Threadlike adhesive body

Abstract

The present invention provides a threadlike adhesive body that is exceptional in waterproofness. The present invention relates to a threadlike adhesive body comprising a base material and an adhesive that covers the longitudinal surface of the base material, wherein the base material is provided with a core material and a water-repellent layer that covers at least part of the longitudinal surface of the core material.

Description

Thread-like adhesive body

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

[0002] A thread-like adhesive body having a core material and an adhesive is generally formed by coating the adhesive around the core material. For example, Patent Document 1 discloses a thread-like adhesive body having a strong adhesive force and a core material made of four or more multifilaments.

[0003] Such thread-like adhesives are thin and can conform to complex shapes, and therefore can be suitably used in applications where the installation space for the adhesive is limited, such as fixing linear or narrow components in a desired shape, and applications in a variety of fields are possible.

[0004] Japanese Patent Application Publication No. 2020-76066

[0005] In recent years, waterproofing has become a requirement for electronic device applications such as mobile phones and smartphones, and waterproofing (waterstopping) has also been required for thread-like adhesive bodies used to fix components in such applications. However, no consideration has been given to waterproofing for conventional thread-like adhesive bodies such as those described in Patent Document 1. Furthermore, with the miniaturization of electronic devices, thinner thread-like adhesive bodies are required for fixing components in electronic devices, and even narrow thread-like adhesive bodies are required to achieve both adhesive strength and waterproofing. However, it has been found that conventional thread-like adhesive bodies do not provide sufficient waterproofing when made narrow, and improving waterproofing has become a challenge.

[0006] The present invention has been made in view of the above-mentioned conventional circumstances, and has as its object to provide a thread-like adhesive material that is excellent in waterproofing properties.

[0007] As a result of intensive research into solving the above-mentioned problems, the inventors discovered that in a thread-like adhesive body comprising a substrate and an adhesive covering the longitudinal surface of the substrate, the above-mentioned problems can be solved by having the substrate comprise a core material and a water-repellent layer covering at least a portion of the longitudinal surface of the core material, thereby solving the present invention.

[0008] That is, the present invention relates to the following: [1] A thread-like adhesive body comprising a substrate and an adhesive covering the longitudinal surface of the substrate, wherein the substrate comprises a core material and a water-repellent layer covering at least a part of the longitudinal surface of the core material. [2] A thread-like adhesive body comprising a substrate and an adhesive covering the longitudinal surface of the substrate, wherein the surface free energy of the water-repellent layer is 10 mJ / m ２ 40mJ / m or more ２ The thread-like adhesive body according to [1], which is: [3] The thread-like adhesive body according to [1] or [2], wherein the contact angle of pure water with the water-repellent layer is 80° or more; [4] The thread-like adhesive body according to [1] or [2], wherein the core material is a multifilament yarn.

[0009] According to the present invention, a thread-like adhesive material having excellent waterproof properties can be provided.

[0010] Fig. 1 is a diagram illustrating one example of use of a thread-like adhesive body according to an embodiment of the present invention. Fig. 2 is another diagram illustrating one example of use of a thread-like adhesive body according to an embodiment of the present invention. Fig. 3 is a diagram illustrating a method for evaluating the adhesive strength of a thread-like adhesive body according to an embodiment of the present invention. Fig. 4 is a diagram illustrating a method for evaluating the adhesive strength of a thread-like adhesive body according to an embodiment of the present invention. Fig. 5 is a diagram illustrating a method for evaluating the adhesive strength of a thread-like adhesive body according to an embodiment of the present invention. Fig. 6 is a diagram illustrating a method for evaluating the waterproofness of a thread-like adhesive body according to an embodiment of the present invention. Fig. 7 is another diagram illustrating a method for evaluating the waterproofness of a thread-like adhesive body according to an embodiment of the present invention.

[0011] 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.

[0012] [Thread-like adhesive body] A thread-like adhesive body according to an embodiment of the present invention is a thread-like adhesive body comprising a substrate and an adhesive that coats the longitudinal surface of the substrate, and the substrate comprises a core material and a water-repellent layer that coats at least a portion of the longitudinal surface of the core material.

[0013] Here, thread-like means a shape in which the longitudinal length of the adhesive body is sufficiently long compared to the width direction (direction perpendicular to the longitudinal direction) and can be bent in various directions and at various angles like a thread.

[0014] The widthwise length of the thread-like adhesive body refers to the length in the thickness direction (direction perpendicular to the longitudinal direction) of the thread-like adhesive body.

[0015] In the embodiment of the present invention, the substrate of the thread-like adhesive body comprises a core material and a water-repellent layer covering at least a portion of the longitudinal surface of the core material. The presence of a water-repellent component inside the substrate prevents moisture from penetrating into the substrate due to capillary action, making it possible to provide a thread-like adhesive body that is excellent in both waterproofness and adhesive strength. When such a thread-like adhesive body is used to bond adherends together to produce a bonded structure, water is less likely to penetrate into the spatial region surrounded by the adherends and the thread-like adhesive body in the bonded structure.

[0016] Specifically, for example, as shown in Fig. 1, a thread-like adhesive body 1 according to an embodiment of the present invention is placed on the outer periphery of an open surface of a housing 2a with overlapping tip portions, and the outer periphery of the open surface of another housing 2b is pressed together to produce a joined body 10. Fig. 2 is a schematic cross-sectional view of joined body 10, and in joined body 10, water is less likely to penetrate into region Z surrounded by housings 2a, 2b and thread-like adhesive body 1.

[0017] In this specification, the waterproofness of a thread-like adhesive refers to the ability to prevent water from penetrating into the area surrounded by the adherends and the thread-like adhesive in a bonded structure in which adherends are bonded together using the thread-like adhesive.

[0018] Furthermore, since the thread-like adhesive body according to an embodiment of the present invention can be bent in various directions and angles, it can be bent to match the shape of the bonding area, and can accommodate a variety of shapes of bonding areas.

[0019] The substrate and adhesive constituting the thread-like adhesive body according to an embodiment of the present invention will be described below.

