JPH07310034A - Transparent antistatic plate - Google Patents

Abstract

PURPOSE:To produce a transparent antistatic plate having excellent scratch resistance, etc., by forming a transparent conductive layer composed of electrically conductive powder and a binder resin composed mainly of a (meth)acrylate compound on a plastic substrate. CONSTITUTION:This antistatic plate is produced by coating the surface of a plastic substrate with a transparent conductive layer composed of (A) 100 pts.wt. of electrically conductive powder having particle diameter of 0.01-2mum and produced by coating barium sulfate particle with tin oxide containing antimony oxide and (B) 20-70 pts.wt. of a binder resin composed mainly of a (meth) acrylate compound having >=2 (meth)acryloyl groups in one molecule [e.g. ethylene glycol di(meth)acrylate or diethylene glycol di(meth)acrylate].

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transparent antistatic plate having excellent scratch resistance.

[0002]

2. Description of the Related Art Conventionally, electrostatic charge is extremely disliked for semiconductor wafer storage containers, electronic / electrical members, floor materials / wall materials in semiconductor manufacturing plants, etc.
Those having antistatic properties are used. In general,
In order to impart antistatic performance to a molded body made of synthetic resin, for example, coating with paint containing carbon powder or metal powder, or kneading carbon powder, carbon fiber or metal fiber into synthetic resin at the time of molding A method of mixing and molding is performed. However, these methods have a problem in that a transparent material cannot be obtained due to the coloring of the paint or the molded body itself and the content cannot be seen through when used in the window portion.

Therefore, JP-A-58-91777 discloses a transparent coating material containing a conductive fine powder containing tin oxide as a main component in a binder. This paint can form a coating film having high transparency and antistatic performance, but since the binder is a thermoplastic resin, it is generally impossible to obtain a coating film excellent in scratch resistance and solvent resistance. There was a point.

Further, Japanese Patent Laid-Open No. 60-60166 discloses a transparent coating material containing a conductive fine powder containing tin oxide as a main component in a binder. This paint contains a component that cures with ultraviolet rays or visible light, and the coating film has good transparency and antistatic performance, and forms a coating film excellent in scratch resistance and solvent resistance.

With this coating material, a substrate having a relatively high surface hardness such as an acrylic resin can be provided with sufficient scratch resistance and transparency can be maintained even if the thickness of the coating film is reduced. However, for substrates with relatively low surface hardness such as vinyl chloride resin and polycarbonate, it is necessary to thicken the coating in order to impart sufficient scratch resistance, which reduces the transparency of the coating. There was a problem to do.

[0006]

The present invention has been made in view of the above problems, and its object is not only a plastic base material having a relatively high surface hardness such as an acrylic resin but also a vinyl chloride resin. Another object of the present invention is to provide a transparent conductive plate having a transparent conductive layer excellent in scratch resistance even on a plastic substrate having a relatively low surface hardness such as polycarbonate.

[0007]

The transparent conductive plate of the present invention comprises a plastic base material and a transparent conductive layer provided on the plastic base material. The transparent conductive layer comprises conductive powder (a) and (meth) acrylate. It is formed of a conductive composition containing a binder resin (b) containing a compound as a main component.

As the conductive powder (a), barium sulfate particles coated with tin oxide containing antimony oxide are used. The barium sulfate particles are colorless,
Since the refractive index is 1.6 and almost the same as that of the binder resin (b), it does not scatter light rays and imparts high transparency, and the coated tin oxide containing antimony oxide exhibits conductivity. .

When the particle size of the conductive powder (a) becomes small, when a thick transparent conductive layer capable of exhibiting sufficient conductivity is formed, the volume ratio of the barium sulfate particles decreases and the transparency deteriorates. , Becomes larger, the smoothness of the transparent conductive layer decreases,
Since minute air holes are generated in the gaps of the conductive powder (a), the transparency of the transparent conductive layer is deteriorated, so the thickness is limited to 0.01 to 2 μm.

