Adhesive tape and its uses

Abstract

To provide an adhesive tape that has all of easy deformability in a low temperature range, good flexibility in a room temperature range, and deformation resistance in a high temperature range in a balanced manner.SOLUTION: Provided is an adhesive tape comprising: a base material layer comprising a polyvinyl chloride-based film; and an adhesive layer arranged on at least one surface of the base material layer. The base material layer comprises polyvinyl chloride, a plasticizer and an elastomer. The elastomer comprises at least one component selected from a thermoplastic polyurethane and a thermoplastic polyester elastomer.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an adhesive tape comprising a polyvinyl chloride (PVC) film, and a wire harness using the adhesive tape. [Background technology]

[0002] Adhesive tapes in which an adhesive layer is disposed on at least one surface of a PVC film (hereinafter also referred to as "PVC adhesive tapes") are widely used for various applications such as electrical insulation, packaging, and protection due to their ease of use. Patent documents 1 to 3 are examples of prior art documents relating to PVC adhesive tapes. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] International Publication No. 2019 / 069577 [Patent Document 2] International Publication No. 2018 / 225541 [Patent Document 3] International Publication No. 2019 / 049565 [Overview of the project] [Problems that the invention aims to solve]

[0004] The above-mentioned PVC adhesive tape is preferably used as a wire bundling tape in wire harnesses consisting of numerous wires routed in automobiles, aircraft, etc. (hereinafter also referred to as automobiles, etc.). For such applications, PVC adhesive tape is required to exhibit good flexibility suitable for the wrapping work at room temperature, which is the ambient temperature at which the wrapping work is generally performed. In addition, wire harnesses may be deeply bent during the assembly process due to space constraints, and may be subjected to bending deformation due to vibrations and shocks associated with the operation of automobiles, etc., even after assembly. Furthermore, depending on the routing path, wire harnesses may interfere with the body or other parts. Wire harnesses used in automobiles, etc., may be exposed to a wide temperature range, sometimes to temperatures below -30°C, while also being heated by heat from power sources or sunlight. Therefore, a PVC adhesive tape is desirable that exhibits easy deformability, which prevents cracking and whitening even when the wire harness is bent at low temperatures, and that exhibits little deformation or denting due to loads and stresses at high temperatures (good deformation resistance). The cracking and whitening at low temperatures, and the deformation and denting at high temperatures mentioned above, can be factors that reduce the protective performance of PVC adhesive tape.

[0005] However, achieving a good balance between the ease of deformation at low temperatures, good flexibility at room temperature, and deformation resistance at high temperatures in PVC adhesive tape is not easy. For example, generally, increasing the plasticizer content in PVC film improves flexibility at room temperature, but tends to impair deformation resistance at high temperatures.

[0006] Therefore, the present invention aims to provide an adhesive tape having a structure in which an adhesive layer is disposed on at least one surface of a base layer made of a polyvinyl chloride film, which achieves a good balance between easy deformation at low temperatures, good flexibility at room temperature, and deformation resistance at high temperatures. Another related objective is to provide a wire harness using such an adhesive tape. [Means for solving the problem]

[0007] According to this specification, an adhesive tape is provided that includes a base material layer made of a polyvinyl chloride-based film and an adhesive layer disposed on at least one surface of the base material layer. In this adhesive tape, the base material layer includes polyvinyl chloride, a plasticizer, and an elastomer. Here, the elastomer includes at least one of thermoplastic polyurethane (TPU) and thermoplastic polyester elastomer (TPEE). According to the adhesive tape having the above configuration, it is possible to achieve a good balance between easy deformability in a low temperature range, good flexibility in a room temperature range, and deformation resistance in a high temperature range. Such an adhesive tape is suitable, for example, as an adhesive tape used for protecting and bundling electric wires of a wire harness.

[0008] In some preferred embodiments, the content of the elastomer in the base material layer is 3.0% by mass or more and 30% by mass or less. According to the adhesive tape provided with a base material layer satisfying the elastomer content, the effects of the technology disclosed herein can be preferably realized.

[0009] The base material layer of the adhesive tape disclosed herein preferably includes at least TPU as the elastomer. According to the adhesive tape provided with a PVC film containing TPU as the base material layer, the effects of the technology disclosed herein can be preferably realized.

[0010] In some embodiments where the base material layer includes TPU, the urethane bond fraction of the TPU can be, for example, 10 mol% or more and 20 mol% or less. The technology disclosed herein can be preferably implemented using TPU having a urethane bond fraction within the above range.

[0011] In some embodiments, as the elastomer, those satisfying at least one of a durometer hardness of A75 or more and A95 or less and D25 or more and D45 or less are suitable. According to a base material layer including an elastomer satisfying such a durometer hardness, an adhesive tape with a good balance of characteristics in a low temperature range, a room temperature range, and a high temperature range is easily obtained.

[0012] In some preferred embodiments, the content of the plasticizer in the base material layer is 15% by mass or more and 30% by mass or less. In the adhesive tape provided with the base material layer satisfying the plasticizer content, the effects of the technology disclosed herein can be preferably realized.

[0013] In some embodiments, the ratio of the content of the elastomer to the content of the plasticizer in the base material layer is preferably 0.1 or more and 1.5 or less on a mass basis. By combining and using the plasticizer and the elastomer in such a content ratio, the effects of the technology disclosed herein can be preferably realized.

[0014] Further, according to this specification, a wire harness is provided in which any of the adhesive tapes disclosed herein has a configuration wound around an electric wire. The wire harness having the above configuration is less likely to cause cracks or whitening of the base material layer even when bent and deformed at low temperature, and has less deformation or indentation of the base material layer even when subjected to load or stress at high temperature, so that it can be a good protector for the above electric wire.

Brief Description of Drawings

[0015] [Figure 1] It is a cross-sectional view schematically showing the configuration of an adhesive tape according to an embodiment. [Figure 2] It is a schematic explanatory view of a low-temperature bending test. [Figure 3] It is a schematic explanatory view of room-temperature bending rigidity measurement. [Figure 4] It is a schematic explanatory view of measurement of heat deformation amount.

Modes for Carrying Out the Invention

[0016] Hereinafter, preferred embodiments of the present invention will be described. Matters other than those specifically mentioned in this specification and necessary for the implementation of the present invention can be understood by those skilled in the art based on the teachings regarding the implementation of the invention described in this specification and the common technical knowledge at the time of filing. The present invention can be implemented based on the content disclosed in this specification and the common technical knowledge in the relevant field.

[0017] <Example of adhesive tape composition> The adhesive tape disclosed herein comprises a base layer made of a polyvinyl chloride film and an adhesive layer disposed on at least one surface of the base layer. The adhesive tape may be in the form of a single-sided adhesive tape with a base material having an adhesive layer on one side of the base material (supporting base material), or it may be a double-sided adhesive tape with a base material having adhesive layers on both sides of the base material. The adhesive tape disclosed herein may be in the form of a roll or a sheet. Furthermore, the adhesive tape may have slits at the ends to improve the ease of cutting the tape during tape winding operations.

[0018] Figure 1 shows an example of the configuration of the adhesive tape disclosed herein. The PVC adhesive tape 1 shown in Figure 1 is configured as a single-sided adhesive tape comprising a base layer (e.g., a single-layer PVC film) 11 having a first surface 11A and a second surface 11B, and an adhesive layer 21 disposed on the first surface 11A. Before use (i.e., before being attached to an object), the adhesive tape 1 may be in the form of an adhesive tape roll in which the adhesive layer 21 comes into contact with the second surface 11B of the base layer 11 by winding it in the longitudinal direction, as shown in Figure 1, thereby protecting its surface (adhesive surface) 21A. Alternatively, the surface 21A of the adhesive layer 21 may be protected by a release liner, the side facing the adhesive layer 21 being a release surface. Known or conventional release liners can be used without particular limitation. For example, release liners having a release treatment layer on the surface of a base material such as a plastic film or paper, or release liners made of low-adhesion materials such as fluoropolymers (polytetrafluoroethylene, etc.) or polyolefin resins (polyethylene, polypropylene, etc.) can be used.

[0019] <Base material layer> The substrate layer disclosed herein consists of a PVC film. The PVC film is typically obtained by filming a PVC composition containing predetermined components using a known method. Here, the PVC composition refers to a composition in which the main component of the resin components, i.e., the component present in more than 50% by mass, is PVC. According to such a PVC composition, a PVC film (typically a film made of flexible PVC resin) exhibiting suitable physical properties as a substrate for adhesive tape can be formed. The proportion of PVC in the resin components contained in the above PVC composition is preferably 55% by mass or more, more preferably 65% ​​by mass or more, and may also be 75% by mass or more, 80% by mass or more, 85% by mass or more, or 90% by mass or more. Furthermore, the proportion of PVC in the resin components contained in the above PVC composition may be, for example, 99% by mass or less. From the viewpoint of making it easier to exert the effects of including the elastomer, in some embodiments, the proportion of PVC is suitable to be 98% by mass or less, preferably 96% by mass or less, more preferably 94% by mass or less, may also be 90% by mass or less, may also be 85% by mass or less, or may be 80% by mass or less.

[0020] (PVC) The PVC constituting the above PVC composition may be various polymers in which vinyl chloride is the main monomer (the main component among the monomer components, i.e., the monomer accounting for more than 50% by mass). In other words, the concept of PVC as used herein includes not only homopolymers of vinyl chloride but also copolymers of vinyl chloride with various comonomers. Examples of the above comonomers include vinylidene chloride; olefins such as ethylene and propylene (preferably olefins having 2 to 4 carbon atoms); carboxyl group-containing monomers or acid anhydrides such as acrylic acid, methacrylic acid (hereinafter, acrylic and methacrylic are collectively referred to as "(meth)acrylic"), maleic acid, and fumaric acid (maleic anhydride, etc.); (meth)acrylic acid esters, for example, esters of (meth)acrylic acid with an alcohol alkyl or cycloalkyl alcohol having about 1 to 10 carbon atoms; vinyl ester monomers such as vinyl acetate and vinyl propionate; styrene monomers such as styrene, substituted styrene (α-methylstyrene, etc.), and vinyltoluene; acrylonitrile; and the like. As the above copolymer, it is preferable that the copolymerization ratio of vinyl chloride is 70% by mass or more (more preferably 90% by mass or more). PVC can be obtained by polymerizing such monomers using a suitable method (typically suspension polymerization).

[0021] While not particularly limited, the average degree of polymerization of the PVC contained in the PVC composition may be approximately 800 to 1800. Considering the balance between processability (moldability) and strength, a PVC composition with an average degree of polymerization in the range of approximately 1000 to 1500 is preferred.

[0022] The PVC content in the substrate layer is typically 30% by mass or more, and may be 35% by mass or more. From the viewpoint of suitably exhibiting the effects of PVC, a PVC content of 40% by mass or more (e.g., more than 40% by mass) is appropriate, preferably 45% by mass or more, more preferably 48% by mass or more, and may also be 50% by mass or more (e.g., more than 50% by mass), 52% by mass or more, 55% by mass or more, or 57% by mass or more. Furthermore, the proportion of PVC in the substrate layer is, for example, approximately 80% by mass or less, and from the viewpoint of more effectively exhibiting the effects of plasticizers and elastomers contained in the substrate, it is preferably 75% by mass or less, more preferably 70% by mass or less, and may be, for example, 65% by mass or less.

[0023] (Plasticizer) The substrate layer disclosed herein contains a plasticizer. By using a combination of a plasticizer and an elastomer, it is possible to preferably realize an adhesive tape that balances easy deformation at low temperatures, good flexibility at room temperature, and deformation resistance at high temperatures. As the plasticizer, various materials known to exhibit a plasticizing effect on PVC (for example, a plasticizing effect at least at room temperature (typically 23°C)) can be used without particular limitation. Examples of the above plasticizers include aromatic carboxylic acid esters such as benzoic acid esters (glycol benzoate, etc.), phthalic acid esters, terephthalic acid esters (di-2-ethylhexyl terephthalate, etc.), trimellitic acid esters, and pyromellitic acid esters; aliphatic carboxylic acid esters such as adipic acid esters, sebacate acid esters, azelaic acid esters, maleic acid esters, and citrate esters (tributyl acetylcitrate, etc.); polyesters of polycarboxylic acids and polyhydric alcohols; and other examples include, but are not limited to, polyether polyesters, epoxy polyesters (epoxidized vegetable oils such as epoxidized soybean oil and epoxidized linseed oil, epoxidized fatty acid alkyl esters, etc.), and phosphate esters (tricresyl phosphate, etc.). The plasticizer can be used alone or in appropriate combinations of two or more types.

