JP2001108981A - Surface protective film, optical member and liquid crystal display - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To satisfy the property that it does not peel off from the antiglare layer or hard coat layer on the optical material surface due to environmental changes such as temperature and humidity, and at the time of peeling, there is no contamination from the antiglare layer or hard coat layer. Of a surface protection film that can be easily peeled off. SOLUTION: An antiglare layer or a hard coat layer (2) is formed on the surface.
A protective film (1) for adhesively covering the surface of an optical material (2) provided with 1) through an adhesive layer (12), wherein the adhesive layer and the above-mentioned antiglare layer or hard coat layer are the same additive And a surface protective film in which the additive reduces the adhesive strength of the pressure-sensitive adhesive layer, and an optical material obtained by adhesively coating an antiglare layer or a hard coat layer on the surface of an optical material with the surface protective film. A liquid crystal display device comprising a member and its optical member on at least one side of a liquid crystal cell. [Effect] It is possible to form an easily peelable pressure-sensitive adhesive layer whose adhesive strength is hard to increase with time, and it can be peeled without damaging the liquid crystal cell and without surface contamination of the optical material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface protective film which can be easily peeled off from an optical member adhered to a liquid crystal cell.

[0002]

BACKGROUND OF THE INVENTION An optical material such as a polarizing plate used for forming a liquid crystal display device or an elliptically polarizing plate obtained by laminating a retardation plate with the polarizing plate is provided with an antiglare layer or a hard coat for the purpose of improving the visibility and abrasion resistance. After the layer is provided, it is subjected to an assembly process of bonding to a liquid crystal cell as an optical member in a state where it is adhered and covered with a surface protection film so that the surface is not damaged or contaminated, so that surface protection is unnecessary As a result, the surface protective film is peeled off from the optical member.

However, the conventional surface protective film has a large adhesive force when peeled off from the antiglare layer or the hard coat layer on the surface of the optical material after assembling due to the enlargement of the liquid crystal display device and the like, resulting in an increase in work efficiency. There is a problem that the cell gap is changed due to the peeling, the display quality is reduced, and the display device is damaged.

[0004]

SUMMARY OF THE INVENTION The present invention is intended to satisfy the property of not peeling off from an antiglare layer or a hard coat layer on the surface of an optical material due to environmental changes such as temperature and humidity, and at the time of peeling, from the antiglare layer or the hard coat layer. An object of the present invention is to develop a surface protective film that can be easily peeled off without contamination.

[0005]

According to the present invention, there is provided a protective film for adhesively covering the surface of an optical material having an antiglare layer or a hard coat layer on the surface thereof through an adhesive layer. The hard coat layer contains the same additive, and the additive protects the surface of the optical material with the surface protective film, wherein the additive reduces the adhesive strength of the adhesive layer. It is an object of the present invention to provide an optical member characterized in that an antiglare layer or a hard coat layer is adhesively coated, and a liquid crystal display device having the optical member on at least one side of a liquid crystal cell.

[0006]

According to the present invention, it is possible to form an easily peelable pressure-sensitive adhesive layer whose adhesive strength is hardly increased with time by containing the above-mentioned additive,
Satisfies the property that it does not peel off from the antiglare layer or hard coat layer on the optical material surface due to environmental changes such as temperature and humidity, and even after continuing the adhesive state for a long period of time, hands and machinery from the optical member adhered to the liquid crystal cell And a surface protection film that can be easily peeled off without giving damage such as a change in the cell gap to the liquid crystal cell.

