TWI568828B - Adhesive sheet - Google Patents

Description

Adhesive film

The present invention relates to an adhesive sheet. Specifically, it relates to an adhesive sheet for removing an adhesive layer attached to glass or the like.

In recent years, electronic devices such as mobile phones, portable game machines, and digital cameras have rapidly spread. The fixing of the parts constituting the electronic machine or the various devices generally uses an adhesive sheet. As the adhesive sheet used for fixing the part, an adhesive sheet in which an adhesive layer is provided on one surface or both surfaces of the substrate is used (Patent Document 1).

Further, a flat panel display (FPD) such as a liquid crystal display (LCD) is widely used as a display device. In such a display device, various optical members such as an antireflection film for preventing reflection from an external light source or a protective film for preventing damage of the surface of the display device are generally used depending on the application. An adhesive sheet is also used for bonding the optical members of the display devices (Patent Document 2).

In the adhesive layer of the adhesive sheet disclosed in Patent Documents 1 and 2, an acrylic polymer is often used, and the adhesive layer is provided on one side or both sides of the support (substrate).

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2012-140605

[Patent Document 2] Japanese Patent Laid-Open Publication No. 2003-238915

In the adhesive sheet used for the above-mentioned application, when the members are bonded to each other and the adhesiveness is excellent, and the re-attachment is required, the demand for rework (re-peeling) is increased. In particular, when the liquid crystal display device is bonded to other members (for example, a touch panel module), or when the cover glass and the anti-scattering film are bonded together, such as dirt biting, the price is relatively high for reuse. There is a high demand for high liquid crystal display devices or cover glass for rework. However, in the adhesive sheets described in Patent Documents 1 and 2, there is a problem that the reworkability is insufficient and the adhesive remains in the adherend during the return to work. The adhesive remaining on the adherend needs to be wiped with a solvent or washed with a solvent, and there is a problem that labor and time are required to return to the work.

Therefore, the inventors of the present invention have provided an adhesive sheet which can easily remove an adhesive adhering to an adherend by attaching to an adhesive surface to be removed and peeling off in order to solve the problems of the prior art. Conduct research for the purpose. Further, the inventors of the present invention have conducted research for the purpose of providing an adhesive sheet having sufficient adhesion and exhibiting excellent reworkability.

In order to solve the above problems, the inventors of the present invention have found that by setting the elongation at break of the adhesive sheet, the stress at the breaking point, and the adhesion to the acrylic adhesive surface to a certain value or more, it is obtained. Adhesive sheet with excellent adhesive removal performance. Further, the inventors of the present invention have found that such an adhesive sheet has sufficient adhesion to an adherend and can exhibit excellent reworkability, thereby completing the present invention. Specifically, the present invention has the following constitution.

[1] An adhesive sheet characterized by having an elongation at break of 500% or more, a stress at a breaking point of 1.0 N/mm ² or more, and an adhesive force to an acrylic adhesive surface of 15 N/25 mm or more.

[2] The adhesive sheet according to [1], which comprises a rubber-based resin as a main component.

[3] The adhesive sheet of [2], wherein the rubber-based resin is a styrene-based copolymer.

[4] The adhesive sheet of [2] or [3] wherein the rubber-based resin is a styrene-based block copolymer, and the styrene-based block copolymer contains a block which polymerizes styrene, and is selected from the group consisting of At least one polymerized block of ethylene, propylene and butene.

[5] The adhesive sheet according to [4], wherein the content of the block in which styrene is polymerized is from 10 to 50% by mass based on the styrene block copolymer.

[6] The adhesive sheet according to any one of [2] to [5] wherein the rubber-based resin is an ABA-type triblock copolymer, A is a block which polymerizes styrene, and B is selected from ethylene. At least one polymerized block of propylene and butene.

[7] The adhesive sheet according to any one of [1] to [6] wherein the adhesive sheet contains a rubber-based resin, an adhesive-imparting agent, and a plasticizer, and the content of the adhesive-imparting agent is 100 parts by mass relative to the rubber-based resin. 10 to 90 parts by mass, the content of the plasticizer is 10 to 80 parts by mass based on 100 parts by mass of the rubber-based resin.

