KR20240043699A - Release liner-attached pressure-sensitive adhesive sheet and method for producing release liner-attached pressure-sensitive adhesive sheet - Google Patents

Abstract

Provided is an adhesive sheet with a release liner suitable for peeling a light release liner while suppressing peeling of a heavy release liner, and a method of manufacturing the adhesive sheet with a release liner.
The adhesive sheet with release liner (S) includes an adhesive sheet (10) and release liners (20, 30). The release liner 20 is a heavy release liner in contact with the first surface 11 of the adhesive sheet 10. The release liner 30 is a light release liner that comes into contact with the second surface 12 of the adhesive sheet 10. The maximum stress (X) of the release liner 20 against the adhesive sheet 10 in a predetermined shear tensile test is 24 N or more. In the production method of the present invention, the composition layer is irradiated with ultraviolet rays from the side of the release liner 20 to the laminated film (release liner 20/layer of photopolymerizable adhesive composition containing ultraviolet ray absorber/release liner 30). The adhesive sheet 10 is formed by photocuring. The release liner 20 has a vinyl group on the surface on the composition layer side.

Description

An adhesive sheet with a release liner and a method of manufacturing an adhesive sheet with a release liner

The present invention relates to a pressure-sensitive adhesive sheet with a release liner and a method for producing the pressure-sensitive adhesive sheet with a release liner.

The display panel has a laminated structure including elements such as, for example, a pixel panel, a polarizing film, a touch panel, and a cover film. In the manufacturing process of such a display panel, for example, an optically transparent adhesive sheet is used to bond elements included in the laminated structure.

The pressure-sensitive adhesive sheet is manufactured, for example, in the form of a pressure-sensitive adhesive sheet with a release liner in which both sides of the sheet are covered with a release liner. In the adhesive sheet with a release liner, one side of the adhesive sheet is covered with a light release liner, and the other side of the adhesive sheet is covered with a heavy release liner. A light release liner requires less force to peel from the adhesive sheet than a medium release liner. When using the adhesive sheet, the light release liner is peeled from the adhesive sheet before the heavy release liner.

Meanwhile, the development of display panels that can be folded repeatedly (foldable) is in progress, for example, for smartphones and tablet terminals. The foldable display panel can be repeatedly deformed, specifically, between a curved shape and a flat, non-curved shape. In such a foldable display panel, each element in the laminated structure is manufactured so that it can be folded repeatedly. For bonding between such elements, thin adhesive sheets are used. An adhesive sheet for flexible devices such as a foldable display panel is described, for example, in Patent Document 1 below.

Japanese Patent Publication No. 2018-111754

The adhesive sheet for flexible devices is required to be highly soft so as to have sufficient followability to the adherend when the device is deformed and excellent stress relaxation properties. However, in the adhesive sheet with a release liner, the more flexible the adhesive sheet is, the more likely it is that unintended peeling of the heavy release liner will occur when peeling the light release liner from the adhesive sheet.

Meanwhile, the present inventor has obtained the following knowledge regarding the adhesive sheet with a release liner. The pressure-sensitive adhesive sheet with a release liner absorbs moisture and expands slightly in the plane direction after production, for example, during a storage period. The release liner (medium release liner, light release liner) expands more than the adhesive sheet. The adhesive sheet and the heavy release liner have different amounts of dimensional change (differences in the amount of dimensional change). Therefore, a plurality of minute voids (micro voids) are generated between the adhesive sheet and the heavy release liner due to the expansion. That is, the effective contact area between the adhesive sheet and the heavy release liner decreases. As a result, the effective adhesive force of the heavy release liner to the adhesive sheet decreases. Therefore, when peeling the light release liner from the adhesive sheet, unintentional peeling of the heavy release liner becomes more likely to occur.

The present invention provides an adhesive sheet with a release liner that is suitable for peeling a light release liner while suppressing peeling of a heavy release liner, and a method for manufacturing the adhesive sheet with a release liner.

The present invention [1] is an adhesive sheet having a first side and a second side opposite to the first side, a heavy release liner in peelable contact with the first side, and a peelable liner on the second side. A release liner comprising a light release liner that is in close contact with the adhesive sheet, and having a maximum stress ( Includes provided adhesive sheet.

The present invention [2] is the peeling described in [1] above, wherein the average rate of change (Y) (N/mm) from the stress 5N to the stress 10N in the shear tensile test satisfies Y≥-1.43X+70. Includes an adhesive sheet with liner.

The present invention [3] includes the adhesive sheet with a release liner according to [1] or [2] above, wherein the maximum length of the heavy release liner is 20 mm or more.

The present invention [4] is a difference (F1-F2) between the peeling force (F1) for peeling the heavy release liner from the adhesive sheet and the peeling force (F2) for peeling the light release liner from the adhesive sheet. ) includes the pressure-sensitive adhesive sheet with a release liner according to any one of [1] to [3] above, wherein the weight is 10 gf/25 mm or more.

The present invention [5] is a difference (F1-F2) between the peeling force (F1) for peeling the heavy release liner from the adhesive sheet and the peeling force (F2) for peeling the light release liner from the adhesive sheet. ) is 500 gf/25 mm or less, including the adhesive sheet with a release liner described in [1] to [4] above.

The present invention [6] includes the adhesive sheet with a release liner according to the above [1] to [5], wherein the adhesive sheet is a base-less adhesive sheet.

The present invention [7] includes the adhesive sheet with a release liner according to any one of [1] to [6] above, wherein the adhesive sheet is a photocured product of a photopolymerizable adhesive composition containing an ultraviolet absorber.

The present invention [8] is a laminated film comprising a heavy release liner, a composition layer of a photopolymerizable adhesive composition containing an ultraviolet absorber, and a light release liner in this order in the thickness direction, wherein the heavy release liner is the composition layer A preparatory step of preparing a laminated film having a vinyl group on the surface of the side, and an adhesive sheet forming step of photocuring the composition layer to form an adhesive sheet by irradiating ultraviolet rays to the laminated film from the heavy release liner side. It includes a method for producing an adhesive sheet with a release liner, including a method.

In the adhesive sheet with a release liner of the present invention, as described above, the maximum stress ( . Such a pressure-sensitive adhesive sheet with a release liner is suitable for peeling a light release liner while suppressing peeling of a medium release liner.

In the preparation step of the manufacturing method of the present invention, a laminated film is prepared including a heavy release liner, a composition layer, and a light release liner in this order in the thickness direction as described above. In the laminated film, the composition layer is a layer of a photopolymerizable adhesive composition containing an ultraviolet absorber, and the heavy release liner has a vinyl group on the surface on the composition layer side. In the adhesive sheet forming process, ultraviolet rays are irradiated from the heavy release liner side to the laminated film to photocure the composition layer. Since the photopolymerizable adhesive composition forming the composition layer contains an ultraviolet absorber, the ultraviolet rays incident on the composition layer from the heavy release liner side are attenuated due to absorption by the ultraviolet absorber in the composition layer, while being absorbed by the light release liner side. It reaches. Therefore, in this process, the polymerization reaction at the interface and the heavy release liner in the composition layer and its vicinity (area near the interface) is easy to proceed compared to the polymerization reaction outside the area near the interface. And, at least a part of the vinyl group on the surface of the composition layer side of the heavy release liner participates in a polymerization reaction in the area near the interface and forms a chemical bond with the surface of the adhesive sheet formed in this process. Therefore, the present manufacturing method is suitable for manufacturing the above-described adhesive sheet with a release liner (the maximum stress (X) of the heavy release liner in a predetermined shear tensile test is 24N or more) of the present invention.

1 is a cross-sectional schematic diagram of one embodiment of an adhesive sheet with a release liner of the present invention.
FIG. 2 is an enlarged cross-sectional view of an end portion of the adhesive sheet with a release liner shown in FIG. 1.
3A and 3B are flowcharts of one embodiment of a method for producing a pressure-sensitive adhesive sheet with a release liner according to the present invention.
Figures 4A to 4E show a method for producing samples for shear tensile testing.
5 is a graph showing an example of the results of a shear tensile test. In this graph, the horizontal axis represents the growth amount (mm) in the surface direction (shear direction) of the heavy release liner, and the vertical axis represents the stress of the heavy release liner.
FIG. 6 is a graph plotting the measurement results of the maximum stress (

As shown in FIG. 1 , the adhesive sheet S with a release liner according to one embodiment of the present invention includes an adhesive sheet 10, a release liner 20, and a release liner 30. The adhesive sheet 10 has a first surface 11 and a second surface 12 on the opposite side to the first surface 11. The release liner 20 has a release surface 21 . The release liner 20 is in peelable contact with the first surface 11 of the adhesive sheet 10 on the release surface 21 side. The release liner 30 has a release surface 31 . The release liner 30 is in peelable contact with the second surface 12 of the adhesive sheet 10 on the release surface 31 side. That is, the adhesive sheet with a release liner (S) is provided with a release liner (20), an adhesive sheet (10), and a release liner (30) in that order in the thickness direction (H). The adhesive sheet with release liner (S) is spread in a direction perpendicular to the thickness direction (H) (plane direction (D)).

In this embodiment, the adhesive sheet 10 is an optically transparent adhesive sheet (optical adhesive sheet). In this embodiment, the adhesive sheet 10 is an inorganic adhesive sheet. In addition, the adhesive sheet 10 is, for example, an adhesive sheet disposed at a light passing location in a flexible device. Examples of flexible devices include flexible display panels. The flexible display panel has a laminated structure including elements such as a pixel panel, a polarizing film, a touch panel, and a cover film. The adhesive sheet 10 is used, for example, to bond elements included in a laminated structure during the manufacturing process of a flexible display panel.

The release liner 20 is a medium-release liner that requires a relatively large force to peel from the adhesive sheet 10, and the release liner 30 is a medium-release liner that requires a relatively small force to peel from the adhesive sheet 10. It is a light release liner. Specifically, in a peel test peeling from the adhesive sheet 10 under the conditions of 25°C, a peel angle of 180°, and a tensile speed of 300 mm/min, the peel liner 20 had a peel force greater than that of the peel liner 30. big. The method for measuring the peeling force is as described later in the Examples, more specifically. The release liner 30 (light release liner) and the release liner 20 (heavy release liner) are peeled from the adhesive sheet 10 in this order when the adhesive sheet 10 is used.

The maximum stress ( In the shear tensile test, the release liner 20 is stretched in the plane direction D with respect to the adhesive sheet 10. In addition, in the shear tensile test, the stress is measured on a 20 mm x 20 mm adhesive sheet piece of the adhesive sheet 10. The shear tensile test method is specifically as described later in the Examples. Examples of methods for adjusting the maximum stress ( Selection of the type of base polymer includes adjusting the composition of the monomers forming the base polymer. Methods for adjusting the maximum stress (X) include selection of the type of component other than the base polymer in the adhesive sheet 10 and adjustment of the compounding amount of the component. Examples of the component include a crosslinking agent, ultraviolet absorber, and silane coupling agent.

