Filamentous adhesive and method for manufacturing filamentous adhesive

Abstract

The objective of this invention is to provide a filamentous adhesive with high impact resistance. This invention relates to a filamentous adhesive comprising an adhesive and a core material having multiple filaments, wherein the adhesive coats and is impregnated within the core material, and the filamentous adhesive contains 1 to 55% by volume porosity.

Description

Technical Field

[0001] This invention relates to filamentous adhesives and methods for manufacturing filamentous adhesives. Background Technology

[0002] When bonding two or more items, adhesives such as double-sided adhesive tape are sometimes used. However, double-sided adhesive tape usually has a certain width, making it unsuitable for situations where the items to be bonded have complex shapes or where the bonding area is narrow.

[0003] Therefore, double-sided adhesive tape with a narrower width was used, and double-sided adhesive tape was cut into the desired shape by punching.

[0004] However, double-sided adhesive tape cut into narrower widths suffers from problems such as low reworkability due to insufficient substrate strength, unsuitability for application to curved objects, and susceptibility to twisting. On the other hand, while double-sided adhesive tape cut into the desired shape through die-cutting does not have these problems, it suffers from time-consuming processing and higher costs due to the large amount of waste generated during processing.

[0005] To address the problems described above, filamentous adhesives were used. Filamentous adhesives offer high reworkability, can be deformed into various shapes, and avoid the deterioration in workability caused by twisting, as they do not have an inside-outside concept. Furthermore, filamentous adhesives are easy to process and are cost-effective.

[0006] As a filamentous adhesive, for example, Patent Document 1 discloses a filamentous adhesive characterized by attaching an adhesive to a filamentous core material.

[0007] Existing technical documents

[0008] Patent documents

[0009] Patent Document 1: Japanese Patent Application Publication No. 03-231980 Summary of the Invention

[0010] The problem that the invention aims to solve

[0011] However, according to the inventors' research, conventional filamentous adhesives as disclosed in Patent Document 1 have the problem of low impact resistance.

[0012] The present invention was made in view of the above-mentioned prior art, and the problem to be solved is to provide a filamentous adhesive with high impact resistance.

[0013] Methods for solving problems

[0014] The inventors of this application conducted repeated and in-depth research to solve the above-mentioned problems, and as a result, they discovered that by making the filamentous adhesive have voids, the above-mentioned problems could be solved, thus completing the present invention.

[0015] That is, the present invention relates to the following <1> ~ <7> .

[0016] <1> A filamentous adhesive is a filamentous adhesive containing an adhesive and a core material with multiple long filaments.

[0017] The aforementioned adhesive coats and is impregnated within the aforementioned core material.

[0018] The aforementioned filamentous adhesive contains 1 to 55% by volume voids.

[0019] <2> like <1> The filamentous adhesive described herein satisfies the following formula (1).

[0020] a / b≥2 (1)

[0021] In equation (1), a refers to the length of the longest straight line that can be placed in the gap, and b refers to the length of the widest part of the cross section obtained by cutting the filamentous adhesive perpendicular to the long side direction.

[0022] <3> like <1> or <2> The aforementioned filamentous adhesive, wherein the core material has a twist count of 1 to 500 twists / m.

[0023] <4> A method for manufacturing a filamentous adhesive, comprising an adhesive and a core material having multiple filaments, wherein...

[0024] This includes a coating process of applying a coating liquid containing the aforementioned adhesive to the aforementioned core material.

[0025] Excluding the fiber opening process.

[0026] <5> like <4> The method for manufacturing the filamentous adhesive, wherein a roller is used in the aforementioned coating process.

[0027] The rotational speed of the aforementioned roller is 0.3 to 5.0 times the extraction speed of the aforementioned core material.

[0028] <6> like <4> or <5> The method for manufacturing the filamentous adhesive, wherein, in the aforementioned coating process, a tension of 6.0 mN / dtex or less is applied to the aforementioned core material.

[0029] <7> like <4> ~ <6> In any one of the methods for manufacturing the filamentous adhesive, the viscosity of the coating liquid at a shear rate of 100 (1 / s) is 0.03 to 6 Pa·s, and the viscosity of the coating liquid at a shear rate of 0.1 (1 / s) is 2 to 140 Pa·s.

[0030] Invention Effects

[0031] The filamentous adhesive of the present invention has high impact resistance and excellent reworkability. Attached Figure Description

[0032] [ Figure 1 ] Figure 1 This is a cross-sectional photograph of the filamentous adhesive obtained in Example 2.

[0033] [ Figure 2 ] Figure 2 This is a schematic diagram of the joint used for impact resistance evaluation in the embodiment. Detailed Implementation

[0034] The embodiments of the present invention will now be described in more detail, but the present invention is not limited to any of the embodiments described below.

