KR20240024042A - Manufacturing method and optical laminate of optical laminate - Google Patents

Abstract

The manufacturing method of the optical laminate includes step A of preparing a first optical sheet having a first main surface having a concavo-convex structure, process B of preparing an adhesive layer, and bonding the adhesive layer to the first main surface of the first optical sheet. Includes process C. The uneven structure includes a plurality of concave portions and flat portions between adjacent concave portions. Each of the plurality of concave portions has an inclined surface at an inclination angle θa. The stress obtained by dividing the 180° peel adhesion of the adhesive layer to the first main surface of the first optical sheet by the 180° peel test by the film cross-sectional area is Sp. In step C, the pressure when bonding the adhesive layer to the first main surface of the first optical sheet is set to Pl. In step C, the pressure applied to the flat portion when bonding the adhesive layer to the first main surface of the first optical sheet is set to Pf. If Sp When the strain corresponding to Sp×sinθa in the stress-strain curve is multiplied by the thickness Dt of the adhesive layer as Dd, Dd is 1.3 μm or less.

Description

Manufacturing method and optical laminate of optical laminate

The present invention relates to a method of manufacturing an optical laminate and an optical laminate.

Optical sheets (e.g., microlens sheets, prism sheets, brightness enhancement films (e.g., Brightness Enhancement Film: BEF, (registered trademark) manufactured by 3M)) are used in various optical devices (e.g., display devices and lighting) device). In this specification, the term “optical sheet” is not limited to those exemplified above, but broadly includes sheet-shaped optical members, and further includes, for example, a diffusion plate and a light guide plate. The optical sheet is attached to another optical sheet or optical device, for example using an adhesive layer. In this specification, a configuration including an optical sheet and an adhesive layer or a configuration including a plurality of optical sheets is referred to as an “optical laminate.” In this specification, “adhesive” is used to include adhesive (also referred to as “pressure-sensitive adhesive”).

The present applicant discloses in Patent Document 1 an optical laminated body (referred to as an “optical laminated sheet” in Patent Document 1) that can be used in a display device or lighting device. The optical laminate of Patent Document 1 has an optical sheet (for example, a microlens sheet) having an uneven structure on its surface, and an adhesive layer formed on the surface having an uneven structure. 5% to 90% of the height of the convex portion of the uneven structure is filled with an adhesive layer. The adhesive layer is formed of an adhesive composition containing a graft polymer obtained by graft polymerizing a chain containing a cyclic ether group-containing monomer to a (meth)acrylic polymer, and a photocationic polymerization initiator or a thermosetting catalyst.

Additionally, Patent Documents 2 and 3 disclose a light distribution structure that utilizes total reflection by the interface of a plurality of air cavities, which can be used in a display device or lighting device. By using the light distribution structure disclosed in Patent Documents 2 and 3, the degree of freedom and precision of light distribution control can be improved. The entire disclosures of Patent Documents 2 and 3 are incorporated herein by reference.

Japanese Patent Publication No. 2012-007046 International Publication No. 2011/124765 International Publication No. 2019/087118

When attaching an adhesive layer to the surface of an optical sheet having a concavo-convex structure, the extent to which the adhesive layer penetrates (fills the concave portion) the concave-convex structure affects the function of the optical sheet. Therefore, it is required that the extent to which the adhesive layer invades the recesses of the uneven structure (the ratio of the volume of the adhesive layer existing in the space to the volume of the space defined by the recessed parts of the uneven structure) is suppressed.

In addition, the present inventor constitutes the light distribution structure (light distribution control structure) described in Patent Documents 2 and 3 by the surface of the optical sheet having an uneven structure and the surface of the adhesive layer attached to the surface of the optical sheet having an uneven structure. We considered forming a plurality of air cavities (internal spaces). Patent Documents 2 and 3 do not describe that a plurality of air cavities (internal spaces) constituting a light distribution structure are formed by the surface having the concavo-convex structure of the optical sheet and the surface of the adhesive layer.

The present invention was made to solve the above problems, and its purpose is to provide a method for manufacturing an optical laminate having an adhesive layer with a suppressed degree of intrusion into the recesses of the concavo-convex structure of an optical sheet, and to provide such an optical laminate. .

According to embodiments of the present invention, solutions described in the following items are provided.

[Item 1]

A first optical sheet having a first main surface having a concavo-convex structure and a second main surface opposite to the first main surface, wherein the concavo-convex structure includes a plurality of concave portions and a flat portion between adjacent concave portions among the plurality of concave portions. Process A of preparing a first optical sheet comprising,

Process B of preparing an adhesive layer,

Comprising a step C of bonding the adhesive layer to the first main surface of the first optical sheet,

Each of the plurality of concave portions has an inclined surface at an inclination angle θa,

The stress obtained by dividing the 180° peel adhesive force of the adhesive layer with respect to the first main surface of the first optical sheet, obtained by a 180° peel test, by the film cross-sectional area is Sp,

In the step C, the pressure when bonding the adhesive layer to the first main surface of the first optical sheet is set to Pl,

In the step C, the pressure applied to the flat portion when bonding the adhesive layer to the first main surface of the first optical sheet is set to Pf,

When Sp

In the case of Sp

A method for producing an optical laminate wherein Dd is 1.3 μm or less.

[Item 2]

The manufacturing method according to item 1, wherein Dd is 0.5 μm or less.

[Item 3]

The manufacturing method according to item 1 or 2, wherein the pressure Pl in step C is 0.1 MPa or more and 0.5 MPa or less.

[Item 4]

The manufacturing method according to any one of items 1 to 3, wherein the thickness Dt of the adhesive layer is 3 μm or more and 10 μm or less.

[Item 5]

The manufacturing method according to any one of items 1 to 4, wherein the compressive stress (y)-strain (x) curve of the adhesive layer is approximated by y=a× ^xb , a is 150 or more, and b is 2 or more.

[Item 6]

The manufacturing method according to item 5, wherein the compressive stress (y)-strain (x) curve of the adhesive layer is approximated by y=a×x ^b , and a is 250 or more.

[Item 7]

The manufacturing method according to any one of items 1 to 4, wherein the compressive stress (y)-strain (x) curve of the adhesive layer is approximated by y=a× ^xb , a is 30 or less, and b is 2 or more.

[Item 8]

The production method according to any one of items 1 to 7, satisfying Sp×sinθa<Pf.

[Item 9]

The manufacturing method according to any one of items 1 to 8, wherein the stress Sp is 0.5 MPa or less.

[Item 10]

The manufacturing method according to any one of items 1 to 8, wherein the stress Sp is 1.0 MPa or more.

[Item 11]

The adhesive layer is,

It is formed by crosslinking an adhesive composition containing a polyester resin that is a copolymer of a polyhydric carboxylic acid and a polyhydric alcohol, a crosslinking agent, and at least one crosslinking catalyst selected from the group consisting of an organic zirconium compound, an organic iron compound, and an organic aluminum compound. ,

The gel fraction is over 40% after being maintained for 300 hours at a temperature of 85°C and a relative humidity of 85%.

The manufacturing method according to any one of items 1 to 10, wherein the 180° peel adhesion to the PMMA film is 100 mN/20 mm or more.

[Item 12]

The manufacturing method according to any one of items 1 to 10, wherein the adhesive layer is the following adhesive layer Aa or adhesive layer Ab.

In a creep test using a rotational rheometer, the creep strain rate when a stress of 10,000 Pa was applied for 1 second at 50°C was 10% or less, and the creep strain rate when a stress of 10,000 Pa was applied for 30 minutes at 50°C was 16%. Below,

Adhesive layer Aa, having a 180° peel adhesion to PMMA film of 10 mN/20 mm or more;

An adhesive composition containing a polymer and a curable resin is formed by curing the curable resin,

The initial tensile modulus of elasticity at 23°C before curing the curable resin of the adhesive composition is 0.35 MPa or more and 8.00 MPa or less,

Adhesive layer Ab, wherein the initial tensile modulus of elasticity at 23°C after curing the curable resin of the adhesive composition is 1.00 MPa or more.

[Item 13]

The manufacturing method according to any one of items 1 to 12, wherein the inclined surface directs a part of light propagating within the adhesive layer toward the second main surface side of the first optical sheet by total internal reflection.

[Item 14]

Each of the plurality of concave portions has a different inclined surface opposite to the inclined surface,

The manufacturing method according to any one of items 1 to 13, wherein the inclination angle θa of the inclined surface is smaller than the inclination angle θb of the other inclined surface.

[Item 15]

The process B is,

An adhesive composition solution containing a (meth)acrylic polymer and/or polyester polymer, a crosslinking agent, and a solvent is applied on the peeled main surface of a base material having a peeled main surface to form an adhesive composition solution layer. process Ba,

Step Bb of removing the solvent of the adhesive composition solution layer to form an adhesive composition layer,

A step Bc of forming another substrate having a peeling-treated main surface on the main surface opposite to the base material of the adhesive composition layer so that the peeling-treated main surface is in contact with the adhesive composition layer;

A step Bd of forming the adhesive layer by crosslinking the (meth)acrylic polymer and/or polyester polymer of the adhesive composition layer with the crosslinking agent,

The process C is,

The manufacturing method according to any one of items 1 to 14, comprising a step Ca of bonding the first main surface of the first optical sheet and the main surface of one side of the base material of the adhesive layer or the other base material.

[Item 16]

The manufacturing method according to item 15, wherein the arithmetic mean roughness Ra of the peeling-treated main surface of the substrate or the other substrate is less than 0.05 μm.

[Item 17]

The manufacturing method according to item 16, wherein the maximum height Rz of the peeled main surface of the substrate or the other substrate is less than 0.5 μm.

[Item 18]

The manufacturing method according to any one of items 15 to 17, wherein the step Ca is performed by a roll-to-roll method.

[Item 19]

When the ratio of the area of the plurality of concave portions to the area when the first optical sheet is viewed in a planar direction from the normal direction of the first main surface is Rr,

The manufacturing method according to any one of items 1 to 18, wherein the pressure Pf applied to the flat portion in the step C is obtained by dividing the pressure Pl in the step C by (1-Rr).

[Item 20]

A first optical sheet having a first main surface having a concavo-convex structure and a second main surface opposite to the first main surface, wherein the concavo-convex structure includes a plurality of concave portions and a flat portion between adjacent concave portions among the plurality of concave portions. a first optical sheet comprising,

It has an adhesive layer disposed on the first main surface side of the first optical sheet and in contact with the flat portion,

The surface of the adhesive layer and the first main surface of the first optical sheet define an internal space within each of the plurality of recesses,

Each of the plurality of concave portions has an inclined surface at an inclination angle θa,

The adhesive layer is attached to the first main surface of the first optical sheet with pressure Pl,

When bonding the adhesive layer to the first main surface of the first optical sheet, the pressure applied to the flat portion is Pf,

The stress obtained by dividing the 180° peel adhesive force of the adhesive layer with respect to the first main surface of the first optical sheet, obtained by a 180° peel test, by the film cross-sectional area is Sp,

When Sp

In the case of Sp

An optical laminate having a Dd of 1.3 μm or less.

[Item 21]

The adhesive layer is,

It is formed by crosslinking an adhesive composition containing a polyester resin that is a copolymer of a polyhydric carboxylic acid and a polyhydric alcohol, a crosslinking agent, and at least one crosslinking catalyst selected from the group consisting of an organic zirconium compound, an organic iron compound, and an organic aluminum compound. ,

The gel fraction is over 40% after being maintained for 300 hours at a temperature of 85°C and a relative humidity of 85%.

The optical laminate according to item 20, wherein the optical laminate has a 180° peel adhesion to a PMMA film of 100 mN/20 mm or more.

[Item 22]

The optical laminate according to item 20, wherein the adhesive layer is the following adhesive layer Aa or adhesive layer Ab.

In a creep test using a rotational rheometer, the creep strain rate when a stress of 10,000 Pa was applied for 1 second at 50°C was 10% or less, and the creep strain rate when a stress of 10,000 Pa was applied at 50°C for 30 minutes was 16%. Below,

Adhesive layer Aa, having a 180° peel adhesion to PMMA film of 10 mN/20 mm or more;

An adhesive composition containing a polymer and a curable resin is formed by curing the curable resin,

The initial tensile modulus of elasticity at 23°C before curing the curable resin of the adhesive composition is 0.35 MPa or more and 8.00 MPa or less,

Adhesive layer Ab, wherein the initial tensile modulus of elasticity at 23°C after curing the curable resin of the adhesive composition is 1.00 MPa or more.

According to an embodiment of the present invention, a method for manufacturing an optical laminate having an adhesive layer with a suppressed degree of penetration into the recesses of the uneven structure of an optical sheet and such an optical laminate are provided.

1A is a schematic cross-sectional view of an optical laminate 100A according to an embodiment of the present invention.
FIG. 1B is a schematic cross-sectional view of an optical laminate 101A according to another embodiment of the present invention.
Figure 2 is a schematic cross-sectional view of the optical laminate 100A.
FIG. 3 is a schematic perspective view of the first optical sheet 10a included in the optical laminated body 100A.
FIG. 4A is a schematic cross-sectional view of a lighting device 200A including an optical laminate 100A.
FIG. 4B is a schematic cross-sectional view of a lighting device 200B including an optical laminate 100A.
FIG. 5 is a diagram schematically showing a process for manufacturing the optical laminate 100A using a roll-to-roll method.
FIG. 6 is a diagram schematically showing a process for manufacturing the optical laminate 100A using a roll-to-roll method.
FIG. 7A is a schematic diagram for explaining problems when manufacturing the optical laminate of the reference example by a roll-to-roll method.
FIG. 7B is a schematic diagram for explaining problems when manufacturing the optical laminate of the reference example by a roll-to-roll method.
FIG. 8A is a diagram schematically showing an example of a process for manufacturing the optical laminate 100A.
FIG. 8B is a diagram schematically showing an example of a process for manufacturing the optical laminate 100A.
Fig. 9A is a schematic plan view of the concavo-convex shape film 70 included in the optical laminate according to the embodiment of the present invention.
FIG. 9B is a schematic cross-sectional view of the concavo-convex shape film 70.
Figure 10 is a graph showing evaluation results of the area ratio (%) of bubbles and the height (μm) of the adhesive layer present in the concave portion in the optical laminate of the example.
FIG. 11A is a schematic diagram for explaining a method of evaluating changes in the degree of penetration into the concave portion of the adhesive layer using an optical laminate.
FIG. 11B is a schematic cross-sectional view for explaining a method of evaluating changes in the degree of penetration into the concave portion of the adhesive layer using an optical laminate.
Figure 12 is an optical image of the sample 1000A having the optical laminate 100S of Example A, the upper part is an optical image of the sample 1000A before applying force, and the middle part is an optical image of the sample 1000A when force is applied. The optical image at the bottom is a diagram showing the optical image of the sample (1000A) after the force has been removed.
Figure 13 is an optical image of a sample having the optical laminate of Example B, where the top is an optical image of the sample before applying force, the middle is an optical image of the sample when force is applied, and the bottom is an optical image of the sample after the force is removed. This is a drawing showing the optical image of .
Fig. 14A is a schematic plan view of the concavo-convex shape film 52 included in the optical laminate according to the embodiment of the present invention.
FIG. 14B is a schematic cross-sectional view of the concavo-convex shape film 52.
Fig. 15A is a schematic plan view of the concavo-convex shape film 82 included in the optical laminate according to the embodiment of the present invention.
FIG. 15B is a schematic cross-sectional view of the concave portion 84 of the concavo-convex shape film 82.
FIG. 15C is a schematic plan view of the concave portion 84 of the concavo-convex shape film 82.
Fig. 16A is a schematic diagram for explaining the calculation method of the calculated embedding amount Dd of the adhesive layer.
FIG. 16B is a schematic diagram for explaining the calculation method of the calculated embedding amount Dd of the adhesive layer.
Fig. 16C is a schematic diagram for explaining the calculation method of the calculated embedding amount Dd of the adhesive layer.
Figure 17 is a graph showing the correlation between the measured value (μm) of the height of the adhesive layer present in the concave portion and the calculated embedding amount Dd (μm).
Figure 18 is a schematic perspective view for explaining a method of measuring the compressive stress-strain curve of an adhesive layer.
Figure 19a is a schematic cross-sectional view for explaining a method of measuring the 180° peel adhesion of the adhesive layer to the optical sheet.
Figure 19b is a schematic top view for explaining a method of measuring the 180° peel adhesion of the adhesive layer to the optical sheet.
Figure 19c is a schematic cross-sectional view for explaining a method of measuring the 180° peel adhesion of the adhesive layer to the optical sheet.

An optical laminate and an optical device having the optical laminate according to an embodiment of the present invention will be described. Embodiments of the present invention are not limited to those illustrated below.

An optical laminate according to an embodiment of the present invention has an optical sheet having a first main surface having an uneven structure and a second main surface opposite to the first main surface, and an adhesive layer disposed on the first main surface side of the optical sheet. First, referring to FIGS. 1A, 1B, 2, 3, 4A, and 4B, the adhesive layer attached to the surface (first main surface) having the concavo-convex structure of the optical sheet penetrates into the concave portion of the concavo-convex structure. Explain an example of what is not being done.

FIG. 1A shows a schematic cross-sectional view of an optical laminated body 100A according to an embodiment of the present invention. FIG. 1B shows a schematic cross-sectional view of an optical laminated body 101A according to an embodiment of the present invention. FIG. 2 is a schematic cross-sectional view showing an enlarged portion of the optical laminated body 100A. FIG. 3 is a schematic perspective view of the optical sheet 10a included in the optical laminated body 100A. FIG. 4A is a schematic cross-sectional view of a lighting device 200A including an optical laminate 100A.

As shown in FIG. 1A, the optical laminated body 100A is a first optical sheet 10a having a first main surface 12s having an uneven structure and a second main surface 18s on the opposite side to the first main surface 12s. and an adhesive layer 20a disposed on the first main surface 12s side of the first optical sheet 10a. The uneven structure of the first main surface 12s includes a plurality of recessed parts 14 and a flat part 10s between adjacent recessed parts 14 among the plurality of recessed parts 14. The adhesive layer 20a is in contact with the flat portion 10s. The surface of the adhesive layer 20a and the first main surface 12s of the first optical sheet 10a define an internal space 14a within each of the plurality of recesses 14.

As shown in FIG. 1B, the optical layered body 101A has an optical layered body 100A and a second optical sheet 30 disposed on the side opposite to the first optical sheet 10a side of the adhesive layer 20a. . Since the description of the optical laminated body 100A is also applicable to the optical laminated body 101A unless specifically mentioned, the description may be omitted to avoid duplication.

The second optical sheet 30 of the optical laminated body 101A has a main surface 38s on the adhesive layer 20a side, and a main surface 32s on the opposite side to the main surface 38s. The main surface 38s is a flat surface. At least one other optical member (or optical sheet) may be disposed on the side opposite to the adhesive layer 20a of the second optical sheet 30 of the optical laminated body 101A (that is, on the main surface 32s). Other optical members (optical sheets) include, for example, a diffusion plate, a light guide plate, etc., and are bonded to the main surface 32s of the optical sheet 30 via an adhesive layer.