The binder resin (b) contains a (meth) acrylate compound having at least two (meth) acryloyl groups in the molecule as a main component. Examples of the (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 (meth). ) 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 [4- (acryloxydiethoxy) ) Phenyl] propane, 2,2-bis [4- (methacryloxydiethoxy) phenyl] propane, 3-phenoxy-2-propanoyl acrylate, 1,6-bis (3-acryloxy-2-hydroxypropyl) -hexyl Bifunctional (meth) acrylates such as ether; pentaerythritol tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, glycerol tri (meth) acrylate, tris- (2-hydroxyethyl) -isocyanate Trifunctional (meth) acrylates such as acid ester (meth) acrylate; tetrafunctional or higher (meta) acrylates such as pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate ) Acrylate and the like.

Furthermore, when an acrylic urethane oligomer having a (meth) acryloyl group at the molecular end and a urethane bond in the molecule is added to the above (meth) acrylate compound, the scratch resistance of the resulting coating film is further improved. To do. Two or more kinds of such acrylic urethane oligomers may be used in combination.

The ratio of the (meth) acrylate compound to the acrylic urethane oligomer is 1 in weight ratio because the scratch resistance is lowered even if either one is added excessively.
The range of 0:90 to 90:10 is preferable.

Preparation of such an acrylic urethane oligomer is carried out, for example, by reacting a compound having two or more isocyanate groups in one molecule with a (meth) acrylate 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-2,5-diisocyanate and toluene-2. , 6-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.

The (meth) acrylate having active hydrogen is, for example, 2-hydroxyethyl (meth) acrylate.
Acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, glycerin di (meth) acrylate, 1,6-bis (3-acryloxy-2-hydroxypropyl) -hexyl ether, pentaerythritol tri ( Examples thereof include (meth) acrylate, tris- (2-hydroxyethyl) isocyanuric acid ester (meth) acrylate, and (meth) acrylic acid.

In the conductive composition, when the amount of the binder resin (b) is small, the crosslinking density is low and the scratch resistance and chemical resistance are poor, and when it is large, the amount of the conductive powder is relatively large. Since the amount becomes small and sufficient conductivity cannot be obtained, 20 to 20 parts by weight of the conductive powder (a) is used.
Limited to 70 parts by weight.

In the conductive composition, a dispersant may be added to the binder resin (b) in order to enhance the dispersibility of the conductive powder (a). Examples of the dispersant include anionic surfactants such as sodium dialkylsulfosuccinate and sodium alkylnaphthalenesulfonate; cationic surfactants such as stearyltrimethylammonium chloride; ester-based surfactants such as sorbitan monostearate; vinyl chloride. Alternatively, a (meth) acrylic acid ester monomer 7 represented by the following general formula (1)
5 to 98 mol%, vinyl alcohol, a hydroxyl group-containing monomer represented by the following general formula (2) or a hydroxyl group-containing monomer represented by the following general formula (3) 2 to 25 mol%,
A copolymer composed of 0 to 18 mol% of another copolymerizable monomer; and a polyvinyl acetal resin.

[0018]

[Chemical 1]

In the above general formula (1), R ¹ represents hydrogen or a methyl group, and R ² represents an alkyl group or an aryl group having 10 or less carbon atoms.

[0020]

[Chemical 2]

In the general formula (2), R ³ is hydrogen or a methyl group, and m is an integer of 1-10.

[0022]

[Chemical 3]

In the above general formula (3), R ⁴ is hydrogen or a methyl group, n is an integer of 1-9, and k is an integer of 2-10.

Examples of the (meth) acrylic acid ester represented by the above general formula (1) include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, and (meth) acrylic acid. n-butyl, (meth)
Examples thereof include n-hexyl acrylate, n-oxyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, and phenyl (meth) acrylate. It may also be a halogen-substituted (meth) acrylic acid ester such as 2-chloroethyl (meth) acrylate.

Examples of the hydroxyl group-containing monomer represented by the above general formula (2) include hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate,
Examples thereof include hydroxybutyl (meth) acrylate and hydroxyoctyl (meth) acrylate.

Examples of the hydroxyl group-containing monomer represented by the above general formula (3) include polyethylene glycol mono (meth) acrylates such as triethylene glycol mono (meth) acrylate and tetraethylene glycol mono (meth) acrylate. And polypropylene glycol mono (meth) acrylates such as tripropylene glycol mono (meth) acrylate and tetrapropylene glycol mono (meth) acrylate.

