TW202223022A - Pressure-sensitive adhesive tape - Google Patents

Abstract

The purpose of the present invention is to provide a pressure-sensitive adhesive tape that not only has exceptional flexibility and impact resistance but also imposes a low environmental load. The present invention is a pressure-sensitive adhesive tape having a foam substrate and at least one pressure-sensitive adhesive layer, wherein the foam substrate contains a block copolymer having blocks derived from (meth)acrylic-based monomers, and the pressure-sensitive adhesive tape contains biologically derived carbon.

Description

adhesive tape

The present invention relates to an adhesive tape.

In portable electronic devices such as mobile phones and mobile information terminals (Personal Digital Assistants, PDA), adhesive tapes are used for assembly (for example, Patent Documents 1 and 2). In addition, the adhesive tape is also used for fixing in-vehicle electronic equipment parts such as an in-vehicle panel to a vehicle body. [Prior Art Literature] [Patent Literature]

Patent Document 1: Japanese Patent Laid-Open No. 2009-242541 Patent Document 2: Japanese Patent Laid-Open No. 2009-258274

[The problem to be solved by the invention]

Adhesive tapes for fixing portable electronic equipment parts, vehicle electronic equipment parts, etc. are required to have high adhesive force and impact resistance that does not peel off even if they are impacted. On the other hand, in recent years, portable electronic equipment, electronic equipment for in-vehicle use, and the like tend to be more complicated in shape with higher functions, so there is a need to attach adhesive tapes to steps, corners, non-planar parts, etc. and use. In this case, the adhesive tape is required to have excellent flexibility that can follow the shape of the adherend. However, the conventional adhesive tapes do not fully take into account the impact resistance and flexibility, so an adhesive tape that takes into account impact resistance and flexibility at a higher level is required. In addition, since environmental awareness has increased in recent years, it goes without saying that the function as an adhesive tape requires a product with a lower environmental load.

An object of the present invention is to provide an adhesive tape having excellent flexibility and impact resistance, and also having a low environmental load. [Technical means to solve the problem]

The present invention relates to an adhesive tape, which has a foam base material and at least one adhesive layer, and the foam base material contains a block copolymer, and the block copolymer has a (meth)acrylic monolayer derived from The block of the body, the adhesive tape contains carbon of biological origin. Hereinafter, the present invention will be described in detail.

The adhesive tape of the present invention has a foam base material and at least one adhesive layer. By using the foam base material as the base material of the adhesive tape, the adhesive tape of the present invention can exhibit excellent flexibility and impact resistance. The above-mentioned foam base material may have an open cell structure or a closed cell structure, and preferably has a closed cell structure. The above-mentioned foam base material may have a single-layer structure or a multilayer structure.

The adhesive tape of the present invention contains bio-derived carbon. By using bio-derived materials for the adhesive tape, an adhesive tape with low environmental load can be produced. The above-mentioned bio-derived carbon may be contained in the above-mentioned foam base material or in the above-mentioned adhesive layer, and in the case where the adhesive tape of the present invention has a layer other than the above-mentioned foam base material and the above-mentioned adhesive layer In this case, the foam base material preferably contains bio-derived carbon from the viewpoint of exhibiting excellent flexibility and impact resistance.

The said foam base material contains the block copolymer which has the block derived from a (meth)acrylic-type monomer. By making the said foam base material into the block copolymer which has a block derived from a (meth)acrylic-type monomer, excellent flexibility and impact resistance can be exhibited. Furthermore, by having a block derived from a (meth)acrylic monomer, heat resistance can be imparted to the obtained adhesive tape, and deformation or peeling of the adhesive tape can be suppressed even when exposed to high temperature for a long time.

The above-mentioned block copolymer having a block derived from a (meth)acrylic monomer is not particularly limited as long as it has a block derived from a (meth)acrylic monomer. Among them, those having a block derived from a monomer having a rigid structure (hereinafter, also referred to as a hard block) and those derived from (meth)acrylic acid are preferred in that the flexibility and impact resistance can be further improved. A block copolymer of blocks of monomers.

For block copolymers having a hard block and a block derived from a (meth)acrylic monomer, the two types of blocks are not easily compatible. Inhomogeneous phase-separated structure from the "sea of blocks of (meth)acrylic monomers". In addition, it is considered that by making the above-mentioned islands into pseudo-crosslinking points, rubber elasticity is imparted to the copolymer, and high flexibility and impact resistance can be imparted to the obtained adhesive tape. In addition, it is considered that when a crosslinkable functional group is introduced into the hard block, flexibility and impact resistance can be further imparted to the obtained adhesive tape. The above-mentioned block copolymer having a hard block and a block derived from a (meth)acrylic monomer can adopt any structure such as a diblock structure, a triblock structure, etc., in terms of flexibility and impact resistance. In particular, it is preferable to have a triblock structure having a block derived from a (meth)acrylic monomer between hard blocks. Moreover, the block copolymer which has the said hard block and the block derived from a (meth)acrylic-type monomer may be a graft copolymer. The above-mentioned graft copolymer may be a graft copolymer having a hard block in the side chain and a block derived from a (meth)acrylic monomer in the main chain. As said graft copolymer, a styrene macromonomer-(meth)acrylic monomer copolymer etc. are mentioned, for example.

The above-mentioned hard block is not particularly limited, as long as it has a structure derived from a monomer having a rigid structure, and may be a polymer of a monomer having a single rigid structure, or may be a plurality of monomers containing a rigid structure. A copolymer composed of various monomers. Examples of the above-mentioned monomer having a rigid structure include vinyl aromatic compounds, compounds having a cyclic structure, and short side chain substituents (for example, the number of carbon atoms in the main chain in the side chain substituents is 2 or less) compounds, etc. Moreover, the said hard block may have the structure derived from methyl methacrylate. Among them, it is more preferable that the above-mentioned hard block has a structure derived from a vinyl aromatic compound monomer from the viewpoint of further improving the impact resistance. As said vinyl aromatic compound monomer, styrene, (alpha)-methylstyrene, p-methylstyrene, chlorostyrene, etc. are mentioned, for example. Among them, styrene is preferable in terms of further improving impact resistance. In addition, in this specification, the structure derived from a vinyl aromatic compound monomer means the structure represented by following general formula (1) and (2).

式（1）、（2）中，R ¹表示具有芳香環之取代基。作為取代基R ¹，可例舉：苯基、甲基苯基、氯苯基等。

In formulas (1) and (2), R ¹ represents a substituent having an aromatic ring. As a substituent R1, ^a phenyl group, a methylphenyl group, a chlorophenyl group, etc. are mentioned.

When the above-mentioned block copolymer has the above-mentioned structure derived from the vinyl aromatic compound monomer, the content of the above-mentioned structure derived from the vinyl aromatic compound monomer in the above-mentioned block copolymer is preferably 1% by weight more than 30% by weight or less. By making content of the structure derived from the said vinyl aromatic compound monomer into the said range, flexibility and impact resistance can be improved more. The more preferable lower limit of the content of the above-mentioned structure derived from the vinyl aromatic compound monomer is 1.5% by weight, the further preferable lower limit is 2% by weight, the particularly preferable lower limit is 2.5% by weight, and the more preferable upper limit is 24% by weight, and then A preferable upper limit is 19% by weight, a particularly preferable upper limit is 16% by weight, and a particularly preferable upper limit is 8% by weight.

It is preferable that the said hard block has the structure derived from the monomer which has a crosslinkable functional group. If the hard block has a crosslinkable functional group, the rubber elasticity of the block copolymer is improved by crosslinking, so that the flexibility and impact resistance can be further improved. The above-mentioned cross-linkable functional groups can be cross-linked or not. Even if the uncross-linked structure is maintained, the interaction between the functional groups will improve the cohesion in the block, and improve the flexibility and flexibility. Impact resistance is improved, but preferably cross-linked. In addition, in this specification, the structure derived from the monomer which has a crosslinkable functional group means the structure represented by following general formula (3) and (4).

其中，R ²表示含有至少一個官能基之取代基。作為官能基，例如可例舉：羧基、羥基、環氧基、雙鍵、三鍵、胺基、醯胺基、腈基等。再者，取代基R ²可含有烷基或醚基、羰基、酯基、碳酸酯基、醯胺基、胺酯基（urethane）等作為其構成要素。

Wherein, R ² represents a substituent containing at least one functional group. As a functional group, a carboxyl group, a hydroxyl group, an epoxy group, a double bond, a triple bond, an amino group, an amide group, a nitrile group etc. are mentioned, for example. In addition, the substituent R ² may contain an alkyl group, an ether group, a carbonyl group, an ester group, a carbonate group, an amide group, an urethane group, or the like as its constituents.

