CN116262870A

CN116262870A - Adhesive tape

Info

Publication number: CN116262870A
Application number: CN202111534516.0A
Authority: CN
Inventors: 李旭; 德山英幸; 潘健; 段鹏真
Original assignee: Nitto Denko Shanghai Songjiang Co Ltd; Nitto Denko Corp
Current assignee: Nitto Denko Shanghai Songjiang Co Ltd; Nitto Denko Corp
Priority date: 2021-12-15
Filing date: 2021-12-15
Publication date: 2023-06-16

Abstract

The invention provides an adhesive tape. The adhesive tape has high temperature resistance, low shrinkage rate at high temperature, no influence on resin after being adhered to the surface of engineering resin at high temperature, easy stripping, low cost and convenient use; solves the problems that the common adhesive tape in the market has large shrinkage rate at high temperature, changes the surface state of the resin after being adhered to the surface of engineering resin, is not easy to peel off, and is difficult to apply in the temperature range from 100 ℃ to 180 ℃.

Description

Adhesive tape

Technical Field

The present invention relates to an adhesive tape. And more particularly, to an adhesive tape which has high temperature resistance, low shrinkage at high temperature, and low cost, and which does not affect the surface of the resin after being adhered to the surface of an engineering resin at high temperature.

Background

It is known that an adhesive tape is widely used because it is applied to various adherend surfaces in various industrial fields to provide temporary fixing, heat-resistant protection, and the like. However, conventional adhesive tapes often shrink easily at high temperatures, and after use at high temperatures, the adhesive tapes are particularly likely to contaminate the surface of the engineering resin when peeled off after being adhered to the surface of the engineering resin, thereby changing the surface state of the engineering resin material.

Therefore, there is a need for an adhesive tape which can reduce the above drawbacks, has high temperature resistance, has low shrinkage at high temperature, is easy to use, and has low cost.

Disclosure of Invention

Problems to be solved by the invention

The purpose of the present invention is to provide an adhesive tape which has high temperature resistance, low shrinkage at high temperature, and is easy to peel without affecting the surface of an engineering resin after being adhered to the surface of the resin at high temperature.

Solution for solving the problem

The present inventors have made intensive studies to solve the above problems, and as a result, have found that the above problems can be solved by controlling the heat shrinkage rate, the elastic modulus at 120 ℃ and the elongation at break of an adhesive tape after leaving the adhesive tape at 150 ℃ for 30 minutes within specific ranges, and have completed the present invention.

Namely, the present invention is as follows.

[1] An adhesive tape comprising a substrate and an adhesive layer laminated on at least one side of the substrate, wherein the adhesive tape has a heat shrinkage rate of 2% or less after being left at 150 ℃ for 30 minutes, an elastic modulus of 0.2 to 0.6GPa at 120 ℃, and an elongation at break of 110 to 400%.

[2] The adhesive tape according to [1], wherein a ratio of an adhesive force at room temperature after the adhesive tape is adhered to a resin plate to an adhesive force at 150 ℃ for 2 minutes is 0.5 to 0.85, wherein the adhesive force at room temperature is 0.3 to 1.2N/20mm.

[3] The adhesive tape according to [1] or [2], wherein the adhesive tape has a glass transition temperature (Tg) of 140 to 160 ℃ as measured by Differential Scanning Calorimetry (DSC).

[4] The adhesive tape according to [1] or [2], wherein the base material layer contains at least one selected from the group consisting of polycarbonate and polymethyl methacrylate; the thickness of the substrate layer is 20-100 mu m.

[5] The adhesive tape according to [1] or [2], wherein the base layer has a tensile strength of 55 to 120MPa, a tensile modulus of 2000 to 3000MPa, and a heat shrinkage at 150 ℃ of 0.5 to 0.7%.

[6] The adhesive tape according to [1] or [2], wherein the adhesive layer is formed of an adhesive composition comprising an acrylic polymer or polyurethane as a base polymer; optionally, the adhesive composition further comprises a cross-linking agent; preferably, the content of the crosslinking agent is 0.2 to 10 parts by weight based on 100 parts by weight of the base polymer; the thickness of the adhesive layer is 3-50 μm.

[7] The adhesive tape according to [6], wherein the acrylic polymer comprises, based on 100 parts by weight of the entire monomer components of the acrylic polymer: 70 to 93 parts by weight, preferably 80 to 90 parts by weight of a tacky monomer, 5 to 30 parts by weight, preferably 8 to 25 parts by weight of a hard monomer and 1 to 3 parts by weight of a copolymerizable monomer;

Preferably, the viscous monomer is selected from at least one of alkyl (meth) acrylates having an alkyl group of 4 to 20 carbon atoms;

the hard monomer is at least one selected from acrylonitrile, methyl methacrylate, vinyl acetate and styrene;

the copolymerizable monomer is at least one selected from the group consisting of a hydroxyl group-containing monomer, a carboxyl group-containing monomer, a sulfonic acid group-containing monomer, a phosphoric acid group-containing monomer, an epoxy group-containing monomer, an isocyanate group-containing monomer, an amide group-containing monomer, a monomer having a nitrogen atom-containing ring, a monomer having a succinimide skeleton, maleimides, itaconimides, aminoalkyl (meth) acrylates, alkoxyalkyl (meth) acrylates, vinyl ethers, and olefins.

[8] The method of using an adhesive tape according to any one of [1] to [7], comprising the steps of:

(1) Bonding the adhesive tape to a resin plate;

(2) The resin sheet to which the adhesive tape is adhered is subjected to a temperature of 120 to 160 ℃ and a pressure of 0.05 to 0.5MPa for a period of 2 to 180 seconds.

[9] The method of using an adhesive tape according to [8], wherein the surface roughness of one side of the resin sheet to which the adhesive tape is to be bonded is 0.2 μm.ltoreq.rz.ltoreq.10 μm.

[10] The method of using an adhesive tape according to [8] or [9], wherein one side of the resin sheet to which the adhesive tape is to be bonded has an acrylic coating.

ADVANTAGEOUS EFFECTS OF INVENTION

The adhesive tape has high temperature resistance, low shrinkage rate at high temperature, no influence on resin after being adhered to the surface of engineering resin at high temperature, easy stripping, low cost and convenient use, and is particularly suitable for application in the field of high temperature.

Detailed Description

Hereinafter, preferred embodiments of the present invention will be described. Matters necessary for the practice of the present invention other than matters specifically mentioned in the present specification are understood by those skilled in the art based on the teachings and technical knowledge at the time of application as to the practice of the present invention described in the present specification. The present invention can be implemented based on the content disclosed in the present specification and technical common knowledge in the field.

< adhesive tape >

The adhesive tape of the present invention comprises a substrate and an adhesive layer laminated on at least one side of the substrate, wherein the adhesive tape has a heat shrinkage rate of 2% or less after being left at 150 ℃ for 30 minutes, an elastic modulus of 0.2 to 0.6GPa at 120 ℃, and an elongation at break of 110 to 400%.

In addition, the adhesive tape of the present invention may be provided with a release liner on the outer side of the adhesive layer for the purpose of protecting the adhesive surface for a period of time before use.

In the present invention, "high temperature" generally means a temperature range higher than the environment in which the adhesive tape is used, and is generally 100 to 180 ℃. "room temperature" generally refers to an indoor ambient temperature of 20 to 25 ℃, e.g., 20 ℃, 21 ℃, 22 ℃, 23 ℃, 24 ℃, 25 ℃.

The term "adhesive tape" as used herein may include what is called an adhesive sheet, an adhesive label, an adhesive film, or the like. The adhesive tape disclosed herein may be a single sheet, or may be one further processed into various shapes. In some preferred embodiments, the adhesive tape of the present invention may be provided in a long strip shape.

