KR102390821B1 - Optical laminate with cover glass and image display device with cover glass - Google Patents

Abstract

An optical laminate with a cover glass in which cracks were suppressed, and an image display device with a cover glass comprising such an optical laminate with a cover glass are provided. The optical laminate with a cover glass of the present invention includes a cover glass, a first pressure-sensitive adhesive layer, an optical film, and a second pressure-sensitive adhesive layer in this order, and the storage elastic modulus (G1') at -40°C of the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer 2 Ratio G ₁ '/G ₂ ' of the storage elastic modulus (G2') in -40 degreeC of 2 adhesive layers is 1 or more. The image display apparatus with a cover glass of this invention contains a display cell and the optical laminated body with a cover glass of this invention arrange|positioned at the visual recognition side of a display cell.

Description

Optical laminate with cover glass and image display device with cover glass

The present invention relates to an optical laminate with a cover glass and an image display device with a cover glass.

DESCRIPTION OF RELATED ART Various optical laminated bodies (for example, a polarizing plate) are used for image display apparatuses, such as a mobile phone and a notebook personal computer, in order to implement|achieve image display and/or to improve the performance of the said image display. After an optical laminated body is cut|disconnected to a predetermined shape, a cut surface may be used for finishing processing by cutting. Moreover, in recent years, it may be preferable to process (release processing) an optical laminated body other than a rectangle. In such a cutting process, cutting by an end mill may be performed. However, the optical laminated body cut by the end mill may generate|occur|produce a crack. In addition, since an optical laminated body may be provided in the state which laminated|stacked the cover glass (optical laminated body with a cover glass), a crack may generate|occur|produce also in the optical laminated body with a cover glass.

Japanese Laid-Open Patent Publication No. 2007-187781 Japanese Laid-Open Patent Publication No. 2018-022140

The present invention has been made in order to solve the above conventional problems, and its main object is to provide an optical laminate with a cover glass in which cracks are suppressed, and an image display device with a cover glass comprising such an optical laminate with a cover glass. there is.

The optical laminate with a cover glass of the present invention includes a cover glass, a first pressure-sensitive adhesive layer, an optical film, and a second pressure-sensitive adhesive layer in this order, and the storage elastic modulus (G1') at -40°C of the first pressure-sensitive adhesive layer and Ratio G1'/G2' with the storage elastic modulus (G2') in -40 degreeC of this 2nd adhesive layer is 1 or more.

In one embodiment, the storage elastic modulus (G1') in -40 degreeC of the said 1st adhesive layer is 5.0x10 ⁶ (Pa) or more.

In one embodiment, the said optical laminated body with a cover glass contains the cutting cross section in which the said optical film and the said 2nd adhesive layer have a cut mark at least.

In one embodiment, the machined portion comprises a recess when viewed in plan.

In one embodiment, the optical film comprises a polarizer. In one embodiment, the optical film further includes a protective film on the side of the first pressure-sensitive adhesive layer of the polarizer.

In one embodiment, the hard-coat layer is formed in the said protective film.

In one embodiment, break elongation in 25 degreeC of the said protective film is 2 mm or more.

According to another aspect of this invention, the image display apparatus with a cover glass is provided. This image display apparatus with a cover glass contains a display cell and the said optical laminated body with a cover glass arrange|positioned at the visual recognition side of this display cell.

According to embodiment of this invention, in an optical laminated body with a cover glass, by making the storage elastic modulus of the adhesive layer which bonds a cover glass and an optical film more than the storage elastic modulus of the adhesive layer which bonds an optical laminated body to a display cell, crack, (Actually, cracks of an optical film: cracks after a heat cycle test in particular) can be suppressed.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic sectional drawing explaining the optical laminated body with a cover glass by one Embodiment of this invention.
It is a schematic plan view which shows an example of the shape of the optical laminated body with cover glass by which the cutting process of this invention was carried out.
It is a schematic perspective view for demonstrating an example of the cutting process of the optical laminated body with a cover glass of this invention.
It is a schematic perspective view for demonstrating an example of the cutting means used for the cutting in the manufacturing method of the optical laminated body with a cover glass of this invention.
Fig. 5 (a) is a schematic cross-sectional view seen in the axial direction for explaining another example of a cutting means used for cutting in the method for manufacturing an optical laminate with a cover glass of the present invention; Fig. 5 (b) is a schematic perspective view of the cutting means of Fig. 5 (a).