The above-mentioned monomer having a crosslinkable functional group is not particularly limited, for example, a monomer containing a carboxyl group, a monomer containing a hydroxyl group, a monomer containing an epoxy group, a monomer containing a double bond, a monomer containing a triple bond monomers, monomers containing amine groups, monomers containing amide groups, monomers containing nitrile groups, etc. Among them, in terms of further improvement of flexibility and impact resistance, it is preferably selected from a monomer containing a hydroxyl group, a monomer containing a carboxyl group, a monomer containing an epoxy group, a monomer containing an amide group, a monomer containing At least one of the group consisting of a double bond monomer and a triple bond-containing monomer. As a hydroxyl group-containing monomer, 4-hydroxybutyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, etc. are mentioned. As said carboxyl group-containing monomer, (meth)acrylic acid etc. are mentioned. As an epoxy group-containing monomer, glycidyl (meth)acrylate etc. are mentioned. As a monomer containing an amide group, (meth)acrylamide etc. are mentioned. As a double bond-containing monomer, allyl (meth)acrylate, hexanediol di(meth)acrylate, etc. are mentioned. As a monomer containing a triple bond, propargyl (meth)acrylate etc. are mentioned. Among them, in terms of being able to impart more excellent flexibility and impact resistance to the adhesive tape, a carboxyl group-containing monomer is preferred, a (meth)acrylic monomer is more preferred, and acrylic acid is further preferred.

When the above-mentioned hard block is a copolymer of the above-mentioned monomer having a rigid structure and the above-mentioned monomer having a crosslinkable functional group, the above-mentioned hard block preferably contains 0.1% by weight or more and 30% by weight or less of the above-mentioned A structure derived from a monomer having a crosslinkable functional group. By making the content of the structure derived from the above-mentioned monomer having a crosslinkable functional group in the above-mentioned hard block within the above-mentioned range, flexibility and impact resistance can be further improved. A more preferable lower limit of the content of the above-mentioned structure derived from a monomer having a crosslinkable functional group is 0.5 wt %, a further preferable lower limit is 1 wt %, and a more preferable upper limit is 25 wt %, and a further preferable upper limit is 20 wt % %.

The (meth)acrylic monomer used as the raw material of the block derived from the (meth)acrylic monomer is not particularly limited, as long as it has flexibility that exhibits rubber elasticity, for example: (meth)acrylic monomer base) methyl acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, amyl (meth)acrylate, hexyl (meth)acrylate, (meth)acrylate Heptyl acrylate, octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, dodecyl (meth)acrylate, ( Lauryl meth)acrylate, isostearyl (meth)acrylate, and the like. Among them, methyl acrylate, ethyl acrylate, butyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate are preferred from the viewpoint of being easy to achieve both heat resistance and flexibility, and more preferred are Methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate. In addition, the said (meth)acrylic-type monomer may be used individually or in combination of several types.

It is preferable that the said (meth)acrylic-type monomer contains the (meth)acrylic-type monomer containing bio-derived carbon. By using a (meth)acrylic-based monomer containing bio-derived carbon, an adhesive tape with a lower environmental load can be produced. Bio-derived carbon contains a certain ratio of radioactive isotopes (C-14), whereas petroleum-derived carbon contains almost no C-14. Therefore, the content rate of the above-mentioned bio-derived carbon can be calculated from the concentration of C-14 contained in the measurement object. Specifically, it can be measured according to ASTM D6866, the standard used in most bioplastics industries.

Examples of the (meth)acrylic-based monomer containing the bio-derived carbon, that is, the (meth)acrylic-based monomer that can be produced from bio-derived raw materials, include, for example, butyl (meth)acrylate, n-heptyl (meth)acrylate, 1-methylheptyl (meth)acrylate, n-octyl (meth)acrylate, lauryl (meth)acrylate, n-stearyl (meth)acrylate, (meth)acrylate base) isostearyl acrylate, behenyl acrylate (behenyl acrylate), isobornyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, and the like. Among them, the above-mentioned (meth)acrylic monomer containing bio-derived carbon is preferably a (methyl) having an alkyl group having 7 to 12 carbons in terms of being able to further improve heat resistance or impact resistance. Acrylic monomers. It is considered that by using such a monomer, the molecular weight between the entanglement points of the polymer becomes relatively large, and the polymer is easily stretched when the adhesive tape is impacted, so that the impact can be alleviated. As the (meth)acrylic monomer having an alkyl group having 7 to 12 carbon atoms, n-heptyl acrylate, 1-methylheptyl acrylate, n-octyl acrylate, lauryl acrylate, methacrylic acid may, for example, be mentioned. Lauryl Ester, Isobornyl Acrylate, etc. Among them, n-heptyl acrylate or n-octyl acrylate is preferable in that it can be used as an adhesive tape with more excellent heat resistance and impact resistance. The (meth)acrylic-type monomer containing the said bio-derived carbon can be used individually or in combination of several types.

It is preferable that the (meth)acrylic-type monomer containing the said bio-derived carbon is a (meth)acrylic-type monomer whose glass transition temperature Tg of a homopolymer is -40 degreeC or less. Impact resistance can be further improved by making "Tg when the (meth)acrylic monomer containing the above-mentioned bio-derived carbon is used as a homopolymer" in the above-mentioned range. The above-mentioned glass transition temperature can be obtained by using the differential expression for "the above-mentioned (meth)acrylic monomer containing bio-derived carbon as a homopolymer having a weight average molecular weight of 100,000 to 1,000,000" A scanning calorimeter (for example, 220C manufactured by Seiko Instruments, etc.) is used for measurement in the atmosphere at a temperature increase rate of 10°C/min. In addition, the said glass transition temperature can be adjusted according to the kind of (meth)acrylic-type monomer. As a (meth)acrylic-type monomer containing bio-derived carbon which satisfies the said Tg, n-heptyl acrylate, n-octyl acrylate, lauryl methacrylate, etc. are mentioned.

The above-mentioned block derived from the (meth)acrylic monomer can use monomers other than the (meth)acrylic monomer within the range where the effect of the present invention is not lost.

It is preferable that the said block copolymer contains 1 weight% or more and 40 weight% or less of the said hard block. By making content of the said hard block into the said range, the foam base material excellent in flexibility, impact resistance, and heat resistance can be formed. From the viewpoint of further improving flexibility, impact resistance and heat resistance, the more preferable lower limit of the content of the hard block is 2 wt %, the more preferable lower limit is 2.5 wt %, and the particularly preferable lower limit is 3 wt %, and The more preferred upper limit is 35% by weight, the more preferred upper limit is 30% by weight, the more preferred upper limit is 26% by weight, the more preferred upper limit is 20% by weight, the particularly preferred upper limit is 17% by weight, and the particularly preferred upper limit is 8% by weight %.

The weight average molecular weight of the above-mentioned block copolymer is preferably 50,000 to 800,000. By making the weight average molecular weight of the block copolymer within the above-mentioned range, flexibility, impact resistance, and heat resistance can be further improved. A more preferable lower limit of the weight average molecular weight of the above-mentioned block copolymer is 75,000, and a more preferable upper limit is 600,000. In addition, the above-mentioned weight-average molecular weight can be measured, for example, by the GPC method, using "2690 Separations Module" manufactured by Waters Corporation as a measuring apparatus, using "GPC KF-806L" manufactured by Showa Denko Corporation as a column, and using ethyl acetate. The ester was used as a solvent, and the above weight average molecular weight was measured under the conditions of a sample flow rate of 1 mL/min and a column temperature of 40°C.

As a method for obtaining the above-mentioned block copolymer, a method in which the raw material monomers of the hard block and the block derived from the (meth)acrylic monomer are freed separately in the presence of a polymerization initiator can be exemplified. A hard block and a block derived from a (meth)acrylic monomer are obtained by reacting the radicals, and then the two are reacted. Moreover, after obtaining a hard block by the said method, the raw material monomer derived from the block of a (meth)acrylic-type monomer is continuously added, and it can also be copolymerized. The method for carrying out the above-mentioned radical reaction, that is, the polymerization method, can be a conventionally known method, for example, solution polymerization (boiling point polymerization or isothermal polymerization), emulsion polymerization, suspension polymerization, block polymerization, and the like.

The above-mentioned foam base material may also contain additives such as antistatic agents, mold release agents, antioxidants, weathering agents, and crystal nucleating agents, or resin modifiers such as polyolefins, polyesters, polyamides, and elastomers.

The above-mentioned foam base material preferably has an apparent density of 0.3 g/cm ³ or more and 0.95 g/cm ³ or less. By making the apparent density of the said foam base material into the said range, intensity|strength can be maintained, and it can be set as an adhesive tape which is more excellent in flexibility and impact resistance. From the viewpoint of further improving the strength, flexibility, and impact resistance of the adhesive tape, the more preferable lower limit of the above-mentioned foam base material is 0.33 g/cm ³ , the more preferable upper limit is 0.9 g/cm ³ , and the more preferable The lower limit is 0.35 g/cm ³ , and the more preferable upper limit is 0.88 g/cm ³ . In addition, the said apparent density can be measured using an electronic hydrometer (for example, "ED120T" by Mirage Corporation) based on JIS K 7222.