[0035] [Filamentous adhesive]

[0036] The filamentous adhesive of the present invention comprises an adhesive and a core material having multiple filaments.

[0037] Here, "filamentous" refers to a shape that is sufficiently long in the long direction relative to the width direction, and in the 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. In addition, it can be bent in multiple directions and at multiple angles like a filament.

[0038] It should be noted that the cross-sectional shape refers to the shape of the cross-section obtained by cutting the object perpendicular to the direction of its long side. The minor axis is the shortest axis among the axes passing through the centroid of the cross-sectional shape. The major axis is the longest axis among the axes passing through the centroid of the cross-sectional shape. The ratio of major axis to minor axis is preferably 100 or less, more preferably 50 or less, further preferably 10 or less, particularly preferably 5 or less, and most preferably 3 or less.

[0039] The filamentous adhesive of the present invention can be bent in multiple directions and at multiple angles, thus it can be bent according to the shape of the bonding area and can cope with the diversity of the shape of the bonding area.

[0040] <Core material>

[0041] The filamentous adhesive of the present invention has a core material. The core material is preferably filamentous.

[0042] The core material consists of multiple filaments, obtained by twisting or plying these filaments together. If the core material is multifilament yarn, sufficient strength and stable physical properties can be achieved. As a result, a filamentous bonded body with low quality deviation, excellent strength, and excellent adhesion can be obtained.

[0043] From the viewpoint of adhesion, the number of filaments in the core material is preferably 2 or more, more preferably 20 or more, and particularly preferably 40 or more.

[0044] On the other hand, if the number of filaments increases while keeping the thickness (fineness) of the core material at the same level, each filament will become thinner (fineness will decrease). If each filament becomes too thin, it may lead to a decrease in the strength and operability of the core material. Therefore, the number of filaments is preferably 2,000 or less, more preferably 1,500 or less, and particularly preferably 1,000 or less.

[0045] There are no particular restrictions on the type of resin used in filaments; the appropriate resin should be selected based on the required strength, quality, hardness, and other properties. For example, materials containing thermoplastic polymers, thermosetting polymers, rubber, and other polymeric materials can be cited.

[0046] Specifically, the following polymer materials can be used: rayon, cuprammonium cellulose, acetate, Promix, nylon, aramid, vinylon, polyvinylidene chloride, polyvinyl chloride, acrylonitrile fibers, polyolefins (polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, etc.), polyester resins (polyethylene terephthalate, etc.), vinyl chloride resin, vinyl acetate resin, polyimide resin, polyamide resin, fluoropolymers, polyurethane, polyvinyl chloride fiber, polylactic acid, and other polymer materials; synthetic rubbers (natural rubber, polyurethane, etc.); foamed polyurethane, foamed polychloroprene rubber, and other foams. Among these, polyester resin is preferred, and polyethylene terephthalate is more preferred.

[0047] From the viewpoint of suppressing the inclusion of adhesive in the core material, 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.

[0048] The core material can be formulated with various additives as needed, including fillers (inorganic fillers, organic fillers, etc.), anti-aging agents, antioxidants, UV absorbers, antistatic agents, lubricants, plasticizers, and colorants (pigments, dyes, etc.). Known or commonly used surface treatments, such as corona discharge treatment, plasma treatment, and primer coating, can be applied to the core material's surface.

[0049] The shape of the core material is not particularly limited; it can be adjusted appropriately according to the required strength, quality, hardness, and other properties.

[0050] 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.

[0051] The core material can simply consist of multiple filaments, or it can be a combination of filaments and short fiber yarns, processed yarns, hollow yarns, etc. As 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.

[0052] There is no particular limitation on the thickness of the core material; it can be adjusted appropriately according to the intended use, using a filamentous adhesive.

[0053] Furthermore, the twist count of the core material is preferably 1 twist / m or more. If the twist count is 1 twist / m or more, the voids described later are easily formed, thereby improving the impact resistance of the filamentous adhesive. The twist count of the core material is more preferably 20 twists / m or more, and even more preferably 50 twists / m or more.

[0054] On the other hand, in order to allow the core material to deform sufficiently when bonding multiple articles together, and in order 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 100 twists / m or less.

[0055] Furthermore, when the core material is twisted, based on the same viewpoint as above, it is preferable to control the twist coefficient K, as expressed in the following formula (A). The twist coefficient K is an indicator used to discuss the effects of twisting (the effects on core material aggregation, deformability, adhesive adhesion, etc.) regardless of the thickness of the core material. That is, although the effect of the twist number on the core material varies depending on the thickness of the core material, if the twist coefficient K is the same, it indicates that the effect of twisting on the core material is of the same degree regardless of the thickness of the core material.

