CN116547143A

CN116547143A - Optical laminate

Info

Publication number: CN116547143A
Application number: CN202180078668.6A
Authority: CN
Inventors: 矢野孝伸
Original assignee: Nitto Denko Corp
Current assignee: Nitto Denko Corp
Priority date: 2020-11-24
Filing date: 2021-05-18
Publication date: 2023-08-04
Also published as: WO2022113400A1; KR20230111604A; JP7036888B1; TW202220836A; JP2022083325A

Abstract

An optical laminate (1) is provided with a glass plate (2), an adhesive layer (3), and a film (4) in this order toward one side in the thickness direction, and one side in the thickness direction is the visible side. In the pen-down breaking test described below, the pen-down height H1 until the glass plate (2) starts breaking is 15cm or more. [ drop fracture test ] an adhesive layer (12) having a shear storage modulus G' of 0.03MPa and a thickness of 15 [ mu ] m is disposed on the other surface of the optical laminate (1) in the thickness direction. A ball-point pen (29) having a ball diameter of 0.7mm and 7g was dropped onto the film (4), and the drop height of the pen was gradually increased to obtain a height H1 in the drop pen breaking test, which was a height at which breakage was confirmed in the glass plate (2).

Description

Optical laminate

Technical Field

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

Background

An optical laminate including a glass plate, an adhesive layer, and a cellulose triacetate film is known (for example, refer to patent document 1 below). The glass plate is excellent in optical characteristics, while on the other hand, impact resistance is low. Impact resistance is a property that suppresses damage including cracks in a glass sheet when the glass sheet is impacted.

The optical laminate described in patent document 1 can be provided in an organic EL display. For the optical laminate described in patent document 1, pencil hardness of the glass plate can be measured. The pencil hardness was measured by directly contacting the lead of the pencil with the surface (exposed surface) of the glass plate and evaluating the presence or absence of damage to 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 visible side, and the cellulose triacetate film is arranged on the organic EL member side.

Prior art literature

Patent literature

Patent document 1: japanese patent laid-open publication No. 2019-25899

Disclosure of Invention

Problems to be solved by the invention

In recent years, a higher level of impact resistance has been demanded.

Means for solving the problems

Accordingly, the present inventors have conducted intensive studies and as a result, have found a novel optical laminate in which a film is disposed on the visible side, and have found that such an optical laminate is excellent in impact resistance.

The invention (1) comprises an optical laminate comprising a glass plate, an adhesive layer and a film in this order toward one side in the thickness direction,

one side in the thickness direction is a visible side,

in the pen-down breaking test described below, the pen-down height H1 until the glass plate starts breaking was 15cm or more.

< test of break in pen >)

An adhesive layer was disposed on the other surface of the optical laminate in the thickness direction, a ball-point pen having a ball diameter of 0.7mm and 7G was dropped onto the film, the drop height of the pen was increased by 1cm each time, the height at which breakage was confirmed in the glass plate was obtained as a height H1 in the drop breakage test, the thickness of the adhesive layer was 15 μm, and the shear storage modulus G' at 25℃was 0.03MPa as determined by the dynamic viscoelasticity test at a frequency of 1Hz, a heating rate of 5 ℃/min, a temperature of-40℃to 150℃and a torsion mode.

The invention (2) includes the optical laminate according to (1), wherein,

in the pen-down peeling test described below, the pen-down height H2 until the film starts peeling was 15cm or more,

< Pen-drop peel test >)

The pressure-sensitive adhesive layer was disposed on the other surface of the optical laminate in the thickness direction, a ballpoint pen having a ball diameter of 0.7mm and 7g was dropped onto the film, and the drop height of the pen was gradually increased to 30cm, and the height at which peeling of the film was confirmed was obtained as a height H2 in the drop peeling test, or when the glass plate was broken, it was determined that the film had peeling durability equal to or higher than the breaking height H1.

The invention (3) includes the optical laminate according to (1) or (2), wherein,

the average value of tan delta of the film at-100 ℃ to-50 ℃ obtained by a dynamic viscoelasticity test of a frequency of 10Hz, a heating rate of 2 ℃/min and a stretching mode is more than 0.04, and the average value of the tensile storage modulus E' of the film at-100 ℃ to-50 ℃ obtained by the dynamic viscoelasticity test is more than 3GPa and less than 6 GPa.

The invention (4) includes the optical laminate according to any one of (1) to (3), wherein,

the adhesion force between the glass plate and the adhesive layer is 3.0kN/m or more,

the adhesive force between the film and the adhesive layer is 3.0kN/m or more.

The invention (5) includes the optical laminate according to any one of claims (1) to (4), wherein,

the above film is cellulose triacetate film.

The invention (6) includes the optical laminate according to (5), wherein,

the film has a thickness of 10 μm or more and 60 μm or less.

The invention (7) further comprises the optical laminate according to any one of claims (1) to (6), further comprising a hard coat layer disposed on one surface of the film in the thickness direction.

ADVANTAGEOUS EFFECTS OF INVENTION

The optical laminate of the present invention has a film disposed on the visible side, and has excellent impact resistance because the drop height H1 of the pen is 15cm or more until the glass plate starts to fracture in the pen breakage test.

Drawings

Fig. 1 is a cross-sectional view of one embodiment of an optical stack of the present invention.