Other copolymerizable monomers include styrene, α-methylstyrene, vinyl acetate and the like.

In the above copolymer, when the amount of the vinyl alcohol or the hydroxyl group-containing monomer becomes small, the conductive powder (b) is obtained.
Is not able to be uniformly dispersed, the transparency of the coating film is deteriorated, and the chemical resistance of the resulting coating film is deteriorated when the amount is increased. Therefore, it is limited to 2 to 25 mol%, preferably 5 to 20 mol%. is there.

In addition, the amount of the other copolymerizable monomer in the above copolymer is limited to 0 to 18 mol% because if the amount of the other copolymerizable monomer increases, the coatability is deteriorated.

The polyvinyl acetal resin is obtained by acetalizing polyvinyl alcohol by condensation reaction with aldehyde. This acetalization is carried out by a precipitation method using an aqueous medium in the presence of an acid catalyst,
A known method such as a dissolution method using a solvent such as alcohol is adopted. It is also possible to use polyvinyl acetate as a raw material and perform saponification and acetalization in parallel to obtain a polyvinyl acetal resin.

The polyvinyl alcohol preferably has an average degree of polymerization of 200 or more. Average degree of polymerization is 2
When it is less than 00, it is difficult to synthesize polyvinyl alcohol and only a solution having a low solution viscosity can be obtained, which is not preferable.

Examples of the aldehyde include formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde, amylaldehyde, hexylaldehyde, heptylaldehyde, octylaldehyde,
2-ethylhexyl aldehyde, decyl aldehyde, cyclohexyl aldehyde and the like can be mentioned. The above aldehydes may be used alone or in combination of two or more.

The above polyvinyl acetal resin is
Other than the acetalization site, an acetyl group may be contained in a proportion of 10% by weight or less. When the residual hydroxyl group in the acetal resin is small, the effect of dispersing the conductive powder (a) is insufficient, and when the residual hydroxyl group is large, the chemical resistance is adversely affected. Therefore, 2-60 mol% is preferable, and 5 is more preferable. ~
It is 40 mol%.

The amount of the dispersant in the conductive composition is
When the amount decreases, the dispersibility of the conductive powder (a) deteriorates and the transparency decreases, and when the amount increases, the hardness, scratch resistance and chemical resistance of the coating film decrease, so 100 parts by weight of the conductive powder (a) is used. On the other hand, 5 to 100 parts by weight is preferable.

If necessary, various additives such as an ultraviolet absorber, an antioxidant, a thermal polymerization inhibitor, a leveling agent, a surface modifier and a defoaming agent may be added to the conductive composition. Good. In addition, an organic solvent may be added to the conductive composition in order to enhance coatability or adhesion when forming the transparent conductive layer on the surface of the plastic plate.

Examples of the organic solvent include methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, ethylene glycol monomethyl ether (methyl cellosolve), ethylene glycol monoethyl ether (ethyl cellosolve), butyl acetate, isopropyl acetone and anisole. You may use it in mixture of 2 or more types.

To prepare the conductive composition used for forming the transparent conductive layer, the conductive powder (a) is well dispersed in the binder resin (b), and is used for dispersion or mixing of the paint. Equipment, eg sand mill, ball mill,
Attritors, high-speed rotary agitators, three rolls, etc. are used.

The conductive composition prepared by the above method is added to
After coating on a plastic substrate by a general coating method such as a spray method, a bar coating method, a doctor blade method, a roll coating method, a dipping method, ultraviolet rays, visible rays, by curing by radiation or heating, A transparent conductive layer is formed. As the plastic substrate,
Examples thereof include transparent plastic plates made of vinyl chloride resin, acrylic resin, polycarbonate, polystyrene and the like.

The light source for curing the ultraviolet rays is not particularly limited, and a conventionally known light source can be used. For example, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a metal halide lamp and the like are preferably used.

Examples of the radiation include electron beams, X-rays, γ-rays and the like.

The obtained transparent conductive layer is preferably surface-finished by buffing. With this surface finish,
As the transparency of the transparent conductive layer is improved, the conductive powder that easily falls off the surface is removed, so that no dust is generated from the transparent conductive layer during use, and it is suitable for use in semiconductor manufacturing where dust is extremely disliked. .