In the examples of FIGS. 1A and 2 , the adhesive layer 20a does not penetrate into the concave portion 14 . That is, the adhesive layer 20a does not exist in the space defined by the concave portion 14. The space defined by the concave portion 14 is defined by the sheet surface (plane parallel to the XY plane) including the concave portion 14 and the flat portion 10s adjacent to the concave portion 14. It refers to a space that becomes Therefore, the inner space 14a defined by the surface 28s of the adhesive layer 20a on the first optical sheet 10a side and the first main surface 12s of the first optical sheet 10a is in this example. coincides with the space defined by the concave portion 14. The internal space 14a is sometimes called an air cavity or an optical cavity. The internal space 14a is typically a void filled with air. However, the internal space 14a may be filled with a material having a lower refractive index than the first optical sheet 10a and the adhesive layer 20a instead of air. The plurality of internal spaces is a continuous internal space in the X direction (for example, a triangular prism extending in the The grooves on the top may be formed discretely in the Y direction, or may be formed discretely in an island shape in both the X and Y directions, as in the example of FIG. 9A. In addition, as shown in FIGS. 4A and 4B described later, in the lighting device including the optical laminate 100A, the light guiding direction of the light guiding layer 80 is the -Y direction. Additionally, although light propagates in various directions within the light guide layer 80, the -Y direction is referred to as the light guide direction, and light with a component in the -Y direction (not zero) is assumed to be propagating in the -Y direction.

The optical laminate 100A functions as a light distribution structure described in Patent Documents 2 and 3. The optical laminate 100A has a plurality of internal spaces 14a forming an interface that directs light toward the Z direction (lower side in the figure) by total internal reflection. The internal space 14a includes the surface 16s and the surface 17s that are part of the first main surface 12s of the first optical sheet 10a, and the surface of the adhesive layer 20a on the first optical sheet 10a side. It is defined by (28s). Here, the cross-sectional shape (shape of the cross-section perpendicular to the X direction and parallel to the YZ plane) of the internal space 14a is triangular. The interface formed by the inclined surface 16s functions as an interface that directs light toward the Z direction (lower side in the figure) by total internal reflection. Each of the plurality of recesses 14, that is, each of the plurality of internal spaces 14a, transfers a portion of the light propagating within the optical laminate 100A to the second main surface of the first optical sheet 10a by total internal reflection. It has an inclined surface (first inclined surface) 16s facing toward the (18s) side (Z direction in the drawing) and an inclined surface (second inclined surface) 17s on the opposite side to the inclined surface 16s. The inclination angle θa of the inclined surface 16s is, for example, 10° or more and 70° or less. The lower limit is preferably 30° or more, more preferably 45° or more. If the inclination angle θa is less than 10°, the controllability of light distribution may decrease and the light extraction efficiency may also decrease. On the other hand, when the inclination angle θa exceeds 70°, for example, processing of an uneven shaped film may become difficult. Additionally, the inclination angle θb of the inclined surface 17s is, for example, 50° or more and 100° or less. The lower limit is preferably 70° or more. If the tilt angle θb is smaller than 50°, stray light may occur in an unintended direction. On the other hand, when the inclination angle θb exceeds 100°, for example, processing of an uneven shaped film may become difficult. The inclination angle θa of the inclined surface 16s and the inclination angle θb of the inclined surface 17s are relative to the direction parallel to the Y direction in the cross section of the concave portion 14 (a cross section perpendicular to the X direction and parallel to the YZ plane). It's an angle. In this example, the inclination angle θa of the inclined surface 16s is smaller than the inclination angle θb of the inclined surface 17s. In the lighting device having the optical laminate 100A (see FIGS. 4A and 4B), the inclined surface 16s is disposed closer to the light source 60 than the inclined surface 17s. The cross-sectional shape of the internal space 14a (cross-section perpendicular to the It is stipulated. The shape of the internal space 14a (recessed portion 14) is not limited to the example and can be changed in various ways. By adjusting the shape, size, arrangement density, etc. of the internal space 14a (recessed portion 14), the distribution (light distribution) of light emitted from the optical laminate 100A can be adjusted (for example, patent document 2 and 3).

An optical laminate that functions as a light distribution control structure may constitute a light guide layer and/or a direction conversion layer having a plurality of internal spaces. For example, as shown in FIG. 4A, the optical laminate 100A is used in the lighting device 200A. The lighting device 200A includes an optical laminate 102A and a light source 60. The optical laminated body 102A has an optical laminated body 100A and a light guide layer 80 formed on the side opposite to the first optical sheet 10a side of the adhesive layer 20a of the optical laminated body 100A. The light guide layer 80 is adhered to, for example, the surface 22s of the adhesive layer 20a on the opposite side to the first optical sheet 10a side. The light guide layer 80 has a first main surface 80a, a second main surface 80b on the opposite side from the first main surface 80a, and a light receiving portion 80c that receives the light emitted from the light source 60. The light source 60 is, for example, an LED device, and a plurality of LED devices may be arranged and used. A portion of the light guided into the light guide layer 80 undergoes total internal reflection (TIR) at the interface 16s and the interface 14s formed by the internal space 14a, as indicated by arrows in FIG. 4A. The light totally internally reflected at the interface 14s (surface 28s on the first optical sheet side of the adhesive layer 20a) propagates within the light guide layer 80 and the adhesive layer 20a, and is transmitted on the inclined surface 16s. The totally internally reflected light is emitted from the second main surface 18s side of the first optical sheet 10a to the outside of the optical laminated body 102A.

Here, it is preferable that the refractive indices of the light guide layer 80, the adhesive layer 20a, and the first optical sheet 10a are approximately the same. The difference in refractive index (absolute value) between the light guide layer 80 and the adhesive layer 20a and the difference in refractive index (absolute value) between the adhesive layer 20a and the first optical sheet 10a are each independently, for example. 0.20 or less is preferable, 0.15 or less is more preferable, and 0.10 or less is still more preferable.

The thickness of the adhesive layer 20a is, for example, 2.0 μm or more and 15.0 μm or less. The lower limit is preferably 4.0 μm or more. The upper limit is preferably 11.0 μm or less, and more preferably 9.0 μm or less. Unless otherwise specified, the thickness of the adhesive layer 20a refers to the thickness on the flat portion 10s of the first main surface 12s of the first optical sheet 10a.

The haze value of the optical laminate 100A is, for example, 5.0% or less. The haze value can be measured with D65 light, for example, using a haze meter (device name "HZ-1", manufactured by Suga Shikenki Co., Ltd.).

Like the lighting device 200B shown in FIG. 4B, the light guide layer 80 is located on the first optical sheet 10a side of the optical laminated body 100A (to the first optical sheet 10a rather than the adhesive layer 20a). It may be formed closely). The light guide layer 80 and the first optical sheet 10a may be attached through an adhesive layer. Also in the lighting device 200B, light totally internally reflected at the interface 14s (surface 28s on the side of the first optical sheet of the adhesive layer 20b) propagates within the adhesive layer 20a and reaches the inclined surface 16s. The totally internally reflected light is emitted from the second main surface 18s side of the first optical sheet 10a to the outside of the optical laminate 102B.

The lighting device according to the embodiment of the present invention is not limited to the examples described above and can be modified in various ways. For example, the base material layer may be formed on the side of the lighting device 200A opposite to the light guide layer 80 of the optical laminate 100A. An anti-reflection layer may be formed instead of the base material layer, and a hard coat layer (for example, pencil hardness of H or more) may be formed instead of the base material layer. An antireflection layer and/or a hard coat layer may be formed on the base material layer. Additionally, an anti-reflection layer and/or a hard coat layer may be formed on the side opposite to the exit surface of the light guide layer 80 (upper side in the figure). The antireflection layer and the hard coat layer can be formed using known materials and using known methods. A low refractive index layer may be formed between the optical laminate 102A and the base layer (or anti-reflection layer and/or hard coat layer).

In the example of the lighting device 200B, a base layer may be formed on the side opposite to the light guide layer 80 of the optical laminate 100A. Instead of the base layer, an anti-reflection layer and/or a hard coat layer (for example, pencil hardness of H or higher) may be formed, and an anti-reflection layer and/or a hard coat layer may be formed on the base layer. Additionally, an anti-reflection layer and/or a hard coat layer may be formed on the exit surface side (lower side in the figure) of the light guide layer 80. A low refractive index layer may be formed between the optical laminate 102B and the base layer (or anti-reflection layer and/or hard coat layer).

As shown in FIG. 3, when the first optical sheet 10a is viewed in plan from the normal direction of the first main surface 12s, each of the plurality of concave portions 14 extends in the It's continuing. The plurality of concave portions 14 are discretely arranged in the Y direction, and a flat portion 10s is formed between the concave portions 14 and the concave portions 14. In the Y direction, the concave portions 14 are preferably arranged periodically in the Y direction, and the pitch Py is, for example, 6 μm or more and 120 μm or less. The width Wy of the concave portion 14 is, for example, 3 μm or more and 20 μm or less, and the width Dy of the flat portion 10s is, for example, 3 μm or more and 100 μm or less. The ratio Wy/Dy of the width Wy of the concave portion 14 and the width Dy of the flat portion 10s is, for example, 0.3 or more and 7 or less. The depth C (depth in the Z direction) of the concave portion 14 is, for example, 1 μm or more and 100 μm or less. The depth C of the concave portion 14 is preferably 20 μm or less, and more preferably 12 μm or less. The depth C of the concave portion 14 is preferably 4 μm or more, more preferably 6 μm or more, and more preferably 8 μm or more.

The density of the plurality of concave portions 14 is the plurality of concave portions ( The area ratio (occupied area ratio) of 14) is preferably 0.3% or more from the viewpoint of obtaining good luminance. The area ratio occupied by the plurality of concave portions 14 is appropriately selected depending on the intended use. For example, in applications requiring transparency, it is preferably 0.3% or more and 10% or less, and more preferably 0.5% or more and 4% or less. . In applications requiring higher brightness, it is preferable to be 30% or more and 80% or less. In addition, the occupied area ratio of the plurality of concave portions 14 may be uniform, and the distance may be increased so that luminance does not decrease even if the distance from the light source (for example, the light source 60 in FIG. 4A or FIG. 4B) increases. Accordingly, the occupied area ratio may be increased.

Instead of the first optical sheet 10a, for example, the uneven shape film 70 (optical sheet) shown in FIGS. 9A and 9B may be used. The uneven shaped film 70 has a main surface with a uneven structure, and the uneven structure has a plurality of recessed parts 74 and a flat part 72s between adjacent recessed parts 74. When the concave-convex shape film 70 is viewed planarly from the direction normal to the main surface (see, for example, FIG. 9A), the plurality of concave portions 74 are arranged in discrete island shapes in both the X and Y directions. . In the shaping film 70, the size of the concave portion 74 (length L, width W: see FIGS. 9A and 9B) is preferably, for example, the length L being 10 μm or more and 500 μm or less, and the width W being It is preferable that it is 1㎛ or more and 100㎛ or less. Additionally, from the viewpoint of light extraction efficiency, the depth H is preferably 1 μm or more and 100 μm or less. The depth H of the concave portion 74 is preferably 20 μm or less, and more preferably 12 μm or less. The depth H of the concave portion 74 is preferably 4 μm or more, more preferably 6 μm or more, and more preferably 8 μm or more. When the plurality of recesses 74 are distributed uniformly and discretely, it is preferable to arrange them periodically, for example, as shown in FIG. 9A. The pitch Px is preferably, for example, 10 μm or more and 500 μm or less, and the pitch Py is preferably, for example, 10 μm or more and 500 μm or less. Furthermore, without being limited to the example of FIG. 9A, when used in a lighting device, the plurality of recesses may be discretely arranged in a direction intersecting the light guiding direction of the light guiding layer and the light guiding direction of the light guiding layer.

The density of the plurality of concave portions 74 is the ratio of the plurality of concave portions 74 occupied by the area of the concavo-convex profile film 70 when the concavo-convex profile film 70 is viewed planarly from the direction normal to the main surface (FIG. 9A). The area ratio (occupied area ratio) is preferably 0.3% or more from the viewpoint of obtaining good luminance. The occupied area ratio of the plurality of concave portions 74 is appropriately selected depending on the intended use. For example, in applications requiring transparency, it is preferably 30% or less to obtain good visible light transmittance and haze value, and is preferably 30% or less. From the viewpoint of obtaining luminance, it is preferable that it is 1% or more. The upper limit is more preferably 25% or less, and in order to obtain high visible light transmittance, 10% or less is preferable, and 5% or less is more preferable. For example, it is preferable that it is 0.3% or more and 10% or less, and it is more preferable that it is 0.5% or more and 4% or less. In applications requiring higher brightness, it is preferable to be 30% or more and 80% or less. In addition, the occupied area ratio of the plurality of concave portions 74 may be uniform, and the distance may be increased so that luminance does not decrease even if the distance from the light source (for example, the light source 60 in FIG. 4A or FIG. 4B) increases. Accordingly, the occupied area ratio may be increased.

Although the cross-sectional shape of the concave portion 14 is triangular, the cross-sectional shape of the concave portion 14 is not limited to this, and a surface that can form an interface that directs light in the Z direction by total internal reflection is shown. If you have it, it may be, for example, a square (for example, a trapezoid). Additionally, it is not limited to a polygon, and may be a shape at least partially containing a curve. The shape at least partially having a curve is, for example, a portion of the circumference of a circle or ellipse, or a shape including a combination of a plurality of curves with different curvatures.

Instead of the first optical sheet 10a, for example, the concavo-convex shape film 82 (optical sheet) shown in Fig. 15A may be used. In Figure 15a, the light sources 60 are displayed together. The concavo-convex shape film 82 has a main surface with a concavo-convex structure, and the concavo-convex structure has a plurality of concave portions 84 and a flat portion 82s between adjacent concave portions 84. Each of the plurality of concave portions 84 includes a first inclined surface 86s that directs a portion of the light propagating within the optical laminate toward the Z direction by total internal reflection, and a second inclined surface 86s on the opposite side to the first inclined surface 86s. It has an inclined surface (87s). As shown in FIG. 15A, when viewed planarly from the normal direction of the main surface having the uneven structure of the uneven shaped film 82, the first inclined surface 86s of the concave portion 84 has a curved surface that is convex toward the light source 60. It is forming. When a plurality of LED devices arranged in the In this case, the first inclined surface 86s acts uniformly on light. In addition, when a coupling optical system is installed between the light source 60 and the light receiving portion 80c of the light guide layer 80 and light with a high degree of parallelism (light with low diffusion in the Y direction) is incident, the first inclined surface (86s) may be parallel to the X direction. Preferred ranges of the size (length L, width W: see FIGS. 15B and 15C), depth H (see FIG. 15C), and pitch Px and Py of the concave portion 84 are, for example, the concavities of the concave-convex shaped film 70. It may be the same as that of part 74.

The optical laminated body 100A can be manufactured by attaching the adhesive layer 20a to the surface 12s having the concavo-convex structure of the first optical sheet 10a using, for example, a roll-to-roll method. From the viewpoint of mass production, it is preferable to manufacture the optical laminated body 100A by a roll-to-roll method as shown in FIG. 5.

As shown in Fig. 5, the first optical sheet 10a and the adhesive layer 20a are bonded to each other by rolls Ra and rolls Rb rotating in the direction of the arrow. For example, one of the rolls Ra and Rb is a driving roll, and the other is a driven roll. At this time, the pressure (nip pressure, bonding pressure, laminate pressure) applied to the first optical sheet 10a and the adhesive layer 20a between the roll Ra and the roll Rb is the TD (Transverse) of the optical laminate 100A. Direction) can change depending on the location of the direction (direction parallel to the axis of the roll (Ra) and roll (Rb)). Typically, as shown in FIG. 6, the pressure applied to the first optical sheet 10a and the adhesive layer 20a increases at both ends Ae in the TD direction compared to the central portion Ad in the TD direction. . In FIG. 6, the size of the white arrow schematically shows the magnitude of the pressure applied to the first optical sheet 10a and the adhesive layer 20a between the rolls Ra and Rb.

According to the present inventor's examination, when manufacturing the optical laminate of the reference example using the adhesive layer 90 and the first optical sheet 10a of the reference example by roll-to-roll method, the following problems occur. there is. Here, an example of manufacturing an optical laminate using a roll-to-roll method will be described using the adhesive layer 90 of the reference example instead of the adhesive layer 20a of the optical laminate 100A according to the embodiment of the present invention. .

For example, as shown in FIG. 7A, an appropriate pressure is applied to the optical sheet 10a and the adhesive layer 90 at the central portion Ad in the TD direction, that is, the adhesive layer 90 is applied to the optical sheet 10a. If the pressure is adjusted so that the adhesive layer 90 is suppressed from infiltrating the concave portion 14 while having good adhesion to the surface 12s having the concavo-convex structure, at both ends Ae in the TD direction, it A greater pressure is applied to the first optical sheet 10a and the adhesive layer 90, and the adhesive layer 90 may penetrate excessively into the concave portion 14 at both ends Ae. On the other hand, as shown in FIG. 7B, when appropriate pressure is adjusted to be applied to the optical sheet 10a and the adhesive layer 90 at both ends Ae in the TD direction, the first optical sheet ( The pressure applied to 10a) and the adhesive layer 90 becomes smaller than that, and excessive bubbles BA are generated at the interface between the flat portion 10s of the first optical sheet 10a and the adhesive layer 90, 1 There are cases where the adhesiveness of the optical sheet 10a to the surface 12s having the concavo-convex structure is insufficient. In this way, by using a conventional adhesive layer, both suppressing the adhesive layer from infiltrating into the concave portion 14 of the uneven structure and suppressing air bubbles generated at the interface between the flat portion 10s of the uneven structure and the adhesive layer are achieved. There are times when it is difficult to do so. The length in the TD direction of an optical laminate manufactured by a roll-to-roll method is, for example, several meters. The larger the length of the optical laminate in the TD direction, the more likely this problem will occur.

The present inventor has found that, as shown in FIG. 8A, the above problems described with reference to FIGS. 7A and 7B can be solved by using a predetermined adhesive layer 20a. The left arrow in Figure 8a represents the time series. When preparing the first optical sheet 10a and the adhesive layer 20a (top of FIG. 8A) and bonding the adhesive layer 20a to the surface having the concave-convex structure of the first optical sheet 10a, the uneven structure is flat. Sufficient pressure is applied to prevent excessive bubbles from forming at the interface between the portion 10s and the adhesive layer 20a. At this time, the adhesive layer 20a may temporarily and excessively invade the concave portion 14 during lamination (middle part of Fig. 8A). This is because when the pressure applied during lamination disappears, the degree of penetration (burying) of the adhesive layer 20a into the concave portion 14 decreases (bottom of FIG. 8A). An example of this adhesive layer 20a is shown in an experimental example described later. In the obtained optical laminate 100A, penetration of the adhesive layer 20a into the concave portion 14 is suppressed, and air bubbles present at the interface between the flat portion 10s of the uneven structure and the adhesive layer 20a are suppressed. It is suppressed. In the optical laminate according to one embodiment of the present invention, the flat portion 10s and the adhesive layer 20a occupy the area of the first optical sheet when viewed in a planar view from the normal direction of the first main surface of the first optical sheet. ), the area ratio of the bubbles present at the interface is 3% or less, and the height of the adhesive layer 20a present in the plurality of concave portions 14 is 2 μm or less. The height of the adhesive layer 20a present in the concave portion 14 is the adhesive in the Z direction in the cross section of the concave portion 14 (a cross section perpendicular to the X direction and parallel to the YZ plane in FIG. 1A). It is the height of the layer 20b and is obtained based on the flat portion 10s. The height of the adhesive layer 20a present in the concave portion 14 can be determined from a cross-sectional SEM image of an arbitrarily selected concave portion 14, for example, as performed in the examples described later. It can be obtained by measuring the maximum value of the height of the adhesive layer 20a. The area ratio of bubbles can be measured, for example, by the method described in the Examples described later. The area ratio of bubbles is preferably 2.5% or less, more preferably 1.5% or less, and still more preferably 0.1% or less. The height of the adhesive layer present in the plurality of concave portions is preferably 1 μm or less, and more preferably 0.6 μm or less. In addition, the optical laminate according to the embodiment of the present invention is not limited to being manufactured by a roll-to-roll method. Even in an optical laminate manufactured by a manufacturing method other than the roll-to-roll method, intrusion into the concave portion of the adhesive layer is suppressed, and air bubbles present at the interface between the flat portion and the adhesive layer are suppressed.

