KR101102694B1 - Process for Producing Protective Film for Polarizing Plate - Google Patents

Abstract

An object of the present invention is to provide an inexpensive film which is an electrically conductive film having an optical property such as transparency, which is not a problem even if disposed inside the LCD, and has an antistatic or electromagnetic wave blocking function. In addition, an object of the present invention is a polymer film having a conductive polymer attached to a surface thereof, wherein the conductive polymer is polythiophene or a derivative thereof, and the polymer film comprises an acetylcellulose-based or norbornene-based material, and the thickness of the conductive polymer layer It is 3 micrometers or less, visible light transmittance is 78% or more, and surface specific resistance is 10 <^3> ohm / square-10 <^12> ohm / square, It is providing the polymer film by which the electrically conductive process was performed.

Conductive polymer film, surface resistivity, hard coating, polarizer.

Description

Process for Producing Protective Film for Polarizing Plate

The present invention relates to a polymer film having a conductive polymer attached to a surface thereof, and in detail, the conductive polymer is a polythiophene or a derivative thereof, and the polymer film comprises an acetyl cellulose-based or norbornene-based material, The present invention relates to a polymer film having a thickness of 3 μm or less, a visible light transmittance of 78% or more, and a surface resistivity of 10 ³ to 10 ¹² Ω / □, which is used for a display such as a liquid crystal display (LCD), and is used for preventing static electricity and blocking electromagnetic waves. It relates to a highly transparent conductive treated polymer film having a function, and is particularly advantageously used for a protective film of a polarizing plate.

The polarizing plate stretches a polyvinyl alcohol (PVA) film, attaches a film containing triacetyl cellulose (TAC) to both sides of the PVA on both sides of the polarizing film to which iodine, dyes, etc. are attached and fixed, It is structured to prevent the characteristic change by reinforcement and absorption. TAC has been used as a protective film of such a polarizing film because it has excellent transparency, small birefringence, and easy adhesion to PVA. In recent years, as the size of liquid crystal displays increases, the size of the dimensional change due to the absorbency also becomes a problem even in a TAC film. It is considered as an alternative material for TAC.

On the other hand, in displays such as LCDs, CRTs, ELs, and PDPs, since electromagnetic waves generated by themselves adversely affect the human body, it is necessary to block the electromagnetic waves. In addition, in the case of installing the film having the electromagnetic wave shielding function inside and outside of the display, it is necessary to have excellent transparency, small birefringence, high strength, high heat resistance, and low absorbency. A film having a function needed to be developed.

In order to block the electromagnetic waves, a conductive material can be disposed on the front surface of the display. Generally, as a highly transparent conductive material, one having ITO or the like attached to the polymer film by sputtering or vapor deposition is used. Since the productivity of itself is bad and the material itself is expensive, there is a problem that the film to which conductivity is provided becomes very expensive. In addition, ITO tends to be colored yellow, and this coloration also becomes a problem as the coloration of LCDs is performed.

Moreover, when it is arrange | positioned in displays, such as LCD, EL, and PDP, dust adhesion by static electricity also becomes a big problem and it was also required to have an antistatic function.

Polyaniline derivatives, polypyrrole derivatives, and polythiophene derivatives are well known as conductive polymer materials. To obtain high resistance, polyaniline is colored green and polypyrrole is colored gray.

SUMMARY OF THE INVENTION An object of the present invention is to solve such a problem of the prior art and to provide a film which is inexpensive even when disposed on a display such as an LCD, and which is a conductive film having an antistatic or electromagnetic wave blocking function and which is inexpensive.

That is, the present invention is a polymer film having a conductive polymer attached to a surface thereof, wherein the conductive polymer film has a visible light transmittance of 78% or more and a surface resistivity of 10 ³ to 10 ¹² Ω / square, and is a polyti as a conductive polymer. It is easily achieved by using an offenic material, controlling the thickness of the conductive polymer layer to 3 µm or less, and using an acetylcellulose-based material or a norbornene-based material as the polymer film material.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail.

