JPH0760892A - Composite sheetlike article - Google Patents

Abstract

PURPOSE:To provide a composite sheetlike article developing good magnetic shielding effect in the intensity of a wide range of a magnetic field. CONSTITUTION:A composite sheetlike article is obtained by forming a layer in which soft magnetic particles are uniformly present without leaving gaps on a base material by pressure bonding through a process scattering scaly or plate-shaped soft magnetic particles with a thickness of 5mum or less, an aspect ratio of 5 or more and a major axis diameter of 25mum or more over a base material whose polymeric resin is in a plasticized state and a process providing an adhesive layer composed of a polymeric resin on the base material in such a state that the base material is in a plasticized state.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet-like object for shielding DC and AC magnetism and magnetic field (hereinafter referred to as magnetic shield).

[0002]

2. Description of the Related Art In recent years, the influence of magnetic fields from electromagnets and permanent magnets on peripheral equipment has become serious. For example, the impact on pacemaker users in MRI (Magnetic Resonance Tomography) of hospitals, malfunction of electronic devices when using a loud sound system in a vehicle, and stainless steel due to magnetic leakage of an IH (electromagnetic induction heating) rice cooker. Problems have been pointed out such as the occurrence of overcurrent in the sink and the effects of magnetism in the coming linear motor car era. As a magnetic shield material that shields the magnetic field that causes the above-mentioned various problems, a soft magnetic material having a high relative magnetic permeability such as permalloy, sendust, and silicon steel, which has been subjected to sheet metal processing, has been widely used.

[0003]

Permalloy, silicon steel and the like are generally used as products obtained by processing a soft magnetic material into sheet metal, but these products have the following problems. That is, when distortion occurs due to bending, boring, etc., the magnetic alignment performance is reduced due to the disorder of the atomic arrangement. In order to eliminate the disorder of the atomic arrangement, a complicated process such as annealing in a high temperature (1100 ° C.) reducing gas after forming is required. Even if the product is commercialized, the magnetic shield performance will be reduced due to the distortion caused by the impact such as vibration and drop. (Cautious handling is required for handling).

There has been a demand for a magnetic shield material that replaces the sheet metal product having the above problems. Therefore, Mn-Zn ferrite, Cu-Zn ferrite, permalloy, sendust, silicon steel, amorphous alloy and the like have high relative magnetic permeability,
A magnetic shield material (hereinafter referred to as a resin binder magnetic shield material) formed by kneading and molding a soft magnetic powder having a low coercivity with a resin binder has been devised and used. However, in the case of a resin binder magnetic shield material, there is a problem that the ability to shield with a low magnetic field of 1 Oersted or less is poor because the resin wall exists between the powders even if the soft magnetic powder is highly filled.

In order to shield the magnetic field of 10 Oersted or more, even if a resin wall is present in the magnetic shield material such as the resin binder magnetic shield material, it does not matter so much. A strong magnetic field has a high density of lines of magnetic force per unit area, and therefore the probability that the lines of magnetic force collide with the soft magnetic particles increases in the strong magnetic field, and the majority of the lines of magnetic force are captured by the soft magnetic particles. The captured lines of magnetic force pass through the resin wall and are propagated to the adjacent magnetic particles. Propagation of magnetic force lines is repeated in the magnetic shield material, and finally the magnetic force lines return to the magnetic source. On the other hand, the magnetic force lines that can pass without being caught by the magnetic particles are stochastic, and the number of magnetic force lines that have passed is significantly larger than the number of magnetic force lines existing on the magnetic source side with respect to the magnetic shield material. Decrease. Thus
The space separated from the magnetic source by the magnetic shield material is magnetically shielded.

On the other hand, in a low magnetic field of 1 oersted or less, the density of magnetic field lines per unit area is low, and the magnetic field lines have a low probability of colliding with the soft magnetic particles. As a result, the number of magnetic force lines that have passed through the magnetic shield material does not significantly decrease with respect to the number of magnetic force lines existing on the magnetic source side with respect to the magnetic shield material. Therefore, the conventional resin binder-based magnetic shield material is not excellent in shielding in a low magnetic field of 1 Oersted or less.

