Adhesive tape, component, electronic device and vehicle

Abstract

To provide an adhesive tape that is recyclable in a state of being stuck to an adherend having a thermoplastic resin, which has a small reduction rate of tensile strength in a recycled plastic material after the adhesive tape is recycled.SOLUTION: An adhesive tape has a base material, and an adhesive layer stacked on at least one surface of the base material, wherein the adhesive tape contains 5 mass% or more and 95 mass% or less of an olefinic resin having an olefinic 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 stuck, and the adhesive tape satisfy a relation expression (1), and the adhesive tape is recyclable.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to adhesive tapes, components, electronic devices, and vehicles.

Background Art

[0002] Adhesive tapes are excellent in workability and have high adhesion reliability. Therefore, as a joining means, they are widely used in various industrial fields such as OA equipment, IT and home appliances, and automobiles for component fixing purposes, temporary fixing purposes of components, label purposes for displaying product information, etc. Generally, adhesive tapes have adhesive strength (peel strength) or tack (adhesiveness) as basic characteristics, but depending on the use of the adhesive tape, various other characteristics may be required.

[0003] In recent years, along with the improvement of awareness regarding environmental load reduction such as reducing the adverse effects on the marine environment or ecosystem caused by inappropriate disposal of used plastic products, containers, etc., the concept of "sustainable development" has begun to be advocated. Therefore, not only in various industrial fields such as home appliances and automobiles that use adhesive tapes, but also in the chemical industrial field that manufactures the adhesive tapes, the awareness of recycling used products is increasing. For the purpose of such environmental load reduction, when recycling various products such as home appliances or automobiles, the used products are disassembled and each component in the product is removed. When removing each component, it is necessary to perform the operation of peeling off the adhesive tape used for fixing the component or the label. However, the adhesive tape is provided at various places in the product, and there is a demand for it to be more easily recyclable. For example, as a technique of an adhesive tape for the purpose of recycling, Patent Document 1 can be cited. Patent Document 1 discloses a technique of an adhesive tape capable of recycling a polyethylene tube with the adhesive tape attached as it is into a high-quality polyethylene polymer.

Prior Art Documents

Patent Documents

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

[0005] However, in Patent Document 1, although the tensile strength is examined as a characteristic of the recycled plastic material after recycling a polyethylene tube with an adhesive tape attached, specifically, it is not disclosed how much tensile strength the recycled plastic material exhibits as compared with the polyethylene tube (polyethylene before recycling), and there remains a doubt as to whether the recycled plastic material can exhibit desired characteristics. Therefore, an object of the present disclosure is to provide an adhesive tape that can be recycled while being attached to an adherend having a thermoplastic resin, and in which the rate of decrease in tensile strength of the recycled plastic material after recycling the adhesive tape while it is attached is small. Means for Solving the Problems

[0006] As a result of intensive studies to solve the problems of the above prior art, the present inventors have found that by satisfying a specific relational expression between the thermoplastic resin contained in the adherend and an adhesive tape having a base material and an adhesive layer laminated on at least one surface of the base material, it becomes possible to recycle while being attached to the adherend having the thermoplastic resin, and to provide an adhesive tape in which the rate of decrease in tensile strength of the recycled plastic material after recycling is small, and thus the present invention has been achieved. That is, the present disclosure is as follows.

[0007] [1] 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 an olefin-based resin having an olefin-based monomer unit in an amount of 5% by mass or more and 95% by mass or less based on the total amount (100% by mass) of the adhesive tape, A recyclable pressure-sensitive adhesive tape, wherein the adherend having a thermoplastic resin to which the pressure-sensitive adhesive tape is adhered and the pressure-sensitive 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 prepared by the following conditions for the pressure-sensitive adhesive tape and the thermoplastic resin in the adherend.) <Preparation conditions of the test piece> After heating a mixture of the pressure-sensitive adhesive tape and the thermoplastic resin at the melting point of the thermoplastic resin + 20°C, resin pellets were produced by a twin-screw extruder under the conditions of a kneading speed of 350 rpm, a screw rotation speed of 300 rpm, and a discharge speed of 5 kg / h. Then, using an injection molding machine, a multi-purpose test piece type A conforming to JIS K 7139 was used as the test piece.)

[0008] [2] The recyclable pressure-sensitive adhesive tape according to [1], wherein the adherend having a thermoplastic resin to which the pressure-sensitive adhesive tape is adhered and the pressure-sensitive 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, and σ d is the flexural stress of the test piece.)

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

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

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

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

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

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

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

[0016]

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

[0017]

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

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

[0018]

[12] A part made of a thermoplastic resin to which the recyclable pressure-sensitive adhesive tape according to any one of [1] to

[11] is attached.

[0019]

[13] An electronic device or a vehicle formed using the part according to

[12] .

Advantages of the Invention

[0020] According to the present disclosure, there is provided an adhesive tape that can be recycled while being attached to an adherend having a thermoplastic resin, and the adhesive tape has a low rate of decrease in tensile strength in the recycled plastic material after recycling while the adhesive tape remains attached.

Mode for Carrying Out the Invention

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

[0022] [Adhesive Tape] The present disclosure 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 an olefin resin having an olefin monomer unit in an amount of 5% by mass or more and 95% by mass or less based on the total amount (100% by mass) of the adhesive tape, the adhesive tape and an adherend having a thermoplastic resin to which the adhesive tape is attached satisfy the following relational expression (1), and it is a recyclable adhesive tape. [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 prepared by the following conditions for the adhesive tape and the thermoplastic resin in the adherend. <Preparation Conditions of the Test Piece> After heating a mixture of the adhesive tape and the thermoplastic resin at the melting point of the thermoplastic resin + 20°C, resin pellets were produced by a twin-screw extruder under the conditions of a kneading speed of 350 rpm, a screw rotation speed of 300 rpm, and a discharge speed of 5 kg / h. Then, using an injection molding machine, a multi-purpose test piece type A conforming to JIS K 7139 was used as the test piece.) This is an adhesive tape that can be recycled while being attached to an adherend having a thermoplastic resin, and can exhibit an effect of having a low rate of decrease in tensile strength in the recycled plastic material after material recycling of the adhesive tape. In addition, "recycling" as used in this specification means (i) a method of collecting used products or products scheduled to be discarded (e.g., pre-consumers) or discarded products and using them as raw materials (materials) (material recycling), (ii) a method of incinerating waste on the premise of final disposal and using the combustion heat as energy (thermal recycling), and (iii) a method of recycling by performing pyrolysis or the like on waste plastics to convert them into oil, gasify them, or reduce them in a blast furnace (chemical recycling). Among these three modes, it means material recycling. Moreover, although a known extrusion molding machine can be used to produce resin pellets, a twin-screw extruder is preferred. Hereinafter, after explaining the main configuration and components of the adhesive tape of the present embodiment, 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 the present embodiment includes a base material and an adhesive layer on at least one surface of the base material. The adhesive layer may be present so as to directly contact the base material, or the adhesive layer may be laminated on one surface of the base material via a known easy-adhesion treatment layer between the base material and the adhesive layer. Further, since the adhesive layer only needs to be laminated on at least one surface of the base material, the adhesive layer may be laminated only on one side of the base material, or the adhesive layer may be laminated on both sides of the base material. In the case of a double-sided adhesive specification, the adhesive layers provided on each surface of the base material layer may be the same or different from each other. Furthermore, it may be present so as to directly contact the base material on a part of at least one surface of the base material, or the adhesive layer may be present so as to directly contact the base material on at least one entire surface of the base material. As a preferred embodiment of the adhesive tape of the present embodiment, a double-sided adhesive specification is a preferred structure.

[0024] (Main material of the adhesive tape) The adhesive tape of the present embodiment contains an olefin resin having an olefin monomer unit in an amount of 5% by mass or more and 95% by mass or less based on the total amount (100% by mass) of the adhesive tape. Thereby, since compatibility with an olefin resin material generally widely used as a material of an adherend of the adhesive tape can be ensured, it can be recycled in a state of being attached to the adherend. From the viewpoints of dimensional stability, mechanical strength of the base material layer of the adhesive tape, and manifestation of adhesive physical properties of the adhesive layer, the olefin resin is preferably contained in the material of the base material. The upper limit of the content of the olefin resin with respect 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. The preferable range of the content of the olefin resin can be appropriately combined with the above upper and lower limit values. 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 olefin resin can be arbitrarily reorganized. Note that the calculation method of the content of the olefin resin with respect 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 base material, particularly a foam base material, excellent in flexibility, followability, and mechanical strength, it is preferable to contain a polyethylene resin and / or a polypropylene resin, and an ethylene-propylene copolymer resin. Note that, as described later, in the adhesive tape of the present embodiment, it is preferable that an olefin resin is used as the material of the base material.

