TW201805393A - Temperature sensitive adhesive - Google Patents

Abstract

An object of the present invention is to provide a temperature sensitive adhesive which is excellent in releasability after being exposed to a high temperature atmosphere. The temperature sensitive adhesive comprises a first side chain crystalline polymer, which has a reduced adhesive strength at a temperature lower than the melting point of the first side chain crystalline polymer, which further comprises a block copolymer composed of a silicone and an acrylic resin. The temperature sensitive adhesive has a glass-glass peel strength of 10 N/400 mm2 or less at an ambient temperature of 5 DEG C after being exposed to an ambient temperature of 230 DEG C for 30 minutes, and a glass-glass peel strength of 15 N/400 mm2 or less at an ambient temperature of 5 DEG C after being exposed to an ambient temperature of 250 DEG C for 60 minutes, measured as shown in FIG. 1.

Description

Thermosensitive adhesive

The present invention relates to a thermosensitive adhesive.

The temperature-sensitive adhesive contains a side-chain crystalline polymer as a main component, and if it is cooled to a temperature below the melting point of the side-chain crystalline polymer, the side-chain crystalline polymer crystallizes and the adhesive force decreases. The thermosensitive adhesive is processed into sheets, tapes, etc., and substrates made of glass, plastic, etc. are temporarily fixed in the manufacturing steps of touch sensors, organic EL elements (OLED), etc. in the field of flat panel displays (FPD). It is used at the time (for example, refer to Patent Document 1). The thermosensitive adhesive used in such applications is desired to have excellent peelability after exposure to a high-temperature environment.

[Prior technical literature] [Patent Literature]

Patent Document 1: Japanese Patent Application Laid-Open No. 2015-187238

An object of the present invention is to provide a temperature-sensitive adhesive having excellent peelability after exposure to a high-temperature environment.

The temperature-sensitive adhesive of the present invention is a temperature-sensitive adhesive containing a first side-chain crystalline polymer and having a reduced adhesive force at a temperature lower than the melting point of the first side-chain crystalline polymer, and further contains A block copolymer containing silicone and acrylic resin.

According to the present invention, there is an effect that the peelability after being exposed to a high-temperature environment is excellent.

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FIG. 1 is a schematic explanatory diagram showing a method for measuring a glass-to-glass peel strength in an example.

<Thermal adhesive>

Hereinafter, a temperature-sensitive adhesive according to an embodiment of the present invention will be described in detail.

The temperature-sensitive adhesive of this embodiment contains a side chain crystalline polymer. The side chain crystalline polymer is a polymer having a melting point. Melting point refers to the temperature at which a specific part of a polymer initially integrated into an ordered arrangement becomes disordered through an equilibrium process, and is measured under a measurement condition of 10 ° C / minute using a differential scanning calorimeter (DSC) Value.

The side-chain crystalline polymer crystallizes at a temperature lower than the melting point, and undergoes phase transfer at a temperature above the melting point to show a flow. Mobility. That is, the side-chain crystalline polymer has temperature sensitivity that reversibly produces a crystalline state and a flowing state in response to a temperature change.

(First side chain crystalline polymer)

The temperature-sensitive adhesive of the present embodiment contains the first side-chain crystalline polymer composed of the above-mentioned side-chain crystalline polymer, and has an adhesive force at a temperature lower than the melting point of the first side-chain crystalline polymer. reduce. In other words, the temperature-sensitive adhesive of the present embodiment contains the first side-chain crystalline polymer at a rate at which the first side-chain crystalline polymer is reduced when the first side-chain crystalline polymer is crystallized at a temperature below the melting point. That is, the thermosensitive adhesive system of this embodiment contains a 1st side chain crystalline polymer as a main component. Therefore, when the adherend is peeled from the temperature-sensitive adhesive, if the temperature-sensitive adhesive is cooled to a temperature below the melting point of the first side chain crystalline polymer, the first side chain crystalline polymer crystallizes. The adhesion is reduced. In addition, if the temperature-sensitive adhesive is heated to a temperature higher than the melting point of the first side chain crystalline polymer, the first side chain crystalline polymer exhibits fluidity and the adhesive force is restored, so it can be reused.

