KR20180088918A - Double-sided adhesive sheet - Google Patents

Abstract

Sensitive adhesive sheet having a first pressure-sensitive adhesive layer and a second pressure-sensitive adhesive layer on both sides of a support, wherein the support comprises polylactic acid and the support has a thickness of 1.5 m or less. The double-sided pressure-sensitive adhesive sheet can exhibit a sufficiently high adhesive force even when it is made thin, and is excellent in the effect of suppressing the residual pressure-sensitive adhesive.

Description

Double-sided adhesive sheet

The present invention relates to a double-sided pressure-sensitive adhesive sheet.

The adhesive force of the pressure-sensitive adhesive sheet depends on the application amount of the pressure-sensitive adhesive on the support, that is, the thickness of the pressure-sensitive adhesive layer to be formed, in addition to the composition and polarity of the pressure- That is, in general, the adhesive force of the pressure-sensitive adhesive sheet becomes higher as the pressure-sensitive adhesive layer is thicker.

The thickness of the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet such as a label and a tape is appropriately set in accordance with the use of the pressure-sensitive adhesive sheet, but the thickness of the pressure-sensitive adhesive sheet is not made thinner than 10 占 퐉.

However, in recent years, it has been desired to reduce the thickness of electronic apparatuses, optical apparatuses, and the like, and adhesive sheets used for joining members of such electronic apparatuses and optical apparatuses, or for temporary bonding at the time of processing, Is required.

In order to cope with such a demand, various pressure-sensitive adhesive sheets have been proposed.

For example, Patent Document 1 discloses a pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer on both sides of a support such as a polyethylene terephthalate (PET) film having a thickness of 0.002 to 0.012 mm, a total thickness of 0.003 mm or more and less than 0.03 mm, A double-sided adhesive tape having a width of 26 MPa / 10 mm is disclosed.

Japanese Patent Application Laid-Open No. 2005-105212

However, there are cases where two members of a thinned electronic apparatus, an optical apparatus, and the like are bonded together via a double-sided pressure-sensitive adhesive sheet. In order to respond to the requirement for thinning of the apparatus, the clearance between the two members to be bonded is often narrow. Therefore, the double-sided pressure-sensitive adhesive sheet used for bonding requires further thinning.

As means for coping with the requirement for further thinning of the double-sided pressure-sensitive adhesive sheet, it is possible to reduce the thickness of each layer such as a pressure-sensitive adhesive layer and a support constituting the double-sided pressure-sensitive adhesive sheet.

However, when the pressure-sensitive adhesive layer is further made thinner, the adhesive force is lowered, and it is feared that the joining of the two members becomes insufficient.

On the other hand, the thinning of the support has a limitation in terms of the production of the support and the strength thereof. For example, in the double-sided adhesive sheet described in Patent Document 1, it is very difficult from the viewpoint of molding to make the thickness of the PET film used as the support less than 2 탆.

As a means for reducing the thickness of the double-sided pressure-sensitive adhesive sheet, there is also a method of reducing the thickness of the support (core) by using a double-sided pressure-sensitive adhesive sheet having a structure in which the pressure- I can think.

However, when the support (core material) is omitted, when one of the two release materials is peeled off, the release material is not removed from the predetermined interface to be originally peeled off, so that the pressure-sensitive adhesive layer is cohesively broken, Quot; adhesive remnant phenomenon " in which a part of the pressure-sensitive adhesive layer remains and remains.

In addition, in Patent Document 1, no study has been made to avoid additional thinning while maintaining the adhesive strength of the double-sided pressure-sensitive adhesive sheet and to avoid "adhesive remnant phenomenon" accompanying thinning of the pressure-sensitive adhesive layer.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and it is an object of the present invention to provide a double-sided pressure-sensitive adhesive sheet which can exhibit a sufficiently high adhesive force even when it is made thin, and is excellent in suppressing the residual phenomenon of a pressure-sensitive adhesive.

The present inventors have found that the above problems can be solved by using a support containing polylactic acid and adjusting the thickness of the support to a predetermined value or less in a double-sided pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer on both sides of the support .

That is, the present invention provides the following [1] to [8].

[1] A double-sided pressure-sensitive adhesive sheet having a first pressure-sensitive adhesive layer and a second pressure-sensitive adhesive layer on both sides of a support,

Wherein the support comprises polylactic acid and the support has a thickness of 1.5 m or less.

[2] The double-sided pressure-sensitive adhesive sheet according to [1], wherein the support has a film strength of 1 to 300 mN.

[3] The double-faced pressure-sensitive adhesive sheet according to the above [1] or [2], wherein the content of the polylactic acid is 70 to 100 mass% with respect to the total mass of the support.

[4] The double-sided pressure-sensitive adhesive sheet according to any one of [1] to [3], wherein at least one of the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer is a layer formed of an acrylic pressure-sensitive adhesive containing an acrylic resin.

[5] The double-faced pressure-sensitive adhesive sheet according to any one of [1] to [4], wherein the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer each independently have a thickness of 0.5 to 3.0 μm.

[6] The double-faced pressure-sensitive adhesive sheet according to any one of [1] to [5], wherein the ratio of the thickness of the support to the total thickness of 100 of the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer is 5.0 to 70.0.

[7] A double-faced pressure-sensitive adhesive sheet as described in any one of [1] to [6], wherein the total thickness of the double-faced pressure-sensitive adhesive sheet when the double-faced pressure-sensitive adhesive sheet is applied to two adherends via the double-faced pressure-sensitive adhesive sheet is 6.0 μm or less.

[8] Adhesive strength measured according to JIS Z 0237: 2000 after 24 hours from being stuck to a stainless steel plate (SUS 304 steel plate, 120 polish) in an environment of 23 ° C. and 50% RH (relative humidity) Sensitive adhesive sheet according to any one of [1] to [7] above,

The double-sided pressure-sensitive adhesive sheet of the present invention can exhibit a sufficiently high adhesive force even when it is made thin, and is excellent in the effect of suppressing the pressure-sensitive adhesive residue phenomenon.

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a cross-sectional view of a double-sided pressure-sensitive adhesive sheet according to an embodiment of the present invention, showing the structure of a double-sided pressure-sensitive adhesive sheet;

In the present specification, the thicknesses of the respective layers constituting the double-sided pressure-sensitive adhesive sheet and the total thickness of the double-sided pressure-sensitive adhesive sheet are values measured by spectroscopic analysis of reflected light, specifically, values measured based on the methods described in the Examples it means.