The conductive polymer used in the present invention is a homopolymer or copolymer obtained by polymerizing thiophene and / or thiophene derivatives. The conductive polymer is a homopolymer or copolymer having a unit represented by the following general formulas (1), (2), (3) and (or 4) as a polymer component, and may be a copolymer containing a small amount of other polymerized units as a copolymerization component. .                     

In formula, m is 1-4.

In Chemical Formulas 1 and 2, R ¹ and R ² each represent a hydrogen atom, an aliphatic hydrocarbon group having 1 to 20 carbon atoms, an alicyclic hydrocarbon group or an aromatic hydrocarbon group, a hydroxyl group, a group having a hydroxyl group at the terminal, an alkoxy group, and a terminal Group having alkoxy group, carboxyl group, carboxyl group, group having carboxyl group at the terminal, group having carboxyl group at the terminal, ester group, group having ester group at the terminal, sulfonic acid group, group having sulfonic acid group at the terminal, sulfonyl group , A group having a sulfonyl group at the terminal, a sulfinyl group, a group having a sulfinyl group at the terminal, an acyl group, a group having an acyl group at the terminal, an amino group, a group having an amino group at the terminal, and some or all of the hydrogen atoms of the amino group are substituted A group having a terminal at which some or all of the hydrogen atoms of the amino group are substituted, a group having a carbamoyl group at the terminal, and some or all of the hydrogen atoms of the carbamoyl group Hwandoen group, a group having a carbamoyl group of the group having a group in which some or all of the hydrogen atoms substituted at the terminal thereof, a halogen group, a phosphate group, a phosphate group having a group at the terminal, the terminal oxirane group or an oxirane group.

In the above formulas (2) and (4), Y ⁻ is an element or compound having an anion, and halogen ions, sulfonic acid ions, carboxylic acid ions and the like are exemplified, and polymers having these anions are shown.

To the conductive polymers of such thiophenes, a dopant may be added, for example, 0.1 to 500 parts by weight based on 100 parts by weight of the conductive polymer in order to further increase the conductivity. Examples of the dopant include LiCl, R ³ COOLi (wherein R ³ is a saturated hydrocarbon group having 1 to 30 carbon atoms), R ³ SO ₃ Li, R ³ COONa, R ³ SO ₃ Na, R ³ COOK, R ³ SO ₃ K , Tetraethylammonium, I ₂ , BF ₃ Na, BF ₄ Na, HClO ₄ , CF ₃ SO ₃ H, FeCl ₃ , tetracyanoquinoline, Na ₂ B ₁₀ Cl ₁₀ , phthalocyanine, porphyrin, glutamic acid, alkylsulfonates, And polystyrene sulfonic acid alkali salt copolymers, polystyrene sulfonic acid anions, styrene sulfonic acid and styrene sulfonic acid anion copolymers, and the like.

In this invention, in order to make adhesiveness of a polymer film and a conductive polymer more favorable, binder resin can be mix | blended with a conductive polymer. The binder resin can be appropriately selected from those having excellent adhesiveness with respect to the type of polymer film, and is not particularly limited, but may be polyester resin, acrylic resin, acrylic modified polyester resin, urethane resin, vinyl acetate type, vinyl chloride type , Polyvinyl alcohol, polyethylene vinyl acetate, organic silicate and the like. Of course, two or more types of binders can also be mixed and used.

The conductive polymer layer according to the present invention has a surface specific resistivity of 10 ³ to 10, which is formed by applying an aqueous coating liquid containing a conductive polymer obtained by polymerizing a thiophene and / or a thiophene derivative onto a polymer film, drying and curing. It is a coating film of 10 ¹² Ω / □. Particularly preferably from 10 ⁴ to 10 ⁸ Ω / □ is. If the surface resistivity is less than 10 ³ Ω / □, it is necessary to thicken the coating layer, or the coating film is receded because of the insufficient amount of the binder to be described later. If the surface resistivity is higher than 10 ¹² Ω / □, the antistatic effect and the electromagnetic shielding effect are obtained. Lack.

