JP2001085212A - Composite magnetic body and electromagnetic interference suppressor provided therewith - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a composite magnetic body which is improved in flame retardant properties and furthermore shortened in a kindling time after self- extinguishment, by a method wherein a flame retardant material is completely or partially formed of hydroxide or/and inorganic hydrate. SOLUTION: Soft magnetic powder 3 and a titanate coupling agent are introduced into an agitator and uniformly mixed so as to enable soft magnetic powder 3 to undergo a coupling treatment. Then, soft magnetic powder subjected to a coupling treatment, chlorinated polyethylene 2, magnesium hydroxide 4, bromine polymer flame retardant material, and antimony trioxide are introduced into a pressure kneader and kneaded for obtaining a mixture for a composite magnetic body 1. Then, the mixture is rolled into a sheet-like composite magnetic body 1 by the use of rolls arranged in parallel. Magnesium hydroxide is used as the main component of flame retardant material, and when aluminum hydroxide, calcium sulfate hydrate, zinc borate hydrate or a mixture of them is used, the same manufacturing method is employed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composite magnetic body used for suppressing electromagnetic interference caused by interference of unnecessary electromagnetic waves in a high frequency range, and an electromagnetic interference suppressor using the same, and more particularly, to a composite magnetic body having a difficulty. The present invention relates to the reduction of the fire time after self-extinguishing in a burning prescription.

[0002]

2. Description of the Related Art In recent years, electronic devices utilizing high frequencies, such as mobile phones and personal computers, have become widespread. However, their weight, thickness, and size have been rapidly reduced, and the mounting density of electronic components on circuits has also increased. And the possibility of occurrence of electromagnetic interference due to electromagnetic interference between components and between circuit boards is extremely high. As a countermeasure against malfunction such as generation, leakage, and mutual interference of such unnecessary electromagnetic waves, a method of providing a shield to a noise generation source or inserting a choke or a filter in a noise transmission line has been adopted.

As one of the measures against the above-mentioned high-frequency electromagnetic interference, Japanese Patent Application Laid-Open No. 7-212079 discloses an electromagnetic interference suppressor. This is to dispose a sheet-like electromagnetic interference suppressor in which a soft magnetic material powder is dispersed in a binder near electronic components and circuits. It is suitable for a wide range of applications and has extremely high practicality.

However, since the composite magnetic material and the electromagnetic interference suppressor use an organic substance as a binder, once ignited, they do not have self-extinguishing properties and easily burn. . In view of the above, Japanese Patent Application Laid-Open No. H11-112229 discloses an electromagnetic interference suppressor provided with flame retardancy. This is a halogen-based (bromine-based) flame retardant
A compound and an inorganic flame retardant represented by antimony trioxide, a so-called flame retardant auxiliary, are added to the binder, and the combined effect of the halogen flame retardant and antimony trioxide is used.
Flame retardation is realized in the composite magnetic body and the electromagnetic interference suppressor.

[0005]

However, the flame retardancy of the composite magnetic material can be improved only by using a conventional flame retardant (bromine flame retardant) and an inorganic flame retardant (antimony trioxide) in combination. It can be difficult to provide. For example, a compound system in which the ratio of organic components is high in the compound composition of the composite magnetic material, and those in which the powder itself is active and energetically high in the type, particle size distribution, and surface state of the soft magnetic powder are flame-retardant,
In particular, there have been cases where self-extinguishing properties cannot be ensured.

Another problem is that even if the fire is barely extinguished, the fire time is long. If the fire time is long, there is a possibility that toxic gas may be generated, reignite, or the fire may be caused by the contact of the fire with any other organic material component or the like.

[0007] In the combustion test standardized by UL, the ignition time mentioned here means that after the ignition source is moved away from the test piece, or after the flaming combustion of the test piece is stopped, the specific condition is determined. It is the time during which the test piece sustains flameless combustion.

Further, in the prior art, the main purpose of imparting flame retardancy to the composite magnetic material is to extinguish flaming combustion.
No measures were taken to reduce fire time after the fire was extinguished. Here, as an example of the flame retardancy test, the content of the UL standard vertical flammability test is shown.
At 0, one of the conditions is that the sum of the combustion time and the ignition time after the second flame contact must be within 30 seconds. Therefore, in a blended composition having a long ignition time, these standards UL
It has been extremely difficult to conform to 94V-0.

