JPH0748462A - Production of antistatic transparent sheet - Google Patents

Abstract

PURPOSE:To provide a method for producing an antistatic transparent sheet excellent in electric conductivity, transparency, scuff resistance and hardness. CONSTITUTION:This method for producing an antistatic transparent sheet is composed of the first step for coating one surface of a transparent sheet with an inorganic electrically conductive coating, irradiating the coated sheet with active rays of light, curing the coating and providing a laminate and the second step for applying an organic electrically conductive coating onto the formed electrically conductive film in the first layer, then irradiating the applied coating with the active rays of light, curing the coating and the provided the antistatic transparent sheet. The inorganic electrically conductive coating is composed of an acrylate or a methacrylate compound, electrically conductive powder consisting essentially of a metallic oxide and a photopolymerization initiator and the organic electrically conductive coating is composed of the acrylate or methacrylate compound, a polymer of a conjugated compound and a photopolymerization initiator.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to conductivity, scuff resistance,
The present invention relates to a method for producing an antistatic transparent sheet having excellent hardness and transparency.

[0002]

2. Description of the Related Art Conductive synthetic resin moldings are used for their properties such as semiconductor wafer storage containers, electronic / electrical members, floor materials and wall materials in semiconductor manufacturing factories. Conventionally, in order to impart conductivity to a synthetic resin molded body, the synthetic resin molded body is coated with a coating material containing carbon powder or metal powder, or carbon powder, carbon fiber, metal fiber or the like is kneaded into the synthetic resin. It is being molded in.

However, in these conventional methods, the coating film obtained and the synthetic resin molded product itself are colored, so that they are opaque and the contents cannot be seen through. There was a problem that I could not.

Further, in recent years, in the semiconductor industry, there is a tendency to eliminate metal components from clean rooms, and conductive materials using organic compounds are desired.

Further, Japanese Patent Laid-Open No. 61-285216 discloses a method in which a heterocyclic monomer having nitrogen or sulfur is applied to the surface of a molded body and polymerized with an oxidizing agent to form an organic conductive polymer layer on the molded body. However, there is a problem that the polymer layer lacks strength and is easily scratched or peeled off.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method capable of easily producing an antistatic transparent sheet which has conductivity and is excellent in transparency, scratch resistance, hardness and chemical resistance. It is in.

[0007]

The inorganic conductive paint used in the first step of the present invention comprises a (meth) acrylate compound, a conductive powder containing a metal oxide as a main component, and a photopolymerization initiator.

The above-mentioned (meth) acrylate compound is a (meth) acrylate compound having two or more (meth) acryloyl groups in the molecule. Examples of such a (meth) acrylate compound include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, nonaethylene glycol di. (Meta)
Acrylate, polyethylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, tetrapropylene glycol di (meth) acrylate, nonapropylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, 2,2-bis Bifunctional (meth) acrylates such as [4-((meth) acryloxydiethoxy) phenyl] propane and 1,6-bis (3-acryloxy-2-hydroxypropyl) hexyl ether, or pentaerythritol tri (meth) acrylate. , Trimethylolpropane tri (meth) acrylate, glycerol tri (meth) acrylate, trifunctional (meth) acrylates such as tris ((meth) acryloxyethyl) isocyanurate, pentaerythri Rutetora (meth) acrylate, dipentaerythritol penta (meth) acrylate, tetrafunctional or more (meth) acrylates such as dipentaerythritol hexa (meth) acrylate.

Further, as a (meth) acrylate compound other than the above, an acrylic urethane oligomer having two or more (meth) acryloyl groups at the terminal of the molecule and having a urethane bond in the molecule can also be obtained as the first-layer conductive material. The coating film is excellent in abrasion resistance and suitable. Such an acrylic urethane oligomer is prepared, for example, by reacting a compound having two or more isocyanate groups in one molecule with a (meth) acrylate compound having active hydrogen.