EMBODIMENT OF THE INVENTION Hereinafter, although specific embodiment of this invention is described with reference to drawings, this invention is not limited to these embodiment. In addition, in order to make it easy to see, the figure is shown typically, Moreover, ratio, angle, etc. of length, width|variety, thickness, etc. in a figure differ from reality.

A. Optical laminate

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic sectional drawing explaining the optical laminated body with a cover glass by one Embodiment of this invention. The optical laminate 100 with a cover glass of the illustrated example includes a cover glass 110 , a first pressure-sensitive adhesive layer 120 , an optical film 130 , and a second pressure-sensitive adhesive layer 140 in this order. Practically, the separator 150 is temporarily attached to the surface of the second pressure-sensitive adhesive layer 140 so that it can be peeled off. The optical laminated body with a cover glass of this invention can be applied suitably to the image display apparatus with a cover glass.

The optical laminated body with a cover glass which concerns on embodiment of this invention is cut-processed typically, Therefore, it contains a cut cross section, and can have a cut mark. As for the optical laminated body with a cover glass, the whole may be cut, and a part of the component may be cut. When a part of the component is cut, for example, a laminate of the optical film 130 and the second pressure-sensitive adhesive layer 140 (in practice, the separator 150) is cut, and the cut laminate is a first It may be bonded to the cover glass 110 via the pressure-sensitive adhesive layer 120 . In one embodiment, as shown in FIG. 2, the optical laminated body with a cover glass contains the recessed part 160, when the cut part is planar view. Since the occurrence of cracks in such concave portions is remarkable, according to the embodiment of the present invention, cracks can be favorably suppressed even in such concave portions.

As the optical film 130, any suitable optical film that can be used for applications requiring cutting processing can be mentioned. The optical film may be a film comprised from a single layer, or a laminated body may be sufficient as it. Specific examples of the optical film include a polarizer, a retardation film, a polarizing plate (typically, a laminate of a polarizer and a protective film), a conductive film for a touch panel, a surface treatment film, and a laminate suitably laminated according to the purpose (for example, Circularly polarizing plate for antireflection, Polarizing plate with conductive layer for touch panels) is mentioned. ADVANTAGE OF THE INVENTION According to embodiment of this invention, cracks can be suppressed remarkably especially in the optical laminated body with a cover glass which consists of an optical film which shrinks easily like a polarizer.

For example, when the optical film 130 is a polarizing plate, the polarizing plate may include a protective film only on the first adhesive layer 120 side of the polarizer, and may include a protective film only on the second adhesive layer 140 side of the polarizer. and protective films may be included on both sides. According to embodiment of this invention, the prevention effect of the crack of the protective film provided especially in the 1st adhesive layer side is remarkable. The protective film provided on the 1st adhesive layer side may be surface-treated, such as a hard-coat process, a reflection prevention process, a sticking prevention process, and an anti-glare process, as needed. In particular, a configuration in which a hard coat treatment is applied to the protective film provided on the first pressure-sensitive adhesive layer side tends to be relatively easily cracked. . It is preferable that the protective film provided in the 2nd adhesive layer side is optically isotropic in one Embodiment. As used herein, "optically isotropic" means that the in-plane retardation Re (550) is 0 nm to 10 nm, and the retardation Rth (550) in the thickness direction is -10 nm to +10 nm. The said protective film may serve also as retardation layer in another embodiment. As for the structure of the protective film as a retardation layer, any suitable structure may be employ|adopted according to the objective. For example, a λ/2 plate may be sufficient as a protective film, and a λ/4 plate may be sufficient as these, and these laminated bodies may be sufficient as them. The λ/2 plate and the λ/4 plate typically have a refractive index characteristic of nx > ny ≥ nz. The λ/2 plate preferably has an in-plane retardation Re (550) of 180 nm to 320 nm, and the λ/4 plate preferably has an in-plane retardation Re (550) of 100 nm to 200 nm. Further, for example, the protective film may be a laminate of a negative B plate (nx>ny>nz) and a positive C plate (nz>nx=ny). In this specification, 'Re(λ)' is an in-plane retardation measured with light having a wavelength of λ nm at 23°C. For example, 'Re(550)' is an in-plane retardation measured with light having a wavelength of 550 nm at 23°C. Re(λ) is obtained by the formula: Re(λ)=(nx-ny)×d when the thickness of the layer (film) is d(nm). 'Rth(λ)' is the retardation in the thickness direction measured with light having a wavelength of λnm at 23°C. For example, 'Rth (550)' is the retardation in the thickness direction measured with light having a wavelength of 550 nm at 23°C. Rth(λ) is obtained by the formula: Rth(λ)=(nx-nz)×d when the thickness of the layer (film) is d(nm). 'nx' is the refractive index in the direction in which the in-plane refractive index is maximum (ie, the slow axis direction), 'ny' is the refractive index in the direction orthogonal to the slow axis in the plane (ie, the fast axis direction), and 'nz' is It is the refractive index in the thickness direction.