[8] The adhesive sheet according to any one of [1] to [7] wherein the adhesive sheet is a double-sided adhesive sheet.

[9] The adhesive sheet according to any one of [1] to [8], which has a thickness of 80 μm or more.

[10] The adhesive sheet according to any one of [1] to [9] which is used for bonding to an optical member.

[11] The adhesive sheet of [10], wherein the optical member is a liquid crystal cell or a touch panel.

[12] The adhesive sheet according to any one of [1] to [11] which is a single layer without a support.

[13] An adhesive sheet with a release sheet, which is a release sheet of at least one area of the adhesive sheet according to any one of [1] to [12].

[14] An adhesive sheet with a release sheet, which is a double-layered release sheet of the adhesive sheet according to any one of [1] to [12].

According to the present invention, an adhesive sheet having excellent adhesive removal performance can be obtained. Further, the adhesive sheet of the present invention has sufficient adhesion to the adherend and exhibits excellent reworkability.

10‧‧‧Adhesive tablets

20‧‧‧1st peeling piece

30‧‧‧2nd peeling piece

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a cross-sectional view showing an adhesive sheet of the present invention.

Fig. 2 is a cross-sectional view showing an adhesive sheet with a release sheet of the present invention.

Hereinafter, the present invention will be described in detail. The description of the constituent elements described below is based on a representative embodiment or a specific example, but the present invention is not limited to such an embodiment. In the present specification, the numerical range expressed by "~" means a range including the numerical values described before and after "~" as the lower limit value and the upper limit value.

(adhesive film)

The present invention relates to an adhesive sheet having an elongation at break of 500% or more, a stress at a breaking point of 1.0 N/mm ² or more, and an adhesion to an acrylic adhesive surface of 15 N/25 mm or more. The adhesive sheet of the present invention is characterized in that the elongation at break and the stress at the breaking point are set to be equal to or higher than the above values, and the peeling force corresponding to the application to the adhesive sheet is easily elongated during the returning work, and the adhesive sheet is hard to be broken. In addition, the adhesive sheet of the present invention has an adhesive strength to the acrylic adhesive surface of at least the above value, and exhibits excellent adhesion to the adhesive remaining on the adherend. Therefore, the adhesive remaining on the adherend can be easily removed by attaching the adhesive sheet of the present invention to the adherend which remains with the adhesive to be removed and peeling off. That is, the adhesive sheet of the present invention exerts excellent adhesion to the adherend and the residual adhesive, and exhibits excellent adhesive removal performance.

Furthermore, since the adhesive sheet of the present invention has sufficient adhesion to the adherend, it can also be used for the bonding of various members. In this case, the adhesive sheet of the present invention can exhibit excellent reworkability. Here, the rework performance refers to a property in which one part of the adhesive of the adhesive sheet does not remain in the adherend during peeling after the attachment, and the adhesive sheet does not break in the returning work.

The elongation at break and the stress at the fracture point were measured in accordance with JIS K 6251 using a tensile tester. The measurement can be carried out by stretching the sample (adhesive sheet) into a rod having a diameter of 5 mm and a length of 70 mm by the initial distance between the chucks: 50 mm and the stretching speed: 1000 mm/min. Further, the above tensile test was carried out in an environment of 23 ° C and a relative humidity of 50%. The elongation at break point indicates the elongation between the punctuation points of the test piece (adhesive sheet) in the tensile test immediately before the break. Further, the breaking point stress is a value obtained by dividing the tensile force at the breaking point at the time of breaking in the tensile test by the initial sectional area of the test piece. Further, in the above tensile test, the elongation at break and the stress at the fracture point in the longitudinal direction of the adhesive sheet were measured.

The elongation at break of the adhesive sheet may be 500% or more, preferably 600% or more, more preferably 800% or more, still more preferably 1,000% or more. The breaking point stress of the adhesive sheet may be 1.0 N/mm ² or more, preferably 1.5 N/mm ² or more, more preferably 2.0 N/mm ² or more, still more preferably 3.0 N/mm ² or more.