[0020] <Substrate> The adhesive thread according to an embodiment of the present invention comprises a substrate. The substrate comprises a core material and a water-repellent layer covering at least a portion of the longitudinal surface of the core material. By covering at least a portion (preferably the entire periphery) of the longitudinal surface of the core material with a water-repellent layer, it is possible to prevent moisture from penetrating into the substrate, resulting in an adhesive thread with high adhesive strength and excellent waterproofing. Furthermore, because the adhesive thread according to an embodiment of the present invention has excellent adhesive strength and waterproofing, even when it is made into a narrow adhesive thread, it is likely to achieve a waterproofing effect when used to fix components in electronic devices.

[0021] [Core Material] In the thread-like adhesive body according to the embodiment of the present invention, the core material is preferably a multifilament yarn, more preferably a multifilament yarn having four or more 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.

[0022] The number of filaments contained in the core material is preferably 4 or more, and from the viewpoint of adhesive strength, more preferably 10 or more, even more preferably 20 or more, and particularly preferably 30 or more.

[0023] 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, even more preferably 1,000 or less, and particularly preferably 500 or less.

[0024] 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.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] 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 or polygonal as long as waterproofing is ensured.

[0029] The core material may be a non-twisted multifilament yarn made by doubling four or more filaments, or may be a twisted multifilament yarn.

[0030] The core material may have four or more filaments, and may be a yarn obtained by twisting or otherwise combining a filament with a spun yarn, textured yarn, hollow yarn, etc. Examples of textured yarn include textured yarns that have been subjected to crimping or bulking processes and are generally called textured yarns, bulky yarns, and stretch yarns.

[0031] 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, but may be, for example, 200 μm or more, or 500 μm or more, or 200 μm or less, or 100 μm or less.

[0032] In an embodiment of the present invention, the core material may be either twisted or untwisted as described above, but one preferred embodiment is to use a twisted multifilament yarn as the core material. When the core material is twisted, the twist number of the core material is preferably 70 times / m or more. A twist number of 70 times / m or more reduces variation in the diameter (widthwise length) of the core material and can suppress variation in the widthwise length of the resulting filamentous adhesive body. The twist number of the core material is more preferably 80 times / m or more, and even more preferably 90 times / m or more.

[0033] On the other hand, in order to ensure that the core material is sufficiently deformed when multiple articles are bonded together and to appropriately increase the amount of adhesive attached to the substrate 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.

[0034] 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.

[0035] The twist coefficient K is preferably 24 or more, more preferably 25 or more, and even more preferably 31 or more, from the viewpoint of reducing the variation in the diameter of the core material and suppressing the variation in the width direction length of the resulting thread-like adhesive body. On the other hand, if the twist coefficient K is 120 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, and uneven portions, or narrow areas. In addition, the amount of adhesive attached per unit length can be appropriately increased. Therefore, the twist coefficient K is preferably 120 or less, more preferably 100 or less, and even more preferably 80 or less. In the thread-like adhesive body according to the embodiment of the present invention, the twist coefficient of the core material is preferably 25 to 120.

[0036]

[0037] In formula (A), K represents the twist coefficient, T represents the number of twists (turns / m), and D represents the fineness (dtex).

[0038] In an embodiment of the present invention, a preferred embodiment is one in which the core material is a braided cord. In this specification, a braided cord is a cord-like material formed by braiding multiple threads, and refers to a cord-like material in which multiple threads are regularly woven. Such a braided cord has small variation in diameter (length in the width direction). Therefore, by using a braided cord as the core material, variation in the diameter of the core material can be reduced, and variation in the length in the width direction of the resulting thread-like adhesive body can be suppressed. The braided cord may be formed by braiding multiple twisted yarns or non-twisted yarns.

[0039] In an embodiment of the present invention, from the viewpoint of variation in the length of the core material in the width direction, the number of ends of the braid is preferably 4 or more, more preferably 5 or more, and particularly preferably 6 or more. Moreover, from the viewpoint of the degree of impregnation of the adhesive into the thread-like adhesive body, the number of ends of the braid is preferably 100 or less, more preferably 95 or less, and particularly preferably 90 or less.

[0040] 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.

[0041] [Water-repellent layer] In the thread-like adhesive body according to an embodiment of the present invention, the substrate includes a water-repellent layer that covers at least a portion of the longitudinal surface of the core material. The water-repellent layer according to an embodiment of the present invention can be formed from a water-repellent agent. The water-repellent layer may cover a portion of the longitudinal surface of the core material, or may cover the entire periphery of the longitudinal surface of the core material. The entire periphery of the surface of the core material refers to the entire periphery of the core material, and refers to the entire 360° circumference of the surface of the core material, centered on the longitudinal center line of the core material.

[0042] However, the end surfaces of the core material may or may not be covered with a water-repellent layer. For example, if the thread-like adhesive body is cut during production or use, the end surfaces of the core material may not be covered with a water-repellent layer. Furthermore, if the core material is a multifilament yarn, the water-repellent layer may cover at least a portion of the surface of the multifilament yarn, or may cover the entire periphery of the surface in the longitudinal direction of the multifilament yarn.

[0043] By coating the entire longitudinal surface of the core material with a water-repellent layer, a filamentous adhesive body with better water repellency can be obtained. Furthermore, as described above, by coating the entire longitudinal surface of the core material with a water-repellent layer, moisture can be prevented from penetrating into the substrate, resulting in a filamentous adhesive body with high adhesive strength and excellent waterproofing. Furthermore, because of the excellent adhesive strength and waterproofing, even when a narrow filamentous adhesive body is formed, it is likely to achieve a waterproofing effect when used to fix components in electronic devices.

[0044] The water-repellent agent forming the water-repellent layer may be impregnated into a core material to form a water-repellent layer within the core material, which serves as a substrate. For example, if the core material is a multifilament yarn, the water-repellent agent may penetrate between multiple filaments in the core material to form a water-repellent layer. Furthermore, if the core material has voids, the water-repellent agent may penetrate into the voids in the core material to form a water-repellent layer. The presence of a water-repellent layer inside the core material further enhances the water repellency of the substrate, preventing moisture from penetrating into the core material due to capillary action, and further improving the waterproofing properties of the thread-like adhesive. Furthermore, preventing moisture from penetrating into the substrate improves the adhesion between the substrate and the adhesive, resulting in a thread-like adhesive with high adhesive strength.

