JPH06160631A - Protective plate for optical blank film and optical member - Google Patents

Abstract

(57) Abstract: OBJECTIVE scratch resistance, surface hardness, resistance to moisture permeation, resistance permeability, heat resistance, provides solvent resistance, protective plate of optical Motomaku satisfying the required performance such as dust resistance And an optical member such as a polarizing plate or a retardation plate using the protective plate. [Structure] A protective plate (1) for laminating and adhering to at least one surface of an optical element film (2) made of a polarizing element film or a retardation element film to protect it. This protective plate (1) is an optically isotropic base sheet (11) / metal oxide layer (12) / curable resin cured product layer (13), or an optically isotropic base sheet (11) / curable resin. It is a laminated sheet having a layered structure of a cured product layer (13) / metal oxide layer (12). The metal oxide layer (12) is preferably a layer of silicon oxide represented by SiOx (1 <x <2). An optical member (polarizing plate or retardation plate) is produced by laminating and adhering the protective plate (1) side of the optical isotropic base sheet (11) to at least one surface of the optical element film (2).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a protective plate for laminating and adhering at least one surface of an optical element film made of a polarizing element film or a retardation element film to protect it. It also relates to an optical member using the protective plate.

[0002]

2. Description of the Related Art As is well known, a liquid crystal cell has a structure in which liquid crystal is sealed between two substrates. LCD display panel,
Typically, it is manufactured by laminating a polarizing plate on one surface of a liquid crystal cell and a polarizing plate on the other surface of the liquid crystal cell with a retardation plate interposed therebetween. The retardation plate may be omitted, or a compensating liquid crystal cell may be used instead of the retardation plate. Lamination of a polarizing plate and a retardation plate is usually performed by sticking a polarizing plate with a pressure-sensitive adhesive layer or a retardation plate with a pressure-sensitive adhesive layer to an object.

As the above-mentioned polarizing plate or retardation plate, one in which a cellulose triacetate film as a protective plate is laminated on both sides of a polarizing film or a retardation film is generally used.

Japanese Unexamined Patent Publication (Kokai) No. 58-50501 discloses a polarizing plate having a layer of saponified ethylene-vinyl acetate copolymer on at least one surface of a polarizing film.
In the explanation of the prior art, cellulose triacetate film (cellulose triacetate film) is most often used for the protection of polarizing film, polycarbonate film, polymethyl acrylate film, Since it is difficult to use a polyvinyl chloride film or the like as compared with the cellulose triacetate film, it is described that it is rarely used in practice.

In Japanese Patent Laid-Open No. 57-64710, a vinyl alcohol polymer polarizing film and a holding plate or a protective film are laminated via an adhesive layer made of a partially saponified ethylene-vinyl acetate copolymer. A polarizing plate is shown, and as a protective plate, a film of cellulose ester type (cellulose diacetate, cellulose triacetate, cellulose acetate butyrate, etc.), polystyrene type, acrylic type, polyester type, polycarbonate type, polyolefin type, polyamide type, etc. , Sheets, plates, and the like, and protective films include nitrocellulose, polyolefin resins, vinyl chloride copolymers, vinylidene chloride polymers, and the like.

[0006]

As described above, the protective plate for producing a polarizing plate or for producing a retardation plate, which is currently in practical use, is practically limited to the cellulose triacetate film.

However, since the cellulose triacetate film lacks in scratch resistance, surface hardness, moisture permeation resistance, air permeation resistance and the like, the polarizing plate and the retardation plate may be handled during handling or after the liquid crystal display panel is manufactured. The surface of the retardation film may be damaged, or the performance of the polarizing element film or the retardation element film may be deteriorated with time, and it is becoming difficult to meet the demand for higher sophistication.

The present inventors have examined a protective plate having a layer of a curable resin cured product on the surface of an optically isotropic sheet such as a cellulose triacetate film or a polycarbonate film, and have found scratch resistance, surface hardness and moisture permeability resistance. However, it was not yet completely satisfied.

Under such circumstances, the present invention is for optical use which satisfies the required performances such as scratch resistance, surface hardness, moisture resistance, heat resistance, air resistance, heat resistance, solvent resistance and dust resistance. An object of the present invention is to provide a protective film for a film and an optical member such as a polarizing plate or a retardation plate using the protective plate.

[0010]

The protective plate for an optical element film of the present invention is an optical element film made of a polarizing element film or a retardation element film.
A protective plate (1) for laminating and adhering to at least one surface of (2) for protection thereof, wherein the protective plate (1) is an optically isotropic base sheet (11) / metal oxide layer (12). ) / Curable resin cured product layer (13), or a laminated sheet having a layer structure of optically isotropic base sheet (11) / curable resin cured product layer (13) / metal oxide layer (12) It is characterized by.

