JP2001302370A - Method for manufacturing cement-base ceramic material and cement-base ceramic material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cement-base ceramic material having a film which is substantially free of pinholes and is homogeneous. SOLUTION: A jacket material 1 which is the cement-base ceramic material has a base material 3 and a film 5 formed on the surface of this base material 3. The film 5 covers the front side surface, rear side surface and flanks of the base material 3. The jacket material 1 is obtained by first exposing the base material 3 to high-temperature steam generated by induction heating to heat up the base material (a preheating process step). A powder resin is then adhered to the front surface of the base material 3 by electrostatic coating (a adhering process step). Next, the film 5 is formed by heating and melting the powder resin (a film forming process step). The non-hygroscopicity and non-water absorption properties of the jacket material 1 are improved by the film 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to an exterior material for a building,
The present invention relates to a cement-based ceramic material such as an interior material and a tile (so-called western tile), and particularly to a method of forming a film on the cement-based ceramic material.

[0002]

2. Description of the Related Art For example, cement-based ceramic materials (also referred to as ceramic cement) are often used as exterior materials (outer wall materials) for houses. This cement-based ceramic material includes a base material obtained by heating and curing a cement composition including an aggregate and the like, and a film formed on one surface (front surface or back surface) of the base material. Usually, a film is formed by applying a paint to a substrate by a method such as roll coating or spray coating, and drying and curing the paint. As the paint, a solvent-based or water-dispersed paint is used. This coating enhances the design of the exterior material and also improves the moisture permeability.

[0003] In a house in a cold region, a coating is provided on both sides and four sides of the exterior material, as well as on one side. Thereby, the non-water-absorbing property of the exterior material is improved, and it is suppressed that the absorbed water freezes and expands in winter and cracks are generated in the exterior material.

[0004]

However, in this case, fine holes (pinholes) may be generated in the film due to the solvent or water volatilized during the drying and curing steps. When a pinhole is generated, moisture penetrates into the exterior material through the pinhole, so that there is a problem that the moisture permeability and the non-water absorption of the exterior material are reduced. Repeated coating prevents the penetration of moisture from the pinhole to some extent, but repeated coating and drying increases the manufacturing cost of the exterior material and increases the film thickness. And uneconomical.

[0005] The surface of the exterior material is porous and has irregularities because it is a cement-based ceramic material. However, it is difficult to coat the surface in an airtight state with ordinary paint, and the coating becomes uneven. Would. For this reason, the moisture-permeable and non-water-absorbing properties of the exterior material also become insufficient.

[0006] Further, since the pH of the surface of the exterior material greatly varies depending on the lot and the site, depending on the type of paint used, the adhesion between the substrate and the film becomes insufficient or the film thickness becomes uneven. Sometimes. These factors also result in insufficient moisture permeability and non-water absorption of the exterior material.

[0007] Similar problems occur not only in exterior materials but also in general cement-based ceramic materials such as interior materials and western tiles.

The present invention has been made in view of such a problem, and an object of the present invention is to provide a cement-based ceramic material having almost no pinholes and having a uniform film.

[0009]

Means for Solving the Problems The invention made to achieve the above object is a method for producing a cement-based ceramic material comprising a substrate and a film formed on the substrate, comprising: A method for producing a cement-based ceramic material, comprising: an attaching step of attaching a powder resin to a surface of the material; and a film forming step of forming a film by heating and melting the attached powder resin.
It is.

Another object of the present invention is to provide a cement-based ceramic material comprising a substrate and a film formed on the substrate, wherein the film comprises a substrate. A cement-based ceramic material characterized by being formed by heating and melting a powder resin adhered thereon.

In these inventions, a film is formed by heating and melting the powder resin adhered to the substrate. Therefore, pinholes due to evaporation of the solvent and water do not occur, and the non-moisture permeability and non-water absorption of the cement-based ceramic material are improved. Also, since the powder resin adheres uniformly to the substrate surface, the coating becomes uniform even if the substrate surface is porous,
Non-moisture permeability and non-water absorption are not easily impaired. Further, since the adhesion of the resin powder is hardly affected by the pH of the substrate surface, a uniform film can be formed. Further, by controlling the amount of powder resin adhered, a film having a desired film thickness can be obtained, so that there is no need to apply a paint again, and since there is no need to volatilize the solvent or water, the manufacturing process is simplified.

Preferably, the application of the powder resin in the application step is achieved by electrostatic painting. Adhesion of the powder resin becomes uniform by adopting the electrostatic coating. Also,
In the electrostatic coating, the powder resin can be attached to the front surface, the back surface, and the side surface of the cement-based ceramic material in one step, so that the manufacturing process is further simplified.

Preferably, in the film forming step, the powder resin is heated and melted by dielectric heating. Dielectric heating is a heating method that utilizes heat generated by electromagnetic induction, and is a high-energy process. The powdered resin is exposed to a relatively high temperature (for example, 200 ° C. or higher) by dielectric heating, and its melting is achieved in a short time. Since the powdered resin does not contain a solvent or water, even when it is exposed to a high temperature, no bubbles are generated due to volatilization of these.

Preferably, the manufacturing method further includes a preheating step. In the preheating step, the substrate before the powder resin is attached is exposed to high-temperature steam generated by dielectric heating. As a result, even if the substrate has a large thickness, the temperature is raised in a short time. Further, the surface of the base material is cleaned by the steam.