The adhesive tape of the present invention has the following features: the heat shrinkage rate after being left at 150 ℃ for 30 minutes is 2% or less, the elastic modulus at 120 ℃ is 0.2-0.6 GPa, and the elongation at break is 110-400%.

In the invention, the high temperature resistance of the adhesive tape can be improved by controlling the thermal shrinkage rate of the adhesive tape after being placed at 150 ℃ for 30 minutes, the elastic modulus at 120 ℃ and the elongation at break within the specific ranges, so that the adhesive tape has low shrinkage rate at high temperature, can be gently peeled off after being adhered to the surface of engineering resin at high temperature, does not influence the surface of the resin, and does not cause damage or cause residual glue pollution.

If the adhesive tape has a heat shrinkage of more than 2% after being left at 150℃for 30 minutes, or an elastic modulus of less than 0.2GPa or more than 0.6GPa at 120℃or an elongation at break of less than 110% or more than 400%, the adhesive tape is not easily resistant to high temperature, has a large shrinkage at high temperature, and is poor in peeling operability, and an adherend such as an engineering resin is easily broken at peeling, and is easily contaminated with a residual adhesive after peeling.

In some preferred embodiments, the adhesive tape of the present invention has a ratio of adhesion at room temperature to adhesion at 150 ℃ for 2 minutes after bonding to a resin plate of 0.5 to 0.85, wherein the adhesion at room temperature is 0.3 to 1.2N/20mm.

In the present invention, by setting the ratio of the adhesive force at room temperature and the adhesive force at 150 ℃ for 2 minutes after the adhesive tape is adhered to the resin sheet and the adhesive force at room temperature within the above ranges, the high temperature resistance of the adhesive tape can be further improved to have a low shrinkage at a high temperature, and the adhesive tape can be gently peeled off after being adhered to the surface of the engineering resin at a high temperature without affecting the surface of the resin, causing damage or generating residual glue contamination.

If the ratio of the adhesive force at room temperature after the adhesive tape is adhered to the resin sheet to the adhesive force at 150 ℃ for 2 minutes is lower than 0.5 or higher than 0.85, or the adhesive force at room temperature is lower than 0.3N/20mm or higher than 1.2N/20mm, the adhesive tape is not easily resistant to high temperature, the shrinkage at high temperature is large, and the peeling operability is poor, the adherend such as engineering resin is easily broken at the time of peeling, and the residual glue contamination is easily generated after peeling.

In the present invention, the resin sheet is not particularly limited, and those types of commonly used engineering resin sheets, such as PC (polycarbonate) resin sheets, PMMA (polymethyl methacrylate) resin sheets, PMMA/PC resin sheets, PET (polyethylene terephthalate) resin sheets, PS (polystyrene) resin sheets, and the like, may be used.

In the present invention, after the adhesive tape is adhered to the resin sheet, the resin sheet to which the adhesive tape is adhered is preferably subjected to a temperature of 120 to 160 ℃ and a pressure of 0.05 to 0.5MPa for a time of 2 to 180s. After a period of time under the temperature and the pressure, the adhesive tape can be firmly adhered to the resin plate, so that the purpose of fixing the adhered object is achieved.

In some preferred embodiments, the surface roughness of the side of the resin sheet to which the adhesive tape is to be bonded is 0.2 μm or less Rz 10 μm or less, preferably 0.5 μm or less Rz 8 μm or less. By setting Rz to the above range, the influence of the adhesive tape on the surface flatness of the resin plate can be suppressed.

In some preferred embodiments, one side of the resin sheet to which the adhesive tape is to be bonded has an acrylic coating. By applying an acrylic coating on one side of the adhesive tape to be bonded, the resin plate and the bonding surface can be well protected, the resin plate is subjected to ultraviolet resistance, antistatic, antibacterial, mildew-proof, corrosion-proof, optical beautification and the like, and the adhesive tape is convenient to bond and easy to peel.

In some preferred embodiments, the adhesive tape has a glass transition temperature (Tg) of 140 to 160 ℃ as measured by Differential Scanning Calorimetry (DSC), preferably the glass transition temperature (Tg) is 143 to 153 ℃. By setting the glass transition temperature (Tg) in the above range, the cohesive force of the adhesive tape can be improved, the thermal stability, dimensional stability, and adhesiveness of the adhesive tape can be improved, and the object of firmly adhering the adherend can be achieved.

[ substrate layer ]

The material of the base material layer constituting the adhesive tape disclosed herein is not particularly limited, and may be appropriately selected according to the purpose of use, the manner of use, and the like of the adhesive tape.

As the substrate layer of the adhesive tape disclosed herein, various film substrates can be preferably used. The film substrate may be a porous substrate such as a foam film or a nonwoven fabric sheet, a non-porous substrate, or a substrate having a structure in which a porous layer and a non-porous layer are laminated. In some embodiments, as the film base material, a base material including a resin film (independent or independent) capable of independently maintaining a shape can be preferably used. The term "resin film" as used herein refers to a resin film having a non-porous structure, typically containing substantially no bubbles (no voids). The resin film may have a single-layer structure or a multilayer structure (for example, a three-layer structure) of two or more layers.

As the resin material constituting the resin film, for example, a resin such as a fluororesin such as polyester, polyolefin (PO), nylon 6, nylon 66, partially aromatic polyamide or the like (PA), polyimide (PI), polyamideimide (PAI), polyether ether ketone (PEEK), polyether sulfone (PES), polyphenylene sulfide (PPS), polycarbonate (PC), polymethyl methacrylate (PMMA), thermoplastic Polyurethane (TPU), ethylene-vinyl acetate copolymer (EVA), polytetrafluoroethylene (PTFE) or the like, an acrylic resin, polyacrylate, polystyrene, polyvinyl chloride (PVC), polyvinylidene chloride, cast polypropylene (CPP), or the like can be used. The resin film may be formed using a resin material containing 1 kind of such resin alone, or may be formed using a resin material obtained by blending 2 or more kinds of such resins. The resin film may be a non-stretched film or a stretched (for example, uniaxially stretched or biaxially stretched) film. Among these, from the viewpoint of better achieving the effects of the present invention, the base material layer preferably contains at least one selected from the group consisting of Polycarbonate (PC) and polymethyl methacrylate (PMMA).

To the resin film, known additives such as a light stabilizer, an antioxidant, an antistatic agent, a colorant (dye, pigment, etc.), a filler, a sliding agent, an antiblocking agent, etc. may be blended as necessary within a range that does not significantly impair the effects of the present invention. The blending amount of the additive is not particularly limited and may be appropriately set according to the use of the adhesive tape or the like.

The method for producing the resin film is not particularly limited. For example, conventionally known general resin film forming methods such as extrusion molding, inflation molding, T-die casting, and calender roll molding can be suitably used.

The substrate layer of the present invention may be a substrate consisting essentially of such a base film. Alternatively, the substrate layer of the present invention may be a substrate including an auxiliary layer in addition to the base film. Examples of the auxiliary layer include an optical property adjusting layer (e.g., a coloring layer or an antireflection layer), a printed layer for imparting a desired appearance to a substrate, a laminate layer, an antistatic layer, an undercoat layer, and a surface treatment layer such as a release layer.

The surface of the base material layer of the present invention may be subjected to any surface treatment in order to improve adhesion to an adjacent layer, retention, and the like. Examples of the surface treatment include chemical or physical treatments such as chromic acid treatment, ozone exposure, flame exposure, high-voltage electric shock exposure, and ionizing radiation treatment, and coating treatment.

The thickness of the base material layer of the present invention may be set to any appropriate thickness depending on the desired strength, flexibility, purpose of use, and the like. The thickness of the base material layer is preferably 20 to 100. Mu.m, more preferably 25 to 50. Mu.m.

