JPS62195200A - Ag/ni covered cu powder - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] Technical Field> In recent years, computer equipment has been widely used, but
It has been pointed out that external electromagnetic waves affect computer equipment and cause malfunctions. This is because organic resin is used for computer housings, and radio waves can pass through organic resin. As a measure to prevent stiffness, organic resins are made conductive to provide an electromagnetic shielding effect.

The present invention relates to Cu powder coated with Ni and Ag, which is particularly suitable for mixing with organic resins to make the resins conductive.

<Conventional technology and its problems> How to make organic resin conductive ■Incorporating a conductive filler into the organic resin.

■Metallize the surface of the organic resin material by spraying metal zinc.

■Apply conductive paint to the surface of organic resin material.

The following methods are known, but the most widely used method is (2).

Conductive paint is made by containing conductive powder in the paint, but for the purpose of magnetic shielding, it must be highly conductive rather than for antistatic purposes, so Nj, CLI, etc. are used as conductive powder for filling. , Ag, etc. are used.

Among these, Ag has the highest conductivity and oxidation resistance, and does not deteriorate even if left for a long time, but it is expensive. Further, although Cu is inexpensive and has excellent conductivity, it is easily oxidized and lacks long-term durability. Although Ni is durable, it has poorer conductivity than Cu and Ag.

The present invention relates to conductive powder used in conductive paint, and relates to conductive powder used in conductive paint.
Its purpose is to improve the oxidation resistance and conductivity of

Attempts have been made to include antioxidants in paints for the purpose of improving the oxidation resistance of Cu, but organic substances are the main ingredient, and nothing is satisfactory. It is also known to coat Cu with Ag.
If it is coated with Ag, the amount of Ag coated will be large and the product will be expensive.

The present inventors investigated increasing the oxidation resistance by coating the surface of Cu powder with Ni. However, when coated with Ni, the oxidation resistance was equal to that of Nj, but the conductivity was lower than that of Cu.

Therefore, the present inventors were able to further increase the conductivity to the same level as AB and Cu by further coating a small amount of Ag on top of the Ni-coated Cu powder. That is, we have discovered an innovative powder that exhibits oxidation resistance with Ni and conductivity with Ag and Cu.

<Configuration of the Invention> According to the present invention, the core of the Cu particles and the first coating layer of Pd in an amount of 0.01 to 0.2% based on the weight of Cu], ~10.
A second coating layer of 0% Ni, a third coating layer of 0.2-5.0% Ag.
A Ag, Ni-coated Cu powder comprising a coating layer is provided.

Cu used in Ag, Ni-coated particles of the present invention
The particle size of the powder is not particularly limited, but is preferably from 0.5 to
It is 500μ, more preferably 1 to 100μ.

Purity is also not particularly limited.

The first layer of Pd is necessarily formed as a base for Ni plating, and has no positive meaning in the present invention.

The method of coating the Cu powder with Ni can be performed by a normal chemical plating method. That is, after depositing Pd on Cu powder, it is suspended in a Ni aqueous solution and a reducing agent such as hydrazine is added thereto, thereby causing Ni to precipitate on the surface of the Cu powder. Furthermore, coating with Ag can also be performed by chemical plating. That is, the desired powder can be obtained by suspending Ni-coated Cu powder in an ammoniacal Ag aqueous solution and adding a reducing agent such as formalin or tartaric acid.

The amount of Ni covered is 0.5 to 10ν relative to the weight of Cu.
t%. If it is less than 0.5 wt%, the Ni coating will not be complete and oxidation resistance cannot be maintained. Moreover, if it exceeds 10 wt%, the conductivity decreases and a large amount of Ag is required to be coated.

A suitable Ag coating is 0.2 to 5.0w 7%. 0.
If it is less than 2 wt%, the conductivity will be improved, and if it exceeds 5.0 wt%, the conductivity effect will hardly change.

It goes without saying that the powder according to the present invention can be used not only as a conductive filler for conductive paints used for electromagnetic shielding, but also as a filler for conductive pastes.

<Specific description of the invention> Example Cu powder (manufactured by Width Metal Haku Co., Ltd., particle size 3oμm) 10g
was immersed in a palladium chloride aqueous solution (0.3 g IQ concentration as Pd) to deposit Pd on the surface, then suspended in a nickel sulfate aqueous solution, and hydrazine (
0.5 to 4 g) was added and reacted for about 1 hour to precipitate Ni on the particle surface. The amount of Ni precipitation is 0.5~l Qwt
It was changed up to %. Next, this powder was collected and suspended in an ammoniacal silver nitrate aqueous solution, and hydrazine was added to it.
The powder from which g was precipitated was collected, washed with water, and dried.

The amount of Ag precipitated was varied from 0.2 to 5.0 wt%.

This powder was added to acrylic paint (Kansai Paint Co., Ltd. Acryk 200 resin 35 wt%, acetone, MEK, toluene mixed solvent 65 wt%), and using a homo mixer, 2
A conductive acrylic paint was prepared by dispersing it at 000r and pom for 15 minutes, and this was applied onto an acrylic plate to a thickness of 50 μm, and tests for electrical conductivity, oxidation resistance, etc. were conducted.

The results are shown in the table.

Table 0.5 0 1. I
XO,541,1Δ 1.0 3 1.1
02.0 0 3.0
02.00゜2 1.8
02.0 0.5 1.
2 02.0 1.0
1.1 02.0 5.
0 1.0 05.0
0 6 05.0
0.2 2.0 0
10.0 0 8
010.0 1.0 1.6
0 This result proves that the powder of the present invention is extremely superior to Cu powder as a conductive agent to be mixed into an organic resin.

Claims (1)

[Claims] 1. Nucleus of Cu particle and With respect to Cu weight First coating layer of 0.01-0.2% Pd 1-10.0% Ni second coating layer Third coating layer of 0.2-5.0% Ag Ag, Ni coated Cu powder consisting of.