The adhesive force of the adhesive sheet to the acrylic adhesive surface may be 15 N/25 mm or more, preferably 20 N/25 mm or more, and more preferably 25 N/25 mm or more. When the adhesion to the acrylic adhesive surface is measured, the adhesive for measuring the adhesive force of the adhesive sheet of the present invention is an acrylic adhesive sheet (manufactured by NEW TAC KASEI Co., Ltd., CPETT75HNA/DP). /T7) The release film is peeled off as an adherend. The measurement of the adhesion can be carried out in accordance with JIS Z 0237.

When the elongation at break of the adhesive sheet is A and the stress at the breaking point is B, it is preferably 100 < A / B < 1000, more preferably 200 < A / B < 800. By setting the relationship between the elongation at break point and the stress at the breaking point within the above range, the peeling force corresponding to the application to the adhesive sheet can be easily elongated, and the breakage of the adhesive sheet can be suppressed.

The adhesive sheet of the present invention preferably has a rubber-based resin as a main component. Examples of the rubber-based resin include a natural rubber-based resin or a synthetic rubber-based resin. Here, the rubber-based resin as a main component means that the rubber-based resin is contained in an amount of 30% by mass or more based on the total mass of the pressure-sensitive adhesive sheet, and preferably contains 35% by mass or more, more preferably 45% by mass. the above.

The rubber-based resin is preferably a synthetic rubber-based resin, and examples of the synthetic rubber-based resin include styrene-isoprene-styrene block copolymer (SIS) and styrene-butadiene-styrene block copolymerization. Synthetic (SBS), hydride of styrenic block copolymer, styrene-butadiene rubber (SBR), polyisoprene rubber (IR), polyisobutylene (PIB), butyl rubber (IIR), etc. . These synthetic rubbers may be used singly or in combination of two or more.

Among them, the rubber-based resin is preferably a styrene-based copolymer, and more preferably a styrene-based block copolymer. The styrene block copolymer preferably contains a block which polymerizes styrene, and at least one selected from the group consisting of ethylene, propylene and butene. Block. The at least one polymerized block selected from the group consisting of ethylene, propylene, and butene may also be a block that polymerizes the hydrides. Further, the block in which styrene is polymerized may be a block having styrene as a main constituent component, and may contain other components such as ethylene. The block in which styrene is polymerized preferably contains 90% by mass or more of a component derived from styrene, more preferably 95% by mass or more. Further, a block obtained by polymerizing at least one selected from the group consisting of ethylene, propylene and butene may also contain other constituent components in the same manner.

It is preferred that at least one polymerized block selected from the group consisting of ethylene, propylene and butene is a block containing a polymer comprising ethylene and butene. Such a block may be a block copolymer comprising a block of ethylene and a block of butene, or a random copolymer of ethylene and butene.

The content of the block which polymerizes styrene contained in the styrene block copolymer is preferably 10 to 50% by mass, more preferably 10 to 40% by mass based on the styrene block copolymer. Further, it is preferably 10 to 35 mass%. Further, the content ratio of the block in which styrene is polymerized is the content ratio of the block in which the styrene is polymerized in the styrene block copolymer, and the content of styrene contained in the entire adhesive sheet. different. In the present invention, by setting the content of the block which polymerizes styrene contained in the styrene block copolymer to the above range, the adhesion to the acrylic adhesive surface can be made necessary. Within the range, it is preferable to use an adhesive sheet for acrylic adhesive removal. In addition, by setting the content of the block in which styrene is polymerized within the above range, the viscosity (immediate adhesion) of the adhesive sheet to the acrylic adhesive surface can be suppressed, so that it can be improved as an acrylic adhesive. Remove the rationality of using adhesive sheets.