The first side chain crystalline polymer contains, as a monomer component, a (meth) acrylate having a linear alkyl group having 16 or more carbon atoms. In the (meth) acrylate having a linear alkyl group having 16 or more carbon atoms, the linear alkyl group having 16 or more carbon atoms functions as a side chain crystalline site in the side chain crystalline polymer. That is, the side-chain crystalline polymer is a comb-shaped polymer having a linear alkyl group having 16 or more carbon atoms in the side chain, and its side chains are integrated into an orderly arrangement by intermolecular force or the like for crystallization. Into. Again, on The (meth) acrylate means acrylate or methacrylate.

Examples of the (meth) acrylate having a linear alkyl group having 16 or more carbon atoms include cetyl (meth) acrylate, octadecyl (meth) acrylate, and (meth) (Meth) acrylic acid esters having linear alkyl groups having 16 to 22 carbon atoms such as eicosyl acrylate and behenyl (meth) acrylate. The exemplified (meth) acrylates may be used alone or in combination of two or more. The monomer component preferably contains a (meth) acrylate having a linear alkyl group of 16 or more in a proportion of 10 to 90% by weight, and more preferably 20 to 80% by weight.

The monomer component may contain other monomers copolymerizable with a (meth) acrylate having a linear alkyl group having 16 or more carbon atoms. Examples of other monomers include (meth) acrylates having an alkyl group having 1 to 6 carbon atoms, and polar monomers.

Examples of the (meth) acrylate having an alkyl group having 1 to 6 carbon atoms include methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, and (meth) Hexyl acrylate and the like. The exemplified (meth) acrylates may be used alone or in combination of two or more. The (meth) acrylate containing an alkyl group having 1 to 6 carbons is preferably contained in the monomer component in a proportion of 10 to 90% by weight, more preferably 20 to 80% by weight.

Examples of the polar monomer include ethylenically unsaturated monomers having a carboxyl group such as acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid, and fumaric acid; 2-hydroxyethyl (meth) acrylate And ethylenically unsaturated monomers having a hydroxyl group such as 2-hydroxypropyl (meth) acrylate and 2-hydroxyhexyl (meth) acrylate. Exemplary polar monomers may be used alone or in combination. Use 2 or more types together. The monomer component preferably contains a polar monomer in an amount of 20% by weight or less, and more preferably 1 to 15% by weight.

The monomer component may further include a reactive fluorine compound. The reactive fluorine compound means a fluorine compound having a functional group showing reactivity. Examples of the functional group exhibiting reactivity include an epoxy group (including a glycidyl group and an epoxy cycloalkyl group), a mercapto group, a carbyl group (hydroxymethyl), a carboxyl group, a silanol group, a phenol group, and an amino group , Hydroxyl, groups having ethylenically unsaturated double bonds, and the like. Examples of the group having an ethylenically unsaturated double bond include a vinyl group, an allyl group, a (meth) acrylic group, a (meth) acrylfluorenyl group, a (meth) acrylfluorenyl group, and the like.

Specific examples of the reactive fluorine compound include a compound represented by the following general formula (I).

R ₁ -CF ₃ (I) [In the formula, the group represented by R ₁ is: CH ₂ = CHCOOR ² -or CH ₂ = C (CH ₃ ) COOR ^2- (wherein, R ² represents an alkylene group.) . ]

Examples of the alkylene group represented by R ² include those having 1 to 6 carbon atoms such as methylene, ethylene, trimethylene, propylene, tetramethylene, pentamethylene, and hexamethylene. Linear or branched alkylene, etc.

Specific examples of the compound represented by the general formula (I) include acrylic acid 2,2,2-trifluoroethyl ester represented by the following formula (Ia), and methacrylic acid 2, represented by the formula (Ib). 2,2-trifluoroethyl and the like.

As the reactive fluorine compound, a commercially available product can be used. Examples of commercially available reactive fluoro compounds include "Viscoat 3F", "Viscoat 3FM", "Viscoat 4F", "Viscoat 8F", "Viscoat 8FM", co-manufactured by Osaka Organic Chemical Industry Co., Ltd. "LIGHT ESTER M-3F" manufactured by Rongshe Chemical Co., Ltd.

The reactive fluorine compound may be used singly or in combination of two or more kinds. The monomer component preferably contains a reactive fluorine compound in an amount of 10% by weight or less, and more preferably in an amount of 5% by weight or less.