[0025] (Thermoplastic resin) The pressure-sensitive adhesive tape of this embodiment can be attached to an adherend having a thermoplastic resin. When an adherend containing a thermoplastic resin is the object to which the pressure-sensitive adhesive tape of this embodiment is to be attached, since the adherend containing the thermoplastic resin is easily melted by heat and can be easily remolded into a desired shape, it is preferable from the viewpoint of material recycling. Examples of the thermoplastic resin include thermoplastic polyurethane (TPU); polycarbonate (PC) resin; polyvinyl chloride (PVC), vinyl chloride resins such as vinyl chloride-vinyl acetate copolymer resin; acrylic resins such as polyacrylic acid, polymethacrylic acid, methyl polyacrylate, polymethyl methacrylate (PMMA), ethyl polymethacrylate; polyester resins such as polyethylene terephthalate (PET), polybutylene terephthalate, polytrimethylene terephthalate, polyethylene naphthalate, polybutylene naphthalate; 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 and other polystyrene resins, polyethylene (PE) resin, polypropylene (PP) resin, olefin resins such as cycloolefin resin; polyacetal (POM) resin; cellulose resins such as nitrocellulose, cellulose acetate; silicone resin; fluororesin and the like. It is preferable that the thermoplastic resin, which is the material of the adherend to which the pressure-sensitive adhesive tape of this embodiment is attached, and the material constituting the pressure-sensitive adhesive tape have a common chemical structure or have the same chemical structure as the main chain of the thermoplastic resin. Thereby, since the two are compatible, the reduction rate of the tensile strength in the recycled plastic material after material recycling is further reduced. As the thermoplastic resin of the present embodiment, olefin resins such as polyethylene (PE) resin, polypropylene (PP) resin, and cycloolefin resin are preferably used, and polyethylene (PE) resin and polypropylene (PP) resin are more preferred. Thereby, since the material constituting the adhesive tape, particularly the material of the base material, can be selected as an olefin resin with excellent mechanical properties, the rate of decrease in tensile strength in the recycled plastic material after material recycling is less, and it is preferable from the viewpoint of facilitating the use of the recycled plastic material for the same applications as before recycling.

[0026] (Adherend) The adherend of the present embodiment is not particularly limited as long as it contains a thermoplastic resin. For example, it is used in various industrial fields such as OA equipment, IT / home appliances, and automobiles. The adherend may be components such as the housings of those products, the batteries, electronic components, and structural components incorporated in those products. Specifically, it may be electric and electronic equipment and its components, OA equipment and its components, information terminal equipment and its components, mechanical components, home appliances and its components, moving bodies (aircraft, railway vehicles) and its components, vehicle components (automobile interior and exterior), building members, various containers and its components, leisure goods / groceries and its components, or lighting equipment / components. In addition, the adherend can be fixed or temporarily fixed by the adhesive tape of the present embodiment. Furthermore, for example, the adhesive tape of the present embodiment itself may be a label that displays product information and the like. The content of the thermoplastic resin in the adherend of the present embodiment is not particularly limited as long as it satisfies the required performance of the adherend. However, from the viewpoint of recycling, it is preferable to contain more thermoplastic resin. Therefore, for example, it is preferably contained in an amount of 50% by mass or more, and more preferably 60% by mass or more. Note that the adherend of the present embodiment may be formed only from a thermoplastic resin.

[0027] (Relational Expression (1)) The adhesive tape of the present embodiment satisfies the following relational expression (1) with the adherend having a thermoplastic resin to which the adhesive tape is attached and the adhesive tape. [Number 1] 0.8 ≤ σ b / σ a ≤ 1.2 (1) (In the above relational expression (1), σ a is the tensile strength (MPa) of the thermoplastic resin, and σ b is the tensile strength (MPa) of a test piece prepared under the following conditions using the adhesive tape and the thermoplastic resin in the adherend.) <Manufacturing conditions of the test piece> After heating a mixture of the adhesive tape and the thermoplastic resin at the melting point of the thermoplastic resin + 20°C, resin pellets were produced using a twin-screw extruder under the conditions of a kneading speed of 350 rpm, a screw rotation speed of 300 rpm, and a discharge speed of 5 kg / h. Then, using an injection molding machine, a multi-purpose test piece type A conforming to JIS K 7139 was used as the test piece.) Accordingly, it is possible to provide an adhesive tape excellent in material recyclability with a small reduction rate of the tensile strength in the recycled plastic material after recycling.) The ratio of the tensile strength (σ a ) of the thermoplastic resin, which is the material of the adherend of the adhesive tape, to the tensile strength (σ b ) of the resin material regenerated from the mixture of the adhesive tape and the thermoplastic resin, represented by σ b / σ a being in the range of 0.8 to 1.2 means that the mechanical properties of the thermoplastic resin, which is the material before kneading and melting (= before recycling), and the alloy resin of the adhesive tape and the thermoplastic resin, which is the material after kneading and melting (= after recycling), are approximated (within ±20%). More specifically, considering that the tensile strength means the maximum stress that the material can withstand in a series of processes of elastic deformation - plastic deformation - fracture - breakage, the state where the tensile strengths of both resins are approximated means that the adhesive tape and the thermoplastic resin are mutually compatible in the alloy resin after recycling.) Therefore, in terms of morphology, for the adhesive tape and the alloy resin of the thermoplastic resin, which are the materials after recycling, in the alloy resin, since the so-called component derived from the adhesive tape and the so-called component derived from the thermoplastic resin are compatible, it is considered that the alloy resin exhibits the same tensile strength as the thermoplastic resin before kneading and melting (= before recycling). As a result, it is considered that the recycled plastic material after recycling has the effect of a low reduction rate of tensile strength. The tensile strength (σ a ) of the thermoplastic resin, which is the material of the adherend of the adhesive tape, with respect to the tensile strength (σ b ) of the resin material regenerated from the mixture of the adhesive tape and the thermoplastic resin, and the ratio represented by σ b / σ a is preferably in the range of 0.88 to 1.16, and more preferably in the range of 0.92 to 1.1.

[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 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 based on 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 monomaterial. Further, 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 more 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 tensile strength (σ a ) of the thermoplastic resin, which is the material of the adherend of the adhesive tape, with respect to the tensile strength (σ b ) of the resin material regenerated from the mixture of the adhesive tape and the thermoplastic resin, and the ratio represented by σb / σ a falls within the preferred range of the present invention and is preferred in that the deterioration of physical properties after recycling is suppressed.

[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. In accordance with JIS K7161-1, using a tensile testing machine (manufactured by Shimadzu Corporation), the measurement is carried out under the measurement conditions of a grip distance of 115 mm, a gauge length of 75 mm, a test speed of 50 mm / min, and 23°C and 50% RH.

[0030] (Relational expression (2)) The adhesive tape of the present embodiment preferably further satisfies the following relational expression (2) with the adherend having the thermoplastic resin to which the adhesive tape is adhered and the adhesive tape. [Equation 2] 0.8 ≦ σ d / σ c ≦ 1.2 (2) (In the above relational expression (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 excellent in material recyclability with a smaller reduction rate of the tensile strength in the recycled plastic material after recycling. The ratio of the flexural strength (σ c ) of the thermoplastic resin, which is the material of the adherend of the adhesive tape, to the flexural strength (σ d ) of the resin material regenerated from the mixture of the adhesive tape and the thermoplastic resin is represented by σ d / σ cWhen it is within the range of 0.8 to 1.2, similar to the above tensile strength, it means that the mechanical properties of the thermoplastic resin, which is the material before kneading and melting (= before recycling), and the adhesive tape and the alloy resin of the thermoplastic resin, which are the materials after kneading and melting (= after recycling), are approximated (within ±20%). Therefore, it indicates that the adhesive tape and the thermoplastic resin are mutually compatible in the alloy resin after recycling. Therefore, morphologically explaining the adhesive tape and the alloy resin of the thermoplastic resin, which are the materials after recycling, in the alloy resin, since the so-called components derived from the adhesive tape and the so-called components derived from the thermoplastic resin are compatible, it is considered to exhibit a flexural strength equivalent to that of the thermoplastic resin, which is the material before kneading and melting (= before recycling). Thereby, it is considered that the effect of a small reduction rate of the tensile strength in the recycled plastic material after recycling is achieved. The flexural strength (σ c ) of the thermoplastic resin, which is the material of the adherend of the adhesive tape, with respect to the flexural strength (σ d ) of the resin material regenerated from the mixture of the adhesive tape and the thermoplastic resin, the ratio represented by σ d / σ c is preferably in the range of 0.88 to 1.16, and more preferably in the range of 0.92 to 1.1. When calculating the above relational expression (2), the content of the pressure-sensitive adhesive tape contained in the mixture of the pressure-sensitive adhesive tape and the thermoplastic resin can be arbitrarily set according to the usage mode. For example, the content of the pressure-sensitive adhesive tape contained in the mixture of the pressure-sensitive adhesive tape and the thermoplastic resin is preferably 10% by mass or less based on 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 that the recycled resin is easily used as a monomaterial. Further, the upper limit of the content of the pressure-sensitive 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 pressure-sensitive adhesive tape contained in the mixture is preferably more 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 pressure-sensitive adhesive tape contained in the mixture of the pressure-sensitive adhesive tape and the thermoplastic resin is within the above range, the bending strength (σ c ) of the resin material regenerated from the mixture of the pressure-sensitive adhesive tape and the thermoplastic resin with respect to the bending strength of the thermoplastic resin which is the material of the adherend of the pressure-sensitive adhesive tape (σ d ) The ratio represented by σ d / σ c falls within the preferred range of the present invention, and it is preferable in that the deterioration of physical properties after recycling is suppressed.