Fig. 2A to 2C are explanatory views of a method for measuring the adhesion force. Fig. 2A shows a mode in which the edge of the device is cut into the film. Fig. 2B shows a mode in which the edge reaches the interface between the film and the adhesive layer and the adhesion force between them is measured. Fig. 2C shows a mode in which the edge reaches the interface between the glass plate and the adhesive layer and the adhesion force between them is measured.

Fig. 3 is a cross-sectional view of an organic electroluminescent display device including the optical layered body shown in fig. 1.

Symbol description

1. Optical laminate

2. Glass plate

3. Adhesive layer

4. Film and method for producing the same

29. Pen with pen tip

38. Hard coat layer

Detailed Description

< optical laminate 1 >)

An embodiment of the optical laminate of the present invention will be described with reference to fig. 1 to 3.

The optical laminate 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 laminate 1. When the optical laminate 1 is provided in the organic electroluminescent display device 10 (see fig. 3), it is arranged on the visual side (hereinafter, simply referred to as the visual side) which is the side to be visually recognized by the user. The optical laminate 1 includes a glass plate 2, an adhesive layer 3, and a film 4 in this order toward one side in the thickness direction. One side in the thickness direction is a visible side. The other side in the thickness direction is the opposite side to the visible side (hereinafter simply referred to as opposite side).

< glass plate 2 >)

The glass plate 2 extends in the plane direction. The glass plate 2 forms the other surface (opposite side surface) of the optical laminate 1 in the thickness direction. The total light transmittance of the glass plate 2 is, for example, 80% or more, preferably 85% or more, and 99% or less. As the glass plate 2, commercially available products can be used, and for example, G-leaf series (registered trademark, manufactured by Nippon electric Co., ltd.) can be used.

The thickness of the glass plate 2 is not limited. The thickness of the glass plate 2 is, for example, 1 μm or more, preferably 10 μm or more, and more preferably 20 μm. The thickness of the glass plate 2 is 100 μm or less, preferably 80 μm or less, more preferably 60 μm or less, and still more preferably 50 μm or less.

< adhesive layer 3 >)

The adhesive layer 3 extends in the plane direction. The adhesive layer 3 is disposed on one surface of the glass plate 2 in the thickness direction. Specifically, the adhesive layer 3 is in contact with one surface of the glass plate 2 in the thickness direction. The adhesive layer 3 is not an adhesive layer (pressure-sensitive adhesive layer) formed of an adhesive (pressure-sensitive adhesive), but is a cured product of a curable adhesive. Specifically, the adhesive layer 3 is a cured product of a curable adhesive that undergoes a curing reaction upon irradiation or heating with active energy rays.

The curable adhesive is a curing raw material for the adhesive layer 3, and may be an active energy curing type or a thermosetting type, and may be preferably an active energy curing type. Specifically, examples of the curable adhesive include: acrylic adhesive compositions, epoxy adhesive compositions, and silicone adhesive compositions are exemplified as the epoxy adhesive compositions from the viewpoint of obtaining excellent impact resistance.

The epoxy adhesive composition contains an epoxy resin as a main agent. Examples of the epoxy resin include: difunctional epoxy resins having 2 epoxy groups, multifunctional epoxy resins having 3 or more epoxy groups, and the like. These epoxy resins may be used singly or in combination of two or more.

The combination of a difunctional epoxy resin and a polyfunctional epoxy resin may be preferably used.

Examples of the difunctional epoxy resin include: bisphenol type epoxy resin, novolac type epoxy resin, naphthalene type epoxy resin, fluorene type epoxy resin, triphenylmethane type epoxy resin, nitrogen-containing ring-containing epoxy resin such as triglycidyl isocyanurate and hydantoin type epoxy resin, aliphatic type epoxy resin, glycidyl ether type epoxy resin, and glycidyl amine type epoxy resin. As the difunctional epoxy resin, aliphatic epoxy resins are preferable. The aliphatic epoxy resin includes an aliphatic alicyclic epoxy resin. The epoxy equivalent of the difunctional epoxy resin is, for example, 100g/eq. Or more, preferably 120g/eq. Or more, and 250g/eq. Or less, preferably 150g/eq. Or less. The proportion of the difunctional epoxy resin in the epoxy resin is, for example, 80% by mass or more, preferably 90% by mass or more, and 99% by mass or less, preferably 97% by mass or less.

Examples of the polyfunctional epoxy resin include: phenol novolac type epoxy resins, cresol novolac type epoxy resins, trihydroxyphenyl methane type epoxy resins, tetraphenyl ethane (tetraphenyl ethane) type epoxy resins, dicyclopentadiene type epoxy resins, trifunctional aliphatic epoxy resins, and the like. As the polyfunctional epoxy resin, a trifunctional aliphatic epoxy resin is preferable. The epoxy equivalent of the multifunctional epoxy resin is, for example, 130g/eq. Or more, preferably 150g/eq. Or more, and 220g/eq. Or less, preferably 200g/eq. Or less. 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 mass% or more, preferably 75 mass% or more, and is, for example, 90 mass% or less, preferably 80 mass% or less.

The epoxy resin may be a commercially available product, and as the aliphatic alicyclic epoxy resin, CELLOXIDE 2021P (manufactured by cellophane chemical company, ltd.) may be used, and as the trifunctional aliphatic epoxy resin, EHPE3150 (manufactured by cellophane chemical company, ltd.) and the like may be used.

In addition, the epoxy adhesive composition contains a photoacid generator if it is an active energy curing type. Examples of the photoacid generator include: triarylsulfonium salts, and the like. As the photoacid generator, commercially available ones can be used, and CPI101A (manufactured by San-Apro Co.) and the like can be used as the 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.