Preferred compositions of the first side chain crystalline polymer are 28 to 34% by weight of behenyl acrylate, 54 to 64% by weight of methyl acrylate, 4 to 6% by weight of acrylic acid, and formula (Ia) The acrylic acid is represented by 4 to 6% by weight of 2,2,2-trifluoroethyl ester. The first side chain crystalline polymer can maximize the proportion of methyl acrylate in the monomer component.

Examples of the polymerization method of the monomer component include a solution polymerization method, a block polymerization method, a suspension polymerization method, and an emulsion polymerization method. In the case of a solution polymerization method, a monomer component and a solvent may be mixed, a polymerization initiator, a chain transfer agent, etc. may be added as needed, and it may be made to react at about 40 to 90 ° C. for about 2 to 10 hours while stirring.

Weight average molecular weight of the first side chain crystalline polymer It is preferably larger than 100,000, more preferably 300,000 to 800,000, and still more preferably 400,000 to 700,000. The weight average molecular weight is a value measured by gel permeation chromatography (GPC), and the obtained measurement value is a polystyrene conversion value.

The melting point of the first side chain crystalline polymer is preferably 10 to 60 ° C, and more preferably 20 to 60 ° C. The melting point can be adjusted by changing the composition of the monomer component and the like.

(Block copolymer)

The temperature-sensitive adhesive of the present embodiment further contains a block copolymer (hereinafter sometimes referred to as a "block copolymer") containing polysiloxane and an acrylic resin. With such a configuration, the following effects can be obtained.

If the temperature-sensitive adhesive is cooled to a temperature lower than the melting point of the first side chain crystalline polymer, in addition to the decrease in the adhesion force caused by the crystallization of the first side chain crystalline polymer, it will increase due to the intercalation. The release property of the polysiloxane of the segment copolymer can sufficiently reduce the adhesive force. Therefore, when the temperature-sensitive adhesive of this embodiment is used, the following effects are obtained: when used as an adhesive for temporarily fixing a substrate in a manufacturing process such as a touch sensor or OLED, the conventional temperature-sensitive adhesive is used. In terms of adhesives, the adhesion between the base and the substrate gradually rises, and low-temperature peeling easily becomes difficult. In high-temperature environments exceeding 200 ° C, especially in high-temperature environments of 230 to 250 ° C, after long-term exposure, the peelability is also high. Excellent. Specifically, the temperature-sensitive adhesive according to the present embodiment is measured in a glass-glass room at an ambient temperature of 5 ° C. after being exposed to an ambient temperature of 230 ° C. for 30 minutes in a measurement method described in an Example described later. The peel strength is 10 N / 400 mm ² or less, and the glass-glass peel strength at an ambient temperature of 5 ° C. after exposure to an ambient temperature of 250 ° C. for 60 minutes is 15 N / 400 mm ² or less. Therefore, the temperature-sensitive adhesive of the present embodiment can be suitably used for temporary fixing of a substrate in a manufacturing process such as a touch sensor or an OLED.

When the temperature-sensitive adhesive contains a block copolymer, the following effects can be further obtained. That is, the block copolymer is caused by the acrylic resin and has excellent compatibility with the first side chain crystalline polymer which is an acrylic polymer, and therefore, it is difficult to precipitate on the surface of the thermosensitive adhesive. Therefore, since the substrate can be stably fixed, it is possible to suppress the substrate from floating from the thermosensitive adhesive even when exposed to a high-temperature environment. Furthermore, without changing the composition of the first side chain crystalline polymer, the above-mentioned effect can be obtained by a simple method of including a block copolymer in a thermosensitive adhesive.

The content of the block copolymer may be 1 part by weight or more based on 100 parts by weight of the first side chain crystalline polymer. The upper limit of the content of the block copolymer is 50 parts by weight, and preferably 10 parts by weight, but it is not limited thereto.

As the block copolymer, a commercially available product can be used. Examples of commercially available block copolymers include "MODIPER FS710-1" manufactured by Nippon Oil Co., Ltd. and the like.

(Second side chain crystalline polymer)

The temperature-sensitive adhesive of the present embodiment may further contain a second side chain crystalline polymerization having a weight-average molecular weight smaller than that of the first side chain crystalline polymer. Thing. With such a configuration, the following effects can be obtained.