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

[0032] In the present embodiment, the requirements showing a tendency to easily satisfy the above relational expression (1) include the following (I-1) to (IX-1). (I-1) It is preferable that the base material or the adhesive layer of the adhesive tape has the same resin as the thermoplastic resin or a resin containing a partial chemical structure contained in the thermoplastic resin. Among these, it is more preferable that the base material has the same resin as the thermoplastic resin or a resin containing a partial chemical structure contained in the thermoplastic resin. (II-1) It is preferable that 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 these, polyethylene (PE) resin and polypropylene (PP) resin are more preferable. (III-1) It is preferable that 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 these, polyethylene (PE) resin, polypropylene (PP) resin, and ethylene-propylene copolymer resin are more preferable. (IV-1) It is preferable that the thermoplastic resin is an olefin resin such as polyethylene (PE) resin, polypropylene (PP) resin, cycloolefin resin. Among these, polyethylene (PE) resin and polypropylene (PP) resin are more preferable. (V-1) It is preferable that the weight average molecular weight of the adhesive composition constituting the adhesive layer of the adhesive tape is from 400,000 to 1,600,000. (VI-1) It is preferable that 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-based resin, and a (meth)acrylate-based resin. (VII-1) It is preferable that the adhesive layer of the adhesive tape is formed by using an acrylic adhesive composition or a rubber-based adhesive composition. (VIII-1) It is preferable that the content of the olefin resin with respect to the total amount (100% by mass) of the adhesive tape is 5% by mass or more and 90% by mass or less. Preferably, the ratio of the pressure-sensitive adhesive tape to the total mass of the mixture of the pressure-sensitive adhesive tape and the thermoplastic resin is 10% by mass or less. By satisfying the above conditions (I-1) to (IX-1), the compatibility between the thermoplastic resin and the pressure-sensitive adhesive tape is improved. Further, since the mixture of the pressure-sensitive adhesive tape and the thermoplastic resin and the thermoplastic resin have similar crystallinity (molecular orientation) and intermolecular interaction, the tensile strength (σ a ) of the resin material regenerated from the mixture of the pressure-sensitive adhesive tape and the thermoplastic resin with respect to the tensile strength (σ b ) of the resin material of the thermoplastic resin which is the adherend of the pressure-sensitive adhesive tape is represented by σ b / σ a falls within the preferred range of the present invention, which is preferable in that the deterioration of physical properties after recycling is suppressed.

[0033] Similarly, in the present embodiment, the requirements that tend to easily satisfy the above relational expression (2) include the following (I-2) to (IX-2). (I-2) It is preferable that the base material or the adhesive layer of the pressure-sensitive adhesive tape has the same resin as the thermoplastic resin or a resin containing a partial chemical structure contained in the thermoplastic resin. Among them, it is more preferable that the base material has the same resin as the thermoplastic resin or a resin containing a partial chemical structure contained in the thermoplastic resin. (II-2) It is preferable that the base material or the adhesive layer of the pressure-sensitive adhesive tape is an olefin resin such as polyethylene (PE) resin, polypropylene (PP) resin, cycloolefin resin, or has these resins. Among these, polyethylene (PE) resin, polypropylene (PP) resin, and ethylene-propylene copolymer resin are more preferable. (III-2) It is preferable that the base material constituting the pressure-sensitive adhesive tape is an olefin resin such as polyethylene (PE) resin, polypropylene (PP) resin, cycloolefin resin, or has these resins. Among these, polyethylene (PE) resin, polypropylene (PP) resin, and ethylene-propylene copolymer resin are more preferable. (IV-2) It is preferable that the thermoplastic resin is an olefin resin such as polyethylene (PE) resin, polypropylene (PP) resin, cycloolefin resin, etc., and among them, polyethylene (PE) resin and polypropylene (PP) resin are more preferable. (V-2) It is preferable that the weight average molecular weight of the pressure-sensitive adhesive composition constituting the pressure-sensitive adhesive layer of the pressure-sensitive adhesive tape is from 400,000 to 1,600,000. (VI-2) It is preferable that the pressure-sensitive adhesive layer of the pressure-sensitive 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-based resin, a (meth)acrylate-based resin. (VII-2) It is preferable that the pressure-sensitive adhesive layer of the pressure-sensitive adhesive tape is formed by using an acrylic pressure-sensitive adhesive composition or a rubber-based pressure-sensitive adhesive composition. (VIII-2) It is preferable that the content of the olefin resin with respect to the total amount (100% by mass) of the pressure-sensitive adhesive tape is 5% by mass or more and 90% by mass or less. (IX-2) It is preferable that the ratio of the pressure-sensitive adhesive tape to the total mass of the mixture of the pressure-sensitive adhesive tape and the thermoplastic resin is 10% by mass or less. By satisfying the above conditions (I-2) to (IX-2), the compatibility between the thermoplastic resin and the pressure-sensitive adhesive tape is improved. Furthermore, since the mixture of the pressure-sensitive adhesive tape and the thermoplastic resin and the thermoplastic resin have similar crystallinity (molecular orientation) and intermolecular interaction, the bending strength (σ c ) of the thermoplastic resin, which is the material of the adherend of the pressure-sensitive adhesive tape, with respect to the bending strength (σ d ) of the resin material regenerated from the mixture of the pressure-sensitive adhesive tape and the thermoplastic resin. The ratio represented by σ d / σ c falls within the preferable range of the present invention, and it is preferable in that the deterioration of physical properties after recycling is suppressed.

[0034] The pressure-sensitive adhesive tape of the present embodiment is preferably manufactured from biomass raw materials. Specifically, the lower limit of the biomass carbon content rate (%) of the pressure-sensitive adhesive tape of the present embodiment is preferably 10% or more, 13% or more, 15% or more, 17% or more, 20% or more, 25% or more, and 35% or more in this order with respect to all carbon atoms in the pressure-sensitive 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, and 68% or less in this order. The upper limit and the lower limit can be arbitrarily combined. For example, the range of the biomass carbon content rate (%) of the pressure-sensitive adhesive tape is preferably 10% or more, more preferably 10% or more and 90% or less, still more preferably 20% or more and 80% or less, and even more preferably 22% or more and 73% or less. When the biomass carbon content rate (%) of the pressure-sensitive 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 a correction ratio of 0.93, 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 manufactured from biomass raw materials. Specifically, the lower limit of the biomass carbon content rate (%) of the thermoplastic resin of the present embodiment is preferably 10% or more, 13% or more, 15% or more, 17% or more, 20% or more, 25% or more, and 35% or more in this order with respect to all carbon atoms in the pressure-sensitive 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, and 68% or less in this order.

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

[0037] The content ratio (pMC%) of radiocarbon ( 14 C) in this specification indicates the carbon concentration (mass ratio) of biomass-derived components 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 a radiocarbon ( 14 C) measurement method in accordance with ASTM-D6866 (especially ASTM D6866 Method B). Radiocarbon ( 14 C) is known to have the property of radioactive decay into nitrogen ( 14 N) with a half-life of 5730 years. And the radiocarbon ( 14 C) that is constantly generated in trace amounts on the earth due to the action of cosmic rays pouring down from the universe is carbon dioxide 14After being oxidized to CO2 and diffused into the atmosphere, it is taken into animals and plants during the process of the food chain, circulates in the environment through the food chain, and disappears according to the half-life. Therefore, the radiocarbon ( 14 C) measurement method utilizes the fact that fossil fuels do not substantially contain radiocarbon ( 14 C), and carbon derived from biomass (or organisms) absorbs the radiocarbon ( 14 C) in the atmosphere at the time of growth. It is a method of estimating the content ratio (pMC%) of radiocarbon ( 14 C) from the ratio of radiocarbon ( 14 C) in the carbon contained in the biomass material (or organism). Therefore, the larger the value of the content ratio (pMC%) of radiocarbon ( 14 C), the less the amount of fossil fuel used, and the effect of reducing the environmental load can be exerted. Therefore, the value of the content ratio (pMC%) of radiocarbon ( 14 C) is related to the blending ratio of biomass, which is a renewable, organism-derived organic resource (= biomass carbon content rate (%)).

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

[0039] Note that due to the influence of atmospheric nuclear tests after 1950, radioactive carbon ( 14 C) artificially injected into the atmosphere has caused about 1.5 times the normal amount of radioactive carbon ( 14 C) to be observed. However, it has been gradually decreasing over time, and the current value is around 107.5 (pMC%). Therefore, also in the present disclosure, similar to the standard of ASTM D6866, the value obtained by multiplying the content ratio (pMC%) of radioactive carbon ( 14 C) by 0.93 (= 100 / 107.5) is defined as the biomass carbon content rate (%). However, when a value of 100% or more is calculated even when the method using the above formula (Y) is adopted. Therefore, in the present disclosure, 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, the concentration measurement of radioactive carbon ( 14 C) is performed by accelerator mass spectrometry (AMS: Accelerator Mass Spectrometry) combining a tandem accelerator and a mass spectrometer, and the isotopes of carbon atoms contained in the sample to be analyzed (specifically 12 C, 13 C, 14 C, etc.) are physically separated by an accelerator using the atomic weight difference, and the abundance of each isotope atom is measured using a method of measuring.) In addition, for the sample to be analyzed, which is a thermoplastic resin in the adhesive tape or adherend, pretreatment is required. Specifically, the carbon contained in the sample is oxidized and all converted into carbon dioxide. Further, the obtained carbon dioxide is separated from water and nitrogen, and the carbon dioxide is reduced and converted into graphite, which is solid carbon. This obtained graphite is used as a measurement sample, and cations such as Cs + are irradiated onto the sample to generate negative carbon ions. The carbon ions are accelerated using a 3MV tandem accelerator, charge-converted from negative ions to positive ions, and 12 C 3+ , 13 C 3+ , 14 C 3+ The orbits of are separated, and 14 C 3+ is measured by an electrostatic analyzer. The accelerator mass spectrometry of this embodiment adopts this method. In addition, the carbon isotopes contained in the graphite obtained from the pretreated sample 12 C, 13 C and 14 C are accelerated at the same speed and the flight lines are bent by the magnetic field of the mass spectrometry electromagnet. At that time, 12 C, 13 C are on the inner side, and the heaviest 14 C flies on the outermost side of the bending part. Also, 12 C, 13 Since the amount of C is large in number, it is detected by a Faraday cup detector as a current, and 14 C is counted one by one by an ionization box-type ion detector.

