JPH0635675B2 - Resin composition for electric plating - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a resin composition for electric plating, and for example, to a composition that can be used for electric devices, automobiles and the like.

(Prior Art) In recent years, research and development of plastic materials as alternative materials for various metal products have been active. In particular, there is a strong need for light, thin, short, and small products in the fields of electric and electronic devices and automobiles, and many plastic materials have been developed. However, plastic materials still have many drawbacks in terms of chemical resistance or heat resistance and weather resistance. Therefore, in many cases, by applying a metal coating on the surface of a plastic material, these defects are used to the full extent. The method of applying a metal coating to the surface of a plastic product can be roughly classified into a wet method and a dry method. Among these methods, the method that has recently made rapid progress is the dry method, and the chemical vapor deposition method (CVD), physical vapor deposition method (PVD), ion plating method, and the like are well known, but all of them are batch production systems and equipment. Due to the high cost, the wet method has not been developed yet.

The wet method is a metal coating method using a so-called plating method. Since conventional plastic materials are themselves electrically insulating materials, conduction is not recognized, and electroless plating is becoming popular. However, electroless plating in plastic materials has many problems such as high processing cost and insufficient adhesion to plastic materials. Therefore, knead the conductive material with the plastic material,
By imparting conductivity to the plastic material and making electroplating with respect to these conductive plastics, the conventional defects could be greatly improved. Here, the conductive substance is a conductive carbon black,
Conductive carbon fibers and various metal fibers have been put to practical use. However, these known conductive materials also have various drawbacks. That is, the characteristics of the conductive plastic material having good plating characteristics are generally listed as follows.

High conductivity of 5 × 10 ¹ Ωcm or less Smooth surface of molded product molded with composition Durability in heating / cooling cycle Dimensional stability of molded product molded from resin composition First, the composition of which conductivity is imparted by the conductive carbon black is sufficient. However, if the carbon black is highly filled, the physical properties of the plastic are greatly reduced, It is not the best in terms. Next, the composition in which the conductivity is imparted by the conductive carbon fiber is filled with the carbon fiber at a high level,
The condition of can be satisfied to some extent, and the condition of is not a problem. However, the above condition is not sufficient, and extremely high filling is required to satisfy the condition, and high filling of an expensive carbon fiber is economically extremely limited in application and versatile. Finally, with regard to metal fibers, by filling the metal fibers with a high degree, it is possible to satisfy a certain degree, but it is extremely poor, and the high filling of the metal fibers loses the plasticity of the plastic, and it is practical. Currently, it is rarely used.

(Problems to be Solved by the Invention) An object of the present invention is to provide a composition having high conductivity, in which a molded article obtained from the composition has a smooth surface and is durable in a heating / cooling cycle, Moreover, it is an object of the present invention to provide a resin composition for electric plating, which can give a molded product having high dimensional stability.

(Means for Solving Problems) The present invention relates to a resin for electric plating containing a thermoplastic resin and a conductive alkali metal titanate, which has a high volume conductivity of 5 × 10 ¹ Ωcm or less. It relates to the composition.

In the present invention, the volume resistivity is obtained by the following formula, and is not the measuring method itself of JIS K6911 (based on ASTM D-257) but simply based on the following formula: sheet thickness × electrode length (sheet width) (Equal to) and the cross-sectional area, the distance between the electrodes is considered as the thickness according to the JIS method, and the electrical resistance is measured to obtain the volume resistivity.

A feature of the present invention is that a conductive alkali metal titanate is used as a conductive substance of a resin composition for electrical plating. The conductive alkali metal titanate referred to in the present invention is as follows. That is, 1) General formula M ₂ O.aTiOx.bH ₂ O (where M is L
Alkali metal such as i, Na, K, 0 <a ≦ 8, 0 ≦ b
≦ 4, 0 <x <2, a, b, and x are real numbers), and the conductive alkali metal titanate (I) 2) general formula M is generally called reduced alkali metal titanate or bronze alkali metal titanate. ₂ O · aTiOy · bH ₂ O (M in the formula,
a and b are the same as described above, and are represented by 0 <y ≦ 2). Conductive alkali metal titanate (II) in which a dissimilar metal compound is fixed or solid-solved on the surface of alkali metal titanate 3) Conductive alkali titanate Conductive alkali metal titanate (III) obtained by further reducing metal (II), and the like.
It is a species or a mixture of two or more species.

The conductive alkali metal titanate of the present invention has the general formula M ₂
O _· aTiO 2 _{· bH} 2 O The alkali metal titanate represented by (wherein M, a, b as defined above is) (IV) is distinguished.

Generally, alkali metal titanate (IV) is obtained as a fibrous single crystal and is excellent as a heat-resistant and reinforcing filler, but it is an electrical insulator, and alkali metal titanate (IV) alone However, a composition exhibiting conductivity cannot be obtained.

