JP2022058224A - Optical adhesive sheet having separator - Google Patents

Abstract

To provide an optical adhesive sheet having a separator appropriate for achieving a lower power consumption at a display panel.SOLUTION: An adhesive sheet X is an optical adhesive sheet having a separator including an adhesive layer 20 and a separator 10 arranged on one side in a thickness direction of the adhesive layer 20. In the adhesive sheet X, a ratio of a sum total of projection areas of foreign substances of maximum length 15 to 30 μm is 20% or less at a projection plane of a plane view projection by a prescribed evaluation method, and the number of foreign substances of maximum length 30 μm or longer is 1 or less.SELECTED DRAWING: Figure 1

Description

The present invention relates to an optical adhesive sheet with a separator.

The light-transmitting pressure-sensitive adhesive sheet (optical pressure-sensitive adhesive sheet) is used in the manufacture of display panels such as organic EL panels. The display panel has a laminated structure including a pixel panel, a cover member, and the like. In the process of manufacturing a display panel, the optical adhesive sheet is used for joining elements included in the laminated structure on the light emitting side (image display side) of the pixel panel. As described above, the optical adhesive sheet is an adhesive sheet arranged at a place where light passes in the display panel. Further, the optical pressure-sensitive adhesive sheet is manufactured, for example, in the form of an optical pressure-sensitive adhesive sheet with a separator in which one side or both sides of the sheet is coated with a separator (peeling liner). A technique relating to such an optical adhesive sheet is described in, for example, Patent Document 1 below.

Japanese Unexamined Patent Publication No. 2007-2700064

Display panels are required to be thinner and lighter, while higher functionality such as higher definition display images is advancing. In order to achieve high functionality, thinness, and weight reduction in display panels, it is important to reduce the power consumption of the panels. In particular, it is very important to reduce power consumption in display panels for wearable devices such as smart watches.

The present invention provides an optical adhesive sheet with a separator suitable for reducing the power consumption of a display panel.

The present invention [1] is an optical pressure-sensitive adhesive sheet with a separator comprising a pressure-sensitive adhesive layer and a separator arranged on one side in the thickness direction of the pressure-sensitive adhesive layer, and is a projection of a plan view projection by the following evaluation method. Includes an optical adhesive sheet with a separator, wherein the ratio of the total projected area of foreign matter having a maximum length of 15 μm or more and 30 μm or less on a surface is 20% or less, and the number of foreign matter having a maximum length of 30 μm or more is 1 or less. ..

Evaluation method: The following first to third steps are carried out using a device including the following light source and camera device.

Light source: White LED light source for irradiating the sample for evaluation with inspection light Camera device: The sample transmitted light and sample reflected light of the inspection light are arranged so as to be able to be imaged, and have a resolution of 2.8 μm. , Camera device

First step: The optical adhesive sheet with a separator having a plan view size of 50 mm × 50 mm is prepared as a sample for evaluation, and the inner region (30 mm × 30 mm) surrounded by the outer region in the sample is imaged by the camera device. The sample is set in the apparatus in a state where it can be used.
Second step: While irradiating the sample with inspection light from the white LED light source, the camera device is used to receive the sample transmitted light and / or the sample reflected light, and the received light data is transmitted over the inner region. get.
Third step: Using the received light data, the position information and the projected image information of the foreign matter on the projection surface of the plan view projection of the inner region are derived.

The present invention [2] includes the optical pressure-sensitive adhesive sheet with a separator according to the above [1], further comprising a separator arranged on the other side in the thickness direction of the pressure-sensitive adhesive layer.

The present invention [3] includes the optical pressure-sensitive adhesive sheet with a separator according to the above [1] or [2], wherein the maximum number of foreign substances is 10 or less.

The present invention [4] is the optical pressure-sensitive adhesive sheet with a separator according to any one of the above [1] to [3], wherein the maximum length of the maximum foreign matter in the plan view projection is 15 μm or more and 30 μm or less. include.

The present invention [5] is any one of the above [1] to [4], wherein the ratio of the total projected area of bubbles having a maximum length of 15 μm or more and 30 μm or less on the projection surface of the plan view projection is 10% or less. Includes the optical adhesive sheet with separator described in one.

The present invention [6] includes the optical pressure-sensitive adhesive sheet with a separator according to the above [5], wherein the maximum number of bubbles is 0.

The present invention [7] is the optical pressure-sensitive adhesive sheet with a separator according to any one of the above [1] to [6], wherein the maximum length of the maximum bubble in the plan view projection is 15 μm or more and 30 μm or less. include.

The present invention [8] is described in any one of the above [1] to [7], wherein the separator has a ratio of the total projected area of foreign substances on the projection surface of the plan view projection of 20% or less. Includes optical adhesive sheet with separator.

The present invention [9] includes the optical pressure-sensitive adhesive sheet with a separator according to any one of the above [1] to [8], wherein the separator has a surface having a surface roughness Ra of 20 nm or less.

In the optical adhesive sheet with a separator of the present invention, the ratio of the total projected area of foreign substances having a maximum length of 15 μm or more and 30 μm or less on the projection surface of the plan view projection by the above evaluation method is 20% or less, and the maximum length is 30 μm. The number of the above foreign substances is 1 or less. In addition, in the optical pressure-sensitive adhesive sheet with a separator, environmental foreign matter is suppressed from adhering to the pressure-sensitive adhesive layer until the separator is peeled off from the pressure-sensitive adhesive layer. Such an optical pressure-sensitive adhesive sheet with a separator is suitable for supplying a highly clean pressure-sensitive adhesive layer as an optical pressure-sensitive adhesive sheet in the process of manufacturing a display panel, and therefore, a display panel having a high degree of cleanliness at a light passing portion is manufactured. Suitable for. In the display panel, the higher the cleanliness of the light passing portion, the higher the brightness of the image displayed by the panel. Increasing the brightness in such an aspect is useful for reducing the power consumption of the display panel. Therefore, the optical adhesive sheet with a separator is suitable for reducing the power consumption of the display panel.

It is sectional drawing of one Embodiment of the optical adhesive sheet with a separator of this invention. It is sectional drawing of the modification of the optical adhesive sheet with a separator of this invention. In this modification, the separator is arranged on one side of the optical adhesive sheet.

As shown in FIG. 1, the optical pressure-sensitive adhesive sheet X with a separator as an embodiment of the optical pressure-sensitive adhesive sheet with a separator of the present invention includes a first separator 10 (separator 10A), an optical pressure-sensitive adhesive sheet 20, and a second separator. 10 (separator 10B) is provided in this order in the thickness direction D. The optical adhesive sheet X with a separator has a sheet shape and extends in a direction (plane direction) orthogonal to the thickness direction D.

The separator 10 is a protective film for an optical adhesive sheet. In the present embodiment, the separator 10A is arranged on one surface of the optical adhesive sheet 20 in the thickness direction D, and the separator 10B is arranged on the other surface of the optical adhesive sheet 20 in the thickness direction D. As shown in FIG. 2, the optical pressure-sensitive adhesive sheet X with a separator does not have to include one of the separators 10. The optical pressure-sensitive adhesive sheet X with a separator takes, for example, a roll (not shown) in a state where both sides or one side is covered with the separator 10.

The optical pressure-sensitive adhesive sheet 20 is a pressure-sensitive adhesive sheet having a transparent pressure-sensitive adhesive layer 21 arranged at a light passing portion of the display panel, and is used as a component of the display panel. The display panel has a laminated structure including a pixel panel, a cover member, and the like. In the process of manufacturing a display panel, predetermined elements arranged on the image display side of the pixel panel are bonded to each other by an optical adhesive sheet. Such display panels include panels for ultra-high definition displays for VR (Virtual Reality) applications or AR (Augmented Reality) applications.

The optical adhesive sheet X with a separator has a total ratio (foreign matter area ratio R1) of foreign matter having a maximum length of 15 μm or more and 30 μm or less on the projection surface of a plan view projected by the following evaluation method of 20% or less. Moreover, the number of foreign substances having a maximum length of 30 μm or more is 1 or less. Foreign substances include environmental foreign substances, foreign substances as impurities of raw materials, foreign substances caused by material modification, and air bubbles. Examples of environmental foreign substances include fiber pieces, skin pieces, metal fine particles, fine oil droplets, and salt fine particles derived from sweat. These foreign substances are sometimes referred to as defects in separators and optical adhesive sheets.

Evaluation method: The following first to third steps are carried out using an evaluation device including the following light source and camera device.

Light source: White LED light source for irradiating the sample for evaluation with inspection light Camera device: The sample transmitted light and sample reflected light of the inspection light are arranged so as to be able to be imaged, and have a resolution of 2.8 μm. , Camera device

First step: A separator 10 having a plan view size of 50 mm × 50 mm is prepared as a sample for evaluation, and an inner region (30 mm × 30 mm) surrounded by an outer region in the sample can be imaged by the camera device. The sample is set in the evaluation device.
Second step: While irradiating the sample with inspection light from the white LED light source, the camera device is used to receive the sample transmitted light and / or the sample reflected light, and the received light data is transmitted over the inner region. get. The sample transmitted light is light that transmits the sample in the thickness direction. The sample reflected light is the light reflected by the sample.
Third step: Using the received light data, the position information and the projected image information of the foreign matter (each of the foreign matter existing in the inner region) on the projection surface of the plan view projection of the inner region are derived.

The above evaluation method may be carried out in the manufacturing process of the optical adhesive sheet 20. For example, the above evaluation method may be carried out as a precise foreign matter inspection (defect inspection) for checking the presence or absence of minute foreign matter on the optical adhesive sheet 20.

