JPH0833456B2 - Film for magnetic labels - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a film for a magnetic marker recognizable by a magnetic sensor.

(Prior art) Unmanned vehicle guidance systems or blind guidance systems in factories, various venues, or on general roads have been developed. However, these systems are based on differences in magnetic permeability and easiness of magnetization. It is composed of a combination of a magnetic sensor (for example, see Japanese Patent Application Laid-Open No. 61-230073) for recognizing and identifying a marker containing a soft magnetic material and the aforementioned marker. In this system, a marker is buried on a floor or a passage, a soft magnetic material is detected by a magnetic sensor, and an unmanned vehicle or a blind person is instructed on a traveling direction or a passage.

 Ferrite has been used as a marker.

In addition to the marker using such a ferrite sheet, a method of commercializing a method of mixing a soft magnetic material powder and a paint, coating the mixture on roads and floors and laying the magnetic marker is commercialized. In addition, Japanese Patent Application Laid-Open No. 63-157210 proposes that a high-permeability metal magnetic tape be provided along a road surface.

(Problem to be Solved by the Present Invention) Mixing powder of a soft magnetic material as a pigment into a binder or paint to form a paint, and applying this is technically the simplest method of laying a magnetic marker. Is the way.

However, the laying of magnetic markers by this method,
Since the amount of the soft magnetic powder greatly affects the sensitivity of the magnetic sensor, it is necessary to control the amount of the powder with high accuracy.
In addition, when a coating material is formed, the soft magnetic material powder sediments, so that it is necessary to sufficiently stir the soft magnetic material powder before coating to uniformly disperse the soft magnetic material powder. Even if the application is performed with the stirring operation being performed reliably, as shown in FIG. 1, if the actual application surface has irregularities, the coating film thickness will differ depending on the irregularities of the application surface. This means that the amount of the soft magnetic powder varies depending on the unevenness of the coated surface, which greatly affects the sensitivity of the magnetic sensor. That is, the output of the magnetic sensor with respect to the marker shown in FIG. 1 is represented by a graph (displayed as paint) in the upper part of FIG. 3, and the output varies greatly.

On the other hand, the method using the high-permeability metal magnetic tape solves the problem of the difference in coating thickness caused by the unevenness of the coated surface in the above-described method using the paint, but the high-permeability metal magnetic tape is expensive. In addition, in the construction, it is necessary to further laminate and use a sheet mainly composed of a binder and a body made of synthetic rubber or synthetic resin, which is problematic in terms of economy.

Therefore, an object of the present invention is to solve the above-mentioned disadvantages of the related art.

(Means for Solving the Problems and Their Functions) In order to solve the above-mentioned problems, the present invention basically provides a sheet-like film having a uniform thickness by mixing a mixture of a thermoplastic resin and a soft magnetic powder. Adopt the means described above. This film is heat-welded to a road or a floor to form a magnetic marker.

That is, the soft magnetic powder and the plastic are mixed using a solvent or mixed by heat melting, formed into a sheet shape, and then cut into a predetermined shape to obtain a band-shaped or film-shaped marker. As a plastic used at this time, a thermoplastic resin such as vinyl chloride, polyester, urethane, or acrylic is used. Fe-Si-
An ingot is manufactured by melting an Al-based alloy by electroslag melting or high-frequency melting, and pulverized by a stamp mill or a vibrating ball mill to use a powdered and granular material. In this case, the alloy composition is such that, by weight, the composition of the base is Fe ≧ 77%, 5% ≦ Si ≦ 11%, and 2% ≦ Al ≦ 7%. However, one or more of Ni, Ti, Cr, Mn, Co, Mo, V, B, and C may be added as an additional element for improving magnetic properties or corrosion resistance with a total upper limit of 5%. .
Ti, Cr structure corrosion resistance, Ni, Mn, Co, Mo, V, B,
C has the effect of slightly improving the magnetic properties (square or initial permeability). Within this composition range, the magnetic permeability is large, and the magnetic properties are further improved by the heat treatment, and at the same time, a coating of a composite oxide of Fe, Si, and Al is formed on the surface, and the corrosion resistance is also improved.

