TW201936856A - Temperature-sensitive adhesive, temperature-sensitive adhesive sheet and temperature-sensitive adhesive tape - Google Patents

Abstract

Provided is a thermosensitive adhesive containing a base resin (A) and a carboxyl group-free side chain crystalline polymer (B), wherein the base resin (A) is a copolymer of a monomer mixture containing a carboxyl group-containing ethylenically unsaturated monomer (A1) and a (meth) acrylic acid ester (A2) having a hydrocarbon group having 4 to 7 carbon atoms, while the carboxyl group-free side chain crystalline polymer (B) is a polymer having a monomer component containing a (meth) acrylic acid ester (B1) having a linear alkyl group of 14 to 30 as the constitutional unit, and at a temperature above the melting point of the carboxyl group-free side chain crystalline polymer (B), the adhesion of the thermosensitive adhesive to the polyimide adherend decreases.

Description

 Temperature sensitive adhesive, temperature sensitive adhesive sheet and temperature sensitive adhesive tape  

The invention relates to a temperature sensitive adhesive, a temperature sensitive adhesive sheet and a temperature sensitive adhesive tape.

A temperature sensitive resin having a temperature sensitive property in which a crystal state and a flow state are reversibly displayed in response to a temperature change is known. For example, Japanese Laid-Open Patent Publication No. Hei 6-510548 discloses a temperature sensitive adhesive containing such a resin. In the temperature sensitive adhesive, there is a warm-off type adhesive which can exert a fixing force at a temperature below the melting point of the temperature sensitive resin and at a melting point of the temperature sensitive resin. At the above temperatures, the adhesion is significantly reduced and peeled off.

For inorganic adhesives such as stainless steel sheets and glass, or polyimide-based adhesives, polyoxymethylene-based adhesives, polyethylene terephthalate-based adhesives, and polymethyl methacrylate An organic-based adhesive such as a polycarbonate or a polycarbonate-based adhesive is used. When the conventional heat-releasing adhesive is at a temperature equal to or higher than the melting point of the temperature-sensitive resin, the adhesive strength is remarkably lowered, and the adhesive can be easily peeled off. However, among the organic adherends, especially for the polyimide-based adhesive, the adhesive strength does not decrease even at a temperature higher than the melting point of the temperature sensitive resin. As a result, when a conventional heat-peelable adhesive is used for the polyimide-based adhesive, it is difficult to peel off the adhesive.

An object of the present invention is to provide a temperature sensitive adhesive and a temperature sensitive adhesive sheet and a temperature sensitive adhesive tape containing the temperature sensitive adhesive, wherein the temperature sensitivity is applied to a polyimide-based adhesive. The adhesive can be firmly adhered at room temperature, and the adhesive force is lowered at a temperature higher than the melting point of the temperature sensitive resin, and the adhesive can be easily peeled off.

The inventors of the present invention have found a solution including the following configuration in order to solve the above problems and have completed the present invention.

(1) A temperature sensitive adhesive comprising a base resin (A) and a carboxyl group-free side chain crystalline polymer (B), wherein the base resin (A) is a carboxyl group-containing ethylenically unsaturated monomer a copolymer of a monomer mixture of (A1) and a (meth) acrylate (A2) having a hydrocarbon group of 4 to 7 and a carboxyl group-free side chain crystalline polymer (B) having a carbon number of 14 a monomer component of a (meth) acrylate (B1) of a linear alkyl group of up to 30, which is a polymer of a constituent unit, and the temperature sensitive adhesive is a side chain crystalline polymer (B) containing no carboxyl group. When the temperature is higher than the melting point, the adhesion to the polyimide-based adhesive is lowered.

(2) The temperature sensitive adhesive according to the above (1), wherein the monomer component of the carboxyl group-free side chain crystalline polymer (B) is contained in a ratio of 30 to 70% by mass (meth) The acrylate (B1) further contains a (meth) acrylate (B2) having an alkyl group having 1 to 6 carbon atoms in a ratio of 30 to 70% by mass.

(3) The temperature sensitive adhesive according to the above (1) or (2), wherein the side chain crystalline polymer (B) having no carboxyl group has a weight average molecular weight of from 3,000 to 30,000.

(4) The temperature sensitive adhesive according to any one of the above (1) to (3), further comprising a crosslinking agent.