[0041] Hereinafter, the base material and the adhesive layer constituting the adhesive tape will be described. (Base material) The adhesive tape of this embodiment has a base material as a carrier of the adhesive layer. Also, when the adhesive tape of this embodiment is 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 this embodiment is not particularly limited, and examples thereof include resin base materials, foam base materials, non-woven fabrics, rubber sheets, woven fabrics, paper, glass, metal foils, composites thereof, and the like. The resin base material is a non-foamed or non-porous resin film or sheet, which is distinguished from non-woven fabrics or foam base materials. Among them, when emphasizing the viewpoint that high adhesiveness can be exhibited between the adhesive layer and the base material, and that it can be easily colored and is likely to exhibit shielding properties and design properties due to the color of the base material, the resin base material is preferred as the base material. On the other hand, when emphasizing the point that it has excellent adhesion to the adherend and can preferably follow even an adherend having an uneven shape or a rough surface and has excellent adhesion, the foam base material is preferred as the base material. It is preferable that the base material of this embodiment 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. Thus, it is possible to provide an adhesive tape that can be recycled in a state of being attached to an adherend having a thermoplastic resin, and in which the rate of decrease in tensile strength in the recycled plastic material after recycling the adhesive tape is less.

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

[0044] For the purpose of improving the adhesion to the adhesive layer, the base material may have a primer layer on its surface or may be surface-treated. Examples of the surface treatment include roughening treatment such as sandblasting method and solvent treatment method, corona discharge treatment, atmospheric pressure plasma treatment, chromic acid treatment, flame treatment, hot air treatment, ozone-ultraviolet irradiation treatment, oxidation treatment, anchor coat treatment, and the like. Also, the surface of the base material may be subjected to antistatic treatment.

[0045] <Resin base material> As the resin base material of the present embodiment, for example, sheets or films obtained using polyester resins such as polyester, polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, olefin resins (polyethylene resin, polypropylene resin), polyacrylate, polyvinyl chloride, polypropylene ethylene vinyl alcohol, polyurethane resin, polyamide resin, polyimide resin, etc. can be used. As the resin base material, those subjected to corona treatment, anchor coat treatment, etc. can be used in order to improve the anchoring property of the adhesive layer. When the base material of the present embodiment is a resin base material, olefin resins (polyethylene resin, polypropylene resin, ethylene-propylene copolymer resin) are preferred.

[0046] The average thickness of the resin base material of the present embodiment can be appropriately set according to the use of the adhesive tape. It is preferably 1 to 150 μm, more preferably 2 to 120 μm, and even more preferably 3 to 100 μm. When the thickness of the base material is within the above range, the adhesive tape can easily follow the distortion of the adherend and it is preferable because it is easy to obtain high adhesive strength. As the resin base material, for the purpose of further improving the adhesion with the adhesive layer, those provided with a primer layer, those subjected to surface roughening treatment such as sandblasting method or solvent treatment method, corona discharge treatment, chromic acid treatment, flame treatment, hot air treatment, ozone treatment, ultraviolet irradiation treatment, oxidation treatment, etc. can be used.

[0047] As the manufacturing method of the resin base material of the present embodiment, there are a casting method by extrusion molding, a uniaxial stretching method, a sequential biaxial stretching method, a simultaneous biaxial stretching method, an inflation method, a tube method, and further, a calendar method, a solution method, etc. Among them, the manufacturing methods by the casting method by extrusion molding, the uniaxial stretching method, the sequential biaxial stretching method, the simultaneous biaxial stretching method, the inflation method, and the tube method can be preferably used, and it can be selected according to the mechanical strength required for the resin base material of the present embodiment.

[0048] The resin base material 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 preferable that at least one layer is a layer having the above-described resin composition because it is easy to exhibit the required mechanical properties.

[0049] <Foam base material> The base material of this embodiment is preferably a foam base material. Thereby, it has excellent adhesion to the adherend, and in particular, it has excellent adhesion while suitably following even an adherend having an uneven shape or a rough surface. The foam structure of the foam base material of the embodiment is preferably a closed-cell structure because it can effectively prevent water from entering from the cut surface of the foam base material. The bubble shape forming the closed-cell structure is not particularly limited, but closed cells having an average bubble diameter in the flow direction and / or the width direction longer than the average bubble diameter in the thickness direction of the foam are preferable because they have appropriate cushioning properties.

[0050] The average bubble diameter in the thickness direction of the foam base material 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 even more preferably in the range of 10 μm to 60 μm. The average bubble diameters in the flow direction and the width direction of the foam base material are 1.2 to 700 μm, preferably 10 to 500 μm, more preferably 50 to 300 μm, and even more preferably 50 to 160 μm. By setting the average bubble diameter within this range, it is easy to form closed cells even when the width of the double-sided tape is narrowed, and the water ingress path from the cross-section of the foam base material can be suitably blocked.

[0051] In the foamed base material of the present embodiment, the ratio of the average bubble diameter is not particularly limited. However, the ratio of the average bubble diameter in the flow direction of the foamed base material to the average bubble diameter in the thickness direction of the foamed base material (average bubble diameter in the flow direction / average bubble diameter in the thickness direction) is preferably 1.2 to 15, more preferably 3 to 8. Also, the ratio of the average bubble diameter in the width direction of the foamed base material to the average bubble diameter in the thickness direction of the foamed base material (average bubble diameter in the width direction / average bubble diameter in the thickness direction) is preferably 1.2 to 15, more preferably 3 to 8. Further, it is more preferable that both the flow direction and the width direction are within the above ratio range. When the ratio is 1.2 or more, it is easy to ensure flexibility in the thickness direction, so the followability is improved. Also, when it is 15 times or less, variations in flexibility and tensile strength in the flow direction and width direction of the foamed base material are less likely to occur.

[0052] Furthermore, the ratio of the average bubble diameter in the flow direction to the average bubble diameter in the width direction is preferably 0.25 to 4 times, more preferably 0.33 to 3 times when the flow direction is taken as 1. When within the above ratio range, variations in flexibility and tensile strength in the flow direction and width direction of the foamed base material are less likely to occur.

[0053] The average bubble diameters in the width direction, flow direction, and thickness direction of the foamed base material are measured as follows. First, the foamed 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) is set at a magnification of 200 times, and the cut surface in the width direction or flow direction of the foamed base material is observed. At this time, the entire length in the thickness direction of the cut surface of the foamed base material is observed. In the observation, the bubble diameters of all the bubbles present in a range of 2 mm in the flow direction or width direction of the cut surface are measured. Next, the 2-mm range is changed, and the bubble diameters of all the bubbles present in any 10 ranges are measured.

[0055] The value obtained by calculating the average value of the bubble diameters measured above is taken as the above average bubble diameter.

[0056] As the foam base material, for example, it is preferable to use one having a 25% compression strength of 20 kPa or more, more preferably one having a compression strength of 30 kPa to 1500 kPa, and even more preferably one having a compression strength of 50 to 1000 kPa in terms of exhibiting a suitable adhesive force with respect to an adherend having an uneven shape or a rough surface. The 25% compression strength was measured in accordance with JIS K6767. Samples cut into 25 squares were stacked until the thickness became about 10 mm. The samples were sandwiched between stainless steel plates having an area larger than the samples, and the strength when the samples were compressed by about 2.5 mm (25% of the original thickness) at a rate of 10 mm / min at 23°C was measured.

[0057] The tensile strengths in the flow direction and the width direction of the foam base material are not particularly limited, but are preferably 500 N / cm 2 or more, more preferably 600 to 1800 N / cm 2 respectively. Also, the tensile strength in the direction with the lower tensile strength among the flow direction and the width direction is preferably 500 to 1400 N / cm 2 and more preferably 600 to 1200 N / cm 2 respectively. The tensile strength in the higher direction at this time is preferably 700 to 1800 N / cm 2 and more preferably 800 to 1600 N / cm 2 respectively. Also, the tensile elongation at the time of cutting in the tensile test is not particularly limited, but the tensile elongation in the flow direction is preferably 200 to 1500%, more preferably 400 to 1000%, even more preferably 620 to 950%, and particularly preferably 450 to 800%. With a foam base material having a tensile strength and a tensile elongation within the above ranges, even if the base material is a foamed and flexible one, deterioration of the processability of the adhesive tape and a decrease in the sticking workability can be suppressed. Also, when peeling the adhesive tape, delamination or tearing of the foam base material hardly occurs, and even when delamination occurs, the ease of peeling of the adhesive tape can be imparted.