In the present specification, the value of the mass average molecular weight (Mw) is a value in terms of standard polystyrene measured by gel permeation chromatography (GPC), specifically, a value measured based on the method described in the Examples do.

In the present specification, for example, " (meth) acrylate " refers to both acrylate and methacrylate, and other similar terms are also applicable.

[Composition of double-faced pressure-sensitive adhesive sheet]

The double-sided pressure-sensitive adhesive sheet of the present invention is not particularly limited as long as it has a first pressure-sensitive adhesive layer and a second pressure-sensitive adhesive layer (hereinafter collectively referred to as "pressure-sensitive adhesive layer") on both surfaces of the support.

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a cross-sectional view of a double-sided pressure-sensitive adhesive sheet according to an embodiment of the present invention, showing the structure of a double-sided pressure-sensitive adhesive sheet;

The double-sided pressure-sensitive adhesive sheet according to one embodiment of the present invention includes a first pressure-sensitive adhesive layer 12a and a second pressure-sensitive adhesive layer 12b on both sides of a support 11 as shown in Fig. 1 (a) Sensitive adhesive sheet 1 having a structure in which the pressure-sensitive adhesive sheet 1 is directly laminated.

In addition, from the viewpoint of handling property, as shown in Fig. 1 (b), the peeling members 13a and 13b are further laminated on the surfaces of the first pressure-sensitive adhesive layer 12a and the second pressure-sensitive adhesive layer 12b, respectively Sensitive adhesive sheet 2 may be used.

In the double-sided pressure-sensitive adhesive sheet of one embodiment of the present invention, on both surfaces of the first pressure-sensitive adhesive layer 12a and the second pressure-sensitive adhesive layer 12b, a release material having been subjected to the release treatment is laminated, It may be a double-sided pressure-sensitive adhesive sheet having a wound configuration.

In short, the double-sided pressure-sensitive adhesive sheet of one embodiment of the present invention may be configured such that a release material is further laminated on one or both surfaces of the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer.

The total thickness of the double-faced pressure-sensitive adhesive sheet when the double-faced pressure-sensitive adhesive sheet is applied to two adherends via the double-faced pressure-sensitive adhesive sheet of the present invention is preferably a double-faced pressure-sensitive adhesive sheet which can be used for bonding two narrow- Is preferably 6.0 占 퐉 or less, more preferably 5.0 占 퐉 or less, still more preferably 4.0 占 퐉 or less, still more preferably 3.5 占 퐉 or less, particularly preferably 3.0 占 퐉 or less.

The double-sided pressure-sensitive adhesive sheet of the present invention can exhibit a sufficiently high adhesive force even when the pressure-sensitive adhesive sheet is thinned to 6.0 탆 or less, and can effectively suppress the residual pressure-sensitive adhesive.

On the other hand, from the viewpoint of exhibiting an excellent adhesive force and also being capable of effectively suppressing the residual adhesive phenomenon, the double-faced pressure-sensitive adhesive sheet of the present invention, when affixed to two adherends via the double- The total thickness is preferably at least 1.5 탆, more preferably at least 1.7 탆, even more preferably at least 2.0 탆.

In the present specification, the term " thinned double-faced pressure-sensitive adhesive sheet " means a double-faced pressure-sensitive adhesive sheet in which the total thickness of the double-faced pressure-sensitive adhesive sheet when affixed to two adherends via a double-faced pressure-sensitive adhesive sheet is adjusted to 6.0 m or less .

In addition, in the present specification, the "total thickness of the double-sided pressure-sensitive adhesive sheet when sticking to two adherends with the double-sided pressure-sensitive adhesive sheet interposed therebetween" refers to the total thickness of the pressure- Quot; Z1 " in the double-sided adhesive sheet 1 shown in Fig. 1 and " Z2 " in the double-sided adhesive sheet 2, for example.

In other words, the total thickness of the double-sided pressure-sensitive adhesive sheet when the double-sided pressure-sensitive adhesive sheet 2 is bonded to two adherends via the double-sided pressure-sensitive adhesive sheet is not limited to the total thickness of the double-sided pressure-sensitive adhesive sheet 2 shown in Fig. Thickness is not included, but includes, for example, the thickness of the support and the layer other than the pressure-sensitive adhesive layer which are not removed even when attached to the adherend.

Examples of the layer other than the support and the pressure-sensitive adhesive layer that are not removed even when adhered to an adherend include a primer layer, an antistatic layer, and an ultraviolet absorbing layer. 2 pressure-sensitive adhesive layer.

In the double-sided pressure-sensitive adhesive sheet of one embodiment of the present invention, the ratio of the thickness of the support to the total thickness of 100 of the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer is preferably 5.0 to 70.0, more preferably 5.2 to 50.0, More preferably 5.5 to 40.0, even more preferably 6.0 to 30.0, and particularly preferably 6.2 to 20.0.

When the ratio is within the above range, a double-sided pressure-sensitive adhesive sheet capable of exhibiting excellent adhesive force and effectively restraining the residual adhesive phenomenon can be obtained. In addition, tearing of the double-sided pressure-sensitive adhesive sheet, which is likely to occur during bonding or peeling, can be suppressed.

Hereinafter, the details of the support, the pressure-sensitive adhesive layer (first and second pressure-sensitive adhesive layers), and the release material constituting the double-sided pressure-sensitive adhesive sheet of one embodiment of the present invention will be described.

<Support>

The support of the double-faced pressure-sensitive adhesive sheet of the present invention comprises polylactic acid and has a thickness of 1.5 탆 or less.

It is difficult to form a general-purpose resin such as polyethylene terephthalate (PET) or polyurethane, which is a constituent resin of a support used in a general adhesive sheet, to a thickness of 1.5 mu m or less by a usual molding method.

Even if a support having a thickness of 1.5 占 퐉 or less is obtained by using a general-purpose resin such as PET or polyurethane by a special molding method, the effect of improving the adhesive strength is not exhibited by using the support.

On the other hand, since the support containing polylactic acid has high self-supporting property, it is possible to form the support to a thickness of 1.5 탆 or less.

The inventors of the present invention have found that a double-sided pressure-sensitive adhesive sheet in which a pressure-sensitive adhesive layer is formed on both surfaces of a support containing polylactic acid has a very high effect of improving the adhesive force and can exhibit a high adhesive force, Based on the knowledge, the double-sided pressure-sensitive adhesive sheet of the present invention is completed.