In addition, by including the above-mentioned additive also in the antiglare layer or the hard coat layer, it is possible to prevent the additive from remaining as a contaminant in the antiglare layer or the hard coat layer on the surface of the optical material after the surface protective film is peeled off. It is possible to prevent the deterioration of the display quality of the liquid crystal display device due to the contamination. In the method of reducing the adhesive strength by adding a unique surfactant etc. to the adhesive, the surfactant etc. migrates to the optical material surface and contaminates the optical material surface when the surface protection film is peeled off, The display quality of the liquid crystal display device is reduced.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The surface protective film according to the present invention comprises:
A protective film that adhesively covers the surface of an optical material provided with an antiglare layer or a hard coat layer via an adhesive layer,
The pressure-sensitive adhesive layer and the antiglare layer or the hard coat layer contain the same additive, and the additive reduces the adhesive force of the pressure-sensitive adhesive layer. It consists of an antiglare layer or a hard coat layer on the surface of the optical material which is adhesively coated via the adhesive layer. FIG. 1 shows an example of the optical member. 1 is a surface protection film,
11 is a protective substrate, 12 is an adhesive layer, 2 is an optical material, and 21 is an antiglare layer or a hard coat layer. Also 22
Is an adhesive layer.

The surface protective film is formed such that an adhesive layer 12 is provided on a protective substrate 11 as shown in the figure and the protective substrate can be peeled together with the adhesive layer from an antiglare layer or a hard coat layer on the optical material surface. . As the protective base material, an appropriate thin leaf body according to the related art can be used, and there is no particular limitation. Generally, from the point of viewability and controllability of the optical material by transparency, for example, polyester resin or acetate resin, polyether sulfone resin or polycarbonate resin,
A protective substrate made of a film or rubber sheet made of a transparent polymer such as a polyamide resin, a polyimide resin, a polyolefin resin or an acrylic resin, or a laminate thereof is used.

[0010] The thickness of the protective substrate can be appropriately determined according to the strength and the like, and is generally 500 µm or less, especially 5 to 300 µm.
m, especially 10 to 200 μm. An antistatic layer may be provided on one or both sides of the protective substrate for the purpose of preventing static charge during peeling. The surface of the protective substrate on which the adhesive layer is provided is subjected to an appropriate surface treatment such as a corona treatment, an ultraviolet irradiation treatment, a plasma treatment, a sputter etching treatment, and an undercoat treatment for the purpose of improving the adhesion to the adhesion layer. You can also.

The surface protective film can be formed by attaching an adhesive layer to a protective substrate, and the attachment can be performed by an appropriate method. Incidentally, as an example, for example, a base polymer or the like is dissolved or dispersed in a suitable solvent to prepare a pressure-sensitive adhesive liquid, which is directly applied on a protective substrate by a suitable development method such as a casting method or a coating method. Or a method in which an adhesive layer is formed on a separator and transferred to a protective substrate according to the method described above.

In forming the above-mentioned pressure-sensitive adhesive layer, an appropriate pressure-sensitive adhesive or pressure-sensitive adhesive can be used, and the type thereof is not particularly limited. Incidentally, examples thereof include those having an appropriate polymer such as an acrylic polymer, a silicone polymer, a polyester or a polyurethane, a polyamide or a polyether, a fluorine or a rubber as a base polymer, and the like.

In preparing the above-mentioned pressure-sensitive adhesive liquid, an additive capable of lowering the adhesive strength of the pressure-sensitive adhesive layer is added, whereby the object of the present invention described above is achieved. As the above-mentioned additives, those which do not hinder their functions are used because they are also added to the antiglare layer or the hard coat layer which forms the surface layer of the optical material.

Examples of the above-mentioned additives include perfluoroalkyl sulfonates and perfluoroalkyl carboxylate, perfluoroalkyl group-containing oligomers, fluoroolefin / vinyl ether polymers, and perfluoroalkyl acrylate polymers such as perfluoroalkyl acrylate polymers. Examples thereof include compounds having a surface activity such as a series compound, a phosphoric acid ester or a salt thereof, an alkyl ether sulfate or a salt thereof, a polyoxyethylene alkyl ether, sodium laurate, and lauryl betaine.

One or more of the above-mentioned additives can be used, and the amount of the additives can be appropriately determined according to the desired adhesive strength and the like. In the present invention, the adhesive strength of the optical material surface to the antiglare layer or the hard coat layer is set to 100 gf / 10 mm based on a 180 degree peel at room temperature.
Hereinafter, especially 10 to 80 gf / 10 mm, especially 20 to 70 gf / 10
The pressure-sensitive adhesive layer is preferably adjusted to mm, and from this point, it is preferable to add the additive in an amount of 15 parts by weight or less, especially 10 parts by weight or less, particularly 1 to 8 parts by weight, per 100 parts by weight of the base polymer.