Further, the optical member of the present invention comprises an optical isotropic base sheet (11) of the above-mentioned protective plate (1) on at least one surface of an optical element film (2) comprising a polarizing element film or a retardation element film. The side is laminated and adhered.

The present invention will be described in detail below. In this specification, the terms film, sheet and plate are used, but there is no particular distinction between them.

The protective plate (1) of the present invention comprises an optically isotropic base sheet (11) / metal oxide layer (12) / curable resin cured material layer (13), optically isotropic base sheet (11). / Curable resin cured product layer (1
3) / Metal oxide layer (12), which is a laminated sheet having any one of the following layer configurations. In this case, the anchor coating layer (ac) can be interposed between the optically isotropic base sheet (11) and the curable resin cured product layer (13).

As the optically isotropic base sheet (11), a film having a necessary mechanical strength, for example, a hard polyvinyl chloride film, a polyvinylidene chloride film, a polycarbonate film, a polystyrene film, a polyester film, a polysulfone film, a polysulfone film, -4-methylpentene film, polyphenylene oxide film, polyether sulfone film, polyarylate film, polyvinyl alcohol film, ethylene-
Vinyl alcohol copolymer films, cellulose films (cellulose triacetate, cellulose diacetate, cellulose acetate butyrate, etc.) are used. The optically isotropic base sheet (11) is not limited to a single layer,
It may have multiple layers.

Since this base sheet (11) is required to have optical isotropy, it is a film having a retardation value of 30 nm or less, particularly 20 nm or less and a visible light transmittance of 75% or more. To use. Such an optically isotropic base sheet (11) can be obtained by forming a film by a casting method, but if the retardation value and the visible light transmittance satisfy the above conditions, an extrusion method, etc. The molding method of can also be adopted. The thickness of the optically isotropic base sheet (11) is preferably about 5 to 200 μm.

Examples of the metal oxide layer (12) include oxide layers of silicon, zinc, magnesium, etc., and cost, transparency, adhesion to the optically isotropic base sheet (11), non-coloring property, etc. Considering all of the above points, especially SiOx
(However, a layer of silicon oxide represented by 1 <x <2) is preferable. Silicon dioxide represented by SiO2 is SiO
Compared with ₂ (1 <x <2), the properties are insufficient.
This metal oxide layer (12) is a non-conductive layer.

As the curable resin cured product layer (13), a heat curable resin cured product layer (phenoxy ether type crosslinkable resin,
Epoxy resin, acrylic resin, acrylic silicone resin, silicone resin, melamine resin, phenol resin, urethane resin, rubber resin, etc., UV-curable resin cured material layer (phosphazene resin, acrylic resin, etc.) And so on. The thickness is often about 0.5 to 50 μm. The curable resin cured product layer (13) also needs to have optical isotropy.

Protective plate having the above-mentioned or layer structure
(1) It should be noted that the retardation value and the visible light transmittance of the whole are 30 nm or less and 75% or less, respectively.

The metal oxide layer (12) is usually formed on the lower layer (in the above case, the optically isotropic base sheet (11), in the case of the curable resin cured product layer (13)) by a vapor deposition method. It The curable resin cured product layer (13) is usually a lower layer (a metal oxide layer (12) in the above case by the casting method, an optically isotropic base sheet (11) or an anchor coating layer (ac) in the case of the above). ) Formed on.

The protective plate (1) having such a layer structure is
The optical element film (2) made of a polarizing element film or a retardation element film is laminated and adhered to at least one surface (usually both surfaces) with an appropriate adhesive or pressure-sensitive adhesive, whereby an objective optical member, that is, A polarizing plate or a retardation plate is produced. In this case, the side of the optically isotropic base sheet (11) is the side of the elementary film (2).

Here, as the polarizing film, vinyl alcohol type polymer / iodine type, vinyl alcohol type polymer / 2
Coloring dye type, vinyl alcohol type polymer / polyene type,
Examples thereof include polyvinyl halide / polyene type and polyacrylonitrile / polyene type.

Examples of the retardation film include a uniaxially stretched (and optionally biaxially stretched) polymer film. Since some polymer films such as amino acid resins have a retardation function without being uniaxially stretched, such a polymer film can also be used as a retardation film.

If desired, a sticking layer such as an adhesive layer or a pressure-sensitive adhesive layer may be provided on one surface of the optical member such as a polarizing plate or a retardation plate obtained in this manner. A peelable sheet may be provided on the adhesive layer.

This optical member is useful as a member for producing a liquid crystal display panel, but it can also be used for optical shutters, light quantity adjusting sheets, goggles, and other uses.