In particular, even when the support containing polylactic acid is made thinner to 1.5 占 퐉 or less in thickness, it has high self-supportability and suitable flexibility.

Therefore, the double-sided pressure-sensitive adhesive sheet in which the pressure-sensitive adhesive layer formed on both sides of the support is formed has superior followability to the surface of the adherend at the time of affixing the adherend, and even when the pressure- .

In a double-sided pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer on both sides of a support such as a general PET film, two pressure-sensitive adhesive layers are divided by a support so that the pressure-sensitive adhesive force of the other pressure- It is hard to think.

In short, the adhesive force of each pressure sensitive adhesive layer is basically influenced only by the constitution and the characteristic of each pressure sensitive adhesive layer, and the influence exerted by the constitution and the characteristic of the other pressure sensitive adhesive layer is very small.

On the other hand, in the double-sided pressure-sensitive adhesive sheet of the present invention, since the support containing polylactic acid is thinned to 1.5 m or less, for example, due to the flexibility and other properties of one pressure- It is possible to contribute to the improvement of the adhesive force of the pressure-sensitive adhesive layer.

As a result, the double-sided pressure-sensitive adhesive sheet of the present invention is considered to exhibit excellent adhesive force on both surfaces even when it is made into a thin film.

Further, since the double-sided pressure-sensitive adhesive sheet of the present invention has a support as a constitution, the pressure-sensitive adhesive remnant phenomenon can be effectively suppressed.

The thickness of the support used in the present invention is 1.5 占 퐉 or less, preferably 1.2 占 퐉 or less, more preferably 1.0 占 퐉 or less, still more preferably 0.8 占 퐉 or less, still more preferably 0.6 占 퐉 or less, 0.4 탆 or less.

The double-sided pressure-sensitive adhesive sheet using a support having a thickness of more than 1.5 占 퐉 tends to have poor supportability to the surface of the adherend because the support itself is hard, and as a result, the adhesive strength tends to decrease.

From the viewpoint of providing a double-sided pressure-sensitive adhesive sheet capable of effectively suppressing the residual pressure-sensitive adhesive property and suppressing the breakage of the pressure-sensitive adhesive double-faced sheet which may occur during bonding or peeling, Preferably 0.01 mu m or more, more preferably 0.05 mu m or more, and further preferably 0.10 mu m or more.

In the present invention, "polylactic acid" refers to a polymer having the structural unit (1) represented by the following formula (I), and the polymer may have a structural unit other than the structural unit (1).

[Chemical Formula 1]

The structural unit (1) may be a structural unit derived from L-lactic acid or a structural unit derived from D-lactic acid.

In short, the polylactic acid may be poly-L-lactic acid which is a homopolymer of L-lactic acid, poly-D-lactic acid which is a homopolymer of D-lactic acid, or a copolymer of L-lactic acid and D-lactic acid.

Of these, polylactic acid is preferably a copolymer of L-lactic acid and D-lactic acid.

When a copolymer of L-lactic acid and D-lactic acid is used, the molar ratio ([L-lactic acid] / [L-lactic acid]) of the constitutional unit derived from L-lactic acid and the constitutional unit derived from D- [D-lactic acid]) is preferably 10/90 to 90/10, more preferably 20/80 to 80/20, still more preferably 30/70 to 70/30, still more preferably 40/60 ~ 60/40.

By making the copolymer having the molar ratio within the above range, the crystallinity can be appropriately maintained, and the support containing the copolymer can be adjusted to have an appropriate hardness. As a result, when the obtained pressure-sensitive adhesive sheet is attached to an adherend, excellent adherence to the surface of adherend is obtained, and excellent adhesive force is easily produced.

The mass average molecular weight (Mw) of polylactic acid is preferably 20,000 to 500,000, more preferably 50,000 to 400,000, and even more preferably 70,000 to 300,000.

The support used in one embodiment of the present invention may contain a resin other than polylactic acid, an additive, and the like within a range that does not impair the effect of the present invention.

Examples of the resin other than polylactic acid that can be contained in the support include polyester resins such as polyethylene terephthalate, polybutylene terephthalate and polyethylene naphthalate, urethane resins such as urethane acrylate, polyethylene resins, A polyvinyl chloride resin, a polyvinyl alcohol resin, an ethylene-vinyl acetate copolymer, a polystyrene resin, a polycarbonate resin, an acrylic resin, a norbornene resin, a cycloolefin resin, a polypropylene resin, a polyvinyl chloride resin, a polyvinylidene chloride resin, Resins and the like.

Examples of the additive that can be contained in the support include an ultraviolet absorber, a light stabilizer, an antioxidant, an antistatic agent, a slip agent, an anti-blocking agent, a colorant and the like.

The support used in one embodiment of the present invention may be any one containing polylactic acid. For example, it is possible to use not only a support obtained by molding a resin composition containing polylactic acid but also a resin other than polylactic acid, Or the like may be laminated with a resin composition containing polylactic acid, or the like.

However, from the viewpoint of producing a support having a thickness of 1.5 탆 or less, the support used in one embodiment of the present invention is preferably a single-layer support formed by molding a resin composition containing polylactic acid.

The resin composition may contain a resin component other than polylactic acid and various additives insofar as the effect of the present invention is not impaired.

The content of the polylactic acid contained in the support used in one embodiment of the present invention is preferably in the range of from the viewpoint of forming a double-sided pressure-sensitive adhesive sheet capable of exhibiting a sufficiently high adhesive force even when it is made thinner and in view of producing a support having a thickness of 1.5 m or less Is preferably 70 to 100 mass%, more preferably 80 to 100 mass%, still more preferably 90 to 100 mass%, still more preferably 95 to 100 mass%, relative to the total mass (100 mass%) of the support. to be.

In particular, the content of the copolymer of L-lactic acid and D-lactic acid contained in the support used in one embodiment of the present invention is preferably 60 to 100 mass% with respect to the total mass (100 mass%) of the support, , More preferably 70 to 100 mass%, further preferably 80 to 100 mass%, still more preferably 90 to 100 mass%, and particularly preferably 95 to 100 mass%.