A protective film is formed from arbitrary appropriate films which can be used as a protective film of a polarizer. Specific examples of the material used as the main component of the film include cellulose resins such as triacetyl cellulose (TAC), polyester, polyvinyl alcohol, polycarbonate, polyamide, polyimide, polyethersulfone, and polysulfone. Transparent resins, such as a phone type, polystyrene type, polynorbornene type, polyolefin type, (meth)acrylic type, acetate type, etc. are mentioned. Moreover, thermosetting resins, such as (meth)acrylic type, a urethane type, a (meth)acrylic urethane type, an epoxy type, silicone type, or ultraviolet curing resin, etc. are mentioned. In addition to this, for example, a glassy polymer such as a siloxane-based polymer may also be mentioned. Moreover, the polymer film described in Unexamined-Japanese-Patent No. 2001-343529 (WO01/37007) can also be used. As a material of this film, for example, a resin composition containing a thermoplastic resin having a substituted or unsubstituted imide group in a side chain and a thermoplastic resin having a substituted or unsubstituted phenyl group and a nitrile group in the side chain can be used, for example, isobutene and N- and a resin composition containing an alternating copolymer containing methylmaleimide and an acrylonitrile/styrene copolymer. The polymer film may be, for example, an extrusion molding of the resin composition.

In one embodiment, as for the protective film provided in the 1st adhesive layer side, break extension in 25 degreeC becomes like this. Preferably it is 2 mm or more, More preferably, it is 50 mm or more. The elongation at break may be, for example, 70 mm or less. If the breaking elongation of the protective film provided on the first adhesive layer side is within such a range, cracks in the protective film are caused by a synergistic effect with the effect of optimizing the relationship between the storage elastic modulus of the first adhesive layer and the second adhesive layer. This is significantly prevented. In addition, break elongation can be measured according to JISK7113.

The 1st adhesive layer 120 is typically used in order to bond a cover glass and an optical film together. The first pressure-sensitive adhesive layer 120 may be composed of any suitable pressure-sensitive adhesive as long as the storage elastic modulus (G1') at -40°C becomes a desired range to be described later. The first pressure-sensitive adhesive layer 120 may be typically made of a rubber-based pressure-sensitive adhesive (rubber-based pressure-sensitive adhesive composition). The rubber-based pressure-sensitive adhesive composition may typically include a butadiene polymer and/or a polyisoprene polymer (or a modified product thereof) and a photopolymerization initiator. The rubber-based pressure-sensitive adhesive composition includes polystyrene, polyurethane (eg, isophorone diisocyanate as a raw material), polyurethane acrylate, polyisoprene-based acrylate or an ester thereof, terpene-based hydrogenated resin, reactive acrylic monomer (eg, 2 -Hydroxybutyl methacrylate, 4-hydroxyethyl acrylate, 2-ethylhexyl acrylate, dodecyl acrylate, isobornyl acrylate), reactive methacrylic monomers (eg, dicyclopentenyloxyethyl methacrylic) rate) and the like may be further included. The rubber-based pressure-sensitive adhesive composition may further include a silane coupling agent. As a silane coupling agent, an epoxy-group containing silane coupling agent is mentioned, for example. In addition, the rubber-based pressure-sensitive adhesive composition preferably does not contain a hydrocarbon component (eg, heptane). The thickness of the first pressure-sensitive adhesive layer may be, for example, 10 μm to 50 μm.