When the temperature-sensitive adhesive is fixed to the adherend and exposed to a high-temperature environment, the temperature-sensitive adhesive becomes soft and has an uneven shape that follows the surface of the adherend. If cooled in this state, a so-called anchor effect appears. As a result, the adhesive force of the thermosensitive adhesive becomes higher than the initial adhesive force, and the peelability is reduced.

It is estimated that the second side chain crystalline polymer having a relatively small weight-average molecular weight functions to reduce the wettability of the temperature-sensitive adhesive to the adherend in a high-temperature environment, and make it difficult for the temperature-sensitive adhesive to follow the surface. The uneven shape on the surface of the adherend. Therefore, if the temperature-sensitive adhesive further contains a second side chain crystalline polymer, the anchoring effect can be suppressed, and the peelability after exposure to a high temperature environment can be improved.

The configuration of the second side chain crystalline polymer is not particularly limited as long as it has a weight average molecular weight smaller than that of the first side chain crystalline polymer. The second side chain crystalline polymer is basically obtained by the same method as the first side chain crystalline polymer. That is, a (meth) acrylic acid ester containing a linear alkyl group having 16 or more carbon atoms, a (meth) acrylic acid ester having an alkyl group having 1 to 6 carbon atoms, and a polar monomer are prepared by a solution polymerization method or the like. And other monomer components obtained by polymerization. The above-mentioned reactive fluorine compound may be contained in a monomer component as needed.

In the polymerization reaction of the second side chain crystalline polymer, in order to make the weight average molecular weight smaller than that of the first side chain crystalline polymer, for example, the polymerization initiation can be increased compared to the polymerization reaction of the first side chain crystalline polymer. The weight average molecular weight is adjusted by the addition amount of an agent, a chain transfer agent, and the like. 2nd side The weight average molecular weight of the chain crystalline polymer is preferably 100,000 or less, more preferably 4,000 to 100,000, still more preferably 4,000 to 40,000, and still more preferably 5,000 to 30,000.

It is preferably 1 to 20 parts by weight, more preferably 1 to 15 parts by weight, still more preferably 1 to 10 parts by weight, and still more preferably 1 to 5 parts by weight relative to 100 parts by weight of the first side chain crystalline polymer. The proportion by weight includes the second side chain crystalline polymer.

Preferred compositions of the second side chain crystalline polymer are 33 to 47% by weight of behenyl acrylate, 32 to 38% by weight of stearyl acrylate, 17 to 23% by weight of methyl acrylate, and 4 by weight of acrylic acid. To 6% by weight. The second side chain crystalline polymer can maximize the ratio of behenyl acrylate in the monomer component.

(Tackifier)

The temperature-sensitive adhesive of the present embodiment may further contain a tackifier. Examples of the tackifier include rosin-based resin, terpene-based resin, hydrocarbon-based resin, epoxy-based resin, polyamide-based resin, phenol-based resin, and ketone-based resin. The tackifier may be used singly or in combination of two or more kinds. Among these, from the viewpoint of compatibility with the side chain crystalline polymer, a rosin-based resin is preferred.

Examples of the rosin-based resin include a rosin derivative. Examples of the rosin derivative include esterification of modified rosin such as gum rosin, wood rosin, tall oil rosin (raw rosin), hydrogenated rosin, heterogeneous rosin, and polymerized rosin with alcohols. Of Rosin Ester compounds; Rosin metal salts of unmodified rosin, modified rosin, various rosin derivatives, etc .; thermal polymerization by addition of phenol to unmodified rosin, modified rosin, various rosin derivatives, etc. with an acid catalyst The obtained rosin phenol resin and the like.

Among rosin derivatives, ester compounds of rosin are preferred. As the ester compound of rosin, a commercially available product can be used. As commercially available ester compounds of rosin, for example, "SUPER ESTER A-100", "SUPER ESTER A-125", "PENSEL D-160" and the like manufactured by Arakawa Chemical Industry Co., Ltd. are mentioned.

The tackifier is preferably contained in an amount of 200 parts by weight or less, more preferably 150 parts by weight or less, and still more preferably 100 parts by weight or less based on 100 parts by weight of the first side chain crystalline polymer. With respect to 100 parts by weight of the first side chain crystalline polymer, if the content of the tackifier is preferably 5 to 40 parts by weight, more preferably 15 to 35 parts by weight, and still more preferably 15 to 25 parts by weight, Peelability tends to improve after exposure to high-temperature environments.

