WO2015152006A1 - Side chain crystalline polymer, thermosensitive adhesive agent, thermosensitive adhesive sheet, and thermosensitive adhesive tape - Google Patents

Abstract

A side chain crystalline polymer according to the present invention comprises a crystalline macromonomer and a graft copolymer of a non-crystalline monomer. A thermosensitive adhesive agent according to the present invention contains an acrylic pressure-sensitive bonding agent and the side chain crystalline polymer and has decreased adhesive force at temperatures at or above the melting point of the side chain crystalline polymer. A thermosensitive adhesive sheet according to the present invention comprises the thermosensitive adhesive agent. A thermosensitive adhesive tape according to the present invention is provided with a substrate film and an adhesive agent layer that comprises the thermosensitive adhesive agent and that is laminated on at least one surface of the substrate film.

Description

Side chain crystalline polymer, thermosensitive adhesive, thermosensitive adhesive sheet, and thermosensitive adhesive tape

The present invention relates to a side chain crystalline polymer, a thermosensitive adhesive, a thermosensitive adhesive sheet, and a thermosensitive adhesive tape.

The temperature-sensitive adhesive contains a pressure-sensitive adhesive and a side chain crystalline polymer, and the adhesive strength decreases at a temperature equal to or higher than the melting point of the side chain crystalline polymer. A temperature-sensitive adhesive tape, which is one usage form of a temperature-sensitive adhesive, is used for temporarily fixing parts in the fields of electronic parts, semiconductor wafers, liquid crystals, and the like (see, for example, Patent Document 1). The conventional side chain crystalline polymer as described in Patent Document 1 is composed of a random copolymer. As the temperature-sensitive adhesive, those having excellent adhesive properties are desirable.

JP 2000-355684 A

An object of the present invention is to provide a side-chain crystalline polymer that can be used as a temperature-sensitive adhesive having excellent adhesive properties, a temperature-sensitive adhesive, a temperature-sensitive adhesive sheet, and a temperature-sensitive adhesive tape containing the side-chain crystalline polymer. That is.

The side chain crystalline polymer of the present invention comprises a graft copolymer of a crystalline macromonomer and an amorphous monomer.
The temperature-sensitive pressure-sensitive adhesive of the present invention contains an acrylic pressure-sensitive adhesive and the side chain crystalline polymer, and the adhesive force is lowered at a temperature equal to or higher than the melting point of the side chain crystalline polymer.
The temperature-sensitive adhesive sheet of the present invention comprises the temperature-sensitive adhesive.
The temperature sensitive adhesive tape of this invention is equipped with a base film and the adhesive layer which consists of the said temperature sensitive adhesive laminated | stacked on the at least single side | surface of the said base film.

According to the present invention, there is an effect that the adhesive property is excellent.

[Side-chain crystalline polymer]
Hereinafter, the side chain crystalline polymer according to an embodiment of the present invention will be described. The side chain crystalline polymer of this embodiment is, for example, a graft copolymer represented by the following general formula (I).

[Wherein, R ₁ represents a linear alkyl group having 16 or more carbon atoms. R ₂ represents a hydrogen atom or a methyl group. R ₃ and R ₄ are the same or different groups, and each represents an alkyl group having 1 to 12 carbon atoms. n represents an integer of 2 to 80. x is an integer of 10 to 90, and y and z are integers such that y + z = 10 to 90. Note that x + y + z = 100. ]

The side chain crystalline polymer represented by the general formula (I) described above is a graft copolymer of a crystalline macromonomer represented by the following general formula (II) and an amorphous monomer.

[Wherein, R _1, R ₂ and n are the same as R _1, R ₂ and n in the general formula (I). ]

In this embodiment, the crystalline macromonomer represented by the general formula (II) constitutes a branch part of the graft copolymer, and is a site that functions as a crystalline component in the graft copolymer. The non-crystalline monomer is a site that constitutes the trunk (main chain) of the graft copolymer and functions as a component compatible with the acrylic pressure-sensitive adhesive described later. When the side-chain crystalline polymer of this embodiment composed of a graft copolymer of such a crystalline macromonomer and an amorphous monomer is contained in an acrylic pressure-sensitive adhesive to form a temperature-sensitive adhesive, adhesive physical properties An excellent effect can be obtained. The reason for this is presumed as follows.

Since the conventional side chain crystalline polymer described above is composed of a random copolymer, the crystalline component and the compatible component are also randomly present in the copolymer, and each component is difficult to function sufficiently. It is inferred that In the side chain crystalline polymer of this embodiment, since the crystalline component and the compatible component are separately present in the copolymer, the function of each component is fully exhibited, and as a result, the temperature-sensitive adhesive It is presumed that when it is used as an agent, it exhibits an excellent effect on the adhesive physical properties. Specifically, when the side-chain crystalline polymer of this embodiment is included in an acrylic pressure-sensitive adhesive to form a temperature-sensitive adhesive, the initial adhesive force is sufficient at a temperature below the melting point of the side-chain crystalline polymer. The adhesive strength can be sufficiently reduced at a temperature equal to or higher than the melting point. Hereinafter, the configuration of the side chain crystalline polymer of the present embodiment will be specifically described.

The side chain crystalline polymer of the present embodiment has a melting point. The side chain crystalline polymer of this embodiment is crystallized at a temperature below the melting point, and exhibits phase transition at a temperature above the melting point to exhibit fluidity. That is, the side chain crystalline polymer of the present embodiment has temperature sensitivity that reversibly causes a crystalline state and a fluid state in response to a temperature change.

The melting point is a temperature at which a specific portion of the polymer that was initially aligned in an ordered arrangement becomes disordered by an equilibrium process, and is measured at 10 ° C./min by a differential thermal scanning calorimeter (DSC). It shall mean the value obtained by measurement.

The melting point of the side chain crystalline polymer of the present embodiment is not particularly limited, and is preferably higher than room temperature (23 ° C.), for example. The melting point can be adjusted by changing the composition of the side chain crystalline polymer.

The weight average molecular weight of the side chain crystalline polymer of this embodiment is preferably larger than the weight average molecular weight of the crystalline macromonomer and 20,000 or less. Although the lower limit of a weight average molecular weight is not specifically limited as long as the effect of this embodiment is acquired, It is preferable that it is 500 or more. The weight average molecular weight is a value obtained by measuring the side chain crystalline polymer by gel permeation chromatography (GPC) and converting the obtained measurement value to polystyrene.