Next, the powder is pulverized into a granular powder by a stamp mill and a vibration mill. In this case, the larger the particle size, the better the soft magnetic characteristics and the lower the cost in terms of magnetic properties. However, for use as a film, the practical upper limit is about 3 mm. On the other hand, when the particle size is 5 μm or less, the coercive force increases and the soft magnetic properties are impaired, so that it is not preferable that the ratio increases. When the particle size distribution is concentrated in a narrow range of the specific particle size range, the space factor of the magnetic material (5
%), Which is not advantageous when used as a label because the required weight of the magnetic material increases. A suitable particle size distribution should be at least 5 μm to 3 mm.
Must contain at least 0%. Further, if the thickness of the film exceeds 3 mm, when the film is welded to a floor or a road, the film tends to be flat without irregularities along the floor or the road surface. Therefore, the thickness of the film is set to 0.10 to 3 mm.
As long as the above obtained composition and particle size range, even without heat treatment described below, 0.10 ~
If the film is 3 mm thick, it will be sufficiently sensitive to a magnetic sensor that uses a relatively weak excitation field, such as one driven by a dry cell.

However, in the heat treatment of maintaining the above composition and particle size range in a temperature range of 200 ° C. to 1000 ° C. in an oxidizing atmosphere, a composite oxide of Fe, Si, and Al is formed as a film on the particle surface, The corrosion resistance is improved and the magnetic permeability in the frequency range above 1 KHz is also improved. At this time, the magnetic characteristics are not deteriorated due to the formation of the oxide film, but rather, the eddy current loss is reduced, and the magnetic characteristics in the frequency range of 1 KHz or more are improved. When the alloy powder prepared as described above is mixed with plastic or mixed with an appropriate binder to form a film and is welded to a road surface or a floor, the thickness of the film is reduced to about 0.10 to 3 mm. 1KHz-1MHz
Magnetization that can be detected in the frequency range is obtained.

When the strip-shaped plastic film in which the magnetic powder is uniformly dispersed in advance is heated by a burner or the like and thermally fused to the road surface, as shown in FIG. 2, the film is fused in a layer along the unevenness of the road surface. Therefore, the thickness of the magnetic layer is averaged,
Variations in performance of the finally formed marker can be suppressed. In this case, irregularities are formed on the surface after the heat fusion. However, in this case, there is no problem because the irregularities are not usually larger than the irregularities on the road surface. Further, in the case of heat fusion, since the adhesive strength is immediately developed as soon as the sheet is heated and then cooled, there is an advantage that the application can be completed in a short time as compared with a long drying time in the case of a paint. .

(Example) A mixture of polyurethane resin 1 and magnetic powder 1 was mixed into a solvent to form a paint, a release agent was applied on a smooth Al plate, the above-mentioned paint was applied thereon, and then dried. The sheet is peeled off from the plate to form a sheet-like molded body having a thickness of 1 mm. This was thermally fused to the asphalt road surface with a burner to form a band-shaped marker. The magnetic powder used was Fe ₈₅ -Si _9.5 Al _5.5 alloy having an average particle diameter of 63 μm. The output when the AC magnetic sensor is moved along the surface of the marker is shown in FIG. 3 as the product of the present invention. Compared with the conventional example shown in FIG. 3, the output variation of the example of the present invention is extremely small.

(Effect) In the present invention, the amount of the soft magnetic material powder can be adjusted by the thickness of the film, so that the film can be selected according to the laying surface and the sensor.

In addition, if the laying surface is selected according to the characteristics of the plastic, for example, wear is small even in places where there are many vehicles.

[Brief description of the drawings]

FIG. 1 is a sectional view of a laying surface of a conventional example, FIG. 2 is a sectional view of an example of the present invention, and FIG. 3 is a graph showing sensor outputs of the present example and a conventional example.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masahiro Kato 810 Kumagaya, Kumagaya-shi, Saitama Riken Kumagaya Plant (72) Inventor Minoru Seshita 1-13-5 Kudankita, Chiyoda-ku, Tokyo Riken Co., Ltd. (56) References JP-A-62-180287 (JP, A) JP-A-63-157210 (JP, A) JP-A-60-40876 (JP, U)

Claims (2)

[Claims] A mixture of a thermoplastic and an Fe-Si-Al-based alloy powder containing at least 50% or more of particles having a particle size in the range of 5 to 3 mm is made into a 0.10 to 3 mm sheet-like film, and the film is used as a floor surface. For magnetic markers, which is heat-sealed to roads and roads. 2. The film according to claim 1, wherein the thermoplastic is selected from vinyl chloride, polyester, urethane and acrylic.