JPH055262B2 - - Google Patents

Description

[Detailed description of the invention]

[Technical Field of the Invention] The present invention relates to a conductive resin composition with good dispersion of copper powder and excellent resistance stability. [Technical background of the invention and its problems] In recent years, the development of ICs, LSIs, etc. has been remarkable, and their density and performance have increased, and electronic devices include a large number of ICs,
LSI has been used. However, since high-frequency pulses are generated from ICs and LSIs, surrounding computers, televisions, radios, etc. can be affected, causing malfunctions and
This has caused problems such as image distortion, noise, and similar effects from electromagnetic waves generated from other sources. In order to cope with the electromagnetic wave environment that is worsening year by year, laws in the United States (FCC regulations), West Germany (FTZ regulations), etc. require electronic devices to be shielded from electromagnetic waves. As a method for shielding electromagnetic waves, there is a method of applying conductive paint or conductive adhesive to the housing of an electronic device. These conductive paints and adhesives are made by dispersing and blending conductive powder into resin. However, conductive powder has a small bulk specific gravity, so in order to make it uniformly dispersed in the resin, it must be dispersed using a mixer such as a dispersion mill or colloid mill, but since the conductive powder is composed of different substances, it is difficult to obtain a homogeneous dispersion. There are no drawbacks. Furthermore, even if dispersed, the conductive powder has the disadvantage that it settles to the bottom of the container over time. The precipitated material coagulates tightly, and when used as a paint, it is difficult to loosen and redisperse it. Furthermore, conductive powders, especially copper powders, are not stable when used as paints or adhesives because the surface of the powders is oxidized by moisture and the like, increasing the resistance value. As a result, there is a drawback that the conductivity decreases over time and the conductivity deteriorates. In order to improve these, there is a method of treating metal powder with alkyl fatty acids (Japanese Patent Application Laid-Open No. 135495/1982), a method of adding a cationic antistatic agent along with conductive powder (Japanese Patent Application Laid-open No. 32668/1983), and organic titanates. and a method of adding fine silica (Japanese Patent Application Laid-open No. 56-36553)
etc. have been proposed. However, none of these are sufficient, and there has been a demand for the development of a material with good dispersibility and good resistance stability. [Object of the Invention] The present invention was made in order to eliminate the above-mentioned drawbacks, and an object of the present invention is to provide a conductive resin composition in which copper powder is well dispersed and excellent in resistance stability. [Summary of the Invention] As a result of intensive studies to achieve the above object, the products of the present invention have been surface-treated with a 2-substituted-4,6-dithiol-sym-triazine derivative and treated with an organic titanium compound. It has been discovered that by adding and blending, a composition with good dispersion and oxidation prevention can be obtained, and as a result, excellent resistance stability can be obtained, leading to the present invention. That is, the present invention provides (A) a synthetic resin liquid (B) a 2-substituted-4,6-
Copper powder pretreated with dithiol-sym-triazine derivatives and (However, R in the formula is NHR′, NR′R″, OR′ or
SR', where R' or R'' is a hydrogen atom or an alkyl group having 1 to 18 carbon atoms, an alkylene group,
represents an aryl group, arylalkyl group, alkylaryl group or alkylenearyl group,
(M ¹ or M ² represents a hydrogen atom or an alkali metal atom); and (C) an organic titanium compound. Examples of the synthetic resin liquid (A) used in the present invention include thermoplastic acrylic resins, styrene resins, vinyl resins, alkyd resins, polyester resins, etc., and examples of thermosetting resins include epoxy resins, urethane resins, Examples include alkyd resins and unsaturated polyester resins, which may be used alone or in combination of two or more. The thermoplastic resin and the thermosetting resin may be used alone or in combination. These resins need to be liquids, or if they are solids themselves, they need to be dissolved in an appropriate organic solvent. The copper powder used in the present invention (B) pre-treated with the 2-substituted-4,6-dithiol-sym-triazine derivative represented by the above general formula () has a diameter of 20 μm.
The following fine powders are required. If it exceeds 20 μm, the bulk specific gravity becomes small and it becomes difficult to disperse, which is not preferable. The blending ratio of the copper powder varies somewhat depending on the purpose of use, but it is preferably in the range of (A) resin content/(B) copper powder = 6/4 to 1/9. Outside 6/4 the conductivity decreases,