In addition, as long as the structure of the side chain crystalline polymer of this embodiment is composed of a graft copolymer of a crystalline macromonomer and an amorphous monomer, the structure of the graft polymer represented by the general formula (I) described above is used. It is not limited. Moreover, the side chain crystalline polymer of this embodiment can also be used independently, without using it in combination with the acrylic pressure-sensitive adhesive mentioned later. When the side chain crystalline polymer of this embodiment is used alone, it is possible to provide a temperature-sensitive adhesive whose adhesive strength is reduced at a temperature lower than the melting point of the side chain crystalline polymer.

(Crystalline macromonomer)
The crystalline macromonomer means a high molecular weight monomer having crystallinity and having a polymerizable double bond that can be polymerized with an amorphous monomer at one end. The crystalline macromonomer in the present embodiment is a macromonomer represented by the above-described general formula (II) having a (meth) acrylic ester group at one end. The carbon-carbon unsaturated bond in this (meth) acrylic acid ester group is a polymerizable double bond copolymerizable with an amorphous monomer. In the general formula (II), R ₁ representing a linear alkyl group having 16 or more carbon atoms functions as a crystalline site.

The weight average molecular weight of the crystalline macromonomer in this embodiment is preferably 10,000 or less. Although the lower limit of a weight average molecular weight is not specifically limited as long as the effect of this embodiment is acquired, It is preferable that it is 400 or more. The weight average molecular weight is a value obtained by measuring a crystalline macromonomer by GPC and converting the obtained measurement value into polystyrene.

The configuration of the crystalline macromonomer of this embodiment is a high molecular weight monomer having a plurality of predetermined linear alkyl groups and having a polymerizable double bond capable of being polymerized with an amorphous monomer at one end. As long as it is not limited to the structure represented by the general formula (II) described above.

(Non-crystalline monomer)
Examples of the amorphous monomer in the present embodiment include (meth) acrylate having a C 1-12 alkyl group, a polar monomer, a reactive polysiloxane compound, vinyl acetate, styrene, and the like. In other words, the non-crystalline monomer in the present embodiment is at least one selected from (meth) acrylates having a C 1-12 alkyl group, polar monomers, reactive polysiloxane compounds, vinyl acetate and styrene. Is preferred. In addition, (meth) acrylate shall mean a methacrylate or an acrylate.

Examples of the (meth) acrylate having an alkyl group having 1 to 12 carbon atoms include methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, hexyl (meth) acrylate, and the like. You may use these 1 type or in mixture of 2 or more types. Of these examples, those having high cohesive strength are desirable in order to suppress a decrease in adhesive strength when the temperature rises. Specific examples include methyl acrylate. Therefore, it is preferable that the non-crystalline monomer contains at least methyl acrylate.

Examples of polar monomers include ethylene unsaturated monomers having a carboxyl group such as (meth) acrylic acid, crotonic acid, itaconic acid, maleic acid, fumaric acid; 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl ( Examples thereof include ethylenically unsaturated monomers having a hydroxyl group such as (meth) acrylate and 2-hydroxyhexyl (meth) acrylate. You may use these 1 type or in mixture of 2 or more types.

The reactive polysiloxane compound means a polysiloxane compound having a reactive functional group and having a siloxane bond in the main chain. Examples of the functional group showing reactivity include a group having an ethylenically unsaturated double bond such as vinyl group, allyl group, (meth) acryl group, (meth) acryloyl group and (meth) acryloxy group; epoxy group (glycidyl) Group and an epoxycycloalkyl group), mercapto group, carbinol group, carboxyl group, silanol group, phenol group, amino group, hydroxyl group and the like.

These functional groups may be introduced into the side chain of the main chain, or may be introduced into both ends or one end of the main chain. That is, there are four types of reactive polysiloxane compounds, so-called side chain type, double-ended type, single-ended type, and double-ended side chain type, depending on the bonding position of the functional group to be introduced. One end type, that is, a one end reactive polysiloxane compound is preferable.

Specific examples of the one-terminal reactive polysiloxane compound include a modified polydimethylsiloxane compound represented by the following general formula (III).

[Wherein R ₅ represents an alkyl group. R ₆ represents a group: CH ₂ ═CHCOOR ⁷ — or CH ₂ ═C (CH ₃ ) COOR ⁷ — (wherein R ⁷ represents an alkylene group). r represents an integer of 5 to 200. ]

In general formula (III), examples of the alkyl group represented by R ₅ include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, an s-butyl group, a t-butyl group, and pentyl. And straight-chain or branched alkyl groups having 1 to 6 carbon atoms such as a group, isopentyl group, neopentyl group, and hexyl group.

Examples of the alkylene group represented by R ⁷ include straight chain having 1 to 6 carbon atoms such as methylene group, ethylene group, trimethylene group, methylethylene group, propylene group, tetramethylene group, pentamethylene group, hexamethylene group, and the like. Examples include branched alkylene groups.

Specific examples of the modified polydimethylsiloxane compound represented by the general formula (III) include compounds represented by the following general formula (IIIa).

[Wherein R ₅ , R ⁷ and r are the same as those in formula (III). ]

As the modified polydimethylsiloxane compound, a commercially available product can be used. Specific examples thereof include, for example, single-end reactive silicone oils “X-22-2404” and “X-24” manufactured by Shin-Etsu Chemical Co., Ltd. -8201 "," X-22-174DX "," X-22-2426 "and the like.

[Method for producing crystalline macromonomer]
Next, regarding the method for producing a crystalline macromonomer according to an embodiment of the present invention, the crystalline macromonomer represented by the general formula (II) described above (hereinafter referred to as “crystalline macromonomer (II)”) This will be described in detail by taking as an example the case of manufacturing.

In this embodiment, as shown in the following reaction formula, first, in the presence of the chain transfer agent (V) having a hydroxyl group, the crystalline monomer (IV) and, if necessary, other monomers are radically polymerized, and one end is subjected to radical polymerization. A prepolymer (VI) having hydroxyl groups is obtained. Next, the functionalizing agent (VII) having a polymerizable double bond is reacted with the hydroxyl group of the prepolymer (VI) to obtain a crystalline macromonomer (II).

[Wherein, R ₁ and n are the same as those in formula (I). ]

[Wherein R ₁ , R ₂ and n are the same as those in formula (I). ]

Examples of the crystalline monomer (IV) include (meth) acrylate having a linear alkyl group having 16 or more carbon atoms, preferably 16 to 50 carbon atoms, more preferably 16 to 22 carbon atoms. Examples of the (meth) acrylate having a linear alkyl group having 16 or more carbon atoms include cetyl (meth) acrylate, stearyl (meth) acrylate, eicosyl (meth) acrylate, and behenyl (meth) acrylate. You may use these 1 type or in mixture of 2 or more types. The linear alkyl group having 16 or more carbon atoms in the (meth) acrylate described above corresponds to R ₁ .