Regarding the conductive alkali metal titanate in the present invention, the present inventor has already proposed a method for producing a conductive alkali metal titanate (I) from an alkali metal titanate (IV), an alkali metal titanate (IV) or a conductive titanium. Acid alkali metal (I)
We have developed a technology such as a method for producing conductive alkali metal titanate (II) from, and a method for producing conductive alkali metal titanate (III) from conductive alkali metal titanate (II), and have applied for a patent. (For example, JP-A-58-135129,
58-135130 and 59-102820). However, the conductive alkali metal titanate of the present invention is not limited to those described in these patents.

The conductive alkali metal titanate used in the present invention is a conductive material having excellent reinforcing properties and heat resistance, and the production method of the conductive alkali metal titanate (I) is exemplified.

The conductive alkali metal titanate (I) is prepared by reducing the alkali metal titanate (IV) in a reducing atmosphere, for example, a reducing gas atmosphere such as H ₂ or CO, or a non-oxidizing atmosphere in the presence of a reducing agent such as a carbon material. It can also be directly produced by a method of heat treatment at 500 ° C. or higher, or by a reducing atmosphere or a non-oxidizing atmosphere in the presence of a reducing agent during the production of the alkali metal titanate (IV). In addition, the general formula M ₂ O.aTiOx.
In the alkali metal titanate represented by bH ₂ O (M, a, b, and x are the same as those described above), M is potassium, that is, reduced potassium titanate changes its color tone with the change of x, and is white-purple, It changes to purple, black, black purple, gold, silver white, but as the conductive alkali metal titanate (I) of the present invention, x ≦ 1.99, preferably x
From the viewpoint of conductivity, those reduced to a light purple color of <1.95 and showing a black color or more are preferable. The conductive alkali metal titanate of the present invention includes all of the conductive alkali metal titanate (I) to (III) or a mixture of two or more thereof and the reinforcing or non-reinforcing conductive alkali metal titanate. However, a fine fibrous material is preferable from a practical point of view, and usually has a fiber diameter of 0.1 to 1 μm and an aspect ratio of 1.
Those having a value of 0 or more are preferable from the viewpoint of imparting a surface smoothness with a reinforcing effect. Also, the selection of the conductivity of these conductive alkali metal titanates should be selected according to the purpose of use,
The conductivity of the conductive alkali metal titanate in the present invention is preferably 10 ⁻¹ to 10 ⁻² Ωcm in volume resistivity.

The thermoplastic resin in the present invention is a thermoplastic resin having a metal-replacement performance by blending a fibrous filler, and is generally called engineering plastics. In the present invention, fiber-reinforced general-purpose resin compositions such as fiber-reinforced polypropylene and fiber-reinforced ABS resin are also referred to as engineering plastics and are included as the thermoplastic resin of the present invention, but other polyacetals, polycarbonates, polyethylene terephthalates, polybutylene terephthalates, polyphenylenes are also included. Anylensulf eyed,
Polyphenylene oxide, polyamide and the like can be mentioned, and further, polyimide called super engineering plastics, polyamide imide, bismaleimide triazine resin, polyarylate and the like are thermoplastic resins which can be adopted.

In the present invention, the volume resistivity of the resin composition obtained by blending the conductive alkali metal titanate with the thermoplastic resin as described above may be 5 × 10 ¹ Ωcm or less. On this occasion,
The amount of the conductive alkali metal titanate added to the thermoplastic resin in the present invention may vary depending on the type of the thermoplastic resin, but is generally 20 to 50% by weight, preferably 30.
-40% by weight. When the content of the conductive alkali metal titanate is less than 20% by weight, the conductivity required for electric plating cannot be obtained, and when the content exceeds 50% by weight, there is a problem in workability and moldability. It has a poor appearance and is not suitable for the purposes of the invention.

In the present invention, other inorganic fillers such as glass fiber, carbon fiber, asbestos, carbon black and the like may be further mixed in a range that does not deteriorate physical properties such as adhesion and appearance.

The composition of the present invention can be obtained by blending a conductive alkali metal titanate with a thermoplastic resin, and as the mixing method, any conventionally known mixing method can be used, and an extruder, a mixing roll, a kneader and the like can be mentioned. But you can
Among these, the most suitable mixing method is to use a twin-screw kneading extruder. The resin composition for electrical plating of the present invention thus obtained is molded into a molded article having a desired shape, and the molding method may be injection molding, compression molding, extrusion molding, or any other commonly used method. To be

As a method of applying electrical plating to the molded product, a conventionally known method can be adopted, and no special device or chemical is required.

(Examples) Hereinafter, the present invention will be described in more detail with reference to Examples.
The invention is not limited by these examples. In the examples, "parts" and "%" mean "parts by weight" and "% by weight" unless otherwise specified.