In the adhesive sheet with release liner (S), the maximum stress ( When it expands, the adhesive sheet 10 follows the expansion and is suitable for suppressing the generation of micro voids between the adhesive sheet 10 and the release liner 20. By suppressing microvoids, a decrease in the effective contact area between the adhesive sheet 10 and the release liner 20 is suppressed, and a decrease in adhesive force is suppressed. Therefore, the maximum stress ( ) is suitable for suppressing peeling. That is, the maximum stress (X) of 24 N or more is suitable for peeling the release liner 30 from the adhesive sheet 10 while suppressing peeling of the release liner 20 from the adhesive sheet 10. Specifically, it is as shown in the examples and comparative examples described later. From the viewpoint of suppressing peeling of the release liner 20 during peeling of the release liner 30, the maximum stress (X) is preferably 28 N or more, more preferably 32 N or more, further preferably 36 N or more, Particularly preferably, it is 40N or more. The maximum stress (X) is, for example, 60 N or less, 55 N or less, or 50 N or less.

The average rate of change (Y) (N/mm) from the stress of 5N to the stress of 10N in the shear tensile test of the release liner 20 preferably satisfies Y≥-1.43X+70. The average rate of change (Y) is the force (between the adhesive sheet 10 and the release liner 20) that resists dimensional change in the shear direction (plane direction (D)) of the release liner 20 with respect to the adhesive sheet 10. It is an indicator of interfacial adhesion. The fact that the average rate of change (Y) is large enough to satisfy Y ≥ -1.43 This configuration is suitable for peeling the release liner 30 from the adhesive sheet 10 while suppressing peeling of the release liner 20 from the adhesive sheet 10. Specifically, it is as shown in the examples and comparative examples described later.

The average rate of change (Y) is preferably 10 N/mm or more, more preferably 20 N, from the viewpoint of suppressing the generation of the above-mentioned microvoids and suppressing peeling of the release liner 20 when the release liner 30 is peeled. /mm or more, more preferably 24N/mm or more. In addition, the average rate of change (Y) (N/mm) preferably satisfies Y ≤ -1.43 More preferably, it is 90 N/mm or less, and even more preferably, it is 80 N/mm or less.

The maximum length (maximum length in plan view) of the release liner 20 is preferably 20 mm or more, more preferably 50 mm or more, and even more preferably 100 mm or more from the viewpoint of responding to the increase in size of adherends such as display panels. , especially preferably 200 mm or more. The maximum length of the release liner 20 is, for example, 200 cm or less, 150 cm or less, or 100 cm or less.

The peeling force F1 for peeling the release liner 20 (mid-release liner) from the adhesive sheet 10 is from the viewpoint of suppressing unintentional peeling of the release liner 20 from the adhesive sheet 10, Preferably it is 0.1 gf/25mm or more, more preferably 1 gf/25mm or more, and even more preferably 5 gf/25mm or more. The peel force (F1) is preferably 300 gf/25 mm or less, more preferably 200 gf/25 mm or less, and still more preferably 100 gf from the viewpoint of ensuring ease of peeling of the peel liner 20 from the adhesive sheet 10. /25mm or less. The peel force (F1) is a value measured by performing a peel test in which the release liner 20 is peeled from the adhesive sheet 10 under the conditions of a measurement temperature of 25°C, a peel angle of 180°, and a tensile speed of 300 mm/min. The method of measuring the peeling force (F1) is specifically as described later in the Examples. Examples of methods for adjusting the peeling force (F1) include selection of the type of base polymer in the adhesive sheet 10, adjustment of the molecular weight, and adjustment of the compounding amount. Methods for adjusting the peel force (F1) include selecting the type of component other than the base polymer in the adhesive sheet 10 and adjusting the compounding amount of the component. Examples of the component include a crosslinking agent, ultraviolet absorber, and silane coupling agent. These adjustment methods are also the same for the peeling force F2 described later. Additionally, as a method of adjusting the peel force F1, selection of the type of material forming the peel surface 21 of the peel liner 20 is also included.

The peel force F2 for peeling the release liner 30 (light release liner) from the adhesive sheet 10 is from the viewpoint of suppressing unintentional peeling of the release liner 30 from the adhesive sheet 10, Preferably it is 0.001gf/25mm or more, more preferably 0.01gf/25mm or more, and even more preferably 0.1gf/25mm or more. The peel force (F2) is preferably 10 gf/25 mm or less, more preferably 7 gf/25 mm or less, and even more preferably 5 gf/25 mm or less from the viewpoint of ensuring light peelability of the release liner 30 as a light release liner. am. The peel force (F2) is a value measured by conducting a peel test to peel the release liner 30 from the adhesive sheet 10 under the conditions of a measurement temperature of 25°C, a peel angle of 180°, and a tensile speed of 300 mm/min. The method of measuring the peeling force (F2) is specifically as described later in the Examples. A method of adjusting the peeling force F2 includes selecting the type of material forming the peeling surface 31 of the peeling liner 30.

The difference (F1-F2) between the peel force (F1) and the peel force (F2) is preferably 10 gf/25 mm or more from the viewpoint of suppressing peeling of the release liner 20 when peeling the release liner 30. More preferably, it is 20gf/25mm or more, and even more preferably, it is 30gf/25mm or more. The difference (F1-F2) is preferably 500 gf/25 mm or less, more preferably 300 gf/25 mm or less, from the viewpoint of ensuring a balanced peelability of the release liners 20 and 30 from the adhesive sheet 10. More preferably, it is 200gf/25mm or less.

The ratio (F1/F2) of the peel force (F1) to the peel force (F2) is preferably 1.1 or more, more preferably 1.1 or more, from the viewpoint of suppressing peeling of the release liner 20 during peeling of the release liner 30. Preferably it is 1.2 or more, more preferably 1.3 or more.

The shear storage modulus of the adhesive sheet 10 at 25°C is preferably 1 MPa or less, more preferably 500 kPa or less, further preferably 300 kPa or less, from the viewpoint of ensuring the softness of the adhesive sheet 10. Preferably it is 200 kPa or less, more preferably 180 kPa or less, and particularly preferably 150 kPa or less. The shear storage modulus of the adhesive sheet 10 at 25°C is preferably 5 kPa or more, more preferably 10 kPa or more, further preferably 15 kPa or more, and particularly preferred, from the viewpoint of ensuring the cohesion of the adhesive sheet 10. It is more than 20kPa. The shear storage modulus of the adhesive sheet can be measured using a dynamic viscoelasticity measuring device. As a dynamic viscoelasticity measuring device, for example, “Advanced Rheometric Expansion System” manufactured by Rheometric Scientific and “ARES-G2” manufactured by TA Instruments can be used. In the measurement, the measurement mode is shear mode, the measurement temperature range is -50°C to 150°C, the temperature increase rate is 5°C/min, and the frequency is 1Hz. The method for measuring the shear storage modulus is specifically as described later in the Examples.

The release liner 20 is, for example, a flexible transparent resin film. Examples of the material of the release liner 20 include polyester resin, polyolefin resin, polycarbonate resin, polyethersulfone resin, polyarylate resin, melamine resin, polyamide resin, cellulose resin, and polystyrene resin. there is. Examples of polyester resins include polyethylene terephthalate (PET), polybutylene terephthalate, and polyethylene naphthalate. Examples of polyolefin resins include polyethylene, polypropylene, and cycloolefin polymer (COP). As a material for the release liner 20, from the viewpoint of transparency and strength, polyester resin is preferably used, and PET is more preferably used.

The release surface 21 of the release liner 20 may be subjected to a release treatment with a release treatment agent. Examples of the peeling treatment include silicone peeling treatment, long-chain alkyl acrylate peeling treatment, and fluorine peeling treatment. As the peeling treatment, silicone peeling treatment is preferable from the viewpoint of ease of adjustment of the peeling force from the adhesive sheet 10.

The thickness of the release liner 20 is preferably 5 μm or more, more preferably 10 μm or more, and even more preferably 20 μm or more from the viewpoint of ensuring the protective function for the adhesive sheet 10. From the viewpoint of handling, the thickness of the release liner 20 is preferably 200 μm or less, more preferably 150 μm or less, and still more preferably 100 μm or less. The thickness of the release liner 20 is preferably greater than the thickness of the release liner 30.

When the release surface 21 of the release liner 20 is formed by a cured layer (silicon release layer) of a later-described silicone resin having a vinyl group, the thickness of the cured layer is such that the same layer material is used as an adhesive sheet. (10) From the viewpoint of suppressing transcription, it is preferably 0.20 μm or less, more preferably 0.15 μm or less, and even more preferably 0.10 μm or less. The thickness of the cured layer is preferably 0.05 μm or more, more preferably 0.07 μm or more, and still more preferably 0.09 μm or more from the viewpoint of easy peelability of the release liner 20.

The release liner 20 has an extended protruding end 20a in this embodiment. The extended protruding end portion 20a extends and protrudes outward from the end edge 13 of the adhesive sheet 10 in the surface direction D. The extended protruding length d1 from the end edge 13 of the extended protruding end 20a in the surface direction D (direction perpendicular to the end edge 13 in plan view) is defined by the pressure-sensitive adhesive sheet 10. From the viewpoint of ensuring ease of peeling when peeling the release liner 20 from the surface, the thickness is preferably 50 μm or more, more preferably 70 μm or more, and even more preferably 100 μm or more. The extended protrusion length d1 is preferably 100 mm or less, more preferably 70 mm or less, and even more preferably 50 mm or less from the viewpoint of reducing loss of materials used.

The release liner 30 is a flexible transparent resin film. As a material of the release liner 30, for example, the material mentioned above as a material of the release liner 20 can be mentioned. As a material for the release liner 30, from the viewpoint of transparency and strength, polyester resin is preferably used, and PET is more preferably used.

In this embodiment, the release surface 31 of the release liner 30 is subjected to a release treatment using a release treatment agent. Examples of the peeling treatment include silicone peeling treatment, long-chain alkyl acrylate peeling treatment, and fluorine peeling treatment. As the peeling treatment, silicone peeling treatment is preferable from the viewpoint of ease of adjustment of the peeling force from the adhesive sheet 10. The peeling treatment for the release liner 30 is performed so that the peeling force F2 of the peeling liner 30 is smaller than the peeling force F1 of the peeling liner 20.

The thickness of the release liner 30 is preferably 5 μm or more, more preferably 10 μm or more, and even more preferably 20 μm or more from the viewpoint of ensuring the protective function for the adhesive sheet 10. From the viewpoint of handling, the thickness of the release liner 30 is preferably 200 μm or less, more preferably 150 μm or less, and still more preferably 100 μm or less.