Other monomers are not particularly limited as long as they are copolymerizable with the crystalline monomer (IV), and are the same as those exemplified as the amorphous monomer from the viewpoint of compatibility with the amorphous monomer. Is preferred. You may use these 1 type or in mixture of 2 or more types.

The polymerization ratio of the crystalline monomer (IV) and other monomers is not particularly limited, and is preferably 90 to 100 parts by weight of the crystalline monomer (IV) and 0 to 10 parts by weight of the other monomers.

As the chain transfer agent (V) in this embodiment, mercaptoethanol is used, but is not limited thereto. Any chain transfer agent (V) may be used as long as it can introduce a hydroxyl group into the prepolymer (VI). Thiol compounds having a hydroxyl group such as mercaptocyclohexanol and mercaptophenol can be used. The amount of chain transfer agent (V) to be used is usually 0.1 to 25 parts by weight, preferably 3 to 15 parts by weight, based on 100 parts by weight of the total amount of the crystalline monomer (IV) and other monomers.

The polymerization reaction of the prepolymer (VI) may be performed without a solvent or in a polymerization solvent. Examples of the polymerization solvent include aromatic hydrocarbons such as toluene and xylene; aliphatic esters such as ethyl acetate and butyl acetate; alicyclic hydrocarbons such as cyclohexane; and aliphatic hydrocarbons such as hexane and pentane. Etc. You may use these 1 type or in mixture of 2 or more types. What is necessary is just to determine the usage-amount of a polymerization solvent suitably.

The polymerization temperature of the prepolymer (VI) is usually 20 to 200 ° C, preferably 40 to 120 ° C. The polymerization time is usually 1 to 24 hours, preferably 1 to 7 hours. The reaction pressure is not particularly limited, and may be normal pressure (atmospheric pressure), reduced pressure, or increased pressure. The polymerization reaction is desirably performed in an inert gas atmosphere such as nitrogen gas.

In the polymerization reaction of the prepolymer (VI), a polymerization initiator may be used. Examples of the polymerization initiator include azo polymer polymerization initiators such as 2,2′-azobisisobutyronitrile and 2,2′-azobis (2,4-dimethylvaleronitrile); bezoyl peroxide, dimethyl ethyl ketone Examples thereof include organic peroxides such as peroxide and lauryl peroxide. As the polymerization initiator, commercially available products can be used. Specifically, as the azo polymer polymerization initiator, both “ABN-R” and “ABN” manufactured by Nippon Hydrazine Kogyo Co., Ltd. can be used. -V "," ABN-E "and the like, and examples of the organic peroxide include" Pertetra A "," Perhexyl ND ", and" Perbutyl ND "manufactured by NOF Corporation. You may use these 1 type or in mixture of 2 or more types. What is necessary is just to determine the usage-amount of a polymerization initiator suitably.

The functionalizing agent (VII) of this embodiment is di (meth) acrylic anhydride. Therefore, the crystalline macromonomer (II) of this embodiment is obtained by converting the crystalline monomer (IV) containing (meth) acrylate having a linear alkyl group having at least 16 carbon atoms into a chain transfer agent (V) having a hydroxyl group. It is obtained by reacting a prepolymer (VI) having a hydroxyl group at one end with a functionalizing agent (VII), which is a di (meth) acrylic anhydride, obtained by radical polymerization in the presence of And a macromonomer having a linear alkyl group having 16 or more carbon atoms represented by R ₁ in the side chain and having a polymerizable double bond capable of being polymerized with an amorphous monomer at one end.

In addition, as above-mentioned as functional grouping agent (VII) in this embodiment, although di (meth) acrylic acid anhydride is used, it is not limited to this. That is, the functionalizing agent (VII) reacts with the hydroxyl group of the prepolymer (VI) to form a crystalline macromonomer (II) having a polymerizable double bond polymerizable with an amorphous monomer at one end. If it can do, it will not be limited to acid anhydrides, such as di (meth) acrylic acid anhydride.

The amount of the functionalizing agent (VII) used is not particularly limited, but is preferably larger than the amount of chain transfer agent (V) used, and is 1 in molar ratio to the amount of chain transfer agent (V) used. More preferably, it is 0.05 times to 1.1 times. In order to obtain the side chain crystalline polymer efficiently, the remaining functionalizing agent (VII) is preferably removed by reacting with water or the like.

The reaction using the prepolymer (VI) as the crystalline macromonomer (II) can be carried out in a solvent. As a solvent, the same thing as what was illustrated as a polymerization solvent of prepolymer (VI) is mentioned, for example. What is necessary is just to determine the usage-amount of a polymerization solvent suitably.

The reaction temperature in which the prepolymer (VI) is the crystalline macromonomer (II) is usually 50 to 150 ° C., preferably 50 to 130 ° C. The reaction time is usually 10 minutes to 8 hours, preferably 30 minutes to 4 hours. The reaction pressure is not particularly limited, and may be normal pressure (atmospheric pressure), reduced pressure, or increased pressure.

In the reaction using the prepolymer (VI) as the crystalline macromonomer (II), a polymerization inhibitor may be used. Moreover, it may replace with use of a polymerization inhibitor and may bubble mixed air, and may use these together.
In addition, the manufacturing method of crystalline macromonomer (II) is not limited to the reaction formula mentioned above as long as crystalline macromonomer (II) is obtained.

[Method for producing side chain crystalline polymer]
Next, regarding the method for producing a side chain crystalline polymer according to an embodiment of the present invention, the side chain crystalline polymer represented by the general formula (I) described above (hereinafter referred to as “side chain crystalline polymer (I)”) This will be described in detail with reference to an example of manufacturing.

In this embodiment, as shown in the following reaction formula, the side chain crystalline polymer (I) is produced by a macromonomer method in which the above-described crystalline macromonomer (II) is copolymerized with the amorphous monomers (VIII, IX). Get. According to this macromonomer method, a crystalline macromonomer (II) is copolymerized via a polymerizable double bond in a copolymer (a trunk part) of an amorphous monomer (VIII, IX), thereby producing a crystalline macromonomer. The residue of monomer (II) forms a branch. As a result, the side chain crystalline polymer (I) which is a graft copolymer can be obtained efficiently. In addition, it is easy to homogenize the polymer forming the branch part, and it is easy to control the molecular weight of the branch part. The amorphous monomer (VIII, IX) of this embodiment is a (meth) acrylate having an alkyl group having 1 to 12 carbon atoms, but is not limited thereto.