[0045] The water-repellent layer according to the embodiment of the present invention has a surface free energy of 10 mJ / m ２ 40mJ / m or more ２ The surface free energy of the water-repellent layer is preferably 11 mJ / m or less. ２ More preferably, 12 mJ / m or more ２ More preferably, the surface free energy of the water-repellent layer is 10 mJ / m ２ When the surface free energy of the water-repellent layer is 40 mJ / m or more, the adhesive is not easily repelled and the adhesive has good adhesion to the surface of the core material, resulting in excellent adhesive strength. ２ When the surface free energy of the water-repellent layer is 40 mJ / m or less, the water is easily repelled and capillary action can be suppressed, resulting in excellent waterproofness. ２ If the surface free energy of the water-repellent layer is greater than 1000 kJ / cm, the layer will not repel water well and water will penetrate due to capillary action, making it difficult to achieve waterproofing. If the surface free energy of the water-repellent layer is within the above range, the thread-like adhesive material according to the embodiment of the present invention can exhibit excellent adhesive strength and waterproofing.

[0046] The surface free energy of the water-repellent layer can be adjusted, for example, by the type of water-repellent agent.

[0047] The surface free energy of the water-repellent layer according to the embodiment of the present invention is measured by the following method. A water-repellent agent is applied to the surface of a PET film (Lumirror #38, manufactured by Toray Industries, Inc.) using a wire bar, and then dried at 105°C for 2 minutes to form a water-repellent layer with a thickness of 1 μm. The resulting sheet is cut into a size of 25 mm x 100 mm to obtain a test piece. Pure water, diiodomethane, and ethylene glycol, each of which has a known surface tension, are used as test liquids, and the contact angle of each test liquid with the water-repellent layer on the test piece is measured. The surface free energy is then calculated from the obtained contact angles according to the Kitazaki-Hata method (see Kitazaki Yasuaki et al., Journal of the Japan Adhesion Association, Vol. 8, No. 3, 1972, pp. 131-141).

[0048] In this embodiment, the contact angle of pure water with the water-repellent layer is preferably 80° or more, more preferably 90° or more, and even more preferably 100° or more. When the contact angle of pure water with the water-repellent layer is 80° or more, the water is easily repelled and capillary action is easily suppressed, resulting in excellent waterproofing. When the contact angle of pure water with the water-repellent layer is less than 80°, the water is not easily repelled and water easily penetrates due to capillary action, making it difficult to achieve waterproofing.

[0049] In this embodiment, the contact angle of pure water with respect to the water-repellent layer is measured by the following method: The contact angles of diiodomethane and ethylene glycol with respect to the water-repellent layer are also measured by the same method as the contact angle of pure water.

[0050] In this embodiment, the contact angle of pure water with the water-repellent layer can be measured by the following method. First, a water-repellent agent is applied to the surface of a PET film (Lumirror #38, manufactured by Toray Industries, Inc.) using a wire bar, and then dried at 105°C for 2 minutes. The sheet, on which a water-repellent layer with a thickness of 1 μm is formed, is cut into a size of 25 mm x 100 mm to obtain a test piece. The contact angle of pure water is measured with respect to the water-repellent layer on the obtained test piece by the sessile drop method according to JIS R 3257 using a contact angle meter (DropMaster, manufactured by Kyowa Interface Science Co., Ltd.).

[0051] The water-repellent layer in this embodiment is preferably formed from a water-repellent agent. The type of water-repellent agent is not particularly limited, and examples thereof include hydrocarbon-based water-repellent agents such as urethane-based water-repellent agents, acrylic-based water-repellent agents, fluorine-based water-repellent agents, and silicone-based water-repellent agents. These water-repellent agents may be used by blending them with a crosslinking agent.

[0052] Examples of hydrocarbon-based water repellents include urethane-based compounds, polyethylene-based compounds, paraffin-based compounds, metal salts of polymer wax emulsions, octadecylethyleneurea, fatty acid esters, and polyamide compounds.

[0053] Examples of the acrylic water repellent include those containing a polymer containing a structural unit derived from a (meth)acrylic acid ester monomer (A) (hereinafter also referred to as "component (A)") represented by the following general formula (A-1):

[0054]

[0055] [In formula (A-1), R １ represents hydrogen or a methyl group, R ２ represents a monovalent hydrocarbon group having 12 or more carbon atoms which may have a substituent.

[0056] Here, "(meth)acrylic acid ester" means "acrylic acid ester" or the corresponding "methacrylic acid ester", and has the same meaning as "(meth)acrylic acid", "(meth)acrylamide", etc.

[0057] The (meth)acrylic acid ester monomer (A) used in this embodiment and represented by the general formula (A-1) has a monovalent hydrocarbon group having 12 or more carbon atoms which may have a substituent. This hydrocarbon group may be linear or branched, may be a saturated or unsaturated hydrocarbon group, and may further have an alicyclic or aromatic ring. Among these, linear groups are preferred, and linear alkyl groups are more preferred. In this case, the water repellency is more excellent. When the monovalent hydrocarbon group having 12 or more carbon atoms has a substituent, examples of the substituent include one or more of a hydroxyl group, an amino group, a carboxyl group, an epoxy group, an isocyanate group, a blocked isocyanate group, and a (meth)acryloyloxy group. In this embodiment, in the general formula (A-1), R ２ is preferably an unsubstituted hydrocarbon group.

[0058] Examples of fluorine-based water repellents include fluorine-based resins, such as PTFE (polytetrafluoroethylene) (e.g., "Teflon" (registered trademark)), FEP (tetrafluoroethylene hexafluoropropylene copolymer), PFA (perfluoroalkoxy fluorinated resin), ETFA (ethylene tetrafluoroethylene copolymer), PVDF (polyvinylidene fluoride), PVF (polyvinyl fluoride), etc., or mixtures thereof.