(5) The temperature-sensitive adhesive according to any one of the above-mentioned (1), wherein the polyimide-based adherend has an adhesive strength of 2 N/25 mm or more at 23 ° C. When the temperature is higher than the melting point of the side chain crystalline polymer, it has an adhesive strength of 0.05 N/25 mm or less.

(6) A temperature sensitive adhesive sheet comprising the temperature sensitive adhesive according to any one of the above (1) to (5).

(7) A temperature sensitive adhesive tape comprising an adhesive layer containing the temperature sensitive adhesive according to any one of the above (1) to (5), formed on at least one surface of the substrate.

According to the present invention, the adhesive of the polyimide-based adhesive can be firmly adhered at room temperature, and at a temperature equal to or higher than the melting point of the temperature-sensitive resin, the adhesive strength is lowered, and the adhesive can be easily peeled off. That is, the temperature at which the melting point of the temperature sensitive resin is not reached at room temperature is exhibited by the adhesion of the base resin (A) and the cohesive force of the side chain-chain crystalline polymer (B) which does not contain a carboxyl group. Adhesiveness. On the other hand, at a temperature higher than the melting point of the temperature sensitive resin, the surface free energy changes depending on the contact angle of the polyimide and the temperature sensitive resin. Therefore, the interfacial interaction between the polyimide-based adhesive and the temperature-sensitive resin is small, the peeling property is improved, and the stress is concentrated on the molten temperature-sensitive resin dispersed on the surface of the base resin, so that the interface is easily peeled off.

A temperature sensitive adhesive according to an embodiment of the present invention will be described in detail. The temperature sensitive adhesive according to one embodiment comprises a base resin (A) and a carboxyl group-free side chain crystalline polymer (B), and a side chain crystalline polymer (B) having no carboxyl group (equivalent to a feeling) When the temperature above the melting point of the warm resin) is lowered, the adhesion is lowered. In the present specification, "(meth)acrylic" means "acrylic acid" or "methacrylic acid".

The base resin (A) is a copolymer containing a carboxyl group-containing ethylenically unsaturated monomer (A1) and a (meth) acrylate (A2) having a hydrocarbon group of 4 to 7 carbon atoms as a monomer mixture. By using such a specific copolymer as the base resin (A), it is possible to exhibit special adhesion and releasability to the polyimide-based adherend.

The carboxyl group-containing ethylenically unsaturated monomer (A1) may, for example, be an unsaturated monocarboxylic acid, an unsaturated dicarboxylic acid or a carboxyl group-containing unsaturated ester.

Examples of the unsaturated monocarboxylic acid include acrylic acid, methacrylic acid, crotonic acid and the like. Examples of the unsaturated dicarboxylic acid include, for example, itaconic acid, maleic acid, and fumaric acid. The carboxyl group-containing unsaturated ester may, for example, be β-carboxyethyl acrylate or the like. The carboxyl group-containing ethylenically unsaturated monomer (A1) may be used alone or in combination of two or more. Among the carboxyl group-containing ethylenically unsaturated monomers (A1), acrylic acid and methacrylic acid are preferred from the viewpoint of further improving the adhesion to the polyimide-based adherend and peeling off more easily during peeling. Beta-carboxyethyl acrylate. In the monomer mixture, the carboxyl group-containing ethylenically unsaturated monomer (A1) is preferably contained in a ratio of from 0.1 to 30% by mass, more preferably from 1 to 20% by mass.

The (meth) acrylate (A2) having a hydrocarbon group having 4 to 7 carbon atoms is not particularly limited, and examples thereof include n-butyl (meth)acrylate and isobutyl (meth)acrylate. Base) tert-butyl acrylate, n-amyl (meth)acrylate, isoamyl (meth)acrylate, third amyl (meth)acrylate, n-hexyl (meth)acrylate, (meth)acrylic acid Ester, third hexyl (meth)acrylate, n-heptyl (meth)acrylate, isoheptyl (meth)acrylate, benzyl (meth)acrylate, cyclohexyl (meth)acrylate, and the like. The (meth) acrylate (A2) having a hydrocarbon group having 4 to 7 carbon atoms may be used alone or in combination of two or more. Among the (meth) acrylates (A2) having a hydrocarbon group having 4 to 7 carbon atoms, it is preferred from the viewpoint of further improving the adhesion to the polyimide-based adherend and peeling off more easily during peeling. N-butyl acrylate, isobutyl acrylate, and tert-butyl acrylate. In the monomer mixture, it is preferred to contain the (meth) acrylate (A2) having a hydrocarbon group having 4 to 7 carbon atoms in a ratio of 70 to 99.9% by mass, more preferably 80 to 99% by mass.