In the foreign matter inspection carried out in the manufacturing process of the optical adhesive sheet 20, with both sides of the optical adhesive sheet 20 protected by the separator 10, the optical adhesive sheet 20 is exposed to the optical adhesive sheet 20 from one side of the sheet through the separator 10. It is irradiated with inspection light. Visible light is used as the inspection light. The wavelength of visible light as inspection light is included in the range of, for example, 400 to 800 nm. As the light source of this visible light, for example, a white LED light source is used. Infrared rays may be used as the inspection light. The wavelength of infrared rays as inspection light is included in the range of, for example, 800 to 1200 nm. As the light source of this infrared ray, for example, an infrared lamp is used.

In the optical pressure-sensitive adhesive sheet X with a separator, the foreign matter area ratio R1 is 20% or less, and the number of foreign matters having a maximum length of 30 μm or more is 1 or less. In addition, in the optical pressure-sensitive adhesive sheet X with a separator, environmental foreign matter is suppressed from adhering to the optical pressure-sensitive adhesive sheet 20 until the separator 10 is peeled off from the optical pressure-sensitive adhesive sheet 20. Such an optical adhesive sheet X with a separator is suitable for supplying an adhesive layer having a high degree of cleanliness as an optical adhesive sheet in the process of manufacturing a display panel, and therefore, a display panel having a high degree of cleanliness at a light passing portion is manufactured. Suitable for In the display panel, the higher the cleanliness of the light passing portion, the higher the brightness of the image displayed by the panel. Increasing the brightness in such an aspect is useful for reducing the power consumption of the display panel. Therefore, the optical adhesive sheet X with a separator is suitable for reducing the power consumption of the display panel. When the optical pressure-sensitive adhesive sheet X with a separator is used in the manufacturing process of an ultra-high pixel display panel, the optical pressure-sensitive adhesive sheet X with a separator can be used as a supply material for the optical pressure-sensitive adhesive sheet 20 having a high degree of cleanliness. Helps improve the quality of displayed images.

In the above evaluation device, the resolution of the camera device is 2.8 μm as described above, but may be, for example, 10 μm or less, preferably 5 μm or less. Further, the camera device may include a lens (that is, the light receiving element included in the camera device may have a configuration in which light is received through the lens). Further, in the above evaluation device, the white LED light source and the LED light source of another color can be combined to carry out the evaluation method including the first to third steps and other evaluation methods (LED light source of another color). Examples include a red LED light source and a blue LED light source). For example, by using an LED light source of another color alone as a light source or by using an LED light source of two or more colors in combination as a light source, it becomes easy to carry out the above-mentioned foreign matter inspection depending on the inspection target.

In the first step of the above evaluation method, the sample is set in the evaluation device by, for example, having the chuck mechanism provided in the evaluation device grip the outer region of the sample. In the second step, for example, the light receiving surface of the camera device to be used is arranged to face the inner region of the sample, and the camera device performs scanning along the inner region. The position information derived in the third step includes, for example, XY coordinate information having the projection plane as the XY plane and Z coordinate information having the thickness direction orthogonal to the XY plane as the Z direction. Is included. The projection image information derived in the third step is information that can derive at least the total area of the foreign matter based on the information, and is, for example, information that can further derive the size of each foreign matter and the size distribution of the foreign matter.

The foreign matter area ratio R1 is preferably 18% or less, more preferably 15% or less, still more preferably 12% or less, and particularly preferably 10% or less. From the viewpoint of supplying the optical adhesive sheet 20 having a high degree of cleanliness in the process of manufacturing the display panel, the foreign matter area ratio R1 is preferably close to 0%.

In the optical adhesive sheet X with a separator, the ratio of the total projected area of foreign matter (all foreign matter to be measured) on the projection surface of the plan view projection (foreign matter area ratio R2) is 20% or less.

The foreign matter area ratio R2 is preferably 18% or less, more preferably 15% or less, still more preferably 12% or less, and particularly preferably 10% or less. From the viewpoint of supplying the optical adhesive sheet 20 having a high degree of cleanliness in the manufacturing process of the display panel, the foreign matter area ratio R2

The number of foreign substances having a maximum length of 15 μm or more and 30 μm or less in the plan view projection of the optical adhesive sheet X with a separator is preferably 10 or less, more preferably 7 or less, still more preferably 4 or less, and particularly preferably 3 or less. , More preferably 2 or less, particularly preferably 1 or less, and extremely preferably 0. Such a configuration is suitable for supplying the optical adhesive sheet 20 having a high degree of cleanliness in the process of manufacturing the display panel, and is therefore suitable for reducing the power consumption of the display panel.

The optical pressure-sensitive adhesive sheet X with a separator has a maximum length (maximum foreign matter length L1) possessed by the maximum foreign matter in the plan view projection, preferably 30 μm or less, more preferably 20 μm or less, still more preferably 18 μm or less. Such a configuration is suitable for supplying the optical adhesive sheet 20 having a high degree of cleanliness in the process of manufacturing the display panel, and is therefore suitable for reducing the power consumption of the display panel. The maximum foreign matter length L1 is, for example, 15 μm or more. Even if the maximum foreign matter length L1 is 15 μm or more, depending on the display panel to be manufactured, the cleanliness level required for the light passing portion may be satisfied.

The optical pressure-sensitive adhesive sheet X with a separator preferably has the maximum length (maximum foreign matter length L2) of the maximum foreign matter between the separator 10 and the optical pressure-sensitive adhesive sheet 20 (adhesive layer 21) in the plan view projection. Is 30 μm or less, more preferably 20 μm or less, still more preferably 18 μm or less. Such a configuration is suitable for supplying the optical adhesive sheet 20 having a high degree of cleanliness in the process of manufacturing the display panel, and is therefore suitable for reducing the power consumption of the display panel. The maximum foreign matter length L2 is, for example, 15 μm or more. Even if the maximum length L2 of foreign matter is 15 μm or more, the cleanliness level required for the light passing portion may be satisfied depending on the display panel to be manufactured.

In the optical adhesive sheet X with a separator, the ratio of the total projected area of bubbles having a maximum length of 15 μm or more and 30 μm or less (bubble area ratio R3) on the projection surface of the plan view projection is preferably 10% or less, more preferably. It is 8% or less, more preferably 6% or less, particularly preferably 4% or less, even more preferably 2% or less, particularly preferably 1% or less, and extremely preferably 0%. Such a configuration is suitable for supplying the optical adhesive sheet 20 having a high degree of cleanliness in the process of manufacturing the display panel, and is therefore suitable for reducing the power consumption of the display panel. Examples of the bubbles in the optical pressure-sensitive adhesive sheet X with a separator include bubbles existing at the interface between the separator 10 and the pressure-sensitive adhesive layer 21 and bubbles existing inside the pressure-sensitive adhesive layer 21.

In the optical adhesive sheet X with a separator, the ratio of the total projected area of bubbles on the projection surface of the plan view projection (bubble area ratio R4) is preferably 10% or less, more preferably 8% or less, still more preferably 6%. Hereinafter, it is particularly preferably 4% or less, further preferably 2% or less, particularly preferably 1% or less, and extremely preferably 0%. Such a configuration is suitable for supplying the optical adhesive sheet 20 having a high degree of cleanliness in the process of manufacturing the display panel, and is therefore suitable for reducing the power consumption of the display panel.

In the optical pressure-sensitive adhesive sheet X with a separator, the number of bubbles having a maximum length of 15 μm or more and 30 μm or less in the plan view projection is preferably 0. The optical pressure-sensitive adhesive sheet X with a separator has a maximum length of preferably 15 μm or more and 30 μm or less, which is possessed by the maximum bubble in the plan view projection. These configurations are suitable for supplying the optical adhesive sheet 20 having a high degree of cleanliness in the process of manufacturing the display panel, and therefore suitable for reducing the power consumption of the display panel.

As a method of controlling foreign matter inside and on the surface of the optical adhesive sheet X with a separator (controlling the presence or absence of foreign matter and its size), for example, foreign matter control on the inside and surface of the separator 10 and foreign matter control on the inside and surface of the optical adhesive sheet 20. , And suppression of bubble formation at the interface between the separator 10 and the optical pressure-sensitive adhesive sheet 20. As a method for controlling foreign matter inside and on the surface of the separator 10, for example, selection of the type of resin material forming the separator, filler-less resin material, adjustment of the filtering diameter of the resin material used for film formation, and Control of air cleanliness in the separator production line (control of exhaust removal of suspended fine particles, etc.) can be mentioned. Methods for controlling foreign matter inside and on the surface of the optical adhesive sheet 20 include, for example, manufacturing in a clean room, prevention of foreign matter from adhering to the surface with a protective film, purification of raw materials, adjustment of raw material composition, and filtering of raw materials. ..

In the separator 10, the ratio of the total projected area of foreign matter on the projection surface of the plan view projection (foreign matter area ratio R5) is preferably 20% or less, more preferably 18% or less, still more preferably 15% or less, and particularly further. It is preferably 12% or less, and particularly preferably 10% or less. From the viewpoint of supplying the optical adhesive sheet 20 having a high degree of cleanliness in the process of manufacturing the display panel, the foreign matter area ratio R5 is preferably close to 0%.

The separator 10 has a maximum length (maximum foreign matter length L3) of the maximum foreign matter in the plan view projection, preferably 30 μm or less, more preferably 20 μm or less, still more preferably 15 μm or less, and particularly preferably 8 μm or less. .. Such a configuration is suitable for inspecting the optical adhesive sheet for the presence or absence of foreign matter having a maximum length of slightly more than 30 μm in plan view projection (for example, foreign matter having a maximum length of about 33 μm). From the viewpoint of carrying out the above-mentioned precise foreign matter inspection, the shorter the maximum foreign matter length L3 is, the more preferable.