[0042]

EXAMPLES Examples of the present invention will be described below. (Example 1) 33 parts by weight of dipentaerythritol hexaacrylate, 1 part by weight of diethylthioxanthone and p
1 part by weight of ethyl dimethylaminobenzoate was dissolved in 260 parts by weight of methyl cellosolve and charged in an attritor. While stirring this, a conductive powder having an average particle size of 0.45 μm (“Pastran type-IV” manufactured by Mitsui Kinzoku Co., Ltd.) coated with antimony oxide-containing tin oxide 10
A conductive composition was prepared by adding 0 parts by weight and 5 parts by weight of oleic acid and performing dispersion for 6 hours.

The conductive composition was applied to one side of a transparent acrylic resin plate having a thickness of 3 mm by a bar coater, and then dried with hot air at 50 ° C. for 10 minutes to form a coating film.
This coating film was irradiated with a high pressure mercury lamp at an irradiation dose of 1800 mJ /
The transparent conductive layer was formed by irradiating with ultraviolet rays so that the transparent conductive layer had a thickness of cm ² . The obtained transparent conductive layer has a diameter of 30 cm,
The surface was buffed with a wool polisher at 3000 rpm. Further, a transparent conductive layer was formed on the other surface of the acrylic resin plate in the same manner to obtain a transparent antistatic plate.

(Example 2) A transparent conductive layer was formed in the same manner as in Example 1 except that a transparent vinyl chloride resin plate having a thickness of 3 mm was used in place of the transparent acrylic resin plate to prevent transparent electrification. A plate was obtained.

(Example 3) A transparent conductive layer was formed in the same manner as in Example 1 except that a transparent polycarbonate plate having a thickness of 3 mm was used in place of the transparent acrylic resin plate to form a transparent antistatic plate. Obtained.

Example 4 30 parts by weight of dipentaerythritol hexaacrylate, diethyl thioxanthone 1
Parts by weight and 1 part by weight of ethyl p-dimethylaminobenzoate were dissolved in 260 parts by weight of methyl cellosolve and charged in an attritor. While stirring this, the average particle size coated with antimony oxide-containing tin oxide was 0.45μ.
m of conductive powder (Mitsui Kinzoku Co., Ltd. "Past run type-
IV ") and 100 parts by weight of residual hydroxyl group and 35 parts by weight of residual hydroxyl group and 9 parts by weight of butyral resin having a degree of polymerization of 1700 were added and dispersed for 6 hours to prepare a conductive composition. Using the above conductive composition, a transparent conductive layer was formed on both sides of a transparent acrylic resin plate having a thickness of 3 mm by the same method as in Example 1 to obtain a transparent antistatic plate.

Example 5 A transparent conductive layer was formed in the same manner as in Example 4 except that a transparent vinyl chloride resin plate was used instead of the transparent acrylic resin plate,
A transparent antistatic plate having a thickness of 3 mm was obtained.

(Example 6) A transparent conductive layer was formed in the same manner as in Example 4 except that a transparent polycarbonate plate having a thickness of 3 mm was used in place of the transparent acrylic resin plate to form a transparent antistatic plate. Obtained.

(Example 7) 30 parts by weight of dipentaerythritol triacrylate, 1 part by weight of diethylthioxanthone and 1 part by weight of ethyl p-dimethylaminobenzoate were dissolved in 300 parts by weight of cyclohexanone and charged into an attritor. While stirring this, the average particle size coated with antimony oxide-containing tin oxide was 0.45μ.
m of conductive powder (Mitsui Kinzoku Co., Ltd. "Past run type-
IV ") and 100 parts by weight of residual hydroxyl group, 35 mol% of residual hydroxyl group, and 10 parts by weight of acetoacetal resin having a polymerization degree of 2400 were added and dispersed for 8 hours to prepare a conductive composition. Using the above conductive composition, a transparent conductive layer was formed on both sides of a transparent acrylic resin plate having a thickness of 3 mm by the same method as in Example 1 to obtain a transparent antistatic plate.

