KR102453521B1 - Temperature-sensitive adhesive tape and temperature-sensitive adhesive sheet - Google Patents

Abstract

In the temperature-sensitive adhesive tape of the present invention, the pressure-sensitive adhesive layer laminated on one or both surfaces of a substrate is made of a cured product of the temperature-sensitive pressure-sensitive adhesive composition. The temperature-sensitive adhesive sheet of the present invention consists of a cured product of the temperature-sensitive adhesive composition. The temperature-sensitive adhesive composition contains at least a side chain crystalline (meth)acrylic polymer, a (meth)acryl monomer, a polyfunctional (meth)acrylate, and an optical radical initiator, and has ultraviolet curability and is liquid. In addition, the temperature-sensitive adhesive composition contains an optical radical initiator in a proportion of 0.2 to 1.9 parts by weight with respect to a total of 100 parts by weight of the side chain crystalline (meth)acrylic polymer and the (meth)acrylic monomer.

Description

Temperature-sensitive adhesive tape and temperature-sensitive adhesive sheet

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

As an adhesive tape which can control adhesive force reversibly by heat, a temperature-sensitive adhesive tape is known (for example, refer patent document 1).

However, since the conventional thermosensitive adhesive tape is formed of the adhesive layer containing the organic solvent, there existed a problem that the environmental load at the time of producing an adhesive tape was large.

On the other hand, as an adhesive which does not contain an organic solvent, an ultraviolet curable liquid adhesive is known. When an adhesive tape or an adhesive sheet is produced using such an adhesive, it is also thought that the problem by containing an organic solvent can be solved.

However, in conventional UV curable liquid adhesives, a large amount of unreacted monomers tend to remain in the cured product after UV curing, and when they volatilize, bubbles (outgas) are generated, adhesive strength is lowered, and peeling from the adherend is a problem. there was In particular, under a high-temperature environment, adhesion failures, such as the to-be-adhered body floating and peeling, were produced. In addition, there were also problems of odor and toxicity due to the presence of a large amount of unreacted monomers.

Japanese Patent Laid-Open No. 9-251923

SUMMARY OF THE INVENTION It is an object of the present invention to provide a temperature-sensitive adhesive tape and a temperature-sensitive adhesive sheet having low odor and low toxicity, and excellent heat resistance.

The temperature-sensitive adhesive tape of the present invention includes a film-shaped substrate and an adhesive layer laminated on one or both sides of the substrate, wherein the adhesive layer includes at least a side chain crystalline (meth)acrylic polymer, a (meth)acrylic monomer, and It contains a functional (meth)acrylate and a radical photoinitiator, has ultraviolet curability, and is composed of a cured product of a liquid temperature-sensitive adhesive composition, wherein the temperature-sensitive adhesive composition comprises the side chain crystalline (meth)acrylic polymer and the ( The said radical photoinitiator is contained in the ratio of 0.2-1.9 weight part with respect to a total of 100 weight part of meth)acryl monomers.

The temperature-sensitive adhesive sheet of the present invention contains at least a side-chain crystalline (meth)acrylic polymer, a (meth)acrylic monomer, a polyfunctional (meth)acrylate, and an optical radical initiator, and has ultraviolet curability and is a liquid temperature-sensitive adhesive Consists of a cured product of the composition, wherein the temperature-sensitive adhesive composition contains 0.2 to 1.9 parts by weight of the photo-radical initiator based on 100 parts by weight of the total of the side chain crystalline (meth)acrylic polymer and the (meth)acrylic monomer do.

ADVANTAGE OF THE INVENTION According to this invention, while being low odor and low toxicity, there exists an effect that it is excellent in heat resistance.

<Temperature Sensitive Adhesive Tape>

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

The temperature-sensitive adhesive tape of this embodiment is equipped with a base material and an adhesive layer.

(write)

The substrate of the present embodiment is in the form of a film. A film shape is not limited only to a film shape, As long as the effect of this embodiment is not impaired, a film shape thru|or a sheet shape is a concept also included. As a constituent material of the base material, for example, polyethylene, polyethylene terephthalate, polypropylene, polyester, polyamide, polyimide, polycarbonate, ethylene vinyl acetate copolymer, ethylene ethyl acrylate copolymer, ethylene polypropylene copolymer, poly Synthetic resins, such as vinyl chloride, are mentioned.

A single layer body or a multilayer body may be sufficient as a base material, and the thickness is usually about 5-500 micrometers. In order to improve the adhesiveness with respect to an adhesive layer to a base material, for example, surface treatment, such as a corona discharge treatment, a plasma treatment, a blast treatment, a chemical etching treatment, a primer treatment, can be given to a base material.

(Adhesive layer)

The adhesive layer of this embodiment is laminated|stacked on the single side|surface or both surfaces of the above-mentioned base material, It consists of a hardened|cured material which apply|coated the thermosensitive adhesive composition to a base material, and was irradiated with ultraviolet-ray and hardened|cured.

[Temperature-sensitive adhesive composition]

The temperature-sensitive adhesive composition (hereinafter, sometimes referred to as "adhesive composition") of this embodiment contains at least a side chain crystalline (meth)acrylic polymer, a (meth)acrylic monomer, a polyfunctional (meth)acrylate, and an optical radical initiator. In addition, it has UV curability which is hardened by irradiation of ultraviolet (Ultra Violet: hereinafter may be referred to as "UV"), and is liquid.

[Side-chain crystalline (meth)acrylic polymer]

The side chain crystalline (meth)acrylic polymer of this embodiment is a polymer obtained by polymerizing the (meth)acrylate which has a C16 or more linear alkyl group at least.