The separator 10 has a number of foreign substances having a maximum length of 20 μm or more and 30 μm or less (number of foreign substances in the first range N1) in the plan view projection, preferably 5 or less, more preferably 4 or less, still more preferably 3 or less. It is particularly preferably 2 or less, particularly preferably 1 or less, and extremely preferably 0. Such a configuration is suitable for performing a precise foreign matter inspection on the optical pressure-sensitive adhesive sheet 20, and is therefore suitable for supplying the optical pressure-sensitive adhesive sheet 20 having a high degree of cleanliness in the manufacturing process of the display panel.

In the separator 10, the number of foreign substances having a maximum length of 15 μm or more and 30 μm or less in the plan view projection (the number of foreign substances in the second range N2) is preferably 10 or less, more preferably 7 or less, still more preferably 4 or less. It is particularly preferably 3 or less, further preferably 2 or less, particularly preferably 1 or less, and extremely preferably 0. Such a configuration is suitable for performing a precise foreign matter inspection on the optical pressure-sensitive adhesive sheet 20, and is therefore suitable for supplying the optical pressure-sensitive adhesive sheet 20 having a high degree of cleanliness in the manufacturing process of the display panel.

The separator 10 (separator 10A, separator 10B) includes the base film 11 and the release layer 12 in the present embodiment. The release layer 12 is arranged on one side of the base film 11.

The base film 11 is, for example, a flexible and transparent resin film. Examples of the resin material of the base film 11 include polyolefin, polyester, acrylic, polyamide, polyimide, polyvinyl chloride, polyvinylidene chloride, cellulose, modified cellulose, polystyrene, and polycarbonate. Examples of the polyolefin include polyethylene, polypropylene, cycloolefin polymer (COP), poly-1-butene, poly-4-methyl-1-pentene, ethylene / propylene copolymer, ethylene / 1-butene copolymer, and ethylene. -Examples include vinyl acetate copolymers, ethylene / ethyl acrylate copolymers, and ethylene / vinyl alcohol copolymers. Examples of the polyester include polyethylene terephthalate, polyethylene naphthalate, and polybutylene terephthalate. Examples of the polyamide include polyamide 6, polyamide 6, 6 and partially aromatic polyamide. Examples of the modified cellulose include triacetyl cellulose (TAC). These resin materials may be used alone or in combination of two or more. As the material of the base film 11, a material having a high degree of cleanliness used in optical applications is preferable. From the viewpoint of obtaining the separator 10 having a high degree of cleanliness, polyolefin is preferably used as the material of the base film 11, and COP is more preferably used.

Further, the resin material preferably contains no filler or substantially no filler. On the other hand, when the resin material contains a filler, the filler is preferably a nanofiller (the nanofiller means particles having a maximum length of 100 nm or less). These configurations are preferable from the viewpoint of obtaining a separator 10 having a high degree of cleanliness.

The thickness of the base film 11 is preferably 5 μm or more, more preferably 10 μm or more, and more preferably 20 μm or more from the viewpoint of ensuring the strength of the separator 10. Further, from the viewpoint of ensuring appropriate flexibility in the separator 10, the thickness of the base film 11 is preferably 200 μm or less, more preferably 150 μm or less, still more preferably 100 μm or less.

The release layer 12 is a layer for ensuring the peelability of the optical adhesive sheet from the surface of the separator. Examples of the material of the release layer 12 include a silicone resin, a long-chain alkyl resin, and a fatty acid amide resin. These resins may contain fluorine atoms in the polymer side chains. For example, the silicone resin may be a fluorinated silicone resin containing a fluorine atom in the side chain.

The separator 10 can be manufactured, for example, as follows. First, the molten resin material is molded into a film to produce a base film 11. Molding methods include, for example, extrusion molding, inflation molding, and calendar molding. Next, one side of the base film 11 is treated with a release agent to form a release layer 12 (a film of a release agent). The release agent contains, for example, any one of the above-mentioned resins as the material of the release layer 12. The separator 10 is preferably manufactured in a clean room. The higher the air cleanliness in the production line of the separator 10 (for example, the air cleanliness in the clean room), the smaller the amount of environmental foreign matter inside and the surface of the separator 10 to be manufactured, and the smaller the size of the environmental foreign matter. The air cleanliness of the production line is preferably class 3 or less, more preferably class 2 or less, still more preferably class 1 in the ISO 14644-1 standard.

The separator 10 has transparency in this embodiment. The haze of the separator 10 is preferably 3% or less, more preferably 2% or less, still more preferably 1% or less. The haze of the separator 10 can be measured using a haze meter in accordance with JIS K7136 (2000).

The transmittance of the light emitted from the white LED light source in the separator 10 is, for example, 50% or more, preferably 80% or more, and more preferably 90% or more. Such a configuration is preferable from the viewpoint of appropriately performing a foreign matter inspection using a white LED light source. The infrared transmittance of the separator 10 is, for example, 50% or more, preferably 80% or more, and more preferably 90% or more. Such a configuration is preferable from the viewpoint of appropriately performing a foreign matter inspection using infrared rays.

The separator 10 preferably has a surface having a surface roughness Ra of 20 nm or less. When the separator 10 has the release layer 12, the surface roughness Ra of the exposed surface of the release layer 12 is preferably 20 nm or less. The surface roughness Ra is more preferably 17 nm or less, further preferably 15 nm or less, particularly preferably 12 nm or less, still more preferably 10 nm or less, still more preferably 8 nm or less, particularly preferably 6 nm or less, and extremely preferably 5 nm or less. Is. Such a configuration regarding surface roughness is preferable from the viewpoint of suppressing foreign matter from entering the surface of the separator, and is useful for manufacturing an optical adhesive sheet that requires a high degree of cleanliness by using the separator 10. The surface roughness Ra is, for example, 0.1 nm or more. The surface roughness Ra is the arithmetic mean roughness of the surface and can be measured by the method described later with respect to the examples.

The separator 10 preferably has a surface having a surface roughness Rz of 600 nm or less. When the separator 10 has the release layer 12, the surface roughness Rz of the exposed surface of the release layer 12 is preferably 600 nm or less. The surface roughness Rz is more preferably 400 nm or less, further preferably 300 nm or less, particularly preferably 200 nm or less, still more preferably 100 nm or less, still more preferably 80 nm or less, particularly preferably 60 nm or less, and extremely preferably 50 nm or less. Is. Such a configuration regarding surface roughness is preferable from the viewpoint of suppressing foreign matter from adhering to the surface of the separator, and is useful for manufacturing an optical pressure-sensitive adhesive sheet that requires a high degree of cleanliness by using the separator 10. The surface roughness Rz is, for example, 1 nm or more. The surface roughness Rz is a ten-point average roughness of the surface, and can be measured by the method described later with respect to Examples.

The peeling adhesive force (first peeling adhesive force) between the release layer 12 (release layer 12A) of the separator 10A and the pressure-sensitive adhesive layer 21, and the release layer 12 (release layer 12B) and the pressure-sensitive adhesive of the separator 10B. It is preferable that it is different from the peeling adhesive force (second peeling adhesive force) between the layer 21 and the layer 21. For example, when the first peeling adhesive force is larger than the second peeling adhesive force, when the optical adhesive sheet X with a separator is used in the manufacturing process of the display panel, the separator 10B is first peeled off from the optical adhesive sheet X with a separator. Ru. Next, the surface of the pressure-sensitive adhesive layer 21 exposed by the peeling is attached to the adherend. After that, the separator 10A is peeled off from the optical pressure-sensitive adhesive sheet X with a separator on the adherend. The peeling adhesive force between the release layer 12 and the pressure-sensitive adhesive layer 21 can be adjusted, for example, by selecting the type of material of the release layer 12 and adjusting the concentration of the material.

The optical pressure-sensitive adhesive sheet 20 is an optical pressure-sensitive adhesive sheet having a transparent pressure-sensitive adhesive layer 21. The pressure-sensitive adhesive layer 21 is a pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition and has transparency (visible light transmission). The tacky composition contains a base polymer.

The base polymer is a pressure-sensitive component for developing adhesiveness in the pressure-sensitive adhesive layer 21. The base polymer exhibits rubber elasticity at room temperature. Examples of the base polymer include acrylic polymers, rubber polymers, polyester polymers, urethane polymers, polyether polymers, silicone polymers, polyamide polymers, and fluoropolymers. From the viewpoint of ensuring good transparency and tackiness in the pressure-sensitive adhesive layer 21, an acrylic base polymer is preferably used as the base polymer.

Acrylic-based polymers contain (meth) acrylic acid alkyl esters as the main constituent monomer components. By "(meth) acrylic" is meant acrylic and / or methacrylic.

As the (meth) acrylic acid alkyl ester, a (meth) acrylic acid alkyl ester having an alkyl group having 1 to 20 carbon atoms, that is, a (meth) acrylic acid C _1-20 alkyl ester is preferably 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 the (meth) acrylic acid alkyl ester having a linear or branched alkyl group include methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, and isobutyl (meth) acrylate. , (Meta) s-butyl acrylate, (meth) t-butyl acrylate, (meth) pentyl acrylate, (meth) isopentyl acrylate, (meth) neo-pentyl acrylate, (meth) hexyl acrylate, (meth) Heptyl acrylate, 2-ethylhexyl (meth) acrylate, octyl (meth) acrylate, isooctyl (meth) acrylate, nonyl (meth) acrylate, isononyl (meth) acrylate, decyl (meth) acrylate, (meth) ) Isodecyl acrylate, (meth) undecyl acrylate, (meth) dodecyl acrylate, (meth) isotridecyl acrylate, (meth) tetradecyl acrylate, (meth) isotetradecyl acrylate, (meth) pentadecyl acrylate, (meth) Examples include cetyl acrylate, heptadecyl (meth) acrylate, octadecyl (meth) acrylate, isooctadecyl (meth) acrylate, and nonadecil (meth) acrylate.

