JP7242934B2 - optical laminate - Google Patents

Description

TECHNICAL FIELD The present invention relates to an optical laminate including glass plates.

An optical laminate including a glass plate, an adhesive layer, and a triacetyl cellulose film is known (see, for example, Patent Document 1 below). A glass plate has excellent optical properties, but has low impact resistance. Impact resistance is a property of suppressing damage including cracks in a glass sheet when the glass sheet receives an impact.

The optical laminate described in Patent Document 1 is provided in an organic EL display. In the optical laminate described in Patent Document 1, the pencil hardness of the glass plate is measured. Pencil hardness is measured by directly contacting the surface (exposed surface) of a glass plate with a lead of a pencil and evaluating the presence or absence of scratches on the surface. Therefore, when the optical laminate described in Patent Document 1 is provided in an organic EL display, the glass plate is arranged on the viewing side and the triacetyl cellulose film is arranged on the organic EL member side.

JP 2019-25899 A

In recent years, a higher level of impact resistance is required.

Therefore, the inventors of the present application have made intensive studies and found a novel optical laminate in which the second film is arranged on the viewing side of the glass plate and the first film is arranged on the opposite side of the glass plate from the viewing side, It has been found that such an optical layered body has excellent impact resistance.

The present invention (1) comprises a first film, a first adhesive layer, a glass plate, a second adhesive layer, and a second film in order toward one side in the thickness direction, and is the viewing side, and the drop height H1 of the pen until the glass plate starts to crack in the following pen drop crack test is 20 cm or more.
<Pen drop cracking test>
A frequency of 1 Hz, a heating rate of 5° C./min, a temperature of −40° C. to 150° C., a shear storage modulus G′ at 25° C. obtained by a torsion mode dynamic viscoelasticity test is 0.03 MPa, and a thickness is 15 μm. A pressure-sensitive adhesive layer is arranged on the other side in the thickness direction of the optical layered body. A 7 g ballpoint pen with a ball diameter of 0.7 mm is dropped toward the second film. The drop height of the pen is increased by 1 cm up to 30 cm, and the height at which a crack is confirmed on the glass plate is obtained as the height H1 in the pen drop crack test. Alternatively, when no cracks are found in the glass plate when the pen is dropped from a height of 30 cm, it is determined that the glass plate has crack durability of 30 cm or more.

The present invention (2) provides the optical laminate according to (1), wherein the drop height H2 of the pen until the first film or the second film begins to peel in the following pen drop peeling test is 20 cm or more. include.
<Pen drop peeling test>
The pressure-sensitive adhesive layer is arranged on the other side in the thickness direction of the optical layered body. A 7 g ballpoint pen with a ball diameter of 0.7 mm is dropped toward the second film. The drop height of the pen is increased by 1 cm up to 30 cm, and the height at which peeling of the first film or the second film is confirmed is obtained as the height H2 in the pen drop peeling test. Alternatively, when a crack is confirmed in the glass plate, it is determined that the glass plate has peeling durability equal to or greater than the crack height H1.
Alternatively, when peeling is not confirmed in the first film and the second film when the pen is dropped from a height of 30 cm, it is determined that the peeling durability is 30 cm or more.

The present invention (3) is the dynamic The optical laminate according to (1) or (2), wherein the average ratio of tan δ of the second film at −100° C. to −50° C. determined by a viscoelasticity test is 0.8 or more and 1.5 or less. Including body.

In the present invention (4), the average tan δ of the first film at -100 ° C. to -50 ° C. obtained by dynamic viscoelasticity test in tensile mode at a frequency of 10 Hz, a heating rate of 2 ° C./min, is 0.04. Above, the average of the tensile storage modulus E' of the first film at -100 ° C. to -50 ° C. determined by the dynamic viscoelasticity test is 3 GPa or more and 6 GPa or less, (1) to (3 ) includes the optical layered body according to any one of items.

In the present invention (5), the adhesion between the first film and the first adhesive layer is 3.0 kN/m or more, and the adhesion between the first adhesive layer and the glass plate is 3. 0 kN/m or more, the adhesion between the glass plate and the second adhesive layer is 3.0 kN/m or more, and the adhesion between the second adhesive layer and the second film is The optical layered body according to any one of (1) to (4), which is 3.0 kN/m or more.

The present invention (6) includes the optical laminate according to any one of (1) to (5), wherein each of the first film and the second film is a triacetyl cellulose film.

The present invention (7) includes the optical laminate according to (6), wherein the second film is thicker than the first film.

The present invention (8) includes the optical layered body according to (7), further comprising a hard coat layer arranged on one side in the thickness direction of the second film.

The optical laminate of the present invention has excellent impact resistance because the second film is arranged on the viewing side and the drop height H1 of the pen until the glass plate begins to crack in the pen drop crack test is 20 cm or more.

FIG. 1 is a cross-sectional view of one embodiment of the optical laminate of the present invention. 2A to 2C are explanatory diagrams of a method for measuring adhesion. FIG. 2A shows how the cutting edge of the device cuts into the first film. FIG. 2B is an embodiment in which the cutting edge reaches the interface between the first film and the first adhesive layer to measure their adhesion. FIG. 2C is an embodiment in which the cutting edge reaches the interface between the glass plate and the first adhesive layer to measure their adhesion. FIG. 3 is a cross-sectional view of an organic electroluminescence display provided with the optical layered body shown in FIG.

<Optical laminate 1>
An embodiment of the optical laminate of the present invention will be described with reference to FIGS. 1 to 3. FIG.

This optical layered body 1 has, for example, a flat plate shape extending in the plane direction. The plane direction is orthogonal to the thickness direction of the optical layered body 1 . The optical layered body 1 is arranged on the viewing side (hereinafter simply referred to as the viewing side), which is the side viewed by the user when the organic electroluminescence display device 10 (see FIG. 3) is provided. The optical laminate 1 includes a first film 2, a first adhesive layer 3, a glass plate 4, a second adhesive layer 5, and a second film 6 in order toward one side in the thickness direction.
One side in the thickness direction is the viewing side. The other side in the thickness direction is the side opposite to the viewing side (hereinafter simply referred to as the opposite side).

<First film 2>
The first film 2 extends in the surface direction. The first film 2 forms the other side (reverse side) in the thickness direction of the optical layered body 1 .

The average tan δ of the first film 2 at −100° C. to −50° C. obtained by a dynamic viscoelasticity test in tension mode at a frequency of 10 Hz, a temperature increase rate of 2° C./min, a data acquisition interval of 0.5 min, is, for example, 0. 0.02 or more, preferably 0.04 or more, and for example, 0.20 or less, preferably less than 0.06, more preferably 0.05 or less. If the average tan δ of the first film 2 at −100° C. to −50° C. exceeds the above lower limit, the impact resistance of the optical laminate 1 can be improved. The average tan δ of the first film 2 at −100° C. to −50° C. is an index showing responsiveness when an object collides with the optical layered body 1 at high speed. If the average of tan δ is high, even if an object collides with the glass plate 4 at high speed, the impact received by the glass plate 4 can be sufficiently relieved by the first film 2 and the impact resistance of the optical laminate 1 can be improved. Dynamic viscoelasticity testing is described in a later example.

