TWI840412B - Image display panel with frame and image display device - Google Patents

Abstract

The image display panel with a frame of the present invention is provided with an outer frame of a narrow frame on the image display panel via an elastic intermediate layer. The image display panel has a polarizing film disposed on the visual side of the image display portion through an adhesive layer; the distance between the outermost surface of the visual side of the image display panel and the adhesive layer is more than 75 μm; the adhesive layer is formed by the following adhesive composition: the adhesive composition contains (methyl) The acrylic polymer (A) contains a silane coupling agent (B) and does not contain a polyether compound having a polyether skeleton and a reactive silyl group, wherein the (meth)acrylic polymer (A) contains 80% by mass or more of a predetermined monomer (a) as a monofunctional monomer unit, and the predetermined monomer (a) contains 20% by mass or more of n-butyl acrylate or 70% by mass or more of an alkoxyalkyl (meth)acrylate. The present invention can suppress peeling of the adhesive layer even in a humidified environment where a grease or emulsifiable concentrate component is in contact with the elastic intermediate layer.

Description

Image display panel with frame and image display device

The present invention relates to an image display panel with a frame as an outer frame on the outer side of the image display panel. The image display panel with the frame can form an image display device such as a liquid crystal display device (LCD), an organic EL display device, etc.

Invention background

Image display panels such as liquid crystal display panels have polarizing films arranged on the image display portion such as liquid crystal cells due to their image forming method. Generally speaking, in image display panels, at least a polarizing film is attached to the image display portion through an adhesive layer.

The adhesive layer is usually formed by using an adhesive containing a base polymer and a crosslinking agent. The base polymer is an acrylic adhesive using an acrylic polymer. The adhesive is required to have re-peelability (reworkability) so that when the polarizing film is bonded to the image display part, it can be easily peeled off even if there is an error in the bonding position or a foreign object is bitten into the bonding surface. In addition, in addition to requiring reworkability, the adhesive layer is also required to improve whitening (peripheral unevenness) or improve durability, and as an adhesive composition that can improve the above characteristics, there is a document that proposes mixing a polyether compound with a reactive silicon group into an acrylic polymer (Patent Document 1).

In addition, the outer side of the aforementioned image display panel usually has a frame (outer frame) from the perspective of handling. In recent years, there has been a trend to narrow the frame due to emphasis on design (Patent Documents 2, 3).

Prior art literature Patent Literature

Patent document 1: Japanese Patent Publication No. 2010-275522

Patent document 2: Japanese Patent Publication No. 2012-014000

Patent document 3: Japanese Patent Publication No. 2016-004214

Summary of invention

When the image display panel with a narrow frame is used in an image display device such as a mobile phone, a cover glass or the like is disposed on the outermost surface of the image display panel. However, when it is used in an openable image display device such as a notebook computer, a cover glass or the like is usually not disposed on the outermost surface of the image display panel, so the strength of the visual side surface of the image display panel is not sufficient. As a countermeasure, an elastic body is disposed on the upper part of the frame, for example, in order to prevent the image display panel from directly contacting the image display device body when the laptop computer is closed. However, when the frame has been narrowed, it is sometimes difficult to dispose the elastic body on the upper part of the frame. Therefore, when using a narrow frame, the following aspect is also considered: a flexible middle layer protruding more than the outermost surface of the viewing side of the image display panel is provided between the end surface of the image display panel and the frame.

Generally speaking, when turning on and off the image display panel of a laptop computer, the outer edge of the image display panel is often touched with bare hands. Bare hands contain oil components (oleic acid, etc.) derived from sebum, and after using moisturizers, sunscreens, etc., these cream components may remain on bare hands. It is known that in this case, if a laptop computer with a framed image display panel provided with the above-mentioned elastic intermediate layer is turned on and off with bare hands, the above-mentioned oil or cream components may directly or indirectly reach the adhesive layer that adheres the polarizing film, etc. to the image display part through the above-mentioned elastic intermediate layer, thereby causing the above-mentioned adhesive layer to absorb the above-mentioned components and expand. Especially in a humidified environment, the adhesive layer that absorbs the aforementioned components will swell more easily, and there is a problem that the aforementioned adhesive layer peels off from the image display part. However, the adhesive layer formed by the adhesive composition described in the above-mentioned patent document 1 cannot solve the aforementioned peeling problem.

The purpose of the present invention is to provide an image display panel with a border frame, wherein the image display panel with a border frame is provided with an outer border frame of a narrow border frame through an elastic middle layer, and the image display panel has an image display portion and a polarizing film disposed on the visual side of the image display portion through an adhesive layer; even when the image display panel with a border frame is placed in a humidified environment in a state where grease or emulsion components have contacted the elastic middle layer, the adhesive layer can still be prevented from peeling off.

Furthermore, the present invention aims to provide an image display device using an image display panel with the aforementioned attached frame.

As a result of repeated efforts to solve the above-mentioned problems, the inventors of the present invention have found that the above-mentioned problems can be solved by the following image display panel with a border, etc., and thus completed the present invention.

That is, the present invention relates to an image display panel with a frame, which is characterized in that: it has an image display panel, an elastic middle layer and an external frame, the image display panel has an image display portion and an optical film arranged on the visual side of the image display portion through an adhesive layer, and the elastic middle layer is arranged at least a portion of the outer side of the end surface of the image display panel, and is more protruding than the outermost surface of the visual side of the image display panel, and has a width of less than 5 mm, the external frame is arranged more outward than the elastic middle layer and does not cover the elastic middle layer, and has a width of less than 5 mm; the optical film has a polarizing film; the distance between the outermost surface of the visual side of the image display panel and the adhesive layer is 75 μm. m or more; the adhesive layer is formed by the following adhesive composition: the adhesive composition contains a (meth) acrylic polymer (A) as a base polymer, the (meth) acrylic polymer (A) contains 80% by mass or more of a monomer (a) as a monofunctional monomer unit, the monomer (a) is selected from any one of a (meth) acrylic acid alkyl ester having an alkyl group of 1 to 4 carbon atoms, a (meth) acrylic acid alkoxyalkyl ester, a fluorine-containing monomer and acrylonitrile, and contains 20% by mass or more of n-butyl acrylate or 70% by mass or more of a (meth) acrylic acid alkoxyalkyl ester as a monofunctional monomer unit, contains a silane coupling agent (B), and does not contain a polyether compound having a polyether skeleton and a reactive silicon group at at least one end.

In the aforementioned image display panel with a border, the aforementioned polarizing film preferably has a transparent protective film on one or both sides of the polarizing element, and the aforementioned polarizing element preferably has a thickness of 3 to 30 μm .

In the aforementioned image display panel with a border, the aforementioned optical film is preferably one having a surface treatment layer on the outermost surface of the viewing side.

In the aforementioned image display panel with a border frame, the distance between the outermost surface of the viewing side of the aforementioned image display panel and the aforementioned adhesive should be less than 300 μm .

In the aforementioned image display panel with border, the thickness of the aforementioned adhesive layer is preferably 10-30 μm .

In the aforementioned image display panel with border, the aforementioned adhesive layer is also suitable for the case where the oleic acid swelling degree is greater than 130% and less than 190%.

The aforementioned image display panel with a frame can be used in a state where the end surface of the aforementioned image display panel is in contact with the aforementioned elastic middle layer.

The image display panel with a border can be used in the following manner: in the end portion of the image display panel, an inner border is provided on the outermost surface which is further inward than the elastic middle layer, and the elastic middle layer protrudes more than the inner border.

The aforementioned image display panel with borders can be used in which the aforementioned monomers (a) are all the aforementioned (meth) alkyl acrylates having an alkyl group with 1 to 4 carbon atoms, and the aforementioned monomer units contain 30% by mass or more of n-butyl acrylate (aspect (1)).

It can be used: In the above-mentioned aspect (1), the aforementioned (meth) alkyl acrylate having an alkyl group with 1 to 4 carbon atoms is all n-butyl acrylate, and the aforementioned monomer unit contains 70% by mass or more of n-butyl acrylate (aspect (10)).

It is also possible to use: In the above aspect (10), the aforementioned (meth)acrylic acid alkyl ester having an alkyl group with 1 to 4 carbon atoms contains (meth)acrylic acid alkyl ester having an alkyl group with 1 to 4 carbon atoms (except for n-butyl acrylate) and n-butyl acrylate (aspect (11)).

And it can be used: In the above aspect (11), as the aforementioned monomer unit, the one containing 4 to 60% by mass of the aforementioned (meth) alkyl acrylate having an alkyl group with 1 to 4 carbon atoms (except for n-butyl acrylate) and 30% by mass or more of n-butyl acrylate.

Furthermore, the above-mentioned aspect (11) may be used, wherein the monomer unit contains 15-60% by mass of the above-mentioned alkyl acrylate having an alkyl group with 1-4 carbon atoms (except n-butyl acrylate) and 30% by mass or more of n-butyl acrylate (aspect (11A)).

Furthermore, the above-mentioned aspect (11) may be used, wherein the monomer unit contains 5-15% by mass of the above-mentioned alkyl methacrylate having an alkyl group with 1-4 carbon atoms and 70% by mass or more of n-butyl acrylate (aspect (11B)).

In addition, the image display panel with borders may include: the monomer (a) contains the alkyl (meth)acrylate with 1 to 4 carbon atoms and the fluorine-containing monomer, and the monomer unit contains 30% by mass or more of the alkyl (meth)acrylate with 1 to 4 carbon atoms and 25% by mass or more of the fluorine-containing monomer, and contains 30% by mass or more of n-butyl acrylate (Aspect (21)).

Furthermore, the image display panel with borders may use: The aforementioned monomer (a) contains the aforementioned (meth) acrylate alkyl ester with a carbon number of 1 to 4 and acrylonitrile, and the aforementioned monomer unit contains 70% by mass or more of the aforementioned (meth) acrylate alkyl ester with a carbon number of 1 to 4 and 5% by mass or more of acrylonitrile, and contains 70% by mass or more of n-butyl acrylate (Aspect (22)).

Furthermore, the aforementioned image display panel with borders may contain the aforementioned monomer (a) containing 70% by mass or more of the aforementioned alkoxyalkyl (meth)acrylate (aspect (23)).

In the aforementioned image display panel with border, the aforementioned silane coupling agent (B) is preferably at least one selected from an epoxy-containing silane coupling agent (b1) and a silane coupling agent (b2) containing a silane group. The aforementioned epoxy-containing silane coupling agent (b1) is preferably a low molecular weight epoxy-containing silane coupling agent (b1). Moreover, the aforementioned silane coupling agent (b2) containing a silane group is preferably an oligomer type silane coupling agent (b2) containing a silane group.

Furthermore, the present invention relates to a liquid crystal display device having an image display panel with the aforementioned border.

The image display panel with a frame of the present invention has a structure in which an outer frame with a narrow frame is provided on the image display panel via an elastic middle layer. By setting the distance between the outermost surface of the visual side of the aforementioned image display panel and the adhesive layer attached to the visual side of the image display portion to be above a predetermined range, even if oil or emulsion components have already contacted the aforementioned elastic middle layer, the aforementioned components can still be prevented or prevented to a certain extent from reaching and contacting the aforementioned adhesive layer. Furthermore, in the image display panel with a border of the present invention, the adhesive layer is formed by an adhesive layer containing an acrylic polymer as a base polymer and a silane coupling agent, and the acrylic polymer uses a predetermined monomer with a predetermined ratio or more, so even in a humidified environment where a grease or emulsion component is in contact with the elastic intermediate layer, the adhesive layer can still be suppressed from peeling off.

1: Image display unit

2: Optical films (including polarizing films)

3: Adhesive layer (image display side)

4: Elastic middle layer

5: External border

6: Inner border

7: Empty room

8: Adhesive layer (covering the glass side)

9: Cover with glass

41:Maintenance Department

42: convex part

A: Image display panel

a: The most superficial

S: Gap

t: distance

FIG. 1A is a partial cross-sectional view showing an example of an image display panel with a frame according to the present invention.

FIG. 1B is a top view of an example of an image display panel with a frame of the present invention shown in FIG. 1A .

FIG. 2A is a partial cross-sectional view showing an example of an image display panel with a frame according to the present invention.

FIG. 2B is a top view showing an example of an image display panel with a frame of the present invention shown in FIG. 2A .