Examples of the (meth) acrylic acid alkyl ester having an alicyclic alkyl group include a (meth) acrylic acid cycloalkyl ester, a (meth) acrylic acid ester having a bicyclic aliphatic hydrocarbon ring, and a tricycle. Examples thereof include (meth) acrylic acid esters having the above aliphatic hydrocarbon rings. Examples of the (meth) acrylic acid cycloalkyl ester include (meth) acrylic acid cyclopentyl, (meth) acrylic acid cyclohexyl, (meth) acrylic acid cycloheptyl, and (meth) acrylic acid cyclooctyl. Examples of the (meth) acrylic acid ester having a bicyclic aliphatic hydrocarbon ring include isobornyl (meth) acrylic acid. Examples of the (meth) acrylic acid ester having three or more aliphatic hydrocarbon rings include dicyclopentanyl (meth) acrylate, dicyclopentanyloxyethyl (meth) acrylate, and tricyclopentanyl (meth) acrylate. , 1-adamantyl (meth) acrylate, 2-methyl-2-adamantyl (meth) acrylate, and 2-ethyl-2-adamantyl (meth) acrylate.

The amount of the (meth) acrylic acid alkyl ester with respect to 100 parts by mass of the total of the monomer components forming the acrylic base polymer is preferably 60 parts by mass or more, more preferably 70 parts by mass or more, and further preferably 75 parts by mass or more. The amount of the (meth) acrylic acid alkyl ester with respect to 100 parts by mass of the total of the monomer components forming the acrylic base polymer is preferably 100 parts by mass or less, more preferably 95 parts by mass or less, and further preferably 92 parts by mass or less.

The acrylic base polymer preferably contains a polar group-containing monomer in addition to the above-mentioned (meth) acrylic acid alkyl ester as a monomer component. Examples of the polar group-containing monomer include a hydroxy group-containing monomer, a carboxy group-containing monomer, and a nitrogen-containing monomer. When the monomer component contains a polar group-containing monomer, the cohesive force of the polymer is enhanced, and the adhesive retention at high temperature tends to be improved. Further, when a crosslinked structure is introduced into an acrylic base polymer by a crosslinking agent such as an isocyanate crosslinking agent or an epoxy crosslinking agent, the hydroxy group or the carboxy group becomes the introduction point of the crosslinked structure.

Examples of the hydroxy group-containing monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, and 6-hydroxyhexyl (meth) acrylate. Examples include 8-hydroxyoctyl acrylate, 10-hydroxydecyl (meth) acrylate, and 12-hydroxylauryl (meth) acrylate. From the viewpoint of ensuring the adhesive strength of the pressure-sensitive adhesive layer 21 and suppressing the white turbidity of the pressure-sensitive adhesive layer 21 in a high humidity environment, the hydroxy group-containing monomers include 2-hydroxyethyl acrylate and acrylic acid 4. -Hydroxybutyl is preferred.

Examples of the carboxy group-containing monomer include (meth) acrylic acid, (meth) carboxyethyl acrylate, (meth) carboxypentyl acrylate, itaconic acid, maleic acid, fumaric acid, and crotonic acid.

Examples of the nitrogen-containing monomer include a nitrogen-containing vinyl-based monomer and a cyanoacrylate monomer. Examples of the nitrogen-containing vinyl-based monomer include N-vinylpyrrolidone, methylvinylpyrrolidone, vinylpyridine, vinylpiperidone, vinylpyrimidine, vinylpiperazine, vinylpyrazine, vinylpyrrole, vinylimidazole, vinyloxazole, vinylmorpholine, and (meth) acryloylmorpholine. , N-vinylcarboxylic acid amides, and N-vinylcaprolactam. Examples of the cyanoacrylate-based monomer include acrylonitrile and methacrylonitrile. From the viewpoint of ensuring a cohesive force in the pressure-sensitive adhesive layer 21 and realizing a good adhesive force, N-vinylpyrrolidone is preferably used as the nitrogen-containing monomer.

From the viewpoint of ensuring good adhesive strength in the optical pressure-sensitive adhesive sheet 20 or the pressure-sensitive adhesive layer 21, the amount of the polar group-containing monomer is preferably 5 parts by mass or more, more preferably 5 parts by mass or more, based on 100 parts by mass of the total monomer components of the acrylic base polymer. It is 8 parts by mass or more, more preferably 10 parts by mass or more. The amount of the polar group-containing monomer with respect to 100 parts by mass of the total monomer components of the acrylic base polymer is preferably 25 parts by mass or less, more preferably 20 parts by mass or less, still more preferably 17 parts by mass or less, and particularly preferably 15 parts by mass. It is less than a part.

The monomer component forming the acrylic base polymer preferably contains a hydroxy group-containing monomer as a polar group-containing monomer component. Such a configuration is suitable for ensuring good adhesive strength in the pressure-sensitive adhesive layer 21, and is also suitable for suppressing white turbidity of the pressure-sensitive adhesive layer 21 in a high humidity environment. Further, the monomer component forming the acrylic base polymer preferably contains a nitrogen-containing monomer as a polar group-containing monomer component. Such a configuration is suitable for ensuring good adhesive strength in the pressure-sensitive adhesive layer 21.

The amount of the hydroxy group-containing monomer with respect to 100 parts by mass of the total of the monomer components is preferably 2 parts by mass or more, more preferably 3 parts by mass or more, and further preferably 4 parts by mass or more. The amount of the hydroxy group-containing monomer with respect to 100 parts by mass of the total monomer components is preferably 15 parts by mass or less, more preferably 12 parts by mass or less, and further preferably 10 parts by mass or less. In particular, the total amount of 2-hydroxyethyl acrylate and 4-hydroxybutyl acrylate is preferably in such a range, and the amount of 4-hydroxybutyl acrylate is more preferably in such a range.

The amount of the nitrogen group-containing monomer with respect to 100 parts by mass of the total monomer components of the acrylic base polymer is preferably 2 parts by mass or more, more preferably 3 parts by mass or more, and further preferably 4 parts by mass or more. The amount of the nitrogen group-containing monomer with respect to 100 parts by mass of the total monomer components of the acrylic base polymer is preferably 20 parts by mass or less, more preferably 15 parts by mass or less, still more preferably 12 parts by mass or less. In particular, the amount of N-vinylpyrrolidone is preferably in such a range.

When the optical adhesive sheet 20 is used for adhering a touch panel sensor, it is preferable that the optical adhesive sheet 20 has a small acid content in order to prevent corrosion of the electrodes due to an acid component. Further, when the optical pressure-sensitive adhesive sheet 20 is used for adhering a polarizing plate, it is preferable that the optical pressure-sensitive adhesive sheet 20 has a small acid content in order to suppress polyene formation of a polyvinyl alcohol-based polarizing element by an acid component. The content of the organic acid monomer such as (meth) acrylic acid in such an acid-free optical pressure-sensitive adhesive sheet 20 is preferably 100 ppm or less, more preferably 70 ppm or less, still more preferably 50 ppm or less. The organic acid monomer content of the optical pressure-sensitive adhesive sheet 20 is determined by immersing the optical pressure-sensitive adhesive sheet 20 in pure water and heating it at 100 ° C. for 45 minutes, thereby quantifying the acid monomer extracted into water by an ion chromatograph. Demanded by.

From the viewpoint of reducing the acid monomer content in the optical pressure-sensitive adhesive sheet 20, it is preferable that the amount of the organic acid monomer component such as (meth) acrylic acid in the monomer component constituting the base polymer is small. Therefore, in order to make the optical pressure-sensitive adhesive sheet 20 acid-free, it is preferable that the base polymer does not substantially contain an organic acid monomer (carboxy group-containing monomer) as a monomer component. In the acid-free pressure-sensitive adhesive sheet, the amount of the carboxy group-containing monomer with respect to 100 parts by mass of the total monomer components of the base polymer is preferably 0.5 parts by mass or less, more preferably 0.1 parts by mass or less, still more preferably 0. It is 05 parts by mass or less, ideally 0.

The acrylic base polymer may contain a monomer other than the above-mentioned (meth) acrylic acid alkyl ester and a polar group-containing monomer as a monomer component. Examples of other monomer components include vinyl-based monomers other than the above, cyanoacrylate-based monomers other than the above, glycol-based acrylic ester monomers, and acrylic acid ester-based monomers other than the above. Examples of vinyl-based monomers other than the above include caprolactone adducts of (meth) acrylic acid, sulfonic acid group-containing monomers, phosphoric acid group-containing monomers, vinyl acetate, vinyl propionate, styrene, and α-methylstyrene. Examples of the cyanoacrylate-based monomer other than the above include acrylonitrile and methacrylonitrile. Examples of the epoxy group-containing monomer include glycidyl (meth) acrylate. Examples of the glycol-based acrylic ester monomer include polyethylene glycol (meth) acrylate, polypropylene glycol (meth) acrylate, methoxyethylene glycol (meth) acrylate, and methoxypolypropylene glycol (meth) acrylate. Examples of the acrylic acid ester-based monomer other than the above include tetrahydrofurfuryl (meth) acrylic acid, fluorine (meth) acrylate, and silicone (meth) acrylate.

