Adhesive tape, member, electronic device, and vehicle

Abstract

The purpose of the present invention is to provide an adhesive tape which can be recycled in a state in which the adhesive tape is adhered to an adherend having a thermoplastic resin, and in which the rate of reduction in tensile strength of a recycled plastic material after the adhesive tape is recycled is small. The present invention is a recyclable adhesive tape having a base material and an adhesive layer laminated on at least one surface of the base material, the adhesive tape containing 5-95 mass% of an olefin-based resin having an olefin-based monomer unit with respect to the total amount (100 mass%) of the adhesive tape, an adherend having a thermoplastic resin to which the adhesive tape is adhered and the adhesive tape satisfy the following relational expression (1). 0.8 < = sigmab / sigmaa < = 1.2 (1) In the relational expression (1), sigmaa is the tensile strength of the thermoplastic resin, and sigmab is the tensile strength of a test piece produced from the adhesive tape and the thermoplastic resin under predetermined conditions.

Description

Technical Field

[0001] The present invention relates to an adhesive tape, a component, an electronic device, and a vehicle. Background Art

[0002] Since the workability of an adhesive tape is excellent and the bonding reliability is high, it is widely used for component fixing purposes, temporary fixing purposes of components, label purposes for displaying product information, etc. in various industrial fields such as OA equipment, IT and home appliance products, and automobiles as a joining means. Generally, an adhesive tape has adhesiveness (peel strength) or tackiness (adhesiveness) as a basic characteristic, but depending on the use of the adhesive tape, various other characteristics may sometimes be required.

[0003] In addition, in recent years, with the increasing awareness of reducing environmental loads, the concept of "sustainable development" has been advocated. The reduction of environmental loads refers to, for example, reducing the adverse effects on the marine environment or ecosystem caused by the improper disposal of used plastic products, containers, etc. Therefore, the awareness of recycling used products is increasing not only in various industrial fields such as home appliances and automobiles where adhesive tapes are used, but also in the chemical industrial field where the adhesive tapes are manufactured. For the purpose of reducing such environmental loads, when recycling various products such as home appliances or automobiles, the used products are disassembled and the components in the products are removed. However, when removing the components, it is necessary to perform the operation of peeling off the adhesive tape for fixing the components and bonding the label. However, the adhesive tape is provided at various positions in the product, and it is desired to perform recycling more simply. As a technique of an adhesive tape for the purpose of recycling, for example, Patent Document 1 can be cited. In this Patent Document 1, a technique of an adhesive tape capable of directly recycling a polyethylene pipe in a state where an adhesive tape is pasted into a high-quality polyethylene polymer is disclosed. Prior Art Documents Patent Documents

[0004] Patent Document 1: Japanese Patent Application Laid-Open No. 2000-309759 Summary of the Invention Technical Problem to be Solved by the Invention

[0005] However, in Patent Document 1, as the characteristics of the recycled plastic material after recycling the polyethylene pipe with the adhesive tape pasted thereon, the tensile strength was studied, but it was not specifically disclosed how much tensile strength the recycled plastic material exhibited compared to the polyethylene pipe (polyethylene before recycling), and there remained a doubt as to whether the recycled plastic material could exhibit the desired characteristics. Therefore, an object of the present invention is to provide an adhesive tape that can be recycled in a state where it is pasted on an adherend having a thermoplastic resin, and the reduction rate of the tensile strength of the recycled plastic material after recycling in a state where the adhesive tape is pasted is small. Technical solution for solving technical problems

[0006] The inventors of the present invention conducted in-depth research to solve the above-mentioned technical problems of the prior art, and as a result, obtained the following insights: By making the thermoplastic resin contained in the adherend and an adhesive tape having a substrate and an adhesive layer laminated on at least one surface of the substrate satisfy a specific relational expression, an adhesive tape can be provided that can be recycled in a state of being adhered to an adherend having the thermoplastic resin, and the reduction rate of the tensile strength of the recycled recycled plastic material is small, thereby completing the invention of the present application. That is, the present invention is as follows.

[0007] [1] A recyclable adhesive tape, which is an adhesive tape having a substrate and an adhesive layer laminated on at least one surface of the substrate, The adhesive tape contains 5% by mass or more and 95% by mass or less of an olefin resin having an olefin monomer unit with respect to the total amount (100% by mass) of the adhesive tape, The adherend having the thermoplastic resin to which the adhesive tape is adhered and the adhesive tape satisfy the following relational expression (1). [Equation 1] 0.8 ≤ σ b / σ a ≤ 1.2 (1) (In the above relational expression (1), σ a is the tensile strength of the thermoplastic resin, and σ b is the tensile strength of a test piece produced by the thermoplastic resin in the adhesive tape and the adherend under the following conditions. <Production conditions of the test piece> After heating the mixture of the adhesive tape and the thermoplastic resin at the melting point of the thermoplastic resin + 20°C, resin pellets are produced using a twin-screw extruder under the conditions of a kneading speed of 350 rpm, a screw rotation speed of 300 rpm, and an extrusion speed of 5 kg / h, and then a multi-purpose test piece type A according to JIS K 7139 is produced using an injection molding machine and used as the test piece.)

[0008] [2] The recyclable adhesive tape according to [1], wherein the adherend having the thermoplastic resin to which the adhesive tape is adhered and the adhesive tape further satisfy the following relational expression (2). [Equation 2] 0.8 ≤ σ d / σ c ≤ 1.2 (2) (In the above relational expression (2), σ c is the flexural stress of the thermoplastic resin, σd is the bending stress of the test piece.)

[0009] [3] The recyclable adhesive tape according to [1] or [2], wherein the base material has the same resin as the thermoplastic resin or has a resin containing a partial chemical structure contained in the thermoplastic resin.

[0010] [4] The recyclable adhesive tape according to any one of [1] to [3], wherein the base material contains the olefin resin.

[0011] [5] The recyclable adhesive tape according to [4], wherein the olefin resin contains a polyethylene resin or a polypropylene resin.

[0012] [6] The recyclable adhesive tape according to any one of [1] to [5], wherein the base material is a foamed base material.

[0013] [7] The recyclable adhesive tape according to any one of [1] to [6], wherein the adhesive layer contains an acrylic adhesive.

[0014] [8] The recyclable adhesive tape according to any one of [1] to [7], wherein the thermoplastic resin contains an olefin resin.

[0015] [9] The recyclable adhesive tape according to [8], wherein the olefin resin contains a polyethylene resin or a polypropylene resin.

[0016]

[10] The recyclable adhesive tape according to any one of [1] to [9], wherein, relative to the total amount (100% by mass) of the mixture, the content of the adhesive tape contained in the mixture is 10% by mass or less.

[0017]

[11] The recyclable adhesive tape according to any one of [1] to

[10] , which contains one or more selected from an antioxidant, an ultraviolet absorber, a heat stabilizer, and a resin strengthening agent.

[0018]

[12] A component containing a thermoplastic resin to which the recyclable adhesive tape according to any one of [1] to

[11] is adhered.

[0019]

[13] An electronic device or a vehicle formed by using the component described in

[12] . Advantages of the Invention

[0020] According to the present invention, it is possible to provide an adhesive tape that can be recycled in a state of being adhered to an adherend having a thermoplastic resin, and the reduction rate of the tensile strength of the recycled plastic material in a state where this adhesive tape is adhered is small. Detailed implementation mode

[0021] Hereinafter, the implementation mode of the present invention (hereinafter referred to as "this implementation mode") will be described in detail, but the present invention is not limited to this implementation mode.

[0022] [Adhesive tape] The present invention is a recyclable adhesive tape, which is an adhesive tape having a base material and an adhesive layer laminated on at least one surface of the base material. The adhesive tape contains 5% by mass or more and 95% by mass or less of an olefin resin having olefin monomer units relative to the total amount (100% by mass) of the adhesive tape. The adherend having a thermoplastic resin to which the adhesive tape is adhered and the adhesive tape satisfy the following relational expression (1). [Formula 1] 0.8 ≤ σ b / σ a ≤ 1.2 (1) (In the above relational expression (1), σ a is the tensile strength of the thermoplastic resin, and σ b is the tensile strength of a test piece obtained by producing the thermoplastic resin in the adhesive tape and the adherend under the following conditions. <Production conditions of the test piece> After heating the mixture of the adhesive tape and the thermoplastic resin at the melting point of the thermoplastic resin + 20°C, resin pellets are produced using a twin-screw extruder under the conditions of a kneading speed of 350 rpm, a screw rotation speed of 300 rpm, and an extrusion speed of 5 kg / h. Then, using an injection molding machine, a multi-purpose test piece type A according to JIS K 7139 is produced and used as the test piece.) Thus, it is an adhesive tape that can be recycled in a state of being adhered to an adherend having a thermoplastic resin, and can exhibit the effect that the reduction rate of the tensile strength of the recycled plastic material after recycling the adhesive tape is small. It should be noted that "recycling" in this specification refers to the material recycling in the following three methods: (i) a method (material recycling) of recovering used products, products intended for disposal (e.g., pre-consumer), or discarded products and using them as raw materials (material: raw material); (ii) a method (thermal recycling) of incinerating waste with the premise of final disposal and using its combustion heat as energy; and (iii) a method (chemical recycling) of performing oilification, gasification, blast furnace reduction on waste plastics through thermal decomposition, etc. and then re-applying them. In addition, an extrusion molding machine for producing resin particles can use a known extrusion molding machine, preferably a twin-screw extrusion machine. Hereinafter, the main components and ingredients of the adhesive tape of this embodiment will be described, and then the base material and the adhesive layer constituting the adhesive tape will be described in detail.

[0023] (Structure of the adhesive tape) The adhesive tape of this embodiment includes a base material and an adhesive layer on at least one surface of the base material. The adhesive layer can exist in a manner of directly abutting against the base material, or the adhesive layer can be laminated on one surface of the base material with a known easy-bonding treatment layer interposed between the base material and the adhesive layer. In addition, since the adhesive layer is laminated on at least one surface of the base material, the adhesive layer can be laminated only on one surface of the base material, or the adhesive layer can be laminated on both surfaces of the base material. In the case of a double-sided adhesive design, the adhesive layers provided on each surface of the base material layer can be the same as each other, or can be different from each other. Furthermore, it can exist in a part of at least one surface of the base material in a manner of directly abutting against the base material, or can exist in the entire surface of at least one surface of the base material in a manner of the adhesive layer directly abutting against the base material. As a preferred mode of the adhesive tape of this embodiment, a double-sided adhesive design is a preferred structure.

[0024] (Main materials of the adhesive tape) The adhesive tape of this embodiment contains 5% by mass or more and 95% by mass or less of an olefin-based resin having an olefin-based monomer unit with respect to the total amount (100% by mass) of the adhesive tape. Thereby, the compatibility with an olefin-based resin material that is generally widely used as the adherend material of the adhesive tape can be ensured, so that recycling can be carried out in a state of being adhered to the adherend. From the viewpoints of the dimensional stability, mechanical strength of the base material layer of the adhesive tape, and the adhesive properties of the adhesive layer, it is preferred that the olefin-based resin is included in the material of the base material. The upper limit of the content of the olefin resin relative to the total amount (100% by mass) of the adhesive tape is preferably 95% by mass or less, 90% by mass or less, 80% by mass or less, 70% by mass or less, 65% by mass or less, or 60% by mass or less. On the other hand, the lower limit of the content of the olefin resin is preferably 5% by mass or more, 7% by mass or more, 10% by mass or more, 13% by mass or more, 15% by mass or more, or 17% by mass or more. Regarding the preferred range of the content of the olefin resin, the above upper and lower limit values can be appropriately combined. For example, it is preferably 5% by mass or more and 90% by mass or less, more preferably 10% by mass or more and 80% by mass or less, and still more preferably 15% by mass or more and 70% by mass or less. The upper limit value and the lower limit value of the content of the above olefin resin can be arbitrarily recombined. It should be noted that the calculation method of the content of the olefin resin relative to the total amount (100% by mass) of the adhesive tape is as described in the examples. In addition, as the olefin resin, from the viewpoint of obtaining a substrate, particularly a foamed substrate, having excellent flexibility, followability, and mechanical strength, it preferably contains a polyethylene resin and / or a polypropylene resin, and an ethylene-propylene copolymer resin. It should be noted that, as described later, in the adhesive tape of the present embodiment, it is preferable to use an olefin resin as the material of the substrate.