[0024] As the phthalate ester (phthalate ester plasticizer) mentioned above, for example, a diester of phthalic acid and an alkyl alcohol having 4 to 16 carbon atoms (preferably 6 to 14, typically 8 to 13) can be used, and preferred examples include di-n-octyl phthalate, di-2-ethylhexyl phthalate, diisononyl phthalate, and diisodecyl phthalate.

[0025] As the trimellitic acid ester (trimellitic acid ester-based plasticizer) mentioned above, for example, triesters of trimellitic acid and an alkyl alcohol having 6 to 14 carbon atoms (typically 8 to 12 carbon atoms) can be used, and preferred examples include tri-n-octyl trimellitic acid, tri-2-ethylhexyl trimellitic acid, triisononyl trimellitic acid, tri-n-decyl trimellitic acid, and triisodecyl trimellitic acid.

[0026] As the pyromellitic acid ester (pyromellitic acid ester-based plasticizer) mentioned above, for example, a tetraester of pyromellitic acid and an alkyl alcohol having 6 to 14 carbon atoms (typically 8 to 12) can be used, and preferred examples include tetra-n-octyl pyromellitic acid, tetra-2-ethylhexyl pyromellitic acid, and tri-n-decyl pyromellitic acid.

[0027] As the above-mentioned adipic acid ester (adipic acid ester-based plasticizer), for example, a diester of adipic acid and an alkyl alcohol having 4 to 16 carbon atoms (preferably 6 to 14, typically 8 to 13) can be used, and preferred examples include di-n-octyl adipate, di-2-ethylhexyl adipate, and diisononyl adipate.

[0028] As the above-mentioned polyester (polyester-based plasticizer), for example, polyester compounds obtained from polycarboxylic acids such as succinic acid, adipic acid, suberic acid, azelaic acid, sebacic acid, citric acid, phthalic acid, isophthalic acid, terephthalic acid, and trimellitic acid, and polyhydric alcohols such as (poly)ethylene glycol (here, "(poly)ethylene glycol" comprehensively refers to ethylene glycol and polyethylene glycol; the same applies hereinafter), (poly)propylene glycol, (poly)butylene glycol, (poly)hexanediol, (poly)neopentyl glycol, and polyvinyl alcohol can be used. As the above-mentioned polycarboxylic acid, aliphatic dicarboxylic acids having 4 to 12 carbon atoms (typically 6 to 10) are preferred, and adipic acid and sebacic acid are preferred examples. In particular, adipic acid is desirable in terms of versatility and cost. The polyhydric alcohols mentioned above are preferably aliphatic diols having 2 to 10 carbon atoms, and preferred examples include ethylene glycol and butylene glycol (e.g., 1,3-butanediol, 1,4-butanediol).

[0029] In some preferred embodiments, carboxylic acid esters are preferably used as plasticizers contained in the substrate layer. As the carboxylic acid ester, one or more aromatic carboxylic acid esters and aliphatic carboxylic acid esters as described above can be used individually or in combination of two or more.

[0030] The molecular weight of the plasticizer is not particularly limited. In some embodiments, a plasticizer with a molecular weight of less than 1500 (e.g., less than 1000) is used. The molecular weight of the above plasticizer is, for example, 250 or more, and may be 400 or more. The upper limit of the molecular weight of the above plasticizer is not particularly limited, and from the viewpoint of handling properties, a molecular weight of 800 or less (e.g., less than 600, and even less than 500) is preferably used. Among these, carboxylic acid esters having the above molecular weight are preferably used.

[0031] In some embodiments, the base layer may contain a polyester-based plasticizer. Such embodiments make it easier to obtain an adhesive tape that achieves a high level of balance between heat degradation resistance and other properties. In some preferred embodiments, the base layer contains a combination of a polyester-based plasticizer and a carboxylic acid ester. According to these embodiments, the intermolecular interaction between the polyester-based plasticizer and the carboxylic acid ester can suppress the volatilization of the carboxylic acid ester and its migration to the adhesive layer. This is preferable from the viewpoint of suppressing heat degradation of the base layer and suppressing changes in adhesive strength over time.

[0032] In embodiments in which the base layer contains a combination of a polyester-based plasticizer and a carboxylic acid ester, it is preferable to use a polyester-based plasticizer with a molecular weight of 1000 or more and a carboxylic acid ester with a molecular weight of less than 1000 in combination. As carboxylic acid esters (PLLs) with a molecular weight of less than 1000, one or more aromatic carboxylic acid esters and aliphatic carboxylic acid esters with a molecular weight of less than 1000 can be used individually or in combination of two or more. For example, phthalate esters (di-n-octyl phthalate, di-2-ethylhexyl phthalate, diisononyl phthalate, diisodecyl phthalate, etc.), adipic acid esters (di-n-octyl adipate, di-2-ethylhexyl adipate, diisononyl adipate, etc.), trimellitic acid esters (tri-n-octyl trimellitic acid, tri-2-ethylhexyl trimellitic acid, etc.), pyromellitic acid esters (tetra-n-octyl pyromellitic acid, tetra-2-ethylhexyl pyromellitic acid, tri-n-decyl pyromellitic acid, etc.), citrate esters, sebacate esters, azelaic acid esters, maleic acid esters, benzoic acid esters, etc. can be used.

[0033] Aromatic carboxylic acid esters can be preferably used as PLLs. Among these, ester compounds derived from three or more (typically three- or four-functional) aromatic carboxylic acids are preferred, with trimellitic acid esters and pyromellitic acid esters being specific examples. Such PLLs readily exhibit the effects of the intermolecular interactions described above and have good compatibility with PVC. They are also preferred because they tend to have lower volatility compared to ester compounds derived from monofunctional or bifunctional aromatic carboxylic acids.

[0034] The molecular weight of PLL is typically 250 or higher, preferably 400 or higher, and more preferably 500 or higher, from the viewpoint of heat degradation resistance and other factors. The technology disclosed herein can preferably be implemented using PLL with a molecular weight of 600 or higher (more preferably 650 or higher, e.g., 700 or higher). The upper limit of the molecular weight of PLL is not particularly limited as long as it is less than 1000. From the viewpoint of handling and other factors, PLL with a molecular weight of 950 or lower (e.g., 900 or lower) can usually be preferably used.

[0035] In PLLs, the number of carbon atoms in the ester residue is preferably 6 or more, and more preferably 8 or more. Such PLLs readily exhibit the effects of the intermolecular interactions described above. They are also preferable because volatility tends to decrease as the molecular weight increases. Furthermore, the longer molecular chain increases flexibility, making it easier to form a liquid state at room temperature and improving handling. There is no particular upper limit to the number of carbon atoms in the ester residue, but from the viewpoint of handling and compatibility with PVC, it is usually 16 or less, preferably 14 or less, and more preferably 12 or less (for example, 10 or less).

[0036] As a polyester plasticizer (PLH) with a molecular weight of 1000 or more, one or more of the above-mentioned polyester plasticizers with a molecular weight of 1000 or more can be used individually or in combination of two or more. From the viewpoint of plasticizing effect and flexibility at low temperatures, polyesters of aliphatic dicarboxylic acids having 4 to 12 (typically 6 to 10) carbon atoms and polyhydric alcohols are preferred. Among these, adipic acid-based polyester plasticizers obtained from a dicarboxylic acid mainly composed of adipic acid and aliphatic diols such as neopentyl glycol, propylene glycol, and ethylene glycol are preferred. Such adipic acid-based polyester plasticizers have rich intermolecular interactions with PLL and PVC, thereby exhibiting a desirable effect of suppressing the volatilization of the plasticizer.

[0037] Commercially available products that can be used as PLH in the technologies disclosed herein include, specifically, DIC Corporation's product names "W-230H", "W-1020EL", "W-1410EL", "W-2050", "W-2300", "W-2310", "W-2314", "W-2360", "W-360ELS", "W-4010", etc.; ADEKA Corporation's product names "P-300", "PN-250", "PN-400", "PN-650", "PN-1030", "PN-1430", etc.; and Kao Corporation's product name "HA-5", etc.

[0038] The molecular weight of PLH is preferably 1000 or more. From the viewpoint of easily achieving the desired effect, it is usually advantageous to use PLH with a molecular weight of 2000 or more (preferably 2500 or more, for example 3000 or more). The techniques disclosed herein can preferably be carried out in a manner using PLH with a molecular weight of 4000 or more (for example 5000 or more). There is no particular upper limit to the molecular weight of PLH, but it is usually appropriate to keep it below 100000. From the viewpoint of better exhibiting the plasticizing effect of PVC and easily achieving the flexibility required for PVC adhesive tape, the molecular weight of PLH is preferably below 50000, more preferably below 25000, and even more preferably below 10000.

[0039] In this specification, the "molecular weight" of a plasticizer refers to the molecular weight determined from its chemical formula. For plasticizers with a molecular weight of 1000 or more, it refers to the weight-average molecular weight based on standard polystyrene, determined by gel permeation chromatography (GPC).

[0040] In embodiments in which PLH and PLL are used in combination as plasticizers in the substrate layer, the ratio of the amount of PLH to the amount of PLL is not particularly limited. For example, the mass (W) of PLL contained in the substrate layer PLL The mass of PLH (W) relative to ) PLH ) ratio (W PLH / W PLL ) can be set to approximately 0.1 to 500. From the viewpoint of suitably exhibiting the effects of the combination, usually W PLH / W PLL It is advantageous to set it to 0.5 to 100, and preferably to 1 to 50. In some preferred embodiments, W PLH / W PLL The value can be between 1 and 25, more preferably between 1 and 15 (e.g., 1 to 10), and even more preferably between 1 and less than 7 (typically between 1 and less than 5, e.g., 2 to 4.5).

[0041] In the technologies disclosed herein, the content of plasticizers in the base layer (the total amount if two or more types are used) is not particularly limited and can be appropriately set to obtain the desired effect. In some embodiments, the content of plasticizers in the base layer can be selected from, for example, a range of 10% by mass or more and 40% by mass or less. From the viewpoint of flexibility from room temperature to low temperatures, the content of plasticizers in the base layer is advantageous to be 15% by mass or more, preferably 18% by mass or more, and may also be 20% by mass or more, or 22% by mass or more. Furthermore, the content of plasticizers in the base layer is advantageous to be less than 36% by mass, preferably 30% by mass or less (for example, less than 30% by mass), and may also be 28% by mass or less, 25% by mass or less, or 23% by mass or less. The above plasticizer content can preferably be applied to the base layer of adhesive tape used for protecting and bundling wires in wire harnesses.

[0042] The content of the plasticizer can also be determined by its relative relationship to the PVC in the base layer. The content of the plasticizer per 100 parts by mass of PVC (the total amount if two or more types are used) can be selected from, for example, a range of 25 parts by mass or more and 70 parts by mass or less. In some embodiments, from the viewpoint of flexibility from room temperature to low temperatures, the content of the plasticizer per 100 parts by mass of PVC is appropriate to be 30 parts by mass or more, preferably 35 parts by mass or more, and may also be 37 parts by mass or more, or 39 parts by mass or more. Furthermore, from the viewpoint of deformation resistance in the high-temperature range, the content of the plasticizer per 100 parts by mass of PVC is appropriate to be 55 parts by mass or less, advantageous to be 50 parts by mass or less (for example, less than 50 parts by mass), may also be 48 parts by mass or less, may be 46 parts by mass or less, or may be 45 parts by mass or less.