The release liner 30 has an extended protruding end 30a in this embodiment. The extended protruding end portion 30a extends and protrudes outward from the end edge 13 of the adhesive sheet 10 in the surface direction D. The extended protruding length d2 from the end edge 13 of the extended protruding end 30a in the surface direction D (direction perpendicular to the end edge 13 in plan view) is defined by the pressure-sensitive adhesive sheet 10. From the viewpoint of ensuring ease of peeling when peeling the release liner 30 from the surface, the thickness is preferably 50 μm or more, more preferably 70 μm or more, and even more preferably 100 μm or more. The extended protrusion length d2 is preferably 100 mm or less, more preferably 70 mm or less, and even more preferably 50 mm or less from the viewpoint of reducing loss of materials used. The extended protruding length d2 is preferably longer than the above-described extended protruding length d1 from the viewpoint of suppressing peeling of the release liner 20 when peeling the release liner 30 from the adhesive sheet 10. . From the viewpoint of suppressing peeling of the release liner 20 when peeling the release liner 30 from the adhesive sheet 10, the difference (d2-d1) between the extended protruding length d2 and the extended protruding length d1 is , preferably 100 μm or more, more preferably 500 μm or more, and even more preferably 1000 μm or more. The difference (d2-d1) is, for example, 50 mm or less.

The adhesive sheet 10 is a sheet-shaped pressure-sensitive adhesive formed of an adhesive composition. The adhesive sheet 10 (adhesive composition) contains at least a base polymer.

The base polymer is an adhesive component that causes the adhesive sheet 10 to exhibit adhesiveness. Base polymers include, for example, acrylic polymer, silicone polymer, polyester polymer, polyurethane polymer, polyamide polymer, polyvinyl ether polymer, vinyl acetate/vinyl chloride copolymer, modified polyolefin polymer, epoxy polymer, fluorine polymer, and rubber polymer. can be mentioned. The base polymer may be used individually, or two or more types may be used together. From the viewpoint of ensuring good transparency and adhesion in the adhesive sheet 10, an acrylic polymer is preferably used as the base polymer.

Acrylic polymer is a copolymer of a monomer component containing (meth)acrylic acid ester in a proportion of 50% by mass or more. “(meth)acrylic” means acrylic and/or methacryl.

As the (meth)acrylic acid ester, a (meth)acrylic acid alkyl ester is preferably used, and more preferably, a (meth)acrylic acid alkyl ester whose alkyl group has 1 to 20 carbon atoms is used. The (meth)acrylic acid alkyl ester may have a linear or branched alkyl group, or may have a cyclic alkyl group such as an alicyclic alkyl group.

Examples of (meth)acrylic acid alkyl esters having a linear or branched alkyl group include methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, and (meth)acrylic acid. -Butyl, t-butyl (meth)acrylate, pentyl (meth)acrylate, isopentyl (meth)acrylate, neopentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, 2-ethyl (meth)acrylate Hexyl, octyl (meth)acrylate, isooctyl (meth)acrylate, nonyl (meth)acrylate, isononyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, undecyl (meth)acrylate, ( Dodecyl (meth)acrylate, isotridecyl (meth)acrylate, tetradecyl (meth)acrylate, isotetradecyl (meth)acrylate, pentadecyl (meth)acrylate, cetyl (meth)acrylate, heptadecyl (meth)acrylate, Examples include stearyl (meth)acrylate, isostearyl (meth)acrylate, and nonadecyl (meth)acrylate.

Examples of (meth)acrylic acid alkyl esters having an alicyclic alkyl group include (meth)acrylic acid cycloalkyl esters, (meth)acrylic acid esters having a bicyclic aliphatic hydrocarbon ring, and (meth)acrylic acid esters having a tricyclic or more aliphatic hydrocarbon ring. Acrylic acid ester can be mentioned. Examples of (meth)acrylic acid cycloalkyl esters include cyclopentyl (meth)acrylate, cyclohexyl (meth)acrylate, cycloheptyl (meth)acrylate, and cyclooctyl (meth)acrylate. Examples of (meth)acrylic acid esters having a bicyclic aliphatic hydrocarbon ring include isobornyl (meth)acrylate. Examples of (meth)acrylic acid esters having three or more aliphatic hydrocarbon rings include dicyclopentanyl (meth)acrylate, dicyclopentanyloxyethyl (meth)acrylate, tricyclofentanyl (meth)acrylate, and 1-acrylate. Damantyl (meth)acrylate, 2-methyl-2-adamantyl (meth)acrylate, and 2-ethyl-2-adamantyl (meth)acrylate can be mentioned.

As the (meth)acrylic acid alkyl ester, acrylic acid alkyl ester having an alkyl group having 3 to 15 carbon atoms is preferably used, and more preferably, acrylic acid n-butyl (BA), 2-ethylhexyl acrylate (2EHA), and acrylic acid isoste are used. At least one selected from the group consisting of aryl (ISTA) and cyclohexyl acrylate (CHA) is used.

The proportion of (meth)acrylic acid alkyl ester in the monomer component is preferably 50% by mass or more, more preferably 70% by mass, from the viewpoint of appropriately expressing basic properties such as adhesiveness in the adhesive sheet 10. or more, more preferably 80 mass% or more, particularly preferably 85 mass% or more. The ratio is, for example, 99% by mass or less.

The monomer component may contain a copolymerizable monomer that can be copolymerized with an alkyl (meth)acrylate ester. Examples of copolymerizable monomers include monomers having a polar group. Examples of polar group-containing monomers include hydroxy group-containing monomers, carboxyl group-containing monomers, and monomers having a nitrogen atom-containing ring. The polar group-containing monomer is helpful in modifying the acrylic polymer, such as introducing crosslinking points into the acrylic polymer and securing the cohesion of the acrylic polymer.

Examples of hydroxy group-containing monomers include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, and (meth)acrylic acid. ) 4-hydroxybutyl acrylic acid, 6-hydroxyhexyl (meth)acrylic acid, 8-hydroxyoctyl (meth)acrylic acid, 10-hydroxydecyl (meth)acrylic acid, 12-hydroxylauryl (meth)acrylic acid, and ( and 4-hydroxymethylcyclohexyl)methyl (meth)acrylate. As the hydroxy group-containing monomer, at least one selected from the group consisting of 2-hydroxyethyl acrylate (HEA) and 4-hydroxybutyl acrylate (4HBA) is preferably used.

The proportion of the hydroxy group-containing monomer in the monomer component is preferably 1% by mass or more, more preferably 3% by mass or more from the viewpoint of introducing a crosslinked structure into the acrylic polymer and ensuring cohesion in the adhesive sheet. , more preferably 5% by mass or more. The ratio is preferably 35% by mass or less, more preferably 32% by mass or less, from the viewpoint of adjusting the polarity of the acrylic polymer (related to compatibility between various additive components in the adhesive sheet and the acrylic polymer). .

Examples of the carboxyl group-containing monomer include acrylic acid, methacrylic acid, carboxyethyl acrylate, carboxypentyl acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid, and isocrotonic acid.

The ratio of the carboxyl group-containing monomer in the monomer component is preferably 0.1 mass from the viewpoints of introducing a crosslinked structure into the acrylic polymer, ensuring cohesion in the adhesive sheet, and ensuring adhesion to the main adhesive in the adhesive sheet. % or more, more preferably 0.5 mass% or more, and even more preferably 0.8 mass% or more. The ratio is preferably 10% by mass or less, more preferably 5% by mass or less, from the viewpoint of adjusting the glass transition temperature of the acrylic polymer and avoiding the risk of corrosion of the adherend due to acid.

Examples of monomers having a nitrogen atom-containing ring include N-vinyl-2-pyrrolidone, N-methylvinylpyrrolidone, N-vinylpyridine, N-vinylpiperidone, N-vinylpyrimidine, and N-vinylpyrrolidone. Piperazine, N-vinylpyrazine, N-vinylpyrrole, N-vinylimidazole, N-vinyloxazole, N-(meth)acryloyl-2-pyrrolidone, N-(meth)acryloylpiperi Dean, N-(meth)acryloylpyrrolidine, N-vinylmorpholine, N-vinyl-3-morpholinone, N-vinyl-2-caprolactam, N-vinyl-1,3-oxazine-2 -one, N-vinyl-3,5-morpholinedione, N-vinylpyrazole, N-vinylisoxazole, N-vinylthiazole, and N-vinylisothiazole. As the monomer having a nitrogen atom-containing ring, N-vinyl-2-pyrrolidone (NVP) is preferably used.

The proportion of the monomer having a nitrogen atom-containing ring in the monomer component is preferably 1% by mass or more, from the viewpoint of ensuring cohesion in the adhesive sheet and ensuring adhesion to the main adhesive in the adhesive sheet. Preferably it is 3% by mass or more, more preferably 5% by mass or more. The ratio is preferably 35% by mass or less from the viewpoint of adjusting the glass transition temperature of the acrylic polymer and adjusting the polarity of the acrylic polymer (related to compatibility between various additive components in the adhesive sheet and the acrylic polymer). , more preferably 30 mass% or less, even more preferably 25 mass% or less.

The monomer component may contain other copolymerizable monomers. Other copolymerizable monomers include, for example, acid anhydride monomers, sulfonic acid group-containing monomers, phosphoric acid group-containing monomers, epoxy group-containing monomers, cyano group-containing monomers, alkoxy group-containing monomers, and aromatic vinyl compounds. These other copolymerizable monomers may be used individually, or two or more types may be used together.

The base polymer can be formed, for example, by photopolymerizing the monomer component described above. Examples of photopolymerization include photopolymerization by ultraviolet irradiation. As a polymerization initiator, a photopolymerization initiator is used.

Examples of the photopolymerization initiator include a radical photopolymerization initiator, a cationic photopolymerization initiator, and an anionic photopolymerization initiator.

Examples of the radical photopolymerization initiator include acylphosphine oxide photopolymerization initiator, benzoin ether photopolymerization initiator, acetophenone photopolymerization initiator, α-ketol photopolymerization initiator, aromatic sulfonyl chloride photopolymerization initiator, photoactive oxime photopolymerization initiator, and benzoin photopolymerization initiator. You can.

Examples of the acylphosphine oxide photopolymerization initiator include bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide and bis(2,4,6-trimethylbenzoyl)-2,4-di-n-butoxyphenyl. Phosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, and bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide are included. Examples of the benzoin ether photopolymerization initiator include benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzoin isopropyl ether, benzoin isobutyl ether, and 2,2-dimethoxy-1,2-diphenyl. Ethane-1-one may be mentioned. Acetophenone photopolymerization initiators include, for example, 2,2-diethoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 1-hydroxycyclohexylphenyl ketone, 4-phenoxydichloroacetophenone, and 4- (t-butyl)dichloroacetophenone can be mentioned. Examples of the α-ketol photopolymerization initiator include 2-methyl-2-hydroxypropiophenone and 1-[4-(2-hydroxyethyl)phenyl]-2-methylpropan-1-one. Examples of the aromatic sulfonyl chloride photopolymerization initiator include 2-naphthalenesulfonyl chloride. Examples of the photoactive oxime photopolymerization initiator include 1-phenyl-1,1-propanedione-2-(o-ethoxycarbonyl)-oxime. Examples of the benzoin photopolymerization initiator include benzoin. The photopolymerization initiator may be used individually, or two or more types may be used together.