If necessary, the adhesive layer may be mixed with appropriate additives such as natural or synthetic resins such as tackifying resins and antioxidants for the purpose of controlling the adhesive strength and the like. Can also. The adhesive layer can also be provided on the protective substrate as a superimposed layer of different compositions or types. The thickness of the pressure-sensitive adhesive layer can be appropriately determined according to the adhesive strength and the surface roughness of the antiglare layer or the hard coat layer, and is generally 1 to 50.
0 μm, especially 5 to 200 μm, especially 10 to 100 μm.

Optical materials in which an antiglare layer or a hard coat layer is provided on the surface of an object to be coated with an adhesive with a surface protective film include, for example, a polarizing plate, a reflective polarizing plate, a semi-transmissive polarizing plate, and a polarized light separating polarizing plate. An elliptically polarizing plate, a reflective elliptically polarizing plate, or a transflective elliptically polarizing plate formed by combining a retardation plate may be used as appropriate for forming a liquid crystal display device or the like,
There is no particular limitation on the type.

Incidentally, specific examples of the above-mentioned polarizing plate include iodine and / or iodine on a hydrophilic polymer film such as a polyvinyl alcohol-based film, a partially formalized polyvinyl alcohol-based film, and an ethylene / vinyl acetate copolymer-based partially saponified film. Examples thereof include a film obtained by adsorbing a dichroic dye and stretching, a polarizing film made of a polyene oriented film such as a dehydrated product of polyvinyl alcohol and a dehydrochlorinated product of polyvinyl chloride. The polarizing plate may have a transparent protective layer on one or both sides of a polarizing film.

On the other hand, the above-mentioned reflective polarizing plate is provided with a reflecting layer on the polarizing plate, and is used for forming a liquid crystal display device of a type that reflects incident light from the viewing side (display side) to display. This has the advantage that the built-in light source such as a backlight can be omitted and the thickness of the liquid crystal display device can be easily reduced. The reflective polarizing plate can be formed by an appropriate method such as a method in which a reflective layer made of metal or the like is provided on one surface of the polarizing plate via a transparent protective layer or the like as necessary.

Specific examples of the reflective polarizing plate include a transparent protective layer that has been matted as required, and a reflective layer formed by attaching a foil or a vapor-deposited film made of a reflective metal such as aluminum to one surface of the transparent protective layer. can give. Further, there may be mentioned, for example, those in which fine particles are contained in the transparent protective layer to form a fine surface uneven structure, and a reflective layer having a fine uneven structure is provided thereon. The reflective layer has a reflective surface covered with a transparent protective layer or a polarizing plate. Is more preferable.

The reflective layer having the above-mentioned fine uneven structure has an advantage that the incident light is diffused by irregular reflection to prevent directivity and glare, and that unevenness in brightness can be suppressed.
Further, the transparent protective layer containing fine particles also has an advantage that the incident light and the reflected light thereof are diffused when transmitting the light and the unevenness of light and darkness can be further suppressed.

The reflection layer having a fine uneven structure reflecting the fine uneven structure on the surface of the transparent protective layer is formed by an appropriate method such as an evaporation method such as a vacuum evaporation method, an ion plating method and a sputtering method, and a plating method. The method can be performed by directly attaching a metal to the surface of the transparent protective layer. The transflective polarizing plate can be obtained by forming the reflective layer as a transflective reflective layer such as a half mirror that reflects and transmits light.

For the formation of the transparent protective layer in the above-mentioned polarizing plate, a polymer or the like having excellent transparency, mechanical strength, heat stability, moisture shielding property and the like is preferably used. Examples thereof include polyester resins, acetate resins, arylate resins and sulfone resins, polyethersulfone resins and polycarbonate resins, polyamide resins and polyimide resins, polyolefin resins and acrylic resins, and styrene resins. Examples of the resin include a thermosetting resin such as an acrylic resin, a urethane resin, an acrylic urethane resin, an epoxy resin, and a silicone resin, or an ultraviolet curing resin.