In some preferred embodiments, the substrate layer has a tensile strength of 55 to 120MPa, a tensile modulus of 2000 to 3000MPa, and a heat shrinkage of 0.5 to 0.7% at 150 ℃. By making the base material layer satisfy these characteristics, the base material layer can be made to have excellent rigidity and hardness, and excellent heat shrinkage properties, which is advantageous for achieving the object of the present invention.

[ adhesive layer ]

As the adhesive constituting the adhesive layer, any suitable adhesive may be used as long as the effects of the present invention can be obtained. The binder may contain, for example, an acrylic polymer, a rubber polymer, a polyester polymer, a urethane polymer, a polyether polymer, a silicone polymer, a polyamide polymer, a fluorine polymer, or the like as a base polymer (i.e., a component accounting for 50% by weight or more of the polymer component). The adhesive layer in the technology disclosed herein may be a layer formed from an adhesive composition comprising such a base polymer. The form of the adhesive composition is not particularly limited, and may be, for example, various forms such as a water-dispersible form, a solvent form, a hot-melt form, an active energy ray-curable form (e.g., a photo-curable form), and the like.

The components of the adhesive composition of the present invention will be described in detail below.

(base Polymer)

The adhesive composition of the present invention comprises a base polymer. Preferably, the adhesive composition comprises an acrylic polymer or polyurethane as a base polymer.

The content of the base polymer is not particularly limited, but is preferably 60 mass% or more, more preferably 70 mass% or more, and even more preferably 80 mass% or more, based on the total amount of the adhesive composition (total weight, 100 mass%) from the viewpoint of obtaining sufficient adhesion reliability. By adjusting the content of the base polymer in the adhesive composition to be within the above range, an adhesive composition which is more excellent in structural stress relaxation property and durability and excellent in adhesion to an adherend can be provided.

The base polymer in the technology disclosed herein is preferably a polymer of the following monomer components: the monomer component contains a viscous monomer as a main monomer, other monomers (copolymerizable monomers) having copolymerizability with the main monomer, and a hard monomer. The main monomer herein means a main component among monomer components constituting the base polymer, that is, a component contained in the monomer component in an amount exceeding 50% by weight.

In a preferred embodiment, the adhesive monomer comprises an alkyl (meth) acrylate. In the present specification, the term alkyl (meth) acrylate refers to alkyl acrylate and/or alkyl methacrylate.

The alkyl (meth) acrylate is preferably an alkyl (meth) acrylate having an alkyl group with 4 to 20 carbon atoms. Specific examples of the alkyl (meth) acrylate in which the alkyl group has 4 to 20 carbon atoms include, but are not particularly limited to: n-butyl (meth) acrylate, isobutyl (meth) acrylate, sec-butyl (meth) acrylate, tert-butyl (meth) acrylate, pentyl (meth) acrylate, isopentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, nonyl (meth) acrylate, isononyl (meth) acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate, undecyl (meth) acrylate, dodecyl (meth) acrylate, tridecyl (meth) acrylate, tetradecyl (meth) acrylate, pentadecyl (meth) acrylate, hexadecyl (meth) acrylate, heptadecyl (meth) acrylate, octadecyl (meth) acrylate, nonadecyl (meth) acrylate and eicosyl (meth) acrylate. Of these, n-Butyl Acrylate (BA) and 2-ethylhexyl acrylate (2 EHA) are preferred. The alkyl (meth) acrylate may be used alone or in combination of two or more.

The content of the tacky monomer is preferably 70 to 93 parts by weight, more preferably 80 to 90 parts by weight, based on 100 parts by weight of the entire monomer components of the acrylic polymer. When the content of the tacky monomer is within the above range, excellent adhesion can be obtained.

As the hard monomer, a hard monomer that can form a hard polymer having a relatively high glass transition point can be suitably used. The hard monomer is useful for improving cohesive strength of the adhesive layer. The hard monomer may be used alone or in combination of 2 or more.

As non-limiting specific examples of the hard monomer, there may be mentioned, for example: acrylonitrile (AN), methyl Methacrylate (MMA), vinyl acetate (VAc), styrene, and the like.

The content of the hard monomer is preferably 5 to 30 parts by weight, more preferably 8 to 25 parts by weight, still more preferably 10 to 23 parts by weight, based on 100 parts by weight of the total monomer components of the acrylic polymer. When the content of the hard monomer is within the above range, cohesive strength and heat resistance can be further improved.

As the copolymerizable monomer, a monomer having a polar group can be suitably used. The monomer having a polar group is useful for introducing a crosslinking point into an acrylic polymer or improving the cohesive force of an acrylic polymer. The copolymerizable monomer may be used singly or in combination of 2 or more.

Non-limiting examples of the copolymerizable monomer include, for example, hydroxyl group-containing monomers (hydroxyl group-containing monomers), carboxyl group-containing monomers (hydroxyl group-containing monomers), sulfonic acid group-containing monomers, phosphoric acid group-containing monomers, epoxy group-containing monomers, isocyanate group-containing monomers, amide group-containing monomers, monomers having a ring having a nitrogen atom, monomers having a succinimide skeleton, maleimides, itaconimides, aminoalkyl (meth) acrylates, alkoxyalkyl (meth) acrylates, vinyl esters, olefins, and the like. Of these, at least 1 selected from hydroxyl group-containing monomers and carboxyl group-containing monomers is preferable.

The content of the copolymerizable monomer is preferably 1 to 3 parts by weight, more preferably 1.2 to 2.7 parts by weight, based on 100 parts by weight of the total monomer components of the acrylic polymer. When the content of the copolymerizable monomer is within the above range, the cohesive force of the adhesive can be prevented from becoming too high, and the adhesion can be improved.

The hydroxyl group-containing monomer means a monomer having at least one hydroxyl group in the molecule. In the case where the monomer component used to constitute the base polymer contains a hydroxyl group-containing monomer, that is, the base polymer contains a monomer unit derived from a hydroxyl group-containing monomer, since a secondary bond such as a hydrogen bond with an adherend is formed, the cohesive force of the base polymer (preferably an acrylic polymer) is improved, the change in adhesive force with time can be more effectively suppressed, and the adhesive residue to the adherend after peeling is less, and the adhesive composition has a higher aggregation property. In addition, when a crosslinking agent is used, a crosslinking reaction with the crosslinking agent can be effectively performed by adding a hydroxyl group-containing monomer to a raw material monomer of the base polymer, and the effect as a binder can be sufficiently exhibited. In addition, breakage of the adherend at the time of peeling operation can also be effectively prevented. The base polymer of the present embodiment may use 1 kind of hydroxyl group-containing monomer, or may use 2 or more kinds of hydroxyl group-containing monomers.

As specific examples of the hydroxyl group-containing monomer. Examples include: and hydroxyalkyl (meth) acrylates such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 8-hydroxyoctyl (meth) acrylate, 10-hydroxydecyl (meth) acrylate, 12-hydroxylauryl (meth) acrylate, and (4-hydroxymethylcyclohexyl) methyl (meth) acrylate.

The content of the hydroxyl group-containing monomer is not particularly limited, and is, for example, 1 to 3 parts by weight, preferably 1.2 to 2.7 parts by weight, based on 100 parts by weight of the total monomer components of the acrylic polymer. When the content of the hydroxyl group-containing monomer is within the above range, since secondary bonds such as hydrogen bonds with an adherend are formed, the cohesive force of the base polymer (preferably, the acrylic polymer) is improved, the change in adhesive force with time can be more effectively suppressed, and the residual adhesive to the adherend after peeling is less, and the adhesive film has higher aggregation. When the content of the hydroxyl group-containing monomer is less than 1 part by weight, sufficient adhesion is not obtained. When the content of the hydroxyl group-containing monomer is more than 3 parts by weight, the adhesive force becomes excessive, and there is a fear that blocking is easily generated. In addition, there is a concern that breakage of the adherend is likely to occur at the time of the peeling operation.