The 2nd adhesive layer 140 is typically used in order to bond the finally obtained optical laminated body with a cover glass to a display cell. The second pressure-sensitive adhesive layer 140 may be typically made of an acrylic pressure-sensitive adhesive (acrylic pressure-sensitive adhesive composition). The acrylic pressure-sensitive adhesive composition typically contains a (meth)acrylic polymer as a main component. The (meth)acrylic polymer may be contained in the pressure-sensitive adhesive composition in a proportion of, for example, 50% by weight or more, preferably 70% by weight or more, more preferably 90% by weight or more of the solid content of the pressure-sensitive adhesive composition. The (meth)acrylic polymer contains an alkyl (meth)acrylate as a main component as a monomer unit. In addition, (meth)acrylate refers to an acrylate and/or a methacrylate. Examples of the alkyl group of the alkyl (meth)acrylate include a linear or branched alkyl group containing 1 to 18 carbon atoms. The average number of carbon atoms in the alkyl group is preferably 3 to 9. Examples of the monomer constituting the (meth)acrylic polymer include, in addition to the alkyl (meth)acrylate, a carboxy group-containing monomer, a hydroxyl group-containing monomer, an amide group-containing monomer, and an aromatic ring-containing (meth)acrylate. The acrylic pressure-sensitive adhesive composition may preferably contain a silane coupling agent and/or a crosslinking agent. As a silane coupling agent, an epoxy-group containing silane coupling agent is mentioned, for example. As a crosslinking agent, an isocyanate type crosslinking agent and a peroxide type crosslinking agent are mentioned, for example. The thickness of the second pressure-sensitive adhesive layer may be, for example, 10 μm to 50 μm. Details of the second pressure-sensitive adhesive layer or the acrylic pressure-sensitive adhesive composition are described in, for example, Japanese Patent Application Laid-Open No. 2016-190996, the description of which is incorporated herein by reference.

In the embodiment of the present invention, the ratio G ₁ of the storage elastic modulus (G1') at -40°C of the first pressure-sensitive adhesive layer 120 and the storage elastic modulus at -40°C (G2') of the second pressure-sensitive adhesive layer 140 (G2'). '/G2' is ₁ or more, Preferably it is 3 or more, More preferably, it is 20 or more. When ratio G1'/G2' is ₁ or _more , the crack (substantially, the crack of an optical film: the crack after a heat cycle test in particular) in a polarizing plate with a cover glass can be suppressed favorably. Meanwhile, the ratio G ₁ ′/G ₂ ′ may be, for example, 300 or less. In more detail, it is as follows. When the storage elastic modulus of the first pressure-sensitive adhesive layer is low (soft), the movement of contraction of the polarizer cannot be suppressed, and cracks may occur in the protective film on the first adhesive layer side (protective film on the visual side of the polarizer). (The storage modulus of the first pressure-sensitive adhesive layer will be described later). According to the embodiment of the present invention, the dimensional change of the polarizer is suppressed by increasing the storage elastic modulus of the first pressure-sensitive adhesive layer (hardening, as a result, G ₁ '/G ₂ '>1), and the first pressure-sensitive adhesive It can suppress that a crack arises in the protective film by the side of a layer. In another embodiment, the ratio G ₁ '/G ₂ ' may be about 1-2. By making small the difference of the storage elastic modulus of a 1st adhesive layer and a 2nd adhesive layer, it moves vertically with respect to shrinkage|contraction of a polarizer similarly, and generation|occurrence|production of distortion can be suppressed.

