JPS6354473A - Electrically conductive paint composition - Google Patents

Abstract

PURPOSE:To provide the title compsn. which can be easily cured by ultraviolet light, visible light, etc., and gives a coating film having excellent electrical conductivity, transparency, solvent resistance and hardness, by blending an epoxy resin with specified electrically conductive powder and a photo-curing catalyst. CONSTITUTION:100pts.wt. epoxy resin (A) having at least two, pref. at least three epoxy groups (e.g., a phenolic novolak type epoxy resin) is blended with 50-400pts.wt. electrically conductive powder (B) having an average particle size of not larger than 0.2mum, composed of tin oxide contg. 0.1-10wt% Sb, 0.1-10pts.wt. photo-curing catalyst (C) which is decomposed by ultraviolet light or visible light to release an acid component and cationically polymerizes an epoxy group [e.g., benzene-cyclopentadienyl-iron(II)-hexafluorophosphate] and optionally, an org. solvent (D) (e.g., methyl ethyl ketone).

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a conductive coating composition that can be easily cured by ultraviolet rays, visible light, etc., and can form a coating film with excellent conductivity and transparency.

[Conventional technology]

Semiconductor wafer storage containers, electronic/mechanical components, flooring and wall materials of semiconductor manufacturing factories, etc., need to have an antistatic effect depending on their use. To this end, conventionally, these members have been coated with paint containing carbon powder or metal powder, or carbon powder, carbon fiber, gold'r4&! I-fibers and the like are kneaded into resin and molded. However, with these conventional methods, the paint film and molded product itself are colored and are therefore opaque, making it impossible to see through the contents and making it impossible to use windows in areas that require antistatic protection. was there.

JP-A-57-85866 discloses a paint containing a paint binder containing conductive fine powder containing tin oxide as a main component. This paint can form a transparent coating film with antistatic function, but because the paint binder is a thermoplastic resin, the resulting coating film generally cannot exhibit high hardness, solvent resistance, etc. was there.

[Problem that the invention seeks to solve]

In view of the above drawbacks, the object of the present invention is to provide a coating composition that can be easily cured by ultraviolet rays, visible light, etc., has excellent solvent resistance and hardness, and can form a coating film that is also excellent in conductivity and transparency. It is about providing.

[Means for solving problems]

The epoxy resin used in the present invention only needs to have 2a or more epoxy groups, and any conventionally known resin can be used, but in order to improve the hardness and mechanical strength of the coating film, 3 or more epoxy groups It is preferable that the epoxy resin has an epoxy group of It is preferable to use it.

(In the formula, R1, 1ljj, RJ are hydrogen or methyl groups,
n is an integer of 1 to 5) The conductive powder used in the present invention is mainly composed of tin oxide, and tin oxide containing 7 nitimony (Ll to 20% by weight) is preferably used. In addition, the average particle diameter is limited to 2 μm or less because as it becomes large, it scatters visible light and the transparency of the resulting coating film decreases.

If the amount of conductive powder added is small, the conductivity of the coating film will be reduced, and if it is too large, the transparency and mechanical strength of the coating film will be reduced. is preferable.

The photocurable catalyst used in the present invention is a photocurable catalyst for epoxy resin that decomposes with ultraviolet rays or visible light, liberates acid components, and cationically polymerizes epoxy groups.
For example, an azonium salt with the general formula (where Y is an alkyl group, M
Xn is PF;, AaF;, sbp;, 5bcl;, Br
Examples include diaryliodonium salts represented by or, ruphonium salts of the general formula, benzene-cyclopentadienyl-iron-hexafluorophosphate, etc., and diaryliodonium salts and triaryl salts that have good storage stability when made into coating compositions. Sulfonium salts and benzene
Cyclopentadienyl-iron (Ill-hexafluorophosphate) is preferably used.

The amount of addition of the photocurable catalyst may be appropriately determined depending on the use and curing conditions, but it is generally added in an amount of α1 to 10 parts by weight per 100 parts by weight of the epoxy resin.

The conductive coating composition of the present invention contains the above-mentioned epoxy resin, conductive powder, and photocurable catalyst, and when used as a coating, it is preferably dispersed and dissolved in an organic solvent.

Examples of the organic solvent include hydrocarbon solvents such as toluene, cyclohexane, and xylene, ketone solvents such as methyl ethyl ketone, methyl propyl ketone, methyl isobutyl ketone, methyl-n-butyl ketone, diisobutyl ketone, and cyclohexane, ethyl acetate, and acetic acid. n-
Examples include acetate ester solvents such as propyl, isopropyl acetate, and n-butyl acetate, cellosolve solvents such as methyl cellosolve, ethyl cellosolve, and butyl cellosolve, and carpitol solvents such as methyl calpitol, ethyl calpitol, and butyl calpitol. It is preferable that the conductive powder has good dispersibility, that the drying rate of the coating film is excessive, and that the adhesion between the coating surface and the coating film is excellent. Mixed solvents are preferably used.