The conductive polymer layer formed by the coating method is a composition in which the conductive polymer is 1 to 95% by weight, preferably 2 to 70% by weight, and the binder resin is 5 to 99% by weight, preferably 30 to 98% by weight. It is preferable to apply | coat the aqueous coating liquid containing to a polymeric film, and to dry and harden | cure.

When the ratio of the conductive polymer and the binder resin is in the above range, the adhesion between the polymer film and the conductive polymer is good, the antistatic effect is excellent, and the adhesion and the shaping resistance are good.

The composition of the conductive polymer and the binder resin can be obtained by a commonly used mixing method, but the method of coating the conductive polymer on the surface of the particulate binder resin or chemically bonding the functional groups present in the conductive polymer and the functional groups present in the binder resin. It can also be applied to the method.

As a component of a conductive polymer layer, an epoxy resin, a vinyl resin, a polyether resin, a water-soluble resin, etc. can be mix | blended arbitrarily for the purpose of adjusting adhesiveness, solvent resistance, water resistance, etc. In addition, in order to improve the slip resistance and blocking resistance of the coating film, inorganic and organic fine particles having an average particle diameter of about 0.01 to 20 µm may be contained as a lubricant at a ratio of 0.001 to 5% by weight.

As such fine particles, inorganic fine particles such as silica, alumina, titanium oxide, carbon black, kaolin, calcium carbonate, polystyrene resin, crosslinked polystyrene resin, acrylic resin, crosslinked acrylic resin, melamine resin, silicone resin, fluorine resin, urea resin, benzogua Organic fine particles, such as a namin resin, can be illustrated. The organic fine particles may be thermoplastic resins or thermosetting resins as long as they are resins capable of maintaining the state of the fine particles to some extent in the coating film. Moreover, in order to improve electroconductivity, you may mix an electrically conductive filler, for example, tin oxide type microparticles | fine-particles and indium oxide type microparticles | fine-particles.                     

In addition to the fine particles, a surfactant, an antioxidant, a colorant, a pigment, a fluorescent brightener, a plasticizer, a crosslinking material, an organic slip agent, an ultraviolet absorber, an antistatic agent, and the like may be added as necessary.

In the present invention, a conductive polymer layer is formed by using the conductive polymer and an aqueous coating solution containing a binder, a dopant, and other additives as necessary, and the solid content concentration of the aqueous coating solution is usually used in an amount of 0.1 to 30% by weight. 1-20 weight% is preferable. If solid content concentration exists in such a range, the viscosity of aqueous coating liquid will become suitable for application | coating. The aqueous coating solution can be used in any form such as an aqueous solution, an aqueous dispersion, an emulsion, and a solvent soluble in water such as alcohols such as methanol, ethanol, isopropyl alcohol, ethylene glycol, and ketones such as acetone and methyl ethyl ketone. It is also possible to increase the evaporation rate of the solvent by adding. In particular, alcohols are preferably used in view of high miscibility with water and good smoothness. Moreover, a small amount may also be contained in the range in which other solvent does not become a problem. In the present invention, an oxidizing agent is applied to the surface of the substrate on which the conductive polymer layer is formed in units of several micrometers, and the monomer (monomer) is brought into contact with the oxidant coating film in a gaseous state to advance polymerization to form a conductive polymer film on the substrate. have.

In the present invention, the conductive polymer layer is formed by applying the coating liquid to a transparent polymer film. Since the polymer film coated with the conductive polymer layer is used as an optical film, and in particular, it is used as a protective film of a polarizing plate, the transmittance of visible light and birefringence are mentioned as important characteristics in the polymer film used. The higher the transmittance of visible light is, the better it is, and is 78% or more, preferably 82% or more, and particularly preferably 85% or more. The smaller the birefringence is, the better it is. The thickness is preferably 100 nm or less, preferably 50 nm or less, and a polymer film having both of these properties is preferably used.

As such a polymer film, an acetyl cellulose-based film and a norbornene-based film are used in terms of properties such as visible light transmittance, birefringence and yellow colorability.