As the glass transition temperature (Tg) of the polymer, the glass transition temperature (theoretical value) obtained based on the following Fox formula can be used. The Fox formula is a relational expression between the glass transition temperature Tg of the polymer and the glass transition temperature Tgi of the homopolymer of the monomer constituting the polymer. In the Fox formula below, Tg represents the glass transition temperature (° C.) of the polymer, Wi represents the weight fraction of the monomer i constituting the polymer, and Tgi represents the glass transition of the homopolymer formed from the monomer i. Indicates the 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) and "New Polymer Bunko 7 Introduction to Synthetic Resins for Paints". (Kyozo Kitaoka, Polymer Publications, 1995) lists the glass transition temperatures of various homopolymers. As the Tg of the homopolymer of the monomer, the peak top temperature of the loss tangent (tan δ) obtained by the dynamic viscoelasticity measurement may be adopted. A specific method for measuring the peak top temperature is described in, for example, Japanese Patent Application Laid-Open No. 2007-51271.

Fox formula 1 / (273 + Tg) = Σ [Wi / (273 + Tgi)]

The gel fraction can be determined as an insoluble fraction in a solvent such as ethyl acetate. Specifically, the gel fraction is determined as the weight fraction (unit: mass%) of the insoluble component after immersing the pressure-sensitive adhesive layer as a sample in ethyl acetate at 23 ° C. for 7 days with respect to the sample before immersion. Be done. In general, the higher the degree of cross-linking of a polymer, the higher the gel fraction of the polymer tends to be. The gel fraction (introduction amount of the crosslinked structure) can be adjusted, for example, by selecting the method for introducing the crosslinked structure, selecting the type of the crosslinking agent, and the amount of the crosslinking agent used.

As a method for introducing a cross-linked structure into the base polymer, for example, a method of polymerizing a base polymer having a functional group capable of reacting with the cross-linking agent and then adding a cross-linking agent to react the base polymer with the cross-linking agent (No. 1). 1) and a method (second method) of introducing a branched structure (crosslinked structure) into the polymer chain by including a polyfunctional compound in the polymer component of the base polymer. These may be used in combination to introduce a plurality of crosslinked structures into the base polymer.

In the first method, a cross-linking structure is introduced into the base polymer by adding a cross-linking agent to the polymerized base polymer and heating as necessary. Examples of the cross-linking agent include compounds that react with functional groups (for example, hydroxy groups and carboxy groups) contained in the base polymer. Examples of the cross-linking agent include an isocyanate cross-linking agent, an epoxy cross-linking agent, an oxazoline cross-linking agent, an aziridine cross-linking agent, a carbodiimide cross-linking agent, and a metal chelate cross-linking agent.

As the cross-linking agent in the first method, an isocyanate cross-linking agent and an epoxy cross-linking agent are used because they have high reactivity with the functional groups (for example, hydroxy group and carboxy group) of the base polymer and the cross-linking structure can be easily introduced. preferable. These cross-linking agents react with functional groups (eg, hydroxy and carboxy groups) introduced into the base polymer to form a cross-linked structure. In an acid-free pressure-sensitive adhesive in which the base polymer does not contain a carboxy group, it is preferable to use an isocyanate cross-linking agent to form a cross-linked structure by reacting the hydroxy group in the base polymer with the isocyanate cross-linking agent.

As the isocyanate cross-linking agent, for example, polyisocyanate having two or more isocyanate groups in one molecule is used. Examples of the isocyanate cross-linking agent include lower aliphatic polyisocyanates, alicyclic isocyanates, aromatic isocyanates, and isocyanate adducts. Examples of the lower aliphatic polyisocyanates include butylene diisocyanate and hexamethylene diisocyanate. Examples of alicyclic isocyanates include cyclopentylene diisocyanate, cyclohexylene diisocyanate, and isophorone diisocyanate. Examples of aromatic isocyanates include 2,4-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, and xylylene diisocyanate. Examples of the isocyanate additive include a trimethylol propane / tolylene diisocyanate trimer adduct (for example, “Coronate L” manufactured by Tosoh) and a trimethylol propane / hexamethylene diisocyanate trimer adduct (for example, “Coronate L” manufactured by Tosoh). Coronate HL ”), trimethylol propane adduct of xylylene diisocyanate (eg,“ Takenate D110N ”manufactured by Mitsui Chemicals, Inc.), and isocyanurates of hexamethylene diisocyanate (eg,“ Coronate HX ”manufactured by Toso).

In the second method, the monomer component constituting the acrylic base polymer and the total amount of the polyfunctional compound for introducing the crosslinked structure may be reacted (polymerized) at one time or polymerized in multiple steps. good. In the multi-step polymerization method, for example, first, the monofunctional monomers constituting the base polymer are polymerized (prepolymerized) to prepare a partial polymer (prepolymer composition). Next, a polyfunctional compound such as a polyfunctional (meth) acrylate is added to the prepolymer composition to polymerize (mainly polymerize) the prepolymer composition and the polyfunctional monomer. The prepolymer composition is a partial polymer containing a polymer having a low degree of polymerization and an unreacted monomer.

By prepolymerizing the constituent components of the acrylic base polymer, branch points (crosslinking points) due to the polyfunctional compound can be uniformly introduced into the base polymer. Further, a mixture (adhesive composition) of a low molecular weight polymer or a partial polymer and an unpolymerized monomer component is applied onto a substrate and then main-polymerized on the substrate to form an optical pressure-sensitive adhesive sheet 20. You can also. Since low-polymerization compositions such as prepolymer compositions have low viscosity and excellent coatability, the method of main polymerization on a substrate after coating a tacky composition which is a mixture of a prepolymer composition and a polyfunctional compound is used. It is preferable from the viewpoint of productivity of the optical pressure-sensitive adhesive sheet 20 and from the viewpoint of uniform thickness.

Examples of the polyfunctional compound used for introducing the crosslinked structure include compounds containing two or more polymerizable functional groups (ethylenically unsaturated groups) having an unsaturated double bond in one molecule. As the polyfunctional compound, polyfunctional (meth) acrylate is preferable because it can be easily copolymerized with the monomer component of the acrylic base polymer. When a branched (crosslinked) structure is introduced by active energy ray polymerization (photopolymerization), a polyfunctional acrylate is preferable.

Examples of the polyfunctional (meth) acrylate include polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, polytetramethylene glycol di (meth) acrylate, bisphenol A ethylene oxide-modified di (meth) acrylate, and bisphenol A. Propylene oxide modified di (meth) acrylate, alkanediol di (meth) acrylate, tricyclodecanedimethanol di (meth) acrylate, ethoxylated isocyanuric acid tri (meth) acrylate, pentaeristol tri (meth) acrylate, pentaeristol Di (meth) acrylate, trimethylol propanetri (meth) acrylate, ditrimethylol propanetetra (meth) acrylate, ethoxylated pentaeristol tetra (meth) acrylate, pentaeristol tetra (meth) acrylate, dipentaeristol poly ( Examples include meth) acrylates, dipentaerystollhexa (meth) acrylates, neopentyl glycol di (meth) acrylates, glycerin di (meth) acrylates, epoxy (meth) acrylates, butadiene (meth) acrylates, and isoprene (meth) acrylates. Be done.

The molecular weight of a polyfunctional compound such as a polyfunctional (meth) acrylate is preferably 1500 from the viewpoint of appropriately adjusting viscoelasticity (for example, storage elastic modulus G'and loss tangent tan δ) by introducing a crosslinked structure in an acrylic base polymer. Below, it is more preferably 1000 or less. The functional group equivalent (g / eq) of the polyfunctional compound is preferably 50 or more, more preferably 70 or more, still more preferably 80. The functional group equivalent is preferably 500, more preferably 300 or less, still more preferably 200.

Examples of the polymerization method of the acrylic base polymer include solution polymerization, active energy ray polymerization method, bulk polymerization, and emulsion polymerization. A solution polymerization method and an active energy ray polymerization method (for example, UV polymerization) are preferable in terms of the transparency, water resistance, and cost of the pressure-sensitive adhesive. Examples of the solvent for solution polymerization include ethyl acetate and toluene.

In preparing the acrylic base polymer, a polymerization initiator may be used depending on the type of polymerization reaction. Examples of the polymerization initiator include a photopolymerization initiator and a thermal polymerization initiator. Examples of the photopolymerization initiator include a benzoin ether-based photopolymerization initiator, an acetophenone-based photopolymerization initiator, an α-ketol-based photopolymerization initiator, an aromatic sulfonyl chloride-based photopolymerization initiator, and a photoactive oxime-based photopolymerization initiator. Agents, benzoin-based photopolymerization initiators, benzyl-based photopolymerization initiators, benzophenone-based photopolymerization initiators, ketal-based photopolymerization initiators, thioxanthone-based photopolymerization initiators, and acylphosphine oxide-based photopolymerization initiators. Be done. Examples of the thermal polymerization initiator include an azo-based initiator, a peroxide-based initiator, and a redox-based initiator in which a peroxide and a reducing agent are combined (for example, a combination of a persulfate and sodium bisulfite). And a combination of peroxide and sodium ascorbate).

In the polymerization, for example, from the viewpoint of adjusting the molecular weight, a chain transfer agent and a polymerization inhibitor (polymerization retarder) may be used. Examples of the chain transfer agent include thiols such as α-thioglycerol, lauryl mercaptan, glycidyl mercaptan, mercaptoacetic acid, 2-mercaptoethanol, thioglycolic acid, 2-ethylhexyl thioglycolate, and 2,3-dimercapto-1-propanol. , And α-methylstyrene dimer.