In fact, the flame goes out after contact with the sample,
Since the fire remained for a long time, many cases of rejection occurred. In the case of such a composition, problems such as deterioration of the mechanical properties of the composite magnetic material, increase in raw material costs and increase in man-hours in the compounding process due to the addition of a flame retardant, and the like, increase the production cost. Had occurred.

[0010] Therefore, an object of the present invention is to provide a composite magnetic material having improved combustion resistance and an electromagnetic interference suppressor as compared with the prior art. Another object of the present invention is to provide a composite magnetic body and an electromagnetic interference suppressor in which the fire time after self-extinguishing is shortened.

[0011]

SUMMARY OF THE INVENTION In order to solve the above-mentioned technical problems, the present invention provides a composite magnetic material comprising a hydroxide, an inorganic hydrate, By using a mixture of a hydroxide and an inorganic hydrate, the ignition time is shortened.

That is, the present invention provides a composite magnetic material comprising a soft magnetic powder, a binder and a flame retardant, wherein the flame retardant or a part of the flame retardant is formed from one or both of a hydroxide and an inorganic hydrate. It is a composite magnetic material characterized by being constituted.

Further, the present invention is characterized in that in the composite magnetic material, the composition ratio of the flame retardant in the composite magnetic material is 1 to 1000 parts by weight with respect to 100 parts by weight of the binder. It is a composite magnetic material.

Further, the present invention is the composite magnetic material, wherein the flame retardant or a part of the flame retardant is made of magnesium hydroxide.

Further, the present invention provides the composite magnetic material, wherein the flame retardant or a part of the flame retardant is made of aluminum hydroxide.

Further, the present invention is the composite magnetic material, wherein the flame retardant or a part of the flame retardant comprises a mixture of magnesium hydroxide and aluminum hydroxide.

Further, the present invention provides the composite magnetic material, wherein the flame retardant or a part of the flame retardant comprises calcium sulfate hydrate.

Further, the present invention is the composite magnetic material, wherein the flame retardant or a part of the flame retardant is made of zinc borate hydrate.

Further, the present invention provides the composite magnetic material, wherein the flame retardant or a part of the flame retardant comprises a mixture of calcium sulfate hydrate and zinc borate hydrate. Body

The present invention also provides the composite magnetic material, wherein the binder is chlorinated polyethylene.

Further, the present invention is an electromagnetic interference suppressor characterized by using the above-mentioned composite magnetic material to suppress electromagnetic interference caused by interference of unnecessary electromagnetic waves.

[0022]

The inorganic compounds composed of ions include those containing water molecules in the form of hydrates. This water molecule exists as a crystal water in a state coordinated to a specific ion, and may contribute to stabilization of a crystal lattice.

Such water molecules vaporize at a higher temperature than free water, and hardly vaporize at room temperature. Therefore, when the flame retardant contains such water molecules, the water molecules are vaporized at the time of combustion, so that heat of vaporization is deprived, and the generated water vapor cuts off oxygen, thereby improving the flame retardancy.

Also, hydroxides dissociate water molecules at high temperatures,
The hydroxide itself changes to an oxide. For this reason, hydroxide can be expected to have the same effect as the above hydrate.

In view of the above, the present invention has studied to find a hydrate and a hydroxide which can improve the flame retardancy without impairing the properties such as the mechanical strength of the composite magnetic material. It is the result.

In the present invention, the composition ratio of the flame retardant in the composite magnetic material is 1 to 100 parts by weight with respect to 100 parts by weight of the binder.
The reason for this limitation is that if the flame retardant is less than this, the effect of the flame retardant is not recognized at all, and if the flame retardant is more than this, the mechanical strength of the composite magnetic material is reduced. This is to impair the characteristics such as.

In order to bind a large amount of powder with a small amount of a binder as in the present invention, the binder must have sufficient tackiness and flexibility. Suitable materials include chlorinated polyethylene.