[0007]

The present invention is a composite sheet material capable of solving the above problems. That is, the present invention, as described in claim 1 of the claims, has a thickness of 5 μm on a polymer resin base material in a plasticized state.
It is preferably 0.1 μm to 5 μm or less, the aspect ratio is 5 or more, preferably 100,000 or less (determined by the range of thickness and major axis diameter), and the major axis diameter is 25 μm or more, preferably 30 μm or less (if larger than this. The particles form the skeleton, and the flexibility of the resulting composite sheet is reduced.) Scale-like or plate-like soft magnetic particles are evenly dispersed and pressed to integrate the base material and soft magnetic particles. To provide a composite sheet-like product obtained by
In particular, soft magnetic particles are provided via an adhesive layer provided on a base material. Further, according to the present invention, as described in claim 2 of the present invention, the polymer resin base material is composed of a matrix of the polymer resin and the soft magnetic particles. The present invention provides the described composite sheet material. Further, the present invention, as set forth in claim 3 of the claims, claims 1 or 2
The present invention provides a composite sheet-like article, which is characterized by being formed by stacking the above described composite sheet-like articles in multiple stages.

The present invention will be described in detail below. Examples of the polymer resin used as the substrate or adhesive of the present invention include polyethylene, polypropylene, vinyl chloride resin, polyvinyl alcohol, vinylidene chloride resin, vinyl acetate resin, polyvinyl butyral, polystyrene, polymethyl methacrylate, polyacrylonitrile, Polyamide, polycarbonate, polyacetal, polyethylene terephthalate, polybutylene terephthalate, polyphenylene ether, polysulfone, polyamide imide, polyether imide, polyether sulfone, fluorine resin, thermoplastic resin such as cellulose resin, natural rubber,
IR, BR, SBR, NBR, CR, IIR, EVA,
Crosslinked rubbers such as urethane rubber, silicone rubber, fluorine rubber, acrylic rubber, chlorinated polyethylene, epichlorohydrin rubber, styrene-based and polyester-based thermoplastic elastomers, phenolic resins, melamine resins, aniline resins, unsaturated polyesters, diallyl phthalate resins Examples thereof include thermosetting plastics such as epoxy resin and alkyd resin, and these can be arbitrarily selected depending on the application, molding method or texture. If necessary, a thermoplastic such as vinyl chloride resin or vinyl acetate resin and dioctyl phthalate (DOP),
Mixtures of various plasticizers such as diisononyl phthalate (DINP), trimellitic acid type, pyromellitic acid type, polyester type, etc., mixtures of different resins, stabilizers, gelling agents, lubricants for these mixtures or the above resin alone. You may select from the mixture which adds etc.

The soft magnetic particles include Fe-Ni type alloy (permalloy) particles, Co-Fe amorphous particles,
Fe-Si-Al alloys (sendust), various soft ferrites, etc. can be listed. The composite sheet material according to claim 2 enhances the magnetic shield performance, and the polymer resin and the soft magnetic material particle mixture mentioned above are used as the base material. The blending ratio of the soft magnetic particles to the polymer resin is 5 to 5
It is desirable to set it in the range of 0% by volume. This is because the specific gravity of the Fe-Si particles, Co-Fe particles, Fe-Si-Al particles and the like is 6 to 8, and when the specific gravity of the polymer resin is 1.2 to 1.4, it is almost 20. Corresponds to ~ 80% by weight. For mixing, a method using a Hensiel mixer, a kneader, a kneading roll, or an extruder is effective.

The substrate of the present invention may have any shape, but is preferably in the form of a sheet or a film, and the molding method thereof includes calendering, extrusion, coating and the like.
Among the soft magnetic particles, scale-like or plate-like powder is used as a commercial product, and in particular, in the case of the composite sheet-like product according to claim 2, the mixture is used to plasticize the mixture in which the polymer resin is in a plasticized state. When the particles are deformed and oriented so that the flat surfaces of the particles and the surface of the molded body are substantially parallel to each other, the magnetic shield is efficiently performed. This makes it easier for the flat surface of the scaly or plate-like soft magnetic particles present in the base material to capture the lines of magnetic force. In order to produce a base material in which flaky or plate-like soft magnetic particles are oriented, a method of plastically deforming a mixture in a plasticized state is preferable.

In order to orient the flat surface of the particles and the surface of the molded body substantially parallel to each other, the particles are passed through two roll gaps. Pass through the extruder base. And the like.

In the method of (2), a kneading roll may be used as the two rolls, but as a mass-production method, a calender roll composed of a plurality of rolls is used, and the sheeting is performed so that the roll gap at the final stage is the narrowest. A method of gradually decreasing the thickness is preferable. In this case, a carrier sheet may or may not be used depending on the type of polymer resin. When a plate-shaped magnetic shield material is obtained by this method, the final product has, for example, a thickness of 2 to 3 mm.
Then, the thickness of roll sheeting is 0.3-0.4m
According to a method in which several m of the particles are superposed and integrated, the flat surface of the particles and the surface of the compact are easily parallel to each other and overlap each other.

