JPS58171008A - Manufacture of polarizing plate - Google Patents

Abstract

PURPOSE:To obtain a polarizing plate with superior adhesive strength, durabiliby, thermal stability and polarizing characteristics by adhering polyacrylic resin films to a polarizing film with a liq. substance contg. a prescribed vinyl monomer or oligomer as a principal component and a polymn. initiator. CONSTITUTION:One side of each of polyacrylic resin films contg. methyl methacrylate as a principal component is coated with a liq. mixture consisting of 100 parts methyl methacrylate, 10 parts glycidyl methacrylate and 1 part azobisisobutyronitrile, and the films are stuck to both sides of a polarizing film, press-bonded together, and allowed to stand in an oven kept at 90 deg.C for 60min to obtain a polarizing plate. The liq. mixture makes the surface parts of the polyacrylic resin films tacky by dissolution or swelling, so the polarizing plate with superior adhesive strength, durability and polarizing characteristics is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a b-polarizing plate used in liquid crystal display devices and the like.

BACKGROUND ART In recent years, a housing crystal display device that combines a crystal display cell and a polarizing plate has been widely used in desktop electronic computers, electronic watches, and the like.

Such a polarizing plate generally includes a polarizing film, a surface preservation layer, and one
．． It is composed of plastic film such as acetate film or polyacrylic resin film.

However, for adhesion between polarizing films and plastic films, polyurethane adhesives are mostly used from the viewpoint of optical properties and durability of the base plate.

1. 1. Urethane adhesives have a relatively weak initial adhesive strength and require a long time to harden to a degree of hardening of 6. Therefore, there are 9 problems in that the adhesive work is complicated.

Therefore, an object of the present invention is to provide a method for manufacturing a polarizing plate that has strong initial adhesive strength and can be cured in a short time.

Such an object of the present invention is to use a vinyl monomer that dissolves or swells the surface m portion of the resin film to make it sticky when adhering a polarizing film and a polyacrylic resin film as a surface protective layer of the film. and/or a liquid material containing an oligomer as a main component... containing either the above-mentioned ST fat film or the liquid material (a polymerization initiation period), This is achieved by heating the liquid substance in the presence of the liquid substance to polymerize the liquid substance and bonding the polarizing film and the resin film together.

According to the present invention, the surface layer portion of the polyacrylic resin film that is adhered to the polarizing film is connected or swollen with a liquid material mainly composed of vinyl monomer and/or oligomer to become sticky. % polarized light) 4 lume surface VC@Yi and is large, so there is contact with the adhesive area, and the optical film and polyacrylic resin film can be bonded firmly and in a short time.

Polarizing films used in carrying out the present invention include hydrophilic polymer films such as polyvinyl alcohol films, partially formalized polyvinyl alcohol films, and saponified ethylene-vinyl acetate copolymer films. Iodine and/or dye-based polarized light film in which iodine and/or dichroic dye is adsorbed and oriented on J! Polyene polarizing films made by dehydrating a polyvinyl alcohol film or dehydrating a polyvinyl chloride film and then orienting polyene are mentioned, and these films generally have a thickness of about $110 to 80 μm. Things are used because they have them.

The polyacrylic resin film used as the surface retention layer of the polarizing film includes (meth)acrylic acid esters such as methyl acrylate, methyl methacrylate, ethyl acrylate, Metac IJ 7L/Shun ethyl, etc. Functional monomers such as meth)acrylic acid, maleic anhydride, itaconic acid, 2-hydroxyethyl (meth)acrylate, and acrylamide and unsaturated compounds such as styrene, vinyl acetate, and (meth)acrylonitrile can be combined with tg. 100-50: 0-20: O-3G (
The weight ratio of unpolymerized and copolymerized products is even higher.
u Copolymer: A crosslinked copolymer which has not been crosslinked with an organic reagent such as a polyincyanate apricot is prepared by a conventional method 11! (Thickness Tsuri 311-10Q Voice ■) A made-up item is used.

In addition, the vinyl monomer and/or au rubber may be used as long as it melts or swells the surface layer of the polyacrylic resin film to make it sticky. can.