[0056] The twist coefficient K is preferably 0 or more, and more preferably greater than 0. On the other hand, if the twist coefficient K is 200 or less, the flexibility of the core material and even the filamentous adhesive is improved, and it becomes easier to attach to complex shapes and narrow parts 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.

[0057] [Mathematical Expression 1]

[0058]

[0059] In formula (A), K refers to the twist coefficient, T refers to the number of twists (twist / m), and D refers to the fineness (dtex).

[0060] 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 on 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.

[0061] <Adhesive>

[0062] The filamentous adhesive of the present invention has an adhesive. The adhesive coats the core material and is impregnated within the core material.

[0063] The adhesive preferably covers the entire circumference of the surface of the core material along its long side. The entire circumference of the core material's surface refers to the entire circumference of the core material, centered on the centerline along its long side, which is a full 360° circumference.

[0064] However, the end faces of the core material may or 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 sometimes be left uncovered by adhesive.

[0065] By coating the entire circumference of the long-side surface of the core material with adhesive, a filamentous adhesive 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.

[0066] 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. If the coverage rate of the core material is 50% or more, core material breakage can be prevented, resulting in a filamentous adhesive with excellent strength.

[0067] The core material coverage can be calculated using, for example, an X-ray CT scanner (Xradia 520Versa, Zeiss, tube voltage 60kV, tube current 83μA, pixel size 1.5μm / pixel). Specifically, 1601 consecutive transmission images were taken across the entire circumference of the filamentous adhesive from 0° to 360°. Based on the data obtained from 3D reconstruction of the images using image analysis software (ImageJ, AVIZO (Thermo Fisher Scientific)), the core material, adhesive, and air were identified through ternary quantization and noise removal. It should be noted that this identification was performed as follows: the brightness of air and adhesive were separately determined, and a first threshold was set using their median values; then, the brightness of adhesive and core material were separately determined, and a second threshold was set using their median values. Using the images obtained through ternary quantization, the area of ​​the core-air interface (interface 1) and the area of ​​the core-adhesive interface (interface 2) were calculated, and the coverage was determined using the following formula.

[0068] Coverage rate (%) = {Area of ​​interface 2 / (Area of ​​interface 1 + Area of ​​interface 2)} × 100

[0069] It should be noted that the interface 1 described above does not include the interface between the core material and the filamentous adhesive of the present invention, which contains voids. Furthermore, when the filament is a hollow filament, the interface 1 described above does not include the interface between the core material and the voids inside the filament.

[0070] Furthermore, the aforementioned interface 2 refers to the interface between the adhesive and air. Interface 2 does not include the interface between the adhesive and the voids present in the filamentous adhesive of the present invention. Additionally, when the filament is a hollow filament, interface 2 does not include the interface between the adhesive and the voids inside the filament.

[0071] Here, "adhesive impregnated in the core material" means that the adhesive is present between the multiple filaments in the core material. If the adhesive is impregnated in the core material, it ensures a tight bond between the adhesive and the core material, making them less prone to peeling off, and thus increasing the strength of the filamentous bond.

[0072] There are no particular limitations on the type of adhesive. 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.

[0073] Among these, considering adhesion, acrylic adhesives and rubber adhesives are preferred, with acrylic adhesives being more preferred. It should be noted that one type of adhesive can be used alone, or two or more types can be used in combination.

[0074] Acrylic adhesives are adhesives that use polymers as the main agent, with alkyl methacrylates such as ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, isooctyl acrylate, and isononyl acrylate as the main components, and with the addition of monomers such as acrylonitrile, vinyl acetate, styrene, methyl methacrylate, acrylic acid, maleic anhydride, vinylpyrrolidone, glycidyl methacrylate, dimethylaminoethyl methacrylate, hydroxyethyl acrylate, and acrylamide as the modification monomers as needed.

[0075] Rubber-based adhesives are adhesives that use rubber-based polymers such as 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, and silicone rubber as the main agent.

[0076] In addition, adhesives may appropriately contain tackifying resins such as rosin-based, terpene-based, styrene-based, aliphatic petroleum-based, aromatic petroleum-based, xylene-based, phenol-based, benzofuran-indene-based, and their hydrides, as well as crosslinking agents, viscosity modifiers (thickeners, 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 various other additives.

[0077] It should be noted that either solvent-based or water-dispersible adhesives can be used as the adhesive. Considering the ability to perform high-speed coating, environmental friendliness, and minimal impact of the solvent on the core material (swelling, dissolution), water-dispersible adhesives are preferred.