[0058] The tensile strength in the flow direction and the width direction of the above-mentioned foam base material was measured according to JIS K6767. It is the maximum strength measured under the measurement conditions of a tensile speed of 300 mm / min in an environment of 23°C and 50% RH using a sample with a gauge length of 2 cm and a width of 1 cm on a tensilon tensile testing machine.

[0059] The apparent density of the foam base material is not particularly limited, but it is easy to adjust the interlayer strength, compressive strength, average bubble diameter, etc. within the above ranges to achieve both impact resistance and excellent adhesion to the adherend. Therefore, it is 0.08 to 0.8 g / cm 3 , preferably 0.1 to 0.7 g / cm 3 , more preferably 0.15 to 0.65 g / cm 3 . The apparent density was measured according to JIS K6767. A foam base material cut into a rectangle of 4 cm × 5 cm was prepared for about 15 cm 3 minutes, and its mass was measured to obtain the apparent density.

[0060] As the foam base material, it is preferable to use one with a thickness of 1500 μm or less, more preferably one with a thickness of 1300 μm or less, and even more preferably one with a thickness of 700 μm or less in order to impart excellent tape processability and excellent followability to the adherend. The lower limit of the thickness is preferably 50 μm. In addition, the foam base material may have other layers as needed. Examples of the other layers include a laminate layer such as a polyester film or a polyolefin film, a light shielding layer, a light reflecting layer, an electric conduction layer or a heat conduction layer such as a metal layer for imparting dimensional stability, good tensile strength, reworkability, etc. of the adhesive tape.

[0061] In this embodiment, the compressive strength or tensile strength of the foam base material can be appropriately adjusted according to the material of the base material to be used or the foam structure. The type of the foam base material of this embodiment is not particularly limited, but an olefin resin foam composed of polyethylene, polypropylene, ethylene-propylene copolymer resin, ethylene-vinyl acetate copolymer polymer, etc.; a polyurethane foam; a rubber foam composed of acrylic rubber or other elastomers, etc. can be used. Among them, it is easy to produce a thin foam base material excellent in followability to the unevenness of the adherend surface, cushioning absorbability, etc., and from the viewpoint of easy recyclability with an olefin resin that is widely used as a thermoplastic resin adherend, an olefin resin foam can be preferably used. The olefin resin is a resin having an olefin monomer unit and can be produced by polymerization of an olefin monomer. 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 derivatives thereof. Among these, from the viewpoints of productivity and cost, ethylene or propylene can be particularly preferably used. Therefore, it is preferable that the base material contains an olefin resin. Further, the olefin resin preferably contains a polyethylene resin or an ethylene-propylene copolymer resin. Note that the olefin resin may 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, still more preferably 90% by mass or more and 98% by mass or less with respect to the total amount (100% by mass) of the foam base material.

[0063] Such a foam substrate is obtained by supplying an olefin resin and a thermal decomposition type foaming agent to an extruder, melt-kneading them, extruding them in a sheet form from the extruder, crosslinking the resulting foaming olefin resin sheet with an electron beam, and then foaming, stretching, and thinning. Examples thereof include crosslinked olefin resin foams. As the olefin resin, conventionally known ones can be used, but those containing 40% by mass or more of a polyethylene resin obtained using a metallocene compound containing a tetravalent transition metal are preferred. Further, after foaming the foam, the foamed sheet may be sliced in the thickness direction and then stretched and skinned with a hot roll for production.

[0064] In order to improve the adhesion to the adhesive layer or other layers, the foam substrate may be subjected to surface treatment such as corona treatment, flame treatment, plasma treatment, hot air treatment, ozone-ultraviolet treatment, or application of an easy-adhesion treatment agent. By setting the wetting index with a wetting reagent to 36 mN / m or more, preferably 40 mN / m or more, good adhesion to the adhesive can be obtained.

[0065] <Other components> Further, in the present embodiment, the foam substrate may contain, as necessary within a range not impairing the properties, other polymer components, crosslinking agents, anti-aging agents, ultraviolet absorbers, fillers, polymerization inhibitors, surface conditioners, antistatic agents, defoaming agents, viscosity regulators, light stabilizers, weather stabilizers, heat stabilizers, antioxidants, leveling agents, organic pigments, inorganic pigments, pigment dispersants, silica beads, organic beads, resin reinforcing agents such as cellulose nanofibers; inorganic fillers such as silicon oxide, aluminum oxide, titanium oxide, zirconia, and antimony trioxide. As the polyolefin resin foam substrate used in the pressure-sensitive adhesive tape of the present invention, 0.1% by mass to 10% by mass, preferably 1% by mass to 7% by mass, is preferred with respect to the polyolefin resin in order to maintain appropriate followability and cushioning properties.

[0066] (Adhesive layer) The pressure-sensitive adhesive layer of the present embodiment can be formed by using a pressure-sensitive adhesive composition. Such a pressure-sensitive adhesive composition constituting the pressure-sensitive adhesive layer is not particularly limited, but those having good adhesion to the substrate can be used. For example, the pressure-sensitive adhesive composition of the present embodiment can be a pressure-sensitive adhesive composition containing one or more pressure-sensitive adhesives selected from the group consisting of acrylic pressure-sensitive adhesives, urethane pressure-sensitive adhesives, rubber pressure-sensitive adhesives, and silicone pressure-sensitive adhesives. Further, in the present embodiment, a pressure-sensitive adhesive composition containing a water-dispersible emulsion-type pressure-sensitive adhesive can also be used. As the pressure-sensitive adhesive composition of the present embodiment, an acrylic pressure-sensitive adhesive composition is preferable because a relatively strong adhesive force can be easily obtained. As the acrylic pressure-sensitive adhesive composition, one or more (meth)acrylic polymers selected from the group consisting of (meth)acrylate homopolymers and copolymers of (meth)acrylate and other monomers are used as a base polymer (a component of the acrylic pressure-sensitive adhesive), and a composition in which additives such as an adhesion-imparting resin or a crosslinking agent are blended as necessary can be preferably used.

[0067] <Acrylic pressure-sensitive adhesive composition> The pressure-sensitive adhesive layer of the present embodiment is preferably formed by using an acrylic pressure-sensitive adhesive composition. The (meth)acrylic polymer, which is the base polymer of the acrylic pressure-sensitive adhesive composition (a component of the acrylic pressure-sensitive adhesive), is not particularly limited. For example, it includes at least one polymer containing a (meth)acrylic acid alkyl ester monomer as a monomer unit. The (meth)acrylic acid alkyl ester monomer is, for example, a (meth)acrylic acid alkyl ester having 2 to 14 carbon atoms in the alkyl group, and is not particularly limited. For example, alkyl (meth)acrylates such as methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, s-butyl (meth)acrylate, t-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 can be used. One or more of these are used. Among them, it is preferable to use a (meth)acrylic acid alkyl ester having 1 to 8 carbon atoms in the alkyl group, particularly n-butyl acrylate or 2-ethylhexyl acrylate, because it is easy to ensure adhesion to the adherend and has excellent cohesive strength. In the present specification, "(meth)acrylic acid alkyl ester" means acrylic acid alkyl ester or methacrylic acid alkyl ester.

[0068] The content of the (meth)acrylic acid alkyl ester monomer unit in the (meth)acrylic polymer is preferably 50 to 98.5% by mass, more preferably 80 to 98.5% by mass, based on all the monomer units constituting the (meth)acrylic polymer. It is preferable to copolymerize the (meth)acrylic polymer with a monomer having a polar group such as a hydroxyl group, a carboxyl group, or an amino group in the side chain, for example, an acrylic acid ester monomer or other vinyl-based monomers. As a result, the structural units derived from these monomers (= monomer units) become crosslinking points in the (meth)acrylic polymer, and it is possible to adjust the hardness of the pressure-sensitive adhesive component and exhibit the desired adhesive strength.

[0069] As the monomer having a hydroxyl group, a vinyl monomer having a hydroxyl group is preferable. For example, hydroxyl group-containing (meth)acrylates 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, and 12-hydroxylauryl (meth)acrylate can be used. The monomer having a hydroxyl group is preferably used in the range of 0.01% by mass to 0.2% by mass, more preferably in the range of 0.01% by mass or more and less than 0.1% by mass, and in the range of 0.02% by mass to 0.08% by mass in terms of setting the tensile strength of the pressure-sensitive adhesive layer within a specific range and obtaining more excellent adhesive strength and holding power. As the monomer having a carboxyl group, a vinyl monomer having a carboxyl group is preferable. Acrylic acid, methacrylic acid, itaconic acid, maleic acid, (meth)acrylic acid dimer, crotonic acid, etc. can be used. Among them, it is preferable to use acrylic acid as a copolymerization component. The content of the monomer having a carboxyl group is not particularly limited as long as the acid value of the (meth)acrylic polymer is within a predetermined preferable range, but it is preferably used in the range of 1% by mass to 30% by mass, more preferably in the range of 1% by mass to 15% by mass, and in the range of 1% by mass to 7% by mass in terms of obtaining more excellent adhesive strength and holding power. Examples of the monomer having an amide group include N-vinylpyrrolidone, N-vinylcaprolactam, acryloylmorpholine, acrylamide, N,N-dimethylacrylamide, etc. Examples of other highly polar vinyl monomers include vinyl acetate, ethylene oxide-modified succinic acid acrylate, and sulfonic acid group-containing monomers such as 2-acrylamido-2-methylpropanesulfonic acid.

