JPS6157660A - Antistatic transparent paint - Google Patents

Abstract

PURPOSE:To provide the titled paint containing an organic binder composed mainly of a specific hydroxyl-containing copolymer and a urethane elastomer, and electrically conductive powder composed mainly of tin oxide, having excellent chemical resistance, abrasion resistance, etc., and useful as an electronic part, etc. CONSTITUTION:The objective paint can be prepared by compounding (A) an organic binder containing (i) a hydroxyl-containing copolymer composed of 2-30 (mol)% hydroxyl-containing vinyl monomer, 70-98% vinyl chloride and 0-28% polymerizable monomer and (ii) a urethane elastomer at a weight ratio of preferably 1:4-4:1 with (B) electrically conductive powder composed mainly of tin oxide having particle diameter of <=0.2mum. EFFECT:A coating film having excellent durability, antistatic property, etc. can be formed.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention provides an antistatic coating material, in particular, which has antistatic function and transparency, and is excellent in abrasion resistance and chemical resistance.

The present invention relates to a paint that can form a durable paint film.

(Prior art) Semi-wrap wafer storage containers, clean benches, clean rooms, electronic/electrical components, flooring and wall materials of semiconductor manufacturing factories, etc., need to have an antistatic effect depending on their use. . for that.

Conventionally, these members have been coated with paint containing carbon powder or metal powder, or molded by kneading carbon powder, carbon fiber, metal fiber, etc. into resin. However, in these conventional methods, the coating film and the molded article themselves are colored and are therefore opaque, making it impossible to see through the contents. Therefore, it is not possible to use a window as a portion that requires antistatic protection. Another disadvantage is that carbon powder may fall off due to friction on the painted surface.

JP-A-57-85866 discloses a transparent paint having an antistatic function. This paint is made by containing in a paint binder a conductive fine powder with a particle size of 0.2 μm or less, the main component of which is tin oxide containing antimony.

In this paint, it is difficult to disperse the conductive fine powder to a high degree, and it is difficult for the coating film obtained by coating a resin member to stably exhibit transparency and antistatic function.

(Problems to be Solved by the Invention) An object of the present invention is to provide a coating material with excellent transparency and antistatic effect. Another object of the present invention is to provide a paint that has excellent abrasion resistance and chemical resistance, and is capable of forming a durable coating film that maintains antistatic effect and transparency for a long period of time.

(Means for Solving the Problems) The present invention provides that when a hydroxyl group-containing copolymer is contained in the binder component of a paint, the conductive powder contained in the paint is effectively dispersed; This work was completed based on the inventors' new knowledge that when a urethane elastomer is included in the binder component, the abrasion resistance of the resulting coating film is significantly superior.

Therefore, the antistatic transparent paint of the present invention contains an organic binder and a conductive powder, and the main components are a copolymer containing the organic binder and the conductive powder, and a urethane elastomer. The conductive powder is mainly composed of vinyl monomer and vinyl chloride, and the conductive powder is mainly composed of tin oxide and has a particle size of less than 0.2 μm, thereby achieving the above object. Ru.

The hydroxyl group-containing vinyl monomer that is a constituent component of the hydroxyl group-containing copolymer of the present invention includes hydroxyethyl (meth)acrylate (represents both hydroxyethyl acrylate and hydroxyethyl methacrylate. The same applies hereinafter).

), hydroxypropyl (meth)acrylate Hydroxyalkyl (meth)acrylates such as hydroxybutyl (meth)acrylate and hydroxyoctyl (meth)acrylate; polyethylene glycol mono (
Meth)acrylate: Examples include polypropylene glycol mono(meth)acrylate in which the number of repeating ether bond moieties is about 2 to 6. Such a hydroxyl group-containing vinyl monomer and conductive powder are used as constituent components of a copolymer containing 2
It is contained in a proportion of 30 mol% to 30 mol%, preferably 5 to 20 mol%. If the amount is too small, the conductive powder cannot be uniformly dispersed in the paint, and the resulting paint film will have poor transparency and smoothness. If it is included in excess, the resulting coating film will have poor chemical resistance.

Vinyl chloride is one of the constituent components of the hydroxyl group-containing copolymer.
It accounts for 98 mol%, preferably 80 to 95 mol%. By containing vinyl chloride as a constituent component, 2112 with excellent chemical resistance can be obtained.

In addition, as a constituent of hydroxyl group-containing copolymers.

A polymerizable jiL polymer having no hydroxyl group may be contained. Such polymerizable 1Lji contains styrene, vinegar fi! Examples include hinyl, (meth)acrylic acid ester, and olefin. These are contained in a proportion of 0 to 28 mol%.

