JPS58171007A - Manufacture of polarizing plate - Google Patents

Abstract

PURPOSE:To obtain a polarizing plate with superior adhesive strength, durability, thermal stability and polarizing characteristics by adhering soluble polyester resin films to a polarizing film with a liq. substance cotg. a prescribed vinyl monomer or oligomer as a principal component and a polymn. initiator. CONSTITUTION:One side of each of unstretched soluble polyethylene terephthalate films having 100mum thickness is coated with a liq. blend consisting of 20 parts polyester dimethyl methacrylate, 80 parts 2-ethylhexyl acrylate and 1 part 2,2'-azobis-(4-methoxy-2,4-dimethylvaleronitrile), and the films are stuck to both sides of a polarizing film contg. iodine and heated at 80 deg.C for 12hr to obtain a polarizing plate. The liq. blend makes the surface parts of the soluble 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 polarizing plate used in liquid crystal display devices and the like.

In recent years, liquid crystal display devices have been widely used in desktop electronic hand counters, electronic hour hands, instruments, etc., and the demand for polarizing plates used with AK has also increased.

In particular, for instrument 1, the use of 7 is being considered for automatic umbrellas, etc. used under harsh Qin conditions, but the polarized light used for these [K is more durable than ever before. and thermal stability are required.

Most of the conventional polarizing plates have a polarizing film provided with a surface layer made of optically transparent plastics such as acetates, polyacrylics, and the like.

However, these O-polarizing plates are difficult to use in cases where the conditions of use are relatively gentle, such as in desk-top electronic computers. When used in harsh conditions such as I@, due to its durability and thermal stability,
Improvements are requested.

In response to this problem, a method has been proposed in which the problems of durability and thermal stability are solved by using a polyester resin film as a surface protective layer on the surface of the polarizing film.

Therefore, a single polyester resin film has durability and thermal stability, but when viewed as a polarizing plate', the adhesive strength between the polarizing film and the polyester resin film is strong, and the polarizing film is The conditions for taking advantage of the Oq# properties of the polyester resin film are such that the polarization properties are not inhibited.

However, the conventionally used polarizing film, polyester resin film, and 011 adhesive have sufficient adhesive strength, but are not compounded into round adhesives made of F& polymers of saturated polyester resin and polyisocyanate compounds. Due to the polyincyanate compound contained in the film, the C1 adhesion operation is extremely complicated, and there is a problem that the polarizing properties of the polarizing film are deteriorated.

The present invention provides the foundation for a new method for manufacturing a polarizing plate that solves the problems of the prior art, and its gist is as follows:
When adhering the polarizing film and the soluble polyester film, a liquid material mainly composed of vinyl monomers and/or oligomers that dissolves or swells the surface layer of the film to make it sticky, is used. A polymerization agent is contained in either the lIIIMI film or the liquid material, and the liquid material is made to exist between the 1-light film and the m-lip film and heated to polymerize the liquid material. and bonding the polarizing film and the resin film. □ The second manufacturing method of the present invention consists of a polarizing film, a soluble polyester tree, and an Ij1 layer, which is generally made of 90% polyester f.
In adhering the llb fin to the mu through the [11 layer], the above! II. Vinyl monomer and/or vinyl monomer that causes at least the surface layer to become sticky or swollen.

uses a liquid material mainly composed of oligomers, contains a polymerization initiator in either the resin layer or the liquid material, and allows the liquid material to exist between the polarizing film and the resin layer. The liquid material is polymerized by heating, and the polarizing film and the insoluble polyester IIIFiI film are bonded together.

11th O
The R film and the polarizing film are attached with a light contact area, and the melted or swollen polyester and liquid polymer are formed into a microscopically non-uniform seabird structure at the interface. Strong adhesive strength can be obtained due to the adhesive properties, and since volatile substances such as solvents are not used, a favorable polarizing plate can be obtained without any factors that inhibit the Q polarization characteristics such as air. .

Also in the 112i#th invention, insoluble polyester W
II fat film bonding WJK has 1 soluble polyester resin p- that dissolves or swells in a liquid substance and becomes sticky, resulting in strong adhesive strength and excellent polarizing properties similar to the invention of ll. A polarizing plate is obtained.

A polarizing film used in carrying out the present invention is a polyvinyl alcohol film.