[0043] (Elastomer) The base layer in the technology disclosed herein further comprises an elastomer. A thermoplastic elastomer is preferably used as the elastomer. In particular, it is preferable that the elastomer comprises at least one of thermoplastic polyurethane (TPU) and thermoplastic polyester elastomer (TPEE). By incorporating at least one of TPU and TPEE into the base layer, it is possible to improve low-temperature properties (for example, suppress crack formation when the wire harness is bent) and increase flexibility in the room temperature range while maintaining or improving high-temperature properties (for example, the amount of heat deformation measured by the method described in the examples below).

[0044] Thermoplastic polyurethane (TPU) is a multiblock copolymer composed of hard segments and soft segments. Examples of TPU include polyester-based thermoplastic polyurethane, polyether-based thermoplastic polyurethane, and polycarbonate-based thermoplastic polyurethane. Among these, polyester-based thermoplastic polyurethane and polyether-based thermoplastic polyurethane are preferred. Thermoplastic polyurethane can be used individually or in combination of two or more types.

[0045] Thermoplastic polyurethanes are generally prepared using polyols and diisocyanates, and optionally with chain extenders. Examples of polyols include polyester polyols, polyether polyols, and polycarbonate polyols.

[0046] Examples of the above-mentioned polyester polyols include: aliphatic dicarboxylic acids, such as succinic acid, adipic acid, sebacic acid, azelaic acid, etc.; aromatic dicarboxylic acids, such as phthalic acid, terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, etc.; alicyclic dicarboxylic acids, such as hexahydrophthalic acid, hexahydroterephthalic acid, hexahydroisophthalic acid, etc.; polyester polyols obtained by dehydration condensation reactions of these acid esters or acid anhydrides with ethylene glycol, 1,3-propylene glycol, 1,2-propylene glycol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, neopentyl glycol, 1,3-octanediol, 1,9-nonanediol, etc., or mixtures thereof; polylactone diols obtained by ring-opening polymerization of lactone monomers such as ε-caprolactone; and the like.

[0047] Examples of the above-mentioned polyester ether polyols include aliphatic dicarboxylic acids, such as succinic acid, adipic acid, sebacic acid, and azelaic acid; aromatic dicarboxylic acids, such as phthalic acid, terephthalic acid, isophthalic acid, and naphthalenedicarboxylic acid; alicyclic dicarboxylic acids, such as hexahydrophthalic acid, hexahydroterephthalic acid, and hexahydroisophthalic acid; compounds obtained by dehydration condensation reactions of these acid esters or acid anhydrides with glycols such as diethylene glycol or propylene oxide adducts, or mixtures thereof; and so on.

[0048] Examples of the polycarbonate polyols mentioned above include polycarbonate polyols obtained by reacting one or more polyhydric alcohols such as ethylene glycol, 1,3-propylene glycol, 1,2-propylene glycol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, neopentyl glycol, 1,8-octanediol, 1,9-nonanediol, and diethylene glycol with diethylene carbonate, dimethyl carbonate, diethyl carbonate, etc. Another example is a copolymer of polycaprolactone polyol (PCL) and polyhexamethylene carbonate (PHL).

[0049] Examples of the above-mentioned polyether polyols include polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol, etc., obtained by polymerizing cyclic ethers such as ethylene oxide, propylene oxide, and tetrahydrofuran, respectively, and their copolyethers.

[0050] Examples of the above-mentioned diisocyanates include tolylene diisocyanate (TDI), 4,4'-diphenylmethane diisocyanate (MDI), 1,5-naphthylene diisocyanate (NDI), tolidine diisocyanate, 1,6-hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), xylylene diisocyanate (XDI), hydrogenated XDI, triisocyanate, tetramethylxylene diisocyanate (TMXDI), 1,6,11-undecane triisocyanate, 1,8-diisocyanate methyl octane, lysine ester triisocyanate, 1,3,6-hexamethylene triisocyanate, bicycloheptane triisocyanate, and dicyclohexylmethane diisocyanate (hydrogenated MDI; HMDI).

[0051] Low molecular weight polyols are used as the chain extenders used in the preparation of TPUs. Examples of these low molecular weight polyols include aliphatic polyols such as ethylene glycol, 1,3-propylene glycol, 1,2-propylene glycol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, neopentyl glycol, 1,8-octanediol, 1,9-nonanediol, diethylene glycol, 1,4-cyclohexanedimethanol, and glycerin, as well as aromatic glycols such as 1,4-dimethylolbenzene, bisphenol A, and ethylene oxide or propylene oxide adducts of bisphenol A.

[0052] Commercially available polyester-based thermoplastic polyurethanes include BASF's Elastran C series (C90A10, C80A10, etc.), Elastran S series, Elastran ET5 series, Elastran ET6 series; and Dainichi Seika Kogyo Co., Ltd.'s Rezamin P-4000 series, Rezamin P-4500 series. Commercially available polyether-based thermoplastic polyurethanes include BASF's Elastran 11 series (1180A10, etc.), Elastran ET3 series, Elastran ET8 series; and Dainichi Seika Kogyo Co., Ltd.'s Rezamin P-2000 series. Commercially available polycarbonate-based thermoplastic polyurethanes include DIC Bayer Polymer Co., Ltd.'s Pandex T-7890N.

[0053] Although not particularly limited, in some embodiments, as the thermoplastic polyurethane, those having a urethane bond fraction in the range of 5 mol% or more and 25 mol% or less (more preferably 10 mol% or more and 20 mol% or less) can be preferably employed. Since the urethane bond in the thermoplastic polyurethane corresponds to the hard segment, when the urethane bond fraction becomes lower, the thermoplastic polyurethane tends to be softer. By using a thermoplastic polyurethane having a urethane bond fraction within the above range, an adhesive tape with a good balance of properties in the low temperature range, room temperature range, and high temperature range can be preferably realized.

[0054] The urethane bond fraction of the thermoplastic polyurethane can be determined as follows. That is, after the thermoplastic polyurethane to be measured is decomposed into each constituent unit by hydrolysis using the supercritical state of methanol, the molar fraction of each constituent unit is calculated by GC-MS (gas chromatography-mass spectrometry), 1 1H NMR, 13 13C NMR (solvent: DMSO-d6). The urethane bond fraction [mol%] of the thermoplastic polyurethane is given by the following formula: Urethane bond fraction = amount of isocyanate / total amount of monomers; and is determined thereby.

[0055] The polyester-based thermoplastic elastomer is a multi-block copolymer composed of a hard segment and a soft segment. As the above hard segment, an aromatic polyester is suitable, and specific examples include polybutylene terephthalate, polybutylene naphthalate, and the like. These can be used alone or in combination of two or more.

[0056] As the above soft segment, an aliphatic polyether, an aliphatic polyester, a polycarbonate, etc. are suitable, and specific examples include poly(ε-caprolactone), polytetramethylene glycol, polyalkylene carbonate, and the like. These can be used alone or in combination of two or more. As such block copolymers, one or more copolymers selected from the group consisting of polyester-polyester copolymers, polyester-polyether copolymers, and polyester-polycarbonate copolymers are preferred.

[0057] Examples of commercially available polyester thermoplastic elastomers include the Hytrel series from Toray DuPont and the Perprene series from Toyobo Co., Ltd.

[0058] The elastomer contained in the substrate layer in the technology disclosed herein may include one or more elastomers other than TPU and TPEE (hereinafter also referred to as "other elastomers"). Examples of the above other elastomers include chlorinated polyethylene (CPE), ethylene-vinyl acetate copolymer, (meth)acrylic acid ester-butadiene-styrene copolymer (e.g., methyl methacrylate-butadiene-styrene copolymer), acrylonitrile-butadiene-styrene copolymer, acrylonitrile-butadiene copolymer (NBR), styrene-butadiene copolymer, styrene-butadiene-styrene copolymer, chlorosulfonated polyethylene (CSM), other synthetic rubbers (isoprene rubber, butadiene rubber, etc.), composites and modified products thereof, etc. From the viewpoint of favorably exhibiting the effects of TPU and TPEE, in some embodiments, the amount of the above-mentioned other elastomer used is appropriate to be less than 50% by mass of the total elastomer, preferably 30% by mass or less, more preferably 15% by mass or less, and may also be 10% by mass or less, or 5% by mass or less. The other elastomer may not be used at all. The technology disclosed herein can preferably be implemented in which the elastomer contained in the substrate layer consists only of one or more thermoplastic elastomers selected from the group consisting of TPU and TPEE.

[0059] In some embodiments, it is preferable that the elastomer used in the base layer has a durometer hardness of at least one of A75 to A95 and D25 to D45. A base layer containing such a durometer hardness makes it easier to obtain an adhesive tape with a good balance of properties in low temperature, room temperature, and high temperature ranges. Here, the durometer hardness of the elastomer is measured according to JIS K7311. If a nominal value is provided by the manufacturer, that nominal value may be used.

[0060] The elastomer content in the base layer is not particularly limited and can be appropriately set to obtain the desired effect. In some embodiments, the elastomer content in the base layer is suitable to be 1% by mass or more, preferably 2% by mass or more, more preferably 3% by mass or more, and may also be 4% by mass or more, 5% by mass or more, 7% by mass or more, 10% by mass or more, 15% by mass or more, or 20% by mass or more. Increasing the amount of elastomer used tends to better exhibit the effects of elastomer content (for example, the effect of improving low-temperature properties and reducing room-temperature bending stiffness while maintaining or reducing the amount of heat deformation). Also, in some embodiments, the elastomer content in the base layer is suitable to be less than 50% by mass from the viewpoint of compatibility with PVC, etc., and may be, for example, 40% by mass or less, 30% by mass or less, less than 20% by mass, less than 15% by mass, less than 10% by mass, or less than 8% by mass.

[0061] The elastomer content can also be determined by its relative relationship to the PVC in the base layer. The elastomer content (total amount if two or more types are used) per 100 parts by mass of PVC can be selected from, for example, a range of 1 part by mass or more and 100 parts by mass or less. From the viewpoint of enhancing the effect of elastomer content, in some embodiments, the elastomer content per 100 parts by mass of PVC may be 3 parts by mass or more, 7 parts by mass or more, 10 parts by mass or more, 15 parts by mass or more, or 20 parts by mass or more. Also, in some embodiments, from the viewpoint of compatibility with PVC, the elastomer content in the base layer is appropriate to be 75 parts by mass or less, preferably 60 parts by mass or less, may be 50 parts by mass or less, may be 40 parts by mass or less, may be 30 parts by mass or less, may be 25 parts by mass or less, may be 20 parts by mass or less, or may be 15 parts by mass or less.

[0062] While not particularly limited, the ratio of the elastomer content to the plasticizer content in the base layer may be, for example, 0.05 to 2.0 by mass, and preferably 0.1 to 1.5. By using the above plasticizer and elastomer in combination with such a content ratio, an adhesive tape that balances easy deformation at low temperatures, good flexibility at room temperature, and deformation resistance at high temperatures can be suitably produced.

[0063] (Fatty acid metal salts) In the technology disclosed herein, the base layer preferably contains a fatty acid metal salt in addition to PVC and a plasticizer. During processing of the PVC film or PVC adhesive tape, or in the environment in which the adhesive tape is used, the PVC contained in the PVC film may be exposed to physical energy such as heat, ultraviolet rays, or shear force, and may discolor or have its physical, mechanical, or electrical properties impaired due to chemical reactions caused by these factors. By including a fatty acid metal salt in the base layer, the fatty acid metal salt can function as a stabilizer that prevents or suppresses the above-mentioned chemical reactions.