The storage modulus (G1') at -40°C of the first pressure-sensitive adhesive layer is preferably 5.0×10 ⁶ (Pa) or more, more preferably 1.0×10 ⁷ (Pa) or more, still more preferably 1.0× 10 ⁸ (Pa) or more, particularly preferably 1.5×10 ⁸ (Pa) or more. The storage modulus G1 ′ may be, for example, 5.0×10 ⁹ (Pa) or less. When the storage elastic modulus (G1') is so large (the first pressure-sensitive adhesive layer is hard), and the ratio G ₁ '/G ₂ ' satisfies the above relationship, cracks in the polarizing plate with cover glass are further improved can be suppressed

The storage modulus (G2') at -40°C of the second pressure-sensitive adhesive layer is preferably 1.0×10 ⁵ (Pa) or more, more preferably 1.0×10 ⁷ (Pa) or more, and still more preferably 1.0×10 5 (Pa) or more. 10 ⁸ (Pa) or more, particularly preferably 1.0×10 ⁸ (Pa) or more. The storage modulus G2' may be, for example, 1.0×10 ⁹ (Pa) or less. If storage elastic modulus (G2') is such a range _, it is easy to make ratio G1'/G2' into _a desired value.

For the cover glass 110 , a configuration well known in the industry may be employed, and thus a detailed description thereof will be omitted.

B. Manufacturing method of optical laminate with cover glass

Hereinafter, each process in the manufacturing method of a planar optical laminated body with a cover glass as shown in FIG. 2 as an example is demonstrated. In the example of illustration, embodiment in which the laminated body (henceforth an optical laminated body) of an optical film and a 2nd adhesive layer (practically a separator) is provided for cutting is demonstrated.

B-1. formation of work

3 : is a schematic perspective view for demonstrating a cutting process, and the workpiece|work 1 is shown in this figure. As shown in FIG. 3, the workpiece|work 1 which laminated|stacked the optical laminated body several sheets is formed. The optical laminate is typically cut into any suitable shape at the time of forming the work. Specifically, the optical laminate may be cut into a rectangular shape, may be cut into a shape similar to a rectangular shape, or may be cut into an appropriate shape (eg, circular) according to the purpose. In the illustrated example, the optical laminate is cut into a rectangular shape, and the work 1 includes outer peripheral surfaces (cut surfaces) 1a and 1b facing each other and outer peripheral surfaces (cut surfaces) 1c and 1d orthogonal to them. are doing The work 1 is preferably clamped from the top and bottom by clamping means (not shown). The total thickness of the work is preferably 8 mm to 20 mm, more preferably 9 mm to 15 mm, still more preferably about 10 mm. With such a thickness, it is possible to prevent damage caused by pressure by clamping means or by impact during cutting. The optical laminated body is superimposed so that a workpiece|work may have such a total thickness. The number of optical laminates constituting the work may be, for example, 10 to 50 sheets. The clamping means (eg, jig) may be made of a soft material or a hard material. When composed of a soft material, its hardness (JIS A) is preferably 60° to 80°. When hardness is too high, the impression by a clamping means may remain. When hardness is too low, a position shift may arise by deformation|transformation of a jig|tool, and cutting precision may become inadequate.

B-2. cutting

Next, the outer peripheral surface of the work 1 is cut by the cutting means 20 . Cutting is performed by bringing the cutting edge of the cutting means into contact with the outer peripheral surface of the work 1 . The cutting may be performed over the entire circumference of the outer peripheral surface of the work, or may be performed only at a predetermined position. When producing a planar optical laminate as shown in Fig. 2, cutting is typically performed over the entire circumference of the outer peripheral surface of the work. For example, after cutting is performed over the entire periphery of the outer peripheral surface of the work, cutting for forming the concave portion may be further performed. Cutting is typically so-called end milling, as shown in FIGS. 3 to 5 . That is, the outer peripheral surface of the work 1 is cut using the side surface of the cutting means (end mill) 20 . As the cutting means (end mill) 20, a straight end mill can be typically used.

