JP5048288B2 - Optical member and display panel laminate using the same - Google Patents

Description

  The present invention relates to an optical member provided with an optical film such as an antireflection film, an NIR cut film, a color tone correction film, an electromagnetic wave shielding mesh film, and a display panel laminate in which the optical member is bonded to a display panel.

In recent years, plasma televisions have been rapidly spreading as an alternative to CRT televisions.
In this plasma TV, discharge is generated in a rare gas enclosed in the panel, generally a gas mainly composed of neon, and R, G provided in the cells inside the panel by vacuum ultraviolet rays generated at that time. , B phosphors are issued. In this issuance process, electromagnetic waves and near infrared rays that are unnecessary for the operation of the plasma display (PDP) are emitted at the same time. Therefore, it is necessary to shield them, and various types for shielding such electromagnetic waves and near infrared rays. An optical film is bonded onto the display panel.

  Various pressure-sensitive adhesive sheets have been developed for bonding optical films and bonding optical films and display panels (for example, see Patent Documents 1 to 3 below).

JP 2000-301664 A JP 2001-234129 A JP 2004-359808 A

  When the optical films are bonded to each other, it is preferable to perform an autoclave treatment under high pressure and high temperature in order to increase the adhesive force between the films. In particular, when laminating a mesh-type electromagnetic shielding film that has not been transparentized, it is necessary to perform a transparentizing process that fills the copper foil mesh with a hard thin adhesive without any gaps, so autoclaving is an essential process. .

However, the optical film easily dissolves air, and the optical film subjected to the autoclave treatment dissolves a large amount of air. Therefore, as shown in FIG. 3, when the optical film 8 that has been autoclaved is bonded to the display panel 10 via the adhesive layer 9, air is released from the optical film 8, and the adhesive layer 9 is formed by this air. There is a problem that foaming occurs and a large number of bubbles 11 are generated at the interface between the display panel 10 and the adhesive layer 9, thereby hindering visibility.
In recent years, the display panel may be the outermost surface. In this case, in order to prevent cracking of the display panel, an optical film is bonded to the display panel via a flexible adhesive layer cross-linked with ultraviolet rays. May have absorbability. In this case, since the adhesive layer is flexible, it is particularly easy to foam.

  Therefore, in order to solve the above-described problems, the present invention prevents dissolution of air into the optical film even when autoclaving is performed, and also allows flexible bonding even when bonded to a display panel via a flexible adhesive layer. The object is to provide an optical member that does not cause the agent layer to foam.

  The optical member of the present invention is an optical member in which a sheet on which an inorganic oxide film layer is formed is laminated on an optical film via an adhesive layer that is crosslinked by heating or moisture, and the inorganic oxide film layer is formed. The sheet has an oxygen transmission rate measured by JIS K7126B method (23 ° C., 70%) of 50 or less and a water vapor transmission rate measured by JIS K7129A method (40 ° C., 90%) of 20 or less. Features.

  Thereby, since an inorganic oxide film layer can shield air, even if it carries out an autoclave process, it becomes difficult to melt | dissolve air in an optical film. Moreover, since the pressure-sensitive adhesive crosslinked by heating or moisture is hard and difficult to foam, it is not foamed by air dissolved in the optical film.

The inorganic oxide film layer can be formed of silica (SiO ₂ ), alumina (Al ₂ O ₃ ), or zinc oxide (ZnO).

The adhesive layer crosslinked by heating or moisture preferably has a glass transition temperature (Tg) of −10 ° C. or more and 5 ° C. or less and a thickness of 2 to 50 μm.
When the glass transition temperature and the thickness are in the above ranges, it can be firmly bonded.

Using the above optical member, the sheet side on which the inorganic oxide film layer of this optical member is formed can be laminated on a display panel via an adhesive layer crosslinked with ultraviolet rays to form a display panel laminate.
Thereby, since an inorganic oxide film layer shields air, it does not foam the adhesive bond layer bridge | crosslinked with the ultraviolet-ray, and can form the display panel laminated body excellent in visibility.