[0059] Examples of silicone-based water repellents include silicone resins and silicone oils. Silicone resins include, for example, R ３ SiO １／２ Structural unit: SiO ２ Structural unit: RSiO ３／２ Structural units and R ２Examples of silicone oils that can be used include organopolysiloxanes containing at least one structural unit selected from SiO structural units (R is a monovalent hydrocarbon group or a hydroxyl group). Examples of silicone oils that can be used include straight silicone oils such as dimethylsilicone oil, methylphenylsilicone oil, and methylhydrogensilicone oil; modified silicone oils such as amino-modified silicone oil, epoxy-modified silicone oil, carbinol-modified silicone oil, mercapto-modified silicone oil, carboxyl-modified silicone oil, polyether-modified silicone oil, alkyl-modified silicone oil, aralkyl-modified silicone oil, alkylaralkyl-modified silicone oil, higher fatty acid ester-modified silicone oil, and higher aliphatic amide-modified silicone oil; and mixtures thereof.

[0060] Furthermore, in the thread-like adhesive body according to an embodiment of the present invention, the amount of water repellent agent attached to the core material is, from the viewpoint of ensuring waterproofness and adhesive strength, preferably 0.02 or more, more preferably 0.03 or more, and particularly preferably 0.04 or more by mass ratio (water repellent agent / core material) of the water repellent layer to the core material, and is preferably 0.4 or less, more preferably 0.3 or less, and particularly preferably 0.2 or less.

[0061] [Adhesive] The thread-like adhesive body according to an embodiment of the present invention has an adhesive that coats the substrate. The adhesive in 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).

[0062] The adhesive preferably covers the entire periphery of the surface of the substrate in the longitudinal direction. The entire periphery of the surface of the substrate refers to the entire peripheral surface of the substrate, and means the entire 360° circumference of the surface of the substrate, centered on the center line of the substrate in the longitudinal direction.

[0063] However, the end faces of the substrate may or may not be coated with an adhesive. For example, if the adhesive threads are cut during production or use, the end faces of the substrate may not be coated with an adhesive.

[0064] By coating the entire longitudinal surface of the substrate with an adhesive, a thread-like adhesive body with excellent strength can be obtained. This is presumably because the substrate is not exposed on the surface, preventing stress from concentrating on a part of the substrate and causing breakage. Furthermore, by coating the entire longitudinal surface of the substrate with an adhesive, gaps are less likely to occur at the bonded portion between the thread-like adhesive body and the adherend, resulting in a thread-like adhesive body with excellent waterproofing.

[0065] The adhesive forming the adhesive layer may be impregnated into the substrate. Here, "the adhesive is impregnated into the substrate" means that the adhesive is present between multiple filaments in the core material. When the adhesive is impregnated into the substrate, the adhesive and the substrate maintain adhesion, making them less likely to peel off, and improving the strength of the thread-like adhesive body.

[0066] The adhesive in this embodiment is preferably formed from an adhesive containing a base polymer as a main component. The type of adhesive is not particularly limited, and examples thereof include acrylic adhesives, rubber adhesives, vinyl alkyl ether adhesives, silicone adhesives, polyester adhesives, polyamide adhesives, urethane adhesives, fluorine adhesives, and epoxy adhesives.

[0067] 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. In this embodiment, the adhesive is preferably an acrylic adhesive.

[0068] 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.

[0069] 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.

[0070] 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.

[0071] 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 ".

[0072] 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, ...

[0073] 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.

[0074] 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).

[0075] 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.

[0076] 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. On the other hand, from the viewpoint of cohesive strength, etc., the proportion of C in the monomer components is preferably 100% 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).

[0077] 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).

[0078] In another preferred embodiment, the adhesive composition contains at least one selected from the group consisting of an alkyl(meth)acrylate having a linear alkyl group having 1 to 3 carbon atoms, an alkyl(meth)acrylate having a branched alkyl group having 3 or 4 carbon atoms, and an alicyclic monomer. That is, it is also preferred that the adhesive composition forming the adhesive contains an acrylic polymer, and that the acrylic polymer contains, as a monomer component, at least one selected from the group consisting of an alkyl(meth)acrylate having a linear alkyl group having 1 to 3 carbon atoms, an alkyl(meth)acrylate having a branched alkyl group having 3 or 4 carbon atoms, and an alicyclic monomer.

[0079] Homopolymers of these monomers have relatively high Tg, and hereinafter these monomers are also referred to as high Tg monomers.

[0080] The alicyclic monomer is preferably a cycloalkyl(meth)acrylate having a cycloalkyl group having 4 to 10 carbon atoms which may have a substituent (for example, a linear or branched alkyl group having 1 to 6 carbon atoms), more preferably a cycloalkyl acrylate having a cycloalkyl group having 4 to 10 carbon atoms which may have a substituent (for example, a linear or branched alkyl group having 1 to 6 carbon atoms), and particularly preferably cyclohexyl acrylate or 3,3,5-trimethylcyclohexyl (meth)acrylate.

[0081] As the alkyl (meth)acrylate having a linear alkyl group with 1 to 3 carbon atoms, an alkyl acrylate having a linear alkyl group with 1 to 3 carbon atoms is preferred, and methyl acrylate is particularly preferred.

[0082] As the alkyl (meth)acrylate having a branched alkyl group with 3 or 4 carbon atoms, an alkyl acrylate having a branched alkyl group with 3 or 4 carbon atoms is preferred, and t-butyl acrylate is particularly preferred.

[0083] Among them, the high Tg monomer is preferably an alkyl acrylate having a linear alkyl group with 1 to 3 carbon atoms, and methyl acrylate is particularly preferred.

[0084] In an embodiment in which a high Tg monomer is copolymerized with an acrylic polymer, the total amount of the high Tg monomer relative to the total amount of the monomer components constituting the acrylic polymer is preferably 1% by mass or more, more preferably 3% by mass or more, and even more preferably 5% by mass or more. Furthermore, from the viewpoint of suppressing a decrease in the adhesive strength of the PSA, it is preferably 20% by mass or less, more preferably 18% by mass or less, and even more preferably 15% by mass or less. That is, the total amount of at least one monomer selected from the group consisting of alkyl(meth)acrylates having a linear alkyl group with 1 to 3 carbon atoms, alkyl(meth)acrylates having a branched alkyl group with 3 or 4 carbon atoms, and alicyclic monomers is preferably 1 to 20% by mass relative to the total amount of the monomer components constituting the acrylic polymer.

