JP5877804B2 - Magnetic layer of building member and method for manufacturing magnetic layer of building member - Google Patents

Description

  In the present invention, a magnetic layer capable of magnetically attracting a permanent magnet is formed on a surface of a building member such as an existing wall, pillar, door, board, or partition by coating. The present invention relates to a magnetic layer of a building member that suppresses generation of rust while ensuring (magnetic adhesion).

A paint mixed with iron powder is applied to a wall or a plate several times to form a surface on which a magnet is adsorbed (Patent Document 1), or a resin mixed with iron powder is used as an adhesive (Patent Document 2) ) Etc. have been many since ancient times.
However, magnetic powder such as iron powder is simply mixed, and the same paint is applied several times, and there has been no technical progress until today.

  In Patent Document 3, reduced iron powder having an average particle size of 10 to 60 μm (microns) is mixed into a paint to form a coating film, thereby forming a magnetized surface.

Japanese Utility Model Publication No. 42-009236 Japanese Utility Model Publication No. 63-144684 JP 2011-79996 A

However, each painted surface according to these prior arts comes into contact with moisture in the atmosphere and rust is generated. Outdoors are out of the question, but even indoors, condensation and dirt are often wiped with a rag or children are exposed to water, and sooner or later rust is generated.
As for the generation of rust, the iron powder near the surface starts to rust first and spreads to the inside.

On the other hand, the iron powder used has a relatively large particle size for the purpose of improving cost and magnetizing force. When the average particle size exceeds 100 microns, the roughness becomes rougher due to the roughness of the painted surface, and when it reaches 150 to 160 microns, the magnetic material on the rough surface becomes sparse so that the magnetic field due to the permanent magnet is reduced. Wearing power will decrease.
Therefore, for the purpose of improving the appearance and increasing the magnetizing force, even if the average particle diameter of the iron powder is about 100 microns, it is possible to polish the rough magnetic coating surface to be flat and to apply a non-magnetic finish coating thereon. is there.

  If the thickness of the nonmagnetic coating is increased, the occurrence of rust can be delayed, but the magnetizing force is greatly reduced. On the other hand, if the thickness of the coating is reduced in order to ensure the magnetizing force, there is a problem that as a result, the penetration of moisture and air is quick and the generation of rust is accelerated.

In the painting process, the surface of the building member may be undercoated. This is in order to allow the paint to sufficiently adhere and adhere to the surface of the member while protecting the surface, but the resin composition of the undercoat material may be different from or the same as that of the resin of the present coating.
Conventionally, the undercoat has adopted a paint that does not contain a magnetic material. Accordingly, since the portion corresponding to the thickness of the undercoat material does not include a magnetic material, the magnetizing force is inferior when compared with the overall coating thickness.
Adopting an undercoat containing iron powder makes it easier to secure the magnetic adhesion force, but since there is a lot of iron powder in the layer near the building member surface, moisture and air are supplied through the member, and iron powder rusts. Since it progresses, it is not preferable.

Therefore, the present invention provides a magnetic layer for a building member and a method for producing a magnetic layer for a building member that prevent a problem that the iron powder rusts while preventing a decrease in the high magnetic adhesion force obtained by mixing the iron powder with the paint as much as possible. The task is to do.

In order to solve this problem, a magnetic layer of a building member according to the present invention is a magnetic layer having magnetism applied to the surface of a building member such as a wall, a pillar, a door, a board, or a partition. A magnetic main layer formed of a magnetic coating for a magnetic main layer in which a magnetic powder mainly composed of iron powder is mixed with a coating binder on the surface of the member, and soft ferrite powder, magnetite powder, hard ferrite powder in the coating binder and Table magnetic barrier layer formed by one or more tables magnetic barrier layer for magnetic coating material obtained by mixing a magnetic powder selected from the group consisting of is characterized in that it is laminated.