As for the (meth)acrylate which has a C16 or more linear alkyl group, the C16 or more linear alkyl group functions as a side chain crystalline moiety in a side chain crystalline (meth)acrylic polymer. That is, the side chain crystalline (meth)acrylic polymer is a comb-shaped polymer having a linear alkyl group having 16 or more carbon atoms in the side chain, and crystallizes by matching the side chains in an orderly arrangement by intermolecular force or the like.

And the side chain crystalline (meth)acrylic polymer of this embodiment has melting|fusing point regarding crystallization mentioned above. The melting point is the temperature at which a specific part of the polymer, which was initially aligned in an orderly arrangement, becomes disordered by a certain equilibrium process, and a value obtained by measuring with a differential thermal scanning calorimeter (DSC) at a measurement condition of 10°C/min. to mean

The side chain crystalline (meth)acrylic polymer of the present embodiment crystallizes at a temperature lower than the above-mentioned melting point, and has temperature sensitivity showing fluidity by undergoing a phase change at a temperature above the melting point. Therefore, the pressure-sensitive adhesive layer of the present embodiment made of a cured product of the pressure-sensitive adhesive composition containing the side-chain crystalline (meth) acrylic polymer exhibits adhesive force when the side-chain crystalline (meth) acrylic polymer flows at a temperature equal to or higher than the melting point, and When the side-chain crystalline (meth)acrylic polymer crystallizes at a temperature below the melting point, the adhesive force decreases. Further, when the pressure-sensitive adhesive layer is heated to a temperature equal to or higher than the melting point, the adhesive strength is restored by the side chain crystalline (meth)acrylic polymer exhibiting fluidity, so that it can be used repeatedly.

As the (meth)acrylate having a linear alkyl group having 16 or more carbon atoms constituting the side-chain crystalline (meth)acrylic polymer, for example, cetyl (meth)acrylate, stearyl (meth)acrylate, eicosyl (meth) (meth)acrylates having a linear alkyl group having 16 to 22 carbon atoms, such as acrylate and behenyl (meth)acrylate, are listed, and these may be used alone or as a mixture of two or more thereof. (meth)acrylate shall mean an acrylate or a methacrylate. This point also applies to other (meth)acrylates.

In addition, the side chain crystalline (meth)acrylic polymer of this embodiment can be further polymerized, for example, with (meth)acrylate having an alkyl group having 1 to 6 carbon atoms, a polar monomer, or the like.

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, hexyl (meth)acrylate, You may use these 1 type or in mixture of 2 or more types.

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; ethylenically unsaturated monomers having a hydroxyl group, such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, and 2-hydroxyhexyl (meth)acrylate; Or you may mix and use 2 or more types.

Each of the above-mentioned monomers is, for example, 20 to 100 parts by weight of (meth)acrylate having a linear alkyl group having 16 or more carbon atoms, 0 to 70 parts by weight of (meth)acrylate having an alkyl group having 1 to 6 carbon atoms, It is preferable to polymerize the polar monomer in a proportion of 0 to 10 parts by weight.

In addition, a reactive fluorine compound can be further polymerized to the side chain crystalline (meth)acrylic polymer of this embodiment, for example. Thereby, in addition to the fall of the adhesive force by a side chain crystalline (meth)acrylic polymer, the releasability resulting from a reactive fluorine compound is added, and the peelability of an adhesive layer can be improved.

A reactive fluorine compound shall mean the fluorine compound which has a functional group which shows reactivity. As a functional group which shows reactivity, for example. group which has ethylenically unsaturated double bond, such as a vinyl group, an allyl group, a (meth)acryl group, a (meth)acryloyl group, and a (meth)acryloyloxy group; and an epoxy group (including a glycidyl group and an epoxycycloalkyl group), a mercapto group, a carbinol group, a carboxyl group, a silanol group, a phenol group, an amino group, a hydroxyl group and the like.

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).]

As an alkylene group which R< ² > represents in general formula (I), For example, C1-C1-C such as a methylene group, an ethylene group, a trimethylene group, a methylethylene group, a propylene group, a tetramethylene group, a pentamethylene group, a hexamethylene group 6 straight-chain or branched alkylene groups and the like are exemplified.

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

A commercial item can be used for the above-mentioned reactive fluorine compound. As a commercially available reactive fluorine compound, all are OSAKA ORGANIC CHEMICAL IND. “Viscoat 3F”, “Viscoat 3FM”, “Viscoat 4F”, “Viscoat 8F”, “Viscoat 8FM” manufactured by LTD., “Light Ester M-3F” manufactured by KYOEISHA CHEMICAL Co., LTD, etc. This is listed

The reactive fluorine compound is preferably polymerized with the above-mentioned monomer in an amount of 1 to 10 parts by weight.

On the other hand, as melting|fusing point of a side chain crystalline (meth)acrylic polymer, it is preferable that it is 5-80 degreeC, and it is more preferable that it is 10-70 degreeC. Melting|fusing point can be adjusted by changing the composition etc. of a side chain crystalline (meth)acrylic polymer. Also, the melting point tends not to change substantially before and after UV irradiation. That is, the melting point after UV curing tends to be substantially the same as the melting point before UV curing.