FIG. 3A is a partial cross-sectional view showing an example of an image display panel with a frame according to the present invention.

FIG. 3B is a top view showing an example of an image display panel with a frame of the present invention shown in FIG. 3A .

FIG4 is a top view showing an example of a frame-shaped elastic middle layer.

FIG5 is a partial cross-sectional view showing an example of an image display panel with a frame as a comparative example.

The form used to implement the invention

The present invention is described below with reference to the drawings.

The image display panel with a border of the present invention is shown in the cross-sectional view of FIG1A, and has an image display panel A and an external border 5 located on the outer side of the end surface of the aforementioned image display panel A. The image display panel A has an image display portion 1 and an optical film 2, and the optical film 2 is arranged on the visual side of the image display portion 1 through an adhesive layer 3. FIG1A is a part of a cross-sectional view of an example of an image display panel with a border, showing the end edge portion of one side. FIG1B is a top view of the image display panel with a border of the present invention. The external border 5 is arranged via an elastic intermediate layer 4. The elastic intermediate layer 4 is arranged to protrude more than the outermost surface a of the visual side of the aforementioned image display panel A (optical film 2), and the external border 5 is arranged not to cover the elastic intermediate layer 4. From the perspective of narrowing the frame and expanding the display area, or preventing the penetration of moisture, grease or emulsion components, and preventing cracks from occurring at the ends of the image display panel after the overall thickness of the image display device is thinned, it is suitable to use the image display panel A in a state where the end surface is in contact with the elastic middle layer 4. The outer frame 5 can be fixed to the elastic middle layer 4 by an adhesive.

On the other hand, from the viewpoint of simplifying the manufacturing steps of embedding the panel into the frame, a gap S can be provided between the end face of the image display panel A and the elastic intermediate layer 4 as shown in FIG2A. FIG2B is a top view of the image display panel with a border frame of the present invention. The gap S is preferably designed within a range of less than 2000 μm . When the gap S is provided, moisture, grease or emulsion components can easily penetrate into the gap S, but when the image display panel with a border frame of the present invention is used, the peeling of the adhesive layer can be suppressed even when placed in a humidified environment. Regardless of whether there is a gap S or not, the end face of the optical film 2 can be coated with an acrylic resin, a urethane resin, a polysilicone resin, a fluorine resin, or the like.

In addition, as shown in the cross-sectional view of FIG3A, the image display panel with a frame of the present invention can be provided with an inner frame 6 in the end face of the image display panel A, on the outermost surface a which is further inward than the elastic middle layer 4 in the embodiment shown in FIG1A or FIG1B. FIG3B is a top view of the image display panel with a frame of the present invention. In this embodiment, the elastic middle layer 4 is also used in an embodiment which is more protruding than the inner frame 6. In the embodiment shown in FIG3A, a case where a space 7 is provided between the end face of the image display panel A and the elastic middle layer 4 is illustrated, but in the embodiment shown in FIG3A, the image display panel can also be used in an embodiment where the end face of the image display panel A is in contact with the elastic middle layer 4. When the empty chamber 7 is provided in the state shown in FIG. 3A, accessories (camera lens, cable, dimming sensor, facial recognition sensor, etc.) can be arranged in the empty chamber 7, and the inner frame 6 above it can be used to perform its functions. The inner frame 6 can be fixed to the outermost surface a of the aforementioned image display panel A and the aforementioned elastic middle layer 4 by means of an adhesive.

In the image display panel with a frame of the present invention, the distance t between the outermost surface a of the visual side of the image display panel A (optical film 2) and the adhesive layer 3 is set to be greater than 75 μm . If the distance t is less than 75 μm , it will be difficult to suppress the peeling of the adhesive layer 3 in a humidified environment where there is a risk of contact between grease or emulsion components and the elastic intermediate layer. In order to suppress the peeling of the adhesive layer 3, the distance t is preferably greater than 100 μm , and more preferably greater than 120 μm . On the other hand, if the aforementioned distance t becomes longer (that is, if the thickness of the optical film becomes thicker), the dimensional shrinkage of the optical film in a humidified environment will become larger, and it will tend to warp easily. Therefore, the aforementioned distance t is preferably less than 300 μm , and more preferably less than 250 μm .

Furthermore, from the perspective of narrowing the frame of the image display panel with a frame, the widths of the external frame 5 and the elastic middle layer 4 should both be small. The widths of the external frame 5 and the elastic middle layer 4 are appropriately set according to the size of the image display panel A. Generally speaking, the width of the external frame 5 is less than 5 mm, preferably 0.5~5 mm, and preferably 0.5~3 mm. The width of the elastic middle layer 4 is less than 5 mm, preferably 0.5~5 mm, and preferably 0.5~3 mm. Furthermore, regarding the internal frame 6, from the perspective of narrowing the frame, it should also be small. Generally speaking, the width of the internal frame 6 should be 1~20 mm, and 1~15 mm is better. Furthermore, when the empty chamber 7 is provided, its width should be 1~20 mm, and 1~15 mm is better. When there is an inner frame 6, even when the grease or emulsion component contacts the elastic intermediate layer 4, the possibility of the component reaching and contacting the adhesive layer 3 will still be reduced, so the width of the cavity 7 is preferably greater than 1 mm.

Furthermore, the elastic middle layer 4 is used in a state where it protrudes more than the outermost surface a of the visual side of the image display panel A (optical film 2) in the state shown in the above FIG. 1A, and is used in a state where it protrudes more than the inner frame 6 in the state shown in the above FIG. 3A. By protruding, the image display panel and the body of the image display device can be prevented from directly contacting. The height of the protruding portion is generally preferably 0.5 to 5 mm, and 0.5 to 3 mm is more preferred. Furthermore, the elastic middle layer 4 is provided on the entire outer side of the end surface of the image display panel A in the top view shown in the above FIG. 1B and the top view shown in the above FIG. 3B, but the present invention is also effective when the elastic middle layer 4 is used for at least a part thereof.

Furthermore, as shown in Fig. 1A, Fig. 2A, and Fig. 3A, a holding portion 41 for holding the image display panel A may be provided on the lower side of the elastic middle layer 4. The elastic middle layer 4 and the holding portion 41 may also be formed as one piece. The width of the holding portion 41, which does not contact the bottom of the elastic middle layer 4, is preferably 5 mm or less, and preferably 3 mm or less, from the viewpoint of narrow frame and light weight. On the other hand, from the viewpoint of holding the image display panel A, the width of the holding portion 41 (the width of the bottom of the elastic middle layer 4) is preferably 0.1 mm or more, and more preferably 0.3 mm or more. FIG2 is an example of a situation in which a gap S is provided between the end surface of the image display panel A and the elastic middle layer 4 in the retaining portion 41 of the elastic middle layer 4, and the edge of the image display panel A is retained by the retaining portion 41. When the gap S is provided, it is preferable to design the width of the retaining portion 41 not in contact with the bottom of the elastic middle layer 4 to be longer than the width of the gap S.

As shown in Fig. 1B, Fig. 2B, and Fig. 3B, the elastic middle layer 4, the outer frame 5, and the inner frame 6 can be arranged in a frame shape. Moreover, when the elastic middle layer 4 is used in a frame shape as shown in Fig. 4 (Fig. 4 is a top view, so the case where the elastic middle layer 4 and the retaining portion 41 are simultaneously recorded), a part of the sides can be omitted from the perspective of handling, etc. Moreover, the inner side of the elastic middle layer 4 can also have a protrusion 42 for embedding in order to fix it to the frame. For example, in Fig. 4, two protrusions 42 are arranged on each of the three sides of the inner side of the frame. The number of the protrusions 42 can be set arbitrarily.

<Outer border, inner border>

The external frame is formed on the outer side of the end surface of the image display panel for protection, and can usually be used without special restrictions for image display panels. The internal frame is formed on the outer side of the end surface of the aforementioned image display panel to protect the outermost surface, and can usually be used without special restrictions for image display panels.

<Elastic middle layer>

As mentioned above, the elastic middle layer is used to prevent the image display panel from directly contacting the image display device body. There is no particular limitation as long as the material can mitigate the impact caused by the aforementioned contact when the laptop is closed. The material forming the elastic middle layer can be a rubber material such as nitrile rubber, fluoro rubber, urethane rubber, silicone rubber, ethylene propylene rubber, hydrogenated nitrile rubber, chloroprene rubber, acrylic rubber, butyl rubber, chlorosulfonated polyethylene, epichlorohydrin rubber, natural rubber, etc., which are used for rubber pads. In addition, the material of the elastic middle layer can also include elastic plastics such as vinyl chloride resin, urethane resin, and cushioning foam.

<Optical film>

The optical film of the present invention is described below. As mentioned above, the optical film of the present invention is a film containing a polarizing film. The optical film of the present invention can be formed by a polarizing film alone, or can be formed by a laminated optical film composed of a polarizing film and other films. The thickness of the aforementioned optical film (the same applies to laminated optical films) is designed so that the aforementioned distance t in the image display panel with a border frame of the present invention satisfies 75 μm or more.

《Polarizing Film》

The polarizing film contained in the aforementioned optical film generally uses a polarizing element having a transparent protective film on one or both sides. The aforementioned polarizing film can be suitably a single-sided protected polarizing film having a transparent protective film on only one side of the polarizing element. In the single-sided protected polarizing film, the aforementioned adhesive layer is preferably provided on the side of the aforementioned single-sided protected polarizing film that does not have the aforementioned transparent protective film.

There is no particular limitation on the aforementioned polarizer, and various polarizers can be used. As polarizers, hydrophilic polymer films such as polyvinyl alcohol films, partially formalized polyvinyl alcohol films, and partially saponified films of ethylene-vinyl acetate copolymers adsorb dichroic substances such as iodine or dichroic dyes and are uniaxially stretched, as well as polyene oriented films such as dehydrated polyvinyl alcohol or dehydrogenated polyvinyl chloride. Among these, polarizers composed of polyvinyl alcohol films and dichroic substances such as iodine are more suitable. There is no particular limitation on the thickness of these polarizers, which is generally less than about 30 μm .

Furthermore, it is preferred that the polarizer be a thin polarizer with a thickness of 3 to 30 μm . It is particularly preferred that a thin polarizer be used for the aforementioned single-sided protective polarizing film. From the perspective of being able to suppress peeling of the adhesive layer even in a humidified environment where there is a risk of contact between the grease or emulsion components and the aforementioned elastic intermediate layer, the thickness of the polarizer is preferably above 3 μm . From the perspective of suppressing dimensional shrinkage in a humidified environment, the thickness of the polarizer is preferably less than 10 μm . A thin polarizer with a thickness of 3 to 10 μm has less thickness variation, better visibility, and less dimensional change, so it has excellent durability. In addition, the thickness of the polarizing film can also be reduced, so it is more ideal from these perspectives.

As the material constituting the transparent protective film, a thermoplastic resin having excellent transparency, mechanical strength, thermal stability, moisture resistance, isotropy, etc. can be used. Specific examples of the thermoplastic resin include cellulose resins such as cellulose triacetate, polyester resins, polyether resins, polyester resins, polycarbonate resins, polyamide resins, polyimide resins, polyolefin resins, (meth)acrylic resins, cyclic polyolefin resins (norbornene resins), polyarylate resins, polystyrene resins, polyvinyl alcohol resins, and mixtures thereof. In addition, on one side of the polarizer, the transparent protective film is bonded by an adhesive layer, and on the other side, the transparent protective film can use a thermosetting resin or UV-curing resin such as (meth) acrylic, urethane, acrylic urethane, epoxy, or silicone.

The material of the transparent protective film is preferably a cellulose resin or a (meth) acrylic resin. The (meth) acrylic resin is preferably a (meth) acrylic resin having a lactone ring structure. Examples of the (meth) acrylic resin having a lactone ring structure include the (meth) acrylic resin having a lactone ring structure described in Japanese Patent Publication No. 2000-230016, Japanese Patent Publication No. 2001-151814, Japanese Patent Publication No. 2002-120326, Japanese Patent Publication No. 2002-254544, Japanese Patent Publication No. 2005-146084, etc. In particular, cellulose resin is more effective than (meth) acrylic resin in suppressing cracks in polarizers, which is a problem in single-sided protective films having a transparent protective film on only one side of the polarizer, and is therefore preferred from this point of view. The thickness of the aforementioned transparent protective film is generally preferably 10 to 100 μm , preferably 20 to 50 μm , and more preferably 30 to 50 μm . In particular, when using cellulose resin as the material for the transparent protective film, controlling the thickness to less than 100 μm can suppress dimensional shrinkage in a humidified environment, and is therefore preferred.