The average tensile storage modulus E′ of the first film 2 at −100° C. to −50° C. obtained by a dynamic viscoelasticity test in tension mode at a frequency of 10 Hz, a heating rate of 2° C./min, is, for example, 3 GPa or more, It is preferably 4 GPa or more, and is, for example, 10 GPa or less, preferably 6 GPa or less, more preferably 5 GPa or less, still more preferably 4.7 GPa or less. If the average tensile storage modulus E′ of the first film 2 at −100° C. to −50° C. is at least the above lower limit, the impact resistance of the optical laminate 1 can be improved.

Examples of the first film 2 include polyester films and cellulose films. Polyester films include, for example, polyethylene terephthalate film (PET), polybutylene terephthalate (PBT) film, and polyethylene naphthalate (PEN) film. Cellulose films include, for example, acetylcellulose films, specifically triacetylcellulose (TAC) films. As the first film 2, from the viewpoint of increasing the adhesion of the first film 2 to the first adhesive layer 3, a cellulose film is preferred, and a TAC film is more preferred.

The thickness of the first film 2 is not limited. The thickness of the first film 2 is, for example, 10 μm or more, preferably 20 μm or more. If the thickness of the first film 2 is at least the above lower limit, the impact resistance of the optical laminate 1 can be improved. The thickness of the first film 2 is, for example, 200 μm or less, preferably 150 μm or less, more preferably 100 μm or less, even more preferably 80 μm or less, particularly preferably 50 μm or less, most preferably 30 μm or less. , 23 μm or less.

The total light transmittance of the first film 2 is, for example, 40% or more, preferably 50% or more, and is, for example, 99% or less.

<First adhesive layer 3>
The first adhesive layer 3 extends in the planar direction. The first adhesive layer 3 is arranged on one surface of the first film 2 in the thickness direction. Specifically, the first adhesive layer 3 contacts one surface of the first film 2 in the thickness direction. The first adhesive layer 3 is not an adhesive layer (pressure-sensitive adhesive layer) made of an adhesive (pressure-sensitive adhesive), but a cured body of a curable adhesive. Specifically, the first adhesive layer 3 is a cured body of a curable adhesive that undergoes a curing reaction when irradiated with active energy rays or heated.

The curable adhesive is a curable raw material for the first adhesive layer 3, and includes active energy curable and heat curable adhesives, preferably active energy curable adhesives. Specifically, curable adhesives include, for example, acrylic adhesive compositions, epoxy adhesive compositions, and silicone adhesive compositions. compositions.

The epoxy adhesive composition contains an epoxy resin as a main ingredient. Examples of epoxy resins include bifunctional epoxy resins containing two epoxy groups and polyfunctional epoxy resins containing three or more epoxy groups. These can be used alone or in combination of two or more.
A combination of a bifunctional epoxy resin and a polyfunctional epoxy resin is preferred.

Examples of bifunctional epoxy resins include aromatic epoxy resins such as bisphenol-type epoxy resins, novolac-type epoxy resins, naphthalene-type epoxy resins, fluorene-type epoxy resins, triphenylmethane-type epoxy resins, and triepoxypropyl isocyanurate. , nitrogen-containing ring epoxy resins such as hydantoin epoxy resins, aliphatic type epoxy resins, glycidyl ether type epoxy resins, and glycidyl amine type epoxy resins. The bifunctional epoxy resin is preferably an aliphatic epoxy resin. Aliphatic type epoxy resins include aliphatic alicyclic epoxy resins. The epoxy equivalent of the bifunctional epoxy resin is, for example, 100 g/eq. above, preferably 120 g/eq. or more, and, for example, 250 g/eq. Below, preferably 150 g/eq. It is below. The ratio of the bifunctional epoxy resin in the epoxy resin is, for example, 80% by mass or more, preferably 90% by mass or more, and is, for example, 99% by mass or less, preferably 97% by mass or less.

Polyfunctional epoxy resins include, for example, phenol novolak type epoxy resin, cresol novolak type epoxy resin, trishydroxyphenylmethane type epoxy resin, tetraphenylolethane type epoxy resin, dicyclopentadiene type epoxy resin, and trifunctional aliphatic epoxy resin. Trifunctional or more polyfunctional epoxy resins such as. The polyfunctional epoxy resin preferably includes a trifunctional aliphatic epoxy resin. The epoxy equivalent of the polyfunctional epoxy resin is, for example, 130 g/eq. above, preferably 150 g/eq. or more, and, for example, 220 g/eq. Below, preferably 200 g/eq. It is below. The proportion of the polyfunctional epoxy resin in the epoxy resin is, for example, 1% by mass or more, preferably 3% by mass or more, and is, for example, 20% by mass or less, preferably 10% by mass or less.

The proportion of the epoxy resin in the epoxy adhesive composition is, for example, 60% by mass or more, preferably 75% by mass or more, and is, for example, 90% by mass or less, preferably 80% by mass or less.

Commercially available epoxy resins can be used, such as Celoxide 2021P (manufactured by Daicel Chemical Industries, Ltd.) as an aliphatic alicyclic epoxy resin, and EHPE3150 (manufactured by Daicel Chemical Industries, Ltd.) as a trifunctional aliphatic epoxy resin.

Moreover, if the epoxy adhesive composition is of the active energy curable type, it contains a photoacid generator. Examples of photoacid generators include triarylsulfonium salts. A commercially available photoacid generator can be used, and CPI101A (manufactured by San-Aflo Co., Ltd.) is used as a triarylsulfonium salt. The proportion of the photoacid generator in the epoxy adhesive composition is, for example, 1% by mass or more, preferably 10% by mass or more, and is, for example, 30% by mass or less, preferably 20% by mass or less.

Furthermore, the epoxy adhesive composition can contain additives such as oxetane resins and silane coupling agents in appropriate proportions.

Examples of oxetane resins include monofunctional oxetanes such as 3-ethyl-3-oxetanemethanol and 2-ethylhexyloxetane, xylylenebisoxetane, 3-ethyl-3{[(3-ethyloxetane-3-yl ) difunctional oxetanes such as methoxy]methyl}oxetane. A commercial product can be used as the oxetane-based resin, such as Aron oxetane (manufactured by Toagosei Co., Ltd.).

Silane coupling agents include, for example, epoxy group-containing silane coupling agents such as 3-glycidoxypropyltrimethoxysilane. As the silane coupling agent, a commercially available product can be used, such as the KBM series (manufactured by Shin-Etsu Silicone Co., Ltd.).

The thickness of the first adhesive layer 3 is not limited. The thickness of the first adhesive layer 3 is, for example, 0.1 μm or more, and is, for example, 10 μm or less, preferably 5 μm or less, more preferably 3 μm or less.

The total light transmittance of the first adhesive layer 3 is, for example, 80% or more, preferably 85% or more, and is, for example, 99% or less.

