JP2546804B2 - Thermoplastic resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a thermoplastic resin composition containing a metal filler, which has excellent corrosion resistance and is suitable as a molding material for housings of electronic and electric devices, turntables, pulleys and the like. Regarding

(Prior Art) Mixing various shapes of metal filler into thermoplastic resin,
It has been widely practiced to impart conductivity or electromagnetic wave shielding property or to provide high specific gravity. For example, in JP-A-55-152743, "conductive resin composition", a conductive resin composition in which a fibrous conductive material such as a copper wire or an aluminum wire is mixed with a polyester resin, a phenol resin or the like is mentioned. Furthermore, the combined effect of metal powder is shown here. Further, in JP-A-58-78499, "Electromagnetic wave shielding resin material", there is disclosed an electromagnetic wave shielding resin material obtained by uniformly mixing metal fibers with a thermoplastic resin and molding. Further, in JP-A-56-159248, "A thermoplastic resin composition", a thermoplastic resin composition in which a metal powder is mixed with a polytetramethylene terephthalate resin is proposed.

(Problems to be Solved by the Invention) It has been conventionally performed to mix a thermoplastic resin with a metal filler to impart functionality such as conductivity and electromagnetic wave shielding property and to increase the specific gravity, but most metal fillers are used. Has insufficient corrosion resistance and is easily oxidized. As a result, there is a problem in that the functionality of the electro-conductivity and the electromagnetic wave shielding property is deteriorated and the appearance of the surface of the molded product is deteriorated due to rust.

As a method of improving this problem, surface treatment of metal fillers with chemicals such as benzotriazole and sebacate chromate is carried out, but its rust preventive effect is not sufficient.

(Means for Solving Problems) As a result of intensive studies to improve the problems of the prior art, the present inventors have found that the surface of a thermoplastic resin composition containing a metal filler is treated with 3- (2-benzo). The present invention has been completed based on the finding that excellent corrosion resistance is exhibited when represented by thiazolylthio) propionic acid or its alkali metal salt.

That is, the first of the present invention is the general formula (Wherein R represents a hydrogen atom or an alkali metal), which is a thermoplastic resin composition surface-treated with at least one compound represented by the formula, wherein the composition contains a metal filler. Is a thermoplastic resin composition.

The second aspect of the present invention is the general formula (Wherein R represents a hydrogen atom or an alkali metal), which is a thermoplastic resin composition surface-treated with at least one compound represented by the formula, wherein the composition contains a metal filler. Is a thermoplastic resin composition.

 Hereinafter, the present invention will be described in detail.

General formula used in the present invention The compound represented by the formula (wherein R represents a hydrogen atom or an alkali metal) is 3- (2-benzothiazolylthio) propionic acid or an alkali metal salt thereof, and sodium is particularly preferable as the metal species.

The amount used when the thermoplastic resin composition is surface-treated with 3- (2-benzothiazolylthio) propionic acid or its alkali metal salt is an amount sufficient to coat the surface of the composition. There is no particular limitation. As the method of surface treatment, 3- (2-benzothiazolylthio) propionic acid or its alkali metal salt is dissolved in a solvent such as water, alcohol, glycol, or Kent, and then sprayed or applied on the thermoplastic resin composition. Then, a method of removing the solvent and a method of blending with a coating material for coloring and coating the same are mentioned, but the method is not particularly limited.

General formula used in the present invention The compound represented by the formula (wherein R represents a hydrogen atom or an alkali metal) is 2-mercaptobenzothiazole or an alkali metal salt thereof, and sodium is particularly preferable as the metal species.

The amount used when the thermoplastic resin composition is surface-treated with 2-mercaptobenzothiazole or an alkali metal salt thereof is not particularly limited as long as it is an amount sufficient to coat the surface of the composition. The surface treatment method is 2
-A method of dissolving mercarptobenzothiazole or its alkali metal salt in a solvent such as water, alcohol, glycol, Kent, and then spraying or coating it on the thermoplastic resin composition and then removing the solvent, or for coloring. Examples thereof include a method of blending with a paint and applying it, but the method is not particularly limited.

The thermoplastic resin used in the present invention is not particularly limited as long as it has melt fluidity by heating and can be injection-molded, but as a particularly preferable one for achieving the object of the present invention, polyamide, Examples include polyester, polyolefin, polystyrene, polyphenylene oxide, polycarbonate, and ABS resin.

The metal filler used in the present invention is a fiber, powder or flake of iron, copper, aluminum, zinc, tin, lead or the like, and particularly preferable examples thereof include iron, copper and aluminum. ， Aluminum-based alloys such as low carbon steel, silicon steel, cobalt steel / permalloy, chrome steel, stainless steel, manganese steel, molybdenum steel, vanadium steel, titanium steel, niobium-vanadium steel, brass, bronze, etc. preferable. Further, two or more kinds of these metal fillers can be used in combination.

The compounding amount of the metal filler in the present invention is conductivity, electromagnetic wave shielding property, a desired function such as high specific gravity, type of the metal filler, ordinarily varies depending on the shape, with respect to 100 parts by weight of the thermoplastic resin. The metal filler is 20 to 500 parts by weight, preferably 50 to 400 parts by weight. The blending of the metal filler into the thermoplastic resin may be such that the thermoplastic resin and the metal filler are uniformly kneaded and dispersed at any stage until the final injection molding process, for example, with a predetermined amount of the metal filler. Melt kneading with a thermoplastic resin using a single-screw kneader or a multi-screw kneader to produce pellets may be followed by injection molding. Alternatively, the melt kneading step may be omitted, and direct kneading injection molding may be performed. Good.

