JP2000121832A - Adhered optical member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an adhered optical member which is formed by temporarily adhering and covering a tacky adhesive layer free from chipping and staining by a separator and hardly gives rise to glue chipping and glue staining in spite of transportation and storage in stack and other handling. SOLUTION: This adhered optical member is formed by temporarily adhering and covering the tacky adhesive layer 3 formed on the extreme surface of one or both surfaces of an optical member 2 with a separator 4 having a thickness of >=2 times the thickness of the tacky adhesive layer. As a result, the adhered optical member which hardly gives rise to the glue chipping and glue staining in spite of contact with other optical members, working jigs or operators, etc., at the time of transportation in stack, adhesion treatment, etc., may be obtained without changing the optical characteristics of the optical member.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adhesive type optical member which prevents an adhesive layer provided on the optical member from being chipped or stained.

[0002]

BACKGROUND ART Optical members used in a liquid crystal display (LCD), such as a polarizing plate, a retardation plate, and an elliptically polarizing plate obtained by laminating them, are key devices of the LCD and prevent variations in quality and increase the efficiency of LCD assembly. For the purpose, etc., it is used for transportation and assembling work as an adhesive optical member in a state where an adhesive layer made of an acrylic adhesive or the like for adhering to another member such as a liquid crystal cell is attached to the outermost surface in advance. . In this case, if the adhesive layer provided on the outermost surface is left exposed, contaminants which cause a decrease in adhesive strength or impaired visibility are likely to adhere to the adhesive layer. Measures have been taken.

[0003] Conventionally, the above-mentioned separator, which has been separated and removed as an unnecessary material after achieving the purpose of the protective cover, is discarded. Therefore, a plastic having a thickness of 20 to 30 µm is required for effective use of resources. Films were commonly used.

However, in the case of conventional adhesive type optical members, when they are stacked and transported or stored and then the separator is peeled off and provided for bonding, the adhesive layer (glue), particularly the end face thereof, is chipped. There is a problem that the toner cannot be subjected to the bonding process due to the occurrence of stains or stains.

[0005]

The above-mentioned chipping and glue stains come into contact with other optical members, work jigs and workers when the adhesive type optical members are transported in a stacked state or are subjected to an adhesive treatment. However, it is difficult to avoid such contact. Accordingly, an object of the present invention is to develop an adhesive optical member that is less likely to cause chipping or adhesive stains even when the adhesive layer having no chips or stains is temporarily attached with a separator and stacked, transported and stored, and subjected to other handling. I do.

[0006]

According to the present invention, an adhesive layer provided on the outermost surface of one or both surfaces of an optical member is temporarily covered with a separator having a thickness of at least twice the thickness of the adhesive layer. An object of the present invention is to provide a bonded optical member.

[0007]

According to the present invention, there is provided an adhesive optical member which is less likely to cause glue chipping or glue contamination even when it comes into contact with another optical member, a working jig, an operator, or the like during stacking transportation or bonding processing. It can be obtained without changing the optical characteristics of the optical member.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The adhesive type optical member according to the present invention is a temporary adhesion cover in which an adhesive layer provided on one or both outermost surfaces of the optical member is provided with a separator having a thickness of twice or more the thickness of the adhesive layer. Consisting of An example is shown in FIG. 2
Is an optical member, 3 is an adhesive layer, 4 is a separator, and 1 is a protective film as required.

As the optical member, for example, a polarizing plate, a retardation plate, an elliptically polarizing plate obtained by laminating the polarizing plate, an appropriate member used for forming a liquid crystal display device or the like can be used, and the type thereof is not particularly limited. Therefore, the polarizing plate may be a reflection type or the like. Also, the phase difference plate is や or ４
It may have an appropriate purpose, such as a wave plate such as that described above, and viewing angle compensation. In the case of a laminated optical member 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 thickness of the polarizing film is usually 5 to 80 μm, but is not limited thereto. The polarizing film may have a transparent protective layer such as a protective film on one or both sides.

On the other hand, the reflection type polarizing plate is provided with a reflection layer on the polarizing plate, and is used to form 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 reflection type polarizing plate can be formed by an appropriate method such as a method in which a reflecting layer made of metal or the like is provided on one side of the polarizing plate via a transparent protective layer or the like, if necessary.
The above-mentioned polarizing plate, in particular, the transparent protective layer provided on one or both sides of the polarizing film as required can also serve as the protective film 1 as shown in the figure.

