JPS5835217B2 - The horned horned elephant - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Soft magnetic ferrite has rapidly developed after the war and has become an indispensable material, particularly in the field of electronic technology.

Its characteristics are 1) high magnetic permeability, il) high electrical resistivity, and 111) low cost.

However, these ferrites are currently molded by sintering powder, so i) the yield and dimensional stability during molding are poor, 11) it is difficult to obtain molded products with complex shapes, and in some cases 111) Since the surface oxidation during sintering is significant, it has disadvantages such as being unsuitable for small-sized products.

The present inventors have discovered that by blending soft magnetic ferrite with liquid rubber, it is possible to obtain a soft magnetic ferrite composition that can be molded into complex shapes with good dimensional stability under mild conditions without sintering. However, the present invention was achieved as a result of further detailed study of the composition, and according to the present invention, when mixing soft magnetic ferrite with liquid rubber, carboxylic acid ester compounds, amine compounds, or these compounds are mixed. A mixture of 0.1 to 5 for ferrite
By coexisting in a weight percentage, the amount of ferrite filled is further increased, and moldability and processability are improved.

If a carboxylic acid ester compound, amine compound, or a mixture thereof is not present during kneading of liquid rubber and ferrite, if ferrite is blended in an amount exceeding 10 times the weight of liquid rubber, it cannot be molded by normal molding means.

On the other hand, if a carboxylic acid ester compound, amine compound, or a mixture thereof is present, 1
Up to 4 times the weight of ferrite can be blended.

Furthermore, when a carboxylic acid ester compound, an amine compound, or a mixture thereof is present, the viscosity of the liquid rubber-ferrite mixture is reduced compared to a case where the compound is not present, thereby significantly improving moldability.

For example, when kneading 9 times the weight of manganese/zinc ferrite with liquid polybutadiene (average molecular weight 4000), the rotational torque of the plastograph is 240 mm when the carboxylic acid ester compound, amine compound, or mixture thereof is not present. 9/m2, whereas the presence of 1.0 percent methyl oleate to ferrite reduces it to 153/2/d.

Therefore, according to the method of the present invention, even a composition filled with a large amount of ferrite can be molded using an ordinary extrusion molding machine or injection molding machine, and the economical benefits in terms of processing steps are significant.

In the present invention, liquid rubbers include liquid polyphtadiene, liquid polyisoprene, liquid polyisobutylene, copolymer liquid rubbers thereof, and derivatives in which hydroxyl groups, carboxyl groups, maleic anhydride groups, incyanato groups, etc. are introduced into these polymers. It can be widely used.

Depending on the viscosity of the liquid rubber used, the composition of the present invention has
Its formability is affected.

For example, in rubbers with excessively low viscosity, in other words with low molecular weight, the chain length is too short for the liquid rubber to serve as a binder or matrix for the ferrite.

On the other hand, if the molecular weight is excessively high, the viscosity of the composition becomes too high, making it difficult to mold it using normal molding means.

Therefore, it goes without saying that the liquid rubber used must have an appropriate molecular weight based on preliminary experiments, depending on the type of ferrite or the molding method used.

For example, in the case of liquid polybutadiene rubber, those having an average molecular weight in the range of 1,000 to 10,000 are preferably used.

The higher the mixing ratio of ferrite to liquid rubber, the more desirable it is from the viewpoint of magnetic properties.

If the mixing ratio is less than 1:1 by weight, a practical magnetic core material cannot be obtained.

On the other hand, if the mixing ratio exceeds 14 times by weight, the viscosity of the composition becomes too high, the flow of the composition during molding becomes poor, and moldability and processability deteriorate.

Polar organic compounds that can be used in the present invention include carboxylic acid ester compounds, amine compounds, or mixtures thereof.

Examples of carboxylic acid ester compounds include methyl laurate,
As an amine compound such as methyl oleate,
n-butylamine, hexamethylenediamine, laurylamine, etc. can be used.