The transparent protective layer may be formed by an appropriate method such as a method of applying a polymer or a method of laminating a film, and the thickness may be appropriately determined. Generally 500 μm
Hereinafter, the thickness is preferably 1 to 300 μm, particularly 5 to 200 μm. The fine particles to be contained in the formation of the transparent protective layer having the fine surface irregularity structure include, for example, an average particle size of 0.5 to 5
Transparent inorganic fine particles of 0 μm silica, alumina, titania, zirconia, tin oxide, indium oxide, cadmium oxide, antimony oxide, and the like, and organic fine particles of a crosslinked or uncrosslinked polymer, etc. Fine particles are used. The amount of fine particles used is 1
The amount is generally 2 to 50 parts by weight, preferably 5 to 25 parts by weight per 00 parts by weight, but is not limited thereto.

In addition, the above-mentioned polarized light separating type polarizing plate reflects a linearly polarized light having a predetermined polarization axis or a circularly polarized light having a predetermined direction when natural light is incident thereon, and a brightness enhancement plate showing a characteristic of transmitting other light to the polarizing plate. Light from a light source such as a backlight is incident to obtain transmitted light in a predetermined polarization state, and reflected light is inverted through a reflective layer or the like to be re-incident on a brightness enhancement plate. Alternatively, by increasing the amount of light transmitted through the brightness enhancement plate by transmitting the whole as light of a predetermined polarization state, and by increasing the amount of light that can be used for a liquid crystal display or the like by supplying polarized light that is hardly absorbed by the polarizing plate. The brightness can be improved.

As the brightness enhancing plate in the above-mentioned polarized light separating type polarizing plate, for example, a linearly polarized light having a predetermined polarization axis such as a multilayer thin film of a dielectric or a multilayer laminate of thin films having different refractive index anisotropy is transmitted. Other light, such as those exhibiting the property of reflecting other light, such as cholesteric liquid crystal layers, especially cholesteric liquid crystal polymer oriented films and those in which the oriented liquid crystal layer is supported on a film substrate, and which reflects left or right circularly polarized light. Any suitable light such as a light-transmitting light may be used.

Therefore, in the above-described brightness improving plate of a type that transmits linearly polarized light having a predetermined polarization axis, the transmitted light is directly incident on the polarizing plate with the polarization axis aligned, thereby efficiently absorbing the polarizing plate while suppressing absorption loss. Can be transmitted. On the other hand, a brightness enhancement plate that transmits circularly polarized light, such as a cholesteric liquid crystal layer, can be directly incident on the polarizing plate.However, from the viewpoint of suppressing absorption loss, the transmitted circularly polarized light is converted to linearly polarized light through a retardation plate. It is preferable to make the light incident on the polarizing plate. Incidentally, by using a quarter-wave plate as the retardation plate, circularly polarized light can be converted into linearly polarized light.

A retardation plate that functions as a quarter-wave plate in a wide wavelength range such as a visible light region is, for example, a retardation layer that functions as a quarter-wave plate with respect to monochromatic light such as light having a wavelength of 550 nm. , For example, a method of superimposing a retardation layer functioning as a half-wave plate with the retardation layer exhibiting the above retardation characteristic. Therefore, the retardation plate disposed between the polarizing plate and the brightness enhancement plate may be composed of one or more retardation layers.

The cholesteric liquid crystal layer also has a structure in which two or three or more cholesteric liquid crystal layers are superimposed in a combination of those having different reflection wavelengths, so that a layer which reflects circularly polarized light in a wide wavelength range such as a visible light region can be obtained. Thus, it is possible to obtain circularly polarized light transmitted in a wide wavelength range.