Further, the epoxy adhesive composition may contain additives such as oxetane-based resin, silane coupling agent, and the like in an appropriate ratio.

Examples of the oxetane resin include: monofunctional oxetanes such as 3-ethyl-3-oxetanemethanol and 2-ethylhexyl oxetane, difunctional oxetanes such as xylylene dioxetane and 3-ethyl-3 { [ (3-ethyloxetan-3-yl) methoxy ] methyl } oxetane. As the OXETANE resin, commercially available ones can be used, and ARON OXETANE (manufactured by Toyama Co., ltd.) and the like can be used.

Examples of the silane coupling agent include: epoxy group-containing silane coupling agents such as 3-glycidoxypropyl trimethoxysilane. As the silane coupling agent, commercially available ones can be used, and KBM series (manufactured by Shin-Etsu Silicone Co., ltd.) and the like can be cited.

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

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

The tensile storage modulus E' of the adhesive layer 3 at 25 ℃ is, for example, 1GPa or more, preferably 2GPa or more, more preferably 3GPa or more, still more preferably 4GPa or more, and is, for example, 100GPa or less. The tensile storage modulus E' of the adhesive layer 3 at 25℃can be obtained by measuring the dynamic viscoelasticity in a temperature dispersion mode under conditions of a frequency of 1Hz and a temperature rising rate of 5 ℃/min. The adhesive layer 3 has an elastic modulus at 25 ℃ of, for example, 1GPa or more, preferably 2GPa or more, more preferably 3GPa or more, still more preferably 4GPa or more, and further, for example, 100GPa or less, as measured by the nanoindentation method. The measurement conditions of the nanoindentation method are as follows.

The device comprises: triboindeter (Hysicron Inc. manufactured by Hysicron Inc.)

Sample size: 10X 10mm

Pressure head: concial (spherical indenter: radius of curvature 10 μm)

The measuring method comprises the following steps: single press-in assay

Measuring temperature: 25 DEG C

Depth of press-in of press head: 100nm of

Temperature: 25 DEG C

Analysis: oliver Pharr resolution based on load-displacement curve

The adhesion force between the glass plate 2 and the adhesive layer 3 is, for example, 3.0kN/m or more, preferably 3.5kN/m or more, more preferably 4.0kN/m or more, and is, for example, 10kN/m or less, preferably 8kN/m or less. If the adhesion force between the glass plate 2 and the adhesive layer 3 is equal to or greater than the lower limit, separation at the interface between the glass plate 2 and the adhesive layer 3 can be suppressed when an object collides with the optical laminate 1. Therefore, the optical laminate 1 is excellent in reliability.

As shown in fig. 2C, the edge 43 of the blade 42 provided in the device 41 is inserted into the interface between the glass plate 2 and the adhesive layer 3, and the blade 42 is moved in the surface direction, so that the adhesive force between the glass plate 2 and the adhesive layer 3 is obtained as the peel strength at the time of peeling the glass plate 2 from the adhesive layer 3. Details of the method for measuring the adhesion force are described in examples below.

< Membrane 4 >)

The film 4 forms one surface (visible side surface) in the thickness direction of the optical laminate 1. The film 4 is located on the opposite side of the adhesive layer 3 from the glass plate 2. The film 4 extends in the plane direction.

The film 4 is disposed on one surface in the thickness direction of the adhesive layer 3. The film 4 is in contact with one surface of the adhesive layer 3 in the thickness direction. Thus, the adhesive layer 3 contacts one surface of the glass plate 2 in the thickness direction and the other surface of the film 4 in the thickness direction, and the glass plate 2 and the film 4 are bonded (joined) together.

The average value of tan delta at-100 ℃ to-50 ℃ of the film 4 obtained by the dynamic viscoelasticity test at a frequency of 10Hz, a heating rate of 2 ℃/min, a data acquisition interval of 0.5min, and a stretching mode is, for example, 0.02 or more, preferably 0.04 or more, and is, for example, 0.20 or less, preferably less than 0.06, more preferably 0.05 or less. If the average value of tan delta of the film 4 at-100 to-50 ℃ is higher than the lower limit, the impact resistance of the optical laminate 1 can be improved. The average value of tan delta of the film 4 at-100 ℃ to-50 ℃ is an index that characterizes the responsiveness of an object when it collides with the optical laminate 1 at high speed. the higher the average value of tan δ, the more the film 4 can sufficiently alleviate the impact received by the glass plate 2 even if the object collides with the glass plate 2 at a high speed, and the impact resistance of the optical laminate 1 can be improved. Dynamic viscoelasticity tests are described in the examples below.

The average value of the tensile storage modulus E' of the film 4 at-100℃to-50℃as determined by the dynamic viscoelasticity test at a frequency of 10Hz, a heating rate of 2℃per minute, and a stretching mode is, for example, 3GPa or more, preferably 4GPa or more, and is, for example, 10GPa or less, preferably 6GPa or less, more preferably 5GPa or less, and still more preferably 4.7GPa or less. If the average value of the tensile storage modulus E' of the film 4 at-100 ℃ to-50 ℃ is not less than the lower limit, the impact resistance of the optical laminate 1 can be improved.