[0064] As fatty acid metal salts, compounds that can function as stabilizers for PVC films can be used individually or in combination of two or more. For example, the fatty acids constituting the fatty acid metal group salt can be preferably selected from saturated or unsaturated fatty acids (which may be hydroxy fatty acids) with approximately 10 to 20 carbon atoms (typically 12 to 18), such as lauric acid, ricinoleic acid, and stearic acid. From the viewpoint of moldability and processability of the PVC film, metal stearic acid salts can be preferably used. Furthermore, from the viewpoint of suppressing changes over time in the PVC film or PVC adhesive tape and maintaining flexibility at low temperatures, metal laurate salts can be preferably used. In some preferred embodiments, metal stearic acid salts and metal laurate salts can be used in combination. In this case, the ratio of the amount of metal laurate salt used to the amount of metal stearic acid salt used is not particularly limited, but for example, it can be 0.1 to 10 by mass, and is usually appropriate to be 0.2 to 5 (e.g., 0.5 to 2).

[0065] Considering the growing awareness of environmental hygiene in recent years, metals other than lead (lead-free metals) are preferably used as the metal constituting the fatty acid metal salt. According to the technology disclosed herein, even in embodiments that do not use lead-containing stabilizers, PVC adhesive tapes exhibiting good properties can be realized. As the above metal, for example, a metal element belonging to any of groups 1, 2, 12, 13, and 14 of the periodic table (excluding Pb) can be selected, and preferred examples include Li, Na, Ca, Mg, Zn, Ba, and Sn. As the above fatty acid metal salt, Ca salts and Ba salts can be preferably adopted from the viewpoint of cost and availability. Furthermore, Zn salts can be preferably adopted from the viewpoint of moldability and processability of the PVC film. In some preferred embodiments, Ca salts and Zn salts can be used in combination. In this case, the ratio of the amount of Zn salt used to the amount of Ca salt used is not particularly limited, but for example, it can be 0.1 to 10 by mass, and it is usually appropriate to set it to 0.2 to 5 (e.g., 0.5 to 2). The technology disclosed herein can be preferably implemented, for example, in a manner in which calcium stearate and zinc laurate are present in the above-mentioned mass ratio, or in a manner in which zinc stearate and calcium laurate are present in the above-mentioned mass ratio. In applications where the use of fatty acid Pb salts is permitted, it is also possible to incorporate fatty acid Pb salts into the PVC film.

[0066] The amount of fatty acid metal salt used is not particularly limited. The fatty acid metal salt content in the base layer (total amount if two or more types are used) can be, for example, 0.01% by mass or more, preferably 0.05% by mass or more from the viewpoint of obtaining a higher effect, and more preferably 0.1% by mass or more. There is no particular upper limit on the amount of fatty acid metal salt used, but it is usually appropriate to have 10% by mass or less in the base layer, preferably 5% by mass or less from the viewpoint of flexibility at low temperatures, and may be 3% by mass or less, or even 1% by mass or less. Fatty acid metal salt may not be used at all.

[0067] (Antioxidant) In addition to PVC and plasticizers, the substrate layer in the technology disclosed herein may contain antioxidants. By including antioxidants in the substrate layer, a more durable PVC adhesive tape can be realized.

[0068] Any known material capable of exhibiting antioxidant function can be used as an antioxidant without particular limitations. Examples of antioxidants include phenolic antioxidants, phosphorus-based antioxidants, sulfur-based antioxidants, and amine-based antioxidants. Antioxidants can be used individually or in combination of two or more.

[0069] Suitable examples of antioxidants include phenolic antioxidants such as hindered phenolic antioxidants. Examples of hindered phenolic antioxidants include pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (trade name "Irganox1010", manufactured by Ciba Japan), octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate (trade name "Irganox1076", manufactured by Ciba Japan), 4,6-bis(dodecylthiomethyl)-o-cresol (trade name "Irganox1726", manufactured by Ciba Japan), and triethylene glycol-bis[3-(3-tert Examples include butyl-5-methyl-4-hydroxyphenyl)propionate (product name "Irganox245", manufactured by Ciba Japan), bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate (product name "TINUVIN770", manufactured by Ciba Japan), and a polycondensate of dimethyl succinate and 4-hydroxy-2,2,6,6-tetramethyl-1-piperidineethanol (dimethyl succinate-1-(2-hydroxyethyl)-4-hydroxy-2,2,6,6-tetramethylpiperidine polycondensate) (product name "TINUVIN622", manufactured by Ciba Japan). Among these, pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (trade name "Irganox1010", manufactured by Ciba Japan Co., Ltd.) and triethylene glycol-bis[3-(3-tert-butyl-5-methyl-4-hydroxyphenyl)propionate] (trade name "Irganox245", manufactured by Ciba Japan Co., Ltd.) are preferred.

[0070] The amount of antioxidant (total amount if two or more types are used) is not particularly limited, and for example, it can be 0.001% by mass or more in the base layer. From the viewpoint of obtaining a higher effect, it is usually appropriate to use 0.01% by mass or more of antioxidant in the base layer, preferably 0.05% by mass or more, and more preferably 0.1% by mass or more. There is no particular upper limit on the amount of antioxidant used, but it is usually appropriate to use 10% by mass or less.

[0071] (Filler) The substrate layer disclosed herein may contain one or more types of fillers as needed. Including fillers in the substrate layer is preferable from the viewpoint of improving the heat deformation resistance and abrasion resistance of the substrate layer (and consequently, the adhesive tape). Organic fillers, inorganic fillers, and organic-inorganic composite fillers can all be used as fillers. The fillers may have undergone known or conventional surface treatments. From the viewpoint of cost and availability, inorganic fillers are preferably used.

[0072] Examples of fillers include aluminum hydroxide, magnesium hydroxide, zirconium hydroxide, calcium hydroxide, potassium hydroxide, barium hydroxide, triphenylphosphate, ammonium polyphosphate, polyphosphate amide, ziriconium oxide, magnesium oxide, zinc oxide, titanium oxide, molybdenum oxide, guanidine phosphate, hydrotalcite, snaketite, zeolite, zinc borate, anhydrous zinc borate, zinc metaborate, barium metaborate, antimony oxide, antimony trioxide, antimony pentoxide, red phosphorus, talc, alumina, silica, boehmite, bentonite, sodium silicate, calcium silicate, calcium sulfate, calcium carbonate, magnesium carbonate, and carbon black. Among these, hydrotalcite, talc, alumina, silica, calcium silicate, calcium sulfate, calcium carbonate, and magnesium carbonate are preferred, with calcium carbonate being more preferred.

[0073] As surface-treated fillers, the various fillers listed above as specific examples may be used after surface treatment. For example, inorganic compounds surface-treated with a silane coupling agent may be preferred. As inorganic compounds, one or more known or conventional materials as inorganic flame retardants may be used. For example, inorganic compounds (e.g., magnesium hydroxide, aluminum hydroxide, basic magnesium carbonate, calcium carbonate, hydrotalcite) among those exemplified as specific examples of fillers above may be used.

[0074] Silane coupling agents used in surface treatment employ silane compounds having a structure in which a hydrolyzable silyl group, which has affinity or reactivity to inorganic materials, is chemically bonded to an organic functional group, which has affinity or reactivity to organic resins. Hydrolyzable groups bonded to silicon include alkoxy groups and acetoxy groups. Typical examples of alkoxy groups are methoxy and ethoxy groups. Examples of organic functional groups include amino groups, methacrylic groups, vinyl groups, epoxy groups, and mercapto groups. Specific examples of silane coupling agents include vinyltriethoxysilane, vinyl-tolyl(2-methoxyethoxy)silane, γ-methacryloxypropyltrimethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane, N-β-(aminoethyl)-γ-aminopropyltriethoxysilane, N-phenyl-γ-aminopropyltriethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, etc. These may be used individually or in combination of two or more.

[0075] The surface treatment method for inorganic compounds with silane coupling agents is not particularly limited and can be carried out by general methods, such as dry treatment or wet treatment. The amount of silane coupling agent adhering to the surface of the inorganic compound may vary depending on the type of coupling agent, the type of inorganic compound, and the specific surface area, and is not limited to a specific range, but is usually in the range of 0.1 to 5.0% by mass relative to the inorganic compound, and preferably in the range of 0.3 to 3.0% by mass.

[0076] The particle size of the filler and the inorganic compound to be surface-treated are not particularly limited, but are usually between 0.1 μm and 50 μm, and preferably between 0.5 and 20 μm. The above particle size is measured by laser diffraction.

[0077] In embodiments in which the substrate layer contains a filler, the filler content in the substrate layer is appropriately set within a range that does not impair the effects of the disclosed technology and is not limited to a specific range. The filler content in the substrate layer may be, for example, 1% by mass or more, 3% by mass or more, or 5% by mass or more. Furthermore, the upper limit of the filler content is usually appropriate to be 15% by mass or less, for example, 12% by mass or less, 10% by mass or less, or 8% by mass or less (for example, 6.5% by mass or less). The disclosed technology can also be implemented in embodiments that are substantially free of fillers.

[0078] Furthermore, the technology disclosed herein is preferably implemented in a manner in which the substrate layer contains at least one of hydrotalcite, talc, alumina, silica, calcium silicate, calcium sulfate, calcium carbonate, and magnesium carbonate (hereinafter also referred to as the "preferred inorganic filler group"; more preferably calcium carbonate) as a filler. In this embodiment, the content of fillers other than the preferred inorganic filler group in the substrate layer may be, for example, less than 100% by mass relative to 100% by mass of the preferred inorganic filler group. The content of fillers other than the preferred inorganic filler group may be approximately 50% by mass or less, 10% by mass or less, or 1% by mass or less, relative to 100% by mass of the preferred inorganic filler group. The technology disclosed herein can be implemented in a manner in which the substrate layer does not contain fillers other than the preferred inorganic filler group.

[0079] (Optional additives) The substrate layer in the technology disclosed herein may further contain, as necessary, known additives that can be used in PVC films (especially PVC films for PVC adhesive tapes), to the extent that the effects of the present invention are not significantly hindered. Examples of such additives include colorants such as pigments and dyes, stabilizers other than fatty acid metal salts (e.g., organotin compounds such as dioctyl syrup laurate), stabilizing agents (e.g., phosphates such as trialkyl phosphates and tetraalkyl(propane-2,2-diylbis(4,1-phenylene))bis(phosphite)), light stabilizers, ultraviolet absorbers, modifiers, flame retardants, antistatic agents, fungicides, lubricants, and the like.

[0080] In some preferred embodiments, the base layer has a content ratio of less than 15% by mass of components other than the polyvinyl chloride, plasticizer, and elastomer. This tends to favorably exhibit the effect of selecting the amount of plasticizer for PVC. The content ratio of the polyvinyl chloride and components other than the plasticizer in the base layer may be less than 12% by mass, less than 10% by mass, or less than 8% by mass. The lower limit of the content ratio of the polyvinyl chloride and components other than the plasticizer in the base layer is not particularly limited, but from the viewpoint of favorably exhibiting the effect of additive content, it is appropriate to be 1% by mass or more, but it may also be 3% by mass or more, or 5% by mass or more (for example, 7% by mass or more).

[0081] PVC films of such composition are typically obtained by molding a PVC composition having the corresponding composition into a film shape using methods known in the field of thermoplastic resin films. Such known molding methods include, for example, melt extrusion (inflation method, T-die method, etc.), melt flow method, and calendering method. The techniques disclosed herein can also be preferably implemented in embodiments where the PVC film has not been subjected to treatments that intentionally enhance the overall crosslinkability of the PVC film, such as the addition of a crosslinking agent (e.g., polyfunctional monomers such as trimethylolpropane trimethacrylate) or irradiation with active energy rays (e.g., electron beams). Such PVC films tend to yield highly flexible PVC adhesive tapes that can maintain the functions and performance required for adhesive tapes (e.g., end peelability and flexibility).

[0082] As an example, the following outlines a typical film preparation procedure using the calendering method. (1) Weighing: Weigh the PVC, plasticizer, and other materials used as needed, according to the target composition. (2) Mixing: Stir and mix each of the measured materials to prepare a homogeneous mixture (typically a powdery mixture, i.e., mixed powder). (3) Mixing: The mixture prepared in (2) above is heated to melt and mixed using two or more mixing rolls (typically metal rolls). The temperature of the mixing rolls should be set to, for example, 100°C to 250°C (preferably 150°C to 200°C). (4) Calendering: The mixture obtained in (3) above is put into a calendering machine to form a PVC film of any thickness.