[0070] When an isocyanate-based crosslinking agent is blended in the acrylic pressure-sensitive adhesive composition, it is preferable to use a (meth)acrylic polymer copolymerized with a highly polar vinyl monomer having a functional group that reacts with the isocyanate group. As the highly polar vinyl monomer having a functional group that reacts with the isocyanate group, a hydroxyl group-containing vinyl monomer is preferable, and 2-hydroxyethyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and 6-hydroxyhexyl (meth)acrylate are particularly preferable. The content of the hydroxyl group-containing vinyl monomer unit that reacts with the isocyanate-based crosslinking agent is preferably 0.01 to 1.0% by mass, more preferably 0.03 to 0.3% by mass, based on all the monomer units constituting the (meth)acrylic polymer.

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

[0072] 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, in order to balance the coatability and the adhesive physical properties. The weight average molecular weight is in terms of standard polystyrene conversion by gel permeation chromatography (GPC). The measurement conditions of the weight average molecular weight are as described in the column of Examples below. As the pressure-sensitive adhesive layer formed using the (meth)acrylic pressure-sensitive adhesive composition, it is preferable to use one having a gel fraction of 25% by mass to 70% by mass, and more preferably one having a gel fraction of 30% by mass to 60% by mass. When the gel fraction is within the above range, both cohesiveness and adhesiveness are good. The method for calculating the above gel fraction is as described in the column of Examples below.

[0073] <Rubber-based pressure-sensitive adhesive composition> The pressure-sensitive adhesive layer of this embodiment may be formed by using a rubber-based pressure-sensitive adhesive composition. Examples of the rubber-based pressure-sensitive adhesive composition include natural rubber-based polymers such as natural rubber and its modified products, synthetic rubber-based polymers such as butyl rubber and isoprene rubber, and block copolymer rubber-based polymers such as vinyl aromatic block copolymers and acrylic block copolymers. It contains one or more rubber-based pressure-sensitive adhesives, and if necessary, additives such as tackifying resins or crosslinking agents may be blended. Among them, a rubber-based pressure-sensitive adhesive composition containing a block copolymer rubber-based polymer is preferable because it has thermoplasticity and can be melt-kneaded with the resin constituting the adherend during material recycling. Examples of the vinyl aromatic block copolymer include block copolymers of a polymer block composed of an aromatic vinyl compound (for example, styrene, α-methylstyrene) and a polymer block composed of a conjugated diene compound (for example, isoprene, butadiene, ethylene butylene, ethylene propylene, farnesene). Among them, diblock copolymers such as styrene-isoprene copolymer, styrene-butadiene copolymer, styrene-ethylene butylene copolymer, styrene-ethylene propylene copolymer, and triblock copolymers such as styrene-isoprene-styrene copolymer, styrene-butadiene-styrene copolymer, styrene-farnesene-styrene copolymer are preferable. As the acrylic block copolymer, examples include block copolymers of a polymer block composed of a methacrylic acid ester compound (for example, methyl methacrylate (MMA), ethyl methacrylate (EMA)) and a polymer block composed of an acrylic acid ester compound (for example, an (meth)acrylic acid 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, it is preferably one having a weight average molecular weight in the range of 10,000 to 800,000 measured in terms of standard polystyrene using gel permeation chromatography (GPC), and more preferably one in the range of 30,000 to 500,000. As the adhesive layer formed using the rubber-based adhesive composition, it is preferably one having a gel fraction of 0 mass% to 60 mass%, and more preferably one having a gel fraction of 0 mass% to 40 mass%. The rubber-based adhesive composition using a block copolymer rubber-based polymer is particularly preferred because the gel fraction can be designed to be 0%. The calculation method of the gel fraction is as described in the column of Examples below.

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

[0076] As the gum component, those mainly serving as the binder component of the adhesive can be used. For example, polyorganosilicon can be used. As the polyorganosilicon, peroxide-curable polyorganosilicon and addition-curable polyorganosilicon are known, and either can be used. Examples of the addition-curable polyorganosilicon include polyorganosiloxane having a structure in which a polymerizable unsaturated double bond is bonded to a silicon atom. Further, as the polyorganosilicon used as the gum component, the weight average molecular weight measured in terms of standard polystyrene using gel permeation chromatography (GPC) is preferably 150,000 or more, more preferably 150,000 to 1,000,000. As the resin component, those conventionally known can be appropriately selected and used. However, it is preferable to use a relatively low molecular weight polyorganosilicon, and more preferably an addition-curable polyorganosilicon. Further, as the polyorganosilicon used as the resin component, the weight average molecular weight measured in terms of standard polystyrene using gel permeation chromatography (GPC) is preferably 100 to 10,000, more preferably 300 to 8000.

[0077] Further, as the metal catalyst that may be contained in the silicone-based adhesive composition, it is preferable to use, for example, an organometallic catalyst of Group 10 of the periodic table. Specifically, it is more preferable to use a platinum-based catalyst because of its excellent reaction promoting effect. As the adhesive layer formed using the silicone-based adhesive composition, those having a gel fraction of 70% by mass to 99% by mass are preferably used, and those having a gel fraction of 75% by mass to 97% by mass are more preferably used. The method for calculating the gel fraction is as described in the column of the examples below.

[0078] <Crosslinking agent> The pressure-sensitive adhesive composition or pressure-sensitive adhesive layer of this embodiment preferably contains a crosslinking agent in order to increase the cohesive force of the pressure-sensitive adhesive layer. Examples of such crosslinking agents 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 the type that is added after the polymerization is completed to promote the crosslinking reaction is preferred. Isocyanate-based crosslinking agents and epoxy-based crosslinking agents that are highly reactive with (meth)acrylic polymers are preferred. In particular, isocyanate-based crosslinking agents are preferred because they impart adhesive strength, holding power, and adhesion between the substrate and the pressure-sensitive adhesive layer. Furthermore, in the material recycling process, the urethane bond formed between the isocyanate-based crosslinking agent and the hydroxyl group of the pressure-sensitive adhesive resin is appropriately cleaved by thermal decomposition, so that it is preferably compatible with the resin of the adherend or substrate. Examples of the isocyanate-based crosslinking agent include tolylene diisocyanate, naphthylene-1,5-diisocyanate, hexamethylene diisocyanate, diphenylmethane diisocyanate, xylylene diisocyanate, trimethylolpropane-modified tolylene diisocyanate, and the like. Particularly preferred is a trifunctional polyisocyanate-based compound. Examples of the trifunctional isocyanate-based compound include tolylene diisocyanate and its trimethylolpropane adducts, triphenylmethane isocyanate, and the like. In addition, as an index of the degree of crosslinking, the value of the gel fraction, which measures the insoluble matter after immersing the pressure-sensitive adhesive layer in toluene for 24 hours, is used.

[0079] <Adhesion-imparting resin> The pressure-sensitive adhesive composition or pressure-sensitive adhesive layer of this embodiment preferably contains an adhesion-imparting resin in order to improve the adhesive strength of the pressure-sensitive adhesive layer. Examples of the adhesion-imparting resin include rosin-based resins, polymerized rosin-based resins, polymerized rosin ester-based resins, rosin phenol-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, and the like. When used in an emulsion-type pressure-sensitive adhesive composition, it is preferable to use an emulsion-type adhesion-imparting resin. Preferred tackifying resins include disproportionated rosin ester resins, polymerized rosin ester resins, rosin phenol resins, hydrogenated rosin ester resins, and (meth)acrylate resins.

[0080] The softening point of the tackifying resin is not particularly defined, but is 30 to 180°C, preferably 70 to 160°C. Also, one or more tackifying resins may be used. By blending a tackifying resin with a high softening point, high adhesion 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] When using a (meth)acrylic polymer and a tackifying resin, the mixing ratio is preferably such that the content of the tackifying resin with respect to 100 parts by mass of the (meth)acrylic polymer is 5 to 80 parts by mass, more preferably 7 to 70 parts by mass, and even more preferably 10 to 60 parts by mass. By setting the ratio of the two within this range, it becomes easier to ensure adhesion to the adherend. Also, when using a rubber-based pressure-sensitive adhesive composition as the pressure-sensitive adhesive, it is preferable to add 50 to 150 parts by mass of the tackifying resin with respect to 100 parts by mass of the rubber-based pressure-sensitive adhesive. In general, when using a silicone-based pressure-sensitive adhesive as the pressure-sensitive adhesive, no tackifying resin is added.