In the magnetic layer of the building member, a magnetic material composed of one or more mixtures selected from the group consisting of soft ferrite powder, magnetite powder, and hard ferrite powder as a coating binder between the surface of the building member and the main magnetic layer. A back magnetic barrier layer formed of a magnetic coating material for the back magnetic barrier layer mixed with powder may be interposed.

The manufacturing method of the magnetic layer of the building member according to the present invention is a method of manufacturing the magnetic layer of the building member according to the present invention, wherein the surface magnetic barrier layer is formed on the polished surface after polishing the upper surface of the magnetic main layer. It is characterized by laminating .

The surface magnetic barrier layer is contacted with a paint binder for the first time in a container that has been degassed and decompressed in advance, with one or more magnetic powders selected from the group of dried soft ferrite powder, magnetite powder, and hard ferrite powder, Thereafter, the magnetic coating material for the surface magnetic barrier layer that has been subjected to the step of returning the pressure to atmospheric pressure may be dried after being coated and laminated .

The back magnetic barrier layer is contacted with a coating binder for the first time in a container that has been deaerated and decompressed in advance, with one or more magnetic powders selected from the group consisting of dried soft ferrite powder, magnetite powder, and hard ferrite powder. Then, it is preferable to laminate the magnetic coating material for the back magnetic barrier layer that has been subjected to the step of returning the pressure to atmospheric pressure after the coating and then drying.

The magnetic main layer is a magnetic main layer that has been subjected to a process of bringing a magnetic powder mainly composed of dried iron powder into contact with a paint binder for the first time in a previously deaerated and depressurized container and then returning the pressure to atmospheric pressure. It is preferable to laminate the magnetic paint after drying it.

  According to the present invention, a magnetic layer for securing a necessary magnetic adhesion force while preventing a decrease in high magnetic adhesion force obtained by mixing iron powder into a paint as much as possible and preventing a problem that iron powder rusts can be used as an arbitrary building member. Can be formed on the surface.

  That is, according to the present invention, the major part of the magnetic layer is a magnetic main layer mainly composed of iron powder having a high magnetic adhesion force, and the surface magnetic barrier layer is disposed so as to cover the magnetic main layer. Further, a back magnetic barrier layer can be provided on the back surface of the magnetic main layer. The two barrier layers were composed of magnetic powder that does not proceed with oxidation chemically. As a result, the high magnetic adhesion of the magnetic main layer was utilized, and it acted as a barrier to prevent moisture and oxygen from penetrating into the magnetic main layer, thereby preventing iron powder from rusting in the magnetic main layer.

  In addition, the surface of the magnetic main layer is polished and smoothed, and then the surface is covered with a surface magnetic barrier layer mainly composed of magnetic powder that does not rust, so that the surface of the magnetic layer is smoothed and improved in appearance. It was possible to secure and improve the adhesion and to suppress the occurrence of rust.

  Furthermore, the present invention is a process in which when magnetic powder such as iron powder is brought into contact with the paint binder for the first time, the magnetic powder is dried in advance, and is first brought into contact with the paint binder under deaeration and reduced pressure, and then returned to normal pressure. As a result, it was possible not only to remove moisture and oxygen from the surface of the magnetic powder, but also to wet the fine spaces formed by the aggregation of fine powder and the voids in the iron powder with the paint binder, thus promoting the dispersion of the magnetic powder. Not only was it possible, but it was possible to further prevent rusting.

1 shows a cross-sectional view of a magnetic layer that represents one example of an embodiment of the present invention. FIG. 3 shows a cross-sectional view of a magnetic layer representing an example of another embodiment of the present invention. Sectional drawing of the conventional magnetic layer is shown. 1 shows a schematic diagram illustrating a method of bringing a paint binder into contact with magnetic powder under deaeration and reduced pressure. The electron micrograph of reduced iron powder is shown.