[0078] 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, multiple applications of adhesive must be made on the core material during the manufacturing process, or time will be wasted on drying the applied adhesive, 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.

[0079] 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.

[0080] <Characteristics of filamentous adhesives>

[0081] The filamentous adhesive of the present invention contains 1 to 55% by volume voids.

[0082] Here, the aforementioned gaps refer to the spaces between multiple filaments within the core material. Additionally, if the filaments are hollow, the aforementioned gaps do not include the internal spaces within the filaments.

[0083] The porosity (hereinafter sometimes referred to as "porosity of the filamentous adhesive") in the filamentous adhesive of the present invention is 1% by volume or more, that is, the adhesive is not impregnated without gaps between all the filaments in the core material, but rather in a state where there are gaps between some of the filaments. If the porosity of the filamentous adhesive is made to be 1% by volume or more as described above, the filamentous adhesive can deform and release stress when subjected to impact, thus improving the impact resistance of the filamentous adhesive. The porosity of the filamentous adhesive is preferably greater than 1% by volume, more preferably 3% by volume or more, and particularly preferably 5% by volume or more.

[0084] Furthermore, if the porosity of the filamentous adhesive is 55% by volume or less, the amount of adhesive impregnated into the core material will not decrease excessively, ensuring the adhesion between the adhesive and the core material and preventing delamination. The porosity of the filamentous adhesive is preferably 50% by volume or less, more preferably 47% by volume or less, further preferably 45% by volume or less, particularly preferably 30% by volume or less, and most preferably 20% by volume or less.

[0085] It should be noted that the porosity of the filamentous adhesive can be determined using the method described in the examples.

[0086] The filamentous adhesive of the present invention preferably satisfies the following formula (1).

[0087] a / b≥2 (1)

[0088] In equation (1), a refers to the length of the longest straight line that can be placed in the gap, and b refers to the length of the widest part of the cross section obtained by cutting the filamentous adhesive perpendicular to the long side direction.

[0089] If equation (1) is satisfied, the imbalance of voids in the filamentous adhesive can be reduced, thus improving the impact resistance of the filamentous adhesive. Furthermore, if equation (1) is satisfied, the friction between the filaments increases during impact, and the impact energy is converted into heat energy, thus improving the impact resistance of the filamentous adhesive. The value of a / b is preferably 2 or more, more preferably 3 or more, and particularly preferably 5 or more.

[0090] It should be noted that the a / b value can be determined using the method described in the examples. The a / b value is the value for a filamentous adhesive with a length of 2.7 mm.

[0091] In addition, from the viewpoint of strength and operability, the thickness of the filamentous adhesive is preferably 50 to 2000 μm, more preferably 100 to 1000 μm.

[0092] [Method for manufacturing filamentous adhesives]

[0093] The method for manufacturing the filamentous adhesive of the present invention (hereinafter, sometimes referred to as "the manufacturing method of the present invention") includes a coating step of applying a coating liquid containing an adhesive onto a core material.

[0094] The coating solution is applied to the core material by means of impregnation, soaking, coating, etc., and then heated and dried as needed.

[0095] Heating and drying can be carried out at, for example, 80-90°C, preferably 100-110°C, for example, for 3-4 minutes, preferably 5-6 minutes.

[0096] The coating liquid can be applied using common coating machines such as gravure roller coating machines, reverse roller coating machines, kiss roller coating machines, dip roller coating machines, bar coating machines, doctor blade coating machines, and spray coating machines.

[0097] The manufacturing method of the present invention does not include a fiber-opening process. Because the fiber-opening process is omitted, the porosity of the filamentous adhesive of the present invention can be within the aforementioned range.

[0098] Furthermore, in the manufacturing method of the present invention, it is preferable to use a roller in the coating process, and the rotation speed of the roller is 0.3 to 5.0 times the core material extraction speed. By keeping the rotation speed of the roller within the above range, core material fiber breakage can be suppressed, thereby making it easier to keep the porosity of the filamentous adhesive of the present invention within the above range.

[0099] The rotational speed of the roller is more preferably 0.4 to 4.0 times the core material extraction speed, even more preferably 0.5 to 3.0 times, and particularly preferably 0.8 to 1.5 times.

[0100] Furthermore, it is preferable to apply a tension of 6.0 mN / dtex or less to the core material during the coating process. By applying a tension of 6.0 mN / dtex or less to the core material, fiber breakage of the core material can be suppressed, thereby making it easier to keep the porosity of the filamentous adhesive of the present invention within the above-mentioned range.

[0101] 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.

[0102] Furthermore, from the viewpoint of preventing the core material from being exposed due to the coating liquid not being coated onto the core material, the viscosity (hereinafter, sometimes referred to as "viscosity α") of the coating liquid at a shear rate of 100 (1 / s) is preferably 0.03 Pa·s or more, more preferably 0.05 Pa·s or more, and even more preferably 0.07 Pa·s or more.