The monomer mixture may contain other monomers copolymerizable with the carboxyl group-containing ethylenically unsaturated monomer (A1) and the (meth) acrylate (A2) having a hydrocarbon group of 4 to 7 carbon atoms. Examples of such other monomers include an ethylenically unsaturated monomer having a hydroxyl group, an ethylenically unsaturated monomer having an epoxy group, an ethylenically unsaturated monomer having an isocyanate group, and having a carbon number. a (meth) acrylate having 8 or more alkyl groups, a (meth) acrylate having a cyclic hydrocarbon group having 8 or more carbon atoms, a (meth) acrylate having an oxyethyl group, and an oxypropyl group ( Methyl) acrylate, (meth) acrylate having a fluorine atom in the molecule, (meth) acrylamide or the like.

Examples of the ethylenically unsaturated monomer having a hydroxyl group include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate. 2-hydroxyhexyl methacrylate, 2-hydroxyethyl acrylamide, and the like. Examples of the ethylenically unsaturated monomer having an epoxy group include glycidyl (meth)acrylate and the like. The ethylenically unsaturated monomer having an isocyanate group may, for example, be 2-isocyanatoethyl (meth)acrylate. Examples of the (meth) acrylate having an oxyethyl group include methoxyethyl (meth)acrylate, ethoxyethoxyethyl (meth)acrylate, and (meth)acrylic acid. Oxyethylene triethylene glycol ester, phenoxyethyl (meth)acrylate, and the like. The (meth) acrylate having an oxypropyl group may, for example, be a polypropylene glycol (meth)acrylate or the like. Examples of the (meth) acrylate having a fluorine atom in the molecule include 2,2,2-trifluoroethyl (meth)acrylate and 2,2,3,3-tetrafluoro(meth)acrylate. Propyl ester, 1H, 1H, 5H-octafluoropentyl (meth)acrylate, and the like. Examples of the (meth) acrylate having an alkyl group having 8 or more carbon atoms include ethyl hexyl (meth) acrylate, lauryl (meth) acrylate, and cetyl (meth) acrylate. Stearyl methacrylate, behenyl (meth) acrylate, and the like. The (meth) acrylate having a cyclic hydrocarbon group having 8 or more carbon atoms may, for example, be isodecyl (meth)acrylate.

The polymerization method for obtaining the monomer mixture of the base resin (A) is not particularly limited, and examples thereof include a solution polymerization method, a bulk polymerization method, a suspension polymerization method, and an emulsion polymerization method. For example, when the solution polymerization method is used, the monomer mixture and the solvent are mixed, and if necessary, a polymerization initiator and a chain transfer agent are added, and the mixture is reacted at about 50 to 100 ° C for about 1 to 24 hours while stirring.

The weight average molecular weight (Mw) of such a base resin (A) is not particularly limited. The base resin (A) preferably has a weight average molecular weight of from 100,000 to 2,000,000, more preferably from 200,000 to 1,000,000.

The carboxyl group-free side chain crystalline polymer (B) (hereinafter, simply referred to as "side chain crystalline polymer (B)") is a polymer having no carboxyl group in the molecule. The side chain crystalline polymer (B) is a monomer component containing a (meth) acrylate (B1) having a linear alkyl group having 14 to 30 carbon atoms as a constituent unit. Examples of the (meth) acrylate (B1) having a linear alkyl group having 14 to 30 carbon atoms include, for example, cetyl (meth) acrylate, stearyl (meth) acrylate, and (methyl). Ethylene acrylate, behenyl (meth)acrylate, tris (meth)acrylate, and the like. Among such (meth) acrylates (A), a (meth) acrylate having a linear alkyl group having 18 to 22 carbon atoms is preferred. The (meth) acrylate (B1) having a linear alkyl group having 14 to 30 carbon atoms may be used alone or in combination of two or more.