- Functional vinyl monomers: such as methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, hexyl (meth)acrylate, 2-ethylhexyl A/(meth)acrylate, ) acrylate, alkyl or cycloalkyl acrylate or methacrylate such as decyl (meth)acrylate, lacryl (meth)acrylate, vinyl acetate, propionic vinyl, (meth)acrylic nitrile, styrene, vinyltoluene, (meth)acrylic acid,
(meth) such as 2-hydroxyethyl (meth)arylate or 2-hydroxyalkyl (meth)acrylate
Hydroxy ester of acrylic acid, Gusosigil (Me#)
acrylate, diethylaminoethyl [meth)acrylate, etc. 1. Polyfunctional vinyl monomers: (meth) such as ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, etc. Ethylene glycol or hapropylene glycol diester of acrylic acid, trimethylolpropane tri(meth)acrylate,
-Functional oligomers such as tetramethylolpropane tetra(meth)acrylate; multi-functional oligomers such as polyester 7-(meth)acrylate obtained by reaction of polyester resin and (meth)acrylic acid; For example, polyethylene glycol di(meth)acrylate, obtained by the reaction between an epoxy resin and (meth)acrylic acid, epoxy(meth)acrylate, polyisocyanate, and phrethane obtained by the reaction between a polyisocyanate compound and a hydroxyalkyl(meth)acrylate. (meth)acrylate,
Polyester di(meth)acrylate or polyether di(meth)acrylate obtained by the reaction of polyester resin and (meth)acrylic acid, etc., because the liquid material contains these vinyl monomers and/or oligomers as the main component, Monomer and/or oligomer 〇 One or more types are contained at the bottom of the tank, but considering coating workability, the viscosity is in the range of 0.01 to 1.0 voids, practically 50 voids or less IIc. # It is preferable to prepare the liquid material at the interface with the polyacrylic resin film 7 polarizing film, and the thickness of the polyacrylic resin film is 100μ11st - 1 to 500f/11/
, preferably tL< is applied in the range of 1G to 3QOf waste.

The combination of these vinyl monomers and/or oligomers and the polyacrylic resin film may be the same, but according to experiments repeatedly conducted by the present inventors, the surface layer portion of the film is A combination with poor adhesive properties, such as a system that becomes slightly cloudy when dissolved or swollen, is used, but a combination with which strong adhesive strength can be obtained is used. Further, an acrylic co-electric compound having good compatibility may be added to the vinyl monomer and/or oligomer in an amount of 30% by weight or less (M%) or less for the purpose of improving coating workability.

A 1F polymerization initiator is added to the liquid material mainly composed of vinyl monomers and/or oligomers, which causes the liquid material to initiate polymerization upon heating. However, the initiator may be blended into the polyacrylic resin film.

As the polymerization initiator, organic peroxides such as benzoyl peroxide, methyl ethyl ketone peroxide, lacroyl bar oxide, and cumene hydroxy peroxide, 2,2-azobisincy (2,4-dimethylvaleronitrile), 1,1-azobis( Cyclohexane-1
- carbonitrile), other hydrogen peroxide, ammonium persulfate, etc., the reaction initiation temperature is 20 to I
oob are used and these are 0. It is blended in an amount of 1 to 10 liters by weight, practically 1 to 4 liters by weight.

In addition, the above polyacrylic resin film or liquid material includes:
N,N-dimethylaniline, N,N-dimethylk Ha9
) It is possible to add appropriate amounts of electrostatic polymerization accelerators such as leucine, naphthene, thiourea, and acetylurea. The effect is because of it.

The manufacturing method of the present invention involves coating a polyacrylic resin film with a wavy material mainly composed of a vinyl monomer and/or oligomer containing a model number 1 initiator to a thickness of 0.1-1091β. (Dissolve or make II# surface sticky,
Polarized light on this applied adhesive m
N1 @ 01)? The wavy material is polymerized by heating at a pressure of 0.1 N2 to provide a polarizing plate in which the polyacrylic resin 74 and the polarizing film are firmly attached.

In the above manufacturing method, wheat 1iit1. of the polarizing film is prepared in advance.
Polyisocyanate compounds such as 6-hexane diisocyanate, dicyclohexylmethane diisocyanate, ) rylene diisocyanate, liphenylmethane diisocyanate, tribueni p5 methane triincyanate, and modified products thereof, or vinyltriethoxysilane, r-glycidoxy Probyltrimethoxysilane, N
-Performing surface cleaning using electrostatic silane compounds such as β (aminoethyl) r-aminopropyltriethoxysilane and l-aminopropyltriethoxysilane makes it possible to produce polarizing plates with stronger adhesive strength. can get.

In the following description of the embodiments of the present invention, "0" in the middle means "1" in the middle.