[0103] From the viewpoint of preventing the coating liquid from not flowing, the coating liquid from not being applied to the core material, resulting in mottled or uneven coating, rough coating surface and exposed core material, the viscosity α is preferably 6 Pa·s or less, more preferably 5 Pa·s or less, and even more preferably 4 Pa·s or less.

[0104] It should be noted that the predicted viscosity α is close to the viscosity of the coating solution at the time of application.

[0105] From the viewpoint of preventing incompatibility of the coating liquid and exposure of the core material during the coating to drying process, the viscosity (hereinafter, sometimes referred to as "viscosity β") of the coating liquid at a shear rate of 0.1 (1 / s) is preferably 2 Pa·s or more, more preferably 4 Pa·s or more, and even more preferably 6 Pa·s or more.

[0106] From the viewpoint of leveling, the viscosity β is preferably 140 Pa·s or less, more preferably 120 Pa·s or less, and even more preferably 100 Pa·s or less.

[0107] It should be noted that viscosity β indicates the degree of fluidity of the coating liquid from application to drying.

[0108] Viscosities α and β can be determined using the methods described in the examples.

[0109] Example

[0110] The present invention will be described in more detail below with examples, but the present invention is not limited to any of the examples below.

[0111] <Example 1>

[0112] (Preparation of coating solution 1)

[0113] 40 parts by mass of deionized water were added to a reaction vessel equipped with a condenser, nitrogen inlet pipe, thermometer, and stirrer. Nitrogen was introduced while stirring at 60°C for at least 1 hour to perform nitrogen replacement. 0.1 parts by mass of 2,2'-azobis[N-(2-carboxyethyl)-2-methylpropanediamine]n hydrate (polymerization initiator) were added to the reaction vessel. While maintaining the system at 60°C, monomer emulsion A was slowly added dropwise over 4 hours to initiate an emulsion polymerization reaction.

[0114] As monomeric emulsion A, an emulsion was obtained by adding 98 parts by weight of 2-ethylhexyl acrylate, 1.25 parts by weight of acrylic acid, 0.75 parts by weight of methacrylic acid, 0.05 parts by weight of lauryl mercaptan (chain transfer agent), 0.02 parts by weight of γ-methacryloyloxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Industry Co., Ltd., trade name "KBM-503") and 2 parts by weight of polyoxyethylene lauryl sulfate (emulsifier) ​​to 30 parts by weight of deionized water and emulsifying them.

[0115] After the addition of monomer emulsion A was completed, the system was kept at 60°C for 3 hours. After cooling the system to room temperature, the pH was adjusted to 7 by adding 10% ammonia to obtain an acrylic polymer emulsion (water-dispersible acrylic polymer).

[0116] Relative to 100 parts by mass of acrylic polymer contained in the aforementioned acrylic polymer emulsion, 24 parts by mass of tackifying resin emulsion (manufactured by Arakawa Chemical Industry Co., Ltd., trade name "E-865NT") based on solid content was added. Ion-exchanged water was further added to adjust the solid content concentration to 50% by mass, resulting in coating solution 1.

[0117] (Manufacturing of filamentous adhesives)

[0118] As the core material, a multifilament yarn is prepared by twisting a polyester fiber with a fineness of 165 dtex and a filament number of 48 into a twisting pattern of 200 times per meter.

[0119] The viscosity of coating liquid 1 was set to the viscosity listed in Table 1. The core material was then immersed in the liquid and coated using a coating roller rotating at the same speed as the extraction speed. At this time, the tension listed in Table 1 was applied to the core material. The material was then dried at 100°C for 4 minutes to obtain a filamentous adhesive with a diameter (width in the short side direction) of 160 μm and a porosity of 10%.

[0120] <Example 2>

[0121] The conditions of the core material used and the tension applied to the core material were as described in Table 1. Otherwise, the same procedure as in Example 1 was followed to obtain a filamentous adhesive with a diameter (width in the short side direction) of 450 μm and a porosity of 15%.

[0122] <Example 3>

[0123] The conditions of the core material used and the tension applied to the core material were as described in Table 1. Otherwise, the same procedure as in Example 1 was followed to obtain a filamentous adhesive with a diameter (width in the short side direction) of 200 μm and a porosity of 5%.

[0124] <Example 4>

[0125] The conditions of the core material used and the tension applied to the core material were as described in Table 1. Otherwise, the same procedure as in Example 1 was followed to obtain a filamentous adhesive with a diameter (width in the short side direction) of 450 μm and a porosity of 14%.