Example 1 Conductive potassium titanate fiber having a volume resistivity of 10 ⁻² Ωcm itself [fiber diameter 0.2 to 0.5 μm, fiber length 10 to 1]
5 μm, Otsuka Chemical Co., Ltd., trade name, Teismo BK-3
00] to the thermoplastic resin shown in Table 1 in a twin-screw kneader (4
5φ) was kneaded to prepare a resin composition for electric plating of the present invention. The composition thus obtained was added to 150
Tongue injection molding machines were used to prepare dumbbell test pieces, and various mechanical and thermal properties were measured. Further, the composition was supplied to a press machine to prepare a sample for measuring electrical characteristics, and the electrical characteristics were measured by the method described below. That is,
A mold was placed on a polytetrafluoroethylene sheet and press-molded into a shape having a thickness of 6 mm, a width of 2.0 cm and a length of 10.0 cm to prepare a sheet-shaped sample having a width of 2.0 cm and a length of 10.0 cm. . The thickness was measured with a micrometer having an accuracy of 0.01 mm. After crimping silver foil on both ends and cross section of the above sample,
Attach a silver electrode to the surface of the silver foil and set the gap between the two electrodes to 1
Digital multimeter TR-6841 as 0.0cm
(Takeda Riken) was used to measure the electrical resistance between the two electrodes, and the volume resistivity was calculated from the following equation.

Under the above measurement conditions, the length of the electrodes and the distance between the electrodes are 2.0 cm and 10.0 cm, respectively.

In the table, PP is polypropylene, ABS is acrylonitrile-butadiene-styrene copolymer, POM
Is polyoxymethylene (including modified products), PBT is polybutylene terephthalate, Izod impact value is measured with notch, heat deformation temperature is bending stress 18.5 kg / c
It was measured under a load such that m ² was obtained.

Example 2 The resin composition for electric plating obtained in Example 1 was molded at a molding temperature of 190 to 2 using a screw-in-line type injection molding machine.
At 50 ° C., a rectangular test piece having a thickness of 3 mm, a length of 65 mm, and a width of 50 mm was formed, treated according to a conventional method, and electroplated. That is, the above test piece was subjected to alkaline degreasing at 50 ° C. for 3 minutes according to a conventional method, washed with water at room temperature to neutralize the test piece, and then the Ni-Co strike plating (pH 4.2, 50 to 60 ° C.). Liquid temperature, 1V → 1 minute, 2V
→ 3 to 6 minutes, 3 A / dm ² → 3 to 5 minutes), and then about 3 μm of plating is performed, and then plating is performed by the same process as general ABS plating (copper sulfate plating-bright nickel plating-chrome plating). I got a finished product. The four types of test pieces molded in Example 2 were molded articles that were extremely smooth and had a smooth appearance.

In addition, the evaluation of the moldability to the molded product was measured by the following method, and the results are shown in Table 2.

1) Hardness of the surface of the plating layer The hardness of the surface of the plating layer was measured using a Micro-Hitzkers hardness tester with a load of 20 g.

2) Glossiness of the surface of the plating layer A variable-angle photoelectric glossmeter (TC-105, manufactured by Tokyo Koden) was used to measure the incident and received light angles of 20 ° and the reflectance (%) of the surface mirror was used.

3) Abrasion test In order to measure the resistance value to the rough wear of the plated layer, the ASTM-D1242A method (JISK-7205) is used.
Using a rough wear tester, the rate of peeling (wearing) of the plating layer was measured.

4) Tensile bond strength In order to measure the bonding force between the mated layer and the material to be mated, bond the mated layer of the test piece and the jig with an epoxy resin adhesive to obtain tensile stress perpendicular to the mated layer. The tensile stress (tensile bond strength) when peeled off was measured.

5) Thermal cycle test This test tests the state of shear peeling caused by the difference in thermal expansion between the plated layer and the material to be plated.
× 120min → room temperature × 30min → -20 ° C × 60m
in-room temperature x 30min heating / cooling thermal cycle test 5
Cycles were performed to observe the occurrence of abnormalities in the plating layer of the test piece.

(Effects of the Invention) The resin composition for electric plating of the present invention has the following excellent features.

The conductivity of the composition of the present invention is extremely stable, and the control of the plating bath is extremely easy.

The surface of the molded product obtained by molding the composition of the present invention is extremely smooth, and the gloss of the plating layer can be easily obtained.

Since the physical and mechanical properties of the composition of the present invention are extremely excellent, the physical properties of the matted product are also excellent, the adhesion is excellent, and the durability is also excellent.

Therefore, it can be used in a very wide range of applications as a plastic product for plastics.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Masayoshi Suzue Inventor Masayoshi Suzue 463, Kagasuno, Kawauchi-cho, Tokushima City Tokushima Plant, Otsuka Chemical Co., Ltd. Tokushima Plant, Tsuka Chemical Co., Ltd. (72) Minoru Takenaka, 10 Bungo-cho, Higashi-ku, Osaka-shi, Osaka Otsuka Chemical Co., Ltd. (56)

Claims (4)

[Claims] 1. A resin composition for electrical plating containing a thermoplastic resin and a conductive alkali metal titanate, which has a high conductivity with a volume resistivity of 5 × 10 ¹ Ωcm or less. 2. The composition according to claim 1, wherein the conductive alkali metal titanate has a volume resistivity of 10 ⁻¹ to 10 ⁻² Ωcm. 3. The composition according to claim 1, wherein the conductive alkali metal titanate has an aspect ratio of 10 or more. 4. The content of conductive alkali metal titanate is 2
A composition according to claim 1 which is 0 to 50% by weight.