KR19990075175A - Polymer hard coating composition having transparency and conductivity combined with excellent surface hardness - Google Patents

Abstract

The present invention is to provide a polymer hard coating composition having a transparency and conductivity consisting of 20 to 50% by weight of the conductive polymer aqueous solution and 50 to 80% by weight of the silica sol solution.

When the composition solution of the present invention is coated on a transparent substrate such as glass or synthetic resin film, a polymer having transparency and conductivity having physical properties of 10 ¹ to 10 ⁵ Ω / □, transparency of 95 to 85%, and film hardness of 5 to 8H A hard coat film is obtained.

The composition of the present invention exhibits antistatic and electromagnetic shielding functions on transparent TV surface such as TV CRT screen, computer monitor screen surface, other glass, polycarbonate and acrylic plate, polyethylene terephthalate or CPP film which requires transparency. .

Description

Polymer Hard Coating Composition Having Transparency and Conductivity

The present invention relates to a polymer hard coating composition having transparency and conductivity and a method of manufacturing the same. More specifically, the present invention relates to a polymer hard coating composition having transparency and conductivity prepared by mixing a conductive polymer compound well dispersed in water and a silica sol obtained by doping with a polymer acid.

Currently, the most widely used conductive polymer compounds include polyaniline (PAN), polypyrrol (PPy), and polythiophene (PT). These compounds are easy to polymerize, and have excellent conductivity and thermal safety. And oxidative safety, and thus are widely studied. By applying the electrical properties of these conductive polymer compounds, it is proposed that it can be used in various applications such as electrodes of secondary batteries, electromagnetic shielding materials, flexible electrodes, antistatic materials, and corrosion-resistant coating materials, but difficult to process, thermal and atmospheric safety. Due to problems such as problems, price, etc., they are not actively commercialized.

However, in recent years, with the attention of dust adhesion preventing and antistatic coating materials, the standards for electromagnetic wave shielding have begun to attract attention as a coating material for electromagnetic wave shielding of various electronic devices. In particular, a transparent conductive coating material that can be coated on a transparent substrate such as a computer monitor screen or safety glasses or a TV CRT glass surface has been attracting attention, rather than a material having coloring, which is a problem of the existing metal-based electromagnetic shielding material.

As the conductive polymer coating material having excellent transparency began to attract attention, water-soluble polydiethylene dioxythiophene (PEDT) began to attract attention as described in US Pat. Nos. 5, 035, 926 and 5,391,472. .

However, a major disadvantage in using such a conventional PEDT-based conductive polymer as an electromagnetic shielding and antistatic coating material has been a disadvantage that the hardness of the film formed after coating on the surface of the material, such as synthetic resin, glass, metal. Therefore, there is a problem in practical use, such as easily falling off and scratching even a little contact.

In addition, when the coating film of the PEDT-based conductive polymer is thick, dark blue appears, which has a disadvantage in that the color of the coating material is damaged. Therefore, the film hardness problem becomes very important in this case because at least a thin coating is required where transparency is required.

These thin coatings require electromagnetic shielding and antistatic coatings that require transparency while maintaining transparency, mainly for computer and TV CRT glass surfaces or safety glasses surfaces, clean room walls in electronic factories, etc. Special purpose cast polypropylene (CPP), polyethylene terephthalate (PET) film surface coating, and the like.

When applying a conductive polymer compound to the glass surface, for example, computer screen, TV brown tube, polyethylene terephthalate (PET) and polypropylene (PP) surface of the synthetic resin film to impart electromagnetic shielding and antistatic function, After coating the conductive polymer compound alone or a mixture of the conductive polymer compound and the organic molecule and thermally cured, the coating film has a very low hardness, so that scratches and desorptions are easily caused by weak contact and impact from the outside, thereby limiting practicality. .

Another practical problem is that transparency is not secured unless the coating film is as thin as possible due to the colorability of the conductive polymer compound. The present inventors have made a long-term effort to produce a coating film having excellent hardness even if the coating as thin as possible to ensure the transparency, it is easily melted in a solvent to form a coating film excellent in workability and excellent hardness and transparency after coating, so that no scratch occurs easily It has come to provide a hard coating composition.