Further, the rubber-based resin is preferably an A-B-A type triblock copolymer. Here, A of the A-B-A type triblock copolymer is a block in which styrene is polymerized, and B is At least one polymerized block selected from the group consisting of ethylene, propylene, and butene is used. Further, B may be a block of two or more random copolymers selected from the group consisting of ethylene, propylene, and butene. Even when B is a random copolymer, the copolymer is classified into an ABA type three-embedded. Segmental copolymer. Further, B may be a block copolymer of two or more selected from the group consisting of ethylene, propylene, and butene. Even when two types of blocks are included, the copolymer is classified into an ABA type triblock copolymer. .

Examples of the ABA type triblock copolymer include a styrene block copolymer (styrene-hydrogenated isoprene-styrene triblock copolymer) of the following formula (1), and the following formula ( 2) a styrene block copolymer (styrene-(ethylene/butylene)-styrene triblock copolymer), a styrenic block copolymer of the following formula (3) (styrene-( A hydrogenated ethylene/isoprene)-triblock copolymer of styrene or the like.

In the formula (1), m represents a degree of polymerization, and PS represents a block in which styrene is polymerized. m can be calculated from the molecular weight of the styrene block copolymer.

In the formula (2), m and n respectively represent the degree of polymerization, and PS represents styrene. Polymerized block. m and n can be calculated from the molecular weight of the styrene block copolymer.

In the formula (3), m represents a degree of polymerization, and PS represents a block which polymerizes styrene. m can be calculated from the molecular weight of the styrene block copolymer.

Preferably, in the A-B-A type triblock copolymer, A is a block which polymerizes styrene, and B is a block which polymerizes hydrogenated isoprene.

The weight average molecular weight (Mw) of the rubber-based resin is preferably from 10,000 to 1,000,000, more preferably from 50,000 to 800,000, still more preferably from 80,000 to 500,000. Further, the weight average molecular weight (Mw) was measured by gel permeation chromatography (GPC) and calculated based on a calibration curve prepared using a polystyrene standard material.

(additive)

The adhesive sheet of the present invention contains a rubber-based resin as a main component. Further, the adhesive sheet of the present invention preferably contains an adhesion-imparting agent and a plasticizer. Examples of the adhesion-imparting agent include petroleum-based resins such as a styrene resin, a terpene resin, a rosin resin, a C5 resin, a C9 resin, and a C5/C9 resin. Among them, a styrene resin (styrene-based adhesion-imparting agent) can be preferably used.

The content of the adhesion-imparting agent is preferably 10 to 90 parts by mass, more preferably 10 to 80 parts by mass, even more preferably 20 to 80 parts by mass, per 100 parts by mass of the rubber-based resin. Effectively remove the residue by setting the content of the adhesion-imparting agent within the above range Adhesive to the adhesive. Further, by setting the content of the adhesion-imparting agent within the above range, an adhesive sheet which improves the adhesion of the pressure-sensitive adhesive sheet and exhibits excellent reworkability can be obtained.

As the adhesion-imparting agent, in order to exhibit the adhesive force at a low temperature and the cohesive force at a high temperature, an adhesion-imparting agent having a softening point of 100 ° C or less and an adhesion-imparting agent of 120 ° C or more may be used in combination. The adhesive sheet containing such an adhesion-imparting agent can be suitably used in a wide range of temperature environments.

As the plasticizer, an oil component or a phthalate ester or the like can be used, and it is particularly preferably an oil component in terms of environmental or safety. The oil component acts to control the elongation at break of the adhesive sheet and the stress at the break point. As the oil component, a paraffin-based or naphthenic system oil is preferable, and it is more difficult to cause deterioration of the rubber, and the paraffin-based system oil can be more preferably used. The content of the plasticizer varies depending on the molecular weight of the rubber-based resin to be used, etc., and is preferably 10 to 90 parts by mass, more preferably 10 to 80 parts by mass, even more preferably 10 parts by mass based on 100 parts by mass of the rubber-based resin. ~70 parts by mass, particularly preferably 20 to 70 parts by mass.

Further, additives such as a softener, a crosslinking agent, and a pigment may be blended in the adhesive sheet as needed.