[0025] (Thermoplastic resin) The adhesive tape of the present embodiment can be adhered to an adherend having a thermoplastic resin. If the adherend containing a thermoplastic resin is the adhesion object of the adhesive tape of the present embodiment, the adherend containing a thermoplastic resin is easily melted by heat and can be easily remolded into a desired shape, so it is preferable from the viewpoint of material recycling. Examples of the thermoplastic resin include thermoplastic polyurethane (TPU); polycarbonate (PC) resin; vinyl chloride resins such as polyvinyl chloride (PVC) and vinyl chloride-vinyl acetate copolymer resins; acrylic resins such as polyacrylic acid, polymethacrylic acid, polymethyl acrylate, polymethyl methacrylate (PMMA), and polyethyl methacrylate; and polyethylene terephthalate (PET), polybutylene terephthalate, polytrimethylene terephthalate, polyethylene naphthalate, and polybutylene naphthalate. Ester resin; polystyrene resins such as polystyrene (PS), imide-modified polystyrene, acrylonitrile-butadiene-styrene (ABS) resin, imide-modified ABS resin, styrene-acrylonitrile copolymer (SAN) resin, acrylonitrile-(ethylene-propylene-diene)-styrene (AES) resin, polyethylene (PE) resin, polypropylene (PP) resin, cycloolefin resin, etc.; polyacetal (POM) resin; cellulose resins such as nitrocellulose and cellulose acetate; silicone resin; fluororesin, etc. It is preferred that the thermoplastic resin of the adherend to which the adhesive tape of the present embodiment is attached has a common chemical structure with the material constituting the adhesive tape, or has the same chemical structure as the main chain of the thermoplastic resin. As a result, the two are compatible, and the reduction rate of the tensile strength of the recycled plastic material as the material after the material is recycled becomes smaller. As the thermoplastic resin of this embodiment, olefin resins such as polyethylene (PE) resin, polypropylene (PP) resin, and cycloolefin resin are preferred, and polyethylene (PE) resin and polypropylene (PP) resin are more preferred. As a result, the material constituting the adhesive tape, especially the material of the base material, can be selected from olefin resins having excellent mechanical properties, so the reduction rate of the tensile strength of the recycled plastic material as the material after the material is recycled is smaller, which is preferred from the viewpoint of making it easy to use the recycled plastic material for the same purpose as before recycling.

[0026] (Adhesive) The adherend of the present embodiment is not particularly limited as long as it contains a thermoplastic resin, and examples thereof include adherends used in various industrial fields such as OA equipment, IT and home appliances, and automobiles, and the adherends are housings of these products, batteries, electronic components, structural components, and other components assembled in these products. Specifically, the adherends may be electrical and electronic equipment and components thereof, OA equipment and components thereof, information terminal equipment and components thereof, mechanical components, home appliances and components thereof, mobile bodies (aircraft, railway vehicles) and components thereof, vehicle components (automobile interior and exterior decoration), building components, various containers and components thereof, leisure goods and sundries and components thereof, or lighting equipment / components. In addition, the adherend can be fixed or temporarily fixed using the adhesive tape of the present embodiment. Further, for example, the adhesive tape of the present embodiment itself can also be a label that displays product information or the like. The adherend of the present embodiment only needs to satisfy the required performance of the adherend in terms of the content of the thermoplastic resin relative to the total amount of the adherend, and there is no particular limitation. However, from the perspective of recycling, it is preferably to contain more thermoplastic resin. Therefore, for example, it preferably contains 50% by mass or more, and preferably 60% by mass or more. It should be noted that the adherend of the present embodiment can be formed only of a thermoplastic resin.

[0027] (Relationship (1)) Regarding the adhesive tape of the present embodiment, the adherend having the thermoplastic resin to which the adhesive tape is adhered and the adhesive tape satisfy the following relationship (1). [Equation 1] 0.8 ≤ σ b / σ a ≤ 1.2 (1) (In the above relationship (1), σ a is the tensile strength (MPa) of the thermoplastic resin, and σ b is the tensile strength (MPa) of the test piece made of the thermoplastic resin in the adhesive tape and the adherend under the following conditions. <Manufacturing conditions of the test piece> After heating the mixture of the adhesive tape and the thermoplastic resin at the melting point of the thermoplastic resin + 20°C, resin pellets are produced using a twin-screw extruder under the conditions of a kneading speed of 350 rpm, a screw rotation speed of 300 rpm, and an extrusion speed of 5 kg / h. Then, using an injection molding machine, a multi-purpose test piece type A according to JIS K 7139 is produced and used as the test piece.) Thus, it is possible to provide an adhesive tape with a small reduction rate of the tensile strength of the recycled plastic material after recycling and excellent material recyclability. σ b represents the tensile strength of the resin material regenerated from the mixture of the adhesive tape and the thermoplastic resin (σ a ), and the ratio of the tensile strength of the thermoplastic resin (σ b ) of the material of the adherend that is the adhesive tape is σ aIn the range of 0.8 to 1.2 means that the mechanical properties of the thermoplastic resin as the material before kneading and melting ( = before recycling) and the alloy resin of the adhesive tape and the thermoplastic resin as the material after kneading and melting ( = after recycling) are similar (within ±20%). More specifically, the tensile strength refers to the maximum stress that the material can withstand in a series of processes from elastic deformation to plastic deformation to fracture. Based on this, the state where the tensile strengths of the two resins are similar means that the adhesive tape and the thermoplastic resin are compatible with each other in the recycled alloy resin. Therefore, if a morphological explanation is given for the alloy resin of the adhesive tape and the thermoplastic resin as the material after recycling, it is considered that in this alloy resin, the components from the so-called adhesive tape and the components from the so-called thermoplastic resin are compatible, and thus exhibit the same tensile strength as the thermoplastic resin as the material before kneading and melting ( = before recycling). Thus, it is considered to have the effect of a small reduction rate of the tensile strength of the recycled plastic material after recycling. Represents the tensile strength (σ b ) of the resin material regenerated from the mixture of the adhesive tape and the thermoplastic resin a ) with respect to the tensile strength (σ b ) of the thermoplastic resin as the adherend material of the adhesive tape a The ratio of σ

[0028] The content of the adhesive tape contained in the mixture of the adhesive tape and the thermoplastic resin can be arbitrarily set according to the usage. For example, it is preferably 10% by mass or less with respect to the total amount of the mixture. When this content is 10% by mass or less, the proportion of the thermoplastic resin in the recycled resin is high, so the recycled resin is easily used as a single raw material. In addition, the upper limit of the content of the adhesive tape contained in the mixture is preferably 9.5% by mass or less, 7.5% by mass or less, 6.5% by mass or less, 5.3% by mass or less, 4.1% by mass or less, or 3.5% by mass or less. On the other hand, the lower limit of the content of the adhesive tape contained in the mixture is preferably greater than 0% by mass, 0.013% by mass or more, 0.1% by mass or more, 0.3% by mass or more, 0.8% by mass or more, or 1% by mass or more. When the content of the adhesive tape contained in the mixture of the adhesive tape and the thermoplastic resin is in the above range, the tensile strength (σ b ) of the resin material regenerated from the mixture of the adhesive tape and the thermoplastic resin a ) with respect to the tensile strength (σb / σ a This is the preferred range of the present invention and is preferred from the viewpoint of suppressing the deterioration of physical properties after recycling.

[0029] The method for measuring the tensile strength (MPa) of the thermoplastic resin and the tensile strength (MPa) of the test piece obtained from the mixture of the adhesive tape and the thermoplastic resin is as described in the following examples. According to JIS K7161-1, using a tensile testing machine (manufactured by Shimadzu Corporation), the measurement is carried out under the measurement conditions of a clamping jig distance of 115 mm, a gauge length of 75 mm, a test speed of 50 mm / min, and 23°C and 50% RH.

[0030] (Relationship (2)) Regarding the adhesive tape of the present embodiment, it is further preferred that the adherend having the thermoplastic resin to which the adhesive tape is adhered and the adhesive tape satisfy the following relationship (2). [Equation 2] 0.8 ≤ σ d / σ c ≤ 1.2 (2) (In the above relationship (2), σ c is the flexural strength (MPa) of the thermoplastic resin, and σ d is the flexural strength (MPa) of the test piece.) Thereby, it is possible to provide an adhesive tape with a smaller reduction rate of the tensile strength of the recycled plastic material after recycling and excellent material recyclability. σ d represents the ratio of the flexural strength (σ c ) of the resin material regenerated from the mixture of the adhesive tape and the thermoplastic resin to the flexural strength (σ d ) of the thermoplastic resin as the adherend material of the adhesive tape. The range of σ d / σ c being in the range of 0.8 to 1.2 means that, similar to the above tensile strength, the mechanical properties of the thermoplastic resin as the material before kneading and melting (= before recycling) and the blend resin of the adhesive tape and the thermoplastic resin as the material after kneading and melting (= after recycling) are approximated (within ±20%), and thus it shows a state where the adhesive tape and the thermoplastic resin are compatible with each other in the blend resin after recycling. Therefore, if the morphology of the blend resin of the adhesive tape and the thermoplastic resin as the material after recycling is described, it is considered that in this blend resin, the component from the so-called adhesive tape and the component from the so-called thermoplastic resin are compatible, and thus it shows a flexural strength equivalent to that of the thermoplastic resin as the material before kneading and melting (= before recycling). Thereby, it is considered to have the effect of a small reduction rate of the flexural strength of the recycled plastic material after recycling. Indicates the flexural strength (σ d ) of the resin material regenerated from the mixture of the adhesive tape and the thermoplastic resin relative to the flexural strength (σ c ) of the thermoplastic resin that is the adherend of the adhesive tape, and the ratio of σ d / σ c is preferably in the range of 0.88 to 1.16, more preferably in the range of 0.92 to 1.1. When calculating the above-mentioned relational expression (2), the content of the adhesive tape contained in the mixture of the adhesive tape and the thermoplastic resin can be arbitrarily set according to the usage mode. For example, it is preferable that the content of the adhesive tape contained in the mixture of the adhesive tape and the thermoplastic resin is 10% by mass or less relative to the total amount of the mixture. When the content is 10% by mass or less, the proportion of the thermoplastic resin in the recycled resin is high, so the recycled resin is easily used as a single raw material. In addition, the upper limit of the content of the adhesive tape contained in the mixture is preferably 9.5% by mass or less, 7.5% by mass or less, 6.5% by mass or less, 5.3% by mass or less, 4.1% by mass or less, or 3.5% by mass or less. On the other hand, the lower limit of the content of the adhesive tape contained in the mixture is preferably greater than 0% by mass, 0.013% by mass or more, 0.1% by mass or more, 0.3% by mass or more, 0.8% by mass or more, or 1% by mass or more. When the content of the adhesive tape contained in the mixture of the adhesive tape and the thermoplastic resin is within the above range, the flexural strength (σ d ) of the resin material regenerated from the mixture of the adhesive tape and the thermoplastic resin relative to the flexural strength (σ c ) of the thermoplastic resin that is the adherend of the adhesive tape, and the ratio of σ d / σ c is within the preferred range of the present invention and is preferable from the viewpoint of suppressing the reduction of physical properties after recycling.