As a weight average molecular weight of a side chain crystalline (meth)acrylic polymer, it is preferable that it is 450,000 or more, and it is more preferable that it is 1 million phases. Although it is preferable that it is 3 million or less as an upper limit of the weight average molecular weight of a side chain crystalline (meth)acrylic polymer, it is not limited to this. A weight average molecular weight is the value which carried out the standard polystyrene conversion of the measured value obtained by measuring by gel permeation chromatography (GPC). As a measurement solvent of GPC, tetrahydrofuran (THF) etc. are mentioned, for example.

The polymerization of the above-mentioned monomers is preferably performed by bulk polymerization. Thereby, an adhesive composition can be set as the state which does not contain an organic solvent. In addition, it is preferable to perform bulk polymerization while irradiating UV. Thereby, the monomer can be polymerized in a relatively short time. Therefore, the side chain crystalline (meth)acrylic polymer of the present embodiment is bulk polymerized while irradiating UV by adding a radical photoinitiator described later to a monomer containing (meth)acrylate having at least a linear alkyl group having 16 or more carbon atoms. It is preferably one polymer. In addition, a monomer is not limited only to an acryl-type monomer, As long as the (meth)acrylate which has a C16 or more linear alkyl group is included at least, a reactive fluorine compound etc. are included in concept.

As polymerization temperature in bulk polymerization, it is preferable that it is 30-60 degreeC. Moreover, as polymerization time, it is preferable that they are 30 second - 5 minutes. The intensity of UV is preferably 10 to 100 mW/cm ² (365 nm). In addition, polymerization conditions are not limited to the polymerization conditions mentioned above as long as a side chain crystalline (meth)acrylic polymer can be synthesize|combined.

Bulk polymerization may be performed in presence of a chain transfer agent in order to control molecular weight. As an addition amount of a chain transfer agent, it is preferable that it is 0.1-10 weight part with respect to 100 weight part of monomers. Examples of the chain transfer agent include, but are not limited to, thiol-based chain transfer agents such as dodecyl mercaptan.

[(meth)acrylic monomer]

As above-mentioned, the adhesive composition of this embodiment contains a (meth)acryl monomer. The adhesive composition of this embodiment originates in containing a (meth)acryl monomer, and is liquid. Therefore, the adhesive composition of this embodiment can exhibit outstanding applicability|paintability. Moreover, since the adhesive composition of this embodiment is liquid, it is not necessary to contain the organic solvent like the conventional thermosensitive adhesive. Therefore, according to the adhesive composition of this embodiment, there is no problem by containing the organic solvent mentioned above.

In order to acquire the effect mentioned above reliably, it is preferable that the adhesive composition of this embodiment does not contain the organic solvent. In addition, in this embodiment, the liquid phase shall mean that the viscosity in 50 degreeC of the mixture containing at least a side chain crystalline (meth)acrylic polymer and a (meth)acryl monomer is 100-10,000 mPa*g. A viscosity is a value before UV curing, and is a value obtained by measuring by the method described in the Example mentioned later.

The pressure-sensitive adhesive composition preferably has the most total content of the side chain crystalline (meth)acrylic polymer and the (meth)acrylic monomer. As a result, the pressure-sensitive adhesive composition contains a side chain crystalline (meth)acrylic polymer and a (meth)acrylic monomer as main components, and as a result, excellent applicability and adhesion properties can be exhibited.

Further, the pressure-sensitive adhesive composition preferably contains the side chain crystalline (meth)acrylic polymer in a proportion of 5 to 40 wt% with respect to 100 wt% of the total of the side chain crystalline (meth)acrylic polymer and the (meth)acrylic monomer. In other words, the pressure-sensitive adhesive composition preferably contains a (meth)acryl monomer in a proportion of 60 to 95% by weight with respect to a total of 100% by weight of the side chain crystalline (meth)acrylic polymer and the (meth)acryl monomer. According to these structures, the pressure-sensitive adhesive composition has a suitable viscosity, and therefore excellent applicability can be exhibited, and the (meth)acrylic monomer can be suppressed from remaining after UV curing, resulting in excellent adhesive properties. can

Here, the (meth)acryl monomer of this embodiment is the same as the monomer which comprises a side chain crystalline (meth)acryl polymer. Thereby, the (meth)acryl monomer can exhibit excellent compatibility with respect to the side chain crystallinity (meth)acryl polymer. The (meth)acryl monomer of this embodiment corresponds to the residual monomer at the time of superposing|polymerizing the above-mentioned monomer which comprises a side chain crystalline (meth)acryl polymer. Therefore, as the (meth)acryl monomer, the same monomers as those exemplified in the above-mentioned side chain crystalline (meth)acrylic polymer, that is, (meth)acrylate having a linear alkyl group having 16 or more carbon atoms, (meth)acrylate having an alkyl group having 1 to 6 carbon atoms ( meth)acrylates, polar monomers, and the like.

In this embodiment, it is preferable to polymerize the above-mentioned monomer constituting the side chain crystalline (meth)acrylic polymer so that the side chain crystalline (meth)acrylic polymer and the (meth)acrylic monomer coexist. Specifically, polymerizing the above-mentioned monomers so that the proportion of the side chain crystalline (meth)acrylic polymer is 5 to 40 wt% with respect to 100 wt% of the total of the side chain crystalline (meth)acrylic polymer and the (meth)acrylic monomer. desirable.

[Polyfunctional (meth)acrylate]

Polyfunctional (meth)acrylate is a curable compound having a property of curing by UV irradiation, and is a (meth)acrylate having two or more radically polymerizable double bonds in a molecule. As mentioned above, the adhesive composition of this embodiment can improve the cohesive force of an adhesive layer after UV curing from the point containing polyfunctional (meth)acrylate.

