings.

[0148] Furthermore, when applying adhesive tape to objects with complex shapes such as curves, surfaces, or unevenness, the tape may wrinkle or overlap, making it difficult to prevent exposure and achieve an aesthetically pleasing finish. Furthermore, wrinkles and overlaps can be a major cause of reduced adhesion. While cutting the tape into thinner pieces can be considered to avoid wrinkles and overlaps, this significantly worsens operability. On the other hand, the filamentous adhesive according to the embodiments of this invention can firmly adhere even to complex shapes such as curves, surfaces, or unevenness without wrinkles or overlaps. Moreover, this filamentous adhesive can be applied to the desired area in a single, one-step process, resulting in excellent operability and applicability to automated production lines.

[0149] Specifically, the filamentous adhesives described in the embodiments of the present invention can be suitably used, for example, to fix various wires (wire-like components) such as cables such as wires and optical fibers, fiber optic lights, fiber optic sensors such as FBG (Fiber Bragg Gratings), filaments, ropes, and threads, and narrow components in a desired form.

[0150] If the filamentous adhesive according to the embodiments of the present invention is used, even when fixing wires or narrow components to other components in complex shapes, it is possible to securely fix them with excellent operability while suppressing exposure, wrinkles, and overlap, according to the complex shape that the wires or narrow components should have. It should be noted that when fixing wires or narrow components to other components, the filamentous adhesive according to the embodiments of the present invention can be pre-attached according to the desired fixing shape of the wires or narrow components on the surface of the other components, and then the wires or narrow components can be attached and fixed by aligning the filamentous adhesive attached to the surface of the other components. Alternatively, the wires or narrow components can be fixed to other components in the desired shape after attaching the filamentous adhesive according to the embodiments of the present invention to the wires or narrow components.

[0151] Furthermore, the filamentous adhesive according to embodiments of the present invention can also be suitably used for the temporary fixation (temporary fastening) of articles by temporarily securing (temporarily fastening) one article to the surface of another article. More specifically, the filamentous adhesive according to embodiments of the present invention can be used, for example, for the temporary fixation (temporary fastening) of textile products such as clothing, shoes, bags, and hats, and leather products. However, its uses are not limited to this, and it can be suitably used for various applications where temporary fixation (temporary fastening) is desired.

[0152] For example, when fixing one item to the surface of another item, the first item is temporarily fixed to the surface of the second item using a filamentous adhesive for positioning, and then the two items are fixed (formally fixed) using methods such as heat pressing or sewing. In this case, if the filamentous adhesive according to the embodiments of the present invention is used, it is easy to avoid the fixing part provided between the two items for temporary fixing. For example, when sewing fiber products or leather products, if a filamentous adhesive is used for temporary fixing, it is easy to avoid the sewing part for temporary fixing, and it is easy to prevent the adhesive from adhering to the needle.

[0153] Furthermore, if it is a filamentous adhesive according to the embodiments of the present invention, as described above, even if the two items have complex shapes such as curves, curved surfaces, or concave and convex shapes, they can be well bonded while suppressing exposure, wrinkles, and overlap, and can be bonded in one step, with good operability.

[0154] Furthermore, for example, even easily deformable components such as raw materials, fabrics, and leathers that constitute fiber or leather products can be temporarily fixed using the filamentous adhesives described in the embodiments of the present invention, thereby suppressing or preventing deformation of the components caused by stretching, and improving the design after fixing (formal fixing).

[0155] Furthermore, if it is a filamentous adhesive as described in the embodiments of the present invention, it is easy to remove the filamentous adhesive as described in the embodiments of the present invention from between the two fixed (formally fixed) articles as needed after the two articles are fixed (formally fixed). In this way, it is possible to prevent the adhesive from being exposed and to effectively prevent design deterioration caused by discoloration of residual adhesive over time.

[0156] Furthermore, when applying adhesives to the objects to be bonded (adhesives), the filamentous adhesive according to embodiments of the present invention can be used as a barrier material to prevent the adhesive from spilling out. For example, the barrier material can be used to prevent the spillage of sealing resin used in the bonding of optical panels. When the filamentous adhesive is used as a barrier material, it can be peeled off or left in place after the adhesive has cured.

[0157] In addition, if it is a filamentous adhesive according to the embodiments of the present invention, it can also be made into composite filaments by twisting it with filaments formed from other materials, or by weaving it with filaments or cloths (including non-woven fabrics and sheets) formed from other materials, thereby achieving functional integration.

[0158] [Layered Body] The present invention also relates to the above-mentioned filamentous adhesive and laminate of electronic device components.

