KR20130082350A - Conductive polymer membrane using a coating composition of conductive polymer comprising low refractive index material - Google Patents

Abstract

PURPOSE: A conductive polymer membrane using a conductive polymer coating composition with a low refraction compound is provided to be employed as an electromagnetic wave shielding layer like an upper and a lower electrode film for a touch panel, an inorganic electroluminescence device (EL) electrode film for a mobile phone etc. due to its low surface resistance, ultra high transparency, strong adhesive force, durability and low reflectance. CONSTITUTION: A conductive polymer membrane is produced by coating a polythiophene-based conductive polymer aqueous solution and a conductive polymer coating composition including a low refraction compound with 1.3-1.5 of the refractive index on a substrate and drying the substrate. The conductive polymer membrane has the following characteristics: surface resistance of 100-1000 Ω/m^2, permeability of more than 98%, haze value of 3% or less and reflectivity of less than 5.5%.

Description

A conductive polymer membrane using a conductive polymer coating composition containing a low refractive index compound TECHNICAL FIELD

The present invention relates to a polymer membrane using a conductive polymer coating composition comprising a low refractive compound.

Currently, polyaniline (Polyaniline, PAN), polypyrrol (PPy), and polythiophene (PT) are widely used as conductive polymer compounds. They are easy to polymerize, have very good conductivity, thermal stability and oxidation stability.

By applying the electrical properties of these conductive polymer compounds, the possibility of use in various applications, such as the electrode of the secondary battery, electromagnetic shielding material, flexible electrode, antistatic material, anti-corrosion coating material has been proposed, but difficult processing, thermal and atmospheric Due to problems of stability, environmental resistance, and price, it is not actively commercialized.

However, recently, as the dust adhesion prevention and antistatic coating materials have attracted attention, the conductive polymer compounds have been attracting attention as the electromagnetic wave shielding coating material of various electronic devices by strengthening the standard for electromagnetic shielding.

In particular, the conductive polymer is attracting attention as a conductive coating on the glass surface of the CRT, as described in US Patent Nos. 5,035,926 and 5,391,472, polyethylene dioxythiophene (PEDT) is a polythiophene-based conductive polymer Since it is known. Such conductive polymers exhibit excellent transparency compared to polyaniline-based and polypyrrole-based as well as other polythiophene-based conductive polymers.

Conventional polyethylenedioxythiophene is made of a coating solution capable of water dispersion using a high molecular acid salt such as polystyrene sulfonate as a doping material in order to improve conductivity, and is excellent in mixing and processing with alcohol solvents, and thus is excellent in CRT glass. It could be used as a coating material for various materials such as plastic film surface. A representative example of such a water-dispersible polyethylene dioxythiophene is Clevios P Co., Ltd., which is currently sold. However, the polyethylenedioxythiophene conductive polymer should be coated with a low concentration of polyethylenedioxythiophene in order to maintain high transparency of 95% or more even though it has excellent transparency. It is difficult to achieve surface resistance in the range of 100 to 1000 Ω / m 2.

As a related art, Korean Patent Publication No. 2000-10221 discloses a conductive polymer composition containing polyethylenedioxythiophene, an alcohol solvent, an amide solvent, a polyester resin binder, and the like. 66209 discloses a conductive light diffusing film coating composition containing polyethylenedioxythiophene, a solvent of alcohols, an amide solvent, a silane coupling agent, and the like. The composition has electrical properties in the range of 100 ~ 1000 Ω / ㎡ surface resistance, and gives high transparency, strong adhesion and durability, but recent display devices as well as higher transparency as well as external light such as sunlight or fluorescent light It demands more performance to prevent reflection while being reflected.

To this end, a low reflection film in which transparent layers of at least one metal oxide are laminated is used, but existing films have disadvantages of high production cost, low productivity, and low surface resistance that can be used for electrodes. .

Therefore, while the present inventors have been researching ways to solve the above-mentioned problems, by adding a low refractive compound to the conductive polymer solution, the present inventors can prepare a conductive polymer membrane having high conductivity, ultra high transparency, strong adhesion, strong durability and low reflectance. Confirmed that the present invention was completed.