Examples of the compound having two or more isocyanate groups in one molecule include m-phenylene diisocyanate, p-phenylene diisocyanate, toluene-2,4-diisocyanate, toluene-2,6-diisocyanate and toluene-2. , 5-diisocyanate, toluene-3,5-diisocyanate, m-xylylene diisocyanate, p-xylylene diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, isophorone diisocyanate, 4,4′-diphenylmethane diisocyanate, 4,4 ′ -Diisocyanate-3,3'-dimethylbiphenyl, 4,4'-diisocyanate-3,3'-
Dimethylbiphenylmethane and the like can be mentioned.

Examples of the active hydrogen-containing (meth) acrylate compound include 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, glycerin di (meth) acrylate and 1,6-bis (3-). Examples thereof include acryloxy-2-hydroxypropyl) -hexyl ether, pentaerythritol tri (meth) acrylate, (meth) acrylic acid and the like. The (meth) acrylate compounds may be used alone or in combination.

When a (meth) acrylate compound having one (meth) acryloyl group in the molecule is added,
The obtained first layer conductive coating film is suitable because it imparts flexibility and toughness.

The conductive powder is not particularly limited as long as it contains a metal oxide as a main component. Examples thereof include antimony-containing tin oxide, barium sulfate coated with antimony-containing tin oxide, tin oxide-containing indium oxide, tin oxide and the like. If the average particle size of the antimony-containing tin oxide is large, the conductive powder scatters visible light,
If the transparency of the obtained first-layer conductive coating film is lowered, and if it is small, the conductivity of the obtained first-layer conductive coating film is lowered, the tin oxide is apt to settle, and the paint is gelled. 0.01 μm to 0.4 μm is preferable because it tends to occur.

When the content of antimony is low, the conductivity of the first-layer conductive coating film obtained is low, and when it is high, the transparency of the first-layer conductive coating film obtained is low. 20
Weight percent is preferred. Such antimony-containing tin oxide is sold under the trade name T-1 by Mitsubishi Materials Corporation.

When the average particle size of barium sulfate coated with antimony-containing tin oxide is small, the transparency of the obtained first-layer conductive coating film is low, and when it is large, the first-layer conductive coating film is transparent. Since the surface smoothness is deteriorated, 0.
1 μm to 2 μm is preferable. Such barium sulfate coated with antimony-containing tin oxide is sold by Mitsui Metals under the trade name Pastran Type-IV.

If the particle size of the tin oxide-containing indium oxide is large, the conductive powder scatters visible light, and the transparency of the first-layer conductive coating film obtained is reduced. The conductivity of the conductive coating film is further reduced, the indium oxide is likely to settle, and the coating material is easily gelated. Therefore, 0.01 μm to 0.4 μm is preferable.

When the content of tin oxide in the tin oxide-containing indium oxide is small, the conductivity of the first-layer conductive coating film obtained is low, and when it is large, the transparency of the first-layer conductive coating film obtained is low. Therefore, 0.1 to 20% by weight is preferable.

If the particle size of tin oxide is large, the conductive powder scatters visible light, and the transparency of the obtained first layer conductive coating film is lowered. Conductivity of the conductive coating film decreases, and the tin oxide easily precipitates, and
0.01μm-0.4 because the paint is easy to gel
μm is preferred.

The conductive powder is added in an amount of 100 to 100 relative to 100 parts by weight of the (meth) acrylate compound.
Limited to 100 parts by weight. If it is more than 10000 parts by weight, the transparency of the first-layer conductive coating film obtained will decrease, and
If the amount is less than 0 parts by weight, the conductivity of the obtained first-layer conductive coating film decreases.