As long as the adhesive used for bonding the polarizer and the transparent protective film is optically transparent, various forms of adhesives such as water-based, solvent-based, hot melt adhesive-based, free radical curing, and cationic curing can be used without particular restrictions, but water-based adhesives or free radical curing adhesives are more suitable.

≪Surface treatment layer≫

A surface treatment layer may also be provided on the outermost surface of the aforementioned optical film. The surface treatment layer may be a functional layer such as a hard coating layer, an anti-reflection layer, an anti-adhesion layer, a diffusion layer or an anti-glare layer. The surface treatment layer may be provided on a transparent protective film used for the polarizing film, or may be provided on another substrate different from the aforementioned transparent protective film. The other substrate may be the same as the aforementioned transparent protective film. When the surface treatment layer is provided, an adhesive layer known in the past may be used to adhere to the aforementioned polarizing film. The aforementioned surface treatment layer is provided on the side opposite to the side on which the aforementioned adhesive layer is provided in the aforementioned polarizing film of the aforementioned optical film.

The material used to form the hard coating layer provided as the surface treatment layer may be, for example, a thermoplastic resin or a material that can be cured by heat or radiation. Examples of the material include heat-curing resins, ultraviolet-curing resins, electron-ray-curing resins, and other radiation-curing resins. Among these, ultraviolet-curing resins are preferred, and the ultraviolet-curing resins can be cured by ultraviolet irradiation to efficiently form a cured resin layer with a simple processing operation. Examples of these curing resins include various resins such as polyesters, acrylics, urethanes, amides, silicones, epoxys, and melamines, and include monomers, oligomers, and polymers thereof. From the perspective of rapid processing speed and less heat damage to the substrate, radiation-curing resins, especially UV-curing resins, are preferred. Suitable UV-curing resins include, for example, those having UV-polymerizable functional groups, including acrylic monomers or oligomers having two or more such functional groups, especially 3 to 6 such functional groups. In addition, the UV-curing resin is mixed with a photopolymerization initiator.

In addition, as for the aforementioned surface treatment layer, an anti-glare treatment layer or an anti-reflection layer can be provided for the purpose of improving visibility. And an anti-glare treatment layer or an anti-reflection layer can be provided on the aforementioned hard coating layer. The constituent material of the anti-glare treatment layer is not particularly limited, for example, radiation-hardening resins, thermosetting resins, thermoplastic resins, etc. can be used. The anti-reflection layer can use titanium oxide, zirconium oxide, silicon oxide, magnesium fluoride, etc. The anti-reflection layer can be provided in multiple layers. In addition, the surface treatment layer can also provide an anti-adhesive layer, etc.

≪Other layers≫

In addition to the aforementioned layers, the aforementioned optical film (laminated optical film) may also be laminated with a phase difference film (including 1/2 or 1/4 equal wavelength plates), a visual compensation film, etc. In addition, an anchoring layer, an easy-to-bond layer, or various easy-to-bond treatments such as corona treatment and plasma treatment may be provided on the aforementioned polarizing film or other optical layers.

As phase difference films, there can be mentioned birefringent films made by uniaxial or biaxial stretching of polymer materials, oriented films of liquid crystal polymers, and oriented layers of liquid crystal polymers supported by films. Such phase difference films can be single layers or combined or have more than two layers.

When an optical film with an adhesive layer is applied to an image display panel for a PC, the phase difference film is preferably placed between the polarizer and the image display portion from the perspective of viewing angle compensation and low reflectivity, and is differentiated from the above-mentioned transparent protective film. In addition, the phase difference film can generally be used with a thickness of 4 to 150 μm , but from the perspective of suppressing the peeling of the adhesive layer in a humidified environment or the cracking of the phase difference film, it is more advantageous to be thinner within an appropriate range, for example, the thickness (total) of the phase difference film is 2 to 25 μm , and 4 to 24 μm is more preferred.

(Definition of terms and symbols)

The definitions of terms and symbols in this manual are as follows.

(1) Refractive index (nx, ny, nz)

"nx" is the refractive index in the direction where the refractive index is the largest in the plane (i.e. the slow axis direction), "ny" is the refractive index in the direction orthogonal to the slow axis in the plane (i.e. the fast axis direction), and "nz" is the refractive index in the thickness direction.

(2) In-plane phase difference (Re)

"Re(λ)" is the in-plane phase difference of the film measured at 23°C with light of wavelength λnm. For example, "Re(450)" is the in-plane phase difference of the film measured at 23°C with light of wavelength 450nm. Re(λ) can be obtained by the formula: Re=(nx-ny)×d when the thickness of the film is d(nm).

(3) Phase difference in thickness direction (Rth)

"Rth(λ)" is the phase difference of the film in the thickness direction measured at 23°C with light of 550nm wavelength. For example, "Rth(450)" is the phase difference of the film in the thickness direction measured at 23°C with light of 450nm wavelength. Rth(λ) can be obtained by the formula: Rth=(nx-nz)×d when the film thickness is d(nm).

<Adhesive layer>

The adhesive layer used to bond the optical film to the image display portion is described below. The adhesive layer is formed by the following adhesive composition, which contains a (meth)acrylic polymer (A) as a base polymer, and the (meth)acrylic polymer (A) contains 80% by mass or more of a monomer (a) as a monofunctional monomer unit, and the monomer (a) is selected from at least one of a (meth)acrylic acid alkyl ester having an alkyl group with 1 to 4 carbon atoms, a (meth)acrylic acid alkoxyalkyl ester, a fluorine-containing monomer, and acrylonitrile, and contains 20% by mass or more of n-butyl acrylate, or 70% by mass or more of a (meth)acrylic acid alkoxyalkyl ester. The monofunctional monomer unit is a unit of a compound that constitutes the (meth)acrylic polymer (A) and has one unsaturated double bond such as a (meth)acrylic group or a vinyl group. The aforementioned (meth)acrylic polymer (A) includes a partial polymer of a monomer component containing the aforementioned (meth)acrylic acid alkyl ester (a) and/or a (meth)acrylic polymer obtained from the aforementioned monomer component. In addition, (meth)acrylic ester refers to acrylate and/or methacrylate, and (meth) in the present invention is also synonymous.

The main skeleton of the aforementioned (meth)acrylic polymer (A) is formed by a monomer (a), and the monomer (a) is selected from at least one of the aforementioned (meth)acrylic acid alkyl esters having an alkyl group with 1 to 4 carbon atoms, (meth)acrylic acid alkoxyalkyl esters, fluorinated monomers, and acrylonitrile. As the aforementioned monomer unit, the mass ratio of the aforementioned monomer (a) in the mass ratio of the total constituent monomers (monofunctional monomers 100 mass%, the same below) constituting the (meth)acrylic polymer (A) is 80 mass% or more. By using the (meth)acrylic polymer (A) of the aforementioned ratio, the aforementioned adhesive layer can be suppressed from peeling off even in a humidified environment where there is a risk of contact between oil or emulsifiable components and the aforementioned elastic intermediate layer.

The alkyl group in the aforementioned (meth)acrylic acid alkyl ester having an alkyl group with 1 to 4 carbon atoms may be a linear or branched alkyl group, such as a methyl group, an ethyl group, a propyl group, an isopropyl group, a n-butyl group, an isobutyl group, a tertiary butyl group, etc.

The aforementioned alkyl (meth)acrylate having an alkyl group with 1 to 4 carbon atoms is preferably an alkyl (meth)acrylate having an alkyl group with 4 carbon atoms, and is particularly preferably n-butyl acrylate. n-butyl acrylate is an essential monomer unit constituting the (meth)acrylic polymer (A), and the aforementioned monomer (a) may be constituted by n-butyl acrylate alone. As a monomer unit, the mass ratio of n-butyl acrylate in the mass ratio of the total monomers constituting the (meth)acrylic polymer (A) (monofunctional monomer 100 mass %) is 20 mass % or more. By using the (meth)acrylic polymer (A) having the above ratio, the aforementioned adhesive layer can be suppressed from peeling off even in a humidified environment where there is a risk of contact between oil or emulsifiable concentrate components and the aforementioned elastic intermediate layer. The mass ratio of n-butyl acrylate can be 30% or more, 40% or more, 50% or more, 60% or more, 70% or more, 80% or more, and preferably 90% or more.

The above-mentioned alkoxyalkyl (meth)acrylate is not particularly limited, and the above-mentioned alkoxyalkyl is preferably an alkoxyalkyl with a total carbon number of 3 to 25. For example, the above-mentioned alkoxyalkyl (meth)acrylate can include 2-methoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, 3-methoxypropyl (meth)acrylate, 3-ethoxypropyl (meth)acrylate, 4-methoxybutyl (meth)acrylate, ethoxybutyl (meth)acrylate, etc. Other examples include alkoxypolyalkylene glycols such as methoxytriethylene glycol (meth)acrylate, and commercially available products include methoxypolyethylene glycol (meth)acrylate (bisma MPE400A manufactured by Osaka Organic Chemical Industries, Ltd.).

The fluorine-containing monomer is not particularly limited, and examples thereof include a monomer having a free radical polymerizable carbon-carbon double bond such as a (meth)acryl group or a vinyl group and having at least one fluorine-substituted alkyl group having 3 to 10 carbon atoms. For example, the fluoromonomer may include 2,2,2-trifluoroethyl acrylate, 2-(perfluorohexyl)ethyl acrylate, 2,2,3,3,3-pentafluoropropyl acrylate, 2-(perfluorobutyl)ethyl acrylate, 3-perfluorobutyl-2-hydroxypropyl acrylate, 3-perfluorohexyl-2-hydroxypropyl acrylate, 3-(perfluoro-3-methylbutyl)-2-hydroxypropyl acrylate, 1H,1H,3H-tetrafluoropropyl acrylate, 1H,1H,5H-octafluoropentyl acrylate, 1H,1H,7H-dodecyl acrylate, 1H-1-(trifluoromethyl)trifluoroethyl acrylate, 1H,1H,3H-hexafluorobutyl acrylate, 1,2,2,2-tetrafluoro-1-(trifluoromethyl)ethyl acrylate, and the like. In addition, among the above-mentioned fluorine-containing monomers, those having a hydroxyl group are not included in the hydroxyl-containing monomers described below.

Furthermore, the monomer (a) is at least one selected from (meth) acrylate alkyl esters having an alkyl group with 1 to 4 carbon atoms, (meth) acrylate alkoxyalkyl esters, fluorinated monomers, and acrylonitrile, but the monomer (a) may be entirely composed of the (meth) acrylate alkyl esters having an alkyl group with 1 to 4 carbon atoms (aspect (1)). In the aspect (1), it is preferred that the monomer unit contains 30% by mass or more of n-butyl acrylate. The aspect (1) is preferred from the viewpoint of heating and ensuring wet-heat durability.

For example, in the embodiment (1) in which the monomer (a) is entirely composed of the aforementioned (meth) alkyl esters having an alkyl group with 1 to 4 carbon atoms, the embodiment (10) in which the aforementioned monomer (a) is entirely composed of n-butyl acrylate can be adopted. In the embodiment (10), the aforementioned monomer unit preferably contains 70% by mass or more of n-butyl acrylate. At this time, the aforementioned monomer unit of n-butyl acrylate may vary depending on the type of copolymer monomer, crosslinking agent, etc., but it can be used at 80% by mass or more, 90% by mass or more, and even 95% by mass or more. The embodiment (10) is preferred from the viewpoint of heating and ensuring wet heat durability.