In addition, since the ease of generating bubbles at the interface between the flat portion of the concavo-convex structure and the adhesive layer is influenced by the surface roughness of the adhesive layer, the area ratio of bubbles may also vary depending on the surface roughness of the adhesive layer. If the surface roughness of the surface of the adhesive layer (the surface on the first optical sheet side) is large, bubbles are likely to be generated.

One of the methods of reducing the surface roughness of the surface of the adhesive layer (the surface on the side of the first optical sheet) includes the following. The adhesive layer is formed, for example, by the following method. First, an adhesive composition solution containing a (meth)acrylic polymer and/or polyester polymer, a crosslinking agent, and a solvent is applied on the peeled main surface of a base material (first separator) having a peeled main surface, thereby forming an adhesive. Form a composition solution layer. Next, the solvent in the adhesive composition solution layer is removed to form an adhesive composition layer. Subsequently, on the main surface of the adhesive composition layer opposite to the first separator side, another substrate (second separator) having a peeling-treated main surface is formed so that the peeling-treated main surface is in contact with the adhesive composition layer. Next, an adhesive layer is obtained by crosslinking the (meth)acrylic polymer and/or polyester polymer of the adhesive composition layer with a crosslinking agent. That is, here, a laminate having a laminated structure of base material (first separator)/adhesive layer/another base material (second separator) is obtained. A laminate containing a base material having a peeled main surface and an adhesive layer may be referred to as an adhesive sheet. In an embodiment of the present invention, either the main surface on the first separator side or the main surface on the second separator side of the adhesive layer thus obtained is bonded to the surface having the concavo-convex structure of the first optical sheet (concavo-convex shape film). An optical laminate can be obtained. For example, when bonding the main surface of the adhesive layer on the second separator side to the surface having the concavo-convex structure of the first optical sheet (concavo-convex shaped film), the peeled main surface of the second separator (surface on the adhesive layer side) The arithmetic mean roughness Ra is preferably less than 0.05 μm, for example, and more preferably less than 0.03 μm. The lower limit of the arithmetic mean roughness Ra is not particularly limited, but is, for example, 0.001 μm. Additionally, the maximum height Rz of the peeling-treated main surface (surface on the adhesive layer side) of the second separator is, for example, less than 0.5 μm, and is preferably less than 0.3 μm. The lower limit of the maximum height Rz is not particularly limited, but is, for example, 0.005 μm.

When manufacturing an optical laminate using a roll-to-roll method, for example, the y-direction or -y-direction of the first optical sheet 10a may be referred to as the MD (Machine Direction) direction. For example, in the example shown in FIG. 1, the inclined surface 16s with the smaller inclination angle θa of the concave portion 14 has the roll Ra and It may be arranged close to the nip portion between the rolls Rb. However, the extent to which the adhesive layer 20a penetrates into the concave portion 14 does not significantly change depending on the bonding direction.

[Evaluation of the amount of embedding in the concave part of the adhesive layer]

The present inventor found that the amount of embedding in the recessed portion of the adhesive layer (the extent to which the adhesive layer penetrates into the recessed portion) can be evaluated using the value of the “calculated embedding amount Dd” calculated by the following method. Using the calculated embedding amount Dd, it is possible to evaluate the degree of embedding in the concave portion of the adhesive layer without actually bonding the adhesive layer to the optical sheet having the concave portion on the surface.

As explained with reference to FIG. 8A, the method of manufacturing the optical laminated body 100A includes a process of preparing the first optical sheet 10a (sometimes referred to as “process A”), and the adhesive layer 20a. A process of preparing (sometimes referred to as “process B”) and a process of bonding the adhesive layer 20a to the first main surface 12s of the first optical sheet 10a (sometimes referred to as “process C”) includes). At this time, in step C, the pressure (lamination pressure) at the time of bonding the adhesive layer 20a to the first main surface 12s of the first optical sheet 10a is set to Pl. When the pressure Pl is applied, the amount of embedding in the concave portion 14 of the adhesive layer 20a (here, the maximum value of the height of the adhesive layer in the concave portion 14) becomes the largest (middle part of Fig. 8A), and Afterwards, when the pressure Pl is removed, the amount of embedding in the concave portion 14 of the adhesive layer 20a decreases (bottom of FIG. 8A). The amount of embedding in the concave portion 14 of the adhesive layer 20a when pressure Pl is applied is referred to as dmax. In addition, at the bottom of Fig. 8A, a state in which there is no embedding in the concave portion 14 of the adhesive layer 20a is shown. However, this is not limited to this, and the amount of embedding may be smaller than the middle part of Fig. 8A.

FIG. 8B is a diagram schematically showing another example of the process for manufacturing the optical laminate 100A. Depending on the type of the adhesive layer 20a, as shown at the bottom of FIG. 8B, even if the pressure Pl is removed, the amount of embedding in the concave portion 14 of the adhesive layer 20a does not decrease (or the degree of reduction is small). ) There may also be cases. In the example of FIG. 8B, compared to the example of FIG. 8A, for example, the compressive elastic modulus of the adhesive layer 20a is small.

As shown in FIG. 16A, the amount of embedding in the recess 14 of the adhesive layer 20a in the optical laminate 100A obtained in this way (that is, after a certain period of time has elapsed after the pressure Pl is removed) is: It is thought to be determined by the relationship between the restoring force F1 due to the compressive elasticity of the adhesive layer 20a at the embedding amount dmax and the stress F2 obtained from the peeling adhesive force of the adhesive layer 20a with respect to the first optical sheet 10a. .

In the step C (step of bonding the adhesive layer 20a to the first main surface 12s of the first optical sheet 10a), the adhesive layer 20a is bonded to the first main surface 12s of the first optical sheet 10a ( The pressure applied to the flat portion 10s of the first main surface 12s of the first optical sheet 10a when joining (i.e., when pressure Pl is applied) is set to Pf. The pressure Pf applied to the flat portion 10s is assumed to be such that pressure is not applied to the concave portion 14 of the first main surface 12s of the first optical sheet 10a and pressure is applied only to the flat portion 10s. , obtained by converting the lamination pressure Pl into the following equation.

Pf=Pl/(1-Rr)

Here, Pf: pressure applied to the flat portion 10s, Pl: laminate pressure, and Rr: occupied area ratio of the concave portion 14. The occupied area ratio Rr of the recessed portion 14 is a plurality of recessed portions occupying the area of the first optical sheet 10a when the first optical sheet 10a is viewed planarly from the normal direction of the first main surface 12s. It is the ratio of the area of (14). The area of the plurality of concave portions 14 when the first optical sheet 10a is viewed planarly from the normal direction of the first main surface 12s is when viewed planarly from the normal direction of the first main surface 12s. It is obtained by subtracting the area of the flat portion 10s from the area of the first optical sheet 10a.

The restoring force F1 due to compressive elasticity uses the stress Sm corresponding to the ratio (dmax/Dt) of the embedding amount dmax to the thickness Dt of the adhesive layer 20a in the compressive stress-strain curve of the adhesive layer 20a. and evaluate it. The thickness Dt of the adhesive layer 20a is the thickness of the adhesive layer 20a on the flat portion 10s of the first main surface 12s of the first optical sheet 10a. This is the thickness of the adhesive layer 20a before being attached to the main surface 12s. Here, as shown in FIG. 16B, the ratio (dmax/Dt) of the embedding amount dmax to the thickness Dt of the adhesive layer 20a is the laminate pressure Pl in the compressive stress-strain curve of the adhesive layer 20a. It can be calculated as a deformation of the pressure Pf applied to the flat portion 10s when applied (arrow (I) in FIG. 16B). Therefore, in the compressive stress-strain curve of the adhesive layer 20a, the value of stress Sm corresponding to dmax/Dt (arrow (II) in FIG. 16C) goes opposite to arrow (I) in FIG. 16B, The stress Sm can be evaluated by the pressure Pf applied to the flat portion 10s. 16B and 16C are graphs showing the compressive stress-strain curve of the adhesive layer 20a formed from the polyester adhesive composition solution A used in the examples described later, when the compressive stress is y and the strain is x. It is shown with the approximate formula y=a×x ^b (in this example, a=278, b=2.19). As shown in the examples, whether or not an approximation equation is used does not significantly affect the calculated value of dmax.

The stress F2 resulting from the peel adhesion is the stress Sp obtained by dividing the 180° peel adhesion of the adhesive layer 20a to the first optical sheet 10a, obtained by a 180° peel test, by dividing the film cross-sectional area, multiplied by sinθa (Sp Evaluate using ×sinθa). Among the stress Sp, it is a component parallel to the direction in which the laminate pressure Pl is applied.

Cases are classified based on the magnitude relationship between the restoring force F1 due to compressive elasticity and the stress F2 resulting from peeling adhesive force. (i) When the stress F2 resulting from the peeling adhesive force is greater than or equal to the restoring force F1 due to compressive elasticity (F2 ≥ F1), the calculated embedding amount Dd = dmax. In this case, as in the example of FIG. 8B, it is thought that even if the pressure Pl is removed, the amount of embedding in the concave portion 14 of the adhesive layer 20a does not change. In contrast, (ii) when the stress F2 resulting from the peeling adhesive force is smaller than the restoring force F1 due to compressive elasticity (F2<F1), the adhesive layer undergoes a deformation corresponding to F2 in the compressive stress-strain curve of the adhesive layer 20a. The value multiplied by the thickness Dt in (20a) is taken as Dd. That is, the strain corresponding to F2 in the compressive stress-strain curve of the adhesive layer 20a is assumed to be Dd/Dt, and the calculated embedding amount Dd is obtained. In this case, as in the example of FIG. 8A, when the pressure Pl is removed, the amount of embedding in the concave portion 14 of the adhesive layer 20a decreases. In addition to decreasing the amount of embedding in the concave portion 14 of the adhesive layer 20a, the restoring force due to compressive elasticity also decreases, and when the restoring force due to compressive elasticity is equal to the stress F2 resulting from the peeling adhesive force (corresponding to (when) the landfill volume is set to Dd.

When the calculated embedding amount Dd calculated by the above method was compared with the measured value of the height of the adhesive layer 20a existing in the concave portion 14, a certain correlation was confirmed, as shown in FIG. 17 described later. Using the calculated embedding amount Dd, an optical laminate in which penetration into the recessed portion 14 of the adhesive layer 20a is suppressed can be represented. Specifically, when the height (measured value) of the adhesive layer present in the concave portion 14 is 2 μm or less, the calculated embedding amount Dd can be expressed as 1.3 μm or less.

As described above, the optical laminate 100A according to this embodiment can be represented as follows.

The optical laminated body 100A includes a first optical sheet 10a having a first main surface 12s having a concavo-convex structure and a second main surface 18s on the opposite side to the first main surface 12s, and a first optical sheet ( It has an adhesive layer 20a disposed on the first main surface 12s side of 10a). The uneven structure of the first main surface 12s includes a plurality of concave portions 14 and a flat portion 10s between adjacent concave portions 14 among the plurality of concave portions 14. The adhesive layer 20a is in contact with the flat portion 10s. The surface of the adhesive layer 20a and the first main surface 12s of the first optical sheet 10a define an internal space 14a within each of the plurality of recesses 14. Each of the plurality of concave portions 14 has an inclined surface with an inclination angle θa. The adhesive layer 20a is attached to the first main surface 12s of the first optical sheet 10a by pressure Pl. The pressure applied to the flat portion 10s when bonding the adhesive layer 20a to the first main surface 12s of the first optical sheet 10a is Pf. Sp is the stress obtained by dividing the 180° peel adhesive force of the adhesive layer 20a with respect to the first main surface 12s of the first optical sheet 10a, determined by the 180° peel test, by the film cross-sectional area. In the case of Sp In this case, when the strain corresponding to Sp×sinθa in the compressive stress-strain curve of the adhesive layer 20a is multiplied by the thickness Dt of the adhesive layer 20a as Dd, Dd is 1.3 μm or less. The optical laminate 100A having such a first optical sheet 10a and an adhesive layer 20a is formed by embedding the adhesive layer 20a in the concave portion 14 of the first main surface 12s of the first optical sheet. This is suppressed.

The manufacturing method of the optical laminated body 100A according to this embodiment includes step A of preparing the first optical sheet 10a, step B of preparing the adhesive layer 20a, and the first adhesive layer 20a. It includes step C of bonding to the first main surface 12s of the optical sheet 10a. Each of the plurality of concave portions 14 has an inclined surface at an inclination angle θa. In step C, the pressure at the time of bonding the adhesive layer 20a to the first main surface 12s of the first optical sheet 10a is set to Pl. In step C, when bonding the adhesive layer 20a to the first main surface 12s of the first optical sheet 10a, the pressure applied to the flat portion 10s is set to Pf. Sp is the stress obtained by dividing the 180° peel adhesive force of the adhesive layer 20a with respect to the first main surface 12s of the first optical sheet 10a, determined by the 180° peel test, by the film cross-sectional area. In the case of Sp In this case, when the strain corresponding to Sp×sinθa in the compressive stress-strain curve of the adhesive layer 20a is multiplied by the thickness Dt of the adhesive layer 20a as Dd, Dd is 1.3 μm or less. In the optical laminated body 100A manufactured by this method, embedding of the adhesive layer 20a in the concave portion 14 of the first main surface 12s of the first optical sheet is suppressed.

The compressive stress-strain curve of the adhesive layer 20a can be obtained, for example, by the method described in the Examples. The compressive stress-strain curve of the obtained adhesive layer 20a may be approximated as y = ^a indicates). In the calculation procedure of the calculated embedding amount Dd described above, when calculating the stress or strain in the compressive stress-strain curve of the adhesive layer 20a, use this approximate formula (stress (y) or strain in the approximate formula You can calculate it by substituting (x)), or you can calculate it without using an approximation equation. When an approximate equation is not used, for example, the value may be obtained by selecting the closest value among the measurement results (data) of compressive stress and strain, or interpolation may be performed appropriately.

The 180° peel adhesive force of the adhesive layer 20a with respect to the first main surface 12s of the first optical sheet 10a, determined by the 180° peel test, and the stress Sp obtained by dividing it by the film cross-sectional area are, for example, Examples It can be obtained by the method described in .

Among the inclined surfaces of the plurality of concave portions 14, the inclined surface having the inclination angle θa is here a portion of the light propagating within the adhesive layer 20a is transferred to the second main surface 18s of the first optical sheet 10a by total internal reflection. ) side. Each of the plurality of concave portions 14 has another inclined surface (slant angle θb) on the opposite side to the inclined surface having the inclined angle θa, and the inclined angle θa is smaller than the inclined angle θb.

[Example of preferred configuration of adhesive layer]

Specific examples of the adhesive layer included in the optical laminate according to the embodiment of the present invention are given below. When the following adhesive layers Aa, Ab, and Ac are all attached to the surface having the concavo-convex structure of the optical sheet, intrusion into the concave portion of the concavo-convex structure and its change over time are suppressed, and thus optical lamination according to the embodiment of the present invention It is preferably used in sieves. In addition, the adhesive layer included in the optical laminate according to the embodiment of the present invention is not limited to the examples below.

(1) Adhesive layer Aa

In International Publication No. 2021/167090 by the present applicant, in a creep test using a rotational rheometer, the creep strain rate is 10% or less when a stress of 10,000 Pa is applied for 1 second at 50°C, and the creep strain is 10,000 Pa at 50°C. An adhesive layer (hereinafter sometimes referred to as “adhesive layer Aa”) having a creep strain of 16% or less when stress is applied for 30 minutes and a 180° peeling adhesive force to a PMMA film of 10 mN/20 mm or more is described. According to the present applicant's examination, there is a correlation between the degree of penetration into the concave portion and the change over time when the adhesive layer is attached to the surface having the concavo-convex structure of the optical sheet and the creep strain rate of the adhesive layer. Specifically, in a creep test using a rotational rheometer, an adhesive layer with a creep strain of 10% or less when a stress of 10,000 Pa is applied for 1 second at 50°C has an uneven structure when attached to a surface having an uneven structure. The degree of intrusion into the concave portion of the adhesive layer is suppressed, and in a creep test using a rotational rheometer, the adhesive layer with a creep strain of 16% or less when a stress of 10,000 Pa is applied at 50°C for 30 minutes (1800 seconds) has irregularities. Changes over time in the degree of intrusion into the recessed portion of the structure are suppressed. The entire disclosure of International Publication No. 2021/167090 is incorporated herein by reference.

(2) Adhesive layer Ab

In International Publication No. 2021/167091 by the present applicant, at least one (meth)acrylate monomer and at least one selected from the group consisting of a hydroxyl group-containing copolymerizable monomer, a carboxyl group-containing copolymerizable monomer, and a nitrogen-containing vinyl monomer It is an adhesive layer formed by curing a polymer containing a copolymer of a copolymerizable functional group-containing monomer and a curable resin of an adhesive composition containing a curable resin, and the initial tensile modulus of elasticity at 23° C. before curing the curable resin of the adhesive composition is An adhesive layer (hereinafter sometimes referred to as “adhesive layer Ab”) is described, which is 0.35 MPa or more and 8.00 MPa or less, and the initial tensile modulus of elasticity at 23°C after curing the curable resin of the adhesive composition is 1.00 MPa or more. Since the initial tensile modulus of elasticity at 23°C before curing the curable resin of the adhesive composition is 0.35 MPa or more, when forming the adhesive layer 20a, that is, the adhesive composition layer is formed on the first main surface 12s of the optical sheet 10a. When applying, the adhesive composition is suppressed from entering the plurality of recesses. Since the initial tensile modulus of elasticity at 23°C of the adhesive composition before curing the curable resin of the adhesive composition is 8.00 MPa or less, the adhesive composition layer is provided on the first main surface 12s of the optical sheet 10a. It has the necessary flexibility (ease of modification). Since the initial tensile modulus of elasticity at 23°C after curing the curable resin of the adhesive composition is 1.00 MPa or more, after the adhesive layer 20a is formed, the adhesive layer 20a is deformed over time and enters a plurality of concave portions. It is suppressed. The entire disclosure of International Publication No. 2021/167091 is incorporated herein by reference.