The monomer component constituting the side chain crystalline polymer (B) is not particularly limited as long as it contains the (meth) acrylate (B1). However, in order to prevent the carboxyl group-containing polymer (B) from having a carboxyl group in the molecule, the above-mentioned carboxyl group-containing ethylenically unsaturated monomer such as (meth)acrylic acid or the like is not used as the monomer component. In addition to the (meth) acrylate (B1), the monomer component may contain, for example, a (meth) acrylate (B2) having an alkyl group having 1 to 6 carbon atoms.

Examples of the (meth) acrylate (B2) having an alkyl group having 1 to 6 carbon atoms include methyl (meth) acrylate, ethyl (meth) acrylate, and propyl (meth) acrylate. Isopropyl (meth)acrylate, butyl (meth)acrylate, and the like.

The monomer component constituting the side chain crystalline polymer (B) preferably contains a linear chain having a carbon number of 14 to 30 in a ratio of 30 to 70% by mass, more preferably 40 to 60% by mass. Alkyl (meth) acrylate (B1). It is preferable to contain the (meth) acrylate (B2) having an alkyl group having 1 to 6 carbon atoms in a ratio of 30 to 70% by mass, more preferably 40 to 60% by mass.

The polymerization method for obtaining the monomer component of the side chain crystalline polymer (B) is not particularly limited, and examples thereof include a solution polymerization method, a bulk polymerization method, a suspension polymerization method, and an emulsion polymerization method. For example, when the solution polymerization method is used, the monomer component and the solvent are mixed, and if necessary, a polymerization initiator or a chain transfer agent is added, and the reaction is carried out at about 50 to 100 ° C for about 1 to 6 hours while stirring.

The weight average molecular weight (Mw) of the side chain crystalline polymer (B) is not particularly limited. The side chain crystalline polymer (B) preferably has a weight average molecular weight of from 3,000 to 30,000, more preferably from 6,000 to 15,000.

When the side chain crystalline polymer (B) has a temperature higher than the melting point (Tm), the adhesion is lowered. That is, the side chain crystalline polymer (B) crystallizes at a temperature not reaching the melting point, and the phase transition at a temperature higher than the melting point exhibits fluidity. The melting point of the side chain crystalline polymer is not particularly limited. The side chain crystalline polymer preferably has a melting point of 70 ° C or less, more preferably a melting point of 60 ° C or less. In the present specification, "melting point" means a temperature at which a specific portion of the polymer which is initially integrated in order is disordered according to a certain balancing procedure, and can be 10 ° C by a differential scanning calorimeter (DSC). The condition of /min is determined by measurement.

The temperature sensitive adhesive according to an embodiment of the present invention contains the base resin (A) and the side chain crystalline polymer (B) in an arbitrary ratio, preferably 100 parts by mass based on the base resin (A). The ratio of 30 parts by mass contains the side chain crystalline polymer (B), and more preferably contains the side chain crystalline polymer (B) in a proportion of 3 to 20 parts by mass. The temperature sensitive adhesive according to an embodiment of the present invention is obtained by mixing and stirring a base resin (A) and a side chain crystalline polymer (B).

Further, the temperature sensitive adhesive according to an embodiment of the present invention may contain a crosslinking agent for enhancing the cohesive force. The crosslinking agent is not particularly limited, and examples thereof include an aziridine compound, an epoxy compound, a metal chelate compound, a metal alkoxide compound, and an isocyanate compound. Among them, a metal chelate compound is suitable. By using the metal chelate compound, the dissipation of the peeling energy in the high temperature region is suppressed, and the resistance at the time of peeling is easily suppressed.

A temperature sensitive adhesive according to an embodiment of the present invention may be added with a plasticizer, a tackifier, a filler, an antioxidant, or the like as needed. Examples of the tackifier include a special rosin ester system, a terpene phenol system, a petroleum resin system, a high hydroxyl value rosin ester system, and a hydrogenated rosin ester system. Further, in order to further improve the adhesion to the polyimide-based adhesive, a general pressure-sensitive adhesive such as an acrylic or rubber-based adhesive may be added.

