JPH02239604A - Flexible magnetic material - Google Patents

Abstract

PURPOSE:To improve the long-term durability of aging resistance or flexibility by combining polyvinyl chloride, a trimellitic acid group heat-resistant plasticizer and ferrite powder. CONSTITUTION:1300 pt. ferrite powder having mean grain size of 1mum is added and kneaded homogeneously to the mixed liquid of 100 pt. (pts.wt.) polyvinyl chloride, 150 pt. trimellitic acid trioctyl and a 7 pt. lead stearate group stabilizer, thus obtaining a flexible magnetic material. The flexible magnetic material can be prepared in the proper type of paste, a pellet, etc., and can be applied to a body to be treated through an application system such as a spray system, a coating system, etc. The material can also be machined in the arbitrary type of a sheet, a bar body, etc., through a proper molding means such as an extrusion molding system. Accordingly, excellent flexibility is maintained stably for a prolonged term in outdoor use, and the reliability of a communication system using such a cable is improved.

Description

[Detailed Description of the Invention] Industrial Application Field The present invention uses a trimellitic acid-based heat-resistant plasticizer to improve durability, and is suitable for electromagnetic shielding materials, flexible magnetic core materials, etc. This invention relates to flexible magnetic materials based on polyvinyl chloride and ferrite.

Conventional technology and problems: Ferrite powder is dispersed in polyvinyl chloride,
Magnetic materials made flexible with plasticizers can be used as electromagnetic shielding materials,
It is used as a flexible magnetic core material for medium wave induction coaxial cables for roadside roads.

Roadside roadside medium-wave induction coaxial cables are installed along roads, etc., and are used in systems that emit radio waves and transmit information to drivers via receivers such as car radios. Its general structure is that an inner conductor layer, a resin insulating layer, an outer conductor layer, a pressure tape layer, and a resin sheath layer are sequentially provided on the outside of a flexible magnetic core, and the resin sheath layer is attached to the main body. The messenger wires are integrally arranged in parallel and reinforced through the wires.

Conventionally, as the aforementioned polyvinyl chloride ferrite-based flexible magnetic materials, those using phthalic acid compounds such as cyoctylphthalate as plasticizers have been known. However, it has problems in that it ages quickly, tends to lose flexibility, and is poor in durability.

Means for Solving the Problems As a result of extensive research by the present inventors in order to develop a polyvinyl chloride ferrite-based flexible magnetic material that maintains its flexibility for a long period of time and has excellent durability, The inventors have discovered that the objective can be achieved by using a trimellitic acid-based heat-resistant plasticizer, and have completed the present invention.

That is, the present invention provides a flexible magnetic material containing polyvinyl chloride, a plasticizer, and ferrite powder as components, characterized in that the plasticizer used is a trimellitic acid-based heat-resistant plasticizer. The present invention provides a magnetic material.

By combining polyvinyl chloride, trimellitic acid-based heat-resistant plasticizer, and ferrite powder, it maintains initial properties comparable to conventional products, while dramatically improving aging resistance and long-term flexibility. to improve.

Examples of Constituent Elements of the Invention The flexible magnetic material of the present invention contains a trimellitic acid-based heat-resistant plasticizer, polyvinyl chloride, and ferrite powder.

Examples of usable trimellitic acid-based heat-resistant plasticizers include trioctyl trimellitate, isononyl trimellitate, isodecyl trimellitate, and the like.

Known materials may be used for polyvinyl chloride as a binder and ferrite powder as a magnetizing material. The particle size of the ferrite powder is 100 μl or less, especially 20 or less,
In particular, 0.1 to 5 uI is suitable.

The flexible magnetic material can be prepared by using one or two of the above-mentioned components.
This can be carried out by using more than one species and mixing them with an appropriate kneader or the like. In this case, it is more suitable to prepare a homogeneous mixture by mixing polyvinyl chloride and a trimellitic acid-based heat-resistant plasticizer in advance, and then mixing the ferrite powder into the mixture. Note that additives such as stabilizers may be added to the mixture.

