JPS61285272A - Electrically conductive paint composition - Google Patents

Abstract

PURPOSE:To provide the titled composition composed of a specific acryl-modified chlorinated polyolefin copolymer and electrically conductive powder (or short fiber), and capable of imparting a polyolefin base with excellent adhesivity, water-resistance and shielding effect without using a primer treatment process. CONSTITUTION:The objective composition contains (A) a copolymer containing chlorinated polyolefin and obtained by polymerizing (i) a monomer mixture of 10-100(wt)% hydrogenated dicyclopentadiene derivative of formula (R is H or lower alkyl; R' is bivalent organic group; n is 0 or 1), 0-90% (meth)acrylic acid ester and 0-50% other copolymerizable vinyl monomer in the presence of (ii) a chlorinated polyolefin resin having a chlorine content of <=50% (the weight ratio of i/ii is 95/5-50/50) and (B) electrically conductive powder such as nickel powder or electrically conductive short fibers.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention applies to untreated polyolefin base materials such as molded products and films that have not been subjected to any surface treatment to impart paintability. , excellent adhesion and water resistance even without primer treatment.

The present invention relates to a conductive coating composition having a shielding effect.

(Prior Art) In recent years, as the density and performance of ICs and LSIs have increased, a large number of ICs and LSIs have come to be used in electronic devices. However, since high-frequency pulses are generated from these ICs and LSIs, surrounding televisions, radios, peripheral devices, etc. are affected by this, resulting in image distortion, noise, malfunction, etc., and this has become a problem. Furthermore, televisions, radios, and the like are similarly affected not only by high-frequency pulses from ICs and LSIs, but also by electromagnetic waves generated from automobiles, high-voltage lines, and the like. As the electromagnetic environment worsens year by year, there is an increasing need to shield electromagnetic waves, and laws and regulations have been implemented in Europe and the United States, and even in Japan, it has become a two-hour problem to implement laws and regulations. .

As a method of shielding electromagnetic waves, there is a method of applying a conductive coating composition to the housing of an electronic device to protect it from electromagnetic waves that enter from the outside and to suppress electromagnetic waves generated from the device itself.

Conductive coating compositions generally include conductive powder and thermofusible acrylic resin, vinyl resin, or urethane resin.

Those dispersed in polyester resin, hydrocarbon resin, etc., or dispersed in thermosetting acrylic resin, unsaturated polyester resin, epoxy resin, silicone resin, etc. are known.

On the other hand, in various industrial fields, plastics are increasingly being used as housings for equipment in place of metals for weight reduction, rust prevention, and other purposes. For example, ABS resin and polystyrene resin are used for plastic molded housings for personal computers, CPU terminals, printers, VTRs, etc.

Modified polyphenylene oxide resin, polypropylene resin, polybutylene terephthalate resin, etc. are used. Among these, polyolefin resins such as polypropylene and polyethylene are expected to be frequently used due to their cost. However, a coating film obtained by applying the above-mentioned conductive coating composition to a molded article using this polyolefin resin generally has poor adhesion and water resistance. Therefore, in order to improve the adhesion and water-resistant coating performance to molded products using polyolefin resin, many attempts have been proposed, and surface treatment methods and improvements in resin adhesion have been investigated. ing.

For example, there is a method of improving adhesion by subjecting the surface of these molded products to surface treatments such as degreasing treatment and chromic acid treatment.

In addition, there is a method in which a chlorinated polyolefin or a polyolefin modified with maleic acid or its anhydride is applied in a solution or dispersed state to the surface of the molded product, treated with a brimer, and then a paint with excellent film performance is applied. (For example, Japanese Patent Publication No. 44-985, Japanese Patent Publication No. 53-47828)
No. 53-114874, Japanese Patent Application Laid-Open No. 1983-114874
-15976 publication, JP-A-55-48260 publication,
JP-A-55-148156, JP-A-58-830
42, 2% (see JP-A-58-118809, JP-A-59-30830, etc.).

On the other hand, as a coating composition that improves the adhesion of paint films to molded products using polyolefin resin.

