KR20150112871A - Temperature sensitive adhesive - Google Patents

Abstract

A temperature sensitive adhesive of the present invention comprises a tackifier and a side chain crystalline polymer, with reduced adhesive power at temperatures of the side chain crystalline polymer below a melting point, wherein the tackifier has a softening point greater than or equal to 140°C and 40-100 parts by weight of the contents with respect to 100 parts by weight of the side chain crystalline polymer. Accordingly, the adhesive is capable of reducing a rate of the side chain crystalline polymer of the temperature sensitive adhesive with a proper degree, and consequently, improving detachability by significantly reducing adhesive power regarding the temperature below the melting point.

Description

{TEMPERATURE SENSITIVE ADHESIVE}

The present invention relates to a thermosensitive adhesive.

A flat panel display (FPD), and the like, and an adhesive sheet, an adhesive tape, or the like is used for temporary fixing of a substrate made of glass, plastic or the like. In the adhesive tape used for such a use, the peeling property is required for re-peeling the adhesive tape once attached.

The present applicant has developed a pressure-sensitive adhesive tape described in Patent Document 1 as a pressure-sensitive adhesive tape suitable for temporary fixing. In the thermosensitive adhesive tape, the pressure-sensitive adhesive layer contains a side chain crystalline polymer. When the side chain crystalline polymer is cooled to a temperature lower than the melting point of the side chain crystalline polymer, the side chain crystalline polymer is crystallized to lower the adhesive force.

However, even when using the conventional heat-sensitive adhesive tape as described in Patent Document 1, the substrate may be broken at the time of peeling. In such a case, it is necessary to cool the substrate to a temperature lower than the room temperature (23 占 폚) (for example, 5 占 폚) in order to peel off without damaging the substrate. For this reason, the conventional heat sensitive adhesive tape requires a process of cooling to a temperature lower than the room temperature, and as a result, a facility or environment is required, and in some cases, the cost is increased. This problem was remarkable when the thermosensitive adhesive tape was peeled from the substrate exposed under a high temperature atmosphere of 100 DEG C or more together with the thermosensitive adhesive tape.

Japanese Patent Application Laid-Open No. 9-251923

A problem to be solved by the present invention is to provide a pressure-sensitive adhesive having excellent releasability.

The thermosensitive pressure-sensitive adhesive of the present invention contains a tackifier and a side chain crystalline polymer. The tackifier has a softening point lower than the melting point of the side chain crystalline polymer. The tackifier has a softening point of 140 ° C or higher, Is 40 to 100 parts by weight based on 100 parts by weight of the crystalline polymer.

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

≪ Temperature Sensitive Adhesive >

Hereinafter, the thermosensitive adhesive according to one embodiment of the present invention will be described in detail.

The thermosensitive pressure-sensitive adhesive of the present embodiment contains a side chain crystalline polymer and the adhesive strength is lowered at a temperature lower than the melting point of the side chain crystalline polymer.

(Side chain crystalline polymer)

The side chain crystalline polymer is a polymer having a melting point and crystallizes at a temperature lower than the melting point, and exhibits fluidity at a temperature higher than the melting point. That is, the side chain crystalline polymer has a thermosensitive property that reversibly causes a crystalline state and a flow state in response to a temperature change. As a result, it is possible to give the thermosensitive pressure-sensitive adhesive a physical property that reversibly causes sticking-non sticking in response to a temperature change.

The melting point is a temperature at which a specific portion of a polymer that has been initially aligned in an ordered arrangement by a certain equilibrium process becomes a disordered state and a value obtained by measurement under a measurement condition of 10 占 폚 / minute by a differential scanning calorimeter (DSC) .

The thermosensitive pressure-sensitive adhesive of the present embodiment contains a side chain crystalline polymer in such a ratio that the adhesive strength decreases when the side chain crystalline polymer is crystallized at a temperature lower than the melting point. That is, since the thermosensitive adhesive of the present embodiment contains the side chain crystalline polymer as a main component and is substantially composed of the side chain crystalline polymer, when the thermosensitive adhesive is peeled from the adherend, the thermosensitive pressure- , The side chain crystalline polymer is crystallized to lower the adhesive force. When the thermosensitive pressure-sensitive adhesive is heated to a temperature not lower than the melting point of the side chain crystalline polymer, the side chain crystalline polymer exhibits fluidity so that the adhesive force can be restored.