As an acetyl cellulose type film, the cellulose triacetate film (TAC film) which used cellulose fiber as a raw material, the cellulose diacetate film, these modified films, etc. are mentioned. This film is usually obtained by applying a solution obtained by dissolving cellulose fibers in a suitable solvent such as methylene chloride on a stainless belt or a suitable polymer film, and then removing the solvent to dryness.

The norbornene-based film preferably used in the present invention is not particularly limited as long as it is a polymer obtained from one or a plurality of polymerizable monomers having a norbornene structure. For example, a polymer can be obtained by ring-opening-polymerizing the monomers containing a norbornene structure, and then hydrogenating some or all of the double bond which remained by the hydrogenation catalyst. Specifically, Nippon Xeon Kabushiki Kaisha is a trade name manufactured by the method disclosed in Japanese Patent Laid-Open No. 63-218726, Japanese Patent Laid-Open No. 5-25220, Japanese Patent Laid-Open No. 9-183832 and the like. And Aton of JSR Kabushiki Kaisha manufactured by the methods illustrated in Zeonex, Zeonoa, Japanese Patent Application Laid-Open No. Hei 5-97978 and Japanese Patent Application Laid-open No. Hei 1-240517 and the like.                     

In addition, there are also polymers obtained by addition polymerization of a monomer group in which a monomer having a norbornene structure and some other monomers having a double bond are combined by a known method, for example, Japanese Patent Application Laid-Open No. 6-107735, Japanese Patent Mitsui Chemical Co., Ltd. manufactured by the method disclosed in Japanese Patent Laid-Open No. 62-252406 and Japanese Patent Laid-Open No. Hei 8-259629 and the like, trade name Apel, Topas commercialized by Hexest, and the like.

The method of manufacturing a film from the polymer obtained in this way can apply a well-known method. For example, the polymer is dissolved in a solvent capable of dissolving the polymer well, specifically, a halogen-based solvent such as methylene chloride, an aromatic or alicyclic organic solvent, and a polymer film such as stainless steel or a belt or polyester. It can manufacture by what is called the casting method obtained by apply | coating a polymer solution to and removing a solvent and drying. Moreover, it can also manufacture by the so-called extrusion method obtained by melt | dissolving a polymer by heat and cooling after discharge on a metal belt.

Moreover, when manufacturing an acetyl cellulose type film and norbornene type film, various additives, such as antioxidant, an ultraviolet absorber, an ultraviolet stabilizer, a coloring agent, a lubricant, an antistatic agent, various pigments and dyes, fibers, a dispersing agent, etc. are contained in these polymers as needed. Can be added to prepare a film. When using as a protective film of a polarizing plate, the film which contained antioxidant, an ultraviolet absorber, and an ultraviolet stabilizer rather is used preferably.

The film thus obtained may be coated on the surface for various purposes. For example, in order to prevent surface scratches, those coated with acrylic, urethane, and urethane acrylic UV curable and thermosetting hard coating agents, epoxy hard coating agents, silicone hard coating agents and the like may be used. Further, this was to contain the fine particles such as Si0 ₂ and alumina in the coated hard coating, reduce the gloss so-called anti-can be also the article Laird (anti-glared) hard coating. When using as a protective film of a polarizing plate, what apply | coated the said hard coating and an anti-glare hard coating agent is used more preferably.

As a coating method of the coating liquid to the said polymer film, well-known arbitrary coating methods can be applied. For example, roll coating method, gravure coating method, screen printing method, offset printing method, micro gravure coating method, reverse coating method, roll brush method, spray coating method, air knife coating method, impregnation method and curtain coating method, etc. It may be applied alone or in combination.

In the present invention, the conductive polymer layer has a thickness of 0.005 to 3 µm, preferably 0.01 to 1 µm, and more preferably 0.02 to 0.5 µm. If the thickness is too thin, a sufficient antistatic effect may not be obtained. If the thickness is too thick, cracks may occur in the coating film or the blocking resistance may decrease. The conductive polymer layer can be applied to both sides of the polymer film or can be applied to one side.