  The present invention relates to a magnetic layer composed of a magnetic main layer formed by using a magnetic paint mainly composed of iron powder and a layered structure based on front and back magnetic barrier layers disposed on the front and back of the magnetic main layer. The purpose of this is to prevent the iron powder from rusting while ensuring the magnetizing force, and will be described in detail in the following embodiments.

The part indicated by reference numeral 3 in FIG. 1 or reference numeral 3 in FIG. 2 is a magnetic main layer formed of a magnetic paint mainly composed of iron powder, and is a layer mainly responsible for magnetism adsorbed by the magnet. .
The magnetic powder of the magnetic main layer contains soft ferrite powder, magnetite powder, or hard ferrite powder in addition to iron powder, but the magnetic adhesion is ensured, but the higher the ratio of iron powder, the higher the magnetic adhesion. The iron powder ratio is most preferably 100%, and preferably 80% by weight or more.
In the present invention, a general term for iron powder, soft ferrite powder, magnetite powder, and hard ferrite powder is referred to as magnetic powder.

The front magnetic barrier layer 4 is formed on the surface of the magnetic main layer 3, and the back magnetic barrier layer 5 is formed between the back surface of the magnetic main layer and the surface of the building member.
The front magnetic barrier layer and the back magnetic barrier layer have a barrier function that prevents moisture, oxygen, or other chemical components from entering or moving into the coating film after the magnetic layer of the present invention is completed. The front magnetic barrier layer and the back magnetic barrier layer have a function of significantly delaying the time until moisture or oxygen acts on the iron powder of the magnetic main layer to rust the iron powder.

The surface magnetic barrier layer does not contain iron powder, and magnetite powder or ferrite magnetic powder is a magnetic component. Therefore, although the magnetic adhesion force is slightly less than when iron powder is used, it has strong magnetism.
Therefore, the surface magnetic barrier layer forms a magnetic circuit when the magnet approaches, and plays a role of guiding the magnetic properties of the iron powder of the magnetic main layer to the surface magnetic barrier layer surface, so that the strong magnetic adhesion force of the magnetic main layer is greatly impaired. There is no. That is, a stronger magnetic adhesion can be ensured as compared with the case where the magnetic powder is removed from the surface magnetic barrier layer to obtain a simple surface barrier layer.

The back magnetic barrier layer does not contain iron powder, and magnetite powder or ferrite magnetic powder is a magnetic component. Therefore, although the magnetic adhesion force is slightly less than when iron powder is used, it has strong magnetism.
The back magnetic barrier layer has the effect of increasing the thickness of the magnetic main layer. That is, compared to the case where there is no back magnetic barrier layer, there is an effect of increasing the magnetizing force.

  Since one of the objects of the present invention is to secure a magnetic adhesion force close to that when only iron powder is used, the surface magnetic barrier layer may have a minimum thickness necessary for ensuring a function as a barrier layer. Even if the back magnetic barrier layer is made thicker than necessary, the effect of improving the magnetic adhesion is not significant.

A typical application of the magnetic layer of the present invention is to use thin and light pamphlets and memos sandwiched between magnets for posting, so that the magnetic adhesion force is 0.15 N (Newton) / cm ² (cm Square) is enough.
On the other hand, when a magnet having a thickness of 1.0 mm, a magnetization pitch of 2.5 mm, and a surface magnetic flux density of about 35 to 40 mT (milli-Tessler) is adopted as the magnet to be magnetically attracted, the thickness of the magnetic main layer is 0. It was found that a magnetic adhesion force of 0.15 N / cm ² can be achieved with about 3 mm or more.
On the other hand, the thickness of the surface magnetic barrier layer is defined by the particle size of the magnetic powder contained and the necessary barrier properties. In consideration of coating uniformity and pinholes, a thickness of about 0.05 to 0.1 mm is usually employed.