The melting point of the side chain crystalline polymer is preferably 24 占 폚 or higher, more preferably 25 占 폚 or higher, and still more preferably 26 占 폚 or higher. As a result, the side chain crystalline polymer is crystallized at room temperature (23 DEG C), so that room temperature peeling becomes possible. The upper limit of the melting point is preferably 60 占 폚 or lower. The melting point can be adjusted by changing the composition and the like of the side chain crystalline polymer.

The side chain crystalline polymer is not particularly limited as long as it is a polymer having a thermosensitive property that reversibly causes a crystalline state and a fluidized state in response to a temperature change, but is preferably composed of a copolymer of a reactive fluorine compound and other monomer constituting the side chain crystalline polymer Do. Thus, when the thermosensitive pressure-sensitive adhesive is cooled to a temperature lower than the melting point of the side chain crystalline polymer, in addition to the deterioration of the adhesive force due to crystallization of the side chain crystalline polymer, the moldability due to the fluorine compound is also added, It can be easily peeled off from the adherend.

The reactive fluorine compound means a fluorine compound having a functional group showing reactivity. Examples of the functional group exhibiting reactivity include groups having an ethylenically unsaturated double bond such as a vinyl group, an allyl group, a (meth) acrylic group, a (meth) acryloyl group, or a (meth) An epoxy group (including a glycidyl group and an epoxycycloalkyl group); A mercapto group; Carbinols; A carboxyl group; Silanol groups; A phenolic group; An amino group; And a hydroxyl group.

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

(Wherein R ₁ represents a group: 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 in the general formula (I) include a methylene group, an ethylene group, a trimethylene group, a methylethylene group, a propylene group, a tetramethylene group, a pentamethylene group and a hexamethylene group, To six linear or branched alkylene groups, and the like.

Specific examples of the compound represented by the general formula (I) include compounds represented by the following formulas (Ia) and (Ib).

Commercially available reactive fluorine compounds may be used. As commercially available reactive fluorine compounds, for example, all are available from Osaka Organic Chemical Industry Ltd. Viscoat 3F, Viscoat 3FM, Viscoat 4F, Viscoat 8F, Viscoat 8FM, KYOEISHA CHEMICAL CO., LTD. And "LIGHT ESTERM-3F" of the product.

Examples of other monomers constituting the side chain crystalline polymer include (meth) acrylates having a linear alkyl group having at least 16 carbon atoms, (meth) acrylates having an alkyl group having 1 to 6 carbon atoms, polar monomers, etc. .

Examples of the (meth) acrylate having a straight chain alkyl group having 16 or more carbon atoms include cetyl (meth) acrylate, stearyl (meth) acrylate, eicosyl (meth) acrylate, (Meth) acrylates having a linear alkyl group having from 16 to 22 carbon atoms. 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 hexyl (meth) . Examples of the polar monomer include a carboxyl group-containing ethylenically unsaturated monomer such as acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid, and fumaric acid; And ethylenically unsaturated monomers having a hydroxyl group such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate and 2-hydroxyhexyl (meth) acrylate. These may be used alone or in combination of two or more. Further, (meth) acrylate means acrylate or methacrylate.

It is preferable that the side chain crystalline polymer is a (meth) acrylate having at least 16 carbon atoms and preferably at least 18 carbon atoms in the respective monomers described above as the other monomers constituting the side chain crystalline polymer. The side chain crystalline polymer is preferably a (meth) acrylate having a linear alkyl group having at least 16 carbon atoms, a (meth) acrylate having an alkyl group having 1 to 6 carbon atoms and a polar monomer May be used as other monomers constituting the side chain crystalline polymer. In particular, the side chain crystalline polymer is preferably made of stearyl acrylate, methyl acrylate and acrylic acid as other monomers constituting the side chain crystalline polymer. In this case, the polymerization ratio of methyl acrylate is preferably larger than the polymerization ratio of stearyl acrylate and the polymerization ratio of acrylic acid.

The composition of the side chain crystalline polymer is preferably a copolymer obtained by polymerizing the reactive fluorine compound and the other monomers constituting the side chain crystalline polymer in a weight ratio of 1: 99 to 20: 80, preferably 1:99 to 10:90 .