The molecular weight of the base polymer can be adjusted by adjusting the type and amount of the polymerization initiator. For example, in radical polymerization, the larger the amount of the polymerization initiator, the higher the radical concentration of the reaction system, so that the density of the reaction starting point tends to be high and the polymer molecular weight tends to be small. On the contrary, as the amount of the polymerization initiator is smaller, the density of the reaction initiation point is smaller, so that the polymer chain tends to be easily extended and the polymer molecular weight tends to be large.

In order to achieve high adhesive strength in the pressure-sensitive adhesive layer 21, it is preferable that the acrylic base polymer has a high gel fraction with a small crosslink point density. In order to increase the gel fraction (ratio of polymer chains into which the crosslinked structure is introduced) with a small crosslink density, the molecular weight (length of the polymer chain) of the base polymer may be increased. In order to increase the molecular weight of the base polymer, it is preferable to reduce the amount of the polymerization initiator used when polymerizing the base polymer.

The amount of the polymerization initiator used during the polymerization of the base polymer is appropriately set according to, for example, the type of the polymerization reaction, the composition of the monomer, the type of the polymerization initiator, and the target molecular weight. From the viewpoint of increasing the molecular weight of the base polymer and increasing the gel content with a small amount of cross-linking agent, the amount of the polymerization initiator used is preferably 0.001 with respect to a total of 100 parts by mass of the monomer components constituting the base polymer. By mass or more, more preferably 0.003 parts by mass or more, still more preferably 0.005 parts by mass or more. The amount used is preferably 0.4 parts by mass or less, more preferably 0.1 parts by mass or less, and further preferably 0.05 parts by mass or less.

When introducing a crosslinked structure with an isocyanate cross-linking agent, after polymerizing the base polymer by solution polymerization, the cross-linking agent is added to the polymerization solution, and the solution is heated as necessary to introduce the cross-linked structure into the base polymer. Is preferable. When a crosslinked structure is introduced by a polyfunctional compound such as a polyfunctional (meth) acrylate, the base polymer is polymerized or a prepolymer composition is prepared by solution polymerization or active energy ray polymerization, and the polyfunctional compound is added to the polymerization solution. It is preferable to add and introduce a crosslinked structure by a polyfunctional compound by further active energy ray polymerization.

The prepolymer composition can be prepared, for example, by partially polymerizing (prepolymerizing) a composition (composition for forming a prepolymer) in which a monomer component constituting an acrylic base polymer and a polymerization initiator are mixed. The monomer component in the composition for forming a prepolymer is preferably a monofunctional monomer component among the monomer components constituting the acrylic base polymer. The monofunctional monomer component is, for example, the above-mentioned (meth) acrylic acid alkyl ester and a polar group-containing monomer. The composition for forming a prepolymer may contain a polyfunctional monomer in addition to the monofunctional monomer. For example, a part of the polyfunctional monomer may be contained in the composition for forming a prepolymer, and the remainder of the polyfunctional monomer component may be added after the prepolymerization to carry out the main polymerization.

The polymerization rate of the prepolymer is not particularly limited, but is preferably 3% by mass or more, more preferably 5% by mass or more, and preferably 50% by mass from the viewpoint of obtaining a viscosity suitable for coating on a substrate. As mentioned above, it is more preferably 40% by mass or less. The polymerization rate of the prepolymer can be adjusted by selecting the type of photopolymerization initiator and adjusting the amount used, and adjusting the irradiation intensity and irradiation time of active energy rays such as UV light.

The pressure-sensitive adhesive sheet may contain an oligomer in addition to the acrylic-based polymer. The weight average molecular weight of the acrylic oligomer is, for example, 1000 or more, and for example, 30,000 or less. The acrylic oligomer contains a (meth) acrylic acid alkyl ester as a main constituent monomer component.

From the viewpoint of enhancing the adhesive strength of the pressure-sensitive adhesive sheet, the glass transition temperature of the acrylic oligomer is preferably 60 ° C. or higher, more preferably 80 ° C. or higher, still more preferably 100 ° C. or higher, and particularly preferably 110 ° C. or higher. The combined use of the low Tg acrylic base polymer introduced with the crosslinked structure and the high Tg acrylic oligomer tends to improve the adhesive strength in the pressure-sensitive adhesive layer 21, and particularly tends to improve the adhesive holding power at high temperatures. be. The glass transition temperature of the acrylic oligomer is preferably 200 ° C. or lower, more preferably 180 ° C. or lower, still more preferably 160 ° C. or lower. The glass transition temperature of the acrylic oligomer is calculated by the above Fox formula.

The acrylic oligomer having a glass transition temperature of 60 ° C. or higher preferably has a (meth) acrylic acid alkyl ester having a linear or branched alkyl group and / or an alicyclic alkyl group as a constituent monomer component. Contains (meth) acrylic acid alkyl esters. Specific examples of these are as described above as constituent monomers of the acrylic base polymer.

In the acrylic oligomer, as the (meth) acrylic acid alkyl ester having a linear or branched alkyl group, methyl methacrylate is preferable because it has a high glass transition temperature and is excellent in compatibility with a base polymer. Examples of the (meth) acrylic acid alkyl ester having an alicyclic alkyl group include dicyclopentanyl acrylate, dicyclopentanyl methacrylate, cyclohexyl acrylate, and cyclohexyl methacrylate. Preferably, the acrylic oligomer contains, as constituent monomer components, one or more selected from the group consisting of dicyclopentanyl acrylate, dicyclopentanyl methacrylate, cyclohexyl acrylate, and cyclohexyl methacrylate, and methyl methacrylate. include.

The amount of the (meth) acrylic acid alkyl ester having a linear or branched alkyl group with respect to the total amount of the monomer components constituting the acrylic oligomer is preferably 10% by mass or more, more preferably 20% by mass or more, still more preferably. It is 30% by mass or more, preferably 90% by mass or less, more preferably 80% by mass or less, and further preferably 70% by mass or less. The amount of the (meth) acrylic acid alkyl ester having an alicyclic alkyl group with respect to the total amount of the monomer components constituting the acrylic oligomer is preferably 10% by mass or more, more preferably 20% by mass or more, still more preferably 30% by mass. % Or more, preferably 90% by mass or less, more preferably 80% by mass or less, still more preferably 70% by mass or less.

The weight average molecular weight of the acrylic oligomer is preferably 1000 or more, more preferably 1500 or more, still more preferably 2000. The weight average molecular weight is preferably 30,000 or less, more preferably 10,000 or less, still more preferably 8,000 or less. Acrylic oligomers having a molecular weight in such a range are suitable for achieving good adhesive strength and adhesive retention in the pressure-sensitive adhesive layer 21.

The acrylic oligomer can be obtained by polymerizing the above-mentioned monomer components by various polymerization methods. Various polymerization initiators may be used in the polymerization of the acrylic oligomer. Further, a chain transfer agent may be used in the polymerization reaction from the viewpoint of adjusting the molecular weight.

From the viewpoint of sufficiently enhancing the adhesive strength of the pressure-sensitive adhesive layer 21, the amount of the acrylic oligomer in the pressure-sensitive adhesive layer 21 with respect to 100 parts by mass of the base polymer is preferably 0.5 parts by mass or more, more preferably 0.8 parts by mass or more. More preferably, it is 1 part by mass or more. The amount of the acrylic oligomer in the pressure-sensitive adhesive layer 21 is 1.3 parts by mass or more and 1.5 parts by mass or more and 1.8 parts by mass or more and 2 parts by mass or more and 2.3 parts by mass with respect to 100 parts by mass of the base polymer. It may be 2 parts or more, or 2.5 parts by mass or more. The larger the amount of the high Tg acrylic oligomer added, the better the adhesive strength of the pressure-sensitive adhesive layer 21 tends to be.

When the amount of the acrylic oligomer added to the pressure-sensitive adhesive layer 21 is excessively large, the haze of the pressure-sensitive adhesive layer 21 tends to increase due to the decrease in compatibility, and the transparency tends to decrease. Since the optical adhesive sheet arranged on the visual side of the image display panel is required to have high transparency, the amount of the acrylic oligomer in the optical adhesive sheet 20 (adhesive layer 21) is based on 100 parts by mass of the base polymer. It is preferably 10 parts by mass or less, more preferably 7 parts by mass or less, still more preferably 6 parts by mass or less, and particularly preferably 5 parts by mass or less.

The acrylic base polymer (or prepolymer composition) is mixed with the acrylic oligomer, a cross-linking agent and / or a polyfunctional compound for introducing a cross-linking structure, and other additives to be blended as needed. , Prepare an adhesive composition for forming the adhesive layer 21. If necessary, the residue of the monomer component constituting the acrylic base polymer may be added to the adhesive composition. A thickening additive or the like may be used for the purpose of adjusting the viscosity.

When the tacky composition contains a prepolymer composition and a polyfunctional compound, it is preferable to add a photopolymerization initiator and a chain transfer agent for the main polymerization to the tacky composition. After the prepolymerization, a polymerization initiator for the main polymerization may be added to the prepolymer composition. If the polymerization initiator during the prepolymerization remains in the prepolymer composition without being deactivated, the addition of the polymerization initiator for the main polymerization may be omitted. The tacky composition may contain a chain transfer agent.

The content of the acrylic base polymer (or prepolymer composition) in the adhesive composition is preferably 50% by mass or more, more preferably 70% by mass, and 80% by mass or more with respect to the total amount of the non-volatile content. It is more preferable, and it is particularly preferable that it is 90% by mass or more.