Accordingly, it is an object of the present invention to provide a conductive polymer membrane having high conductivity, ultra high transparency, strong adhesion, strong durability and low reflectivity.

Another object of the present invention is to provide a conductive polymer coating composition used in the production of the polymer membrane.

In order to achieve the above object, the present invention is prepared by applying a conductive polymer coating composition comprising a polythiophene-based conductive polymer aqueous solution and a low refractive index compound having a refractive index of 1.3 to 1.5 on a substrate and then dried, the following characteristics Provided is a conductive polymer membrane having:

(1) surface resistance in the range of 100 to 1000 Ω / m 2;

(2) transmittance greater than 98%;

(3) Haze value of 3% or less; And

(4) reflectance less than 5.5%.

In order to achieve the above another object, the present invention (1) polythiophene-based conductive polymer aqueous solution; (2) low refractive compounds having a refractive index of 1.3 to 1.5; (3) alcohol-based organic solvents; (4) amide organic solvents; And (5) at least one binder selected from the group consisting of polyesters, polyurethanes, polyacrylic resins and alkoxy silanes.

The conductive polymer film prepared from the conductive polymer coating composition according to the present invention has excellent properties such as surface resistance, ultra high transparency, strong adhesion, strong durability and low reflectivity in the range of 100 to 1000 Ω / m 2, and thus a touch panel It can be applied as upper / lower electrode film for panel), inorganic electroluminescent device (EL) electrode film for mobile phone, transparent electrode film for display, electromagnetic wave shielding layer on TV CRT surface and computer monitor screen, and other glass, polycarbonate acrylic It can also be usefully used for plates, polyethylene terephthalate or cast polypropylene (CPP) film.

1 is a SEM photograph of the conductive polymer membrane prepared in Example 2.

In one embodiment, the present invention is prepared by applying a conductive polymer coating composition comprising a polythiophene-based conductive polymer aqueous solution and a low refractive compound having a refractive index of 1.3 to 1.5 on a substrate and then drying, Provided is a conductive polymer membrane having:

(1) surface resistance in the range of 100 to 1000 Ω / m 2;

(2) transmittance greater than 98%;

(3) Haze value of 3% or less; And

(4) reflectance less than 5.5%.

Examples of the substrate may be a substrate made of a transparent material, and preferably, glass, a cast polypropylene (CPP) film, a polyethylene terephthalate film, a polycarbonate, and an acrylic panel may be used.

The coating method of the coating composition of the present invention may be carried out by a method known in the art, for example, bar coating, roll coating, flow coating, dip coating or spin coating may be used, and the like. Drying can be carried out for 1 to 10 minutes at a temperature of 100 to 145 ℃. The conductive polymer film prepared by the coating and drying preferably has a thickness of 1 to 5 탆.

The present invention (1) polythiophene-based conductive polymer aqueous solution; (2) low refractive compounds having a refractive index of 1.3 to 1.5; (3) alcohol-based organic solvents; (4) amide organic solvents; And (5) at least one binder selected from the group consisting of polyesters, polyurethanes, polyacrylic resins and alkoxy silanes.

In one embodiment, the present invention (1) 10 to 70% by weight of a polythiophene-based conductive polymer aqueous solution; (2) 0.001 to 40% by weight of the low refractive compound having a refractive index of 1.3 to 1.5; (3) 10 to 75 wt% of an alcoholic organic solvent; (4) 1 to 10% by weight of an amide organic solvent; And (5) 0.1 to 5 wt% of any one or more binders selected from the group consisting of polyesters, polyurethanes, polyacrylic resins and alkoxy silanes.

In another embodiment, the present invention (1) 14 to 67% by weight aqueous polythiophene-based conductive polymer; (2) 0.005 to 35 weight percent of a low refractive compound; (3) 25 to 70 wt% of an alcoholic organic solvent; (4) 2 to 5% by weight of an amide organic solvent; And (5) 0.5 to 4 wt% of any one or more binders selected from the group consisting of polyesters, polyurethanes, polyacrylic resins and alkoxy silanes.