[0082] <Other Components> Further, the pressure-sensitive adhesive composition or pressure-sensitive adhesive layer of the present embodiment may contain other known and commonly used additives as necessary. Specifically, as additives for the pressure-sensitive adhesive composition, other polymer components, ultraviolet absorbers, fillers, polymerization inhibitors, surface modifiers, antistatic agents, defoaming agents, viscosity modifiers, light stabilizers, weather stabilizers, heat stabilizers, antioxidants, leveling agents, organic pigments, inorganic pigments, pigment dispersants, plasticizers, softeners, flame retardants, metal deactivators, resin strengtheners, organic beads, etc. may be used as necessary within a range that does not impair the properties; those containing inorganic fillers such as silicon oxide, aluminum oxide, titanium oxide, zirconia, antimony pentoxide, etc. can be used. The above-mentioned additive is preferably contained in an amount of 0% by mass or more and 10% by mass or less, more preferably 0% by mass or more and 5% by mass or less, based on the total amount of the adhesive composition or the adhesive layer of the present embodiment. Among them, the adhesive composition or the adhesive layer of the present embodiment preferably contains one or more selected from the group consisting of an antioxidant, an ultraviolet absorber, a heat stabilizer, and a resin strengthening agent. This has the effect of suppressing the strength deterioration of the recycled resin during melt kneading, extrusion molding, or in a high-temperature environment.

[0083] Specific examples of the above-mentioned antioxidant include 2,6-di-t-butyl-4-methylphenol, tetrakis-[methylene-3-(3’,5’-di-t-butyl-4’-hydroxyphenyl)propionate]methane, n-octadecyl-3-(4’-hydroxy-3’,5’-di-t-butylphenyl)propionate, pentaerythritol-tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], 3,9-bis[2-{3-(3-t-butyl-4-hydroxy-5-methylphenyl)propionyloxy}-1,1-dimethylethyl]-2,4,-8,10-tetraoxaspiro[5,5]undecane, and the like. Examples of the above-mentioned ultraviolet absorber 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. Examples of the above-mentioned heat stabilizer include hindered phenol-based compounds, phosphorus-based compounds, lactone-based compounds, hydroxylamine-based compounds, and sulfur-based compounds. Examples of the above-mentioned resin strengthening agent include known materials, preferably fibrous or particulate ones, and 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, but is preferably 5 to 100 μm, more preferably 5 to 75 μm, and even more preferably 10 to 60 μm. Being within this range facilitates the coexistence of adhesiveness and thinning of the tape.

[0085] (Method for manufacturing an adhesive tape) The method for manufacturing the adhesive tape of this embodiment is not particularly limited and can be manufactured by a known method. Specifically, an 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 by the following steps (i) to (ii). (i) By applying an adhesive composition to the surface of a release liner and drying it, etc., an adhesive layer (that is, two release liners with an adhesive formed thereon) is formed on one side of the release liner. At this time, when forming the adhesive layer on the surface of at least one of the release liners, for example, by a gravure printing method, a die coating method, or a comma coating method, a portion where the adhesive is not applied is formed on the release liner, and a non-pasted portion may be formed in the adhesive layer. (ii) Next, the adhesive layer in the state of having the above release liner is bonded to the surface of the prepared base material, and pressure is applied as necessary.

[0086] In addition, the laminated film or the adhesive tape may have a release liner laminated thereon for protecting the adhesive layer as necessary. The release liner is not particularly limited, but for example, a synthetic resin film such as polyethylene, polypropylene, or polyester film, paper, non-woven fabric, cloth, foamed sheet, metal foil, and a material obtained by subjecting at least one side or both sides of a base material such as a laminate thereof to a release treatment such as a silicone-based treatment, a long-chain alkyl-based treatment, or a fluorine-based treatment to enhance the peelability from the adhesive can be used.

[0087] Another aspect of the present disclosure is a component including a thermoplastic resin to which the recyclable adhesive tape of the present embodiment is attached. The component is not particularly defined, and examples thereof include electric and electronic devices / components, OA devices / components, information terminal devices / components, machine parts, household appliances, moving body parts (aircraft parts, railway vehicle parts), vehicle parts (automobile interior and exterior), building members, various containers, leisure goods / groceries, or lighting devices. By the thermoplastic resin contained in the component and the adhesive tape satisfying a specific relational expression (1), the component having the thermoplastic resin can be recycled in a state where it is attached, and there is an effect that the reduction rate of the tensile strength in the recycled plastic material is small.

[0088] As another aspect of the present disclosure, the present disclosure is an electronic device or a moving body formed using a component made of a thermoplastic resin to which the recyclable adhesive tape of the embodiment is attached. The moving body is not particularly limited, and examples thereof include moving bodies such as vehicles, aircraft, ships, bulldozers, excavators, truck cranes, forklifts, etc. And the vehicles include four-wheeled vehicles (passenger cars, trucks, buses, etc.) using gasoline or bioethanol as fuel, electric vehicles using secondary batteries or fuel cells, hybrid vehicles, etc.; two-wheeled motorcycles, bicycles; railway vehicles (trains, hybrid trains, locomotives, bullet trains, linear motor cars, etc.), etc.

Examples

[0089] Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples at all.

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

[0091] (1) Gel fraction (mass%) After laminating the surface of each pressure-sensitive adhesive layer in the pressure-sensitive adhesive tape produced in the examples, which has been subjected to a release treatment with a release liner, and aging it for 2 days in an environment at 40°C, a pressure-sensitive adhesive layer for measuring the gel fraction is formed. A test piece was prepared by cutting the obtained pressure-sensitive adhesive layer into a square with a length of 50 mm and a width of 40 mm. After measuring the mass (G1) of the above test piece, the test piece was immersed in 50 g of toluene for 24 hours in an environment at 23°C, and the mixture of the test piece and toluene after the immersion was filtered using a 300-mesh wire mesh to extract the insoluble component in toluene, and the mass (G2) of the insoluble component dried in an environment at 105°C for 1 hour was measured. Based on the above mass (G1) and mass (G2) and the following formula, the gel fraction was calculated. Gel fraction (mass %) = (G2 / G1) × 100

[0092] (2) The average thickness of the base material, the average thickness (coating thickness) of the pressure-sensitive adhesive layer, and the average thickness of the pressure-sensitive adhesive tape were measured using a Dial Thickness Gauge Model G manufactured by Ozaki Seisakusho (n = 3).

[0093] (3) 25% Compressive strength (kPa) The 25% compressive strength of the base material was measured in accordance with JIS K6767. Specifically, a sample was prepared by cutting the base material used in each example into a 25 mm square. The sample was placed on a stainless steel plate with a larger area than the sample, and at 23°C and 50% RH, the strength was measured when the sample was compressed by 25% of the initial thickness at a speed of 0.5 mm / min using a stainless steel probe with a diameter of 7 mm.

[0094] (4) Polyolefin content in the pressure-sensitive adhesive tape (= content of olefin resin in the pressure-sensitive adhesive tape) X: Mass (g) of the pressure-sensitive adhesive layer × Olefin resin content (%) in the pressure-sensitive adhesive layer / 100 Y: Mass (g) of the base material × Olefin resin content (%) in the base material / 100 Polyolefin content (%) = (X + Y) / Mass (g) of the pressure-sensitive adhesive tape * 100

[0095] (5) Pressure-sensitive adhesive tape content (mass %) The content of the adhesive tape (the content of the adhesive tape in the entire molded product or the entire recycled plastic material) was calculated from the compounding ratio of the adhesive tape with respect to the entire molded product or the entire recycled plastic material.

[0096] (6) Tensile strength (MPa) and tensile strength strain (%) For the molded products (1) to (4) of the multi-purpose test piece type A1 prepared later, a tensile test was conducted using a tensile testing machine (manufactured by Shimadzu Corporation) in accordance with JIS K7161-1 under the measurement conditions of a grip distance of 115 mm, a gauge length of 75 mm, a test speed of 50 mm / min, and 23°C and 50% RH to measure the tensile strength (MPa) and the tensile strength strain (%).

[0097] (7) Bending strength (MPa) and bending strength strain (%) For the molded products (1) to (4) of the multi-purpose test piece type A1 prepared later, a three-point bending test was conducted using a tensile testing machine (manufactured by Shimadzu Corporation) in accordance with JIS K7171 under the measurement conditions of a test speed of 2 mm / min, a lower support distance of 64 mm, and 23°C and 50% RH to measure the bending strength (maximum bending stress, MPa) and the bending strength strain (%).

[0098] (8) Confirmation of the dispersion state of the adhesive tape component in the mixture A PET film (Unitika S-100) with a thickness of 100 μm was laid on the entire upper surface of the iron plate of a hot press machine (TP-750 type manufactured by Tester Sangyo Co., Ltd.), and about 2 g of the pellets of the recycled plastic materials (1) to (4) obtained below were spread and placed in the central part of the PET film so that the pellets did not overlap. Next, the same PET film as before was placed on the pellets, and then pressed at 180°C until it reached a diameter of about 14 cm to create a sheet. The sheet was cut into a 10 cm square, and the presence or absence of foreign matter (poor dispersion of the adhesive tape) was visually confirmed.