The photopolymerization initiator is not particularly limited as long as it has a property of initiating the photopolymerization of the (meth) acrylate compound by an actinic ray such as an ultraviolet ray. For example, sodium dimethyldithiocarbamate, diphenyl monosulfide, dibenzothiazoyl monosulfide and sulfides; thioxanthone, 2-ethylthioxanthone, 2-chlorothioxanthone, 2,4-
Thioxanthone derivatives such as diethylthioxanthone; azo compounds such as hydrazone and azobisisobutyronitrile; diazo compounds such as benzenediazonium salts; benzoin, benzoin methyl ether, benzoin ethyl ether, benzophenone, dimethylaminobenzophenone, Michler's ketone, benzylanthraquinone, t -Butylanthraquinone, 2-methylanthraquinone, 2-
Ethyl anthraquinone, 2-amino anthraquinone, 2
An aromatic carbonyl compound such as chloroanthraquinone;
Dialkylaminobenzoic acid esters such as methyl p-dimethylaminobenzoate, ethyl p-dimethylaminobenzoate, butyl p-dimethylaminobenzoate and isopropyl p-diethylaminobenzoate; benzoyl peroxide, di-t-butyl peroxide, Peroxides such as dicumyl peroxide and cumene hydroperoxide; acridine derivatives such as 9-phenylacridine, 9-p-methoxyphenylacridine, 9-acetylaminoacridine and benzacridine; 9,10-dimethylbenzphenazine, 9 -Methylbenzphenazine, 10
-Phenazine derivatives such as methoxybenzphenazine;
^6,4,, 4 ^,, - trimethoxy-2,3-quinoxaline derivatives such as diphenyl quinoxaline; 2,4,5 triphenyl imidazolyl dimers, 2-nitrofluorene,
2,4,6-triphenylpyrylium tetrafluoride boron salt, 2,4,6-tris (trichloromethyl) -1,
3,5-triazine, 3,3, -carbonylbiscoumarin ^, thiomichler ketone and the like can be mentioned.

When the amount of the photopolymerization initiator added is small, the photopolymerization of the (meth) acrylate compound does not proceed completely,
Since the hardness and scuff resistance of the obtained first-layer conductive coating film decrease, and when the amount is large, the weather resistance of the obtained first-layer conductive coating film decreases, so that it is based on 100 parts by weight of the (meth) acrylate compound. Therefore, 0.1 to 20 parts by weight is preferable.

The inorganic conductive coating material used in the present invention comprises a conductive powder containing the above metal oxide as a main component, a (meth) acrylate compound and a photopolymerization initiator, but does not impair the physical properties, if necessary. Within the range, organic solvent, dispersant,
A sensitizer, an ultraviolet absorber, a thermal polymerization inhibitor, an antioxidant, a surface modifier, a defoaming agent, etc. may be added.

The above organic solvent is added to adjust the paint viscosity of the inorganic conductive paint. For example, methanol, methyl ethyl ketone, cyclohyxanone, ethylene glycol monomethyl ether (methyl cellosolve), ethylene glycol monoethyl ether, (ethyl cellosolve)
Etc.

If the amount of the organic solvent added is small, the transparency of the conductive coating film for the first layer obtained will be low, and if it is large, the viscosity of the coating will be low and the coatability will be low. Since there is a problem that only the first-layer conductive coating film thinner than the film thickness can be formed, 100 parts by weight of the conductive powder is added to 100 parts by weight.
˜2000 parts by weight is preferred.

The above-mentioned dispersant is added to improve the dispersibility of the electroconductive powder. Examples of the dispersant include oleic acid, acetic acid, (meth) acrylic acid, p-styrenesulfonic acid and the like. Organic acids, polyvinyl butyral and polyvinyl acetals such as polyacetoacetal (acetalized by condensation reaction of polyvinyl alcohol and acetaldehyde), copolymers of methyl methacrylate and 2-hydroxyethyl methacrylate, vinyl chloride and vinyl acetate Polymer compounds such as copolymers with and the like can be mentioned.

The sensitizer is added to improve the sensitivity of the photopolymerization initiator. Examples of the sensitizer include dimethylaminoacetophenone, Michler's ketone, ethyl 2-dimethylaminobenzoate and p-. Ethyl dimethylaminobenzoate and the like can be mentioned.

Any method may be adopted as the method for producing the inorganic conductive coating material. For example, a conductive powder containing the above-mentioned metal oxide as a main component, a (meth) acrylate compound, a photopolymerization initiator, etc. may be used in a sand mill. , A ball mill, an attritor, a homogenizer, a dissolver, etc., and mixed and dispersed.