A composition comprising an epoxy resin, a curing agent for the epoxy resin, and a polyolefin or ethylene copolymer having a functional group that reacts with the epoxy group has been proposed (for example, Japanese Publication No. 52-47.487).

JP-A-52-139142, JP-A-56-764
Publication No. 33, JP-A-56-72053, JP-A-5
6-50971, JP-A-58-101122, etc.). Furthermore, compositions made of an acrylic resin having a functional group that reacts with an NCO compound and a chlorinated polyolefin, and compositions made of a chlorinated polyolefin-modified acrylic resin having a functional group that reacts with an NCO compound have been proposed (for example, Special Publication No. 57-14767,
JP-A-58-17174 2% JP-A-59-2796
(See Publication No. 8, etc.) Furthermore, acrylic modified chlorinated polyolefin resin compositions comprising an acrylic resin and a chlorinated polyolefin have been proposed (for example, Japanese Patent Laid-Open No. 58-7
Publication No. 1966.

JP-A-58-83042 2% JP-A-58-1762
Publication No. 07 9% Publication No. 1988-176208, Publication No. 58-173113 2% Publication No. 188-183718
No. 194959, JP 58-194959, JP 59 Sho 59
-Refer to Publication No. 30830, etc.).

(Problems to be Solved by the Invention) However, the surface treatment method described above cannot sufficiently improve coating film performance such as adhesion. In addition, with the method of applying the primer treatment described above, depending on the type of chlorinated polyolefin or modified polyolefin, a coating film with excellent adhesion can be obtained, but the procedure for applying the primer is complicated, and the primer treatment is complicated. The disadvantages are that the treatment requires a lot of time and effort, and the coating cost increases. Furthermore, it cannot be said that the above-mentioned epoxy compositions and urethane compositions have sufficient adhesion to polyolefin base materials. Also.

Since it is a two-part type, it takes time to mix.

Since it is a hardening type, there are drawbacks such as pot life and workability must be taken into consideration.

In addition, the adhesion of the acrylic-modified chlorinated polyolefin composition is affected by the amount of chlorinated polyolefin,
When trying to obtain sufficient adhesion.

Performance such as appearance and gloss of resin deteriorates. Therefore.

The drawback is that it is impossible to adjust properties such as adhesion, resin appearance, and gloss.

The present invention solves the above-mentioned drawbacks, and can be applied directly onto molded products using polyolefin resin without surface treatment, and has excellent adhesion, water resistance, and shielding properties to the molded products. An object of the present invention is to provide a conductive coating composition.

(Means for solving problems) The present invention is.

(A) In the presence of a chlorinated polyolefin resin having a chlorine content of 50% by weight or less.

Shin) General formula: [In the formula, R represents hydrogen or a lower alkyl group, and R' is 2
10 to 100% by weight of a hydrogenated dicyclopentadiene derivative
and.

(b) 0 to 90% by weight of acrylic ester and/or methacrylic ester.

(C) 0 to 50% by weight of another vinyl monomer copolymerizable with the above (a) and (b).

The total amount of (a), (b) and (C) above is 100% by weight
As.

and (B) a chlorinated polyolefin-containing copolymer obtained by polymerizing the chlorinated polyolefin resin and the monomer at a weight ratio of 5:95 to 50:50. The present invention relates to a conductive coating composition containing conductive powder or conductive short fibers.

Examples of the chlorinated polyolefin resins having a chlorine content of 50 weight or less include polyethylene resins, polypropylene resins, ethylene-propylene copolymers, and ethylene-vinyl acetate copolymers having a chlorine content of 50 weight or less. etc. are used. If the chlorine content exceeds 50% by weight, the adhesiveness to the polyolefin base material will decrease. The chlorine content should be determined taking into account various coating properties, and is preferably between 15 and 35% by weight.

(In the hydrogenated dicyclopentadiene derivative which is the al component, (0-R')n OCC=CH2 is at the 8th or 9th position
It is connected to the position. π is a divalent organic group, but preferably has 1 to 18 carbon atoms from the viewpoint of adhesion to the base material.
or an alkylene group of the formula -(f-o>m-R, - (wherein Pi and R are the same or different, represents an alkylene group having 2 or more carbon atoms, and 9m represents an integer of 1 or more) A group is used.