Further, in order to prevent deterioration of the adhesive sheet over time, it is preferred to add an anti-aging agent. By adding an anti-aging agent, the adhesion caused by the deterioration of the adhesive sheet can be prevented from being lowered. Examples of the anti-aging agent include a general phenolic antioxidant, a phosphorus-based antioxidant, an ultraviolet-ray inhibitor, and a hindered amine light stabilizer (HALS). The amount of the anti-aging agent to be added is preferably 0.05 to 5 parts by mass, more preferably 0.1 to 3 parts by mass, per 100 parts by mass of the rubber-based resin.

(Composition of adhesive sheets)

The adhesive sheet of the present invention may be a laminated adhesive sheet having an adhesive sheet on at least one area of the support (substrate), preferably a single-layer double-sided adhesive sheet 10 as shown in FIG. That is, the adhesive sheet of the present invention preferably has a support (substrate) and is a single layer. The adhesive sheet of the present invention has less stickiness (immediate adhesion) than the acrylic adhesive surface, and thus has less stickiness. Therefore, the adhesive sheet of the present invention is excellent in workability even if it does not have a support (substrate). Here, the adhesive sheet is a single layer, and means a double-sided adhesive sheet which does not have a support (substrate), and means that in the entire thickness region, the elongation at break point is only 500% or more, and the fracture point stress is 1.0. An adhesive sheet having an N/mm ² or more adhesive force to an acrylic adhesive surface of 15 N/25 mm or more constitutes an adhesive sheet.

In the case where the adhesive sheet has a support (substrate), it is preferred that the elongation at break of the support (substrate) is also 500% or more. That is, it is preferred that the support (substrate) also has the same elongation as the adhesive layer constituting the adhesive sheet. Further, when the elongation at break of the adhesive sheet is P and the elongation at break of the support (base material) is Q, the P/Q is preferably 0.3 to 3.0.

Specifically, as the support (base material), it is preferred to use a substrate having good adhesion to a rubber-based adhesive and having a large elongation at break. Specifically, a urethane sheet and a soft polyvinyl chloride sheet are mentioned.

The thickness of the adhesive sheet is preferably 80 μm or more, more preferably 100 μm or more. The adhesive sheet of the present invention can easily remove the adhesive remaining on the adherend by having a certain thickness or more. Further, the reworkability of the adhesive sheet can be further improved.

(Adhesive sheet with peeling sheet)

Preferably, the sheet is peeled off at least one area of the adhesive sheet, and the adhesive sheet of the present invention is preferably an adhesive sheet with a release sheet. The release sheet is preferably laminated on at least one side of the adhesive sheet, more preferably laminated on both sides as shown in FIG. The release sheet can be used for a polymer film provided with a release agent layer. As shown in FIG. 2, in the case of the double-layer peeling sheet of the adhesive sheet 10, it is preferable that two peeling sheets (the first peeling sheet 20 and the second peeling sheet 30) have different peeling forces, specifically, It is preferred to use different strippers. By peeling off the release sheets having different peeling forces as described above, it is possible to suppress the adhesion separation phenomenon in which the release sheets on the self-weight peeling force side of the adhesive sheet are lifted when the release sheet on the light release force side is peeled off. The peeling force of the peeling sheet on the heavy peeling force side is preferably 0.08 to 0.80 N/50 mm, and the peeling force of the peeling sheet on the light peeling force side is preferably 0.01 to 0.20 N/50 mm. Further, the ratio (R _H /R _L ) of the peeling force R _H on the heavy peeling force side to the peeling force R _L of the sheet on the light peeling force side is preferably 1.5 or more.

Further, in the case of the double-layer peeling sheet of the adhesive sheet, when the peeling force difference between the two peeling sheets can be maintained, the adhesive coating liquid may be applied before the second peeling sheet. The first release sheet is crimped and bonded. The shape of the adhesive sheet may be a sheet shape or may be rolled into a roll shape.