The temperature sensitive adhesive according to an embodiment of the present invention preferably has a bonding strength of 2N/25 mm or more at 23 ° C and a melting point of the side chain crystalline polymer (B) for the polyimide-based adhesive. The above temperature has an adhesive strength of 0.05 N/25 mm or less. In the present specification, the adhesion strength is measured in accordance with JIS Z0237 and measured at 300 mm/min, and is a value for a polyimide-based adhesive. If the temperature sensitive adhesive has such a range of adhesive strength, the polyimide-based adhesive can be more strongly adhered at room temperature (the temperature at which the melting point of the side chain crystalline polymer (B) is not reached), and The temperature above the melting point of the side chain crystalline polymer (B) is more likely to cause the adhesive to be peeled off from the polyimide-based adherend. The temperature sensitive adhesive preferably has an adhesive strength of 5 N/25 mm or more at 23 ° C and an adhesive strength of 0.05 N/25 mm or less at a temperature higher than the melting point of the side chain crystalline polymer (B).

When the temperature sensitive adhesive is peeled off, it is often peeled off at a higher speed (for example, about 3000 mm/min) than the speed specified by JIS. Generally, when peeling at a high speed, the peeling strength tends to become high. However, when the peel strength of 300 mm/min prescribed by JIS is sufficiently low to 0.05 N/25 mm or less, even if peeling is performed at a high speed, peeling strength hardly rises. Therefore, the temperature sensitive adhesive of one embodiment can be peeled off without causing damage to the polyimide-based adherend regardless of the peeling speed.

The method of using the temperature sensitive adhesive according to the embodiment of the present invention is not particularly limited. For example, the temperature sensitive adhesive can be applied to the target polyimide-based adhesive, and the temperature sensitive adhesive can be adhered. The agent is formed into a sheet shape and used as a substrate without a tape.

Alternatively, it may be used in the form of a temperature sensitive adhesive tape having an adhesive layer containing a temperature sensitive adhesive according to an embodiment of the present invention formed on at least one side of the substrate. The substrate is preferably in the form of a film, and the film also includes a sheet. The constituent material of the substrate may, for example, be polyethylene, polyethylene terephthalate, polyethylene naphthalate, polypropylene, polyester, polyamine, polyimine, polyfluorene. A synthetic resin such as an amine imine, a polycarbonate, an ethylene vinyl acetate copolymer, an ethylene ethyl acrylate copolymer, an ethylene polypropylene copolymer, a polyvinyl chloride or a polyether ether ketone.

The substrate may have a single layer construction or a multilayer construction. The substrate usually has a thickness of about 5 to 500 μm. Further, in order to improve the adhesion to the adhesive layer, the substrate may be subjected to surface treatment such as corona discharge treatment, plasma treatment, sandblasting treatment, chemical etching treatment, primer treatment or the like.

The method of forming the pressure-sensitive adhesive layer containing the temperature sensitive adhesive on at least one surface of the substrate is not particularly limited. For example, a coating liquid in which a solvent is added to a temperature sensitive adhesive as needed, and a method of applying it to one side or both sides of a substrate by an applicator or the like and drying it may be mentioned. The applicator may, for example, be a knife coater, a roll coater, a calender coater, a slap coater, a gravure coater, a rod coater or the like. The thickness of the adhesive layer is not particularly limited. The adhesive layer preferably has a thickness of about 1 to 500 μm, more preferably a thickness of about 5 to 60 μm.

a temperature sensitive adhesive tape having a pressure sensitive adhesive layer on one surface of the substrate alone, and a pressure sensitive adhesive layer on the other surface, for example, or a temperature sensitive adhesive and A layer of pressure sensitive adhesive. The pressure-sensitive adhesive may, for example, be a natural rubber adhesive, a synthetic rubber adhesive, a styrene-butadiene latex base adhesive, a block copolymer type thermoplastic rubber, a butyl rubber, a polyisobutylene, or an acrylic acid. Agent, vinyl ether copolymer, and the like. Commercially available products can be used as the pressure-sensitive adhesive.