In the method of allowing the particles to be oriented so that the flat surface of the particles and the surface of the molded body are substantially parallel to each other by passing through the die of the extruder, the die may be formed into a circular die, a T-die or the like. For example, in the case of molding using a T-shaped die, it is possible to orient the flat surface of the particles and the surface of the molded body so as to be substantially parallel in all regions. In this method, a method of stacking several thin extruded sheets to obtain a predetermined thickness, like the calender roll method, is desirable from the viewpoint of enhancing the magnetic shield effect.

In order to easily form the flat surface of the magnetic substance powder and the surface of the base material or the molded body of the adhesive layer on the base material substantially parallel to each other by spraying according to the present invention, the soft magnetic powder is formed into the above-mentioned shape. There is a need. This is because if the aspect ratio is less than 5, it is difficult to make the flat surface of the magnetic powder and the surface of the base material or the molded body of the adhesive layer on the base material substantially parallel to each other even if they are dispersed on the base material. Because. The powder having an aspect ratio of 5 or more can be obtained by processing substantially spherical particles obtained by a water atomizing method or the like into a scale shape by a mechanical means such as a ball mill or by solidifying a molten metal into a scale shape.

When the major axis diameter of the magnetic powder is less than 25 μm, the characteristics of the manufacturing method, the powder is unlikely to be scale-like or plate-like. Therefore, the major axis diameter of the magnetic powder used in the present invention must be 25 μm or more. Further, when using a magnetic substance powder having a major axis diameter of about 25 μm, the thickness of the powder needs to be 5 μm or less in order to obtain an aspect ratio of 5 or more.

The soft magnetic particles that are commercially available and have a scaly or plate-like shape include flat Co-Fe amorphous particles (manufactured by Mitsubishi Materials Corp.).
This satisfies the conditions that the aspect ratio is 5 or more and the thickness is 5 μmm or less, and the major axis diameter is 25 due to classification.
It is possible to obtain a powder having a size of μm or more.

The present invention is to spread scale-like or plate-like soft magnetic particles on a base material made of a polymer resin and an adhesive layer on the base material in a plasticized state. . The plasticized state of the polymer resin referred to here is a thermoplastic resin or a rubber-based elastomer, a softening point or a melting point, a plasticized state, a thermoplastic resin, a thermosetting resin in an uncrosslinked state and A state where the rubber-based elastomer is dissolved in a solvent or the like and is plasticized, a state where the polymer paste is plastisol or latex and is plasticized,
A liquid or clay-like polymer resin, or a liquid or clay-like uncrosslinked thermosetting resin. Both of them have an adhesive ability when they are in a plasticized state, and this property is used to fix the soft magnetic particles.

When the plasticized state is, the base material or the adhesive layer on the base material is heated by a heater, an oven, etc.,
Immediately after plasticization, the soft magnetic particles are sprayed. When the plasticized state is or, if the polymer resin has low viscosity, it is soft before being solidified by forming the base material or the adhesive layer on the base material by doctor coating, gravure printing, screen printing, etc. Scatter magnetic particles. ,
In the case of, when the polymer resin has a high viscosity, the base material or the adhesive layer on the base material is prepared by die coating, calendering, etc., and the soft magnetic particles are dispersed before solidification. Is good.

The method of spraying the soft magnetic particles may be any method such as a mechanical method or a manual method. After the spraying, in order to integrate the base material and the soft magnetic material particles by pressure bonding, any method such as pressure bonding with an embossing roll and a back roll or pressure bonding with a pressing machine may be used. In order to form a layer in which the soft magnetic particles are present on the base material or the adhesive layer on the base material without any gap, it is preferable to remove the excess soft magnetic material particles after excessively dispersing the soft magnetic material particles. . The ideal process is to spread the soft magnetic particles excessively and integrate them with the base material or the adhesive layer on the base material by pressure bonding,
This is a method of removing excess magnetic particles and collecting them. Further, the magnetic shield performance can be remarkably improved by stacking layers in which magnetic particles are dispersed in multiple stages. In the present invention, the layer obtained by spraying is ideally such that the particles are laminated uniformly and without a gap, and the spraying weight per unit area is the same area weight of a film made of the same material as the particles and having the same thickness. be equivalent to. The weight is given by the product of the specific gravity (g / cm ³ ) of the particles to be sprayed and the 50% average thickness (cm) of the particles, and this may be used as a standard spraying weight. However, in practice, it is difficult to spray without gaps, and it is necessary to stack so that at least all the particles are overlapped with a part of the adjacent particles. Even if there is a gap, there is no problem as long as the target magnetic shield performance is exhibited, and if the target magnetic shield performance is not reached due to the presence of the gap, it is preferable to use multiple lamination as in claim 3. good. The magnetic shielding performance of the composite sheet material of the present invention depends on the amount of the soft magnetic material particles dispersed, and in order to ensure the reliable performance value of the sheet material, the dispersion of the soft magnetic material particles is performed. Must be done uniformly. In order to control the uniformity of the particle application, it is best to confirm the amount applied per unit area by weight. In addition, in order to perform uniform stacking by spraying, it is difficult to maintain accuracy compared to stacking by coating, printing, etc., so the spread weight per unit area is less than the target spread weight by ± 5%
Within, preferably within ± 2.5%.

