JPS5841643B2 - ferrite composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a ferrite composition that has a high degree of magnetism, good injection moldability, and excellent heat resistance.

Among magnetic materials, the appearance of ferrite has led to the phenomenal development of magnetic materials.

The spread of today's portable radios, televisions, etc. is largely due to the effects of ferrite.

Conventionally, ferrite has been molded by a sintering method and used for the above-mentioned purposes.

However, the sintering method has problems such as difficulty in molding complex products, which limits the scope of its application, and complicated operations and low productivity.Therefore, the emergence of a new molding method is desired. was.

In order to solve this problem, a method of blending ferrite into a thermoplastic resin and molding it into a desired shape by injection molding or other methods has been considered.

As thermoplastic resins, polypropylene and polyamide are frequently used today.

Among these, ferrite/polyamide compositions are particularly used because polyamides have excellent heat resistance and flame retardancy.

However, the moldability itself of this composition is not fully satisfactory, and furthermore, in order to improve the molded product, it is necessary to reduce the ferrite concentration.

The present inventors have continued their research to obtain a ferrite composition that has a high degree of magnetism, good injection moldability, and excellent heat resistance. The inventors have discovered that the above object can be achieved by using a copolymer, and have completed the present invention.

The first invention of the present invention is that hexamethylene adipamide 5
The second invention is a ferrite composition consisting of a 10-50 weight cup of polyamide copolymer made of 0-90 weight φ and 10-50 weight proportion of ε-cabrolactamide, and a 50-90 weight cup of ferrite. Methyleneadipamide 50-90% by weight and ε-cabrolactamide 10-50%
A ferrite composition consisting of a polyamide copolymer of 10 to 50 weight φ and a ferrite of 50 to 90 weight φ selected from ethylene bis stearylamide, ethylene bis stearylamide derivatives, and stearate. Alternatively, it is a ferrite composition containing two or more types.

The ferrite referred to in the present invention is ferrite and M”0・F
It is expressed in the form e2O3.

Here, Mll is Mn, Fe, Co, Ni, Cu, Zn
, Mg, and Cd.

In particular, a solid solution of Zn ferrite is put into practical use as a magnetic material for high frequency waves.

Mn-Zn, Ni-Zn. Mg-Mn ferrite is a typical example.

Other types include barium ferrite, ferrotox planer, and others with magnetoblumbite-type structures, as well as rare earth metal salts such as iron garnet.

The grain size of the ferrite is desirably 0.5 to 10μ, preferably 1 to 5μ.

For magnetic performance, small particle size is desirable, but
The above range is preferable in relation to the pulverization process.

The ferrite composition in the composition of the present invention is 50 to 90
It is a weight factor, and is preferably 70 to 90 weight φ.

If the weight is less than 50%, the magnetic performance will not be sufficient, and if the weight exceeds 90%, the moldability will deteriorate.

The polyamide copolymer of the present invention contains 50 to 90% by weight of hexamethyleneadipamide and 10 to 5% by weight of ε-cabrolactamide.
0 weight, preferably hexamethylene adipamide 60-8
It is a polyamide copolymer consisting of 0% by weight and 20 to 40% by weight of ε-cabrolactamide.

If hexamethylene adipamide is less than 50% by weight, the heat resistance of the ferrite composition, which is a characteristic of using polyamide, will be poor, while if it exceeds 90% by weight, it will be difficult to blend ferrite at a high concentration, and The surface gloss of the ferrite composition molded product is poor.

The polyamide copolymer according to the present invention is a copolymer containing hexamethylene adipamide as a main component and ε-cabrolactamide as a subcomponent, and is compared to a copolymer containing the former as a subcomponent and the latter as a main component. Ferrite compositions have much better heat resistance.

Incidentally, in place of the polyamide copolymer referred to in the present invention, a copolymer of a hexamethylene sepaamide component and an ε-caprolactamide component can of course be used, but this is not preferred for industrial purposes.

A composition in which a ferrite composition consisting of a ferrite and a polyamide copolymer contains one or more selected from ethylene bis stearylamide, an ethylene bis stearyl amide derivative, and a stearate is based on a synergistic effect. The fluidity of the acid form is further improved, the frictional resistance with the high concentration ferrite mixer cylinder is reduced, and the kneading power is significantly reduced.

