JPS6352578B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a transparent film or sheet, and more particularly to a transparent film or sheet that exhibits good performance in terms of moisture resistance, heat resistance, Young's modulus, and flexibility.

Panels with glass as a substrate have traditionally been applied to various devices and equipment, but such panels are limited by the mechanical strength of the glass, so it is difficult to make the panels thinner as currently required. It also has the disadvantage that it is not suitable for continuous production (lengthening of membranes), which is essential for improving productivity. In addition, the vulnerability to impact has once again been pointed out, and panels using plastic films (or sheets) as substrates are attracting attention.

However, when using such a panel, it has been found that the following new problems arise.

(1) Due to its low chemical stability, it easily deteriorates if it is affected by organic chemicals that come into contact with it during pattern formation or liquid crystal that is sealed in the product stage.

(2) Low moisture resistance.

(3) Flexibility is still insufficient and there is no stiffness, so workability during panel assembly is poor.

(4) Although it is possible to make the film thinner, problems such as panel warping, bending, and uneven gaps are likely to occur.

(5) When attaching the polarizing plate, an adhesive that easily foams when heated is used, so air bubbles may be generated by the heat.

(6) Insufficient heat resistance and dimensional stability.

The present invention has been made with the aim of establishing a technology that can more significantly exhibit the effects of using a plastic film as a substrate, while paying attention to such problems. The object of the present invention is to provide a transparent film or sheet that can be applied in various ways in the production of.

That is, the transparent film or sheet of the present invention is
Made of synthetic resin material with a heat distortion temperature of 80℃ or higher,
It is protected by a cured film that has a retardation value of 30 mμ or less and a heat distortion temperature of 80°C or more.The structure and operation of the present invention will be described below with reference to each component and specific examples. Reveal the effects.

The film (or sheet) of the present invention must have excellent heat resistance and dimensional stability, with a heat distortion temperature of 80°C.
Must be above 130℃, more preferably 130℃
That's all. That is, if the thermal deformation temperature is less than 80°C, it is disadvantageous that the film will be thermally deformed during the subsequent formation of a cured film or various applications of the film of the present invention, such as during the formation of a conductive layer or the treatment with a sealant. Further, the transparent film used in the present invention must have a retardation value (R value) of 30 mμ or less. The R value is expressed as the product of the film thickness d and the absolute value |n ₁ -n ₂ | of the difference in two refractive indices in the direction perpendicular to the film.

R = d | n ₁ - _{n 2} | (where n ₁ is the refractive index in any direction, n ₂ is the refractive index in the direction orthogonal to the n ₁ direction) If this R value exceeds 30 mμ, the appropriate viewing angle for the panel will be As the width becomes narrower, interference fringes occur, and when applied to, for example, a liquid crystal display device, the readability deteriorates.

The synthetic resin that is the material for the film that satisfies these conditions is amorphous, and if it is crystalline, it will partially crystallize, resulting in poor transparency and optical anisotropy. The problem is that the R value becomes high. Any resin that satisfies these conditions can be used in the present invention, but considering the use of the present invention, resins that have excellent chemical stability such as organic chemical resistance and liquid crystal resistance as described above should be used. Something is desired. Therefore, the synthetic resins that can be used in the present invention include poly-4-methylpentene-1, polyacrylonitrile resin, phenoxy ether type polymer, phenoxy ether type crosslinked polymer, polyphenylene oxide type resin, and epoxy resin. Examples include cellulose resins, vinyl resins, styrene copolymer resins, polycarbonate resins, polysulfone resins, polyethersulfone resins, polyarylene ester resins, etc., but in the present invention, preferred synthetic resins include The resin is a phenoxy ether type polymer or a phenoxy ether type crosslinked polymer represented by the following general formula.

(In the formula, R ¹ to ^{R 6} are each hydrogen or a carbon number of 1 to 3
R ⁷ is a lower alkyl group having 2 to 4 carbon atoms, m is an integer of 0 to 3, and n is an integer of 20 to 300.) In the above general formula, R ¹ to R ⁶ represent Examples of the lower alkyl group having 1 to 3 carbon atoms include saturated lower alkyl groups such as methyl, ethyl, propyl, and isopropyl, and the lower alkyl group having 2 to 4 carbon atoms represented by R ⁷
Examples of the lower alkylene group include ethylene, propylene, trimethylene, and butylene. The phenoxy ether type polymer shown above is a known polymer per se, and has the general formula It is obtained by condensing epichlorohydrin with bisphenol A or an analog thereof represented by the formula (wherein R ¹ to ^{R 7} and m have the same meanings as above).