The amount of the photopolymerization initiator used (when using multiple photopolymerization initiators, the total amount of the multiple photopolymerization initiators) is, for example, 0.05 parts by mass or more, preferably 0.10 parts by mass or more, more preferably 0.10 parts by mass or more, based on 100 parts by mass of the monomer component. is 0.15 parts by mass or more, more preferably 0.20 parts by mass or more, and is also, for example, 1 part by mass or less, preferably 0.80 parts by mass or less, more preferably 0.70 parts by mass or less, even more preferably 0.60 parts by mass. It is as follows.

Acrylic polymer may be polymerized using other polymerization methods. Other polymerization methods include, for example, solution polymerization, bulk polymerization, and emulsion polymerization. As solvents for solution polymerization, for example, ethyl acetate and toluene are used. In addition, as a polymerization initiator, a thermal polymerization initiator and the photo-polymerization initiator described above may be used. The amount of the polymerization initiator used is, for example, 0.05 parts by mass or more, and for example, 1 part by mass or less, per 100 parts by mass of the monomer component.

Examples of thermal polymerization initiators include azo polymerization initiators and peroxide polymerization initiators. Examples of the azo polymerization initiator include 2,2'-azobisisobutyronitrile, 2,2'-azobis-2-methylbutyronitrile, 2,2'-azobis(2-methylpropionic acid)dimethyl, 4,4'-azobis-4-cyanovaleric acid, azobisisovaleronitrile, 2,2'-azobis(2-amidinopropane)dihydrochloride, 2,2'-azobis[2- (5-methyl-2-imidazolin-2-yl)propane]dihydrochloride, 2,2'-azobis(2-methylpropionamidine) disulfate, and 2,2'-azobis(N, N'-dimethyleneisobutylamidine)dihydrochloride can be mentioned. Examples of peroxide polymerization initiators include dibenzoyl peroxide, t-butyl permaleate, and lauroyl peroxide.

The base polymer preferably has a crosslinked structure. Examples of methods for introducing a crosslinked structure into the base polymer include the following first and second methods. In the first method, a base polymer having a functional group capable of reacting with the crosslinking agent and a crosslinking agent are blended into an adhesive composition, and the base polymer and the crosslinking agent are reacted in an adhesive sheet. In the second method, the monomer component forming the base polymer includes a polyfunctional compound such as a polyfunctional monomer, and polymerization of the monomer component forms a base polymer in which a branched structure (cross-linked structure) is introduced into the polymer chain. . These methods may be used together.

Examples of the crosslinking agent used in the first method include compounds that react with functional groups (such as hydroxy groups and carboxyl groups) contained in the base polymer. Examples of such crosslinking agents include isocyanate crosslinking agents, peroxide crosslinking agents, epoxy crosslinking agents, oxazoline crosslinking agents, aziridine crosslinking agents, carbodiimide crosslinking agents, and metal chelate crosslinking agents. The crosslinking agent may be used individually, or two or more types may be used together. As the crosslinking agent, an isocyanate crosslinking agent, a peroxide crosslinking agent, and an epoxy crosslinking agent are preferably used because they have high reactivity with the hydroxy groups and carboxyl groups in the base polymer, making it easy to introduce a crosslinking structure.

Isocyanate crosslinking agents include, for example, tolylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate, and tetramethylene diisocyanate. Examples include silylene diisocyanate, naphthalene diisocyanate, triphenylmethane triisocyanate, and polymethylene polyphenylisocyanate. Additionally, examples of the isocyanate crosslinking agent include derivatives of these isocyanates. Examples of the isocyanate derivative include isocyanurate modified products and polyol modified products. Commercially available isocyanate crosslinking agents include, for example, Coronate L (trimethylolpropane adduct of tolylene diisocyanate, coating agent), Coronate HL (trimethylolpropane adduct of hexamethylene diisocyanate, coating agent), Coronate HX (isocyanurate form of hexamethylene diisocyanate, coated product), Takenate D110N (trimethylolpropane adduct form of xylylene diisocyanate, manufactured by Mitsui Chemicals), and Takenate 600 (1,3-bis(iso) cyanatomethyl) cyclohexane, manufactured by Mitsui Chemicals).

As peroxide crosslinking agents, dibenzoyl peroxide, di(2-ethylhexyl)peroxydicarbonate, di(4-t-butylcyclohexyl)peroxydicarbonate, di-sec-butylperoxydicarbonate, t -Butylperoxyneodecanoate, t-hexylperoxypivalate, and t-butylperoxypivalate.

As an epoxy crosslinking agent, bisphenol A, epichlorohydrin type epoxy resin, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, glycerin diglycidyl ether, glycerol triglycidyl ether, 1,6-hexane. Diol glycidyl ether, trimethylolpropane triglycidyl ether, diglycidyl aniline, diamine glycidyl amine, N, N, N', N'-tetraglycidyl-m-xylylenediamine and 1, and 3-bis(N,N-diglycidylaminomethyl)cyclohexane.

Isocyanate crosslinking agents (especially bifunctional isocyanate crosslinking agents) and peroxide crosslinking agents are preferable from the viewpoint of ensuring the flexibility of the adhesive sheet 10. An isocyanate crosslinking agent (particularly a trifunctional isocyanate crosslinking agent) is preferable from the viewpoint of ensuring the durability of the adhesive sheet 10. In the base polymer, the bifunctional isocyanate crosslinking agent and the peroxide crosslinking agent form a more flexible two-dimensional crosslinking, while the trifunctional isocyanate crosslinking agent forms a more rigid three-dimensional crosslinking. From the viewpoint of both durability and flexibility of the adhesive sheet 10, combined use of a trifunctional isocyanate crosslinking agent, a peroxide crosslinking agent, and/or a bifunctional isocyanate crosslinking agent is preferable.

The compounding amount of the crosslinking agent in the first method is preferably 0.01 parts by mass or more, more preferably 0.02 parts by mass or more, with respect to 100 parts by mass of the base polymer, from the viewpoint of ensuring the cohesion of the adhesive sheet 10. More preferably, it is 0.05 parts by mass or more. The amount of the crosslinking agent in the first method is preferably 3 parts by mass or less, more preferably 1 part by mass, per 100 parts by mass of the base polymer from the viewpoint of ensuring good adhesion in the adhesive sheet 10. or less, more preferably 0.5 parts by mass or less.

In the second method, polyfunctional compounds such as monofunctional monomers and polyfunctional monomers for introducing a crosslinked structure may be polymerized at once or may be polymerized in multiple steps. In the multi-step polymerization method, first, monofunctional monomers are polymerized (pre-polymerization), thereby preparing a prepolymer composition containing a partially polymerized product (a mixture of a low-polymerized product and an unreacted monomer). Next, a polyfunctional compound (polyfunctional monomer may be sufficient) as a crosslinking agent is added to the prepolymer composition, and then the partially polymerized product and the polyfunctional compound are polymerized (main polymerization).

Examples of polyfunctional compounds include polyfunctional monomers and polyfunctional oligomers containing two or more ethylenically unsaturated double bonds per molecule. Examples of polyfunctional monomers include polyfunctional (meth)acrylate.

Examples of polyfunctional (meth)acrylates include bifunctional (meth)acrylates, trifunctional (meth)acrylates, and tetrafunctional or higher polyfunctional (meth)acrylates.

Examples of bifunctional (meth)acrylates include ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, and tetraethylene glycol di(meth)acrylate. , 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, glycerin di(meth)acrylate, ethoxylated bisphenol A diacrylate (BPAEODE) and neopentyl glycol diacrylate. (meth)acrylate can be mentioned.

Examples of the trifunctional (meth)acrylate include trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, and tris(acryloyloxyethyl)isocyanurate.

Examples of tetrafunctional or higher polyfunctional (meth)acrylates include ditrimethylolpropane tetra(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol monohydroxypenta(meth)acrylate, Alkyl-modified dipentaerythritol penta(meth)acrylate and dipentaerythritol hexa(meth)acrylate can be mentioned.

Examples of the multifunctional oligomer include urethane (meth)acrylate oligomer, polyester (meth)acrylate oligomer, polyether (meth)acrylate oligomer, polyol (meth)acrylate oligomer, epoxy (meth)acrylate oligomer, Examples include polyethylene glycol di(meth)acrylate and polypropylene glycol di(meth)acrylate.

The polyfunctional compound as a crosslinking agent in the second method may be used individually, or two or more types may be used together. The multifunctional compound is preferably 1,6-hexanediol diacrylate (HDDA), dipentaerythritol hexaacrylate (DPHA), trimethylolpropane triacrylate (TMPTA), and urethane acrylate oligomer (UAO). At least one selected from the group consisting of is used.

When using a polyfunctional monomer as a polyfunctional compound, the compounding amount of the polyfunctional monomer in the monomer component is per 100 parts by mass of the monofunctional monomer, preferably 0.01 part by mass, from the viewpoint of ensuring the cohesion of the adhesive sheet 10. or more, more preferably 0.02 parts by mass or more, and even more preferably 0.05 parts by mass or more. From the viewpoint of ensuring good adhesion in the adhesive sheet 10, the amount of the polyfunctional monomer is preferably 3 parts by mass or less, more preferably 2 parts by mass or less, per 100 parts by mass of the monofunctional monomer. It is 1 part by mass or less.

When using a polyfunctional oligomer as a polyfunctional compound, the compounding amount of the polyfunctional oligomer in the monomer component is per 100 parts by mass of the monofunctional monomer, preferably 0.2 parts by mass, from the viewpoint of ensuring the cohesion of the adhesive sheet 10. or more, more preferably 0.5 parts by mass or more, and even more preferably 0.7 parts by mass or more. From the viewpoint of ensuring good adhesion in the pressure-sensitive adhesive sheet 10, the amount of the polyfunctional oligomer is preferably 8 parts by mass or less, more preferably 5 parts by mass or less, per 100 parts by mass of the monofunctional monomer. It is 3 parts by mass or less.

In polymerization, a chain transfer agent may be used for purposes such as molecular weight adjustment. As chain transfer agents, α-thioglycerol, lauryl mercaptan, glycidyl mercaptan, mercaptoacetic acid, 2-mercaptoethanol, thioglycolic acid, 2-ethylhexyl thioglycolic acid, 2,3-dimercapto-1- Propanol and α-methylstyrene dimer are included.

The weight average molecular weight of the base polymer is preferably 100,000 or more, more preferably 300,000 or more, and still more preferably 500,000 or more from the viewpoint of ensuring cohesion in the adhesive sheet 10. The weight average molecular weight of the base polymer is measured by gel permeation chromatography (GPC) and calculated by conversion to polystyrene.

The glass transition temperature (Tg) of the base polymer is preferably 0°C or lower, more preferably -10°C or lower, and even more preferably -20°C or lower. The glass transition temperature is, for example, -80°C or higher.