The composition of the side chain crystalline polymer is preferably 10 to 99 parts by weight of (meth) acrylate having 1 to 20 parts by weight, preferably 1 to 10 parts by weight, of a reactive fluorine compound and a linear alkyl group having 16 or more carbon atoms, (Meth) acrylate having an alkyl group having 1 to 6 carbon atoms and 0 to 10 parts by weight of a polar monomer, and the reactive fluorine compound (Meth) acrylate having a straight chain alkyl group having 16 or more carbon atoms, and 60 to 65 parts by weight of a (meth) acrylate having an alkyl group having 1 to 6 carbon atoms and a polar And a copolymer obtained by polymerizing monomers at a ratio of 1 to 10 parts by weight is more preferable.

The weight average molecular weight of the side chain crystalline polymer is preferably 100,000 or more, more preferably 300,000 to 900,000, and still more preferably 400,000 to 600,000. When the weight average molecular weight is too small, the thermosensitive adhesive may remain on the adherend when the thermosensitive adhesive is peeled from the adherend, which may result in a large amount of adhesive residue. If the weight average molecular weight is too large, the crystallization becomes difficult even when the side chain crystalline polymer is heated to a temperature lower than the melting point, so that the adhesive force is less likely to deteriorate. The weight average molecular weight is a value obtained by converting a measured value of the side chain crystalline polymer by gel permeation chromatography (GPC) into polystyrene.

(Tackifier)

The thermosensitive pressure-sensitive adhesive of the present embodiment further contains a tackifier in addition to the above-described side chain crystalline polymer. The tackifier of the present embodiment has a softening point of 140 캜 or higher, preferably 150 캜 or higher. The upper limit value of the softening point is not particularly limited, but the tackifier having an excessively high softening point is generally 170 deg. C or lower, preferably 165 deg. C or lower, because preparation is difficult. The softening point is a value measured according to the ring method defined in JIS K 5902.

In the present embodiment, the above-mentioned tackifier is contained in an amount of 40 to 100 parts by weight, preferably 50 to 100 parts by weight, based on 100 parts by weight of the side chain crystalline polymer. When the high-softening point tackifier having a softening point of 140 ° C or higher at such a high ratio is contained, the ratio of the side chain crystalline polymer in the thermosensitive pressure-sensitive adhesive can be reduced to an appropriate level while maintaining the tackiness necessary for fixing the adherend, The adhesive strength is sufficiently lowered, and as a result, the peelability is improved. That is, according to this embodiment, the peelability can be easily improved by containing the tackifier having a high softening point at a specified ratio without changing the composition of the side chain crystalline polymer. Thus, for example, when the melting point of the side chain crystalline polymer is 24 占 폚 or higher, it is possible to reliably peel at room temperature without cooling to a temperature lower than room temperature (23 占 폚) (for example, 5 占 폚). Further, since the thermosensitive pressure-sensitive adhesive of the present embodiment is excellent in peelability, even if the adhered adherend is exposed to a temperature of 100 to 220 캜, the adherend can be removed smoothly by cooling to a temperature lower than the melting point.

The composition of the tackifier is not particularly limited as long as the softening point is not lower than 140 占 폚. Examples of the tackifier include a rosin resin, a terpene resin, a hydrocarbon resin, an epoxy resin, a polyamide resin, a phenol resin, These may be used alone or in combination of two or more. Of the tackifiers mentioned above, rosin-based resins are preferable because they are excellent in compatibility with the above-described side chain crystalline polymer.

Examples of the rosin-based resin include rosin derivatives and the like. Examples of the rosin derivatives include rosin ester compounds obtained by esterifying unmodified rosins (rosins) such as gum rosin, wood rosin and tall oil rosin with alcohols, and condensation rosin such as hydrogenated rosin, disproportionated rosin, Rosin esters such as ester compounds of modified rosin esterified by alcohols; Rosin metal salts such as unmodified rosin, modified rosin and various rosin derivatives; And rosin phenol resins obtained by adding phenol to an acid catalyst, such as unmodified rosin and modified rosin, and various rosin derivatives, and thermally polymerizing them.

Among these exemplified rosin derivatives, polymerized rosin esters are particularly preferable. Commercially available polymeric rosin esters can be used. Specific examples include Arakawa Chemical Industries, Ltd. And "PENSEL D-160" of the product.

(Crosslinking agent)

The thermosensitive adhesive preferably contains a crosslinking agent. Examples of the crosslinking agent include metal chelate compounds and aziridine compounds, and metal chelate compounds are particularly preferred. When a metal chelate compound is employed as the crosslinking agent, the heat resistance of the thermosensitive adhesive tends to be improved.