The above phenoxy ether type polymer may be applied to the present invention with its chemical structure as it is, but if necessary, the active hydrogen moiety, specifically the hydrogen moiety of the hydroxyl group, may be polyfunctionalized. It may be used in the present invention as a crosslinked polymer obtained by subjecting a compound to a crosslinking reaction. Such polyfunctional compounds include groups that have high reaction activity with hydroxyl groups, such as isocyanato groups, carboxy groups, and reactive derivative groups in carboxyl groups (such as halides, activated amides, active esters, etc.).
(acid anhydride group, etc.), mercapto group, etc., such as tolylene diisocyanate, m-phenylene diisocyanate,
Polyisocyanates such as P-phenylene diisocyanate and 4,4'-diphenylmethane diisocyanate and their polyhydric alcohol adducts; blocked polyisocyanates such as phenol blocked tolylene diisocyanate; adipic acid,
Polycarboxylic acids and reactive derivatives at the carboxy group such as tartaric acid, sebacic acid, phthalic acid; mercapto-substituted organic carboxylic acids such as thioglycol;
In addition to the above, epichlorohydrin, sodium thiosulfate, melamine-formaldehyde, phenol resin, urea-formaldehyde resin, etc. can also be used.

These synthetic resins are formed into films or sheets by the usual wet film forming method, dry film forming method, and melt film forming method, but considering the optical isotropy of the film, dry film forming law is optimal. The thickness of the film is usually 5-1000μ, preferably 20-200μ. In other words, if it is less than 5μ, it will be difficult to stack the polarizing element film, and if it exceeds 1000μ, it will be difficult to wind it into a roll, and the effect of improving productivity by making it longer will not be obtained, and it will be difficult to roll it. If it is rolled up too much, it may curl or warp when it is made into a product panel.

In the present invention, at least one side of the film is coated with or impregnated with a curable resin and/or a monomer, and then cured so that the heat distortion temperature is 80°C.
Thus, a substantially optically isotropic composite film is formed. This provides organic chemical resistance and liquid crystal resistance, and further improves various performances such as heat resistance, moisture permeation resistance, and adhesion of the conductive layer. Types of curable resins and monomers,
There are no restrictions on the polymerization initiator, the curing catalyst, the coating or impregnating method on the film, the adhesion improvement treatment method on the film, the curing method, the thickness of the cured film, etc., but in the present invention, the curable resin and/or Alternatively, in order to take advantage of the characteristics of the synthetic resin material, the monomer must be able to form a cured film with a heat distortion temperature of 80°C or higher, such as acrylic resin, as shown in the general formula above, etc. Examples of preferred curable monomers include phenoxy ether type crosslinked polymers, epoxy resins, melamine resins, urea resins, phenol resins, urethane resins, and unsaturated polyester resins. A polyfunctional unsaturated monomer or/and its initial radical whose main component is a compound containing three or more acryloyloxy groups and/or methacryloyloxy groups (hereinafter referred to as polyfunctional (meth)acryloyloxy group-containing compound) It can refer to a composition based on a reactant. Particularly preferably, the polyfunctional unsaturated monomer containing at least three or more (meth)acryloyloxy groups in the molecule is 50% by weight or more, preferably 70% by weight based on the total unsaturated monomers. , particularly preferably 90
Unsaturated monomer mixture containing at least % by weight or/
and its initial radical reactant.