Hydrogenated dicyclopentadiene derivatives include tricyclodecyl acrylate, tricyclodecyl methacrylate, tricyclodecyloxyethyl acrylate),) tricyclodecyloxyethyl methacrylate, tricyclodecyloxypropyl acrylate, tricyclodecyloxy Examples include tricyclodecyloxyalkyl acrylate or methacrylate such as methacrylate, acrylate or methacrylate of polyalkylene glycol tricyclodecyl monoether such as acrylate or methacrylate of diethylene glycol tricyclodecyl monoether, and the like.

Regarding the amount of the hydrogenated disypolopentadiene derivative,
If this is less than 10% by weight, it is water resistant.

10 to 100% by weight, as gloss, resin appearance, etc. are reduced.
Preferably it is used in an amount of 20 to 100% by weight.

The acrylic ester or methacrylic ester as component (b) includes alkyl acrylates such as methyl acrylate, ethyl acrylate, butyl acrylate, isbutyl acrylate, 2-ethylhexyl acrylate, lauryl acrylate, methyl methacrylate, Examples include alkyl methacrylates such as ethyl methacrylate, butyl methacrylate, isobutyl methacrylate, 2-ethylhexyl methacrylate, and lauryl methacrylate, cyclohexyl acrylate, and cyclohexyl methacrylate.

When using these, either one type or two or more types may be used. 2-hydroxyethyl methacrylate, 2-hydroxyethyl acrylate, hydroxyglopyr methacrylate.

Polymerizable monomers containing functional groups such as hydroxyl groups, glycidyl groups, carboxylic acid groups, amine groups, etc., such as hydroxypropyl acrylate, glycidyl methacrylate, glycidyl acrylate, methacrylic acid, acrylic acid, methacrylamide, and acrylamide, are May be used in combination. If these esters are used in excess of 90% by weight, the appearance of the resin and gloss will be reduced.

Since water resistance etc. decrease, the amount used is limited to 90% by weight or less.

The above (a) hydrogenated dicyclopentadiene derivative and (b)
) Component (C), which is another vinyl monomer copolymerizable with acrylic ester and/or methacrylic ester, includes styrene, or unsaturated dibasic acids such as phthalic acid and maleic acid and their esters; Examples include vinyl derivatives such as vinyl chloride and vinyl acetate. If these vinyl monomers are used in an amount exceeding 50% by weight, the resin will become cloudy, so they are used in an amount of 50% by weight or less.

In the present invention, the weight ratio of the chlorinated polyolefin resin and the monomer is 5:95 to 50.
: Polymerization is carried out at a ratio of 50. If this weight ratio exceeds 50:50, solvent resistance and hardness will decrease.

Furthermore, if the weight ratio is less than 5:95, the adhesion to the polyolefin substrate will decrease. This weight ratio is 1
Preferably, the ratio is 0+90 to 35:65.

The conductive powder of the present invention includes carbon, nickel, copper,
Powders such as silver are used. In the case of a coating composition for electromagnetic shielding, it is preferable to use powders of nickel, copper, silver, etc. The nickel powder may be either needle-like crystals or flake-like crystals, and its trade name is Type 123°255.287. manufactured by Inco. Novamet H
Examples include CA-1°HCT. Further, nickel-plated mica powder or organic fiber powder may be used as the nickel powder. Copper powder and silver powder are also acicular.

Either resin-like or flake-like crystals may be used.

Examples of the copper powder include 115 series manufactured by Shushu Metal Foil and Powder Industries Co., Ltd. and atomized copper powder manufactured by Mitsui Kinzoku Kogyo Co., Ltd.

Examples of silver powder include the Silcoat series manufactured by Hakushu Metal Foil and Powder Industries Co., Ltd. Furthermore, copper powder plated with silver may be used, and short fibers such as polyester short fibers and nickel may be used.

Short fibers plated with copper, silver, etc. and preferably having a fiber length of 1 mm or less are used. Two or more types of these powders or short fibers may be used in combination. Also.

Fillers such as silicon oxide, titanium oxide, calcium carbonate, magnesium carbonate, and silicone oil are used as paint additives to impart chicken properties.