It is preferable that an adhesive composition contains a polyfunctional (meth)acrylate in the ratio of 0.1-30 weight part with respect to a total of 100 weight part of a side chain crystalline (meth)acrylic polymer, a (meth)acryl monomer, and an optical radical initiator.

Polyfunctional (meth)acrylate is bifunctional (meth)acrylate or trifunctional (meth)acrylate, and it is preferable that weight average molecular weights are 200-1,200, It is more preferable that it is 500-1,200, It is 1,000-1,200 It is more preferable that

Examples of the polyfunctional (meth)acrylate include 1,6-hexanediol di(meth)acrylate, ethoxylated bisphenol A di(meth)acrylate, ε-caprolactone-modified tris-(2-acryloxyethyl) isocyanurate etc. are mentioned, These may be used 1 type or in mixture of 2 or more types.

A commercial item can be used for the above-mentioned polyfunctional (meth)acrylate. As a commercially available polyfunctional (meth)acrylate, all are Shin-Nakamura Chemical Co., Ltd., for example. "NK Ester A-HD-N", "NK Ester A-BPE-10", "NK Ester A-930-1CL", "NK Ester A-9300-6CL" and the like of the product are listed.

[Photoradical Initiator]

The pressure-sensitive adhesive composition of the present embodiment contains an optical radical initiator as described above. A radical photoinitiator should just be a compound which can start radical polymerization by receiving light irradiation, and is not specifically limited. The radical photoinitiator of this embodiment is used at the time of polymerization of the above-mentioned monomer constituting the side chain crystalline (meth)acrylic polymer, and is also used at the time of UV curing of the pressure-sensitive adhesive composition.

Here, the adhesive composition of this embodiment contains an optical radical initiator in the ratio of 0.2-1.9 weight part with respect to a total of 100 weight part of a side chain crystalline (meth)acrylic polymer and a (meth)acryl monomer, Preferably it is 0.4- It contains in the ratio of 1.1 weight part, More preferably, it contains in the ratio of 0.6-1.1 weight part. When an optical radical initiator is contained in such a ratio, while being able to polymerize a monomer efficiently, it can suppress that an unreacted monomer remains after UV curing, Therefore, low odor and low toxicity can be achieved. Moreover, generation|occurrence|production of the bubble (outgas) by volatilization of the unreacted monomer which remained can be suppressed. As a result, the fall of the adhesive force by generation|occurrence|production of a bubble (outgas) can be suppressed, and excellent heat resistance can be exhibited with the improvement of the cohesion force by containing the polyfunctional (meth)acrylate mentioned above. In addition, the radical photoinitiator may add the whole amount at the time of superposition|polymerization of a monomer collectively, and may divide and add it, respectively at the time of superposition|polymerization of a monomer and UV curing of an adhesive composition.

A commercial item can be used for the above-mentioned radical photoinitiator. Commercially available radical photoinitiators are, for example, all manufactured by BASF Japan Co., Ltd. "IRGACURE 184", "IRGACURE 500", etc. of products are listed.

Various additives, such as a tackifier, anti-aging agent, and a crosslinking agent, can be added to the adhesive composition of this embodiment mentioned above, for example.

Moreover, as an application means for apply|coating the adhesive composition to the above-mentioned base material, an applicator, a coater, etc. are mentioned, for example. Examples of the coater include a knife coater, a roll coater, a calender coater, a comma coater, a gravure coater, and a rod coater.

Here, in this embodiment, as described above, after the pressure-sensitive adhesive composition is applied to the substrate, the pressure-sensitive adhesive composition is cured by irradiating UV, but the UV irradiation amount is 5,000 mJ/cm ² or more, preferably 7,000 mJ/cm ² It is better to be more than Thereby, it can suppress that an unreacted monomer remains after UV hardening with the effect by content of the above-mentioned optical radical initiator. Moreover, although it is preferable that it is 16,000 mJ/cm< ² > or less as an upper limit of the irradiation amount of UV, it is not limited to this.

When irradiating UV, it is preferable to laminate an air barrier member in the form of a film on the surface of the coating film made of the pressure-sensitive adhesive composition. Thereby, it can be hardened by irradiating UV to an adhesive composition in the state which blocked the air. Examples of the air barrier member include those in which a release agent such as silicone or silicone is applied to the surface of a film made of polyethylene terephthalate or the like.

As thickness of the adhesive layer of this embodiment, it is preferable that it is 5-60 micrometers, It is more preferable that it is 10-60 micrometers, It is more preferable that it is 10-50 micrometers. The thickness of the pressure-sensitive adhesive layer on one surface and the thickness of the pressure-sensitive adhesive layer on the other surface may be the same or different.

In addition, in this embodiment, as long as the adhesive layer of one side consists of the above-mentioned adhesive composition, the adhesive layer of the other side is not specifically limited. In the case where the pressure-sensitive adhesive layer on the other side is composed of, for example, the pressure-sensitive adhesive layer made of the above-described pressure-sensitive adhesive composition, the composition may be the same as or different from the composition of the pressure-sensitive adhesive layer on one side.

Further, the pressure-sensitive adhesive layer on the other surface may be constituted by, for example, a pressure-sensitive adhesive layer made of a pressure-sensitive adhesive. The pressure-sensitive adhesive is a polymer having tack, and examples thereof include a natural rubber adhesive, a synthetic rubber adhesive, a styrene/butadiene latex base adhesive, and an acrylic adhesive.

It is preferable to laminate a release film on the surface of the above-mentioned temperature-sensitive adhesive tape. As a release film, what apply|coated release agents, such as silicone and silicone, to the surface of the film which consists of polyethylene terephthalate etc. are mentioned, for example.