The adhesive sheet of the present invention is also characterized in that it has excellent shape retention. In general, a single-layer double-sided adhesive sheet is difficult to maintain its shape in a state where the release sheet is peeled off. For example, it is present in the adhesive sheet, a part is followed by another part, or wrinkled. In this case, the projected area of the adhesive sheet after peeling of the double-sided peeling sheet is smaller than that of the adhesive sheet before peeling off, and the adhesive surface is reduced, so that the adhesive removal area is reduced, or operation is performed. Sexual deterioration. However, since the adhesive sheet of the present invention is excellent in shape retention, it is suitable as an adhesive sheet for adhesive removal even if it is a single layer, and it is excellent in handleability. Specifically, in the adhesive sheet of the present invention, the area (cm ² ) of the adhesive sheet before peeling off the release sheet is S, and the projected area (cm ² ) of the adhesive sheet after peeling off the double-sided release sheet is set. When it is set to T, it is preferable that T/S>0.9, and it is more preferable that it is T/S>0.95. Further, the projected area (cm ² ) T of the adhesive sheet after peeling of the double-sided release sheet has only the projected area of the adhesive surface of the single-layer adhesive sheet from which one corner of the adhesive sheet is peeled off from the release sheet.

(Method of manufacturing adhesive sheet)

The adhesive sheet of the present invention is formed by coating an adhesive sheet with an adhesive. The adhesive for an adhesive sheet is preferably obtained by uniformly mixing a rubber-based resin, an adhesion-imparting agent, and an oil component. The method for producing the adhesive for an adhesive sheet is a method in which a commercially available granular rubber-based resin is dissolved in a solvent such as toluene, and a pressure-imparting agent or an oil component is mixed; or The rubber of the shape is heated and softened, and a method of kneading the adhesion imparting agent or the oil component by a kneader is used. The sheet can be formed by coating the thus-prepared adhesive sheet with an adhesive by a conventional method. In the case of using an adhesive prepared by dissolving in a solvent, after coating with a knife coater or the like, the solvent can be dried by a drying oven to form a sheet. On the other hand, in the case of using an adhesive produced by a kneading method by heating, a hot melt coater which can soften the adhesive by heating in advance can be used, whereby sheeting can be achieved.

Preferably, the adhesive sheet is formed on the first release sheet, and it is preferable to form the second release sheet after forming the adhesive sheet on the first release sheet by the above method. Thus, it is possible to manufacture an adhesive sheet with a release sheet attached to the double-layered layer of the adhesive sheet.

(Adhesive removal adhesive sheet)

The adhesive sheet of the present invention can be used as an adhesive sheet for adhesive removal. Specifically, the adhesive sheet of the present invention is attached to the adhesive surface remaining on the adherend, and the adhesive sheet is peeled off to remove the residual adhesive adhering to the adherend. As attached to the adherend Examples of the residual adhesive include an acrylic adhesive, a polyoxygen adhesive, and a rubber adhesive. The adhesive sheet of the present invention can exhibit excellent adhesive removal performance especially for a residual acrylic adhesive. It is used as an adhesive for removing acrylic adhesives.

(adhesive sheet for optical members)

The adhesive sheet of the present invention can be preferably used for the bonding of various members. The use of the bonding is not limited, and is preferably used for bonding to an optical member. Examples of the optical member include a liquid crystal cell or a touch panel.

(image display device)

The present invention may also be directed to an image display device including an adhesive sheet for an optical member. The image display device can be produced by laminating the adhesive sheet of the present invention to an optical member and incorporating the optical member with the adhesive sheet into the image display device.

[Examples]

The features of the present invention will be further specifically described below by way of examples and comparative examples. The materials, the amounts, the ratios, the processing contents, the processing procedures, and the like shown in the following examples can be appropriately changed without departing from the gist of the present invention. Therefore, the scope of the invention should not be construed as limited to the specific examples shown below.

(Example 1) [Manufacture of adhesive for adhesive sheets]

Styrene block copolymer (styrene-hydrogenated isoprene-styrene triblock copolymer) (manufactured by Kuraray Co., Ltd., Septon 2063) 100 parts by mass, styrene 70 parts by mass of an adhesion-imparting agent (manufactured by Mitsui Chemicals, Inc., FTR8100), 50 parts by mass of paraffin-based oil (manufactured by Idemitsu Co., Ltd., Diana Process Oil PW-90), dissolved in toluene, and stirred until uniform to obtain a solid concentration of 45 mass. % toluene solution of the adhesive. The weight average molecular weight (Mw) of the styrene block copolymer was converted by a gel permeation chromatography (GPC) using a polystyrene standard material, and it was 120,000. In addition, the solid content means a rubber component, an adhesion-imparting agent, and an oil component.