In the embodiment (1) in which all the monomers (a) are the aforementioned (meth)acrylic acid alkyl esters having an alkyl group with 1 to 4 carbon atoms, for example, the embodiment (11) can be adopted in which, in addition to n-butyl acrylate, the aforementioned (meth)acrylic acid alkyl esters having an alkyl group with 1 to 4 carbon atoms are used in combination. The aforementioned (meth)acrylic acid alkyl esters having an alkyl group with 1 to 4 carbon atoms in addition to n-butyl acrylate are preferably (meth)acrylic acid alkyl esters having an alkyl group with 1 to 3 carbon atoms and tertiary butyl acrylate. The (meth)acrylic acid alkyl esters having an alkyl group with 1 to 3 carbon atoms are preferably (meth)acrylic acid alkyl esters having an alkyl group with 1 to 2 carbon atoms such as methyl acrylate, methyl methacrylate, and ethyl acrylate. That is, in the embodiment (11) in which n-butyl acrylate and the aforementioned monomers (a) in addition to n-butyl acrylate are used in combination, the aforementioned monomers (a) are preferably (meth)acrylic acid alkyl esters having an alkyl group with 1 to 3 carbon atoms or tertiary butyl acrylate, and n-butyl acrylate. This aspect (11) is better from the perspectives of oil resistance, processability, handling, and crack resistance.

In the case of the aforementioned combined system (11), the aforementioned mass ratio of the aforementioned alkyl (meth)acrylate having an alkyl group with 1 to 3 carbon atoms is preferably set to 4 to 60 mass %, preferably 4 to 50 mass %, and more preferably 10 to 40 mass %; on the other hand, the aforementioned mass ratio of n-butyl acrylate is preferably set to 30 mass % or more, preferably 30 to 96 mass %, more preferably 40 to 90 mass %, and preferably adjusted to a total of 80 mass % or more.

Furthermore, in the embodiment (11) of the combined system, when the alkyl acrylate is used as the alkyl (meth)acrylate having an alkyl group of 1 to 4 carbon atoms (except for n-butyl acrylate), the mass ratio of the alkyl acrylate is preferably set to 15 to 60 mass%, preferably 15 to 45 mass%, and more preferably 20 to 40 mass%. On the other hand, the mass ratio of n-butyl acrylate is preferably set to 30 mass% or more, preferably 40 to 85 mass%, more preferably 40 to 75 mass%, and preferably adjusted to a total of 80 mass% or more. This embodiment (11A) is preferred from the viewpoints of oil resistance, processability, handling, and crack resistance.

Furthermore, in the embodiment (11) of the combined system, when the aforementioned (meth)acrylic acid alkyl ester (except for n-butyl acrylate) is used as methacrylic acid alkyl ester (11B), the aforementioned mass ratio of the aforementioned methacrylic acid alkyl ester is preferably set to 5-15 mass%, and preferably to 5-10 mass%; on the other hand, the aforementioned mass ratio of n-butyl acrylate is preferably set to 70 mass% or more, and preferably to 70-90 mass%, and preferably adjusted to a total of 80 mass% or more. This embodiment (11B) is preferred from the viewpoint of processability or handling, and crack resistance.

Furthermore, the monomer (a) may be, for example, a state (21) in which the aforementioned (meth)acrylic acid alkyl ester having an alkyl group with 1 to 4 carbon atoms and the aforementioned fluorine-containing monomer are used in combination. In the state (21) of the aforementioned combined system, the aforementioned mass ratio of the aforementioned (meth)acrylic acid alkyl ester having an alkyl group with 1 to 4 carbon atoms is preferably set to 30 mass% or more, and preferably set to 30 to 55 mass%, and the fluorine-containing monomer is preferably set to 25 mass% or more, and preferably set to 25 to 50 mass%, and preferably adjusted to a total of 80 mass% or more, and n-butyl acrylate is preferably adjusted to 30 mass% or more, and more preferably adjusted to 30 to 55 mass%. This state (21) is preferred from the perspective of oil resistance.

Furthermore, the monomer (a) may be used in the form (22) of the aforementioned (meth) acrylic acid alkyl ester having an alkyl group with 1 to 4 carbon atoms and acrylonitrile in combination. In the form (22) of the aforementioned combined system, the aforementioned mass ratio of the aforementioned (meth) acrylic acid alkyl ester having an alkyl group with 1 to 4 carbon atoms is preferably set to 70 mass% or more, and preferably set to 70 to 85 mass%, and acrylonitrile is preferably set to 5 mass% or more, and preferably set to 10 to 20 mass%, and preferably adjusted to a total of 80 mass% or more, and n-butyl acrylate is preferably adjusted to 70 mass% or more, and preferably adjusted to 70 to 85 mass%. This form (22) is preferred from the perspective of heat durability.

Furthermore, the monomer (a) may adopt, for example, the embodiment (23) using 70% by mass or more of the aforementioned (meth) alkoxyalkyl ester. In the aforementioned embodiment (23), 80% by mass or more, 90% by mass or more, and 100% by mass of the aforementioned (meth) alkoxyalkyl ester may be used. Furthermore, the aforementioned (meth) alkyl ester having an alkyl group with 1 to 4 carbon atoms may be used in combination in embodiment (23). The aforementioned mass ratio of the aforementioned (meth) alkyl ester having an alkyl group with 1 to 4 carbon atoms is preferably set to 20% by mass or more, the aforementioned (meth) alkoxyalkyl ester is preferably set to 70% by mass or more, and is preferably set to 70 to 99% by mass, and is preferably adjusted to a total of 80% by mass or more, and n-butyl acrylate is preferably adjusted to 20% by mass or more. This embodiment (23) is preferred from the viewpoint of high adhesion and oil resistance.

In addition, in the above-mentioned combined system aspects (21) to (23), within the range where n-butyl acrylate or the aforementioned alkoxyalkyl (meth)acrylate satisfies the aforementioned mass ratio, the aforementioned (meth)acrylate alkyl ester having an alkyl group with 1 to 4 carbon atoms may be used in combination with a monomer other than n-butyl acrylate. In particular, in the above-mentioned aspect (21), the aforementioned (meth)acrylate alkyl ester having an alkyl group with 1 to 4 carbon atoms may be used in addition to n-butyl acrylate, in addition to the aforementioned alkyl acrylate alkyl ester having an alkyl group with 1 to 3 carbon atoms.

Furthermore, in order to improve adhesion and heat resistance, in addition to the monomer units of the aforementioned monomer (a), one or more copolymerizable monomers having unsaturated double bonds such as (meth)acrylic acid or vinyl groups may be introduced into the (meth)acrylic polymer (A) by copolymerization. The mass ratio of the aforementioned copolymerizable monomer is 20 mass % or less.

However, a higher polymerization ratio of the alkyl (meth)acrylate having an alkyl group with more than 5 carbon atoms is not good from the viewpoint of suppressing the peeling of the aforementioned adhesive. Therefore, the polymerization ratio of the alkyl (meth)acrylate having an alkyl group with more than 5 carbon atoms is 20% by mass or less, preferably 15% by mass or less, and preferably 10% by mass or less, preferably 5% by mass or less, more preferably 3% by mass or less, and even more preferably 1% by mass or less, and it is best not to use it.

The aforementioned copolymer monomer may be, for example, an aromatic ring-containing (meth)acrylate. An aromatic ring-containing (meth)acrylate is a compound containing an aromatic ring structure and a (meth)acryloyl group in its structure. Examples of the aromatic ring include a benzene ring, a naphthalene ring, or a biphenyl ring.

Specific examples of aromatic ring-containing (meth)acrylates include benzyl (meth)acrylate, phenyl (meth)acrylate, o-phenylphenol (meth)acrylate, phenoxy (meth)acrylate, phenoxyethyl (meth)acrylate, phenoxypropyl (meth)acrylate, phenoxydiethylene glycol (meth)acrylate, ethylene oxide-modified nonylphenol (meth)acrylate, ethylene oxide-modified cresol (meth)acrylate, phenol ethylene oxide-modified (meth)acrylate, 2-hydroxy- 3-phenoxypropyl (meth)acrylate, methoxybenzyl (meth)acrylate, chlorobenzyl (meth)acrylate, cresol (meth)acrylate, polystyrene (meth)acrylate and the like having a benzene ring; hydroxyethylated β-naphthol acrylate, 2-naphthol ethyl (meth)acrylate, 2-naphthyloxyethyl acrylate, 2-(4-methoxy-1-naphthyloxy)ethyl (meth)acrylate and the like having a naphthyl ring; biphenyl (meth)acrylate and the like having a biphenyl ring.

From the viewpoint of adhesion and durability, the aforementioned aromatic ring-containing (meth)acrylate is preferably benzyl (meth)acrylate, phenoxyethyl (meth)acrylate, and especially phenoxyethyl (meth)acrylate.

The aforementioned mass ratio of the aromatic ring-containing (meth)acrylate is less than 20 mass %, preferably 3 to 18 mass %, preferably 5 to 16 mass %, and more preferably 10 to 14 mass %. When the mass ratio of the aromatic ring-containing (meth)acrylate is 3 mass % or more, it is better from the perspective of suppressing display unevenness.

Furthermore, the aforementioned copolymer monomers may include functional group-containing monomers such as hydroxyl group-containing monomers, carboxyl group-containing monomers, and amide group-containing monomers.

A hydroxyl-containing monomer is a compound containing a hydroxyl group in its structure and a polymerizable unsaturated double bond such as a (meth)acryloyl group or a vinyl group. Specific examples of hydroxyl-containing monomers include 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, 12-hydroxylauryl (meth)acrylate, and other hydroxyalkyl (meth)acrylates or (4-hydroxymethylcyclohexyl)-methacrylate. From the perspective of durability, the aforementioned hydroxyl-containing monomers are preferably 2-hydroxyethyl (meth)acrylate and 4-hydroxybutyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate is particularly preferred.

A carboxyl group-containing monomer is a compound containing a carboxyl group and a polymerizable unsaturated double bond such as a (meth)acrylic acid group or a vinyl group in its structure. Specific examples of carboxyl group-containing monomers include (meth)acrylic acid, carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid, etc. Among the above carboxyl group-containing monomers, acrylic acid is preferred from the viewpoints of copolymerizability, price, and adhesive properties.

When the adhesive composition contains a crosslinking agent, hydroxyl-containing monomers and carboxyl-containing monomers will become reaction points with the crosslinking agent. Since hydroxyl-containing monomers and carboxyl-containing monomers have good intermolecular reactivity with the crosslinking agent, it is advisable to use these monomers in order to enhance the cohesion and heat resistance of the obtained adhesive layer.

The mass ratio of the hydroxyl-containing monomer is preferably less than 3 mass%, preferably 0.01 to 3 mass%, more preferably 0.1 to 2 mass%, and more preferably 0.2 to 2 mass%. From the perspective of the crosslinking adhesive layer, durability or adhesive properties, the mass ratio of the hydroxyl-containing monomer is preferably set to 0.01 mass% or more. On the other hand, when it is greater than 3 mass%, it is not good from the perspective of durability.

The mass ratio of the carboxyl group-containing monomer is preferably less than 10 mass %, and preferably 0.01 to 8 mass %, more preferably 0.05 to 6 mass %, and even more preferably 0.1 to 5 mass %. It is better to set the mass ratio of the carboxyl group-containing monomer to 0.01 mass % or more from the perspective of durability.

An amide group-containing monomer is a compound containing an amide group in its structure and containing a polymerizable unsaturated double bond such as a (meth)acrylamide group or a vinyl group. Specific examples of amide group-containing monomers include (meth)acrylamide, N,N-dimethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, N-isopropylacrylamide, N-methyl(meth)acrylamide, N-butyl(meth)acrylamide, N-hexyl(meth)acrylamide, N-hydroxymethyl(meth)acrylamide, N-hydroxymethyl-N-propane(meth)acrylamide, aminomethyl(meth)acrylamide, Acrylamide monomers such as (methyl)acrylamide, aminoethyl (meth)acrylamide, methyl (meth)acrylamide, ethyl (meth)acrylamide; N-(meth)acrylaminophenoxol, N-(meth)acrylpiperidine, N-(meth)acrylpyrrolidine and other N-acryl heterocyclic monomers; N-vinylpyrrolidone, N-vinyl-ε-caprolactam and other N-vinyl lactam monomers. Amide-containing monomers are preferred in terms of suppressing the increase in surface resistance over time (especially in a humidified environment) or satisfying durability. In particular, among the amide-containing monomers, N-vinyl lactam monomers are particularly preferred.

A large mass ratio of the amide-containing monomer tends to reduce the anchoring property of the optical film, so the mass ratio should be less than 10 mass%, and preferably less than 5 mass%. From the perspective of suppressing the increase in surface resistance over time (especially in a humidified environment), it should be more than 0.1 mass%. The mass ratio should be more than 0.3 mass%, and more preferably more than 0.5 mass%.