It is preferable that the said foam base material has a gel fraction of 90% or less. By making the gel fraction of the said foam base material into the said range, the impact resistance of the adhesive tape obtained can be improved more. From the viewpoint of further improving the impact resistance of the adhesive tape, the more preferable upper limit of the gel fraction is 85%, and the more preferable upper limit is 80%. The lower limit of the gel fraction is not particularly limited, but is, for example, 10% or more, especially 20% or more, especially 35% or more. The above-mentioned gel fraction can be adjusted by crosslinking at least one of the above-mentioned hard block and the above-mentioned (meth)acrylic monomer-derived block. In addition, the said gel fraction can be measured by the following method. Only 0.1 g of the foam base material was taken out from the obtained adhesive tape, immersed in 50 ml of ethyl acetate, and shaken for 24 hours at a temperature of 23 degrees and 120 rpm using a shaker. After shaking, a metal mesh (pore size #200 mesh) was used to separate the ethyl acetate from the foam substrate swelled by absorbing ethyl acetate. The separated foam substrate was dried at 110°C for 1 hour. The weight of the foam base material containing the metal mesh after drying was measured, and the gel fraction of the foam base material was calculated using the following formula. Gel fraction (wt%)=100×(W1-W2)/W0 (W0: initial weight of foam substrate; W1: weight of foam substrate including metal mesh after drying; W2: initial weight of metal mesh)

It is preferable that the said foam base material has a crosslinked structure formed between the main chains of the resin which comprises the said foam base material by adding a crosslinking agent. By forming a cross-linked structure between the main chains of the resin constituting the foam base material, the intermittently applied peeling stress can be dispersed, and the heat resistance and impact resistance of the adhesive tape can be further improved. The said crosslinking agent is not specifically limited, According to the functional group which the resin which comprises the said foam base material has, it can select suitably. Specifically, an isocyanate type crosslinking agent, an aziridine type crosslinking agent, an epoxy type crosslinking agent, a metal chelate type crosslinking agent, etc. are mentioned, for example. Among them, an epoxy-based crosslinking agent or an isocyanate-based crosslinking agent is preferable in terms of being able to crosslink a resin having an alcoholic hydroxyl group or a carboxyl group that can further improve flexibility and impact resistance. In addition, the said isocyanate type crosslinking agent crosslinks between "the alcoholic hydroxyl group or carboxyl group in the resin which comprises the said foam base material" and "the isocyanate group of the crosslinking agent". Moreover, the said epoxy-type crosslinking agent bridge|crosslinks between "the carboxyl group in the resin which comprises the said foam base material" and "the epoxy group of the crosslinking agent". The addition amount of the crosslinking agent is preferably 0.01 part by weight or more and 10 parts by weight or less, more preferably 0.1 part by weight or more and 7 parts by weight or less, relative to 100 parts by weight of the resin that is the main component of the foam base material. .

The foam base material preferably has an average cell diameter of 80 μm or less. By making the average cell diameter of the foam base material within the above-mentioned range, the balance of strength, flexibility and impact resistance of the obtained adhesive tape can be further improved. The average cell diameter of the foam base material is more preferably 60 μm or less, and still more preferably 55 μm or less. The lower limit of the average cell diameter of the foam base material is not particularly limited, but from the viewpoint of securing the flexibility of the tape, it is preferably 20 μm or more, more preferably 30 μm or more. In addition, the said average bubble diameter can be measured by the following method. First, the foam base material was cut into a square of 50 mm, and after being immersed in liquid nitrogen for 1 minute, cutting was performed on a surface perpendicular to the thickness direction of the foam base material using a razor blade. Then, use a digital microscope (such as "VHX-900" manufactured by Keynes Corporation) to take a magnified photo of the cut surface at a magnification of 200 times, and determine the longest cell for all cells existing in the range of thickness × 2 mm. Diameter (Bubble Diameter). This operation was repeated 5 times, and the average cell diameter was calculated by averaging all the obtained cell diameters.

The thickness of the above-mentioned foam substrate is not particularly limited, and a preferred lower limit is 40 μm, and a preferred upper limit is 2900 μm. By making the thickness of the said foam base material into the said range, the adhesive tape of this invention can be suitably used for fixing a portable electronic device part, an in-vehicle electronic device part, or the like. From the viewpoint of being able to be more suitably used for fixing the above-mentioned parts, etc., the preferred lower limit of the thickness of the above-mentioned foam base material is 60 μm, the more preferred upper limit is 1900 μm, and the more preferred lower limit is 80 μm, and more preferably The upper limit is 1400 μm, the lower limit of the particularly preferred is 100 μm, and the upper limit of the particularly preferred is 1000 μm.

The said foam base material should just have a cell structure, and the manufacturing method is not specifically limited. As a manufacturing method, the method of manufacturing the said foam base material by the effect|action of a foaming gas, or the method of mixing a hollow ball in a raw material matrix is mentioned, for example. Among them, the foam produced by the latter method is called a composite microsphere foam, and the above-mentioned foam base material is preferably a composite microsphere foam in terms of better impact resistance and heat resistance. By making the foam base material into a composite microsphere foam material, an independent cell type foam body with a uniform size distribution of foam cells can be obtained, so the overall density of the foam base material becomes more constant and can be more stable. Improve impact resistance. In addition, compared with other foams, the composite microsphere foam is less prone to irreversible disintegration under high temperature and high pressure, and thus exhibits higher heat resistance. The composite microsphere foam material includes those having a foamed structure composed of hollow inorganic particles and those having a foamed structure composed of hollow organic particles. From the viewpoint of flexibility, those having a foamed structure composed of hollow organic particles are preferred. A foamed structure composed of organic particles.

As said hollow organic fine particle, Expancel DU series (manufactured by Japan Fillite Co., Ltd.), Advancell EM series (manufactured by Sekisui Chemical Industry Co., Ltd.), etc. are mentioned, for example. Among them, Expancel 461-20 (average cell diameter after foaming under optimum conditions is 20 μm), Expancel 461-20 is preferable in that it is easy to design the cell diameter after foaming to a range with a higher effect. 461-40 (average cell diameter after foaming under optimum conditions is 40 μm), Expancel 043-80 (average cell diameter after foaming under optimum conditions is 80 μm), Advancell EML101 (under optimum conditions) The average cell diameter after foaming was 50 μm).

When the above-mentioned foam base material is composed of a foam other than the above-mentioned composite microsphere foam, the foaming agent is not particularly limited, and conventionally known foaming agents such as thermally decomposable foaming agents can be used.

The above-mentioned adhesive layer is not particularly limited, and examples thereof include an acrylic adhesive layer, a rubber-based adhesive layer, a urethane adhesive layer, a polysiloxane-based adhesive layer, and the like. Among them, an acrylic pressure-sensitive adhesive layer containing an acrylic copolymer is preferable because it is excellent in heat resistance and can be adhered to a wide variety of adherends.

From the viewpoint of improving the ease of attachment at low temperature due to an increase in initial viscosity, the acrylic copolymer constituting the above-mentioned acrylic adhesive layer is preferably made of butyl acrylate and/or 2-ethylhexyl acrylate. It is obtained by copolymerizing a monomer mixture. Among them, it is more preferable to copolymerize a monomer mixture containing butyl acrylate and 2-ethylhexyl acrylate. That is, a copolymer having a structural unit derived from butyl acrylate and/or a structural unit derived from 2-ethylhexyl acrylate is preferred, and it is more preferred to have a structural unit derived from butyl acrylate and a structural unit derived from 2-ethyl acrylate - Copolymers of structural units of ethylhexyl ester.

Moreover, it is preferable that the said acrylic copolymer is obtained by copolymerizing the (meth)acrylic-type monomer mixture containing bio-derived carbon from the viewpoint of being able to make an adhesive tape with a lower environmental load. As the (meth)acrylic monomer containing the above-mentioned bio-derived carbon, butyl acrylate, n-heptyl acrylate, 1-methylheptyl acrylate, n-octyl acrylate, and lauryl methacrylate are particularly preferred.

The preferable lower limit of the content of the above-mentioned butyl acrylate in the total monomer mixture is 40% by weight, and the preferable upper limit is 80% by weight. That is, the preferable lower limit of the content of the structural unit derived from the said butyl acrylate in the said acrylic copolymer is 40 weight%, and a preferable upper limit is 80 weight%. By making the content of the above-mentioned butyl acrylate within the above-mentioned range, both high adhesive force and viscosity can be achieved.

The preferred lower limit of the content of the above-mentioned 2-ethylhexyl acrylate in the total monomer mixture is 10% by weight, the preferred upper limit is 100% by weight, the more preferred lower limit is 30% by weight, and the more preferred upper limit is 80% by weight , and a further preferred lower limit is 50 wt %, and a further preferred upper limit is 60 wt %. That is, the preferred lower limit of the content of the structural unit derived from the above-mentioned 2-ethylhexyl acrylate in the above-mentioned acrylic copolymer is 10% by weight, the preferred upper limit is 100% by weight, the more preferred lower limit is 30% by weight, and the more preferred upper limit is It is 80 weight%, and a more preferable lower limit is 50 weight%, and a more preferable upper limit is 60 weight%. By making content of the said 2-ethylhexyl acrylate in the said range, high adhesive force can be exhibited.