Specific examples of the reflective polarizing plate include a transparent protective layer that 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-mentioned fine uneven structure has an advantage that the incident light is diffused by irregular reflection to prevent directivity and glare, and to suppress uneven brightness.
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 reflective layer having a fine uneven structure reflecting the fine uneven structure on the surface of the transparent protective layer is formed by, for example, making the metal transparent by an appropriate method such as an evaporation method such as a vacuum evaporation method, an ion plating method, or a sputtering method, or a plating method. It can be performed by a method of directly attaching to the surface of the protective layer.

The formation of the above-mentioned protective film or a transparent protective layer on a polarizing plate, which is disposed as necessary for the purpose of protecting the surface of the optical member, etc., requires transparency, mechanical strength, thermal stability, and moisture shielding. Polymers having excellent properties and the like are preferably used. Examples thereof include polyester resins and acetate resins, polyethersulfone resins and polycarbonate resins, polyamide resins and polyimide resins, polyolefin resins and acrylic resins, or acrylic, urethane and acrylic urethane resins. And thermosetting resins such as epoxy resins and silicone resins, and ultraviolet curing resins.

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 included in the formation of the transparent protective layer having the fine surface uneven 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 generally 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 according to the purpose of use such as, for example, various wavelength plates or those intended for compensation of a viewing angle or the like due to birefringence of a liquid crystal layer, and may have two or more types. A retardation plate may be laminated to control optical characteristics such as retardation.

The above-mentioned elliptically polarizing plate or reflection type elliptically polarizing plate is obtained by laminating a polarizing plate or a reflection type polarizing plate and a retardation plate in an appropriate combination. Such an elliptically polarizing plate or the like can also be formed by sequentially and separately laminating a (reflection type) polarizing plate and a retardation plate in a manufacturing process of a liquid crystal display device so as to form a combination. An optical member such as a polarizing plate has an advantage that the stability of quality and laminating workability are excellent and the production efficiency of a liquid crystal display device or the like can be improved.

The adhesive layer provided on one or both outermost surfaces of the optical member is for bonding to another member such as a liquid crystal cell. For the formation thereof, for example, an adhesive substance or an adhesive having an appropriate polymer such as an acrylic polymer or a silicone-based polymer, a polyester or a polyurethane, a polyamide or a polyether, a fluorine-based or a rubber-based polymer as a base polymer can be used. There is no particular limitation. Among them, those having excellent optical transparency such as acrylic pressure-sensitive adhesives, exhibiting appropriate wettability, cohesiveness and adhesive pressure-sensitive adhesive properties, and having excellent weather resistance and heat resistance can be preferably used.

In addition, in addition to the above, prevention of foaming and peeling phenomena due to moisture absorption, prevention of deterioration of optical characteristics due to differences in thermal expansion, prevention of liquid crystal cell warpage, and formation of a liquid crystal display device having high quality and excellent durability. In view of the above, an adhesive layer having a low moisture absorption rate and excellent heat resistance is preferable.

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. Further, an adhesive layer containing fine particles and exhibiting light diffusibility may be used.

The attachment of the adhesive layer to one or both sides of the optical member can be performed by an appropriate method. By the way, as an example,
For example, an adhesive substance or a composition thereof is dissolved or dispersed in a solvent composed of an appropriate solvent alone or a mixture of appropriate solvents such as toluene and ethyl acetate to prepare an adhesive liquid of about 10 to 40% by weight, and it is cast. Examples thereof include a method in which the adhesive layer is directly provided on the optical member by an appropriate development method such as a method or a coating method, or a method in which an adhesive layer is formed on a separator and transferred to the optical member in accordance with the above.

The adhesive layer may be provided on one or both sides of the optical member as a superposed layer of different compositions or types. When the optical member is provided on both sides, an adhesive layer having a different composition, type, thickness, and the like may be formed on the front and back surfaces of the optical member. The thickness of the pressure-sensitive adhesive layer can be appropriately determined depending on the purpose of use, adhesive strength, and the like, and is generally 1 to 500 μm, preferably 5 to 20 μm.
0 μm, especially 10 to 100 μm.