Silicone coupling agents, ionic surfactants, etc. may also be used. In addition, as a diluting solvent, toluene, xylene, acetone, methyl ethyl ketone, methyl isobutyl ketone, methyl alcohol, ethyl alcohol, and ethyl selonol.

Commonly used solvents such as butylceronlube and aliphatic solvents are used.

The blending ratio of the resin and the conductive powder used in the present invention is preferably 100 to 600 parts by weight of the conductive powder per 100 parts by weight of the chlorinated polyolefin-containing copolymer. If the amount of conductive powder is less than 100 parts by weight, the conductivity tends to decrease.
If it exceeds 600 parts by weight, it becomes difficult to form a paste, resulting in poor coating workability and film-forming properties, and the painted surface of the plastic molded product tends to become rough.

Further, when paint additives are used, the amount added thereof is preferably about 0.1 to 5% by weight based on the paint composition. There is no limit to the mixing ratio of the diluting solvent, but in order to reduce sedimentation of the filler, it is preferable that the amount added is small.

(Effects of the Invention) When the conductive coating composition of the present invention is applied to a polyolefin resin molded article, the adhesion, water resistance, and A housing with excellent shielding effect can be obtained.

(Example) The present invention will be described in detail.

Example 1 220 parts by weight of chlorinated polypropylene (a toluene solution with a chlorine content of 26% by weight and a solid content of 15% by weight) was placed in a reactor equipped with a stirrer and a cooler.

It was heated to 100°C, and 75 parts by weight of methyl methacrylate, 25 parts by weight of tricyclodecyl methacrylate (manufactured by Hitachi Chemical Co., Ltd., FA-513M) and 1 part by weight of benzoyl peroxide were uniformly dissolved therein. Add the lysate dropwise over 3 hours.

The same temperature was maintained for 5 hours to obtain an acrylic-modified chlorinated polypropylene resin with a nonvolatile content of 42.2% by weight.

Next, 100 parts by weight of the resin obtained above was added with nickel powder (carbon nickel φ287°, average particle size 4.
0 micron) 160 parts by weight, methyl in butyl ketone 3
5 parts by weight were mixed and stirred to obtain coating composition 1. The viscosity of this paint composition 1 was adjusted using thinner so that it would last for 15 seconds in a 7-odd cup, and the viscosity was adjusted to "Noblen BC3BJ (
Manufactured by Mitsubishi Yuka Co., Ltd., untreated polypropylene, thickness 2mm
It was spray-painted on a molded plate (size: Xf50 x 150mm) and dried at 60°C for 15 minutes. The coating film thus obtained was evaluated for adhesion, water resistance, and shielding effect. The results are shown in Table 1.

Example 2 Chlorinated polypropylene (chlorine content 26% by weight, solid content 15% by weight) 2 was placed in a reactor equipped with a stirrer and a cooler.
Add 20 parts by weight and heat to 100°C, and add tricyclodecyl methacrylate (manufactured by Hitachi Chemical Co., Ltd.,
FA-513M) 100 parts by weight and 1 part benzoyl peroxide
A melt obtained by homogeneously dissolving parts by weight was added dropwise over 3 hours and maintained at the same temperature for 5 hours to obtain a hydrogenated dicyclopentadiene-modified chlorinated polypropylene resin with a nonvolatile content of 42-1% by weight.

Next, to 100 parts by weight of the resin obtained above, 100 parts by weight of nickel powder (carbonyl nickel φ255, average particle size 3.0 microns, manufactured by Shushu Metal Foil Industry ■) was added.

40 parts by weight of copper powder (115-A manufactured by Shushu Metal Foil & Powder Industry ■),
Silicon oxide powder (Erosil 38 manufactured by Nippon Aeroseal Co., Ltd.)
0) Mix and stir 0.5 parts by weight and 30 parts by weight of toluene,
Paint composition 2 was obtained. Next, the viscosity was adjusted and the coating and drying were carried out in the same manner as in Example 1, and the coating film was evaluated in the same manner. The results are shown in Table 1.