The tensile storage modulus E′ of the first adhesive layer 3 at 25° C. is, for example, 1 GPa or more, preferably 2 GPa or more, more preferably 3 GPa or more, still more preferably 4 GPa or more, and for example, 100 GPa. It is below. The tensile storage modulus E′ of the first adhesive layer 3 at 25° C. is obtained by measuring dynamic viscoelasticity in a temperature dispersion mode under conditions of a frequency of 1 Hz and a heating rate of 5° C./min. In addition, the elastic modulus of the first adhesive layer 3 at 25° C. measured by the nanoindenter method is, for example, 1 GPa or more, preferably 2 GPa or more, more preferably 3 GPa or more, and still more preferably 4 GPa or more. , or, for example, 100 GPa or less. The measurement conditions for the nanoindenter method are as follows.

Apparatus: Triboindenter (manufactured by Hysitron Inc.)
Sample size: 10x10mm
Indenter: Concial (spherical indenter: curvature radius 10 μm),
Measurement method: single indentation measurement Measurement temperature: 25°C
Indentation depth of indenter: 100 nm
Temperature: 25°C
Analysis: Oliver Pharr analysis based on load-displacement curves

The adhesive strength between the first film 2 and the first adhesive layer 3 is, for example, 0.5 kN/m or more, preferably 1.5 kN/m or more, more preferably 3.0 kN/m or more, and still more preferably , 3.5 kN/m or more, particularly preferably 4.0 kN/m or more, most preferably 5.0 kN/m or more, and for example 10 kN/m or less. The adhesive strength between the first film 2 and the first adhesive layer 3 is determined by inserting the cutting edge 43 of the blade 42 provided in the device 41 into the interface between the first film 2 and the first adhesive layer 3 as shown in FIG. 2A. , as shown in FIG. 2B, it is obtained as the peel strength when the blade 42 is moved along the surface direction to peel the first film 2 from the first adhesive layer 3 . The details of the method for measuring adhesion will be described later in Examples. If the adhesive strength between the first film 2 and the first adhesive layer 3 is equal to or higher than the lower limit described above, peeling of the first film 2 from the first adhesive layer 3 can be suppressed.

<Glass plate 4>
The glass plate 4 extends in the planar direction. A glass plate 4 is located on the opposite side of the first film 2 to the first adhesive layer 3 . The glass plate 4 is arranged on one surface of the first adhesive layer 3 in the thickness direction.
Specifically, the glass plate 4 contacts one surface of the first adhesive layer 3 in the thickness direction. As a result, the first adhesive layer 3 comes into contact with the other thickness direction surface of the glass plate 4 and the one thickness direction surface of the first film 2 , thereby bonding (bonding) the first film 2 and the glass plate 4 . ing.

The total light transmittance of the glass plate 4 is, for example, 80% or more, preferably 85% or more, and is, for example, 99% or less. The glass plate 4 can be a commercially available product, such as G-leaf series (registered trademark, manufactured by Nippon Electric Glass Co., Ltd.).

The adhesive strength between the glass plate 4 and the first adhesive layer 3 is, for example, 3.0 kN/m or more, preferably 3.5 kN/m or more, more preferably 4.0 kN/m or more, and For example, it is 10 kN/m or less. As shown in FIG. 2C, the adhesion between the glass plate 4 and the first adhesive layer 3 is determined by inserting the cutting edge 43 of the blade 42 provided in the device 41 into the interface between the glass plate 4 and the first adhesive layer 3, and 42 is moved along the plane direction to peel off the first adhesive layer 3 from the glass plate 4 . The details of the method for measuring adhesion will be described later in Examples.

The thickness of the glass plate 4 is not limited. The thickness of the glass plate 4 is, for example, 5 μm or more, preferably 10 μm or more, more preferably 20 μm. The thickness of the glass plate 4 is 100 μm or less, preferably 80 μm or less, more preferably 60 μm or less, and even more preferably 50 μm or less.

<Second adhesive layer 5>
The second adhesive layer 5 extends in the planar direction. The second adhesive layer 5 is arranged on one surface of the glass plate 4 in the thickness direction. Specifically, the second adhesive layer 5 contacts one surface of the glass plate 4 in the thickness direction. The second adhesive layer 5 is not an adhesive layer (pressure-sensitive adhesive layer) made of an adhesive (pressure-sensitive adhesive), but a cured body of a curable adhesive. Specifically, the second adhesive layer 5 is a cured body of a curable adhesive that undergoes a curing reaction upon exposure to active energy rays or heating. The cured raw material, thickness, total light transmittance, tensile storage modulus E′, and elastic modulus measured by the nanoindenter method of the second adhesive layer 5 are the same as those of the first adhesive layer 3. .

The adhesive strength between the glass plate 4 and the second adhesive layer 5 is, for example, 3.0 kN/m or more, preferably 3.5 kN/m or more, more preferably 4.0 kN/m or more, and For example, it is 10 kN/m or less. The adhesive strength between the glass plate 4 and the second adhesive layer 5 is obtained by the same method as the method for measuring the adhesive strength between the glass plate 4 and the first adhesive layer 3 described above.

<Second film 6>
The second film 6 forms one surface (visible side surface) in the thickness direction of the optical layered body 1 . A second film 6 is located on the opposite side of the glass plate 4 to the second adhesive layer 5 . The second film 6 extends in the planar direction. The second film 6 is arranged on one surface of the second adhesive layer 5 in the thickness direction. The second film 6 is in contact with one surface of the second adhesive layer 5 in the thickness direction. As a result, the second adhesive layer 5 comes into contact with one surface of the glass plate 4 in the thickness direction and the other surface of the second film 6 in the thickness direction, and adheres (bonds) the glass plate 4 and the second film 6 together. ing.

The average tan δ of the second film 6 at −100° C. to −50° C. obtained by a dynamic viscoelasticity test in tension mode at a frequency of 10 Hz, a temperature increase rate of 2° C./min, a data acquisition interval of 0.5 min. It is set so that the ratio to the average of tan δ of 1 film 2 is within a specific range. The average tan δ of the second film 6 at −100° C. to −50° C. is, for example, 0.02 or more, preferably 0.04 or more, and, for example, 0.20 or less, preferably 0.06. less than, more preferably 0.05 or less. If the average tan δ of the second film 6 at −100° C. to −50° C. exceeds the above lower limit, the impact resistance of the optical laminate 1 can be improved. The average tan δ of the second film 6 at −100° C. to −50° C. is an index showing responsiveness when an object collides with the optical layered body 1 at high speed. If the average of tan δ is high, even if an object collides with the glass plate 4 at high speed, the second film 6 can sufficiently absorb the impact received by the glass plate 4 and the impact resistance of the optical laminate 1 can be improved. Dynamic viscoelasticity testing is described in a later example.

The ratio of the average tan δ of the second film from -100°C to -50°C to the average tan δ of the first film from -100°C to -50°C is, for example, 0.5 or more, preferably 0.8 or more. , more preferably 0.9 or more, and for example, 2.0 or less, preferably 1.5 or less, more preferably 1.1 or less. If the ratio is between the lower limit and the upper limit, the impact resistance of the optical layered body 1 can be improved.