Partially formalized polyvinyl alcohol-based film, ethylene/vinyl acetate copolymer-based saponified film, and other water-visible polymeric films are coated with iodine and/or dichroic dyes. Dichroism*＠Polarizing film, polyvinyl alcohol film is dehydrated and polyene is oriented.Polyene-based 1 optical film, polyvinyl chloride film is dehydrochlorinated and polyene is oriented.Polyene polarizing film, etc. These have a thickness of 10 to 80 degrees of skin thickness.

sWJ of scissors film on one side or both sides of the cough light film
The polyester resin film used as the protective layer is a soluble or insoluble polyester resin film having a thickness of about 10 to 5007 m and made of polyester such as polyethylene terephthalate, polyethylene inphthalate, and fibutylene terephthalate.

Therefore, from the point of view of the optical properties of the polarizing plate, a nine-axis stretched soluble or insoluble polyester 4IlriI film that is abraded only in the vertical or horizontal axis direction, or a two-wheel stretched film that is ◆C stretched in the vertical and horizontal axes. A soluble or insoluble polyester #'1lil film is preferred, and a single stretched film is preferred since it can be used as a polarizing plate without distinction between the front and the back.

Preferred mono-stretched soluble or insoluble polyester III
! The f& film is stretched only in the longitudinal or transverse direction by at least 5-1 practically 50-500-6% at 100°C.
Heat set at 14 to 230°C for 5 minutes.

However, insoluble polyester! II! The unstretched, -axially stretched, and biaxially stretched films made of IiI are dissolved or ! Ninthly, the surface of the insoluble polyester film, which does not become adhesive and does not become sticky, cannot achieve the adhesive strength that is the objective of the present invention. It is a good idea to apply m% of a soluble saturated polyester resin to form a soluble polyester resin layer having a C1 thickness of about 3 to 507/i.

The vinyl monomers and/or oligos used in the practice of the present invention are soluble in the surface layer of the #-marked soluble non-polymers, or at least a portion of the surface of the above-mentioned WO 1. If it is filled with 1 il or 1 il and becomes sticky, #Kb (1) If it does not interfere with the polarization characteristics of the optical film, it will be unambiguous.
It's a complicated thing. Seven specific examples are as follows.

-Functional vinyl monomers: for example methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, cyclohexyl (meth)acrylate, s2-ethylhexyl (meth)acrylate , decyl (meth)acrylate, lauryl (meth)acrylate, alkyl or cycloalkyl acrylate or methacrylate, vinyl acetate, vinyl butetratepionate, (meth)acrylonitrile, styrene/, vinyltoluene, (meth)acrylic acid, 2
Polyfunctional vinyl monomers such as ethylene glycol di(
MeI) Acrylate 1, Ethylene glycol or propylene glycol diester of (meth)acrylic acid such as diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, tetramethylolpropane -Functional oligomers such as (meth)acrylate: For example, polyester (meth)acrylate obtained by reacting polyester resin with (meth)acrylic acid.
meth)acrylates, polyfunctional oligomers: for example, polyethylene glycol di(meth)acrylate, used in the reaction between epoxy resins and (meth)acrylic acid [the resulting epoxy(meth)acrylates, polyincyanate compounds and hydrocarbons] In the reaction with dialkyl (meth)acrylate (urethane (meth)acrylate obtained, polyester di(meth)acrylate or polyester di(meth)acrylate obtained by reaction of polyester resin and (meth)acrylic acid, etc. , These liquid materials mainly composed of vinyl monomers and/or oligomers are composed of one or more types of vinyl monomers and/or oligomers, but the viscosity of t depends on the coating workability. Considering this, it is practically preferable to adjust the i!IKgl in the range of 0°01 to 100 poise.

The polymerization initiator is one that decomposes when heated and polymerizes the vinyl monomer and/or oligomer.
Although not particularly restricted, organic peroxides such as benzoyl peroxide, methyl ethyl ketone peroxide, lauroyl peroxide, cumene hydroperoquinide, 2,2-azobisinbutyronitrile,
2.2 -Azobis-(4-methoxy-2,4-dimethylvaleronitrile), 1.1-Azobis(citalohexone-1-carbonitrile) and other azo-based compounds, as well as hydrogen peroxide, etc. Once the O reaction starts Those having a temperature of 20 to 100°C are preferably used.