A preferable lower limit of the content of the above-mentioned bio-derived carbon-containing n-heptyl acrylate in the total monomer mixture is 25% by weight, and a preferable upper limit is 100% by weight. That is, the preferable lower limit of the content of the structural unit derived from the above-mentioned bio-derived carbon-containing n-heptyl acrylate in the acrylic copolymer is 25% by weight, and the preferable upper limit is 100% by weight. The better lower limit of the content of the structural unit derived from the above-mentioned n-heptyl acrylate is 48% by weight, and then the better lower limit is 50% by weight, and the further better lower limit is 60% by weight, and the further better lower limit is 70% by weight, and further The preferred lower limit is 80% by weight. The upper limit of the content of the structural unit derived from the above-mentioned n-heptyl acrylate is not particularly limited, and may be 100% by weight, because it is preferable that the above-mentioned acrylic copolymer also has structural units derived from a monomer having a crosslinkable functional group, etc. Therefore, the preferred upper limit is 99% by weight, and the more preferred upper limit is 97% by weight.

The preferable lower limit of the content of the above-mentioned bio-derived carbon (meth)acrylic monomer in the total monomer mixture is 50% by weight, the preferable upper limit is 100% by weight, and the more preferable lower limit is 80% by weight. , and the better upper limit is 98% by weight. That is, the preferable lower limit of the content of the structural unit derived from the above-mentioned (meth)acrylic-based monomer including the bio-derived carbon in the above-mentioned acrylic copolymer is 50% by weight, the preferable upper limit is 100% by weight, and the more preferable lower limit is It is 80 weight%, and a more preferable upper limit is 98 weight%. By making content of the (meth)acrylic-type monomer containing the said bio-derived carbon in the said range, it becomes possible to achieve both high adhesive force and reduction of an environmental load.

The above-mentioned monomer mixture may also contain other copolymerizable monomers other than butyl acrylate and 2-ethylhexyl acrylate as required. As said other polymerizable monomer which can be copolymerized, the C1-C18 alkyl (meth)acrylate of an alkyl group, a functional monomer, etc. are mentioned, for example. Examples of alkyl (meth)acrylates having 1 to 18 carbon atoms in the alkyl group include methyl (meth)acrylate, ethyl (meth)acrylate, and n-propyl (meth)acrylate. , (meth) isopropyl acrylate, tridecyl methacrylate, (meth) stearyl acrylate, etc. As said functional monomer, for example, hydroxyalkyl (meth)acrylate, glycerol dimethacrylate, glycidyl (meth)acrylate, 2-methacryloyloxyethyl isocyanate, (Meth)acrylic acid, itaconic acid, maleic anhydride, crotonic acid, maleic acid, fumaric acid, and the like.

In order to obtain the above-mentioned acrylic copolymer by copolymerizing the above-mentioned monomer mixture, the above-mentioned monomer mixture may be subjected to a radical reaction in the presence of a polymerization initiator. As a method for radically reacting the above-mentioned monomer mixture, that is, a polymerization method, a conventionally known method can be used, for example, solution polymerization (boiling point polymerization or isothermal polymerization), emulsion polymerization, suspension polymerization, block polymerization, and the like.

The preferable lower limit of the weight average molecular weight (Mw) of the above-mentioned acrylic copolymer is 400,000, and the preferable upper limit is 1.5 million. By making the weight average molecular weight of the said acrylic copolymer into the said range, high adhesive force can be exhibited. From the viewpoint of further improvement of the adhesive force, a more preferable lower limit of the above-mentioned weight average molecular weight is 500,000, and a more preferable upper limit is 1,400,000. In addition, the weight average molecular weight (Mw) means the weight average molecular weight in terms of standard polystyrene obtained by GPC (Gel Permeation Chromatography: Gel Permeation Chromatography).

The preferable upper limit of the ratio (Mw/Mn) of the weight-average molecular weight (Mw) to the number-average molecular weight (Mn) of the acrylic copolymer is 10.0. When Mw/Mn is 10.0 or less, the ratio of low molecular components is suppressed, the adhesive layer is softened at high temperature, and the decrease in bulk strength and adhesive strength is suppressed. From the same viewpoint, the more preferable upper limit of Mw/Mn is 5.0, and the more preferable upper limit is 3.0.

The above-mentioned adhesive layer may contain an adhesion-imparting resin. Examples of the adhesion-imparting resins include rosin ester-based resins, hydrogenated rosin-based resins, terpene-based resins, terpenephenol-based resins, benzofuran-indene-based resins, and alicyclic saturated hydrocarbons. series resin, C5 series petroleum resin, C9 series petroleum resin, C5-C9 copolymer series petroleum resin, etc. These adhesion-imparting resins may be used alone or in combination of two or more.

The content of the adhesion-imparting resin is not particularly limited. With respect to 100 parts by weight of the resin (eg, acrylic copolymer) that is the main component of the adhesive layer, the lower limit is preferably 10 parts by weight, and the upper limit is preferably 60 parts by weight. If the content of the adhesion-imparting resin is 10 parts by weight or more, it is possible to suppress a decrease in the adhesive force of the adhesive layer. If the content of the adhesion-imparting resin is 60 parts by weight or less, it is possible to suppress a decrease in adhesive force or viscosity due to the hardening of the adhesive layer.

The adhesive layer preferably has a cross-linked structure formed between the main chains of the resin (for example, the acrylic copolymer, the adhesion-imparting resin, etc.) constituting the adhesive layer by adding a cross-linking agent. The said crosslinking agent is not specifically limited, For example, an isocyanate type crosslinking agent, an aziridine type crosslinking agent, an epoxy type crosslinking agent, a metal chelate type crosslinking agent, etc. are mentioned. Among them, an isocyanate-based crosslinking agent is preferred. By adding an isocyanate-based cross-linking agent to the above-mentioned adhesive layer, the isocyanate group of the isocyanate-based cross-linking agent and the alcohol in the resin (for example, the above-mentioned acrylic copolymer, the above-mentioned adhesion-imparting resin, etc.) constituting the above-mentioned adhesive layer are formed. The reactive hydroxyl groups react to crosslink the above-mentioned adhesive layer. If a crosslinked structure is formed between the main chains of the resin constituting the adhesive layer, the adhesive layer can disperse the intermittently applied peeling stress, and the adhesive force of the adhesive tape can be further improved. The addition amount of the crosslinking agent is preferably 0.01 to 10 parts by weight, more preferably 0.1 to 7 parts by weight, relative to 100 parts by weight of the resin (eg, the above-mentioned acrylic copolymer) that is the main component of the above-mentioned adhesive layer.

In order to improve the adhesive force, the above-mentioned adhesive layer may also contain a silane coupling agent. The said silane coupling agent is not specifically limited, For example, epoxy silanes, acrylic silanes, methacrylic silanes, amino silanes, isocyanate silanes, etc. are mentioned.

In order to provide light-shielding property, the said adhesive bond layer may contain a coloring material. The said coloring material is not specifically limited, For example, carbon black, aniline black, titanium oxide, etc. are mentioned. Among them, carbon black is preferable in terms of relatively low price and chemical stability. The above-mentioned adhesive layer may optionally contain inorganic fine particles, conductive fine particles, antioxidants, foaming agents, organic fillers, inorganic fillers, and other previously known fine particles and additives.

The thickness of the above-mentioned adhesive layer is not particularly limited, a preferable lower limit is 0.01 mm, and a preferable upper limit is 0.1 mm. By making the thickness of the said adhesive layer into the said range, the adhesive tape of this invention can be suitably used for fixing portable electronic equipment parts, vehicle electronic equipment parts, etc.. The lower limit of the thickness of the above-mentioned adhesive layer is more preferably 0.015 mm, and the more preferable upper limit is 0.09 mm, from the viewpoint of being more suitable for fixing the above-mentioned parts and the like.

The adhesive tape of the present invention may have a resin layer on at least one side of the foam base material. By having the above-mentioned resin layer, the strength of the obtained adhesive tape is improved, so that the impact resistance can be further improved, and especially the durability (rollability) when repeated impact is applied can be improved. The resin layer may be formed on one side of the foam base material, or may be formed on both sides, and is preferably formed on one side of the foam base material.

It is preferable that the resin which comprises the said resin layer has heat resistance. Examples of the heat-resistant resin constituting the resin layer include polyester-based resins such as polyethylene terephthalate, acrylic-based resins, polysiloxane resins, phenol resins, polyimide, and polycarbonate. esters, etc. Among them, an acrylic resin and a polyester-based resin are preferable, and polyethylene terephthalate is more preferable in that an adhesive tape excellent in flexibility can be obtained.

The above-mentioned resin layer may be colored. By coloring the above-mentioned resin layer, light-shielding properties can be imparted to the adhesive tape. The method of coloring the above-mentioned resin layer is not particularly limited, for example, a method of kneading particles or fine bubbles such as carbon black and titanium oxide into the resin constituting the above-mentioned resin layer; a method of applying ink on the surface of the above-mentioned resin layer. method etc.

The resin layer may optionally contain inorganic fine particles, conductive fine particles, plasticizers, adhesion imparting agents, ultraviolet absorbers, antioxidants, foaming agents, organic fillers, inorganic fillers and other previously known fine particles and additives.