Examples of polyfunctional unsaturated monomers containing three or more (meth)acryloyloxy groups in the molecule include pentaerythritol tetra(meth)acrylate, pentaerythritol tri(meth)acrylate, and trimethylolpropane tri(meth)acrylate. , trimethylolethane tri(meth)acrylate, dipentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, and the like. Unsaturated monomers that can be used together with these include unsaturated monomers having two or one (meth)acryloyloxy groups in the molecule and other vinyl monomers. The above-mentioned bifunctional monomer is a hydrocarbon residue, a polyether residue, or a polyester residue in which the group bonding between each (meth)acryloyloxy group in one molecule contains 100 or more carbon atoms. Monomers are preferred. For example, ethylene glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate
Examples include acrylate, polyethylene glycol di(meth)acrylate, polytetramethylene glycol di(meth)acrylate, and polyester diol di(meth)acrylate. The above monofunctional monomer is 2-hydroxymethyl (meth)
Acrylate, glycidyl (meth)acrylate, (meth)acrylic acid, quaternary ammonium salts of (meth)acrylic esters, etc. can be used.
These can be dissolved in a solvent if necessary, and can also be used together with a reaction initiator, catalyst, ultraviolet absorber, other stabilizers, lubricants, and the like. The coating or impregnation method may be any commonly used method such as spray method, gravure coating method, reverse coating method, kiss coating method, Meyer bar method, air knife method, dip method, etc. As a curing method, heating (usually 80 to 200°C, 10 seconds to 1 hour), actinic ray irradiation (usually ultraviolet rays with a wavelength of 200 to 400 mμ), and other electromagnetic ray irradiation (electron beam, alpha ray, etc.) can be used. The cured layer has a thickness of 1μ or more on at least one side of the amorphous synthetic resin film or sheet used in the present invention.
Formed with a thickness of 50μ or less, preferably 2μ or more and 20μ or less,
The layer may be embedded inside the amorphous synthetic resin layer or may be chemically bonded to the amorphous synthetic resin layer. If the cured layer has a thickness of less than 1μ, sufficient chemical resistance, liquid crystal resistance, moisture permeability, and heat resistance cannot be imparted, and if it exceeds 50μ, it is unfavorable in terms of flexibility and adhesiveness. After curing, the composite film has a heat distortion temperature of 80°C or higher and an R value of 30 mμ. This is due to the following reasons.

(1) The composite film was made by using a resin with a heat distortion temperature of 80℃ or higher for the base film, and a resin layer with a heat distortion temperature of 80℃ or higher was selected as a cured film. have characteristics.

(2) The cured layer is formed by dry coating using a solvent in consideration of optical isotropy (in the case of melt-forming, consideration is given to avoid melt orientation), so the R value does not increase.

The transparent film or sheet of the present invention having such a structure can be used as a panel material for displays such as watches and calculators, light amount adjustment devices, optical shutter graphic displays, etc. In addition to liquid crystal display devices, the transparent film or sheet of the present invention can be used as an electrode for electroluminescent material, It can be used as an electrode for a photoconductive photoreceptor, as a surface heating element for attaching windows to aircraft, trains, automobiles, etc., and as a selectively permeable film for attaching windows to solar energy collectors, greenhouses, buildings, etc. Furthermore, when used in a liquid crystal display panel, the following features can be enjoyed.

(1) It exhibits heat resistance and can be made into a thin film, and does not cause bubbles or delamination accidents even if it is affected by heat after being assembled as a panel for a liquid crystal display device.

(2) Liquid crystal resistance, organic chemical resistance, moisture resistance, heat resistance,
Improved light resistance.

(3) It has become possible to make panels ultra-thin, resulting in wider viewing angles, clearer displays, and lighter weight, and it has also become possible to manufacture larger display panels.

When measuring the R value, use a Senarmont compensator (manufactured by Nippon Geikagaku Co., Ltd.) equipped with a polarizing microscope.
was used, and a sodium lamp was used as the light source.

Next, examples of the present invention will be shown.

Example 1 Polysulfone resin having the following structural formula [manufactured by Nissan Chemical Industries, Ltd.: 10] was added to dimethylformamide (100 parts).
Department] was added and stirred while heating to 80°C to dissolve. This solution was cast onto a glass plate and allowed to stand in an atmosphere at 90°C for about 5 hours to obtain a uniform transparent film with a thickness of 83μ. The heat distortion temperature of this film is 175℃, and the R value is
It was 6 mμ. On the other hand, methyl ethyl ketone (50
phenoxy resin (manufactured by Union Carbide Co., Ltd.) in a mixed solution of Cellsolve Acetate (50 parts) and Cellsolve Acetate (50 parts).
Bakelite phenoxy resin (40 parts) was added and dissolved with stirring, and then a polyisocyanate resin solution (manufactured by Nippon Polyurethane Co., Ltd., Coronate L: ethyl acetate solution solid content 70%, 50 parts) was added and dissolved with stirring. This solution was applied to a thickness of 20 μm on both sides of the polysulfone film, dried in an atmosphere of 70° C. for about 1 hour, and then heat-treated at 150° C. for 30 minutes to obtain a transparent film with a thickness of 98 μm. The heat distortion temperature of the obtained film is
At 175°C, the R value was 8 mμ, the visible light transmittance was 87%, and it was stable against organic chemicals such as toluene and cyclohexanone and had excellent flexibility.