Examples of the metal chelate compound include an acetylacetone coordination compound of polyvalent metal, acetoacetic acid ester coordination compound, and the like. Examples of the polyvalent metal include aluminum, nickel, chromium, iron, titanium, zinc, cobalt, manganese and zirconium. These may be used alone or in combination of two or more. Among these exemplified metal chelate compounds, an acetylacetone coordination compound of aluminum or an acetoacetic acid ester coordination compound is preferable, and aluminum trisacetylacetonate is suitable.

The content of the crosslinking agent is preferably 0.1 to 12 parts by weight based on 100 parts by weight of the side chain crystalline polymer. When a metal chelate compound is employed as the crosslinking agent, the content is preferably 0.1 to 12 parts by weight, more preferably 5 to 12 parts by weight, and even more preferably 8 to 12 parts by weight based on 100 parts by weight of the side chain crystalline polymer .

(additive)

The thermosensitive adhesive may contain various additives such as a plasticizer, an anti-aging agent, and an ultraviolet absorber.

≪ Method of producing thermosensitive pressure-sensitive adhesive &

The method for producing the thermosensitive pressure-sensitive adhesive is not particularly limited. For example, a tackifier is added to a copolymer solution obtained by mixing a side chain crystalline polymer obtained by polymerizing a monomer constituting the side chain crystalline polymer with a solvent to obtain a coating liquid, And a method of drying the coating liquid.

The polymerization method of the side chain crystalline polymer 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 adopted. For example, when employing a solution polymerization method, the above-mentioned monomers constituting the side chain crystalline polymer may be mixed in a solvent and stirred at about 40 to 90 DEG C for about 2 to 10 hours. As the solvent, known ones can be used. When a crosslinking agent or an additive is contained in the thermosensitive adhesive, a crosslinking agent or an additive may be added to the copolymer solution.

<Temperature Sensitive Adhesive Sheet>

The thermosensitive pressure-sensitive adhesive sheet of the present embodiment is made of the above-mentioned thermosensitive pressure-sensitive adhesive, and is in the form of a sheet-like base article. The thickness of the thermosensitive adhesive sheet is not particularly limited, and is preferably 15 to 400 mu m. It is preferable to laminate a release film on the surface of the thermosensitive adhesive sheet. Examples of the release film include those obtained by applying a releasing agent such as silicone to the surface of a film made of, for example, polyethylene terephthalate.

<Temperature Sensitive Adhesive Tape>

The thermosensitive adhesive tape of the present embodiment is formed by laminating a pressure-sensitive adhesive layer comprising the above-mentioned thermosensitive pressure-sensitive adhesive on one side or both sides of a film-like substrate. That is, the structure of the thermosensitive adhesive tape has a two-layer structure composed of a film-like base material and a pressure-sensitive adhesive layer laminated on one side of the base material; Or a three-layer structure comprising a substrate on a film and a pressure-sensitive adhesive layer laminated on both sides of the substrate. The film phase is not limited to a film phase but is a concept including a film phase or a sheet phase as long as the effect of the present embodiment is not impaired.

Examples of the constituent material of the base material include polyethylene, polyethylene terephthalate, polypropylene, polyester, polyamide, polyimide, polycarbonate, ethylene vinyl acetate copolymer, ethylene ethyl acrylate copolymer, ethylene polypropylene copolymer, poly And synthetic resins such as vinyl chloride.

The substrate may be either a single-layer structure or a multi-layer structure, and its thickness is usually about 5 to 500 mu m. The substrate may be subjected to surface treatment such as corona discharge treatment, plasma treatment, blast treatment, chemical etching treatment, primer treatment or the like in order to improve adhesion to the pressure-sensitive adhesive layer.

In order to form the pressure-sensitive adhesive layer on one side or both sides of the substrate, for example, the above-mentioned coating liquid may be coated on one side or both sides of the substrate with a coater or the like and dried. Examples of the coater include a knife coater, a roll coater, a calendar coater, a comma coater, a gravure coater, and a rod coater.

The thickness of the pressure-sensitive adhesive layer is not particularly limited, and is preferably 5 to 60 占 퐉, more preferably 10 to 60 占 퐉, and still more preferably 10 to 50 占 퐉.

When the thermosensitive adhesive tape has a three-layer structure, the pressure-sensitive adhesive layer on one side and the pressure-sensitive adhesive layer on the other side may be the same or different in thickness and composition.