The average tensile storage modulus E′ of the second film 6 at −100° C. to −50° C. obtained by a dynamic viscoelasticity test in tension mode at a frequency of 10 Hz, a heating rate of 2° C./min, is, for example, 3 GPa or more, It is preferably 4 GPa or more, and is, for example, 10 GPa or less, preferably 6 GPa or less, more preferably 5 GPa or less, still more preferably 4.7 GPa or less. If the average tensile storage modulus E′ of the second film 6 at −100° C. to −50° C. is at least the above lower limit, the impact resistance of the optical laminate 1 can be improved.

The adhesive strength between the second film 6 and the second adhesive layer 5 is, for example, 0.5 kN/m or more, preferably 1.5 kN/m or more, more preferably 3.0 kN/m or more, and still more preferably , 3.5 kN/m or more, particularly preferably 4.0 kN/m or more, most preferably 5.0 kN/m or more, and for example 10 kN/m or less. If the adhesive strength between the second film 6 and the second adhesive layer 5 is equal to or higher than the lower limit described above, when an object collides with the second film 6 of the optical laminate 1, the second film 6 and the second adhesive Delamination at the interface with the layer 5 can be suppressed. The adhesive strength between the second film 6 and the second adhesive layer 5 is obtained by the same method as the method for measuring the adhesive strength between the first film 2 and the first adhesive layer 3 described above.

Examples of the second film 6 include the films exemplified for the first film 2 . The second film 6 is preferably , a cellulose film, and more preferably a TAC film.

As the combination of the first film 2 and the second film 6, preferably, the first film 2 is a PET film and the second film 6 is a TAC film, the first film 2 is a TAC film, and the second film Combinations in which 6 is a TAC film are included.
More preferably, a combination in which the first film 2 is a TAC film and the second film 6 is a TAC film, that is, a combination in which each of the first film 2 and the second film 6 is a TAC film.

The thickness of the second film 6 is not limited. Preferably the second film 6 is thicker than the first film 2 . In particular, the second film 6 is thicker than the first film 2 if each of the first film 2 and the second film 6 is a TAC film. If the second film 6 is thicker than the first film 2, it is possible to suppress peeling of the second film 6 while improving the impact resistance of the optical layered body 1.

Specifically, the thickness of the second film 6 is, for example, 10 μm or more, preferably 20 μm or more, more preferably 30 μm or more. If the thickness of the second film 6 is at least the lower limit described above, the impact resistance of the optical laminate 1 can be improved. Also, the thickness of the second film 6 is, for example, 200 μm or less, preferably 100 μm or less, more preferably 60 μm or less. When the thickness of the second film 6 is equal to or less than the upper limit described above, peeling of the second film 6 when an object collides with the optical layered body 1 can be suppressed.

The total light transmittance of the second film 6 is, for example, 80% or more, preferably 85% or more, and is, for example, 99% or less.

<Adhesive layer 12>
The optical layered body 1 may further include an adhesive layer 12 indicated by phantom lines. The adhesive layer 12 is arranged on the other side in the thickness direction of the first film 2 . Specifically, the adhesive layer 12 is in contact with the other thickness direction side of the first film 2 . That is, the optical laminate 1 includes the pressure-sensitive adhesive layer 12, the first film 2, the first adhesive layer 3, the glass plate 4, the second adhesive layer 5, and the second film 6 in the thickness direction. Prepare in order towards one side. The pressure-sensitive adhesive layer 12 is a pressure-sensitive adhesive that does not involve a curing reaction.

The material of the adhesive layer 12 is not limited. Materials for the adhesive layer 12 include, for example, acrylic adhesives, rubber adhesives, vinyl alkyl ether adhesives, silicone adhesives, polyester adhesives, polyamide adhesives, urethane adhesives, and fluorine adhesives. Adhesives, epoxy-based adhesives, and polyether-based adhesives can be mentioned. The material preferably includes an acrylic pressure-sensitive adhesive. The formulation and physical properties of the pressure-sensitive adhesive layer 12 are detailed, for example, in JP-A-2018-28573.

The shear storage elastic modulus G' of the pressure-sensitive adhesive layer 12 at 25°C is, for example, 0.01 MPa or more and, for example, 0.20 MPa or less. The shear storage modulus G' is determined by a dynamic viscoelasticity test in a shear (twist) mode at a frequency of 1 Hz and a heating rate of 5°C/min.

The thickness of the adhesive layer 12 is, for example, 5 μm or more, preferably 5 μm or more, and is, for example, 50 μm or less, preferably 30 μm or less, more preferably 20 μm or less.

The thickness of the optical laminate 1 is, for example, 50 μm or more and, for example, 300 μm or less.

<Pen drop cracking test>
In the optical laminate 1, the drop height H1 of the pen until the glass plate 4 starts to crack in the pen drop crack test is 20 cm or more.

First, the optical layered body 1 is placed on the surface of a horizontal table (not shown) via a resin film 34 indicated by phantom lines. An optical layered body 1 having a thickness of 15 μm is placed on one surface of a glass plate 4 in the thickness direction.
The pressure-sensitive adhesive layer 12 also serves as a fixing member for fixing the optical layered body 1 to a horizontal table in the pen-drop cracking test. The shear storage modulus G' at 25°C obtained by a torsion mode dynamic viscoelasticity test at a frequency of 1 Hz, a heating rate of 5°C/min, and a temperature of -40°C to 150°C is 0.03 MPa.

As shown in FIG. 1 , a pen 29 (Pentel ballpoint pen BK407 black, ball diameter 0.7 mm) is dropped toward the second film 6 . The mass of pen 29 is 7 g. The height from the second film 6 to the tip 32 of the pen 29 is 5 cm. The tip 32 points downward and is sharp. If the glass plate 4 does not crack due to the dropping of the pen 29, the height is raised by 1 cm. The height at which a crack is confirmed in the glass plate 4 is obtained as the height H1 in the pen drop crack test. Alternatively, if no cracks are found in the glass plate 4 when the pen is dropped from a height of 30 cm, it is judged to have a peeling durability of 30 cm or more.

On the other hand, if the drop height H1 in the pen drop cracking test is less than 20 cm, the impact resistance of the optical laminate 1 is low.

On the other hand, the drop height H1 in the pen drop crack test is preferably 25 cm or more, more preferably 30 cm or more.

<Pen drop peeling test>
In the optical layered body 1, the dropping height H2 of the pen 29 until the second film 6 starts peeling in the pen drop peeling test is 20 cm or more.

The pen drop peel test is performed in parallel with the pen drop crack test described above. First, the optical layered body 1 is placed on the surface of a horizontal table (not shown) via a resin film 34 indicated by phantom lines. When the adhesive layer 12 is not arranged on the optical laminate 1, the same adhesive layer 12 as the adhesive layer 12 used in the pen-drop cracking test is arranged on one side of the optical laminate 1 in the thickness direction.