If it is outside 1/9, it will not become paste-like and is not preferred. 2-Substituted-4,6 used in copper powder treatment in the present invention
Specific examples of -dithiol-sym-triazine derivatives include 2-methylamino-4,6-dithiol-sym-triazine, 2-ethylamino-4,6
-dithiol-sym-triazine, 2-amino-
4,6-dithiol-sym-triazine, 2-butylamino-4,6-dithiol-sym-triazine, 2-butylamino-4,6-dithiol-
sym-triazine monosodium, 2-octylamino-4,6-dithiol-sym-triazine 1/2 calcium, 2-octadecyl-4,6
-dithiol-sym-triazine, 2-diethylamino-4,6-dithiol-sym-triazine, 2-diethylamino-4,6-dithiol-
sym-triazine monosodium, 2-didodecylamino-4,6-dithiol-sym-triazine, 2-benzylamino-4,6-dithiol-sym-triazine monocalcium, 2-phenylamino-4,6-dithiol -sym-triazine monocalcium, 2-diphenylamino-
4,6-dithiol-sym-triazine, 2-naphthylamino-4,6-dithiol-sym-triazine, 2-naphthylamino-4,6-dithiol-sym-triazine monosodium, 2-morpholino-4,6 -dithiol-sym-triazine, 2-cyclohexyl-4,6-dithiol-
sym-triazine monosodium, 2-cyclohexylamino-4,6-dithiol-sym-triazine monosodium, 2-(β-carboxyl)ethylamino-4,6-dithiol-sym
-triazine, 2-(p-carboxyl)phenylamino-4,6-dithiol-sym-triazine, 2-methoxy-4,6-dithiol-sym-
Triazine, 2-phenoxy-4,6-dithiol-sym-triazine, 2-naphthoxy-4,6
-dithiol-sym-triazine, 2-thiobenzyloxy-4,6-dithiol-sym-triazine, 2-thiobutyl-4,6-dithiol-
Sym-triazine and the like can be mentioned. Moreover, potassium or sodium is preferable as the alkali metal, and calcium or magnesium is preferable as the alkaline earth metal. These derivatives may be used alone or in combination. As the organic titanium compound (C) used in the present invention,
Isopropyl trioctyl titanate, dicumyl phenyloxyacetate titanate, isopropyl tri(N-aminoethylaminoethyl) titanate, diisostearoyl ethylene titanate,
Examples include isopropyl tris (dioctyl pyrophosphate) titanate, bis (dioctyl pyrophosphate) ethylene titanate, and these may be used alone or in combination of two or more. The blending ratio of the organic titanium compound is based on the copper powder.
The content is preferably 0.01 to 2.0% by weight. If the blending amount is less than 0.01% by weight, the dispersion effect will be poor, and
If it exceeds 2.0% by weight, the dispersion effect will not be improved any further and, on the contrary, conductivity will be inhibited, which is not preferable. Copper powder with 2-substituted-4,6-dithiol-sym
- Surface treatment with triazine derivatives may be carried out by any known method, but 0.5 to 5% by weight of the derivative is dissolved in easily volatile alcohol such as ethyl alcohol, copper powder is added thereto, and the mixture is stirred for approximately 15 to 30 minutes. The copper powder may then be separated by filtration using a filter paper or the like or by a centrifuge. Thereafter, the alcohol adhering to the copper powder is dried to form a thin film of the 2-substituted-4,6-dithiol-sym-triazine derivative on the surface of the copper powder. If the derivative is adsorbed on the surface of the copper powder in advance, a strong thin film is formed, which blocks and protects the copper surface from the outside air and reduces the effects of oxidation and the like. The thin film formed here is estimated to have a thickness corresponding to 2 to 3 molecules of the derivative. The reason for this is that if the film is thicker than necessary, the conductivity will decrease even if the copper powders come into contact with each other. This thin film protects the copper powder and prevents it from being oxidized by outside air, moisture, etc. However, it has poor separation stabilizing effect in a resin solution. Therefore, by blending organic titanium compounds,
It is presumed that the organic titanium compound acts on the R portion of the derivative and improves its compatibility with the resin molecules, thereby increasing the dispersibility of the copper powder. The conductive resin composition of the present invention comprises (A) a synthetic resin liquid, (B) copper powder pretreated with a 2-substituted-4,6-dithiol-sym-triazine derivative, and (C) an organic titanium compound. Although the conductive composition is a diluent, a solvent such as toluene, xylene, acetone, methyl ethyl ketone, ethyl cellosolve, butyl acetate, cellosolve butyrate, etc. can be used. Further, finely powdered silica, talc, calcium carbonate, pigments, etc. can be added and blended as necessary. The conductive resin composition thus obtained is used as a paint adhesive for electronic and electrical parts. [Examples of the Invention] Next, the present invention will be specifically explained with reference to Examples, but the present invention is not limited to these Examples. Example 1 Pretreatment of copper powder 2-butylamino-4,6-dithiol-sym
- 1 kg of copper powder having an average particle size of 3 μm was added to a solution of 0.5 g of triazine dissolved in 1 part of ethyl alcohol with stirring, and the mixture was stirred for 30 minutes. The copper powder was then filtered off using filter paper. The copper powder was further washed once with acetone, followed by drying to remove the alcohol and acetone to obtain 2-butylamino-4,6-dithiol-