[0085] 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.

[0086] 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.

[0087] 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.

[0088] 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.

[0089] 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.

[0090] 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.

[0091] The adhesive may also 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, as appropriate.

[0092] 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.

[0093] 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.

[0094] 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.

[0095] 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.

[0096] 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.

[0097] The pressure-sensitive adhesive according to the present embodiment may preferably use a tackifying resin. Any appropriate tackifying resin may be used as the tackifying resin. 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-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.

[0098] 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.

[0099] The adhesive composition that forms the adhesive 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.

[0100] The PSA composition may be either a solvent-based PSA or a water-dispersed PSA. A water-dispersed PSA composition is preferred because it allows high-speed coating, is environmentally friendly, and minimizes the impact of the solvent on the core material (swelling, dissolution). In an embodiment of the present invention, the PSA is preferably an acrylic emulsion PSA containing a water-dispersed acrylic polymer.

[0101] 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.

[0102] The amount of adhesive attached is preferably 10% by mass or more, more preferably 20% by mass or more, and particularly preferably 30% by mass or more, relative to the core material, from the viewpoints of ensuring waterproofness and adhesive strength. Furthermore, from the viewpoints of suppressing variation in the width direction length of the thread-like adhesive bodies and suppressing a decrease in the strength of the thread-like adhesive bodies, the amount is preferably 90% by mass or less, more preferably 80% by mass or less, and particularly preferably 70% by mass or less. In this embodiment, the amount of adhesive attached is preferably 20 to 80% by mass relative to the core material.

[0103] From the viewpoints of strength and handleability, the width of the thread-like adhesive body according to the embodiment of the present invention is preferably 50 μm or more, more preferably 100 μm or more, and is preferably 2000 μm or less, more preferably 1000 μm or less.

[0104] In an embodiment of the present invention, the average width of the adhesive threads is the average of the width lengths measured at 10 points at 1 cm intervals along the longitudinal direction of the adhesive threads under a microscope. The maximum width length of the adhesive threads is used.

[0105] Specifically, first, a ruler is placed on the stage of the microscope and the scale is calibrated. Then, the adhesive filaments are placed and their position is finely adjusted so that the latitude lines of the grid-like scale displayed on the observation screen are parallel to the long axis of the adhesive filaments. Next, the observation magnification of the microscope is set to 30 times, and the length of the short axis (length in the width direction) of the adhesive filaments is measured at 10 points at 1 cm intervals in the longitudinal direction. The obtained measurement values ​​(X １ , X ２ ,...,X １０ ) to calculate the average value m (average value of the length of the thread-like adhesive body in the width direction).

[0106] [Method for manufacturing thread-like adhesive body] The thread-like adhesive body according to the embodiment of the present invention can be manufactured by a known method. For example, the substrate can be manufactured by a method including a water-repellent layer forming step of forming a water-repellent layer on at least a portion of the longitudinal surface of the core material. The thread-like adhesive body according to the embodiment of the present invention can be manufactured by a method including an adhesive coating step of coating the substrate with a coating liquid containing an adhesive.

[0107] A method for manufacturing a thread-like adhesive body according to an embodiment of the present invention is a method for manufacturing a thread-like adhesive body comprising a substrate and an adhesive that coats the longitudinal surface of the substrate, and can be manufactured by a method including a water-repellent layer formation process for forming a water-repellent layer on at least a portion of the longitudinal surface of the core material, and an adhesive coating process for coating a coating liquid containing an adhesive on the longitudinal surface of the substrate.

[0108] The water repellent agent may be applied to the surface of the core material in the longitudinal direction once or multiple times.

[0109] The water repellent agent may be applied to the core material by, for example, dipping, immersion, coating, or the like, and then heated and dried as necessary. Heat drying may be carried out, for example, at 80 to 120°C, preferably 90 to 110°C, for example, for 20 seconds to 3 minutes, preferably 30 seconds to 2 minutes.

[0110] The water repellent agent 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, a spray coater, or a die coater.

[0111] The method for producing a substrate according to an embodiment of the present invention may or may not include a fiber-opening step. In the fiber-opening step, the core material is opened by running the core material along a non-rotating roller when the water repellent agent is applied to the core material. When a substrate according to an embodiment of the present invention is produced without the fiber-opening step, the porosity in the substrate can be adjusted to be high. On the other hand, when a substrate according to an embodiment of the present invention is produced with the fiber-opening step, the porosity in the substrate can be adjusted to be low.

[0112] Furthermore, when the method for producing a substrate according to an embodiment of the present invention includes a water-repellent layer-forming step, a roller is used in the water-repellent layer-forming step, and the rotation speed of the roller is preferably 0.3 to 5.0 times the payout speed of the core material, more preferably 0.4 to 4.0 times, even more preferably 0.5 to 3.0 times, and particularly preferably 0.8 to 1.5 times the payout speed of the core material.

[0113] In the water-repellent layer forming step, it is preferable to apply a tension of 12.0 mN / dtex or less to the core material, preferably 0.2 to 12.0 mN / dtex, more preferably 0.4 to 10.0 mN / dtex.

[0114] The adhesive coating solution containing an adhesive may be applied to the surface of the substrate in the longitudinal direction once or multiple times.

[0115] The adhesive coating solution may be applied to the substrate by, for example, dipping, immersion, coating, or the like, and may be dried by heating as necessary. Heat drying may be carried out, for example, at 80 to 120°C, preferably 90 to 110°C, for 20 seconds to 3 minutes, preferably 30 seconds to 2 minutes.

[0116] The adhesive coating solution can be applied using a conventional coater such as a gravure roll coater, reverse roll coater, kiss roll coater, dip roll coater, bar coater, knife coater, spray coater, or die coater.

[0117] Furthermore, when the method for producing a thread-like adhesive body according to an embodiment of the present invention includes a pressure-sensitive adhesive coating step, the pressure-sensitive adhesive coating step preferably uses a roller, and the rotation speed of the roller is 0.3 to 5.0 times the feed speed of the substrate, more preferably 0.4 to 4.0 times, even more preferably 0.5 to 3.0 times, and particularly preferably 0.8 to 1.5 times the feed speed of the substrate.