[0083] In the adhesive tapes disclosed herein, the base layer is typically a single-layer or multi-layer support base made of PVC film. The adhesive tape may also be composed of other layers in addition to the base layer made of PVC film. In some embodiments, the other layer may be an auxiliary layer such as a printing layer, a release layer, or a primer layer provided on the surface of the PVC film. In some preferred embodiments, an adhesive layer is disposed on one side of a base layer made of a single layer of PVC film. Such an adhesive tape may have a configuration in which the adhesive layer is directly disposed on the base layer made of PVC film, and there may be no auxiliary layers such as the printing layer, release layer, or primer layer between the base layer and the adhesive layer.

[0084] In the adhesive tape disclosed herein, the thickness of the base layer is typically 500 μm or less, preferably 450 μm or less, and may also be 400 μm or less (e.g., less than 400 μm), less than 350 μm, less than 300 μm, less than 250 μm, or less than 220 μm. A base layer thickness that is not excessive is preferable from the viewpoint of ease of wrapping the adhesive tape around wires, etc., and is also advantageous from the viewpoint of preventing peeling of the ends after wrapping. Weight reduction can also be achieved by limiting the thickness of the base layer. In some embodiments, the thickness of the base layer is less than 200 μm, for example, less than 190 μm. Furthermore, the thickness of the base layer is, for example, 30 μm or more, preferably 55 μm or more, and more preferably 70 μm or more, from the viewpoint of the strength and handling properties of the adhesive tape. Furthermore, in some embodiments, the thickness of the base material layer may be, for example, more than 105 μm, more than 115 μm, 130 μm or more, 140 μm or more, 150 μm or more, 160 μm or more, 200 μm or more, 250 μm or more, or 300 μm or more. The above thickness of the base material layer can be preferably applied to adhesive tapes used for protecting and bundling wires in wire harnesses. As the base material layer becomes thicker, cracking of the base material tends to occur more easily when the wire harness is bent and deformed at low temperatures, and the value of the bending stiffness at room temperature also tends to increase. However, according to the technology disclosed herein, even in embodiments with a relatively large base material thickness, it is possible to realize an adhesive tape that balances easy deformation in the low temperature range, good flexibility in the room temperature range, and deformation resistance in the high temperature range. Furthermore, if a wire harness is used without an external protective material such as corrugated tubing, and the wire harness is used in a manner where its outer surface is exposed (i.e., the back of the adhesive tape is exposed and not covered by protective material), for example, if the wire harness is routed in a way that it may interfere with the body of an automobile or other components, the back of the adhesive tape may be repeatedly rubbed due to such interference. Increasing the thickness of the base material layer can be advantageous from the viewpoint of improving the durability (abrasion resistance) of the adhesive tape in such usage scenarios.

[0085] The surface of the substrate layer on which the adhesive layer is placed may be subjected to conventionally known surface treatments as needed, such as corona discharge treatment, plasma treatment, ultraviolet irradiation treatment, acid treatment, alkali treatment, application of a primer, or antistatic treatment. Such surface treatments may be treatments to improve the adhesion between the substrate layer and the adhesive layer, in other words, the anchoring ability of the adhesive layer to the substrate layer. The composition of the primer is not particularly limited and can be appropriately selected from known ones. The thickness of the undercoat layer is not particularly limited, but is usually preferably 0.01 μm to 2 μm, more preferably 0.1 μm to 1 μm.

[0086] In a PVC adhesive tape having an adhesive layer on only one surface of the base layer, the surface (back) on the side without the adhesive layer may be subjected to conventionally known surface treatments such as release treatment or antistatic treatment, as needed. For example, by providing a release treatment layer such as a long-chain alkyl or silicone-based layer on the back of the base layer, the unwinding force of the PVC adhesive tape wound in a roll can be reduced. Furthermore, for purposes such as improving printability, reducing light reflectivity, and improving overlapping properties, the back surface may be subjected to treatments such as corona discharge treatment, plasma treatment, ultraviolet irradiation treatment, acid treatment, or alkali treatment.

[0087] <Adhesive layer> The adhesive layer in the technology disclosed herein is typically a layer composed of a material (adhesive) that exhibits a soft solid (viscoelastic) state at temperatures near room temperature and readily adheres to an adherend under pressure. The adhesive referred to herein is generally defined as having a complex tensile modulus E, as defined in "CA Dahlquist, “Adhesion: Fundamentals and Practice”, McLaren & Sons, (1966) p. 143". * (1Hz) < 10 7 dyne / cm 2 It is a material that has properties that satisfy the above conditions (typically, a material that has the above properties at 25°C).

[0088] The adhesive layer in the technology disclosed herein may be an adhesive layer formed from various forms of adhesive compositions, such as water-dispersible adhesive compositions, water-soluble adhesive compositions, solvent-type adhesive compositions, hot-melt adhesive compositions, and active-energy ray-curable adhesive compositions. Here, "active energy rays" refers to energy rays with energy capable of causing chemical reactions such as polymerization reactions, crosslinking reactions, and initiator decomposition, and is a concept that includes light such as ultraviolet rays, visible light, and infrared rays, as well as radiation such as alpha rays, beta rays, gamma rays, electron beams, neutron rays, and X-rays. An adhesive layer formed from a water-dispersible adhesive composition is preferred because it suppresses the migration of plasticizers in the PVC film to the adhesive layer and makes it easier to suppress changes in adhesive strength over time.

[0089] (Base polymer) The type of adhesive constituting the above adhesive layer is not particularly limited. The above adhesive may contain one or more of the following rubber-like polymers known in the field of adhesives, such as rubber polymers, acrylic polymers, polyester polymers, urethane polymers, polyether polymers, silicone polymers, polyamide polymers, and fluorine polymers, as the base polymer (main component among the polymer components). Here, a rubber-based adhesive refers to an adhesive that contains a rubber-based polymer as the base polymer. The same applies to acrylic adhesives and other adhesives. Furthermore, an acrylic polymer refers to a polymer that contains monomer units derived from a monomer having at least one (meth)acryloyl group in one molecule (acrylic monomer) in its polymer structure, and typically refers to a polymer that contains monomer units derived from acrylic monomers in a proportion of more than 50% by mass. Note that the above (meth)acryloyl group refers comprehensively to acryloyl groups and methacryloyl groups.

[0090] In some embodiments, the adhesive layer is formed from a water-dispersible adhesive composition comprising a rubber latex or acrylic polymer emulsion and a tackifying resin emulsion. Using such a rubber-based or acrylic adhesive, a PVC adhesive tape exhibiting good adhesive properties can be obtained. Such a PVC adhesive tape may, for example, exhibit the ability to prevent end delamination over a long period. In some preferred embodiments, the rubber latex includes natural rubber latex and styrene-butadiene rubber latex.

[0091] (Rubber-based polymer) The adhesive layer of the PVC adhesive tape disclosed herein may preferably be an adhesive layer mainly composed of a rubber-based adhesive (rubber-based adhesive layer). The rubber-based adhesive may contain one or more rubber-based polymers selected from natural rubber and synthetic rubber. In this specification, "main component" refers to a component present in more than 50% by mass unless otherwise specified. Both natural rubber and synthetic rubber can be used as the rubber-based polymer. As natural rubber, any known material that can be used in an adhesive composition can be used without particular limitation. The term "natural rubber" here is not limited to unmodified natural rubber, but includes modified natural rubber, for example, that has been modified with an acrylic acid ester. Unmodified natural rubber and modified natural rubber may be used in combination. As synthetic rubber, any known material that can be used in an adhesive composition can be used without particular limitation. Preferred examples include styrene-butadiene rubber (SBR), styrene-isoprene rubber, and chloroprene rubber. These synthetic rubbers may be unmodified or modified (e.g., carboxylated). Rubber-based polymers can be used individually or in combination of two or more types.

[0092] PVC adhesive tapes according to several preferred embodiments have a rubber adhesive layer formed from a water-dispersible rubber adhesive composition obtained by compounding a rubber latex with tackifying resins and other additives as needed. The rubber latex may be a dispersion of various known rubber polymers in water. Both natural rubber latex and synthetic rubber latex can be used. As the natural rubber latex, any known material that can be used in adhesive compositions can be used without particular limitation. The term "natural rubber latex" here is not limited to unmodified natural rubber latex, but is a concept that includes modified natural rubber latex, for example, modified with acrylic acid esters. Unmodified natural rubber latex and modified natural rubber latex may be used in combination. As the synthetic rubber latex, any known material that can be used in adhesive compositions can be used without particular limitation. Preferred examples include styrene-butadiene rubber latex (SBR latex), styrene-isoprene rubber latex, and chloroprene rubber latex. The synthetic rubber contained in these synthetic rubber latex may be unmodified or modified (e.g., carboxylated). Rubber latex can be used individually or in combination of two or more types.

[0093] Some preferred embodiments of rubber-based adhesive compositions (e.g., water-dispersible rubber-based adhesive compositions) contain both natural rubber and synthetic rubber as rubber polymers. Such adhesive compositions can form PVC adhesive tapes exhibiting good adhesive properties. For example, PVC adhesive tapes with adhesive properties suitable for applications such as protection and bundling of electric wires and pipes, coating of corrugated tubes as described above, and electrical insulation can be formed. The mass ratio of natural rubber to synthetic rubber (natural rubber:synthetic rubber) is preferably in the range of approximately 10:90 to 90:10, more preferably in the range of approximately 20:80 to 80:20, and even more preferably in the range of approximately 30:70 to 70:30. SBR can be preferably used as the synthetic rubber.

[0094] (Acrylic polymer) In other preferred embodiments, an adhesive layer mainly composed of an acrylic adhesive (acrylic adhesive layer) may be used as the adhesive layer. Using an acrylic adhesive makes it easier to obtain an adhesive tape with excellent heat resistance. As the acrylic polymer contained in the acrylic adhesive, a (meth)acrylic acid ester polymer having (meth)acrylic acid ester (acrylic acid ester, methacrylic acid ester) as the monomer main component can be used. The acrylic polymer used in the acrylic adhesive is preferably in the form of an emulsion-type acrylic polymer (acrylic polymer emulsion).

[0095] As the acrylic polymer, a polymer of alkyl (meth)acrylate, in particular, in which alkyl (meth)acrylate is the main monomer component, can be preferably used. The alkyl (meth)acrylate polymer may be a polymer (homopolymer) of only one type of alkyl (meth)acrylate, or it may be a copolymer of alkyl (meth)acrylate with other (meth)acrylate esters such as cycloalkyl (meth)acrylate, aryl (meth)acrylate, or monomers (copolymerizable monomers) that can copolymerize with alkyl (meth)acrylate. In other words, in an alkyl (meth)acrylate polymer, monomer components such as alkyl (meth)acrylate may be used alone, or two or more may be used in combination.

[0096] Examples of alkyl (meth)acrylate esters in acrylic polymers include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, s-butyl (meth)acrylate, t-butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and (meth) C(meth)acrylate such as isooctyl acrylate, nonyl (meth)acrylate, isononyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, undecyl (meth)acrylate, dodecyl (meth)acrylate, tridecyl (meth)acrylate, tetradecyl (meth)acrylate, pentadecyl (meth)acrylate, hexadecyl (meth)acrylate, heptadecyl (meth)acrylate, octadecyl (meth)acrylate, nonadecyl (meth)acrylate, eicosyl (meth)acrylate, etc. 1-20 Examples include alkyl esters, among others. 2-14 Alkyl esters are preferred, and (meth)acrylate C 2-10 Alkyl esters are more preferred. Among alkyl (meth)acrylate esters, butyl (meth)acrylate and 2-ethylhexyl (meth)acrylate are particularly preferred. Note that the above "C 1-20 "C" etc. X-Y The notation " means that the number of carbon atoms is between X and Y, and (meth)acrylic acid C X-Y Alkyl esters refer to alkyl (meth)acrylate esters having an alkyl group with X to Y carbon atoms at the ester terminus.