The above-mentioned Alff1 body is synthesized into a hydroxyl group-containing copolymer by a conventional polymerization method, such as a solution polymerization method, an emulsion polymerization method, a suspension polymerization method, or a bulk polymerization method. This hydroxyl group-containing copolymer is
Instead of using a hydroxyl group-containing vinyl monomer, it can also be synthesized by copolymerizing with a monomer other than the hydroxyl group-containing vinyl monomer using vinyl acetate, and saponifying the resulting copolymer.

Urethane elastomers include polycondensates of isocyanates and linear saturated polyesters, polycondensates of isocyanates and linear saturated polyethers, and polycondensates of isocyanates and caprolactam.

Isocyanates include 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 1,3-21-
Silene diisocyanate, 1,4-xylene diisocyanate, 1,5-naphthalene diisocyanate 1-. m
- Phenyl diisocyanate.

p-phenylene diisocyanate, 3.3゛-dimethyl-4.4°-diphenylmethane diisocyanate, 4.4°-diphenylmethane diisocyanate, 3
-3'-dimethyl-4,4'-diphenylmethane diisocyanate 4,4'-diphenylmethane diisocyanate, 3,3'-dimethylbiphenylene diisocyanate, 4,4'-biphenylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate.

Examples include dicyclohexylmethane diisocyanate.

Linear saturated polyesters are obtained by polycondensation of polyhydric alcohols and saturated polybasic acids. One example of polyhydric alcohol is ethylene glycol.

These include diethylene glycol, glycerin, 1,4-butanediol, 1,6-hexanediol, sorbitol, neopentyl glycol, and 1,4-cyclohexane dimetatool. Examples of saturated polybasic acids include phthalic acid, isofucuric acid, terephthalic acid, maleic acid, succinic acid, adipic acid, and sebacic acid. Examples of linear saturated polyethers include polyethylene glycol, polypropylene glycol, polytetraethylene glycol, and the like.

Since the urethane elastomer is contained as an organic binder component, a coating film with excellent wear resistance can be obtained. The weight ratio of the hydroxyl group-containing copolymer to the urethane elastomer is 4:1 to 1:4. Contains ff of urethane elastomer
If fi is too low, the resulting coating film will have poor abrasion resistance. If it is in excess, the conductive powder will not be sufficiently dispersed, making it impossible to obtain a coating film with excellent transparency.

When a trifunctional or higher functional isocyanate compound is blended into a paint, the binder component is crosslinked to form a three-dimensional network structure after the paint film is formed. Therefore.

Mechanical properties such as abrasion resistance of the coating film are improved. Examples of trifunctional or higher functional isocyanates include the diisocyanates mentioned above. The isocyanate is contained in a proportion of 1 to 20% by weight based on the ffa binder.

The conductive powder contained in the paint is mainly composed of tin oxide.
', and its particle size is 0.2 μm end, preferably 0.2 μm.
It is 1 μm or less. For example, to further improve conductivity.

This conductive powder may contain a small amount of antimony, and in order to ensure excellent conductivity and transparency of the coating film, this conductive powder is added in an amount of 100 to 3
It is contained in a proportion of 50 to 1 parts by weight, preferably 120 to 300 parts by weight. i1! If the amount of static powder is too small, even if the degree of dispersion is sufficient, the coating film obtained will not exhibit sufficient conductivity, and therefore the antistatic effect, which is one of the objects of the present invention, will not be exhibited.

stomach. If it exceeds 350 parts by weight, it will become overcrowded, resulting in poor dispersion of the fine powder, and as a result, the transparency of the resulting coating film will be impaired.

The coating material of the present invention is prepared by first dissolving the organic binder in an organic solvent, and then mixing with a conductive powder containing tin oxide as a main component. The organic solvent may be used as long as it can dissolve the organic binder.

Conventional solvents may be used. For organic solvents.

For example, methyl ethyl ketone, cyclohexanone.

Examples include toluene, ethyl acetate, ethylene glycol monomethyl ether, and ethylene glycol monoethyl ether. These may be mixed and used as appropriate. Equipment commonly used for compounding paints to ensure that fine powder is sufficiently dispersed in the paint.

For example, a sand mill, a ball mill, a high-speed rotation stirring device, a three-roll mill, etc. can be used. In order to further improve the dispersion of this fine powder, silane coupling agents, titanate coupling agents, and surfactants are used.

Dispersion aids such as oleic acid and lecithin may also be used in combination.

In order to increase the durability of the coating film, an ultraviolet absorber or a stabilizer may be blended, and for coloring, various paints and the like may be contained within a range that does not impair the transparency of the coating film.

(Function) The antistatic transparent paint of the present invention prepared in this manner can be applied by spray method, roll coater method, flow coater method, etc.
It is applied to the object to be coated using a general coating method such as a barcode method, a doctor blade method, or a dipping method.

The surface resistivity of the coating film obtained in this way is 101
Because it is 1Ω/sq or less and has good conductivity.

Excellent antistatic effect can be obtained.

(Example) The present invention will be described below with reference to Examples.