An object of the present invention is to provide a polymer hard coating composition having transparency and conductivity.

Still another object of the present invention is to provide a hard coat film obtained by coating a polymer hard coating composition having transparency and conductivity on a transparent substrate such as glass or a synthetic resin film.

The present invention is a conductive polymer solution consisting of a conductive polymer, a polymeric acid dopant and water 20 to 50% by weight, and a conductivity consisting of 50 to 80% by weight silica sol solution 10 ¹ to 10 ⁵ Ω / □, transparency 95 to 85% , A polymer hard coating composition having transparency and conductivity that maintains a film hardness of 5 to 8H.

The conductive polymer used in the present invention is aniline chloride, pyrrole or 3,4-ethyleneoxythiophene, and the polymer compound having transparency and conductivity obtained therefrom is polyaniline, polypyrrole or polydioxyethylenethiophene.

As the dopant of the conductive polymers used in the present invention, a polymer acid substituted with a sulfonic acid group is preferable, and examples thereof include polystyrene sulfonate, beta-naphthalene sulfonate formalin condensate (Egon Industries Co., Ltd.) or melamine sulfonate formalin. Condensate (Igwan Etonex Co., Ltd.), which has a molecular structure of poly (styrene-co-styrenesulfonic acid) or poly (2-acrylamido-2-methyl-1propanesulfonic acid-co-acrylonitrile) May also be used.

In the present invention, the reason for using the conductive polymer doped with the polymer acid in which the sulfonic acid is substituted is due to three important functions described below. First, to increase the solubility of the conductive polymers in water to enable water dispersion to form a stable solution without phase separation from the silica sol solution with alcohol as a solvent, second, intermolecular hydrogen bonding with the silica sol is possible (For example, hydrogen bonding with (silica sol) -Si-OH ... HO ₃ S- (polymer)) to form a uniform organic-inorganic hybrid, and third, conductive polymer after coating film formation This is because they play an important role in increasing long-term safety by increasing their thermal and atmospheric stability.

The solution of the silica sol used for the purpose of increasing the hardness of the coating film in the present invention is prepared by mixing an inorganic acid as an alkoxysilane, water, a solvent and a catalyst, such as tetraethoxysilane (TEOS), as already known.

The solvent may be used to select at least one or more of alcohol, N-methylpyrrolidone (NMP) and dimethylformamide (DMF).

Hereinafter, the present invention will be described in more detail.

Manufacture of conductive polymer solution (solution A)

To prepare a polyaniline (PAN) aqueous solution, the polymer acid dopant was dissolved in water, and then the aniline chloride solution and the oxidizing agent aqueous solution were stirred for 24 hours while incubating for 1 hour at the same time. To synthesize polyaniline at a low temperature of about 15 ℃.

Here, the effect of adding more slowly by diluting the concentration of the oxidant solution is obtained, and the reason for synthesizing polyaniline at low temperature is to obtain the effect of increasing the molecular weight of polyaniline.

The molar ratio of the dopant to the aniline chloride is preferably 0.5 to 2.0, the concentration of the aniline chloride is about 0.2 mol / l, the oxidizing agent is preferably added in 1.1 equivalents to the aniline chloride.

Ammonium sulfate or sodium sulfate is mainly used as an oxidizing agent, and when polystyrene sulfonate is used as a polymer acid dopant, hydrochloric acid is added to the polymer compound to be converted into an acid.

The solution thus prepared is purified by dialysis for 3 days and then stored in solution. The concentration of the polyaniline solid content including the polymeric acid dopant is further adjusted to 1.5% by weight by adding water.

Instead of the above polystyrene sulfonate, beta-naphthalene sulfonate formalin condensate (Igwan Econex Co., Ltd.) or melamine sulfonate formalin condensate (Igun Eco Co., Ltd.) may be used as the polymer acid dopant. When the polymer acid dopant may be used, the concentration of the solid content of polyaniline may be slightly different, so that water is added to the polystyrene sulfonate to adjust the concentration of the solid content to 1.5% by weight.

When the conductive polymer solution is a polypyrrole (PPy) aqueous solution, it is prepared by the following method.