According to the temperature-sensitive adhesive of the embodiment of the present invention, the adhesion of the polyimide-based adhesive to the temperature above the melting point of the temperature sensitive resin is remarkably lowered, and the adhesive can be easily peeled off. That is, it exhibits special adhesion and peelability to the polyimide-based adhesive. Therefore, by using the temperature sensitive adhesive of one embodiment of the present invention, the polyimide-based adherend can be fixed at room temperature and the polyimide-based adherend can be processed. After the processing, the temperature-sensitive adhesive can be easily peeled off from the polyimide-based adhesive by raising the temperature to a temperature equal to or higher than the melting point of the side chain crystalline polymer (B) contained in the temperature sensitive adhesive. The temperature sensitive adhesive sheet and the temperature sensitive adhesive tape having the temperature sensitive adhesive of one embodiment of the present invention are also used.

The temperature sensitive adhesive, the temperature sensitive adhesive sheet, and the temperature sensitive adhesive tape according to an embodiment of the present invention are used, for example, in a carrier tape, a masking tape, or a dicing. Fixation, fixing during transfer process, etc.

 [Examples]  

Hereinafter, the present invention will be specifically described by way of examples and comparative examples, but the present invention is not limited to the examples.

(Synthesis Example A1: Synthesis of Basic Resin)

As shown in Table 1, 92% by mass of n-butyl acrylate was mixed with 8% by mass of acrylic acid to obtain a monomer mixture. 0.5 parts by mass of PERBUTYL ND (manufactured by Nippon Oil Co., Ltd.) as a polymerization initiator and 230 parts by mass of methyl acetate as a solvent were added in proportion to 100 parts by mass of the monomer mixture, and polymerization was carried out at 55 ° C. hour. Then, the temperature was raised to 80 ° C, and 0.5 parts by mass of PERHEXYL PV (manufactured by Nippon Oil Co., Ltd.) as a polymerization initiator was added in proportion to 100 parts by mass of the monomer mixture. After the addition, the polymerization was carried out for 2 hours to obtain a copolymer (base resin). The resulting base resin had a weight average molecular weight (Mw) of about 400,000.

(Synthesis Examples A2 to A6: Synthesis of Base Resin)

A copolymer (base resin) was obtained in the same manner as in Synthesis Example A1 except that the monomer components described in Table 1 were used in the ratios shown in Table 1. The Mw of each of the base resins is shown in Table 1.

(Comparative Synthesis Examples A1 to A3: Synthesis of Basic Resin)

A copolymer (base resin) was obtained in the same manner as in Synthesis Example A1 except that the monomer components described in Table 1 were used in the ratios shown in Table 1. The Mw of each of the base resins is shown in Table 1.

C4A: n-butyl acrylate

AA: Acrylic

βCEA: β-carboxyethyl acrylate

EHA: ethylhexyl acrylate

C1A: Methyl acrylate

HEA: 2-hydroxyethyl acrylate

(Synthesis Example B1: Synthesis of Side Chain Crystalline Polymer)

As shown in Table 2, 45 mass% of behenyl acrylate (manufactured by Nippon Oil Co., Ltd.) was mixed with 55 mass% of methyl acrylate to obtain a monomer mixture. 1 part by mass of PERHEXYL PV (manufactured by Nippon Oil Co., Ltd.) as a polymerization initiator and 1 part by mass of dodecyl mercaptan (manufactured by Tokyo Chemical Industry Co., Ltd.) were added in proportion to 100 parts by mass of the monomer mixture. The mixture and 100 parts by mass of toluene as a solvent were polymerized at 80 ° C for 3 hours to obtain a copolymer (side chain crystalline polymer). The resulting side chain crystalline polymer has a weight average molecular weight (Mw) of about 8,000 and a melting point (Tm) of about 50 °C.

(Synthesis Examples B2 and B3: Synthesis of Side Chain Crystalline Polymer)

A copolymer (side chain crystalline polymer) was obtained in the same manner as in Synthesis Example B1 except that the monomer components described in Table 2 were used in the ratios shown in Table 2. The Mw and Tm of each side chain crystalline polymer are shown in Table 2.

(Comparative Synthesis Examples B1 and B2: Synthesis of Side Chain Crystalline Polymer)

A copolymer (side chain crystalline polymer) was obtained in the same manner as in Synthesis Example B1 except that the monomer components described in Table 2 were used in the ratios shown in Table 2. The Mw and Tm of each side chain crystalline polymer are shown in Table 2.