Any method may be used to produce the conductive coating composition of the present invention, such as a method in which a conductive powder is added to an epoxy resin, uniformly dispersed, and then a photocurable catalyst is added, uniformly dispersed, and dissolved. However, a preferred method is to add an epoxy resin and a conductive powder to an organic solvent, uniformly disperse and dissolve it, and then add a photocurable catalyst to uniformly disperse and dissolve it.

For the above-mentioned dispersion and dissolution, equipment commonly used for dispersing and blending paints, such as a sand mill, a ball mill, a high-speed rotating stirring device, and a three-roll mill, can be used.

The conductive coating composition prepared as in ξ is applied to the object to be coated by a general coating method such as a spray method, a bar code method, a doctor blade method, or a dipping method.

The applied coating composition is cured by irradiation with ultraviolet rays or visible light, and a transparent conductive coating film is obtained.

〔Effect of the invention〕

Since the structure of the conductive coating composition of the present invention is as described above, it can be easily cured by ultraviolet rays, visible light, etc., and a coating film with excellent solvent resistance and hardness can be obtained. Since the main component is tin oxide and the average particle size is 0.2 μm or less, the obtained coating film has excellent transparency and conductivity. [Example] Next, the present invention will be explained in detail. Note that “department” means “department”.
"Parts by weight."

Example 1 80 parts of phenol novolac type epoxy tMH"Jc manufactured by Tobu Kasei Co., Ltd., trade name YDPN 63 g), conductive powder (conductive powder with a diameter of α1 μ or less obtained by doping antimony in oxidized tin with 10% doping, Mitsubishi Metals) Co., Ltd., trade name T-1) 160 parts, lecithin 2 parts, methyl ethyl ketone soom and ethyl cellosolve soo parts f-k
After dispersing and dissolving for 24 hours, 2 parts of benzene-cyclopentadienyl-iron-hexafluorophosphate were added and mixed to obtain a conductive coating composition.

Apply it to a thickness of 2 pm (dry) on the
After drying the solvent for 5 minutes at 50°C, a high pressure mercury lamp (
The coating film was cured by irradiating ultraviolet light for 5 minutes from a distance of 251 cm using an output of 5.6 KW and an effective lamp length of 70 countries.

The surface resistivity, total light transmittance, haze value, and solvent resistance of the resulting coating film were measured, and the results are shown in Table 1.

The surface resistivity was measured according to ASTM D-257, the total light transmittance and haze value were measured according to ASTM D-1003, and the solvent resistance was measured using a cloth impregnated with the specified organic solvent shown in Table 1. The surface was rubbed 100 times and the peeling state of the coating film was visually determined.

Example 2 Instead of 80 parts of phenol novolak type epoxy resin,
70 parts of phenol novolac type epoxy tree jII (manufactured by Tobu Kasei Co., Ltd., trade name YDPN638) and bisphenol type epoxy resin (manufactured by Shell Co., Ltd., trade name Epicote 828)
A conductive coating composition was obtained in the same manner as in Example 1 except that 10 parts was used, a coating film was obtained, and the physical properties of the coating film were measured. The obtained results are shown in Table 1.

Example 3 Instead of 80 parts of phenol novolac type epoxy resin,
L3-bis(N,N'-diglycidylaminomethyl)cyclohexane (manufactured by Mitsubishi Gas Chemical Co., Ltd., trade name TETRAD
A conductive coating composition was obtained in the same manner as in Example 1, except that 70 parts of -D) and 10 parts of a bisphenol-type epoxy resin (manufactured by Shell Co., Ltd., trade name Epicote 828) were used, and a coating film was obtained. The physical properties of the coating film were measured and the results are shown in Table 1.

Example 4 A conductive coating composition was obtained in the same manner as in Example 1 except that diphenyliodonium hexafluorofursenate was used in place of benzene-cyclopentadienyl-iron (■)-hexafluorophosphate, and @ The physical properties of the coating film were measured, and the results are shown in Table 1.

(Margin below) Table 1

Claims (1)

[Claims] 1. An epoxy resin having two or more epoxy groups in its molecule, containing a conductive powder whose main component is tin oxide and whose average particle size is 0.2 μm or less, and a curable catalyst. A conductive paint composition characterized by: 2. Claim 1, wherein the photocurable catalyst is selected from the group consisting of diaryliodonium salts, diarylsulfonium salts, and benzene-cyclopentadienyl-iron(II)-hexafluorophosphate. The conductive coating composition described in . 3. Claim 1, wherein the amount of the conductive powder added is 50 to 400 parts by weight per 100 parts by weight of the epoxy resin.
The conductive coating composition according to item 1 or 2.