[0118] In addition, in the adhesive coating step, it is preferable to apply a tension of 6.0 mN / dtex or less to the substrate, preferably 0.2 to 6.0 mN / dtex, more preferably 0.4 to 5.0 mN / dtex.

[0119] One preferred aspect of the thread-like adhesive body according to an embodiment of the present invention is that it includes, after the adhesive coating step, a threading step in which the substrate coated with the adhesive coating liquid is threaded through a cylindrical or comb-shaped gap.

[0120] For example, when a pressure-sensitive adhesive coating liquid is applied to a substrate by dipping, the amount of adhesive coating liquid adhered to the substrate may be relatively large, and the amount of adhesive coating liquid adhered to the substrate may become uneven due to the influence of gravity during transport, adhesion to the rollers used, etc. Therefore, by threading a core material coated with the pressure-sensitive adhesive coating liquid through a cylinder having a constant inner diameter, the unevenly adhered coating liquid can be leveled out, and variation in the widthwise length of the resulting thread-like adhesive body can be suppressed.

[0121] [Uses of adhesive threads] The adhesive threads according to the embodiments of the present invention have excellent waterproof properties, and therefore can be used to adhere articles that require waterproofing and sealing properties. For example, in the manufacture of electronic devices, adhesive threads according to the embodiments of the present invention can be used to prevent water from entering into a housing (e.g., housing 2a in FIG. 1 ) containing components that should be prevented from entering into water, such as a battery or a circuit board, by adhering the housing to another member (e.g., housing 2b in FIG. 1 ).

[0122] Furthermore, the adhesive thread according to the embodiment of the present invention can be attached to narrow members or narrow areas while preventing overhang, and is easily applicable to complex shapes such as curves, curved surfaces, and uneven surfaces, and is also preferable in that it can be easily disassembled (reworked). Furthermore, due to its excellent adhesive strength, it can be used to adhere various items.

[0123] Furthermore, for example, when applying an adhesive tape to an adherend having a complex shape, such as a curve, a curved surface, or an uneven surface, wrinkles and overlaps may 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 waterproofness and adhesive strength. To apply an adhesive tape without wrinkles or overlaps, it is possible to cut the adhesive tape into small pieces before application, but this significantly reduces workability and makes it difficult to achieve the desired waterproofness. 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, and can exhibit excellent waterproofness. Furthermore, since such adhesive threads can be applied to the desired areas at once, i.e., in a single process, they are easy to work with and can be applied to automated lines.

[0124] Furthermore, the thread-like adhesive material according to the embodiment of the present invention can be suitably used for the purpose of temporarily fixing (temporarily fastening) one article to the surface of another article. Furthermore, with the thread-like adhesive material according to the embodiment of the present invention, after the two articles have been fixed (fully fixed), it is easy to remove the thread-like adhesive material according to the embodiment of the present invention from between the two fixed (fully fixed) articles, as needed.

[0125] As described above, the present specification discloses the following: [1] A thread-like adhesive body comprising a substrate and an adhesive covering a longitudinal surface of the substrate, wherein the substrate comprises a core material and a water-repellent layer covering at least a portion of the longitudinal surface of the core material. [2] A thread-like adhesive body comprising a substrate and an adhesive covering a longitudinal surface of the substrate, wherein the surface free energy of the water-repellent layer is 10 mJ / m ２ 40mJ / m or more ２ The thread-like adhesive body according to [1], which is: [3] The thread-like adhesive body according to [1] or [2], wherein the contact angle of pure water with the water-repellent layer is 80° or more; [4] The thread-like adhesive body according to any one of [1] to [3], wherein the core material is a multifilament yarn.

[0126] 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.

[0127] <Preparation of Water-Dispersible Acrylic Pressure-Sensitive Adhesive> 40 parts by mass of ion-exchanged water was placed in a reaction vessel equipped with a cooling tube, a nitrogen inlet tube, a thermometer, and a stirrer, and nitrogen substitution was carried out by stirring at 60°C for at least 1 hour while introducing nitrogen gas. 0.1 parts by mass of 2,2'-azobis[N-(2-carboxyethyl)-2-methylpropionamidine] n-hydrate (polymerization initiator) was added to this reaction vessel. While maintaining the system at 60°C, Monomer Emulsion A was gradually added dropwise over 4 hours to allow the emulsion polymerization reaction to proceed.

[0128] Monomer emulsion A was prepared by adding 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), 0.05 parts by mass of lauryl mercaptan (chain transfer agent), 0.02 parts by mass of γ-methacryloxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., trade name "KBM-503"), and 2 parts by mass of sodium polyoxyethylene lauryl sulfate (emulsifier) ​​to 30 parts by mass of ion-exchanged water and emulsifying the mixture. After the dropwise addition of monomer emulsion A was completed, the system was maintained at 60°C for an additional 3 hours, cooled to room temperature, and then the pH was adjusted to 7 by adding 10% aqueous ammonia, thereby obtaining acrylic polymer emulsion (water-dispersed acrylic polymer) A.

[0129] Per 100 parts by mass of the acrylic polymer contained in the acrylic polymer emulsion A, 35 parts by mass (solids basis) of a tackifier resin emulsion (manufactured by Arakawa Chemical Industries, Ltd., product name "E-200NT") was added. Furthermore, the pH was adjusted to 9.0 and the viscosity to 10 Pa s using 10 mass% ammonia water as a pH adjuster and polyacrylic acid (manufactured by Toagosei Co., Ltd., product name "Aron B-500") as a thickener. In this way, a water-dispersible acrylic pressure-sensitive adhesive 1 for use as a pressure-sensitive adhesive was obtained.