In addition, if the holding force is large, the adhesive layer does not conform to the surface unevenness of the display panel and the like, and bubbles tend to remain. Conversely, if the holding force is small, the display panel and the optical member may be misaligned. . The holding force is generally inversely proportional to the thickness.
As a result of intensive studies based on these facts, the adhesive layer crosslinked with ultraviolet rays has a glass transition temperature (Tg) of −10 ° C. or less, a thickness of 100 μm to 2000 μm, and a displacement length of 2 mm to 12 mm. It is preferable that

Hereinafter, the present invention will be described based on embodiments.
However, the embodiment described below is an example of the embodiment of the present invention, and the scope of the present invention is not limited to the following embodiment.

  As shown in FIG. 1, the optical member 1 of the present invention has a configuration in which a sheet 2 on which an inorganic oxide film layer is formed is laminated on an optical film 4 via an adhesive layer 3 that is crosslinked by heating or moisture. It is an optical member.

(Sheet 2 on which an inorganic oxide film layer is formed)
The sheet 2 on which the inorganic oxide film layer is formed has a high gas barrier property and water vapor barrier property by forming the inorganic oxide film layer 2B on one or both sides of the sheet substrate 2A, and is generated from the optical film 4 or the like. Outgassing can be shut off, and the oxygen transmission rate (cc / m ² , 24 hr) measured by JIS K7126B method (23 ° C., 70%) is 50 or less, particularly 10 or less, and JIS K7129A method ( The water vapor transmission rate (g / m ² , 24 hr) measured at 40 ° C. and 90% is 20 or less, particularly 5 or less.

As the sheet base 2A, polyester, (meth) acrylic, polyvinyl butyral (PVB), ethylene vinyl acetate (EVA), polypropylene (PP), polycarbonate, polyamide, etc. are transparent and visible. Those that do not impair sex and the like can be used. A biaxially stretched polyester sheet having rigidity and heat resistance is suitable.
The thickness of the substrate 2A is not particularly limited, but is 5 μm to 200 μm, preferably 12 μm to 100 μm, particularly preferably 25 μm to 50 μm.

The inorganic oxide film layer 2B is a transparent layer formed of an inorganic oxide. For example, silica (SiO ₂ ), alumina (Al ₂ O ₃ ), zinc oxide (ZnO), or two of them are used. It can form from the mixture which consists of the above combination. Of these, zinc oxide (ZnO) is preferable because it has infrared absorptivity.
The thickness of the inorganic oxide film layer 2B is not particularly limited, but is 1.0 nm to 100 nm, preferably 3.0 nm to 50 nm, and particularly preferably 10 nm to 30 nm.

The formation method of the inorganic oxide film layer 2B is not particularly limited, but may be formed by a vacuum deposition method, a physical vapor deposition (PVD) method, a chemical vapor deposition (CVD) method, a sputtering method, a sol-gel method, or the like. it can.
The inorganic oxide film layer 2B can be formed on one side or both sides of the base material, and various inorganic oxide film layers can be formed on the front and back sides.

(Adhesive layer 3 crosslinked by heating or moisture)
The adhesive layer 3 crosslinked by heating or moisture can adhere the adherend firmly and is hard and difficult to foam.
As an adhesive for the main layer 3, an acrylic pressure-sensitive adhesive, a solvent type two-component curable dry laminate adhesive, or the like can be used.
In order to firmly adhere the adherend, the thickness of the main layer 3 is preferably thin, specifically 2 μm to 50 μm, preferably 10 μm to 30 μm, and particularly preferably 20 μm to 25 μm.

The glass transition temperature (Tg) of the adhesive used for the main layer 3 is preferably −10 ° C. to 5 ° C., particularly preferably −10 ° C. to 0 ° C.
The glass transition temperature referred to in the present invention is obtained by substituting the maximum value of Tan δ measured by the dynamic viscoelasticity measurement method, and using viscoelasticity measurement device measurement (for example, Dynamic Analyzer RDAII; manufactured by Rheometrics). The temperature indicating the maximum value of Tan δ when the parallel plate was 25 mmφ, the strain was 2%, and the frequency was 1 Hz was read.