[0097] The above-mentioned (meth)acrylic acid ester is used as the main monomer component, and the proportion of (meth)acrylic acid ester (particularly alkyl (meth)acrylic acid ester) is typically 50% by mass or more relative to the total amount of monomer components, preferably 80% by mass or more, and more preferably 90% by mass or more, from the viewpoint of adhesion and cohesiveness.

[0098] In acrylic polymers, copolymerizable monomers that can copolymerize with alkyl (meth)acrylates include, for example, carboxyl group-containing monomers such as (meth)acrylic acid (acrylic acid, methacrylic acid), itaconic acid, maleic acid, fumaric acid, and crotonic acid; acid anhydride group-containing monomers such as maleic anhydride and eicotanoic anhydride; cyanoacrylate monomers such as acrylonitrile and methacrylonitrile; aminoalkyl (meth)acrylate monomers such as aminoethyl (meth)acrylate, N,N-dimethylaminoethyl (meth)acrylate, and t-butylaminoethyl (meth)acrylate; and (meth)acrylamide, N,N-dimethyl(meth)acrylamide, N-butyl(meth)acrylamide, and N-hydroxy(meth)acrylamide. (N-substituted)amide monomers such as N-methylol(meth)acrylamide and N,N-dimethylaminopropyl(meth)acrylamide; vinyl ester monomers such as vinyl acetate and vinyl propionate; styrene monomers such as styrene, α-methylstyrene, and vinyltoluene; hydroxyl group-containing monomers such as 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate; epoxy group-containing acrylic monomers such as glycidyl (meth)acrylate; alkoxyalkyl (meth)acrylate monomers such as methoxyethyl (meth)acrylate and ethoxyethyl (meth)acrylate; lactone monomers such as ε-caprolactone acrylate; ethylene, propylene, isopyroxene Examples include olefin monomers such as lene and butadiene; vinyl ether monomers such as methyl vinyl ether and ethyl vinyl ether; morpholine (meth)acrylate; and heterocyclic vinyl monomers such as N-vinyl-2-pyrrolidone, N-vinylpyridine, N-vinylpiperidone, N-vinylpyrimidine, N-vinylpiperazine, N-vinylpyrazine, N-vinylpyrrole, N-vinylimidazole, and N-vinyloxazole. The above copolymerizable monomers can be used individually or in combination of two or more. Preferred examples of the above copolymerizable monomers include carboxyl group-containing monomers (specific examples being acrylic acid and / or methacrylic acid).

[0099] Furthermore, in acrylic polymers, polyfunctional monomers such as hexanediol di(meth)acrylate, (poly)ethylene glycol di(meth)acrylate, (poly)propylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, pentaerythritol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, epoxy acrylate, polyester acrylate, urethane acrylate, divinylbenzene, butyl di(meth)acrylate, and hexyl di(meth)acrylate may be used as copolymerizable monomers.

[0100] The polymerization method for acrylic polymers is not particularly limited, and various conventionally known polymerization methods can be used as appropriate. For example, thermal polymerization such as solution polymerization, emulsion polymerization, and bulk polymerization (typically carried out in the presence of a thermal polymerization initiator); photopolymerization carried out by irradiation with light such as ultraviolet light (typically carried out in the presence of a photopolymerization initiator); and radiation polymerization carried out by irradiation with radiation such as beta rays and gamma rays can be used as appropriate. Two or more polymerization methods may be combined (for example, in steps).

[0101] When the acrylic polymer constituting the acrylic adhesive is an emulsion-type acrylic polymer, the emulsion-type acrylic polymer may be an acrylic polymer prepared by polymerization methods other than emulsion polymerization (such as solution polymerization) and then emulsified using an emulsifier as needed. However, it is preferable to use an acrylic polymer prepared by emulsion polymerization.

[0102] Polymerization methods for acrylic polymers include general one-step polymerization, continuous dropwise polymerization, and segmented dropwise polymerization. Any of these methods may be used, or multiple polymerization methods may be combined. Furthermore, the polymerization reaction may be carried out in steps; for example, polymerization may be carried out once, and then further polymerization may be carried out by adding monomer components.

[0103] When preparing acrylic polymers by emulsion polymerization, one or more known emulsifiers can be used in combination during polymerization. In particular, it is preferable to use a reactive emulsifier that has a group capable of copolymerizing with (meth)acrylic acid ester (for example, a group containing an ethylenically unsaturated bond site). Since the reactive emulsifier is bonded to the molecular chains in the adhesive composition (especially the molecular chains of the acrylic polymer), the precipitation and migration of the emulsifier on the surface of the adhesive layer are suppressed or prevented, and a decrease in adhesive strength and contamination of the adherend by the emulsifier can be effectively suppressed or prevented. Therefore, it is preferable that the emulsion-type acrylic polymer used in the technology disclosed herein is prepared by emulsion polymerization of monomer components in the presence of a reactive emulsifier.

[0104] Reactive emulsifiers can be any emulsifier that has emulsifying properties and a group that can copolymerize with (meth)acrylic acid esters. Examples include anionic emulsifiers such as sodium lauryl sulfate, ammonium lauryl sulfate, sodium dodecylbenzenesulfonate, sodium polyoxyethylene alkyl ether sulfate, ammonium polyoxyethylene alkylphenyl ether sulfate, sodium polyoxyethylene alkylphenyl ether sulfate, and sodium polyoxyethylene alkyl sulfosuccinate; nonionic emulsifiers such as polyoxyethylene alkyl ethers, polyoxyethylene alkylphenyl ethers, polyoxyethylene fatty acid esters, and polyoxyethylene polyoxypropylene block polymers; and reactive emulsifiers that have a form in which a radical polymerizable functional group (radical reactive group) such as a propenyl group or an allyl ether group is introduced (or is equivalent to such a form). The above reactive emulsifiers can be used individually or in combination of two or more.

[0105] Furthermore, there are no particular restrictions on emulsifiers other than the reactive emulsifiers mentioned above (non-reactive emulsifiers), and they can be appropriately selected from known emulsifiers. Specific examples of non-reactive emulsifiers include anionic emulsifiers such as sodium lauryl sulfate, ammonium lauryl sulfate, sodium dodecylbenzenesulfonate, sodium polyoxyethylene alkyl ether sulfate, ammonium polyoxyethylene alkylphenyl ether sulfate, sodium polyoxyethylene alkylphenyl ether sulfate, and sodium polyoxyethylene alkyl sulfosuccinate; nonionic emulsifiers such as polyoxyethylene alkyl ether, polyoxyethylene alkylphenyl ether, polyoxyethylene fatty acid ester, and polyoxyethylene polyoxypropylene block polymer; and nonionic anionic emulsifiers such as sodium polyoxyethylene alkyl ether sulfate, ammonium polyoxyethylene alkylphenyl ether sulfate, sodium polyoxyethylene alkylphenyl ether sulfate, and sodium polyoxyethylene alkyl sulfosuccinate. These non-reactive emulsifiers can be used individually or in combination of two or more.

[0106] The amount of emulsifier (especially reactive emulsifier) ​​used is not limited to a specific range, as the amount is appropriately selected depending on the emulsion. However, it is generally appropriate to use 0.1 to 20 parts by mass (preferably 1 to 10 parts by mass) per 100 parts by mass of monomer mixture.

[0107] Furthermore, polymerization initiators and chain transfer agents may be used during polymerization to obtain acrylic polymers (preferably emulsion-type acrylic polymers). The polymerization initiators and chain transfer agents are not particularly limited and can be appropriately selected from known ones. Examples of polymerization initiators include 2,2'-azobisisobutyronitrile, 2,2'-azobis(2-methylpropionamidine) disulfide, 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(2-methylbutyronitrile), 1,1'-azobis(cyclohexane-1-carbonnitrile), 2,2'-azobis(2,4,4-trimethylpentane), dimethyl-2,2'-azobis(2-methylpropionate), 2,2'-azobis[2-methyl-N-(phenylmethyl)-propionamidine]dihydrochloride, and 2,2'-azobis[2-(3,4,5,6-tetrahydropyrimidine-2-yl)propane]di Examples of polymerization initiators include azo-based polymerization initiators such as hydrochloride and 2,2'-azobis[2-(2-imidazolin-2-yl)propane]; persulfate-based polymerization initiators such as potassium persulfate and ammonium persulfate; peroxide-based polymerization initiators such as benzoyl peroxide, hydrogen peroxide, t-butyl hydroperoxide, di-t-butyl peroxide, t-butyl peroxybenzoate, dicumyl peroxide, 1,1-bis(t-butylperoxy)-3,3,5-trimethylcyclohexane, 1,1-bis(t-butylperoxy)cyclododecane, 3,3,5-trimethylcyclohexanoyl peroxide, and t-butyl peroxypivalate; and redox-based polymerization initiators composed of persulfates and sodium bisulfite. Polymerization initiators can be used individually or in combination of two or more. The amount of polymerization initiator used is not particularly limited and can be appropriately selected depending on the polymerization method, polymerization reactivity, type and proportion of monomer components, type of polymerization initiator, etc. For example, it can be appropriately selected from the range of 0.005 to 1 part by mass per 100 parts by mass of monomer mixture.

[0108] Furthermore, as a chain transfer agent, one or more selected from, for example, lauryl mercaptan, glycidyl mercaptan, mercaptoacetic acid, 2-mercaptoethanol, thioglycolic acid, 2-ethylhexyl thioglycolate, 2,3-dimethylcapto-1-propanol, etc., may be used.

[0109] (Adhesive-forming resin) The adhesive layer in the technology disclosed herein (e.g., a rubber-based adhesive layer or an acrylic-based adhesive layer) may contain a tackifying resin in addition to the base polymer as described above. As the tackifying resin, a suitable one can be selected from various known tackifying resins. For example, one or more tackifying resins selected from various tackifying resins such as rosin resins, petroleum resins, terpene resins, phenolic resins, coumarone indene resins, and ketone resins can be used. In embodiments in which the adhesive layer is formed from a water-dispersible adhesive composition (preferably a water-dispersible rubber-based adhesive composition), a tackifying resin emulsion is preferably used as the tackifying resin.

[0110] Examples of rosin-based resins include rosin derivatives such as disproportionated rosin, hydrogenated rosin, polymerized rosin, maleated rosin, and fumarated rosin, as well as phenol-modified rosin and rosin esters. Examples of phenol-modified rosin include those obtained by adding phenols to natural rosin or rosin derivatives, or phenol-modified rosin obtained by reacting resol-type phenolic resins with natural rosin or rosin derivatives. Examples of rosin esters include esterified products obtained by reacting the above-mentioned rosin-based resins with polyhydric alcohols. It should be noted that rosin-phenolic resins can also be esterified products.

[0111] Examples of terpene resins include terpene resins (α-pinene resin, β-pinene resin, limonene resin, etc.), terpene phenol resins, aromatically modified terpene resins, and hydrogenated terpene resins.

[0112] Examples of petroleum-based resins include aliphatic (C5) petroleum resins, aromatic (C9) petroleum resins, aliphatic / aromatic copolymer (C5 / C9) petroleum resins, hydrogenated versions of these (for example, alicyclic petroleum resins obtained by hydrogenating aromatic petroleum resins), and various modified versions of these (for example, maleic anhydride modified versions).

[0113] Examples of phenolic resins include condensates of various phenols such as phenol, m-cresol, 3,5-xylenol, p-alkylphenol, and resorcinol with formaldehyde. Other examples of phenolic resins include resols obtained by addition reactions of the above phenols with formaldehyde under an alkaline catalyst, and novolacs obtained by condensation reactions of the above phenols with formaldehyde under an acid catalyst.

[0114] Examples of coumarone indene resins include coumarone indene resin, hydrogenated coumarone indene resin, phenol-modified coumarone indene resin, and epoxy-modified coumarone indene resin.

