JP2000321423A - Optical member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an optical member which hardly gives rise to the glue chipping, glue contamination, etc., of a tacky adhesive layer side surface and hardly gives rise to optical abnormality even when the optical member is subjected to transportation, assembly work, etc. SOLUTION: This optical member has a protective film 1 on one surface of an optical blank 2 and a separator 3 via the tacky adhesive layer 21 on the other surface. The protective film 1 and the separator 3 have surface coatings 11 and 31 having a surface tension below 20 dyn/cm on the outside surfaces. As a result, the surface coatings coated on the front and the rear suppress the adhesion of the tacky adhesive layers and prevent the occurrence of the glue chipping and glue contamination even if rubbing against each other occurs when the optical members are stacked on each other and are subjected to the transportation etc.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical member in which chipping or dirt on the side of an adhesive layer provided on an optical material is prevented.

[0002]

BACKGROUND OF THE INVENTION Optical materials such as a polarizing plate and a retardation plate used for forming a liquid crystal display (LCD) and the like are, for example, in the position of a polarizing plate for the purpose of preventing quality variation and increasing the efficiency of LCD assembly and the like. An adhesive layer is provided in advance on an optical material, such as an elliptically polarizing plate in which a retardation plate is laminated in advance via an adhesive layer, or an optical member in which an adhesive layer for bonding a polarizing plate to another member such as a liquid crystal cell is provided in advance. It is practically used as a laminated body.

[0003] However, when the optical member made of the laminate is used for transportation or assembly work, there is a problem that glue chips or glue contamination on the side surface of the adhesive layer occurs. Such glue chipping or glue contamination becomes an optical abnormal point such as a refractive index abnormality when an optical material is applied to an LCD, and an abnormal phenomenon due to the abnormal point is enlarged due to a diffraction effect or a scattering effect, so that the optical member is easily noticeable. Is difficult.

[0004]

An object of the present invention is to develop an optical member which is less likely to cause chipping or glue contamination on the side surface of an adhesive layer even when subjected to transportation or assembly work, and which is unlikely to cause optical abnormalities.

[0005]

According to the present invention, an optical material has a protective film on one surface and a separator on the other surface via an adhesive layer, and the protective film and the separator have an outer surface having a surface tension of 20 dyn / cm or less. An optical member having a coat is provided.

[0006]

According to the present invention, even when rubbing occurs when optical members are stacked and transported, the surface coats provided on the front and back surfaces suppress the adhesion of the adhesive layer, thereby preventing chipping or glue contamination. It is possible to prevent the occurrence of an optical abnormality.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The optical member according to the present invention comprises a protective film on one side of an optical material and a separator on the other side via an adhesive layer, and the protective film and the separator have a surface tension of 20 dyn / cm on the outer surface. It has the following surface coat. An example is shown in FIG. 1 is a protective film, 2 is an optical member, 3 is a separator, and 11, 31
Is a surface coat, and 12 and 21 are adhesive layers.

The optical material may be any suitable material used for forming a liquid crystal display device such as a polarizing plate, a retardation plate, and an elliptically polarizing plate obtained by laminating them, and the type is not particularly limited. Therefore, the polarizing plate may be a reflection type or the like. Also, the retardation plate may have an appropriate purpose, such as a half-wave plate or a quarter-wave plate or viewing angle compensation. In the case of a laminated type optical material such as the above-mentioned elliptically polarizing plate, the lamination may be performed through an appropriate bonding means such as an adhesive layer.

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 reflection type polarizing plate is provided with a reflection layer on the polarizing plate, and is used for forming a liquid crystal display device or the like of a type that reflects incident light from the viewing side (display side) to display. In addition, there is an advantage that a 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 which is matted if necessary, 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 is used in a state where the reflective surface is covered with a transparent protective layer, a polarizing plate, or the like, in order to prevent a decrease in reflectance due to oxidation, and to maintain the initial reflectance for a long period of time, and to separately provide a protective layer. Is more preferable.

The reflective layer having the above-described fine uneven structure has an advantage that the incident light is diffused by irregular reflection to prevent directivity and glaring appearance, 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.

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 and moisture shielding properties is preferably used. Examples of such resins include polyester resins and acetate resins, polyethersulfone resins and polycarbonate resins,
Examples of the resin include a polyamide resin, a polyimide resin, a polyolefin resin, an acrylic resin, and a thermosetting resin such as an acrylic resin, a urethane resin, an acrylic urethane resin, an epoxy resin, or a silicone resin, or an ultraviolet curable 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
It is common to use 2 to 50 parts by weight, especially 5 to 25 parts by weight, per 100 parts by weight.