When the above experimental fact is applied to the present invention, the ratio of the thickness of the magnetic main layer to the thickness of the surface magnetic barrier layer becomes (0.3 or more): (0.05 to 0.10). The thickness of the layer is preferably at least 3 times that of the surface magnetic barrier layer.
When the magnetic layer of the present invention requires a stronger magnetizing force, the thickness of the magnetic main layer may be increased.

The magnetic coating used in the present invention is more preferably obtained by the following method in addition to the conventional method in which the magnetic powder and the coating binder are simply mixed at atmospheric pressure.
That is, when mixing the magnetic powder and the paint binder, the previously dried magnetic powder and the paint binder are brought into contact with each other for the first time in a previously deaerated and decompressed container, the magnetic powder is wetted with the paint binder, and then the pressure is increased. Adopt magnetic paint that has undergone a procedure to return to atmospheric pressure. When adding an anti-settling agent or the like, it is preferable to mix it with a paint binder in advance.

The degassing / depressurization step described above removes the moisture and air on the surface of the magnetic powder and the voids in the magnetic powder, or the moisture and air contained in the paint binder. Furthermore, there is an effect that fine bubbles remain inside the fine magnetic powder and the wetness between the magnetic powder and the coating binder becomes insufficient, thereby eliminating the problem of deteriorating the dispersion of the magnetic powder. In addition, the compatibility between the magnetic powder and the paint binder is improved to prevent the generation of voids on the surface of the magnetic powder after painting and drying, thus eliminating the occurrence of pinholes after painting and improving the barrier effect. It has an effect of preventing deterioration of mechanical properties, and is suitable.
It is preferable to knead the paint binder and the magnetic powder after mixing to promote mixing regardless of the presence or absence of the degassing / depressurizing step.

  If the magnetic powder is surface-treated with a silane coupling material or the like in advance, there is an effect of improving the familiarity between the magnetic powder and the paint binder. In general, when an inorganic material and an organic material are mixed, this is a technique that has been conventionally employed, and is also suitable in the present invention.

The magnetic powder employed in the present invention is soft ferrite such as iron powder, magnetite ore, Mn-Zn ferrite, and further hard such as strontium ferrite powder or barium ferrite powder having a coercive force of about 2,000 to 3,000 oersted. Contains ferrite powder.
Hard ferrite powders are strontium ferrite and barium ferrite powders, which are not classified as soft magnetic powders because of their slightly higher coercive force. However, when hard ferrite magnets or permanent magnets with a surface magnetic flux density higher than that, they are magnetized. Since the magnetic circuit is configured, it is adopted in the present invention. Hard ferrite powder is suitable because it is chemically stable and does not rust.

Iron powder has the strongest magnetic adhesion to magnets compared to other magnetic powders.
Magnetite (triiron tetroxide = magnetite) is naturally produced as iron sand. Sand iron is mainly composed of magnetite, and has a characteristic that it has strong magnetic adhesion and does not rust.
Manganese zinc (Mn—Zn) ferrite powder and nickel zinc (Ni—Zn) ferrite powder are soft magnetic and do not rust.

The types of iron powder include ingot pulverized powder, atomized powder (water-atomized and gas-atomized), and reduced iron powder, which may add pulverization and classification steps.
The iron sand powder is collected as iron sand and then crushed, sorted and classified to adjust the particle size.
Soft ferrite powder can be obtained by pulverizing and classifying an inexpensive sintered body that has been collected for other uses such as a transformer to obtain the desired particle size. Several + micron diameter calcined powders are available.
As the hard ferrite powder, a commercially available powder can be obtained as a powder for a bond magnet. In addition, an inexpensive sintered body recovered for use in other applications can be demagnetized and then pulverized and classified to obtain a desired particle size.

The particle size of the magnetic powder for the front magnetic barrier layer and the back magnetic barrier layer is preferably smaller. When the particle size of the magnetic powder is small, not only is it difficult for the magnetic powder of the magnetic paint to settle or separate, but also the coating surface is smooth and convenient. Moreover, since nozzle clogging is improved, spray coating can be performed.
Spray coating is suitable for coating the front magnetic barrier layer and the back magnetic barrier layer of the present invention because a thin layer of 0.05 to 0.1 mm can be coated relatively uniformly.
The hard ferrite powder is suitable for bond magnets because its particle size is controlled on the micron order.