Hereinafter, the components used in the polymer coating composition of the present invention will be described in detail.

(One) Polythiophene  Conductive Polymer Solution

The polythiophene-based conductive polymer aqueous solution includes a polythiophene-based conductive polymer, and the polythiophene-based conductive polymer may be a polythiophene-based conductive polymer commonly known in the art. Preferably, the polythiophene-based conductive polymer may be polyethylene dioxythiophene (PEDT). More preferably, the polyethylenedioxythiophene may be doped with polystyrene sulfonate. The polyethylenedioxythiophene doped with the polystyrene sulfonate is well soluble in water and has excellent thermal and atmospheric stability.

The polythiophene-based conductive polymer aqueous solution may include polythiophene-based conductive polymer in an amount of 1 to 1.5% by weight. If the polythiophene-based conductive polymer is used in an aqueous solution of less than 1% by weight, there is a problem that the conductivity of the polymer membrane prepared therefrom is lowered, and when it exceeds 1.5% by weight, the dispersibility may be lowered.

The polythiophene-based conductive polymer aqueous solution may be used in an amount of 10 to 70% by weight based on the total coating composition. When used in less than 10% by weight it is difficult to realize high conductivity, when used in excess of 70% by weight may cause a problem that the transmittance decreases due to the increase of the conductive polymer with colorability. More preferably, the polythiophene-based conductive polymer aqueous solution may be used in an amount of 14 to 67% by weight.

(2) having a refractive index of 1.3 to 1.5 Low refractive  compound

The low refractive index compound having a refractive index of 1.3 to 1.5 serves to improve the anti-reflection performance by lowering the refractive index of the coating layer and increasing the scattering and diffraction effects by concaving the surface. As such, the conductive polymer film prepared from the conductive polymer coating composition including the low refractive compound has low reflectance, ultra high transparency, and strong durability.

The low refractive compound used in the present invention is characterized by having a refractive index of 1.3 to 1.5. If the refractive index is 1.3 or less, it does not exist. If the refractive index is 1.5 or more, the antireflection performance is not sufficient.

Examples of the low refractive compound include a silicon-based compound or an acryl-based compound, but is not limited thereto, and preferably, silica (SiO ₂ ) or polymethylmethacrylate (PMMA) yl Can be.

The low refractive compound is characterized in that the particle size ranges from 4 nm to 30 μm. If the particle size is less than 4 nm, there is no effect of improving transmittance, and if the particle size exceeds 30 μm, a haze may increase. More preferably, it may range from 5 nm to 20 μm.

The low refractive compound may be used in an amount of 0.001 to 40% by weight based on the total coating composition. If it is less than 0.001% by weight, there is no effect of improving transmittance, and if it exceeds 40% by weight, a problem may occur in that conductivity decreases. More preferably, it may be used in an amount of 0.005 to 35% by weight.

(3) Alcohol  Organic solvent

The alcohol-based organic solvent is used to improve the dispersibility of the conductive polymer solution. Examples of the alcoholic organic solvent include C ₁ to C ₄ alcohols or mixtures thereof. Preferably, methanol or ethanol may be used as a main solvent to improve the dispersibility of the PEDT conductive polymer.

The alcoholic organic solvent may be used in an amount of 10 to 75% by weight based on the total coating composition. If the amount of the alcohol-based organic solvent is less than 10% by weight, the coating film dispersibility is impaired and permeability is inhibited. When the amount of the organic solvent exceeds 75% by weight, the dispersibility is improved, but the conductivity is reduced, and aggregation may easily occur. More preferably, it may be used in an amount of 25 to 70% by weight.

(4) Amide  Organic solvent

The amide organic solvent partially serves to re-dissolve the polymer group of the polythiophene-based conductive polymer aqueous solution to improve connectivity and dispersibility between the polythiophene-based conductive polymers.