As shown in FIG. 1 , a pen 29 (Pentel ballpoint pen BK407 black, ball diameter 0.7 mm) is dropped toward the second film 6 . The mass of pen 29 is 7 g. The height from the glass plate 4 to the tip 32 of the pen 29 is 5 cm. The tip 32 points downward and is sharp. By dropping the pen 29 as described above, the first film 2 is peeled off from the first adhesive layer 3, the glass plate 4 is peeled off from the first adhesive layer 3, and the glass plate 4 is peeled off from the second adhesive layer 5. , and if the peeling of the second film 6 from the second adhesive layer 5 does not occur, the height is raised by 1 cm. The height at which any of the above peeling can be confirmed is obtained as the height H2 in the pen drop peeling test. Alternatively, when a crack is confirmed in the glass plate 4, it is determined that the glass plate 4 has peeling durability equal to or greater than the crack height H1. Alternatively, when the above-described peeling is not confirmed when the pen is dropped from a height of 30 cm, it is determined that the peeling durability is 30 cm or more.

The optical laminate 1 that satisfies the above requirements has the adhesion strength of the first film 2 to the first adhesive layer 3, the adhesion strength of the glass plate 4 to the first adhesive layer 3, and the adhesion strength of the second adhesive layer 5 to the glass plate 4. and the adhesion of the second film 6 to the second adhesive layer 5 are high. Therefore, the optical laminate 1 has excellent reliability.

<Manufacturing Method of Optical Layered Body 1>
A method for manufacturing the optical laminate 1 will be described. In the method for manufacturing the optical laminate 1, for example, a curable adhesive is placed (applied) on the other thickness direction surface of the glass plate 4 and/or one thickness direction surface of the first film 2, and the glass plate 4 and the first film In 2, the curable adhesive described above is sandwiched. A curable adhesive is placed (applied) on one side in the thickness direction of the glass plate 4 and/or on the other side in the thickness direction of the second film 6 , and the curable adhesive is sandwiched between the glass plate 4 and the second film 6 .

The two curable adhesives are then cured. If the curable adhesive is of the active energy curable type, the curable adhesive is irradiated with active energy including ultraviolet rays. If the curable adhesive is thermosetting, the curable adhesive is heated. Thereby, the first adhesive layer 3 and the second adhesive layer 5 are formed. The first adhesive layer 3 firmly bonds the first film 2 and the glass plate 4 together. The second adhesive layer 5 firmly bonds the glass plate 4 and the second film 6 together.

As a result, the optical laminate 1 including the first film 2, the first adhesive layer 3, the glass plate 4, the second adhesive layer 5, and the second film 6 is obtained.

After that, in order to further equip the optical layered body 1 with the pressure-sensitive adhesive layer 12 , the pressure-sensitive adhesive layer 12 is arranged on the other side in the thickness direction of the first film 2 . For example, a varnish containing an adhesive is applied to the other surface of the first film 2 in the thickness direction and dried. Alternatively, the pressure-sensitive adhesive layer 12 formed on a release sheet (not shown) can be transferred to the other surface of the first film 2 in the thickness direction. As a result, an optical laminate 1 including the adhesive layer 12, the first film 2, the first adhesive layer 3, the glass plate 4, the second adhesive layer 5, and the second film 6 is obtained. Note that the optical layered body 1 may be provided with a release sheet (not shown). In that case, the optical laminate 1 includes a release sheet (not shown), an adhesive layer 12, a first film 2, a first adhesive layer 3, a glass plate 4, a second adhesive layer 5, and a second film 6 .

<Application of Optical Laminate 1>
The optical layered body 1 is used for various optical applications, and is provided in an image display device, for example. Examples of image display devices include organic electroluminescence display devices (hereinafter simply referred to as “organic EL display devices”).

Next, an organic EL display device 10 including the optical layered body 1 will be described with reference to FIG.

<Organic EL display device 10>
The organic EL display device 10 has a flat plate shape extending in the plane direction. Since the organic EL display device 10 includes the conductive film 13 described below, it functions as a touch panel type input display device. The organic EL display device 10 includes an optical laminate 1, a conductive film 13, a second pressure-sensitive adhesive layer 14, and an image display member 15 in order toward the front side. In the organic EL display device 10, the upper side of the paper surface is the user's viewing side and the front side (corresponding to the other thickness direction side in FIG. 1), and the lower side of the paper surface is the back side (one thickness direction side in FIG. 1). ).

<Optical laminate 1>
The optical laminate 1 includes an adhesive layer 12, a first film 2, a first adhesive layer 3, a glass plate 4, a second adhesive layer 5, and a second film 6 on the front side (visible side). Prepare in order.

<Conductive film 13>
The conductive film 13 has a conductive layer 16 and a substrate layer 17 in order toward the back side.

<Conductive layer 16>
The conductive layer 16 has a predetermined pattern. The surface and side surfaces of the conductive layer 16 are in contact with the adhesive layer 12 . Examples of materials for the conductive layer 16 include metal oxides, conductive fibers (fibers), and metals. Metal oxides include composite oxides. Examples of composite oxides include indium zinc composite oxide (IZO), indium gallium zinc composite oxide (IGZO), indium gallium composite oxide (IGO), indium tin composite oxide (ITO), and antimony tin composite oxide. An oxide (ATO) can be mentioned. Conductive fibers include, for example, metal nanowires and carbon nanotubes. Metals include, for example, gold, platinum, silver, and copper. The conductive layer 16 integrally has a sensor electrode portion 18 located in the central portion in the plane direction and a lead wire portion 19 located around the sensor electrode portion 18 . Details of the conductive layer 16 are described, for example, in JP-A-2017-102443, JP-A-2014-113705, and JP-A-2014-219667.

<Base material layer 17>
The base material layer 17 is arranged on the back surface of the conductive layer 16 and the back surface of the adhesive layer 12 . The base material layer 17 extends in the surface direction. The base material layer 17 is, for example, a resin layer. Materials for the base material layer 17 include olefin resin, polyester resin, (meth)acrylic resin, polycarbonate resin, polyethersulfone resin, polyarylate resin, melamine resin, polyamide resin, polyimide resin, cellulose resin, and polystyrene resin. mentioned. Olefin resins include, for example, polyethylene, polypropylene, and cycloolefin polymers (COP). Polyester resins include, for example, PET, PBT, and PEN. (Meth)acrylic resins include, for example, poly(meth)acrylate resins. Details of the base material layer 17 are described, for example, in Japanese Unexamined Patent Application Publication No. 2018-181722.

<Second adhesive layer 14>
The second adhesive layer 14 is arranged on the back surface of the conductive film 13 . Specifically, the second adhesive layer 14 is in contact with the back surface of the conductive film 13 . The material for the second adhesive layer 14 is the same as the material for the adhesive layer 12 .

<Image display member 15>
The image display member 15 forms the back surface of the organic EL display device 10 . The image display member 15 is arranged on the back side of the conductive film 13 with the second adhesive layer 14 interposed therebetween. The image display member 15 extends in the planar direction. Specifically, the image display member 15 is an organic EL element. For example, although not shown, the image display member 15 includes a display substrate, two electrodes, an organic EL layer sandwiched between the two electrodes, and a sealing layer. The configuration and physical properties of the image display member 15 are detailed in, for example, JP-A-2018-28573.