The pressure-sensitive adhesive layer on the other side may be composed of, for example, a pressure-sensitive adhesive layer made of a pressure-sensitive adhesive. The pressure-sensitive adhesive is a polymer having adhesiveness, and examples thereof include natural rubber adhesives, synthetic rubber adhesives, styrene / butadiene latex base adhesives, acrylic adhesives, and the like.

It is preferable to laminate a release film on the surface of the thermosensitive adhesive tape. Examples of the release film include those obtained by applying a releasing agent such as silicone to the surface of a film made of, for example, polyethylene terephthalate.

The above-described pressure-sensitive adhesive of the present embodiment can be suitably used as a pressure-sensitive adhesive in a field requiring this releasability. Specifically, the thermosensitive pressure-sensitive adhesive of the present embodiment is suitable for temporary fixation of a substrate made up of a large-sized and thinned glass or plastic in an LED, a FPD and the like, and is particularly suitable for temporary fixation of a plastic substrate in a manufacturing process of an FPD Can be used. This also applies to the thermosensitive adhesive sheet and thermosensitive adhesive tape of the present embodiment described above.

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, &quot; parts &quot; means parts by weight.

(Synthesis Example)

, 28 parts of stearyl acrylate, 62 parts of methyl acrylate, 5 parts of acrylic acid, and 5 parts of a reactive fluorine compound (Viscoat 3F, product of Osaka Organic Chemical Industry Ltd., represented by the above formula (Ia) Was added to 200 parts of a mixed solvent of ethyl acetate: toluene = 8: 2 (weight ratio), and the mixture was stirred at 55 占 폚 for 4 hours to polymerize these monomers. The weight average molecular weight of the obtained side chain crystalline polymer was 525,000 and the melting point was 26 ° C. The weight average molecular weight is a value obtained by converting a copolymer obtained by measuring by GPC into polystyrene. The melting point was a value measured at 10 ° C / min under the measurement conditions using DSC.

[Examples 1 to 4 and Comparative Examples 1 to 3]

<Production of a thermosensitive pressure-sensitive adhesive sheet>

First, the copolymer obtained in Synthesis Example was adjusted to a solid content of 30% by weight by using ethyl acetate to obtain a copolymer solution. Subsequently, a tackifier ("PENSEL D-160", a polymerization rosin ester having a softening point of 150 ° C or higher, manufactured by Arakawa Chemical Industries, Ltd.) was added to 100 parts of the copolymer solution in terms of solid content, 10 parts of trisacetylacetonate (manufactured by Kawaken Fine Chemicals Co., Ltd.) was further added thereto to obtain a coating liquid.

This coating liquid was coated on a release film and heated at 100 占 폚 for 10 minutes for crosslinking reaction to obtain a pressure sensitive adhesive sheet having a thickness of 25 占 퐉 and comprising a thermosensitive pressure-sensitive adhesive. As the release film, a polyethylene terephthalate film having a thickness of 50 mu m coated with silicon was used.

<Evaluation>

The resulting heat-sensitive pressure-sensitive adhesive sheet was evaluated for 180 ° peel strength. The evaluation method is shown below, and the results are shown in Table 1.

(180 DEG peel strength)

With respect to the obtained pressure-sensitive adhesive sheet, 180 deg. Peel strength at 50 deg. C and 23 deg. C at each atmospheric temperature was measured according to JIS Z0237. Specifically, a polyimide film ("100H" manufactured by DU PONT-TORAY CO., LTD.) Having a width of 25 mm and a thickness of 25 μm was passed through a thermosensitive adhesive sheet from which a release film had been removed, It was sticky. Subsequently, the adhesive polyimide film was peeled at 180 ° using a load cell at a rate of 300 mm / min.

(50 DEG C)

The polyimide film was adhered to the pedestal through the thermosensitive adhesive sheet at an atmospheric temperature of 50 占 폚, allowed to stand for 20 minutes, peeled by 180 占 and peel strength was measured. From the measurement of the peel strength, the adhesion was evaluated according to the following criteria.

?: 0.05 N / 25 mm or more

×: less than 0.05 N / 25 mm

(23 ° C)

The polyimide film was adhered to the pedestal through the thermosensitive pressure-sensitive adhesive sheet at an atmospheric temperature of 50 캜, the temperature was raised to 200 캜, and the temperature was allowed to stand at this atmospheric temperature for 20 minutes. Thereafter, After standing at a temperature for 20 minutes, it was peeled by 180 degrees and the peel strength was measured. The peelability was evaluated from the measurement of the peel strength by the following criteria.