[0126] <Example 5>

[0127] The conditions of the core material used and the tension applied to the core material were as described in Table 1. Otherwise, the same procedure as in Example 1 was followed to obtain a filamentous adhesive with a diameter (width in the short side direction) of 450 μm and a porosity of 14%.

[0128] <Example 6>

[0129] The conditions of the core material used and the tension applied to the core material were as described in Table 1. Otherwise, the same procedure as in Example 1 was followed to obtain a filamentous adhesive with a diameter (width in the short side direction) of 450 μm and a porosity of 19%.

[0130] <Example 7>

[0131] The conditions of the core material used and the tension applied to the core material were as described in Table 1. Otherwise, the same procedure as in Example 1 was followed to obtain a filamentous adhesive with a diameter (width in the short side direction) of 450 μm and a porosity of 5%.

[0132] <Example 8>

[0133] Prepare the core material according to the conditions recorded in Table 1.

[0134] The core material is placed on a spacer with a paste thickness of 40 μm, and while transferring the adhesive obtained by drying the coating liquid 1 at 100°C for 4 minutes to the periphery of the core material, it is wound up to obtain a filamentous adhesive with a diameter (width in the short side direction) of 450 μm and a porosity of 19%.

[0135] <Example 9>

[0136] Prepare the core material according to the conditions recorded in Table 1.

[0137] The core material is placed on a spacer with a paste thickness of 20 μm, and while transferring the adhesive obtained by drying the coating liquid 1 at 100°C for 4 minutes to the periphery of the core material, it is wound up to obtain a filamentous adhesive with a diameter (width in the short side direction) of 450 μm and a porosity of 47%.

[0138] <Comparative Example 1>

[0139] Prepare the core material according to the conditions recorded in Table 1.

[0140] The solid component concentration and viscosity of coating liquid 1 were set to those specified in Table 1. The core material was then impregnated with the liquid and coated while the fiber was being opened. At this time, the tension specified in Table 1 was applied to the core material. After drying for 5 minutes, a filamentous adhesive with a diameter (width in the short side direction) of 200 μm was obtained.

[0141] <Comparative Example 2>

[0142] Prepare the core material according to the conditions recorded in Table 1.

[0143] The core material is placed on a spacer with a paste thickness of 10 μm, and while transferring the adhesive obtained by drying the coating liquid 1 at 100°C for 4 minutes to the periphery of the core material, it is wound up to obtain a filamentous adhesive with a diameter (width in the short side direction) of 450 μm.

[0144] <Comparative Example 3>

[0145] (Preparation of coating solution 2)

[0146] A reaction vessel equipped with a condenser, nitrogen inlet pipe, thermometer, dropping funnel, and stirring device was filled with 69 parts by mass of toluene and 163 parts by mass of ethyl acetate as solvents, and 80 parts by mass of butyl acrylate, 20 parts by mass of 2-ethylhexyl acrylate, 3 parts by mass of acrylic acid, 5 parts by mass of vinyl acetate, 0.1 parts by mass of 2-hydroxyethyl acrylate, and 0.2 parts by mass of 2,2-azobisisobutyronitrile as an initiator. Polymerization was carried out at 60°C for 6 hours in a nitrogen stream to obtain a solution of acrylic polymer.

[0147] Add 30 parts by mass of polymeric rosin ester resin relative to 100 parts by mass of polymeric components in the solution, and 1.5 parts by mass (based on solid content) of isocyanate-based crosslinking agent (manufactured by Nippon Polyurethane Industry Co., Ltd., trade name "CORONATE L") to the solution to obtain coating solution 2.

[0148] (Manufacturing of adhesive tape)

[0149] Using a coater, coating liquid 2 is applied to a silicone-treated release paper (release liner A) with a thickness of 135 μm, and dried at 110°C for 3 minutes to obtain an adhesive layer with a thickness of 50 μm.

[0150] On the adhesive layer, a black polyethylene foam substrate (manufactured by Sekisui Chemicals Co., Ltd., trade name "Volara XL-HN#03001W Black", thickness: 0.10 mm, foaming ratio: 2.9 cc / g) is bonded in contact with the adhesive layer to obtain a single-sided adhesive tape T with a layer structure of release liner A / adhesive layer / foam substrate.

[0151] Next, using a coater, the coating liquid 2 is applied to the release liner B and dried at 110°C for 3 minutes to obtain an adhesive layer with a thickness of 50 μm.

[0152] After attaching the single-sided adhesive tape T to the adhesive layer in a manner that makes contact with the foam substrate, the release liner B is peeled off to obtain a foamed double-sided adhesive tape with a layer structure of release liner A / adhesive layer / foam substrate / adhesive layer.