On the other hand, as a specific example of the above retardation plate, a film made of an appropriate polymer such as polycarbonate, polyvinyl alcohol, polystyrene, polymethyl methacrylate, polypropylene, other polyolefin, polyarylate, or polyamide is stretched. Birefringent film or liquid crystal polymer oriented film,
Examples thereof include a film in which an alignment layer of a liquid crystal polymer is supported by a film.

The retardation plate may have an appropriate retardation in accordance with the intended use, for example, various wavelength plates or those for the purpose of compensating the viewing angle or the like by coloring the birefringence of the liquid crystal layer. A structure in which optical characteristics such as retardation are controlled by laminating more than two kinds of retardation plates may be used.

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 combination of a reflective polarizing plate and a retardation plate or a combination of a polarizing plate and a compensating retardation plate may be used.

The optical material in which two or three or more optical layers are laminated can also be formed by a method in which the optical materials are laminated separately in the manufacturing process of a liquid crystal display device or the like. The method described above has an advantage in that it is excellent in quality stability, assembling workability, and the like, and can improve manufacturing efficiency of a liquid crystal display device and the like.

The optical member according to the present invention has a structure in which one surface of an optical material 2 is covered with a protective film 1 and an adhesive layer 21 provided on the other surface of the optical material is temporarily attached with a separator 3 as shown in FIG. is there. The protective film is usually adhered to the optical material 2 via the adhesive layer 12 as shown in the figure, and the adhesive layer 1
2 is formed so as to be peelable from the optical material together with the protective film 1. On the other hand, the separator 3 is formed so that it can be peeled off at the interface with the adhesive layer 21 to which the separator 3 adheres.

Therefore, in the case of a protective film, the surface of the optical material is usually exposed by peeling, and in the case of a separator, the adhesive layer remains on the optical member by peeling, and the adhesive layer is separated from other parts such as a liquid crystal cell. It can be used for bonding with members.
Note that the protective film may also have an adhesive layer to which it adheres, such as a separator, remaining on the optical material.

For forming the adhesive layer provided on the protective film or the adhesive layer remaining on the optical material, an appropriate adhesive substance or adhesive can be used, and there is no particular limitation. Incidentally, examples thereof include those using 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. Above all,
For the formation of the adhesive layer to be left on the optical material, it has excellent optical transparency like acrylic adhesive, shows moderate wettability, cohesiveness and adhesive adhesive properties, and has excellent weather resistance and heat resistance Those can be preferably used.

In addition to the above, the adhesive layer remaining on the optical material prevents foaming and peeling phenomena due to moisture absorption, prevents deterioration of optical characteristics due to a difference in thermal expansion, prevents warpage of the liquid crystal cell, and provides high quality and durability. From the viewpoint of excellent formability of a liquid crystal display device, it is preferable that the liquid crystal display device is formed of a material having a low moisture absorption rate and excellent heat resistance.

The adhesive layer is made of, for example, natural or synthetic resins, especially, tackifier resins, fillers, pigments, coloring agents, oxidizing agents, and the like comprising glass fibers, glass beads, metal powders, and other inorganic powders. It may contain an appropriate additive such as an inhibitor which may be added to the adhesive layer. The adhesive layer remaining on the optical material may be one containing fine particles and exhibiting light diffusivity.

The attachment of the adhesive layer to the protective film or the optical material can be performed by an appropriate method. Incidentally, as an example, an adhesive substance or a composition thereof is dissolved or dispersed in a solvent composed of an appropriate solvent alone or a mixture such as toluene or ethyl acetate to prepare an adhesive liquid of about 10 to 40% by weight. Then, it is directly applied on a protective film or an optical material by an appropriate developing method such as a casting method or a coating method, or an adhesive layer is formed on a separator according to the above, and the protective film or an optical material is formed. There is a method of transferring onto a material.

The pressure-sensitive adhesive layer may be provided on the protective film or the optical member as a superposed layer of different compositions or types. The thickness of the pressure-sensitive adhesive layer can be appropriately determined depending on the purpose of use and adhesive strength, etc., and is generally 1 to 500 μm, preferably 5 to 500 μm.
It is 200 μm, especially 10 to 100 μm. The adhesive layer provided on the protective film or the optical member may have the same composition or type, or may have a different composition.