The polymer contained in the adhesive composition is, for example, a copolymer, and includes at least one (meth)acrylate monomer (for example, an alkyl (meth)acrylate), a hydroxyl group-containing copolymerizable monomer, and a carboxyl group-containing copolymerizable monomer. and a copolymer of at least one copolymerizable functional group-containing monomer selected from the group consisting of nitrogen-containing vinyl monomers. When at least one copolymerizable functional group-containing monomer includes a nitrogen-containing vinyl monomer, the mass ratio of the (meth)acrylate monomer and the nitrogen-containing vinyl monomer is, for example, between 95:5 and 50:50, 95:5 to 55. :45, between 95:5 and 60:40, between 90:10 and 50:50, between 90:10 and 55:45, between 90:10 and 60:40, between 85:15 and 50:50, 85 :15 to 55:45, 85:15 to 60:40, 80:20 to 50:50, 80:20 to 55:45, 80:20 to 60:40, 75:25 to 50: 50, 75:25 to 55:45, or 75:25 to 60:40, preferably 90:10 to 60:40.

The adhesive layer Ab is formed by curing the curable resin of an adhesive composition containing a polymer and a curable resin. First, an adhesive composition layer formed of an adhesive composition is provided on the first main surface 12s of the optical sheet 10a. Subsequently, with the adhesive composition layer provided on the first main surface 12s of the optical sheet 10a, the curable resin of the adhesive composition is cured by applying heat or irradiating active energy rays to the adhesive composition layer. The curable resin (for example, ultraviolet curable resin) preferably has a mass average molecular weight of, for example, 4000 or more from the viewpoint of suppressing the adhesive composition layer from entering the plurality of recesses.

For example, the initial tensile modulus of elasticity at 23°C before curing the curable resin of the adhesive composition is, for example, 0.35 MPa or more, 0.40 MPa or more, 0.45 MPa or more, or 0.50 MPa or more, and is also 8.00 MPa or less and 7.70 MPa. Hereinafter, it is 7.50 MPa or less, 7.00 MPa or less, 6.50 MPa or less, 6.00 MPa or less, 5.50 MPa or less, 5.00 MPa or less, 4.50 MPa or less, 4.00 MPa or less, 3.50 MPa or less, or 3.00 MPa or less. The initial tensile modulus at 23°C after curing the curable resin of the adhesive composition is, for example, 1.00 MPa or more, 1.50 MPa or more, 2.00 MPa or more, 2.50 MPa or more, 3.00 MPa or more, 3.50 MPa or more, 4.00 MPa or more, It is more than 4.50MPa or more than 5.00MPa. The upper limit of the initial tensile modulus at 23°C after curing the curable resin of the adhesive composition is not particularly limited, but is, for example, 1000 MPa or less, 800 MPa or less, 600 MPa or less, 400 MPa or less, or 200 MPa or less. It is more preferable that the initial tensile modulus of elasticity at 23°C before curing the curable resin of the adhesive composition is 0.40 MPa or more and 7.70 MPa or less, and that the initial tensile modulus of elasticity at 23°C after curing the curable resin of the adhesive composition is 3.00 MPa or more. do.

The gel fraction before curing the curable resin of the adhesive composition is, for example, 75% or more, and the gel fraction after curing the curable resin of the adhesive composition is, for example, 90% or more. The upper limit of these gel fractions is not particularly limited, but is, for example, 100%.

(3) Adhesive layer Ac

International application PCT/JP2022/004554 by the present applicant includes a polyester resin that is a copolymer of a polyhydric carboxylic acid and a polyhydric alcohol, a crosslinking agent, and at least one compound selected from the group consisting of an organozirconium compound, an organoiron compound, and an organoaluminum compound. An adhesive that is formed by crosslinking an adhesive composition containing a crosslinking catalyst, has a gel fraction of 40% or more after being maintained for 300 hours at a temperature of 85°C and a relative humidity of 85%, and has a 180° peel adhesive force to a PMMA film of 100mN/20mm or more. The layer (hereinafter sometimes referred to as “adhesive layer Ac”) is described. The adhesive layer Ac can also suppress changes over time under high temperature and high humidity. The entire disclosure of international application PCT/JP2022/004554 is incorporated herein by reference.

The following adhesives can be preferably used as the adhesive forming the adhesive layer Aa or adhesive layer Ab.

The adhesive contains, for example, a (meth)acrylic polymer, and the (meth)acrylic polymer is, for example, a copolymer of a nitrogen-containing (meth)acrylic monomer and at least one type of other monomer. The nitrogen-containing (meth)acrylic monomer has, for example, a nitrogen-containing cyclic structure. When a (meth)acrylic polymer is prepared using a nitrogen-containing (meth)acrylic monomer, especially when the nitrogen-containing (meth)acrylic monomer has a nitrogen-containing cyclic structure, the effect of improving the elastic properties of the (meth)acrylic polymer is obtained. Lose.

When the adhesive contains a (meth)acrylic polymer, it is preferable that the (meth)acrylic polymer is crosslinked. In addition, when the adhesive contains a (meth)acrylic polymer, the adhesive may further include an active energy ray-curable resin (for example, an ultraviolet curable resin) and a curing agent (for example, a photopolymerization initiator), or A cured product of a pre-curable resin may be additionally included. Active energy rays are, for example, visible light and ultraviolet rays. By introducing a crosslinked structure into the adhesive, deformation upon attachment of the adhesive and deformation over time are suppressed. In particular, by curing the active energy ray curable resin after providing an adhesive composition layer (which becomes the adhesive layer 20a) on the optical sheet 10a, deformation of the adhesive layer 20a over time can be suppressed, and the adhesive layer 20a ) can suppress changes over time in the degree of intrusion into the concave portion. Additionally, when the active energy ray curable resin is cured, the adhesive layer 20a becomes hard. If the adhesive layer 20a is too hard, it may become difficult to bond the adhesive layer 20a to the optical sheet 10a by a roll-to-roll method. However, after applying the adhesive composition layer to the optical sheet 10a, the active energy ray This problem can be avoided by curing the curable resin.

The adhesive layer 20a containing a cured product of an active energy ray-curable resin is formed, for example, by the following method. First, an adhesive composition solution layer is formed with an adhesive composition solution containing a (meth)acrylic polymer, a crosslinking agent, an active energy ray curable resin, a polymerization initiator, and a solvent. The adhesive composition solution layer is formed, for example, on the main surface of the substrate that has undergone peeling treatment. Next, the solvent in the adhesive composition solution layer is removed, and the (meth)acrylic polymer in the adhesive composition solution layer is crosslinked with a crosslinking agent (for example, by heating), thereby obtaining an adhesive composition layer having a crosslinked structure. When the adhesive composition solution layer is formed on the peeling-treated main surface of the base material, the adhesive composition layer is formed on the peeling-treated main surface of the base material, and a laminate having the base material and the adhesive composition layer is obtained. Here, the crosslinked structure formed by a (meth)acrylic polymer and a crosslinking agent is referred to as the first crosslinked structure. It is distinguished from a crosslinked structure (second crosslinked structure) formed by curing an active energy ray curable resin, which will be described later. In the step of removing the solvent of the adhesive composition solution layer, the polymer of the adhesive composition solution layer may be crosslinked, and after the step of removing the solvent of the adhesive composition solution layer, separately from the step of removing the solvent of the adhesive composition solution layer, the adhesive A step of crosslinking the polymer in the composition solution layer may be additionally performed. Thereafter, the adhesive composition layer is attached on the first main surface 12s of the optical sheet 10a, and the adhesive composition layer is disposed on the first main surface 12s of the optical sheet 10a. By irradiating an active energy ray to harden the active energy ray-curable resin, the adhesive layer 20a having a second cross-linked structure in addition to the first cross-linked structure can be formed. It is thought that the first cross-linked structure and the second cross-linked structure of the adhesive layer 20a form a so-called interpenetrating network structure (IPN).

The adhesive layer 20a containing no cured product of the active energy ray-curable resin is formed, for example, by the following method. First, an adhesive composition solution layer is formed with an adhesive composition solution containing a polymer, a crosslinking agent, and a solvent. This adhesive composition solution does not contain an active energy ray curable resin or a polymerization initiator. The adhesive composition solution layer is formed, for example, on the main surface of the substrate that has undergone peeling treatment. Next, the solvent in the adhesive composition solution layer is removed, and the polymer in the adhesive composition solution layer is crosslinked with a crosslinking agent (for example, by heating), thereby obtaining an adhesive layer 20a having a crosslinked structure. When the adhesive composition solution layer is formed on the peeling-treated main surface of the base material, an adhesive layer is formed on the peeling-treated main surface of the base material, and a laminate having the base material and the adhesive layer is obtained. In the step of removing the solvent of the adhesive composition solution layer, the polymer of the adhesive composition solution layer may be crosslinked, and after the step of removing the solvent of the adhesive composition solution layer, separately from the step of removing the solvent of the adhesive composition solution layer, the adhesive A step of crosslinking the polymer in the composition solution layer may be additionally performed.

The adhesive preferably does not contain a graft polymer. When formed from an adhesive composition containing a graft polymer, such as the adhesive layer described in Patent Document 1, the design factors and control factors of the material increase, and mass productivity may be inferior. Adhesives that do not contain a graft polymer can have creep characteristics adjusted according to various factors (e.g., type and amount of cross-linking agent, type and amount of actinic ray curable resin).

Preferred specific examples of the adhesive are described below.

Adhesives include, for example, (meth)acrylic polymers. As the monomer used for producing the (meth)acrylic polymer, any (meth)acrylate can be used, and there is no particular limitation. For example, an alkyl (meth)acrylate having an alkyl group having 4 or more carbon atoms can be used. In this case, the ratio of the alkyl (meth)acrylate having an alkyl group with 4 or more carbon atoms to the total amount of monomers used for producing the (meth)acrylic polymer is, for example, 50% by mass or more.

In this specification, “alkyl (meth)acrylate” refers to (meth)acrylate having a linear or branched alkyl group. The alkyl group of the alkyl (meth)acrylate preferably has 4 or more carbon atoms, more preferably 4 or more and 9 or less. Additionally, (meth)acrylate refers to acrylate and/or methacrylate.

Specific examples of alkyl (meth)acrylate include n-butyl (meth)acrylate, s-butyl (meth)acrylate, t-butyl (meth)acrylate, isobutyl (meth)acrylate, and n-pentyl (meth)acrylate. ) Acrylate, isopentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, isoamyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-octyl (meth) Acrylate, isooctyl (meth)acrylate, n-nonyl (meth)acrylate, isononyl (meth)acrylate, n-decyl (meth)acrylate, isodecyl (meth)acrylate, n-dodecyl ( Meta)acrylate, isomyristyl (meth)acrylate, n-tridecyl (meth)acrylate, n-tetradecyl (meth)acrylate, stearyl (meth)acrylate, isostearyl (meth)acrylate etc. can be mentioned. These can be used alone or in combination.

The adhesive may contain a (meth)acrylic polymer that is a copolymer of a nitrogen-containing (meth)acrylic monomer and at least one type of other monomer. In this case, the (meth)acrylic polymer is preferably a copolymer copolymerized using the following monomers in the following amounts, assuming that the total amount of monomers used in the copolymerization is 100 parts by mass.

Nitrogen-containing (meth)acrylic monomer: 10.0 parts by mass or more, 15.0 parts by mass or more, 20.0 parts by mass or more, 25.0 parts by mass or more, 30.0 parts by mass or more, or 35.0 parts by mass or more, and also 40.0 parts by mass or less, 35.0 parts by mass or less, 30.0 parts by mass or less, 25.0 parts by mass or less, 20.0 parts by mass or less, or 15.0 parts by mass or less. For example, 10.0 parts by mass or more and 40.0 parts by mass or less.

Acrylic monomer containing hydroxyl group: 0.05 parts by mass or more, 0.75 parts by mass or more, 1.0 parts by mass or more, 2.0 parts by mass or more, 3.0 parts by mass or more, 4.0 parts by mass or more, 5.0 parts by mass or more, 6.0 parts by mass or more, 7.0 parts by mass or more or more, 8.0 parts by mass or more, or 9.0 parts by mass or more, and also 10.0 parts by mass or less, 9.0 parts by mass or less, 8.0 parts by mass or less, 7.0 parts by mass or less, 6.0 parts by mass or less, 5.0 parts by mass or less, 4.0 parts by mass or less, 3.0 parts by mass or less. Part by mass or less, 2.0 parts by mass or less, or 1.0 parts by mass or less. For example, 0.05 parts by mass or more and 10.0 parts by mass or less.

Carboxyl group-containing acrylic monomer: 1.0 parts by mass or more, 2.0 parts by mass or more, 3.0 parts by mass or more, 4.0 parts by mass or more, 5.0 parts by mass or more, 6.0 parts by mass or more, 7.0 parts by mass or more, 8.0 parts by mass or more, or 9.0 parts by mass or more. , also 10.0 parts by mass or less, 9.0 parts by mass or less, 8.0 parts by mass or less, 7.0 parts by mass or less, 6.0 parts by mass or less, 5.0 parts by mass or less, 4.0 parts by mass or less, 3.0 parts by mass or less, or 2.0 parts by mass or less. For example, 1.0 parts by mass or more and 10.0 parts by mass or less.

Alkyl (meth)acrylate monomer: (100 parts by mass) - (total amount of monomers other than alkyl (meth)acrylate monomer used in copolymerization)

In this specification, “nitrogen-containing (meth)acrylic monomer” includes, without particular limitation, monomers that have a polymerizable functional group having an unsaturated double bond of a (meth)acryloyl group and also have a nitrogen atom. “Nitrogen-containing (meth)acrylic monomer” has, for example, a nitrogen-containing cyclic structure. Examples of nitrogen-containing (meth)acrylic monomers having a nitrogen-containing cyclic structure include, for example, N-vinyl-2-pyrrolidone (NVP), N-vinyl-ε-caprolactam (NVC), and 4-acryloyl. Examples include morpholine (ACMO). These can be used alone or in combination.

In this specification, “hydroxyl group-containing acrylic monomer” includes, without particular limitation, monomers that have a polymerizable functional group having an unsaturated double bond of a (meth)acryloyl group and also have a hydroxyl group. For example, 2-hydroxybutyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6- Hydroxyalkyl (meth)acrylate, such as hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, and 12-hydroxylauryl (meth)acrylate. acrylate; 4-hydroxymethylcyclohexyl (meth)acrylate, 4-hydroxybutyl vinyl ether, etc.

In this specification, “carboxyl group-containing acrylic monomer” includes, without particular limitation, monomers that have a polymerizable functional group having an unsaturated double bond such as a (meth)acryloyl group or a vinyl group, and also have a carboxyl group. Examples of unsaturated carboxylic acid-containing monomers include (meth)acrylic acid, carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, itaconic acid, maleic acid, fumaric acid, and crotonic acid. These can be used alone or in combination.

The adhesive may contain a (meth)acrylic polymer that is a copolymer of a carboxyl group-containing acrylic monomer and at least one other monomer (however, nitrogen-containing (meth)acrylic monomer is excluded). In this case, the (meth)acrylic polymer is preferably a copolymer copolymerized using the following monomers in the following amounts when the total amount of monomers used in the copolymerization is 100 parts by mass.

Carboxyl group-containing acrylic monomer: 1.0 parts by mass or more, 2.0 parts by mass or more, 3.0 parts by mass or more, 4.0 parts by mass or more, 5.0 parts by mass or more, 6.0 parts by mass or more, 7.0 parts by mass or more, 8.0 parts by mass or more, or 9.0 parts by mass or more. , also 10.0 parts by mass or less, 9.0 parts by mass or less, 8.0 parts by mass or less, 7.0 parts by mass or less, 6.0 parts by mass or less, 5.0 parts by mass or less, 4.0 parts by mass or less, 3.0 parts by mass or less, or 2.0 parts by mass or less. For example, 1.0 parts by mass or more and 10.0 parts by mass or less.

Alkyl (meth)acrylate monomer: 90.0 parts by mass or more, 91.0 parts by mass or more, 92.0 parts by mass or more, 93.0 parts by mass or more, 94.0 parts by mass or more, 95.0 parts by mass or more, 96.0 parts by mass or more, 97.0 parts by mass or more, or 98.0 parts by mass. parts or more, 99.0 parts by mass or less, 98.0 parts by mass or less, 97.0 parts by mass or less, 96.0 parts by mass or less, 95.0 parts by mass or less, 94.0 parts by mass or less, 93.0 parts by mass or less, 92.0 parts by mass or less, or 91.0 parts by mass or less. For example, 90.0 parts by mass or more and 99.0 parts by mass or less.

Crosslinking agents for introducing a crosslinking structure into a (meth)acrylic polymer include isocyanate-based crosslinking agents, epoxy-based crosslinking agents, silicone-based crosslinking agents, oxazoline-based crosslinking agents, aziridine-based crosslinking agents, silane-based crosslinking agents, alkyl etherified melamine-based crosslinking agents, and metal chelate-based crosslinking agents. Crosslinking agents such as peroxide are included. Crosslinking agents can be used singly or in combination of two or more.

An isocyanate-based crosslinking agent refers to a compound having two or more isocyanate groups (including isocyanate regenerative functional groups temporarily protected by blocking agents or quantization, etc.) in one molecule.

Examples of the isocyanate-based crosslinking agent include aromatic isocyanates such as tolylene diisocyanate and xylene diisocyanate, alicyclic isocyanates such as isophorone diisocyanate, and aliphatic isocyanates such as hexamethylene diisocyanate.

More specifically, for example, lower aliphatic polyisocyanates such as butylene diisocyanate and hexamethylene diisocyanate, alicyclic isocyanates such as cyclopentylene diisocyanate, cyclohexylene diisocyanate, and isophorone diisocyanate, 2,4- Aromatic diisocyanates such as tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, xylylene diisocyanate, polymethylene polyphenylisocyanate, trimethylol propane/tolylene diisocyanate trimer adduct (manufactured by Tosoh Corporation) , brand name Coronate L), trimethylolpropane/hexamethylene diisocyanate trimer adduct (manufactured by Tosoh Corporation, brand name Coronate HL), isocyanurate form of hexamethylene diisocyanate (manufactured by Tosoh Corporation, Isocyanate adducts such as Coronate HX), trimethylolpropane adducts of xylylene diisocyanate (manufactured by Mitsui Chemicals Co., Ltd., product name D110N), and trimethylolpropane adducts of hexamethylene diisocyanate (Mitsui Chemicals Co., Ltd.) Co., Ltd. product name D160N); Examples include polyether polyisocyanate, polyester polyisocyanate, adducts thereof with various polyols, and polyisocyanates polyfunctionalized with isocyanurate linkages, biuret linkages, allophanate linkages, etc.