C22A: behenyl acrylate

C1A: Methyl acrylate

C18A: stearyl acrylate

AA: Acrylic

(Example 1)

The side chain crystalline polymer obtained in Synthesis Example B1 was mixed in an amount of 5 parts by mass based on 100 parts by mass of the base resin obtained in Synthesis Example A1 to obtain a temperature sensitive adhesive. The temperature sensitive adhesive thus obtained was dissolved in ethyl acetate so as to have a concentration of 30% by mass to prepare a temperature sensitive adhesive solution. In the obtained solution, a metal ruthenium crosslinking agent (aluminum triacetate, manufactured by Kawasaki Fine Chemicals Co., Ltd.) as a crosslinking agent is added in an amount of 1 part by mass based on 100 parts by mass of the base resin. A temperature sensitive adhesive composition is obtained. The obtained temperature sensitive adhesive composition was applied to one side of a substrate (PET film having a thickness of 100 μm) to form an adhesive layer. The adhesive layer has a thickness of 30 μm. In this way, a temperature sensitive adhesive tape is obtained.

The adhesion strength of the obtained temperature sensitive adhesive tape was measured in accordance with JIS Z0237. Specifically, the temperature sensitive adhesive tape was cut into a strip shape having a width of 25 mm, and attached to an adherend formed of polyimine using a 2 kg roller. The sample was allowed to stand at 23 ° C for 20 minutes, and the temperature-sensitive adhesive tape was peeled off at 180 ° using a force measuring device at a speed of 300 mm/min. The sample peeled off at the adhesive/adhered interface without residue was measured at 23 ° C. The strength of the time. The resulting strength was evaluated according to the following criteria, and it was evaluated as having sufficient fixation when belonging to A or B. The results are shown in Table 3.

 <Evaluation Benchmark>  

A: When the strength is 5 N/25 mm or more.

B: When the strength is 2 N/25 mm or more and less than 5 N/25 mm.

C: When the strength is less than 2N/25mm.

Next, the steps up to stand at 20 ° C for 20 minutes were carried out in the same manner as described above. Thereafter, the mixture was allowed to stand at 60 ° C for 20 minutes, and the temperature-sensitive adhesive tape was peeled off at 180 ° using a force measuring device at a speed of 300 mm / minute, and the bonding strength at 60 ° C was measured. The resulting bond strength was evaluated according to the following criteria, and it was evaluated as having sufficient peelability when belonging to A or B. The results are shown in Table 3.

 <Evaluation Benchmark>  

A: When the strength is 0.05 N/25 mm or less.

B: When the strength is more than 0.05 N/25 mm and 0.1 N/25 mm or less.

C: When the strength exceeds 0.1 N/25 mm.

(Examples 2 to 8)

A temperature sensitive adhesive was obtained in the same manner as in Example 1 except that the base resin and the side chain crystalline polymer shown in Table 3 were used in the proportions shown in Table 3. A temperature sensitive adhesive composition was obtained in the same manner as in Example 1 except that the obtained temperature sensitive adhesive was used. A temperature sensitive adhesive tape was obtained in the same manner as in Example 1 except that the obtained temperature sensitive adhesive composition was used. The adhesive layer of the temperature sensitive adhesive tape has a thickness of 30 μm. With respect to each of the temperature-sensitive adhesive tapes obtained in Examples 2 to 8, the adhesion strength at 23 ° C and 60 ° C was measured in the same manner as in Example 1. The results are shown in Table 3.

(Comparative Examples 1 to 6)

A temperature sensitive adhesive was obtained in the same manner as in Example 1 except that the base resin and the side chain crystalline polymer shown in Table 3 were used in the proportions shown in Table 3. The obtained temperature-sensitive adhesive was dissolved in ethyl acetate so as to have a concentration of 30% by mass, and compared with 100 parts by mass of the base resin in a ratio of 1 part by mass in Comparative Examples 1 to 3, In Examples 4 to 6, a metal ruthenium crosslinking agent (aluminum triacetate, manufactured by Kawasaki Fine Chemicals Co., Ltd.) was added in a ratio of 2 parts by mass to obtain a temperature sensitive adhesive composition. A temperature sensitive adhesive tape was obtained in the same manner as in Example 1 except that the obtained temperature sensitive adhesive composition was used. The adhesive layer of the temperature sensitive adhesive tape has a thickness of 30 μm. With respect to each of the temperature-sensitive adhesive tapes obtained in Comparative Examples 1 to 6, the adhesion strength at 23 ° C and 60 ° C was measured in the same manner as in Example 1. The results are shown in Table 3.