[Wherein, R ₁ , R ₂ , R ₃ , R ₄ , x, y, z and n are the same as those in the general formula (I). ]

The polymerization ratio of the crystalline macromonomer (II) is preferably 10 to 90 parts by weight, and more preferably 20 to 80 parts by weight. The polymerization ratio of the amorphous monomer (VIII, IX) is preferably 10 to 90 parts by weight, more preferably 20 to 80 parts by weight.

The polymerization reaction of the graft copolymer may be performed without a solvent or in a polymerization solvent. It does not specifically limit as a polymerization solvent, The same thing as what was illustrated as a polymerization solvent of prepolymer (VI) is mentioned. What is necessary is just to determine the usage-amount of a polymerization solvent suitably.

In the polymerization reaction of the graft copolymer, a chain transfer agent may be used to adjust the molecular weight distribution of the graft copolymer. The chain transfer agent is not particularly limited, and examples thereof include sulfur-containing compounds such as dodecanethiol, thioglycolic acid, thioacetic acid, and mercaptoethanol; phosphorous acid compounds such as phosphorous acid and sodium phosphite; hypophosphorous acid And hypophosphite compounds such as sodium hypophosphite; alcohols such as methyl alcohol, ethyl alcohol, isopropyl alcohol, and n-butyl alcohol. You may use these 1 type or in mixture of 2 or more types. What is necessary is just to determine the usage-amount of a chain transfer agent suitably.

The polymerization temperature of the graft copolymer is usually 20 to 200 ° C, preferably 40 to 120 ° C. The polymerization time is usually 1 to 24 hours, preferably 1 to 7 hours. The reaction pressure is not particularly limited, and may be normal pressure (atmospheric pressure), reduced pressure, or increased pressure. The polymerization reaction is desirably performed in an inert gas atmosphere such as nitrogen gas.

In the polymerization reaction of the graft copolymer, a polymerization initiator may be used. It does not specifically limit as a polymerization initiator, The same thing as what was illustrated as a polymerization initiator of prepolymer (VI) is mentioned. What is necessary is just to determine the usage-amount of a polymerization initiator suitably.
In addition, the manufacturing method of side chain crystalline polymer (I) is not limited to the reaction formula mentioned above as long as side chain crystalline polymer (I) is obtained.

[Temperature sensitive adhesive]
The temperature-sensitive adhesive according to one embodiment of the present invention contains an acrylic pressure-sensitive adhesive and the above-described side chain crystalline polymer. A temperature-sensitive adhesive means an adhesive whose adhesive force changes in response to a temperature change.

The temperature-sensitive adhesive of the present embodiment is a ratio at which the adhesive strength decreases when the side-chain crystalline polymer exhibits fluidity at a temperature higher than a preset switching temperature, that is, a temperature higher than the melting point of the side-chain crystalline polymer. And contains a side chain crystalline polymer. Therefore, if the temperature-sensitive adhesive of this embodiment is heated to a temperature equal to or higher than the melting point of the side-chain crystalline polymer, the side-chain crystalline polymer exhibits fluidity, thereby preventing the pressure-sensitive adhesive from sticking. Thereby, since adhesive force falls, a to-be-adhered member can be removed easily.

The side chain crystalline polymer is preferably blended at a ratio of 0.1 to 50 parts by weight with respect to 100 parts by weight of the acrylic pressure-sensitive adhesive, but is not limited thereto. That is, the side chain crystalline polymer is not limited to the exemplified composition as long as the initial adhesive strength of the temperature-sensitive adhesive is higher than 0 N / 25 mm, and can be blended in a desired ratio.

The temperature-sensitive adhesive of this embodiment has high transparency because it contains an acrylic pressure-sensitive adhesive that is compatible with the above-described side chain crystalline polymer trunk. Examples of the monomer constituting the acrylic pressure-sensitive adhesive include alkyl groups having 1 to 12 carbon atoms such as ethylhexyl (meth) acrylate, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, and the like. (Meth) acrylate having a hydroxyalkyl group such as hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxyhexyl (meth) acrylate, and the like. These exemplified monomers can be used alone or in combination of two or more.

The weight average molecular weight of the acrylic pressure-sensitive adhesive is preferably 250,000 to 1,500,000. When the weight average molecular weight is too small, when removing the adherend member, the adhesive may remain on the adherend member, so-called adhesive residue may increase. On the other hand, if the weight average molecular weight is too large, the cohesive force of the pressure-sensitive adhesive becomes too high and the pressure-sensitive adhesive force may be lowered. The weight average molecular weight is a value obtained by measuring an acrylic pressure-sensitive adhesive with GPC and converting the obtained measurement value into polystyrene.

The method for producing the temperature sensitive adhesive is not particularly limited. To give a specific example, first, a side chain crystalline polymer is adjusted with a solvent to obtain a copolymer solution. Next, the monomers constituting the acrylic pressure-sensitive adhesive are polymerized to obtain an acrylic pressure-sensitive adhesive. Then, the copolymer solution and the pressure-sensitive adhesive are mixed to obtain a pressure-sensitive adhesive solution, and the obtained pressure-sensitive adhesive solution may be dried.

The polymerization method of the monomer constituting the acrylic pressure-sensitive adhesive is not particularly limited, and for example, a solution polymerization method, a bulk polymerization method, a suspension polymerization method, an emulsion polymerization method, and the like can be employed. For example, when the solution polymerization method is employed, the monomer can be polymerized by mixing the monomer constituting the acrylic pressure-sensitive adhesive with a solvent and stirring at about 40 to 90 ° C. for about 2 to 10 hours. A well-known thing can be used as a solvent.

[Temperature sensitive adhesive sheet]
The temperature-sensitive adhesive of the present embodiment described above can be used as, for example, a substrate-less temperature-sensitive adhesive sheet. The sheet is not limited to a sheet shape, and is a concept including a sheet shape or a film shape as long as the effects of the present embodiment are not impaired. The thickness of the temperature-sensitive adhesive sheet is 1 to 500 μm, preferably 5 to 300 μm. A release film is preferably laminated on the surface of the temperature-sensitive adhesive sheet. Examples of the release film include those obtained by applying a release agent such as silicone to the surface of a film made of polyethylene terephthalate or the like.