<Action and effect of one embodiment>
The optical laminate 1 of one embodiment has a novel configuration in which the second film 6 is arranged on the viewing side of the glass plate 4 and the first film 2 is arranged on the opposite side of the glass plate 4 . In the optical layered body 1, the drop height H1 of the pen until the glass plate 4 starts to crack in the pen drop crack test is 20 cm or more. Therefore, the optical layered body 1 is excellent in impact resistance.

In the optical layered body 1, preferably, in the pen drop peeling test, the drop height H2 of the pen until the first film 2 or the second film 6 starts peeling is 20 cm or more. Therefore, the optical laminate 1 has excellent reliability.

In addition, in the optical laminate 1, the ratio of the average tan δ of the first film 2 from -100°C to -50°C to the average tan δ of the second film 6 from -100°C to -50°C is 0.8 or more. , 1.5 or less, the difference in impact absorption behavior between the first film 2 and the second film 6 can be reduced. Therefore, peeling of the first film 2 or the second film 6 can be suppressed. As a result, the optical laminate 1 has excellent reliability.

In addition, in this optical layered body 1, the average tan δ of the first film 2 from -100°C to -50°C is 0.04 or more, When the average tensile storage modulus E′ of the first film 2 is 3 GPa or more and 6 GPa or less, cracking of the glass plate 4 in the pen drop crack test can be suppressed. Therefore, the optical layered body 1 is excellent in impact resistance.

Further, in this optical laminate 1, the adhesion between the first film 2 and the first adhesive layer 3 is 3.0 kN/m or more, and the adhesion between the first adhesive layer 3 and the glass plate 4 is 3.0 kN/m. 0 kN/m or more, the adhesion between the glass plate 4 and the second adhesive layer 5 is 3.0 kN/m or more, and the adhesion between the second adhesive layer 5 and the second film 6 is 3.0 kN/m or more. If it is 0 kN/m or more, the adhesion of the first film 2 to the glass plate 4 and the adhesion of the second film 6 to the glass plate 4 are excellent. Therefore, the optical laminate 1 has excellent reliability.

Further, in the optical laminate 1, if each of the first film 2 and the second film 6 is a TAC film, the adhesion of the first film 2 to the first adhesive layer 3 and the second film 6 has excellent adhesion to the second adhesive layer 5. Therefore, the optical laminate 1 has excellent reliability.

Also, if the second film 6 is thicker than the first film 2, the resistance of the first film 2 to the impact absorption behavior of the second film 6 can be reduced. 2, peeling of the film 6 can be suppressed. Therefore, the optical laminate 1 has excellent reliability.

<Modification>
In the following modified examples, the same reference numerals are given to the same members and steps as in the above-described embodiment, and detailed description thereof will be omitted. In addition, the modified example can have the same effects as the one embodiment, unless otherwise specified.

In one embodiment, the first film 2 is a single layer, but the number of layers of the first film 2 is not limited. The first film 2 may be multi-layered.

In one embodiment, the second film 6 is a single layer, but the number of layers of the second film 6 is not limited. The second film 6 may be multi-layered.

The optical layered body 1 may further include a hard coat layer 38, as indicated by the dashed line in FIG. The hard coat layer 38 is arranged on one surface of the second film 6 in the thickness direction. The hard coat layer 38 is in contact with one surface of the second film 6 in the thickness direction. The optical laminate 1 includes the first film 2, the first adhesive layer 3, the glass plate 4, the second adhesive layer 5, the second film 6, and the hard coat layer 38 facing the viewer side. Prepare in order. The formulation, physical properties and dimensions of the hard coat layer 38 are not particularly limited. In this modification, since the optical layered body 1 includes the hard coat layer 38, the impact resistance and scratch resistance of the optical layered body 1 can be improved.

Other functional layers may be provided in place of the hard coat layer 38 or additionally. Other functional layers include, for example, anti-scattering layers, anti-fouling layers, and anti-reflection layers. These may be a single layer or multiple layers.

Since the optical laminate of the present invention has excellent impact resistance, even a glass plate having a thickness of less than 40 μm has sufficient impact resistance. Since a glass plate having a thickness of less than 40 μm has excellent flexibility, the optical laminate of the present invention can also be suitably used for flexible displays such as foldable displays and rollable displays.

Specific numerical values such as the mixing ratio (content ratio), physical property values, and parameters used in the following description are described in the above "Mode for Carrying Out the Invention", the corresponding mixing ratio (content ratio ), physical properties, parameters, etc. can. In the description below, "parts" and "%" are based on mass unless otherwise specified.

In the following examples and comparative examples, the optical layered body 1 was produced, the pressure-sensitive adhesive layer 12 was placed on the optical layered body 1, and the impact resistance and peeling resistance of the optical layered body 1 were evaluated.

Example 1
A glass plate 4 (G-leaf) with a thickness of 30 μm, a first film 2 (Diafoil S100, manufactured by Mitsubishi Chemical Corporation) made of a polyethylene terephthalate film with a thickness of 25 μm, and a triacetyl cellulose film with a thickness of 40 μm (KC4UYW, manufactured by Konica Minolta ) was prepared. In addition, aliphatic alicyclic epoxy resin (Celoxide 2021P, epoxy equivalent 128 to 133 g / eq., manufactured by Daicel Chemical Industries, Ltd.) 70 parts by mass, trifunctional aliphatic epoxy resin (EHPE3150, epoxy equivalent 170 to 190 g / eq., Daicel Chemical Co., Ltd.) 5 parts by mass, oxetane resin (Aron oxetane, Toagosei Co., Ltd.) 19 parts by mass, silane coupling agent (KBM-403, 3-glycidoxypropyltrimethoxysilane, Shin-Etsu Chemical Co., Ltd.) 4 Parts by mass and 2 parts by mass of a photoacid generator (CPI101A, triarylsulfonium salt, manufactured by San-Aflo Co., Ltd.) were blended to prepare an epoxy adhesive composition. This epoxy adhesive composition was sandwiched between the glass plate 4 and the first film 2 . The epoxy adhesive composition applied to one surface of the glass plate 4 was sandwiched between the glass plate 4 and the second film 6 .

After that, the two curable adhesives were irradiated with ultraviolet light. Thus, a first adhesive layer 3 with a thickness of 1 μm and a second adhesive layer 5 with a thickness of 1 μm were formed. The first adhesive layer 3 is made of a cured material that firmly bonds the first film 2 and the glass plate 4 together. The elastic modulus of the first adhesive layer 3 at 25° C. measured by the nanoindenter method was 4.9 GPa. The second adhesive layer 5 is made of a cured material that firmly bonds the second film 6 and the glass plate 4 together. The elastic modulus of the second adhesive layer 5 at 25° C. measured by the nanoindenter method was 4.9 GPa.

As a result, the optical layered body 1 including the first film 2, the first adhesive layer 3, the glass plate 4, the second adhesive layer 5, and the second film 6 in order toward one side in the thickness direction is obtained. manufactured.

Next, a pressure-sensitive adhesive layer 12 having a thickness of 15 μm was placed on the other side of the first film 2 in the thickness direction by transfer. Adhesive layer 12 was prepared as follows.