Examples of the amide organic solvent include a solvent having an amide group in the molecule, preferably formamide (FA), N-methylformamide (NMFA), N, N-dimethylformamide (DMF), acetamide ( AA), N-methylacetamide (NMAA), N-dimethylacetamide (DMA), N-methylpyrrolidone (NMP) or mixtures thereof. The conductivity can be increased even by using an amide solvent alone, but it is preferable to use a mixture of two or more amide solvents. The amide organic solvent may be used in an amount ranging from 1 to 10% by weight. If the amide solvent exceeds 10% by weight, high temperature firing is required in the coating process, and it causes interference with the conductivity of the polythiophene conductive polymer due to heat. There is a possibility of causing deformation. More preferably, it may be used in an amount of 2 to 5% by weight.

(5) binder

The binder serves to impart substrate adhesion and durability to the polythiophene-based conductive polymer membrane. Examples of such binders include alcohol soluble binders such as polyester, polyurethane, polyacrylic or alkoxy silanes. The binder may be used in the form of an aqueous solution to improve dispersibility. In addition, when coating on the polyethylene terephthalate film, it is preferable to use a polyester resin to improve the adhesion to the substrate. On the other hand, the alkoxy silane may be a trifunctional and tetrafunctional silane compound, preferably trimethoxysilane or tetraethoxysilane.

The binder may be used in an amount of 0.1 to 5% by weight based on the total coating composition. If the amount is less than 0.1% by weight, the adhesion to the substrate and the durability of the conductive film is poor, and when the amount exceeds 5% by weight, it may inhibit the increase in conductivity. Preferably, it may be used in an amount of 0.5 to 4% by weight.

(6) other ingredients

In addition to the components described above, the conductive polymer coating composition of the present invention may further include an additive for slipping and viscosity lowering to increase blocking prevention and slippage of the coated surface. Examples of the additives include silane and fluorine, but are not limited thereto. Preferably it may be EFKA 3288 (Ciba company) or FC 4430 (3M company). The additive may be used in an amount of 0.05 to 5 parts by weight based on 100 parts by weight of the conductive polymer solution composition.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the following Examples are only intended to illustrate the present invention and are not intended to limit the present invention.

Example  1 to 7 and Comparative example  1 to 5

Using the components and the content ranges shown in Table 1 below, while vigorously stirring the polythiophene-based polymer aqueous solution, alcohol solvent, low refractive compound (but Comparative Examples 1 and 2 are not used), amide organic A solvent and a binder were added sequentially and uniformly mixed for about 4 hours to prepare a conductive polymer coating solution.

The coating solution was coated on a polyethylene terephthalate film and dried in an oven at about 125 ° C. for about 5 minutes to prepare a polythiophene polymer membrane. The dried polymer membrane had a thickness of 5 μm or less.

Composition (g) Polythiophene Conductive Polymer Solution Low refractive compounds Alcohol organic solvent Amide series
menstruum Binder Example 1 Clevios p
(52) N10
(0.5) MeOH
(39.5) FA (3)
DMF (1) R-986 (4) Example 2 Clevios p
(24) 130
(12) EtOH
(58) NMP (3) TEOS (3) Example 3 Clevios p
(24) ST-40
(25) MeOH
(44) DMF (3)
NMAA (2) R-986 (2) Example 4 Clevios p
(48) SX series
(16) EtOH
(29) FA (1)
NMP (2) PET (aq) (4) Example 5 Clevios p
(37) ST-ZL
(25) MeOH
(33) FA (2)
NMP (1) TEOS (2) Example 6 Clevios p
(35) ST-20L
(32) EtOH
(29) NMP (1) R-986 (3) Example 7 Clevios p
(16) 190
(20) EtOH
(59) FA (1)
DMF (2) TEOS (2) Comparative Example 1 Clevios p
(48) - EtOH
(44) FA (2)
NMP (1) R-986 (5) Comparative Example 2 Clevios p
(35) - MeOH
(61) NMP (4) - Comparative Example 3 Clevios p
(48) 130
(0.0005) MeOH
(46.9995) DMF (3) TEOS (2) Comparative Example 4 Clevios p
(35) ST-ZL
(45) EtOH
(13) DMF (3)
NMAA (2) PET (aq) (2) Comparative Example 5 Clevios p
(12) ST-40
(60) MeOH
(24) DMF (1)
NMAA (2) TEOS (1) Clevios P: Polyethylenedioxythiophene (manufactured by H. Star Corporation), solid content concentration 1.0 to 1.5 wt%
MeOH; Methyl alcohol (available from Aldrich)
EtOH; Ethyl alcohol (Aldrich)
FA: Formamide (manufactured by Aldrich)
PET (aq): An aqueous solution having a solid content of polyethylene terephthalate of 20% (manufactured by SKC)
R-986: aqueous solution having a solid content of polyurethane of 25% (manufactured by DSM)
NMP: N-methylpyrrolidone (manufactured by Aldrich)
DMF: N, N-dimethylformamide (manufactured by Aldrich)
NMAA: N-methylacetamide (Aldrich)
TEOS: tetraethoxysilane (Aldrich)
ST-40: colloidal silica, size 10 ~ 20 nm (from Snowtex)
ST-20L: colloidal silica, size 40 ~ 50 nm (from Snowtex)
ST-ZL: colloidal silica, size 70 ~ 100 nm (from Snowtex)
130: spherical silica powder, size 2-4 μm (manufactured by SILNOS)
190: spherical silica powder, size 8-10 μm (manufactured by SILNOS)
N10: Spherical Silica Powder, Size 10 ~ 12 μm (SILNOS Corporation)
SX Series: aqueous solution with 25% acrylic solids, size 80 ~ 100 nm (JSR)