In the present invention, for the purpose of improving other properties, colorants, lubricants,
Additives such as foaming agents, flame retardants, stabilizers, and reinforcing materials such as glass fibers and carbon fibers can also be used together.

 Hereinafter, preferred embodiments of the present invention will be described.

(A) The composition according to claim 1 or 2, wherein the thermoplastic resin is polyamide, polyester, polyolefin, polystyrene, polyphenylene oxide, polycarbonate and ABS resin.

(B) The composition according to claim 1 or 2, wherein the metal filler is iron, copper, or aluminum.

(Effects of the Invention) The thermoplastic resin composition subjected to the surface treatment according to the present invention has excellent corrosion resistance and maintains a good molding appearance without rust generation for a long period of time.

(Example) Hereinafter, a more detailed description is given using an example.

Example 1 Polybutylene terephthalate resin (PBT manufactured by Kanebo Co., Ltd.)
720) 100 parts by weight and 200 parts by weight of iron powder (KIP300A, manufactured by Kawasaki Steel Co., Ltd.) that passed through a 200 mesh screen were melt-kneaded with a biaxial kneader to obtain pellets. The pellets obtained were then used to mold 8 × 150 × 2 mm plate samples under the usual injection molding conditions for polybutylene terephthalate resin.

After spraying a 3% ascent solution of 3- (2-benzothiazolylthio) propionic acid sodium salt on this plate sample, the ascent was removed by performing a heat treatment for 30 minutes in a hot air dryer at 100 ° C.

Next, a spray test with 1% saline solution was performed for 168 hours. The sample showed excellent corrosion resistance and no rust was generated.
A good appearance shape was maintained.

Example 2 All tests were performed in the same manner as in Example 1 except that 3- (2-benzothiazolylthio) propionic acid sodium salt of Example 1 was replaced with 3- (2-benzothiazolylthio) propionic acid. Was carried out.

The obtained sample showed excellent corrosion resistance equivalent to that of Example 1, did not generate rust, and maintained a good appearance shape.

Comparative Example 1 The plate sample obtained in Example 1 was subjected to a spray test of 1% saline for 168 hours without applying the surface treatment according to the present invention, but rust was generated on the entire sample surface.

Example 3 6 Nylon resin (manufactured by Kanebo Co., Ltd., MC-102) 100 parts by weight and 400 parts by weight of iron powder (KIP300A, manufactured by Kawasaki Steel Co., Ltd.) passing through a 200 mesh screen were melted in a twin-screw kneader. Kneading was performed to obtain pellets. Then, the obtained pellets were used to mold a plate sample of 80 × 150 × 2 mm under the usual injection molding conditions of 6 nylon resin.

After spraying a 3% ascent solution of 2-mercaptobenzothiazole sodium salt on this plate sample,
The ascent was removed by performing a heat treatment for 30 minutes with a hot air dryer at 100 ° C.

Next, a 168-hour spray test was performed using a 1% saline solution. The sample exhibited excellent corrosion resistance, no rust was observed, and a good appearance was maintained.

Example 4 Polybutylene terephthalate resin (PBT manufactured by Kanebo Co., Ltd.)
720) 100 parts by weight and 150 parts by weight of iron fiber having a fiber diameter of 30 μm and a fiber length of 2 mm (S15C, manufactured by Kobe Cast Iron Co., Ltd.) were melt-kneaded with a biaxial kneader to obtain pellets. The pellets obtained were then used to mold 80 × 10 × 2 mm plate samples under the usual injection molding conditions for polybutylene terephthalate resin.

The plate sample was sprayed with a 3% ascent solution of 2-mercaptobenzothiazole and then heat-treated for 30 minutes at 70 ° C. in a hot air dryer to remove ascent.

Next, a corrosion resistance test was performed for 1,000 hours in an atmosphere of 70 ° C and 90% relative humidity, and the sample showed excellent corrosion resistance.
Maintained a good appearance without rust.

Comparative Example 2 For the plate samples obtained in Examples 3 and 4,
Without subjecting the sample to the surface treatment according to the present invention, a spray test of 1% saline solution for 168 hours and a corrosion resistance test for 1,000 hours in an atmosphere of 70 ° C. and 90% relative humidity were conducted on each sample. Rust generation was observed on the whole.

As is clear from Examples and Comparative Examples, the surface-treated thermoplastic resin composition of the present invention exhibits excellent corrosion resistance and is suitable as a molding material for electronic / electrical device parts and the like.

Claims (2)

(57) [Claims] 1. A general formula (Wherein R represents a hydrogen atom or an alkali metal), which is a thermoplastic resin composition surface-treated with at least one compound represented by the formula, wherein the composition contains a metal filler. A thermoplastic resin composition. 2. General formula (Wherein R represents a hydrogen atom or an alkali metal), which is a thermoplastic resin composition surface-treated with at least one compound represented by the formula, wherein the composition contains a metal filler. Thermoplastic resin composition.