The polymerization initiator is the soluble polyester resin film or the soluble saturated polyester resin 11. Alternatively, one of the liquid products (preferably wrinkled liquid products) containing the vinyl monomer and/or oligo i- as a main component VC, O, O1~
It is blended in an amount of 10% by weight, preferably from 0.1 to 4% by weight.

If the weight is 0 or 1, the polymerization of the liquid will be in the dark, and the desired adhesive strength will not be obtained.If the weight is 10 or more, the adhesive strength will be excessive and the adhesive strength will decrease, which is not preferable.

In addition, in I:, polymerization promoters such as N.y-dimethylaniline, 1-dimethylbuttluidine, cobalt naphthenate, heptanoate steel, thiourea, acetylurea, etc.
An appropriate amount of agent can be added. The addition of such a direct polymerization accelerator accelerates the polymerization of the liquid material that polymerizes upon heating, and forms the polyester resin film and the polarizing film in a short time.
This is preferable because it provides strong adhesion.

The manufacturing method of the present invention is to apply a liquid material mainly composed of the vinyl polymer and/or oligomer to a soluble polyester film or a soluble saturated polyester resin Tfj film.
Apply at a thickness of 1 to 100 mm/- and dissolve the film or layer surface or Jl+11! Apply a polarizing film to the coated adhesive surface and heat it for 5 minutes to 2 minutes at 25 to 100℃.
The liquid material is polymerized by heating for 4 hours to firmly adhere the soluble polyester resin film or insoluble polyester resin film and the polarizing film,
To provide a polarizing plate having excellent durability and thermal stability.

Below, an example of Book 5 @ Akira no Mi 1/IA is shown. In the middle part of the sentence or the ``-'', each n also means a unit of electric current.

Apply a liquid material consisting of the following composition (slP/d) to a piece of iodine-based polarizing film with a thickness of 1 Ks (slP/d). IK lamination was performed and heated at 80°C for 12 hours to obtain a 'C polarizing plate.

[Blend composition of liquid product]

Polyester dimethacrylate (-P average molecular weight 420)
20 parts) 11 [Iodine-based polarizing film] A polyvinyl alcohol-based film was immersed in an aqueous solution containing iodine 1Aaf1-1 potassium iodide concentrate 2- and boric acid 4mtt"P4m, and abraded 3 to 4 times at 50°C. and transmittance 4
A polarizing film (thickness: 30 meters) with a polarization degree of 92 mm was prepared.

Example 2 On one side of an insoluble polyethylene terephthalate film (4 x 75 Koejima) stretched only in the vertical axis direction, a +30-based soluble saturated polyester*i dissolved in a mixed solvent of methyl ethyl lactone and toluene was dried. The next 4 points are 2
Apply it to the surface of the surface that will give you a 0.0 m temperature and dry it at 130C for 10 minutes.

Next is the saturated polyester bridge! On the 1N11 side, pour 100 million cans (6P/s/) of the following liquid material, and apply
Ikkou at-rumor, t.914 profit, without heating at 80℃ for 12 hours.

[Distribution & composition of liquid 'jIII]

Polyester dimethacrylate (f average molecular weight 420)
30. Part acrylic butyl 7o Part 2.2'-Azobisin butyronitrile 1.51i1 Example 3 The liquid was as follows (using a coating amount of 3b-t1
Other than that, the operation was the same as in Example 2 (however, heating at 80°C
Remove the polarizing plate at 30 minutes.

[Blend composition of liquid product]

Styrene: 40 parts Cobalt naphthenate: 0.2 parts Actual Example 4 A polarizing plate was obtained in the same manner as in Example 2, except that the following 40 (coating amount sP/wl) was used as the liquid material.

[Blend composition of liquid product]

Butyl methacrylate 50 parts Methacrylic acid 50 parts Methyl ethyl ketone(-O11?nide) 1.5 parts Actual Example 5 The following were used as the liquid and the polarizing film, and the polarizing plate was prepared using the same procedure as in Actual Example 2. The amount of liquid applied is 49/d.

[Blend composition of liquid product]

Butyl methacrylate 80 parts Acrylic butyl 20ii11 Benzoyl peroxide t, S part [-optical film] 1 as a water catalyst for polyvinyl alcohol film
The film was immersed in an aqueous solution containing 0.1% acid, stretched 2 times for 9 times, then further stretched 2.5 times at 150°C and heat-treated to form a polyene. ,0
．． Aqueous solution containing dichroic dye (liquid temperature 30℃) K
Soak for 10 minutes.