Thus, on the polymer film in which the conductive polymer layer was formed, the above-mentioned hard coating agent and anti-glare hard coating can also be performed. Moreover, various well-known coatings, for example, antireflection coating, antifouling coating, coating of the pressure-sensitive adhesive layer, or the like may be applied according to the purpose. In the case where the conductive polymer layer is formed on one side, hard coating, anti-glare hard coating, antireflection coating, antifouling coating, coating of the pressure-sensitive adhesive layer and the like can be performed on the opposite side according to the purpose. Moreover, these coatings can also be combined in various ways according to the objective.

Although two polarizing plates are normally arrange | positioned before and after liquid crystal of LCD, although the film of this invention can also be used as a protective film of all four polarizing plates of two sheets, it can also be made into three pieces according to the objective, and can also be used by two pieces or one piece. have. In the case of using a plurality of sheets, the respective resistance values do not need to be the same, and the type of the polymer film can be appropriately selected according to the purpose. From the viewpoint of the electromagnetic wave shielding function, it is preferable to use the outermost protective film from the viewpoint of the effect and cost.

<Examples>

In the following, the present invention will be described in more detail.

&Lt; Example 1 >

20 g of a conductive polymer doped with 30 parts by weight of a copolymer of polystyrenesulfonic acid ion and polystyrenesulfonic acid in a molar ratio of 1: 1 by 16 parts by weight of deoxyethylene polythiophene (Baytron PH of Bayer), an acrylic resin, a urethane resin, Aqueous coating solution 1 containing 100 g of polyvinyl alcohol mixed at a weight ratio of 1: 1: 1 and 5 g of polyoxyethylene nonylphenyl ether as a nonionic surfactant in 1 kg of water containing 20% by weight of isopropyl alcohol. Got. This was applied to a triacetyl cellulose film (TAC film) having a thickness of 80 µm with a gravure coater and dried at 100 ° C. The thickness of the conductive polymer layer was 0.11 μm. The properties of this film are shown in Table 1. Compared with Comparative Example 1, which showed a difference by not applying the conductive polymer described below, the surface resistivity was 10 ¹⁴ Ω / □ or more, but the resistance was lowered to 8 × 10 ⁵ Ω / □ by application, resulting in higher electrical conductivity. Nevertheless, it was found that the total light transmittance and the birefringence hardly deteriorated, and the yellowness became small on the contrary. Even if disposed inside the LCD, especially when used as a protective film of the polarizing plate, it does not adversely affect the optical characteristics, but rather the chromaticity is improved, showing that the electromagnetic wave blocking function and the antistatic function can be added.

Comparative Example 1

In Example 1, the characteristic value of the TAC film which did not apply the conductive polymer was measured, and is shown in Table 1.

<Example 2>

The aqueous coating liquid 1 used in Example 1 was used, and the haze value was 27.1% and the glossiness of the 60 degree angle was apply | coated and hardened | cured after apply | coating this which disperse | distributed the micro silica to the 80-micrometer-thick TAC film in the ultraviolet-curable acryl-type hard coating agent previously. An anti-glare film was used so as to be 34.3%, and a conductive polymer was applied to the surface in the same manner as in Example 1. The thickness of the conductive polymer layer was 0.12 mu m. The properties of this film are shown in Table 2. Comparative Example 2, which will be described later, shows the characteristic value when the conductive polymer is not applied. On the other hand, the resistivity decreases from 10 ¹⁴ ? /? To 7 × 10 ⁵ ? /? And birefringence hardly changed, while yellowness was rather improved. Moreover, it turned out that haze value and glossiness hardly change even if it apply | coats on an anti-glare-treated layer. From this result, even if the anti-glared TAC film coated with the conductive polymer of the present invention is disposed inside the LCD, the anti-glare treatment effect can be maintained, and the electromagnetic properties are not adversely affected by the optical properties. It can be seen that the antistatic function can be given, and the yellowness is improved on the contrary.