The optical material may be formed by laminating two or three or more optical layers, such as a laminate of the above-mentioned elliptically polarizing plate, reflection type polarizing plate and retardation plate. Therefore, a reflective elliptically polarizing plate, a transflective elliptically polarizing plate, or a combination of a reflective polarizing plate, a transflective polarizing plate, and a retardation plate may be used. An optical material in which two or three or more optical layers are laminated,
Although it can be formed by a method of laminating layers sequentially in the manufacturing process of a liquid crystal display device or the like, a material that is preliminarily laminated as an optical material is excellent in stability of quality and workability in assembling, etc. There is an advantage that the manufacturing efficiency of the device or the like can be improved. For the lamination, an appropriate adhesive means such as an adhesive layer can be used.

As a specific example of the above-mentioned retardation plate, a multilayer film obtained by stretching a film made of an appropriate polymer such as polycarbonate, polyvinyl alcohol, polystyrene, polymethyl methacrylate, polypropylene, other polyolefin, polyarylate or polyamide is used. Examples thereof include a refractive film, an alignment film of a liquid crystal polymer, and an alignment layer of a liquid crystal polymer supported by a film.

The retardation plate is used for various wavelength plates such as 1/2 or 1/4, for example, for compensating coloring due to birefringence of a liquid crystal layer and compensating for a viewing angle such as expansion of a viewing angle. The film may be of any purpose having an appropriate retardation, and may be an obliquely oriented film having a controlled refractive index in the thickness direction. Further, two or more retardation plates may be laminated to control optical characteristics such as retardation.

The above-mentioned obliquely oriented film can be formed, for example, by applying a heat-shrinkable film to a polymer film and applying a shrinkage force by heating to stretch or / and shrink the polymer film. It can be obtained by a method such as

As described above, the optical material to be coated with the surface protection film is provided with an antiglare layer or a hard coat layer on the surface, and the antiglare layer scatters external light reflected on the surface. This is performed for the purpose of preventing the surface reflected light from causing glare or the like and impairing the visibility of the light transmitted through the optical member. The hard coat layer is provided for the purpose of improving scratch resistance such as prevention of scratches on the surface of the optical material.

The antiglare layer and the hard coat layer are not particularly limited except that they can be formed as appropriate having the above-mentioned functions and contain at least one of the above-mentioned additives common to the adhesive layer. Incidentally, the anti-glare layer is formed by giving a fine uneven structure of light scattering reflection by an appropriate method such as a roughening method such as a sand blast method or an embossing method, or a resin coating method containing transparent particles. Can be. Therefore, the anti-glare layer can be provided on the surface of the optical material in an appropriate form such as a coating layer or an adhesive layer of an anti-glare sheet according to the above-mentioned transparent protective layer having a fine surface irregularity structure.

On the other hand, the hard coat layer is also coated with an appropriate resin capable of forming a hard film, such as a resin which is cured by heat or ultraviolet rays, such as an acrylic, urethane, acrylic urethane, epoxy, or silicone resin. It can be formed as a working layer or the like.

The content of the additive in common with the pressure-sensitive adhesive layer in the antiglare layer and the hard coat layer can be appropriately determined within a range not to impair its function.
-10% by weight, especially 0.1-5% by weight, especially 0.2-3%
% By weight.

The optical member according to the present invention has an antiglare layer or a hard coat layer 21 provided on the surface of the optical material 2 as shown in FIG. Adhesive coating with surface protection film
Either one or both of the front and back surfaces of the optical material may be used. When a surface protective film is provided only on one side of the optical material as shown in the figure, an adhesive layer 22 for adhering to another member such as a liquid crystal cell can be provided on the other side, if necessary.

The above-mentioned pressure-sensitive adhesive layer can be formed with an appropriate pressure-sensitive adhesive according to the related art. Above all, from the viewpoint of preventing foaming and peeling phenomena due to moisture absorption, deterioration of optical characteristics due to difference in thermal expansion, prevention of liquid crystal cell warpage, and formation of a high quality and durable liquid crystal display device, the moisture absorption rate It is preferable that the pressure-sensitive adhesive layer has low heat resistance and excellent heat resistance. In addition, an adhesive layer or the like which contains fine particles and exhibits light diffusibility can be used.