That is, when 2.0 equivalents of pyrrole and 1 to 2 equivalents of oxidizing agent are added dropwise in the presence of 2.0 equivalents of a polymeric acid dopant, an aqueous solution in which polypyrrole is well dispersed can be obtained. The aqueous polypyrrole solution was dialyzed and purified for 3 days, stored in solution, and water was further added to adjust the concentration of the solid to 1.5% by weight.

Preparation of aqueous polydioxyethylenethiophene (PEDT) solution is the same as the synthesis method of polydioxyethylenethiophene described in the previously known US Patent No. 5,391,472. That is, 14 g of polystyrene sulfonate (molecular weight Mn 40,000) was dissolved in 1 L of aqueous solution, 12.9 g of potassium peroxide sulfate (K ₂ S ₂ O ₈ ), 1 g of Fe ₂ (SO ₄ ) ₃ , and 5.68 g of 3 , 4-ethylenedioxythiophene is added, the reaction mixture is mixed with stirring at 20 ° C. for 24 hours, and finally the dialysis purification is completed, and the concentration of the solid is adjusted to 1.5% by weight by adding water.

As the polymer acid dopant, beta-naphthalene sulfonate formalin condensate (Eg. Co., Ltd.) or melamine sulfonate formalin condensate (Eg. Co., Ltd.) can be used instead of the polystyrene sulfonate. have. In the case of using such a polymeric acid dopant, since the concentration of the solid content may be slightly different, water is further added as in the case of the polystyrene sulfonic acid to adjust the concentration of the solid content to 1.5% by weight.

Table 1 lists the types of the water-soluble conductive polymer solution (solution 1) of the present invention prepared above.

Kinds Conductive polymer Dopant menstruum Solids concentration CP1 PAN PSSNa water 1.5 parts by weight CP2 PAN NapSNa water 1.5 parts by weight CP3 PAN MelSNa water 1.5 parts by weight CP4 PPy PSSNa water 1.5 parts by weight CP5 PPy NapSNa water 1.5 parts by weight CP6 PPy MelSNa water 1.5 parts by weight CP7 PEDT PSSNa water 1.5 parts by weight CP8 PEDT NapSNa water 1.5 parts by weight CP9 PEDT MelSNa water 1.5 parts by weight

PAN: polyaniline, PPy: polypyrrole, PEDT: polydioxyethylenethiophene, PSSNa: polystyrene sulfonate, NapSNa: beta-naphthalene sulfonate formalin condensate, MelSNa: melamine sulfonate formalin condensate.

Silica Sol Solution (Solution B) Preparation

As is well known, the silica sol solution uses at least one of alcohol, N-methylpyrrolidone (NMP) and dimethylformamide (DMF) as a solvent of tetraethoxysilane (TEOS), and as a reaction initiator, The catalyst is composed of an inorganic acid such as hydrochloric acid, nitric acid or sulfuric acid, and these materials are mixed and left to stand for about 1 hour at pH = 1 to 2 and room temperature to generate silica sol through a catalytic reaction as in Scheme 1 below.

Scheme 1 (gelation)

(Hydrolysis)

nSi (OCH ₃ ) ₄ + nH ₂ O → nSi (OH) ₄ + 4nH ₂ O

(polymerization)

Dimer: Si (OH) ₄ + Si (OH) ₄ → (HO) ₃ Si-O- (OH) ₃

Terpolymer: (HO) ₃ Si-O-Si (OH) ₃ + Si (OH) ₄ → (HO) ₃ Si-O-Si-O-Si (OH) ₃

Oligomer

:

polymer

:

In the present invention, in order to facilitate mixing with the conductive polymer aqueous solution (solution A), the concentration of TEOS affecting the molecular weight and concentration of the silica sol is adjusted to 5% by weight.

Molecular structure of the sol is important in order to have a good mixing and film hardness desired in the present invention, the concentration molecular structure of silica sol is affected by the water / TEOS molar ratio of the compact structure when the water / TEOS = 4 or more in acidic solution A sol is formed to have a compact spherical shape, and in the case of 4 or less, a sol having a coarse structure (the polymer chain of silicasol is close to a linear structure) is formed to have a linear shape.