(Example 8) A transparent conductive layer was formed in the same manner as in Example 7 except that a transparent vinyl chloride resin plate having a thickness of 3 mm was used in place of the transparent acrylic resin plate to prevent transparent electrification. A plate was obtained.

(Example 9) A transparent conductive layer was formed in the same manner as in Example 7 except that a transparent polycarbonate plate having a thickness of 3 mm was used in place of the transparent acrylic resin plate to form a transparent antistatic plate. Obtained.

(Example 10) 28 parts by weight of dipentaerythritol hexaacrylate, 1 part by weight of diethylthioxanthone and 1 part by weight of ethyl p-dimethylaminobenzoate were dissolved in a mixed solvent of 150 parts by weight of methyl ethyl ketone and 150 parts by weight of ethyl cellosolve. I made it into an attritor. While stirring this, a conductive powder coated with antimony oxide-containing tin oxide and having an average particle size of 0.45 μm (“Pastran type-I” manufactured by Mitsui Kinzoku Co., Ltd.
V ") 100 parts by weight and 10 parts by weight of a copolymer of vinyl chloride (90 mol%) and hydroxyacrylate (10 mol%) (" Eslec E-HA "manufactured by Sekisui Chemical Co., Ltd.) are added and dispersed for 6 hours. A conductive composition was thus prepared. Using the above conductive composition, a transparent conductive layer was formed on both sides of a transparent acrylic resin plate having a thickness of 3 mm by the same method as in Example 1 to obtain a transparent antistatic plate.

(Example 11) A transparent conductive layer was formed in the same manner as in Example 10 except that a transparent vinyl chloride resin plate having a thickness of 3 mm was used in place of the transparent acrylic resin plate to prevent transparent electrification. A plate was obtained.

(Example 12) A transparent conductive layer was formed in the same manner as in Example 10 except that a transparent polycarbonate plate having a thickness of 3 mm was used in place of the transparent acrylic resin plate to form a transparent antistatic plate. Obtained.

Example 13 20 parts by weight of dipentaerythritol triacrylate, 10 parts by weight of pentaerythritol tetraacrylate, 1 part by weight of benzophenone and 1 part by weight of p-dimethylaminoacetophenone, 150 parts by weight of methyl ethyl ketone and 150 parts of cyclohexanone.
It was dissolved in a mixed solvent with parts by weight and charged into an attritor. While stirring this, a conductive powder (“Pastran type-IV” manufactured by Mitsui Kinzoku Co., Ltd.) 100 having an average particle size of 0.45 μm coated with antimony oxide-containing tin oxide.
A conductive composition was prepared by adding 10 parts by weight of a copolymer of 80 parts by weight of methyl methacrylate and 20% by weight of 2-hydroxyethyl acrylate and dispersing for 6 hours. Example 1 using the above conductive composition
A transparent conductive layer was formed on both sides of a transparent acrylic resin plate having a thickness of 3 mm by the same method as described above to obtain a transparent antistatic plate.

(Example 14) A transparent conductive layer was formed in the same manner as in Example 13 except that a transparent vinyl chloride resin plate having a thickness of 3 mm was used in place of the transparent acrylic resin plate to prevent transparent electrification. A plate was obtained.

(Example 15) A transparent conductive layer was formed in the same manner as in Example 13 except that a transparent polycarbonate plate having a thickness of 3 mm was used in place of the transparent acrylic resin plate to form a transparent antistatic plate. Obtained.

Comparative Example 1 Average particle diameter 2.3 μm coated with tin oxide containing antimony oxide as a conductive powder
A transparent conductive layer was formed in the same manner as in Example 1 except that the barium sulfate particles in Example 1 were used to obtain a transparent antistatic plate.

(Comparative Example 2) A transparent conductive layer was formed in the same manner as in Comparative Example 1 except that a transparent vinyl chloride resin plate having a thickness of 3 mm was used in place of the transparent acrylic resin plate to prevent transparent electrification. A plate was obtained.

Comparative Example 3 A transparent conductive layer was formed in the same manner as in Comparative Example 1 except that a transparent polycarbonate plate having a thickness of 3 mm was used in place of the transparent acrylic resin plate to form a transparent antistatic plate. Obtained.