For the glass transition temperature (Tg) of the base polymer, the glass transition temperature (theoretical value) determined based on Fox's equation below can be used. Fox's equation is a relationship between the glass transition temperature (Tg) of a polymer and the homopolymer glass transition temperature (Tgi) of the monomer constituting the polymer. In the formula of Fox below, Tg represents the glass transition temperature (°C) of the polymer, Wi represents the weight fraction of monomer (i) constituting the polymer, and Tgi is the homopolymer formed from monomer (i). Indicates the glass transition temperature (°C). Literature values can be used for the glass transition temperature of homopolymers. For example, “Polymer Handbook” (4th edition, John Wiley & Sons, Inc., 1999) provides examples of the glass transition temperatures of various homopolymers. On the other hand, the homopolymer glass transition temperature of the monomer can also be determined by the method specifically described in Japanese Patent Application Laid-Open No. 2007-51271.

Fox's expression 1/(273+Tg)=Σ[Wi/(273+Tgi)]

The adhesive composition may contain an ultraviolet absorber. Examples of ultraviolet absorbers include triazine ultraviolet absorbers, benzotriazole ultraviolet absorbers, benzophenone ultraviolet absorbers, salicylate ultraviolet absorbers, and cyanoacrylate ultraviolet absorbers. The ultraviolet absorber may be used individually, or two or more types may be used together.

Commercially available triazine ultraviolet absorbers include, for example, bisethylhexoxyoxyphenolmethoxyphenyltriazine (product name “Tinosorb S”, manufactured by BASF), 2-(4,6-bis(2,4-dimethylphenyl)- Reaction product of 1,3,5-triazin-2-yl)-5-hydroxyphenyl and [(alkyloxy)methyl]oxirane (product name “TINUVIN 400”, manufactured by BASF), 2-(2,4 -Dihydroxyphenyl)-4,6-bis-(2,4-dimethylphenyl)-1,3,5-triazine and (2-ethylhexyl)-glycidic acid ester reaction product (product name “TINUVIN 405”) ", manufactured by BASF), (2,4-bis[2-hydroxy-4-butoxyphenyl]-6-(2,4-dibutoxyphenyl)-1,3,5-triazine (product name "TINUVIN 460 ", manufactured by BASF), 2-(4,6-diphenyl-1,3,5-triazin-2-yl)-5-[(hexyl)oxy]-phenol (product name "TINUVIN 577", manufactured by BASF) , 2-(2-hydroxy-4-[1-octyloxycarbonylethoxy]phenyl)-4,6-bis(4-phenylphenyl)-1,3,5-triazine (product name “TINUVIN 479”) , manufactured by BASF) and 2-(4,6-diphenyl-1,3,5-triazin-2-yl)-5-[2-(2-ethylhexanoyloxy)ethoxy]-phenol (「 ADK STAB LA-46”, manufactured by ADEKA).

Commercially available benzotriazole ultraviolet absorbers include, for example, 2-(2H-benzotriazol-2-yl)-6-(1-methyl-1-phenylethyl)-4-(1,1,3,3- Tetramethylbutyl)phenol (product name “TINUVIN 928”, manufactured by BASF), 2-(2-hydroxy-5-tert-butylphenyl)-2H-benzotriazole (product name “TINUVIN PS”, manufactured by BASF), 2- (2H-benzotriazol-2-yl)-4,6-bis(1-methyl-1-phenylethyl)phenol (product name “TINUVIN 900”, manufactured by BASF), 2-(2H-benzotriazole-2- 1)-6-(1-methyl-1-phenylethyl)-4-(1,1,3,3-tetramethylbutyl)phenol (product name “TINUVIN 928”, manufactured by BASF), 2-(2H-Benzotria) Zol-2-yl)-6-dodecyl-4-methylphenol (product name “TINUVIN571”, manufactured by BASF), 2-(2H-benzotriazol-2-yl)-p-cresol (product name “TINUVIN P”, BASF), 2-(2H-benzotriazol-2-yl)-4-6-bis(1-methyl-1-phenylethyl)phenol (product name “TINUVIN 234”, BASF), 2-[5- Chloro(2H)-benzotriazol-2-yl]-4-methyl-6-(tert-butyl)phenol (product name “TINUVIN 326”, manufactured by BASF), 2-(2H-benzotriazol-2-yl) -4,6-di-tert-pentylphenol (product name “TINUVIN 328”, manufactured by BASF), 2-(2H-benzotriazol-2-yl)-4-(1,1,3,3-tetramethylbutyl ) Phenol (product name “TINUVIN 329”, manufactured by BASF) and 2-[2-hydroxy-3-(3,4,5,6-tetrahydrophthalimidomethyl)-5-methylphenyl]benzotriazole (product name “ Sumisorb250”, manufactured by Sumitomo Chemical).

The ultraviolet absorber is preferably a triazine ultraviolet absorber, and more preferably is bisethylhexoxyoxyphenolmethoxyphenyltriazine.

The adhesive composition may contain a silane coupling agent. The content of the silane coupling agent in the adhesive composition is preferably 0.1 parts by mass or more, more preferably 0.2 parts by mass or more, based on 100 parts by mass of the base polymer. The copper content is preferably 5 parts by mass or less, more preferably 3 parts by mass or less.

The adhesive composition may contain other components as needed. Other components include, for example, tackifiers, plasticizers, softeners, antioxidants, surfactants, and antistatic agents.

The adhesive composition may be a photopolymerizable adhesive composition containing an ultraviolet absorber. That is, the adhesive sheet 10 may be a photocured product of a photopolymerizable adhesive composition containing an ultraviolet absorber.

The thickness of the adhesive sheet 10 is preferably 10 μm or more, more preferably 20 μm or more, and even more preferably 30 μm or more from the viewpoint of ensuring sufficient adhesion to the adherend. The thickness of the adhesive sheet 10 is preferably 500 μm or less, more preferably 300 μm or less, further preferably 250 μm or less, even more preferably 200 μm or less, from the viewpoint of thinning the device in which the adhesive sheet 10 is used. More preferably, it is 150 μm or less, and particularly preferably, it is 100 μm or less.

The haze of the adhesive sheet 10 is preferably 3% or less, more preferably 2% or less, and still more preferably 1% or less. The haze of the adhesive sheet 10 can be measured using a haze meter based on JIS K7136 (2000). Examples of the haze meter include "NDH2000" manufactured by Nippon Denshoku Kogyo Co., Ltd. and "HM-150N" manufactured by Murakami Shikisai Kijutsu Kenkyujo Co., Ltd. The haze measurement method is specifically as described later in the Examples.

The adhesive sheet with release liner (S) can be manufactured, for example, as follows.

First, prepare the release liner 20 (medium release liner) and the release liner 30 (light release liner).

Next, the above-described adhesive composition is applied on the release liner 20 to form a coating film, and then the coating film is dried. Application methods of the adhesive composition include, for example, roll coat, kiss roll coat, gravure coat, reverse coat, roll brush, spray coat, dip roll coat, bar coat, knife coat, air knife coat, curtain coat, lip coat, and A die coat may be used. The drying temperature of the coating film is, for example, 50°C to 200°C. Drying time is, for example, 5 seconds to 20 minutes.

Next, the release liner 30 is bonded onto the coating film on the release liner 20. Thereafter, the coating film is aged as necessary. The aging temperature is, for example, 20°C to 160°C. Aging time is, for example, from 1 minute to 21 days. Additionally, the coating film is irradiated with light as necessary. Examples of light sources for light irradiation include ultraviolet LED lights, high-pressure mercury lamps, and metal halide lamps.

As described above, the pressure-sensitive adhesive sheet (S) with a release liner may be manufactured.

3A and 3B are process diagrams of one embodiment of the method for producing a pressure-sensitive adhesive sheet with a release liner according to the present invention. This manufacturing method is a manufacturing method when the above-described pressure-sensitive adhesive composition for forming the pressure-sensitive adhesive sheet 10 is a photopolymerizable pressure-sensitive adhesive composition containing an ultraviolet absorber. This manufacturing method includes a preparation process (FIG. 3A) and an adhesive sheet forming process (FIG. 3B).

In the preparation process, laminated film S' is prepared, as shown in FIG. 3A. The laminated film S' is provided with a release liner 20 (heavy release liner), a composition layer 10', and a release liner 30 (light release liner) in this order in the thickness direction (H). . The composition layer 10' is formed of the above-described photopolymerizable adhesive composition containing an ultraviolet absorber. The laminated film (S') is formed, for example, by applying a photopolymerizable adhesive composition on the release liner 20 to form a coating film, and then bonding the release liner 30 onto the coating film on the release liner 20, It can be produced. The laminated film (S') can also be produced by applying a photopolymerizable adhesive composition on the release liner 30 to form a coating film, and then bonding the release liner 20 onto the coating film on the release liner 30. Application methods of the photopolymerizable adhesive composition include, for example, roll coat, kiss roll coat, gravure coat, reverse coat, roll brush, spray coat, dip roll coat, bar coat, knife coat, air knife coat, curtain coat, and lip. These include coats and die coats.

The release liner 20 has a vinyl group on the surface (release surface 21) on the composition layer 10' side. Such a release liner 20 can be produced, for example, by forming a cured layer of a silicone resin having a vinyl group (silicon release layer) on the surface of the above-mentioned resin film. Examples of the silicone resin having a vinyl group include organopolysiloxane having a vinyl group. Commercially available silicone resins having a vinyl group include, for example, “LTC761,” “SRX290,” and “SRX244” manufactured by Toray Dow Corning, and “KS-847H” and “KM-3951” manufactured by Shin-Etsu Chemical. , “X-52-151”, “X-52-6068”, and “X-52-6069”.

Next, in the adhesive sheet forming step, as shown in FIG. 3B, ultraviolet rays (schematically shown by an upward arrow in the figure) are irradiated from the release liner 20 side to the laminated film S', The composition layer 10' (photopolymerizable adhesive composition) is photocured to form the adhesive sheet 10. Examples of ultraviolet light sources include ultraviolet LED lights, high-pressure mercury lamps, black lights, and metal halide lamps. By ultraviolet irradiation, the polymerization reaction of the above-mentioned monomer component in the photopolymerizable adhesive composition proceeds in the composition layer 10'. When producing an adhesive sheet with a thickness of, for example, about 100 μm, the illuminance of ultraviolet rays is preferably 0.1 mW/cm ² or more, more preferably 1.0 mW/cm ² or more from the viewpoint of sufficiently advancing the polymerization reaction. . From the viewpoint of sufficiently advancing the polymerization reaction, the cumulative amount of ultraviolet rays is preferably 500 mJ/cm ² or more, more preferably 1000 mJ/cm ² or more. The amount of irradiated integrated light may be adjusted (increased or decreased) according to the amount of the composition to be cured, that is, according to the thickness of the adhesive sheet after curing.

As described above, the pressure-sensitive adhesive sheet (S) with a release liner may be manufactured.