As shown in FIGS. 4 and 5 , the end mill 20 includes a rotating shaft 21 extending in the stacking direction (vertical direction) of the work 1 and a main body rotating about the rotating shaft 21 as the center. and a cutting edge 22 configured as an outer diameter. The cutting edge 22 may be configured as an outermost diameter twisted along the rotating shaft 21 as shown in FIG. 4 (a predetermined twist angle may be included), and as shown in FIG. 5 , substantially to the rotating shaft 21 may be configured to extend in a direction parallel to . In addition, '0°' means substantially 0°, and includes a case where the angle is slightly twisted due to a processing error or the like. When the cutting edge includes a predetermined twist angle, the twist angle is preferably 70° or less, more preferably 65° or less, and still more preferably 45° or less. The cutting edge 22 includes a blade tip 22a, a cutting surface 22b, and an escape surface 22c. The number of blades of the cutting edge 22 can be appropriately set as long as a desired number of contacts, which will be described later, is obtained. The number of blades in Fig. 4 is 3 and the number of blades in Fig. 5 is 2, but the number of blades may be 1, 4, or 5 or more. Preferably, the number of blades is two. If it is such a structure, the rigidity of a blade is ensured, and a pocket is ensured and it can discharge|emit a cutting chip favorably.

In one embodiment, the HV hardness of the cutting edge 22 is 1500 or more typically, Preferably it is 1700 or more, More preferably, it is 2000 or more. The upper limit of the HV hardness may be, for example, 2350. In this case, the cutting edge is typically made of cemented carbide. Cemented carbide is typically obtained by sintering powder of metal carbide. Specific examples of the cemented carbide include WC-Co-based alloys, WC-TiC-Co-based alloys, WC-TaC-Co-based alloys, and WC-TiC-TaC-Co-based alloys. In addition, HV hardness is also called Vickers hardness, and can be measured according to JIS Z 2244.

In another embodiment, the HV hardness of the cutting edge 22 is typically 7000 or more, Preferably it is 8000 or more, More preferably, it is 9000 or more, More preferably, it is 10000 or more. The upper limit of the HV hardness may be, for example, 15000. In this case, the cutting edge typically comprises sintered diamond. More specifically, the cutting edge is formed with a sintered diamond layer on a base made of cemented carbide. Sintered diamond (PCD: Polycrystalline diamond) refers to polycrystalline diamond obtained by baking small particles of diamond together with powder of metal and/or ceramic at high temperature and pressure.

Conditions for cutting may be appropriately set according to the purpose. For example, by appropriately adjusting the feed rate, the number of rotations, the number of blades, etc. of the end mill, even an optical laminate including an adhesive layer can be satisfactorily cut. In this specification, 'feed speed' means the relative speed of the cutting means (end mill) and the work. Accordingly, in cutting, only the end mill may be moved, only the work may be moved, or both the end mill and the work may be moved. The number of cuts may be 1 cut, 2 cuts, 3 cuts or more. In one embodiment, the diameter of the end mill 20 is preferably between 3 mm and 20 mm.

As mentioned above, the optical laminated body by which the cutting process was carried out can be obtained. Moreover, the optical laminated body (substantially, an optical film and an adhesive layer) processed by cutting may have a cutting mark typically.

An optical laminate with a cover glass can be obtained by bonding the obtained optical laminated body to a cover glass through a 1st adhesive layer.

Although the embodiment in which the optical laminated body is provided for cutting was described in the example of illustration, it goes without saying that the optical laminated body with a cover glass may be provided for cutting.

C. Image display device with cover glass

The optical laminate with a cover glass according to an embodiment of the present invention (for example, the optical laminate with a cover glass according to the above items A to B) can be suitably applied to an image display apparatus with a cover glass as described above. Therefore, an image display apparatus with a cover glass is also included in embodiment of this invention. An image display apparatus with a cover glass contains a display cell and the optical laminated body with a cover glass which concerns on embodiment of this invention arrange|positioned on the visual recognition side of a display cell.