[0153] (Viscosity of the coating solution)

[0154] Regarding the viscosity of the coating solution, the viscosity was measured when the shear rate was changed from high speed (viscosity decreases) to low speed (viscosity recovers).

[0155] Specifically, a 1g sample (coating solution) was placed into a measuring plate (MP35 Steel, 18 / 8, sensor Rotor C35 / 1, cone with D = 35mm, 1° Titan, gap between plates 0.225mm). A viscoelasticity measuring device (rheometer trade name "RS-600", manufactured by HAAKE) was used. First, at 23°C, the solution viscosity (Pa·s) of the coating solution was measured at a shear rate of 0.01 (1 / s) for 10 seconds. Then, after 20 seconds, the shear rate was changed to 9000 (1 / s) (A), and after another 20 seconds, it was returned to a shear rate of 0.01 (1 / s) (B), and the solution viscosity (Pa·s) of the coating solution during this period was measured.

[0156] The viscosity (Pa·s) of the coating solution at a shear rate of 100 (1 / s) when the shear rate is changed to 9000 (1 / s) (A) is taken as the viscosity (Pa·s) of the coating solution at a shear rate of 100 (1 / s). Furthermore, the viscosity (Pa·s) of the coating solution at a shear rate of 0.1 (1 / s) when the shear rate is restored to 0.01 (1 / s) (B) is taken as the viscosity (Pa·s) of the coating solution at a shear rate of 0.1 (1 / s).

[0157] (Core material tension)

[0158] The tension of the core material was measured during coating using a digital force gauge (AD-4932A). Specifically, the tension between the core material extraction point and the coating roller was measured by reading the stress applied to the terminals of the force gauge.

[0159] (Porosity: Examples 1-9, Comparative Examples 1 and 2)

[0160] The porosity of the filamentous adhesive was calculated using an X-ray CT apparatus (Xradia 520Versa, Zeiss, tube voltage 60kV, tube current 83μA, pixel size 1.5μm / pixel).

[0161] Specifically, 1601 continuous transmission images were captured across the entire circumference of the filamentous adhesive from 0° to 360°. Using image analysis software (ImageJ, AVIZO (Thermo Fisher Scientific)) to perform 3D reconstruction on the images, ternary values ​​were performed based on brightness to identify the core material, adhesive, and air contained within the filamentous adhesive. This identification was performed as follows: the brightness of air and adhesive were separately determined, and their median values ​​were used to set a first threshold; then, the brightness of adhesive and core material were separately determined, and their median values ​​were used to set a second threshold. Using the ternary images, the volume ratios of the core material, air, and adhesive were calculated to obtain the porosity of the filamentous adhesive. The results are shown in Table 1.

[0162] It should be noted that when calculating the porosity, a 2cm sample was placed in an X-ray CT device, and a 2.7mm section was cut out along the fiber direction (long side direction) to calculate the porosity.

[0163] In addition, in Examples 1 to 9, X-ray CT equipment was used to confirm that the adhesive-coated core material and the adhesive impregnated in the core material were confirmed.

[0164] In addition, a cross-sectional photograph of the filamentous adhesive of Example 2 was obtained using an X-ray CT device. This cross-sectional photograph is illustrated in... Figure 1 .

[0165] (Porosity: Comparative Example 3)

[0166] The porosity of the foam substrate can be calculated using the following formula.

[0167] Expansion ratio = 1 / (1 - porosity)

[0168] With the adhesive layer thickness set to 50 μm (total adhesive layer thickness: 100 μm) and the foam substrate thickness set to 100 μm, the porosity of the foamed double-sided adhesive tape was calculated. The results are shown in Table 1.

[0169] (the value of a / b)

[0170] The length of a: the longest straight line that can be placed in the gap, and b: the length of the widest part in the cross-section obtained by cutting the filamentous adhesive perpendicular to the long side direction, are measured using the X-ray CT device described above.

[0171] Specifically, 1601 consecutive transmission images were captured across the entire circumference of the filamentous adhesive, from 0° to 360°. Using image analysis software (ImageJ, AVIZO (Thermo Fisher Scientific)) to perform 3D reconstruction on the images, ternary values ​​were performed based on brightness to identify the core material, adhesive, and air contained within the filamentous adhesive. This identification was performed as follows: the brightness of air and adhesive were separately determined, and their median values ​​were used to set a first threshold; then, the brightness of adhesive and core material were separately determined, and their median values ​​were used to set a second threshold. The a / b value was calculated using the ternary images. The results are shown in Table 1.

[0172] It should be noted that when calculating the value of a / b, a 2cm sample was placed in an X-ray CT device, and a 2.7mm section was cut out along the fiber direction (long side direction) to calculate the value of a / b.