Experimental Example

1) Surface Resistance

The surface resistance of the polymer membranes prepared in Examples and Comparative Examples was measured by an ohm meta group (Loresta EP MCP-T360, Mitsubishi Chemical Corporation).

2) Transparency (Transmittance)

The polymer membranes prepared in Examples and Comparative Examples were irradiated with UV-Vis 550 nm (CM-3500d, Minolta) and evaluated as their transmittance. At this time, the transmittance of the transparent substrate was set to 100% and the transmittance after coating was expressed as a ratio.

3) reflectance

The polymer films prepared in Examples and Comparative Examples were irradiated with UV-visible light 550 nm (CM-3500d, Minolta) and evaluated as reflectance.

4) Haze value

The polymer membranes prepared in Examples and Comparative Examples were measured using an NDH 5000W hazemeter (Hazemeter; Nippon Denshoku) (initial haze value: 1% or less). The haze value of 3% or less was good, and 3% or more was marked as bad.

5) Adhesion

After taping 10 times with a taping tester, the change in surface resistance was evaluated relative to the tape (use tape: manufactured by Nitto). 50 Ω / m 2 or less was good, and 50 to 100 Ω / m 2 was normally indicated, and 100 Ω / m 2 or more was indicated as defective.

The physical properties of the polythiophene polymer membrane prepared above were measured in the same manner as above, and the results are shown in Table 2 below.

Properties Surface resistance
(Ω / ㎡) transparency
(%) reflectivity
(%) Haze value
(Initial: 0.5%) Adhesion Membrane uniformity Example 1 650 99.1 5 2.1 Good Good Example 2 600 98.7 4.1 1.4 Good Good Example 3 400 99.3 3.3 1.7 Good Good Example 4 380 99 4.5 2.5 Good Good Example 5 450 99.2 4.7 1.8 Good Good Example 6 400 98.9 3.8 2.7 Good Good Example 7 400 99 5.2 1.5 Good Good Comparative Example 1 600 98 8 1.9 Good Good Comparative Example 2 550 98 7.5 1.4 Bad Good Comparative Example 3 500 97 6.2 2 Good Good Comparative Example 4 1250 98 6.5 7 Good Good Comparative Example 5 1180 97 5.8 8.5 Good Good

As shown in Table 2, in Comparative Examples 1 and 2 without using the low refractive compound, the transparency (transmittance, transmittance) did not exceed 98%, indicating poor transparency. In addition, in the case of Comparative Example 3 using a small amount of the low refractive index compound at 0.1% by weight or less, it was found that it was difficult to achieve ultra high transparency as 97%. Moreover, in Comparative Examples 4 and 5, in which the low refractive compound was used in excess of 40% by weight, the surface resistance increased (conductivity decreased) and the haze value increased.

