JPH02191655A - Resin composition - Google Patents

Abstract

PURPOSE:To obtain a resin composition having good balance of tensile characteristics, low-temperature flexibility and heat resistant aging properties without impairing electromagnetic wave absorbing characteristics even when ferrite is contained at large quantities and capable of readily carrying out thin wall extrusion molding by blending a fluororubber with ferrite, waxs, etc. CONSTITUTION:The aimed composition obtained by blending (A) 100 pts.wt. fluororubber with (B) 200-600 pts.wt., preferably 300-400 pts.wt. ferrite (e.g. Mn-2n based ferrite) having 1-10mum granule size, (C) 0.5-10 pts.wt. preferably 2-5 pts.wt. waxs (e.g. carnauba wax), (D) 0.5-10 pts.wt., preferably 2-5 pts.wt. liquid fluorosilicone having >=300cp viscosity and (E) 1-10 pts.wt. crosslinking auxiliary.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a resin composition, and more particularly to a resin composition containing fluororubber and ferrite.

[Conventional technology]

In order to improve the electromagnetic wave absorption characteristics of fluororubber compositions, ferrite has conventionally been blended into the compositions. Among these, Mn--Zn-based ferrites, Mn, and -NI-based ferrites are actually used, and compositions containing these ferrites are often used in microwave ovens used in very high frequency ranges, for example, on the order of GHz.

However, in order to sufficiently satisfy the electromagnetic wave absorption characteristics by incorporating ferrite, it is necessary to incorporate a large amount of ferrite, and it is usually necessary to increase the weight of the composition by about 60 to 80% by weight. Blending such a large amount leads to the difficulty that the composition cannot satisfy the tensile properties, low-temperature flexibility, and heat aging resistance in a well-balanced manner on average.This difficulty is particularly important when the composition is used for electric wires. This is especially noticeable when the conductor is coated with a thin film, for example 0.1n! This is a fatal drawback in that it is extremely difficult to form the film as thin as 100 degrees.

[Invention tries to solve! I! The problem to be solved by the present invention is to solve the above-mentioned conventional difficulties.More specifically, even if a large amount of ferrite is contained, the tensile properties, low-temperature flexibility, and heat aging resistance are all good. The objective is to develop a resin composition whose main component is fluororubber, which can be produced in a well-balanced manner and can be extruded into thin walls.

[Means to solve lIH]

This problem is solved by incorporating waxes, more preferably waxes and liquid fluorosilicone, into a resin composition containing fluororubber and ferrite.

[Function and structure of the invention]

By blending at least one type of wax into the fluororubber composition, even if the composition contains a large amount of ferrite, the tensile properties and low temperature properties of the composition can be improved without impairing the 1i magnetic wave absorption properties of the ferrite. Flexibility and heat aging resistance are well-balanced and it becomes possible to easily perform thin-wall extrusion molding. Furthermore, when fluorosilicone is blended with waxes, heat aging resistance and TIF
The viscoelasticity of the composition can be lowered without impairing the f-wave absorption properties and other properties, and the moldability is further improved.

The wax used in the present invention acts as a processing aid, and various types can be used, but carnauba wax is particularly preferred.Carnauba wax is made from a tree called carnauba. The amount of wax to be mixed is 0.5 to 10 parts by weight, preferably 2 to 5 parts by weight, based on 100 parts by weight of fluororubber. When the amount of ferrite is less than 0, st, it is difficult to achieve the above-mentioned effects, and especially when the amount of ferrite is large, the effect is insufficient. In addition, if more than 10 parts by weight is added, the viscosity of the composition becomes extremely low, which not only impairs the appearance and especially the smoothness of the molded product, but also tends to cause deformation due to force and decrease tensile properties. .

The liquid fluorosilicon used as necessary in the present invention may contain a third element other than F or Si in its molecule, and has a viscosity (at 25°C) of 300e, p or more. , preferably the same viscosity is 300-10000
c, p, etc., particularly preferably 300 to 1000
It is around c and p. A specific example is rF of Dow Corning Co., Ltd.
S-1265FluidJ is an example, especially 300e
, p, , 1000c, p, , 10000c, p (both at 25°C) can be preferably used. Liquid fluorosilicone! The total amount is 0.5 to 10 parts by weight, preferably 2 to Sat parts, based on 100 parts by weight of fluororubber, and if it does not reach 0.5 parts by weight, the effect of its addition will not be fully exhibited. , or more than 10 parts by weight, the lubricity becomes strong, resulting in poor moldability and moldability, which is undesirable.