Lauryl acrylate (LA) 43 parts by mass, 2-ethylhexyl acrylate (2EHA) 44 parts by mass, 4-hydroxybutyl acrylate (4HBA) 6 parts by mass, N-vinyl-2-pyrrolidone (NVP) 7 parts by mass, and manufactured by BASF 0.015 part by mass of "Irgacure 184" was blended and polymerized by irradiation with ultraviolet rays to obtain a base polymer composition (polymerization rate: about 10%).

Separately, 60 parts by mass of dicyclopentanyl methacrylate (DCPMA), 40 parts by mass of methyl methacrylate (MMA), 3.5 parts by mass of α-thioglycerol, and 100 parts by mass of toluene were mixed and mixed under a nitrogen atmosphere. Stir at 70° C. for 1 hour. Next, 0.2 parts by mass of 2,2'-azobisisobutyronitrile (AIBN) was added and reacted at 70°C for 2 hours, then heated to 80°C and reacted for 2 hours. After that, the reaction solution was heated to 130° C. to remove the toluene, the chain transfer agent and the unreacted monomer by drying to obtain a solid acrylic oligomer. The acrylic oligomer had a weight average molecular weight of 5,100. The glass transition temperature (Tg) was 130°C.

Based on 100 parts by mass of solid content of the base polymer composition, 0.07 parts by mass of 1,6-hexanediol diacrylate (HDDA), 1 part by mass of acrylic oligomer, silane coupling agent (manufactured by Shin-Etsu Chemical "KBM403") After adding 0.3 parts by mass, they were uniformly mixed to prepare an adhesive composition.

The pressure-sensitive adhesive composition is applied to the surface of a release sheet made of a PET film (“Diafoil MRF75” manufactured by Mitsubishi Chemical), and then another release sheet made of a PET film (“Diafoil MRF75” manufactured by Mitsubishi Chemical) is applied. glued to the membrane. After that, the coating film was irradiated with ultraviolet rays to prepare a pressure-sensitive adhesive layer 12 having a thickness of 15 μm. The shear storage modulus G' of this adhesive layer 12 at 25°C was 0.03 MPa. The measuring method is as follows.
The pressure-sensitive adhesive layer 12 is processed into a disk shape, sandwiched between parallel plates, and subjected to dynamic viscoelasticity measurement under the following conditions using Rheometric Scientific's "Advanced Rheometric Expansion System (ARES)" to measure the pressure-sensitive adhesive layer 12. A shear storage modulus G' at 25°C was determined.

[conditions]
Mode: Torsion Temperature: -40°C to 150°C
Heating rate: 5°C/min Frequency: 1Hz

Example 2
An optical laminate 1 was produced in the same manner as in Example 1. However, the thickness of the first film 2 was changed to 50 μm.

Example 3
An optical laminate 1 was produced in the same manner as in Example 2. However, the second film 6 was changed to a 20 μm-thick triacetyl cellulose film (KC2CT, manufactured by Konica Minolta).

Example 4
An optical laminate 1 was produced in the same manner as in Example 1. However, the second film 6 was changed to a 20 μm-thick triacetyl cellulose film (KC2CT, manufactured by Konica Minolta).

Example 5
An optical laminate 1 was produced in the same manner as in Example 3. However, the first film 2 was changed to a 40 μm-thick triacetyl cellulose film (KC4UYW, manufactured by Konica Minolta).

Example 6
An optical laminate 1 was produced in the same manner as in Example 1. However, the first film 2 was changed to a 20 μm-thick triacetyl cellulose film (KC2CT, manufactured by Konica Minolta).

Example 7
An optical laminate 1 was produced in the same manner as in Example 5. However, the first film 2 was changed to a 20 μm-thick triacetyl cellulose film (KC2CT, manufactured by Konica Minolta).

Comparative example 1
An optical laminate 1 was produced in the same manner as in Example 3. However, the optical laminate 1 was not provided with the first film 2 and the first adhesive layer 3 . This optical laminate 1 comprises a glass plate 4 , a second adhesive layer 5 and a second film 6 .

Comparative example 2
An optical laminate 1 was produced in the same manner as in Example 5. However, the optical laminate 1 was not provided with the second adhesive layer 5 and the second film 6 . This optical laminate 1 comprises a first film 2 , a first adhesive layer 3 and a glass plate 4 .

Table 1 lists the types and thicknesses of the first film 2 and the second film 6 in each example and comparative example.

<Evaluation>
The following items were measured and evaluated for each example and comparative example. The results are listed in Table 1.

<tan δ and tensile storage modulus E′ of first film 2 and second film 6>
The first film 2 and the second film 6 prepared in each example and comparative example were subjected to a dynamic viscoelasticity test. Equipment and conditions are described below.

Apparatus: Multifunctional dynamic viscoelasticity measuring apparatus DMS6100 manufactured by Hitachi High-Tech Science Co., Ltd.
Temperature range: -100 to 200°C
Heating rate: 2°C/min
Mode: Tensile Sample width: 10mm
Distance between chucks: 20mm
Frequency: 10Hz
Strain amplitude: 10 μm
Atmosphere: Air (250 ml/min)
Data acquisition interval: 0.5 min (every 1°C)

Each average of the tensile storage modulus E' of the first film 2 at -100°C to -50°C is obtained by dividing the sum of all the data obtained above at -100°C to -50°C by the number of data, Calculated. Each average of tan δ of the first film 2 from -100°C to -50°C was calculated by dividing the sum of all the data obtained above from -100°C to -50°C by the number of data. The average tan δ of the second film 6 was also calculated in the same manner as above.

<Adhesion Strength Between First Film 2 and First Adhesive Layer 3 and Adhesion Strength Between Second Film 6 and Second Adhesive Layer 5>
Using a surface/interface property analyzer, the adhesion between the first film 2 and the first adhesive layer 3 was measured according to the following apparatus, conditions and method.

Apparatus: Surface/interface physical property analyzer (SAICAS DN-20 type) manufactured by Daipla Wintes Co., Ltd.

Material of blade 42: Single crystal diamond Width of blade edge 43: 1 mm
Rake angle of cutting edge 43: 10°

As shown in FIG. 2A, the surface/interface physical property analysis device 41 includes a blade 42, and a moving device and a pressure measuring section (not shown). Blade 42 is movable. The blade 42 has a cutting edge 43 formed at the tip.

As shown in FIG. 2A, the optical layered body 1 was set in the measuring device 41 .

The cutting edge 43 was moved in the horizontal direction (corresponding to the surface direction of the optical laminate 1) obliquely to one side in the thickness direction. The horizontal velocity is 10 μm/sec and the vertical velocity is 0.5 μm/sec.
As a result, the cutting edge 43 cuts into the first film 2 .

As shown in FIG. 2B, when the cutting edge 43 reached the interface between the first film 2 and the first adhesive layer 3, the cutting edge 43 was moved only in the horizontal direction. The horizontal velocity remains at 10 μm/sec. The first film 2 was peeled from the first adhesive layer 3 by the horizontal movement of the cutting edge 43 . The peel strength at this time was measured as the adhesive strength between the first films 2 and 3 .