The film strength of the support used in one embodiment of the present invention is preferably from 1 to 300 mN, more preferably from 3 to 250 mN, more preferably from 3 to 250 mN, from the viewpoint of forming a double-sided pressure- More preferably 5 to 200 mN, still more preferably 10 to 130 mN, particularly preferably 15 to 90 mN.

Even when the double-sided pressure-sensitive adhesive sheet in which the pressure-sensitive adhesive layer formed into a thin film is formed on both sides of the support has a membrane strength of the support within the above-mentioned range, excellent adherence to the surface of the adherend upon adhesion to the adherend, The adhesive force is likely to be developed.

In the present specification, the film strength of the support is a value measured in accordance with JIS Z 1707 (1997), specifically, a value measured based on the method and conditions described in the examples.

&Lt; First pressure-sensitive adhesive layer and second pressure-sensitive adhesive layer &gt;

The double-sided pressure-sensitive adhesive sheet of the present invention has a first pressure-sensitive adhesive layer and a second pressure-sensitive adhesive layer on both sides of a support.

The thickness of each of the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer is preferably 0.5 to 3.0 탆, more preferably 0.7 to 2.0 탆, still more preferably 0.8 to 1.8 탆, still more preferably, 0.9 to 1.6 mu m.

Sensitive adhesive sheet of the present invention comprises a polylactic acid and a support having a thickness of not more than 1.5 mu m so that even when the thickness of each pressure-sensitive adhesive layer is reduced to 3.0 mu m or less, .

The total thickness of the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer is preferably 1.0 to 6.0 占 퐉, more preferably 1.4 to 4.0 占 퐉, still more preferably 1.6 to 3.6 占 퐉, still more preferably 1.8 to 3.6 占 퐉, 3.2 탆.

The pressure-sensitive adhesive that is a material for forming the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer is not particularly limited as long as it can exhibit a sufficiently high adhesive force even if the pressure-sensitive adhesive layer is made thin, and examples thereof include acrylic resins, urethane- A pressure sensitive adhesive containing at least one adhesive resin selected from a silicone resin, a vinyl ether resin, a polyester resin, and a polyolefin resin.

However, from the viewpoint of enabling a sufficiently high adhesive force to be maintained regardless of the environment, the adhesive resin is preferably an ultraviolet light curable resin.

In the present specification, ultraviolet noncurable resin means a resin having no polymerizable functional group that can be polymerized by irradiation with ultraviolet rays.

The pressure-sensitive adhesive may be used in the range of not impairing the effect of the present invention, for example, a crosslinking agent, a tackifier, an ultraviolet absorber, an antioxidant, a preservative, a fungicide, a plasticizer, Of an additive for a pressure-sensitive adhesive.

However, the content of the oligomer component having a polymerizable functional group in the pressure-sensitive adhesive is preferably as small as possible from the viewpoint of enabling a sufficiently high adhesive force to be maintained regardless of the environment.

The content of the oligomer component having a polymerizable functional group is preferably less than 5 parts by mass, more preferably less than 1 part by mass, more preferably less than 0.01 parts by mass, further preferably less than 0.01 parts by mass, relative to 100 parts by mass of the adhesive resin contained in the pressure- It is preferably less than 0.001 part by mass.

The pressure-sensitive adhesive layer is formed by applying a pressure-sensitive adhesive on a support or a release member. However, in order to easily form a pressure-sensitive adhesive layer having a small thickness, the pressure-sensitive adhesive may be diluted with an organic solvent to form a solution of the pressure-sensitive adhesive.

As the organic solvent, for example, toluene, ethyl acetate, methyl ethyl ketone and the like can be mentioned, but the organic solvent used in the synthesis of the resin contained in the pressure-sensitive adhesive layer may be used as it is.

The solid content concentration of the solution of the pressure-sensitive adhesive is preferably 5 to 60 mass%, more preferably 10 to 40 mass%.

In the double-sided pressure-sensitive adhesive sheet of the present invention, at least one of the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer is preferably an acrylic pressure-sensitive adhesive containing an acrylic resin , And it is more preferable that both the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer are layers formed of the acrylic pressure-sensitive adhesive.

The acrylic pressure-sensitive adhesive is preferably an ultraviolet-ray non-curing acrylic pressure-sensitive adhesive from the viewpoint of making it possible to maintain a sufficiently high adhesive force even if the pressure-sensitive adhesive layer to be formed is thinned.

In short, the acrylic resin contained in the pressure-sensitive adhesive is preferably an ultraviolet non-curable acrylic resin.

As the acrylic pressure sensitive adhesive to be used in one embodiment of the present invention, it is preferable to use, as an acrylic resin, an acrylic pressure sensitive adhesive which is derived from an alkyl (meth) acrylate having an alkyl group having 1 to 20 carbon atoms (A) having a structural unit (a1) derived from a functional group-containing monomer and a structural unit (a2) derived from a functional group-containing monomer.

The acrylic pressure-sensitive adhesive preferably contains a crosslinking agent (B) together with the acrylic copolymer (A), and may contain the above-described pressure-sensitive adhesive additive within the range not hindering the effect of the present invention.

Hereinafter, the acrylic copolymer (A) and the crosslinking agent (B) which are included in the acrylic pressure-sensitive adhesive which is preferable as a pressure-sensitive adhesive which is a material for forming the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer will be described.

(Acrylic copolymer (A))

The acrylic copolymer (A) contains a structural unit (a1) derived from an alkyl (meth) acrylate having an alkyl group having 1 to 20 carbon atoms (hereinafter also referred to as "monomer (a1 ')" (A2 ') derived from a monomer (a2').

The acrylic copolymer (A) has the structural unit (a3) derived from the monomer (a3 ') other than the monomer (a1') and the monomer (a1 ') together with the structural units (a1) and .

The form of copolymerization of the acrylic copolymer (A1) is not particularly limited, and any of block copolymer, random copolymer and graft copolymer may be used.

The acrylic copolymer (A) may be used alone or in combination of two or more.

However, the acrylic copolymer (A1) is preferably an ultraviolet non-curable acrylic copolymer having no polymerizable functional group.

The number of carbon atoms of the alkyl group of the monomer (a1 ') is preferably from 1 to 16, more preferably from 1 to 12, still more preferably from 4 to 8, still more preferably from 4 to 6.

Examples of the monomer (a1 ') include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (Meth) acrylate, n-pentyl (meth) acrylate, n-hexyl (meth) acrylate, n-heptyl Acrylate, lauryl (meth) acrylate, tridecyl (meth) acrylate, and stearyl (meth) acrylate.