[0031] The method for measuring the flexural strength (MPa) of the thermoplastic resin and the flexural strength (MPa) of the test piece obtained from the mixture of the adhesive tape and the thermoplastic resin is as described in the following examples. Using a tensile testing machine (manufactured by Shimadzu Corporation), according to JIS K7171, a three-point bending test is performed under the measurement conditions of a test speed of 2 mm / minute, a lower support distance of 64 mm, and 23°C and 50% RH to measure the flexural strength (maximum flexural stress, MPa) and the flexural strain (%) of the flexural strength.

[0032] In the present embodiment, as the requirements showing a tendency to easily satisfy the above-mentioned relational expression (1), the following (I-1) to (IX-1) can be cited. (I-1) Preferably, the base material or the adhesive layer of the adhesive tape has the same resin as the thermoplastic resin, or has a resin containing a partial chemical structure contained in the thermoplastic resin. Among them, it is further preferred that the base material has the same resin as the thermoplastic resin, or has a resin containing a partial chemical structure contained in the thermoplastic resin. (II-1) Preferably, the base material or the adhesive layer of the adhesive tape is an olefin resin such as polyethylene (PE) resin, polypropylene (PP) resin, cycloolefin resin, or has these resins. Among them, polyethylene (PE) resin and polypropylene (PP) resin are more preferred. (III-1) Preferably, the base material constituting the adhesive tape is an olefin resin such as polyethylene (PE) resin, polypropylene (PP) resin, cycloolefin resin, or has these resins. Among them, polyethylene (PE) resin, polypropylene (PP) resin, and ethylene-propylene copolymer resin are more preferred. (IV-1) Preferably, the thermoplastic resin is an olefin resin such as polyethylene (PE) resin, polypropylene (PP) resin, cycloolefin resin, and polyethylene (PE) resin and polypropylene (PP) resin are more preferred. (V-1) Preferably, the weight average molecular weight of the adhesive composition constituting the adhesive layer of the adhesive tape is 400,000 to 1,600,000. (VI-1) Preferably, the adhesive layer of the adhesive tape contains a rosin resin, a polymerized rosin resin, a polymerized rosin ester resin, a rosin phenol resin, a stabilized rosin ester resin, a disproportionated rosin ester resin, a hydrogenated rosin ester resin, a terpene resin, a terpene phenol resin, a petroleum resin, and a (meth)acrylate resin. (VII-1) Preferably, the adhesive layer of the adhesive tape is formed by using an acrylic adhesive composition or a rubber-based adhesive composition. (VIII-1) Preferably, with respect to the total amount (100% by mass) of the adhesive tape, the content of the olefin resin is 5% by mass or more and 90% by mass or less. (IX-1) Preferably, with respect to the total mass of the mixture of the adhesive tape and the thermoplastic resin, the proportion of the adhesive tape is 10% by mass or less. By satisfying the above conditions (I-1) to (IX-1), the compatibility between the thermoplastic resin and the adhesive tape is improved. Furthermore, since the mixture of the adhesive tape and the thermoplastic resin has the same crystallinity (molecular orientation) and intermolecular interaction as the thermoplastic resin, the tensile strength (σ b ) of the resin material regenerated from the mixture of the adhesive tape and the thermoplastic resin relative to the tensile strength (σ a ) of the thermoplastic resin as the adherend material of the adhesive tape, the ratio of σb / σ a This is the preferred range of the present invention and is preferred from the viewpoint of suppressing the deterioration of physical properties after recycling.

[0033] Similarly, in the present embodiment, as the requirements for showing a tendency to easily satisfy the above relational expression (2), the following (I-2) to (IX-2) can be cited. (I-2) Preferably, the base material or the adhesive layer of the adhesive tape has the same resin as the thermoplastic resin, or has a resin containing a partial chemical structure contained in the thermoplastic resin. Among them, it is further preferred that the base material has the same resin as the thermoplastic resin, or has a resin containing a partial chemical structure contained in the thermoplastic resin. (II-2) Preferably, the base material or the adhesive layer of the adhesive tape is an olefin resin such as a polyethylene (PE) resin, a polypropylene (PP) resin, or a cycloolefin resin, or has these resins. Among them, polyethylene (PE) resin, polypropylene (PP) resin, and ethylene-propylene copolymer resin are more preferred. (III-2) Preferably, the base material constituting the adhesive tape is an olefin resin such as a polyethylene (PE) resin, a polypropylene (PP) resin, or a cycloolefin resin, or has these resins. Among them, polyethylene (PE) resin, polypropylene (PP) resin, and ethylene-propylene copolymer resin are more preferred. (IV-2) Preferably, the thermoplastic resin is an olefin resin such as a polyethylene (PE) resin, a polypropylene (PP) resin, or a cycloolefin resin, and polyethylene (PE) resin and polypropylene (PP) resin are more preferred. (V-2) Preferably, the weight-average molecular weight of the adhesive composition of the adhesive layer constituting the adhesive tape is 400,000 to 1,600,000. (VI-2) Preferably, the adhesive layer of the adhesive tape contains a rosin resin, a polymerized rosin resin, a polymerized rosin ester resin, a rosin phenol resin, a stabilized rosin ester resin, a disproportionated rosin ester resin, a hydrogenated rosin ester resin, a terpene resin, a terpene phenol resin, a petroleum resin, and a (meth)acrylate resin. (VII-2) Preferably, the adhesive layer of the adhesive tape is formed by using an acrylic adhesive composition or a rubber-based adhesive composition. (VIII-2) Preferably, the content of the olefin resin is 5% by mass or more and 90% by mass or less with respect to the total amount (100% by mass) of the adhesive tape. (IX-2) Preferably, the proportion of the adhesive tape is 10% by mass or less with respect to the total mass of the mixture of the adhesive tape and the thermoplastic resin. By satisfying the conditions of the above (I-2) to (IX-2), the compatibility between the thermoplastic resin and the adhesive tape is improved. Further, since the mixture of the adhesive tape and the thermoplastic resin has the same crystallinity (molecular orientation) and intermolecular interaction as the thermoplastic resin, the flexural strength (σ d ) of the resin material regenerated from the mixture of the adhesive tape and the thermoplastic resin with respect to the flexural strength (σ c ) of the thermoplastic resin which is the adherend material of the adhesive tape, the ratio of σ d / σ c is within the preferred range of the present invention and is preferred from the viewpoint of suppressing the reduction of physical properties after recycling.

[0034] The adhesive tape of the present embodiment is preferably made from biomass raw materials. Specifically, in the present embodiment, the lower limit of the biomass carbon content rate (%) of the adhesive tape is preferably 10% or more, 13% or more, 15% or more, 17% or more, 20% or more, 25% or more, 35% or more in turn with respect to all carbon atoms in the adhesive tape. On the other hand, the upper limit of the biomass carbon content rate (%) is preferably 100% or less, 90% or less, 80% or less, 73% or less, 68% or less in turn. The upper limit and the lower limit can be arbitrarily combined. For example, the range of the biomass carbon content rate (%) of the adhesive tape is preferably 10% or more, more preferably 10% or more and 90% or less, further preferably 20% or more and 80% or less, further preferably 22% or more and 73% or less. When the biomass carbon content rate (%) of the adhesive tape is 10% or more, the effect of reducing the environmental load can be exerted. The "biomass carbon content rate (%)" in this specification is a corrected value obtained by multiplying the content ratio (pMC%) of radiocarbon ( 14 C) by 0.93 as a correction ratio, and when the corrected value is 100% or more, it is regarded as 100%.

[0035] The thermoplastic resin in the adherend of the present embodiment is preferably made from biomass raw materials. Specifically, in the present embodiment, the lower limit of the biomass carbon content rate (%) of the thermoplastic resin is preferably 10% or more, 13% or more, 15% or more, 17% or more, 20% or more, 25% or more, 35% or more in turn with respect to all carbon atoms in the adhesive tape. On the other hand, the upper limit of the biomass carbon content rate (%) is preferably 100% or less, 90% or less, 80% or less, 73% or less, 68% or less in turn.

[0036] In order for the biomass carbon content rate (%) of the adhesive tape of the present embodiment to be within a specified range, for example, it can be achieved by using materials derived from biomass for the material of the base material and / or any component of the adhesive layer (adhesive composition). For example, as the material of the base material, it is preferable to use an olefin-based monomer unit (e.g., ethylene) as the biomass raw material. For example, as an example of using ethylene as the biomass raw material, ethylene derived from the biomass raw material can be synthesized by the following biosynthetic pathways (1) to (3) or by a well-known method using bioethanol. In addition, polypropylene can be synthesized from this ethylene by a well-known method. (Refer to C.W. Ingram, R.J. Lancashire, Cata.lett., 31, 395 (1995), etc.). [Chemical formula 1] (1) L-Met → SAM → ACC → ethylene (plant) (2) L-Met → KMBA → ethylene (microorganism) (3) L-Glu → AKG → ethylene (microorganism) L-Met: methionine, SAM: S-adenosylmethionine, ACC: aminocyclopropane carboxylic acid, KMBA: 2-keto-4-methylthiobutyric acid, AKG: α-ketoglutaric acid, L-Glu: glutamic acid.

[0037] The content ratio (pMC%) of radiocarbon ( 14 C) in this specification represents the carbon concentration (mass ratio) of the component derived from biomass and is related to the so-called blending ratio of biomass. More specifically, it is the value of the content ratio of radiocarbon ( 14 C) obtained by the radiocarbon ( 14 C) measurement method according to ASTM-D6866 (especially ASTM D6866 Method B). It is known that radiocarbon ( 14 C) has the property of radiatively decaying into nitrogen ( 14 N) with a half-life of 5730 years. Moreover, on the earth, due to the action of cosmic rays irradiated from the universe, an extremely small amount of radiocarbon ( 14 C) is continuously generated, oxidized into carbon dioxide 14 CO2 and diffused in the atmosphere, then ingested into animals and plants during the process of the food chain, and disappears according to the half-life while circulating in the environment through this food chain. Therefore, the radiocarbon ( 14 C) measurement method utilizes the fact that fossil fuels substantially do not contain radiocarbon ( 14C), and in the case of radiocarbon in the atmosphere during the carbon absorption growth period from biomass (or organisms) 14 C), according to the ratio of radiocarbon 14 C) in the carbon contained in the biomass material (or organism) to estimate the content ratio (pMC%) of radiocarbon 14 C). Therefore, the larger the value of the content ratio (pMC%) of radiocarbon 14 C), the less the amount of fossil fuel used, and the more effective it is in reducing the environmental load. Therefore, the value of the content ratio (pMC%) of radiocarbon 14 C) is related to an index representing the blending ratio of biomass, which is a renewable organic resource from organisms ( = biomass carbon content rate (%)).