The thickness of the resin layer is not particularly limited, and a preferred lower limit is 5 μm, and a preferred upper limit is 100 μm. By making the thickness of the said resin layer into the said range, the handleability and impact resistance of an adhesive tape can be compatible. From the viewpoint of further balancing handleability and impact resistance, a more preferable lower limit of the thickness of the resin layer is 10 μm, and a more preferable upper limit is 70 μm.

The adhesive tape of the present invention may optionally have other layers other than the above-mentioned foam base material and the above-mentioned adhesive layer.

In the adhesive tape of the present invention, it is preferable that the ratio of the thickness of the adhesive layer to the thickness of the foam substrate (thickness of the adhesive layer/thickness of the foam substrate) is 0.1 or more and 2 or less. By setting the ratio of the thickness of the adhesive layer to the foam base material within the above-mentioned range, the strength of the entire adhesive tape obtained is improved, so that the impact resistance can be further improved. The ratio of the thickness of the above-mentioned adhesive layer to the thickness of the foam base material is more preferably 0.15 or more, and more preferably 1.2 or less. Furthermore, the thickness of the above-mentioned adhesive layer refers to the total thickness of the adhesive layers on both sides.

The thickness of the adhesive tape of the present invention is not particularly limited, the lower limit is preferably 0.04 mm, the lower limit is more preferably 0.05 mm, the upper limit is preferably 2 mm, and the upper limit is preferably 1.5 mm. By making the thickness of the adhesive tape of this invention into the said range, the adhesive tape excellent in handleability can be produced.

In the adhesive tape of the present invention, the content of bio-derived carbon is preferably 10% by weight or more. Bio-derived carbon content of 10% by weight or more is the standard for "bio-based products". By setting the content of bio-derived carbon in the adhesive tape of the present invention to 10% by weight or more, it is possible to produce an adhesive tape with a lower environmental load from the viewpoint of saving oil resources or reducing carbon dioxide emissions. . A more preferable lower limit of the content of the above-mentioned biomass-derived carbon is 20% by weight or more, a further preferable lower limit is 40% by weight, a further more preferable lower limit is 50% by weight, and a further preferable lower limit is 60% by weight. The upper limit of the content rate of the above-mentioned biomass-derived carbon is not particularly limited, and may be 100% by weight. Wherein, the content of bio-derived carbon in the above-mentioned foam base material is more preferably 50 wt % or more, and the content of bio-derived carbon in the above-mentioned block copolymer is preferably 40 wt % or more, and more preferably 50 wt % or more % by weight or more.

The manufacturing method of the adhesive tape of this invention is not specifically limited, For example, the following method can be mentioned. First, an adhesive agent solution is apply|coated to a mold release film, it is made to dry, an adhesive agent layer is formed, and a 2nd adhesive agent layer is formed by the same method. Next, an unfoamed body base material is manufactured by the said method, and the said resin layer is laminated|stacked on the said unfoamed body base material, and the laminated body is formed. Then, the obtained adhesive layer was bonded to both surfaces of the obtained laminated body, and it heated, and the unfoamed base material was foamed, and the adhesive tape was manufactured.

The shape of the adhesive tape of the present invention is not particularly limited, and examples thereof include a rectangle, a frame, a circle, an ellipse, a circular ring, and the like.

The adhesive tape of the present invention can exhibit excellent flexibility and impact resistance by using the above-mentioned block copolymer as a foam base material. On the other hand, as a result of studies by the present inventors, it was found that the foam base material contains a copolymer containing the structure derived from the above-mentioned vinyl aromatic compound monomer and the structure derived from the above-mentioned (meth)acrylic monomer. In the case of materials, even if it is a random copolymer, excellent flexibility, impact resistance and heat resistance can be exhibited. It is considered that the reason may be that the same interaction as the above-mentioned phase separation structure is exerted on an extremely small scale such as the nanoscale or the molecular scale. In addition, in this specification, the structure derived from a (meth)acrylic-type monomer means the structure represented by following general formula (5), (6).

其中，R ³表示側鏈。作為側鏈R ³，可例舉：甲基、乙基、丙基、丁基、戊基、己基、庚基、辛基、2-乙基己基、壬基、癸基、十二烷基、月桂基、異硬脂基等。

Wherein, R ³ represents a side chain. As side chain R ³ , methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, 2-ethylhexyl, nonyl, decyl, dodecyl, Lauryl, isostearyl, etc.

Also, the following adhesive tape (hereinafter, referred to as the adhesive tape containing the copolymer) is also one of the present invention, and the adhesive tape has this foam base material and at least one adhesive layer, and the above-mentioned foam base material It contains a copolymer having a structure derived from a vinyl aromatic compound monomer and a structure derived from a (meth)acrylic monomer, and the adhesive tape contains bio-derived carbon.

The above-mentioned copolymer is not particularly limited, and may be a random copolymer or a graft polymer.

As the above-mentioned vinyl aromatic compound monomer and the above-mentioned (meth)acrylic monomer, the same ones as those of the above-mentioned block copolymer can be used.

The above-mentioned copolymer preferably contains 1% by weight or more of the structure derived from the above-mentioned vinyl aromatic compound monomer, more preferably 2% by weight or more, more preferably 5% by weight or more, and preferably 30% by weight or more. % by weight or less, more preferably 19% by weight or less, still more preferably 15% by weight or less, still more preferably 10% by weight or less.

The above-mentioned copolymer preferably contains 70% by weight or more of the structure derived from the above-mentioned (meth)acrylic monomer, more preferably 81% by weight or more, preferably 99% by weight or less, and more preferably 98% by weight. % by weight or less.

The above-mentioned copolymer preferably has a structure derived from a monomer having a crosslinkable functional group. If the above-mentioned copolymer has a crosslinkable functional group, the rubber elasticity of the copolymer is improved by crosslinking or interaction between the functional groups, so that the flexibility and impact resistance can be further improved. The above-mentioned cross-linkable functional groups can be cross-linked or not. Even if the uncross-linked structure is maintained, the interaction between the functional groups will improve the cohesion and enhance the flexibility and impact resistance. , but more preferably cross-linked. In addition, in this specification, the structure derived from the monomer which has a crosslinkable functional group means the structure represented by following general formula (3) and (4).

其中，R ²表示包含至少一個官能基之取代基。作為官能基，例如可例舉：羧基、羥基、環氧基、雙鍵、三鍵、胺基、醯胺基、腈基等。再者，取代基R ²可含有烷基或醚基、羰基、酯基、碳酸酯基、醯胺基、胺酯基等作為其構成要素。

wherein, R ² represents a substituent containing at least one functional group. As a functional group, a carboxyl group, a hydroxyl group, an epoxy group, a double bond, a triple bond, an amino group, an amide group, a nitrile group etc. are mentioned, for example. Furthermore, the substituent R ² may contain an alkyl group, an ether group, a carbonyl group, an ester group, a carbonate group, an amide group, an amine ester group, or the like as its constituents.

The above-mentioned monomer having a crosslinkable functional group is not particularly limited, for example, a monomer containing a carboxyl group, a monomer containing a hydroxyl group, a monomer containing an epoxy group, a monomer containing a double bond, a monomer containing a triple bond monomers, monomers containing amine groups, monomers containing amide groups, monomers containing nitrile groups, etc. Among them, in terms of further improvement of flexibility and impact resistance, it is preferably selected from a monomer containing a hydroxyl group, a monomer containing a carboxyl group, a monomer containing an epoxy group, a monomer containing an amide group, a monomer containing At least one of the group consisting of a double bond monomer and a triple bond-containing monomer. As a hydroxyl group-containing monomer, 4-hydroxybutyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, etc. are mentioned. As said carboxyl group-containing monomer, (meth)acrylic acid etc. are mentioned. As an epoxy group-containing monomer, glycidyl (meth)acrylate etc. are mentioned. As a monomer containing an amide group, (meth)acrylamide etc. are mentioned. As a double bond-containing monomer, allyl (meth)acrylate, hexanediol di(meth)acrylate, etc. are mentioned. As a monomer containing a triple bond, propargyl (meth)acrylate etc. are mentioned. Among them, in terms of being able to impart more excellent flexibility and impact resistance to the adhesive tape, a carboxyl group-containing monomer is preferred, a (meth)acrylic monomer is more preferred, and acrylic acid is further preferred.

The copolymer preferably has a structure derived from the monomer having a crosslinkable functional group in an amount of 0.1% by weight or more and 30% by weight or less. When the content of the structure derived from the monomer having a crosslinkable functional group in the copolymer is within the above range, flexibility and impact resistance can be further improved. A more preferable lower limit of the content of the above-mentioned structure derived from a monomer having a crosslinkable functional group is 0.5 wt %, a further preferable lower limit is 1 wt %, and a more preferable upper limit is 20 wt %, and a further preferable upper limit is 10 wt % %.