Examples of the image display device include a liquid crystal display device, an organic electroluminescent (EL) display device, and a quantum dot display device.

Example

Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited to these Examples. The evaluation items in the Examples are as follows.

(1) crack

About the polarizing plate with cover glass obtained by the Example and the comparative example, the heat cycle (heat shock) test of 200 cycles was done at -40 degreeC - 85 degreeC. About the occurrence of cracks after the test, the transmitted light test was performed in a state in which the polarizing filter was arranged so as to cross the absorption axis of the polarizer of the polarizing plate, and the following criteria evaluated.

Yes: light leakage can be recognized

None: light leakage cannot be recognized

The said evaluation was performed 3 samples at a time for every polarizing plate with a cover glass obtained by the Example and the comparative example. The number of samples in which cracks occurred among the three samples was defined as the frequency of occurrence of cracks (F/3pcs). In addition, using an optical microscope, the crack size was measured in transmission observation at a magnification of 50 times, and the size of the largest crack was defined as the crack size (㎛).

<Example 1>

According to a conventional method, in order from the visual side, surface protection film (48 µm)/hard coat layer (5 µm)/cycloolefin-based protective film (47 µm)/polarizer (5 µm)/cycloolefin-based protective film (24) A polarizing plate with a pressure-sensitive adhesive layer having the structure of µm)/second pressure-sensitive adhesive layer (20 µm)/separator was produced. The second pressure-sensitive adhesive layer was prepared according to [0121] and [0124] of Japanese Patent Application Laid-Open No. 2016-190996. The storage elastic modulus (G2') in -40 degreeC of the 2nd adhesive layer was 5.0x10 ⁶ (Pa). The obtained polarizing plate with a pressure-sensitive adhesive layer was punched into a shape similar to that of Fig. 2 (a rectangular shape with an approximate size of 142.0 mm x 66.8 mm, a shape not including a concave portion), and a plurality of punched polarizing plates with an pressure-sensitive adhesive layer were stacked over a work piece (total thickness of about 10 mm) ) was made. In the state which clamped the obtained workpiece|work with the clamp (jig), while cutting the peripheral part by end milling, the recessed part was formed, and the cut-processed polarizing plate with an adhesive layer as shown in FIG. 2 was obtained. The cutting edge of the end mill was sintered diamond, and the HV hardness was 10000. In addition, the number of blades of the end mill was 2, and the twist angle was 0 degree. In addition, the feed rate of the end mill (feed rate when cutting the straight part) was 1000 mm/min, the number of revolutions was 25000 rpm, and the number of cuts was 2 times (0.1 mm for the first time, 0.3 mm for a cutting allowance of 0.2 mm for the second).

The surface protection film of the said polarizing plate with an adhesive layer was peeled, and the 1st adhesive layer was formed in the peeling surface. The first pressure-sensitive adhesive layer was prepared according to [0053] of Japanese Patent Application Laid-Open No. 2016-103030. The storage modulus (G1') at -40°C of the first pressure-sensitive adhesive layer was 1.7×10 ⁸ (Pa). The polarizing plate with an adhesive layer was bonded to the Matsunami Glass Industry cover glass through the formed 1st adhesive layer, and the polarizing plate with a cover glass (optical laminated body with a cover glass) was obtained. Furthermore, the separator temporarily attached to the 2nd adhesive layer was peeled, the glass plate was bonded to the 2nd adhesive layer, and it used for evaluation of the said crack. A result is shown in Table 1.

<Examples 2 to 8 and Comparative Examples 1 to 5>

By changing the prescription of the pressure-sensitive adhesive composition constituting the first pressure-sensitive adhesive layer, the storage elastic modulus (G1 ') at -40 ° C. as shown in Table 1, by changing the prescription of the pressure-sensitive adhesive composition constituting the second pressure-sensitive adhesive layer - The storage modulus (G2') at 40°C was as shown in Table 1, and in Examples 7 to 8 and Comparative Examples 2 to 5, the angle of twist of the cutting edge of the end mill was set to 30°. It carried out similarly to 1, and as shown in FIG. 2, the polarizing plate with a cover glass by which the cutting process was carried out was obtained. About the obtained cutting-processed polarizing plate with a cover glass, it carried out similarly to Example 1, and evaluated the crack. A result is shown in Table 1. In addition, the 1st adhesive layer in each Example and a comparative example was produced according to description of the following publication.