The use of the temperature-sensitive adhesive tape of the present embodiment is not particularly limited, and, for example, it can be preferably used as an adhesive tape in a field requiring low odor and low toxicity, and requiring use in a high-temperature environment.

<Temperature-sensitive adhesive sheet>

Next, a temperature-sensitive adhesive sheet according to an embodiment of the present invention will be described.

The temperature-sensitive adhesive sheet of this embodiment consists of a hardened|cured material which processed the adhesive composition which concerns on one Embodiment mentioned above into a sheet shape, and irradiated UV and hardened it. As thickness of a temperature-sensitive adhesive sheet, it is preferable that it is 15-400 micrometers, and it is more preferable that it is 20-150 micrometers.

Other configurations are the same as those of the temperature-sensitive adhesive tape according to the above-described embodiment, and thus the description thereof will be omitted.

As mentioned above, although preferred embodiment which concerns on this invention was illustrated, this invention is not limited to embodiment mentioned above, It cannot be overemphasized that it can be made into arbitrary things unless it deviates from the summary of this invention.

For example, in the above embodiment, the (meth)acryl monomer is a residual monomer when the monomer constituting the side chain crystalline (meth)acryl polymer is polymerized. You may make it contain in an adhesive composition not as a residual monomer but as a new monomer. Moreover, when a (meth)acryl monomer is a residual monomer at the time of superposing|polymerizing the monomer which comprises a side chain crystalline (meth)acryl polymer, you may make the adhesive composition contain a new (meth)acryl monomer further.

Hereinafter, the present invention will be described in more detail with reference to Synthesis Examples and Examples, but the present invention is not limited to the following Synthesis Examples and Examples.

(Synthesis Example 1)

First, in a 500 ml flask equipped with a nitrogen inlet tube, a thermometer, a cooling tube and a UV irradiation head on the upper part of the flask, 42 g of stearyl acrylate, 93 g of methyl acrylate, 7.5 g of acrylic acid, with the above formula (Ia) 7.5 g of the indicated 2,2,2-trifluoroethyl acrylate (reactive fluorine compound "Biscoat 3F" manufactured by OSAKA ORGANIC CHEMICAL IND. LTD.) and a photoradical initiator (photopolymerization initiator) manufactured by BASF Japan of "IRGACURE 500" was added in a ratio of 1.5 g, and a mixed solution was obtained. In addition, the ratio of the above-mentioned radical photoinitiator is a ratio of 1 weight part with respect to a total of 100 weight part of a side chain crystalline (meth)acrylic polymer and a (meth)acryl monomer.

Next, the flask was immersed in a hot water bath, the mixture was heated to 40 DEG C, and nitrogen was bubbled for 30 minutes while stirring at 150 rpm to remove oxygen in the mixture. And with respect to the liquid mixture, bulk polymerization of the monomer was carried out, irradiating UV from the UV irradiation head of the flask upper part.

The conditions for bulk polymerization are as follows.

Polymerization temperature: 40℃

Polymerization time: 2 minutes

Intensity of UV: 34 mW/cm ² (365 nm)

A liquid mixture of a side chain crystalline (meth)acrylic polymer and a (meth)acrylic monomer (stearyl acrylate, methyl acrylate, acrylic acid, 2,2,2-trifluoroethyl acrylate) was prepared by the bulk polymerization described above. got it The weight average molecular weight of the side chain crystalline (meth)acrylic polymer in the obtained liquid mixture, content of the side chain crystalline (meth)acrylic polymer and (meth)acryl monomer, and the viscosity of the liquid mixture were measured. Each measurement result and measurement method are as follows.

Weight average molecular weight of side chain crystalline (meth)acrylic polymer: 1.2 million

Content of side chain crystalline (meth)acrylic polymer: 7 wt%

Content of (meth)acrylic monomer: 93% by weight

Viscosity of liquid mixture: 1,000 mPa s

(weight average molecular weight)

It was measured by GPC, and the obtained measured value was converted into standard polystyrene, and was obtained. THF was used as the measurement solvent of GPC.

(content rate)

In the measurement result of the above-mentioned weight average molecular weight, it computed from the detection area ratio of a polymer powder and a monomer powder.

(viscosity)

It measured on the following measurement conditions.

Measuring device: Digital viscometer “DV-II+Pro” from EKO INSTRUMENTS

Cone Plate: CPE-42

RPM: 30rpm

Measuring temperature: 50℃

(Synthesis Example 2)

In the same manner as in Synthesis Example 1 described above, except that the ratio of the photoradical initiator (photopolymerization initiator) was 0.75 g instead of 1.5 g, the monomer was bulk polymerized while irradiated with UV, and the side chain crystalline (meth) acrylic polymer and ( A liquid mixture of meth)acrylic monomers was obtained. In addition, the ratio of the above-mentioned radical photoinitiator is a ratio of 0.5 weight part with respect to a total of 100 weight part of a side chain crystalline (meth)acrylic polymer and a (meth)acryl monomer.

The weight average molecular weight of the side chain crystalline (meth)acrylic polymer in the obtained liquid mixture, the content of the side chain crystalline (meth)acrylic polymer and (meth)acrylic monomer, and the viscosity of the liquid mixture were measured in the same manner as in Synthesis Example 1 described above. . The measurement results are as follows.