These monomers (a1 ') may be used alone or in combination of two or more.

In one embodiment of the present invention, as the monomer (a1 '), n-butyl (meth) acrylate and 2-ethylhexyl (meth) acrylate are preferable, and n-butyl (meth) acrylate is more preferable.

The content of the constituent unit (a1) is preferably 50 to 98 mol%, more preferably 60 to 97 mol%, more preferably 60 to 99 mol%, based on the entire constituent unit (100 mol%) of the acrylic copolymer (A) 70 to 96 mol%, and even more preferably 80 to 93 mol%.

Examples of the monomer (a2 ') include a hydroxyl group-containing monomer, a carboxyl group-containing monomer, an epoxy group-containing monomer, an amino group-containing monomer, a cyano group-containing monomer, a keto group-containing monomer and an alkoxysilyl group- .

These monomers (a2 ') may be used alone or in combination of two or more.

In one embodiment of the present invention, the monomer (a2 ') is preferably a carboxyl group-containing monomer.

Examples of the carboxyl group-containing monomer include (meth) acrylic acid, succinic acid, maleic acid, fumaric acid, itaconic acid and derivatives thereof, -Acryloyloxyethyl) and 2-carboxyethyl acrylate are more preferable.

The content of the constituent unit (a2) is preferably from 2 to 50 mol%, more preferably from 3 to 40 mol%, more preferably from 3 to 40 mol%, based on the entire constituent unit (100 mol%) of the acrylic copolymer (A) 4 to 30 mol%, and still more preferably 7 to 20 mol%.

In one embodiment of the present invention, the acrylic copolymer (A) is a copolymer comprising a structural unit (a2) derived from any of mono (2-acryloyloxyethyl) succinate and 2-carboxyethyl acrylate, 1).

The content of the constituent unit (a2-1) in the constituent unit (a2) is preferably 60 to 100 mol%, more preferably 70 to 100 mol% with respect to the total amount (100 mol%) of the constituent unit (a2) Mol%, more preferably 80 to 100 mol%, still more preferably 90 to 100 mol%, particularly preferably 100 mol%.

The content of the structural unit (a2-1) is preferably from 2 to 45 mol%, more preferably from 3 to 35 mol%, more preferably from 3 to 35 mol% based on the total structural units (100 mol%) of the acrylic copolymer (A) , More preferably 4 to 25 mol%, and still more preferably 7 to 20 mol%.

The monomer (a3 ') includes, for example, cyclohexyl (meth) acrylate, benzyl (meth) acrylate, isobornyl (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentenyl (Meth) acrylate, vinyl acetate, acrylonitrile, and styrene having a cyclic structure such as acrylate, dicyclopentenyloxyethyl (meth) acrylate and imide (meth) acrylate.

These monomers (a3 ') may be used alone or in combination of two or more.

The content of the constituent unit (a3) is preferably 0 to 20 mol%, more preferably 0 to 10 mol%, and even more preferably 0 to 10 mol%, relative to the total constituent units (100 wt%) of the acrylic copolymer (A) 0 to 5 mol%, and still more preferably 0 to 1 mol%.

The mass average molecular weight (Mw) of the acrylic copolymer (A) is preferably 50,000 to 1,500,000, more preferably 1,500 to 1,300,000, still more preferably 2,500 to 1,100,000, still more preferably 35 It is only ~ 90 million.

The content of the acrylic copolymer (A) in the acrylic pressure-sensitive adhesive to be used in one embodiment of the present invention is preferably 50 to 100% by mass, more preferably 50 to 100% by mass with respect to the total amount (100 mass%) of the effective components of the acrylic pressure- By mass, more preferably from 70 to 99.90% by mass, still more preferably from 80 to 99.00% by mass, and particularly preferably from 90 to 98% by mass.

In addition, the acrylic pressure-sensitive adhesive used in an embodiment of the present invention may contain a pressure-sensitive adhesive resin other than the acrylic copolymer (A).

The content of the adhesive resin other than the acrylic copolymer (A) is preferably 0 to 100 parts by mass, more preferably 0 to 60 parts by mass, relative to 100 parts by mass of the acrylic copolymer (A) contained in the acrylic pressure- More preferably 0 to 30 parts by mass, still more preferably 0 to 15 parts by mass, and particularly preferably 0 to 10 parts by mass.

(Crosslinking agent (B))

The acrylic pressure-sensitive adhesive used in an embodiment of the present invention preferably contains a cross-linking agent (B) together with the acrylic copolymer (A).

Examples of the crosslinking agent (B) include an isocyanate crosslinking agent, an epoxy crosslinking agent, an aziridine crosslinking agent, a metal chelating crosslinking agent, an amine crosslinking agent and an amino resin crosslinking agent.

These crosslinking agents (B) may be used alone or in combination of two or more.

In one aspect of the present invention, it is preferable that the cross-linking agent (B) includes an isocyanate-based cross-linking agent from the viewpoint of exhibiting a sufficiently high adhesive force even in a thin pressure-sensitive adhesive layer.

The content of the crosslinking agent (B) in the acrylic pressure-sensitive adhesive used in an embodiment of the present invention is preferably 0.01 to 8 parts by mass, more preferably 0.05 to 5 parts by mass, more preferably 0.05 to 5 parts by mass, per 100 parts by mass of the acrylic copolymer (A) More preferably 0.1 to 3 parts by mass.

<Release material>

The double-sided pressure-sensitive adhesive sheet of one embodiment of the present invention preferably has a structure in which a release material is further laminated on at least one surface of the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer.

Since the double-faced pressure-sensitive adhesive sheet of the present invention has a support containing polylactic acid, when the pressure-sensitive adhesive sheet is of the same construction as the double-faced pressure-sensitive adhesive sheet 2 shown in Fig. 1 (b) The residual adhesive phenomenon can be effectively suppressed.

The release material to be used is not particularly limited, but from the viewpoint of ease of handling, a release sheet coated with a release agent on a substrate is preferable. The release sheet may be a release sheet coated with a release agent on both sides of the substrate, or a release agent applied to only one side of the substrate and subjected to release treatment.

Examples of the substrate for peeling include a paper substrate such as a gloss paper, a coat paper, or a cast coat paper; A laminate paper in which a thermoplastic resin such as polyethylene is laminated on these paper base materials; Further, a plastic film such as a polyester film such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate, and a polyolefin film such as polypropylene or polyethylene can be used.