In particular, the most suitable water / TEOS molar ratio is on the order of 1-30. If the ratio is 1 or less, the mixing with the conductive polymer aqueous solution is poor, and the film uniformity is poor. On the contrary, if the ratio is 30 or more, the structure of the sol is too compact (dense structure) and mixed with the conductive polymer to be sufficient for the purpose of the present invention. It will not show the hardness.

In addition, when the concentration of TEOS increases, the molecular weight of the silica sol is also relatively large.

In the present invention, at least one of alcohol, N-methylpyrrolidone (NMP) and dimethylformamide (DMF) is 3 to 10 parts by weight of the solvent in order to improve the solubility of the conductive polymer aqueous solution as the solvent used in the silica sol solution. It is good to mix and use to the extent.

Examples of alcohols that are solvents used in the silica sol solution in the present invention are most preferably 1 to 4 methanol, ethanol, propanol, isopropanol or butanol. If a higher alcohol having 5 or more carbon atoms is used, it is difficult to evaporate the solvent after coating, and thus high temperature baking is required.

Hard Coating Preparation by Mixing Solution A and Solution B

Referring to the manufacturing process of the polymer hard coating composition having transparency and conductivity according to the present invention.

The polymer hard coating composition of the present invention is prepared by mixing a conductive polymer aqueous solution (solution A) and a silica sol solution (solution B). In order to achieve a good film conductivity (10 ⁶ Ω / □ or less), film transparency (80% or more), film hardness (pencil hardness of 4H or more) that satisfies the purpose of the present invention, it should have an appropriate composition ratio.

That is, the composition is suitably 20 to 50% by weight of the conductive polymer aqueous solution (0.3 to 0.75% by weight) and 50 to 80% by weight of the silica sol solution (0.3 to 0.75% by weight), and the reason is as follows.

When the conductive polymer aqueous solution is 20% by weight or less and the silica sol solution is 80% by weight or more, when the coating on the surface of the transparent substrate, a relatively high amount of conductive polymer having high viscosity and dark coloring (for example, black and cobalt color) is relatively small. Therefore, the coating property is good, the transparency is good, and as the concentration of silica sol increasing the film hardness increases, the film hardness becomes good, but the conductivity is 10 ⁶ Ω / square or more, It is not suitable.

On the contrary, when the amount of the conductive polymer solution is 50% by weight or more and the silica sol solution is 50% by weight or less, the conductivity according to the increase of the conductive high molecular weight is very good, but the coating property is poor due to the increase in viscosity when coating the transparent substrate surface. And poor transparency due to increased colorability, poor transparency due to increased colorability, and poor film hardness due to a decrease in the amount of silica sol.

When the present invention is composed of 20 to 50% by weight of the conductive polymer aqueous solution and 50 to 80% by weight of the silica sol solution as described above, there is no problem in reaching the target level desired by the present invention. Most preferably, it is 30 to 40 weight% of conductive polymer aqueous solution, and 60 to 70 weight% of silica sol solutions. This composition is not only excellent in coating properties, but also maintains the physical property conductivity of the film 10 ¹ to 10 ⁵ Ω / □, the transparency to 95 to 85%, the film hardness of 5 to 8H to maintain the optimum balance of the three physical properties.

Method for producing a hard coating film with a transparency and conductivity of the hard coating composition is as follows.

That is, the solution of the hard coating composition of the present invention is poured onto a transparent substrate surface such as glass, CPP film, polyethylene terephthalate (PET) film, polycarbonate (PC) and polymethyl methacrylate (PMMA) panel and coated with bar. After uniform coating by spin coating or drying for about 1 to 2 hours in a drying oven at 100 to 200 ° C., a hard coating film according to the present invention is made.

The transparent conductive polymer hard coating film thus prepared can be most effectively used for TV CRT glass surface, computer monitor screen surface and safety glasses surface for electromagnetic shielding and antistatic, and also for CPP and PET film, PC and PMMA panel surface for the same purpose. Can be used.

Hereinafter, the present invention will be described in more detail with reference to the following examples.

Examples 1-9 and Comparative Examples 1-4

In Examples 1 to 9 of Table 2 below, examples of the polymer hard coating composition of the present invention are shown, and Comparative Examples 1 to 3 and 4 are obtained when only one of the conductive polymer hard coating composition and the silica sol solution is coated alone. The result is.