Carboxyl group-containing monomer means a monomer having at least one carboxyl group in the molecule. By including the carboxyl group-containing monomer in the raw material monomer of the base polymer, the cohesive force of the base polymer (preferably, the acrylic polymer) is improved due to the formation of a secondary bond such as a hydrogen bond with the adherend, whereby the change in adhesive force with time can be more effectively suppressed, and the adhesive residue after peeling is less to the adherend, and the adhesive composition has higher aggregation. In addition, by containing the carboxyl group-containing monomer in the raw material monomer of the base polymer, when the crosslinking agent is used, a crosslinking reaction with the crosslinking agent can be effectively performed, the effect as the adhesive can be sufficiently exhibited, and the breakage of the adherend at the time of the peeling operation can be effectively prevented.

Specific examples of the carboxyl group-containing monomer include: acrylic acid, methacrylic acid, carboxyethyl (meth) acrylate, carboxypentyl (meth) acrylate, crotonic acid, isocrotonic acid, fumaric acid, itaconic acid, maleic acid, citraconic acid, maleic anhydride, itaconic anhydride, and the like. Among these, acrylic acid and methacrylic acid are preferable. The above carboxyl group-containing monomers may be used singly or in combination of any of 1 or more of 2.

The content of the carboxyl group-containing monomer is not particularly limited, and is preferably 1 to 3 parts by weight, more preferably 1.2 to 2.7 parts by weight, based on 100 parts by weight of the total monomer components of the acrylic polymer, for example. When the content of the carboxyl group-containing monomer is within the above range, since secondary bonds such as hydrogen bonds with an adherend are formed, the cohesive force of the base polymer (preferably, the acrylic polymer) is improved, the change in adhesive force with time can be more effectively suppressed, and the residual adhesive to the adherend after peeling is less, and the adhesive film has higher aggregation. When the content of the carboxyl group-containing monomer is more than 3 parts by weight, the adhesive force becomes excessive, and there is a fear that blocking is easily generated. In addition, there is a concern that breakage of the adherend is likely to occur at the time of the peeling operation. When the content of the carboxyl group-containing monomer is less than 1 part by weight, sufficient adhesion is not obtained.

Examples of the sulfonic acid group-containing monomer include: styrene sulfonic acid, allyl sulfonic acid, sodium vinyl sulfonate, 2- (meth) acrylamide-2-methylpropanesulfonic acid, (meth) acrylamide propane sulfonic acid, sulfopropyl (meth) acrylate, acryloxynaphthalene sulfonic acid, and the like.

Examples of the phosphate group-containing monomer include: 2-hydroxyethyl acryloyl phosphate, and the like.

Examples of the epoxy group-containing monomer include: glycidyl (meth) acrylate, epoxy group-containing acrylates such as 2-ethyl glycidyl (meth) acrylate, allyl glycidyl ether, glycidyl (meth) acrylate, and the like.

Examples of the isocyanate group-containing monomer include: 2-isocyanatoethyl (meth) acrylate, and the like.

Examples of the amide group-containing monomer include: (meth) acrylamide; n, N-dialkyl (meth) acrylamides such as N, N-dimethyl (meth) acrylamide, N-diethyl (meth) acrylamide, N-dipropyl (meth) acrylamide, N-diisopropyl (meth) acrylamide, N-di (N-butyl) (meth) acrylamide, N-di (t-butyl) (meth) acrylamide, and the like; n-alkyl (meth) acrylamides such as N-ethyl (meth) acrylamide, N-isopropyl (meth) acrylamide, N-butyl (meth) acrylamide, and N-N-butyl (meth) acrylamide; n-vinylcarboxylic acid amides such as N-vinylacetamide; n, N-dimethylaminopropyl (meth) acrylamide, hydroxyethyl acrylamide, N-hydroxymethyl (meth) acrylamide, N-hydroxyethyl (meth) acrylamide, N-methylolpropane (meth) acrylamide, N-methoxymethyl (meth) acrylamide, N-methoxyethyl (meth) acrylamide, N-butoxymethyl (meth) acrylamide, N- (meth) acryloylmorpholine, and the like.

Examples of the monomer having a ring containing a nitrogen atom include: n-vinyl-2-pyrrolidone, N-methyl vinyl pyrrolidone, N-vinyl pyridine, N-vinyl piperidone, N-vinyl pyrimidine, N-vinyl piperazine, N-vinyl pyrazine, N-vinyl pyrrole, N-vinyl imidazole, N-vinyl oxazole, N- (meth) acryl-2-pyrrolidone, N- (meth) acryl piperidine, N- (meth) acryl pyrrolidine, N-vinyl morpholine, N-vinyl-3-morpholinone, N-vinyl-2-caprolactam, N-vinyl-1, 3-oxazin-2-one, N-vinyl-3, 5-morpholinedione, N-vinyl pyrazole, N-vinyl isoxazole, N-vinyl thiazole, N-vinyl isothiazole, N-vinyl pyridazine, and the like.

Examples of the monomer having a succinimide skeleton include: n- (meth) acryloyloxymethylene succinimide, N- (meth) acryl-6-oxahexamethylenesuccinimide, N- (meth) acryl-8-oxahexamethylenesuccinimide, and the like.

Examples of maleimide compounds include: n-cyclohexylmaleimide, N-isopropylmaleimide, N-laurylmaleimide, N-phenylmaleimide, and the like.

Examples of the itaconimides include: n-methyl itaconimide, N-ethyl itaconimide, N-butyl itaconimide, N-octyl itaconimide, N-2-ethylhexyl itaconimide, N-cyclohexyl itaconimide, N-month Gui Jiyi itaconimide and the like.

Examples of the aminoalkyl (meth) acrylate include: aminoethyl (meth) acrylate, N-dimethylaminoethyl (meth) acrylate, N-diethylaminoethyl (meth) acrylate, t-butylaminoethyl (meth) acrylate.

Examples of the alkoxyalkyl (meth) acrylate include: methoxyethyl (meth) acrylate, ethoxyethyl (meth) acrylate, propoxyethyl (meth) acrylate, butoxyethyl (meth) acrylate, ethoxypropyl (meth) acrylate, and the like.

Examples of vinyl ethers include: vinyl alkyl ethers such as methyl vinyl ether and ethyl vinyl ether.

Examples of the olefins include: ethylene, butadiene, isoprene, isobutylene, and the like.

The method for obtaining the acrylic polymer is not particularly limited, and various known polymerization methods such as a solution polymerization method, an emulsion polymerization method, a bulk polymerization method, a suspension polymerization method, and a photopolymerization method can be suitably used. For example, a solution polymerization method can be preferably employed. As a monomer supply method in the case of performing solution polymerization, a batch type in which all monomer raw materials are supplied at once, a continuous supply (drop wise) type, a split supply (drop wise) type, or the like can be suitably employed. The polymerization temperature in the solution polymerization may be appropriately selected depending on the types of monomers and solvents used, the types of polymerization initiators, and the like, and may be set to about 20 to 170℃for example (typically about 40 to 140 ℃).

The solvent (polymerization solvent) used in the solution polymerization may be appropriately selected from conventionally known organic solvents. For example, an aromatic compound (typically, aromatic hydrocarbon) selected from toluene and the like can be used; acetate esters such as ethyl acetate; aliphatic or alicyclic hydrocarbons such as hexane and cyclohexane; halogenated alkanes such as 1, 2-dichloroethane; lower alcohols such as isopropyl alcohol (for example, monohydric alcohols having 1 to 4 carbon atoms); ethers such as t-butyl methyl ether; any one or a mixture of two or more solvents selected from ketones such as methyl ethyl ketone.