Conventionally, the surface of a magnetic layer containing iron powder as a magnetic component is smoothed by polishing, and a nonmagnetic surface coating is performed thereon.
In the embodiment of the present invention, instead of the non-magnetic surface coating, it is covered with a surface magnetic barrier layer containing magnetic powder that does not rust, so that rust can be prevented and a significant decrease in magnetic adhesion can be prevented. .
On the other hand, the present invention does not prevent the thin non-magnetic surface coating from being performed on the surface magnetic barrier layer on the magnetic main layer, regardless of whether the surface of the magnetic main layer is polished or not.
However, if the thickness of the nonmagnetic surface coating is increased, the magnetic adhesion force is rapidly reduced.

The average particle size of the iron powder employed in the present invention is preferably 20 to 200 microns. Iron powder of less than 20 microns is usually pulverized and classified repeatedly, resulting in a high price.
When a large average particle diameter of 200 microns or more is adopted, the roughness of the iron powder becomes rough on the surface of the coating, and the appearance is remarkably deteriorated. On the rough surface, the magnetic component becomes sparse and the decrease in the magnetic adhesion force cannot be ignored. It is not preferable. Furthermore, since the surface roughness is large, polishing becomes difficult. Further, in the state of being mixed in the paint resin binder, even if an anti-settling agent is added, the iron powder settles remarkably and the coating workability deteriorates, which is not preferable.

  If the average particle diameter of the iron powder is within the above range, the surface can be polished smoothly in order to finish the coating surface more smoothly or to increase the magnetic adhesion. In the present invention, the polished surface is covered with a surface magnetic barrier layer containing magnetic powder. Therefore, unlike the conventional simple non-magnetic material coating or laminate, as described below, the magnetic adhesion force is reduced. Can be minimized.

  The average particle diameter of the soft ferrite powder, magnetite powder, or hard ferrite powder used for the front magnetic barrier layer and the back magnetic barrier layer is preferably from several microns to 50-60 microns at most because the thickness of the layer is small.

Conventionally known is a method of depressurizing and degassing again after mixing magnetic powder or the like and a paint binder under atmospheric pressure. However, this method has a limited effect because it is difficult to remove the fine voids in the iron powder surface and the inner part thereof as seen in the reduced iron powder shown in FIG.
In the present invention, the magnetic powder is degassed and depressurized in the absence of the paint binder, and then wetted with the paint binder, and then the pressure is returned to atmospheric pressure. It is thought that it was able to be filled with the paint binder.

The larger the volume ratio of the magnetic material in the magnetic layer, the higher the magnetizing force. Therefore, the composition used for the paint binder in the present invention is the minimum required for the use of other pigments, fillers, colorants, etc., excluding the magnetic powder adopted, and for coating film formation and the necessary characteristics as a coating film. It is preferable to use a composition for ensuring the above.
On the other hand, if the volume ratio is excessively high, not only will the stability of the magnetic paint and the coating workability become a problem, but the resin component covering the surface of the iron powder will decrease, resulting in rust on the coated and dried coating film. This is not preferred because it tends to occur and the coating surface becomes rough.

In any case, the characteristics of the magnetic coating material in which the magnetic powder is dispersed differ greatly depending on the type and molecular weight of the resin component and the type of solvent. Therefore, it is a preferable aspect to add an anti-settling agent, a dispersant, a thickener and the like as required. For example, there are hydrophilic or hydrophobic silica manufactured by Nippon Aerosil Co., and BYK-425 manufactured by Big Chemie Japan Co., Ltd., which can be selected as appropriate.
The weight ratio and the volume ratio can be associated with each other by taking into consideration the ratio between the solvent and the solid component in the paint binder, the respective densities, the ratio between the paint binder and the magnetic powder, and their densities.