Here, the conductive polymer aqueous solution is CP1 to CP9 exemplified in Table 1 and the solid content is 1.5% by weight. The composition of the silica sol was 5 wt% of tetraethoxysilane (TEOS), ethanol and isopropanol (IPA) mixed solution (1: 1), and was used in the composition of 12 moles of water / TEOS. Silica sol solution. The preparation of the transparent conductive polymer coating film prepared for the physical property evaluation is as follows.

The mixed solution prepared in the present examples was stirred for about 2 hours, washed thoroughly with acid, bar-coated to a thickness of 25 mu on the dried glass surface, and dried in a 150 ° C. oven for about 1 hour. The thickness of the dried coating film was all 2 micrometers or less.

In the physical property evaluation, the conductivity was evaluated as surface resistance with an ohm meter, the transparency was evaluated as UV-Visible 480 nm transmittance, and the film hardness was evaluated as pencil hardness. The results are shown in Table 2 below.

Conductive Polymer Aqueous Solution / Silica Sol Solution (wt%) Membrane water castle Conductivity (Ω / □) Transparency (T%) Hardness (H) Membrane uniformity Example 1 CP1 / silica sol solution (30/70) 12 × 10 ³ 87 6 Good Example 2 CP2 / silica sol solution (30/70) 16 × 10 ³ 87 6 Good Example 3 CP3 / silica sol solution (30/70) 20 × 10 ³ 88 6 Good Example 4 CP4 / silica sol solution (30/70) 30 × 10 ³ 88 6 Good Example 5 CP5 / silica sol solution (30/70) 40 × 10 ³ 89 6 Good Example 6 CP6 / silica sol solution (30/70) 36 × 10 ³ 90 6 Good Example 7 CP7 / silica sol solution (30/70) 10 × 10 ³ 93 6 Good Example 8 CP8 / silica sol solution (30/70) 9 × 10 ³ 96 6 Good Example 9 CP9 / silica sol solution (30/70) 8 × 10 ³ 96 6 Good Comparative Example 1 CP1 / silica sol solution (100/0) 5 × 10 ² 70 8 or less Bad Comparative Example 2 CP2 / silica sol solution (100/0) 8 × 10 ² 72 8 or less Bad Comparative Example 3 CP3 / silica sol solution (100/0) 6 × 10 ² 76 8 or less Bad Comparative Example 4 CP4 / silica sol solution (0/100) Insulator 10 ¹² or more 100 9 or more Good

In Examples 1 to 9, when compared to the result of coating the conductive polymer aqueous solution alone (Comparative Examples 1 to 3), the film hardness is very excellent, and only the silica sol solution is coated alone (Comparative Example 4). Compared with the results, the conductivity was excellent.

Examples 10 to 13 and Comparative Examples 5 to 10

Examples 10 to 13 of the following Table 3 show another example of the present invention, and show the results in comparison with Comparative Examples 5 to 10, which deviate from the composition of the present invention. The conductive polymer aqueous solution and the silica sol solution used here are the same as those shown in Examples 1 to 9 above.

In the same manner as in Examples 1 to 9, a coating method, a baking method, and a property measurement method were performed.

Conductive Polymer Aqueous Solution / Silica Sol Solution (wt%) Membrane water castle Conductivity (Ω / □) Transparency (T%) Hardness (H) Membrane uniformity Example 10 CP7 / silica sol solution (25/85) 5 × 10 ⁵ 97 8 Good Example 11 CP7 / silica sol solution (35/65) 6 × 10 ³ 93 6 Good Example 12 CP7 / silica sol solution (40/60) 4 × 10 ³ 90 6 Good Example 13 CP7 / silica sol solution (45/55) 2 × 10 ³ 88 6 Good Comparative Example 5 CP7 / silica sol solution (15/85) 8 × 10 ⁶ 97 9 Good Comparative Example 6 CP7 / silica sol solution (10/90) 20 × 10 ⁶ 97 9 Good Comparative Example 7 CP7 / silica sol solution (5/95) 80 × 10 ⁶ 99 9 or more Good Comparative Example 8 CP7 / silica sol solution (55/45) 8 × 10 ² 74 One Bad Comparative Example 9 CP7 / silica sol solution (60/40) 4 × 10 ² 72 One Bad Comparative Example 10 CP7 / silica sol solution (70/30) 2 × 10 ² 70 HB Very good

The results of Examples 10 to 13 well indicate that the polymer hard coating composition having the desired transparency and conductivity in the present invention, Comparative Examples 5 to 7 do not show the desired result in the present invention because of the low conductivity, Comparative Example 8 9 to 9 are not suitable in terms of transparency, film hardness, and dispersibility.