The separator 4 is temporarily attached to the exposed surface of the adhesive layer for the purpose of preventing contamination or the like until it is put to practical use as shown in the figure, and covered. In the present invention, a separator having a thickness of at least twice, more preferably at least 2.2 times, especially at least 2.5 times the thickness of the adhesive layer to be temporarily attached is used. Thereby, it is possible to almost prevent the adhesive layer from coming into contact with the adhesive layer in a usual handling state, and it is possible to drastically avoid glue chipping and glue contamination.

That is, even in the adhesive type optical member according to the present invention, since the thickness side of the adhesive layer is exposed on the side surface, contact from the vertical direction on the side surface of the optical member cannot be prevented. Although it is difficult to prevent this, when approaching from an oblique direction, etc., deviated from the vertical direction, the separator will come into contact with the separator before the adhesive surface due to the thickness effect of the separator, thereby dramatically avoiding contact with the adhesive surface. Thus, it is possible to prevent glue chipping and glue contamination due to ordinary handling conditions.

The separator which can be preferably used in view of the above-mentioned prevention of contact and the like has a thickness of at least 40 μm at least in addition to the condition that the thickness is twice or more than that of the above-mentioned adhesive layer.

Except for the above thickness conditions, for example, a suitable thin leaf such as a plastic film or a rubber sheet, paper or cloth, a nonwoven fabric or a net, a foamed sheet or a metal foil, or a laminate thereof may be used. Appropriate conventional materials, such as those coated with an appropriate release agent such as silicone, long-chain alkyl, fluorine, or molybdenum sulfide, can be used.

In the present invention, the respective layers such as a polarizing plate and a retardation plate, a protective film and a transparent protective layer, and an adhesive layer which form the above-mentioned optical member are formed of, for example, a salicylate compound, a benzophenol compound, a benzophenol compound or a benzophenol compound. A compound having an ultraviolet absorbing ability by an appropriate method such as a method of treating with an ultraviolet absorbent such as a triazole compound, a cyanoacrylate compound, or a nickel complex compound may be used.

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

[0030]

EXAMPLE 1 A 50 μm thick PET film provided with a surface coat of a silicone release agent on a separator having a thickness of 2 μm.
A 5 μm acrylic pressure-sensitive adhesive layer is adhered to one side of a 180 μm-thick polarizing plate provided with transparent protective layers on both sides of a polarizing film together with its separator, and the protective film is bonded to the other side of the polarizing plate to form an adhesive optical member. After that, it was punched into a 12-inch size and stacked 100 times.

Example 2 The thickness of the adhesive layer was 50 μm, and the thickness of the separator was 12 μm.
Except for 5 μm, an adhesive optical member was obtained in the same manner as in Example 1, and was punched out into a 12-inch size and stacked 100 times.

Comparative Example 1 An adhesive optical member was obtained in the same manner as in Example 1 except that the thickness of the separator was changed to 40 μm.

Comparative Example 2 An adhesive optical member was obtained in the same manner as in Example 2 except that the thickness of the separator was changed to 50 μm.

Evaluation Test After the stacks obtained in the examples and comparative examples were separated by hand, 100 sheets were stacked again.
The rate of occurrence of glue chipping (a chip of 0.5 mm or more from the peripheral part) and glue contamination (clearer stain progression in the peripheral part than before the test) was examined. In the initial stacking, those without glue chipping and glue contamination were carefully selected and used.

The 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 2: optical member 3: adhesive layer 4: separator

Continuation of the front page (72) Inventor Tominari Araki 1-1-2 Shimohozumi, Ibaraki-shi, Osaka Nitto Denko Corporation (72) Inventor Tomomori Masada 1-1-2 Shimohozumi, Ibaraki-shi, Osaka Nitto Denko F term (reference) 2H049 BA02 BA06 BB23 BB54 BB63 5G435 AA00 FF05 HH02 KK07

Claims (2)

[Claims] 1. An adhesive type wherein an adhesive layer provided on the outermost surface of one or both surfaces of an optical member is temporarily covered with a separator having a thickness of at least twice the thickness of the adhesive layer. Optical members. 2. The optical member according to claim 1, wherein the optical member has at least a polarizing plate or a retardation plate, and the thickness of the separator is 4 or more.
An adhesive optical member having a thickness of 0 μm or more.