In contrast, the conductive polymer membranes (Examples 1 to 7) prepared using the coating composition of the present invention have ultra high transparency, and have low surface resistance (excellent conductivity), adhesion, durability, and film uniformity. Could.

Claims (14)

A conductive polymer coating composition comprising a polythiophene-based conductive polymer aqueous solution and a low refractive compound having a refractive index of 1.3 to 1.5 is applied to a substrate, and then dried. The conductive polymer membrane has the following characteristics:
(1) surface resistance in the range of 100 to 1000 Ω / m 2;
(2) transmittance greater than 98%;
(3) Haze value of 3% or less; And
(4) reflectance less than 5.5%.
The method of claim 1,
A conductive polymer film, characterized in that the substrate is glass, casting polypropylene (CPP) film, polyethylene terephthalate film, polycarbonate or acrylic panel.
The method of claim 1,
Conductive polymer membrane, characterized in that the drying is performed for 1 to 10 minutes at a temperature of 100 to 145 ℃.
The conductive polymer membrane of claim 1, wherein the conductive polymer membrane is 1 to 5 μm thick.
(1) polythiophene-based conductive polymer aqueous solution;
(2) low refractive compounds having a refractive index of 1.3 to 1.5;
(3) alcohol-based organic solvents;
(4) amide organic solvents; And
(5) at least one binder selected from the group consisting of polyesters, polyurethanes, polyacrylic resins and alkoxy silanes
Conductive polymer coating composition comprising a.
The method of claim 5,
(1) 10 to 70% by weight of an aqueous polythiophene-based conductive polymer solution;
(2) 0.001 to 40% by weight of the low refractive compound having a refractive index of 1.3 to 1.5;
(3) 10 to 75 wt% of an alcoholic organic solvent;
(4) 1 to 10% by weight of an amide organic solvent; And
(5) 0.1 to 5% by weight of at least one binder selected from the group consisting of polyesters, polyurethanes, polyacrylic resins and alkoxy silanes
Characterized in that it comprises a conductive polymer coating composition.
The method of claim 5,
(1) 14 to 67 wt% of a polythiophene-based conductive polymer aqueous solution;
(2) 0.005 to 35 weight percent of a low refractive compound;
(3) 25 to 70 wt% of an alcoholic organic solvent;
(4) 2 to 5% by weight of an amide organic solvent; And
(5) 0.5 to 4% by weight of at least one binder selected from the group consisting of polyesters, polyurethanes, polyacrylic resins and alkoxy silanes
Characterized in that it comprises a conductive polymer coating composition.
The method of claim 5,
Conductive polymer coating composition, characterized in that the polythiophene-based conductive polymer aqueous solution comprises a polythiophene-based conductive polymer in an amount of 1.0 to 1.5% by weight.
The method of claim 5,
The polythiophene-based conductive polymer is characterized in that the polystyrene sulfonate doped with polyethylene dioxythiophene, conductive polymer coating composition.
The method of claim 5,
The conductive polymer coating composition, characterized in that the particle size of the low refractive compound having a refractive index of 1.3 to 1.5 is in the range of 4 nm to 30 μm.
The method of claim 5,
The low refractive index compound having a refractive index of 1.3 to 1.5 is characterized in that the silica, conductive polymer coating composition.
The method of claim 5,
The conductive organic solvent is characterized in that the C ₁ to C ₄ alcohol or a mixture thereof, conductive polymer coating composition.
The method of claim 5,
The amide organic solvent is formamide (FA), N-methylformamide (NMFA), N, N-dimethylformamide (DMF), acetamide (AA), N-methylacetamide (NMAA), N-dimethyl A conductive polymer coating composition, characterized in that it is selected from the group consisting of acetamide (DMA), N-methylpyrrolidone (NMP), and mixtures thereof.
The method of claim 5,
The conductive polymer coating composition, characterized in that the slip and viscosity-lowering additive selected from the group consisting of silicone, fluorine and mixtures thereof is added in an amount of 0.05 to 5 parts by weight based on 100 parts by weight of the conductive polymer coating composition.

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