[0038] By measuring the proportion of radiocarbon 14 C) contained in all carbon atoms of the thermoplastic resin in the adhesive tape or the adherend of this embodiment, the proportion of carbon from biomass can be calculated. In the present invention, after making graphite for measurement from the adhesive tape or the thermoplastic resin by a known method, accelerator mass spectrometry (AMS) is performed, and the content ratio (pMC%) of radiocarbon 14 C) in the adhesive tape or the adherend is calculated by the following formula (X). Then, according to the following formula (Y), the value of the content ratio (pMC%) of this radiocarbon 14 C) is multiplied by 0.93, and the value considering the influence of atmospheric nuclear tests from 1950 to the present is used as the biomass carbon content rate (%) of the adhesive tape or the adherend. Formula (X): Content ratio (pMC%) of radiocarbon 14 C) = [{Radiocarbon of the thermoplastic resin in the adhesive tape or the adherend 14 C) ÷ Carbon contained in the thermoplastic resin in the adhesive tape or the adherend 12 C)} / {Radiocarbon of the reference material 14 C) / Carbon of the reference material 12 C)} × 100 (In the above formula (X), for the reference material, a substance obtained by converting oxalic acid (SRM4990C), which is a reference material for radiocarbon dating supplied by the National Institute of Standards and Technology of the United States, into graphite by the same pretreatment method as the graphite for measurement described in the Examples section below, is used.) Formula (Y): Biomass carbon content rate (%) = Content ratio (pMC%) of radiocarbon 14 C) × 0.93

[0039] It should be noted that due to the influence of atmospheric nuclear tests after 1950, the radiocarbon ( 14 C) artificially injected into the atmosphere has been observed to have approximately 1.5 times the normal amount of radiocarbon ( 14 C). However, it gradually decreases over time, and the current value is around 107.5 (pMC%). Therefore, in the present invention, similar to the standard of ASTM D6866, the value obtained by multiplying the content ratio (pMC%) of radiocarbon ( 14 C) by 0.93 (= 100 / 107.5) is defined as the biomass carbon content rate (%). However, even when using the method using the above formula (Y), values above 100% may be calculated. Therefore, in the present invention, similar to the ASTM standard, when the value of the biomass carbon content rate (%) is 100% or more, it is regarded as 100%.

[0040] In the present embodiment, for the determination of the concentration of radiocarbon ( 14 C), by means of accelerator mass spectrometry (AMS: Accelerator Mass Spectrometry) combining a tandem accelerator and a mass spectrometer, the isotopes of carbon atoms contained in the sample to be analyzed are physically separated by the accelerator using the weight difference of atoms (specifically, 12 C, 13 C, 14 C), and the method of measuring the abundance of atoms of each isotope is used for determination. In addition, for the sample to be described in the analysis, which is a thermoplastic resin in an adhesive tape or an adherend, pretreatment is required. Specifically, the carbon contained in the sample is oxidized and completely converted into carbon dioxide. Further, the obtained carbon dioxide is separated from water and nitrogen, and the carbon dioxide is subjected to reduction treatment and converted into graphite as solid carbon. The obtained graphite is used as the sample for measurement. The accelerator mass spectrometry of the present embodiment adopts the following method: irradiating the sample with cations such as Cs + to generate negative carbon ions, accelerating the carbon ions using a 3MV tandem accelerator, performing charge conversion of the negative ions to positive ions, and separating the traveling orbits of 12 C 3+ 、 13 C 3+ 、 14 C 3+ by a mass spectrometry electromagnet, 14 C 3+ and measuring through an electrostatic analyzer. It should be noted that the carbon isotopes 12 C, 13 C, and 14C accelerates at the same speed, the magnetic field of the electromagnet for mass spectrometry is analyzed, and the flying wires are bent. At this time, 12 C, 13 C flies on the inner side, and the heaviest 14 C flies on the outermost side of the bent portion. In addition, 12 C, 13 Since there are a large number of C, it passes through the Faraday cup detector as an electric current, 14 C passes through the ionization box-shaped ion detector and is counted one by one.

[0041] Hereinafter, the base material and the adhesive layer constituting the adhesive tape will be described. (Base material) The adhesive tape of the present embodiment has a base material as a carrier of the adhesive layer. In addition, in the case of a double-sided adhesive tape having adhesive layers on both sides of the base material, the base material functions as a core.

[0042] The base material of the present embodiment is not particularly limited, and examples thereof include a resin base material, a foam base material, a non-woven fabric, a rubber sheet, a woven fabric, paper, glass, a metal foil, a composite thereof, and the like. The resin base material is a non-foamed or non-porous resin film or sheet, which is distinguished from a non-woven fabric or a foam base material. Among them, from the viewpoints of emphasizing high adhesiveness between the adhesive layer and the base material, being able to be easily colored, easily showing the shielding property and designability due to the color of the base material, the base material is preferably a resin base material. On the other hand, from the aspect of emphasizing excellent adhesion to the adherend and being particularly suitable for following the adherend having an uneven shape or a rough surface and having excellent adhesion, the base material is preferably a foam base material. The base material of the present embodiment preferably has the same resin as the thermoplastic resin contained in the adherend, or a resin containing a partial chemical structure contained in the thermoplastic resin. Thereby, an adhesive tape can be provided which can be recycled in a state of being adhered to an adherend having a thermoplastic resin, and the reduction rate of the tensile strength of the recycled plastic material of the adhesive tape is smaller.

[0043] The base material may be colorless (so-called colorless base material) or colored (so-called colored base material). The colored base material can be formed, for example, by providing a colored layer on the surface of a resin film or the like by printing or coating, or by making the resin material constituting the resin film or the like contain a colorant.

[0044] For the purpose of improving the adhesion to the adhesive layer, the substrate may have a primer layer on the surface or may be surface-treated. Examples of the surface treatment include roughening treatment using a sandblasting method, a solvent treatment method, etc., corona discharge treatment, atmospheric pressure plasma treatment, chromic acid treatment, flame treatment, hot air treatment, ozone-ultraviolet irradiation treatment, oxidation treatment, anchor coating treatment, etc. In addition, an antistatic treatment may be applied to the surface of the substrate.

[0045] <Resin Substrate> As the resin substrate of the present embodiment, for example, a sheet or film obtained by using a polyester resin such as polyester, polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, an olefin resin (polyethylene resin, polypropylene resin), polyacrylate, polyvinyl chloride, polypropylene ethylene vinyl alcohol, polyurethane resin, polyamide resin, polyimide resin, etc. can be used. As the said resin substrate, a resin substrate which has been subjected to corona treatment, anchor coating treatment, etc. can be used in terms of improving the anchoring property of the said adhesive layer. When the substrate in the present embodiment is a resin substrate, an olefin resin (polyethylene resin, polypropylene resin, ethylene-propylene copolymer resin) is preferred.

[0046] The average thickness of the resin substrate of the present embodiment can be appropriately set according to the use of the adhesive tape. It is preferably 1 μm to 150 μm, more preferably 2 μm to 120 μm, and further preferably 3 μm to 100 μm. By making the thickness of the said substrate within the above range, the adhesive tape easily follows the strain of the adherend and it is easy to obtain high adhesive strength, so it is preferred. As the said resin substrate, in order to further improve the adhesion to the adhesive layer, a substrate provided with a primer layer, a substrate which has been subjected to surface roughening treatment based on a sandblasting method, a solvent treatment method, etc., corona discharge treatment, chromic acid treatment, flame treatment, hot air treatment, ozone treatment, ultraviolet irradiation treatment, oxidation treatment, etc. can be used.

[0047] As a manufacturing method of the resin substrate of the present embodiment, there are a casting method based on extrusion molding, a uniaxial stretching method, a sequential biaxial stretching method, a simultaneous biaxial stretching method, a blow molding method, a tube method, and also a calendering method, a solution method, etc. Among them, a manufacturing method using a casting method based on extrusion molding, a uniaxial stretching method, a sequential biaxial stretching method, a simultaneous biaxial stretching method, a blow molding method, a tube method can be appropriately used, and it can be selected according to the mechanical strength required for the resin substrate of the present embodiment.

[0048] The said resin substrate may have a single-layer structure, a two-layer, three-layer or more multi-layer structure. In the case of a multi-layer structure, it is preferred that at least one layer is a layer having the said resin composition, as it easily exhibits the necessary mechanical properties.

[0049] <Foamed substrate> The substrate of this embodiment is preferably a foamed substrate. Thereby, it has excellent adhesion to the adherend, and is particularly suitable for following adherends with uneven shapes or rough surfaces and has excellent adhesion. It is preferable that the foamed structure of the foamed substrate of the embodiment is a closed-cell structure, which can effectively prevent water from soaking in from the cut surface of the foamed substrate. The shape of the closed cells forming the closed-cell structure is not particularly limited. Closed cells having a shape with an average cell diameter in the flow direction, width direction, or both directions longer than the average cell diameter in the thickness direction of the foam have appropriate cushioning properties, so they are preferable.

[0050] The average cell diameter in the thickness direction of the foamed substrate of this embodiment is preferably in the range of 1 μm to 150 μm, more preferably in the range of 5 μm to 100 μm, and further preferably in the range of 10 μm to 60 μm. The average cell diameter in the flow direction and width direction of the foamed substrate is 1.2 μm to 700 μm, preferably 10 μm to 500 μm, more preferably 50 μm to 300 μm, and further preferably 50 μm to 160 μm. By making the average cell diameter in this range, it is easy to form closed cells even when the width of the double-sided tape is narrow, and it is possible to appropriately cut off the water infiltration path starting from the cross-section of the foamed substrate.

[0051] In the foamed substrate of this embodiment, the ratio of the average cell diameter is not particularly limited. The ratio of the average cell diameter in the flow direction of the foamed substrate to the average cell diameter in the thickness direction of the foamed substrate (average cell diameter in the flow direction / average cell diameter in the thickness direction) is preferably 1.2 to 15, more preferably 3 to 8. In addition, the ratio of the average cell diameter in the width direction of the foamed substrate to the average cell diameter in the thickness direction of the foamed substrate (average cell diameter in the width direction / average cell diameter in the thickness direction) is preferably 1.2 to 15, more preferably 3 to 8. In addition, it is further preferred that both the flow direction and the width direction are within the above ratio range. When this ratio is 1.2 or more, it is easy to ensure flexibility in the thickness direction, so the followability is improved. In addition, when it is 15 times or less, fluctuations in the flexibility and tensile strength in the flow direction and width direction of the foamed substrate are less likely to occur.

[0052] Furthermore, regarding the ratio of the average cell diameter in the flow direction to the average cell diameter in the width direction, when the flow direction is set to 1, it is preferably 0.25 times to 4 times, more preferably 0.33 times to 3 times. When within the above ratio range, fluctuations in the flexibility and tensile strength in the flow direction and width direction of the foamed substrate are less likely to occur.

[0053] It should be noted that the average bubble diameter in the width direction, flow direction, and thickness direction of the foam base material is measured according to the following points. First, the foam base material is cut into a size of 1 cm in the width direction and 1 cm in the flow direction.

[0054] Next, a digital microscope (trade name "KH-7700", manufactured by HiROX Corporation) is set to a magnification of 200 times, and the cut surface in the width direction or flow direction of the foam base material is observed. At this time, the entire length in the thickness direction of the cut surface of the foam base material is observed. In the above observation, the bubble diameters of all the bubbles present within a range of 2 mm in the flow direction or width direction of the cut surface are measured. Then, the range of 2 mm is changed, and the bubble diameters of all the bubbles present within any 10 ranges are measured.

[0055] Calculate the average value of the bubble diameters obtained from the above measurements, and use the value thus obtained as the average bubble diameter.