The initiator used in the polymerization may be appropriately selected from conventionally known polymerization initiators depending on the kind of the polymerization method. For example, one or two or more azo polymerization initiators such as 2,2' -Azobisisobutyronitrile (AIBN) may be preferably used. As other examples of the polymerization initiator, there may be mentioned: persulfates such as potassium persulfate; peroxide initiators such as benzoyl peroxide and hydrogen peroxide; substituted ethane initiators such as phenyl substituted ethane; aromatic carbonyl compounds, and the like. As still other examples of the polymerization initiator, there are cited redox-type initiators obtained by combining a peroxide with a reducing agent. Such polymerization initiators may be used singly or in combination of two or more. The amount of the polymerization initiator to be used may be a usual amount, and for example, may be selected from the range of about 0.005 to about 1 part by weight (typically about 0.01 to about 1 part by weight) based on 100 parts by weight of the entire monomer components.

The weight average molecular weight (Mw) of the acrylic polymer in the technology disclosed herein is not particularly limited, and may be, for example, 1,000,000 or less, preferably 400,000 or more. In general, when the weight average molecular weight Mw exceeds 1,000,000, the cohesive force tends to increase due to the effect of entanglement of the polymer, and the fluidity tends to decrease, and a sufficient adhesive area may not be obtained, and the adherend may not be fixed.

On the other hand, the weight average molecular weight (Mw) of the soluble portion of the acrylic polymer is preferably 80,000 or less, more preferably 5,000 or more. When the weight average molecular weight Mw of the soluble portion of the acrylic polymer is greater than 80,000, the adhesive residue tends to occur after peeling after application heating due to insufficient cohesion of the polymer. When the weight average molecular weight Mw of the soluble portion of the acrylic polymer is less than 5,000, the adhesive is hard due to the higher gelation of the polymer, and the adherend is not coated, resulting in penetration of other substances.

The weight average molecular weight (Mw) herein refers to a value in terms of standard polystyrene obtained by Gel Permeation Chromatography (GPC). GPC apparatus may use, for example, model name "HLC-8320GPC" (column: TSKgelGMH-H (S)).

In the present invention, polyurethane may also be used as the base polymer. The polyurethane is not particularly limited, and is usually a polymer compound synthesized by polyaddition reaction of a polyol (e.g., diol) and a polyisocyanate (e.g., diisocyanate) at a prescribed ratio.

Examples of the polyhydric alcohol that can be used for the synthesis of the polyurethane include glycols such as ethylene glycol, propylene glycol, 1, 3-propanediol, 1, 4-butanediol, 1, 5-pentanediol, neopentyl glycol, 1, 6-hexanediol, 1, 8-octanediol, polyoxytetramethylene glycol, diethylene glycol, polyethylene glycol, and polypropylene glycol; polyester polyols as polycondensates of the above diols with dicarboxylic acids (e.g., adipic acid, azelaic acid, sebacic acid); carbonate diols such as polyalkylene carbonate diol, and the like. These may be used singly or in combination of two or more.

Examples of the polyisocyanate that can be used for the synthesis of the polyurethane include aromatic, aliphatic, and alicyclic diisocyanates, and polymers (e.g., dimers and trimers) of these diisocyanates. Examples of the diisocyanate include toluene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, isophorone diisocyanate, hydrogenated diphenylmethane diisocyanate, 1, 5-naphthalene diisocyanate, 1, 3-phenylene diisocyanate, 1, 4-phenylene diisocyanate, butane-1, 4-diisocyanate, 2, 4-trimethylhexamethylene diisocyanate, 2, 4-trimethylhexamethylene diisocyanate, cyclohexane-1, 4-diisocyanate, dicyclohexylmethane-4, 4-diisocyanate, 1, 3-bis (isocyanatomethyl) cyclohexane, methylcyclohexane diisocyanate, and m-tetramethylxylylene diisocyanate. These may be used singly or in combination of two or more. Among them, aromatic diisocyanates are preferred.

The polyurethane may contain other copolymerizable components in addition to the polyol and polyisocyanate. As the other copolymerization component, one or two or more of monocarboxylic acid, dicarboxylic acid, trifunctional or more polycarboxylic acid, hydroxycarboxylic acid, alkoxycarboxylic acid, derivative thereof, and the like can be used. The ratio of these other copolymerizable components is suitably set to less than about 30% by weight (for example, less than 10% by weight, typically less than 5% by weight) of the polyurethane.

The preparation of the polyurethanes may be carried out by methods known in the art, or the polyurethanes are also commercially available.

(crosslinking agent)

In the present invention, the adhesive composition preferably contains a crosslinking agent for the purpose of adjusting cohesion and the like. As the crosslinking agent, a conventionally used crosslinking agent can be used, and examples thereof include epoxy crosslinking agents, isocyanate crosslinking agents, melamine crosslinking agents, aziridine crosslinking agents, metal chelate crosslinking agents, and the like. These crosslinking agents may be used alone or in combination of two or more.

In a preferred embodiment, the crosslinking agent preferably comprises an epoxy-based crosslinking agent, an isocyanate-based crosslinking agent or a melamine-based crosslinking agent. By using these crosslinking agents, a proper crosslinking reaction can be generated, the cohesive force can be sufficiently improved, good adhesion can be ensured, and breakage of an adherend at the time of peeling operation can be effectively prevented.

As the epoxy-based crosslinking agent, a compound having two or more epoxy groups in one molecule can be used without particular limitation. Preferably an epoxy-based crosslinking agent having 3 to 5 epoxy groups in one molecule. The epoxy crosslinking agent may be used singly or in combination of two or more.

Specific examples of the epoxy-based crosslinking agent include, but are not particularly limited to: bisphenol A, epichlorohydrin-based epoxy resins, ethylene glycidyl ether, N, N, N ', N' -tetraglycidyl m-xylylenediamine, 1, 3-bis (N, N-diglycidyl aminomethyl) cyclohexane, 1, 6-hexanediol diglycidyl ether, polyethylene glycol diglycidyl ether, polyglycidyl ether, and the like. Examples of the commercial products of the epoxy-based crosslinking agent include trade names "tetra-C" and "tetra-X" manufactured by Mitsubishi gas chemical corporation, trade name "EPICLON CR-5L" manufactured by DIC corporation, trade name "DENACOL EX-512" manufactured by Daikovia chemical corporation, and trade name "TEPIC-G" manufactured by Nissan chemical industry corporation.

The amount of the epoxy-based crosslinking agent used is not particularly limited, and is, for example, preferably 0.05 to 1.1 parts by weight based on 100 parts by weight of the base polymer.

In the embodiment containing the epoxy-based crosslinking agent, the epoxy equivalent of the epoxy-based crosslinking agent is preferably 80 to 120g/eq.

As the isocyanate-based crosslinking agent, polyfunctional isocyanates (meaning compounds having an average of two or more isocyanate groups per molecule, including compounds having an isocyanurate structure) can be preferably used. The isocyanate-based crosslinking agent may be used singly or in combination of two or more.

Examples of the polyfunctional isocyanate include aliphatic polyisocyanates, alicyclic polyisocyanates, aromatic polyisocyanates, and the like.

Specific examples of the aliphatic polyisocyanate include: 1, 2-ethylene diisocyanate; 1, 2-butanediisocyanate, 1, 3-butanediisocyanate, 1, 4-butanediisocyanate and other butanediisocyanates; hexamethylene diisocyanate such as 1, 2-hexamethylene diisocyanate, 1, 3-hexamethylene diisocyanate, 1, 4-hexamethylene diisocyanate, 1, 5-hexamethylene diisocyanate, 1, 6-hexamethylene diisocyanate and 2, 5-hexamethylene diisocyanate; 2-methyl-1, 5-pentanediisocyanate, 3-methyl-1, 5-pentanediisocyanate, lysine diisocyanate, and the like.