As the fluororubber used in the present invention, any of those conventionally used in this type of field can be used, and typical examples include fluoroethylene-fluoropropylene, fluoroacrylate, Fluorosilicon-based, perfluoroether-based, and fluorophosphazene-based polymers are preferred, particularly fluoroethylene-fluoropropylene-based polymers, tetrafluoroethylene-hexafluoropropylene copolymers, or these copolymers. A terpolymer copolymerized with a third component is preferable, and the above-mentioned terpolymer is particularly preferable because its heat resistance is significantly improved when cross-linked by irradiation with an electron beam. Examples include those using vinylidene chloride, and more specifically, those using DuPont (Ou Pont).
t) company's "Viton (VHori) G L T J,
"Aftefukus" manufactured by Asahi Glass Co., Ltd. is an example.

Ferrites that have traditionally been used can be used, typically a mixture of iron oxide and one or more gold i-oxides such as nickel oxide and zinc oxide, and heated at high temperatures, for example around 1200°C. Ferrite is often expressed by the element name of the metal oxide that coexists with iron oxide. Ferrite is a typical example. The particle size of ferrite is usually 1
If the particle size is too large, which is about 10 μm, preferably about 1 to 4 μm, the appearance of the molded product tends to be impaired and the tensile properties may deteriorate.

It is desirable that ferrite has high purity, especially C1,
N Jl s S IO@ and S Oa groups are preferred.

The blending amount of ferrite is 200 to 600 parts by weight, preferably 300 to 400 parts by weight, per 100 parts by weight of fluororubber.
Parts by weight. If the amount is less than 200 parts by weight, the electromagnetic wave absorption properties will be insufficient, while if it is more than 600 parts by weight, it will be difficult to sufficiently improve extrusion moldability even if a large amount of wax is added.

In the composition of the present invention, carbonyl iron,
Magnetic wave absorption property improvers such as barium titanate, carbon black, iron oxide, metal fibers, etc. can be added. In addition, metal oxides such as antimony oxide, titanium oxide, zinc oxide, yttrium oxide, aluminum oxide, silicon oxide, and zirconium oxide can be used as heat resistance improvers, and the blending amount is the ai of the gold yA oxide used.
Although it depends on m, it is usually 0.5 per 100 parts by weight of fluororubber.
~10 parts by weight. Furthermore, various antioxidants and copper damage inhibitors such as hindered phenol type, amine type, quinone type, sulfur type, and mercaptobenzimidazole type can also be used.

The composition of the present invention can also be crosslinked to improve its heat resistance and shapeability at high temperatures. The crosslinking means in this case is not particularly limited, and examples include means such as irradiation crosslinking with radiation such as electron beams, chemical crosslinking with a crosslinking agent such as peroxide, and the like. When crosslinking is carried out by irradiation with an electron beam or the like, it is preferable to use a crosslinking auxiliary agent in order to crosslink more efficiently. Examples include polyfunctional compounds such as phthalates.

These auxiliary agents are 0.5 to 100 parts by weight of fluororubber.
The amount used is about 10 parts by weight, preferably about 1 to 1 part by weight.

〔Example〕

Examples and comparative examples are shown below to make the features of the present invention more clear.

Example 1-% A composition was prepared by kneading predetermined amounts (all parts by weight) of the predetermined components shown in Table 1 by the method shown below.

First, roll the fluororubber using two rolls set at 50℃.
Ferrite was added and kneaded while the mixture was being heated. During this kneading, carnauba wax (and liquid fluorosilicone) was gradually added, and finally a crosslinking aid was added once to produce a composition.

Comparative Examples 1 to 2 Compositions were produced by using predetermined amounts (all parts by weight) of the predetermined components shown in Table 1 and treating them in the same manner as in the examples.

Each of the above compositions was formed into a sheet approximately 2 fl thick, and 10 g of pellets were cut out from this sheet and placed in a melt indexer.
The melt index (hereinafter referred to as M!) was measured with #
The Mr is 5636 kg at 235°C, i90°C
The measurements were taken with a load of 2160 kg applied to each. The results are shown in Table 1.

In addition, in order to measure extrusion processability, each composition was
0.813mφ at 200℃ using a lab blast mill of
The smoothness of the external appearance of the obtained extruded product was measured with the naked eye, and the smoothness was divided into equal lines according to the following criteria. The results are also shown in Table 1.

○... Good △... Slightly poor smoothness ×... Poor smoothness Using each composition obtained in Examples 1 to 7, these were
．． An annealed copper wire of 813 mφ was extrusion coated to a thickness of 0.100, and then crosslinked with a 10 Mrad electron beam to produce an insulating wire having a smooth surface coating layer.

[Margin below]

Claims (3)

[Claims] (1) A resin composition characterized by containing fluororubber, ferrite, and waxes. (2) The resin composition according to claim 1, which uses carnauba wax as the wax and further contains liquid fluorosilicone. (3) Ferai and 20% per 100 parts by weight of fluororubber
0 to 600 parts by weight, waxes 0: 5 to 10 parts by weight, liquid fluorosilicone 0.5 to 10 parts by weight, and crosslinking aid 1
3. The resin composition according to claim 1, comprising 10 parts by weight.