[0056] As the foam base material, for example, a foam base material having a 25% compressive strength of 20 kPa or more is preferably used, a foam base material having a 25% compressive strength of 30 kPa to 1500 kPa is more preferably used, and a foam base material having a 25% compressive strength of 50 kPa to 1000 kPa is further preferably used in terms of exhibiting appropriate adhesive strength to an adherend having an uneven shape or a rough surface. It should be noted that the 25% compressive strength is measured in accordance with JIS K6767. Specimens cut into 25 mm squares are stacked to a thickness of about 10 mm. The specimens are clamped with a stainless steel plate larger in area than the specimens, and the strength is measured when the specimens are compressed by about 2.5 mm (25% of the original thickness) at a speed of 10 mm / minute at 23°C.

[0057] The tensile strength in the flow direction and width direction of the foam base material is not particularly limited, and is preferably 500 N / cm 2 or more, more preferably 600 N / cm 2 to 1800 N / cm 2 . In addition, the tensile strength in the direction with the lower tensile strength among the flow direction and width direction is preferably 500 N / cm 2 to 1400 N / cm 2 , more preferably 600 N / cm 2 to 1200 N / cm 2 . At this time, the tensile strength in the higher direction is preferably 700 N / cm 2 to 1800 N / cm 2 , more preferably 800 N / cm 2 to 1600 N / cm 2In addition, the tensile elongation at break in the tensile test is not particularly limited. The tensile elongation in the flow direction is preferably 200% to 1500%, more preferably 400% to 1000%, still more preferably 620% to 950%, and particularly preferably 450% to 800%. Since the foamed base material has a tensile strength and a tensile elongation within this range, even if it is a soft foamed base material, deterioration of the processability of the adhesive tape and reduction of the sticking workability can be suppressed. In addition, when peeling the adhesive tape, interlayer breakage and tearing of the foamed base material are not likely to occur, and even in the case of interlayer breakage, easy peelability of the adhesive tape can be imparted.

[0058] It should be noted that the tensile strength in the flow direction and the width direction of the foamed base material is measured according to JIS K6767. It is the maximum strength obtained by measuring a sample with a marked length of 2 cm and a width of 1 cm under the measurement conditions of a tensile speed of 300 mm / min in an environment of 23°C and 50% RH using a Tensilon tensile testing machine.

[0059] The apparent density of the foamed base material is not particularly limited. From the aspect of adjusting the interlayer strength, compressive strength, average bubble diameter, etc. to the above ranges and easily achieving both impact resistance and excellent adhesion to the adherend, it is 0.08 g / cm 3 ~0.8 g / cm 3 Preferably it is 0.1 g / cm 3 ~0.7 g / cm 3 More preferably it is 0.15 g / cm 3 ~0.65 g / cm 3 It should be noted that the apparent density is measured according to JIS K6767. Prepare a foamed base material cut into a rectangle of 4 cm × 5 cm with a length of about 15 cm 3 , measure its mass, and calculate the apparent density.

[0060] As the foamed base material, a base material with a thickness of 1500 μm or less is preferably used, a base material with a thickness of 1300 μm or less is more preferably used, and a base material with a thickness of 700 μm or less is more preferably used in terms of imparting excellent processability of the tape and excellent followability to the adherend. The lower limit of the thickness is preferably 50 μm. In addition, the foamed base material may have other layers as needed. As the other layers, for example, in terms of imparting dimensional stability, good tensile strength, reprocessing adaptability, etc. to the adhesive tape, there can be mentioned laminated layers such as polyester films and polyolefin films, conductive layers such as light-shielding layers, light-reflecting layers, and metal layers, and heat-conducting layers.

[0061] In this embodiment, the compression strength or tensile strength of the foam base material can be appropriately adjusted according to the raw materials of the base material used or the foam structure. There is no particular limitation on the type of the foam base material of this embodiment, and olefin resin foams such as polyethylene, polypropylene, ethylene-propylene copolymer resin, ethylene-vinyl acetate copolymer, etc. can be used; polyurethane foams; rubber foams containing acrylic rubber or other elastomers, etc. Among them, from the viewpoints of easily manufacturing a thin foam base material with excellent followability to the unevenness of the adherend surface, cushioning absorption properties, etc., and easy recyclability of the olefin resin of the adherend which is mostly used as a thermoplastic resin, olefin resin foams can be preferably used. The olefin resin is a resin having olefin monomer units and can be manufactured by polymerization of olefin monomers. Examples of the preferred olefin monomers include: ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 3-methyl-1-butene, 3-methyl-1-pentene, 3-ethyl-1-pentene, 4-methyl-1-pentene, 4-methyl-1-hexene, 4,4-dimethyl-1-hexene, 4,4-dimethyl-1-pentene, 4-ethyl-1-hexene, 3-ethyl-1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, 1-eicosene, or their derivatives, etc. Among them, from the viewpoints of productivity and cost, ethylene or propylene can be particularly preferably used. Therefore, it is preferred that the base material contains an olefin resin. In addition, the olefin resin preferably contains a polyethylene resin or an ethylene-propylene copolymer resin. It should be noted that the olefin resin can be used alone or in combination of two or more.

[0062] When the foam base material contains an olefin resin, its content is preferably 70% by mass or more and 99% by mass or less, more preferably 80% by mass or more and 98% by mass or less, further preferably 90% by mass or more and 98% by mass or less, based on the total amount (100% by mass) of the foam base material.

[0063] Examples of such a foam base material include crosslinked olefin resin foams, which are obtained by supplying an olefin resin and a thermally decomposable foaming agent to an extruder for melt-kneading, and then subjecting the foaming olefin resin sheet formed by extruding from the extruder into a sheet shape to electron beam crosslinking and then foaming, stretching, and thinning. As the olefin resin, conventionally known olefin resins can be used, and preferably contain 40% by mass or more of a polyethylene resin obtained using a metallocene compound containing a tetravalent transition metal. In addition, after foaming the foam, the foamed sheet can be sliced in the thickness direction and then stretched and skinned using a hot roll.

[0064] In order to improve the adhesion to the adhesive layer or other layers, the foam substrate can be subjected to surface treatments such as corona treatment, flame treatment, plasma treatment, hot air treatment, ozone-ultraviolet treatment, and coating with an adhesion promoter. The surface treatment makes the wetting index based on the wetting reagent 36 mN / m or more, preferably 40 mN / m or more, thereby obtaining good adhesion to the adhesive.

[0065] <Other components> In addition, in the present embodiment, the foam substrate can be a foam substrate that contains the following substances as needed within a range that does not impair the properties: other polymer components, crosslinking agents, anti-aging agents, ultraviolet absorbers, fillers, polymerization inhibitors, surface modifiers, antistatic agents, defoaming agents, viscosity regulators, light stabilizers, weather stabilizers, heat stabilizers, antioxidants, leveling agents, organic pigments, inorganic pigments, pigment dispersants, resin reinforcing agents such as silica beads, organic beads, and cellulose nanofibers; inorganic fillers such as silica, alumina, titanium oxide, zirconium oxide, and antimony trioxide. As the polyolefin resin foam substrate used in the adhesive tape of the present invention, in order to maintain appropriate followability and cushioning properties, it is preferably 0.1% by mass to 10% by mass, more preferably 1% by mass to 7% by mass, relative to the polyolefin resin.

[0066] (Adhesive layer) The adhesive layer of the present embodiment can be formed by using an adhesive composition. Such an adhesive composition constituting the adhesive layer is not particularly limited, and an adhesive composition having good adhesion to the substrate can be used. For example, the adhesive composition of the present embodiment can be an adhesive composition containing one or more adhesives selected from the group consisting of acrylic adhesives, urethane adhesives, rubber adhesives, and silicone adhesives. In addition, in the present embodiment, an adhesive composition containing a water-dispersible emulsion-type adhesive can also be used. As the adhesive composition of the present embodiment, from the aspect of easily obtaining a strong adhesive force, an acrylic adhesive composition is preferred. As this acrylic adhesive composition, a composition obtained by using one or more (meth)acrylic polymers selected from the group consisting of (meth)acrylate homopolymers and copolymers of (meth)acrylates and other monomers as the base polymer (component of the acrylic adhesive) and optionally blending additives such as tackifying resins and crosslinking agents can be preferably used.

[0067] <Acrylic adhesive composition> The adhesive layer of the present embodiment is preferably formed by using an acrylic adhesive composition. The (meth)acrylic polymer as the base polymer (component of the acrylic adhesive) of the acrylic adhesive composition is not particularly limited. For example, it includes at least one polymer containing (meth)acrylic acid alkyl ester monomer as a monomer unit. As the (meth)acrylic acid alkyl ester monomer, for example, it is a (meth)acrylic acid alkyl ester with 2 to 14 carbon atoms in the alkyl group, and there is no particular limitation. For example, methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, sec-butyl (meth)acrylate, tert-butyl (meth)acrylate, isobutyl (meth)acrylate, hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, isooctyl (meth)acrylate, n-nonyl (meth)acrylate, isononyl (meth)acrylate, n-decyl (meth)acrylate, isodecyl (meth)acrylate, n-undecyl (meth)acrylate, n-dodecyl (meth)acrylate, n-tridecyl (meth)acrylate, n-tetradecyl (meth)acrylate and other (meth)acrylic acid alkyl esters can be used. One or more of them can be used. Among them, (meth)acrylic acid alkyl esters with 1 to 8 carbon atoms in the alkyl group are used, especially n-butyl acrylate and 2-ethylhexyl acrylate, which can easily ensure the adhesion to the adherend and have excellent cohesion, so they are preferred. It should be noted that in this specification, "(meth)acrylic acid alkyl ester" means acrylic acid alkyl ester or methacrylic acid alkyl ester.

[0068] Relative to all monomer units constituting the acrylic polymer, the content of the (meth)acrylic acid alkyl ester monomer unit in the (meth)acrylic polymer is preferably 50% by mass to 98.5% by mass, more preferably 80% by mass to 98.5% by mass. As the (meth)acrylic polymer, it is preferable to copolymerize monomers having polar groups such as hydroxyl group, carboxyl group, amide group, etc. in the side chain, such as acrylate monomers and other vinyl-based monomers. Thus, the structural units (= monomer units) from these monomers become crosslinking points in the (meth)acrylic polymer, and the hardness of the adhesive component can be adjusted to exhibit the target adhesive force.

[0069] As the monomer having the hydroxyl group, a vinyl monomer having the hydroxyl group is preferred. For example, hydroxyl group-containing (meth)acrylic acid esters such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, 12-hydroxylauryl (meth)acrylate can be used. Relative to the total amount of the monomer components, the monomer having the hydroxyl group is preferably used in the range of 0.01% by mass to 0.2% by mass, more preferably in the range of more than 0.01% by mass and less than 0.1% by mass, and in terms of setting the tensile strength of the adhesive layer within a specific range and obtaining further excellent adhesive force and holding power, it is more preferably used in the range of 0.02% by mass to 0.08% by mass. As the monomer having the carboxyl group, vinyl monomers having the carboxyl group are preferred, and acrylic acid, methacrylic acid, itaconic acid, maleic acid, (meth)acrylic acid dimer, crotonic acid, etc. can be used. Among them, acrylic acid is preferably used as a copolymerization component. The content of the monomer having the carboxyl group only needs to be an amount such that the acid value of the (meth)acrylic polymer becomes a preferred range, and there is no particular limitation. It is preferably used in the range of 1% by mass to 30% by mass relative to the total amount of the monomer components, more preferably in the range of 1% by mass to 15% by mass, and in terms of obtaining further excellent adhesive force and holding power, it is further preferably used in the range of 1% by mass to 7% by mass. In addition, examples of the monomer having the amide group include N-vinylpyrrolidone, N-vinylcaprolactam, acryloylmorpholine, acrylamide, N,N-dimethylacrylamide, etc. Examples of other highly polar vinyl monomers include vinyl acetate, epoxyethane-modified succinic acid acrylate, sulfonic acid group-containing monomers such as 2-acrylamide-2-methylpropanesulfonic acid, etc.