Specific examples of the alicyclic polyisocyanate include: isophorone diisocyanate; cyclohexyl diisocyanate such as 1, 2-cyclohexyl diisocyanate, 1, 3-cyclohexyl diisocyanate, and 1, 4-cyclohexyl diisocyanate; cyclopentyl diisocyanate such as 1, 2-cyclopentyl diisocyanate and 1, 3-cyclopentyl diisocyanate; hydrogenated xylylene diisocyanate, hydrogenated toluene diisocyanate, hydrogenated diphenylmethane diisocyanate, hydrogenated tetramethylxylylene diisocyanate, 4' -dicyclohexylmethane diisocyanate, and the like.

Specific examples of the aromatic polyisocyanate include: 2, 4-toluene diisocyanate, 2, 6-toluene diisocyanate, 4' -diphenylmethane diisocyanate, 2' -diphenylmethane diisocyanate, 4' -diphenyl ether diisocyanate, 2-nitrobiphenyl-4, 4' -diisocyanate, 2' -diphenylpropane-4, 4' -diisocyanate 3,3' -dimethyldiphenylmethane-4, 4' -diisocyanate, 4' -diphenylpropane diisocyanate, isophthalate diisocyanate, p-phenylene diisocyanate, naphthalene-1, 4-diisocyanate, naphthalene-1, 5-diisocyanate, 3' -dimethoxybiphenyl-4, 4' -diisocyanate, xylylene-1, 4-diisocyanate, xylylene-1, 3-diisocyanate, and the like.

As the preferable polyfunctional isocyanate, polyfunctional isocyanates having an average of 3 or more isocyanate groups per molecule can be exemplified. The trifunctional or higher isocyanate may be a polymer (typically a dimer or trimer) of a difunctional or higher isocyanate, a derivative (e.g., an addition reaction product of a polyol and two or more polyfunctional isocyanates), a polymer, or the like. Examples may include: dimers or trimers of diphenylmethane diisocyanate, isocyanurate forms of hexamethylene diisocyanate (isocyanurate-structured trimer adducts), reaction products of trimethylol propane and toluene diisocyanate, reaction products of trimethylol propane and hexamethylene diisocyanate, polymethylene polyphenyl isocyanates, polyether polyisocyanates, polyester polyisocyanates, and other polyfunctional isocyanates. Examples of the commercial products of the polyfunctional isocyanate include "DURANATE TPA-100" manufactured by Asahi chemical Co., ltd., and "CORONATE L" manufactured by Japanese polyurethane Industrial Co., ltd., and "CORONATE HL" manufactured by Japanese polyurethane Industrial Co., ltd., and "CORONATE HK" manufactured by Japanese polyurethane Industrial Co., ltd., and "CORONATE HX" manufactured by Japanese polyurethane Industrial Co., ltd., and "CORONATE2096" manufactured by Japanese polyurethane Industrial Co., ltd.

In the embodiment containing the isocyanate-based crosslinking agent, the isocyanate group content (NCO content) in the isocyanate-based crosslinking agent is preferably 7 to 15%.

The amount of the isocyanate-based crosslinking agent used is not particularly limited, and is, for example, preferably 1 to 6 parts by weight based on 100 parts by weight of the base polymer.

Examples of melamine-based crosslinking agents include: hexamethylol melamine, butylated melamine resins (e.g., trade name "SUPER BECKAMINE J-820-60N" available from DIC Co., ltd.), and the like.

The amount of the melamine-based crosslinking agent used is not particularly limited, and is, for example, preferably 5 to 30 parts by weight based on 100 parts by weight of the base polymer.

Examples of the aziridine crosslinking agent include: trimethylolpropane tris [3- (1-aziridinyl) propionate ], trimethylolpropane tris [3- (1- (2-methyl) aziridinylpropionate) ]. As the aziridine crosslinking agent, commercially available ones can be used. For example, chemitite series (Nippon Shokubai Co., ltd.) such as Chemitite PZ-33 and Chemitite DZ-22E can be used.

Examples of the metal chelate crosslinking agent include: aluminum chelate compounds, titanium chelate compounds, zinc chelate compounds, zirconium chelate compounds, iron chelate compounds, cobalt chelate compounds, nickel chelate compounds, tin chelate compounds, manganese chelate compounds, chromium chelate compounds, and the like.

The amount of the crosslinking agent to be used is 0.2 to 10 parts by weight, preferably 0.5 to 5 parts by weight, based on 100 parts by weight of the base polymer.

In order to more effectively perform the above-mentioned crosslinking reaction, a crosslinking catalyst may also be used. As the crosslinking catalyst, for example, a tin catalyst (e.g., dioctyltin dilaurate) can be preferably used. The amount of the crosslinking catalyst used is not particularly limited, and is, for example, preferably 0.0001 to 1 part by weight based on 100 parts by weight of the base polymer.

In addition to the above components, the adhesive composition of the present invention may contain various additives, as necessary, which are usual in the adhesive field, such as leveling agents, crosslinking aids, plasticizers, softeners, antistatic agents, antioxidants, and the like, within a range that does not impair the effects of the present invention. Regarding such various additives, conventionally known additives can be used by a conventional method.

(formation of adhesive layer)

The adhesive layer disclosed herein may be formed by a known method. For example, a method (direct method) of forming an adhesive layer by directly applying (typically coating) the adhesive composition onto the substrate layer and drying it can be employed. In addition, a method (transfer method) of forming an adhesive layer on a surface (release surface) having releasability by applying the adhesive composition to the surface and drying the surface, and transferring the adhesive layer to a base material layer may also be employed. The transfer method is preferable from the viewpoint of productivity. The release surface may be a surface of a release liner, a back surface of a base material layer subjected to a release treatment, or the like. The pressure-sensitive adhesive layer disclosed herein is typically formed continuously, but is not limited to such a form, and may be formed in a regular or irregular pattern such as a dot shape or a stripe shape.

The adhesive composition may be applied by using a conventionally known coater such as a gravure roll coater, a die coater, or a bar coater. Alternatively, the adhesive composition may be applied by impregnation, curtain coating, or the like.

Drying of the adhesive composition is preferably performed under heating from the viewpoints of promoting the crosslinking reaction, improving the production efficiency, and the like. The drying temperature can be set, for example, at about 40 to 150℃and is usually preferably set at about 60 to 130 ℃. After drying the adhesive composition, aging may be further performed for the purpose of adjusting migration of components in the adhesive layer, progress of crosslinking reaction, relaxation of strain that may exist in the substrate film or the adhesive layer, and the like.

The thickness of the adhesive layer is not particularly limited, but is preferably 3 to 50. Mu.m, more preferably 5 to 30. Mu.m. By setting the thickness of the adhesive layer to the above range, good adhesion can be achieved. If the thickness of the pressure-sensitive adhesive layer is less than 3. Mu.m, the pressure-sensitive adhesive strength may be disadvantageously increased with time. On the other hand, if the thickness of the adhesive layer exceeds 50 μm, the effect of suppressing the adhesive force after bonding may be insufficient.

(backside treatment layer)

The adhesive tape of the present invention may further include a back surface treatment layer, which may be disposed on the opposite side of the substrate layer from the adhesive layer.

In some preferred embodiments, the backside treatment layer is formed by a backside treatment agent. The back surface treatment agent that can be used for forming the back surface treatment layer is not particularly limited, and any known or conventional one such as a silicone back surface treatment agent, a fluorine back surface treatment agent, a long-chain alkyl back surface treatment agent, and the like can be used depending on the purpose and use. The back surface treating agent may be used singly or in combination of two or more.