[0028]

Embodiments of the present invention will be described below. The composite magnetic body functions as an electromagnetic interference suppressor that suppresses electromagnetic interference caused by interference of unnecessary electromagnetic waves when the composite magnetic body is used inside and around an electric device or the like. Therefore, in the present embodiment, the composite magnetic body treats the composition described below as an object obtained by the following method, and uses the obtained composite magnetic body inside and around an electric device or the like. In this case, it will be referred to as an electromagnetic interference suppressor. In other words, the composite magnetic body and the electromagnetic interference suppressor are the same when focusing on their constituent components and manufacturing process, but differ when focusing on their uses, and are described as different expressions. Therefore, hereinafter, where the composite magnetic body and the electromagnetic interference suppressor are described,
The terms are properly used for the above reasons.

The hydroxides and hydrates according to the present invention are, for example, those shown in the Dictionary of Physical and Chemical Sciences published by Iwanami Shoten, and are referred to as “generic names of compounds containing the atomic group OH” and “water molecules, respectively”. A molecular compound having a configuration formed by bonding to another molecule. "

[0030]

EXAMPLES Examples of a composite magnetic material, a method of manufacturing the same, and an electromagnetic interference suppressor according to the present invention will be described with reference to the tables.

(Example 1) As shown in Table 1, chlorinated polyethylene was used as a binder in an amount of 17% by weight, and soft magnetic powder having an average particle diameter of 35 μm and an aspect ratio of 5 or more was used.
65% by weight of an Al-Si alloy powder, 2% by weight of a titanate coupling agent, 10% by weight of magnesium hydroxide as a flame retardant, 3% by weight of a brominated polymer flame retardant, and antimony trioxide as a flame retardant aid. 3% by weight were weighed respectively. Table 1 also shows, as a comparison, an example not containing magnesium hydroxide.

[0032]

[Table 1]

First, the soft magnetic powder and the titanate-based coupling agent were charged into a stirrer and stirred for about 10 minutes until the soft magnetic powder became uniform, and the soft magnetic powder was previously subjected to a coupling treatment.

Next, the soft magnetic powder having been subjected to the coupling treatment, chlorinated polyethylene, magnesium hydroxide, a brominated polymer flame retardant, and antimony trioxide are charged into a pressure kneader and kneaded for about 10 minutes. Thus, an admixture for a composite magnetic material was obtained.

In the coupling treatment step, magnesium hydroxide, a bromine-based polymer flame retardant, and trioxide are used together with the soft magnetic powder to improve the flame retardant effect by improving the dispersion of the flame retardant and to improve the handling of the raw materials. Antimony may be charged into the stirrer and the surface treatment may be performed at the same time.

Next, the obtained mixture was passed through rolls arranged in parallel and rolled to obtain a sheet-shaped composite magnetic material.
In order to obtain a sheet-shaped composite magnetic material, extrusion molding, press molding, or injection molding may be used instead of the roll.

By using the composite magnetic material produced by the above method inside and around an electric device or the like, the composite magnetic material functions as an electromagnetic interference suppressor for suppressing electromagnetic interference caused by interference of unnecessary electromagnetic waves. I do.

[0038] Although an example using magnesium hydroxide as the main component of the flame retardant has been described above, the same applies to aluminum hydroxide, calcium sulfate hydrate, zinc borate hydrate, and mixtures thereof. It can be formed by a manufacturing method.

Next, the results of the vertical flammability test of Example 1 will be shown with reference to Table 2. Here, a test piece having a thickness of 1.0 mm was prepared for each of the composite magnetic material sheets without using the magnesium hydroxide prepared as a comparative example, those using the magnesium hydroxide of Example 1, UL
The comparison was made based on a 94V evaluation standard. For comparison, the blending compositions in the examples and comparative examples were the same blending ratio with respect to the binder except for magnesium hydroxide. For example, in the case of the soft magnetic powder and the binder, the ratio was set to the same condition that the soft magnetic powder was about 3.8 times the binder.

In the vertical combustion test, the sample No. 1 to No. Table 5 shows the burning time (sec) after the first flame contact in the column of the first flame contact, and the burning time (sec) after the second flame contact in Table 2. The fire time (seconds) after the flame of the sample was extinguished after the second flame contact was recorded in the column of the second flame contact.