[0070] It should be noted that when an isocyanate-based crosslinking agent is incorporated into the acrylic adhesive composition, a (meth)acrylic polymer copolymerized from a highly polar vinyl monomer having a functional group reactive with the isocyanate group is preferably used. As the highly polar vinyl monomer having a functional group reactive with the isocyanate group, a vinyl monomer having a hydroxyl group is preferred, and 2-hydroxyethyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate are particularly preferred. The content of the vinyl monomer unit having a hydroxyl group reactive with the isocyanate-based crosslinking agent is preferably 0.01% by mass to 1.0% by mass, and particularly preferably 0.03% by mass to 0.3% by mass, relative to all monomer units constituting the (meth)acrylic polymer.

[0071] The (meth)acrylic polymer of the present embodiment can be obtained by copolymerization using solution polymerization, bulk polymerization, suspension polymerization, emulsion polymerization, ultraviolet irradiation method, or electron beam irradiation method. However, from the viewpoint of the water resistance of the adhesive composition, particularly the base polymer, solution polymerization and bulk polymerization are preferred. The polymerization initiation method can also be arbitrarily selected from the thermal initiation method using a peroxide-based thermal polymerization initiator such as benzoyl peroxide and lauroyl peroxide, an azo-based thermal polymerization initiator such as azobisisobutyronitrile, the ultraviolet irradiation initiation method using a photoinitiator such as acetophenone-based, benzoin ether-based, benzyl ketal-based, acylphosphine oxide-based, benzoin-based, and benzophenone-based, or the method by electron beam irradiation.

[0072] In order to balance coatability and adhesion properties, the weight-average molecular weight of the (meth)acrylic polymer of the present embodiment is preferably 400,000 to 1,600,000, more preferably 600,000 to 1,200,000. The weight-average molecular weight is based on standard polystyrene conversion by gel permeation chromatography (GPC). The measurement conditions for the weight-average molecular weight are as described in the Examples section below. As the adhesive layer formed using the (meth)acrylic adhesive composition, an adhesive layer having a gel fraction of 25% by mass to 70% by mass is preferably used, and an adhesive layer having a gel fraction of 30% by mass to 60% by mass is more preferably used. When the gel fraction is in the above range, both cohesiveness and adhesiveness are good. It should be noted that the calculation method of the above gel fraction is as described in the Examples section below.

[0073] <Rubber-based adhesive composition> The adhesive layer of the present embodiment can be formed by using a rubber-based adhesive composition. As the rubber-based adhesive composition, it contains: natural rubber-based polymers such as natural rubber and its modified products; synthetic rubber-based polymers such as butyl rubber and isoprene rubber; one or more rubber-based adhesives among block copolymer rubber-based polymers such as vinyl aromatic block copolymers and acrylic block copolymers, and additives such as tackifying resins and crosslinking agents can be added as needed. Among them, the rubber-based adhesive composition containing a block copolymer rubber-based polymer has thermoplasticity, so it can be melt-kneaded with the resin constituting the adherend during material recycling, and thus is preferred. Examples of the vinyl aromatic block copolymer include block copolymers containing a polymer block of an aromatic vinyl compound (e.g., styrene, α-methylstyrene) and a polymer block of a conjugated diene compound (e.g., isoprene, butadiene, ethylene butene, ethylene propylene, farnesene). Among them, diblock copolymers such as styrene-isoprene copolymer, styrene-butadiene copolymer, styrene-ethylene butene copolymer, and styrene-ethylene propylene copolymer are preferred; triblock copolymers such as styrene-isoprene-styrene copolymer, styrene-butadiene-styrene copolymer, and styrene-farnesene-styrene copolymer are preferred. Examples of the acrylic block copolymer include block copolymers containing a polymer block of a methacrylate compound (e.g., methyl methacrylate (MMA), ethyl methacrylate (EMA)) and a polymer block of an acrylate compound (e.g., (meth)acrylate alkyl ester having 2 to 14 carbon atoms in the alkyl group, such as n-butyl acrylate (nBA), 2-ethylhexyl acrylate (2EHA)). Among them, triblock copolymers such as MMA-nBA-MMA copolymer, MMA-2EHA-MMA copolymer, and MMA-nBA / 2EHA-MMA copolymer are preferred.

[0074] In addition, as the block copolymer rubber-based polymer, a polymer having a weight average molecular weight of 10,000 to 800,000 measured by gel permeation chromatography (GPC) in terms of standard polystyrene is preferably used, and a polymer having a weight average molecular weight in the range of 30,000 to 500,000 is more preferably used. As the adhesive layer formed using the rubber-based adhesive composition, an adhesive layer having a gel fraction of 0% by mass to 60% by mass is preferably used, and an adhesive layer having a gel fraction of 0% by mass to 40% by mass is more preferably used. Since the rubber-based adhesive composition using the block copolymer rubber-based polymer can design the gel fraction to 0%, it is particularly preferred. It should be noted that the calculation method of the above gel fraction is as described in the Examples section below.

[0075] <Silicone-based adhesive composition> The adhesive layer of the present embodiment can be formed by using a silicone-based adhesive composition. As the silicone-based adhesive composition, as the base polymer (component of the silicone-based adhesive), it usually contains polyorganosiloxanes having different average molecular weights such as a gum component and a resin component, and additives such as a metal catalyst or a crosslinking agent can be added as needed.

[0076] As the adhesive component, a substance mainly serving as an adhesive component can be used. For example, polyorganosilicon or the like can be used. As the polyorganosilicon, peroxide-curable polyorganosilicon and addition-curable polyorganosilicon are known and both can be used. As the addition-curable polyorganosilicon, for example, polyorganosiloxane having a structure in which a polymerizable unsaturated double bond is bonded to a silicon atom can be cited. In addition, as the polyorganosilicon used as the adhesive component, the weight-average molecular weight measured by gel permeation chromatography (GPC) in terms of standard polystyrene is preferably 150,000 or more, more preferably 150,000 to 1,000,000. As the resin component, it can be appropriately selected and used from conventionally known substances. Polyorganosilicon with a lower molecular weight is preferably used, and addition-curable polyorganosilicon is more preferably used. In addition, as the polyorganosilicon used as the resin component, the weight-average molecular weight measured by gel permeation chromatography (GPC) in terms of standard polystyrene is preferably 100 to 10,000, more preferably 300 to 8,000.

[0077] In addition, as the metal catalyst that the organosilicon-based adhesive composition can contain, for example, an organometallic catalyst of Group 10 of the periodic table is preferably used. Specifically, a platinum-based catalyst is more preferably used because of its excellent reaction promotion effect. As the adhesive layer formed using the organosilicon-based adhesive composition, an adhesive layer having a gel fraction of 70% by mass to 99% by mass is preferably used, and an adhesive layer having a gel fraction of 75% by mass to 97% by mass is more preferably used. It should be noted that the calculation method of the above gel fraction is as described in the Examples section below.

[0078] <Crosslinking agent> In order to improve the cohesion of the adhesive layer, the adhesive composition or the adhesive layer of the present embodiment preferably contains a crosslinking agent. Examples of such a crosslinking agent include isocyanate-based crosslinking agents, epoxy-based crosslinking agents, metal chelate-based crosslinking agents, and aziridine-based crosslinking agents. Among them, a crosslinking agent of a type that is preferably added after the polymerization to cause a crosslinking reaction is preferred. Isocyanate-based crosslinking agents and epoxy-based crosslinking agents that have a high reactivity with (meth)acrylic polymers are preferred. In particular, the isocyanate-based crosslinking agent imparts adhesive force, holding power, and the adhesion between the substrate and the adhesive layer. Further, in the material recycling process, the urethane bond formed by the bonding of the isocyanate-based crosslinking agent and the hydroxyl group of the adhesive resin is appropriately cleaved by thermal decomposition, so that it is appropriately compatible with the adherend and the resin of the substrate, and thus is preferred. Examples of the isocyanate-based crosslinking agent include toluene diisocyanate, naphthalene-1,5-diisocyanate, hexamethylene diisocyanate, diphenylmethane diisocyanate, xylylene diisocyanate, trimethylolpropane-modified toluene diisocyanate, etc. A trifunctional polyisocyanate-based compound is particularly preferred. Examples of the trifunctional isocyanate-based compound include toluene diisocyanate and its trimethylolpropane adducts, triphenylmethane isocyanate, etc. In addition, as an index of the crosslinking degree, the value of the gel fraction determined by measuring the insoluble components after immersing the adhesive layer in toluene for 24 hours is used.

[0079] < Tackifying Resin > In order to improve the adhesion of the adhesive layer, the adhesive composition or the adhesive layer of the present embodiment preferably contains a tackifying resin. Examples of the tackifying resin include rosin-based resins, polymerized rosin-based resins, polymerized rosin ester-based resins, abietol-based resins, stabilized rosin ester-based resins, disproportionated rosin ester-based resins, hydrogenated rosin ester-based resins, terpene-based resins, terpene phenol-based resins, petroleum resin-based resins, (meth)acrylate-based resins, etc. In the case of using an emulsion-type adhesive composition, an emulsion-type tackifying resin is preferably used. As preferred tackifying resins, disproportionated rosin ester-based resins, polymerized rosin ester-based resins, abietol-based resins, hydrogenated rosin ester-based resins, and (meth)acrylate-based resins are preferred.

[0080] The softening point of the tackifying resin is not particularly limited, and is 30°C to 180°C, preferably 70°C to 160°C. In addition, one or more kinds of tackifying resins can be used. By blending a tackifying resin with a high softening point, high adhesive performance can be expected. The softening point refers to the value measured by the method (ring and ball method) specified in JIS K6220-1.

[0081] Regarding the mixing ratio when using a (meth)acrylic polymer and a tackifying resin, relative to 100 parts by mass of the acrylic polymer, the content of the tackifying resin is preferably 5 parts by mass to 80 parts by mass, more preferably 7 parts by mass to 70 parts by mass, and further preferably 10 parts by mass to 60 parts by mass. By making the ratio of the two within this range, it is easy to ensure the adhesion to the adherend. In addition, when using a rubber-based adhesive composition as the adhesive, relative to 100 parts by mass of the rubber-based adhesive, it is preferred to add 50 parts by mass to 150 parts by mass of the tackifying resin. It should be noted that generally, when using a silicone-based adhesive as the adhesive, no tackifying resin is added.

[0082] < Other Components > In addition, the adhesive composition or adhesive layer of the present embodiment may contain other well-known and commonly used additives as needed. Specifically, an adhesive composition or adhesive layer that contains the following substances as additives of the adhesive composition as needed within the range that does not impair the properties can be used: other polymer components, ultraviolet absorbers, fillers, polymerization inhibitors, surface modifiers, antistatic agents, defoaming agents, viscosity regulators, light stabilizers, weather stabilizers, heat stabilizers, antioxidants, leveling agents, organic pigments, inorganic pigments, pigment dispersants, plasticizers, softening agents, flame retardants, metal deactivators, resin strengtheners, organic beads and other additives; inorganic fillers such as silica, alumina, titanium oxide, zirconium oxide, antimony pentoxide, etc. Relative to the total amount of the adhesive composition or adhesive layer of the present embodiment, the above additives preferably contain 0% by mass or more and 10% by mass or less, more preferably 0% by mass or more and 5% by mass or less. Among them, the adhesive composition or adhesive layer of the present embodiment preferably contains one or more selected from the group consisting of antioxidants, ultraviolet absorbers, heat stabilizers, and resin strengtheners. Thereby, it has the effect of suppressing the strength deterioration of the resin after melt-kneading, extrusion molding, and recycling in a high-temperature environment.