[Temperature sensitive adhesive tape]
The temperature-sensitive adhesive of this embodiment can be used in the form of a tape, for example, in addition to the above-described baseless form. The temperature-sensitive adhesive tape which concerns on one Embodiment of this invention is equipped with the base film and the adhesive layer which consists of the temperature-sensitive adhesive mentioned above laminated | stacked on the at least single side | surface of this base film. That is, the structure of the temperature-sensitive adhesive tape of this embodiment is a two-layer structure comprising a base film and an adhesive layer laminated on one side of the base film; or the base film and the base film It has a three-layer structure composed of pressure-sensitive adhesive layers laminated on both sides.

Examples of the base film include synthetic resin films such as polyethylene, polyethylene terephthalate, polypropylene, polyester, polyamide, polyimide, polycarbonate, ethylene vinyl acetate copolymer, ethylene ethyl acrylate copolymer, ethylene polypropylene copolymer, and polyvinyl chloride. Is mentioned.

The base film may be composed of a single layer or a multilayer, and the thickness is usually about 5 to 500 μm. The surface of the base film may be subjected to surface treatment such as corona discharge treatment, plasma treatment, blast treatment, chemical etching treatment, primer treatment, etc. in order to improve adhesion to the pressure-sensitive adhesive layer.

The thickness of the pressure-sensitive adhesive layer is 1 to 500 μm, preferably 5 to 300 μm.

When the temperature-sensitive adhesive tape of the present embodiment has a three-layer configuration, the thickness and composition of the one-sided adhesive layer and the other-sided adhesive layer may be the same or different. Also good.

In addition, when the temperature-sensitive adhesive tape of the present embodiment has a three-layer configuration, the other-side adhesive layer is not particularly limited as long as the one-sided adhesive layer is made of the above-described temperature-sensitive adhesive. Therefore, the pressure-sensitive adhesive layer on the other side can be constituted by, for example, a pressure-sensitive adhesive layer made of a pressure-sensitive adhesive. The pressure-sensitive adhesive is a polymer having tackiness, and examples thereof include natural rubber adhesives, synthetic rubber adhesives, styrene / butadiene latex base adhesives, and acrylic adhesives.

As a method for producing the temperature-sensitive adhesive tape of the present embodiment, for example, a coating solution obtained by adding the above-described temperature-sensitive adhesive to a solvent may be applied to the surface of the substrate film and dried. The coating can be generally performed with a knife coater, a roll coater, a calendar coater, a comma coater or the like. Further, depending on the coating thickness and the viscosity of the coating solution, a gravure coater, a rod coater or the like can be used. A release film is preferably laminated on the surface of the pressure-sensitive adhesive layer, similarly to the temperature-sensitive pressure-sensitive adhesive sheet.

Various additives such as a crosslinking agent, a tackifier, a plasticizer, an anti-aging agent, and an ultraviolet absorber are added to the above-described temperature-sensitive adhesive, temperature-sensitive adhesive sheet, and temperature-sensitive adhesive tape. Can do. Moreover, as a use of a thermosensitive adhesive, a thermosensitive adhesive sheet, and a thermosensitive adhesive tape, it can be used conveniently for the field | area which requires easy peelability. Examples of adhesive members for thermosensitive adhesives, thermosensitive adhesive sheets and thermosensitive adhesive tapes include, for example, touch panel bodies and liquid crystal covers in liquid crystal touch panels, as well as organic electroluminescence (organic EL), calculators, and personal computers. Examples include, but are not limited to, built-in electronic components, backlights and panel portions in liquid crystal panels.

The preferred embodiments according to the present invention have been described above, but the present invention is not limited to the above-described embodiments, and it goes without saying that the embodiments can be arbitrarily set without departing from the gist of the present invention.

For example, in the above-described embodiment, the case where di (meth) acrylic anhydride is used as the functionalizing agent (VII) has been described as an example. Instead, a (meth) acrylate having an isocyanato group is used as the functional group. It can be used as the agent (VII) ′.

When the functionalizing agent (VII) ′ is used, the crystalline macromonomer represented by the general formula (II) ′ (hereinafter referred to as “crystalline macromonomer (II) ′”) as shown in the following reaction formula: There is.)

[Wherein, R ₁ and n are the same as those in formula (I). R ₈ represents a hydrogen atom or a methyl group. m represents an integer of 1 to 9. ]

Crystalline macromonomer (II) ′ is a crystalline monomer (IV) containing (meth) acrylate having a linear alkyl group having at least 16 carbon atoms in the presence of a chain transfer agent (V) having a hydroxyl group. A side chain obtained by reacting a prepolymer (VI) having a hydroxyl group at one end with a functionalizing agent (VII) ′, which is a (meth) acrylate having an isocyanato group, obtained by radical polymerization. Is a macromonomer having a straight-chain alkyl group having 16 or more carbon atoms represented by R ₁ and having a polymerizable double bond capable of being polymerized with an amorphous monomer at one end.

Examples of the (meth) acrylate having an isocyanato group used as the functionalizing agent (VII) 'include 2-isocyanatoethyl (meth) acrylate. As the (meth) acrylate having an isocyanato group, a commercially available product can be used. Specific examples thereof include “Karenz AOI” and “Karenz MOI” manufactured by Showa Denko K.K.

The amount of the (meth) acrylate having an isocyanato group is preferably 1.0 to 2.0 times in molar ratio to the amount of the chain transfer agent (V) having a hydroxyl group. In other words, the molar ratio of the (meth) acrylate having an isocyanato group to the chain transfer agent (V) having a hydroxyl group ((meth) acrylate having an isocyanato group / chain transfer agent having a hydroxyl group) is 1.0 to It is preferably 2.0. Thereby, the reaction rate of prepolymer (VI) and the (meth) acrylate which has an isocyanato group can be improved. Moreover, when a side chain crystalline polymer is produced using the obtained crystalline macromonomer (II) 'and contained in a temperature-sensitive adhesive, the adhesive physical properties tend to be improved. From the viewpoint of improving the reaction rate between the prepolymer (VI) and the (meth) acrylate having an isocyanato group, the above-described molar ratio ((meth) acrylate having an isocyanato group / chain transfer agent having a hydroxyl group) is 1 More preferably, it is from 2 to 2.0, and even more preferably from 1.5 to 2.0.

In order to increase the reaction rate between the prepolymer (VI) and the (meth) acrylate having an isocyanato group, a catalyst may be used. The amount of the catalyst used is preferably 10 parts by weight or less with respect to 100 parts by weight in total of the prepolymer (VI) and the (meth) acrylate having an isocyanato group. Thereby, the above-mentioned reaction rate can be increased while maintaining the pot life (pot life) of the coating liquid.