Examples of the releasing agent include a releasing agent comprising a resin such as a rubber-based elastomer such as an olefin resin, an isoprene resin, and a butadiene resin, a long chain alkyl resin, an alkyd resin, a fluorine resin or a silicone resin .

In the case of using two release materials 13a and 13b as in the double-sided pressure-sensitive adhesive sheet 2 shown in Fig. 1 (b), the release materials 13a and 13b may be the same or different from each other May be used. However, the difference in the peeling force between the peeling member 13a and the peeling member 13b is adjusted so that the peeling member (heavy member) having a large peeling force and the peeling member (light peeling member) having a weaker peeling force It is preferable to use two kinds of materials.

In the case of using a peeling material on both sides of which a peeling agent has been applied and peeled, it is preferable that the peeling force of the peeling material is adjusted so that the difference in peeling force is different.

The thickness of the release sheet is not particularly limited and is appropriately selected, and is usually 10 to 200 占 퐉, preferably 25 to 150 占 퐉, more preferably 35 to 80 占 퐉.

[Method for producing double-faced pressure-sensitive adhesive sheet]

The method of producing the double-sided pressure-sensitive adhesive sheet of the present invention is not particularly limited.

For example, in the case of the double-sided pressure-sensitive adhesive sheet 1 of Fig. 1 (a), after the first pressure-sensitive adhesive layer 12a is formed by applying a pressure-sensitive adhesive on one side of the support 11, 11 can be formed by applying a pressure-sensitive adhesive on the other surface and drying the same to form a second pressure-sensitive adhesive layer 12b.

The double-faced pressure-sensitive adhesive sheet 2 of Fig. 1 (b) can be produced in the following sequence (ia) to (iiia).

(ia) A first adhesive layer 12a is formed by applying a pressure-sensitive adhesive on the surface of the release material 13a on which the release material has been removed, and drying the pressure-sensitive adhesive layer 12a to bond the support 11, And make them.

(iia) A second pressure-sensitive adhesive layer 12b is formed by applying a pressure-sensitive adhesive on the surface of the exfoliated stripper 13b, which is separately prepared, and drying the same.

(iiia) The surface of the support 11 of the single-sided pressure-sensitive adhesive sheet produced in (ia) and the surface exposed by the second pressure-sensitive adhesive layer 12b formed in (iia) 2).

The method for producing the double-faced pressure-sensitive adhesive sheet 2 of Fig. 1 (b) may also be produced in the following order (ib) to (iiib).

(ib) A first adhesive layer 12a is formed by applying a pressure-sensitive adhesive on the surface to which the release treatment of the release material 13a has been applied and drying it.

(iib) A second pressure-sensitive adhesive layer 12b is formed by applying a pressure-sensitive adhesive in the same manner on the surface of the exfoliated stripper 13b.

(iiib) The surface on which the first pressure-sensitive adhesive layer 12a is exposed and the surface on which the second pressure-sensitive adhesive layer 12b is exposed are adhered to both surfaces of the support 11 to obtain a pressure-sensitive adhesive double coated sheet 2 .

In the above-described method for producing a double-sided pressure-sensitive adhesive sheet, since the supporting member 11 to be used is very thin, an application sheet may be used in order to improve the handling property of the supporting member 11. [

In this specification, &quot; application sheet &quot; means a sheet which is pasted to support the core material or the pressure sensitive adhesive sheet in order to improve handling properties of a very thin core material or pressure sensitive adhesive sheet to such an extent that conveyance or adherence becomes difficult.

In the production process of the double-sided pressure-sensitive adhesive sheet, the application sheet is laminated on the support 11 in a state of being laminated with the pressure-sensitive adhesive layer, and thereafter the application sheet is peeled off. On the surface of the support 11 after separation, The pressure sensitive adhesive layer of one side may be laminated to produce a pressure sensitive adhesive double coated sheet.

In addition, when the pressure-sensitive adhesive is applied to the support or the release member, it is preferable to dilute the pressure-sensitive adhesive with an organic solvent to form a solution of the pressure-sensitive adhesive, as described above, in order to easily form a pressure-sensitive adhesive layer having a small thickness.

Examples of the method for applying the pressure-sensitive adhesive on the support or on the release material include a spin coat method, a spray coat method, a bar coat method, a knife coat method, a roll coat method, a blade coat method, a die coat method, And the like.

In the case where a crosslinking agent is blended, a coating film is formed by applying a pressure-sensitive adhesive on a support or a peeling member in order to promote cross-linking (reaction) and promote tackiness, It is preferable to carry out the treatment.

The temperature condition of the heat treatment is preferably 70 to 150 占 폚, more preferably 80 to 120 占 폚. The treatment time for the heat treatment is preferably 30 seconds to 5 minutes, more preferably 40 to 180 seconds.

[Property of double-faced pressure-sensitive adhesive sheet]

The double-sided pressure-sensitive adhesive sheet of the present invention can exhibit a sufficiently high adhesive force even when it is made thin, and is excellent in the effect of suppressing the pressure-sensitive adhesive residue phenomenon.

The double-sided pressure-sensitive adhesive sheet of one embodiment of the present invention was applied to a stainless steel plate (SUS 304 steel plate, 120 polish) under an environment of 23 ° C and 50% RH (relative humidity) The adhesive strength measured according to the above criteria is preferably 1.5 N / 25 mm or more, more preferably 2.0 N / 25 mm or more, further preferably 2.5 N / 25 mm or more, still more preferably 3.0 N / 25 mm or more , And particularly preferably 4.5 N / 25 mm or more.

In the present specification, the adhesive force refers to a value measured in accordance with JIS Z 0237: 2000, specifically, a value measured under the methods and conditions described in the following examples.

Example

The various physical properties shown in the description of the following examples are values measured as follows.

(1) Mass average molecular weight (Mw)

Measured by the following apparatus and conditions, and calculated in terms of standard polystyrene.

Device name: &quot; HLC-8220GPC &quot; (manufactured by Tosoh Corporation)

Column: "TSKgelGMHXL", "TSKgelGMHXL" and "TSKgel2000HXL" (all manufactured by Tosoh Corporation) were connected in sequence

Developing solvent: tetrahydrofuran

Injection amount: 80 μl

Measuring temperature: 40 ° C

Flow rate: 1.0 ml / min

Detector: differential refractometer

(2) Thickness measurement

The thickness and the total thickness of each layer of the double-sided pressure-sensitive adhesive sheet were measured with a reflective film thickness meter (product name: "F20" manufactured by Philmetrix Co., Ltd.).