[0159] As electronic device components, examples include narrow bezels of mobile terminals such as mobile phones and smartphones, laptops, headphones, headsets, speakers, thin displays, game consoles, digital cameras, electronic dictionaries, wires, optical fibers and other cables, LED fiber optic lights, and fiber optic sensors such as FBG.

[0160] The laminated body involved in the embodiments of the present invention can be a joint body formed by joining multiple electronic device components with filamentous adhesive.

[0161] As explained above, the following matters are disclosed in this specification.

[0162] <1> A filamentous adhesive comprising a core material and an adhesive covering the longitudinal surface of the core material. The aforementioned adhesive contains a base polymer and bubbles.

[0163] <2> The filamentous adhesive as described in <1> further comprises particles. The tensile elastic modulus of the aforementioned particles is more than 30 times that of the aforementioned base polymer.

[0164] <3> As described in <2>, the filamentous adhesive, wherein... The tensile elastic modulus of the aforementioned particles is 0.01–3 GPa.

[0165] <4> The filamentous adhesive as described in <2> contains 10 to 60 parts by mass of the aforementioned particles relative to 100 parts by mass of the aforementioned base polymer.

[0166] <5> The filamentous adhesive as described in any one of <1> to <4>, wherein the aforementioned adhesive contains more than 0% by volume and less than 5% by volume of the aforementioned air bubbles with a diameter of 20 μm or less.

[0167] <6> The filamentous adhesive as described in any one of <1> to <5> increases its adhesive strength by heating it at 40°C to 80°C for 1 hour.

[0168] <7> As described in <1>, the filamentous adhesive body, wherein the aforementioned core material is multifilament yarn.

[0169] <8> A laminate, which is a laminate of a filamentous adhesive and an electronic device component as described in any one of <1> to <7>.

[0170] Example The present invention will be described in more detail below with examples, but the present invention is not limited to the following examples.

[0171] <Preparation of Acrylic Polymer Emulsions> (Preparation of acrylic polymer emulsion 1) To a reaction vessel equipped with a thermometer, stirrer, nitrogen inlet tube, and reflux condenser, add 0.07 parts by weight of reactive surfactant (AQUALON KH-1025 / manufactured by Daiichi Kogyo Pharmaceutical Co., Ltd.) and 61.1 parts by weight of distilled water, and perform nitrogen replacement at 60°C for 1 hour while stirring. Then, add 0.10 parts by weight of polymerization initiator (VA-057 / manufactured by Fujifilm and Kazumitsu Chemical Co., Ltd.). While slowly adding dropwise a substance prepared by emulsifying 28 parts by mass of distilled water with 85 parts by mass of 2-ethylhexyl acrylate (2EHA), 13 parts by mass of methyl acrylate (MA), 1.25 parts by mass of acrylic acid (AA), 0.75 parts by mass of methacrylic acid (MAA), 0.025 parts by mass of tert-dodecyl mercaptan (chain transfer agent), 0.02 parts by mass of 3-methacryloyloxypropyltrimethoxysilane (KBM-503), and 1.93 parts by mass of the above-mentioned reactive surfactant, emulsion polymerization was carried out at 60°C for 4 hours. Then, the mixture was maintained at 60°C for 3 hours, followed by the addition of 0.05 parts by mass of the above-mentioned polymerization initiator, and then maintained at 60°C for 2 hours. The system was cooled to room temperature, and the pH was adjusted to 7 using 10% ammonia water as a pH adjuster. 0.0072 parts by mass of a preservative (Neosintol 2208 / Sumika Enviro-Science Co., Ltd.) was added. An aqueous dispersion of an acrylic polymer (acrylic polymer emulsion 1) was thus prepared. The solid component concentration of this acrylic polymer was 50.5% by mass, and the sol weight-average molecular weight (Mw) was 340,000.

[0172] <Preparation of Adhesive Compositions> (Preparation of adhesive composition 1) Acrylic polymer emulsion 1 contains 100 parts by weight of acrylic polymer, with tackifying resin emulsion (manufactured by Arakawa Chemical Industry Co., Ltd., trade name "TAMANOLE200NT") added to a weight of 35 parts by weight. Then, relative to 100 parts by weight of acrylic polymer, 0.07 parts by weight of silane coupling agent (manufactured by Shin-Etsu Chemical Co., Ltd., trade name "Z-6210") is added. After diluting the solid component concentration to 45% by weight with deionized water, 10% by weight of ammonia water as a pH adjuster and polyacrylic acid (manufactured by Toa Synthetic Co., Ltd., trade name "ARON A-10H") as a tackifier are used to adjust the pH and viscosity to a suitable level for coating, resulting in adhesive liquid 1. The amount of ammonia water added relative to 100 parts by weight of acrylic polymer is 1.5 parts by weight, and the amount of polyacrylic acid added is 4 parts by weight.