The softening point of the thickener is, for example, about 50 to 250 ° C, and preferably about 90 to 200 ° C. If the softening point is 90 to 140 ° C, preferably 90 to 110 ° C, the peelability after exposure to a high-temperature environment tends to be improved. The softening point is a value measured in accordance with the ring and ball method specified in JIS K 5902.

(Crosslinking agent)

The temperature-sensitive adhesive of the present embodiment may further contain a crosslinking agent. Crosslinker It is used, for example, to crosslink the first side chain crystalline polymers, the second side chain crystalline polymers, or the first side chain crystalline polymer and the second side chain crystalline polymer. Examples of the crosslinking agent include metal chelate compounds, aziridine compounds, isocyanate compounds, and epoxy compounds. Among these, in order to improve heat resistance, a metal chelate compound is preferable.

Examples of the metal chelate compound include a polyvalent metal acetoacetone complex compound, a polyvalent metal acetoacetate complex compound, and the like. Examples of the polyvalent metal include aluminum, nickel, chromium, iron, titanium, zinc, cobalt, manganese, and zirconium. The metal chelate compound may be used alone or in combination of two or more. Among these, an acetoacetone complex or an acetoacetate complex of aluminum is preferred, and tris (acetamidoacetone) aluminum is more preferred.

With respect to 100 parts by weight of the first side chain crystalline polymer, it is preferably contained in a proportion of 0.1 to 20 parts by weight, more preferably in a proportion of 0.5 to 15 parts by weight, and still more preferably in a proportion of 1 to 15 parts by weight.联 剂。 Union agent. When a metal chelate compound is used as the crosslinking agent, it is preferably 0.1 to 20 parts by weight, more preferably 5 to 12 parts by weight relative to 100 parts by weight of the first side chain crystalline polymer. The metal chelate compound is more preferably contained in a proportion of 8 to 12 parts by weight.

After adding a crosslinking agent to a thermosensitive adhesive, a crosslinking reaction can be performed by heating. As the heating conditions, the temperature is about 90 to 110 ° C, and the time is about 1 minute to 20 minutes.

There is no specific use form of the above-mentioned thermosensitive adhesive It does not limit, For example, it can be used as it is, and it can also be used in the form of an adhesive sheet, an adhesive tape, etc. as demonstrated below.

<Thermal adhesive sheet>

The temperature-sensitive adhesive sheet according to the present embodiment includes the above-mentioned temperature-sensitive adhesive, and is in the form of a sheet without a substrate. The thickness of the temperature-sensitive adhesive sheet is preferably 5 to 200 μm, and more preferably 10 to 100 μm.

A release film can be laminated on the surface of the thermosensitive adhesive sheet. Examples of the release film include those coated with a release agent such as polysiloxane on the surface of a film made of polyethylene terephthalate or the like. The thickness of the release film is preferably 5 to 500 μm, and more preferably 25 to 250 μm. When using a thermosensitive adhesive sheet, a release film is peeled.

<Thermal adhesive tape>

The temperature-sensitive adhesive tape according to this embodiment includes a film-shaped substrate and an adhesive layer on at least one area of the substrate. The film shape is not limited to the film shape, and includes a film shape or a sheet shape as long as the effects of the present embodiment are not impaired.

Examples of the constituent material of the substrate include polyethylene, polyethylene terephthalate, polypropylene, polyester, polyamide, polyimide, polycarbonate, and ethylene-vinyl acetate copolymer. , Ethylene-ethyl acrylate copolymer, ethylene-polypropylene copolymer, polyvinyl chloride and other synthetic resins.

The structure of the substrate may be either a single-layer structure or a multilayer structure. The thickness of the substrate is preferably 5 to 500 μm, and more preferably 25 to 250 μm. In order to improve the adhesion to the adhesive layer, the substrate may be subjected to a surface treatment. Examples of the surface treatment include a corona discharge treatment, a plasma treatment, a sandblasting treatment, a chemical etching treatment, and a primer treatment.