[0130] <Production of Thread-Like Adhesive> (Example 1) A core material was a multifilament yarn obtained by twisting one polyethylene terephthalate (PET) fiber (manufactured by Teijin Frontier Co., Ltd.) (fineness: 167 dtex, number of filaments: 48) 200 times per meter. The multifilament yarn was coated with a urethane-based water repellent (Z-71 manufactured by Meisei Chemical Industry Co., Ltd.) using a coating machine in an amount of water repellent as shown in Table 1, and dried at 100°C for 1 minute to form a water-repellent layer, thereby obtaining a substrate. The obtained substrate was coated with water-dispersible acrylic adhesive 1 by dipping using a coating roller. The substrate was then dried at 100°C for 1 minute to obtain a thread-like adhesive having a glue amount (adhesive amount) (11.0 mg / 60 cm) as shown in Table 1.

[0131] (Example 2) The core material was changed to a multifilament yarn consisting of seven polyethylene terephthalate (PET) fibers (manufactured by Teijin Frontier Co., Ltd.) with a fineness of 167 dtex and a number of filaments of 48 (fineness: 1169 dtex, number of filaments: 336) twisted 150 times per meter, and a thread-like adhesive body with the amount of glue listed in Table 1 was produced using the same procedure as in Example 1.

[0132] (Examples 3 to 9) The thread-like adhesive bodies of Examples 3 to 9 were prepared in the same manner as Example 1, except that the type of water repellent, the amount of water repellent, and the amount of glue were changed as shown in Tables 1 and 2, respectively.

[0133] (Comparative Example 1) A thread-like adhesive body of Comparative Example 1 with the amount of adhesive listed in Table 2 was prepared in the same manner as Example 1, except that a water-repellent layer was not formed on the surface of the core material and water-dispersible acrylic adhesive 1 was applied to the surface of the core material.

[0134] (Comparative Example 2) Five parts by mass of a silicone-based water repellent (E-790 manufactured by Nissin Chemical Industry Co., Ltd.) was added to 100 parts by mass of the resin component in the water-dispersible acrylic pressure-sensitive adhesive 1 to obtain a water-dispersible acrylic pressure-sensitive adhesive 2. A thread-like adhesive body of Comparative Example 2 having the adhesive amount shown in Table 2 was produced in the same manner as in Example 1, except that a water-repellent layer was not formed on the surface of the core material, and the water-dispersible acrylic pressure-sensitive adhesive 2 was applied to the surface of the core material.

[0135] <Characteristics of the Thread-like Adhesive> (Contact Angle with Water-Repellent Layer and Surface Free Energy of Water-Repellent Layer) The water-repellent agent used in the examples was applied to the surface of a PET film (Lumirror #38, manufactured by Toray Industries, Inc.) using a wire bar, and then dried at 105°C for 2 minutes to form a water-repellent layer with a thickness of 1 μm. The prepared sheet was cut into a size of 25 mm x 100 mm to obtain a test piece 1. Pure water, diiodomethane, and ethylene glycol, each with a known surface tension, were used as test liquids, and the contact angle of each test liquid with the water-repellent layer 1 on the test piece was measured. The surface free energy of the water-repellent layer was then calculated from the obtained contact angle according to the Kitazaki-Hata method (see Kitazaki Yasuaki et al., Journal of the Japan Adhesion Association, Vol. 8, No. 3, 1972, pp. 131-141). The contact angle of the water-repellent layer on the obtained test piece was measured using a contact angle meter (DropMaster, manufactured by Kyowa Interface Science Co., Ltd.) by the sessile drop method in accordance with JIS R 3257. In Comparative Examples 1 and 2, since no water-repellent layer was provided, the contact angle of the surface of a PET film (Lumirror #38, manufactured by Toray Industries, Inc.) not coated with a water-repellent material was measured with each test liquid in the same manner as above, and the surface free energy was determined.

[0136] (Adhesion Strength Evaluation) The water repellent agents used in the Examples and Comparative Examples were each applied to the surface of a PET film (Lumirror #38, manufactured by Toray Industries, Inc.) using a wire bar, followed by drying at 105°C for 2 minutes. A water-dispersible acrylic pressure-sensitive adhesive 1 was applied to the resulting water-repellent layer, followed by drying at 105°C for 2 minutes. The adhesive surface of a pressure-sensitive adhesive tape (BT-315, manufactured by Nitto Denko Corporation) was attached to the resulting pressure-sensitive adhesive layer, followed by aging at room temperature for 30 minutes. Each of the prepared sheets was cut into a size of 25 mm x 100 mm to prepare a test specimen. The prepared test specimens were subjected to 180° peeling at a speed of 300 m / min using a Tensilon under conditions of 23°C x 50% RH, and the peel strength was measured to determine the adhesion strength between the substrate having a water-repellent layer and the pressure-sensitive adhesive layer (PET was not corona-treated). In Comparative Example 2, the water-dispersible acrylic pressure-sensitive adhesive 1 was applied to the surface of a PET film (Lumirror #38, manufactured by Toray Industries, Inc.) that did not have a water-repellent layer and was therefore not coated with a water-repellent material, and the adhesion strength was evaluated in the same manner as above.

[0137] Each test piece was prepared in the same manner as above, except that the surface of a PET film (Lumirror #38, manufactured by Toray Industries, Inc.) was subjected to corona treatment at an output of 0.07 W, and the adhesion strength between the substrate having a water-repellent layer and the pressure-sensitive adhesive layer (with corona treatment on PET) was measured.

[0138] (Amount of adhesive and amount of adhesive attached to substrate (or core material)) The amount of adhesive was calculated from the mass per unit length of the substrate (or core material) W1 [mg / m] and the mass per unit length of the thread-like adhesive body after coating and drying W2 [mg / m] using the following formula (2): Amount of adhesive [mg / m] = W2 [mg / m] - W1 [mg / m] (2)

[0139] (Diameter (width length) of thread-like adhesive body) The thread-like adhesive bodies of the examples and comparative examples were observed under a microscope, and the width length (length perpendicular to the longitudinal direction) of the thread-like adhesive body was measured at 10 points at 1 cm intervals in the longitudinal direction, and the average value was calculated to be the diameter (μm) of the thread-like adhesive body. Specifically, the thread-like adhesive body was first placed on the stage of the microscope, and its position was finely adjusted so that the latitude lines of the grid-like scale displayed on the observation screen were parallel to the long axis of the thread-like adhesive body. The observation magnification of the microscope was set to 30x, and the length of the short axis (width length) of the thread-like adhesive body was measured at 10 points at 1 cm intervals in the longitudinal direction. The maximum value at each measurement point was used as the width length of the thread-like adhesive body.