In the adhesive sheet forming process (FIG. 3b) of the present manufacturing method, as described above, ultraviolet rays are irradiated from the release liner 20 (mid-release liner) side with respect to the laminated film S' to form the composition layer 10'. It becomes photogenic. Since the photopolymerizable adhesive composition forming the composition layer 10' contains an ultraviolet absorber, the ultraviolet rays incident on the composition layer 10' from the release liner 20 side are converted into ultraviolet rays in the composition layer 10'. While attenuating due to absorption by the absorbent, it reaches the release liner 30 (light release liner) side. Therefore, in this process, the polymerization reaction at the interface of the composition layer 10' with the release liner 20 and its vicinity (region near the interface) proceeds at a slower rate compared to the polymerization reaction outside the region near the interface. easy to do. In addition, at least a part of the vinyl groups on the surface (release surface 21) on the composition layer 10' side of the release liner 20 are involved in a polymerization reaction in the region near the interface, and are formed in this process. Forms a chemical bond with the surface of the adhesive sheet 10. Therefore, this manufacturing method is suitable for manufacturing the above-described adhesive sheet with release liner (S) (maximum stress (X) of the release liner 20 in the shear tensile test is 24 N or more).

[Example]

The present invention will be described in detail below by giving examples. However, the present invention is not limited to the examples. In addition, the specific values of the mixing amount (content), physical property values, parameters, etc. described below are the corresponding mixing amounts (content), physical property values, parameters, etc. described in the above-mentioned "Mode for Carrying out the Invention". It can be replaced with the upper limit (a numerical value defined as “less than” or “less than”) or the lower limit (a numerical value defined as “more than” or “exceeds”).

<Production of the first heavy release liner>

100 parts by mass of a silicone-based release treatment agent (product name “KS-847H”, manufactured by Shin-Etsu Chemical Industries, Ltd.), and 1.0 parts by mass of a platinum catalyst for silicone curing (product name “CAT-PL-50T”, manufactured by Shin-Etsu Chemical Industries, Ltd.) and a solvent were mixed to prepare a first release treatment agent solution with a silicon solid content concentration of 1.25% by mass. The solvent is a mixed solvent of toluene and hexane in a volume ratio of 1:1.

Next, a biaxially stretched polyester film (product name “Lumirror Specifically, first, the above-mentioned first peeling agent solution was applied to one side of the base film to form a coating film. For application, wire bar #9 was used. Next, the coating film on the base film was dried by heating at 130°C for 1 minute using a hot air dryer. In this way, a silicone release layer with a thickness of 0.10 μm was formed on the base film.

As described above, the first heavy release liner was produced. The first heavy release liner has a laminated structure of a base film and a release layer (thickness 0.10 μm).

<Production of the second heavy release liner>

Silicone-based release treatment agent (product name “KE-3703”, a 28.5% by mass toluene solution of an addition-type silicone-based release treatment agent containing a polyorganosiloxane having a hexenyl group in the molecule and a polyorganosiloxane crosslinking agent having a hydrosilyl group in the molecule, Shin 80 parts by mass of a silicone-based peeling control agent (product name “KS-3800”, manufactured by Shin-Etsu Chemical Industries, Ltd.), and 20 parts by mass of a platinum catalyst for silicone curing (product name “CAT-PL-50T”) ", manufactured by Shin-Etsu Chemical Co., Ltd.) and a solvent were mixed to prepare a second peeling treatment agent solution with a silicon solid content concentration of 1.25 mass%. The solvent is a mixed solvent of toluene and hexane in a volume ratio of 1:1.

Next, a biaxially stretched polyester film (product name “Lumirror Specifically, first, the above-mentioned second peeling agent solution was applied to one side of the base film to form a coating film. For application, wire bar #9 was used. Next, the coating film on the base film was dried by heating at 130°C for 1 minute using a hot air dryer. In this way, a silicone release layer with a thickness of 0.13 μm was formed on the base film.

<Production of the third heavy release liner>

100 parts by mass of a silicone-based peeling treatment agent (product name “KE-3703”, manufactured by Shin-Etsu Chemical Industries, Ltd.), and 9.0 parts by mass of a silicone-based peeling control agent (product name “X-92-183”, manufactured by Shin-Etsu Chemical Industries, Ltd.) , 6.0 parts by mass of a platinum catalyst for silicon curing (product name "CAT-PL-50T", manufactured by Shin-Etsu Chemical Co., Ltd.) and a solvent were mixed to prepare a third stripping treatment agent solution with a silicon solid content concentration of 1.0 mass%. The solvent is a mixed solvent of toluene and hexane in a volume ratio of 1:1. Then, the base film (Lumirror A third heavy release liner was produced.

<Manufacture of the fourth heavy release liner>

Silicone-based release treatment agent (product name “LTC761”, a 30% by mass toluene solution of an addition-type silicone-based release treatment agent containing a polyorganosiloxane having a 5-hexenyl group in the molecule and a polyorganosiloxane crosslinking agent having a hydrosilyl group in the molecule, Toray Co., Ltd. 30 parts by mass of silicon dispersion (product name “BY 240-850”, manufactured by Toray Dow Corning), 0.9 parts by mass of platinum catalyst for silicone curing (product name “SRX 212”, manufactured by Toray Dow Corning) ) 2 parts by mass and a solvent were mixed to prepare a release treatment agent solution with a silicon solid content concentration of 0.7 mass%. The solvent is a mixed solvent of toluene and hexane in a volume ratio of 1:1.

Next, a biaxially stretched polyester film (product name “Lumirror Specifically, first, the above-mentioned peeling agent solution was applied to one side of the base film to form a coating film. For application, wire bar #9 was used. Next, the coating film on the base film was dried by heating at 130°C for 1 minute using a hot air dryer. In this way, a silicone release layer with a thickness of 0.10 μm was formed on the base film.

As described above, the fourth heavy release liner was produced. The fourth heavy release liner has a laminated structure of a base film and a release layer (thickness 0.10 μm).

<Production of the first light release liner>

Silicone-based release treatment agent (product name “LTC761”, a 30% by mass toluene solution of an addition-type silicone-based release treatment agent containing a polyorganosiloxane having a hexenyl group in the molecule and a polyorganosiloxane crosslinking agent having a hydrosilyl group in the molecule, Toray Dow 30 parts by mass of a silicone dispersion (product name "BY 240-850", manufactured by Toray Dow Corning), 2 parts by mass of a platinum catalyst for silicone curing (product name "SRX 212"), and a solvent. By mixing, a release treatment agent solution with a silicon solid content concentration of 0.7% by mass was prepared. The solvent is a mixed solvent of toluene and hexane in a volume ratio of 1:1.

Next, a biaxially stretched polyester film (product name “Lumirror Specifically, first, the above-mentioned peeling agent solution was applied to one side of the base film to form a coating film. For application, wire bar #9 was used. Next, the coating film on the base film was dried by heating at 130°C for 1 minute using a hot air dryer. In this way, a silicone release layer with a thickness of 0.10 μm was formed on the base film.

As described above, the first light release liner was produced. The first light release liner has a laminated structure of a base film and a release layer (thickness of 0.10 μm).

<2nd light release liner>

A film (product name "RK01ASD", manufactured by SKC Corporation) in which a release layer was formed on one side of a 50-μm-thick PET film by silicone release treatment was prepared as a second light release liner.

[Example 1]

<Preparation of adhesive composition>

First, 80 parts by mass of n-butyl acrylate (BA), 5 parts by mass of 4-hydroxybutyl acrylate (4HBA), 15 parts by mass of N-vinyl-2-pyrrolidone (NVP), and a first photopolymerization initiator ( A mixture containing 0.05 parts by mass of the product name "Irgacure 184", manufactured by BASF, and 0.05 parts by mass of the second photopolymerization initiator (product name "Irgacure 651", manufactured by BASF) was irradiated with ultraviolet rays (polymerization reaction) to produce a prepolymer composition (polymerization rate). (about 10%) was obtained (the prepolymer composition contains a monomer component that has not undergone a polymerization reaction). Next, 100 parts by mass of the prepolymer composition, 1.2 parts by mass of urethane acrylate oligomer (UAO) (product name “Art Resin UN-350”, manufactured by Negami Industries, Ltd.) as the first crosslinking agent, and a silane coupling agent (product name “KBM-403”) ", 0.3 parts by mass of 3-glycidoxypropyltrimethoxysilane, manufactured by Shin-Etsu Chemical Co., Ltd.) were mixed to obtain a first adhesive composition. The composition of the first adhesive composition is shown in Table 1. In Table 1, the units of each numerical value showing the composition of the adhesive composition are relative "parts by mass" (the same applies to Tables 2 to 4).

<Formation of adhesive layer>

First, the first adhesive composition was applied on the first heavy release liner to form a coating film. The coating film was formed on the silicone release layer of the first heavy release liner. Next, the silicone release layer side of the first light release liner was bonded to the coating film on the first heavy release liner (joining process). Next, the coating film was cured with ultraviolet rays by irradiating ultraviolet rays beyond the first easy-release liner to form a transparent first adhesive layer with a thickness of 100 μm. In ultraviolet irradiation, a black light was used as the irradiation light source, and the irradiation intensity was set to 5 mW/cm ² (the same applies to ultraviolet irradiation described later). Next, the first light release liner was peeled from the first adhesive layer on the first heavy release liner, and then the second light release liner was bonded to the exposed surface of the first adhesive layer.

As described above, the adhesive sheet with a release liner (first heavy release liner/adhesive sheet (first adhesive layer)/second light release liner) of Example 1 was produced.

[Example 2]

The adhesive sheet with a release liner of Example 2 was produced in the same manner as the adhesive sheet with a release liner of Example 1, except that the thickness of the first adhesive layer formed in the adhesive layer forming step was 130 μm.

[Example 3]

The adhesive sheet with a release liner of Example 3 was produced in the same manner as the adhesive sheet with a release liner of Example 1 except for the following. In the adhesive layer forming process, a second adhesive layer with a thickness of 250 μm was formed by using a second heavy-release liner instead of the first heavy-release liner and a second adhesive composition instead of the first adhesive composition. The second adhesive composition was prepared as follows.

First, 60 parts by mass of n-butyl acrylate (BA), 12 parts by mass of cyclohexyl acrylate (CHA), 20 parts by mass of 4-hydroxybutyl acrylate (4HBA), and 8 parts by mass of 2-hydroxyethyl acrylate (HEA). A mixture containing 0.075 parts by mass of a first photopolymerization initiator (Irgacure 184) and 0.075 parts by mass of a second photopolymerization initiator (Irgacure 651) is irradiated with ultraviolet rays (polymerization reaction) to form a prepolymer composition (polymerization rate is about 10%). ) was obtained. Next, 100 parts by mass of the prepolymer composition, 0.14 parts by mass of dipentaerythritol hexaacrylate (DPHA) as a second crosslinking agent, and 0.3 parts by mass of a silane coupling agent (KBM-403) were mixed to obtain a second adhesive composition.

[Example 4]

The adhesive sheet with a release liner of Example 4 was produced in the same manner as the adhesive sheet with a release liner of Example 3, except that the thickness of the second adhesive layer formed in the adhesive layer forming step was 500 μm.