[0020]

EXAMPLES The embodiments of the present invention will be specifically described with reference to Examples.

(Performance Evaluation Method for Magnetic Shielding Material) A sheet-shaped magnetic shield material having a width of 120 mm and a length of 120 mm placed at the center of the bottom surface of a paper box, and a permanent magnet placed vertically below the magnetic shield material. To give a magnetic field of 100 Oersted, 50 Oersted, 10 Oersted, 1 Oersted and set it at a position 100 mm directly above the permanent magnet (vertically above the magnetic shield material) for low magnetic fields.
The strength of the magnetic field attenuated by M-DGML5 type [trade name of Mitec Co., Ltd.] is measured. Using this value as r and the measured value of the magnetic field strength in the absence of the magnetic shield material as R (blank), the performance value F of the magnetic shield material was calculated by the following formula, and the magnetic shield material was calculated from this value. The performance of the material was evaluated. ..F = (1-r / R) × 100

Example 1 Vinyl chloride resin T by suspension polymerization having an average degree of polymerization of 1000
100 parts by weight of K-1000 [trade name of Shin-Etsu Chemical Co., Ltd.], 100 parts by weight of dioctyl phthalate as a plasticizer, 900 F Ba-Sn stabilizer [Akishima Chemical Co., Ltd.]
Product name] 3 parts by weight was dried up with a Henschel mixer, and this was processed into a sheet having a thickness of 0.30 mm through a kneading roll and a calendar process. On this sheet, vinyl chloride resin PSL-2 obtained by emulsion polymerization with an average degree of polymerization of 750
80 [trade name of Kanegafuchi Chemical Industry Co., Ltd.] 100 parts by weight, dioctyl phthalate as plasticizer 50 parts by weight, stabilizer A
C-212 [trade name of Asahi Denka Kogyo Co., Ltd.] was stirred with a disper mixer to obtain an average of 50 g / m ² of a plus sol paint by screen printing, which was used as an adhesive layer. Next, a flat Co-Fe-based amorphous particle (manufactured by Mitsubishi Materials Corp.) having a thickness of 2.5 to 3.0 μm and a 50% particle diameter of the biaxial average diameter of 85 μm is placed in a container and manually And the amorphous particles were sprinkled on the adhesive layer at about 200 g / m ² by moving it vertically and horizontally. After spraying, let the amorphous particles come into close contact with the adhesive layer by passing between an embossing roll with a clearance set to 0.20 mm and a rubber back roll, and then apply vibration to prevent the amorphous particles from coming into close contact with the adhesive layer. The particles were dropped. At this time, the particles remained about 150 g / m ² on the adhesive layer. Then, in an oven heated to 140 ° C, 60
It was sealed for 2 seconds, and the adhesive layer made of plus sol was gelated to obtain a composite sheet. This composite sheet-like material was divided into eight parts, and an eight-layer integrated sheet-like material was obtained by a pressing machine. The obtained sheet-like material was composed of 8 layers in which amorphous particles were present without gaps (± 1.0% or less). This was measured according to the magnetic shield performance evaluation method described above, and the results shown in Table 1 were obtained. As shown in Table 1, the magnetic shield performance in the low magnetic field (1 Oersted) was not inferior to the magnetic shield performance in the high magnetic field (10 to 100 Oersted).