The mixing ratio of each component is 100 parts by weight of polyvinyl chloride, 50 to 300 parts by weight of trimellitic acid-based heat-resistant plasticizer, especially 100 to 200 parts by weight, and 800 to 800 parts by weight of ferrite powder.
1800 parts by weight, especially 1000 to 1600 parts by weight is suitable. The mixing ratio of trimellitic acid-based heat-resistant plasticizer is 5
If it is less than 0 parts by weight, the effect of imparting flexibility is poor;
If the amount exceeds 1 part by weight, the resulting magnetic material will have poor strength. On the other hand, if the mixing ratio of ferrite powder is less than 800 parts by weight, the resulting magnetic material will have poor magnetic properties.
If the amount exceeds 0 parts by weight, the resulting magnetic material will have poor strength. The mixing ratio of additives used as necessary is as follows:
It is appropriate that the amount is 50 parts by weight or less, particularly 30 parts by weight or less, per 100 parts by weight of polyvinyl chloride.

The flexible magnetic material of the present invention can be prepared in an appropriate form such as a paste or pellet. Therefore, it can be applied to the object to be treated using a coating method such as a spray method or a coating method. Further, it can be processed into any desired form such as a sheet or a body by an appropriate molding method such as an extrusion molding method.

The flexible magnetic material of the present invention can be preferably used as an electromagnetic shielding material or electromagnetic shielding material in electric wires, electric/electronic devices, etc., a flexible magnetic core material, and the like. In particular, since it has excellent aging resistance, it can be advantageously used in devices used outdoors.

Effects of the Invention According to the present invention, since a trimellitic acid-based heat-resistant plasticizer is used, a polyvinyl chloride ferrite-based flexible magnetic material with excellent aging resistance and long-lasting flexibility is obtained. be able to.

Therefore, when applied to a flexible magnetic core material of a medium wave induction coaxial cable for roadside roads, for example, it maintains stable and good flexibility for a long period of time during outdoor use, and information transmission using such a cable is possible. Improve system reliability.

Examples Example 1 1300 parts of ferrite powder with an average particle size of 1 μI was added to a mixed solution of 100 parts by weight of polyvinyl chloride (parts by weight, same hereinafter), 50 parts of trioctyl trimellitate, and 7 parts of a lead stearate stabilizer. The mixture was homogeneously kneaded to obtain a flexible magnetic material.

Example 2 A flexible magnetic material was obtained according to Example 1, except that the amount of trioctyl trimellitate used was 170 parts.

Comparative Example A flexible magnetic material was obtained according to Example 1, except that 130 parts of dioctyl phthalate was used instead of trioctyl trimellitate.

Using the flexible magnetic materials obtained in the evaluation test examples and comparative examples, a thickness of 2 m was obtained.
A sheet was formed and its tensile strength, elongation, and embrittlement temperature were examined. In addition, we conducted a heat aging acceleration test at 100°C for 5 days.
The tensile strength and elongation of the test specimens after the test were examined.

The results are shown in Table 1.

Table 1 Examples 3 to 5 Flexible magnetic materials were obtained according to Example 1 by varying the mixing ratio of trioctyl trimellitate (TOTM) and ferrite powder to 100 parts of polyvinyl chloride, and the same as above. An evaluation test was conducted. The results are shown in Table 2.

From Table 2 and Table 1, it can be seen that the flexible magnetic materials of the examples showed a small degree of deterioration after the accelerated heat aging test, and had almost the same physical property values as the conventional materials at the initial stage.

Patent applicant: Mitsubishi Cable Industries, Ltd.

Claims (1)

[Claims] 1. A flexible magnetic material comprising polyvinyl chloride, a plasticizer, and ferrite powder as components and having flexibility, characterized in that the plasticizer used is a trimellitic acid-based heat-resistant plasticizer.