The adhesion force between the film 4 and the adhesive layer 3 is, for example, 0.5kN/m or more, preferably 1.5kN/m or more, more preferably 3.0kN/m or more, still more preferably 3.5kN/m or more, particularly preferably 4.0kN/m or more, most preferably 5.0kN/m or more, and further, for example, 10kN/m or less. If the adhesion force between the film 4 and the adhesive layer 3 is equal to or greater than the lower limit, peeling at the interface between the film 4 and the adhesive layer 3 can be suppressed when an object collides with the film 4 of the optical laminate 1. As shown in fig. 2B, the edge 43 of the blade 42 provided in the measuring device 41 is inserted into the interface between the film 4 and the adhesive layer 3, and the blade 42 is moved in the plane direction, so that the adhesive force between the film 4 and the adhesive layer 3 is obtained as the peel strength when the film 4 is peeled from the adhesive layer 3. Details of the method for measuring the adhesion force are described in examples below.

Examples of the film 4 include a polyester film and a cellulose film. Examples of the polyester film include: polyethylene terephthalate (PET), polybutylene terephthalate (PBT), and polyethylene naphthalate (PEN) films. Examples of the cellulose film include a cellulose acetate film, and specifically a cellulose Triacetate (TAC) film. The film 4 is preferably a cellulose film, and more preferably a TAC film, from the viewpoints of improving the adhesion of the film 4 to the adhesive layer 3 and suppressing peeling of the film 4 when an object collides with the optical laminate 1.

The thickness of the film 4 is not limited. The thickness of the film 4 is, for example, 10 μm or more, preferably 30 μm or more. If the thickness of the film 4 is not less than the lower limit, the impact resistance of the optical laminate 1 can be improved. The thickness of the film 4 is, for example, 200 μm or less, preferably 100 μm or less, and more preferably 60 μm or less. If the thickness of the film 4 is equal to or less than the upper limit, peeling of the film 4 at the time of collision of the object with the optical laminate 1 can be suppressed.

The total light transmittance of the film 4 is, for example, 80% or more, preferably 85% or more, and 99% or less.

< adhesive layer 12 >)

The optical laminate 1 may further include an adhesive layer 12 shown by a phantom line. The adhesive layer 12 is disposed on the other surface in the thickness direction of the glass plate 2. Specifically, the adhesive layer 12 is in contact with the other side in the thickness direction of the film 4. That is, the optical laminate 1 includes, in order from one side in the thickness direction, an adhesive layer 12, a glass plate 2, an adhesive layer 3, and a film 4. The adhesive layer 12 is an adhesive body that performs pressure-sensitive adhesion without accompanying a curing reaction.

The material of the adhesive layer 12 is not limited. Examples of the material of the pressure-sensitive adhesive layer 12 include: acrylic adhesives, rubber adhesives, vinyl alkyl ether adhesives, silicone adhesives, polyester adhesives, polyamide adhesives, urethane adhesives, fluorine adhesives, epoxy adhesives, and polyether adhesives. As the material, an acrylic adhesive may be preferable. The formulation and physical properties of the pressure-sensitive adhesive layer 12 are described in detail in, for example, japanese patent application laid-open No. 2018-28573.

The shear storage modulus G' of the adhesive layer 12 at 25℃is, for example, 0.01MPa or more and, for example, 0.20MPa or less. The shear storage modulus G' can be obtained by a dynamic viscoelasticity test in shear (torsion) mode at a frequency of 1Hz and a heating rate of 5 ℃/min.

The thickness of the pressure-sensitive adhesive layer 12 is, for example, 5 μm or more, preferably 10 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 layered body 1 is, for example, 25 μm or more and, further, 200 μm or less.

< test of break in pen >)

In the pen breakage test, the pen drop height H1 of the optical laminate 1 until the glass plate 2 starts to break is, for example, 15cm or more.

First, the optical laminate 1 is placed on the surface of a horizontal table (not shown) with a resin film 34 shown in phantom lines interposed therebetween. The adhesive layer 12 having a thickness of 15 μm was disposed on one surface in the thickness direction of the optical laminate 1. The adhesive layer 12 also serves as a fixing member for fixing the optical laminate 1 to a horizontal stage in the drop break test. The shear storage modulus G' at 25 ℃ is 0.03MPa, which is obtained by a dynamic viscoelasticity test with the frequency of 1Hz, the heating rate of 5 ℃/min and the temperature of-40 ℃ to 150 ℃ and the torsion mode.

As shown in FIG. 1, the pen 29 (Pentel ballpoint BK407 black, ball diameter 0.7 mm) was dropped toward the film 4. The mass of pen 29 is 7g. The height from the glass plate 2 to the tip 32 of the pen 29 was 5cm. The tip portion 32 is pointed downward. If the glass plate 2 is not broken by the above-described drop of the pen 29, the height is gradually increased by 1cm each time. The height at which breakage of the glass plate 2 was confirmed was obtained as a height H1 in the drop breakage test.

If the drop height H1 in the drop break test is 15cm or more, the optical laminate 1 is excellent in impact resistance.

The drop height H1 in the drop break test is preferably 20cm or more.

< Pen-drop peel test >)

In the drop peeling test of the optical laminate 1, the drop height H2 of the pen 29 until the film 4 starts peeling is, for example, 15cm or more.

First, the optical laminate 1 is placed on the surface of a horizontal table (not shown) with a resin film 34 shown in phantom lines interposed therebetween. The adhesive layer 12 similar to the adhesive layer 12 used in the drop break test was disposed on one surface in the thickness direction of the optical laminate 1.