FA'M of I material: hydroxyl group-containing copolymer containing 10 mol% of 2-hydroxypropyl acrylate and 90 mol% of vinyl chloride (S-LEC EHA; Block Chemical a)
50g of Niraporan 2302 (manufactured by Nippon Polyurethane Co., Ltd.) as a polyurethane elastomer
(in terms of solid content) was added to a mixed solution of 600 g of methyl ethyl ketone and 600 g of methyl isobutyl ketone. The obtained organic binder solution and a powder mainly composed of tin oxide with an average particle size of 0.1 μm or less (T-1; manufactured by Mitsubishi Metals)
200g was placed in a ball mill. After dispersing for 48 hours, 5 g (in terms of solid content) of Coronate (manufactured by Nippon Polyurethane Co., Ltd.) as an isocyanate compound was added to prepare a desired coating material.

(B) Preparation of coating film and performance evaluation: The coating obtained in section (A) was applied onto a polyester film to a thickness of 1 μm using a roll coater, and the solvent was dried. Regarding the electrical properties of the obtained coating film, ASTM D-257
The surface specific resistivity was measured based on the test method of .

Regarding transparency, total light transmittance and haze value were measured based on the test method of STM D-1003. Furthermore, regarding abrasion properties, a haze value was measured after 100 rotations with a load of 20 g using a C5-10 wear ring with a taper tester. The rate of increase in haze value after the Taber test was calculated and used as a measure of abrasion resistance. The respective values are shown in the table below.

Preparation of the main (A) paint: S-LEC A (manufactured by Building Block Chemical Co., Ltd., IylJ) containing about 8 mol% of vinyl alcohol, about 90 mol% of vinyl chloride, and about 2 mol% of vinyl acetate as a hydroxyl group-containing copolymer. Example 1 (A) except that
Same as section.

(B) Preparation of coating film and performance evaluation Two examples Using the paint obtained in section (A), performance evaluation was performed in the same manner as in section (B) of Example 1. The results are shown in the table below.

xJid 1 run (A) Preparation of paint: 70 g of Eslec A as a hydroxyl group-containing copolymer, 30 g of Niraporan 3022 (manufactured by Nippon Boriurekun Co., Ltd.) as a urethane elastomer in terms of solid content, and 15 g of Coronate L as an isocyanate compound in terms of solid content. It is the same as Example 1 except that it was used.

(B) Preparation of coating film and performance evaluation: Using the coating obtained in section (A) of this example, it was coated on a vinyl chloride resin plate to a thickness of 2 μm.
Example 1 except that spray painting was performed so that
Same as item (B).

Comparison Example 5 (A) Preparation of f4 material: Same as Example 1 (A) except that Eslec EHAIQOg was used as the organic binder and no polyurethane elastomer was added.

(B) Preparation of coating film and performance evaluation Two comparative examples Using the paint obtained in section (A), the performance was evaluated in the same manner as in section (B) of Example 1. The results are shown in the table below.

This 1U raw material 1 (A) Paint made by M: S-LEC E as an organic binder
It is the same as Example 3 (A) except that 100 g of HA was used and no polyurethane elastomer was added.

(B) Preparation of coating film and performance evaluation Two Examples Using the coating obtained in section (A), a film of 2 μm thickness was coated on a vinyl chloride resin plate.
Example 1 except that spray painting was performed so that
Same as item (B).

(Effects of the Invention) The antistatic transparent coating of the present invention can form a coating film that is highly transparent and exhibits an excellent antistatic effect.

The coating also has outstanding abrasion resistance and chemical resistance. Furthermore, since a highly durable coating film is formed that retains its antistatic effect and transparency over a long period of time, its range of application is significantly wider than that of conventional antistatic paints.

that's all

Claims (1)

[Claims] 1. Contains an organic binder and a conductive powder, the organic binder is mainly composed of a hydroxyl group-containing copolymer and a urethane elastomer, and the copolymer is composed of a hydroxyl group-containing vinyl monomer and a chlorinated vinyl monomer. The conductive powder is mainly composed of vinyl and the conductive powder is mainly composed of tin oxide and has a particle size of 0.2μ.
Transparent anti-static paint with a value below m. 2. The hydroxyl group-containing copolymer contains 2 to 30 mol% of a hydroxyl group-containing vinyl monomer, 70 to 98 mol% of vinyl chloride, and 0 to 28 mol% of other polymerizable monomers. The paint according to claim 1. 3. The paint according to claim 1, wherein the weight ratio of the hydroxyl group-containing copolymer to the urethane elastomer is 1:4 to 4:1. 4. The paint according to claim 1, wherein the conductive powder is contained in a proportion of 100 to 350 parts by weight based on 100 parts by weight of the organic binder. 5. The coating material according to claim 1, wherein the coating material further contains a difunctional or more functional isocyanate compound.