[0140] (Capillary Action) The substrate (core material with a water-repellent layer formed thereon) or core material used in each example was cut to a length of 10 cm and placed on a polycarbonate plate so as not to bend the substrate or core material. A drop of red-colored water was dropped onto one end of the substrate or core material, and after one minute the distance traveled by the colored water in the longitudinal direction of the substrate or core material due to capillary action was measured. The measurement results were evaluated according to the following evaluation criteria 1 to 5 and are shown in the table. (Capillary Action Criteria) 5: 0 cm 4: More than 0 cm and 1.5 cm or less 3: More than 1.5 cm and 3.0 cm or less 2: More than 3.0 cm and 4.5 cm or less 1: More than 4.5 cm and 10 cm or less

[0141] (Adhesive Strength) The adhesive strength of the thread-like adhesive body was evaluated using the cleavage peel force described below. Figures 3 to 5 are diagrams illustrating a method for evaluating the adhesive strength of a thread-like adhesive body according to an embodiment of the present invention. The obtained thread-like adhesive body 40 was arranged on a stainless steel (SUS) plate 3a (W (mm) x D (mm) x H (mm) = 30 x 60 x 2) in a spiral shape with an outer diameter of 25 mm, 5 circumferences, a pitch distance of 1.5 mm, and a usage length of 27 cm, as shown in Figure 3. On top of this, a SUS plate 3b (W (mm) x D (mm) x H (mm) = 30 x 30 x 3) was placed as shown in Figure 4, and the resulting mixture was pressed with a press under a pressure of 0.35 MPa for 10 seconds to obtain a bonded body 20 for evaluation. The obtained bonded body 20 for evaluation was set in a tensile tester (Shimadzu Autograph AG-100M2 manufactured by Shimadzu Corporation), and peeled in a direction perpendicular to the plane of the plate 3b as shown in FIG. 5 under conditions of 23°C and a tensile speed of 300 mm / min, and the obtained stress value was defined as the adhesive strength (MPa).

[0142] (Waterproofing) Using each example of the thread-like adhesive material, a test piece was prepared by bonding a polycarbonate (PC) resin plate (3 cm on each side) to a larger PC resin plate (4 cm on each side, square). Specifically, as shown in FIG. 6, a thread-like adhesive material 1 was first placed on one polycarbonate resin plate 4a in a square shape with a side length X of 2.5 cm and an overlap Y of 1 cm at the tip ends of the thread-like adhesive material. A nonwoven fabric 5 (1 cm square) was then placed inside the square, and the other PC resin plate 4b was then laminated on top of it as shown in FIG. 7. The resulting bonded structure was then pressed under a pressure of 0.35 MPa for 10 seconds using a press to obtain a bonded structure for evaluation. The resulting test piece was then placed in a water bath, held at a depth of 1 m for 30 minutes, and observed. Evaluation criteria 1 to 5 were used. If water did not penetrate into the area (inside) surrounded by the thread-like adhesive body of the test piece, it was deemed not hydrophilic. Furthermore, a rating of 2 to 5 on the following criteria indicates sufficient waterproofing. (Waterproofing Evaluation Criteria) 5: No water penetration for 30 minutes 4: Slight water penetration for 30 minutes 3: Water penetration to the inside for 20 to less than 30 minutes 2: Water penetration to the inside for 10 to less than 20 minutes 1: Water penetration to the inside for less than 10 minutes

[0143] The results obtained above are shown in Tables 1 and 2. In Tables 1 and 2 below, the polymer column shows the monomer type and amount (parts by mass) of each monomer constituting the polymer. Also, "parts" means "parts by mass."

[0144]

[0145]

[0146] The abbreviations for the water repellents in Tables 1 and 2 are as follows: (Water repellents) E-790: Silicone-based water repellent (nonionic surfactant, manufactured by Nissin Chemical Industry Co., Ltd.) 1827: Silicone-based water repellent (nonionic surfactant, manufactured by Nissin Chemical Industry Co., Ltd.) AG-E-550D: Fluorine-based water repellent (nonionic surfactant, manufactured by AGC Inc.) Z-71: Hydrocarbon-based water repellent (cationic surfactant, manufactured by Meisei Chemical Industry Co., Ltd.) Z-100: Hydrocarbon-based water repellent (cationic surfactant, manufactured by Meisei Chemical Industry Co., Ltd.) P-900N: Acrylic-based water repellent (nonionic surfactant, manufactured by Meisei Chemical Industry Co., Ltd.)

[0147] The results shown in Tables 1 and 2 demonstrate that the thread-like adhesive bodies of Examples 1 to 9, which had a water-repellent layer on the surface of the core material, were excellent in waterproofing. They also had sufficient adhesive strength as thread-like adhesive bodies. In contrast, the thread-like adhesive bodies of Comparative Examples 1 and 2, which did not have a water-repellent layer on the surface of the core material, did not achieve the desired waterproofing.

[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] By using the thread-like adhesive material of the present invention, it is possible to provide a thread-like adhesive material having excellent waterproof properties.

[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. 2023-221225) filed on December 27, 2023, the contents of which are incorporated herein by reference.

[0151] 1, 40 Thread-like adhesive body 2a, 2b Housing 3a, 3b Board 4a, 4b Resin board 5 Nonwoven fabric 10, 20 Joined body

Claims

1. A filamentary adhesive body comprising a base material and an adhesive that coats the longitudinal surface of the base material, wherein the base material comprises a core material and a water-repellent layer that coats at least a part of the longitudinal surface of the core material.

2. The surface free energy of the water-repellent layer is 10 mJ / m ２ or more and 40 mJ / m ２ or less. The filamentary adhesive body according to claim 1.

3. The filamentary adhesive body according to claim 1 or 2, wherein the contact angle of pure water with respect to the water-repellent layer is 80° or more.

4. The filamentary adhesive body according to claim 1 or 2, wherein the core material is a multifilament yarn.

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