Weight average molecular weight of side chain crystalline (meth)acrylic polymer: 1.4 million

Content of side chain crystalline (meth)acrylic polymer: 7 wt%

Content of (meth)acrylic monomer: 93% by weight

Viscosity of liquid mixture: 1,200 mPa s

(Comparative Synthesis Example 1)

In the same manner as in Synthesis Example 1 above, except that the ratio of the photoradical initiator (photopolymerization initiator) was 0.15 g instead of 1.5 g, the monomer was bulk polymerized while irradiated with UV, and the side chain crystalline (meth)acrylic polymer and ( A liquid mixture of meth)acrylic monomers was obtained. In addition, the ratio of the above-mentioned radical photoinitiator is a ratio of 0.1 weight part with respect to a total of 100 weight part of a side chain crystalline (meth)acrylic polymer and a (meth)acryl monomer.

The weight average molecular weight of the side chain crystalline (meth)acrylic polymer in the obtained liquid mixture, the content of the side chain crystalline (meth)acrylic polymer and (meth)acrylic monomer, and the viscosity of the liquid mixture were measured in the same manner as in Synthesis Example 1 described above. . The measurement results are as follows.

Weight average molecular weight of side chain crystalline (meth)acrylic polymer: 2.2 million

Content of side chain crystalline (meth)acrylic polymer: 16 wt%

Content of (meth)acrylic monomer: 84% by weight

Viscosity of liquid mixture: 1600 mPa s

(Comparative Synthesis Example 2)

In the same manner as in Synthesis Example 1 described above, except that the ratio of the photoradical initiator (photopolymerization initiator) was 3.0 g instead of 1.5 g, the monomer was bulk polymerized while irradiated with UV, and the side chain crystalline (meth)acrylic polymer and ( A liquid mixture of meth)acrylic monomers was obtained. In addition, the ratio of the above-mentioned radical photoinitiator is a ratio of 2.0 weight part with respect to a total of 100 weight part of a side chain crystalline (meth)acrylic polymer and a (meth)acryl monomer.

The weight average molecular weight of the side chain crystalline (meth)acrylic polymer in the obtained liquid mixture, the content of the side chain crystalline (meth)acrylic polymer and (meth)acrylic monomer, and the viscosity of the liquid mixture were measured in the same manner as in Synthesis Example 1 described above. . The measurement results are as follows.

Weight average molecular weight of side chain crystalline (meth)acrylic polymer: 750,000

Content of side chain crystalline (meth)acrylic polymer: 5 wt%

Content of (meth)acrylic monomer: 95% by weight

Viscosity of liquid mixture: 700 mPa s

Example 1

<Production of temperature-sensitive adhesive sheet>

As the coating liquid, the liquid mixture obtained in Synthesis Example 1 was used. And first, polyfunctional acrylate was added in the ratio of 22.1 g (0.02 mol) with respect to 100 g of this liquid mixture.

The added polyfunctional acrylate is as follows.

Polyfunctional acrylate: ε-caprolactone-modified tris-(2-acryloxyethyl)isocyanurate "NK ester A-9300 manufactured by Shin-Nakamura Chemical Co., Ltd. which is trifunctional and has a weight average molecular weight of 1107 -6CL”

Next, after adding a tackifier in the ratio of 20 g with respect to 100 g of the liquid mixture to which the polyfunctional acrylate was added, the liquid mixture was apply|coated to the surface of the release film with an applicator.

The added tackifier is as follows.

Tackifier: ARAKAWA CHEMICAL INDUSTRIES, LTD. Polymerized rosin ester of the product “Pencel D-160”

The release film used is as follows.

Release film: Polyethylene terephthalate film “PET50×1-J0L” with a thickness of 50 μm in which the surface of Nippa Corporatin is silicone-treated

Then, a film-shaped air barrier member was laminated on the surface of the coating film, and UV was irradiated from above the coating film to obtain a temperature-sensitive adhesive sheet having a thickness of 40 µm.

In addition, the used air blocking member is as follows.

Air barrier member: Polyethylene terephthalate film "PET25×1-J0L" with a thickness of 25 μm with a silicone-treated surface of Nippa Corporatin

UV irradiation conditions are as follows.

UV irradiation device: "HLR100T-2/HB100A-1" manufactured by AS ONE CORPORATION

UV radiation dose: 8,000 mJ/cm ²

<Evaluation>

About the obtained temperature-sensitive adhesive sheet, an odor, an outgas, heat resistance, and peelability were evaluated. While each evaluation method is shown below, the result is shown in Table 1.

(stink)

The presence or absence of the monomer odor of the temperature-sensitive adhesive sheet was sensory-evaluated. The evaluation criteria were set as follows.

○: No monomer odor

×: There is a smell of monomer

(Outgas)

The temperature-sensitive adhesive sheet was exposed in a high-temperature atmosphere at 200°C, and the presence or absence of outgassing was evaluated by visually observing it. The evaluation criteria were set as follows.

○: No outgas

△: There is some outgas in the range where there is no problem in practical use

×: With outgas

(Heat resistance)

First, the release film and the air barrier member were separated from the temperature-sensitive adhesive sheet, a glass plate was adhered to one side of the temperature-sensitive adhesive sheet, and a polyimide film having a thickness of 25 µm was adhered to the other side to obtain a test piece. The heat resistance was evaluated by visually observing the state of the test piece obtained next, after making the polyimide film upward and a glass plate downward, loading the obtained test piece on a 150-250 degreeC hotplate, and leaving it still for 20 minutes. The evaluation criteria were set as follows. In addition, in the following evaluation criteria, float shall mean that a polyimide film and a glass plate float from a temperature-sensitive adhesive sheet.