[0115] Examples of ketone resins include those produced by the condensation of ketones (for example, aliphatic ketones such as methyl ethyl ketone, methyl isobutyl ketone, and acetophenone, and alicyclic ketones such as cyclohexanone and methylcyclohexanone) with formaldehyde.

[0116] In some preferred embodiments (for example, embodiments using rubber-based adhesives), a petroleum-based resin (preferably an aliphatic (C5) petroleum resin) and a phenolic resin (preferably an alkylphenolic resin) are used in combination as the tackifying resin. In such embodiments, the ratio of the two is not particularly limited. For example, the ratio of the content B of petroleum-based resin to the content A of phenolic resin (B / A) can be 1 or more, preferably 2 or more, more preferably 2.5 or more, and also suitable if 15 or less, and preferably 9 or less. In some other embodiments (for example, embodiments using acrylic-based adhesives), it is preferable to use a rosin-based resin as the tackifying resin.

[0117] The softening temperature of the tackifying resin used is not particularly limited. In some embodiments (for example, embodiments using rubber-based adhesives), for example, a tackifying resin with a softening point of 60 to 160°C can be used. Alternatively, a tackifying resin that is liquid at room temperature may be used. From the viewpoint of achieving a good balance between cohesive force and low-temperature characteristics (for example, unwinding and adhesive strength at low temperatures), a tackifying resin with a softening point of 60 to 140°C (more preferably 80 to 120°C) can be preferably used. For example, the use of a petroleum-based resin with a softening point within the above range is preferred. In some other embodiments (for example, embodiments using acrylic-based adhesives), a tackifying resin with a softening point of approximately 200°C or less (more preferably approximately 180°C or less) can be preferably used. The lower limit of the softening point of such a tackifying resin is not particularly limited and may be, for example, approximately 135°C or higher (even more preferably approximately 140°C or higher). The softening point of the tackifying resin can be measured based on the softening point test method (ring-ball method) specified in JIS K2207.

[0118] The ratio of polymer components to tackifying resin in the adhesive layer is not particularly limited and can be appropriately determined depending on the application. In some embodiments, the content of tackifying resin per 100 parts by mass of polymer components can be, for example, 20 parts by mass or more, based on non-volatile content, and is usually appropriate to be 50 parts by mass or more. From the viewpoint of obtaining a higher usage effect, the amount of tackifying resin used per 100 parts by mass of polymer components can be 80 parts by mass or more, and may be 100 parts by mass or more. On the other hand, from the viewpoint of low-temperature characteristics, etc., it is usually appropriate to use 200 parts by mass or less, and preferably 150 parts by mass or less, for the amount of tackifying resin used per 100 parts by mass of polymer components. In some other embodiments, the amount of tackifying resin used can be appropriately set in the range of about 1 to 100 parts by mass per 100 parts by mass of base polymer (preferably acrylic polymer). From the viewpoint of cohesive force, it is appropriate to use 50 parts by mass or less per 100 parts by mass of base polymer (preferably acrylic polymer), and may be 20 parts by mass or less, or 10 parts by mass or less.

[0119] (Crosslinking agent) In the technology disclosed herein, the adhesive composition used to form the adhesive layer may optionally contain a crosslinking agent. The type of crosslinking agent is not particularly limited and can be appropriately selected from conventionally known crosslinking agents. Examples of such crosslinking agents include isocyanate crosslinking agents, epoxy crosslinking agents, oxazoline crosslinking agents, aziridine crosslinking agents, melamine crosslinking agents, peroxide crosslinking agents, urea crosslinking agents, metal alkoxide crosslinking agents, metal chelate crosslinking agents, metal salt crosslinking agents, carbodiimide crosslinking agents, hydrazine crosslinking agents, amine crosslinking agents, and silane coupling agents. Among these, isocyanate crosslinking agents, epoxy crosslinking agents, oxazoline crosslinking agents, aziridine crosslinking agents, and melamine crosslinking agents are preferred, isocyanate crosslinking agents and epoxy crosslinking agents are more preferred, and epoxy crosslinking agents are particularly preferred. The crosslinking agent can be used alone or in combination of two or more types.

[0120] The amount of crosslinking agent used is not particularly limited. For example, it can be approximately 10 parts by mass or less per 100 parts by mass of the base polymer (preferably an acrylic polymer), preferably in the range of approximately 0.005 to 10 parts by mass, and more preferably in the range of approximately 0.01 to 5 parts by mass.

[0121] (Other additives) Furthermore, in embodiments where a water-dispersible adhesive composition is used as the adhesive composition, it is preferable to use a protective colloid such as a water-soluble salt of casein in the water-dispersible adhesive composition from the viewpoint of insulating properties and moisture resistance.

[0122] In addition, the above-mentioned adhesive layer may contain, as needed, various additives common in the field of adhesives, such as viscosity modifiers (thickeners, etc.), leveling agents, plasticizers, softeners, colorants such as pigments and dyes, light stabilizers, anti-aging agents, antioxidants, water-resistant agents, antistatic agents, foaming agents, defoaming agents, surfactants, and preservatives.

[0123] The adhesive layer can be formed by employing various conventionally known methods as appropriate. For example, a direct method can be used to form the adhesive layer by directly applying (typically coating) the adhesive composition to the substrate (typically a PVC film) and drying it. Alternatively, a transfer method can be used in which the adhesive composition is applied to a release surface (release surface) and dried to form an adhesive layer on the surface, and the adhesive layer is then transferred to the substrate. These methods can also be combined. The release surface can be the surface of a release liner or the back surface of a release-treated support substrate.

[0124] The adhesive composition can be applied using known or conventional coaters, such as gravure roll coaters, reverse roll coaters, kiss roll coaters, dip roll coaters, bar coaters, knife coaters, and spray coaters. The adhesive layer is typically formed continuously, but depending on the purpose and application, it may be formed in regular or random patterns such as dots or stripes.

[0125] While not particularly limited, the thickness of the adhesive layer is typically 2 μm or more, usually 5 μm or more is appropriate, preferably 10 μm or more, and more preferably 15 μm or more. The greater the thickness of the adhesive layer, the easier it is to exhibit good adhesive properties, for example, it is easier to improve the resistance to terminal peeling. The upper limit of the thickness of the adhesive layer may be, for example, 100 μm or less, usually 50 μm or less is appropriate, preferably 40 μm or less, more preferably 30 μm or less, and even more preferably 25 μm or less. By limiting the thickness of the adhesive layer, weight reduction can be achieved. The above range of adhesive layer thickness is preferably applicable to PVC adhesive tapes used for, for example, protection and bundling of electric wires, pipes, etc., coating of corrugated tubes as described above, electrical insulation, etc. In particular, it is preferably applicable to adhesive tapes used for protection and bundling of electric wires in wire harnesses.

[0126] Thickness T of the adhesive layer PSA [μm] relative to the thickness T of the substrate layer S [μm] ratio (TS / T PSA ) is not particularly limited and can be set to an appropriate range in which the effects of the technologies disclosed herein are achieved. In some embodiments, the above ratio (T S / T PSA The ratio (T) is preferably in the range of 6 to 13. S / T PSA By setting the ratio (T) to 6 or higher, it tends to be easier to obtain high wear resistance. S / T PSA When the ratio (T) is 13 or less, good adhesive properties (adhesion, etc.) and flexibility are easily obtained. S / T PSA ) is more preferably 8 or more, may be 9 or more, may be 10 or more, or may be 11 or more. Also, ratio (T S / T PSA ) is more preferably 12 or less, may be 10.5 or less, or 9.5 or less.

[0127] The total thickness of the adhesive tape (including the thickness of the base layer and the adhesive layer, but not the thickness of the release liner) is the sum of the above-mentioned base layer thickness and adhesive layer thickness, and may be in the range of approximately 40 to 600 μm. From the viewpoint of ease of wrapping the adhesive tape around wires, etc., in some embodiments, the total thickness of the adhesive tape may be, for example, 550 μm or less, 500 μm or less, 450 μm or less, 400 μm or less, 350 μm or less, 300 μm or less, 250 μm or less, or 200 μm or less. The total thickness of the adhesive tape may be, for example, 50 μm or more, 75 μm or more, 90 μm or more, 120 μm or more, 150 μm or more, or 180 μm or more. The above total thickness of the adhesive tape can preferably be applied to adhesive tapes used for protecting and bundling wires in wire harnesses.

[0128] <Application> The adhesive tape disclosed herein can achieve a good balance of suitable properties over a wide temperature range (easy deformation at low temperatures, good flexibility at room temperature, and deformation resistance at high temperatures), making it suitable for applications such as protecting and bundling electric wires and pipes, covering corrugated tubes that surround and protect electric wires, and electrical insulation. Particularly preferred applications include bundling and fixing wire harnesses (for example, wire harnesses for automobiles and other vehicles or aircraft, especially wire harnesses for vehicles and aircraft equipped with internal combustion engines), and covering, bundling, and fixing corrugated tubes for wire harnesses. The above wire harness may be used in the vicinity of the internal combustion engine (for example, in the engine room). Furthermore, the adhesive tape disclosed herein is not limited to the above applications and can be suitably used in various fields where PVC adhesive tapes have conventionally been used, such as insulation, fixing, marking, and identification of interlayers and outer surfaces of electrical components (transformers, coils, etc.) and electronic components.

[0129] When the adhesive tape disclosed herein is used in a wire harness, the wire harness may be used in a manner in which the back surface of the adhesive tape is covered with a protective material (for example, with an outer protective material attached), or in a manner in which the back surface is exposed without being covered with a protective material. In some preferred embodiments of the wire harness, the back surface of the adhesive tape is exposed and not covered with a protective material. The adhesive tape disclosed herein has good crack resistance at low temperatures and good deformation resistance at high temperatures, so it does not require the protective material that was conventionally attached around the wire harness to avoid a decrease in the protective performance of the adhesive tape due to cracking or deformation. A wire harness without protective material can be made more productive and lighter.

[0130] The following describes several embodiments relating to the present invention, but the present invention is not intended to be limited to those examples shown. In the following description, "parts" and "%" refer to mass unless otherwise specified.

[0131] <Example 1> (Production of PVC film) Each of the raw materials shown in Table 1 was weighed and mixed to achieve the composition shown in the same table (i.e., a composition containing 40 parts plasticizer, 5 parts elastomer A, 10 parts filler, 2 parts stabilizer, 0.3 parts stabilizing agent, and 1.7 parts pigment per 100 parts polyvinyl chloride (PVC)), kneaded, and then formed into a long film shape with a thickness of 180 μm using a calendering machine at a molding temperature of 150°C to obtain the PVC film (substrate) for this example. For the PVC, we used product name "S-70" (product of Taiwan Plastics Co., Ltd., degree of polymerization 1350). For the plasticizer, we used diisononyl phthalate (product name "DINP", manufactured by J-Plus Co., Ltd.). For elastomer A, we used thermoplastic polyurethane copolymer (thermoplastic polyurethane elastomer (TPU) (water-resistant polyester type), product name "Elastoran C90A10", manufactured by BASF Japan Ltd., durometer hardness A90, urethane bond fraction 16 mol%). For the filler, we used calcium carbonate (product name "CS1600", manufactured by Li Xiang Co., Ltd.). For the stabilizer, we used product name "OW-5000LTS" (composite stabilizer for PVC) (manufactured by Sakai Chemical Co., Ltd.). For the stabilizing agent, we used product name "ADEKA Stab ADK1500" (manufactured by ADEKA Corporation). For the pigment, we used product name "BC-3082" (black pigment manufactured by Taiwan DIC Co., Ltd.).

[0132] (Preparation of adhesive composition) 100 parts of natural rubber latex (product name "HYTEX," obtained from Nomura Trading Co., Ltd.) and 1 part of emulsifier (product name "Nopco 38-C," manufactured by Sunnopco) were mixed at 30°C under a nitrogen atmosphere for 2 hours. Then, a mixture of 10 parts of methyl methacrylate and 1 part of cumene hydroperoxide was added and stirred for 1 hour. Furthermore, 0.4 parts of tetraethylenepentamine were added and stirred for 4 hours to obtain acrylic-modified natural rubber latex. 20 parts of this acrylic-modified natural rubber latex (solids content) was mixed with 20 parts of natural rubber latex (product name "HYTEX," obtained from Nomura Trading Co., Ltd.) (solids content) and 60 parts of styrene-butadiene copolymer latex (product name "2108," manufactured by JSR Corporation) (solids content) to prepare a rubber-based latex.