[Example 5]

The adhesive sheet with a release liner of Example 5 was produced in the same manner as the adhesive sheet with a release liner of Example 1 except for the following. In the adhesive layer forming process, a third adhesive layer with a thickness of 50 μm was formed by using a third heavy-release liner instead of the first heavy-release liner and a third adhesive composition instead of the first adhesive composition. The third adhesive composition was prepared as follows.

First, 85 parts by mass of 2-ethylhexyl acrylate (2EHA), 5 parts by mass of 2-hydroxyethyl acrylate (HEA), 15 parts by mass of N-vinyl-2-pyrrolidone (NVP), and a first photopolymerization initiator. A mixture containing 0.05 parts by mass of (Irgacure 184) and 0.05 parts by mass of a second photopolymerization initiator (Irgacure 651) was irradiated with ultraviolet rays (polymerization reaction) to obtain a prepolymer composition (polymerization rate of about 10%). Next, 100 parts by mass of the prepolymer composition, 0.088 parts by mass of 1,6-hexanediol diacrylate (HDDA) (product name "A-HD-N", Shinnakamura Chemical Co., Ltd.) as a third crosslinking agent, and a silane couple. 0.3 parts by mass of ring agent (KBM-403) was mixed to obtain a third adhesive composition.

[Example 6]

The adhesive sheet with a release liner of Example 6 was produced in the same manner as the adhesive sheet with a release liner of Example 1 except for the following. In the adhesive layer forming process, a fourth adhesive layer with a thickness of 100 μm was formed using the fourth adhesive composition instead of the first adhesive composition. The fourth adhesive composition was prepared as follows.

First, 40.5 parts by mass of 2-ethylhexyl acrylate (2EHA), 40.5 parts by mass of isostearyl acrylate (ISTA), 1 part by mass of 4-hydroxybutyl acrylate (4HBA), and N-vinyl-2-pyrrolidone. A mixture containing 28 parts by mass of (NVP), 0.05 parts by mass of the first photopolymerization initiator (Irgacure 184), and 0.05 parts by mass of the second photopolymerization initiator (Irgacure 651) was irradiated with ultraviolet rays (polymerization reaction) to form a prepolymer composition (polymerization). The rate was about 10%). Next, 100 parts by mass of the prepolymer composition, 0.02 parts by mass of trimethylolpropane triacrylate (TMPTA) (product name "TMP3A", manufactured by Osaka Yuki Chemical Co., Ltd.) as a fourth crosslinking agent, and 0.3 parts by mass of a silane coupling agent (KBM-403). The mass parts were mixed to obtain a fourth adhesive composition.

[Example 7]

The adhesive sheet with a release liner of Example 7 was produced in the same manner as the adhesive sheet with a release liner of Example 1 except for the following. In the adhesive layer forming step, the fifth adhesive composition was used instead of the first adhesive composition to form a fifth adhesive layer with a thickness of 250 μm. The fifth adhesive composition was prepared as follows.

First, 40.5 parts by mass of 2-ethylhexyl acrylate (2EHA), 40.5 parts by mass of isostearyl acrylate (ISTA), 1 part by mass of 4-hydroxybutyl acrylate (4HBA), and N-vinyl-2-pyrrolidone. A mixture containing 28 parts by mass of (NVP), 0.05 parts by mass of the first photopolymerization initiator (Irgacure 184), and 0.05 parts by mass of the second photopolymerization initiator (Irgacure 651) was irradiated with ultraviolet rays (polymerization reaction) to form a prepolymer composition (polymerization). The rate was about 10%). Next, 100 parts by mass of the prepolymer composition, 0.15 parts by mass of TMPTA (product name "TMP3A") as a fourth crosslinking agent, 0.3 parts by mass of a silane coupling agent (KBM-403), and 0.15 parts by mass of 1-thioglycerol as a chain transfer agent were mixed. Thus, a fifth adhesive composition was obtained. The fifth adhesive composition differs from the fourth adhesive composition in the amount of the fourth crosslinking agent.

[Comparative Example 1]

The adhesive sheet with a release liner of Comparative Example 1 was produced in the same manner as the adhesive sheet with a release liner of Example 1, except that the third heavy release liner was used instead of the first heavy release liner in the adhesive layer forming process.

[Comparative Example 2]

The adhesive sheet with a release liner of Comparative Example 2 was produced in the same manner as the adhesive sheet with a release liner of Example 1 except for the following. In the adhesive layer forming process, a third heavy-release liner was used instead of the first heavy-release liner, and the thickness of the first adhesive layer formed from the first adhesive composition was 130 μm.

[Example 8]

<Preparation of adhesive composition>

First, 85 parts by mass of 2-ethylhexyl acrylate (2EHA), 5 parts by mass of 2-hydroxyethyl acrylate (HEA), 15 parts by mass of N-vinyl-2-pyrrolidone (NVP), and a first photopolymerization initiator. (product name “Irgacure 184”, 1-hydroxycyclohexyl-phenyl-ketone, manufactured by BASF) 0.05 parts by mass, and a second photopolymerization initiator (product name “Irgacure 651”, 2,2-dimethoxy-1,2-diphenyl) Containing 0.05 parts by mass of ethane-1-one, manufactured by BASF) and 0.15 parts by mass of a third photopolymerization initiator (product name “Omnirad 819”, bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide, manufactured by IGM Resins) The mixture was irradiated with ultraviolet rays (polymerization reaction) to obtain a prepolymer composition (polymerization rate of about 10%) (the prepolymer composition contains a monomer component that has not undergone a polymerization reaction). Next, 100 parts by mass of the prepolymer composition, 0.088 parts by mass of 1,6-hexanediol diacrylate (product name "A-HD-N", HDDA, Shinnakamura Chemical Co., Ltd.) as a third crosslinking agent, and a silane coupling agent. Mix 0.3 parts by mass of (product name "KBM-403", 3-glycidoxypropyltrimethoxysilane, manufactured by Shin-Etsu Chemical Co., Ltd.) with 0.9 parts by mass of an ultraviolet absorber (product name "Tinosorb S", manufactured by BASF), A sixth adhesive composition was obtained.

<Formation of adhesive layer>

First, the sixth adhesive composition was applied on the second light release liner to form a coating film. The coating film was formed on the silicone release layer of the second light release liner. Next, the silicone release layer side of the fourth heavy release liner was bonded to the coating film on the second light release liner (joining process). Next, the coating film was irradiated with ultraviolet rays through the fourth heavy release liner to cure the coating film with ultraviolet rays, thereby forming a transparent sixth adhesive layer with a thickness of 100 μm. In ultraviolet irradiation, a black light was used as the irradiation light source, and the irradiation intensity was set to 5 mW/cm ² .

As described above, the adhesive sheet with a release liner (fourth heavy release liner/adhesive sheet (sixth adhesive layer)/second light release liner) of Example 8 was produced.

[Example 9]

<Preparation of adhesive composition>

First, 80 parts by mass of n-butyl acrylate (BA), 5 parts by mass of 4-hydroxybutyl acrylate (4HBA), 15 parts by mass of N-vinyl-2-pyrrolidone (NVP), and a first photopolymerization initiator ( A mixture containing 0.05 parts by mass of Irgacure 184), 0.05 parts by mass of the second photopolymerization initiator (Irgacure 651), and 0.4 parts by mass of the third photopolymerization initiator (Omnirad 819) was irradiated with ultraviolet rays (polymerization reaction) to form a prepolymer composition (polymerization). The rate was about 10%). Next, 100 parts by mass of the prepolymer composition, 2.2 parts by mass of urethane acrylate oligomer (UAO) (product name “Art Resin UN-350”, manufactured by Negami Industries, Ltd.) as the first crosslinking agent, and 0.3 parts by mass of the silane coupling agent (KBM-403). parts by mass and 0.9 parts by mass of an ultraviolet absorber (Tinosorb S) were mixed to obtain a seventh adhesive composition.

<Formation of adhesive layer>

A 100-μm-thick adhesive layer (seventh adhesive layer) was formed between the release liners in the same manner as described above for Example 8, except that the seventh adhesive composition was used instead of the sixth adhesive composition.

As described above, the adhesive sheet with a release liner (fourth heavy release liner/adhesive sheet (seventh adhesive layer)/second light release liner) of Example 9 was produced.

[Comparative Example 3]

The pressure-sensitive adhesive sheet with a release liner of Comparative Example 1 was produced in the same manner as the pressure-sensitive adhesive sheet with a release liner of Example 8, except that no ultraviolet absorber was added in the preparation of the pressure-sensitive adhesive composition.

[Comparative Example 4]

The pressure-sensitive adhesive sheet with a release liner of Comparative Example 2 was produced in the same manner as the pressure-sensitive adhesive sheet with a release liner of Example 9, except that no ultraviolet absorber was added in the preparation of the pressure-sensitive adhesive composition.

<Haize>

For each adhesive sheet of Examples 1 to 9 and Comparative Examples 1 to 4, haze was measured as follows.

First, a sample for haze measurement was produced. Specifically, after peeling one side of the release liner from the adhesive sheet, the exposed surface of the adhesive sheet was bonded to alkali-free glass (manufactured by Matsunami Glass Co., Ltd.), and the release liner was peeled from the adhesive sheet on the glass. As a result, a sample for haze measurement was obtained. Next, about the sample, the haze was measured based on JIS K7136 (2000) using a haze meter "HM-150N" manufactured by Murakami Shikisai Kijutsu Kenkyujo Co., Ltd. In addition, in this measurement, the measurement results obtained by measuring only alkali-free glass under the same conditions were used as a baseline. The haze (%) of each adhesive sheet is shown in Tables 1 to 4.

<Shear storage modulus>

For each adhesive sheet of Examples 1 to 9 and Comparative Examples 1 to 4, dynamic viscoelasticity was measured. Specifically, it is as follows.

First, for each adhesive sheet, the required number of samples for measurement were produced. Specifically, first, a plurality of adhesive sheet pieces (for example, 20 pieces in Example 1) cut from the adhesive sheet were bonded together to produce a sample sheet with a thickness of about 2 mm. Next, this sheet was punched to obtain a cylindrical pellet (diameter 7.9 mm) as a measurement sample.

Then, the sample for measurement was fixed to a jig of a parallel plate with a diameter of 7.9 mm using a dynamic viscoelasticity measuring device (product name "Advanced Rheometric Expansion System (ARES)", manufactured by Rheometric Scientific), and then dynamic viscoelasticity measurement was performed. In this measurement, the measurement mode was set to shear mode, the measurement temperature range was -50°C to 150°C, the temperature increase rate was 5°C/min, and the frequency was 1Hz. From the measurement results, the shear storage modulus (kPa) at 25°C was read. The values are shown in Tables 1 to 4.

<Confirmation of vinyl>

The presence or absence of vinyl groups was examined on each peel surface (surface on the side where the peel layer is formed) of the fourth heavy release liner and the second light release liner mentioned above. Specifically, it is as follows.