Example 2 1,1,2,2 tetrachloroethane (120 parts)
Polyarylate resin with the following structural formula [Unitika Co., Ltd.]
U polymer: 15 parts] was added and stirred while heating to 100°C to dissolve. This solution was cast onto a glass plate and allowed to stand in an atmosphere at 90°C for about 6 hours to obtain a uniform transparent film (U polymer film) with a thickness of 90μ.

The heat distortion temperature of this film was 170°C and the R value was 2 mμ.

Impact strength: 21Kg・cm/cm Tensile strength: 740Kg/cm ² Meanwhile, phenoxy resin (manufactured by Union Carbide, Bakelite phenoxy) was added to a mixture of methyl ethyl ketone (60 parts) and cellusolve acetate (40 parts).
Resin: 35 parts) and stir to dissolve, then polyisocyanate resin solution (manufactured by Nippon Polyurethane Co., Ltd.,
Coronate L: Ethyl acetate solution, solid content 70%, 40
part) was added and dissolved with stirring. This solution was applied to a thickness of 16 μm on one side of the above-mentioned U polymer film (90 μm thick), dried in an atmosphere of 70°C for about 2 hours, and then heated at 160°C.
A 95μ transparent film was obtained by heat treatment for 20 minutes. The heat distortion temperature of the obtained film was 170℃, and the R value was
2mμ, visible light transmittance is 89%, impact strength is 21Kg.
cm/cm, the tensile strength was 740 Kg/ ^cm2 , and a firm film was obtained that was stable in toluene and cyclohexanone.

Example 3 Polysulfone resin (Udel) 20 manufactured by UCC
g to 100ml of 1,1,2,2-tetrachloroethane
and stirred while heating to 80°C to obtain a solution. This solution was cast onto a glass plate and dried at 80 to 100°C to obtain a 120μ transparent film. When the optical isotropy of the film was measured, the R value was 5 mμ and the heat distortion temperature was 173°C. Meanwhile, 40 parts of pentaerythritol tetraacrylate, methyl cellosolve
60 parts and 0.02 part of benzoin ethyl ether were added to make a homogeneous solution. The viscosity of this solution was 4CPS.
The system is placed in a nitrogen atmosphere and is stirred vigorously.
Ultraviolet rays were irradiated for 1 minute using a 400W high-pressure mercury lamp, and stirring was continued for 18 minutes, after which air was introduced to stop the reaction. The viscosity of the solution at this time was 10 CPS.
Next, 3% by weight of benzoyl peroxide based on pentaerythritol tetraacrylate was added to this solution to prepare a coating composition.

The coating composition solution prepared in this manner was applied (10μ) onto the above polysulfone film using an applicator, dried and then heat treated at 130°C for 7 minutes to obtain the desired surface-cured polysulfone film. The physical properties of the obtained film were a heat distortion temperature of 174°C, an R value of 5 mμ, a light transmittance of 82%, and it was stable in organic solvents such as toluene and cyclohexquinone.

Example 4 The following surface hardening agent solution was applied to one side of a melt-formed polyether sulfone film (thickness: 80μ, retardation value: 12mμ) using an applicator (15μ), and after drying, it was heat-treated at 130°C for 7 minutes. A surface-cured polyether sulfone film was obtained.

Pentaerythritol tetraacrylate
40 parts by weight Benzoin ethyl ether 0.02 parts by weight Methyl cellosolve 60 parts by weight Benzoyl peroxide 15 parts by weight The heat distortion temperature of the obtained film was 160°C, the R value was 15 mμ, the average visible light transmittance was 85%, and the Izot impact strength was It had a critical bending width of 3.5 kg/cm/cm, a swelling degree of 0.1% due to chemicals, and was optically isotropic and stiff, with excellent chemical stability and flexibility.