In some preferred embodiments, the back surface treatment preferably comprises a surfactant. As the surfactant, it is preferable to contain an alkane having 12 to 30 carbon atoms, such as sodium dodecyl sulfate, octadecyl vinyl sulfate, and the like.

The thickness of the back surface treatment layer is not particularly limited, but is preferably 0.05 to 1. Mu.m, more preferably 0.1 to 0.7. Mu.m. By setting the thickness of the back surface treatment layer to the above range, the effect of the present invention can be more effectively achieved.

(Release liner)

In the technology disclosed herein, a release liner may be used in the formation of an adhesive layer, the production of an adhesive tape, the preservation of an adhesive tape before use, circulation, shape processing, and the like. The release liner is not particularly limited, and for example, may be used: a release liner having a release treatment layer on the surface of a liner substrate such as a resin film or paper; and release liners made of a low-adhesion material such as a fluorine-based polymer (polytetrafluoroethylene or the like) or a polyolefin-based resin (polyethylene, polypropylene or the like). The release treatment layer may be formed by surface-treating the gasket base material with a release treatment agent such as silicone, long-chain alkyl, fluorine, or molybdenum sulfide.

(method for producing adhesive tape)

The adhesive tape of the present invention may be manufactured by any suitable method. For example, the following methods are mentioned: a method of applying the adhesive composition to the substrate layer, a method of transferring a coating layer formed by applying the adhesive composition to any appropriate substrate to the substrate layer, and the like.

As a coating method of the above adhesive composition, any suitable coating method may be employed. For example, each layer may be formed by drying after coating. Examples of the coating method include coating methods using a multiple coater, a die coater, a gravure coater, an applicator, a bar coater, air knife coating, reverse roll coating, lip coating, dip coating, offset printing, flexography, screen printing, and the like. Examples of the drying method include natural drying and heat drying. The heating temperature in the case of the heat drying can be set to any appropriate temperature according to the characteristics of the substance to be dried.

< use >

The adhesive tape disclosed herein can be applied to, for example, members constituting various portable devices (portable devices), and is preferably used for fixing, joining, forming, decorating, protecting, supporting, and the like of the members. The term "portable" is not sufficient to mean portable, and means portable at a level that an individual (a standard adult) can carry relatively easily. Examples of the portable devices include mobile phones, smart phones, tablet computers, notebook computers, various wearable devices, digital cameras, digital video cameras, audio devices (portable music players, IC recorders, etc.), computers (electronic calculators, etc.), portable game machines, electronic dictionaries, electronic manuals, electronic books, in-vehicle information devices, portable radios, portable televisions, portable printers, portable scanners, portable modulators, and other portable electronic devices, and mechanical watches, pocket watches, flashlights, portable mirrors, and the like. Examples of the members constituting the portable electronic device include an optical film, a display panel, and the like used in an image display device such as a liquid crystal display and an organic EL display. The adhesive tape disclosed herein can be applied to various members in automobiles, home electric appliances, and the like, and is preferably used for fixing, joining, molding, decoration, protection, support, and the like of the members.

< method of Using adhesive tape >

In some preferred embodiments, the present invention also provides a method of using an adhesive tape, comprising the steps of: (1) bonding the adhesive tape to a resin plate; (2) The resin sheet to which the adhesive tape is adhered is subjected to a temperature of 120 to 160 ℃ and a pressure of 0.05 to 0.5MPa for a period of 2 to 180 seconds.

As described in the foregoing < adhesive tape >, the type of the resin sheet is not particularly limited, and in some preferred embodiments, the surface roughness of one side of the resin sheet to which the adhesive tape is to be bonded is 0.2 μm or less Rz or less 10 μm, preferably 0.5 μm or less Rz or less 8 μm; and in some preferred embodiments, one side of the resin sheet to which the adhesive tape is to be bonded has an acrylic coating.

Examples

Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited to these examples. The evaluation method in the examples is as follows. In the examples, unless otherwise specified, "parts" and "%" are weight-based chemicals used are commercially available unless otherwise specified.

(preparation of acrylic Polymer A1)

180 parts of n-Butyl Acrylate (BA), 5 parts of Acrylonitrile (AN), 10 parts of Acrylic Acid (AA) and 500 parts of toluene as a polymerization solvent are charged into a reaction vessel equipped with a stirrer, a thermometer, a nitrogen inlet pipe and a reflux condenser, stirred at 65 ℃ for 0.5 hour under a nitrogen atmosphere, and then 0.1 part of 2,2' -Azobisisobutyronitrile (AIBN) is charged as a thermal polymerization initiator, and reacted at 65 to 85 ℃ for 6 to 8 hours to obtain a solution of AN acrylic polymer A1. The Mw of the soluble portion of the acrylic polymer A1 was 60 ten thousand.

(Source of polyurethane)

Polyurethane is commercially available as SH-101 (manufactured by Toyo ink).

< production of adhesive tape >

Example 1

To the polyurethane solution, 2 parts of a modified isocyanate (trade name "cornonate HX" manufactured by japan polyurethane industry company) as a crosslinking agent was added to 100 parts of the polyurethane contained in the solution, and the mixture was uniformly mixed to prepare an adhesive composition C1.

An adhesive composition C1 was applied to a first side (silicon-treated side) of a PET polyester release film having a thickness of 10 μm as an engineering material, and then heated at 130 ℃ for 2 minutes to form an adhesive layer having a thickness of 20 μm, and then the adhesive layer was attached to a base layer PC (polycarbonate) film having a thickness of 50 μm, thereby obtaining an adhesive tape.

Examples 2 to 7 and comparative examples 1 to 3

An adhesive tape was obtained in the same manner as in example 1, except that the thicknesses and types of the base material layer and the adhesive layer were changed as shown in table 1.

Specific types and thicknesses of the base material layer and the adhesive layer in the adhesive tapes of examples 1 to 7 and comparative examples 1 to 3 are shown in table 1.

TABLE 1

In Table 1, PC is polycarbonate, PMMA is polymethyl methacrylate, PVC is polyvinyl chloride, PET is polyethylene terephthalate, and PU is polyurethane.

Table 2 below shows the properties of the substrate layer.

TABLE 2

(use of adhesive tape)

The adhesive tapes of examples 1 to 7 and comparative examples 1 to 3 were adhered to a resin plate; and subjecting the resin sheet bonded with the adhesive tape to a temperature of 130 ℃ and a pressure of 0.25MPa in a mold for 40s, the resin sheet being shaped as required by the mold addition.

Resin plates used in examples and comparative examples are as follows.

Resin plate 1: the PC resin plate with the thickness of 1mm has an acrylic texture coating on the contact surface of the adhesive tape, and the surface roughness rz=6 mu m.

Resin plate 2: the PMMA/PC resin plate with the thickness of 1mm has an adhesive tape contact surface which is an acrylic texture coating and has the surface roughness rz=9 mu m.

Resin plate 3: the PMMA/PC resin plate with the thickness of 2mm has a contact surface of polyurethane texture coating and has the surface roughness rz=5 mu m.

Resin plate 4: the PMMA/PC resin plate with the thickness of 1mm has an adhesive tape contact surface which is an acrylic texture coating and has the surface roughness rz=15 mu m.

The performances of the adhesive tapes of examples 1 to 7 and comparative examples 1 to 3 and the practical performances after bonding to a resin plate were evaluated, and the results are shown in table 3.

TABLE 3 Table 3

In Table 3, the adhesion ratio refers to the ratio of the adhesion at room temperature (23 ℃) and the adhesion at 150℃for 2 minutes after the adhesive tape was adhered to the resin plate.