First, the peeled surface of a sample piece (about 10 mm (first analysis). For the analysis, a time-of-flight secondary ion mass spectrometer (product name “TRIFT-V, manufactured by Albaek Pie Ltd.) was used. In addition, in this analysis, a double charge ion (Bi ₃ ⁺⁺ ) of a bismuth cluster is used as the irradiated primary ion, the primary ion acceleration voltage is set to 25 kV, and the measurement range in the sample is 300 μm × 300 μm, A neutralizing gun was used to correct charging of the sample during analysis, and the analysis mass range (m/z) was set to 0 to 1500. In both the first analysis of the fourth heavy release liner and the first analysis of the second light release liner, the mass spectrum of chlorine ions was not observed (results of the first analysis).

Meanwhile, the peeled surface of the liner piece (about 10 cm Chlorine gas in the sealed container was generated by reacting calcium hypochlorite (Ca(ClO) ₂ ) powder with hydrogen chloride (HCl). Next, the peeled surface of the sample piece (about 10 mm x about 10 mm) cut from the liner piece was subjected to component analysis by TOF-SIMS (second analysis). The method of the second analysis (equipment used and analysis conditions) is the same as the method of the first analysis described above. In the second analysis of the fourth heavy release liner, a mass spectrum of chlorine ions was observed (results of the second analysis). From the results of the first analysis and the second analysis described above, it was found that the fourth heavy release liner had a vinyl group on its release surface.

<Peel force>

For each of the adhesive sheets with a release liner in Examples 1 to 9 and Comparative Examples 1 to 4, the peeling force for peeling the heavy release liner from the adhesive sheet was measured (first measurement).

In producing the test piece for the first measurement, first, a sample sheet (100 mm in length x 25 mm in width) was cut from the adhesive sheet with a release liner. Next, the light release liner was peeled from the sample sheet, and the exposed surface of the adhesive sheet thus exposed was bonded to a glass plate to obtain a test piece.

Next, after leaving the test piece at 25°C for 60 minutes, a peeling test was conducted in which the heavy release liner in the test piece was peeled from the adhesive sheet, and the force required for peeling was measured as the peeling force. In this measurement, a tensile tester (product name “Autograph AG-50NX plus”, manufactured by Shimadzu Seisakusho) was used, the measurement temperature was 25°C, the peeling angle was 180°, and the tensile speed was 300 mm/min. (The same applies to the second measurement described later). The measured peel force (F1) (gf/25mm) is shown in Tables 1 to 4.

Meanwhile, for each of the adhesive sheets with a release liner in Examples 1 to 9 and Comparative Examples 1 to 4, the peeling force for peeling the light release liner from the adhesive sheet was measured (second measurement).

In producing the second measurement test piece, first, a sample sheet (length 100 mm x width 25 mm) was cut from the adhesive sheet with a release liner. Next, the heavy release liner side of the sample sheet was bonded to a glass plate with double-sided strong adhesive tape to obtain a test piece.

Next, after the test piece was left to stand at 25°C for 60 minutes, a peeling test was conducted in which the light release liner in the test piece was peeled from the adhesive sheet, and the force required for peeling was measured as the peeling force. The measured peel force (F2) (gf/25mm) is shown in Tables 1 to 4. The difference (F1-F2) (gf/25mm) between the peel force (F1) and the peel force (F2), and the ratio (F1/F2) of the peel force (F1) to the peel force (F2), Tables 1 to 1 It is shown in 4.

<Shear tensile test>

A shear tensile test was performed on each of the adhesive sheets with release liners in Examples 1 to 9 and Comparative Examples 1 to 4. Specifically, it is as follows.

In producing the test piece, first, a sample sheet (length 200 mm x width 20 mm) was cut from the adhesive sheet with a release liner. Fig. 4A is a schematic cross-sectional view of the sample sheet Sa in the longitudinal direction. Next, the release liner 20 is separated from the release liner 30 (light release liner) at a location 90 mm from one end (right end in the drawing) in the longitudinal direction of the sample sheet Sa. ) (heavy release liner) was cut with a cutter knife (the cut point is indicated by a broken line). Next, as shown in FIG. 4B, the one end side of the release liner 30 and the adhesive sheet 10 was removed from the cut location. Next, as shown in FIG. 4C, a point 90 mm from the other end (left end in the figure) in the longitudinal direction of the sample sheet Sa is from the release liner 20 side in the thickness direction H. It was cut with a cutter knife until it reached the release liner 30 (the cut point is indicated by a broken line). Next, as shown in FIG. 4D, the other end side of the release liner 20 and the adhesive sheet 10 was removed from the cut location. Next, after peeling the release liner 30 from the adhesive sheet 10, as shown in FIG. 4E, the surface of the adhesive sheet 10 exposed by the peeling was coated with a methacrylic substrate 40 (product name “ It was press-bonded with "Acrylite L", manufactured by Mitsubishi Chemical Corporation. As a result, a test piece (Z) was obtained.

Then, the release liner 20 in the test piece Z was tested in the plane direction D with respect to the methacrylic substrate 40 using a tensile tester (product name “Autograph AG-50NX plus”, manufactured by Shimadzu Seisakusho). A tensile shear tensile test was performed (in FIG. 4E, the tensile direction is indicated by an arrow from the release liner 20). In this test, the measurement temperature was 25°C, the initial distance between chucks was 100 mm, and the tensile speed was 10 mm/min. An example of a graph (stress curve) obtained by such a shear tensile test is shown in Fig. 5 (the graph in Fig. 5 is the measurement result for the adhesive sheet with a release liner of Example 2). In the graph of Figure 5, the horizontal axis represents the growth amount (mm) in the plane direction of the heavy release liner stretched in the plane direction as a stroke (mm), and the vertical axis represents the stress (N) of the heavy release liner. The growth amount of the heavy release liner corresponds to the moving distance (stroke length) of the jig (chuck) that pulls the heavy release liner in the shear direction. In this shear tensile test, the stress is measured on a 20 mm x 20 mm size adhesive sheet piece of the adhesive sheet 10. Additionally, in Figure 5, a dot (P) and a broken line (B) are also shown. Point P is a point showing the maximum stress (X) in the stress curve. The slope of the broken line (B) corresponds to the average rate of change (Y) (N/mm) from the stress of 5N to the stress of 10N in the shear tensile test. The slope of the dashed line (B) is calculated by (10-5)/(r2-r1) from the growth amount ((r1) at a stress of 5N and the growth amount (r2) at a stress of 10N in the shear tensile test. The maximum stress (X) (N) and average rate of change (Y) (N/mm) in the shear tensile test are shown in Tables 1 to 4.

In addition, for each of the adhesive sheets with release liners of Examples 1 to 9 and Comparative Examples 1 to 4, the measurement results of the maximum stress ( It appears in In the graph of FIG. 6, the horizontal axis represents the maximum stress (X) (N), and the vertical axis represents the average rate of change (Y) (N/mm). In Figure 6, plots (E1 to E9) show measurement results in Examples 1 to 9. Plots (C1 to C4) show the measurement results in Comparative Examples 1 to 4. The dotted line (L1) represents the line of maximum stress (X) = 24 (N). The dotted line (L2) represents the line of average rate of change (Y) (N/mm) = -1.43 × maximum stress (X) (N) + 70. The pressure-sensitive adhesive sheets with release liners of Examples 1 to 9 had a maximum stress (X) (N) of 24 N or more at 25°C. For the adhesive sheets with release liners of Examples 1 to 9, at 25°C, the maximum stress (X) (N) and average rate of change (Y) (N/mm) satisfy the relationship of Y≥-1.43X+70. do. The pressure-sensitive adhesive sheets with release liners of Examples 1 to 9 showed good results in the first and second evaluation tests described later.

<Suppression of peeling of medium peeling liner when peeling of light peeling liner>

For each of the adhesive sheets with a release liner in Examples 1 to 9 and Comparative Examples 1 to 4, the difficulty of peeling the heavy release liner when peeling the light release liner was investigated (first evaluation test). Specifically, first, 10 evaluation samples were produced for each adhesive sheet with release liner. Next, the light release liner of each evaluation sample was peeled. For peeling, a tensile tester (product name “Autograph AG-50NX plus”, manufactured by Shimadzu Seisakusho) was used. In peeling, the measurement temperature was 25°C, the peeling angle was 180°, and the tensile speed was 300 mm/min. In addition, when the number of evaluation samples that could properly peel only the light release liner without causing peeling of the heavy release liner was 10, it was evaluated as “excellent,” when it was 7 to 9, it was evaluated as “good,” and 0. The case of 6 to 6 was evaluated as “poor”. The evaluation results are shown in Tables 1 to 4.

On the other hand, for each of the adhesive sheets with a release liner in Examples 1 to 9 and Comparative Examples 1 to 4, the peeling difficulty of the heavy release liner when the light release liner was peeled was conducted in the same manner as the first evaluation test except for the following. was investigated (second evaluation test). Before producing the evaluation sample, the adhesive sheet with a release liner was stored for 14 days at 65°C and 90% relative humidity. The evaluation results of this second evaluation test are shown in Tables 1 to 4.

S: Adhesive sheet with release liner
S': Laminated film
H: Thickness direction
10: Adhesive sheet
11: side 1
12: Side 2
20: Release liner (medium release liner)
20a: extended protruding end
21: peeling surface
30: Release liner (light release liner)
30a: extended protruding end
31: peeling surface

Claims (8)

an adhesive sheet having a first side and a second side opposite to the first side;
A mid-release liner in peelable contact with the first surface,
A light release liner is provided in peelable contact with the second surface,
An adhesive sheet with a release liner, wherein the maximum stress ( According to paragraph 1,
An adhesive sheet with a release liner, wherein the average rate of change (Y) (N/mm) from the stress of 5N to the stress of 10N in the shear tensile test satisfies Y≥-1.43X+70. According to paragraph 1,
An adhesive sheet with a release liner, wherein the maximum length of the heavy release liner is 20 mm or more. According to paragraph 1,
The difference (F1-F2) between the peeling force (F1) for peeling the heavy release liner from the adhesive sheet and the peeling force (F2) for peeling the light release liner from the adhesive sheet is 10 gf/25mm or more. , adhesive sheet with release liner. According to paragraph 1,
The difference (F1-F2) between the peeling force (F1) for peeling the heavy release liner from the adhesive sheet and the peeling force (F2) for peeling the light release liner from the adhesive sheet is 500 gf/25mm or less. , adhesive sheet with release liner. According to paragraph 1,
An adhesive sheet with a release liner, wherein the adhesive sheet is an inorganic adhesive sheet. According to any one of claims 1 to 6,
An adhesive sheet with a release liner, wherein the adhesive sheet is a photocured product of a photopolymerizable adhesive composition containing an ultraviolet absorber. A laminated film comprising a heavy release liner, a composition layer of a photopolymerizable adhesive composition containing an ultraviolet absorber, and a light release liner in this order in the thickness direction, wherein the heavy release liner has a vinyl group on the surface of the composition layer side. A preparation process for preparing a laminated film,
A method of producing an adhesive sheet with a release liner, comprising an adhesive sheet forming step of photocuring the composition layer to form an adhesive sheet by irradiating ultraviolet rays to the laminated film from the heavy release liner side.