When the adhesive layer provided on the optical material is exposed on the surface, the adhesive layer may be temporarily covered with the separator 3 as shown in FIG. preferable. The separator is formed by, for example, providing a release coating with a suitable release agent such as a silicone-based or long-chain alkyl-based, fluorine-based or molybdenum sulfide on a suitable thin leaf according to the above-described protective substrate or the like. It can be carried out.

Each layer in the optical material, the antiglare layer, the hard coat layer, the adhesive layer and the like forming the above optical member is
For example, those having an ultraviolet absorbing ability by an appropriate method such as a method of treating with a UV absorber such as a salicylic acid ester compound, a benzophenol compound, a benzotriazole compound, a cyanoacrylate compound, a nickel complex salt compound, etc. You may.

The surface protective film according to the present invention is bonded to an antiglare layer or a hard coat layer on the surface of an optical material to form an optical member, which is bonded to another member such as a liquid crystal cell, and if necessary, the bonded state. Is preferably used for forming various devices such as a liquid crystal display device that needs to be separated from the antiglare layer or the hard coat layer of the optical member after the surface protection film is subjected to a heat treatment such as aging in order to stabilize the film. Can be.

The above-mentioned liquid crystal display device has an appropriate structure according to the prior art, such as a transmission type or reflection type, or a transmission / reflection type in which the optical member according to the present invention is arranged on one side or both sides of a liquid crystal cell. It can be formed as one. Therefore, the liquid crystal cell forming the liquid crystal display device is arbitrary, and may be an appropriate type such as an active matrix driving type represented by a thin film transistor type, a simple matrix driving type represented by a twisted nematic type or a super twisted nematic type, and the like. A liquid crystal cell of a type may be used.

When optical members are provided on both sides of the liquid crystal cell, they may be the same or different. Further, in forming a liquid crystal display device,
For example, one or more layers of appropriate components such as a prism array sheet, a lens array sheet, a light diffusing plate, and a backlight can be arranged at appropriate positions.

[0045]

EXAMPLES Example 1 100 parts of isononyl acrylate (parts by weight, the same applies hereinafter) and 4 parts of 2-hydroxyethyl acrylate were added to 150 parts of ethyl acetate via 0.5 part of azobisisobutyronitrile.
The acrylic polymer solution obtained by reacting at about 60 ° C. for 8 hours was added with 3 parts of a fluorine-based surfactant and 3 parts of an isocyanate-based cross-linking agent per 100 parts of the solid content to form a pressure-sensitive adhesive syrup. After coating on a 38 μm polyester film and drying to form a 25 μm thick acrylic pressure-sensitive adhesive layer and obtaining a surface protection film, it is adhered to an antiglare layer provided on the surface of a polarizing plate to form an optical member. I got

The above-mentioned polarizing plate is prepared by subjecting 100 parts of an ultraviolet-curable acrylic urethane oligomer, 8 parts of silica particles, 3 parts of benzophenone and 0.5 part of a fluorine-based surfactant added to the adhesive layer to high-speed through ethyl acetate. An antiglare film formed by applying a mixed dispersion having a solid content of 50% by weight obtained by stirring on one surface of a triacetyl cellulose film having a thickness of 80 μm and drying and then curing with a high-pressure mercury lamp is used. A polarizing film obtained by stretching 5 times in an aqueous solution is adhered to one surface of the polarizing film via an adhesive layer, and a triacetyl cellulose film having a thickness of 80 μm is adhered to the other surface of the polarizing film via the adhesive layer. It is obtained by attaching an acrylic pressure-sensitive adhesive layer protected by a separator.

Example 2 A polarizing plate was obtained in the same manner as in Example 1 except that a hard coat layer having no silica particles was provided on a triacetyl cellulose film in place of the antiglare layer, and a polarizing plate was obtained. The optical member was obtained by bonding.

Comparative Example 1 A pressure-sensitive adhesive syrup containing no fluorinated surfactant was obtained, and a surface protective film and an optical member were obtained using the same according to Example 1.

Comparative Example 2 A pressure-sensitive adhesive syrup containing no fluorine-based surfactant was obtained, and a surface protective film and an optical member were obtained according to Example 2 using the same.