The holding power of the adhesive used for the layer 3 is less than 1 mm, preferably less than 0.5 mm, particularly preferably 0 mm (no deviation).
The holding force referred to in the present invention can be expressed by a time during which a load is applied to the adhesive in the shear direction to generate a shift stress in the thickness direction and the load falls by a load or a shift length within a certain time. For example, if the displacement is large, the holding force is small, and if the displacement is small, the holding force is large, and the adhesive has a high cohesive force.
In the present invention, the holding force is measured by using an SUS plate defined in JIS Z0237, adhered at an area of 20 mm × 20 mm, humidity-controlled overnight at 40 ° C. × 80%, and 500 gf in an environment of 40 ° C. × 80%. The load was applied for 2 hours, and the deviation length or the falling time was measured.

(Optical film 4)
As the optical film 4, a polarizing film, a polarization conversion element, a reflecting plate, a transflective plate, a retardation film, a brightness enhancement film, an optical compensation film protective film, an antireflection (AR) film, an electromagnetic wave shielding film, a near infrared ray (NIR) Various materials such as a cut film, a color tone correction film, and a laminate obtained by combining them can be used.

(Manufacturing method of the optical member 1)
The optical member 1 forms, for example, an adhesive layer 3 by applying an adhesive that crosslinks with heat or moisture on the inorganic oxide film layer 2B of the sheet 2 on which the inorganic oxide film layer is formed, and the optical member 1 is optically coated thereon. The film 4 can be stuck and manufactured by autoclaving (conditions such as 0.5 MPa to 0.8 MPa, 50 ° C. to 80 ° C., 20 minutes to 30 minutes).
In addition, the adhesive layer 3 is an adhesive sheet in which a release film is formed on both sides, the one side is peeled off, and the adhesive layer 3 is attached to the inorganic oxide film layer 2B of the sheet 2 on which the inorganic oxide film layer is formed. The other side can be peeled off, the optical film 4 can be applied, and autoclaved (0.5 MPa to 0.8 MPa, 50 ° C. to 80 ° C., 20 minutes to 30 minutes, etc.).

  In the optical member 1, the adhesive layer 3 is formed on the inorganic oxide film layer 2B, but the adhesive layer 3 may be formed on the surface opposite to the inorganic oxide film layer 2B. It is preferable to form the adhesive layer 3 on the inorganic oxide film layer 2B because the inorganic oxide film layer 2B is difficult to peel off.

(Display panel laminate 7)
A display panel laminate 7 can be formed by bonding the optical member 1 on the display panel 5 via an adhesive layer 6 crosslinked with ultraviolet rays.

(Display panel 5)
The display panel 5 can use a glass plate or the like.

(Adhesive layer 6 crosslinked with ultraviolet rays)
The adhesive layer 6 cross-linked with ultraviolet rays is deformed while conforming to the irregularities on the surface of the adherend in a low temperature environment, and has flexibility in a high temperature environment.
As the adhesive of the main layer 6, a syrup type or hot melt type acrylic adhesive cross-linked with ultraviolet rays can be used.
In order to adhere and adhere to the unevenness of the adherend surface, the thickness of the adhesive layer 6 is preferably formed thick, specifically 100 μm to 2000 μm, preferably 150 μm to 1000 μm, particularly preferably 200 μm to Set to 500 μm.

  The glass transition temperature (Tg) of the adhesive used in the present layer 6 is preferably −10 ° C. or lower, particularly preferably −30 ° C. or lower.

  The holding power of the adhesive used in the main layer 6 is 2 mm to 12 mm, preferably 4 mm to 10 mm, particularly preferably 5 mm to 7 mm.

(Manufacturing method of display panel laminate 7)
The display panel laminate 7 is formed, for example, by applying an adhesive that crosslinks with ultraviolet rays on the sheet 2 on which the inorganic oxide film layer of the optical member 1 is formed, and forming the adhesive layer 6. It can be manufactured by applying and ultraviolet irradiation.
Also, the adhesive layer 6 is an adhesive sheet having a release film formed on both sides thereof, this one side is peeled off, and is attached to the sheet 2 on which the inorganic oxide film layer of the optical member 1 is formed. It is also possible to produce by irradiating UV, irradiating with ultraviolet light.