[0023]

[Table 1]

Example 2 Vinyl chloride resin TK-1000 having an average degree of polymerization of 1000
[Shin-Etsu Chemical Co., Ltd. product name] 100 parts by weight, 100 parts by weight of dioctyl phthalate as a plasticizer, Ba-Sn
System stabilizer 900F (trade name of Akishima Chemical Co., Ltd.) 0.5 to 1.0 parts by weight in 100 parts by weight of a mixture of 3 parts by weight
μm, 50% of the biaxial average diameter of 85 μm, flattened Co-Fe based amorphous particles (manufactured by Mitsubishi Materials Co., Ltd.) 300 parts by weight were blended and kneaded with a hot roll at 155 ° C. A mixture containing 75% by weight (33% by volume) of Fe-based amorphous particles was obtained. Then, from this mixture, a kneading roll and a calendering process were performed to obtain a thickness of 0.6.
A mm mixture sheet was obtained. When the obtained mixture sheet was cut and the cross-section was observed, it was observed that the flat surfaces of the amorphous particles were arranged substantially parallel to and overlapped with the sheet surface. Four layers of this mixture sheet were laminated and integrated by a pressing machine to obtain a sheet-like material having a thickness of 2.0 mm. This is a comparative example A sheet for the example of the present invention. On the other hand, the mixture sheet has a thickness of 0.
It was placed on a 1 mm polyethylene terephthalate carrier sheet and heated by a far infrared heater to plasticize the vinyl chloride resin constituting the mixture sheet. Next, the mixture sheet was taken out together with the carrier sheet, and the flat Co-Fe based amorphous particles were sprayed at a rate of 200 g / m ² . After spraying, the amorphous particles were brought into close contact with the adhesive layer by passing between an embossing roll and a rubber back roll with a clearance set to 0.20 mm, and then vibration was applied to drop the particles that were not in close contact. . As a result, the particles on the adhesive layer were about 150 g / m ² (± 0.2
%) To obtain the remaining composite sheet. This composite sheet material was divided into four, and the divided composite sheet material was pressure-bonded into four layers by a press machine to obtain an integrated sheet material. This is designated as Example B sheet of the present invention. Obtained A
The sheet and the B sheet were measured and evaluated by the above-mentioned magnetic shield performance evaluation method, and the results shown in Table 2 were obtained.

[0025]

[Table 2]

As shown in Table 2, the B sheet of the present invention was not inferior in the magnetic shield performance in the low magnetic field (1 Oersted) to the magnetic shield performance in the high magnetic field (10 to 100 Oersted). . On the other hand, in the A sheet of the comparative example, the magnetic shield performance in the low magnetic field (1 Oersted) tended to be considerably lower than the magnetic shield performance in the high magnetic field (10 to 100 Oersted).

[0027]

EFFECTS OF THE INVENTION By forming scaly or plate-like soft magnetic particles satisfying the conditions specified in the present invention on a base material or an adhesive layer on the base material, a layer present uniformly without gaps is formed. It is possible to obtain a composite sheet-like material exhibiting a good magnetic shield effect in a wide range of magnetic field strength.

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[Procedure amendment]

[Submission date] September 10, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0007

[Correction method] Change

[Correction content]

[0007]

The present invention is a composite sheet material capable of solving the above problems. That is, the present invention, as described in claim 1 of the claims, has a thickness of 5 μm on a polymer resin base material in a plasticized state.
Preferably not more than an aspect ratio below 0.1μm~5μm 5 or higher, preferably 100,000 or less and the long axis diameter (thickness determined by the scope of the major axis diameter) is more than 25μm and preferably below 30 m m (from which If it is large, the particles become a skeleton, and the flexibility of the resulting composite sheet-like product is reduced), and the flaky or plate-like soft magnetic particles are evenly dispersed and pressed to form the base material and the soft magnetic particles. It is intended to provide a composite sheet-like product obtained by integration.
In particular, soft magnetic particles are provided via an adhesive layer provided on a base material. Further, according to the present invention, as described in claim 2 of the present invention, the polymer resin base material is composed of a matrix of the polymer resin and the soft magnetic particles. The present invention provides the described composite sheet material. Further, the present invention, as set forth in claim 3 of the claims, claims 1 or 2
The present invention provides a composite sheet-like article, which is characterized by being formed by stacking the above described composite sheet-like articles in multiple stages.

Claims (3)

[Claims] 1. A polymer resin base material in a plasticized state, having a thickness of 5 μm or less, an aspect ratio of 5 or more, and a major axis diameter of 2.
A composite sheet-like product, characterized in that scale-like or plate-like soft magnetic material particles having a size of 5 μm or more are uniformly dispersed and pressure-bonded to integrate the base material and the soft magnetic material particles. 2. The composite sheet material according to claim 1, wherein the polymer resin base material is a mixture of a polymer resin and soft magnetic particles. 3. A composite sheet-like product, comprising a multi-layered stack of the composite sheet-like products according to claim 1.