(Comparative Examples 7 and 8)

A temperature sensitive adhesive was obtained in the same manner as in Example 1 except that the base resin and the side chain crystalline polymer shown in Table 3 were used in the proportions shown in Table 3. The obtained temperature sensitive adhesive was dissolved in ethyl acetate so as to have a concentration of 30% by mass, and an isocyanate crosslinking agent (Coronate L45, was added in an amount of 1 part by mass based on 100 parts by mass of the base resin. TOSOH (stock) system, to obtain a temperature sensitive adhesive composition. A temperature sensitive adhesive tape was obtained in the same manner as in Example 1 except that the obtained temperature sensitive adhesive composition was used. The adhesive layer of the temperature sensitive adhesive tape has a thickness of 30 μm. With respect to each of the temperature-sensitive adhesive tapes obtained in Comparative Examples 1 to 8, the adhesion strength at 23 ° C and 60 ° C was measured in the same manner as in Example 1. The results are shown in Table 3.

As shown in Table 3, it was found that the temperature-sensitive adhesive (temperature-sensitive adhesive tape) obtained in Examples 1 to 8 was sufficient at 23 ° C (room temperature) for the adherend formed of polyimide. The fixability is sufficient at 60 ° C (temperature above the melting point of the side chain crystalline polymer). Therefore, the temperature sensitive adhesive (temperature sensitive adhesive tape) obtained in Examples 1 to 8 can sufficiently fix the polyimide-based adhesive at room temperature, and the temperature is higher than the melting point of the side chain crystalline polymer. It can be easily peeled off from the polyimide-based adhesive.

On the other hand, Comparative Example 1 did not use a side chain crystalline polymer, Comparative Examples 2, 3, 6 and 8 used a side chain crystalline polymer having a carboxyl group in the molecule, and Comparative Examples 4 to 8 did not contain a carbon number of 4. As a base resin, a copolymer of a monomer mixture of a (meth) acrylate (A2) to a hydrocarbon group of 7. Therefore, it was found that at least one of the fixability and the peeling property of the temperature sensitive adhesive (temperature sensitive adhesive tape) obtained in Comparative Examples 1 to 8 was poor for the adherend formed of polyimide.

Claims (7)

 A thermosensitive adhesive comprising a base resin (A) and a carboxyl group-free side chain crystalline polymer (B), wherein the base resin (A) is a carboxyl group-containing ethylenically unsaturated monomer (A1) And a copolymer of a monomer mixture of a (meth) acrylate (A2) having a hydrocarbon group of 4 to 7 carbon atoms, and a carboxyl group-free side chain crystalline polymer (B) having a carbon number of 14 to 30 a monomer component of a linear alkyl (meth) acrylate (B1) as a constituent unit, and the temperature sensitive adhesive is at least a melting point of a carboxyl group-free side chain crystalline polymer (B). At the temperature, the adhesion to the polyimide-based adhesive is lowered.    The temperature sensitive adhesive according to the first aspect of the invention, wherein the monomer component of the carboxyl group-free side chain crystalline polymer (B) contains the above (meth) in a ratio of 30 to 70% by mass. The acrylate (B1) further contains a (meth) acrylate (B2) having an alkyl group having 1 to 6 carbon atoms in a ratio of 30 to 70% by mass.    The temperature sensitive adhesive according to claim 1, wherein the carboxyl group-free side chain crystalline polymer (B) has a weight average molecular weight of 3,000 to 30,000.    The temperature sensitive adhesive according to claim 1 of the patent application further contains a crosslinking agent.    The temperature-sensitive adhesive according to the first aspect of the invention, wherein the polyimide-based adhesive has an adhesive strength of 2 N/25 mm or more at 23 ° C, and the side chain crystalline polymer When the temperature is higher than the melting point, it has an adhesive strength of 0.05 N/25 mm or less.    A temperature sensitive adhesive sheet comprising the temperature sensitive adhesive according to any one of claims 1 to 5.    A temperature sensitive adhesive tape comprising an adhesive layer containing the temperature sensitive adhesive according to any one of claims 1 to 5 on at least one side of the substrate.