[0083] Specific examples of the above antioxidants include: 2,6-di-tert-butyl-4-methylphenol, tetra-[methylene-3-(3',5'-di-tert-butyl-4'-hydroxyphenyl)propionate]methane, n-octadecyl 3-(4'-hydroxy-3',5'-di-tert-butylphenyl)propionate, pentaerythritol-tetra[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 3,9-bis[2-{3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propanoyloxy}-1,1-dimethylethyl]-2,4,8,10-tetraoxaspiro[5,5]undecane, etc. Examples of the above ultraviolet absorbers include: benzotriazole-based ultraviolet absorbers, benzophenone-based ultraviolet absorbers, salicylic acid-based ultraviolet absorbers, cyanoacrylate-based ultraviolet absorbers, hindered phenol-based ultraviolet absorbers, and triazine-based ultraviolet absorbers, etc. Examples of the above heat stabilizers include: hindered phenol-based compounds, phosphorus-based compounds, lactone-based compounds, hydroxylamine-based compounds, and sulfur-based compounds. Examples of the above resin strengtheners include well-known materials, preferably fibrous or particulate resin strengtheners, preferably having a size suitable for extrusion molding (100 μm or less).

[0084] <Properties of the Adhesive Layer> The thickness of the adhesive layer is not particularly limited, preferably 5 μm to 100 μm, more preferably 5 μm to 75 μm, and still more preferably 10 μm to 60 μm. By being in this range, it is easy to balance adhesiveness and the thinning of the tape.

[0085] (Method for manufacturing an adhesive tape) The method for manufacturing the adhesive tape of the present embodiment is not particularly limited and can be manufactured by a known method. Specifically, the adhesive tape can be obtained by first manufacturing a laminated film and then cutting the laminated film into a desired shape. As a method for manufacturing the laminated film, for example, it can be manufactured in the following order of (i) to (ii). (i) An adhesive composition is coated on the surface of the release liner and dried, etc., whereby an adhesive layer is formed on one side of the release liner (that is, two release liners formed with an adhesive are produced). At this time, when forming an adhesive layer on the surface of at least one release liner, for example, a part where the adhesive is not coated can be formed on the release liner by a gravure printing method, a die coating method, or a comma coating method, and a non-adhesive part can be formed in the adhesive layer. (ii) Next, the adhesive layer in the state of having the release liner described above is adhered to the surface of the prepared substrate, and pressure is applied as needed, etc.

[0086] In addition, the laminated film or the adhesive tape may be laminated with a release liner for protecting the adhesive layer as needed. As the release liner, there is no particular limitation, and for example, a release liner that has been subjected to a silicone-based treatment, a long-chain alkyl-based treatment, a fluorine-based treatment, etc. for improving the peelability from the adhesive on at least one side or both sides of a substrate such as a synthetic resin film such as polyethylene, polypropylene, or polyester film, paper, non-woven fabric, cloth, foamed sheet, metal foil, and a laminate thereof can be used.

[0087] Another aspect of the present invention is a component containing a thermoplastic resin to which the recyclable adhesive tape of the present embodiment is adhered. As the component, there is no particular limitation, and examples include: electrical and electronic equipment / components, OA equipment / components, information terminal equipment / components, mechanical components, household appliances, mobile body components (aircraft components, railway vehicle components), vehicle components (automobile interior and exterior decorations), building components, various containers, leisure goods / groceries, or lighting equipment. By making the thermoplastic resin contained in the component and the adhesive tape satisfy a specific relational expression (1), the following effects are achieved: it is possible to recycle in a state of being adhered to a component having the thermoplastic resin, and the reduction rate of the tensile strength of the recycled plastic material is small.

[0088] As another aspect of the present invention, the present invention is an electronic device or a mobile body formed using a component containing a thermoplastic resin to which the recyclable adhesive tape of the embodiment is adhered. As the moving body, there is no particular limitation. For example, vehicles, aircraft, ships, bulldozers, forklifts, truck cranes, forklifts, etc. can be cited. Moreover, as the vehicle, the following can be cited: four-wheeled vehicles (sedans, trucks, buses, etc.) fueled by gasoline or bioethanol, electric vehicles using secondary batteries or fuel cells, hybrid vehicles, etc.; two-wheeled motorcycles, bicycles; railway vehicles (trams, hybrid trams, locomotives, bullet trains, linear motor-driven vehicles, etc.). Examples

[0089] Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited by any of the following examples.

[0090] 1. Measurement and evaluation methods The measurement and evaluation of the adhesive tapes obtained in each example and comparative example were carried out based on the following methods.

[0091] (1) Gel fraction (mass%) After laminating the release-treated surface of the release liner on each adhesive layer of the adhesive tape produced in the example, it was cured for 2 days in an environment of 40°C to form an adhesive layer for measuring the gel fraction. The obtained adhesive layer was cut into a square with a length of 50 mm and a width of 40 mm, which was used as a test piece. After measuring the mass (G1) of the above test piece, in an environment of 23°C, the above test piece was immersed in 50 g of toluene for 24 hours, and the mixture of the above test piece and toluene after immersion was filtered using a 300-mesh metal mesh to extract the insoluble components insoluble in toluene, and the mass (G2) of the substance obtained by drying the above insoluble components in an environment of 105°C for 1 hour was measured. The gel fraction was calculated based on the above mass (G1), mass (G2), and the following formula. Gel fraction (mass%) = (G2 / G1) × 100

[0092] (2) The average thickness of the substrate, the average thickness (coating thickness) of the adhesive layer, and the average thickness of the adhesive tape were measured using a dial thickness gauge type G manufactured by Ozaki Manufacturing Co., Ltd. (n number = 3).

[0093] (3) 25% compressive strength (kPa) The 25% compressive strength of the substrate was measured according to JIS K6767. Specifically, the substrate used in each example was cut into a square with a side length of 25 mm and used as a specimen. The specimen was placed on a stainless steel plate larger in area than the specimen, and at 23°C and 50% RH, the specimen was compressed to 25% of the initial thickness at a speed of 0.5 mm / minute using a stainless steel probe with a diameter of 7 mm, and the strength at this time was measured.

[0094] (4) Polyolefin content in the adhesive tape (i.e., content of olefin resin in the adhesive tape) X: Mass of the adhesive layer (g) × Olefin resin content rate of the adhesive layer (mass%) / 100 Y: Mass of the substrate (g) × Olefin resin content rate of the substrate (mass%) / 100 Polyolefin content rate (%) = (X + Y) / Mass of the adhesive tape (g) * 100

[0095] (5) Adhesive tape content rate (mass%) The adhesive tape content (content of the adhesive tape in the whole molded product or the whole recycled plastic material) is calculated from the mixing ratio of the adhesive tape with respect to the whole molded product or the whole recycled plastic material.

[0096] (6) Tensile strength (MPa) and tensile strength strain (%) Using a tensile testing machine (manufactured by Shimadzu Corporation), according to JIS K7161-1, under the measurement conditions of a clamping fixture distance of 115 mm, a gauge length interval of 75 mm, a test speed of 50 mm / minute, and 23°C 50% RH, a tensile test is conducted on the molded products (1) to (4) of the multi-purpose test piece type A1 manufactured later to measure the tensile strength (MPa) and the tensile strength strain (%).

[0097] (7) Flexural strength (MPa) and flexural strength strain (%) Using a tensile testing machine (manufactured by Shimadzu Corporation), according to JIS K7171, under the measurement conditions of a test speed of 2 mm / minute, a lower support point distance of 64 mm, and 23°C 50% RH, a three-point bending test is conducted on the molded products (1) to (4) of the multi-purpose test piece type A1 manufactured later to measure the flexural strength (maximum flexural stress, MPa) and the flexural strength strain (%).

[0098] (8) Confirmation of the dispersion state of the adhesive tape component in the mixture Lay a PET film with a thickness of 100 μm (S-100 of Unitika) over the entire surface of an iron plate of a hot press (TP-750 type manufactured by TESTER SANGYO). Place approximately 2 g of the granules of the recycled plastic materials (1) to (4) obtained below in the central part of the PET film so that the granules do not overlap each other. Then, overlap the same PET film as before on the granules, press at 180°C until the diameter is approximately 14 cm, and form a sheet. Cut the sheet into a 10 cm square, and visually confirm the presence or absence of foreign substances (poor dispersion of the adhesive tape).

[0099] (9) Weight-average molecular weight of the adhesive resin (GPC) The weight-average molecular weight specified in this specification refers to the value calculated by measuring through gel permeation chromatography (GPC method) and performing standard polystyrene conversion. Specifically, the above-mentioned weight-average molecular weight can be measured using a GPC device (HLC-8320GPC) manufactured by Tosoh Corporation under the following conditions. · Sample concentration: 0.5 mass% (tetrahydrofuran solution) · Sample injection volume: 100 μl · Eluent: Tetrahydrofuran · Flow rate: 0.8 ml / minute · Measurement temperature: 40 °C · Column: TSKgel GMHHR-H(20) 2 columns · Guard column: TSKgel HXL-H · Detector: Differential refractometer · Weight-average molecular weight of standard polystyrene: 10,000 - 20,000,000 (manufactured by Tosoh Corporation) The weight-average molecular weight of the binder resin contained in the second coating liquid described later is also the value measured and calculated by the above method.

[0100] 2. Examples (2-1) Preparation of binder composition The binder compositions used in the examples were prepared by the following methods respectively. <Preparation Example 1: Binder composition (P-1)> In a reaction vessel equipped with a stirrer, reflux condenser, nitrogen inlet tube, and thermometer, 79.9 parts by mass of n-butyl acrylate, 6 parts by mass of 2-ethylhexyl acrylate, 10 parts by mass of cyclohexyl acrylate, 4 parts by mass of acrylic acid, 0.1 part by mass of 4-hydroxybutyl acrylate, and 150 parts by mass of ethyl acetate, which are the components of the monomers used, were put in. While blowing nitrogen, the temperature was raised to 72 °C under stirring. Then, 2 parts by mass (solid component 0.1 mass%) of a 2,2'-azobis(2-methylbutyronitrile) solution pre-dissolved in ethyl acetate was added to the above mixture. After maintaining at 72 °C for 4 hours under stirring, it was maintained at 75 °C for 5 hours. The above mixture was diluted with ethyl acetate and filtered through a 200-mesh metal mesh to obtain a solution (solid component concentration 26%) of an acrylic polymer (A-1) with a weight-average molecular weight of 1.06 million.

[0101] To 100 parts by mass of the above acrylic polymer (A-1), 5 parts by mass of a polymerized rosin ester tackifying resin (D-125) (manufactured by Arakawa Chemical Industries, Ltd.) and 15 parts by mass of an aromatic hydrocarbon resin FTR6125 (manufactured by Mitsui Chemicals, Inc.) were mixed and stirred, and then ethyl acetate was added thereto to obtain an adhesive solution having a solid content of 30% by mass. Next, to 100 parts by mass of the above adhesive solution, 1.0 part by mass of BURNOCK D-40A (manufactured by DIC Corporation, an adduct of toluene diisocyanate and trimethylolpropane, nonvolatile content 40% by mass, hereinafter referred to as D-40A) as a crosslinking agent was added and stirred and mixed until homogeneous to obtain an adhesive composition (P-1). The polyolefin resin content of this adhesive composition (P-1) (excluding the solvent) was 0% by mass.