Isocyanate-based crosslinking agents may be used individually, or two or more types may be mixed. The blending amount of the isocyanate-based crosslinking agent is, for example, 0.01 parts by mass or more, 0.02 parts by mass or more, 0.05 parts by mass or more, or 0.1 parts by mass or more, with respect to 100 parts by mass of the (meth)acrylic polymer, and also 10 parts by mass or less and 9 parts by mass or less. Hereinafter, it is 8 parts by mass or less, 7 parts by mass or less, 6 parts by mass or less, or 5 parts by mass or less, preferably 0.01 parts by mass or more and 10 parts by mass or less, 0.02 parts by mass or more and 9 parts by mass or less, and 0.05 parts by mass or more. It is below wealth. The mixing amount may be appropriately adjusted in consideration of cohesion, prevention of peeling in durability tests, etc.

In addition, in the aqueous dispersion of a modified (meth)acrylic polymer produced by emulsion polymerization, it is not necessary to use an isocyanate-based crosslinking agent, but if necessary, a blocked isocyanate-based crosslinking agent can be used because it easily reacts with water.

An epoxy-based crosslinking agent is a polyfunctional epoxy compound having two or more epoxy groups per molecule. As an epoxy-based crosslinking agent, for example, bisphenol A, epichlorhydrin type epoxy resin, ethylene glycidyl ether, N,N,N',N'-tetraglycidyl-m-xylenediamine, diglycy. Diylaniline, diamineglycidylamine, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, 1,6-hexanediol diglycidyl ether, neopentyl glycol diglycidyl ether, Ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, sorbitol polyglycidyl ether, glycerol polyglycidyl ether, pentaerythritol poly. Glycidyl ether, glycerin diglycidyl ether, glycerin triglycidyl ether, polyglycerol polyglycidyl ether, sorbitan polyglycidyl ether, trimethylol propane polyglycidyl ether, diglycidyl adipic acid. In addition to esters, o-phthalic acid diglycidyl ester, triglycidyl-tris(2-hydroxyethyl)isocyanurate, resorcinol diglycidyl ether, and bisphenol-S-diglycidyl ether, there is an epoxy group in the molecule. An epoxy resin having two or more of these can be mentioned. As an epoxy-based crosslinking agent, for example, products manufactured by Mitsubishi Gas Chemical Co., Ltd., brand names “Tetrad C” and “Tetrad X” can be used.

Epoxy-based crosslinking agents may be used individually, or two or more types may be mixed. The blending amount of the epoxy-based crosslinking agent is, for example, 0.01 parts by mass or more, 0.02 parts by mass or more, 0.05 parts by mass or more, or 0.1 parts by mass or more, and 10 parts by mass or less, 9 parts by mass or less, with respect to 100 parts by mass of the (meth)acrylic polymer. Hereinafter, it is 8 parts by mass or less, 7 parts by mass or less, 6 parts by mass or less, or 5 parts by mass or less, preferably 0.01 parts by mass or more and 10 parts by mass or less, 0.02 parts by mass or more and 9 parts by mass or less, and 0.05 parts by mass or more. It is below wealth. The mixing amount may be appropriately adjusted in consideration of cohesion, prevention of peeling in durability tests, etc.

As a crosslinking agent for peroxide, any one that generates radical active species through heating and promotes crosslinking of the base polymer of the adhesive can be appropriately used. However, in consideration of workability and stability, peroxides with a half-life temperature of 80°C or more and 160°C or less per minute are recommended. It is preferable to use, and it is more preferable to use a peroxide whose temperature is 90°C or higher and 140°C or lower.

Examples of peroxides include di(2-ethylhexyl)peroxydicarbonate (1-minute half-life temperature: 90.6°C), di(4-t-butylcyclohexyl)peroxydicarbonate (1-minute half-life temperature: 92.1°C), di -sec-butylperoxydicarbonate (half-life temperature for 1 minute: 92.4°C), t-butylperoxyneodecanoate (half-life temperature for 1 minute: 103.5°C), t-hexylperoxypivalate (half-life temperature for 1 minute: 109.1 ℃), t-butylperoxypivalate (1 minute half-life temperature: 110.3 ℃), dilauroyl peroxide (1 minute half-life temperature: 116.4 ℃), di-n-octanoyl peroxide (1 minute half-life temperature: 117.4 ℃), 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate (1 minute half-life temperature: 124.3 ℃), di(4-methylbenzoyl) peroxide (1 minute half-life temperature: 128.2 ℃) ), dibenzoyl peroxide (1 minute half-life temperature: 130.0°C), t-butylperoxyisobutyrate (1 minute half-life temperature: 136.1°C), 1,1-di(t-hexylperoxy)cyclohexane (1 minute) Half-life temperature: 149.2°C), etc. Among them, in terms of particularly excellent crosslinking reaction efficiency, di(4-t-butylcyclohexyl)peroxydicarbonate (half-life temperature for 1 minute: 92.1°C), dilauroyl peroxide (half-life temperature for 1 minute: 116.4°C), Benzoyl peroxide (1 minute half-life temperature: 130.0°C) is preferably used.

In addition, the half-life of peroxide is an indicator of the decomposition rate of peroxide and refers to the time until the remaining amount of peroxide is halved. The decomposition temperature for obtaining the half-life at an arbitrary time and the half-life time at an arbitrary temperature are described in the manufacturer's catalog, etc., for example, Nichiyu Corporation's "Organic Peroxide Catalog 9th Edition (May 2003) )”, etc.

One type of peroxide may be used individually, or two or more types may be mixed and used. The amount of peroxide to be added is preferably 0.02 parts by mass or more and 2 parts by mass or less, and preferably 0.05 parts by mass or more and 1 part by mass or less, per 100 parts by mass of the (meth)acrylic polymer. In order to adjust processability, reworkability, crosslinking stability, peelability, etc., it is appropriately adjusted within this range.

Additionally, as a method for measuring the amount of decomposed peroxide remaining after the reaction treatment, for example, it can be measured by HPLC (high-performance liquid chromatography).

More specifically, for example, about 0.2 g of the adhesive after the reaction treatment is taken out, immersed in 10 ml of ethyl acetate, shaken and extracted with a shaker at 25°C and 120 rpm for 3 hours, and then left to stand at room temperature for 3 days. Next, 10 ml of acetonitrile was added, shaken at 120 rpm at 25°C for 30 minutes, and filtered through a membrane filter (0.45 μm). About 10 μl of the obtained extract was injected into HPLC for analysis, and was used as the amount of peroxide after reaction treatment. .

Additionally, as a crosslinking agent, an organic crosslinking agent or a multifunctional metal chelate may be used in combination. A polyfunctional metal chelate is one in which a multivalent metal is covalently bonded or coordinated with an organic compound. Examples of polyvalent metal atoms include Al, Cr, Zr, Co, Cu, Fe, Ni, V, Zn, In, Ca, Mg, Mn, Y, Ce, Sr, Ba, Mo, La, Sn, and Ti. . Examples of the atom in the organic compound that is covalently bonded or coordinated include an oxygen atom, and examples of the organic compound include alkyl esters, alcohol compounds, carboxylic acid compounds, ether compounds, and ketone compounds.

The mixing amount of the active energy ray-curable resin is, for example, 3 parts by mass or more and 60 parts by mass or less with respect to 100 parts by mass of the (meth)acrylic polymer. The mass average molecular weight (Mw) before curing is 4,000 or more and 50,000 or less. As the active energy ray-curable resin, for example, acrylate-based, epoxy-based, urethane-based, or ene-thiol-based ultraviolet curable resin can be preferably used.

As the active energy ray-curable resin, monomers and/or oligomers that undergo radical polymerization or cationic polymerization by active energy rays are used.

Monomers that undergo radical polymerization by active energy rays include monomers having unsaturated double bonds such as (meth)acryloyl groups and vinyl groups, and monomers having (meth)acryloyl groups are particularly preferred due to their excellent reactivity. It is used.

Specific examples of monomers having a (meth)acryloyl group include allyl (meth)acrylate, caprolactone (meth)acrylate, cyclohexyl (meth)acrylate, N, N-diethylaminoethyl (meth) Acrylate, 2-ethylhexyl (meth)acrylate, heptadecafluorodecyl (meth)acrylate, glycidyl (meth)acrylate, caprolactone modified 2-hydroxylethyl (meth)acrylate, isobornyl (meth)acrylate, morpholine (meth)acrylate, phenoxyethyl (meth)acrylate, tripropylene glycol di(meth)acrylate, bisphenol A diglycidyl ether di(meth)acrylate, hydroxyp Varnish neopentyl glycol di(meth)acrylate, Trimethylol propane tri(meth)acrylate, Trimethylol propane ethoxy tri(meth)acrylate, Pentaerythritol tri(meth)acrylate, Pentaerythritol tetra(meth) Acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, caprolactone modified dipentaerythritol hexa(meth)acrylate, etc. are mentioned.

Oligomers that undergo radical polymerization by active energy rays include polyesters (polyesters) in which two or more unsaturated double bonds such as (meth)acryloyl group or vinyl group are added to the skeleton of polyester, epoxy, urethane, etc. as functional groups similar to monomers. Meta)acrylate, epoxy (meth)acrylate, urethane (meth)acrylate, etc. are used.

Polyester (meth)acrylate is obtained by reacting (meth)acrylic acid with polyester of terminal hydroxyl groups obtained from polyhydric alcohol and polyhydric carboxylic acid. Specific examples include Aronix M-6000, 7000 manufactured by Toagosei Co., Ltd. Examples include the 8000 and 9000 series.

Epoxy (meth)acrylate is obtained by reacting (meth)acrylic acid with an epoxy resin. Specific examples include Lipoxy SP and VR series manufactured by Showa Kobun City Co., Ltd. and epoxy ester manufactured by Kyoeisha Chemical Co., Ltd. series, etc.

Urethane (meth)acrylate is obtained by reacting polyol, isocyanate, and hydroxy (meth)acrylate, and specific examples include Art Resin UN series manufactured by Negami Kogyo Co., Ltd. and NK manufactured by Shinnakamura Kagaku Kogyo Co., Ltd. Examples include the Oligo U series and the Seiko UV series manufactured by Mitsubishi Chemical Corporation.

The photopolymerization initiator has the effect of generating radicals by exciting and activating them by irradiating ultraviolet rays and curing the polyfunctional oligomer by radical polymerization. For example, 4-phenoxydichloroacetophenone, 4-t-butyldichloroacetophenone, diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-(4-iso Propylphenyl)-2-hydroxy-2-methylpropan-1-one, 1-(4-dodecylphenyl)-2-hydroxy-2-methylpropan-1-one, 4-(2-hydroxy Toxy)phenyl (2-hydroxy-2-propyl) ketone, 1-hydroxycyclohexylphenyl ketone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropane-1, etc. Acetophenone-based photopolymerization initiators, benzoin-based photopolymerization initiators such as benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, and 2,2-dimethoxy-2-phenylacetophenone, Benzos such as benzophenone, benzoylbenzoic acid, methyl benzoylbenzoate, 4-phenylbenzophenone, hydroxybenzophenone, 4-benzoyl-4'-methyldiphenyl sulfide, 3,3'-dimethyl-4-methoxybenzophenone, etc. Phenone-based photopolymerization initiator, thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, 2,4-dichlorothioxanthone, 2,4 -Thioxanthone-based photopolymerization initiators such as diethylthioxanthone and 2,4-diisopropylthioxanthone, α-acyloxime ester, acylphosphine oxide, methylphenylglyoxylate, benzyl, camphor quinone, and dibenzoate. Special photopolymerization initiators such as berone, 2-ethylanthraquinone, and 4',4"-diethylisophthalophenone can be used. Additionally, as photopolymerization initiators, allylsulfonium hexafluorophosphate salt and sulfonium hexafluorophosphate are used. Photocationic polymerization initiators such as phosphate salts and bis(alkylphenyl)iodonium hexafluorophosphate can also be used.

Regarding the photopolymerization initiator, it is also possible to use two or more types together. The polymerization initiator is preferably blended in a range of usually 0.5 to 30 parts by mass, and more preferably 1 to 20 parts by mass, with respect to 100 parts by mass of the active energy ray-curable resin. If it is less than 0.5 parts by mass, polymerization does not proceed sufficiently and the curing speed becomes slow, and if it exceeds 30 parts by mass, the hardness of the cured sheet may decrease.

Active energy rays are not particularly limited, but are preferably ultraviolet rays, visible rays, and electron rays. Crosslinking treatment by ultraviolet irradiation can be performed using an appropriate ultraviolet source such as a high-pressure mercury lamp, low-pressure mercury lamp, excimer laser, metal halide lamp, or LED lamp. At that time, the irradiation amount of ultraviolet rays can be appropriately selected depending on the degree of crosslinking required, but it is usually preferable to select within the range of 0.2 J/cm2 to 10 J/cm2 for ultraviolet rays. The temperature during irradiation is not particularly limited, but is preferably up to about 140°C considering the heat resistance of the support.

When the adhesive contains a polyester-based polymer instead of or together with the (meth)acrylic-based polymer, for example, a polyester-based polymer having the following characteristics is preferred.

Type of carboxylic acid component (or skeletal characteristics, etc.): Contains dicarboxylic acid containing at least two carboxyl groups, specifically dicarboxylic acid. The dicarboxylic acid is not particularly limited, but examples include dimer acids derived from sebacic acid, oleic acid, and erucic acid. Other examples include glutaric acid, suberic acid, adipic acid, azelaic acid, 1,4-cyclohexanedicarboxylic acid, 4-methyl-1,2-cyclohexanedicarboxylic acid, dodecenyl succinic anhydride, Aliphatic or cycloaliphatic dicarboxylic acids such as fumaric acid, succinic acid, dodecane diacid, hexahydrophthalic anhydride, tetrahydrophthalic anhydride, maleic acid, maleic anhydride, itaconic acid, citraconic acid, terephthalic acid, isophthalic acid, ortho Phthalic acid, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 4,4'-diphenyldicarboxylic acid, 2,2'-diphenyldicarboxylic acid, 4,4' -Diphenyl ether dicarboxylic acid can be mentioned. In addition to the above dicarboxylic acids, tricarboxylic acids containing three or more carboxyl groups can also be used.

Type of diol component (or skeletal characteristics, etc.): Diol containing at least two hydroxyl groups in the molecule, specifically diol. Dimeric diols derived from fatty acid esters, oleic acid, erucic acid, etc., glycerol monostearate, etc. Other examples include aliphatic glycols such as ethylene glycol and 1,2-propylene glycol, and other than aliphatic glycols, include ethylene oxide adducts and propylene oxide adducts of bisphenol A, and ethylene oxide adducts and propylene oxide adducts of hydrogenated bisphenol A. etc. can be mentioned.

As a crosslinking agent for introducing a crosslinking structure into the polyester polymer, an isocyanate-based crosslinking agent, an oxazoline-based crosslinking agent, an aziridine-based crosslinking agent, a silane-based crosslinking agent, an alkyl etherified melamine-based crosslinking agent, and a metal chelate-based crosslinking agent can be used. The compounding quantity is, for example, 2.0 parts by mass or more and 10.0 parts by mass or less with respect to 100 parts by mass of the polyester polymer.

Specific examples of the composition of the adhesive layer Ac are described below.

<Polyvalent carboxylic acid>

As polyhydric carboxylic acid, for example,

Aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, benzylmalonic acid, diphenic acid, 4,4'-oxydibenzoic acid, and naphthalenedicarboxylic acid;

Malonic acid, dimethylmalonic acid, succinic acid, glutaric acid, adipic acid, trimethyladipic acid, pimelic acid, 2,2-dimethylglutaric acid, azelaic acid, sebacic acid, fumaric acid, maleic acid, itaconic acid, thiodidine. Aliphatic dicarboxylic acids such as propionic acid and diglycolic acid;

1,3-cyclopentanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 1,3-cyclopentanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 2,5-norbor Alicyclic dicarboxylic acids such as nadicarboxylic acid and adamantane dicarboxylic acid;

etc. can be mentioned. These can be used individually or in combination of two or more types.

Among these, from the viewpoint of providing cohesive force, those containing aromatic dicarboxylic acids are preferable, and those containing terephthalic acid or isophthalic acid are particularly preferable.

<Polyvalent alcohol>

As polyhydric alcohols, for example,

Ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, 1,3-propanediol, 2,4-dimethyl-2-ethylhexane-1,3-diol, 2-methyl-1,3- Propanediol, 2,2-dimethyl-1,3-propanediol (neopentyl glycol), 2-ethyl-2-butyl-1,3-propanediol, 2-ethyl-2-isobutyl-1,3-propane Diol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 2,2,4-trimethyl-1,6 -Aliphatic diols such as hexanediol and polytetramethylene glycol;

1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, spiroglycol, tricyclodecanedimethanol, adamantanediol, 2,2,4,4-tetra Alicyclic diols such as methyl-1,3-cyclobutanediol;

4,4'-thiodiphenol, 4,4'-methylenediphenol, 4,4'-dihydroxybiphenyl, o-, m- and p-dihydroxybenzene, 2,5-naphthalenediol, p -Aromatic diols such as xylenediol and their ethylene oxide and propylene oxide adducts;

etc. can be mentioned. These can be used individually or in combination of two or more types.

Among these, those containing aliphatic diol or alicyclic diol are preferable, and those containing polytetramethylene glycol, neopentyl glycol, or cyclohexanedimethanol are more preferable.

<Cross-linking agent>

The crosslinking agent is not particularly limited and known ones can be used, for example, polyisocyanurate, polyfunctional isocyanate, polyfunctional melamine compound, polyfunctional epoxy compound, polyfunctional oxazoline compound, polyfunctional aziridine compound. , metal chelate compounds, etc. can be used. In particular, it is preferable to use an isocyanate-based crosslinking agent from the viewpoint of obtaining transparency of the resulting adhesive layer and an elastic modulus suitable for the adhesive layer.

An isocyanate-based crosslinking agent refers to a compound having two or more isocyanate groups (including isocyanate regenerative functional groups temporarily protected by blocking agents or quantization, etc.) in one molecule.

Examples of the isocyanate-based crosslinking agent include aromatic isocyanates such as tolylene diisocyanate and xylene diisocyanate, alicyclic isocyanates such as isophorone diisocyanate, and aliphatic isocyanates such as hexamethylene diisocyanate.

More specifically, for example, lower aliphatic polyisocyanates such as butylene diisocyanate and hexamethylene diisocyanate, alicyclic isocyanates such as cyclopentylene diisocyanate, cyclohexylene diisocyanate, and isophorone diisocyanate, 2,4- Aromatic diisocyanates such as tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, xylylene diisocyanate, polymethylene polyphenylisocyanate, trimethylol propane/tolylene diisocyanate trimer adduct (manufactured by Tosoh Corporation) , brand name Coronate L), trimethylolpropane/hexamethylene diisocyanate trimer adduct (manufactured by Tosoh Corporation, brand name Coronate HL), isocyanurate form of hexamethylene diisocyanate (manufactured by Tosoh Corporation, Isocyanate adducts such as Coronate HX), trimethylolpropane adducts of xylylene diisocyanate (manufactured by Mitsui Chemicals Co., Ltd., product name D110N), and trimethylolpropane adducts of hexamethylene diisocyanate (Mitsui Chemicals Co., Ltd.) Co., Ltd. product name D160N); Examples include polyether polyisocyanate, polyester polyisocyanate, adducts thereof with various polyols, and polyisocyanates polyfunctionalized with isocyanurate linkages, biuret linkages, allophanate linkages, etc. Using an aliphatic isocyanate is more preferable because an adhesive layer with a high gel fraction can be obtained with a small amount of crosslinking agent.

