JPS59176346A - Production of resin magnet molding material - Google Patents

Abstract

PURPOSE:To obtain a resin magnet molding material which has good moldability, wherein ferrite can be filled at a high concn. and highly orientated, by kneading a ferromagnetic substance with a polyamide resin contg. a polyamide oligomer. CONSTITUTION:A ferromagnetic substance is kneaded with a polyamide resin contg. a polyamide oligomer as a matrix. When the polyamide oligomer is mixed with the polyamide resin, the rotational movement of the ferromagnetic substance is facilitated during injection molding in a magnetic field by the action of said oligomer so that the orientation ratio is increased. Further, the melt viscosity of the molding material is lowered, whereby the injection molding can be easily conducted. Even when the polyamide resin is in any form of pellet and powder, similar results can be obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a resin magnet molding material that yields a resin magnet with high magnetic properties.

Conventionally, as a resin magnet molding material for injection molding, a mixed material made by mixing and kneading ferrite (M (14Feto+, M: Sr or Ba) and synthetic resins such as polyamide resin, polypropylene, vinyl chloride resin, etc.) has been used. It is commonly used because it uses polyamide resin as a matrix and has excellent heat resistance and moldability.

In order to improve the magnetic properties of a molded resin magnet, it is necessary to fill it with ferrite at a high concentration and to make the ferrite highly oriented.

However, when filled with ferrite at a high concentration, the melt viscosity of the molding material increases, causing problems such as injection molding being impossible and ferrite not being sufficiently oriented during magnetic field molding, making it impossible to obtain resin magnets with high magnetic properties.

The present invention provides a resin magnet molding material with good moldability that can be filled with ferrite at a high concentration and highly oriented. As a result of intensive research in order to provide a polyamide-based resin, polyamide was developed. That is, due to the action of the polyamide oligomer, when injection molding is carried out in a magnetic field, the ferromagnetic powder can easily move in the same direction, increasing the orientation rate. In addition, the melt viscosity of the molding material is reduced, making injection molding easier. Similar results can be obtained whether the polyamide resin used is in the form of pellets or powder.

Next, the present invention will be explained in detail with reference to Examples.

Example 1 A total of 8 parts by weight of 6-nylon having a number average molecular weight of 11,000 (hereinafter simply referred to as "parts"), 3 parts of 6-nylon oligomer having a number average molecular weight of F5000 or less, and 89 parts of strontium ferrite were mixed using a super mixer l trowel. This was mixed and kneaded in a twin-screw extruder kept at a temperature higher than the melting point of nylon 6 to obtain a pellet-shaped molding material.The resulting molding material was injection molded in a magnetic field to produce specimens for measuring magnetic properties. (2og+x
]OH) was obtained. One similar specimen for measuring mechanical strength (a
tX26WX50L) was obtained. The results of measuring the magnetic properties 1 mechanical strength of the obtained specimens are shown in Table 1 along with the distribution ratio and the melt viscosity of the molding material. [A molding material was obtained in the same manner as in Example 1 except that one part of 6 nylon oligomer having a molecular weight of 5,000 or less was used, and the evaluation results are shown in Table 1.

Comparative Example A molding material was obtained by straining in the same manner as in Example 1, except that only 211 parts of 6S,0 with a number average molecular weight of 11,000 was used, and 6Nylon oligomer was not used.
Shown in the table.

As is clear from Table 1, the molding material according to the present invention:
Its industrial value is that injection molding is easy due to its extremely low viscosity, and the ferromagnetic powder is easily oriented in a magnetic field, increasing the orientation rate, resulting in resin magnet molded products with high magnetic properties. is extremely large.

patent applicant

Claims (1)

[Claims] A method for producing a resin magnet molding material, which comprises mixing and kneading one ferromagnetic powder using a polyamide resin containing a polyamide oligomer as a matrix.