◎: no change at 250℃

○: No change at a temperature of 200°C or higher and less than 250°C

△: No change at a temperature of 150°C or higher and less than 200°C

x: At 150 degreeC, foam|bubble and float generate|occur|produced.

(Peelability)

After evaluating the above-mentioned heat resistance, the polyimide film and the glass plate were placed on a cool plate at 5° C. with the polyimide film upward and the glass plate downward, and after standing for 20 minutes, the polyimide film and the glass plate were peeled by hand from the temperature-sensitive adhesive sheet. The peelability of the sensory evaluation was carried out. The evaluation criteria were set as follows.

○: Peelable without resistance

△: There is some resistance in the range where there is no problem in practical use, but peeling is possible

×: non-peelable

Example 2

As the coating liquid, a temperature-sensitive adhesive sheet having a thickness of 40 µm was obtained in the same manner as in Example 1 above except that the liquid mixture obtained in Synthesis Example 2 was used.

About the obtained temperature-sensitive adhesive sheet, it carried out similarly to Example 1 mentioned above, and evaluated odor, outgas, heat resistance, and peelability. The results are shown in Table 1.

Example 3

As the coating liquid, the liquid mixture obtained in Synthesis Example 2 was used, and the UV irradiation amount irradiated from above the coating film was 16,000 mJ/cm ² instead of 8,000 mJ/cm ² In the same manner as in Example 1 described above. Thus, a temperature-sensitive adhesive sheet having a thickness of 40 µm was obtained.

About the obtained temperature-sensitive adhesive sheet, it carried out similarly to Example 1 mentioned above, and evaluated odor, outgas, heat resistance, and peelability. The results are shown in Table 1.

Example 4

A temperature-sensitive adhesive sheet having a thickness of 40 µm was obtained in the same manner as in Example 1, except that 15.5 g (0.02 mol) of the polyfunctional acrylate shown below was added to 100 g of the liquid mixture.

Polyfunctional acrylate: ethoxylated bisphenol A diacrylate "NK ester A-BPE-10" manufactured by Shin-Nakamura Chemical Co., Ltd. which is bifunctional and has a weight average molecular weight of 776

About the obtained temperature-sensitive adhesive sheet, it carried out similarly to Example 1 mentioned above, and evaluated odor, outgas, heat resistance, and peelability. The results are shown in Table 1.

Example 5

A temperature-sensitive adhesive sheet having a thickness of 40 µm was obtained in the same manner as in Example 1 except that the polyfunctional acrylate shown below was added in a ratio of 10.7 g (0.02 mol) to 100 g of the liquid mixture.

Polyfunctional acrylate: ε-caprolactone-modified tris-(2-acryloxyethyl)isocyanurate "NK ester A-9300 manufactured by Shin-Nakamura Chemical Co., Ltd. which is trifunctional and has a weight average molecular weight of 537 -1CL”

About the obtained temperature-sensitive adhesive sheet, it carried out similarly to Example 1 mentioned above, and evaluated odor, outgas, heat resistance, and peelability. The results are shown in Table 1.

Example 6

A temperature-sensitive adhesive sheet having a thickness of 40 µm was obtained in the same manner as in Example 1, except that the polyfunctional acrylate shown below was added in a ratio of 4.5 g (0.02 mol) to 100 g of the liquid mixture.

Polyfunctional acrylate: 1,6-hexanediol diacrylate "NK ester A-HD-N" manufactured by Shin-Nakamura Chemical Co., Ltd. which is bifunctional and has a weight average molecular weight of 226

About the obtained temperature-sensitive adhesive sheet, it carried out similarly to Example 1 mentioned above, and evaluated odor, outgas, heat resistance, and peelability. The results are shown in Table 1.

Example 7

A temperature-sensitive adhesive sheet having a thickness of 40 µm was obtained in the same manner as in Example 1, except that the amount of UV irradiated from above the coating film was 16,000 mJ/cm ² instead of 8,000 mJ/cm ² .

About the obtained temperature-sensitive adhesive sheet, it carried out similarly to Example 1 mentioned above, and evaluated odor, outgas, heat resistance, and peelability. The results are shown in Table 1.

[Comparative Example 1]

As the coating liquid, a temperature-sensitive adhesive sheet having a thickness of 40 µm was obtained in the same manner as in Example 1 described above except that the liquid mixture obtained in Comparative Synthesis Example 1 was used.

About the obtained temperature-sensitive adhesive sheet, it carried out similarly to Example 1 mentioned above, and evaluated odor, outgas, heat resistance, and peelability. The results are shown in Table 1.

[Comparative Example 2]

As the coating liquid, a temperature-sensitive adhesive sheet having a thickness of 40 µm was obtained in the same manner as in Example 1 described above except that the liquid mixture obtained in Comparative Synthesis Example 2 was used.

About the obtained temperature-sensitive adhesive sheet, it carried out similarly to Example 1 mentioned above, and evaluated odor, outgas, heat resistance, and peelability. The results are shown in Table 1.

As is clear from Table 1, it is confirmed that all of Examples 1 to 7 are excellent in odor, outgas, heat resistance, and peelability. Further, with respect to Examples 1 to 7, the melting point of the side chain crystalline (meth)acrylic polymer after UV curing was measured by DSC under measurement conditions of 10° C./min. As a result, the melting point of Examples 1 to 7 was 30° C.