The adhesion between the second film 6 and the second adhesive layer 5 was obtained in the same manner as above.

<Adhesion between the first adhesive layer 3 and the glass plate 4 and adhesion between the glass plate 4 and the second adhesive layer 5>
The adhesion between the first adhesive layer 3 and the glass plate 4 was measured using the same apparatus, conditions and method as above. However, as shown in FIG. 2C, after the cutting edge 43 cuts into the first film 2, it also cuts into the first adhesive layer 3, and the cutting edge 43 reaches the interface between the first adhesive layer 3 and the glass plate 4. Sometimes, the cutting edge 43 was moved horizontally. As a result, the first adhesive layer 3 was separated from the glass plate 4 . The peel strength at this time was measured as the adhesive strength between the first adhesive layer 3 and the glass plate 4 . The adhesion force between the first adhesive layer 3 and the glass plate 4 was 4.5 kN/m.

The adhesive strength between the glass plate 4 and the second adhesive layer 5 was obtained in the same manner as described above. The adhesion force between the glass plate 4 and the second adhesive layer 5 was 4.5 kN/m.

<Pen drop cracking test>
The following pen-drop cracking test was performed on the optical laminates 1 of each example and comparative example. First, as shown in FIG. 1, the optical laminate 1 was placed on the surface of the resin film 34 (phantom line) so that the second film 6 faced upward. Specifically, the adhesive layer 12 was attached to the surface of the resin film 34 . The resin film 34 is Prescale (manufactured by Fuji Film, Prescale MS medium-pressure mono-sheet type, thickness 95 μm). The resin film 34 is arranged on the surface of a horizontal table (not shown). Next, a pen drop cracking test is performed by dropping a 7 g ball-point pen 29 having a ball diameter of 0.7 mm from a height of 5 cm from the second film 6 . The above height of 5 cm is the distance between one surface of the second film 6 in the thickness direction and the tip 32 of the pen 29 . The tip 32 points downward and is sharp. In this optical laminate 1, if the pen 29 is dropped as described above and the glass plate 4 is cracked, the height H1 in the pen drop crack test is 5 cm. If the glass plate 4 does not crack, the height is raised by 1 cm. Thereby, the height H1 when the glass plate 4 is cracked is obtained.

<Pen drop peeling test>
The pen 29 was dropped onto the second film 6 in the same manner as the pen drop cracking test described above. The initial drop height was set at 5 cm. Thereafter, peeling of the second film 6 from the second adhesive layer 5, peeling of the glass plate 4 from the second adhesive layer 5, peeling of the glass plate 4 from the first adhesive layer 3, or the first film When peeling from the first adhesive layer 3 of 2 did not occur, the height was raised by 1 cm. The height at which the peeling was confirmed was obtained as the height H2 in the pen-drop peeling test. Alternatively, when a crack is confirmed in the glass plate 4, it is determined that the glass plate 4 has peeling durability with a crack height H1 or more. Alternatively, when the above-described peeling was not confirmed even when the pen 29 was dropped from a height of 30 cm, it was determined that "it has peeling durability of 30 cm or more".

1 optical laminate 2 first film 3 first adhesive layer 4 glass plate 5 second adhesive layer 6 second film 12 adhesive layer 29 pen 38 hard coat layer

Claims (8)

A first film, a first adhesive layer, a glass plate, a second adhesive layer, and a second film are provided in order toward one side in the thickness direction,
The one side in the thickness direction is a viewing side,
The drop height H1 of the pen until the glass plate starts to crack in the following pen drop cracking test is 20 cm or more,
Each of the first film and the second film has a thickness of 10 μm or more,
The indentation elastic modulus of each of the first adhesive layer and the second adhesive layer at 25° C. measured by a nanoindenter method is 1 GPa or more,
The glass plate has a thickness of 10 μm or more,
each of the first film and the second film is a polyethylene terephthalate film or a triacetylcellulose film ;
An optical laminate, wherein the first adhesive layer is a cured epoxy resin adhesive composition .
<Pen drop cracking test>
A frequency of 1 Hz, a heating rate of 5° C./min, a temperature of −40° C. to 150° C., and a shear storage modulus G′ at 25° C. obtained by a dynamic viscoelasticity test in torsional mode is 0.03 MPa,
A pressure-sensitive adhesive layer having a thickness of 15 μm is arranged on the other side in the thickness direction of the optical layered body. A 7 g ballpoint pen with a ball diameter of 0.7 mm is dropped toward the second film. The drop height of the pen is increased by 1 cm up to 30 cm, and the height at which a crack is confirmed on the glass plate is obtained as the height H1 in the pen drop crack test. Alternatively, when no cracks are found in the glass plate when the pen is dropped from a height of 30 cm, it is determined that the glass plate has crack durability of 30 cm or more. 2. The optical laminate according to claim 1, wherein the drop height H2 of the pen until the first film or the second film starts to peel in the following pen drop peeling test is 20 cm or more.
<Pen drop peeling test>
The pressure-sensitive adhesive layer is arranged on the other side in the thickness direction of the optical layered body. A 7 g ballpoint pen with a ball diameter of 0.7 mm is dropped toward the second film. The drop height of the pen is increased by 1 cm up to 30 cm, and the height at which peeling of the first film or the second film is confirmed is obtained as the height H2 in the pen drop peeling test. Alternatively, when a crack is confirmed in the glass plate, it is determined that the glass plate has peeling durability equal to or greater than the crack height H1.
Alternatively, when peeling is not confirmed in the first film and the second film when the pen is dropped from a height of 30 cm, it is determined that the peeling durability is 30 cm or more. A frequency of 10 Hz, a heating rate of 2 ° C./min, and a dynamic viscoelasticity test in tension mode for the average tan δ of the first film at -100 ° C to -50 ° C., determined by the dynamic viscoelastic test - 3. The optical laminate according to claim 1, wherein the average ratio of tan δ of the second film at 100° C. to -50° C. is 0.8 or more and 1.5 or less. The average tan δ of the first film at -100 ° C. to -50 ° C. obtained by a dynamic viscoelasticity test in tension mode at a frequency of 10 Hz, a temperature increase rate of 2 ° C./min, is 0.04 or more, and the dynamic The optical according to any one of claims 1 to 3, wherein the average tensile storage modulus E' of the first film at -100°C to -50°C obtained by a viscoelasticity test is 3 GPa or more and 6 GPa or less. laminate. Adhesion between the first film and the first adhesive layer is 3.0 kN/m or more,
Adhesion between the first adhesive layer and the glass plate is 3.0 kN/m or more,
The adhesive strength between the glass plate and the second adhesive layer is 3.0 kN/m or more,
5. The optical laminate according to any one of claims 1 to 4, wherein the adhesive strength between the second adhesive layer and the second film is 3.0 kN/m or more. The optical laminate according to any one of claims 1 to 5, wherein the first film is a triacetylcellulose film. 7. The optical stack of claim 6, wherein said second film is thicker than said first film. Further comprising a hard coat layer arranged on one side in the thickness direction of the second film,
The optical laminate according to any one of claims 1 to 7.

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