Examples of the catalyst include organotin compounds such as dibutyltin dilaurate, organometallic compounds such as bismuth catalyst and potassium catalyst. Moreover, a commercially available catalyst can be used, and specific examples include, for example, “Pucat 25”, “Pucat B7”, “Pucat 15G” manufactured by Nippon Chemical Industry Co., Ltd.

Hereinafter, the present invention will be described in detail with reference to synthesis examples and examples, but the present invention is not limited to the following synthesis examples and examples. In the following description, “part” means part by weight.

[Synthesis Example 1: Pressure-sensitive adhesive]
52 parts of ethylhexyl acrylate, 40 parts of methyl acrylate, 8 parts of hydroxyethyl acrylate, and 0.2 part of “Perbutyl ND” manufactured by NOF Corporation as a polymerization initiator are added to 200 parts of toluene and stirred at 60 ° C. for 5 hours. These monomers were polymerized. The weight average molecular weight of the obtained copolymer was 460,000.

[Synthesis Example 2: Side chain crystalline polymer]
(Prepolymer)
First, 39.2 parts of behenyl acrylate as a crystalline monomer, 35.3 parts of stearyl acrylate, 3.9 parts of acrylic acid as another monomer, 4.7 parts of mercaptoethanol as a chain transfer agent, and 122 parts of toluene as a polymerization solvent The solution was heated to 90 ° C. in an oil bath and bubbled with nitrogen for 30 minutes. Next, 0.78 part of azobisisobutyronitrile (AIBN) as a polymerization initiator was dissolved in 30 parts of toluene and charged into a beaker. The mixture was stirred for 4 hours at a liquid temperature of 90 ° C. while performing nitrogen bubbling, and then the oil bath temperature was raised to 120 ° C. and stirred for 2 hours to obtain a solution containing a prepolymer.

(Crystalline macromonomer)
While the liquid temperature of the solution containing the prepolymer was lowered to 90 ° C. and bubbling with mixed air, 10.3 parts of diacrylic anhydride as a functionalizing agent was added and stirred for 1 hour, and then 2.4 parts of water was added. And stirred for another 20 minutes. Next, a Dean Stark was attached to the beaker, and the oil bath temperature was 120 ° C., followed by stirring for 1 hour. Then, after removing water and toluene collected in the Dean Stark from the reaction system, the Dean Stark was removed from the beaker to obtain a copolymer in a solution state accommodated in the beaker. The weight average molecular weight and melting point of the obtained copolymer are as follows.
Weight average molecular weight: 3,900
Melting point: 55 ° C

(Side-chain crystalline polymer)
Next, the liquid temperature was lowered to 70 ° C., 19.6 parts of methyl acrylate as an amorphous monomer and 5.9 parts of 1-dodecanethiol as a chain transfer agent were added, and nitrogen bubbling was performed for 30 minutes. Then, 1.96 parts of “Perbutyl ND” manufactured by NOF Corporation as a polymerization initiator was dissolved in 30 parts of toluene as a polymerization solvent, and stirred at a liquid temperature of 70 ° C. for 4 hours. The mixture was raised to ° C. and stirred for 2 hours to obtain a copolymer. The weight average molecular weight and melting point of the obtained copolymer are as follows.
Weight average molecular weight: 5,540
Melting point: 52 ° C

[Comparative synthesis example: Side chain crystalline polymer]
40 parts of behenyl acrylate, 35 parts of stearyl acrylate, 20 parts of methyl acrylate, 5 parts of acrylic acid, 6 parts of dodecyl mercaptan as a chain transfer agent, and 1.0 part of “Perhexyl PV” manufactured by NOF Corporation as a polymerization initiator In addition to 100 parts of toluene, the mixture was stirred at 80 ° C. for 5 hours to polymerize these monomers. The weight average molecular weight and melting point of the obtained copolymer are as follows.
Weight average molecular weight: 7,840
Melting point: 48 ° C

In the synthesis examples 1 and 2 and the comparative synthesis example described above, the weight average molecular weight is a value obtained by measuring the copolymer with GPC and converting the obtained measurement value into polystyrene. The melting point is a value measured using DSC under measurement conditions of 10 ° C./min.

[Example 1 and Comparative Example]
A temperature-sensitive adhesive tape was prepared using the side chain crystalline polymer obtained in Synthesis Example 2 and Comparative Synthesis Example described above and the pressure-sensitive adhesive obtained in Synthesis Example 1, and the 180 ° peel strength was evaluated. The production procedure and evaluation method of the temperature-sensitive adhesive tape are shown below, and the results are shown in Table 1.

(Preparation of temperature-sensitive adhesive tape)
First, for 100 parts of the copolymer solution of the pressure-sensitive adhesive obtained in Synthesis Example 1, 3 parts of the side chain crystalline polymer obtained in Synthesis Example 2 or Comparative Synthesis Example in terms of solid content, and an isocyanate-based crosslinking agent Was added to obtain an adhesive solution. Next, the obtained pressure-sensitive adhesive solution was applied to one side of a 25 μm-thick polyethylene terephthalate film and heated at 100 ° C. for 10 minutes to cause a crosslinking reaction, thereby forming a 40 μm-thick pressure-sensitive adhesive layer. Was made. The temperature-sensitive adhesive tape using the side-chain crystalline polymer obtained in Synthesis Example 2 was evaluated as Example 1, and the temperature-sensitive adhesive tape using the side-chain crystalline polymer obtained in Comparative Synthesis Example was evaluated as a comparative example. did.

(Evaluation of 180 ° peel strength)
About the obtained temperature-sensitive adhesive tape, the initial temperature, (melting point of side chain crystalline polymer (hereinafter sometimes referred to as “Tm”) − 10) ° C. and (Tm + 10) ° C. and stainless steel plate at each atmospheric temperature 180 ° peel strength was measured according to JIS Z0237. Specifically, after the temperature-sensitive adhesive tape is attached to a stainless steel plate at an ambient temperature of 23 ° C. and the ambient temperature is adjusted to the measurement temperature, the temperature-sensitive adhesive tape is 180 ° at a speed of 300 mm / min with a load cell. It peeled. The initial temperature is 23 ° C.