The optical member of the present invention includes a sheet on which an inorganic oxide film layer is formed. Since this layer can block air, it is possible to prevent the air from being dissolved in the optical film during autoclaving. Moreover, since the adhesive layer crosslinked by heating or moisture is hard, it is difficult to foam and does not hinder visibility.
If this optical member is bonded to a display panel through an adhesive layer crosslinked with a flexible ultraviolet ray to form a display panel laminate, the sheet on which the inorganic oxide film layer is formed is bonded to the optical film with an ultraviolet ray. Since it is between the adhesive layer, the adhesive layer cross-linked with soft ultraviolet rays does not foam, and visibility is not hindered.

  Hereinafter, although an example is described, the present invention is not limited to this.

In Examples and Comparative Examples, an adhesive layer that is crosslinked by heating or moisture is formed using a non-yellowing type adhesive for dry lamination, and an adhesive layer that is crosslinked by ultraviolet rays is formed using the following adhesive sheet. did.
95 parts by weight of 2-ethylhexyl acrylate monomer and 5 parts by weight of methyl methacrylate monomer were mixed, and this was adjusted to an appropriate condition using a polymerization initiator AIBN (Nacalai Tesque 1st grade reagent) in an ethyl acetate solvent. Polymerization was performed to obtain a polymer solution, and ethyl acetate was removed from the solution to obtain a solid acrylate polymer polymer. This polymer had a melt viscosity of 130 ° C. measured by a B-type viscometer of 350,000 mPa · s.
To 100 parts by weight of the solid content of this polymer, 0.3 part by weight of a hydrogen abstraction type photoinitiator benzophenone and 5.0 parts by weight of a polyfunctional monomer (trade name biscoat 295; manufactured by Osaka Organic Chemical Co., Ltd.) were added and melted. did.
This was coated on a surface of 50 μm thick silicone release PET (trade name MRF50; manufactured by Mitsubishi Chemical Polyester Film Co., Ltd.) using a hot melt coater so as to have a thickness of 250 μm. Silicone release PET (trade name: MRF38; manufactured by Mitsubishi Chemical Polyester Film Co., Ltd.) with a thickness of 38 μm is laminated and irradiated with ultraviolet energy (wavelength 365 mm equivalent) with an integrated light amount of 2000 mJ / cm ² using a high-pressure mercury lamp from both sides. To form an adhesive sheet.

Example 1
As a sheet on which an inorganic oxide film layer is formed, a sheet (trade name Fine Barrier AT; manufactured by Reiko Co., Ltd.) obtained by depositing alumina (Al ₂ O ₃ ) on one side of a 25 μm thick biaxially stretched polyester (PET) sheet. Using.
A non-yellowing type adhesive for dry laminating was applied at a thickness of 3 μm on the surface of the sheet where alumina was not deposited, to form an adhesive layer, and a copper mesh was processed on one side of a PET film having a thickness of 100 μm. An electromagnetic shielding film was laminated. At this time, the surface on which the copper mesh was not processed was laminated toward the adhesive layer.

  Next, a non-yellowing dry laminating adhesive is applied to the processed surface of the copper mesh at a thickness of 15 μm, an NIR cut film is laminated thereon, and a non-yellowing dry laminating adhesive is thickened thereon. The film is coated at a thickness of 3 μm, and a color correction film is laminated thereon. Further, a non-yellowing type dry laminating adhesive is coated at a thickness of 3 μm, and an AR film is laminated. After holding for 60 minutes under the conditions of 0.8 ° C. and 0.8 ° C., the optical member was formed by returning to normal temperature and pressure.

(Example 2)
A 3 mm thick soda dime glass is used as a display panel, and a release film on one side of the adhesive sheet is peeled off and stuck on the display panel, and adhered and laminated with a hand roll, and then released on the other side. The mold film was peeled off, and the sheet side on which the inorganic oxide film layer of the optical member of Example 1 was adhered was adhered thereto and adhered and laminated with a hand roll to form a display panel laminate.