As shown in FIG. 1, the pen 29 (Pentel ballpoint BK407 black, ball diameter 0.7 mm) was dropped toward the film 4. The mass of pen 29 is 7g. The height from the glass plate 2 to the front end 32 of the pen 29 is 5cm. The tip portion 32 is pointed downward. If peeling of the film 4 from the adhesive layer 3 does not occur due to the above-described drop of the pen 29, the height is gradually increased by 1cm each time. The height at which peeling of the film 4 from the adhesive layer 3 was confirmed was obtained as the height H2 in the drop peeling test. Alternatively, when the glass plate 2 is broken, it is determined that the glass plate has peeling durability equal to or higher than the breaking height H1.

The drop height H2 in the drop peel test is preferably 20cm or more.

In the optical laminate 1 satisfying the above requirements, the adhesion force of the film 4 to the adhesive layer 3 is high. Therefore, the optical laminate 1 is excellent in reliability.

Method for producing optical layered body 1

A method of manufacturing the optical layered body 1 will be described. In the method for producing the optical laminate 1, for example, a curable adhesive is first disposed (coated) on one surface in the thickness direction of the glass plate 2 and/or the other surface in the thickness direction of the film 4, and then the curable adhesive is sandwiched between the glass plate 2 and the film 4.

Then, the curable adhesive is cured. If the curable adhesive is an active energy curable adhesive, the curable adhesive is irradiated with active energy including ultraviolet rays. Specifically, ultraviolet rays are irradiated from the glass plate 2 side to the curable adhesive. If the curable adhesive is a thermosetting adhesive, the curable adhesive is heated. Thereby, the adhesive layer 3 is formed to strongly adhere the glass plate 2 and the film 4.

Thus, an optical laminate 1 including the glass plate 2, the adhesive layer 3, and the film 4 was obtained.

Then, in order to further provide the optical laminate 1 with the adhesive layer 12, the adhesive layer 12 is disposed on the other surface in the thickness direction of the glass plate 2. For example, a varnish containing an adhesive is applied to the other surface of the glass plate 2 in the thickness direction and dried. Alternatively, the pressure-sensitive adhesive layer 12 formed on a release sheet, not shown, may be transferred to the other surface of the glass plate 2 in the thickness direction. Thus, an optical laminate 1 including the adhesive layer 12, the glass plate 2, the adhesive layer 3, and the film 4 was obtained. The optical laminate 1 may be provided with a release sheet, not shown. In this case, the optical laminate 1 includes a release sheet, an adhesive layer 12, a glass plate 2, an adhesive layer 3, and a film 4, which are not shown.

Use of optical laminate 1

The optical layered body 1 can be used for various optical applications, and can be disposed in an image display device, for example. Examples of the image display device include an organic electroluminescence display device (hereinafter simply referred to as an "organic EL display device").

Next, an organic EL display device 10 including the optical layered body 1 will be described with reference to fig. 3.

< organic EL display device 10 >)

The organic EL display device 10 has a flat plate shape extending in the plane direction. The organic EL display device 10 includes a conductive film 13 to be described later, and thus functions as a touch panel type input display device. The organic EL display device 10 includes, in order toward the back surface side: an optical laminate 1, a conductive film 13, a 2 nd adhesive layer 14, and an image display member 15. In the organic EL display device 10, the upper side of the paper surface is the user-visible side (corresponding to the other side in the thickness direction of fig. 1), and the lower side of the paper surface is the back side (corresponding to the one side in the thickness direction of fig. 1).

< optical laminate 1 >)

The optical laminate 1 includes, in order toward the front surface, an adhesive layer 12, a glass plate 2, an adhesive layer 3, and a film 4.

< conductive film 13 >)

The conductive film 13 includes a conductive layer 16 and a base layer 17 in this order toward the back surface side.

< conductive layer 16 >)

The conductive layer 16 has a given pattern. The surface and side of the conductive layer 16 are in contact with the adhesive layer 12. Examples of the material of the conductive layer 16 include: metal oxide, conductive fibers (fibers), and metal. As the metal oxide, a composite oxide is exemplified. Examples of the complex oxide 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 (ATO). Examples of the conductive fiber include: metal nanowires, and carbon nanotubes. Examples of the metal include: gold, platinum, silver, and copper. The conductive layer 16 integrally has a sensor electrode portion 18 located at the center in the plane direction, and a lead-out wiring portion 19 located at the periphery of the sensor electrode portion 18. Details of the conductive layer 16 are described in, for example, japanese patent application laid-open No. 2017-102443, japanese patent application laid-open No. 2014-113705, and Japanese patent application laid-open No. 2014-219667.

< substrate layer 17 >)

The base material layer 17 is disposed 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 planar direction. The base material layer 17 is, for example, a resin layer. Examples of the material of 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. Examples of the olefin resin include: polyethylene, polypropylene, and Cyclic Olefin Polymer (COP). Examples of the polyester resin include: PET, PBT, and PEN. Examples of the (meth) acrylic resin include: poly (meth) acrylate resins. Details of the base material layer 17 are described in, for example, japanese patent application laid-open No. 2018-181722.

< 2 nd adhesive layer 14 >

The 2 nd adhesive layer 14 is disposed on the back surface of the conductive film 13. Specifically, the 2 nd adhesive layer 14 is in contact with the back surface of the conductive film 13. The material of the 2 nd adhesive layer 14 is the same as the material of 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 disposed on the back surface side of the conductive film 13 via the 2 nd adhesive layer 14. The image display member 15 extends in the plane direction. The image display member 15 is specifically an organic EL element. Although not shown, the image display member 15 includes, for example, a display substrate, two electrodes, an organic EL layer sandwiched between the two electrodes, and a sealing layer. The structure and physical properties of the image display member 15 are described in detail in, for example, japanese patent application laid-open No. 2018-28573.