From the measured value of 180 ° peel strength at the initial temperature, the adhesive physical properties were evaluated according to the following criteria.
○: 5N / 25mm or more ×: Less than 5N / 25mm

From the measured value of 180 ° peel strength at (Tm−10) ° C., the adhesive physical properties were evaluated according to the following criteria. The retention rate is a value calculated from the formula: [(Tm−10) ° C. peel strength / initial temperature peel strength] × 100.
○: 3N / 25mm or more and retention rate 70% or more ×: Less than 3N / 25mm or retention rate 70%

From the measured value of 180 ° peel strength at (Tm + 10) ° C., the adhesive physical properties were evaluated according to the following criteria. The rate of decrease is a value calculated from the formula: {[Peel strength at (Tm-10) ° C.−Peel strength at (Tm + 10) ° C.] / Peel strength at (Tm−10) ° C.} × 100.
○: 0.5 N / 25 mm or less and a reduction rate of 80% or more ×: More than 0.5 N / 25 mm or less than 80%

As is clear from Table 1, Example 1 showed a result that was superior in retention rate and higher in reduction rate than the comparative example. From this result, Example 1 can sufficiently maintain the initial adhesive strength (180 ° peel strength at the initial temperature) at a temperature lower than the melting point, and can sufficiently reduce the adhesive strength at a temperature higher than the melting point. I understand.

[Synthesis Example 3: Side chain crystalline polymer]
(Prepolymer)
First, 24.5 parts of behenyl acrylate as a crystalline monomer, 22.1 parts of stearyl acrylate, 2.5 parts of acrylic acid as another monomer, 5.9 parts of mercaptoethanol as a chain transfer agent, and 122 parts of toluene as a polymerization solvent The solution was heated to 80 ° C. in an oil bath and bubbled with nitrogen for 30 minutes. Next, 0.49 part of AIBN as a polymerization initiator was dissolved in 30 parts of toluene and charged into a beaker. Then, after stirring for 3 hours at a liquid temperature of 80 ° C. while performing nitrogen bubbling, the oil bath temperature was raised to 100 ° C. and stirred for 2 hours to obtain a solution containing a prepolymer.

(Crystalline macromonomer)
While the liquid temperature of the solution containing the prepolymer was lowered to 80 ° C. and bubbling with mixed air, 21.3 parts of 2-isocyanatoethyl acrylate “Karenz AOI” manufactured by Showa Denko KK as a functionalizing agent, and solid One part of dibutyltin dilaurate was added to a total of 100 parts of the prepolymer and 2-isocyanatoethyl acrylate in terms of minutes, and the mixture was stirred for 1 hour to obtain a copolymer in a solution state accommodated in a beaker.

The molar ratio of 2-isocyanatoethyl acrylate to mercaptoethanol (2-isocyanatoethyl acrylate / mercaptoethanol) is 2. The weight average molecular weight and melting point of the obtained copolymer, and the reaction rate of the prepolymer and 2-isocyanatoethyl acrylate estimated from ¹ H-NMR are as follows.
Weight average molecular weight: 4,200
Melting point: 58 ° C
Reaction rate: 100%

(Side-chain crystalline polymer)
Next, the liquid temperature was lowered to 80 ° C., 49 parts of methyl acrylate as an amorphous monomer and 11.8 parts of 1-dodecanethiol as a chain transfer agent were added, and nitrogen bubbling was performed for 30 minutes. Then, 1.37 parts of “Perbutyl ND” manufactured by NOF Corporation as a polymerization initiator was dissolved in 30 parts of toluene as a polymerization solvent and stirred at a liquid temperature of 80 ° C. for 3 hours. The mixture was raised to ° C. and stirred for 2 hours to obtain a copolymer. The weight average molecular weight and melting point of the obtained copolymer are as follows.
Weight average molecular weight: 9,000
Melting point: 54 ° C

[Synthesis Example 4: Side chain crystalline polymer]
(Prepolymer and crystalline macromonomer)
First, a solution containing a prepolymer was obtained in the same manner as in Synthesis Example 3 described above. Next, Synthesis Example 3 described above, except that the amount of 2-isocyanatoethyl acrylate “Karenz AOI” manufactured by Showa Denko Co., Ltd., which is a functionalizing agent, was changed to 16.0 parts instead of 21.3 parts. In the same manner as above, a solution state copolymer contained in a beaker was obtained.

The molar ratio of 2-isocyanatoethyl acrylate to mercaptoethanol (2-isocyanatoethyl acrylate / mercaptoethanol) is 1.5. The weight average molecular weight and melting point of the obtained copolymer, and the reaction rate of the prepolymer and 2-isocyanatoethyl acrylate estimated from ¹ H-NMR are as follows.
Weight average molecular weight: 4,100
Melting point: 57 ° C
Reaction rate: 100%

(Side-chain crystalline polymer)
Except for using the obtained copolymer, methyl acrylate as an amorphous monomer was charged in the same manner as in Synthesis Example 3 to obtain a copolymer. The weight average molecular weight and melting point of the obtained copolymer are as follows.
Weight average molecular weight: 8,900
Melting point: 54 ° C

[Synthesis Example 5: Side chain crystalline polymer]
(Prepolymer and crystalline macromonomer)
First, a solution containing a prepolymer was obtained in the same manner as in Synthesis Example 3 described above. Next, Synthesis Example 3 described above except that the amount of 2-isocyanatoethyl acrylate “Karenz AOI” manufactured by Showa Denko KK, which is a functionalizing agent, was changed to 12.8 parts instead of 21.3 parts. In the same manner as above, a solution state copolymer contained in a beaker was obtained.

The molar ratio of 2-isocyanatoethyl acrylate to mercaptoethanol (2-isocyanatoethyl acrylate / mercaptoethanol) is 1.2. The weight average molecular weight and melting point of the obtained copolymer, and the reaction rate of the prepolymer and 2-isocyanatoethyl acrylate estimated from ¹ H-NMR are as follows.
Weight average molecular weight: 4,000
Melting point: 57 ° C
Reaction rate: 72%

(Side-chain crystalline polymer)
Except for using the obtained copolymer, methyl acrylate as an amorphous monomer was charged in the same manner as in Synthesis Example 3 to obtain a copolymer. The weight average molecular weight and melting point of the obtained copolymer are as follows.
Weight average molecular weight: 8,500
Melting point: 55 ° C

[Synthesis Example 6: Side chain crystalline polymer]
(Prepolymer and crystalline macromonomer)
First, a solution containing a prepolymer was obtained in the same manner as in Synthesis Example 3 described above. Next, Synthesis Example 3 described above, except that the amount of 2-isocyanatoethyl acrylate “Karenz AOI” manufactured by Showa Denko Co., Ltd., which is a functionalizing agent, was changed to 10.7 parts instead of 21.3 parts. In the same manner as above, a solution state copolymer contained in a beaker was obtained.