(Comparative Example 1)
An optical member was formed in the same manner as in Example 1, except that a biaxially stretched polyester film (trade name T60-25; manufactured by Toray Industries, Inc.) having a thickness of 25 μm was used instead of the sheet on which the inorganic oxide film layer was formed. .

(Comparative Example 2)
A 3 mm thick soda dime glass is used as a display panel, and a release film on one side of the adhesive sheet is peeled off and stuck on the display panel, and adhered and laminated with a hand roll, and then released on the other side. The mold film was peeled off, and the sheet side on which the inorganic oxide film layer of the optical member of Comparative Example 1 was formed was stuck thereon and adhered and laminated with a hand roll to form a display panel laminate.

(Moist heat test)
Examples 1 and 2 and Comparative Examples 1 and 2 were stored for 1 day under environmental conditions of 60 ° C. × 90%, and a wet heat test was performed. Immediately after taking them out, the appearance was visually observed, and when the foam was not foamed, it was evaluated as ◯, and when it was foamed, it was evaluated as x.
The results are shown in Table 1.

Foaming was not observed in the optical member of Example 1 and the display panel laminate of Example 2.
On the other hand, the optical member of Comparative Example 1 and the display panel laminate of Comparative Example 2 foamed and could not be satisfied in appearance.

It is sectional drawing which showed an example of the optical member of this invention typically. It is sectional drawing which showed typically an example of the display panel laminated body of this invention. It is sectional drawing which showed an example of the conventional optical member typically.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Optical member 2 Sheet | seat which formed the inorganic oxide film layer 2A Sheet base material 2B Inorganic oxide film layer 3 Adhesive layer 4 bridge | crosslinked with heating or moisture Optical film 5 Display panel 6 Adhesive layer 7 bridge | crosslinked with ultraviolet rays Display panel Laminated body 8 Optical film 9 Adhesive layer 10 Display panel 11 Air bubbles

Claims (6)

An optical member in which a sheet on which an inorganic oxide film layer is formed is laminated on an optical film via an adhesive layer that is crosslinked by heating or moisture,
The optical film includes a polarizing film, a polarization conversion element, a reflector, a transflective plate, a retardation film, a brightness enhancement film, an optical compensation film protective film, an antireflection (AR) film, an electromagnetic shielding film, and a near infrared (NIR) cut. It is a laminate of either a film, a color tone correction film or a combination thereof,
The sheet on which the inorganic oxide film layer is formed has an oxygen permeability (cc / m ² , 24 hr ) measured by JIS K7126B method (23 ° C., 70%) of 50 or less, and JIS K7129A method (40 ° C. , 90%), an optical member having a water vapor transmission rate ( g / m ² , 24 hr ) of 20 or less. The optical member according to claim 1, wherein the optical member is an optical member heat-treated by an autoclave device. The optical member according to claim 1 or 2 , wherein the inorganic oxide film layer is formed of any one of silica (SiO ₂ ), alumina (Al ₂ O ₃ ), and zinc oxide (ZnO). The optical member according to any one of claims 1 to 3, wherein the adhesive layer crosslinked by heating or moisture has a glass transition temperature (Tg) of -10 ° C to 5 ° C and a thickness of 2 µm to 50 µm. The display panel laminated body which laminated | stacked the sheet | seat side in which the inorganic oxide film layer of the optical member in any one of Claims 1-4 was laminated | stacked on the display panel through the adhesive bond layer bridge | crosslinked with the ultraviolet-ray. The adhesive layer crosslinked with ultraviolet rays has a glass transition temperature (Tg) of −10 ° C. or less, a thickness of 100 μm to 2000 μm , and a holding force measured under the following conditions with a deviation length of 2 mm to 12 mm. The display panel laminate according to claim 5 .
(Retention force measurement)
Using an SUS plate specified in JIS Z0237, adhering it in an area of 20 mm x 20 mm, adjusting the humidity overnight at 40 ° C x 80%, and applying a load of 500 gf in an environment of 40 ° C x 80% for 2 hours, the deviation length This is done by measuring

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