Especially when using ethylene bisstearylamide,
The effect is remarkable.

For the purpose of imparting flame retardancy, a halogen-based flame retardant represented by Dechlorane Plus, a nitrogen-based flame retardant represented by melamine, etc. can be added.

Additionally, additives for the purpose of preventing thermal deterioration, ultraviolet deterioration, etc. may be added to these.

The composition of the present invention is produced by melt-mixing the ferrite and polyamide copolymers, usually using a screw-screw or twin-screw extruder.

Specifically, there is a method in which granules of ferrite powder and polyamide copolymer are premixed, and the mixture is charged into an extruder hopper and heated and melted and granulated. A common method is to melt the material by heating and then add ferrite powder thereto through a hole provided in the middle of the extruder cylinder and mix.

The composition of the present invention contains a high concentration of ferrite and has excellent heat resistance and moldability.

The surface gloss of molded articles made from this composition is also extremely good.

Furthermore, when a fluidity improver is added, it acts more effectively than when added to other compositions, and the kneading power can be significantly reduced.

Next, the present invention will be explained according to examples.

Examples 1 to 4 and Comparative Example 1 Barium ferrite (Murata Manufacturing product + 601 average particle size 3.1μ) and polyamide copolymer (copolymer consisting of hexamethylene adipamide 65% by weight and cabrolactamide 35% by weight φ) The granular material (3 mm φ4 mm) is first
Premix in the proportions shown in Table 1, and use a single screw extruder (70mmφL).
/D=30) at a temperature of 260° C. to obtain a composition.

The results are shown in Table 1.

From Table 1, it can be seen that Comparative Example 1, in which ferrite was used in an amount outside the range of the present invention, had poor extrusion granulation properties.

Examples 5 to 8 and Comparative Examples 2 to 4 160 kg of barium ferrite and polyamide grain body (31rLrILφ4imL) 401y used in Example 1
Pre-mix and use a single screw extruder (70 mm φL/D = 30
) at the temperature shown in Table 2 to obtain a composition.

The composition of the polyamide is shown in Table 2.

From Table 2, Comparative Examples 2 and 3 using polyamide copolymers containing less cabrolactamide than the amount specified in the present invention have poor granulation formability, low SFD, and large amounts of cabrolactamide.

It can be seen that in Comparative Example 4, the injection molded product has a low heat distortion temperature.

Examples 9 to 12 160 kg of barium ferrite used in Example 1, polyamide copolymer (copolymer consisting of 80 weight φ of hexamethylene adipamide and 20 weight φ of cabrolactamide)
40 kg of granules (3 mm φ 4 mm L) and ethylene bisstearylamide were premixed, and a composition was obtained at a temperature of 260° C. using a single screw extruder (70 mm φ L/D = 30).

The results are shown in Table 3.

Examples 13-14 and Comparative Examples 5-1゜ Barium ferrite used in Example 1 4 okg and 4th
50 kg of various thermoplastic resin pellets shown in the table)
Each resin was extruded and pelletized using a single-screw extruder at an appropriate temperature, and then molded using an injection molding machine.

The extrudability and moldability were observed, and the heat distortion temperature and tensile strength at break of the injection δ-shaped product were measured.

The results are shown in Table 4. Table 4 shows that the ferrite composition of the present invention is superior to ferrite compositions using resins other than the resin used in the present invention.

Claims (1)

[Claims] 1 Hexamethyleneadipamide 50-90 weight ratio and ε
- polyamide copolymer consisting of cabrolactamide 10-50 weight φ, and ferrite 50-50 weight
Ferrite composition 2 consisting of hexamethylene adipamide 50 to 90 weight φ and ε-
polyamide copolymer consisting of cabrolactamide 10-50 weight percent, and ferrite 50-9 weight percent
1. A ferrite composition comprising a ferrite composition comprising 0 weight rice and one or more selected from ethylene bis stearylamide, an ethylene bis stearyl amide derivative and a stearate.