Isocyanate-based crosslinking agents may be used individually, or two or more types may be mixed. The lower limit of the amount of the isocyanate-based crosslinking agent is 6 parts by mass or more, preferably 7 parts by mass or more, 8 parts by mass, 9 parts by mass, or 10 parts by mass or more, based on 100 parts by mass of the polyester resin. The upper limit of the mixing amount is 20 parts by mass or less, and preferably 15 parts by mass or less. By setting it within this range, it is possible to prevent the adhesive layer from invading the recesses of the uneven structure over time while maintaining good adhesion to the surface having the uneven structure.

<Cross-linking catalyst>

Examples of the organic aluminum compound include aluminum trisacetylacetonate, aluminum trisethylacetoacetate, and diisopropoxyaluminum ethylacetoacetate.

Examples of organic iron compounds include acetylacetone-iron complex.

Examples of the organic zirconium compound include zirconium tetraacetylacetonate.

These are used individually or in combination of two or more types as needed.

By using a cross-linking catalyst, the cross-linking speed can be increased and the production lead time can be shortened.

As a method of forming the adhesive layer Ac, a known method can be adopted. For example, the following method can be mentioned. First, an adhesive composition layer is formed by applying (applying) an adhesive composition (or a solution containing the adhesive composition) onto a support (base material) and drying it as necessary. Typically, an adhesive composition solution layer containing a polyester resin, a crosslinking agent, a crosslinking catalyst, and a solvent is applied to the substrate to form an adhesive composition solution layer on the substrate, and the solvent in the adhesive composition solution layer is removed to form the adhesive composition layer. get Next, the polyester resin of the adhesive composition layer is crosslinked with a crosslinking agent by subjecting the adhesive composition layer to a crosslinking treatment (for example, heat treatment), thereby forming an adhesive layer having a crosslinked structure. In this way, an adhesive layer is formed on the base material, and a laminate having the base material and the adhesive layer is obtained. As the substrate, for example, a substrate having a peeling-treated main surface, such as a release liner, may be used. The adhesive layer formed on the release liner by the above method may be transferred (transferred) onto the support (or another release liner). As a method of applying the adhesive composition (adhesive composition solution) onto the substrate, a known method can be adopted. Examples include roll coat, gravure coat, reverse roll coat, roll brush coat, air knife coat, spray coat, extrusion coat using a die coater, etc.

[Example of preferred configuration of light guide layer, optical sheet, base layer, and low refractive index layer]

Preferred examples of each component of the lighting device according to the embodiment of the present invention will be described.

The light guide layer 80 may be formed of a known material that has high transmittance to visible light. The light guide layer 80 is made of, for example, acrylic resin such as polymethyl methacrylate (PMMA), polycarbonate (PC) resin, cycloolefin resin, glass (for example, quartz glass, alkali-free glass, borosilicate glass). made of glass). The refractive index n _GP of the light guide layer 80 is, for example, 1.40 or more and 1.80 or less. In addition, unless otherwise specified, the refractive index refers to the refractive index measured with an ellipsometer at a wavelength of 550 nm. The thickness of the light guide layer 80 can be appropriately set depending on the intended use. The thickness of the light guide layer 80 is, for example, 0.05 mm or more and 50 mm or less.

The first optical sheet 10a can be produced, for example, by the method described in Japanese Patent Publication No. 2013-524288. Specifically, for example, the surface of a polymethyl methacrylate (PMMA) film is coated with a lacquer (e.g., Fine Cure RM-64 manufactured by Sanyo Kasei Kogyo Co., Ltd.: an acrylate-based photocurable resin), and the lacquer is included. The first optical sheet 10a can be manufactured by embossing an optical pattern on the film surface and then curing the lacquer (e.g., ultraviolet irradiation conditions: D valve, 1000 mJ/cm2, 320 mW/cm2). .

Examples of the material of the second optical sheet 30 include thermoplastic resins having light transparency, and more specifically, (meth)acrylic resins such as polymethyl methacrylate (PMMA), or A film formed of polycarbonate (PC)-based resin or the like can be mentioned. The second optical sheet 30 can be made of any suitable material depending on the purpose.

The thickness of the base material layer is, for example, 1 μm or more and 1000 μm or less, preferably 10 μm or more and 100 μm or less, and more preferably 20 μm or more and 80 μm or less. The refractive index of the base layer is preferably 1.40 or more and 1.70 or less, and more preferably 1.43 or more and 1.65 or less.

The refractive index n _L1 of the low refractive index layer is each independently preferably, for example, 1.30 or less, more preferably 1.20 or less, and still more preferably 1.15 or less. The low refractive index layer is preferably solid, and the refractive index is preferably 1.05 or more, for example. The difference between the refractive index of the light guide layer 80 and the refractive index layer of the low refractive index layer is preferably 0.20 or more, more preferably 0.23 or more, and even more preferably 0.25 or more. A low refractive index layer having a refractive index of 1.30 or less can be formed using, for example, a porous material. The thickness of the low refractive index layer is each independently, for example, 0.3 μm or more and 5 μm or less.

When the low refractive index layer is a porous material with voids inside, the porosity is preferably 35 volume% or more, more preferably 38 volume% or more, and particularly preferably 40 volume% or more. Within this range, a low refractive index layer with a particularly low refractive index can be formed. The upper limit of the porosity of the low refractive index layer is, for example, 90 volume% or less, and is preferably 75 volume% or less. Within this range, a low refractive index layer with excellent strength can be formed. Porosity is a value calculated from Lorentz-Lorenz's formula from the refractive index value measured with an ellipsometer.

For the low refractive index layer, for example, a low refractive index layer with voids disclosed in International Publication No. 2019/146628 can be used. The entire disclosure of International Publication No. 2019/146628 is incorporated herein by reference. Specifically, the low refractive index layer having voids is composed of substantially spherical particles such as silica particles, silica particles having micropores, and hollow silica nanoparticles, fibrous particles such as cellulose nanofibers, alumina nanofibers, and silica nanofibers, and bentonite. Includes flat particles such as nanoclay. In one embodiment, the low refractive index layer having voids is a porous body formed by direct chemical bonding of particles (for example, microporous particles) to each other. In addition, at least a part of the particles constituting the low refractive index layer having voids may be bonded to each other via a small amount (for example, the mass of the particle or less) of the binder component. The porosity and refractive index of the low refractive index layer can be adjusted by the particle size and particle size distribution of the particles constituting the low refractive index layer.

Methods for obtaining a low refractive index layer having voids include, for example, Japanese Patent Application Laid-Open No. 2010-189212, Japanese Patent Application Laid-Open No. 2008-040171, Japanese Patent Application Laid-Open No. 2006-011175, International Publication No. 2004/113966, and Methods described in their references may be cited. The entire disclosures of JP2010-189212, JP2008-040171, JP2006-011175, and International Publication No. 2004/113966 are incorporated herein by reference.

As a low refractive index layer having pores, a silica porous body can be preferably used. The silica porous body is manufactured, for example, by the following method. silicon compounds; A method of hydrolyzing and polycondensing at least one of hydrolysable silanes and/or silsesquioxane, and a partial hydrolyzate and dehydration condensate thereof, a method using porous particles and/or hollow fine particles, and a spring back. Examples include a method of generating an airgel layer using a phenomenon, a method of pulverizing a gel-like silicon compound obtained by a sol-gel method, and a method of using a pulverized gel in which the obtained pulverized fine pore particles are chemically bonded to each other using a catalyst or the like. However, the low refractive index layer is not limited to the silica porous body, and the manufacturing method is not limited to the exemplified manufacturing method, and may be manufactured by any manufacturing method. However, the porous layer is not limited to the silica porous body, and the manufacturing method is not limited to the exemplified manufacturing method, and may be manufactured by any manufacturing method. In addition, silsesquioxane is a silicon compound whose basic structural unit is (RSiO _1.5 , R is a hydrocarbon group), and although it is strictly different from silica whose basic structural unit is SiO ₂ , it has a network structure crosslinked by siloxane bonds. Since it is common with silica in that it has , herein, a porous body containing silsesquioxane as a basic structural unit is also called a silica porous body or a silica-based porous body.

A porous silica body may be composed of microporous particles of a gel-like silicon compound bonded to each other. Examples of microporous particles of the gel-like silicon compound include pulverized particles of the gel-like silicon compound. The silica porous body can be formed, for example, by applying a coating liquid containing a pulverized gel-like silicon compound to a substrate. The pulverized body of the gel-like silicon compound can be chemically bonded (for example, siloxane bond) by the action of a catalyst, light irradiation, heating, etc.

Example

[Example 1]

(1) Preparation of polyester resin A

A stirrer, a thermometer, a nitrogen introduction tube, and a cooling tube equipped with a trap were attached to a four-necked separable flask, and in this flask, 47 g of terephthalic acid (molecular weight: 166) and 45 g of isophthalic acid (molecular weight: 166) were added as carboxylic acid components. and, as alcohol components, 115 g of polytetramethylene glycol (molecular weight: 566), 4 g of ethylene glycol (molecular weight: 62), 16 g of neopentyl glycol (molecular weight: 104), and 23 g of cyclohexanedimethanol (molecular weight: 144), and as a catalyst. 0.1 g of tetrabutyl titanate was added, the temperature was raised to 240°C while stirring while the inside of the flask was filled with nitrogen gas, and the temperature was maintained at 240°C for 4 hours.

After that, the nitrogen introduction pipe and the cooling pipe equipped with the trap were removed, replaced with a vacuum pump, and the temperature was raised to 240°C while stirring in a reduced pressure atmosphere (0.002 MPa) and maintained at 240°C. The reaction was continued for about 6 hours to obtain polyester resin A. Polyester resin A was obtained by polymerizing the above monomer without using a solvent. The mass average molecular weight (Mw) of polyester resin A measured by GPC was 59,200. The prepared polyester resin A was taken out from the flask while dissolving in ethyl acetate, and a polyester resin A solution having a solid content concentration of 50% by mass was prepared.

(2) Preparation of adhesive composition solution

With respect to 100 parts by mass of solid content of the polyester resin A solution prepared above, zirconium tetraacetylacetonate (brand name "Orgatics ZC-162", manufactured by Matsumoto Fine Chemicals Co., Ltd.) as a crosslinking catalyst. "Orgatics" is a registered trademark. Hereinafter, it may be called "ZC-162"), 0.07 parts by mass, an isocyanurate form of hexamethylene diisocyanate (brand name "Coronate HX", manufactured by Tosoh Corporation) as a crosslinking agent. "Coronate" is Registered trademark. Hereinafter sometimes referred to as “Coronate HX”) was mixed with 12 parts by mass of acetylacetone as a catalyst reaction inhibitor, and ethyl acetate was further added so that the solid concentration was 20% by mass. , an adhesive composition solution (sometimes referred to as “polyester adhesive composition solution A”) was prepared.

(3) Production of adhesive sheets

The adhesive composition solution was applied to one side of the silicone release-treated substrate (first separator) to form an adhesive composition solution layer. As the first separator, a polyethylene terephthalate (PET) film (brand name “MRF38”, manufactured by Mitsubishi Chemical Corporation) with a thickness of 38 μm was used. The thickness of the adhesive composition solution layer was applied so that the thickness of the adhesive layer after the process of treatment at 40°C for 3 days below was 10 μm. The solvent in the adhesive composition solution layer was removed by drying the adhesive composition solution layer at 150°C for 1 minute, and an adhesive composition layer was obtained. Next, the adhesive composition layer was bonded to the peeled surface of another substrate (second separator) that had undergone silicone peeling treatment, and left at 40°C for 3 days. As the second separator, a biaxially stretched polyethylene terephthalate film (manufactured by Mitsubishi Chemical Corporation, brand name: Diafoil T302, hereinafter sometimes referred to as “T302”) with a thickness of 75 μm was used. By treating the adhesive composition layer at 40°C for 3 days, the polyester resin A of the adhesive composition layer was crosslinked with a crosslinking agent to form an adhesive layer. In this way, an adhesive sheet (laminated body) having a laminated structure of first separator (PET film)/adhesive layer/second separator (PET film) was produced. Even in the process of treating the adhesive composition solution layer at 150°C for 1 minute, a partial crosslinking reaction of the polyester resin A may occur, but most of the crosslinking reaction occurs during the subsequent heat treatment process at 40°C for 3 days.

(4) Preparation of concavo-convex shape film A

The uneven shape film A was manufactured according to the method described in Japanese Patent Publication No. 2013-524288. Specifically, the surface of a polymethyl methacrylate (PMMA) film was coated with lacquer (Fine Cure RM-64, manufactured by Sanyo Kasei Kogyo Co., Ltd.), and an optical pattern was embossed on the surface of the film containing the lacquer. By processing and then hardening the lacquer, the desired concave-convex shape film was produced. The total thickness of the uneven shape film A was 130 μm, and the haze value was 0.8%.

A plan view of a part of the produced uneven shaped film A as seen from the uneven surface side is shown as the uneven shaped film 70 in FIG. 9A. Additionally, a cross-sectional view taken along line 9B-9B' of the concavo-convex shape film 70 in FIG. 9A is shown in FIG. 9B. A plurality of concave portions 74 having a triangular cross-section, having a length L of 86 μm, a width W of 9.2 μm, and a depth H of 10 μm, were arranged at intervals of a width E (155 μm) in the X-axis direction. Additionally, the pattern of these concave portions 74 was arranged at intervals of width D (100 μm) in the Y-axis direction. The pitch Px of the concave portion 74 in the The density of the concave portions 74 on the surface of the uneven shaped film was 3612/cm2. In Fig. 9B, the inclination angle θa is 49°, the inclination angle θb is 85°, and the occupied area ratio Rr of the concave portion 74 when the film is viewed planarly from the uneven surface side is 4.05%.

(5) Fabrication of optical laminate

An optical laminate was produced as follows using the adhesive sheet obtained in (3) above and the concavo-convex shape film A in (4) above.

In the adhesive sheet obtained in (3) above, that is, a laminate having a laminate structure of a first separator/adhesive layer/second separator, one main surface of the adhesive layer is bonded to the peeling treated surface of the first separator, and the adhesive layer The other main surface is joined to the peeling surface of the second separator. First, the first separator is peeled from the adhesive sheet obtained in (3) above, and the exposed surface of the adhesive layer (one major surface) is covered with an acrylic resin film (thickness: 30 μm) with a nip including a driving roll and a driven roll. By bonding between rollers, a laminate having a laminate structure of acrylic resin film/adhesive layer/second separator was obtained. Subsequently, the second separator is peeled from the obtained laminate, and the surface of the exposed adhesive layer (the other main surface) is placed on the surface having the concavo-convex structure of the concavo-convex shape film A of (4), including the driving roll and the driven roll. By bonding between nip rollers, an optical laminate having a laminated structure of acrylic resin film/adhesive layer/concavo-convex shape film A was obtained. In joining the laminate of the adhesive layer and the acrylic resin film and the concavo-convex shape film A, the nip pressure between the nip rollers including the drive roll and the driven roll was as shown in Tables 1A to 1C. As a result, a long optical laminate with a width of 300 mm having a laminated structure of acrylic resin film/adhesive layer/concavo-convex shape film A was obtained.

In the optical laminate, the main surface of the adhesive layer that has been bonded to the peeling-treated surface of the second separator is bonded to the surface having the concavo-convex structure of the concavo-convex shape film A. The arithmetic mean roughness Ra of the peeled surface of T302 used as the second separator was 0.02 μm, and the maximum height Rz was 0.15 μm.

[Example 2]

An optical laminate was produced in the same manner as in Example 1 except that the thickness of the adhesive layer was changed as shown in Tables 1A to 1C.

[Example 3]

An optical laminate was produced in the same manner as in Example 2, except that the nip pressure between nip rollers and the type of the second separator were changed as shown in Tables 1A to 1C. In Example 3, a commercially available ultra-high retardation polyethylene terephthalate film with a thickness of 38 μm (Mitsubishi Chemical Co., Ltd.) was used as a separator bonded to the main surface of the second separator (PET film), that is, the adhesive layer, to be bonded to the concavo-convex shape film A. Kaisha product, brand name: Diafoil MRF38CK (hereinafter sometimes referred to as “38CK”) was used. The arithmetic average roughness Ra of the peeled surface (surface in contact with the adhesive layer) of 38CK used as the second separator was 0.01 μm, and the maximum height Rz was 0.10 μm.

[Example 4]

An optical laminate was produced in the same manner as in Example 3 except that instead of the uneven shaping film A, the uneven shaping film B was used.

In the uneven shaped film B, the area ratio Rr occupied by the concave portion when the film was viewed planarly from the uneven surface side was 66%. The uneven shape film B has a higher occupied area ratio of the concave portion than the uneven shape film A. A plan view of a part of the used uneven shaping film B as seen from the uneven surface side is shown as the uneven shaping film 52 in FIG. 14A. Additionally, a cross-sectional view taken along line 14B-14B' in FIG. 14A is shown in FIG. 14B. When the uneven shaping film 52 was viewed from the uneven surface side, the ratio of the area of the concave portion 54 to the entire area of the uneven shaping film 52 was 66%. The concave portions 54 of the concavo-convex shape film 52 are continuous in the X direction (grooves extending in the X direction) and arranged at predetermined intervals in the Y direction. The cross-sectional shape of the concave portion 54 is a triangle with a depth H of 6.78 μm, a maximum width of 6.5 μm, an inclination angle θa of 50°, and an inclination angle θb of 85°. The width of the concave portion 54 changes at a period of 17 μm. When the concavo-convex shape film 52 is used in a lighting device, for example, it is arranged so that the concave portion 54 is convex toward the light source when viewed in a plan view.

[Example 5]

An optical laminate was produced in the same manner as in Example 4 except that the thickness of the adhesive layer was changed as shown in Tables 1A to 1C.

[Example 6]

An optical laminate was produced in the same manner as in Example 2 except that the following adhesive layer was used. The adhesive layer was produced as follows.

(1) Preparation of acrylic polymer solution

First, an acrylic polymer was prepared. In a four-necked flask equipped with a stirring blade, thermometer, nitrogen gas introduction tube, and condenser, 74.6 parts by mass of n-butylacrylate (BA), 18.6 parts by mass of 4-acryloylmorpholine (ACMO), and 6.5 parts by mass of acrylic acid (AA). parts by mass, 0.3 parts by mass of 4-hydroxybutylacrylate (4HBA), and 0.1 parts by mass of 2,2'-azobisisobutyronitrile as a polymerization initiator were injected into the flask together with ethyl acetate so that the total of monomers was 50% by mass. Then, while gently stirring, nitrogen gas was introduced and purged with nitrogen for 1 hour, and then the liquid temperature in the flask was maintained at around 58°C and a polymerization reaction was performed for 8 hours to obtain an acrylic polymer. Here, after 2 hours had elapsed from the start of the polymerization reaction, ethyl acetate was added dropwise over 3 hours so that the solid content was 35% by mass. That is, the acrylic polymer was obtained as an acrylic polymer solution with a solid content of 35% by mass.