[Production of adhesive sheets]

The adhesive sheet prepared in the above-mentioned adhesive sheet was applied to the peeling sheet on the heavy peeling force side by drying to a thickness of 100 μm by a doctor blade (manufactured by Prince F-Tex, RL-07 (2) After that, it was dried at 100 ° C for 3 minutes, and the toluene solvent was dried to obtain a double-sided adhesive sheet. On the obtained adhesive sheet, a release sheet (manufactured by Prince F-Tex Co., Ltd., RL-07 (L)) on the light release force side was laminated, whereby an adhesive sheet with a release sheet was obtained.

(Example 2)

In the manufacturing step of the adhesive for an adhesive sheet, the addition amount of the styrene-based adhesion-imparting agent was changed to 30 parts by mass, and the amount of the paraffin-based oil produced by the company was changed to 25 parts by mass. 1 Adhesive sheet with a release sheet was obtained in the same manner.

(Example 3)

A peeling was obtained in the same manner as in Example 1 except that a triblock copolymer of styrene-(ethylene/butylene)-styrene (Septon 8007L, manufactured by Kuraray Co., Ltd.) was used as the styrene block copolymer. Adhesive piece of film. Gel permeation chromatography (GPC) measurement, the weight average molecular weight (Mw) of the styrene block copolymer was converted using a polystyrene standard material, and it was 100,000.

(Example 4)

A method similar to that of Example 1 was carried out except that a triblock copolymer of styrene-(hydrogenated ethylene/isoprene)-styrene (manufactured by Kuraray Co., Ltd., HYBRAR 7311) was used as the styrene block copolymer. An adhesive sheet with a release sheet was obtained. The weight average molecular weight (Mw) of the styrene block copolymer was converted by a gel permeation chromatography (GPC) using a polystyrene standard material, and it was found to be 160,000.

(Comparative Example 1)

An adhesive sheet with a release sheet was obtained in the same manner as in Example 1 except that NA084 (manufactured by Suntec Chemical Co., Ltd., OCA/acrylic) was used as the double-sided adhesive sheet.

(Comparative Example 2)

An adhesive sheet with a release sheet was obtained in the same manner as in Example 1 except that SA114 (manufactured by Suntec Chemical Co., Ltd., OCA/acrylic) was used as the double-sided adhesive sheet.

(Comparative Example 3)

In the same manner as in the first embodiment, the amount of the styrene-based adhesion-imparting agent is changed to 100 parts by mass, and the amount of the paraffin-based oil to be added is changed to 100 parts by mass. An adhesive sheet with a release sheet was obtained.

(Evaluation) (Method for measuring elongation at break point and stress at break point)

A stick-shaped adhesive sheet having a diameter of 5 mm and a length of 70 mm was attached to a tensile tester, and stretched at a tensile speed of 1000 mm/min at a distance of 50 mm between the chucks, thereby breaking elongation at break point and stress at break point. The measurement was carried out.

(adhesion to acrylic adhesive surface)

The release sheet on the light release force side of the double-sided adhesive sheet of the example or the comparative example was peeled off and bonded to a 100 μm polyethylene terephthalate film (COSMOSHINE A4300, manufactured by Toyobo Co., Ltd.). After the film sheet was adhered, the peeling sheet on the side of the residual heavy peeling force was peeled off, and the adhesive force of the adhesive film sheet was measured. In this case, as the adherend for the measurement of the adhesion, the release surface of the release film of CPETT75HNA/DP/T7 (manufactured by Suntec Chemical Co., Ltd.) was used as the adherend, and the measurement was carried out in accordance with JIS Z 0237. Adhesion.