(Comparative Example 4) The same procedure as in Example 1 was repeated except that an antimony oxide-containing tin oxide powder ("T-1" manufactured by Mitsubishi Materials) having a primary particle size of 0.02 µm was used as the conductive powder. A transparent conductive layer was formed to obtain a transparent antistatic plate.

Comparative Example 5 A transparent conductive layer was formed in the same manner as in Comparative Example 4 except that a transparent vinyl chloride resin plate having a thickness of 3 mm was used in place of the transparent acrylic resin plate to prevent transparent electrification. A plate was obtained.

(Comparative Example 6) A transparent conductive layer was formed in the same manner as in Comparative Example 4 except that a transparent polycarbonate plate having a thickness of 3 mm was used in place of the transparent acrylic resin plate to form a transparent antistatic plate. Obtained.

Comparative Example 7 A transparent conductive layer was formed in the same manner as in Example 1 except that 8 parts by weight of dipentaerythritol hexaacrylate was used to obtain a transparent antistatic plate.

Comparative Example 8 A transparent conductive layer was formed in the same manner as in Comparative Example 7 except that a transparent vinyl chloride resin plate having a thickness of 3 mm was used in place of the transparent acrylic resin plate to prevent transparent electrification. A plate was obtained.

(Comparative Example 9) A transparent conductive layer was formed in the same manner as in Comparative Example 7 except that a transparent polycarbonate plate having a thickness of 3 mm was used in place of the transparent acrylic resin plate to form a transparent antistatic plate. Obtained.

Comparative Example 10 A transparent conductive layer was formed in the same manner as in Example 1 except that 70 parts by weight of dipentaerythritol hexaacrylate was used to obtain a transparent antistatic plate.

(Comparative Example 11) A transparent conductive layer was formed in the same manner as in Comparative Example 10 except that a transparent vinyl chloride resin plate having a thickness of 3 mm was used in place of the transparent acrylic resin plate to prevent transparent electrification. A plate was obtained.

Comparative Example 9 A transparent conductive layer was formed in the same manner as in Comparative Example 10 except that a transparent polycarbonate plate having a thickness of 3 mm was used in place of the transparent acrylic resin plate to form a transparent antistatic plate. Obtained.

The transparent conductive plates obtained in the above Examples and Comparative Examples were subjected to the following measurements and performance evaluations, and the results are shown in Table 1. (1) Film thickness The conductive composition was applied on a plastic substrate by a bar coater, dried with hot air at 50 ° C. for 10 minutes to form a coating film, and then a part of the coating film was peeled off and irradiated with ultraviolet rays. The coating was cured. Next, a surface profiler ("De
ktak3030 "), the step difference between the cured coating film forming portion and the cured coating film non-forming portion was measured and used as the film thickness of the transparent conductive layer. (2) Surface resistivity The surface resistivity was measured according to ASTM D257. (3) Total light transmittance and haze Total light transmittance and haze were measured according to ASTM D1003. (4) Half-life of charged voltage It was measured with a static Honest meter. (5) Scratch resistance After performing a sliding test of 100 with steel wool (# 0000) having a load of 1 kg / cm ² , the cured coating film was evaluated according to the following evaluation criteria. 1: Many scratches were observed. 2: A considerable number of scratches were recognized. 3: 2-3 scratches were recognized. 4: A slight scratch was recognized. 5: No scratch was observed.

[0071]

[Table 1]

[0072]

[Table 2]

[0073]

[Table 3]

[0074]

[Table 4]

[0075]

[Table 5]

[0076]

The structure of the transparent antistatic plate of the present invention is as described above, and even if the film thickness of the transparent conductive layer is increased, a high light transmittance is exhibited and a plastic substrate having a relatively low surface hardness is used. High scratch resistance can be imparted also to the material.

Claims (1)

[Claims] 1. A plastic substrate on which (a) 100 parts by weight of a conductive powder having a particle size of 0.01 to 2 μm, which is obtained by coating barium sulfate particles with antimony oxide-containing tin oxide, and (b) at least 2 in the molecule. A transparent antistatic plate, wherein a transparent conductive layer comprising 20 to 70 parts by weight of a binder resin containing as a main component a (meth) acrylate compound having at least one (meth) acryloyl group is formed.