The transparent sheet used in the present invention also includes plates and films. For the transparent sheet, for example, polyethylene, polypropylene, polyvinyl chloride,
Examples thereof include synthetic resin sheets, synthetic resin plates and synthetic resin films made of polycarbonate, acrylic resin, ABS resin and the like. Further, it may be an inorganic substance such as glass.

The first step of the present invention is to coat one surface of the transparent sheet with the above-mentioned inorganic conductive coating material, and then irradiate it with actinic rays,
This is a step of curing to obtain a laminate having the first-layer conductive coating film formed thereon.

The method for applying the above-mentioned inorganic conductive coating material to one surface of the transparent sheet is not particularly limited, and a general application method is used. For example, a spin coating method, a spraying method, a roll coater method, a bar coating method, a doctor blade method, a dipping method and the like can be mentioned. After applying the inorganic conductive coating on one surface of the transparent sheet, when adding an organic solvent, it is dried with hot air, infrared rays, etc., and then irradiated with actinic rays using a high-pressure mercury lamp or a metal halide lamp to be cured, A first layer conductive coating film is formed.

When the thickness of the first-layer conductive coating film is thin, the conductivity and scuff resistance of the first-layer conductive coating film obtained are lowered,
Further, if the thickness is thick, the transparency of the first-layer conductive coating film obtained is lowered, so 0.5 to 3 μm is preferable. If the irradiation amount of actinic rays is small, the curing of the first-layer conductive coating becomes insufficient,
Since the abrasion resistance, the hardness, and the adhesion to the transparent sheet of the obtained first-layer conductive coating film are deteriorated, the cumulative exposure amount is 50.
It is preferable to irradiate with actinic rays so that the irradiation amount becomes 0 mJ / cm ² or more.

The organic conductive paint used in the second step of the present invention comprises a (meth) acrylate compound, a polymer of a conjugated compound and a photopolymerization initiator. As the (meth) acrylate compound and the photopolymerization initiator, the same ones as those used in the inorganic conductive coating are used.

The polymer of the conjugated compound is not particularly limited as long as it has conductivity. For example, a hetero five-membered cyclic compound such as pyrrole, thiophene, furan and selenophene, a hetero five-membered cyclic compound derivative such as N-alkylthiophene, 3-alkylpyrrole, 3-alkylthiophene and 3,4-dialkylthiophene, benzene , Biphenyl and ta-phenyl and their derivatives, polynuclear aromatic compounds such as naphthalene and anthracene, and polymers of aniline, pyridazine and azulene and their derivatives are used.

The method for preparing the polymer is not particularly limited, and a general method is used. Examples thereof include an electrolytic polymerization method and a chemical polymerization method using persulfate as an oxidizing agent.

The amount of the polymer containing the conjugated compound added is
5 to 100 parts by weight of the (meth) acrylate compound
Limited to ~ 100 parts by weight. When the amount is less than 5 parts by weight, the electroconductivity of the electroconductive coating film obtained is insufficient, and 10
When it is more than 0 parts by weight, the coating strength of the obtained conductive coating film is lowered.

The organic conductive coating material comprises the above-mentioned (meth) acrylate compound, a polymer of a conjugated compound and a photopolymerization initiator, but if necessary, within the range not impairing the physical properties,
Similar to inorganic conductive paint, organic solvent, dispersant, sensitizer,
An ultraviolet absorber, a thermal polymerization inhibitor, an antioxidant, a surface modifier, a defoaming agent, etc. may be added.

The organic conductive paint is prepared in the same manner as the inorganic conductive paint. In the second step of the present invention, the organic conductive coating material is applied on the first-layer conductive coating film, followed by irradiation with actinic rays to cure the second-layer conductive coating film on the first-layer conductive coating film. Is a step of obtaining an antistatic transparent sheet obtained by laminating.

As a method of applying the organic conductive coating material, irradiating with actinic rays and curing the same, the same method as that of the inorganic conductive coating material is used.