[0099] (9) Weight average molecular weight (GPC) of the adhesive resin The weight-average molecular weight defined in this specification is the value measured by gel permeation chromatography (GPC method) and calculated in terms of standard polystyrene. Specifically, the above weight-average molecular weight can be measured under the following conditions using a GPC apparatus (HLC-8320GPC) manufactured by Tosoh Corporation. · Sample concentration: 0.5 mass% (tetrahydrofuran solution) · Sample injection volume: 100 μl · Eluent: Tetrahydrofuran · Flow rate: 0.8 ml / min · Measurement temperature: 40 °C · This column: 2 pieces of TSKgel GMHHR-H(20) · 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 pressure-sensitive adhesive 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 pressure-sensitive adhesive composition The pressure-sensitive adhesive compositions used in the examples were each prepared by the following method. <Preparation Example 1: Pressure-sensitive adhesive composition (P-1)> Into a reaction vessel equipped with a stirrer, a reflux condenser, a nitrogen inlet tube, and a 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 were charged as the monomer composition to be used. While stirring, the temperature was raised to 72 °C while blowing nitrogen. Next, 2 parts by mass (solid content 0.1% by mass) of a 2,2'-azobis(2-methylbutyronitrile) solution previously dissolved in ethyl acetate was added to the above mixture, and after holding at 72 °C for 4 hours with stirring, it was held at 75 °C for 5 hours. The above mixture was diluted with ethyl acetate and filtered through a 200-mesh wire net to obtain a solution (solid content concentration 26%) of an acrylic polymer (A-1) having 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 polymerization rosin ester-based 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 to obtain a tackifier solution having a solid content of 30% by mass. Next, 1.0 part by mass of Barnoc D-40A (manufactured by DIC Corporation, an adduct of tolylene diisocyanate and trimethylolpropane, non-volatile content 40% by mass, hereinafter D-40A) was added as a crosslinking agent to 100 parts by mass of the above tackifier solution, and the mixture was stirred and mixed uniformly to obtain a tackifier composition (P-1). The polyolefin resin content of the said tackifier composition (P-1) (excluding solvent) is 0% by mass.

[0102] <Preparation Example 2: Tackifier Composition (P-2)> A solution (non-volatile content 35% by mass) of an acrylic polymer (A-2) having a weight average molecular weight of 1 million was obtained in the same manner as in Preparation Example 1 except that 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 were changed.

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

[0104] (2-2) Preparation of Adhesive Tape (Example 1: Preparation of Adhesive Tape (1)) The pressure-sensitive adhesive composition (P-1) was applied to the surface of the release liner having a release treatment using a bar coater so that the thickness of the dried pressure-sensitive adhesive layer was 50 μm, and dried at 80°C for 3 minutes to prepare a pressure-sensitive adhesive layer. Next, the pressure-sensitive adhesive layer was attached to both sides of a polypropylene-based foamed substrate with a thickness of 300 μm (apparent density 0.2 g / cm 3 , the polyolefin content of the foamed substrate was 93.4% by mass, and the wettability index was adjusted to 54 mN / m by corona treatment of the surface), and cured in an environment at 40°C for 48 hours to prepare an adhesive tape (1). The properties of the obtained adhesive tape (1) are shown in Table 1 below.

[0105] (Example 2: Preparation of Adhesive Tape (2)) The pressure-sensitive adhesive composition (P-2) was applied to the surface of the release liner using a bar coater so that the thickness of the dried pressure-sensitive adhesive layer was 75 μm, and dried at 80°C for 3 minutes to prepare a pressure-sensitive adhesive layer. Next, the pressure-sensitive adhesive layer was attached to a polyethylene-based foamed substrate having an average thickness of 200 μm (apparent density 0.2 g / cm 3, (with a polyolefin content of 94.9% by mass in the foam base material and the wettability index adjusted to 54 mN / m by corona-treating the surface), was pasted on both sides, and an adhesive tape (2) was produced by curing it in an environment at 40°C for 48 hours. 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 Products (3-1) Preparation of Recycled Plastic Material (1) and Molded Product (1) Using Adhesive Tape (1) To polypropylene resin (J106G manufactured by Prime Polymer Co., Ltd., melting point 160°C, pellets), the adhesive tape (1) obtained above (with the release liner removed) was mixed at a ratio of 1% by mass with respect to the polypropylene resin, and melted and kneaded at 180°C using a twin-screw extruder (manufactured by Technovel Corporation, KZW25) under the conditions of 180°C, kneading speed 350 rpm, screw rotation speed 300 rpm, and discharge speed 5 kg / h to obtain pellets of a recycled plastic material (1) containing 1% by mass of the adhesive tape (1). The pellets of the recycled plastic material (1) obtained above were used to produce a molded product (1) of type A1 of the multi-purpose test piece according to JIS K7139 using an injection molding machine (PNX60III manufactured by Nissei Plastic Industrial Co., Ltd., molding machine temperature 180°C, mold temperature 40°C).

[0108] (3-2) Preparation of Recycled Plastic Material (2) and Molded Product (2) Using Adhesive Tape (1) Pellets of a recycled plastic material (2) and a molded product (2) of type A1 of the multi-purpose test piece according to JIS K7139 were produced in the same manner as the production of the molded product (1) in the column (3-1) above, except that the adhesive tape (1) obtained above (with the release liner removed) was mixed at a ratio of 5% by mass with respect to the polypropylene resin.

[0109] (3-3) Production of Recycled Plastic Material (3) and Molded Product (3) Using Adhesive Tape (2) The adhesive tape (2) obtained above (peel off the release liner) was mixed with polyethylene resin (SHC7260 manufactured by Braskem, softening point 126°C, pellets) at a ratio of 1% by mass based on the polyethylene resin, and melted and kneaded at 146°C using a twin-screw extruder (KZW25 manufactured by Technovel Corporation) heated to 146°C, kneading speed 350 rpm, screw rotation speed 300 rpm, and discharge speed 5 kg / h to obtain pellets of recycled plastic material (3) containing 1% by mass of adhesive tape (2). Pellets of the recycled plastic material (3) obtained above were used to produce a molded product (3) of multi-purpose test piece type A1 of JIS K7139 using an injection molding machine (PNX60III manufactured by Nissei Plastic Industrial Co., Ltd., molding machine temperature 146°C, mold temperature 40°C).

[0110] (3-4) Production of Recycled Plastic Material (4) and Molded Product (4) Using Adhesive Tape (2) A molded product (4) of multi-purpose test piece type A1 of JIS K7139 was produced in the same manner as the production of the molded product (3) in the column of (3-3) above, except that the above adhesive tape (2) (peel off the release liner) was mixed with the polyethylene resin at a ratio of 5% by mass.

[0111] (Reference Example 1: Molded Product (C1) of Thermoplastic Resin (Polypropylene Resin)) A molded product (C1) of multi-purpose test piece type A1 of JIS K7139 was produced using polypropylene resin (J106G manufactured by Prime Polymer Co., Ltd., melting point 160°C, pellets) with an injection molding machine (PNX60III manufactured by Nissei Plastic Industrial Co., Ltd., molding machine temperature 180°C, mold temperature 40°C).

[0112] (Reference Example 2: Molded Product (C2) of Thermoplastic Resin (Polyethylene Resin)) A molded product (C2) of multi-purpose test piece type A1 of JIS K7139 was produced using polyethylene resin (SHC7260 manufactured by Braskem, softening point 126°C, pellets) with an injection molding machine (PNX60III manufactured by Nissei Plastic Industrial Co., Ltd., molding machine temperature 146°C, mold temperature 40°C).

[0113] 4. Ratio of Tensile Strength (σ b / σ a ) and Ratio of Bending Strength (σ d / σ c ) Calculation (4-1) Ratio of Tensile Strength (σ b / σ a ) and Ratio of Bending Strength (σ d / σ c ) Ratio 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 bending 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 bending 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 ratios of the tensile strength ratio (σ b / σ a ) and the bending strength ratio (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 Bending Strength (σ d / σ c ) The characteristics 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 characteristics of Reference Examples (1) and (2), and the ratio of the tensile strength ratio (σ b / σ a ) and the bending strength ratio (σ d / σ c ) of each adhesive tape are shown in Table 2 below.

[0114]

Table 2

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

Industrial Applicability

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

Claims

1. An adhesive tape having a base material and an adhesive layer laminated on at least one surface of the base material, wherein the adhesive tape contains an olefin resin having an olefin monomer unit in an amount of 5% by mass or more and 95% by mass or less based on the total amount (100% by mass) of the adhesive tape, and a recyclable adhesive tape in which an adherend having a 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 prepared by the pressure-sensitive adhesive tape and the thermoplastic resin under the following conditions.) <Production conditions of the test piece> After heating a mixture of the adhesive tape and the thermoplastic resin at a temperature 20°C higher than the melting point of the thermoplastic resin, resin pellets were produced using a twin-screw extruder under the conditions of a kneading speed of 350 rpm, a screw rotation speed of 300 rpm, and a discharge speed of 5 kg / h, and then, using an injection molding machine, a multi-purpose test piece type A conforming to JIS K 7139 was 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 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 strength of the thermoplastic resin, and σ ｄ is the flexural strength of the test piece.)

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

4. The recyclable adhesive tape according to claim 1, wherein the base material contains the olefin resin.

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

6. The recyclable adhesive tape according to claim 1, wherein the base material is a foamed base material.

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 resin.

9. The recyclable adhesive tape according to claim 8, wherein the olefin resin contains 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 based on the total amount of the mixture.

11. The recyclable adhesive tape according to claim 1, containing one or more selected from the group consisting of an antioxidant, an ultraviolet absorber, a heat stabilizer, and a resin strengthener.

12. A component containing a thermoplastic resin to which the recyclable adhesive tape according to claims 1 to 11 is attached.

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

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

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