The dye is adsorbed and oriented and dried to obtain a polyene-dichroic dye-based optical film (thickness: 25 am) having a neutral hue, a transmittance of 4 a*s, and a degree of polarization of 941.

Practical example 6 As a liquid material, use the one described in F (application amount 5p/w/>)
Other than that, the same operation as Actual Example 5 was performed to obtain K - C @ tip board.

[Blend composition of liquid product]

Butyl methacrylate 80 parts 40 parts of acrylic acid-2-hydroxy ethyl ester and 6
0 parts of 2.4-reactant with tolylene diinocyanate 20 parts of chestnut/hydroperoxide l. 5 parts Example 7 An insoluble polyester film stretched only in the vertical and horizontal directions (Jll Mitsue All) O) is dissolved in a warm solvent of methyl ethyl ketone and toluene, and 4 parts are added to a soluble saturated polyester resin based on +30 III. Add benzoyl peroxide (for till deafness) until the thickness after drying is 20. Apply gas to the surface of the sea urchin and dry. Next is this tree! % 1111, a liquid material consisting of 70 parts of butyl methacrylate and 30 parts of ethyl acrylate was applied at 5 t/vl and bonded to both sides of the polarizing film of Practical Example 1, and heated at 80°C for 12 hours to give priority to the polarizing plate. .

Example 8 Dissolved in methyl ethyl ketone-toluene mixed S medium ±3
Add 4 parts (based on the solid content) of 2.2-azobisinbutyronitrile to a soluble saturated polyester resin based on 0.01 and apply it to a thickness of 20 cm after drying. Degassed and dried with a vacuum pump for 1 hour at
This was applied to both sides of the polarizing film of Example 1, and heated at 80° C. for 12 hours to obtain a polarizing plate.

Reference Examples 1 to 2 in Φ Table 1, in which the first resultant composition of Actual Examples 1 to 8 is shown as the first member, correspond to Examples 2 to 3, and each r also did not provide a saturated polyester beak fat layer. 1. Test method in Table 1 Adhesion Two samples of polyester resin film and polarizing film. A cut is made at the interface between the polyester film and the polyester film, and it is determined whether or not the two can be peeled off.If the polyester finger film is broken and cannot be peeled off, it is determined that it cannot be peeled off, and if the polyester finger film is broken and peeled off, it is determined that it cannot be peeled off. Soil determined to be acceptable.

Polarization degree: Polarized light @O Superimpose two 017 angles cut at an angle of 46 degrees to the polarization axis to obtain the JP uniform parallel transmittance (!O
) and the direct transmission rate (, Yes), and insert these transmittances into the formula below at the current °C and measure.

It is clear from the above examples that the polarizing plate produced by the manufacturing method of the present invention has excellent adhesion between the polyester 411 resin film and the polarizing film, and has excellent durability and thermal stability. Author:

patent applicant Nitto Electric Works I! Aji-kai service Representative Sanbe Hijikata

Claims (1)

[Claims] 1) If optical film and soluble polyester! II A vinyl monomer and/or which dissolves or swells the surface layer portion of the film to make it sticky at the moment of adhering it to the resin film.
Or use a liquid substance containing oligomers as the main component before &! Either the resin film A or the liquid material contains a 6c polymerization initiator, the liquid material is present between the polarizing film and the tII resin film, and the liquid material is polymerized by heating at °C 7J, With the polarizing film! A method for manufacturing a polarizing plate that involves adhering III and film. The polarizing film and the soluble polyester III @ 411 were bonded to the insoluble polyester resin film through the skin sebum layer for at least 4 h beforehand.
Using a liquid material mainly composed of vinyl monomers and/or oligomers, which are made by dissolving or applying sL1i1 to make it sticky, add polymerized Rub to either one of the liquid materials.
The liquid substance is present between the polarizing film and 41 Chikyo, and the liquid substance is heated to polymerize the liquid substance, thereby bonding the polarizing film and the insoluble polyester resin film. A method for manufacturing a polarizing plate. 3) A method for manufacturing a polarizing plate according to claim 21, wherein the insoluble polyester resin film is a uniaxially stretched polyester 1116 film stretched in only one direction.