[0102] <Preparation Example 2: Adhesive Composition (P-2)> It was changed to 93.4 parts by mass of n-butyl acrylate, 3.0 parts by mass of vinyl acetate, 3.5 parts by mass of acrylic acid, and 0.1 part by mass of 2-hydroxyethyl acrylate. Except for this, a solution (nonvolatile content 35% by mass) of an acrylic polymer (A-2) having a weight average molecular weight of 1,000,000 was obtained in the same manner as in Preparation Example 1 above.

[0103] To 100 parts by mass of the above acrylic polymer (A-2), 9.3 parts by mass of a polymerized rosin ester tackifying resin (D-125) (manufactured by Arakawa Chemical Industries, Ltd.) and 9.3 parts by mass of a disproportionated rosin ester tackifying resin A-100 (manufactured by Arakawa Chemical Industries, Ltd.) were mixed and stirred, and then ethyl acetate was added thereto to obtain an adhesive solution having a solid content of 38% by mass. Next, to 100 parts by mass of the above adhesive solution, 1.2 parts by mass of BURNOCK D-40A as a crosslinking agent was added and stirred and mixed until homogeneous to obtain an adhesive composition (P-2). The polyolefin resin content of this adhesive composition (P-2) (excluding the solvent) was 0% by mass.

[0104] (2-2) Production of Adhesive Tape (Example 1: Production of Adhesive Tape (1)) On the release-treated surface of the release liner, the adhesive composition (P-1) was coated using a bar coater so that the thickness of the dried adhesive layer was 50 μm, and dried at 80°C for 3 minutes to produce an adhesive layer. Next, the adhesive layer was adhered to a polypropylene-based foamed substrate having a thickness of 300 μm (apparent density 0.2 g / cm 3, on both sides of a substrate (the polyolefin content of the foam substrate is 93.4% by mass, and the wetting index is adjusted to 54 mN / m by corona treating the surface), cure for 48 hours in an environment of 40 °C to produce an adhesive tape (1). The properties of the obtained adhesive tape (1) are shown in Table 1 below.

[0105] (Example 2: Production of adhesive tape (2)) On the surface of a release liner, apply the adhesive composition (P-2) using a rod coater so that the thickness of the dried adhesive layer is 75 μm, and dry at 80 °C for 3 minutes to produce an adhesive layer. Next, paste the adhesive layer on both sides of a polyethylene foam substrate with an average thickness of 200 μm (apparent density 0.2 g / cm 3 , the polyolefin content of the foam substrate is 94.9% by mass, and the wetting index is adjusted to 54 mN / m by corona treating the surface), and cure for 48 hours in an environment of 40 °C to produce an adhesive tape (2). The properties of the obtained adhesive tape (2) are shown in Table 1 below.

[0106] [Table 1]

[0107] 3. Preparation of recycled plastic materials and molded articles (3-1) Preparation of recycled plastic material (1) and molded article (1) using adhesive tape (1) For polypropylene resin (J106G manufactured by Prime Polymer Co., Ltd., melting point 160 °C, granules), mix the above-obtained adhesive tape (1) (release liner peeled off) at a ratio of 1% by mass with respect to the polypropylene resin, and use a twin-screw extruder (KZW25 manufactured by TECHNOVEL Co., Ltd.) heated to 180 °C to carry out melting and kneading at 180 °C, kneading speed 350 rpm, screw speed 300 rpm, and discharge speed 5 kg / h to obtain granules of recycled plastic material (1) containing 1% by mass of adhesive tape (1). Using an injection molding machine (PNX60III manufactured by Nissei Plastic Industrial Co., Ltd., molding machine temperature 180 °C, mold temperature 40 °C), make the granules of the above-obtained recycled plastic material (1) into a molded article (1) of type A1 for general-purpose test pieces of JIS K7139.

[0108] (3-2) Preparation of recycled plastic material (2) and molded article (2) using adhesive tape (1) Mix the obtained adhesive tape (1) (release liner peeled off) in a proportion of 5% by mass relative to the above polypropylene resin. Except for this, through the same operations as those for manufacturing the molded article (1) in the above item (3-1), manufacture pellets of the recycled plastic material (2) and a molded article (2) of multi-purpose test piece type A1 of JIS K 7139.

[0109] (3-3) Preparation of recycled plastic material (3) and molded article (3) using adhesive tape (2) For polyethylene resin (SHC7260 manufactured by Braskem Co., Ltd., softening point 126°C, pellets), mix the obtained adhesive tape (2) (release liner peeled off) in a proportion of 1% by mass relative to the polyethylene resin, and perform melting and kneading using a twin-screw extruder (KZW25 manufactured by TECHNOVEL Co., Ltd.) heated to 146°C under the conditions of 146°C, kneading speed 350 rpm, screw rotation speed 300 rpm, and ejection speed 5 kg / h to obtain pellets of recycled plastic material (3) containing 1% by mass of adhesive tape (2). Using an injection molding machine (PNX60III manufactured by Nissei Plastic Industrial Co., Ltd., molding machine temperature 146°C, mold temperature 40°C), manufacture a molded article (3) of multi-purpose test piece type A1 of JIS K7139 from the pellets of the recycled plastic material (3) obtained above.

[0110] (3-4) Preparation of recycled plastic material (4) and molded article (4) using adhesive tape (2) Mix the above adhesive tape (2) (release liner peeled off) in a proportion of 5% by mass relative to the polyethylene resin. Except for this, through the same operations as those for manufacturing the molded article (3) in the above item (3-3), manufacture a molded article (4) of multi-purpose test piece type A1 of JIS K7139.

[0111] (Reference Example 1: Molded article (C1) of thermoplastic resin (polypropylene resin)) Using an injection molding machine (PNX60III manufactured by Nissei Plastic Industrial Co., Ltd., molding machine temperature 180°C, mold temperature 40°C), manufacture a molded article (C1) of multi-purpose test piece type A1 of JIS K7139 from polypropylene resin (J106G manufactured by Prime Polymer Co., Ltd., melting point 160°C, pellets).

[0112] (Reference Example 2: Molded article (C2) of thermoplastic resin (polyethylene resin)) Using an injection molding machine (PNX60III manufactured by Nissei Plastic Industrial Co., Ltd., molding machine temperature 146°C, mold temperature 40°C), a molded product (C2) of type A1 of the multi-purpose test piece of JIS K7139 was produced from polyethylene resin (SHC7260 manufactured by Braskem Co., Ltd., softening point 126°C, granules).

[0113] 4. Calculation of ratio of tensile strength (σ b / σ a ) and ratio of flexural strength (σ d / σ c ) (4-1) Ratio of tensile strength (σ b / σ a ) and ratio of flexural strength (σ d / σ c ) Using the molded products (1) to (4) of the multi-purpose test piece type A1 obtained above as test pieces, the tensile strength (σ b ) and flexural strength (σ d ) of each test piece were measured under the above conditions. Similarly, using the molded product (C1) and the molded product (C2) as test pieces, the tensile strength (σ a ) and flexural strength (σ c ) of the test pieces of each thermoplastic resin were measured under the above conditions. Next, substituting into the following formulas (1) and (2), the ratio of tensile strength (σ b / σ a ) and the ratio of flexural strength (σ d / σ c ) in the adhesive tapes (1) to (2) of Examples 1 to 2 were calculated respectively. The results are shown in Table 1. Formula (1): Ratio of tensile strength (σ b / σ a ) Formula (2): Ratio of flexural strength (σ d / σ c ) The properties of the recycled plastic materials (1) to (4) and the molded products (1) to (4) using the adhesive tapes (1) to (2) of Examples 1 to 2, the properties of the reference examples (1) and (2), and the ratio of tensile strength (σ b / σ a ) and the ratio of flexural strength (σ d / σ c ) of each adhesive tape are shown in Table 2 below.

[0114] [Table 2]

[0115] From the experimental results of Tables 1 and 2 above, it can be confirmed that the approximation rate "=(the difference in tensile strength and flexural strength before and after recycling / tensile strength and flexural strength after recycling)×100" of the recycled products using the adhesive tapes of Examples 1 and 2 is 92% or more. Therefore, it can be confirmed that the adhesive tape of this example can be recycled in a state of being adhered to an adherend having a plastic resin, and the approximation rate of the tensile strength and flexural strength of the recycled plastic material after recycling this adhesive tape is small. Industrial Applicability

[0116] According to the present invention, it is possible to provide an adhesive tape that can be recycled in a state of being adhered to an adherend having a thermoplastic resin, and the reduction rate of the tensile strength of the recycled plastic material after recycling this adhesive tape is small.

Claims

1. A recyclable adhesive tape, characterized in that: An adhesive tape comprising a substrate and an adhesive layer laminated on at least one surface of the substrate, The pressure-sensitive adhesive tape contains 5% by mass or more and 95% by mass or less of an olefin resin having an olefin monomer unit relative to 100% by mass of the total amount of the pressure-sensitive adhesive tape, The adherend having a thermoplastic resin to which the adhesive tape is attached and the adhesive tape satisfy the following relational expression (1): 0.8≤σ b / s a ≤1.2 (1) In the above relationship (1), σ a is the tensile strength of the thermoplastic resin, σ b The tensile strength of a test piece prepared by mixing an adhesive tape and the thermoplastic resin under the following conditions is: The production conditions of the test piece are: After heating the mixture of the adhesive tape and the thermoplastic resin at the melting point of the thermoplastic resin + 20°C, resin pellets were prepared using a twin-screw extruder under the conditions of a kneading speed of 350 rpm, a screw speed of 300 rpm and a discharge speed of 5 kg / h, and then a multi-purpose test piece type A according to JIS K 7139 was prepared using an injection molding machine and used as the test piece.

2. The recyclable adhesive tape according to claim 1, wherein The adherend having a thermoplastic resin to which the adhesive tape is attached and the adhesive tape also satisfy the following relational expression (2): 0.8≤σ d / s c ≤1.2 (2) In the above relationship (2), σ c is the flexural strength of the thermoplastic resin, σ d is the bending strength of the test piece.

3. The recyclable adhesive tape according to claim 1, wherein: The base material has the same chemical structure as the thermoplastic resin or the same chemical structure as the main chain of the thermoplastic resin.

4. The recyclable adhesive tape according to claim 1, wherein: The substrate contains the olefin-based resin.

5. The recyclable adhesive tape according to claim 4, wherein: The olefin-based resin includes a polyethylene resin or a polypropylene resin.

6. The recyclable adhesive tape according to claim 1, wherein: The substrate is a foam substrate.

7. The recyclable adhesive tape according to claim 1, wherein: The adhesive layer contains an acrylic adhesive.

8. The recyclable adhesive tape according to claim 1, wherein: The thermoplastic resin contains an olefin-based resin.

9. The recyclable adhesive tape according to claim 8, wherein: The olefin-based resin includes a polyethylene resin or a polypropylene resin.

10. The recyclable adhesive tape according to claim 1, wherein: The content of the adhesive tape contained in the mixture is 10% by mass or less relative to the total amount of the mixture.

11. The recyclable adhesive tape according to claim 1, wherein: The adhesive tape contains one or more selected from an antioxidant, an ultraviolet absorber, a heat stabilizer, and a resin reinforcing agent. 12 . A member comprising a thermoplastic resin to which the recyclable adhesive tape according to claim 1 is adhered.

13. An electronic device formed using the component of claim 12.

14. A vehicle formed using the component of claim 12.

Images