Comparative Example 2

In Example 2, the characteristic values of the anti-glared TAC film which did not apply only the conductive polymer are shown in Table 2.

<Example 3>

In Example 1, the coating film was obtained likewise except having made the conductive polymer 10g. The thickness of the conductive polymer layer was 0.12 mu m. The properties of this film are shown in Table 1.

<Example 4>

An application film was obtained in the same manner as in Example 1 except that the thickness of the conductive polymer layer was 1.2 μm. The properties of this film are shown in Table 1.

Example 5                     

The same aqueous coating solution 1 as in Example 1 was applied to a 100 μm thick film (trade name Aton) containing a norbornene material of JSR. The thickness of the conductive polymer layer was 0.10 mu m. The properties of this film are shown in Table 1.

Comparative Example 3

In Example 5, the characteristic values of the film to which the aqueous coating liquid was not applied are shown in Table 1.

<Example 6>

It applied similarly to Example 5 except having used the 100-micrometer-thick atone film with which the film was anti-glare-treated similarly to Example 2. The thickness of the conductive polymer layer was 0.11 mu m. The properties of this film are shown in Table 2.

<Comparative Example 4>

In Example 6, the characteristic value of the film which does not apply the conductive polymer is shown in Table 2.

<Example 7>

The film was a film having a thickness of 100 μm (trade name Zeonoa) containing a norbornene material of Nippon Xeon Co., Ltd., Kaisha, and was the same as in Example 6 except that the anti-glare treatment was used in the same manner as in Example 6. An application film was obtained. The thickness of the conductive polymer layer was 0.12 μm, and the properties of the film are shown in Table 2.

Comparative Example 5

In Example 7, the characteristic value of the film which does not apply the conductive polymer is shown in Table 2.

Comparative Example 6

In Example 1, a polymer film was prepared in the same manner as in Example 1 except that polypyrrole was used instead of polythiophene as the conductive polymer. The properties of the obtained film are shown in Table 3.

&Lt; Comparative Example 7 &

In Example 1, a polymer film was prepared in the same manner as in Example 1 except that polyaniline was used instead of polythiophene as the conductive polymer. The properties of the obtained film are shown in Table 3.

According to the present invention, a polythiophene or a derivative thereof is attached to the surface as a conductive polymer, and includes an acetylcellulose-based or norbornene-based material, having a thickness of 3 µm, a visible light transmittance of 78% or more, and 10 ³ ? /? It is possible to provide a conductive polymer film exhibiting a surface intrinsic resistivity of 10 ¹² Ω / □, thereby achieving improved optical, antistatic and electromagnetic wave blocking properties.

Claims (11)

delete delete delete delete delete It is a manufacturing method of the protective film for polarizing plates which adhere | attached the conductive polymer on the surface of a polymer film, The conductive polymer is polythiophene or a derivative thereof, The polymer film is a norbornene-based film, The conductive polymer layer has a thickness of 3 μm or less, visible light transmittance of 78% or more, and surface resistivity of 10 ⁴ to 10 ⁸ Ω / □, Forming a conductive polymer layer on the surface of the norbornene-based film by an aqueous coating liquid containing polythiophene or a derivative thereof as the conductive polymer, the solid content concentration of the aqueous coating liquid being 1 to 20% by weight, The yellowness of the conductive polymer film is made smaller than the yellowness of a norbornene-based film by forming a conductive polymer layer, The manufacturing method of the protective film for polarizing plates characterized by the above-mentioned. The manufacturing method of the protective film for polarizing plates of Claim 6 in which an aqueous coating liquid further contains binder resin. The manufacturing method of the protective film for polarizing plates of Claim 6 in which an aqueous coating liquid further contains a dopant. delete The manufacturing method of the protective film for polarizing plates of Claim 6 in which an aqueous coating liquid contains the solvent soluble in water. The manufacturing method of the protective film for polarizing plates of Claim 6 with which the electrically conductive polymer film is further hard-coated.