Of these, the liquid crystal display panel is typically
It has a structure of polarizing plate / retarder / liquid crystal cell / polarizing plate.
The retardation plate may be omitted, a composite plate of a polarizing plate and a retardation plate may be used, or a compensating liquid crystal cell may be used instead of the retardation plate.

[0026]

As described above, the protective plate (1) of the present invention comprises the optically isotropic base sheet (11) / metal oxide layer (12) / curable resin cured product layer (13) Isotropic base sheet (11) / curable resin cured product layer (1
3) / Metal oxide layer (12), which is a laminated sheet having any one of the following layer configurations.

The curable resin cured product layer (13) is formed on the optically isotropic base sheet (11) by scratch resistance, surface hardness, moisture permeability resistance,
It contributes to impart properties such as heat resistance and solvent resistance.
The metal oxide layer (12) has an optical isotropic base sheet (11) with scratch resistance, surface hardness, moisture permeation resistance, air permeation resistance, heat resistance,
Contributes to imparting properties such as solvent resistance.

The curable resin cured product layer (13) or the metal oxide layer (12) constituting the outer layer cooperates with the lower metal oxide layer (12) or the curable resin cured product layer (13), It plays a role of further improving scratch resistance and surface hardness. That is, since the curable resin cured product layer (13) or the metal oxide layer (12) is arranged on the lower hard metal oxide layer (12) or curable resin cured product layer (13), It is possible to improve scratch resistance and surface hardness. More specifically, even if only the metal oxide layer (12) or the curable resin cured product layer (13), which is a hard upper layer, is formed on the soft lower layer composed of the optically isotropic base sheet (11), the scratch resistance is improved. No significant improvement in properties and surface hardness can be expected.

In addition, in the case of the above layer structure, since the metal oxide layer (12) is sandwiched between the optically isotropic base sheet (11) and the curable resin cured product layer (13), it is protected. Board
Even if bending force is applied during handling of (1), the metal oxide layer
(12) has the special effect of not causing trouble such as cracking.

[0030]

EXAMPLES The present invention will be further described with reference to examples. Hereinafter, “parts” means parts by weight.

Example 1 FIG. 1 is a sectional view showing an example of a protective plate and an optical member of the present invention.

(11) is a polyarylate film as an example of the optically isotropic base sheet, which is formed by a casting method from a 20 wt% concentration solution of methylene chloride as a solvent. The thickness is 30 μm, the retardation value is 5 nm, and the visible light transmittance is 92%.

(Ac) is an anchor coating layer provided on the optically isotropic base sheet (11), which is coated with a water-soluble quaternized ester urethane anchor coating agent,
It consists of a 1.0 μm thick layer formed by drying.

(13) is a curable resin cured product layer, and from the above anchor coating layer (ac), an epoxy acrylic resin "V-254PA" 10 manufactured by Nippon Steel Chemical Co., Ltd.
An ultraviolet curable resin composition obtained by adding 1 part of benzophenone to 0 part is applied to a thickness of about 5 μm, and 1
It is formed by irradiating ultraviolet rays under the conditions of 20 W / cm, 1 lamp, and 3 seconds.

Reference numeral (12) is a metal oxide layer, which has a thickness of 100 and is formed on the curable resin cured product layer (13) by vapor deposition.
It consists of a layer of 0 Å of SiOx, where x is between 1 and 2. The adhesion of the metal oxide layer (12) to the lower layer is good.

The above layer structure (optical isotropic base sheet (11) /
Anchor coating layer (ac) / curable resin cured product layer (13)
/ The overall retardation value of the protective plate (1) having the metal oxide layer (12) is 5 nm, the visible light transmittance is 87%, and the thickness is 36 μm, and it has optical isotropy.

The optical isotropic base sheet (1
An adhesive was applied to the 1) side and adhesively laminated on both sides of the optical element film (2) to obtain an optical member. In FIG. 1, (ad) is an adhesive layer.

As the optical element film (2), a retardation element film made of a polyvinyl alcohol / iodine type polarizing element film and a uniaxially stretched polyvinyl alcohol film was used. When the optical element film (2) is a polarizing element film, the optical member is a polarizing plate, and when the optical element film (2) is a retardation element film, the optical member is a retardation plate.

Since the outer layers on both surfaces of the optical member thus obtained are formed of the metal oxide layer (12) and the lower layer thereof is the curable resin cured product layer (13), damage resistance, surface Excellent properties such as hardness, moisture resistance, air permeability, heat resistance, solvent resistance, and dust resistance.

Embodiment 2 FIG. 2 is a sectional view showing another example of the protective plate and the optical member of the present invention.

(11) is a polycarbonate film as an example of the optically isotropic base sheet, which is produced by a casting method. The retardation value is 5 nm, the visible light transmittance is 90%, and the thickness is 30 μm.