As shown in table 3, the adhesive tapes of examples 1 to 7, which meet the various requirements of the present invention, did not affect the surface of the resin sheet and were easily peeled off when adhered to the resin sheet under high temperature conditions. In contrast, when the adhesive tapes of comparative examples 1 to 3 were adhered to a resin sheet under high temperature conditions, residual adhesive appeared on the surface of the resin sheet, and the contact surface of the resin sheet had many wrinkles and flaws, which was not suitable for practical production.

< evaluation test >

(1) Thermal shrinkage after 30 minutes at 150 DEG C

According to ASTM D1204, an adhesive tape was cut into film samples (test pieces) of 120mm by 120mm, the label length was 100mm by 100mm, and the film was left in a hot environment at 150℃for 30 minutes, then left at room temperature (23 ℃) for 30 minutes, the dimensions of the label areas of the test pieces in the MD directions before and after heating were measured by a vernier caliper, and the heat shrinkage was determined using the following formula.

Heat shrinkage (%) = [ [ length before heating (mm) -length after heating (mm) ]/length before heating (mm) ] 100)

(2) Modulus of elasticity at 120 DEG C

The measurement was performed using a universal material tester (product name "AG-X plus electronic universal tester", manufactured by Shimadzu corporation, with a high-temperature test box). Specifically, a test piece was produced by cutting an adhesive tape into dimensions of 10mm wide and 250mm long, stretching the cut adhesive tape in a temperature oven at 120℃at a stretching speed of 300 mm/min, measuring a stress-strain curve at 120℃and calculating an elastic modulus at 120℃of the adhesive tape from stress data in a strain range of 5%.

(3) Elongation at break

The elongation was measured by using a universal material tester (product name "AG-X plus electronic universal tester" manufactured by Shimadzu corporation). Specifically, the adhesive tape was cut into pieces having a width of 20mm and a length of 150mm, and the pieces were stretched at a stretching speed of 300 mm/min to measure the value at break.

(4) Adhesion at room temperature

The adhesive tape was cut into test pieces 20mm wide by 150mm long. An SUS plate (SUS 430BA plate) cleaned with toluene was used as an adherend. The release liner covering the adhesive surface of each test piece was peeled off under a standard atmosphere of 50% RH at 23℃and a 2kg roller was reciprocated 1 time to press the exposed adhesive surface against the adherend. After the test piece thus pressed against the adherend under the above-described standard environment was left for 30 minutes, a universal material tester (product name "AG-X plus electronic universal tester manufactured by shimadzu corporation) was used at a drawing speed according to JIS Z0237: 300 mm/min, peel angle: peeling was performed at 180℃and the force required for the peeling (180℃peeling adhesion) (N/20 mm) was measured.

(5) Glass transition temperature (Tg)

About 5mg of the polymer constituting the adhesive layer in examples and comparative examples was taken and DSC measurement was performed under the following conditions.

Measurement device: TA Instruments, product name: q-2000

< measurement conditions >

Temperature program: 0 ℃ to 150 ℃ to 0 ℃ to 200 DEG C

Atmosphere gas: n (N) ₂ (50 mL/min)

Measuring speed: 10 ℃/min

(6) Tensile Strength

Tensile strength was determined according to ISO 527. Specifically, cutting an experimental piece with the length of 10mm multiplied by 250mm, the distance between marked lines of the experimental piece is 50mm, the interval between clamps is 100mm, the tension speed is 300mm/min, the load and the elongation during stretch-breaking are the tensile strength and the elongation, and then converting the tensile strength and the elongation into standard units and taking data within 5% of the elongation to calculate the tensile modulus.

(7) Tensile modulus

The tensile modulus was determined according to (6).

(8) Heat shrinkage of substrate layer at 150 DEG C

The measurement was performed according to the measurement method described in (1) above.

(9) Surface roughness Rz

The surface roughness Rz was measured by referring to the JIS-B0601-1994 test method.

(10) Evaluation of practicality

The adhesive tape was adhered to a PC (polycarbonate) (3 mm thick) resin plate (the surface of which was coated with a hardened optical acrylic texture coating, rz=6 μm) with a rubber roller having a weight of 2 kg; the resin plate is put into a back shell mould of the mobile phone, subjected to the temperature of 130 ℃ and the pressure of 0.25MPa, and hot pressed for 40 seconds, and processed into the shape of the back shell of the mobile phone. And (5) peeling the adhesive removing tape after natural cooling.

In the process of evaluating the practicability, if the adhesive tape is easily peeled off by hand, the resin plate contacted with the adhesive tape after peeling is not deformed, the surface is not adhesive residue, and appearance defects such as wrinkles, scratches and the like are avoided, and the evaluation result is excellent.

If the peeling by hand is slightly difficult, peeling is not easy, but the resin plate is evaluated as good when no appearance is poor.

If the resin sheet has a slight degree of appearance defects such as wrinkles and flaws after peeling, or peeling is difficult, the resin sheet needs to be peeled off with force, and the resin sheet is evaluated as being medium.

The appearance of the resin sheet was evaluated as poor if it was deformed or if it was marked with wrinkles or scratches.

If the resin plate surface has residual glue, the contact surface of the resin plate has a plurality of wrinkles and scratches, and the evaluation is NG.

Claims

1. An adhesive tape comprising a substrate and an adhesive layer laminated on at least one side of the substrate, characterized in that the adhesive tape has a heat shrinkage of 2% or less after being left at 150 ℃ for 30 minutes, an elastic modulus of 0.2 to 0.6GPa at 120 ℃ and an elongation at break of 110 to 400%.

2. The adhesive tape according to claim 1, wherein a ratio of an adhesive force at room temperature after the adhesive tape is adhered to a resin plate to an adhesive force at 150 ℃ for 2 minutes is 0.5 to 0.85, wherein the adhesive force at room temperature is 0.3 to 1.2N/20mm.

3. The adhesive tape according to claim 1 or 2, characterized in that the adhesive tape has a glass transition temperature (Tg) of 140 to 160 ℃ as measured by Differential Scanning Calorimetry (DSC).

4. The adhesive tape according to claim 1 or 2, wherein the substrate layer comprises at least one selected from the group consisting of polycarbonate and polymethyl methacrylate; the thickness of the substrate layer is 20-100 mu m.

5. The adhesive tape according to claim 1 or 2, wherein the base material layer has a tensile strength of 55 to 120MPa, a tensile modulus of 2000 to 3000MPa, and a heat shrinkage at 150 ℃ of 0.5 to 0.7%.

6. The adhesive tape according to claim 1 or 2, wherein the adhesive layer is formed of an adhesive composition comprising an acrylic polymer or polyurethane as a base polymer; optionally, the adhesive composition further comprises a cross-linking agent; preferably, the content of the crosslinking agent is 0.2 to 10 parts by weight based on 100 parts by weight of the base polymer; the thickness of the adhesive layer is 3-50 μm.

7. The adhesive tape according to claim 6, wherein the acrylic polymer comprises, based on 100 parts by weight of the entire monomer components of the acrylic polymer: 70 to 93 parts by weight, preferably 80 to 90 parts by weight of a tacky monomer, 5 to 30 parts by weight, preferably 8 to 25 parts by weight of a hard monomer and 1 to 3 parts by weight of a copolymerizable monomer;

8. The method of using an adhesive tape according to any one of claims 1 to 7, comprising the steps of:

(1) Bonding the adhesive tape to a resin plate;

9. The method of using an adhesive tape according to claim 8, wherein the surface roughness of one side of the resin sheet to which the adhesive tape is to be bonded is 0.2 μm or less Rz or less 10 μm.

10. The method of using an adhesive tape according to claim 8 or 9, wherein one side of the resin sheet to which the adhesive tape is to be bonded has an acryl coating.