Effect of one embodiment >

The optical laminate 1 according to one embodiment has a novel structure in which the film 4 is disposed on the visible side and the glass plate 2 is disposed on the opposite side. In the optical laminate 1, the drop height H1 of the pen is 15cm or more until the glass plate starts to fracture in the pen breakage test. Therefore, the optical laminate 1 is excellent in impact resistance.

In addition, in the drop test, the drop height H2 of the pen until the film 4 starts to peel is 15cm or more. Therefore, the film 4 is excellent in adhesion. Therefore, the optical laminate 1 is excellent in reliability.

Further, since the average value of tan δ at-100 ℃ to-50 ℃ of the film 4 is 0.04 or more and the average value of the tensile storage modulus E' of the film 4 at-100 ℃ to-50 ℃ is 3GPa to 6GPa, breakage of the glass plate 2 in the drop break test can be suppressed. Therefore, the optical laminate 1 is excellent in impact resistance.

In the optical laminate 1, the adhesion force between the glass plate 2 and the adhesive layer 3 is 3.0kN/m or more, and the adhesion force between the film 4 and the adhesive layer 3 is 3.0kN/m or more, so that the adhesion force between each of the film 4 and the glass plate 2 with respect to the adhesive layer 3 is excellent. Therefore, the optical laminate 1 is excellent in reliability.

In addition, if the film 4 is a TAC film, the adhesion to the adhesive layer 3 is excellent.

Therefore, the optical laminate 1 is excellent in reliability.

In addition, if the thickness of the film 4 is 60 μm or less, peeling of the film 4 from the adhesive layer 3 can be suppressed from occurring when an object collides with the optical laminate 1.

The optical laminate of the present invention has excellent impact resistance, and therefore, even a glass plate having a thickness of less than 40 μm has sufficient impact resistance.

< modification >

In the following modification, the same members and steps as those in the above embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. Further, the modified example can exhibit the same operational effects as those of the one embodiment unless otherwise described.

In one embodiment, the film 4 is a single layer, but the number of layers of the film 4 is not limited.

The film 4 may also be a multilayer.

As shown by the one-dot chain line in fig. 1, the optical laminate 1 may further include a hard coat layer 38. The hard coat layer 38 is disposed on one surface in the thickness direction of the film 4. The hard coat layer 38 is in contact with one surface in the thickness direction of the film 4. The optical laminate 1 includes, in order from the viewing side, a glass plate 2, an adhesive layer 3, a film 4, and a hard coat layer 38. The formulation, physical properties, and dimensions of the hard coat layer 38 are not particularly limited. In this modification, since the optical laminate 1 includes the hard coat layer 38, the impact resistance and scratch resistance of the optical laminate 1 can be improved.

Other functional layers may be provided instead of the hard coat layer 38 or may be further provided. Examples of the other functional layer include an anti-scattering layer, an anti-staining layer, and an anti-reflection layer. These layers may be single layers or may be laminated in a plurality of layers.

The optical laminate of the present invention has excellent impact resistance, and therefore, even a glass plate having a thickness of less than 40 μm has sufficient impact resistance. The optical laminate of the present invention can be suitably used for flexible displays such as a folding display and a roll display because of excellent bending properties of a glass sheet having a thickness of less than 40. Mu.m.

Examples

Specific numerical values such as the blending ratio (containing ratio), physical property value, and parameter used in the following description may be replaced with the upper limit value (numerical value defined in the form of "below", "less than") or the lower limit value (numerical value defined in the form of "above", "exceeding") described in the above-described "specific embodiment" corresponding to these numerical values, physical property value, parameter, and the like. In the following description, unless otherwise specified, "parts" and "%" are mass references.

In the following examples and comparative examples, an optical laminate 1 was produced, and then an adhesive layer 12 was disposed on the optical laminate 1, and the impact resistance of the optical laminate 1 was evaluated.

Example 1

A glass plate 2 (G-leaf) having a thickness of 30 μm and a film 4 (DIAFOIL S100, mitsubishi chemical Co., ltd.) having a thickness of 50 μm and formed of a polyethylene terephthalate film were prepared. Further, an epoxy adhesive composition was prepared by blending 70 parts by mass of an aliphatic alicyclic epoxy resin (CELLOXIDE 2021P, epoxy equivalent 128 to 133g/eq., manufactured by Cellophane chemical Co., ltd.), 5 parts by mass of a trifunctional aliphatic epoxy resin (EHPE 3150, epoxy equivalent 170 to 190g/eq., manufactured by Cellophane chemical Co., ltd.), 19 parts by mass of an OXETANE resin (ARON OXETANE, manufactured by Toyama Co., ltd.), 4 parts by mass of a silane coupling agent (KBM-403, 3-epoxypropoxypropyl trimethoxysilane, manufactured by Xinyue chemical Co., ltd.), and 2 parts by mass of a photoacid generator (CPI 101A, triarylsulfonium salt, manufactured by SanApro chemical Co., ltd.). The epoxy adhesive composition is applied to the glass plate 2, and then the epoxy adhesive composition is sandwiched by the glass plate 2 and the film 4.