Specifically, the film thickness at seven arbitrary points on the double-faced pressure-sensitive adhesive sheet cut into 10 mm x 100 mm was measured using the above reflective film thickness meter, and the value of the film thickness at seven points The average value of the film thickness values at five points excluding the maximum value and the minimum value was calculated and the average value was set as the thickness or the total thickness of each layer of the double-faced pressure-sensitive adhesive sheet to be measured.

(3) Film strength of the support

Measured according to JIS Z 1707 (1997).

Specifically, a semicircular needle having a diameter of 1.0 mm and a tip radius of 0.5 mm was cut at a speed of 30 mm / min by a creep meter (RE2-33005B, manufactured by Yamaden Co., Ltd.) , And the maximum stress exhibited during the passage of the needle through was determined as the film strength (mN). Measurement conditions other than the above were in accordance with JIS Z 1707 (1997).

For the support to be the object, the above measurement was carried out three times to calculate the film strength, and the average value of three times was taken as the film strength of the support.

Production Example 1

(Production of PLA film)

L-lactic acid] / [D-lactic acid] = 50/50 (molar ratio)) was dissolved in ethanol, and the resultant solution was added to a polylactic acid resin (PURASORB (R) PDL20, To prepare a polylactic acid ethanol solution having a resin content (resin content) concentration of 5% by mass.

Then, a polyolefin film (manufactured by Zeon Corporation, product name "Zeonoa", thickness: 50 μm) was prepared as an application sheet, and the above-mentioned polylactic acid ethanol solution was applied on the application sheet so as to have a predetermined thickness after drying And dried at 100 ° C for 2 minutes to prepare a polylactic acid film laminated on the application sheet.

Further, the polylactic acid film was manufactured to have thicknesses of 0.2 탆, 0.5 탆, 0.7 탆, 1.0 탆, and 2.0 탆, respectively.

Details of the support and the pressure-sensitive adhesive used in Examples and Comparative Examples are shown below.

<Support>

ㆍ PLA film (0.2):

A polylactic acid film (film strength = 40 mN) having a thickness of 0.2 占 퐉 produced in Production Example 1.

ㆍ PLA film (0.5):

A polylactic acid film (film strength = 45 mN) having a thickness of 0.5 m prepared in Preparation Example 1 was used.

ㆍ PLA film (0.7):

A polylactic acid film (film strength = 97 mN) having a thickness of 0.7 占 퐉 produced in Production Example 1.

ㆍ PLA film (1.0):

A polylactic acid film (film strength = 230 mN) having a thickness of 1.0 탆 prepared in Preparation Example 1.

ㆍ PLA film (2.0):

A polylactic acid film (film strength = 480 mN) having a thickness of 2.0 占 퐉 produced in Production Example 1.

ㆍ PET film (0.5):

A polyethylene terephthalate (PET) film (film strength = 180 mN) having a thickness of 0.5 탆.

ㆍ PET film (6.0):

A PET film having a thickness of 6.0 탆 (film strength = 2040 mN).

ㆍ Polyurethane film (6.0):

A polyurethane film (film strength = 1540 mN) having a thickness of 6.0 탆 was prepared based on the description of Production Example 4 of paragraph [0073] of Patent Document 2, except that the thickness was changed from 2 탆 to 6.0 탆.

<Adhesive>

ㆍ Adhesive (1):

100 parts by mass of an acrylic copolymer (BA / 2AOE = 90/10 (molar ratio), Mw = 280,000) obtained by polymerizing n-butyl acrylate (BA) and succinic acid mono (2-acryloyloxyethyl) (Solids content part) and 0.45 part (solid content part) of an isocyanate type crosslinking agent (trade name: "Coronate L", product of Tosoh Corporation) were mixed and diluted with ethyl acetate to obtain a solution of acrylic pressure-sensitive adhesive having a solid content concentration of 13% by mass .

ㆍ Adhesive (2):

100 parts by mass (solid part by mass) of an acrylic copolymer (BA / AAc = 96/4 (mole ratio), Mw = 1 million) obtained by polymerizing n-butyl acrylate (BA) and acrylic acid (AAc) (Solids content part)) and 0.1 part by mass (solids content part) of an isocyanate crosslinking agent (product name: &quot; Coronate L &quot;, trade name, manufactured by TOSO CO., LTD.) Were mixed, A solution of an acrylic pressure-sensitive adhesive diluted with ethyl and having a solid content concentration of 13 mass%.

ㆍ Adhesive (3):

acrylic copolymer (BA / 2EHA / AAc / 4HBA) obtained by polymerizing n-butyl acrylate (BA), 2-ethylhexyl acrylate (2EHA), acrylic acid (AAc), and 4-hydroxybutyl acrylate 30 parts by mass (solid content parts by mass), 100 parts by mass (solid part by mass), tackifier (product of Arakawa Chemical Industries, Ltd., product name: &quot; Phencel D125 &quot;), , And 2 parts by mass (solid part by mass) of an isocyanate-based crosslinking agent (product name: "Coronate L", trade name, manufactured by Tosoh Corporation) were mixed and diluted with ethyl acetate at a solid concentration of 13% by mass.

Examples 1 to 6 and Comparative Examples 2 to 5

The pressure-sensitive adhesive of the kind shown in Table 1 was applied onto the release-treated surface of a heavy-duty recoated sheet (manufactured by LINTEC CORPORATION, product name "SP-PET381031", PET film having a thickness of 38 mu m peeled off with a silicone release agent) And dried for a minute to form a first pressure-sensitive adhesive layer having a thickness shown in Table 1.

Then, on the surface of the exposed first pressure-sensitive adhesive layer, a support of the kind shown in Table 1 was bonded to obtain a single-sided pressure-sensitive adhesive sheet.

In the case where various PLA films are used as the support, in order to maintain the handling property, the surface of the PLA film on the side where the application sheet is not laminated and the first pressure sensitive adhesive layer After the application, the application sheet was removed to obtain a single-sided pressure-sensitive adhesive sheet.