(12) is a metal oxide layer having a thickness of 10 formed on the above-mentioned optically isotropic base sheet (11) by vapor deposition.
00 Angstrom SiOx (where x is 1 and 2
Between) layers. The adhesion of the metal oxide layer (12) to the optically isotropic base sheet (11) is good.

(13) is a curable resin cured product layer, 40 parts of phenoxy ether resin (manufactured by Tohto Kasei Co., Ltd.), 40 parts of methyl ethyl ketone, 20 parts of cellosolve acetate,
A curable resin composition having a composition of 40 parts of a 75% solution of an adduct of tolylene diisocyanate and trimethylolpropane (Coronate L manufactured by Nippon Polyurethane Industry Co., Ltd.) was applied and dried at 80 ° C. for 4 minutes. And then heated at 130 ℃ for 20 minutes to form a thickness of 10 μm
Layers.

The above layer structure (optical isotropic base sheet (11) /
The overall retardation value of the protective plate (1) having the metal oxide layer (12) / curable resin cured product layer (13)) is 5 nm, the visible light transmittance is 87%, and the thickness is 40 μm. Has isotropic properties.

The optically isotropic base sheet (1
An adhesive was applied to the 1) side and adhesively laminated on both sides of the base film (2) to obtain an optical member. In FIG. 2, (ad) is an adhesive layer.

As the optical element film (2), the same polarizing element film or retardation element film as in Example 1 was used.

Since the outer layers on both surfaces of the optical member thus obtained are formed of the curable resin cured product layer (13) and the lower layer thereof is the metal oxide layer (12), damage resistance, surface Excellent properties such as hardness, moisture resistance, air permeability, heat resistance, solvent resistance, and dust resistance. In addition, the metal oxide layer (1
2) is the optically isotropic base sheet (11) and the curable resin cured product layer (1
Since it is sandwiched with 3), no trouble such as cracking occurs in the metal oxide layer (12) even when a force in the bending direction is applied.

[0048]

The protective plate and the optical member of the present invention include: a curable resin cured product layer (13) or a curable resin cured product layer (13) on the lower hard metal oxide layer (12) or curable resin cured product layer (13); Since the metal oxide layer (12) is arranged, it has excellent scratch resistance and surface hardness, and also has excellent properties such as moisture resistance, air resistance, heat resistance, solvent resistance, and dust resistance.・ The protective plate (1) has a layered structure of optically isotropic base sheet (11) /
When the metal oxide layer (12) / curable resin cured product layer (13) is used, the metal oxide layer (12) includes an optically isotropic base sheet (11) and a curable resin cured product layer (13). Since it is sandwiched between the metal oxide layer (12) and the protective plate (1) or the optical components, even if a force in the bending direction is applied, the metal oxide layer (12) will not be broken. Since the metal oxide layer (12) can be installed at low cost, it does not become a burden in terms of cost.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an example of a protective plate and an optical member of the present invention.

FIG. 2 is a cross-sectional view showing another example of the protective plate and the optical member of the present invention.

[Explanation of symbols]

 (1) ... Protective plate, (11) ... Optical isotropic base sheet, (12) ... Metal oxide layer, (13) ... Curable resin cured material layer, (ac) ... Anchor coating layer, (ad) ... Adhesive layer, (2) ... Optical film

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[Procedure amendment]

[Submission date] December 25, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Claim 2

[Correction method] Change

[Correction content]

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0009

[Correction method] Change

[Correction content]

[0009] The present invention, in this background under scratch resistance, surface hardness, resistance to moisture permeation, resistance permeability, heat resistance, solvent resistance, the optical Motomaku satisfying the required performance such as dust resistance An object of the present invention is to provide a protective plate and optical members such as a polarizing plate and a retardation plate using the protective plate.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tetsunosuke Kobayashi 1-4-16 Nihonbashi-Bakurocho, Chuo-ku, Tokyo Fujimori Industry Co., Ltd.

Claims (3)

[Claims] 1. A protective plate (1) for laminating and adhering to at least one surface of an optical element film (2) comprising a polarizing element film or a retardation element film to protect the optical element film (2). ) Is an optically isotropic base sheet (11) / metal oxide layer (12) / curable resin cured product layer (13), or an optically isotropic base sheet (11) / curable resin cured product layer (13) ) / Metal oxide layer (12), which is a laminated sheet having a layered structure. 2. The metal oxide layer (12) comprises SiOx (provided that
A layer of silicon oxide represented by 1 <x <2).
The surface protection film described. 3. An optical isotropic base sheet (11) side of a protective plate (1) according to claim 1 is laminated and adhered to at least one surface of an optical element film (2) made of a polarizing element film or a retardation element film. Optical member consisting of.