Next, the present invention will be described using examples and comparative examples.
The magnetic attraction force of the present invention was measured by the following method. Prepare a 30 mm * 30 mm square magnet sheet sample (1.0 mm thick, 2.5 mm pitch, multipolar magnetization, 35-40 mT surface magnetic flux density), and magnetically adsorb it to a 50 mm * 50 mm size magnetic layer The force required to separate each of them in the direction perpendicular to the plane was measured.

In addition, the test on the date of rusting was conducted every day while keeping the magnetic layer horizontal and placing a kitchen paper (50mm * 50mm) that sufficiently absorbed tap water on the surface, replenishing moisture so as not to dry. By observing the surface, the first day when the occurrence of red rust was confirmed with the naked eye was recorded.
The evaluation method described above is a severe acceleration test that is continuously brought into contact with fresh water. In this evaluation method, if the rust occurrence date is within 10 days, it is easy to rust, and if it exceeds that, it is determined that rust is difficult.

100 grams of reduced iron powder DR (DOWA IP CREATION, average particle size is 98 microns) is mixed with 45 grams of a mixture of paint binder (gardening color clear, sold by Atom Support Co., Ltd.) and anti-settling agent, A magnetic coating for the magnetic main layer for producing the magnetic main layer 1 was obtained. The average particle size referred to here is a size corresponding to the opening of the sieve through which a cumulative weight of 50% passes by the multistage classification method.
An electron micrograph of the reduced iron powder is shown in FIG. The shooting magnification is 200 times, and the 10 scales in the figure (the total length of the black lines) correspond to 500 micrometers.

  Similarly, 100 grams of iron sand powder (pulverized sand iron passed through a 280 mesh sieve, particle size of 53 microns or less) is kneaded into 75 grams of the above-mentioned mixture of paint binder and anti-settling agent, A magnetic coating material for the surface magnetic barrier layer for forming the magnetic barrier layer 4 was obtained.

Next, the magnetic coating material for the magnetic main layer was applied to the surface of the building member 2 of the wooden board in FIG. Layer 3 was obtained. The volume ratio of iron powder was 54%.
Further, the surface magnetic barrier layer 4 was formed by applying a magnetic coating for the surface magnetic barrier layer on the magnetic main layer 3 to a thickness of 0.1 mm after drying. The volume ratio of the magnetic powder was 57%.

The magnetic adhesion force due to the magnetic layer 1 was reduced by 5% when the comparative example 1 was set to 100.
Further, the date of occurrence of rust was the second day in Comparative Example 1, whereas a discoloration that seemed to be rust was visually recognized for the first time on the 20th after a delay of two weeks or more.

  In the same manner as the magnetic coating material for the front magnetic barrier layer prepared in Example 1, a magnetic coating material that serves as both the magnetic coating material for the front magnetic barrier layer and the magnetic coating material for the back magnetic barrier layer for this example was prepared by the following method. Got ready. That is, instead of the iron sand powder, 100 grams of strontium ferrite particles having an average particle diameter of 1.8 microns measured by a laser diffraction particle size analyzer were kneaded into 76.5 grams of the paint binder, and the mixture was further mixed with the paint. Passing twice through the three rolls as an apparatus, magnetic coating materials for the front magnetic barrier layer and the back magnetic barrier layer were obtained.

Next, the surface of the wooden board building member 2 in FIG. 2 was spray-coated with the magnetic coating for the back magnetic barrier layer. The thickness of the back magnetic barrier layer 5 after drying was 0.06 mm. The volume ratio of the magnetic powder was 54%.
Subsequently, on the back magnetic barrier layer 5, the same magnetic coating for the magnetic main layer as that used in Example 1 was applied in the same manner as in Example 1, but the thickness after drying was 0.37 mm. Layer 3 was formed.
Subsequently, a surface magnetic barrier layer 4 having a thickness of 0.08 mm after drying was obtained on the magnetic main layer with the magnetic coating material for the surface magnetic barrier layer.