All of these compounds may be added in the required amount during kneading, but if a part or all of the required amount is applied to the ferrite in advance by a well-known gas phase method or liquid phase method as a surface treatment method, the addition effect can be improved. is even more remarkable.

The amount of polar organic compound added is 0.1 to ferrite.
It should be within the range of ~5 weight percent; if the amount added is less than o,i percent, no effect will be observed, while if it exceeds 5 weight percent, it will lead to a decrease in the mechanical strength of the composition. Furthermore, a so-called bleed phenomenon occurs in which the surface of the composition becomes sticky.

Mixing of ferrite powder and liquid polybutadiene can be carried out by a conventional kneading method.

Next, the kneaded composition is processed using an injection molding machine, an extrusion molding machine,
It can be molded into any shape using a compression molding machine or a calendar molding machine.

The composition according to the present invention can be easily cured by adding a crosslinking agent or a vulcanizing agent during kneading.

The cured composition thus obtained has a rigidity of 1010 dyne/cri even at 300°C,
It can withstand continuous use at 120°C, which is normally required when used in electrical parts.

The composition obtained according to the present invention can be widely used in fields where sintered ferrite has conventionally been used.

Specific examples include horizontal output flyback transformers for televisions, cores for deflection coils, and antenna coils for radios.

The present invention will be explained below with reference to examples, but these examples are not intended to limit the scope of the present invention.

Examples 1 to 8 1 hour of manganese/zinc ferrite and 20.9 hours of methyl oleate or t')-n-butylamine were heated at 180° C. for 1 hour with stirring.

The manganese/zinc ferrite treated with methyl oleate or the manganese/zinc ferrite treated with tri-n-butylamine thus obtained was subjected to the following experiments.

Liquid polybutadiene with an average molecular weight of 4000 (manufactured by Nippon Soda Co., Ltd., N15SOPB-4000), liquid polybutadiene with an average molecular weight of 3000 into which a terminal hydroxyl group has been introduced (manufactured by Nippon Soda Co., Ltd., N15SOPBG-3000), and manganese and zinc treated with methyl oleate in a predetermined weight times. A cylindrical chip with a diameter of 2 mm and a length of 5 mm is created by kneading 2% dicumyl peroxide with ferrite and polybutadiene in a kneader at room temperature, then extruding it into a rod shape with an extruder and cutting it. did.

The chips were injection molded under the conditions of a cylinder temperature of 50°C, a mold temperature of 20°C, and an injection pressure of 500 K9/crit.
A plate-shaped test piece was obtained, measuring 20 mm in width, 50 mm in width, and 3 mm in thickness.

The moldability was good.

By heating the test piece at 150°C for 3 hours, A cured composition was obtained.

Table 1 shows the magnetic properties of the obtained cured composition.

Example 9 The following mixture was kneaded at room temperature using a kneader.

12g liquid polybutadiene with average molecular weight 6200 (manufactured by Nippon Zeon Co., Ltd., polyoil 160) Tri-butylamine treated manganese/zinc ferrite 168g sulfur
Yellow 0.96.9 Active zinc white 0.60.9 Stearic acid 0.12g Vulcanization accelerator (Mexela DM) 0.1i Vulcanization accelerator (Mexela H) 0.04.9 Anti-aging agent (Tsuklak NS# 6) 0.11 Then, the mixture was molded in exactly the same manner as in Examples 1 to 8 to obtain a cured composition.

The Bm of the obtained cured product was 4111G.

Claims (1)

[Claims] 1. A composition for magnetic core material is produced by blending soft magnetic ferrite powder, which is a solid solution with ferrite represented by ZZnO-Fe203 (Mn, Fe, Ni, Cu, or Mg), into liquid rubber. When kneading liquid rubber and ferrite, a carboxylic acid ester compound, an amine compound, or a mixture thereof is added to the ferrite at a ratio of 0.1 to
A method for producing a composition for a magnetic core material having excellent moldability and processability, characterized by increasing the filling amount of ferrite by coexisting with the ferrite in an amount of 5% by weight.