As a method for producing the above-mentioned copolymer, for example, a solution obtained by mixing a vinyl aromatic compound monomer, a (meth)acrylic-based monomer, a monomer having a crosslinkable functional group as needed, and other monomers , the radical reaction can be carried out in the presence of a polymerization initiator. As a method for carrying out the radical reaction, a conventionally known method can be used, and examples thereof include solution polymerization (boiling point polymerization or isothermal polymerization), emulsion polymerization, suspension polymerization, and bulk polymerization.

In the adhesive tape containing the copolymer of the present invention, the content of bio-derived carbon is preferably 10% by weight or more. Bio-derived carbon content of 10% by weight or more is the standard for "bio-based products". By setting the content of bio-derived carbon in the adhesive tape containing the copolymer of the present invention to 10% by weight or more, it is possible to reduce the environmental impact from the viewpoint of saving oil resources or reducing the amount of carbon dioxide emissions. Lower adhesive tape. A more preferable lower limit of the content of the above-mentioned biomass-derived carbon is 20% by weight or more, a further preferable lower limit is 40% by weight, a further more preferable lower limit is 50% by weight, and a further preferable lower limit is 60% by weight. The upper limit of the content rate of the above-mentioned biomass-derived carbon is not particularly limited, and may be 100% by weight. Among them, the content of the bio-derived carbon in the foam base material is more preferably 50% by weight or more, and the content of the bio-derived carbon in the above copolymer is still more preferably 50% by weight or more.

In the adhesive tape containing the copolymer of the present invention, regarding the material of the above-mentioned foam base material other than the above-mentioned copolymer, its content, apparent density, gel fraction, average cell diameter, thickness, and production method, the following can be used. The above-mentioned foam base material of the adhesive tape using the block copolymer is the same.

In the adhesive tape containing the copolymer of the present invention, the same adhesive layer as the adhesive layer of the adhesive tape using the block copolymer can be used for the above-mentioned adhesive layer.

In the adhesive tape containing the copolymer of the present invention, the parts other than the above-mentioned foam base material and the adhesive layer can be used the same as those of the above-mentioned adhesive tape using the block copolymer. [Effect of invention]

According to the present invention, it is possible to provide an adhesive tape which has excellent flexibility and impact resistance and also has a low environmental load.

Hereinafter, the aspect of the present invention will be described in further detail by way of examples, but the present invention is not limited to these examples.

(Example 1) (1) Manufacture of unfoamed substrate 0.902 g of 1,6-hexanedithiol, 1.83 g of carbon disulfide, and 11 mL of dimethylformamide were put into a two-necked flask, and stirred at 25°C. 2.49 g of triethylamine was added dropwise thereto over 15 minutes, and the mixture was stirred at 25°C for 3 hours. Then, 2.75 g of α-bromophenylacetic acid (methyl-α-bromophenylacetic acid) was added dropwise over 15 minutes, and the mixture was stirred at 25° C. for 4 hours. Then, 100 mL of extraction solvent (n-hexane:ethyl acetate=50:50) and 50 mL of water were added to the reaction liquid, and liquid separation extraction was performed. The organic layers obtained by the first and second liquid separation extractions were mixed, and washed successively with 50 mL of 1 M hydrochloric acid, 50 mL of water, and 50 mL of saturated brine. After adding sodium sulfate to the washed organic layer and drying, the sodium sulfate was filtered, the filtrate was concentrated by an evaporator, and the organic solvent was removed. The obtained concentrate was purified by silica gel column chromatography, thereby obtaining the RAFT agent.

87 parts by weight of styrene (St), 12 parts by weight of acrylic acid (AAc), 1 part by weight of hydroxyethyl acrylate (HEA), 1.9 parts by weight of RAFT agent and 0.2 parts by weight of 2,2'-azo Bis(2-methylbutyronitrile) (ABN-E) was put into a two-necked flask, the inside of the flask was replaced with nitrogen, and the temperature was raised to 85°C. Then, it stirred at 85 degreeC for 6 hours to carry out a polymerization reaction (first-stage reaction). After the completion of the reaction, 4000 parts by weight of n-hexane was put into the flask, and after stirring to precipitate the reactant, unreacted monomers (St, AA, HEA) and RAFT agent were filtered, and the reactant was depressurized at 70°C. The copolymer (hard block) is obtained by drying.

Will contain 50 parts by weight of butyl acrylate (BA, non-bio-derived), 50 parts by weight of n-heptyl acrylate (nHPA, derived from biology), 0.058 parts by weight of ABN-E and 50 parts by weight of ethyl acetate The mixture and the copolymer (hard block) obtained above were put into a two-necked flask, the inside of the flask was replaced with nitrogen, and the temperature was raised to 85°C. After that, the polymerization reaction (second-stage reaction) was carried out by stirring at 85° C. for 6 hours, and a product containing “a hard block and a block (soft block) derived from a (meth)acrylic monomer) was obtained. block copolymer" reaction solution. In addition, the blending amount of the mixture (block and hard block derived from the (meth)acrylic monomer) was set so that the content of the hard block in the obtained block copolymer was 17% by weight. quantity. Take a part of the reaction solution, put 4000 parts by weight of n-hexane into it, stir to precipitate the reactant, filter the unreacted monomers (BA, nHPA) and the solvent, and dry the reactant under reduced pressure at 70°C. The block copolymer was taken out from the reaction liquid. The weight average molecular weight of the obtained block copolymer was measured by the GPC method and found to be 250,000. Regarding the above weight average molecular weight, "2690 Separations Module" manufactured by Waters Corporation was used as a measuring device, "GPC KF-806L" manufactured by Showa Denko Corporation was used as a column, ethyl acetate was used as a solvent, and the sample flow rate was 1 mL/ min and column temperature of 40°C were measured.

The obtained block copolymer was dissolved in ethyl acetate so that the solid content ratio was 35%, and 0.30 parts by weight of Expancel 461-40 ( Japan Fillite Co., Ltd. product, denoted as DU40 in the table), and 0.2 parts by weight of Tetrad C (manufactured by Mitsubishi Gas Chemical Co., Ltd.) as a crosslinking agent, and further stirred sufficiently to obtain a base material solution. The obtained substrate solution was coated on the release-treated side of a 50 μm polyethylene terephthalate (PET) film that had undergone release treatment on one side, and was dried at 90° C. for 7 minutes, thereby obtaining an unfinished film. Foam base. The thickness of the unfoamed base material was adjusted so that it might become 100 μm when the unfoamed base material was heated at 130° C. for 1 minute.

(2) Preparation of adhesive solution After adding 52 weight part of ethyl acetate to the reactor equipped with a thermometer, a stirrer, and a condenser, and nitrogen-substituting, the reactor was heated and reflux was started. 0.08 parts by weight of azobisisobutyronitrile as a polymerization initiator was added after 30 minutes from the time when the ethyl acetate was boiled. 70 parts by weight of butyl acrylate, 27 parts by weight of 2-ethylhexyl acrylate, 3 parts by weight of acrylic acid, and 0.2 parts by weight of 2-hydroxyethyl acrylate were added dropwise uniformly and slowly over 1 hour and 30 minutes. The formed monomer mixture is allowed to react. 0.1 part by weight of azobisisobutyronitrile was added 30 minutes after the completion of the dropwise addition, and a polymerization reaction was carried out for 5 hours, and ethyl acetate was added to the reactor for dilution while cooling to obtain acrylic acid with a solid content of 40% by weight. Solutions of random copolymers. The weight-average molecular weight of the obtained acrylic random copolymer was measured by the GPC method and found to be 710,000. The ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) was 5.5. The weight-average molecular weight and number-average molecular weight described above were measured using "2690 Separations Module" manufactured by Waters Co., Ltd., "GPC KF-806L" manufactured by Showa Denko Co., Ltd. as a column, and ethyl acetate was used as a solvent. The measurement was performed under the conditions of a flow rate of 1 mL/min and a column temperature of 40°C. To 100 parts by weight of the solid content of the obtained acrylic random copolymer, 15 parts by weight of polymerized rosin ester with a softening point of 150°C, 10 parts by weight of terpene phenol with a softening point of 145°C, and 10 parts by weight of a softening point of 70°C were added. ℃ of rosin esters. Further, 30 parts by weight of ethyl acetate (manufactured by Fuji Chemical Co., Ltd.) and 3.0 parts by weight of an isocyanate-based crosslinking agent (Coronate L45, manufactured by Tosoh Corporation) were added and stirred to obtain an adhesive solution.

(3) Manufacture of adhesive tape Using a doctor blade, the obtained adhesive solution was applied to the release-treated surface of a 50-μm polyethylene terephthalate (PET) film with a single-side release treatment in such a way that the thickness of the dry film was 50 μm. , the coating solution was dried by heating at 110° C. for 5 minutes to obtain an adhesive layer. Next, another adhesive layer was produced by the same operation, and two adhesive layers were obtained. After that, the release film was peeled off from the unfoamed base material obtained above, and the two obtained adhesive layers were respectively attached to both sides of the unfoamed base material, and left to stand at 40°C. 48 hours. After 48 hours, it was taken out from an environment of 40°C, and heated at 130°C for 1 minute, thereby foaming the base material to obtain an adhesive tape.

(4) Measurement of tape density The density of the obtained adhesive tape was measured using an electronic hydrometer (ED120T manufactured by Mirage Corporation).