In addition, on the exfoliated surface of a light release sheet (manufactured by LINTEC CORPORATION, product name "SP-PET381130", a PET film having a thickness of 38 mu m peeled off with a silicone release agent) prepared in the same manner as described above, A pressure-sensitive adhesive of the kind shown in Table 1 was applied and dried at 100 ° C for 1 minute to form a second pressure-sensitive adhesive layer having a thickness shown in Table 1.

Then, the surface of the above-described single-sided pressure-sensitive adhesive sheet on the support side and the surface of the second pressure-sensitive adhesive layer are respectively laminated, and the intermediate pressure-sensitive adhesive layer, the first pressure-sensitive adhesive layer, the support, the second pressure- Sided pressure-sensitive adhesive sheet (P).

In the same manner as in the production process of the double-sided pressure-sensitive adhesive sheet P, except that the above-mentioned "heavy-weight recycled sheet" was replaced with "light-exfoliation sheet (product name:" SP-PET381130 " Sensitive adhesive sheet (Q) having a structure in which a release sheet, a first pressure-sensitive adhesive layer, a support, a second pressure-sensitive adhesive layer, and a light-releasing sheet were laminated in this order were also produced.

Comparative Example 1

The pressure-sensitive adhesive (1) was coated on the release-treated surface of a heavy-duty recoated sheet (manufactured by LINTEC CORPORATION, product name "SP-PET381031") and dried at 100 ° C for 1 minute to form a pressure-sensitive adhesive layer having a thickness of 2 μm.

Then, a light-exfoliation sheet (product name: "SP-PET381130", manufactured by LINTEC CO., LTD.) Was laminated on the surface of the formed pressure-sensitive adhesive layer thus formed, and a heavy-weighted sheet, an adhesive layer and a light- Sided pressure-sensitive adhesive sheet (P ').

In the same manner as in the production process of the double-faced pressure-sensitive adhesive sheet P 'except that the above-mentioned "heavy-weight recycled sheet" was replaced with "light-exfoliation sheet" (product name: "SP-PET381130" Sensitive adhesive sheet (Q) having a structure in which a release sheet, a first pressure-sensitive adhesive layer, a support, a second pressure-sensitive adhesive layer, and a light-releasing sheet were laminated in this order were also produced.

The following evaluations were carried out using the double-sided pressure-sensitive adhesive sheet (P) or (P ') and the double-sided pressure-sensitive adhesive sheet (Q) prepared in Examples and Comparative Examples. The results are shown in Table 1.

(Evaluation 1) Adhesive strength measurement

Sensitive adhesive sheet (P) or (P ') prepared in Examples and Comparative Examples was peeled off and the polyester film having a thickness of 25 占 퐉 was attached to the surface of the exposed pressure-sensitive adhesive layer , And cut into 25 mm x 300 mm to prepare a test piece.

Next, the heavy-weight recycled sheet of the test piece was peeled off under an environment of 23 ° C and 50% RH (relative humidity), and the surface of the exposed pressure-sensitive adhesive layer was stuck to a stainless steel plate (SUS304 steel plate, polished No. 120) And allowed to stand for 24 hours under the same environment.

The adhesive force after 24 hours from the application under the same environment was measured at a tensile rate of 300 mm / min by a 180 ° peeling method in accordance with JIS Z 0237: 2000.

(Evaluation 2) Adhesive residue test

The double-sided pressure-sensitive adhesive sheet (Q) prepared in Examples and Comparative Examples was subjected to 20 times of checking whether the pressure-sensitive adhesive sheet remained at the interface between the lightly-peeling sheet and the pressure-sensitive adhesive layer when the lightly- And evaluated according to the following criteria.

A: No adhesive residue remained at all 20 times.

B: Residual adhesive occurred once in 20 times, which was confirmed.

C: Residual adhesive remained twice or more out of 20 times.

Table 1 shows that the double-sided pressure-sensitive adhesive sheets produced in Examples 1 to 6 exhibited excellent adhesive force without causing a residual adhesive phenomenon, despite the fact that the pressure-sensitive adhesive layer was thinned.

On the other hand, in the double-sided pressure-sensitive adhesive sheet produced in Comparative Example 1, the frequency of occurrence of the adhesive remnant phenomenon was high. The double-sided pressure-sensitive adhesive sheets produced in Comparative Examples 2 to 5 were able to suppress the occurrence of the residual pressure-sensitive adhesive, but the pressure-sensitive adhesive layer was made thinner, .

Industrial availability

The double-sided pressure-sensitive adhesive sheet of the present invention can exhibit a sufficiently high adhesive force even when it is made thin, so that the effect of suppressing the residual pressure-sensitive adhesive property is excellent.

Therefore, the double-faced pressure-sensitive adhesive sheet of the present invention can be applied to various applications such as bonding of two members at a point where the clearance is narrow or temporary bonding at the time of processing, Suitable.

1, 2: Double-sided adhesive sheet
11: Support
12a: first pressure-sensitive adhesive layer
12b: second pressure-sensitive adhesive layer
13a, 13b: peeling material

Claims (8)

Sensitive adhesive sheet having a first pressure-sensitive adhesive layer and a second pressure-sensitive adhesive layer on both sides of a support,
Wherein the support comprises polylactic acid and the support has a thickness of 1.5 m or less. The method according to claim 1,
Wherein the support has a film strength of 1 to 300 mN. 3. The method according to claim 1 or 2,
Wherein the content of the polylactic acid is 70 to 100% by mass with respect to the total mass of the support. 4. The method according to any one of claims 1 to 3,
Wherein at least one of the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer is a layer formed of an acrylic pressure-sensitive adhesive containing an acrylic resin. 5. The method according to any one of claims 1 to 4,
Wherein the thickness of each of the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer is independently 0.5 to 3.0 占 퐉. 6. The method according to any one of claims 1 to 5,
Wherein the ratio of the thickness of the support to the total thickness of 100 of the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer is 5.0 to 70.0. 7. The method according to any one of claims 1 to 6,
Wherein the total thickness of the double-sided pressure-sensitive adhesive sheet when pasting to two adherends via the double-sided pressure-sensitive adhesive sheet is 6.0 占 퐉 or less. 8. The method according to any one of claims 1 to 7,
The adhesive strength measured in accordance with JIS Z 0237: 2000 after lapse of 24 hours after being attached to a stainless steel plate (SUS 304 steel plate, 120 polish) in an environment of 23 ° C and 50% RH (relative humidity) was 1.5 N / 25 mm Sided adhesive sheet.

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