[0173] Polyamide particles (manufactured by Sumitomo Seika Co., Ltd., trade name "SEPOLSION PA200") and distilled water were added to the adhesive liquid 1 in such a way that the particles were 10 parts by mass relative to 100 parts by mass of acrylic polymer. The mixture was stirred at 1000 rpm for 5 minutes using a high-speed disperser and the air bubbles were removed using a centrifugal degassing machine, thereby obtaining an adhesive composition 1 with a solid component concentration of 34% by mass.

[0174] (Preparation of adhesive compositions 2-6) Except for changing the type and amount of added particles as described in Table 1, adhesive compositions 2 to 6 are obtained by operating in the same manner as adhesive composition 1.

[0175] <Manufacturing of Filament Adhesives> (Example 1) As the core material, a multifilament yarn (core material 1) was prepared by twisting 7 polyethylene terephthalate (PET) fibers (manufactured by TEIJIN FRONTIER CO., LTD.) with a fineness of 167 dtex and a filament number of 48 with an application of 150 twists per meter.

[0176] For the aforementioned core material, adhesive composition 1 was applied by dip coating using a coating roller. Then, it was dried at 80°C for 5 minutes to obtain a filamentous adhesive with a paste weight (adhesive amount) of 50 mg / m.

[0177] (Examples 2-7, Comparative Example 1) Except for changing the type of adhesive composition as described in Table 1, a filamentous adhesive was produced in the same manner as in Example 1.

[0178] <Tensile modulus of elasticity (E) of the basic polymerp ')> The acrylic polymer emulsion 1 obtained above was applied to the release liner and allowed to dry, thus creating a 20 μm thick adhesive layer (base polymer layer) on the release liner. Multiple adhesive layers were stacked to create an adhesive layer approximately 2 mm thick. This adhesive layer was punched into a disk shape with a diameter of 7.9 mm. The resulting sample was clamped and fixed using parallel plates, and dynamic viscoelasticity was measured using a viscoelastic testing machine (trade name "ARES rheometer", manufactured by TA Instruments) at 23°C and 50% RH under the following conditions. The storage modulus G was calculated. p (23℃). It should be noted that the peak of tanδ was confirmed to exist in the range of -20 to 0℃.

[0179] Measurement mode: Shear mode Temperature range: -70℃~150℃ Heating rate: 5℃ / min Measurement frequency: 1Hz Next, based on the storage modulus (G) of the obtained basic polymer... p The tensile modulus of elasticity (E) of the base polymer is calculated using the following formula (1). p ').

[0180] G 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.

[0181] < Tensile elastic modulus of particles (E f ')> For the analytical sample, the particles used in the examples and comparative examples (commercially available products are all dispersions) were separated into dispersion medium and particles using filter paper and dried. The product formed by fixing the particles on a specified support was used as the test sample, and nanoindentation was performed.

[0182] Device: Triboindenter, manufactured by Hysitron Inc. Use of pressure plate: Berkovich (triangular pyramid) Measurement method: Single-point indentation measurement Measurement temperature: room temperature (25℃) Penetration depth: 1500nm Based on the tensile modulus (E) of the base polymer obtained by the above method p '), the tensile elastic modulus of the particle (E) f'), calculate E f ' / E p '.

[0183] <Size and content of air bubbles in adhesives> The cross-sections of the filamentous adhesives obtained in the examples and comparative examples were observed using an X-ray CT apparatus. Based on the observed images, air bubbles were extracted from the adhesive, and their sizes were measured. The bubble size was determined as the diameter using the X-ray CT apparatus. Table 1 shows the average diameter of bubbles with a diameter of 20 μm or less.

[0184] In addition, using the above-mentioned observation images, bubbles with a diameter of less than 20 μm in the adhesive were extracted, and their content (volume %) in the adhesive was determined.

[0185] 〔evaluate〕 The obtained filamentous adhesives were evaluated as described below. The results are shown in Table 1.

[0186] <Split peel strength after room temperature curing> The filamentous adhesives from the examples and comparative examples were cut into 270mm pieces. Figure 1 The vortex shape shown was adhered to a 50×30mm SUS304 board. A 30×30mm SUS clamp was then attached to it and pressed with 178N (1MPa) for 10 seconds. After standing at room temperature (23℃) for 30 minutes, the splitting peel force was measured by stretching it vertically at a peeling speed of 300mm / min. A universal testing machine (SHIMADZU, AG-X / R AG-20kNG) was used for the measurement, and the number of samples was set to n=3 or more. The average values ​​are shown in Table 1.