The adhesive layer laminated on at least one side of the substrate includes the above-mentioned thermosensitive adhesive. When the adhesive is laminated on at least one side of the base material, for example, a solvent can be added to the thermosensitive adhesive to prepare a coating liquid, and the obtained coating liquid can be coated on one or both sides of the base material with a coater or the like and made dry. Examples of the coater include a knife coater, a roll coater, a calender coater, a notch wheel coater, a gravure coater, and a rod coater.

The thickness of the adhesive layer is preferably 5 to 60 μm, more preferably 10 to 60 μm, and still more preferably 10 to 50 μm.

In the case of the two-layer adhesive layer on the base material, the thickness, composition, and the like of the adhesive layer on one side and the adhesive layer on the other side may be the same or different. In addition, as long as the adhesive layer on one side is composed of the above-mentioned thermosensitive adhesive, the adhesive layer on the other side is not particularly limited. The adhesive layer on the other surface may be made of, for example, a pressure-sensitive adhesive. Examples of the pressure-sensitive adhesive include natural rubber adhesives, synthetic rubber adhesives, styrene-butadiene rubber emulsion adhesives, and acrylic adhesives.

Can release the film on the surface area of the thermosensitive adhesive tape. Examples of the release film are the same as those exemplified in the above-mentioned thermosensitive adhesive sheet. The release film is peeled off during use of the thermosensitive adhesive tape.

Hereinafter, synthesis examples and examples will be described in detail. The present invention is not limited to the following Synthesis Examples and Examples.

(Synthesis example 1: first side chain crystalline polymer)

First, the monomers shown in Table 1 were added to the reaction vessel at the ratios shown in Table 1. The monomers shown in Table 1 are as follows.

C22A: behenyl acrylate

C18A: stearyl acrylate

C1A: methyl acrylate

AA: Acrylic

V3F: Reactive fluorine compound "Viscoat 3F" manufactured by Osaka Organic Chemical Industry Co., Ltd. as 2,2,2-trifluoroethyl acrylate represented by the above formula (Ia)

Then, 200 parts by weight of the solvent was added to the reaction container with respect to 100 parts by weight of the monomer mixture. As the solvent, a mixed solvent of ethyl acetate: toluene = 8: 2 (weight ratio) was used. Furthermore, "Peroyl OPP" made by Nippon Oil Co., Ltd. as a polymerization initiator was added to the reaction container at a ratio of 0.3 parts by weight, and the monomers were copolymerized at 55 ° C for 4 hours to obtain the first side. Chain crystalline polymer. The obtained first side chain crystalline polymer had a weight average molecular weight of 500,000 and a melting point of 45 ° C. The weight average molecular weight is a value obtained by converting the measured value obtained by the GPC measurement into a polystyrene conversion. The melting point is a value measured under a measurement condition of 10 ° C / minute using DSC.

(Synthesis Example 2: Second side chain crystalline polymer)

First, the monomers shown in Table 1 were added to the reaction vessel at the ratios shown in Table 1. Then, 100 parts by weight of the solvent was added to the reaction container with respect to 100 parts by weight of the monomer mixture. As the solvent, toluene was used. Further, after adding "Perhexyl PV" manufactured by Nippon Oil Corporation as a polymerization initiator at a ratio of 1.0 part by weight and adding dodecyl mercaptan as a chain transfer agent at a ratio of 6.0 parts by weight, Stir at 60 ° C for 2 hours. Then, these monomers were further stirred at the reflux temperature for 3 hours, and these monomers were copolymerized to obtain a second side chain crystalline polymer. The weight average molecular weight of the obtained 2nd side chain crystalline polymer was 8000, and melting | fusing point was 50 degreeC.

[Examples 1 to 14 and Comparative Examples 1 to 2] <Production of Thermosensitive Adhesive Sheet>

First, the first side chain crystalline polymerization obtained in Synthesis Example 1 100 parts by weight of the product was mixed with the block copolymer and the second side chain crystalline polymer obtained in Synthesis Example 2 at the ratio shown in Table 2. The block copolymer used is as follows.

Block copolymer: "MODIPER FS710-1" manufactured by Nippon Oil Co., Ltd.

Next, with respect to 100 parts by weight of the first side chain crystalline polymer, the tackifier and the cross-linking agent were further mixed at a ratio of 20 parts by weight to obtain a thermosensitive adhesive. The tackifiers and crosslinkers used are as follows.