[0039]

EXAMPLES Examples of the present invention will be described below. (Example 1) 35 parts by weight of dipentaerythritol hexaacrylate, 0.1 part by weight of hydroquinone, 350 parts by weight of ethyl cellosolve, 1 part by weight of 2,4-diethylthioxanthone, and 1 part by weight of dimethylaminoacetophenone were supplied to an attritor. , Mixed and dispersed. Further, while stirring the dispersion liquid, 100 parts by weight of tin oxide (trade name T-1 manufactured by Mitsubishi Materials Corp.) containing antimony and having an average particle diameter of 0.02 μm and the ratio of residual hydroxyl groups to all hydroxyl groups are 34%. Degree of acetalization with butyraldehyde 65%, ratio of acetyl groups to all hydroxyl groups 1%,
16 parts by weight of polyvinyl butyral having an average degree of polymerization of 1900 was added to the dispersion over 20 minutes. Furthermore, dispersion was carried out for 10 hours to obtain an inorganic conductive coating material.

The inorganic conductive coating material obtained was applied to one surface of the acrylic resin plate so that the thickness of the first-layer conductive coating film was 1.5 μm.
It is applied by a spin coating method so that
After hot-air drying at ℃ for 10 minutes, high pressure mercury lamp (30
0W), the cumulative exposure of actinic rays is 1800 m
The laminate was irradiated with an actinic ray so as to be J / cm ² and cured to obtain a laminate in which the first-layer conductive coating film was formed on one surface of the acrylic resin plate.

Next, in a separable flask reaction vessel equipped with a condenser, a stirrer and a dropping funnel, 35 wt% hydrochloric acid 5
00 ml and 36.5 ml of aniline were supplied, and 500 ml of 35 wt% hydrochloric acid containing 91 parts by weight of ammonium peroxodisulfate was further added to the mixture while controlling the temperature rise in a water bath.
Add over 0 minutes and stir for 3 hours. The obtained precipitate was collected by filtration to obtain green polyaniline hydrochloride. The obtained polyaniline hydrochloride was washed with a 10% by weight aqueous sodium hydroxide solution, and further washed with water and methanol to obtain polyaniline powder.

5 parts by weight of the obtained polyaniline powder, 50 parts by weight of pentaerythritol triacrylate, 1,6
-Bis (3-acryloxy-2-hydroxypropyl)
Hexyl ether 50 parts by weight, benzophenone 3 parts by weight, Michler's ketone 1 part by weight, hydroquinone 1 part by weight,
150 parts by weight of ethyl cellosolve was supplied to an attritor and stirred for 12 hours to obtain an organic conductive paint.

Using the obtained organic conductive coating material, coating on the first layer conductive coating film in the same manner as the inorganic conductive coating material,
An actinic ray was irradiated and cured to obtain an antistatic transparent sheet in which the second-layer conductive coating film was laminated on the first-layer conductive coating film.

The conductivity, transparency, hardness and scratch resistance of the obtained antistatic transparent sheet were measured by the following methods, and the results are shown in Table 1. (Conductivity) Surface resistivity was measured according to ASTM-D257. (Transparency) Haze value was measured according to ASTM-D1003.

(Hardness) Pencil hardness was measured according to JIS K5400. (Scratch resistance) The surface specific resistance, pencil hardness and haze value after the test according to JIS K7204 were measured. (Taber wear wheel CS10 × 500g load × 100 times)

Example 2 Except that the first conductive coating film formed on the laminate obtained in Example 1 was buffed.
An antistatic transparent sheet was obtained in the same manner as in Example 1. The conductivity, transparency, hardness, and scratch resistance of the obtained antistatic transparent sheet were measured by the same methods as in Example 1, and the results are shown in Table 1.

(Comparative Example 1) The inorganic conductive coating material obtained in Example 1 was coated with an acrylic resin plate in the same manner as in Example 1 so that the thickness of the first-layer conductive coating film was 3 μm. One surface of the acrylic resin plate was coated, dried, and irradiated with an actinic ray to obtain a laminate in which the first-layer conductive coating film was formed on one surface of the acrylic resin plate. The conductivity, transparency, hardness, and scratch resistance of the obtained laminate were measured by the same methods as in Example 1, and the results are shown in Table 1.

Comparative Example 2 The first-layer conductive coating film formed on the laminate obtained in Comparative Example 1 was buffed to obtain a buffed laminate. The conductivity, transparency, hardness, and scuff resistance of the obtained buffed laminate were measured by the same methods as in Example 1, and the results are shown in Table 1.