(2) Preparation of adhesive composition solution

Subsequently, to the obtained acrylic polymer solution, 10 parts by mass of ultraviolet curable urethane acrylate resin A (mass average molecular weight Mw: 5,500) as solid content per 100 parts by mass of polymer, and 4-(2-hydroxyethoxy as a photopolymerization initiator) ) 1.0 parts by mass of phenyl (2-hydroxy-2-propyl) ketone (trade name “Omnirad2959”, manufactured by IGM Japan Kodo Kaiser), and 1,3-bis (N, N-diglycidylaminomethyl) cyclo as a crosslinking agent. An adhesive composition solution (sometimes referred to as "acrylic adhesive composition solution A") was prepared by mixing 0.6 parts by mass of hexane (brand name "TETRAD-C", manufactured by Mitsubishi Gas Chemical Co., Ltd.).

(3) Production of adhesive sheets

Acrylic adhesive composition solution A was applied to one side of a 38-μm-thick polyethylene terephthalate (PET) film (product name "MRF38", manufactured by Mitsubishi Chemical Corporation) that had been subjected to silicone release treatment to form an adhesive composition solution layer. At this time, the thickness of the adhesive composition solution layer was applied so that the thickness after drying (that is, the thickness of the adhesive composition layer) was 5 μm. By drying the adhesive composition solution layer at 150°C for 3 minutes, the solvent in the adhesive composition solution layer was removed and the acrylic polymer was crosslinked with a crosslinking agent, thereby obtaining an adhesive layer having a crosslinked structure formed by the acrylic polymer and the crosslinking agent. Here, the adhesive layer was obtained without curing the ultraviolet curable resin of the adhesive composition solution. The obtained adhesive layer does not have a crosslinked structure formed by curing the ultraviolet curable resin. Next, the adhesive composition layer was bonded to the peeled surface of a polyethylene terephthalate (PET) film (product name “MRE38”, manufactured by Mitsubishi Chemical Corporation) with a thickness of 38 μm that had been subjected to silicone peeling treatment, forming PET film/adhesive layer/PET film. An adhesive sheet having a laminated structure was produced.

An optical laminate was produced in the same manner as Example 2 using the adhesive sheet obtained in (3) above.

[Example 7]

An optical laminate was produced in the same manner as in Example 6, except that the thickness of the adhesive layer was changed as shown in Tables 1A to 1C.

[Example 8]

An optical laminate was produced in the same manner as in Example 7, except that the nip pressure between nip rollers was changed as shown in Tables 1A to 1C.

[Example 9]

An optical laminate was produced in the same manner as in Example 6, except that the nip pressure between nip rollers was changed as shown in Tables 1A to 1C.

[Example 10]

An optical laminate was produced in the same manner as in Example 9, except that the thickness of the adhesive layer was changed as shown in Tables 1A to 1C.

[Example 11]

An optical laminate was produced in the same manner as in Example 9 except that instead of the uneven shaping film A, the uneven shaping film B was used.

[Example 12]

An optical laminate was produced in the same manner as in Example 11, except that the thickness of the adhesive layer was changed as shown in Tables 1A to 1C.

[Example 13]

(1) Preparation of acrylic polymer solution

First, an acrylic polymer was prepared. In a four-necked flask equipped with a stirring blade, thermometer, nitrogen gas introduction tube, and condenser, 90.7 parts by mass of n-butylacrylate (BA), 6.3 parts by mass of 4-acryloylmorpholine (ACMO), and 2.7 parts by mass of acrylic acid (AA). parts by mass, 0.3 parts by mass of 4-hydroxybutylacrylate (4HBA), and 0.1 parts by mass of 2,2'-azobisisobutyronitrile as a polymerization initiator were injected into the flask together with ethyl acetate so that the total of monomers was 50% by mass. Then, while gently stirring, nitrogen gas was introduced and purged with nitrogen for 1 hour, and then the liquid temperature in the flask was maintained at around 58°C and a polymerization reaction was performed for 8 hours to obtain an acrylic polymer. Here, after 2 hours had elapsed from the start of the polymerization reaction, ethyl acetate was added dropwise over 3 hours so that the solid content was 35% by mass. That is, the acrylic polymer was obtained as an acrylic polymer solution with a solid content of 35% by mass.

(2) Preparation of adhesive composition solution

To the obtained acrylic polymer solution, with respect to 100 parts by mass of solid content (polymer), 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane (trade name "TETRAD-C", Mitsubishi Gas Chemical Co., Ltd.) was added as a crosslinking agent. An adhesive composition solution (sometimes referred to as “acrylic adhesive composition solution B”) containing 0.1 parts by mass (manufactured by Shikigai Co., Ltd.) was prepared.

(3) Production of adhesive sheets

Acrylic adhesive composition solution B was applied to one side of a 38-μm-thick polyethylene terephthalate (PET) film (product name “MRF38”, manufactured by Mitsubishi Chemical Corporation) that had undergone silicone release treatment to form an adhesive composition solution layer. At this time, the thickness of the adhesive composition solution layer was applied so that the thickness after drying (that is, the thickness of the adhesive composition layer) was 5 μm. By drying the adhesive composition solution layer at 150°C for 3 minutes, the solvent in the adhesive composition solution layer was removed and the acrylic polymer was crosslinked with a crosslinking agent, thereby obtaining an adhesive layer having a crosslinked structure formed by the acrylic polymer and the crosslinking agent. Next, the adhesive composition layer was bonded to the peeled surface of a polyethylene terephthalate (PET) film (product name “MRE38”, manufactured by Mitsubishi Chemical Corporation) with a thickness of 38 μm that had been subjected to silicone peeling treatment, forming PET film/adhesive layer/PET film. An adhesive sheet having a laminated structure was produced.

(4) Preparation of uneven shape film A

It was carried out similarly to Example 1.

(5) Fabrication of optical laminate

Using the adhesive sheet obtained in (3) above and the concavo-convex shape film A of (4), an optical laminate was produced in the same manner as in Example 1, except that the nip pressure between nip rollers was changed as shown in Tables 1A to 1C.

[Example 14]

(1) Preparation of acrylic polymer solution

It was carried out similarly to Example 13.

(2) Preparation of adhesive composition solution

To the obtained acrylic polymer solution, based on 100 parts by mass of solid content, 0.25 parts by mass of dibenzoyl peroxide (1-minute half-life: 130°C) as a cross-linking agent, and a polyisocyanate-based cross-linking agent consisting of a trimethylolpropane adduct of tolylene diisocyanate (Nippon) 0.15 parts by mass of polyurethane Kogyo Co., Ltd., Coronate L), and 0.075 parts by mass of a silane coupling agent (3-glycidoxypropyltrimethoxysilane; manufactured by Shinetsu Chemical Co., Ltd., product name "KBM-403") were blended. An adhesive composition solution (sometimes referred to as “acrylic adhesive composition solution C”) was prepared.

(3) Production of adhesive sheets

The acrylic adhesive composition solution C obtained in (2) above was used, and the thickness of the adhesive layer was changed as shown in Tables 1A to 1C, in the same manner as in Example 13.

(4) Preparation of uneven shape film A

It was carried out similarly to Example 13.

(5) Fabrication of optical laminate

It was carried out similarly to Example 13.

[Example 18]

An optical laminate was produced in the same manner as in Example 14, except that the thickness of the adhesive layer was changed as shown in Tables 1A to 1C.

[Example 15]

An optical laminate was produced in the same manner as in Example 14, except that the nip pressure between nip rollers was changed as shown in Tables 1A to 1C.

[Example 16]

An optical laminate was produced in the same manner as in Example 15, except that the thickness of the adhesive layer was changed as shown in Tables 1A to 1C.

[Example 17]

An optical laminate was produced in the same manner as in Example 13 except that the thickness of the adhesive layer and the nip pressure between nip rollers were changed as shown in Tables 1A to 1C, and uneven shaping film B was used instead of uneven shaping film A.

[Comparative Example 2]

(1) Preparation of acrylic polymer solution

It was carried out similarly to Example 13.

(2) Preparation of adhesive composition solution

To the obtained acrylic polymer solution, 0.15 parts by mass of trimethylolpropane/tolylene diisocyanate trimer adduct (manufactured by Tosoh Corporation, brand name Coronate L) as a crosslinking agent and dibenzoyl peroxide (Nippon Yushi) were added to the obtained acrylic polymer solution, based on 100 parts by mass of the polymer. An adhesive composition solution (sometimes referred to as “acrylic adhesive composition solution D”) was prepared by mixing 0.075 parts by mass of Niper BMT40 (SV), manufactured by Co., Ltd.

An optical laminate was produced in the same manner as in Example 13, except that the nip pressure between nip rollers was changed as shown in Tables 1A to 1C.

[measurement method]

The measurement conditions for each characteristic are as follows.

<Area ratio of bubbles>

The optical laminated bodies manufactured in Examples and Comparative Examples were cut into 10 cm x 10 cm, and five locations among them were observed under a microscope. The observation method at that time was to acquire images with an optical microscope in a field of view of 3.5 mm /entire viewing area). The minimum size of bubbles detectable with an optical microscope was 1.7 ㎛ (the size of 1 pixel (pixel resolution) is a square of 1.7 ㎛ × 1.7 ㎛).

<Height of the adhesive layer present in the concave portion of the uneven shaped film>

A cross section of the produced optical laminate was cut out, and for each concave portion, the height of the adhesive layer present in the concave portion was measured using SEM. Specifically, first, the optical laminate produced in each example and comparative example was cut to a size of 5 mm x 5 mm. After that, the cut test piece was cooled, a cross-section was prepared by FIB processing (Helios G4 UX DualBeam System manufactured by FEI), and the cross-section was observed by SEM.

<Surface roughness Ra, Rz of adhesive layer>

The separator (PET film) on one side was peeled from the adhesive sheet obtained in each of the examples and comparative examples, and the roughness of the surface of the exposed adhesive layer was measured with a non-contact shape measuring device (NewView7300, manufactured by ZYGO). The measurement method was in accordance with the method described in JIS B0601-2001, and the arithmetic mean roughness Ra and maximum height Rz of the surface of the adhesive layer were measured. “-” in Tables 1A to 1C indicates not measured.

<Nip pressure (laminate pressure), pressure applied to the flat part>

To measure the nip pressure (lamination pressure) between rolls, pressure-sensitive paper (Fuji Film Co., Ltd., Pressscale 3LW) was attached to the entire nipped width of the roll (width 250 mm, diameter 200 mm), and the pressure (Mpa) was measured. . In Tables 1A to 1C, the average value over the entire width to be nipped is described as "nip pressure (laminate pressure) Pl". In addition, in the roll used here, pressure unevenness in the TD direction schematically shown in FIG. 6 did not substantially occur. Non-uniformity in pressure in the TD direction schematically shown in FIG. 6 tends to occur when the ratio of the width of the roll (length in the TD direction) to the diameter of the roll is large.

The pressure Pf applied to the flat part (i.e., the pressure applied to parts other than the concave part) is the value of the nip pressure between the rolls measured as above, assuming that no pressure is applied to the concave part of the surface of the uneven shaped film, It was converted by subtracting the area of the concave portion as shown in the formula below. The occupied area ratio Rr of the concave portion used the value in the design of the concavo-convex shape film.

(Pressure Pf applied to the flat part)=(Nip pressure Pl)/(1-occupied area ratio of the concave part Rr)

<Compressive stress-strain curve of adhesive layer>

Figure 18 is a schematic perspective view for explaining the method of measuring the compressive stress-strain curve of the adhesive layer. Each adhesive layer 20a (thickness 20 μm) of the example was cut to a size of approximately 10 mm × 10 mm (width and height 10 mm), placed on the acrylic film 41, and Pt-Pd deposition was performed for 30 seconds, It was fixed to a predetermined support, nanoindentation measurement was performed, and a compressive stress-strain curve was obtained. The measurement result is output as, for example, load (N) relative to displacement (mm), and the stress is obtained by dividing the load by the area of the indenter, and the strain is obtained by dividing the displacement by the thickness of the adhesive layer, thereby creating a compressive stress-strain curve. got it Using the obtained data, the compressive stress (y)-strain curve (x) was fitted with the approximate equation y=a× ^xb .

(Analysis device/measurement conditions)

Device: TriboIndenter from Hysitron Inc.

Indenter used: Flat (radius of cylinder ra=97.87㎛)

Measurement method: single indentation measurement

Indentation depth setting: 2㎛

Measurement temperature: room temperature

<180° peel adhesion of adhesive layer to optical sheet>

FIGS. 19A, 19B, and 19C are schematic cross-sectional views, top views, and cross-sectional views for explaining a method of measuring the 180° peel adhesion of an adhesive layer to an optical sheet.

As shown in FIG. 19A, on an acrylic plate 42 (thickness 3 mm), an acrylic adhesive layer 49A (thickness 100 μm) is interposed, and an uneven shape film 70 (irregular shape film A) (thickness 130 μm) is formed. ), and the adhesive layer 20a (thickness 15 μm) of each example were arranged in this order. On the adhesive layer 20a, a 25 mm wide adhesive layer having a laminated structure of acrylic film 43 (thickness 20 μm)/acrylic adhesive layer 49B (thickness 100 μm)/PET film 44 (thickness 75 μm) The film laminate (40f) was bonded and a 180° peel test was performed. A PET film (thickness 38㎛) is sandwiched between the adhesive layer 20a and the concavo-convex shaping film 70 (arrow in FIG. 19a), and peeling occurs at the interface between the adhesive layer 20a and the concavo-convex shaping film 70. did. The uneven shaped film 70 is positioned so that the inclined surface with the inclination angle θa (49°) of the concave portion 74 is further away from the location where the film laminate 40f is bent than the inclined surface with the inclination angle θb (85°). The acrylic adhesive layers 49A and 49B are known general-purpose adhesives.

(Device/Measurement Conditions)

Device: Autograph AGT-5N (made by Shimazu Seisakusho Co., Ltd.)

Peel speed: 150mm/min

Measurement temperature: room temperature

For examples using an adhesive layer formed from acrylic adhesive composition solution A, B or C, 1640 points were measured at equal intervals in the range of 20 mm to 40 mm from the end (peel-off start point), and the average value was calculated to obtain a 180° peel. Adhesion (N/25mm) was obtained. For the Example using the adhesive layer formed from the polyester adhesive composition solution A, 2440 points were measured at equal intervals in the range of 10 mm to 40 mm from the end, and the average value was obtained to obtain a 180° peel adhesive force (N/25 mm). . The stress Sp (MPa) was obtained by dividing the obtained 180° peel adhesive force (N/25 mm) by the cross-sectional area of the film (i.e., cross-sectional area of the film laminated body 40f, 25 mm x 195 μm).

<Calculated landfill volume Dd>

The calculated embedding amount Dd of the adhesive layer in each example was calculated. Tables 1A to 1C show the calculated landfill amount Dd calculated using two methods. The calculated embedding amount Dd(1) selects the closest value from the measurement results of compressive stress without using the approximation equation y=a×x ^b for the compressive stress (y)-strain (x) curve of the adhesive layer 20a. The calculated embedding amount Dd(2) was calculated using the approximate formula y=a× ^xb for the compressive stress (y)-strain (x) curve of the adhesive layer 20a. The embedding amount dmax shown in Tables 1A to 1C is the strain with respect to the pressure Pf applied to the flat portion in the compressive stress-strain curve of the adhesive layer 20a multiplied by the thickness Dt of the adhesive layer 20a. The value was set to dmax. Landfill volume dmax was also calculated in two ways. The embedding amount dmax(1) selects the closest value from the measurement results of compressive stress without using the approximation formula y=a×x ^b of the compressive stress (y)-strain (x) curve of the adhesive layer 20a, , dmax(2) was calculated using the approximate equation y=a× ^xb for the compressive stress (y)-strain (x) curve of the adhesive layer 20a. dmax(1) was used to calculate the calculated landfill amount Dd(1), and dmax(2) was used to calculate the calculated landfill amount Dd(2).

The evaluation results are shown in Table 1A, Table 1B, Table 1C, Figure 10, and Figure 17. “-” in Tables 1A to 1C indicates that no measurement or calculation was performed. Figure 10 is a graph showing evaluation results of the area ratio (%) of bubbles and the height (μm) of the adhesive layer present in the concave portion in the optical laminates of Examples 1 to 18. In Figure 10, Examples 1 to 5 using polyester adhesive composition solution A are circles or triangles hatched with diagonal lines, and Examples 6 to 12 using acrylic adhesive composition solution A are black circles or triangles. , Examples 13 to 18 using acrylic adhesive composition solution B or C show the results as white circles or triangles, those using the uneven shape film A show the results as circles, and those using the uneven shape film B show the results as triangles. . Additionally, the results of Comparative Example 2 are not shown in Figures 10 and 17. Figure 17 is a graph showing the correlation between the measured value (μm) of the height of the adhesive layer present in the concave portion and the calculated embedding amount Dd(1) (μm) in the optical laminates of Examples 1 to 18. . Each result of Examples 1 to 18 is indicated by the same symbol as in FIG. 10.

In addition, the measurement of the 180° peel adhesive force of the adhesive layer to the optical sheet was performed only using the uneven shaping film A, and the measurement using the uneven shaping film B was not performed. In Tables 1A to 1C, “180° peel adhesion” and “stress Sp obtained from peel adhesion” for the examples using the uneven shape film B (Examples 4, 5, 11, 12 and 17) are the same adhesive layer The measurement results of the 180° peel adhesive force for the uneven-shaped film A using , and the value of stress Sp obtained therefrom are described. In the examples using the concavo-convex shape film B, calculations of "Sp "Stress F2 obtained from the peeling adhesive force of the adhesive layer 20a to the first optical sheet 10a" explained with reference to FIG. 16A is strictly speaking the concave portion 14 with the inclination angle θa of the adhesive layer 20a. ) is the stress obtained from the peeling adhesion force on the inclined surface. However, since it is difficult to actually measure the peel adhesive force of the adhesive layer 20a with respect to the inclined surface of the concave portion 14, the present inventors used Measure the 180° peel adhesive force of the adhesive layer 20a, and calculate the embedding amount Dd using the result regardless of the density of the concave portion of the optical sheet (concavo-convex shaped film) bonded to the adhesive layer 20a. Thought. The smaller the density of the concave portions 14 on the first main surface 12s of the first optical sheet 10a, the larger the proportion of the flat portions 10s, so the closer it is to a flat surface, the more effective the measurement of the 180° peel adhesive force is. I think it's appropriate. Considering this, in measuring the 180° peel adhesive force of the adhesive layer 20a with respect to the first main surface 12s (flat portion 10s) of the first optical sheet 10a, the concave-convex shape with a small density of concave portions Film A was used.