Then, the curable adhesive is irradiated with ultraviolet rays from the glass plate 2 side. Thus, the adhesive layer 3 having a thickness of 1 μm formed of the cured product was formed by strongly bonding the glass plate 2 and the film 4. The elastic modulus of the adhesive layer 3 measured by nanoindentation was 4.9GPa at 25 ℃. Thus, the optical laminate 1 including the glass plate 2, the adhesive layer 3, and the film 4 was produced.

Next, the adhesive layer 12 having a thickness of 15 μm was disposed on the other surface of the glass plate 2 in the thickness direction by transfer. The adhesive layer 12 was prepared as follows.

A base polymer composition (polymerization ratio: about 10%) was obtained by polymerizing 43 parts by mass of Lauryl Acrylate (LA), 44 parts by mass of 2-ethylhexyl acrylate (2 EHA), 6 parts by mass of 4-hydroxybutyl acrylate (4 HBA), 7 parts by mass of N-vinyl-2-pyrrolidone (NVP), and 0.015 part by mass of "IRGACURE 184" made by BASF by irradiation with ultraviolet light.

Further, 60 parts by mass of dicyclohexyl 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 stirred at 70℃for 1 hour in a nitrogen atmosphere. Next, 0.2 parts by mass of 2,2' -Azobisisobutyronitrile (AIBN) was charged, reacted at 70℃for 2 hours, and then heated to 80℃to react for 2 hours. Then, the reaction solution was heated to 130℃and toluene, a chain transfer agent and unreacted monomers were dried and removed to obtain a solid acrylic oligomer. The weight average molecular weight of the acrylic oligomer was 5100. The glass transition temperature (Tg) was 130 ℃.

An adhesive composition was prepared by adding 0.07 part by mass of 1, 6-hexanediol diacrylate (HDDA), 1 part by mass of an acrylic oligomer, and 0.3 part by mass of a silane coupling agent (KBM 403 "by shi chemical system of information and transmission) to 100 parts by mass of the solid content of the base polymer composition, and then uniformly mixing them.

The adhesive composition was applied to the surface of a release sheet composed of a PET film (mitsubishi chemical product "diaface MRF 75"), and then another release sheet composed of a PET film (mitsubishi chemical product "diaface MRF 75") was attached to the coating film. Then, the film was irradiated with ultraviolet rays to prepare an adhesive layer 12 having a thickness of 15. Mu.m. The shear storage modulus G' of the adhesive layer 12 at 25℃was 0.03MPa. The measurement method is as follows.

The adhesive layer 12 was formed into a disc shape, and the shear storage modulus G' of the adhesive layer 12 at 25 ℃ was obtained by dynamic viscoelasticity measurement under the following conditions using "Advanced Rheometric Expansion System (ARES)" manufactured by Rheometric Scientific company, sandwiched between parallel plates.

[ Condition ]

Mode: torsion

Temperature: -40-150 DEG C

Heating rate: 5 ℃/min

Frequency: 1Hz

Example 2

An optical laminate 1 was produced in the same manner as in example 1. The film 4 was changed to a cellulose triacetate film (KC 4, UYW, manufactured by Konikoku Meida) having a thickness of 40. Mu.m.

Example 3

An optical laminate 1 was produced in the same manner as in example 1. The film 4 was changed to a cellulose triacetate film (KC 2CT, manufactured by Konikoku Meida) having a thickness of 20. Mu.m.

Example 4

An optical laminate 1 was produced in the same manner as in example 2. The film 4 was changed to a cellulose triacetate film (KC 8, UAW, manufactured by Konikoku Meida) having a thickness of 80. Mu.m.

Comparative example 1

An optical laminate 1 was produced in the same manner as in example 1. Among them, as the film 4, an acrylic film obtained by molding a methacrylic resin pellet having a glutarimide ring unit into a film shape by extrusion molding and then stretching the film was used. The thickness of the acrylic film was 40. Mu.m.

The types and thicknesses of the films 4 in each example and comparative example are shown in table 1.

< evaluation >

For each example and comparative example, the following matters were measured and evaluated. The results are shown in Table 1.

< tan delta and tensile storage modulus E' >, of film 4

The films 4 prepared in each of the examples and comparative examples were subjected to dynamic viscoelasticity test. The apparatus and conditions are described below.

The device comprises: multifunctional dynamic viscoelasticity measuring device DMS6100 manufactured by Hitachi High-Tech Science Co., ltd

Temperature range: 100-200 DEG C

Heating rate: 2 ℃/min

Mode: stretching

Sample width: 10mm of

Distance between chucks: 20mm of

Frequency: 10Hz

Strain amplitude: 10 μm

Atmosphere: atmosphere (250 ml/min)

Data acquisition interval: 0.5min (every 1 ℃ C.)

The average value of the tensile storage modulus E' of the film 4 at-100℃to-50℃is calculated by dividing the sum of all the data obtained above at-100℃to-50℃by the number of data, respectively. The average value of tan delta of the film 4 at-100 ℃ to-50 ℃ is calculated by dividing the total of all the data obtained above at-100 ℃ to-50 ℃ by the number of data, respectively.

< adhesion force of film 4 and adhesive layer 3 >

The adhesion force between the film 4 and the adhesive layer 3 was measured by the following apparatus, conditions and method using a surface/interface physical property analyzer.

The device comprises: DAIPLA WINTES surface/interface physical Property analysis device (SAICAS DN-20)

The material of the blade 42: single crystal diamond

Width of the cutting edge 43: 1mm of

Nose angle of nose 43: 10 degree

As shown in fig. 2A, the surface/interface physical property analysis device 41 includes a blade 42, a moving device and a pressure measuring unit, which are not shown. The blade 42 is movable. The blade 42 includes a cutting edge 43 formed at a lower end.