Copper powder treated with sym-triazine was obtained. 500g of treated copper powder and polymethyl methacrylate
150g of isopropyltrioctyl titanate was dissolved in 350g of a mixed solvent of toluene:butanol = 5:2 (weight ratio) and added to the solution while stirring with a high-speed stirrer, and then 0.05 parts by weight of isopropyltrioctyl titanate was added.
A conductive paint (A) was produced by stirring for a minute. Using this paint, the settling properties (dispersibility) and surface resistance of the coating film were measured, and the results are shown in Table 1. In the sedimentation test, a sample was placed in a 100 ml measuring cylinder, the stopper was placed, and the cylinder was allowed to stand. After a certain period of time, the depth of the cylinder supernatant was measured to test the stability of the dispersion. The surface resistance was determined by brushing the paint onto an ABS resin plate to a thickness of about 50 μm and leaving it for about 12 hours to dry the solvent to obtain a coating film. This coating film was measured using a commercially available resistance measuring device. Example 2 100 g of bisphenol A liquid epoxy resin, 10 g of dicyandiamide and methyl ethyl ketone
Add 30g and stir well. Meanwhile, water 1 to 2-
Dissolve 10 g of hexylamino-4,6-dithiol-sym-triazine monosodium, add 500 g of copper powder with an average particle size of 5 μm, stir for 1 hour, let stand, discard the supernatant, and add acetone. After adding and stirring, the copper powder was collected using a filter paper, and acetone was added thereon again to wash and dry the copper powder to perform copper powder treatment. 400 g of this copper powder was added to the epoxy resin with stirring, and then 8 g of isopropyl tris (dioctyl pyrophosphate) titanate was added as an organic titanium compound, and high-speed stirring was performed for 30 minutes to disperse the copper powder and form a conductive paint (B). I got it. The dispersibility of this paint was determined in the same manner as in Example 1.
The conductivity was determined by brushing the film onto a glass plate to a thickness of 40 μm and baking it to dry at 150° C. for 30 minutes, and then performing a surface resistance test on the film obtained. The results are shown in Table 1. Example 3 Dissolve 8 g of 2-phenylamino-4,6-dithiol-sym-triazine monosodium in 1 part of water, add 500 g of electrolytic copper powder with an average particle size of 5 μm, and stir well at 60° C. for 30 minutes. Next, it was filtered through a filter paper, and the filtered copper powder was washed once with 500 ml of water and once with acetone, and thoroughly dried to obtain treated copper powder. 500g of this treated copper powder, 25g of colloidal silica, and a copolymer of methyl methacrylate and butyl methacrylate, toluene:butanol=
1:1 (weight ratio) is added to 120 g of a 50 wt% solution of the solvent with high speed stirring, followed by isopropyl tri(N
-aminoethylaminoethyl) titanate 5g
In addition, the mixture was stirred for 30 minutes to obtain a conductive resin composition.
This composition was dissolved in a mixed solvent of ethyl acetate: toluene: isopropyl alcohol = 3:3:4 (weight ratio).
A conductive paint (C) was prepared by adding 50 g of the conductive paint (C), and various tests on dispersibility and surface resistance were conducted on this paint in the same manner as in Example 1. The results are shown in Table 1. Comparative Example 1 A conductive paint (D) was obtained in the same manner as in Example 1 except that copper powder not treated with the 2-substituted-4,6-dithiol-sym-triazine derivative was used. In addition, various properties were tested in the same manner and are shown in Table 1. Comparative Example 2 A conductive paint (F) was obtained in the same manner as in Example 2 except that no organic titanium compound was added. In addition, various properties were tested in the same manner and are shown in Table 1. Comparative Example 3 In Example 3, conductive paint ( ) was obtained. We also tested various characteristics in the same way, so the first
Shown in the table.

[Table] [Effects of the invention] As is clear from the above explanation and Table 1,
The conductive resin composition of the present invention has excellent dispersibility, and the copper powder never settles and solidifies at the bottom of the container, making it difficult to use, and the copper powder does not rust.
The surface resistance remained stable with little change even after heating and after the moisture absorption test, demonstrating the remarkable effects of the present invention.

Claims (1)

[Claims] 1 (A) Synthetic resin liquid (B) 2-substituted-4,6- represented by general formula ()
Copper powder pretreated with dithiol-sym-triazine derivatives and (However, R in the formula is NHR′, NR′R″, OR′ or
SR', where R' or R'' is a hydrogen atom or an alkyl group having 1 to 18 carbon atoms, an alkylene group,
represents an aryl group, arylalkyl group, alkylaryl group or alkylenearyl group,
(M ¹ or M ² represents a hydrogen atom or an alkali metal atom) (C) A conductive resin composition characterized by containing an organic titanium compound.