Specific examples of other copolymer monomers other than the above include monomers containing anhydride groups such as maleic anhydride and itaconic anhydride; caprolactone adducts of acrylic acid; monomers containing sulfonic acid groups such as allyl sulfonic acid, 2-(meth)acrylamido-2-methylpropanesulfonic acid, (meth)acrylamidopropanesulfonic acid, and sulfopropyl (meth)acrylate; and monomers containing phosphate groups such as 2-hydroxyethylacryloyl phosphate.

Examples of monomers for the purpose of modification include alkylaminoalkyl (meth)acrylates such as aminoethyl (meth)acrylate, N,N-dimethylaminoethyl (meth)acrylate, and tertiary butylaminoethyl (meth)acrylate; alkoxyalkyl (meth)acrylates such as methoxyethyl (meth)acrylate and ethoxyethyl (meth)acrylate; N-(meth)acryloyloxymethylenesuccinimide or N-(meth)acryloyl-6-oxyhexamethylenesuccinimide, N-(meth)acryloyloxymethylenesuccinimide; ) Succinimide monomers such as acrylyl-8-oxyoctamethylene succinimide; maleimide monomers such as N-cyclohexylmaleimide or N-isopropylmaleimide, N-laurylmaleimide or N-phenylmaleimide; iconimide monomers such as N-methyliconimide, N-ethyliconimide, N-butyliconimide, N-octyliconimide, N-2-ethylhexyliconimide, N-cyclohexyliconimide, N-lauryliconimide, etc.

Furthermore, the modified monomers may also include vinyl monomers such as vinyl acetate and vinyl propionate; epoxy (meth)acrylates such as glycidyl (meth)acrylate; glycol (meth)acrylates such as polyethylene glycol (meth)acrylate and polypropylene glycol (meth)acrylate; (meth)acrylate monomers such as tetrahydrofurfuryl (meth)acrylate and polysiloxane (meth)acrylate, etc. Isoprene, butadiene, isobutylene, vinyl ether, etc. may also be used.

In addition, copolymerizable monomers other than the above-mentioned monomers include silane monomers containing silicon atoms. Examples of silane monomers include 3-acryloxypropyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 4-vinylbutyltrimethoxysilane, 4-vinylbutyltriethoxysilane, 8-vinyloctyltrimethoxysilane, 8-vinyloctyltriethoxysilane, 10-methacryloxydecyltrimethoxysilane, 10-acryloxydecyltrimethoxysilane, 10-methacryloxydecyltriethoxysilane, 10-acryloxydecyltriethoxysilane, etc.

In the mass ratio of the total constituent monomers (monofunctional monomers 100 mass %) of the aforementioned (meth)acrylic polymer (A), the ratio of the aforementioned other copolymerized monomers in the (meth)acrylic polymer (A) is preferably about 0 to 10 mass %, preferably about 0 to 7 mass %, and more preferably about 0 to 5 mass %.

In addition, as the copolymer monomer, tripropylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, bisphenol A diglycidyl ether di(meth)acrylate, neopentyl glycol di(meth)acrylate, trihydroxymethylenepropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate can also be used. Ester, caprolactone-modified dipentatriol hexa(meth)acrylate and polyol esters such as (meth)acrylate and polyols having two or more (meth)acrylic acid groups, vinyl groups and other unsaturated double bonds, or polyester (meth)acrylate, epoxy (meth)acrylate, urethane (meth)acrylate, etc., with two or more (meth)acrylic acid groups, vinyl groups and other unsaturated double bonds added to the skeleton of polyester, epoxy, urethane, etc. as the same functional group as the monomer component.

For the aforementioned copolymer monomers, when the aforementioned multifunctional monomers are used, the multifunctional monomers will function as crosslinking components. The amount of the aforementioned multifunctional monomers used will vary depending on their molecular weight or functional groups, but relative to a total of 100 parts by mass of the monofunctional monomers, it is preferably used in an amount of less than 1 part by mass, and preferably less than 0.5 parts by mass. The lower limit value is not particularly limited, but preferably more than 0 parts by mass, and more preferably more than 0.01 parts by mass. By using the amount of the multifunctional monomers within the aforementioned range, the bonding strength can be improved.

The (meth)acrylic polymer (A) of the present invention generally preferably has a weight average molecular weight of 1 million to 2.5 million. In view of durability, especially heat resistance, the weight average molecular weight is preferably 1.2 million to 2 million. From the viewpoint of heat resistance, the weight average molecular weight is preferably 1 million or more. If the weight average molecular weight is greater than 2.5 million, the adhesive tends to harden and peeling occurs easily. In addition, the weight average molecular weight (Mw)/number average molecular weight (Mn) showing the molecular weight distribution is preferably 1.8 or more and 10 or less, preferably 1.8 to 7, and more preferably 1.8 to 5. If the molecular weight distribution (Mw/Mn) is greater than 10, it is not suitable from the viewpoint of durability. In addition, the weight average molecular weight and molecular weight distribution (Mw/Mn) are measured by GPC (gel permeation chromatography) and calculated using polystyrene conversion.

The (meth)acrylic polymer (A) can be produced by appropriately selecting various known production methods such as solution polymerization, block polymerization, emulsion polymerization, radiation (UV) polymerization, and other free radical polymerization methods. In addition, the obtained (meth)acrylic polymer (A) can be any of a random copolymer, a block copolymer, a graft copolymer, and the like.

In addition, in solution polymerization, the polymerization solvent may be ethyl acetate, toluene, etc. As a specific example of solution polymerization, the reaction may be carried out under a flow of an inert gas such as nitrogen, with the addition of a polymerization initiator, and is generally carried out under reaction conditions of about 50-70°C and about 5-30 hours.

The polymerization initiator, chain transfer agent, emulsifier, etc. used in the free radical polymerization can be appropriately selected and used without particular limitation. In addition, the weight average molecular weight of the (meth)acrylic polymer (A) can be controlled by the amount of the polymerization initiator and chain transfer agent used and the reaction conditions, and the amount used can be appropriately adjusted according to the type of the initiator and chain transfer agent.

Furthermore, the adhesive composition used to form the adhesive layer of the present invention contains a silane coupling agent (B) as an additive. By combining the aforementioned silane coupling agent (B) with a (meth) acrylic polymer (A) containing 80% by mass or more of the aforementioned (meth) acrylic acid alkyl ester (a) having a carbon number of 1 to 4 as a monomer unit, the peeling of the adhesive layer can be suppressed even in a humidified environment where there is a risk of contact between the oil or emulsifiable concentrate component and the aforementioned elastic intermediate layer.

The aforementioned silane coupling agent (B) is preferably at least one selected from epoxy-containing silane coupling agents (b1) and butyl-containing silane coupling agents (b2).

Examples of the epoxy-containing silane coupling agent (b1) include low molecular weight (non-oligomer type) epoxy-containing silane coupling agents such as 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, and 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, or oligomer type epoxy-containing silane coupling agents such as X-41-1053, X-41-1056, X-41-1059A, X-24-9590, and KR-516 manufactured by Shin-Etsu Chemical Co., Ltd. In view of the great effect of inhibiting the peeling of the adhesive layer in a humidified environment where there is a risk of contact between the oil or emulsion components and the elastic intermediate layer, the aforementioned epoxy-containing silane coupling agent (b1) is preferably a low molecular weight (non-oligomer type) epoxy-containing silane coupling agent.

In addition, the aforementioned silane coupling agent containing a silane group (b2) may include low molecular weight (non-oligomer type) silane coupling agents containing a silane group such as 3-butyltrimethoxysilane, 3-butylmethyldimethoxysilane, 3-butyltriethoxysilane, 3-butylmethyldiethoxysilane, β-butylmethylphenylethyltrimethoxysilane, butylmethyltrimethoxysilane, 6-butylhexyltrimethoxysilane, 10-butyldecyltrimethoxysilane, or X-41-1805, X-41-1810, X-41-1818 manufactured by Shin-Etsu Chemical Co., Ltd. In view of the great effect of inhibiting the peeling of the adhesive layer in a humidified environment where there is a risk of contact between the oil or emulsion components and the elastic intermediate layer, the aforementioned silane coupling agent containing a silane group (b2) is preferably an oligomer type silane coupling agent containing a silane group.

In addition, the low molecular weight silane coupling agent (B) other than the above-mentioned ones may be for example, silane coupling agents containing acetyl groups such as A100 manufactured by Soken Chemical Co., Ltd.; silane coupling agents containing amino groups such as 3-aminopropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, 3-triethoxysilyl-N-(1,3-dimethylbutylene)propylamine, N-phenyl-γ-aminopropyltrimethoxysilane; silane coupling agents containing (meth)acryl groups such as 3-acryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane; silane coupling agents containing isocyanate groups such as 3-isocyanatepropyltriethoxysilane, etc. In addition, oligomer-type silane coupling agents other than those mentioned above can be polymerized, such as KR-213 manufactured by Shin-Etsu Chemical Co., Ltd.

Such silane coupling agents with multiple alkoxysilane groups in the molecule are less volatile and have multiple alkoxysilane groups, so they can effectively improve durability and are more ideal. Especially when the adherend of the optical film with the adhesive is a transparent conductive layer (such as ITO, etc.) that is less likely to react with alkoxysilane groups than glass, the durability is still good. In addition, the so-called oligomer type refers to a polymer whose monomer is a dimer or more and less than about 100 polymers, and the weight average molecular weight of the oligomer type silane coupling agent is preferably about 300~30000.

The silane coupling agent (B) may be used alone or in combination of two or more thereof. The total content of the silane coupling agent (B) is preferably 0.01 to 5 parts by mass, more preferably 0.02 to 3 parts by mass, more preferably 0.05 to 1 part by mass, and most preferably 0.1 to 0.8 parts by mass, based on 100 parts by mass of the (meth)acrylic polymer (A). In addition, as mentioned above, the aforementioned silane coupling agent (B) is preferably at least one selected from epoxy-containing silane coupling agents (b1) and butyl-containing silane coupling agents (b2), and when the silane coupling agents (b1), (b2) and other silane coupling agents are used together, the other silane coupling agents can be used in an amount of 3 parts by mass or less and the same amount as the aforementioned silane coupling agent (B) relative to 100 parts by mass of the aforementioned (meth)acrylic polymer (A).

The adhesive composition of the present invention may contain a crosslinking agent (C). As the crosslinking agent (C), an organic crosslinking agent or a multifunctional metal chelate may be used. Examples of organic crosslinking agents include isocyanate crosslinking agents, peroxide crosslinking agents, epoxy crosslinking agents, and imine crosslinking agents. Multifunctional metal chelates are covalently bonded or coordinately bonded polyvalent metals and organic compounds. Examples of polyvalent metal atoms include Al, Cr, Zr, Co, Cu, Fe, Ni, V, Zn, In, Ca, Mg, Mn, Y, Ce, Sr, Ba, Mo, La, Sn, and Ti. Atoms that can form covalent bonds or coordinate bonds in organic compounds include oxygen atoms, etc., and organic compounds include alkyl esters, alcohol compounds, carboxylic acid compounds, ether compounds, ketone compounds, etc.

The aforementioned crosslinking agent (C) is preferably an isocyanate crosslinking agent. Isocyanate crosslinking agents can use compounds having at least two isocyanate groups. For example, well-known aliphatic polyisocyanates, alicyclic polyisocyanates, aromatic polyisocyanates, etc. used in urethanization reactions are generally used.

The amount of the crosslinking agent (C) used relative to 100 parts by weight of the (meth)acrylic polymer (A) is preferably 3 parts by weight or less, and preferably 0.01 to 3 parts by weight, more preferably 0.02 to 2 parts by weight, and even more preferably 0.03 to 1 part by weight. In addition, when the crosslinking agent (C) is less than 0.01 parts by weight, the adhesive may not be sufficiently crosslinked and may not satisfy the durability or adhesive properties; on the other hand, if it is more than 3 parts by weight, the adhesive may become too hard and tend to have reduced durability.