[0041]

[Table 2]

As shown in Table 2, in the comparative example, the total fire time after self-extinguishing was 114 seconds, and the flame retardant standard UL94 was used.
It is a V-1 class. On the other hand, in the first embodiment, the total fire time after self-extinguishing is 47 seconds, which satisfies the V-0 class. That is, compared to the comparative example, the total fire time was 6 hours.
7 seconds, on average about 13 seconds.

Further, the total time of the first and second combustion times for the five samples, that is, the total of the combustion times of all 10 times is 26 seconds (<50 seconds). It is clear that the V-1 class of the comparative example has been improved to the V-0 class.

As a preliminary test, a brominated polymer flame retardant was added to the comparative example, and the blending ratio of the flame retardant was increased.
A similar test was performed, but no improvement was observed in the results of the vertical flame retardancy test due to the simultaneous increase in organic matter due to the addition of the flame retardant.

In this example, as shown in Table 1, 10% by weight of magnesium hydroxide, that is,
Although about 58.8 parts by weight of magnesium hydroxide is used based on 00 parts by weight, the addition amount of 1 to 1000 parts by weight with respect to 100 parts by weight of the binder is effective. Further, in consideration of the moldability of the composite magnetic material, the binder 10 is preferably used.
10 to 200 parts by weight per 0 parts by weight is appropriate.

(Embodiment 2) Next, a second embodiment will be described.
In Example 2, the coupling treatment, kneading, and molding were performed under exactly the same conditions as in Example 1 except that magnesium hydroxide, which was the hydroxide in Example 1, was changed to aluminum hydroxide. I got a sheet. Table 3 shows the results of the vertical combustion test in Example 2.

[0047]

[Table 3]

According to Table 3, the total fire time after self-extinguishing was 40 seconds, which was 74% from the result of the comparative example shown in Table 2.
Seconds. In addition, the first and second combustion times, that is, the total of the combustion times of all 10 times are 39 seconds (<50 seconds)
The improvement was seen from the V-1 class of the comparative example to the V-0 class.

(Embodiment 3) Next, a third embodiment will be described.
In Example 3, the binder, the soft magnetic powder, the coupling agent, the bromine-based polymer flame retardant, and the flame retardant aid were the same as in Example 1 in the composition of the composite magnetic material. The oxide was changed to a mixture of magnesium hydroxide and aluminum hydroxide at a weight ratio of 1: 1. The added weight of the hydroxide was the same as in Example 1. The same manufacturing conditions were used for comparison. Table 4 shows the results of the vertical combustion test in Example 3.

[0050]

[Table 4]

As compared with the comparative example shown in Table 2, in Example 3, the total fire time after self-extinguishing was 44 seconds, which was 70 seconds shorter than the comparative example. Further, the sum of the first and second burning times, that is, the total of the burning times of all 10 times is 35 seconds (<50 seconds), which is V-0 from the V-1 class of the comparative example.
Improvements have been made to the class.

(Embodiment 4) A fourth embodiment will be described. Also in this example, the same amount of binder, soft magnetic powder, coupling agent, bromine-based polymer flame retardant, and flame retardant auxiliary was used as in Example 1 in the composition of the composite magnetic material.
Then, only the hydroxide of the flame retardant was changed to calcium sulfate dihydrate, which is a hydrate-based flame retardant, and the added weight of the hydrate was equal to that of the hydroxide. The same manufacturing conditions were used for comparison. Table 5 shows the results of the vertical combustion test in Example 4. In addition, although hemihydrate exists also in calcium sulfate, since the effect of a flame retardant is so high that the amount of bonding of a water molecule is large, dihydrate was used in this Example.

[0053]

[Table 5]

(Embodiment 5) A fifth embodiment will be described. In this example, the binder, the soft magnetic powder, the coupling agent, the bromine-based polymer flame retardant, and the flame retardant aid were the same in the composition of the composite magnetic material as in Example 1;
The flame retardant hydroxide was changed to a hydrate type flame retardant. In Example 5, zinc borate hydrate was used, and the added weight of the flame retardant was equal. The same manufacturing conditions were used for comparison. Table 6 shows the results of the vertical combustion test in Example 5.