[0133] As a tackifying resin, a resin solution was prepared by dissolving 80 parts of aliphatic petroleum resin (product name "RB100", manufactured by JXTG Energy Corporation) and 20 parts of alkylphenol resin (product name "Tackiroll 201", manufactured by Taoka Chemical Industry Co., Ltd.) in 40 parts of heptane. In addition, an aqueous casein ammonia solution was prepared by heating and dissolving 4 parts of casein, 15 parts of 28% aqueous ammonia, and 60 parts of water in a solution of 100 parts casein at 70°C. This was used as a protective colloid. The obtained aqueous casein ammonia solution was cooled to 40°C, and 8 parts of ammonium salt of hydrogenated rosin (dihydroabietic acid content 60%) was mixed in as an emulsifier. This was then added to the above resin solution, and the mixture was stirred at 40°C at a rotation speed of 800 rpm for 1 hour using a T·K homodisperser (manufactured by Tokushu Kika Kogyo Co., Ltd.) to prepare a tackifying resin emulsion.

[0134] A water-based adhesive composition was obtained by mixing 100 parts (based on solid content) of the rubber-based latex obtained above with 100 parts (based on solid content) of a tackifying resin emulsion.

[0135] (Making adhesive tape) The adhesive composition was applied to one surface of the PVC film using a comma direct coater, dried, and wound up to a length sufficient for the evaluation test described later, thereby obtaining a raw material roll of the adhesive tape according to this example. The amount of adhesive composition applied was adjusted so that the thickness of the adhesive layer formed after drying was 20 μm. The raw material roll was cut (slit) to a width of 19 mm to obtain an adhesive tape according to this example having an adhesive layer on one surface of the PVC film.

[0136] <Examples 2-14 and Comparative Examples 1-4> Adhesive tapes for each example were prepared in the same manner as in Example 1, except that the composition of the PVC film was as shown in Tables 1 to 3. For elastomer B, a thermoplastic polyurethane copolymer (TPU (polyester-based), product name "Elastoran S80A10", manufactured by BASF Japan Ltd., durometer hardness A80, urethane bond fraction 13 mol%) was used. For elastomer C, a thermoplastic polyurethane copolymer (TPU (polyether-based), product name "Elastoran 1180A10 Clear", manufactured by BASF Japan Ltd., durometer hardness A80, urethane bond fraction 12 mol%) was used. For elastomer D, a thermoplastic polyester copolymer (thermoplastic polyester elastomer (TPEE), product name "Hytrel 4001", manufactured by Toray DuPont Ltd., durometer hardness D40) was used. Elastomer E was a (meth)acrylic acid ester-butadiene-styrene copolymer (methyl methacrylate-butadiene-styrene copolymer (MBS), product name "KaneAce B-22", manufactured by Kaneka Corporation). Elastomer F was an ethylene-vinyl acetate copolymer (product name "Green Effect 630P", obtained from Sanyo Trading Co., Ltd.).

[0137] <Rating> (Low-temperature bending test) Two 30cm lengths of fluororesin-insulated movable single-core wire (Junflon ETFE wire, finished outer diameter 1.12mm, insulation thickness 0.15mm (inner diameter 0.82mm), purchased from Misumi Corporation) were prepared. An evaluation sample was prepared by wrapping the adhesive tape to be evaluated (width 19mm) around the two wires in a half-wrap manner (a wrapping method in which half the width of the adhesive tape overlaps half the width of the adhesive tape already wrapped around the wires) while applying a load to one end of the tape. The load was set to 50g per 25μm of tape thickness. Next, the evaluation sample was left to stand in a -40°C environment for 30 minutes. Then, in the same temperature environment, the evaluation sample was held by both ends by hand and, as shown in Figure 2, the sample 50 was bent by hand until both ends made contact, while applying the approximate center of the longitudinal direction of the evaluation sample 50 to a 4 mm diameter iron rod 52 that was positioned perpendicular to the sample (so that the two wires contained in the sample 50 were aligned in the longitudinal direction of the iron rod 52, and the sample 50 was in contact with the iron rod 52). The time from when the bending of the sample 50 began until both ends made contact was approximately 3 seconds, and during that time, the bending proceeded at roughly the same speed. After the samples returned to room temperature, the folded areas were visually inspected, and the results were evaluated on the following three levels. A score of 2 or higher was considered a pass. 3 points: No cracks were observed in the adhesive tape. Points 2: Although there were some slight cracks in the adhesive tape, no exposed wires were observed. 1. A significant crack appeared in the adhesive tape, exposing the electrical wires.

[0138] (Measurement of bending stiffness at room temperature) The room-temperature bending stiffness was measured using a pure bending tester, model KES-FB2-S, manufactured by Kato Tech Co., Ltd., under conditions of 25°C. Specifically, a 100mm square sample was cut from the raw material (before slitting) of the adhesive tape to be evaluated, and baby powder was sprinkled on it to eliminate the tackiness of the adhesive surface. This sample was placed in a pure bending test machine, and as shown in Figure 3 (a schematic diagram of the apparatus viewed from above), the maximum bending curvature of sample 60 was 2.5cm. -1 The deformation rate of the curvature is 0.5 cm -1Under the condition of / sec, the movable chuck 64 was moved relative to the fixed chuck 62 in the following order: (1) forward bending of the front side (increased curvature), (2) return bending of the front side (decreased curvature), (3) forward bending of the back side (increased curvature), and (4) return bending of the back side (decreased curvature) (measured in one cycle). Here, the forward bending of the front side is the process of bending the sample with the substrate layer side facing inward, and the forward bending of the back side is the process of bending the sample with the adhesive layer side facing inward. For each of the forward bending of the front side and the forward bending of the back side, the bending moment [gf·cm / cm] per 1cm width of the sample was measured relative to the curvature [cm -1 The bending stiffness is calculated by dividing by [gf·cm], and the average of these values ​​is used to determine the sample's bending stiffness [gf·cm]. 2 [cm] was used.

[0139] (Measurement of deformation due to heat) The amount of thermal deformation was measured using a TP-201 thermal deformation tester manufactured by Tester Industries Co., Ltd., under conditions of 80°C. Specifically, a sample for measuring the amount of heat deformation was prepared by cutting the adhesive tape to be evaluated (width 19 mm) into 50 mm lengths and stacking them to a thickness of approximately 2.0 mm. After measuring the thickness of this sample (initial thickness T0), it was left to stand for 30 minutes in an environment of 80°C. Next, in the same temperature environment, as shown in Figure 4, the sample (reference numeral 70) was placed on a metal rod 72 with a semicircular cross-section (radius 5 mm), with the adhesive layer exposed side of the sample 70 facing the metal rod 72, and the metal rod 72 in contact with the center of the width of the sample 70. A load 74 of 2.0 kg was applied from above the sample 70 (substrate layer exposed side), and the thickness of the sample 70 (deformed thickness T1) was measured after standing for 5 minutes. The percentage change in the deformed thickness T1 compared to the initial thickness T0 was calculated as the amount of heat deformation [%]. In this experiment, the amount of heat deformation was measured using samples prepared by laminating five adhesive tapes (0.4 mm thick) in which the thickness of the PVC film in each of the above examples was changed to 360 μm and the thickness of the adhesive layer was changed to 40 μm.

[0140] For each example of adhesive tape, low-temperature bending tests, room-temperature bending stiffness, and heat deformation were evaluated. The evaluation results, along with the base material composition of the adhesive tape for each example, are shown in Tables 1 to 3.

[0141] [Table 1]

[0142] [Table 2]

[0143] [Table 3]

[0144] As shown in the table above, the adhesive tapes of Examples 1 to 14, which use a PVC film containing polyvinyl chloride and a plasticizer, and further containing TPU or TPEE as an elastomer, and have an adhesive layer on the PVC film, showed performance at an acceptable level (2 points or more) in the low temperature (-40°C) bending test, the bending stiffness at room temperature (23°C) was kept within an appropriate range, the amount of heat deformation at 80°C was small, and they showed a good balance of performance over a wide temperature range from low to high temperatures.

[0145] On the other hand, the adhesive tape of Comparative Example 1, which did not contain an elastomer, was prone to cracking at low temperatures and had high room-temperature bending stiffness. In Comparative Example 2, where the amount of plasticizer was increased with the intention of improving flexibility, the room-temperature bending stiffness decreased, but it did not receive an acceptable evaluation in the low-temperature bending test, and the amount of heat deformation increased compared to Comparative Example 1. Furthermore, in Comparative Examples 3 and 4, which used only elastomers that were neither TPU nor TPEE, Comparative Example 3 showed a further increase in room-temperature bending stiffness compared to Comparative Example 1, and Comparative Example 4 showed a significant increase in heat deformation.

[0146] Furthermore, both thermoplastic polyurethane and thermoplastic polyester elastomers are thermoplastic elastomers classified as multiblock copolymers, and belong to a different classification from elastomers such as methyl methacrylate-butadiene-styrene copolymer (MBS) and ethylene-vinyl acetate copolymer. Accordingly, the matters disclosed herein include adhesive tapes comprising a base layer made of a polyvinyl chloride film and an adhesive layer disposed on at least one surface of the base layer, wherein the base layer contains polyvinyl chloride, a plasticizer, and an elastomer, and the elastomer includes a multiblock copolymer type thermoplastic elastomer. The multiblock copolymer type thermoplastic elastomer can be used individually or in combination of two or more types. Thermoplastic polyurethane and thermoplastic polyester elastomer are preferred examples included in the concept of the multiblock copolymer type thermoplastic elastomer.

[0147] Although specific examples of the present invention have been described in detail above, these are merely illustrative and do not limit the scope of the claims. The technologies described in the claims include various modifications and changes to the specific examples illustrated above. [Explanation of Symbols]

[0148] 1 Adhesive tape 11 Base material layer 11A Front page 11B Second side 21 Adhesive layer 21A surface (adhesive surface) 50 samples 52 Horizontal bar 60 samples 62 Fixed Chuck 64 Mobile Chuck 70 samples 72 Metal rod 74 load

Claims

1. An adhesive tape comprising a base layer made of a polyvinyl chloride film and an adhesive layer disposed on at least one surface of the base layer, The thickness of the substrate layer is greater than 105 μm and less than 300 μm. The aforementioned substrate layer comprises polyvinyl chloride, a plasticizer, and an elastomer. The polyvinyl chloride content in the substrate layer is 40% by mass or more and 75% by mass or less. The content of the plasticizer in the substrate layer is 15% by mass or more and 30% by mass or less. The elastomer content in the substrate layer is 3.0% by mass or more and 30% by mass or less. The elastomer includes at least one of a thermoplastic polyurethane satisfying a durometer hardness of A75 or more and A95 or less and D25 or more and D45 or less, and a thermoplastic polyester elastomer satisfying at least one of a durometer hardness of A75 or more and A95 or less and D25 or more and D45 or less. The adhesive tape further comprises a filler in the base layer, wherein the filler content in the base layer is 3% by mass or more and 15% by mass or less.

2. The adhesive tape according to claim 1, wherein the elastomer comprises at least the thermoplastic polyurethane.

3. The adhesive tape according to claim 2, wherein the urethane bond fraction of the thermoplastic polyurethane is 10 mol% or more and 20 mol% or less.

4. The adhesive tape according to any one of claims 1 to 3, wherein the ratio of the elastomer content to the plasticizer content in the base layer is 0.1 or more and 1.5 or less by mass.

5. A wire harness comprising an electric wire and an adhesive tape according to any one of claims 1 to 4, which is wrapped around the electric wire.

6. The wire harness according to claim 5, wherein the back surface of the adhesive tape is exposed and not covered with a protective material.

Images