[Table 1A]

[Table 1B]

[Table 1C]

In the optical laminates of Examples 1 to 17, the area ratio of bubbles present at the interface between the flat portion and the adhesive layer is 3% or less, and the height of the adhesive layer present in the plurality of concave portions is 2 μm or less. . In contrast, the optical laminate of Example 18 and Comparative Example 2 had an area ratio of bubbles present at the interface between the flat portion and the adhesive layer exceeding 3%, and/or a height of the adhesive layer present within the plurality of concave portions. It is more than 2㎛. The optical laminate of Example 14 and the optical laminate of Example 18 were produced with a difference only in the thickness Dt of the adhesive layer on the flat portion, but the area ratio of air bubbles present at the interface between the flat portion and the adhesive layer was that of Example 14. In the optical laminate of Example 18, the content is suppressed to 3% or less, but in the optical laminate of Example 18, it is more than 3%. From these results, it is preferable that the thickness Dt of the adhesive layer on the flat portion is, for example, 2 μm or more. The thickness Dt of the adhesive layer may be, for example, 3 μm or more. The upper limit of the thickness Dt of the adhesive layer is not particularly limited, and is, for example, 10 μm or less. However, the area ratio of air bubbles present at the interface between the flat part and the adhesive layer is determined not only by the thickness of the adhesive layer on the flat part, but also by the pressure applied to the adhesive layer and the optical sheet when bonding the adhesive layer and the optical sheet, and the adhesive layer. This is due to the surface roughness of the surface of the separator used during production (specifically, the surface roughness of the surface of the separator bonded to the surface of the adhesive layer bonded to the surface having the uneven structure of the optical sheet), the gel fraction of the adhesive layer, etc. It can change. The degree of penetration of the adhesive layer into the plurality of concave portions of the uneven structure (height of the adhesive layer present within the concave portions) may also vary depending on the manufacturing conditions of the adhesive layer or the physical properties of the adhesive layer. For example, even if the same adhesive composition solution is used, if the thickness of the adhesive layer (thickness of the adhesive layer on the flat portion) is different, the crosslinking density of the adhesive layer may be different, thereby preventing the adhesive layer from invading the plurality of concave portions. The degree may be different. Therefore, without being limited to the above-described examples, an optical laminate according to an embodiment of the present invention can be obtained by appropriately adjusting the production conditions of the adhesive layer or the physical properties of the adhesive layer.

In Examples 6 to 12 using the acrylic adhesive composition solution A, adhesive layers were produced without curing the ultraviolet curable resin contained in the acrylic adhesive composition solution A as described above. It is not limited to this, and the adhesive layer may contain a cured product of ultraviolet curable resin. That is, an adhesive layer obtained by curing the ultraviolet curable resin may be used using an acrylic adhesive composition solution containing the ultraviolet curable resin. Depending on whether or not the ultraviolet curable resin is cured, the surface roughness of the obtained adhesive layer does not change significantly, and the area ratio of bubbles in the optical laminate does not change significantly either.

As shown in FIG. 17, the calculated embedding amount Dd was compared with the measured value of the height of the adhesive layer 20a existing in the concave portion 14, and a certain correlation was confirmed. Using the calculated embedding amount Dd, an optical laminate in which penetration into the recessed portion 14 of the adhesive layer 20a is suppressed can be represented. Specifically, when the height (measured value) of the adhesive layer present in the concave portion 14 is 2 μm or less, the calculated embedding amount Dd can be said to be 1.3 μm or less.

As shown in Tables 1A to 1C, in any of the examples, that is, when any of the acrylic adhesive composition solutions A, B, and C and the polyester adhesive composition solution A were used, the calculated embedding amount Dd was 1.3 μm or less. The calculated embedding amount Dd is 1.3 ㎛ or less by any of the calculation methods (1) and (2) (i.e., whether or not the approximate formula for the compressive stress-strain curve of the adhesive layer is used), and Dd It can be seen that is less than 0.5㎛. Additionally, the lamination pressure Pl is 0.1 MPa or more. The upper limit of the lamination pressure Pl is not limited, but is, for example, 0.5 MPa or less.

As shown in Tables 1A to 1C, the compressive stress (y)-strain (x) curve of the adhesive layer formed from the polyester adhesive composition solution A is expressed by the approximate equation y = 278x ^2.19 , and the acrylic adhesive composition solution A The compressive stress (y)-strain (x) curve of the adhesive layer formed with is expressed by the approximate formula y=212x ^2.24 , and the compressive stress (y)-strain (x) of the adhesive layer formed with the acrylic adhesive composition solutions B and C The curve is expressed by the approximate equation y=28x ^2.10 . In addition, acrylic adhesive composition solutions B and C differ only in the type of crosslinking agent. The difference in crosslinking agent did not affect the compressive stress-strain curve of the formed adhesive layer. Comparing the approximation y=ax ^b of the compressive stress (y)-strain (x) curve of the adhesive layer, there is a significant difference, especially in the coefficient a. It can be said that the larger the coefficient a, the larger (harder) the compressive elastic modulus. . Among the adhesive layers used in the examples, the adhesive layer formed from the polyester adhesive composition solution A has the largest coefficient a, followed by the adhesive layer formed from the acrylic adhesive composition solution A, and then the adhesive layer formed from the acrylic adhesive composition solution B or C. As a result, the coefficient a becomes smaller.

In the examples (excluding Examples 8, 11, and 12) using acrylic adhesive composition solutions A, B, or C, the stress F2 resulting from the peel adhesive force is greater than or equal to the restoring force F1 due to compressive elasticity (F2≥F1), That is, Sp×sinθa≥Pf is satisfied, and the calculated landfill amount Dd is equal to the landfill amount dmax. The embedding amount dmax is a value obtained by multiplying the strain corresponding to Pf in the compressive stress-strain curve of the adhesive layer by the thickness Dt of the adhesive layer. These embodiments are considered to correspond to the case described with reference to FIG. 8B.

On the other hand, in Examples 8, 11, and 12 of the examples using the polyester adhesive composition solution A and the examples using the acrylic adhesive composition solution A, the stress F2 resulting from the peeling adhesive force was the restoring force F1 due to the compressive elasticity. is smaller than (F2<F1), that is, it satisfies Sp It is a value. These embodiments are considered to correspond to the case described with reference to FIG. 8A.

From the viewpoint of the magnitude of the compressive elastic modulus, a in the approximate equation y=ax ^b is preferably, for example, 150 or more, and more preferably 250 or more. b in the approximation equation y=ax ^b is not particularly limited, but may be, for example, 2 or more. The stress Sp calculated from the peeling adhesive force is, for example, 0.5 MPa or less.

In addition, depending on the purpose of the adhesive layer and the optical laminate, it can be used without being limited to the size of the compressive elastic modulus of the adhesive layer. For example, a of the approximation equation y=ax ^b may be, for example, 30 or less. The stress Sp calculated from the peeling adhesive force is, for example, 1.0 MPa or more.

The adhesive layer formed from the polyester adhesive composition solution A is an example of the adhesive layer Ac described in the above-mentioned international application PCT/JP2022/004554 by the present applicant, that is, a polyester resin that is a copolymer of a polyhydric carboxylic acid and a polyhydric alcohol. It is formed by crosslinking an adhesive composition containing a crosslinking agent and at least one crosslinking catalyst selected from the group consisting of an organic zirconium compound, an organic iron compound, and an organic aluminum compound, and the adhesive composition is maintained at a temperature of 85° C. and a relative humidity of 85% for 300 hours. The gel fraction after retention is more than 40%, and the 180° peel adhesive force to the PMMA film is more than 100mN/20mm.

The adhesive layer formed from the acrylic adhesive composition solution A is an example of the adhesive layer Aa described above in International Publication No. 2021/167090 by the present applicant, that is, in a creep test using a rotational rheometer, 10000 Pa at 50°C. The creep strain rate when applying a stress of 1 second for 1 second is 10% or less, and the creep strain rate when a stress of 10000 Pa is applied for 30 minutes at 50°C is 16% or less, and the 180° peel adhesion to the PMMA film is 10mN/ It is more than 20mm.

<Change in the degree of penetration into the concave portion of the adhesive layer during and after lamination>

Using the optical laminates of Example A and Example B below, changes in the degree of penetration into the concave portion of the adhesive layer during and after lamination were observed.

The optical laminated body of Example A is similar to the optical laminated body of Example 1, except that the optical laminated body has a laminated structure of acrylic resin film/adhesive layer/concavo-convex shaped film B so that the thickness of the adhesive layer is 300 μm. produced. The optical laminated body of Example B was made in the same manner as in Example 18, except that the optical laminated body having a laminated structure of acrylic resin film/adhesive layer/concavo-convex shape film B was produced so that the thickness of the adhesive layer was 160 μm. Here, the adhesive layer was made thick so that the penetration (burying) of the adhesive layer into the concave portion could be easily observed.

As shown in FIG. 11A, a transparent plate 150A is placed on one main surface side of the optical laminate 100S of Example A, and a transparent plate 150B is placed on the other main surface side, thereby forming a sample 1000A. . FIG. 11B is a diagram schematically showing a cross section of the sample 1000A. The transparent plate 150B is shorter than the optical laminate 100S, and the optical laminate 100S of Example A touches the corner of the transparent plate 150B. The optical laminate 100S of Example A is pressed against the corner of the transparent plate 150B, and force is applied by hand to the optical laminate 100S of Example A through the transparent plate 150A (in the drawing) arrow). The optical laminate 100S (dashed oval portion in the figure) was observed while applying force and after the force was removed.

Figure 12 shows optical images of the sample 1000A before applying force (top), the sample 1000A while applying force (middle), and the sample 1000A after the force was removed (bottom). Figure 13 shows the results of a similar evaluation using the optical laminate of Example B instead of the optical laminate of Example A. 13 , a sample with the optical laminate of Example B before force is applied (top), a sample with the optical laminate of Example B with force applied (middle), and the example after the force is removed. The optical image of the sample (bottom) having the optical laminate of B is shown.

As can be seen from FIGS. 12 and 13 , both the optical laminate of Example A and the optical laminate of Example B show the optical laminate when applying force (middle part of FIGS. 12 and 13 ) and before applying force (FIG. 12 and the top of Figure 13), there is a part where transparency is improved (the dashed oval part in the figure). This means that before force is applied, a plurality of internal spaces are formed by the uneven surface of the uneven shaping film and the adhesive layer, but when force is applied, the concave portions of the uneven shaping film are filled with the adhesive layer, forming a light distribution control structure. This is because the internal space of plurality is lost. When the applied force was removed (bottom of FIGS. 12 and 13), the transparency returned to the original in the optical laminate of Example A, but the transparency did not return with an improvement in the optical laminate of Example B. . When the optical laminate was observed with an optical microscope, it was confirmed that the pattern of a plurality of internal spaces was not observed in the portion where transparency was improved, and that no internal spaces were formed. That is, in the optical laminate of Example A, the adhesive layer that had invaded the concave portion when force was applied did not invade the concave portion (or was in a state in which intrusion into the concave portion was suppressed) when the force was removed. Returning to this, in the optical laminate of Example B, it is believed that the adhesive layer that invaded the concave portion when force was applied remained intruded into the concave portion even when the force was removed. However, here, since the adhesive layer was made thick and evaluated so that the penetration (burying) of the adhesive layer into the concave portion can be easily observed, this evaluation result is limited to the adhesive layer included in the optical laminate according to the embodiment of the present invention. It's not. As described above, in the optical laminates of Examples 14 to 16 using an adhesive layer of the same composition as the optical laminate of Example B, the area ratio of bubbles present at the interface between the flat portion and the adhesive layer was 3%. The result is that the height of the adhesive layer present in the plurality of concave portions is 2 μm or less.

The optical laminate of the present invention is widely used in optical devices such as display devices and lighting devices.

10a: first optical sheet
12s, 18s: main surface (surface)
20a: Adhesive layer
60: light source
80: light guide layer
100A, 102A, 102B: Optical laminate
200A, 200B: Lighting device

Claims (22)

A first optical sheet having a first main surface having a concavo-convex structure and a second main surface opposite to the first main surface, wherein the concavo-convex structure includes a plurality of concave portions and a flat portion between adjacent concave portions among the plurality of concave portions. Process A of preparing a first optical sheet comprising,
Process B of preparing an adhesive layer,
Comprising a step C of bonding the adhesive layer to the first main surface of the first optical sheet,
Each of the plurality of concave portions has an inclined surface at an inclination angle θa,
The stress obtained by dividing the 180° peel adhesive force of the adhesive layer with respect to the first main surface of the first optical sheet, obtained by a 180° peel test, by the film cross-sectional area is Sp,
In the step C, the pressure when bonding the adhesive layer to the first main surface of the first optical sheet is set to Pl,
In the step C, the pressure applied to the flat portion when bonding the adhesive layer to the first main surface of the first optical sheet is set to Pf,
When Sp
In the case of Sp
A method for producing an optical laminate wherein Dd is 1.3 μm or less. According to claim 1,
A manufacturing method wherein Dd is 0.5 μm or less. The method of claim 1 or 2,
A manufacturing method wherein the pressure Pl in step C is 0.1 MPa or more and 0.5 MPa or less. The method according to any one of claims 1 to 3,
The manufacturing method wherein the thickness Dt of the adhesive layer is 3 ㎛ or more and 10 ㎛ or less. The method according to any one of claims 1 to 4,
The compressive stress (y)-strain (x) curve of the adhesive layer is approximated as y=a×x ^b , a is 150 or more, and b is 2 or more. According to claim 5,
The compressive stress (y)-strain (x) curve of the adhesive layer is approximated as y=a×x ^b , and a is 250 or more. The method according to any one of claims 1 to 4,
The compressive stress (y)-strain (x) curve of the adhesive layer is approximated as y=a× ^xb , a is 30 or less, and b is 2 or more. The method according to any one of claims 1 to 7,
A manufacturing method that satisfies Sp×sinθa<Pf. The method according to any one of claims 1 to 8,
A manufacturing method wherein the stress Sp is 0.5 MPa or less. The method according to any one of claims 1 to 8,
A manufacturing method wherein the stress Sp is 1.0 MPa or more. The method according to any one of claims 1 to 10,
The adhesive layer is,
It is formed by crosslinking an adhesive composition containing a polyester resin that is a copolymer of a polyhydric carboxylic acid and a polyhydric alcohol, a crosslinking agent, and at least one crosslinking catalyst selected from the group consisting of an organic zirconium compound, an organic iron compound, and an organic aluminum compound. ,
The gel fraction is over 40% after being maintained for 300 hours at a temperature of 85°C and a relative humidity of 85%.
A manufacturing method wherein the 180° peel adhesion to the PMMA film is at least 100 mN/20 mm. The method according to any one of claims 1 to 10,
A manufacturing method wherein the adhesive layer is the following adhesive layer Aa or adhesive layer Ab.
In a creep test using a rotational rheometer, the creep strain rate when a stress of 10,000 Pa was applied for 1 second at 50°C was 10% or less, and the creep strain rate when a stress of 10,000 Pa was applied at 50°C for 30 minutes was 16%. Below,
Adhesive layer Aa, having a 180° peel adhesion to PMMA film of 10 mN/20 mm or more;
An adhesive composition containing a polymer and a curable resin is formed by curing the curable resin,
The initial tensile modulus of elasticity at 23°C before curing the curable resin of the adhesive composition is 0.35 MPa or more and 8.00 MPa or less,
Adhesive layer Ab, wherein the initial tensile modulus of elasticity at 23°C after curing the curable resin of the adhesive composition is 1.00 MPa or more. The method according to any one of claims 1 to 12,
The manufacturing method wherein the inclined surface directs a part of light propagating within the adhesive layer toward the second main surface of the first optical sheet by total internal reflection. The method according to any one of claims 1 to 13,
Each of the plurality of concave portions has a different inclined surface opposite to the inclined surface,
The manufacturing method wherein the inclination angle θa of the inclined surface is smaller than the inclination angle θb of the other inclined surface. The method according to any one of claims 1 to 14,
The process B is,
An adhesive composition solution containing a (meth)acrylic polymer and/or polyester polymer, a crosslinking agent, and a solvent is applied on the peeled main surface of a base material having a peeled main surface to form an adhesive composition solution layer. process Ba,
Step Bb of removing the solvent of the adhesive composition solution layer to form an adhesive composition layer,
A step Bc of forming another substrate having a peeling-treated main surface on the main surface opposite to the base material of the adhesive composition layer so that the peeling-treated main surface is in contact with the adhesive composition layer;
A step Bd of forming the adhesive layer by crosslinking the (meth)acrylic polymer and/or polyester polymer of the adhesive composition layer with the crosslinking agent,
The process C is,
A manufacturing method comprising a step Ca of joining the first main surface of the first optical sheet and the main surface of one side of the base material of the adhesive layer or the other base material. According to claim 15,
The manufacturing method wherein the arithmetic mean roughness Ra of the peeling-treated main surface of the substrate or the other substrate is less than 0.05 μm. According to claim 16,
A manufacturing method, wherein the maximum height Rz of the peeled main surface of the substrate or the other substrate is less than 0.5 μm. The method according to any one of claims 15 to 17,
A manufacturing method wherein the step Ca is performed by a roll-to-roll method. The method according to any one of claims 1 to 18,
When the ratio of the area of the plurality of concave portions to the area when the first optical sheet is viewed in a planar direction from the normal direction of the first main surface is Rr,
A manufacturing method wherein the pressure Pf applied to the flat portion in the step C is obtained by dividing the pressure Pl in the step C by (1-Rr). A first optical sheet having a first main surface having a concavo-convex structure and a second main surface opposite to the first main surface, wherein the concavo-convex structure includes a plurality of concave portions and a flat portion between adjacent concave portions among the plurality of concave portions. A first optical sheet comprising,
It has an adhesive layer disposed on the first main surface side of the first optical sheet and in contact with the flat portion,
The surface of the adhesive layer and the first main surface of the first optical sheet define an internal space within each of the plurality of recesses,
Each of the plurality of concave portions has an inclined surface at an inclination angle θa,
The adhesive layer is attached to the first main surface of the first optical sheet with pressure Pl,
When bonding the adhesive layer to the first main surface of the first optical sheet, the pressure applied to the flat portion is Pf,
The stress obtained by dividing the 180° peel adhesion of the adhesive layer to the first main surface of the first optical sheet by the 180° peel test by the film cross-sectional area is Sp,
When Sp
In the case of Sp
An optical laminate having a Dd of 1.3 μm or less. According to claim 20,
The adhesive layer is,
It is formed by crosslinking an adhesive composition containing a polyester resin that is a copolymer of a polyhydric carboxylic acid and a polyhydric alcohol, a crosslinking agent, and at least one crosslinking catalyst selected from the group consisting of an organic zirconium compound, an organic iron compound, and an organic aluminum compound. ,
The gel fraction is over 40% after being maintained for 300 hours at a temperature of 85°C and a relative humidity of 85%.
An optical laminate having a 180° peel adhesion to PMMA film of at least 100 mN/20 mm. According to claim 20,
An optical laminate wherein the adhesive layer is the following adhesive layer Aa or adhesive layer Ab.
In a creep test using a rotational rheometer, the creep strain rate when a stress of 10,000 Pa was applied for 1 second at 50°C was 10% or less, and the creep strain rate when a stress of 10,000 Pa was applied at 50°C for 30 minutes was 16%. Below,
Adhesive layer Aa, having a 180° peel adhesion to PMMA film of 10 mN/20 mm or more;
An adhesive composition containing a polymer and a curable resin is formed by curing the curable resin,
The initial tensile modulus of elasticity at 23°C before curing the curable resin of the adhesive composition is 0.35 MPa or more and 8.00 MPa or less,
Adhesive layer Ab, wherein the initial tensile modulus of elasticity at 23°C after curing the curable resin of the adhesive composition is 1.00 MPa or more.