  The magnetizing force was only 4% lower than that of Comparative Example 1, and the rusting date was 19 days.

In Example 1, the surface of the magnetic main layer 3 was first polished with sand paper of finer number 150 and then 400, and the surface magnetic barrier layer 4 was formed in the same manner as in Example 1.
The magnetizing force was 98, approaching that of Comparative Example 1, and the rusting date was 17 days.

  In preparing the magnetic coating material for the magnetic main layer and the magnetic coating material for the surface magnetic barrier layer used in Example 1, each was processed in the deaeration / decompression apparatus shown in FIG.

Specifically, a container 9 containing a predetermined amount of dried magnetic powder 8 was placed in a transparent vacuum container 7, and a funnel 10 was placed above it.
The funnel 10 is filled with a predetermined amount of a mixture 11 of paint binder and anti-settling agent (hereinafter abbreviated as “mixture 11”) and is connected to the inside of the vacuum vessel by a valve 12. The pressure inside the container 7 is reduced to at least several hundred pascals of mercury with the vacuum pump 13 and after a few minutes, the valve 12 is slowly opened while operating the vacuum pump 13, and the mixture 11 is dropped into the container 9, and the magnetic powder 8 Wet. At this time, the mixture 11 foamed and was dropped while the bubbles burst.

After the total amount of the mixture 11 was poured, the valve 12 was closed, the pump valve 14 was closed, and then the air supply valve 15 was slowly opened to return the inside of the container 3 to atmospheric pressure.
During the treatment, the solvent (water) in the mixture 11 evaporates in the vacuum vessel, but a cooling trap (not shown) is used, and the solvent corresponding to the trapped amount is returned to the atmospheric pressure after the vessel 7 is returned to atmospheric pressure. In addition to 9, the mixture was stirred. Next, the mixture was passed twice through three rolls (not shown) to promote mixing and homogenization.

Thereafter, the magnetic main layer 3 and the surface magnetic barrier layer 4 were obtained in the same manner as in Example 1.
The magnetizing force was 98, and the date of rusting increased dramatically.

(Comparative Example 1)
As shown in FIG. 3, the magnetic coating material for the magnetic main layer used in Example 1 was applied onto the building member 2 in exactly the same manner as in Example 1 except that the surface magnetic barrier layer was not provided. Layer 6 was formed.

The measured value of the magnetizing force was 0.185 Newton / square centimeter. This value was set to 100 as a reference. Since the preferable magnetizing force is 0.15 (Newton / square centimeter) or more, in the present invention, the relative value is preferably 81.1 or more, and it is judged that the magnetizing force is more than that.
The date of rust occurrence was extremely short, 2 days.
Table 1 shows the relative values of the magnetic adhesion force of Examples and Comparative Examples and the date of rust occurrence.

(Comparative Example 2)
A magnetic main layer 3 was produced in the same manner as in Example 1.
Subsequently, instead of the magnetic coating for the surface magnetic barrier layer of Example 1, 48 g of inorganic glass powder having an average particle diameter of 50 microns (density is 2.5 g / cm 3) was used in Example 1. A nonmagnetic paint mixed with 74.5 grams of a mixture of binder and anti-settling agent was prepared, and coated on the magnetic main layer and dried to form a nonmagnetic coating layer having a thickness of 0.09 mm.

The solid component of the paint binder other than the glass component of the non-magnetic paint layer was 45% by volume, which was substantially equal to the volume ratio of the solid component of the paint binder in the surface magnetic barrier layers of Examples 1 and 2.
The occurrence of rust was 29 days, but the magnetic adhesion was remarkably low at 72 because the coating layer did not contain magnetic powder.