?: 0.4 N / 25 mm or less

×: higher than 0.4 N / 25 mm

As apparent from Table 1, in Comparative Examples 1 and 2, since the content of the tackifier was less than 40 parts by weight based on 100 parts by weight of the side chain crystalline polymer, the ratio of the side chain crystalline polymer was excessively high, Temperature), while it has no peeling property at 23 占 폚 (room temperature).

In Examples 1 to 4, since the content of the tackifier is 40 to 100 parts by weight with respect to 100 parts by weight of the side chain crystalline polymer, peelability (peelability) at 23 deg. C (room temperature) . &Lt; / RTI &gt;

On the other hand, in Comparative Example 3, the content of the tackifier was more than 100 parts by weight with respect to 100 parts by weight of the side chain crystalline polymer, and the proportion of the side chain crystalline polymer was too low so that it did not stick even at 50 DEG C It is presumed.

In Comparative Example 1, the peel strength at 23 캜, which is lower than the melting point (26 캜), was higher than the peel strength at 50 캜, which is higher than the melting point. This is mainly attributed to the effect of the anchor effect. That is, in the measurement of the peel strength at 23 占 폚, since the thermosensitive adhesive sheet is once exposed to high temperature (200 占 폚), the anchor effect is exhibited in the cooling process and the adhesive strength is increased. In Comparative Example 1, since the content of the tackifier is small, the ratio of the side chain crystalline polymer is large, and therefore, the influence of the anchor effect is greatly exerted.

Claims (16)

Sensitive adhesive which contains a tackifier and a side chain crystalline polymer and whose adhesive strength is lowered at a temperature lower than the melting point of the side chain crystalline polymer,
Wherein the tackifier has a softening point of 140 ° C or higher and a content of 40-100 parts by weight per 100 parts by weight of the side chain crystalline polymer. The method according to claim 1,
Wherein the melting point is 24 占 폚 or higher. The method according to claim 1,
Sensitive adhesive, wherein the tackifier is a polymerized rosin ester. The method according to claim 1,
Wherein the side chain crystalline polymer is composed of a copolymer of a reactive fluorine compound and other monomer constituting the side chain crystalline polymer. 5. The method of claim 4,
Wherein the reactive fluorine compound is a compound represented by the following general formula (I).

(Wherein R ₁ represents a group: CH ₂ ═CHCOOR ² - or CH ₂ ═C (CH ₃ ) COOR ² - (wherein R ² represents an alkylene group) 5. The method of claim 4,
Wherein the other monomer constituting the side chain crystalline polymer is (meth) acrylate having at least a linear alkyl group having at least 16 carbon atoms. 5. The method of claim 4,
The other monomer constituting the side chain crystalline polymer is a (meth) acrylate having a linear alkyl group having at least 16 carbon atoms, (meth) acrylate having an alkyl group having 1 to 6 carbon atoms, and a polar monomer. 5. The method of claim 4,
Wherein the other monomer constituting the side chain crystalline polymer is stearyl acrylate, methyl acrylate, and acrylic acid. 9. The method of claim 8,
Wherein the polymerization ratio of the methyl acrylate is higher than the polymerization ratio of the stearyl acrylate and the polymerization ratio of the acrylic acid. The method according to claim 1,
Wherein the side chain crystalline polymer has a weight average molecular weight of 400,000 to 600,000. The method according to claim 1,
A pressure sensitive adhesive according to claim 1, further comprising a metal chelate compound. 12. The method of claim 11,
Wherein the content of the metal chelate compound is 8 to 12 parts by weight based on 100 parts by weight of the side chain crystalline polymer. The method according to claim 1,
Sensitive adhesive, wherein the adherend is exposed to a temperature of 100 to 220 캜 and then peeled off at a temperature lower than the melting point. The method according to claim 1,
A pressure sensitive adhesive which is used for temporarily fixing a plastic substrate in a manufacturing process of a flat panel display. Sensitive adhesive sheet characterized by comprising the thermosensitive adhesive according to any one of claims 1 to 5. A pressure-sensitive adhesive tape, comprising a pressure-sensitive adhesive layer comprising the pressure-sensitive adhesive according to claim 1 laminated on one side or both sides of a film-like substrate.