Comparative Example 3 A pressure-sensitive adhesive syrup to which a long-chain alkyl-based polymer was added in place of the fluorine-based surfactant was obtained, and a surface protective film and an optical member were obtained according to Example 1 using the syrup.

Comparative Example 4 A pressure-sensitive adhesive syrup to which a long-chain alkyl-based polymer was added in place of the fluorine-based surfactant was obtained, and a surface protective film and an optical member were obtained in the same manner as in Example 2.

Evaluation Test Adhesive Strength The optical members obtained in the examples and comparative examples were cut into a test piece having a width of 10 mm, and the adhesive strength of the surface protective film was examined by a manual peeling operation using a spring balance. The adhesive strength is
Ten workers performed the peeling operation five times each, and the average value of each worker was obtained.

Peeling workability The optical member obtained in each of the examples and comparative examples is 300 mm long and 20 mm wide.
A test piece cut to a size of 0 mm was adhered to a glass plate via an adhesive layer provided on the polarizing plate, the glass plate was placed on a table with the lower side, and an adhesive tape was adhered to a corner of the surface protective film. Then, the peeling operation was performed by a pickup method via the tape, and the peeling workability in that case was examined. Evaluation,
The case where the adhesive force was strong and time was required for peeling, the case where the glass plate itself was lifted at the time of peeling, and the case where the glass plate itself could be smoothly peeled without lifting were evaluated as good.

Contamination The antiglare surface or the hard coat surface after peeling by the peeling workability test was visually observed to check for the presence or absence of contamination.

The above results are shown in the following table. Adhesive force (gf / 10mm) Peeling workability Contamination example 1 30-60 Good No No Example 2 20-50 Good Good None Comparative example 1 140-160 Poor (* 1) None Comparative example 2 120-150 Poor (* 1) None Comparative Example 3 70 to 100 Good Yes Comparative Example 4 60 to 80 Good Yes * 1: Difficult to peel without supporting the glass plate

From the table, it can be seen from the table that the surface protective film can be peeled off from the antiglare layer or the hard coat layer on the surface of the optical material adhered to the glass plate with good workability and without giving the liquid crystal cell damage such as a change in the cell gap. It can be seen that the antiglare layer or the hard coat layer after peeling is not contaminated.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an optical member.

[Explanation of symbols]

 1: Surface protective film 11: Protective substrate 12: Adhesive layer 2: Optical material 21: Antiglare layer or hard coat layer 22: Adhesive layer 3: Separator

Continuation of the front page (72) Inventor Ning Takahashi 1-1-2 Shimohozumi, Ibaraki-shi, Osaka Nitto Denko Corporation (72) Inventor Toshimori Masada 1-2-1, Shimohozumi, Ibaraki-shi, Osaka F-term in TEPCO (reference) 2H091 FA08X FA11X FA16Z FA37X FB02 FB08 FC02 FC03 FD06 FD14 GA16 HA07 HA10 LA02 LA19 2K009 AA00 BB24 CC24 CC47 DD02 DD06 EE00 4F100 AK25G AK41B AT00A AT00B AT00B AT00B CA00B AT00B AT00B AT00B JK12A JL06 JL13G JL14B JN06A

Claims (4)

[Claims] 1. A protective film for adhesively coating the surface of an optical material provided with an antiglare layer or a hard coat layer on the surface thereof via an adhesive layer, wherein the adhesive layer and the antiglare layer or the hard coat layer are A surface protective film containing the same additive, wherein the additive reduces the adhesive strength of the pressure-sensitive adhesive layer. 2. An optical member comprising the surface protective film according to claim 1, wherein an antiglare layer or a hard coat layer on the surface of the optical material is adhesively coated via the adhesive layer. 3. The method according to claim 2, wherein the optical material is a polarizing plate,
An optical member which is a reflective polarizing plate, a transflective polarizing plate, a polarized light separating polarizing plate, or a laminate having a retardation plate thereof. 4. A liquid crystal display device comprising the optical member according to claim 2 on at least one side of a liquid crystal cell.