Tackifier: Rosin ester compound "SUPER ESTER A-100" manufactured by Arakawa Chemical Industries, Ltd. with a softening point of 95 to 105 ° C

Crosslinking agent: tris (acetamidine) aluminum manufactured by Kawaken Fine Chemicals Co., Ltd. as a metal chelate compound

Then, the obtained thermosensitive adhesive was adjusted with ethyl acetate so that solid content concentration might become 30 weight%, and the coating liquid was obtained. Then, the obtained coating liquid was coated on a release film, and a crosslinking reaction was performed under the conditions of 100 ° C. × 10 minutes to obtain a 25 μm-thick thermosensitive adhesive sheet. In addition, the release film is a polyethylene terephthalate film having a thickness of 50 μm in which polysiloxane is coated on the surface.

<Evaluation>

About each temperature-sensitive adhesive sheet obtained in Examples 1 to 14 and Comparative Examples 1 to 2, the glass-glass peeling strength was evaluated. Evaluation methods are shown below, and the results are shown in Table 2.

(Evaluation method of glass-glass peeling strength)

As shown in FIG. 1, first, the slide glass 1 a is fixed to the base 2 among two slide glasses 1 a and 1 b (26 mm in width, 76 mm in length, and 1.1 mm in thickness). The fixing is performed by fixing both ends of the slide glass 1 a to the base 2 with the fixture 3.

Next, the temperature-sensitive adhesive sheet 4 (2 cm × 2 cm) was adhered to the surface of the slide glass 1a at an ambient temperature of 50 ° C., and the temperature-sensitive adhesive sheet 4 was degassed at 200 ° C. × 10 minutes. deal with. Then, the ambient temperature was lowered to 50 ° C., and a further slide glass 1 b was fixed to the slide glass 1 a via a thermosensitive adhesive sheet 4 in a cross shape at the ambient temperature.

After heating under conditions of 230 ° C. for 30 minutes or 250 ° C. for 60 minutes, the ambient temperature was lowered to 5 ° C., and the mixture was allowed to stand at the ambient temperature for 5 minutes. Then, the glass slide 1b was lifted in the direction of arrow A at a speed of 300 mm / min at an ambient temperature of 5 ° C, and the peel strength when the glass slide 1b was peeled from the glass slide 1a was measured.

As apparent from Table 2, Examples 1 to 14 containing the block copolymer were excellent in peelability after exposure to a high-temperature environment.

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Claims (9)

A temperature-sensitive adhesive containing a first side-chain crystalline polymer, and the adhesive force decreases at a temperature lower than the melting point of the first side-chain crystalline polymer, wherein the temperature-sensitive adhesive further contains A block copolymer containing silicone and acrylic resin. The temperature-sensitive adhesive according to item 1 of the scope of patent application, wherein the content of the block copolymer is 1 part by weight or more based on 100 parts by weight of the first side chain crystalline polymer. The temperature-sensitive adhesive according to item 1 of the scope of patent application, further comprising a second side chain crystalline polymer having a smaller weight average molecular weight than the first side chain crystalline polymer. The temperature-sensitive adhesive according to item 3 of the scope of patent application, wherein the content of the second side chain crystalline polymer is 1 to 20 parts by weight based on 100 parts by weight of the first side chain crystalline polymer. The temperature-sensitive adhesive according to item 1 of the scope of patent application, wherein the glass-glass peel strength at an ambient temperature of 5 ° C after 30 minutes of exposure to an ambient temperature of 230 ° C is 10 N / 400 mm ² or less. The temperature-sensitive adhesive according to item 1 of the scope of patent application, wherein the glass-glass peel strength at an ambient temperature of 5 ° C. after being exposed to an ambient temperature of 250 ° C. for 60 minutes is 15 N / 400 mm ² or less. The temperature-sensitive adhesive according to item 1 of the scope of patent application, which is used for temporary fixing of a substrate in a manufacturing step of a touch sensor or an organic EL element. The invention relates to a temperature-sensitive adhesive sheet, which comprises the temperature-sensitive adhesive described in item 1 of the patent application scope. A temperature-sensitive adhesive tape comprising: a film-shaped substrate; and an adhesive layer laminated on at least one side of the substrate and containing the temperature-sensitive adhesive described in Item 1 of the scope of patent application.