Example 1 101 parts of a liquid mixture of 100 parts of methyl methacrylate, 106 fl of glycidyl methacrylate, and 1 WIA of ambisisobutyronitrile was placed on one side of a 30 μm thick polyacrylic resin film mainly composed of methyl methacrylate.
/111 was coated, and this was adhered and pressed to both sides of the polarizing film obtained by the method □ as described below, and was left open for 60 minutes at 90° C. to obtain a polarizing plate.

Polarizing film〉 Polyvinyl alcohol film with an iodine concentration of 1 weight,
A polarizing film (thickness: 30
Voice l) was created.

Example 2 A piece of polyacrylic resin film with a thickness of s50 cm and containing methyl metatallylate as the main component [K, 100 parts of punal methacrylate, 10 parts of styrene, and benzoyl peroxy) O, SS mixed liquid form Apply St/Ill to this 1
Example 1 Polarized light 7 (laminated and pressure-bonded on both sides of the lume, heated for 1 minute in an open chamber maintained at 70 tK,
lltK! 4 hours later, get a polarizing plate.

Example 1 One side of a polyacrylic resin film with a thickness of 820 mm containing methacrylate as the main component and methyl methacrylate as the main component, and 5' il of methacrylic acid as the main component.
,) lylene diisocyanate) $s.

A liquid mixture consisting of 10 parts of a copolymer of methacrylic methyl: acrylic soethyl 1.:1 and 1 part of 2,2'-azobis-(4-methoxy-2,4-dimethylvaleronitrile) was mixed at 20 f/ dfl1M film was pasted on both sides of a polarizing film obtained by the following method, pressure-bonded, and heated at 80°C.
Heat it for 20 minutes to obtain a polarizing plate.

(Polarizing film) A polyvinyl alcohol film was dehydrated in an aqueous solution containing 0.1 weight Wk of salt e as a catalyst (while immersed, stretched to 2 times its original size, and then further stretched to 2.5 @ at 15°C). To form polyene by stretching and heat treatment.

Next, the film formed with polyene was immersed in an aqueous solution (liquid temperature 30°C) containing a dichroic dye of t-0.1 weight for 10 minutes to adsorb and orient the dye, and then dried to a neutral hue. Therefore, a polyene-dichroic dye-based polarizing film (thickness 25 μm) f having a transmittance of 43% and a polarization degree of 94 was obtained.

Example 5 2.2-A part was added to 100 parts of a resin solution consisting of a methacrylate methyl-ethyl acrylate copolymer, and this was placed on a mold release liner to a thickness of 30 mW after drying. To obtain a polyacrylic resin buoy, cast it as shown. One side of this film contains 16 methacrylic
01I and methacrylic glycidyl 20° to 20°C were coated on both sides of the polarizing film (Example 1#) and heated at 80° C. for 12020 minutes.

Example 6 On one side of an acrylic resin film made of ethyl methacrylate and methacrylate and having a thickness of 20 mm,
Polyester dimetallylic acid (average molecular weight 54G) 3
0 parts, 1 part to 1 part of methimethacrylate ksO was applied for 2017 days, and this was attached to both sides of the polarizing film of Example 1, and heated at 8°C for 120 minutes to obtain polarized light.

@1 Table shows the test results of Example 1-1.

Test method in Table 1 @ Table 1 Adhesion: A cut is made at the interface between the polyacrylic resin film of the sample and the polarizing film, and it is measured whether the two can be peeled off. It was determined that 9 pieces could not be peeled off.

Polarization degree: Average parallel transmittance (YO) by stacking two samples cut at a 45 degree angle to the polarization axis of the polarizing plate.
and the average orthogonal transmittance (Yl@), and apply these transmittances to the formula below.

As is clear from the above examples, the polarizing plate produced by the manufacturing method of the present invention has excellent adhesion between the polyacrylic resin film and the polarizing film, and is notable for its durability and thermal stability. be.

patent applicant Nitto Electric Industry Co., Ltd. Representative Kamigata Sanbe 49-

Claims (1)

[Scope of Claims] A vinyl monomer which is bonded to a polarizing film and a polyacrylic resin 7 (luminous material) as a surface-preservation agent for the film, and which is made to adhere to the surface layer of the resin film by melting or 511Ilt. The polarizing film and the JlIMI film are prepared by using a h@-shaped material tube mainly composed of silica and/or oil sesame, and containing an initiator in each of the resin film, film, or liquid material. A #fertilizer liquid is present in the solution and heated to polymerize the liquid and bond the polarizing film and the resin film.All features and ↑b
Manufacturing method of polarizing plate.