The amount of the cross-linking agent and / or the polyfunctional compound in the tacky composition is adjusted so that the gel fraction is within the above range. As described above, in order to obtain the pressure-sensitive adhesive layer 21 having a small storage elastic modulus G'and excellent adhesive strength, it is necessary to increase the molecular weight of the acrylic base polymer and increase the gel fraction with a small cross-linking point density. preferable. For example, when the cross-linking structure is introduced with an isocyanate cross-linking agent, the amount of the cross-linking agent is preferably 0.005 part by mass or more, more preferably 0.01 part by mass or more, still more preferably, with respect to 100 parts by mass of the acrylic base polymer. Is 0.02 parts by mass. The amount of the cross-linking agent is preferably 0.5 parts by mass or less, more preferably 0.3 parts by mass or less, and further preferably 0.1 parts by mass or less. When the crosslinked structure is introduced by the polyfunctional (meth) acrylate, the amount of the polyfunctional (meth) acrylate is preferably 0.005 part by mass or more, more preferably 0.005 part by mass with respect to 100 parts by mass of the acrylic base polymer (prepolymer). It is 0.01 part by mass or more, more preferably 0.02 part by mass or more. The amount of the polyfunctional (meth) acrylate is preferably 0.3 parts by mass or less, more preferably 0.2 parts by mass or less, and further preferably 0.1 part by mass or less.

From the viewpoint of adjusting the adhesive strength of the pressure-sensitive adhesive layer 21, a silane coupling agent may be added to the pressure-sensitive adhesive composition. When a silane coupling agent is added to the adhesive composition, the amount of the silane coupling agent added is preferably 0.01 part by mass or more, more preferably 0.03 part by mass with respect to 100 parts by mass of the base polymer. It is more than parts, preferably 5.0 parts by mass or less, and more preferably 2.0 parts by mass or less.

The adhesive composition may contain components other than the above. Other components include, for example, tackifiers, plasticizers, softeners, antioxidants, fillers, colorants, UV absorbers, antioxidants, surfactants, and antistatic agents.

The optical pressure-sensitive adhesive sheet 20 can be manufactured, for example, by applying the above-mentioned pressure-sensitive adhesive composition on a separator 10 (separator 10A) to form a coating film, and then drying the coating film.

Examples of the method of applying the adhesive composition include 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 coat. , And die coat. The drying temperature of the coating film is, for example, 50 ° C to 200 ° C. The drying time is, for example, 5 seconds to 20 minutes.

When the tacky composition contains a cross-linking agent, the cross-linking reaction proceeds by aging at the same time as or after the above-mentioned drying. The aging conditions are appropriately set depending on the type of the cross-linking agent. The aging temperature is, for example, 20 ° C to 160 ° C. The aging time is, for example, 1 minute to 7 days.

Further, it is preferable to further laminate the separator 10 (separator 10B) on the pressure-sensitive adhesive layer 21 on the separator 10A before or after aging.

When the adhesive composition is a photopolymerizable composition containing a prepolymer composition, a polyfunctional compound, or the like, the adhesive composition is applied in layers on the separator 10 and then photocured by irradiating with active light. Is done. When photo-curing, a cover sheet may be attached to the surface of the coating layer, and the adhesive composition may be irradiated with active light while sandwiched between the two sheets to prevent polymerization inhibition due to oxygen. preferable.

The active light is selected according to the type of monomer component, polymerizable component (eg, polyfunctional (meth) acrylate), and type of photopolymerization initiator. Generally, ultraviolet light and / or short wavelength visible light is used. The integrated light amount of the irradiation light is, for example, about 100 to 5000 mJ / cm ² . As the light source for light irradiation, a light source capable of irradiating light in a wavelength range in which the photopolymerization initiator contained in the adhesive composition has sensitivity is used. Examples of the light source include an LED light source, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a metal halide lamp, and a xenon lamp.

As described above, the optical adhesive sheet X with a separator can be manufactured. The optical pressure-sensitive adhesive sheet X with a separator is preferably manufactured in a clean room. The higher the air cleanliness (for example, the air cleanliness in a clean room) in the production line of the optical adhesive sheet X with a separator, the smaller the amount of environmental foreign matter inside and the surface of the optical adhesive sheet X with a separator, and the size of the environmental foreign matter. Is small. The air cleanliness of the production line is preferably class 3 or less, more preferably class 2 or less, still more preferably class 1 in the ISO 14644-1 standard.

The thickness of the pressure-sensitive adhesive layer 21 is preferably 10 μm or more, more preferably 15 μm or more, from the viewpoint of ensuring sufficient adhesiveness to the adherend. From the viewpoint of handleability of the optical pressure-sensitive adhesive sheet 20, the thickness of the pressure-sensitive adhesive layer 21 is preferably 300 μm or less, more preferably 200 μm or less.

The haze of the pressure-sensitive adhesive layer 21 is preferably 3% or less, more preferably 2% or less. The haze of the pressure-sensitive adhesive layer 21 can be measured using a haze meter in accordance with JIS K7136 (2000). Examples of the haze meter include "NDH2000" manufactured by Nippon Denshoku Kogyo Co., Ltd. and "HM-150 type" manufactured by Murakami Color Technology Research Institute.

The transmittance of the light emitted from the white LED light source in the pressure-sensitive adhesive layer 21 is, for example, 50% or more, preferably 80% or more, and more preferably 90% or more. Such a configuration is preferable from the viewpoint of appropriately performing a foreign matter inspection using a white LED light source. The infrared transmittance of the pressure-sensitive adhesive layer 21 is, for example, 50% or more, preferably 80% or more, and more preferably 90% or more. Such a configuration is preferable from the viewpoint of appropriately performing a foreign matter inspection using infrared rays.

The present invention will be specifically described below with reference to examples, but the present invention is not limited to the examples. In addition, the specific numerical values such as the compounding amount (content), the physical property value, the parameter, etc. described below are the compounding amounts corresponding to them described in the above-mentioned "form for carrying out the invention" (forms for carrying out the invention). It can be replaced with an upper limit (numerical value defined as "less than or equal to" or "less than") or a lower limit (numerical value defined as "greater than or equal to" or "greater than or equal to") such as content), physical property value, and parameter.

[Example 1]
<Making a separator>
Example 1 by forming a silicone-based release layer on one side of a cycloolefin polymer (COP) film (trade name "Zeonoa film ZF16", thickness 50 μm, manufactured by Zeon Corporation) as a base film in a clean room. (Two separators were prepared in this way). The air cleanliness in the clean room is class 3 in the ISO 14644-1 standard. In the formation of the silicone-based release layer, first, 30 parts by mass of an additive-type silicone composition (trade name "LTC761", manufactured by Toray Dow Corning) and a silicone dispersion (trade name "BY 24-850", Toray Co., Ltd.) A mixture of 0.9 parts by mass of Dow Corning and 2 parts by mass of a platinum catalyst for curing silicone (trade name "SRX 212", manufactured by Toray Dow Corning) is mixed with a mixed solvent of toluene and hexane (toluene and hexane). The volume ratio was diluted by 1: 1) to prepare a release agent solution. Next, this solution was applied to one surface of a COP film having a thickness of 50 μm, and heat-dried for 1 minute in a hot air dryer at 130 ° C. As a result, the separator of Example 1 was produced. The separator of Example 1 includes a COP film as a base film and a silicone release layer on one surface thereof.

<Making an optical adhesive sheet with a separator>
In a clean room, first, an ultraviolet curable adhesive composition is applied to a release layer forming surface in one of the separators of Example 1 (the first separator as a support release film) to coat a coating film (thickness). 50 μm) was formed. Next, the other separator of Example 1 (the second separator as a cover release film) was laminated on the exposed surface of the coating film to obtain a laminated body. The laminated body was irradiated with ultraviolet rays from the second separator side to photo-cure the adhesive composition coating film to form an adhesive layer. As the light source for ultraviolet irradiation, a black light whose position was adjusted so that the irradiation intensity on the irradiation surface directly under the lamp was 5 mW / cm ² was used. As described above, the optical pressure-sensitive adhesive sheet with a separator of Example 1 was produced. The optical pressure-sensitive adhesive sheet with a separator has a photocurable pressure-sensitive adhesive layer and separators arranged on both sides.

[Example 2]
With the separator of Example 1 except that a filler-less polyethylene terephthalate (PET) film (trade name "38-U41", thickness 38 μm, manufactured by Toray Industries, Inc.) was used as the base film of the separator instead of the COP film. The optical pressure-sensitive adhesive sheet with a separator of Example 2 was produced in the same manner as the optical pressure-sensitive adhesive sheet.

[Comparative Example 1]
Example 1 except that a biaxially stretched polyester film (trade name "Lumirror XD500P", thickness 75 μm, filler-containing film, manufactured by Toray Advanced Materials Korea) was used as the base film of the separator instead of the COP film. The optical pressure-sensitive adhesive sheet with a separator of Comparative Example 1 was produced in the same manner as the optical pressure-sensitive adhesive sheet with a separator.

[Comparative Example 2]
Example 1 except that a biaxially stretched polypropylene film (trade name "Trefan # 30-2500H", thickness 75 μm, filler-containing film, manufactured by Toray Industries, Inc.) was used as the base film for the separator instead of the COP film. The optical pressure-sensitive adhesive sheet with a separator of Comparative Example 2 was produced in the same manner as the optical pressure-sensitive adhesive sheet with a separator.