In addition, the adhesive composition of the present invention may contain other known additives, for example, antistatic agents, colorants, pigments and other powders, dyes, surfactants, plasticizers, thickeners, surface lubricants, levelers, softeners, antioxidants, anti-aging agents, light stabilizers, ultraviolet absorbers, polymerization inhibitors, inorganic or organic fillers, metal powders, granular, foil-like objects, etc. can be appropriately added according to the application. In addition, a redox system with a reducing agent added can also be used within a controllable range. The additives are preferably used in an amount of less than 5 parts by mass, more preferably less than 3 parts by mass, and more preferably less than 1 part by mass relative to 100 parts by mass of the (meth)acrylic polymer (A).

On the other hand, the adhesive composition of the present invention does not contain a polyether compound having a polyether skeleton and a reactive silyl group at at least one end. The aforementioned polyether compound having a reactive silyl group can be exemplified by the one disclosed in Japanese Patent Publication No. 2010-275522. The aforementioned polyether compound having a reactive silyl group is preferred from the viewpoint of improving the workability, but is not good from the viewpoint of inhibiting the peeling of the adhesive layer in a humidified environment where there is a risk of contact between the grease or emulsifiable component and the aforementioned elastic intermediate layer. When the aforementioned polyether compound having a reactive silyl group is used, even if the aforementioned silane coupling agent (B) is used, the peeling of the aforementioned adhesive layer cannot be inhibited.

The adhesive layer of the present invention can be used in the form of an optical film with an adhesive layer attached to an optical film (including at least one polarizing film). The optical film with an adhesive layer can be obtained by forming an adhesive layer on at least one side of the optical film with the aforementioned adhesive composition.

The method for forming the aforementioned adhesive layer can be prepared by, for example, the following method: applying the aforementioned adhesive composition to a separation piece that has been subjected to a peeling treatment, and drying to remove the polymerization solvent, etc. to form an adhesive layer, and then transferring it to an optical film (polarizing film); or applying the aforementioned adhesive composition to an optical film (polarizing film), and then drying to remove the polymerization solvent, etc. to form an adhesive layer on the optical film. In addition, when applying the adhesive, one or more solvents other than the polymerization solvent may be appropriately added.

There is no particular restriction on the thickness of the adhesive layer. However, if it is thin, its adhesion to the image display portion will be reduced, or it may be prone to peeling off when heated and shrunk. On the other hand, if it is thick, in a humidified environment where there is a risk of oil or emulsion components coming into contact with the elastic intermediate layer, these components may be easily absorbed by the adhesive layer and may be prone to peeling off. Therefore, for example, it is preferably about 10 to 30 μm , and 15 to 20 μm is more preferred.

The aforementioned adhesive layer usually has an oleic acid swelling degree of 100 mass % or more. The smaller the oleic acid swelling degree, the smaller the influence caused by the oleic acid. According to the image display panel with a border frame of the present invention, when the oleic acid swelling degree of the adhesive layer is greater than 130%, or greater than 140%, or further greater than 150%, the influence of the grease or emulsifiable concentrate component on the adhesive layer can be suppressed to be smaller. In addition, when the oleic acid swelling degree of the adhesive layer is greater than 130%, the influence of the grease or emulsifiable concentrate component absorbed by the adhesive layer on other optical components can be reduced. On the other hand, if the oleic acid swelling degree of the adhesive layer increases, the influence of the fat or emulsion component on the adhesive layer will also increase. Therefore, the oleic acid swelling degree should be below 190%, and preferably below 180%.

<Image display section>

The image display unit is formed by the above-mentioned optical film (including at least one polarizing film) and a part of the image display device. The image display device may be a liquid crystal display device, an organic EL (electroluminescent) display device, a PDP (plasma display panel), an electronic paper, etc.

The aforementioned image display unit can be, for example, a liquid crystal unit used in a liquid crystal display device. The liquid crystal unit can be any type of liquid crystal unit such as TN type, STN type, π type, VA type, IPS type, etc.

<Image display panel>

When forming an image display panel, in addition to the aforementioned optical films, other optical films can also be used in accordance with the suitability of each configuration location. For example, in a liquid crystal display panel, at least a polarizing film is configured on the side opposite to the viewing side of the liquid crystal unit, and there is no particular restriction on the polarizing film. In addition, the aforementioned other optical films can be, for example, reflective plates or anti-transmission plates, phase difference films (including 1/2 or 1/4 wavelength plates), viewing angle compensation films, brightness enhancement films, etc., which can be used to form optical layers of liquid crystal display devices, etc. These can be used in one layer or two layers or more.

<Image display device>

The formation of various image display devices such as the liquid crystal display device of the present invention can be carried out according to common knowledge. It is formed by appropriately assembling components such as the lighting system as required and incorporating a driving circuit. Generally speaking, a liquid crystal display device is formed in the following manner: a liquid crystal unit (composed of a glass substrate/liquid crystal layer/glass substrate) is appropriately assembled with polarizing films arranged on both sides thereof and components such as the lighting system as required, and then a driving circuit is incorporated. The aforementioned optical film is arranged on the visual side, and other polarizing films are arranged on the other side. In addition, a suitable liquid crystal display device such as one using a backlight or a reflector in the lighting system can be formed in the liquid crystal display device. Furthermore, when forming a liquid crystal display device, appropriate parts such as a diffusion plate, an anti-glare layer, an anti-reflection film, a protective plate, a prism array, a lens array sheet, a light diffusion plate, a backlight, etc. can be arranged in one or more layers at appropriate positions.

Implementation example

The present invention is specifically described below using manufacturing examples and embodiments, but the present invention is not limited to these embodiments. As for the parts and % in each example, they are all based on weight. Below, the room temperature conditions not specifically specified are all 23°C and 65%RH.

<Determination of the weight average molecular weight of (meth)acrylic acid polymer (A)>

The weight average molecular weight (Mw) of (meth)acrylic acid polymers is measured by GPC (gel permeation chromatography). Mw/Mn is also measured in the same way.

‧Analysis device: HLC-8120GPC manufactured by Tosoh Corporation

‧Column: Made by Tosoh, G7000H _XL +GMH _XL +GMH _XL

‧Column size: 7.8mmφ×30cm each, totaling 90cm

‧Column temperature: 40℃

‧Flow rate: 0.8mL/min

‧Injection volume: 100 μ L

‧Solvent: Tetrahydrofuran

‧Detector: Differential refractometer (RI)

‧Standard sample: polystyrene

<Adjusting optical films>

The optical films A to D used in the embodiments, comparative examples and reference examples are prepared in the following manner.

(Making thin polarizers)

A single side of an amorphous isophthalic acid copolymer polyethylene terephthalate (IPA copolymer PET) film substrate (thickness: 100 μm ) having a water absorption rate of 0.75% and a Tg of 75°C was subjected to a corona treatment, and an aqueous solution containing polyvinyl alcohol (polymerization degree 4200, saponification degree 99.2 mol%) and acetoacetyl-modified PVA (polymerization degree 1200, acetoacetyl modification degree 4.6%, saponification degree 99.0 mol% or more, manufactured by Nippon Synthetic Chemical Industries, Ltd., trade name "Gohsefimer Z200") in a ratio of 9:1 was applied to the corona treated side at 25°C and dried to form a PVA-based resin layer with a thickness of 11 μm , thereby producing a laminate.

The obtained laminate was subjected to free-end uniaxial stretching 2.0 times in the longitudinal direction (long side direction) between rollers with different peripheral speeds in an oven at 120°C (in-air assisted stretching treatment).

Next, the laminate was immersed in an insolubilizing bath (boric acid aqueous solution obtained by mixing 4 parts of boric acid with 100 parts of water) at a liquid temperature of 30°C for 30 seconds (insolubilizing treatment).

Next, while immersing it in a dyeing bath at a liquid temperature of 30°C, the iodine concentration and immersion time are adjusted so that the polarizing plate has a predetermined transmittance. In this embodiment, it is immersed in an iodine aqueous solution obtained by mixing 0.2 parts of iodine and 1.0 parts of potassium iodide with respect to 100 parts of water for 60 seconds (dyeing treatment).

Then, immerse it in a crosslinking bath (boric acid aqueous solution obtained by mixing 3 parts of potassium iodide and 3 parts of boric acid with 100 parts of water) at a liquid temperature of 30°C for 30 seconds (crosslinking treatment).

Afterwards, the laminate was immersed in a boric acid aqueous solution at a temperature of 70°C (aqueous solution obtained by mixing 4 parts of boric acid and 5 parts of potassium iodide with 100 parts of water), while being uniaxially stretched in the longitudinal direction (long side direction) between rollers of different peripheral speeds to achieve a total stretching ratio of 5.5 times (stretching in water).

Afterwards, the laminate was immersed in a cleaning bath (an aqueous solution obtained by mixing 4 parts of potassium iodide with 100 parts of water) at a liquid temperature of 30°C (cleaning treatment).

In the above manner, an optical thin film laminate including a polarizer with a thickness of 5 μm was obtained.

(Transparent protective film)

Acrylic film 1: A 40 μm thick (meth) acrylic resin film having a lactone ring structure was used after the easy-to-bond surface was subjected to corona treatment.

Acrylic film 2: A 30 μm thick (meth) acrylic resin film having a lactone ring structure was used after the easy-to-bond surface was subjected to a corona treatment.

TAC film: Use 40μm thick cellulose triacetate film after saponification.

(Manufacturing adhesive for transparent protective film)

10 parts of N-hydroxyethylacrylamide, 30 parts of acrylamide, 45 parts of 1,9-nonanediol diacrylate, 10 parts of an acrylic acid oligomer obtained by polymerizing (meth)acrylic acid monomers (ARUFONUP1190, manufactured by Toagosei Co., Ltd.), 3 parts of a photopolymerization initiator (IRGACURE 907, manufactured by BASF), and 2 parts of a polymerization initiator (KAYACURE DETX-S, manufactured by Nippon Kayaku Co., Ltd.) were mixed to prepare a UV-curable adhesive.

(Phase difference film)

The first phase difference film: a cyclic olefin film with a thickness of 18μm is used (refractive index characteristics: nx>ny>nz, in-plane phase difference: 116nm).

Second phase difference film: Use modified polyethylene film with a thickness of 6μm (refractive index characteristics: nz>nx>ny, in-plane phase difference: 35nm).

<Single-sided protective polarizing film>

On the surface of the polarizer of the optical film laminate, the UV curable adhesive a is applied so that the thickness of the cured adhesive layer becomes 1 μm , and the transparent protective film (thickness 40 μm : acrylic film 1 or TAC film) is attached, and then UV rays are irradiated as active energy rays to cure the adhesive. The UV irradiation is performed using a gallium-filled metal halogen lamp, irradiation device: Light HAMMER10 manufactured by Fusion UV Systems, Inc., bulb: V bulb, peak illuminance: 1600mW/ ^cm2 , cumulative irradiation dose 1000/mJ/ ^cm2 (wavelength 380~440nm), and the UV irradiance is measured using the Sola-Check system manufactured by Solatell. The amorphous PET substrate is then peeled off to produce a single-sided protective polarizing film with a thickness of 46 μm using a thin polarizer.

The single-sided protected polarizing film 1 using the aforementioned acrylic film 1 is used to prepare the single-sided protected polarizing film with phase difference film described below.

When using the aforementioned TAC film, it is directly used as a single-sided protective polarizing film 2.

<Single-sided protective polarizing film with phase difference film>

The first phase difference film and the second phase difference film are sequentially bonded to the thin polarizer side of the aforementioned single-sided protective polarizing film 1, thereby obtaining a single-sided protective polarizing film with a phase difference film having a thickness of 72 μm . The bonding is the same as above, using an ultraviolet curing adhesive a to form an adhesive layer with a thickness of 1 μm . In addition, the first phase difference film is bonded so that the slow axis is 0° relative to the absorption axis of the polarizer, and the slow axis of the second phase difference film is 90° relative to the absorption axis of the polarizer.

<Production of double-sided protective polarizing film>

A 45 μm thick polyvinyl alcohol film was stretched to 3 times while being dyed in a 0.3% iodine solution at 30°C for 1 minute between rollers with different speed ratios. Afterwards, it was stretched to a total stretching ratio of 6 times while being immersed in an aqueous solution containing 4% boric acid and 10% potassium iodide at 60°C for 0.5 minutes. Then, it was washed by immersion in an aqueous solution containing 1.5% potassium iodide at 30°C for 10 seconds, and then dried at 50°C for 4 minutes to obtain a polarizer with a thickness of 18 μm . The TAC film (40 μm thick cellulose triacetate film after saponification) was adhered to one side of the polarizer using a polyethylene glycol adhesive (each with a thickness of 1 μm ) and an acrylic film 2 with a thickness of 30 μm was adhered to the other side to produce a double-sided protective polarizing film with a thickness of 90 μm .