The examples exemplified in Table 3 are only a part of the present invention, and exemplify only typical compositions.

Examples 14-18 and Comparative Examples 11, 12

Examples 14 to 18 and Comparative Examples 11 and 12 are for evaluating the film properties according to the molecular structure of the silica sol solution in the mixture of the conductive polymer aqueous solution and the silica sol solution according to the water / TEOS molar ratio. As shown in Table 4 below. The mixing ratio of the conductive polymer (CP7) aqueous solution / silicasol solution exemplified here is 35/75 wt% in common, the TEOS concentration of the silica sol solution is 5 wt%, and the solvent is mixed with methanol and isopropanol (1: 1 by weight). Solvent was used. The water / TEOS molar ratio is shown in Table 4 below.

The production method of the coating film, the baking method, the measurement method of the physical properties, etc. were the same as in Examples 1 to 9.

Water / TEOS Membrane water castle Conductivity (Ω / □) Transparency (T%) Hardness (H) Membrane uniformity Example 14 One 9 × 10 ³ 93 6 Good Example 15 4 8 × 10 ³ 93 7 Good Example 16 10 7 × 10 ³ 94 8 Good Example 17 20 6 × 10 ³ 94 6 Good Example 18 30 6 × 10 ⁶ 95 5 Good Comparative Example 11 0.5 10 × 10 ³ 96 3 Bad Comparative Example 12 35 8 × 10 ³ 96 2 Bad

Examples 14 to 18 of Table 4 show a result meeting the physical property targets of the present invention when the water / TEOS ratio is within 1 to 30, whereas when the conditions deviate from the conditions as in Comparative Examples 11 and 12. It was found that the film hardness and the film uniformity were poor.

The examples illustrated in Table 4 above are merely a part of the present invention, and illustrate only representative compositions. Other compositions not illustrated also show results consistent with the present invention.

The present invention provides a transparent and conductive polymer hard coating composition in which a water-soluble conductive polymer solution using a polymer acid as a dopant is mixed with a silica sol solution prepared from alkoxysilane (tetraethoxysilane), water, a solvent, and an inorganic acid. In the mixed solution of the present invention, a conductive transparent coating film having excellent glass and synthetic resin surface hardness can be prepared, and the mixed solution of the present invention has excellent solubility in water and alcohol, and thus has excellent processability (coating property). By adjusting the type and amount of solvent, there is an advantage that the thickness of the coating film can be sufficiently adjusted.

Claims (6)

A polymer hard coating composition having transparency and conductivity, comprising 20 to 50 wt% of a conductive polymer aqueous solution and 50 to 80 wt% of a silica sol solution. The polymer hard coating composition of claim 1, wherein the conductive polymer aqueous solution is selected from polyaniline, polypyrrole, and polydioxyethylenethiophene aqueous solution. The method of claim 1, wherein the conductive polymer aqueous solution and the silica sol solution is a solid hard polymer composition having transparency and conductivity, characterized in that the concentration of the solid content is 0.3 to 0.75% by weight. The method of claim 1, wherein the silica sol solution is selected from one or more of tetraethoxysilane as a monomer, water as a reaction initiator, alcohol, N-methylpyrrolidone and dimethylformamide as a solvent, and an inorganic acid as a catalyst. A polymer hard coating composition having transparency and conductivity, which is prepared by mixing. 5. The polymer hard coating composition of claim 4, wherein the molar ratio of water / tetraethoxysilane is 1 to 30. Transparency, characterized by having a conductivity of 10 ¹ to 10 ⁵ Ω / □, transparency of 95 to 85%, film hardness of 5 to 8H by coating the polymer hard coating composition according to claim 1 on a transparent substrate Polymer hard coating film having conductivity.