(Evaluation of adhesive removal performance)

The release film on the light release force side of the non-substrate double-sided tape (hereinafter referred to as OCA/Soda Chemical Co., Ltd.) was peeled off and attached to the glass, and autoclave treatment was carried out (0.5 MPa, 40 ° C, 30). minute). The release film on the heavy peeling force side was peeled off, and the double-sided adhesive sheets of the examples and the comparative examples were attached to the exposed adhesive faces. Thereafter, the laminated body of the double-sided tape and the double-sided adhesive sheet is peeled off from the glass.

○: The laminate was easily and thoroughly peeled off from the glass, and the adhesive from the double-sided tape (OCA) or the adhesive sheet was not left at all in the glass.

△: Although the laminated body was peeled off from the glass, the adhesive sheet was broken in the middle and it was difficult to peel off.

×: Double-sided adhesive sheet is immediately disconnected, or double-sided adhesive sheet and double-sided tape (OCA) The interface is peeled off, and the laminated body or double-sided tape (OCA) is not peeled off from the glass.

(evaluation of rework)

The double-sided adhesive sheets of the examples and the comparative examples were cut out so as to have a size of 5 cm × 5 cm, and the release film on the light release force side was peeled off and bonded to the soda glass. Thereafter, the film was treated under an autoclave at 0.5 MPa and 40 ° C for 30 minutes to remove the release film on the side of the heavy peeling force. Then, the double-sided adhesive sheet is reworked (from the glass peeling) by manual peeling. The reworkability of the double-sided adhesive sheet at this time was evaluated according to the following criteria.

○: The double-sided adhesive sheet was easily and completely peeled off from the glass, and no adhesive remained at all.

△: Although the double-sided adhesive sheet was peeled off from the glass, the adhesive sheet was broken in the middle and it was difficult to peel off.

×: The double-sided adhesive sheet was immediately broken, and the double-sided adhesive sheet was not peeled off from the glass.

In the first embodiment, the adhesion to the acrylic adhesive surface was higher than that of the comparative example, and it was found that the adhesive removal performance was excellent. Moreover, the reworkability of the adhesive sheet of the Example was also excellent.

Claims (12)

An adhesive sheet comprising a rubber-based resin, an adhesion-imparting agent, and a plasticizer, wherein the content of the adhesion-imparting agent is 10 to 90 parts by mass based on 100 parts by mass of the rubber-based resin, and the content of the plasticizer is relative to 100 parts by mass of the rubber-based resin is 10 to 80 parts by mass; the elongation at break is 500% or more, the stress at the breaking point is 1.0 N/mm ² or more, and the adhesion to the acrylic adhesive surface is 15 N/25 mm or more. The adhesive sheet of claim 1, wherein the rubber-based resin is a styrene-based copolymer. The adhesive sheet according to claim 1 or 2, wherein the rubber-based resin is a styrene-based block copolymer, and the styrene-based block copolymer contains a block which polymerizes styrene, and is selected from ethylene and propylene. And at least one polymerized block of butene. The adhesive sheet according to claim 3, wherein the content of the block in which the styrene is polymerized is 10 to 50% by mass based on the styrene block copolymer. The adhesive sheet according to claim 1 or 2, wherein the rubber-based resin is an ABA-type triblock copolymer, and A is a block which polymerizes styrene, and B is at least selected from the group consisting of ethylene, propylene and butene. A polymerized block. The adhesive sheet of claim 1 or 2, wherein the adhesive sheet is a double-sided adhesive sheet. The adhesive sheet of claim 1 or 2 has a thickness of 80 μm or more. An adhesive sheet according to claim 1 or 2, which is for bonding to an optical member. The adhesive sheet of claim 8, wherein the optical member is a liquid crystal cell or a touch panel. The adhesive sheet of claim 1 or 2, which has no support and is a single layer. An adhesive sheet with a release sheet, which is a release sheet of at least one area of the adhesive sheet of any one of claims 1 to 10. An adhesive sheet with a release sheet attached to the double-layered layer of the adhesive sheet of any one of claims 1 to 10 with a release sheet.