<Production of thin film with surface treatment layer: ARTAC: thickness 44 μm >

A 40 μm thick cellulose triacetate film was sputtered to form an antireflection layer with a thickness of 4 μm .

<Production of thin film with surface treatment layer: ARTAC: thickness 84 μm >

A cellulose triacetate film with a thickness of 80 μm was sputtered to form an antireflection layer with a thickness of 4 μm .

<Preparation of a film with a surface treatment layer: LCTAC (thickness 42 μm )>

A 40 μm thick cellulose triacetate film was coated to form a 2 μm thick liquid crystal phase difference layer.

<Preparing adhesive layer A>

(Preparation of acrylic polymer)

A monomer mixture containing 100 parts of n-butyl acrylate and 5 parts of acrylic acid was fed into a 4-necked flask equipped with a stirring blade, a thermometer, a nitrogen inlet tube, and a cooler. 0.1 parts of 2,2'-azobisisobutyronitrile as a polymerization initiator and 100 parts of ethyl acetate were fed to 100 parts of the above-mentioned monomer mixture (solid component), and nitrogen was introduced while slowly stirring to replace the nitrogen. The liquid temperature in the flask was maintained at around 55°C, and the polymerization reaction was carried out for 8 hours to prepare a solution of an acrylic polymer with a weight average molecular weight (Mw) of 1.6 million.

(Preparation of adhesive composition)

0.45 parts of isocyanate crosslinking agent (Coronate L, trihydroxymethylpropane diisocyanate toluene ester, manufactured by Tosoh) was mixed with 100 parts of the solid content of the acrylic polymer solution obtained above to prepare a solution of acrylic adhesive composition.

(Forming adhesive layer)

Next, the solution of the acrylic adhesive composition was applied onto one side of a polyethylene terephthalate film (separation film: MRF38 manufactured by Mitsubishi Chemical Polyester Film Co., Ltd.) treated with a silicone release agent so that the thickness of the adhesive layer after drying became 23 μm or 12 μm, and dried at 155°C for 1 minute to form an adhesive layer A on the surface of the separation film.

The polarizing film and the film with the surface treatment layer are laminated with the following structure to prepare optical films A to F. The lamination is performed by laminating the triacetate cellulose film side of the film with the surface treatment layer through the adhesive layer A. The lamination of the single-sided protected polarizing film with the phase difference film is performed by laminating the adhesive layer A on the acrylic film 1 side. The lamination of the double-sided protected polarizing film and the single-sided protected polarizing film 2 is performed by laminating the adhesive layer A on the TAC film side.

Optical film A (total thickness 128 μm ): ARTAC (thickness 44 μm )/adhesive layer A (thickness 12 μm )/single-sided protected polarizing film with phase difference film (thickness 72 μm ).

Optical film B (total thickness 179 μm ): ARTAC (thickness 84 μm )/adhesive layer A (thickness 23 μm )/single-sided protected polarizing film with phase difference film (thickness 72 μm ).

Optical film C (total thickness 244 μm ): ARTAC (thickness 84 μm )/adhesive layer A (thickness 23 μm )/LCTAC (thickness 42 μm )/adhesive layer A (thickness 23 μm )/single-sided protected polarizing film with phase difference film (thickness 72 μm ).

Optical film D (total thickness 72 μm ): single-sided protected polarizing film with retardation film (thickness 72 μm ).

Optical film E (total thickness 262 μm ): ARTAC (thickness 84 μm )/adhesive layer A (thickness 23 μm )/LCTAC (thickness 42 μm )/adhesive layer A (thickness 23 μm )/double-sided protected polarizing film (thickness 90 μm ).

Optical film F (total thickness 244 μm ): ARTAC (thickness 84 μm )/adhesive layer A (thickness 23 μm )/LCTAC (thickness 42 μm )/adhesive layer A (thickness 23 μm )/single-sided protected polarizing film 2 (thickness 72 μm ).

Implementation Example 1

(Preparation of acrylic polymer)

A monomer mixture containing 81.9 parts of n-butyl acrylate, 13.2 parts of benzyl acrylate, 0.1 parts of 4-hydroxybutyl acrylate, and 4.8 parts of acrylic acid was added to a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen inlet tube, and a cooler. 0.1 parts of 2,2'-azobisisobutyronitrile as a polymerization initiator and 100 parts of ethyl acetate were added to 100 parts of the above-mentioned monomer mixture (solid component). After nitrogen substitution was performed while slowly stirring, the liquid temperature in the flask was maintained at around 55°C, and the polymerization reaction was carried out for 8 hours to prepare a solution of an acrylic polymer with a weight average molecular weight (Mw) of 1.6 million.

(Preparation of adhesive composition)

0.2 parts of oligomeric silane coupling agent (X-41-1810 manufactured by Shin-Etsu Chemical Co., Ltd.) and 0.45 parts of isocyanate crosslinking agent (Coronate L manufactured by Tosoh Co., Ltd., toluene trihydroxymethyl propane diisocyanate) were mixed with 100 parts of the solid content of the acrylic polymer solution obtained above to prepare a solution of an acrylic adhesive composition.

(Forming adhesive layer)

Next, the solution of the acrylic adhesive composition was applied onto one side of a polyethylene terephthalate film treated with a silicone release agent (separation film: MRF38 manufactured by Mitsubishi Chemical Polyester Film Co., Ltd.) so that the thickness of the adhesive layer after drying became 20 μm, and dried at 155°C for 1 minute to form an adhesive layer B on the surface of the separation film.

(Preparation of optical films with adhesive layers and production of image display panels)

Prepare the image display unit (including a liquid crystal unit with a diagonal size of 15 inches: thickness 300 μm ).

The above-prepared adhesive layer B is laminated to the single-sided protective polarizing film side of the phase difference film of the above-prepared optical film A, and an optical film with an adhesive layer (a polarizing film with short and long sides 4 mm shorter than the above-mentioned liquid crystal unit) is prepared. After peeling off the separation film from the optical film with an adhesive layer, the above-mentioned optical film A (the second phase difference film side) is laminated to the visual side of the above-mentioned image display part through the adhesive layer B using a laminating machine to produce an image display panel (liquid crystal display panel). Then, an autoclave treatment is performed at 50°C and 0.5MPa for 15 minutes to make the above-mentioned optical film A completely adhere to the image display part. Then, the obtained image display panel is laser cut into a 15-inch size.

(Create an image display panel with a border)

Prepare a rubber molded product with a width of 1mm and a height of 5mm processed according to the outer edge of the aforementioned image display panel (15-inch size) (the total width of the retaining part is 1.5mm, there are 6 convex parts, such as the part in Figure 4, and one side of the elastic middle layer is 5cm from both sides) as the elastic middle layer.

In addition, a resin plate (frame) with a width of 1mm and a height of 3mm and metal splash-coated is prepared as an outer frame (integrated with a concave frame that can be embedded in the panel) according to the above-mentioned image display panel (15-inch size).

The elastic middle layer is mounted to the frame body integrated with the outer frame, and then the image display panel is assembled (the gap is set to be less than 1 mm), and the image display panel with a frame is manufactured, in which the elastic middle layer and the outer frame are mounted in sequence on the outer side of the end surface of the image display device as shown in FIG2 (FIG. 2A, FIG2B). In the obtained image display panel with a frame, the elastic middle layer is set to protrude 1 mm from the outermost surface of the visual side of the image display panel (optical film A). The elastic middle layer is a structure that contacts the end surface of the image display panel. The outer frame is fixed to the elastic middle layer by an adhesive.

Implementation Examples 2 to 33 and Comparative Examples 1 to 7

In Example 1, the composition or ratio of the monomer mixture used to prepare the acrylic polymer, the type or blending amount of the silane coupling agent used to prepare the adhesive composition, the type or blending amount of the crosslinking agent, or the thickness of the formed adhesive layer are changed to those shown in Table 1. Otherwise, the adhesive layer B is formed in the same manner as in Example 1. Furthermore, using the adhesive layer B obtained above and the optical films A to F shown in Table 1, an optical film with an adhesive layer is prepared in the same manner as in Example 1 to produce an image display panel. Furthermore, an image display panel with a border frame is produced in the same manner as in Example 1.

In addition, when using optical film E, adhesive layer B is attached to the sides of the double-sided protective polarizing film to prepare an optical film with an adhesive layer, and when using optical film F, adhesive layer B is attached to the two sides of the single-sided protective polarizing film to prepare an optical film with an adhesive layer.

However, in Example 30, an image display panel with a frame having a structure shown in FIG3 (FIG. 3A, FIG3B) is manufactured. In the image display panel with a frame, a resin plate (frame) with a width of 20 mm and a height of 2 mm and a metal splash coating is prepared according to the above-mentioned image display panel (15-inch size) as an inner frame and assembled. The elastic middle layer is set to have a gap of 15 mm with the end face of the above-mentioned image display panel. The outer frame and the above-mentioned elastic middle layer are used to ensure the size of the above-mentioned gap. The above-mentioned outer frame is fixed to the above-mentioned elastic middle layer by an adhesive. The above-mentioned inner frame is fixed to the end of the outermost surface of the above-mentioned image display panel and the above-mentioned elastic middle layer by an adhesive.

In addition, the adhesive composition used to form the adhesive layer of Comparative Example 3 is prepared according to the following method.

A monomer mixture consisting of 67 parts of 2-ethylhexyl acrylate (2EHA), 15 parts of 2-hydroxyethyl acrylate (HEA) and 18 parts of N-vinyl-2-pyrrolidone (NVP) was mixed with 0.050 parts of 1-hydroxycyclohexyl phenyl ketone (trade name: IRGACURE184, manufactured by BASF) and 0.050 parts of 2,2-dimethoxy-1,2-diphenylethan-1-one (trade name: IRGACURE651, manufactured by BASF) as a photopolymerization initiator, and then irradiated with ultraviolet light until the viscosity (measurement conditions: BH viscometer No. 5 rotor, 10 rpm, measurement temperature 30°C) reached about 20 Pa‧s, thereby obtaining a prepolymer composition (polymerization rate: 9%) in which part of the above monomer components were polymerized. Next, 0.09 parts of hexanediol diacrylate (HDDA) was added to the prepolymer composition and mixed to obtain an adhesive composition. The adhesive composition was applied to the peeling-treated surface of a release film (trade name "MRF#38", manufactured by Mitsubishi Resin Co., Ltd.) in a manner such that the thickness became 20 μm to form an adhesive composition layer. Then, the surface of another adhesive composition layer was attached to the peeling-treated surface of a release film ("MRN#38", manufactured by Mitsubishi Resin Co., Ltd.), and ultraviolet rays were irradiated under the conditions of illumination: 4mW/ ^cm2 , light quantity: 1200mJ/ ^cm2 to harden the light and form an adhesive layer to produce an adhesive sheet.

Reference Example 1 (Making a cover glass and image display panel with a frame)

Using the same image display panel as that prepared in Example 1, an image display panel with a frame having the structure shown in FIG5 is prepared.

The outer frame is prepared in the same manner as that used in Example 1.

The cover glass is a 1500 μm thick tempered glass prepared to be formed according to the aforementioned image display panel (15-inch size).

The aforementioned outer frame is installed on the outer side of the end surface of the aforementioned image display panel for assembly. The aforementioned outer frame is fixed to the aforementioned image display panel by an adhesive. The aforementioned cover glass is bonded by an adhesive layer (LUCIACS CS9864 manufactured by Nitto Denko Corporation).

The following evaluations were performed on the image display panels with borders obtained in the above-mentioned embodiments, comparative examples and reference examples. The evaluation results are listed in Table 1.

<Drug testing when moistened>

Use a 2mL dropper to drop 10mL of the following medicine on the inner side (entire) of the elastic middle layer (in the reference example, the outer image frame) of the obtained framed image display panel.

Oleic acid: Oleic acid manufactured by Wako Pure Chemical Industries, Ltd. (grade 1, containing 65%).