(5) Determination of apparent density of foam base material The density of the obtained foam base material was measured according to JIS K 7222 using an electronic hydrometer (ED120T manufactured by Mirage Corporation).

(6) Determination of the gel fraction of the foam substrate Only 0.1 g of the foam base material was taken out from the obtained adhesive tape, immersed in 50 ml of ethyl acetate, and shaken for 24 hours at a temperature of 23 degrees and 120 rpm using a shaker. After shaking, a metal mesh (pore size #200 mesh) was used to separate the ethyl acetate from the foam substrate swelled by absorbing ethyl acetate. The separated foam substrate was dried at 110°C for 1 hour. The weight of the foam base material containing the metal mesh after drying was measured, and the gel fraction of the foam base material was calculated using the following formula. Gel fraction (wt%)=100×(W1-W2)/W0 (W0: initial weight of foam substrate; W1: weight of foam substrate including metal mesh after drying; W2: initial weight of metal mesh)

(7) Determination of bio-derived carbon content of adhesive tape and base material For the obtained adhesive tape and foam base material, the concentration of carbon radioisotope ( ¹⁴ C) was measured according to ASTM D6866, and the Bio-derived carbon content of adhesive tapes and substrates.

(Examples 2 to 15, Comparative Examples 1 to 3) An adhesive tape was obtained in the same manner as in Example 1, except that the composition, apparent density, thickness, and blending amount of the foaming agent were set as shown in Table 1. In Comparative Examples 1 and 3, since a foaming agent was not included, it was still an unfoamed body after heating at 130° C. for 1 minute. Each measurement was performed in the same manner as in Example 1 with respect to the obtained adhesive tape and foam substrate (Comparative Examples 1 and 3, which were non-foamed substrates). In Comparative Example 2, SIS (styrene-isoprene block copolymer, Quintac 3421 manufactured by Zeon Corporation) was used as the block copolymer constituting the base material of the foam. In addition, the raw materials in the table are as follows. nOA: n-octyl acrylate (bio-derived) 1-MHA: 1-methylheptyl acrylate (bio-derived) LA: Lauryl Acrylate (Bio-derived) LMA: Lauryl Methacrylate (Bio-derived) IBOA: Isobornyl Acrylate (Bio-derived) Isoprene: Non-(meth)acrylic monomers (non-biologically derived)

(Examples 16 and 17) (1) Manufacture of unfoamed substrate A non-foamed base material was obtained in the same manner as in Example 1, except that the composition was set as shown in Table 1.

(2) Preparation of adhesive solution Ethyl acetate as a polymerization solvent was added to the reaction vessel, and after bubbling with nitrogen gas, the reaction vessel was heated and refluxed while flowing in nitrogen gas. Then, the polymerization initiator solution obtained by diluting 0.1 parts by weight of azobisisobutyronitrile as a polymerization initiator by 10 times with ethyl acetate was put into the reaction vessel, and 96.9 parts by weight of acrylic acid was added dropwise over 2 hours. n-heptyl ester (bio-derived), 2.9 parts by weight of acrylic acid and 0.1 part by weight of 2-hydroxyethyl acrylate. After the dropwise addition was completed, 0.1 part by weight of azobisisobutyronitrile as a polymerization initiator was diluted 10 times with ethyl acetate and the polymerization initiator solution was put into the reaction vessel, and the polymerization reaction was carried out for 4 hours. Thus, a solution containing an acrylic random copolymer was obtained. The weight average molecular weight of the obtained acrylic random copolymer was measured by the GPC method, and the result was 1 million. The ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) was 5.5. The weight-average molecular weight and number-average molecular weight described above were measured using "2690 Separations Module" manufactured by Waters Co., Ltd., "GPC KF-806L" manufactured by Showa Denko Co., Ltd. as a column, and ethyl acetate was used as a solvent. The measurement was performed under the conditions of a flow rate of 1 mL/min and a column temperature of 40°C. To 100 parts by weight of the solid content of the obtained acrylic random copolymer, 15 parts by weight of polymerized rosin ester with a softening point of 150°C, 10 parts by weight of terpene phenol with a softening point of 145°C, and 10 parts by weight of a softening point of 100°C were added. ℃ of rosin esters. Further, 30 parts by weight of ethyl acetate (manufactured by Fuji Chemical Co., Ltd.) and 0.2 parts by weight of an isocyanate-based crosslinking agent (Coronate L45, manufactured by Tosoh Corporation) were added and stirred to obtain an adhesive solution.

(3) Manufacture of adhesive tape An adhesive tape was obtained in the same manner as in Example 1, except that the obtained unfoamed substrate and adhesive solution were used. With respect to the obtained adhesive tape, each measurement was performed in the same manner as in Example 1.

(Example 18) (1) Manufacture of unfoamed substrate After adding 52 weight part of ethyl acetate to the reactor equipped with a thermometer, a stirrer, and a condenser, and nitrogen-substituting, the reactor was heated and reflux was started. 0.08 parts by weight of azobisisobutyronitrile as a polymerization initiator was added after 30 minutes from the time when the ethyl acetate was boiled. 90 parts by weight of n-heptyl acrylate, 9 parts by weight of styrene (St, non-biologically derived), 1 part by weight of acrylic acid (AAc, non-biologically derived) were uniformly and slowly added dropwise thereto over a period of 1 hour and 30 minutes. ) to form the monomer mixture and make it react. 30 minutes after the completion of the dropwise addition, 0.1 part by weight of azobisisobutyronitrile was added, and a polymerization reaction was carried out for 5 hours, and ethyl acetate was added to the reactor for dilution and cooling, whereby a solid content of 40% by weight was obtained. solution of regular copolymer. The weight-average molecular weight of the obtained random copolymer was measured by the GPC method and found to be 350,000. Regarding the above weight average molecular weight, "2690 Separations Module" manufactured by Waters Corporation was used as a measuring device, "GPC KF-806L" manufactured by Showa Denko Corporation was used as a column, ethyl acetate was used as a solvent, and the sample flow rate was 1 mL/ min and column temperature of 40°C were measured.

The obtained random copolymer was dissolved in ethyl acetate so that the solid content ratio was 35%, and 0.3 parts by weight of Expancel 461-40, a foaming agent, 100 parts by weight of the random copolymer was added. 0.2 parts by weight of Tetrad C as a crosslinking agent was further stirred sufficiently to obtain a substrate solution. The obtained substrate solution was coated on the release-treated side of a 50 μm polyethylene terephthalate (PET) film that had undergone release treatment on one side, and was dried at 90° C. for 7 minutes, thereby obtaining an adhesive bond. An unfoamed substrate composed of branched copolymers. The thickness of the unfoamed base material was adjusted so that it might become 100 μm when the unfoamed base material was heated at 130° C. for 1 minute.

(2) Manufacture of adhesive tape An adhesive tape was obtained in the same manner as in Example 1, except that the obtained unfoamed base material composed of the random copolymer was used. With respect to the obtained adhesive tape, each measurement was performed in the same manner as in Example 1.

(Examples 19 to 21, Comparative Example 4) An adhesive tape was obtained in the same manner as in Example 18, except that the composition of the foam base material was set as shown in Table 2. With respect to the obtained adhesive tape, each measurement was performed in the same manner as in Example 1.

＜Evaluation＞ The following evaluations were performed on the adhesive tapes obtained in Examples and Comparative Examples. The results are shown in Tables 1 and 2.

(Evaluation of impact resistance) The obtained adhesive tape was punched into a zigzag shape of 45 mm×60 mm in shape and 1 mm in width. One side of the punched adhesive tape was attached to the center of a 80 mm x 115 mm, 2 mm thick zigzag stainless steel plate with a hole of 40 mm x 40 mm in the center. Then, a tempered glass plate with a thickness of 50 mm × 70 mm and a thickness of 4 mm was attached to the other side of the adhesive tape, and pressed with a 5 kg hammer for 10 seconds. Laminated body. The obtained laminated body was fixed to a stainless steel frame-shaped body (inner diameter: 60 mm×90 mm) so that the tempered glass plate became the lower surface. After that, a 150 g iron ball was dropped toward the center of the tempered glass plate. Increase the drop height of the iron ball, and measure the height of the iron ball when the tempered glass plate is peeled off from the stainless steel plate. The case where the height of the iron ball is 50 cm or more when the tempered glass plate is peeled from the stainless steel plate is set as "◎", the case where it is more than 40 cm and less than 50 cm is set as "○", and the case where it is less than 40 cm is set as "○". As "X", the impact resistance was evaluated.