Example 3 100 parts by weight of pentaethithritol triacrylate, 0.2 parts by weight of hydroquinone,
4 parts by weight of 2,4-diethylthioxanthone and 4 parts by weight of ethyl p-dimethylaminobenzoate were added to cyclohexanone 1
It was added to 400 parts by weight and supplied to an attritor. While stirring this, barium sulfate (trade name Pastelan Ty manufactured by Mitsui Kinzoku Co., Ltd., further coated with tin oxide containing antimony and having an average particle diameter of 0.2 μm)
pe-IV) 400 parts by weight and 30 parts by weight of polyacetoacetal having a ratio of residual hydroxyl groups to the total hydroxyl groups of 35% and an average polymerization degree of 2400 were added and dispersed for 10 hours to obtain an inorganic conductive coating material.

A laminate was obtained in the same manner as in Example 1 except that the obtained inorganic conductive coating material was applied so that the thickness of the first-layer conductive coating film was 3 μm. Using the organic conductive coating material obtained in Example 1, the film thickness of the second layer conductive coating film is 3
An antistatic transparent sheet was obtained in the same manner as in Example 1 except that the coating was performed so that the thickness became μm.

The conductivity, transparency, hardness, and scratch resistance of the resulting antistatic transparent sheet were measured by the same methods as in Example 1, and the results are shown in Table 2.

(Example 4) An antistatic transparent sheet was obtained in the same manner as in Example 3 except that the first layer conductive coating film formed on the laminate obtained in Example 3 was buffed. .

The conductivity, transparency, hardness and scratch resistance of the resulting antistatic transparent sheet were measured by the same methods as in Example 1 and the results are shown in Table 2.

(Comparative Example 3) The inorganic conductive coating material obtained in Example 3 was coated with an acrylic resin plate in the same manner as in Example 3 so that the thickness of the first-layer conductive coating film was 6 μm. One surface of the acrylic resin plate was coated, dried, and irradiated with an actinic ray to obtain a laminate in which the first-layer conductive coating film was formed on one surface of the acrylic resin plate.

The conductivity, transparency, hardness, and
The scratch resistance was measured by the same method as in Example 1, and the results are shown in Table 2.

Comparative Example 4 The first-layer conductive coating film formed on the laminate obtained in Comparative Example 3 was buffed to obtain a buffed laminate. The conductivity, transparency, hardness and scuff resistance of the obtained buffed laminate were measured by the same methods as in Example 1, and the results are shown in Table 2.

[0057]

[Table 1]

[0058]

[Table 2]

[0059]

The structure of the method for producing an antistatic transparent sheet of the present invention is as described above, and the obtained antistatic transparent sheet has conductivity, and is excellent in transparency and scuff resistance. . In addition, since no inorganic conductive material is used for the conductive coating film on the surface, there is no emission of impurities and it can be suitably used as an antistatic material for semiconductor-related products.

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Claims (1)

[Claims] [Claims] 1. A first step of obtaining a laminate having a first-layer conductive coating film formed thereon by applying an inorganic conductive coating material on one surface of a transparent sheet, followed by irradiating with actinic rays to cure the organic conductive coating material and organic conductivity. After coating the coating on the first-layer conductive coating, irradiating with actinic rays to cure it, and obtain an antistatic transparent sheet in which the second-layer conductive coating is laminated on the first-layer conductive coating. A method for producing an antistatic transparent sheet, which comprises a second step, wherein the inorganic conductive coating material is mainly composed of 100 parts by weight of a (meth) acrylate compound having two or more (meth) acryloyl groups in the molecule and a metal oxide. 100 to 10,000 parts by weight of a conductive powder as a component and a photopolymerization initiator, and the organic conductive coating material has 100 or more parts by weight of a (meth) acrylate compound having two or more (meth) acryloyl groups in the molecule, a conjugated system. Compound polymer 5-100 weight Method for producing a transparent antistatic sheet characterized by comprising a part and a photopolymerization initiator.