Vaseline moisturizing lotion: Unilever's UJ body lotion COAB (containing 63% water and 26% glycerin).

Sunscreen: EDGEWELL PERSONAL CARE Banana Boat Sunscreen Lotion SPF 30.

After dripping the drug, the image display panel with a frame was stored at 65℃ 90%RH for 72 hours and then placed at room temperature (23℃). Then, the optical film with the adhesive layer was removed from the image display panel with a frame, and the appearance was observed with the naked eye and the peeling of the adhesive layer B was evaluated according to the following criteria.

(Evaluation criteria)

◎: No peeling.

○: No peeling, the end is swollen due to rubber expansion.

△: Minor peeling below 0.5mm.

NG: There is peeling (peeling: mm is also recorded in Table 1).

<Determination of oleic acid swelling>

The adhesive layer B formed on the surface of the separation film used in each example was cut into 20mm×40mm and made into a sample and its mass (W1) was measured. Then, the sample was immersed in oleic acid at 60℃ and 90% humidity for 24 hours, the sample was taken out of the oleic acid, and the sample surface was washed with ethanol, and then dried at 110℃ for 3 hours. The mass of the dried sample (W3) was measured, and the oleic acid swelling rate of the acrylic adhesive was calculated using the following formula (2). The mass of the separation film of the sample (W2) was measured separately.

Swelling rate (%) = {(W3-W2)/(W1-W2)}×100

Table 1 shows the following: MA: methyl acrylate, EA: ethyl acrylate, BA: n-butyl acrylate, MMA: methyl methacrylate, 2EHA: 2-ethylhexyl acrylate, Viscoat 3F: 2,2,2-trifluoroethyl acrylate, BzA: benzyl acrylate, 4HBA: 4-hydroxybutyl acrylate, HEA: 2-hydroxyethyl acrylate, NVP: N-vinylpyrrolidone, AA: acrylic acid, MEA: methoxyethyl acrylate, SAT10: SAT10 manufactured by Kaneka, KBM403: KBM-403 manufactured by Shin-Etsu Chemical, KBM573: KBM-573 manufactured by Soken Chemical Co., Ltd., A100: A100 manufactured by Soken Chemical Co., Ltd. (silane coupling agent containing acetyl groups), X-41-1810: oligomeric silane coupling agent containing hydroxyl groups manufactured by Shin-Etsu Chemical Co., Ltd., X-41-1056: oligomeric silane coupling agent containing epoxy groups manufactured by Shin-Etsu Chemical Co., Ltd., C/HX: isocyanate crosslinking agent (CORONATE manufactured by Tosoh Corporation) HX, isocyanurate of hexamethylene diisocyanate), TETRAD C: epoxy crosslinker (TETRAD C/1,3-bis(N,N-epoxypropylaminomethyl)cyclohexane manufactured by Mitsubishi Gas Chemical Co., Ltd.), C/L: isocyanate crosslinker (CORONATE L manufactured by Tosoh Co., Ltd., toluene trihydroxymethylpropane diisocyanate), D160N: isocyanate crosslinker (Takenate D160N manufactured by Mitsui Chemicals Co., Ltd., toluene trihydroxymethylpropane diisocyanate) HDDA: hexanediol diacrylate.

1: Image display unit

2: Optical films (including polarizing films)

3: Adhesive layer (image display side)

4: Elastic middle layer

5: External border

41:Maintenance Department

A: Image display panel

a: The most superficial

t: distance

Claims (17)

An image display panel with a frame is characterized in that: it has an image display panel, a flexible middle layer and an external frame, the image display panel has an image display portion and an optical film disposed on the visual side of the image display portion through an adhesive layer, the flexible middle layer is disposed on at least a portion of the outer side of the end surface of the image display panel and protrudes more than the outermost surface of the visual side of the image display panel , and the width is less than 5 mm; the outer frame is arranged outside the elastic middle layer and does not cover the elastic middle layer, and the width is less than 5 mm; the elastic middle layer protrudes further toward the visual side of the image display panel than the outer frame; the optical film has a polarizing film; the distance between the outermost surface of the visual side of the image display panel and the adhesive layer is 75 μ m or more; the adhesive layer is formed by the following adhesive composition, the adhesive composition contains a (meth) acrylic polymer (A) as a base polymer and contains a silane coupling agent (B), but does not contain: a polyether compound having a polyether skeleton and a reactive silyl group at at least one end; wherein the (meth) acrylic polymer (A) contains 80% by mass or more of a (meth) acrylic acid alkyl ester having an alkyl group with 1 to 4 carbon atoms as a monofunctional monomer unit, and the (meth) acrylic polymer (A) contains 4 to 60% by mass of a (meth) acrylic acid alkyl ester having an alkyl group with 1 to 4 carbon atoms other than n-butyl acrylate and 30% by mass or more of n-butyl acrylate as the above-mentioned monofunctional monomer unit. An image display panel with a frame is characterized in that: it has an image display panel, a flexible middle layer and an external frame, the image display panel has an image display portion and an optical film disposed on the visual side of the image display portion through an adhesive layer, the flexible middle layer is disposed on at least a portion of the outer side of the end surface of the image display panel and protrudes more than the outermost surface of the visual side of the image display panel , and the width is less than 5 mm; the outer frame is arranged outside the elastic middle layer and does not cover the elastic middle layer, and the width is less than 5 mm; the elastic middle layer protrudes further toward the visual side of the image display panel than the outer frame; the optical film has a polarizing film; the distance between the outermost surface of the visual side of the image display panel and the adhesive layer is 75 μ m or more; the adhesive layer is formed by the following adhesive composition, the adhesive composition contains a (meth) acrylic polymer (A) as a base polymer and contains a silane coupling agent (B), but does not contain: a polyether compound having a polyether skeleton and a reactive silyl group at at least one end; wherein the (meth) acrylic polymer (A) contains 80% by mass or more of a (meth) acrylic acid alkyl ester having an alkyl group with 1 to 4 carbon atoms as a monofunctional monomer unit, and the (meth) acrylic polymer (A) contains 15% to 60% by mass of an acrylic acid alkyl ester having an alkyl group with 1 to 4 carbon atoms other than n-butyl acrylate and 30% by mass or more of n-butyl acrylate as the above-mentioned monofunctional monomer unit. An image display panel with a frame is characterized in that: it has an image display panel, a flexible middle layer and an external frame, the image display panel has an image display portion and an optical film disposed on the visual side of the image display portion through an adhesive layer, the flexible middle layer is disposed on at least a portion of the outer side of the end surface of the image display panel and protrudes more than the outermost surface of the visual side of the image display panel , and the width is less than 5 mm; the outer frame is arranged outside the elastic middle layer and does not cover the elastic middle layer, and the width is less than 5 mm; the elastic middle layer protrudes further toward the visual side of the image display panel than the outer frame; the optical film has a polarizing film; the distance between the outermost surface of the visual side of the image display panel and the adhesive layer is 75 μ m or more; the adhesive layer is formed by the following adhesive composition, the adhesive composition contains a (meth) acrylic polymer (A) as a base polymer and contains a silane coupling agent (B), but does not contain: a polyether compound having a polyether skeleton and a reactive silyl group at at least one end; wherein the (meth) acrylic polymer (A) contains 80% by mass or more of a (meth) acrylic acid alkyl ester having an alkyl group with 1 to 4 carbon atoms as a monofunctional monomer unit, and the (meth) acrylic polymer (A) contains 5 to 15% by mass of a methacrylic acid alkyl ester having an alkyl group with 1 to 4 carbon atoms and 70% by mass or more of n-butyl acrylate as the above-mentioned monofunctional monomer unit. An image display panel with a frame is characterized in that: it has an image display panel, a flexible middle layer and an external frame, the image display panel has an image display portion and an optical film disposed on the visual side of the image display portion through an adhesive layer, the flexible middle layer is disposed on at least a portion of the outer side of the end surface of the image display panel and protrudes more than the outermost surface of the visual side of the image display panel , and the width is less than 5 mm; the outer frame is arranged outside the elastic middle layer and does not cover the elastic middle layer, and the width is less than 5 mm; the elastic middle layer protrudes further toward the visual side of the image display panel than the outer frame; the optical film has a polarizing film; the distance between the outermost surface of the visual side of the image display panel and the adhesive layer is 75 μ m or more; the adhesive layer is formed by the following adhesive composition, the adhesive composition contains a (meth) acrylic polymer (A) as a base polymer and contains a silane coupling agent (B), but does not contain: a polyether compound having a polyether skeleton and a reactive silyl group at at least one end; wherein the (meth) acrylic polymer (A) contains 80% by mass or more of any one monomer selected from (meth) acrylic alkyl esters having an alkyl group with 1 to 4 carbon atoms and acrylonitrile as a monofunctional monomer unit; and the (meth) acrylic polymer (A) contains 70% by mass or more of the aforementioned (meth) acrylic alkyl esters having an alkyl group with 1 to 4 carbon atoms and 5% by mass or more of acrylonitrile, and contains 70% by mass or more of n-butyl acrylate as the aforementioned monofunctional monomer unit. An image display panel with a frame is characterized in that: it has an image display panel, a flexible middle layer and an outer frame, the image display panel has an image display portion and an optical film disposed on the visual side of the image display portion through an adhesive layer, the flexible middle layer is disposed on at least a portion of the outer side of the end surface of the image display panel and protrudes more than the outermost surface of the visual side of the image display panel. The outer frame is arranged outside the elastic middle layer and does not cover the elastic middle layer, and has a width of less than 5 mm; the elastic middle layer protrudes further toward the visual side of the image display panel than the outer frame; the optical film comprises a polarizing film; the distance between the outermost surface of the visual side of the image display panel and the adhesive layer is 75 μ m or more; the adhesive layer is formed by the following adhesive composition, the adhesive composition contains a (meth) acrylic polymer (A) as a base polymer and contains a silane coupling agent (B), but does not contain: a polyether compound having a polyether skeleton and a reactive silyl group at at least one end; wherein the (meth) acrylic polymer (A) contains 80% by mass or more of a monomer (a) as a monofunctional monomer unit, and the monomer (a) is selected from any one of a (meth) acrylic acid alkyl ester having an alkyl group with 1 to 4 carbon atoms, a (meth) acrylic acid alkoxyalkyl ester, a fluorine-containing monomer and acrylonitrile; and the (meth) acrylic polymer (A) contains 70% by mass or more of a (meth) acrylic acid alkoxyalkyl ester as the monofunctional monomer unit. An image display panel with a border frame as claimed in any one of claims 1 to 5, wherein the polarizing film has a transparent protective film on one or both sides of the polarizing element, and the thickness of the polarizing element is 3~30 μm . An image display panel with a border frame as claimed in any one of claims 1 to 5, wherein the optical film has a surface treatment layer on the outermost surface of the viewing side. An image display panel with a border frame as in any one of claims 1 to 5, wherein the distance between the outermost surface of the viewing side of the image display panel and the adhesive layer is less than 300 μm . An image display panel with a border frame as in any one of claims 1 to 5, wherein the thickness of the adhesive layer is 10-30 μm . An image display panel with a border frame as claimed in any one of claims 1 to 5, wherein the oleic acid swelling degree of the adhesive layer is greater than 130% and less than 190%. An image display panel with a border frame as claimed in any one of claims 1 to 5, wherein the end surface of the image display panel is in contact with the elastic middle layer. The image display panel with a border as claimed in any one of claims 1 to 5 has an inner border on the end face of the image display panel; the inner border is located further inward than the elastic middle layer and is located on the outermost surface of the visual side of the image display panel; the elastic middle layer is more prominent than the inner border. The image display panel with border frame as claimed in any one of claims 1 to 5, wherein the aforementioned silane coupling agent (B) is selected from at least one of an epoxy-containing silane coupling agent (b1) and a butyl-containing silane coupling agent (b2). The image display panel with border as claimed in claim 13, wherein the aforementioned epoxy-containing silane coupling agent (b1) is a low molecular weight epoxy-containing silane coupling agent (b1). The image display panel with border frame as claimed in claim 13, wherein the aforementioned silane coupling agent containing silane groups (b2) is an oligomer type silane coupling agent containing silane groups (b2). An image display panel with a border frame as claimed in any one of claims 1 to 5, wherein the adhesive composition contains a crosslinking agent. An image display device has an image display panel with a border as in any one of claims 1 to 16.

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