On the other hand, Comparative Example 1 in which the ratio of the optical radical initiator is less than 0.2 parts by weight based on 100 parts by weight of the total of the side chain crystalline (meth)acrylic polymer and the (meth)acrylic monomer, the ratio of the optical radical initiator is the side chain crystalline (meth)acryl All of Comparative Example 2, which had more than 1.9 parts by weight based on 100 parts by weight of the polymer and the (meth)acrylic monomer, showed poor odor, outgassing, and heat resistance. In addition, the peelability of Comparative Examples 1 and 2 was capable of peeling without resistance since floatation occurred in the evaluation of heat resistance.

Claims (13)

a substrate in the form of a film;
A pressure-sensitive adhesive layer laminated on one side or both sides of the substrate,
The pressure-sensitive adhesive layer contains at least a side chain crystalline (meth)acrylic polymer, a (meth)acrylic monomer, a polyfunctional (meth)acrylate, and a photoradical initiator, and has ultraviolet curability and is a liquid cured product of a temperature-sensitive adhesive composition is made of,
The melting point of the side chain crystalline (meth)acrylic polymer is 5 to 80 ℃,
The temperature-sensitive adhesive composition contains the photo-radical initiator in a ratio of 0.2 to 1.9 parts by weight with respect to 100 parts by weight of the total of the side chain crystalline (meth)acrylic polymer and the (meth)acrylic monomer,
The pressure-sensitive adhesive layer expresses adhesive strength at a temperature higher than or equal to the melting point of the side chain crystalline (meth)acrylic polymer, and the adhesive strength decreases at a temperature below the melting point. The method of claim 1,
The branched-chain crystalline (meth)acrylic polymer is a polymer that is bulk-polymerized while irradiating with ultraviolet rays after adding a photo-radical initiator to a monomer containing (meth)acrylate having at least a linear alkyl group having 16 or more carbon atoms. 3. The method of claim 1 or 2,
A temperature-sensitive adhesive tape having a weight average molecular weight of 450,000 or more of the side chain crystalline (meth)acrylic polymer. 3. The method of claim 1 or 2,
In the temperature-sensitive adhesive composition, among the side chain crystalline (meth)acrylic polymer, the (meth)acrylic monomer, the polyfunctional (meth)acrylate, and the optical radical initiator, the side chain crystalline (meth)acrylic polymer and the A temperature-sensitive adhesive tape with the highest total content of (meth)acrylic monomers. 3. The method of claim 1 or 2,
The temperature-sensitive adhesive composition contains the side-chain crystalline (meth)acrylic polymer in a ratio of 5 to 40% by weight based on 100% by weight of the total of the side-chain crystalline (meth)acrylic polymer and the (meth)acrylic monomer. tape. 3. The method of claim 1 or 2,
The said polyfunctional (meth)acrylate is a bifunctional (meth)acrylate or a trifunctional (meth)acrylate, and the weight average molecular weight is 200-1,200 thermosensitive adhesive tape. 3. The method of claim 1 or 2,
The temperature-sensitive adhesive composition is a temperature-sensitive adhesive tape that does not contain an organic solvent. delete 3. The method of claim 1 or 2,
The (meth)acrylic monomer is the same as the monomer constituting the side-chain crystalline (meth)acrylic polymer. 3. The method of claim 1 or 2,
When the temperature-sensitive adhesive composition is cured by irradiating an ultraviolet-ray, the irradiation amount of the ultraviolet-ray is 5,000 mJ/cm ² or more. a substrate in the form of a film;
A pressure-sensitive adhesive layer laminated on one side or both sides of the substrate,
The pressure-sensitive adhesive layer contains at least a side chain crystalline (meth)acrylic polymer, a (meth)acrylic monomer, a polyfunctional (meth)acrylate, and a photoradical initiator, and has ultraviolet curability and is a liquid cured product of a temperature-sensitive adhesive composition is made of,
The melting point of the side chain crystalline (meth)acrylic polymer is 5 to 80 ℃,
The temperature-sensitive adhesive composition contains the photo-radical initiator in a ratio of 0.2 to 1.9 parts by weight with respect to 100 parts by weight of the total of the side chain crystalline (meth)acrylic polymer and the (meth)acrylic monomer,
The pressure-sensitive adhesive layer expresses adhesive strength at a temperature higher than or equal to the melting point of the side chain crystalline (meth)acrylic polymer, and the adhesive strength decreases at a temperature below the melting point,
A method for producing a temperature-sensitive adhesive tape, wherein the temperature-sensitive adhesive composition is cured by irradiating an ultraviolet ray of 5,000 mJ/cm ² or more. 12. The method of claim 11,
Method for producing a temperature-sensitive adhesive tape for obtaining the side chain crystalline (meth)acrylic polymer by adding a photoradical initiator to a monomer containing (meth)acrylate having at least a C16 or more linear alkyl group and performing bulk polymerization while irradiating ultraviolet rays . It contains at least a side chain crystalline (meth)acrylic polymer, a (meth)acrylic monomer, a polyfunctional (meth)acrylate, and a photoradical initiator, and consists of a cured product of a liquid temperature-sensitive adhesive composition having UV curability and liquid,
The melting point of the side chain crystalline (meth)acrylic polymer is 5 to 80 ℃,
The temperature-sensitive adhesive composition contains the photo-radical initiator in a proportion of 0.2 to 1.9 parts by weight based on 100 parts by weight of the total of the side chain crystalline (meth)acrylic polymer and the (meth)acrylic monomer,
A temperature-sensitive adhesive sheet that expresses adhesive strength at a temperature higher than or equal to the melting point of the side chain crystalline (meth)acrylic polymer, and lowers the adhesive strength at a temperature below the melting point.