Example 3 Chlorinated polypropylene (chlorine content 26% by weight, solid content 15% by weight) 3 was placed in a reactor equipped with a stirrer and a cooler.
7 parts by weight, 27.5 parts by weight of chlorinated polyethylene (chlorine content 26%, solid content 20%) and 75 parts by weight of toluene were heated to 80°C, and 55 parts by weight of methyl methacrylate was added thereto.
Parts by weight, 20 parts by weight of Ibutyl methacrylate, Tricyclodecyl methacrylate (manufactured by Hitachi Chemical Co., Ltd., F
A-513M) 25 parts by weight, 1 part by weight of benzoyl peroxide, and 38 parts by weight of toluene were uniformly dissolved and the resulting solution was added dropwise over 3 hours and maintained at the same temperature for 10 hours until the non-volatile content was 41.5 parts by weight. - acrylic modified chlorinated polyolefin was obtained.

Next, to 100 parts by weight of the resin obtained above, nickel-plated mica powder (manufactured by Nopco Co., Ltd., average particle size 0.2 on
50%, specific gravity 4.1), 50 parts by weight of nickel powder (Carbonyl Ni Φ255 manufactured by Fukushu Metal Foil & Powder Industry ■), and 30 parts by weight of methyl isobutyl ketone were mixed and stirred to obtain coating composition 3. Next, the viscosity was adjusted and the coating and drying were carried out in the same manner as in Example 1, and the coating film was evaluated in the same manner.

The results are shown in Table 1.

Comparative Example 1 Acrylic-modified chlorinated polypropylene with a nonvolatile content of 42.0% by weight was obtained in the same manner as in Example 1, except that 25 parts by weight of butyl methacrylate was used instead of tricyclodecyl methacrylate in Example 1. Then, coating composition 4 was obtained in the same manner as in Example 1. Next, the viscosity was adjusted and the coating was applied and dried in the same manner as in Example 1, and the coating film was evaluated in the same manner. The results are shown in Table 1.

Comparative Example 2 In Example 1, chlorinated polypropylene was not used, but 87 parts by weight of toluene was added, heated to 100°C, and 75 parts by weight of methyl methacrylate was added thereto.

A solution obtained by uniformly dissolving 25 parts by weight of tricyclodecyl methacrylate, 63 parts by weight of toluene, and 1 part by weight of benzoyl peroxide was added dropwise over 3 hours, and the mixture was heated to the same temperature for 5 minutes.
After holding for a period of time, an acrylic resin with a non-volatile content of 40.5 cm was obtained. Furthermore, coating composition 5 was obtained in the same manner as in Example 1.

Next, the viscosity was adjusted and painted in the same manner as in Example 1.

After drying, the coating film was evaluated in the same manner.

The results are shown in Table 1.

The coating film performance was measured as follows.

Adhesion: Based on JIS K 5400 cross-cut Sellotape test method.

Water resistance: 72 at humidity of 95 degrees or higher and temperature of 50 degrees Celsius
The appearance after standing for a period of time was visually evaluated and indicated by the following symbols.

◎ No abnormality ○ Slightly blurred and flaky Slightly blurred and peeled Shielding effect: The shielding effect was measured using a spectrum analyzer manufactured by Takeda Riken Kogyo ■.

Table 1 Adhesion of the conductive coating composition of the present invention.

A coating film with excellent water resistance and shielding effect can be obtained.

H method: 9-

Claims (1)

[Claims] 1. (A) In the presence of a chlorinated polyolefin resin with a chlorine content of 50% by weight or less, (a) General formula: ▲There are mathematical formulas, chemical formulas, tables, etc.▼ [In the formula, R is Represents hydrogen or a lower alkyl group, R' is 2
10 to 100% by weight of a hydrogenated dicyclopentadiene derivative represented by a valent organic group, and n is 0 or 1.
(b) 0 to 90% by weight of acrylic ester and/or methacrylic ester; (c) 0 to 50% by weight of another vinyl monomer copolymerizable with (a) and (b) above. The total amount of (a), (b) and (c) is 100% by weight, and the weight ratio of the chlorinated polyolefin resin and the monomer is 5:95 to 50:50. An electrically conductive coating composition comprising a chlorinated polyolefin-containing copolymer obtained by polymerization at a ratio of (B) electrically conductive powder or electrically conductive short fibers.