As shown in fig. 2A, the optical layered body 1 is set in the measuring device 41. In this case, the film 4 is disposed on the upper side, and the glass plate 2 is disposed on the lower side.

The cutting edge 43 is moved obliquely downward in the horizontal direction (corresponding to the plane direction of the optical laminate 1). The horizontal velocity was 10 μm/sec, and the vertical velocity was 0.5 μm/sec. Thereby, the cutting edge 43 cuts into the film 4.

As shown in fig. 2B, when the edge 43 reaches the interface between the film 4 and the adhesive layer 3, the edge 43 is moved only in the horizontal direction. The horizontal direction velocity was maintained at 10 μm/sec. The film 4 is peeled from the adhesive layer 3 by the movement of the blade edge 43 in the horizontal direction. The peel strength at this time was measured as the adhesion force between the film 4 and the adhesive layer 3.

< adhesion force between glass plate 2 and adhesive layer 3 >

The adhesion force between the glass plate 2 and the adhesive layer 3 was measured by the same apparatus, conditions and method as described above. As shown in fig. 2C, the edge 43 is cut into the adhesive layer 3 after cutting into the film 4, and the edge 43 is moved horizontally when the edge 43 reaches the interface between the adhesive layer 3 and the glass plate 2. Thereby, the adhesive layer 3 is peeled from the glass plate 2. The peel strength at this time was measured as the adhesion force between the glass plate 2 and the adhesive layer 3.

< test of break in pen >)

The following pen-down fracture test was performed on the optical layered body 1 of each of the examples and comparative examples. First, as shown in fig. 1, the optical laminate 1 is placed on the surface of the resin film 34 (virtual line) so that the film 4 is directed upward. Specifically, the adhesive layer 12 is bonded to the surface of the resin film 34. The resin film 34 is Prescale (Prescale MS medium pressure monolithic, manufactured by Fuji film Co., ltd., thickness of 95 μm). The resin film 34 is disposed on the surface of a horizontal stage, not shown. Next, a pen-down breakage test was performed in which 7g of the pen 29 (Pentel ballpoint BK407 black, ball diameter 0.7 mm) was dropped from a height of 5cm from the film 4. The height 5cm is a distance between one surface of the film 4 in the thickness direction and the tip portion 32 of the pen 29. The tip portion 32 is pointed downward. In the optical laminate 1, if the glass plate 2 is broken due to the above drop of the pen 29, the height H1 of the pen-drop breaking test is 5cm. If the glass plate 2 is not broken, the height is gradually increased by 1cm each time. Thus, the height H1 at which the glass plate 2 breaks is obtained.

< Pen-drop peel test >)

The pen 29 was dropped onto the film 4 in the same manner as in the above-described pen-down breakage test. The initial drop height was set to 5cm. Then, if peeling of the film 4 from the adhesive layer 3 did not occur, the height was gradually increased by 1cm each time. The height at which the film 4 was peeled off from the adhesive layer 3 was confirmed as the height H2 in the drop peeling test. Alternatively, when the glass plate 2 is broken, it is determined that the glass plate has peeling durability equal to or higher than the breaking height H1.

Table 1

The above-described invention is provided as an exemplary embodiment of the present invention, but is merely exemplary and not to be construed as limiting. It will be apparent to those skilled in the art that modifications of the present invention are encompassed by the appended claims.

Industrial applicability

The optical layered body may be provided in an image display device.

Claims

1. An optical laminate comprising a glass plate, an adhesive layer and a film in this order toward one side in the thickness direction,

one side in the thickness direction is a visible side,

in the pen-down breaking test described below, the pen-down height H1 until the glass plate starts breaking was 15cm or more,

< test of break in pen >)

An adhesive layer was disposed on the other surface of the optical laminate in the thickness direction, a ball-point pen having a ball diameter of 0.7mm and 7G was dropped onto the film, the dropping height of the pen was increased by 1cm each time, and a height at which breakage was confirmed in the glass plate was obtained as a height H1 in a drop breakage test, the thickness of the adhesive layer was 15 μm, and a shear storage modulus G' at 25℃was 0.03MPa as determined by a dynamic viscoelasticity test at a frequency of 1Hz, a heating rate of 5 ℃/min, a temperature of-40℃to 150℃and a torsion mode.

2. The optical stack according to claim 1, wherein,

< Pen-drop peel test >)

The pressure-sensitive adhesive layer was disposed on the other surface of the optical laminate in the thickness direction, a ballpoint pen having a ball diameter of 0.7mm and 7g was dropped onto the film, and the drop height of the pen was gradually increased to 30cm, whereby a height at which peeling of the film was confirmed was obtained as a height H2 in a drop peeling test, or when the glass plate was broken, it was determined that the film had peeling durability of not less than the breaking height H1.

3. The optical laminate according to claim 1 or 2, wherein,

4. The optical laminate according to claim 1 or 2, wherein,

the film and the adhesive layer have an adhesion force of 3.0kN/m or more.

5. The optical laminate according to claim 1 or 2, wherein,

the membrane is a cellulose triacetate membrane.

6. The optical stack according to claim 5, wherein,

the film has a thickness of 10 μm or more and 60 μm or less.

7. The optical laminate according to any one of claims 1 to 6, further comprising a hard coat layer disposed on one surface of the film in the thickness direction.