(evaluation of retention) A schematic diagram illustrating the holding force test of the adhesive tape is shown in FIG. 1 . First, one side (front side) of the test piece 1 with a size of 25 mm × 25 mm of the adhesive tape was attached to the SUS plate 2, and a 2 kg rubber roller was pressed at 300 mm/min from the other side (back side) side of the test piece 1. The speed goes back and forth once. Then, the aluminum plate 3 was attached to the back of the test piece 1, and the aluminum plate 3 was pressed with a weight of 0.5 kg for 10 seconds to make it isopressed. Then, a sample for holding force test was produced. For the holding force test sample, a weight 4 of 0.5 kg or 1.0 kg was attached to one end of the aluminum plate 3 at 100° C. in such a manner that a load was applied to the test piece 1 and the aluminum plate 3 in the horizontal direction, and the weight after 1 hour was measured. The offset length of the code. Moreover, the weight 4 of 1.0 kg was attached, and the offset length after 2 hours was also measured. For the obtained measurement results, the case where the offset length is 0 (no offset) is set as "◎", the case where the offset length is greater than 0 and less than 1 mm is set as "○", and the offset length is set as 1 mm or more or the case where the adhesive tape was peeled off and dropped was set as "x", and the holding force was evaluated.

(Evaluation of compressive strength) About the obtained double-sided adhesive tape, the 25% compressive strength was calculated based on JISK-6767. When the obtained value was 50 kPa or less, it was set as "◎", when it was more than 50 kPa and 80 kPa or less, it was set as "○", and when it was more than 80 kPa, it was set as "x", and the evaluation was performed.

[Table 1] Example Example Example Example Example Example Example Example Example Example Example Example Example Example Example Example Example Comparative example Comparative example Comparative example 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 1 2 3 foam base Copolymer Types of Copolymers - block block block block block block block block block block block block block block block block block block block block hard block content weight% 17 17 17 17 17 17 17 17 2 40 17 17 17 17 17 17 17 17 14 17 Composition (weight ratio) St - 87 87 87 87 87 87 87 87 87 87 87 87 87 87 100 87 87 87 100 87 AAc - 12 12 12 12 12 12 12 12 12 12 12 12 12 12 - 12 12 12 - 12 HEA - 1 1 1 1 1 1 1 1 1 1 1 1 1 1 - 1 1 1 - 1 soft block content weight% 83 83 83 83 83 83 83 83 98 60 83 83 83 83 83 83 83 83 86 83 Composition (weight ratio) BA - 50 - - - - - - - - - - - - - - - 100 100 - 50 nHPA - 50 100 50 50 50 50 80 - 100 100 100 100 100 100 98 100 - - - 50 nOA - - - 50 - - - - 100 - - - - - - - - - - - - 1-MHA - - - - 50 - - - - - - - - - - - - - - - - LA - - - - - 50 - - - - - - - - - - - - - - - LMA - - - - - - 50 - - - - - - - - - - - - - - IBOA - - - - - - - 20 - - - - - - - - - - - - - Isoprene - - - - - - - - - - - - - - - - - - - 100 - AAc - - - - - - - - - - - - - - - 2 - - - - - weight average molecular weight Ten thousand 25 25 25 25 25 25 25 twenty four 31 twenty two 25 25 25 25 twenty four 25 twenty three 25 25 25 foaming agent type - DU40 DU40 DU40 DU40 DU40 DU40 DU40 DU40 DU40 DU40 DU40 DU40 DU40 DU40 DU40 DU40 DU40 - DU40 - number of copies parts by weight 0.30 0.30 0.30 0.30 0.30 0.30 0.30 0.30 0.30 3.23 5.12 0.12 0.30 0.30 0.30 0.30 0.30 - 0.30 - cross-linking agent number of copies parts by weight 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 1 - 0.2 gel fraction % 41 40 40 40 39 42 41 41 41 40 35 52 40 40 40 40 44 41 0 41 apparent density g/cm ³ 0.88 0.88 0.88 0.88 0.88 0.88 0.88 0.88 0.88 0.5 0.35 0.95 0.88 0.88 0.88 0.88 0.88 1.04 0.88 1.04 thickness μm 100 100 100 100 100 100 100 100 100 100 100 100 40 900 100 100 100 100 100 100 adhesive layer Thickness (each side) μm 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 The content of bio-derived carbon in the adhesive zone % 27 40 40 40 42 41 40 41 45 29 33 40 33 52 39 56 13 13 13 27 Bio-derived carbon content of the substrate % 29 56 57 57 60 58 57 58 68 38 56 56 56 56 54 65 0 0 0 29 Evaluation impact resistance high cm 40 55 55 50 40 55 40 55 60 40 40 65 40 95 55 55 40 20 20 20 determination - ○ ◎ ◎ ◎ ○ ◎ ○ ◎ ◎ ○ ○ ◎ ○ ◎ ◎ ◎ ○ × × × Retentivity 0.5 kg, 1 hour - ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ○ ◎ 1 kg, 1 hour - ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ○ ◎ ◎ ◎ ◎ ◎ ○ ◎ ◎ ◎ × ◎ compressive strength measured value kPa 65 45 42 48 75 40 80 40 40 80 34 80 65 39 43 45 68 80 450 75 determination - ○ ◎ ◎ ◎ ○ ◎ ○ ◎ ◎ ○ ◎ ○ ○ ◎ ◎ ◎ ○ ○ × ○

[Table 2] Example Example Example Example Comparative example 18 19 20 twenty one 4 foam base Copolymer Types of Copolymers - random random random random random Composition (weight ratio) BA - - - - - 100 nHPA - 90 - 90 65 - nOA - - 90 - - - St - 9 9 9 5 - AAc - 1 1 0.1 30 3 weight average molecular weight Ten thousand 35 34 35 32 30 foaming agent type - DU40 DU40 DU40 DU40 DU40 number of copies parts by weight 0.30 0.30 0.30 0.30 0.30 cross-linking agent number of copies parts by weight 0.2 0.2 1 0.01 0.2 gel fraction % 41 41 38 36 40 apparent density g/cm ³ 0.88 0.88 0.88 0.88 0.88 thickness μm 100 100 100 100 100 adhesive layer Thickness (each side) μm 50 50 50 50 50 The content of bio-derived carbon in the adhesive zone % 42 43 43 36 13 Bio-derived carbon content of the substrate % 61 64 64 49 0 Evaluation impact resistance high cm 45 45 45 40 25 determination - ○ ○ ○ ○ × Retentivity 0.5 kg, 1 hour - ◎ ◎ ◎ ◎ ◎ 1 kg, 1 hour - ○ ○ ○ ○ ○ compressive strength measured value kPa 48 46 45 79 75 determination - ◎ ◎ ◎ ○ ○ [Industrial Availability]

According to the present invention, it is possible to provide an adhesive tape which has excellent flexibility and impact resistance and also has a low environmental load.

1: The size of the adhesive tape is 25 mm × 25 mm test piece 2: SUS board 3: Aluminum plate 4: Weight (0.5 kg or 1.0 kg)

[Fig. 1(a)] is a front view showing the state of the holding force test of the adhesive tape. [Fig. 1(b)] is a side view showing the state of the holding force test of the adhesive tape.

none.

Claims (16)

An adhesive tape having a foam base material and at least one adhesive layer, and The above-mentioned foam base material contains a block copolymer, and the above-mentioned block copolymer has a block derived from a (meth)acrylic monomer, The above-mentioned adhesive tape contains carbon derived from living organisms. The adhesive tape of claim 1, wherein the block copolymer has at least one hard block. The adhesive tape according to claim 2, wherein the block copolymer contains 1 wt % or more and 40 wt % or less of the hard block. The adhesive tape according to claim 2 or 3, wherein the hard block has a structure derived from a vinyl aromatic compound monomer. The adhesive tape according to any one of claims 2 to 4, wherein the hard block has a structure derived from a monomer having a crosslinkable functional group. An adhesive tape having a foam base material and at least one adhesive layer, and The above-mentioned foam base material contains a copolymer, The above-mentioned copolymer has a structure derived from a vinyl aromatic compound monomer and a structure derived from a (meth)acrylic monomer, The above-mentioned adhesive tape contains carbon derived from living organisms. The adhesive tape according to claim 6, wherein the copolymer has a structure derived from a monomer having a crosslinkable functional group. The adhesive tape according to claim 6 or 7, wherein the content of the structure derived from the (meth)acrylic monomer in the copolymer is 70% by weight or more and 98% by weight or less. The adhesive tape according to any one of claims 1 to 8, wherein the foam base material contains bio-derived carbon. The adhesive tape according to any one of claims 1 to 9, wherein the (meth)acrylic monomer contains a (meth)acrylic monomer containing bio-derived carbon. The adhesive tape according to claim 10, wherein the (meth)acrylic monomer containing bio-derived carbon has an alkyl group having 7 to 12 carbons. The adhesive tape according to claim 10 or 11, wherein the (meth)acrylic monomer homopolymer containing bio-derived carbon has a glass transition temperature Tg of -40°C or lower (meth)acrylic monomer body. The adhesive tape according to any one of claims 10 to 12, wherein the (meth)acrylic mono-system containing bio-derived carbon is n-heptyl acrylate or n-octyl acrylate. The adhesive tape according to any one of claims 1 to 13, wherein the content of bio-derived carbon is 50% by weight or more. The adhesive tape according to any one of claims 1 to 14, wherein the content of bio-derived carbon in the foam base material is 50% by weight or more. The adhesive tape according to any one of claims 1 to 15, wherein the content of the bio-derived carbon in the block copolymer or the copolymer is 50% by weight or more.

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