[0173] (Evaluation of impact resistance)

[0174] The impact resistance of filamentous adhesives or foamed double-sided adhesive tapes is evaluated using the following methods.

[0175] First, prepare the first and second components as shown below.

[0176] Component 1: A square acrylic sheet with each side measuring 70mm and a thickness of 3mm.

[0177] Component 2: A rectangular polycarbonate resin board with a short side of 80mm, a long side of 110mm, and a thickness of 10mm, featuring a rectangular slit in the center (30mm on the short side and 40mm on the long side).

[0178] Next, attach the filamentous adhesive or foamed double-sided adhesive tape to the first component in a 50×60mm rectangle along all four sides. Then, attach the first and second components together, aligning the center of the first component with the center of the slit in the second component, and press them together at 0.3MPa for 20 seconds to obtain the joint. A schematic diagram of the joint is shown below. Figure 2 .

[0179] Then, towards Figure 2Following the directions of arrows 21-26, drop the joint from a height of 5cm onto the iron plate in the order of arrows 21-26. Treat this as one group. If the two components are not separated at the end of the third group (a total of 18 drops), gradually increase the height. Starting from 5cm, increase the height sequentially to 15cm, 30cm, 60cm, and 90cm, repeating the same operation. Record the number of drops at the points where the two components separate in Table 1.

[0180] (Evaluation of reoperability)

[0181] Prepare a square acrylic sheet (70mm on each side, 3mm thick) and 5cm of adhesive tape or foam double-sided adhesive strips. Attach the adhesive tape or foam double-sided adhesive strips to the acrylic sheet so that 1cm of the strips protrude from the sheet.

[0182] Then, an acrylic sheet of the same shape was placed on the filamentous adhesive or foamed double-sided adhesive tape, and pressed at 0.3 MPa for 20 seconds to obtain a bond. The protruding filamentous adhesive or foamed double-sided adhesive tape was stretched in a direction perpendicular to the long side of the filamentous adhesive or foamed double-sided adhesive tape, and evaluated according to the following evaluation criteria. The results are shown in Table 1.

[0183] 〇: Able to extract filamentous adhesive or foamed double-sided adhesive tape without damaging the core material or substrate.

[0184] ×: The core material or substrate is damaged when the filamentous adhesive or foamed double-sided adhesive tape is pulled out, or the filamentous adhesive or foamed double-sided adhesive tape cannot be pulled out.

[0185] [Table 1]

[0186]

[0187] According to Table 1, when comparing Examples 1 and 3 and Comparative Example 1 with similar diameters, it can be seen that the filamentous adhesive of Example 1 has higher impact resistance.

[0188] Similarly, when comparing Examples 2, 4-9 and Comparative Example 2 with the same diameter, it can be seen that the filamentous adhesives of Examples 2, 4-9 have higher impact resistance.

[0189] Furthermore, it can be seen that Comparative Example 3 has low impact resistance and poor reworkability.

[0190] The present invention has been described in detail and with reference to specific embodiments, but 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. This application is based on Japanese Patent Application No. 2020-165590, filed on September 30, 2020, the contents of which are incorporated herein by reference.

[0191] Explanation of reference numerals in the attached figures

[0192] 11. Component 1

[0193] 12 Component 2

[0194] 13. Joint

[0195] 21 arrows

[0196] 22 arrows

[0197] 23 arrows

[0198] 24 arrows

[0199] 25 arrows

[0200] 26 arrows

Claims

1. A method for manufacturing a filamentous adhesive, comprising an adhesive and a core material having multiple filaments, wherein, This includes a coating process of applying a coating liquid containing the adhesive onto the core material. Excluding the fiber opening process, In the coating process, a roller is used, and the rotational speed of the roller is 0.3 to 5.0 times the extraction speed of the core material. In the coating process, a tension of less than 6.0 mN / dtex is applied to the core material. The core material has a twist count of 1~500 twists / m. The viscosity of the coating liquid at a shear rate of 100 (1 / s) is 0.03~6 Pa·s. The viscosity of the coating liquid is 2~140 Pa·s under a shear rate of 0.1 (1 / s). The filamentous adhesive satisfies the following formula (1): a / b≥2 (1) In equation (1), a refers to the length of the longest straight line that can be placed in the gap, and b refers to the length of the widest part of the cross section obtained by cutting the filamentous adhesive perpendicular to the long side direction.

2. The method for producing a filamentous adhesive body according to claim 1, wherein The filamentous adhesive is a filamentous adhesive containing an adhesive and a core material having multiple long filaments. The adhesive coats the core material and is impregnated within the core material. The filamentous adhesive contains 1 to 55% by volume voids.

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