[Comparative Example 3]
Example 1 except that a biaxially stretched polyester film (trade name "Diafoil T100C50", thickness 50 μm, filler-containing PET film, manufactured by Mitsubishi Chemical Co., Ltd.) was used as the base film for the separator instead of the COP film. The optical pressure-sensitive adhesive sheet with a separator of Comparative Example 3 was produced in the same manner as the optical pressure-sensitive adhesive sheet with a separator.

<Measurement of foreign matter on optical adhesive sheet with separator>
The amount and size of foreign matter were examined for each of the optical pressure-sensitive adhesive sheets with separators of Examples 1 and 2 and Comparative Examples 1 to 3. Specifically, the foreign matter area ratio, the bubble area ratio, the foreign matter maximum length L1 and the foreign matter maximum length L2 obtained by the following evaluation methods were investigated.

[Evaluation methods]
The following first to third steps were carried out using an evaluation device including the following light source and camera device.

Light source: White LED light source for irradiating the evaluation sample with inspection light Camera device: The sample transmitted light and sample reflected light of the inspection light are arranged so as to be able to be imaged, and have a resolution of 2.8 μm. Camera device

<First step>
First, the optical adhesive sheet with a separator having a plan view size of 50 mm × 50 mm was prepared as a sample for evaluation. Next, the sample was set in the evaluation device in a state where the inner region (30 mm × 30 mm) surrounded by the outer region of the sample could be imaged by the camera device. In this step, the sample is set in the evaluation device by having the chuck mechanism provided in the evaluation device grip the outer region of the sample.

<Second step>
The sample set in the evaluation device was irradiated with the inspection light from the white LED light source, and the sample transmitted light and the sample reflected light were received by the camera device over the entire inner region. As a result, the received light data was acquired over the inner region.

<Third step>
Using the received light data, the position information and the projected image information of the foreign matter (each of the foreign matter existing in the inner region) on the projection surface of the plan view projection in the inner region were derived. The position information derived in the third step includes XY coordinate information with the projection plane as the XY plane and Z coordinate information with the thickness direction orthogonal to the XY plane as the Z direction. Is done. The projection image information derived in the third step is information that can derive the total area of the foreign matter, the size of each foreign matter, and the size distribution of the foreign matter based on the projection image information.

The foreign matter area ratio is the ratio of the total projected area of foreign matter on the projection surface of the plan view projection by the above evaluation method (that is, the above-mentioned foreign matter area ratio R2). Regarding this foreign matter area ratio, when it is 10% or less, it is evaluated as "excellent", when it exceeds 10% and 20% or less, it is evaluated as "good", and when it exceeds 20%, it is evaluated as "bad". evaluated. The evaluation results are shown in Table 1. It can be evaluated that the above-mentioned foreign matter area ratio R1 is 10% or less for the optical pressure-sensitive adhesive sheets with separators of Examples 1 and 2 in which the foreign matter area ratio is 10% or less and is evaluated as “excellent”.

The bubble area ratio is the ratio of the total projected area of the bubbles on the projection surface of the plan view projection (that is, the bubble area ratio R4 described above). Regarding this bubble area ratio, when it is 5% or less, it is evaluated as "excellent", when it exceeds 5% and 10% or less, it is evaluated as "good", and when it exceeds 10%, it is evaluated as "poor". evaluated. The evaluation results are shown in Table 1. It can be evaluated that the above-mentioned bubble area ratio R3 is 10% or less for the optical pressure-sensitive adhesive sheets with separators of Examples 1 and 2 in which the bubble area ratio is 10% or less and is evaluated as “excellent”.

The foreign matter maximum length L1 is the maximum length of the foreign matter that is the largest in the plan view projection. Regarding the maximum foreign matter length L1, when it is less than 15 μm, it is evaluated as “excellent”, when it is 15 μm or more and 30 μm or less, it is evaluated as “good”, and when it is more than 30 μm and 50 μm or less, it is evaluated as “possible”. Evaluation was performed, and a case exceeding 50 μm was evaluated as “defective”. The evaluation results are shown in Table 1.

The foreign matter maximum length L2 is the maximum length of the maximum foreign matter between the separator and the optical adhesive sheet (adhesive layer) in the plan view projection. Regarding the maximum foreign matter length L2, when it is less than 15 μm, it is evaluated as “excellent”, when it is 15 μm or more and 30 μm or less, it is evaluated as “good”, and when it is more than 30 μm and 50 μm or less, it is evaluated as “possible”. Evaluation was performed, and a case exceeding 50 μm was evaluated as “defective”. The evaluation results are shown in Table 1.

<Measurement of foreign matter on separator>
The amount and size of foreign matter were examined for each separator (before forming the pressure-sensitive adhesive layer) in Examples 1 and 2 and Comparative Examples 1 to 3. Specifically, the ratio of the foreign matter area obtained by the above evaluation method, the maximum length of the foreign matter, the number N1 of the foreign matter in the first range, and the number N2 of the foreign matter in the second range were investigated.

The foreign matter area ratio is the ratio of the total projected area of foreign matter on the projection surface of the plan view projection by the above evaluation method with respect to the separator (that is, the foreign matter area ratio R5 described above). Regarding this foreign matter area ratio, when it is 10% or less, it is evaluated as "excellent", when it exceeds 10% and 20% or less, it is evaluated as "good", and when it exceeds 20%, it is evaluated as "bad". evaluated. The evaluation results are shown in Table 2.

The foreign matter maximum length is the maximum length of the foreign matter that is the largest in the plan view projection of the separator (that is, the foreign matter maximum length L3 described above). Regarding the maximum length of foreign matter, the case of 15 μm or less is evaluated as “excellent”, the case of exceeding 15 μm and 30 μm or less is evaluated as “good”, and the case of exceeding 30 μm and 50 μm or less is “possible”. It was evaluated as "defective" when it exceeded 50 μm. The evaluation results are shown in Table 2.

The number N1 is the number of foreign substances having a maximum length of 20 μm or more and 30 μm or less in the plan view projection of the separator. The number N2 is the number of foreign substances having a maximum length of 15 μm or more and 30 μm or less in the plan view projection of the separator. These are shown in Table 2. In each separator in Comparative Examples 1 to 3, N1 exceeded 20 and N2 exceeded 100.

<Surface roughness of separator>
The surface roughness of each separator in Examples 1 and 2 and Comparative Examples 1 to 3 was examined. Specifically, first, the surface roughness Ra (arithmetic mean roughness) of the exposed surface of the release layer of the separator was measured by a scanning white interferometer (trade name "NewView7300", manufactured by Zygо) at 0.7 mm × 0. It was obtained from an observation image of .52 mm. Further, the surface roughness Rz (ten-point average roughness) of the exposed surface of the release layer of the separator was obtained from an observation image of 0.7 mm × 0.52 mm by the scanning white meter. Table 2 shows each surface roughness Ra and Rz (nm).

X Optical adhesive sheet with separator 10, 10A, 10B Separator 11 Base film 12, 12A, 12B Release layer 20 Optical adhesive sheet 21 Adhesive layer

Claims (9)

An optical pressure-sensitive adhesive sheet with a separator, comprising a pressure-sensitive adhesive layer and a separator arranged on one side in the thickness direction of the pressure-sensitive adhesive layer.
The ratio of the total projected area of foreign matter having a maximum length of 15 μm or more and 30 μm or less on the projection surface of the plan view projection by the following evaluation method is 20% or less, and the number of foreign matter having a maximum length of 30 μm or more is 1 or less. An optical adhesive sheet with a separator.
Evaluation method: The following first to third steps are carried out using a device including the following light source and camera device.
Light source: White LED light source for irradiating the sample for evaluation with inspection light Camera device: The sample transmitted light and sample reflected light of the inspection light are arranged so as to be able to be imaged, and the resolution is 2.8 μm or less. First step of camera device: The optical pressure-sensitive adhesive sheet with a separator having a plan view size of 50 mm × 50 mm is prepared as a sample for evaluation, and an inner region (30 mm × 30 mm) surrounded by an outer region in the sample is used. The sample is set in the device in a state where it can be imaged by the camera device.
Second step: While irradiating the sample with inspection light from the white LED light source, the camera device is used to receive the sample transmitted light and / or the sample reflected light, and the received light data is transmitted over the inner region. get.
Third step: Using the received light data, the position information and the projected image information of the foreign matter on the projection surface of the plan view projection of the inner region are derived. The optical pressure-sensitive adhesive sheet with a separator according to claim 1, further comprising a separator arranged on the other side in the thickness direction of the pressure-sensitive adhesive layer. The optical adhesive sheet with a separator according to claim 1 or 2, wherein the number of foreign substances is 10 or less. The optical pressure-sensitive adhesive sheet with a separator according to any one of claims 1 to 3, wherein the maximum length of the maximum foreign matter in the plan view projection is 15 μm or more and 30 μm or less. The optical adhesive sheet with a separator according to any one of claims 1 to 4, wherein the ratio of the total projected area of bubbles having a maximum length of 15 μm or more and 30 μm or less on the projection surface of the plan view projection is 10% or less. .. The optical pressure-sensitive adhesive sheet with a separator according to claim 5, wherein the number of bubbles is 0. The optical pressure-sensitive adhesive sheet with a separator according to any one of claims 1 to 6, wherein the maximum length of the maximum bubble in the plan view projection is 15 μm or more and 30 μm or less. The optical pressure-sensitive adhesive sheet with a separator according to any one of claims 1 to 7, wherein the separator is a ratio of the total projected area of foreign substances on the projection surface of the plan view projection to 20% or less. The optical pressure-sensitive adhesive sheet with a separator according to any one of claims 1 to 8, wherein the separator has a surface having a surface roughness Ra of 20 nm or less.

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