Example 2: [0100] and [0110] of Japanese Patent Application Laid-Open No. 2011-175247

Example 3: (E) of [0085] of Japanese Unexamined Patent Publication No. 2017-075998

Example 4: [0103] of Japanese Unexamined Patent Publication No. 2014-156552

Example 5: [0121] and [0124] of Japanese Patent Application Laid-Open No. 2016-190996

Example 6: [0065] of Japanese Patent Laid-Open No. 2016-066074

Example 7: Same as Example 1

Example 8: Same as Example 5

Comparative Example 1: Table 1 of [0048] of Japanese Patent Application Laid-Open No. 2012-046658 (Example 1)

Comparative Example 2: [0149], [0150] and [0153] of Japanese Patent Publication No. 5038224 (Example 1)

Comparative Example 3: Same as Example 1

Comparative Example 4: Same as Comparative Example 1

Comparative Example 5: Same as Comparative Example 1

The 2nd adhesive layer in each Example and a comparative example was produced according to description of the following publication.

Example 2: Same as Example 1

Example 3: Same as Example 1

Example 4: Same as Example 1

Example 5: Same as Example 1

Example 6: Same as Example 1

Example 7: Same as Example 1

Example 8: [0149], [0150] and [0153] of Japanese Patent Publication No. 5038224 (Example 1)

Comparative Example 1: Same as Example 1

Comparative Example 2: Same as Example 1

Comparative Example 3: [0135] and [0136] of Japanese Patent Publication No. 4820443 (Example 1)

Comparative Example 4: Same as Example 8

Comparative Example 5: Same as Example 1

[Table 1]

Industrial Applicability

The optical laminated body with cover glass of this invention is used suitably when providing a cover glass in an image display part, In particular, a rectangular image display part typified by a personal computer (PC) and a tablet terminal, and/or an instrument panel of an automobile, It can be suitably used in a heterogeneous image display unit typified by a smart watch.

1: work
20: cutting means
100: optical laminate with cover glass
110: cover glass
120: first pressure-sensitive adhesive layer
130: optical film
140: second pressure-sensitive adhesive layer
150: separator
160: recess

Claims (9)

A cover glass, a first pressure-sensitive adhesive layer, an optical film, and a second pressure-sensitive adhesive layer comprising in this order,
The ratio G ₁ '/G ₂ ' of the storage elastic modulus at -40°C of the first pressure-sensitive adhesive layer (G1') and the storage elastic modulus at -40°C (G2') of the second pressure-sensitive adhesive layer is 1 or more,
An optical laminate with a cover glass. According to claim 1,
The optical laminate with a cover glass whose storage elastic modulus (G1') in -40 degreeC of the said 1st adhesive layer is 5.0x10 ⁶ (Pa) or more. According to claim 1,
An optical laminate with a cover glass including at least the optical film and the second pressure-sensitive adhesive layer having a cut cross section having a cut mark. 4. The method of claim 3,
The optical laminate with a cover glass, wherein the cut-out portion includes a concave portion when viewed in plan. According to claim 1,
The optical laminated body with a cover glass in which the said optical film contains a polarizer. 6. The method of claim 5,
The optical laminated body with a cover glass in which the said optical film further contains a protective film on the said 1st adhesive layer side of the said polarizer. 7. The method of claim 6,
The optical laminate with a cover glass in which the hard-coat layer is formed in the said protective film. 7. The method of claim 6,
The optical laminate with a cover glass whose break elongation in 25 degreeC of the said protective film is 2 mm or more. The image display apparatus with a cover glass containing a display cell and the optical laminated body with a cover glass in any one of Claims 1-8 arrange|positioned at the visual recognition side of the said display cell.

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