[0187] <Splitting and peeling force after heat aging> The SUS fixtures, to which the filamentous adhesives of the examples and comparative examples were vortex-bonded using the same steps as described above, were placed in low-temperature dryers set at the aging temperatures shown in Table 1 and kept for 1 hour. After removal, they were allowed to cool at room temperature for at least 1 hour. Then, the splitting peel force was measured according to the steps described above.

[0188] Based on the splitting peel force obtained after heat aging and the splitting peel force after room temperature curing, the ratio between them (splitting peel force after heat aging / splitting peel force after room temperature curing) is calculated. Table 1 shows the peel force ratio.

[0189] In Table 1 below, the type and amount (parts by mass) of each monomer that constitute the basic polymer are shown in the column of basic polymer.

[0190] [Table 1] The particles shown in Table 1 are described below.

[0191] PA200: Manufactured by Sumitomo Seikan Co., Ltd., trade name "SEPOLSION PA200", particle size 0.5μm, polyamide filler. • AC: Manufactured by Sumitomo Seikan Co., Ltd., trade name "ZAIKSEN AC", particle size 0.14μm, polyethylene filler. • 1571H: Manufactured by Zeon Corporation of Japan, trade name "Nipol 1571H", particle size 0.13μm, acrylonitrile butadiene rubber (NBR) filler. As shown in Table 1, the adhesive strength of the filamentous adhesives in Examples 1-7 is particularly excellent. Furthermore, since they are filamentous adhesives with a core material, their disassembly properties are also excellent.

[0192] In contrast, it can be seen that the adhesive strength of the filamentous adhesive in Comparative Example 1, which does not contain air bubbles in the adhesive layer, is poor.

[0193] <Changes in air bubbles in the adhesive before and after heat aging> The cross-section of the filamentous adhesive of Example 4 was observed using an X-ray CT device. Based on the obtained observation images, air bubbles were extracted from the adhesive, and their sizes were measured. The bubble size was determined in the form of the diameter of a sphere tangent to the void. Table 2 shows the average diameter of bubbles with a diameter of 20 μm or less. Furthermore, using the aforementioned observation images, bubbles with a diameter of 20 μm or less were extracted, and their number was counted.

[0194] The filamentous adhesive from Example 4 was placed in a low-temperature dryer set at 60°C and stored for 1 hour. The same observation was then performed to determine the size and number of air bubbles in the adhesive.

[0195] Table 2 shows the measurement results for each 2.7 mm length of the filamentous adhesive.

[0196] [Table 2] As shown in Table 2, heating and aging the filamentous adhesive increases the number of bubbles with a diameter of less than 20 μm. Furthermore, the average bubble size decreases slightly due to heating and aging, suggesting a relative increase in smaller bubbles.

[0197] Thus, it is believed that, in the case of the filamentous adhesive according to the embodiments of the present invention, the number of small bubbles increases through heating and aging, and therefore the adhesive force (split peel force) is improved as shown in Table 1.

[0198] This invention is not limited to the aforementioned embodiments, and various modifications can be made within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included within the technical scope of this invention.

[0199] Industrial availability This invention provides an adhesive material with high adhesive strength and easy disassembly.

[0200] Although the present invention has been described in detail 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 invention.

[0201] This application is based on Japanese patent application filed on March 29, 2024 (Japanese Patent Application No. 2024-057293), the contents of which are incorporated herein by reference.

Claims

1. A filamentous adhesive comprising a core material and an adhesive covering the longitudinal surface of the core material. The adhesive contains a base polymer and air bubbles.

2. The filamentous adhesive as described in claim 1, wherein, The adhesive also contains particles. The tensile modulus of the particles is more than 30 times that of the base polymer.

3. The filamentous adhesive as described in claim 2, wherein, The tensile elastic modulus of the particles is 0.01–3 GPa.

4. The filamentous adhesive as described in claim 2, wherein, The particles comprise 10 to 60 parts by mass relative to 100 parts by mass of the base polymer.

5. The filamentous adhesive as described in claim 1, wherein, The adhesive contains more than 0% and less than 5% by volume bubbles with a diameter of 20 μm or less.

6. The filamentous adhesive as described in claim 1, wherein the adhesive strength increases by heating at a temperature between 40°C and 80°C for 1 hour.

7. The filamentous adhesive as claimed in claim 1, wherein, The core material is multifilament yarn.

8. A laminate, which is a laminate of the filamentous adhesive and an electronic device component as described in any one of claims 1 to 7.

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