[0055]

[Table 6]

(Embodiment 6) A sixth embodiment will be described. In Example 6, a mixture of calcium sulfate hydrate and zinc borate hydrate at a weight ratio of 1: 1 was used as a hydrate-based flame retardant, and the compounding amount of each component and composite The method for adjusting the magnetic material sheet was the same as that in Example 1. In Table 7,
13 shows the results of a vertical combustion test in Example 6.

[0057]

[Table 7]

When Examples 4, 5, and 6 were compared with Comparative Examples, the total fire time of Example 4 after self-extinguishing was 48 seconds, which could be reduced by 66 seconds. Example 5
The total fire time was 55 seconds, which could be reduced by 59 seconds. In the sixth embodiment, the total fire time is 51 seconds, and 63
Seconds. Further, the sum of the first and second combustion times, that is, the total of 10 combustion times, was 40 seconds (<50) in Example 4.
Second), Example 5 is 48 seconds (<50 seconds), Example 6 is 41 seconds
Seconds (<50 seconds), and V-class from V-1 class of the comparative example.
The improvement was seen to the 0 class.

Further, even when at least one of the above-mentioned hydroxides and hydrates, which are flame retardants, is used in combination, a reduction in fire time after self-extinguishing was observed. In addition, since the burning time of the above embodiment was shortened, the amount of harmful gas generated by burning could be reduced.

FIG. 1 is a schematic view of a cross section in the thickness direction of the composite magnetic body of the above-described embodiment. The sheet 1 of the composite magnetic body includes a soft magnetic powder 3 in a binder 2 and a soft magnetic powder 3. This indicates that the fuel 4 is in a uniformly dispersed state.

[0061]

As described above in detail, according to the present invention, a composite magnetic material comprising a soft magnetic powder, a binder and a flame retardant is added to a hydroxide or an inorganic hydrate or a hydroxide and an inorganic water. By containing and dispersing the mixture of the sump, it is possible to improve the self-extinguishing property and to shorten the ignition time after self-extinguishing in the flame retardancy. Such a result cannot be easily obtained only by using a combination of a halogen-based flame retardant and a flame retardant auxiliary represented by antimony trioxide, which are widely used.

Further, the reduction of the burning time allows the reduction of the generation of harmful gas. Further, the composite magnetic sheet according to the present invention can secure the flame retardant standard UL94V-0 class. Therefore, the present invention contributes greatly to the improvement of the safety of electric and electronic devices.

[Brief description of the drawings]

FIG. 1 is a schematic view of a cross section in a thickness direction of a sheet of a composite magnetic body of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Composite magnetic body 2 Binder 3 Soft magnetic powder 4 Flame retardant

Claims (10)

[Claims] 1. A composite magnetic material comprising a soft magnetic powder, a binder and a flame retardant, wherein the flame retardant or a part of the flame retardant is composed of one or both of a hydroxide and an inorganic hydrate. A composite magnetic material characterized by the following. 2. The composite magnetic material according to claim 1, wherein
The composite magnetic body, wherein a composition ratio of the flame retardant in the composite magnetic body is 1 to 1000 parts by weight based on 100 parts by weight of the binder. 3. The composite magnetic body according to claim 1, wherein the flame retardant or a part of the flame retardant is made of magnesium hydroxide. 4. The composite magnetic body according to claim 1, wherein the flame retardant or a part of the flame retardant is made of aluminum hydroxide. 5. The composite magnetic body according to claim 1, wherein said flame retardant or a part of said flame retardant is composed of a mixture of magnesium hydroxide and aluminum hydroxide. body. 6. The composite magnetic body according to claim 1, wherein the flame retardant or a part of the flame retardant is made of calcium sulfate hydrate. 7. The composite magnetic body according to claim 1, wherein the flame retardant or a part of the flame retardant is made of zinc borate hydrate. 8. The composite magnetic material according to claim 1, wherein the flame retardant or a part of the flame retardant comprises a mixture of calcium sulfate hydrate and zinc borate hydrate. Characteristic composite magnetic material. 9. The composite magnetic body according to claim 1, wherein the binder is chlorinated polyethylene. 10. An electromagnetic interference suppressor using the composite magnetic material according to claim 1 to suppress electromagnetic interference caused by interference of unnecessary electromagnetic waves.