Example 5 15 g of polyether sulfone manufactured by ICI was mixed with 120 g of methylene chloride/chloroform (50/50 weight ratio) mixture.
ml, cast on a glass plate, and dried to obtain a transparent film with a film thickness of 100 μm. When the optical isotropy of the film was measured, the R value was 2 mμ and the heat distortion temperature was 170°C. On the other hand, isobutanol
22.5 parts and 0.202 parts of water were placed in a 100 ml beaker and mixed uniformly. To this, 1.25 parts of N-(trimethoxysilylpropyl)ethylenediamine was gradually added and dissolved with stirring. Next, 1.25 parts of γ-glycidoxypropyltrimethoxysilane was gradually added while stirring. Stirring was stopped when the entire solution became homogeneous, and the container was transferred to a glass container with a stopper, tightly sealed, and heated at 50°C. After aging for a day and night and cooling to room temperature, the whole was diluted with 6 ml of dipropylene glycol monomethyl ether to prepare a coating composition.

The thus prepared coating composition solution was applied to the above polyether sulfone film using an applicator and dried, followed by heat treatment at 135°C for 30 minutes to obtain a surface hardened polyether sulfone film with a coating layer of 4 μm. This film had a transmittance of 87%, an R value of 2 mμ, was optically isotropic, and had good chemical resistance and liquid crystal resistance.

Example 6 84.8 parts of hexakismethoxymethylolmelamine and 52.5 parts of 1,4-butanediol were reacted to form a prepolymer, and further ethylene glycol
1.38 parts were added and dissolved in 13 parts of ethyl cellosolve. A curing liquid was prepared by adding 3.9 parts of para-toluenesulfonic acid as a catalyst. A polyether sulfone film (film thickness:
180μ, R value 12mμ) After coating and drying, heat treatment was performed at 130℃ for 10 minutes to form a hardened layer of 5μ to obtain a transparent film with good optical isotropy, heat resistance, chemical resistance, and liquid crystal resistance. Ta.

Example 7 12 g of Union Carbide phenoxy resin (Bakelite) was dissolved in 50 ml of dioxane, then cooled to room temperature, and 2 g of tolylene diisocyanate and 50 ml of methyl ethyl ketone were added and stirred to obtain a homogeneous solution. This solution was cast onto a polyester film, dried, and then heat-treated at 120° C. for 10 minutes to obtain a transparent film with a thickness of 150 μm. When the optical isotropy of the film was measured, the R value was
It was 4 mμ. Next, a cured layer was formed on the film in the same manner as in Example 3 to obtain a transparent film with good heat resistance, chemical resistance, and liquid crystal resistance.

Example 8 A transparent film was obtained in the same manner as in Example 3 using a polyacrylonitrile film (film thickness 150μ, R value 3mμ) cast by dry method.

Example 9 1,1,2,2 tetrachloroethane (120 parts)
Polyarylate resin [Unitika Co., Ltd. U Polymer:
15 parts] and heated to 100°C with stirring to dissolve. This solution was cast onto a glass plate and placed in an atmosphere of 90℃ for about 6 hours.
A uniform transparent film (U polymer film) with a thickness of 90 μm was obtained by allowing it to stand for a period of time. The heat distortion temperature of this film was 170°C, and the R value was 2 mμ.

Impact strength: 21Kg/cm/cm Tensile strength: 740Kg/cm ² Pentaerythritol tetraacrylate
40 parts of methyl cellosolve, and 0.02 parts of benzoin ethyl ether were added to make a homogeneous solution. The viscosity of this solution was 4CPS. The system was placed in a nitrogen atmosphere, and ultraviolet rays were irradiated with a 400W high-pressure mercury lamp for 1 minute while stirring vigorously. After stirring was continued for 18 minutes, air was introduced to stop the reaction. The viscosity of the solution at this time was 10 CPS. Next, 3% by weight of benzoyl peroxide based on pentaerythritol tetraacrylate was added to this solution to prepare a coating composition.

The coating composition solution prepared in this manner was applied (10μ) onto the above U polymer film using an applicator, and after drying, it was heat-treated at 130°C for 7 minutes to cure the surface of U with a heat distortion temperature of 170°C and an R value of 2mμ.
A polymer film was obtained.

Claims (1)

[Claims] 1 Made of synthetic resin material with a heat distortion temperature of 80℃ or higher, and a retardation value of 30mμ or lower,
A transparent film or sheet that is protected by a cured film with a heat distortion temperature of 80°C or higher.