The molar ratio of 2-isocyanatoethyl acrylate to mercaptoethanol (2-isocyanatoethyl acrylate / mercaptoethanol) is 1. The weight average molecular weight and melting point of the obtained copolymer, and the reaction rate of the prepolymer and 2-isocyanatoethyl acrylate estimated from ¹ H-NMR are as follows.
Weight average molecular weight: 4,100
Melting point: 57 ° C
Reaction rate: 56%

(Side-chain crystalline polymer)
Except for using the obtained copolymer, methyl acrylate as an amorphous monomer was charged in the same manner as in Synthesis Example 3 to obtain a copolymer. The weight average molecular weight and melting point of the obtained copolymer are as follows.
Weight average molecular weight: 7,500
Melting point: 57 ° C

[Synthesis Example 7: Side chain crystalline polymer]
(Prepolymer)
First, 24.5 parts of behenyl acrylate as a crystalline monomer, 22.1 parts of stearyl acrylate, 2.5 parts of acrylic acid as another monomer, 5.9 parts of mercaptoethanol as a chain transfer agent, and 122 parts of toluene as a polymerization solvent The solution was heated to 90 ° C. in an oil bath and bubbled with nitrogen for 30 minutes. Next, 0.49 part of AIBN as a polymerization initiator was dissolved in 30 parts of toluene and charged into a beaker. The mixture was stirred for 4 hours at a liquid temperature of 90 ° C. while performing nitrogen bubbling, and then the oil bath temperature was raised to 120 ° C. and stirred for 2 hours to obtain a solution containing a prepolymer.

(Crystalline macromonomer)
While lowering the liquid temperature of the solution containing the prepolymer to 90 ° C. and bubbling with mixed air, 12.9 parts of diacrylic anhydride as a functionalizing agent was added and stirred for 1 hour, and then 1.5 parts of water was added. And stirred for another 20 minutes. The molar ratio of diacrylic anhydride to mercaptoethanol (diacrylic anhydride / mercaptoethanol) is 1.1.

Next, a Dean Stark was attached to the beaker, and the oil bath temperature was 120 ° C., followed by stirring for 1 hour. Then, after removing water and toluene collected in the Dean Stark from the reaction system, the Dean Stark was removed from the beaker to obtain a copolymer in a solution state accommodated in the beaker. The weight average molecular weight and melting point of the obtained copolymer, and the reaction rate of the prepolymer and functionalizing agent estimated from ¹ H-NMR are as follows.
Weight average molecular weight: 3,900
Melting point: 55 ° C
Reaction rate: 10%

(Side-chain crystalline polymer)
Next, the liquid temperature was lowered to 60 ° C., 49 parts of methyl acrylate as an amorphous monomer and 11.8 parts of 1-dodecanethiol as a chain transfer agent were added, and nitrogen bubbling was performed for 30 minutes. Then, 1.37 parts of “Perbutyl ND” manufactured by NOF Corporation as a polymerization initiator was dissolved in 30 parts of toluene as a polymerization solvent, and stirred at a liquid temperature of 60 ° C. for 4 hours. The mixture was raised to ° C. and stirred for 2 hours to obtain a copolymer. The weight average molecular weight and melting point of the obtained copolymer are as follows.
Weight average molecular weight: 5,540
Melting point: 52 ° C

[Examples 2 to 6]
A temperature-sensitive adhesive tape was produced using the pressure-sensitive adhesive obtained in Synthesis Example 1 in the same manner as in Example 1 except that the side chain crystalline polymer obtained in Synthesis Examples 3 to 7 was used. did. And 180 degree peel strength was evaluated like Example 1 mentioned above except having used the produced temperature sensitive adhesive tape. The results are shown in Table 2.

As is clear from Table 2, Examples 2 to 6 all showed excellent retention rates and high reduction rates.

Claims (12)

1. Side chain crystalline polymer consisting of a graft copolymer of crystalline macromonomer and amorphous monomer.
2. The crystalline macromonomer is obtained by radical polymerization of (meth) acrylate having a linear alkyl group having at least 16 carbon atoms in the presence of a chain transfer agent having a hydroxyl group. Having a linear alkyl group having 16 or more carbon atoms in the side chain, obtained by reacting a prepolymer having di (meth) acrylic anhydride or a (meth) acrylate having an isocyanato group; The side-chain crystalline polymer according to claim 1, which is a macromonomer having a polymerizable double bond polymerizable with the non-crystalline monomer at a terminal.
3. The crystalline macromonomer is obtained by radical polymerization of (meth) acrylate having a linear alkyl group having at least 16 carbon atoms in the presence of a chain transfer agent having a hydroxyl group. It is obtained by reacting a (meth) acrylate having an isocyanato group with a prepolymer having a linear alkyl group having 16 or more carbon atoms in the side chain, and polymerized with the non-crystalline monomer at one end. A macromonomer having a polymerizable double bond possible,
   The molar ratio of the (meth) acrylate having an isocyanato group and the chain transfer agent having a hydroxyl group ((meth) acrylate having an isocyanato group / chain transfer agent having a hydroxyl group) is 1.0 to 2.0. The side-chain crystalline polymer according to claim 1.
4. The side chain crystalline polymer according to claim 2 or 3, wherein the (meth) acrylate having an isocyanato group is 2-isocyanatoethyl (meth) acrylate.
5. The side chain crystalline polymer according to any one of claims 1 to 4, wherein the crystalline macromonomer has a weight average molecular weight of 10,000 or less.
6. The non-crystalline monomer is at least one selected from a (meth) acrylate having an alkyl group having 1 to 12 carbon atoms, a polar monomer, a reactive polysiloxane compound, vinyl acetate, and styrene. The side chain crystalline polymer according to any one of the above.
7. The side chain crystalline polymer according to any one of claims 1 to 5, wherein the non-crystalline monomer is a (meth) acrylate having an alkyl group having 1 to 12 carbon atoms.
8. The side chain crystalline polymer according to any one of claims 1 to 5, wherein the non-crystalline monomer contains at least methyl acrylate.
9. The side chain crystalline polymer according to any one of claims 1 to 8, wherein the weight average molecular weight is larger than the weight average molecular weight of the crystalline macromonomer and is 20,000 or less.
10. A temperature-sensitive adhesive comprising an acrylic pressure-sensitive adhesive and the side-chain crystalline polymer according to any one of claims 1 to 9, wherein the adhesive strength decreases at a temperature equal to or higher than the melting point of the side-chain crystalline polymer. Adhesive.
11. A temperature-sensitive adhesive sheet comprising the temperature-sensitive adhesive according to claim 10.
12. A temperature-sensitive adhesive tape comprising: a substrate film; and an adhesive layer comprising the temperature-sensitive adhesive according to claim 10 laminated on at least one surface of the substrate film.