  As apparent from Table 1, according to the present invention, it was possible to prevent iron powder from rusting while sufficiently securing the necessary magnetic adhesion.

In addition, although the formation method of the magnetic layer 1 in this invention has demonstrated by the coating method by roll coating or spray, it can implement by selecting an appropriate method without being restricted to this.
For example, brush painting or a printing method can be employed.

The magnetic layer of the present invention is a magnetic layer that is obtained by applying a magnetic paint to any paintable surface such as a pillar, door, or board, and is resistant to rust. Magnets such as holders and magnet hooks can be magnetized.
It is applied to the surface of building members and panels, and is used as a magnetic surface for posting, displaying or hanging, or as a magnetic wall for educational education for young children.

DESCRIPTION OF SYMBOLS 1 Magnetic layer 2 Building member 3 Magnetic main layer 4 Front magnetic barrier layer 5 Back magnetic barrier layer 6 Magnetic paint layer 7 Vacuum container 8 Magnetic powder 9 Container 10 Funnel 11 Mixture of paint binder and anti-settling agent 12 Valve 13 Vacuum pump 14 Vacuum pump valve 15 Ventilation valve

Claims (6)

A magnetic layer having magnetism applied to the surface of a building member such as a wall, column, door, board or partition, the magnetic powder having iron powder as a main component in the paint binder on the surface of the building member A magnetic main layer formed of a magnetic coating for a magnetic main layer mixed with a surface magnetic barrier layer in which one or more magnetic powders selected from the group of soft ferrite powder, magnetite powder, and hard ferrite powder are mixed in a coating binder magnetic layer TateSo member and use magnetic coating Table magnetic barrier layer formed by is characterized in that it is laminated. The magnetic layer of the building member according to claim 1, wherein one or more selected from the group consisting of soft ferrite powder, magnetite powder, and hard ferrite powder as a paint binder between the surface of the building member and the magnetic main layer. magnetic layer TateSo member back magnetic barrier layer, characterized in that the interposed formed by the backing magnetic barrier layer for magnetic coating material obtained by mixing a magnetic powder comprising a mixture of. 3. The method for producing a magnetic layer of a building member according to claim 1 or 2 , wherein the upper surface of the magnetic main layer is polished and then a surface magnetic barrier layer is laminated on the polished surface. A method for producing a magnetic layer of a member. The manufacturing method of the magnetic layer of the building member according to claim 1 or 2 , or the manufacturing method of the magnetic layer of the building member according to claim 3, wherein the surface magnetic barrier layer is a dried soft layer. A table through which one or more magnetic powders selected from the group consisting of ferrite powder, magnetite powder, and hard ferrite powder are first brought into contact with a paint binder in a previously degassed / depressurized container, and then the pressure is returned to atmospheric pressure. A method for producing a magnetic layer of a building member, comprising: laminating a magnetic coating for a magnetic barrier layer by drying after coating. It is a manufacturing method of the magnetic layer of the building member of Claim 2, Comprising : The said back magnetic barrier layer is 1 type or several selected from the group of the dried soft ferrite powder, magnetite ore powder, hard ferrite powder The magnetic powder is contacted with a paint binder for the first time in a container that has been degassed and decompressed in advance, and then the magnetic coating for the back magnetic barrier layer that has undergone the process of returning the pressure to atmospheric pressure is dried after coating and laminated. The manufacturing method of the magnetic layer of the building member to do. The manufacturing method of the magnetic layer of the building member according to claim 1 or 2 , or the manufacturing method of the magnetic layer of the building member according to any one of claims 3 to 5, wherein the magnetic main layer Is a magnetic main layer magnetic paint that has been subjected to the process of bringing the dried magnetic powder as a main component into contact with a paint binder for the first time in a container deaerated and decompressed in advance, and then returning the pressure to atmospheric pressure. A method for producing a magnetic layer of a building member, comprising drying after coating and laminating .