The film base material for forming the protective film may be, for example, an appropriate thin leaf according to the prior art such as a plastic film or rubber sheet, paper or cloth, nonwoven fabric or net, foamed sheet or metal foil, or a laminate thereof. Can be used. The thickness of the film substrate can be appropriately determined according to the strength and the like, and is generally 500 μm or less, preferably 5 to 300 μm.
μm, especially 10 to 200 μm.

On the other hand, the purpose of the separator for temporarily covering the adhesive layer surface is to prevent contamination of the adhesive layer until the adhesive layer is put to practical use. The separator is formed by, for example, providing a release coat 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 protective film described above. Can be.

The optical member according to the present invention has a surface coat 11 on the outer surfaces of the protective film 1 and the separator 3 as shown in FIG.
31 are provided. Such a surface coat is provided for the purpose of preventing the adhesive layer from adhering and causing chipping or glue contamination when the optical members are stored or transported as described above.

It is necessary that the surface coat has a surface tension lower than that of the adhesive layer provided on the optical material in order to achieve the above object. In the present invention, the surface coat is 20 dyn / cm.
It is formed as having the following surface tension. In forming the surface coat, an appropriate substance that satisfies the surface tension state can be used, but generally, the above-described release agent for forming a release coat is used.

Each layer such as a polarizing plate, a retardation plate, a transparent protective layer and an adhesive layer forming the above-mentioned optical material is made of, for example, a salicylate compound, a benzophenol compound, a benzotriazole compound, a cyanoacrylate compound, or the like. It may have an ultraviolet absorbing ability by an appropriate method such as a method of treating with an ultraviolet absorbent such as a nickel complex compound.

The optical member according to the present invention can be preferably used for forming various devices such as a liquid crystal display device.

[0033]

EXAMPLE 1 A transparent protective layer made of a triacetyl cellulose film was adhered to both sides of a polyvinyl alcohol-based polarizing film via a polyvinyl alcohol-based adhesive layer to a thickness of 180 μm.
A protective film comprising a 50 μm-thick PET film having a surface coated with a long-chain alkyl-based release agent on one surface of a polarizing plate, and a 20 μm-thick acrylic pressure-sensitive adhesive layer provided on the back surface, with the adhesive layer interposed therebetween. To the other side of the polarizing plate,
A 20 μm-thick acrylic pressure-sensitive adhesive layer is provided on the back surface of a 38 μm-thick PET film separator with its surface coated with a long-chain alkyl-based release agent via a silicone-based release coat, which is adhered together with the separator. An optical member was obtained.

Comparative Example An optical member was obtained in the same manner as in Example 1 except that the outer surfaces of the protective film and the separator had no surface coat.

Evaluation Test The optical member was punched into a 12-inch
After stacking the sheets sequentially and separating them on the horizontal plane,
The 100 sheets were stacked again, and the occurrence of glue chipping and glue contamination was examined one by one. It should be noted that the glue chip is 0.1 mm from the periphery.
When a chipping of the adhesive layer of 5 mm or more is observed, glue contamination means that the contamination is more clearly observed in the peripheral portion by visual observation than before the test.

The above results are shown in the following table.

[Brief description of the drawings]

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

[Explanation of symbols]

 1: Protective film 11: Surface coat 2: Optical material 21: Adhesive layer 3: Separator 31: Surface coat

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 Inside TEPCO (72) Inventor Yuji Kazuki 1-1-2 Shimohozumi, Ibaraki-shi, Osaka Nitto Denko Corporation F-term (reference) 2H049 BA02 BA06 BB13 BB23 BB24 BB25 BB26 BB27 BB28 BB33 BB36 BB43 BB51 BB54 BB63 BC22 4F100 AJ06 AK21 AK21G AK25G AK42 AK52 AT00B BA05 BA10D BA10E CB00G CB05G CC00D CC00E EJ91 JK20D JK20E JL06 JL13 JL13G JL14C JN00A JN10A JN30YYYD

Claims (2)

[Claims] 1. An optical material comprising a protective film on one side and a separator on the other side via an adhesive layer, wherein the protective film and the separator have a surface coat having a surface tension of 20 dyn / cm or less on the outer surface. Characteristic optical member. 2. The optical member according to claim 1, wherein the optical material has at least a polarizing plate or a retardation plate.