The cement-based ceramic material thus obtained is suitable for an exterior material, an interior material, and a western tile of a building that is required to be non-permeable or non-water-absorbing.

[0016]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.
Embodiments of the present invention will be described.

FIG. 1 is a sectional view showing an exterior material 1 as a cement-based ceramic material according to an embodiment of the present invention. The exterior material 1 includes a substrate 3 and a film 5 formed on the surface of the substrate 3. The coating 5 covers the front surface, the back surface, and the side surface of the substrate 3. Thereby, the base material 3
Is prevented, and cracks due to freezing are prevented. Of course, in a region where there is no possibility of freezing, for example, only the front surface or only the back surface of the base material 3 may be covered with the coating 5. Even if only the front side or the back side is covered,
Is impermeable to moisture.

The substrate 3 is formed by heating and hardening a cement composition containing an aggregate and the like. Base material 3
May be blended with an inorganic foam for the purpose of weight reduction.
So-called ALC (lightweight foamed concrete) is also suitable as the base material 3. The thickness of the substrate 3 is not particularly limited, and is appropriately determined according to the application.

The film 5 is formed from a resin composition. The synthetic resin used for the film 5 may be a thermosetting resin or a thermoplastic resin. Further, a thermosetting resin and a thermoplastic resin may be mixed and used at a mass ratio of about 5/5 to 9/1. Specific examples of the synthetic resin preferably used include an epoxy resin, a polyester,
Examples include polyethylene, polypropylene, polyamide, and acrylic resin. Additives such as an ultraviolet absorber, a deterioration inhibitor, and a filler are appropriately added to the resin composition as needed. Further, the design of the exterior material 1 may be enhanced by blending a coloring agent such as a pigment.

The thickness of the film 5 is preferably from 10 μm to 300 μm, particularly preferably from 25 μm to 100 μm. When the film thickness is less than the above range, the moisture impermeability of the exterior material 1 may be insufficient. Conversely, if the film thickness exceeds the above range, the effect of preventing moisture permeation may plateau for the film thickness and become uneconomical, and the film 5 may warp the substrate 3. Sometimes.

In the case 1, only the coating 5 is provided on the base material 3. However, between the base material 3 and the coating 5,
On top of this, another layer such as a colored layer may be provided. The design of the exterior material 1 is improved by the colored layer.

FIG. 2 is a flowchart showing an example of a method for manufacturing the exterior material 1 of FIG. This manufacturing method includes a preheating step using high-temperature steam, an adhesion step using electrostatic coating,
A film forming step by dielectric heating.

In the preheating step, high-temperature steam is injected onto the substrate 3. The temperature of steam is above 200 ° C, especially 25
0 ° C. or higher is preferred. The base material 3 is heated in a short time by being exposed to the high-temperature steam. In addition, since the surface of the base material 3 is cleaned and the foreign matter is removed by spraying the high-temperature steam, the film formation inhibition by the foreign matter is also prevented.
Such high-temperature steam is obtained by a dielectric heating device (the details of the dielectric heating device will be described later in the description of the film forming process). By using water vapor of 200 ° C. or higher obtained by dielectric heating, the substrate 3
This prevents a water droplet from adhering to the surface of the substrate and prevents the adhesion of the powder resin from being hindered by the water droplet in a subsequent adhesion step.

The substrate 3 is preferably heated to a temperature higher than the softening point of the powder resin used in the subsequent attachment step. As a result, the powder resin adhered to the surface of the substrate 3 is partially melted (at the contact portion), and is temporarily fixed to the substrate 3. Therefore, detachment of the powder resin from the base material 3 is suppressed.

When it is not necessary to raise the temperature of the substrate 3, the preheating step may be omitted. In addition, the preheating step may be achieved by, for example, burner heating, boiler heating, far-infrared heating, electric heater heating, or the like instead of heating with high-temperature steam. Further, heating with a burner, a boiler, far-infrared rays, an electric heater, or the like and cleaning with high-temperature steam may be used in combination.

In the attaching step, a positively charged powder resin (this powder resin is made of a resin composition to which additives and the like are added) is sprayed on the base material 3. Since the base material 3 is grounded and the base material 3 contains a small amount of water, the powder resin is attracted to the base material 3 having a low potential by electrostatic attraction and adheres to the surface of the base material 3. At this time, the powder resin wraps around to the side opposite to the spray nozzle, so that the powder resin adheres to the front surface, the back surface, and the side surface of the substrate 3 at the same time. For example, when the film 5 is formed only on the front side,
The back side and the side may be masked. Since the powdered resin does not contain a solvent, there is no danger of ignition and the working environment is good.

The average particle diameter of the powder resin is 5 μm or more and 40
μm or less, preferably 10 μm or more and 30 μm or less. If the average particle diameter is less than the above range, the workability in the attaching step may be reduced. Conversely, if the average particle diameter exceeds the above range, the film thickness of the film 5 may become uneven.

When a synthetic resin having a dielectric constant of zero (eg, polyethylene or polypropylene) is used, a conductive powder is blended with the synthetic resin. This facilitates charging of the powder resin. Of course, a conductive powder may be further blended with the synthetic resin having dielectric properties. The compounding amount of the conductive powder is 0.5 to 100 parts of the synthetic resin.
To about 10 parts (based on mass). The average particle diameter of the conductive powder needs to be sufficiently smaller than the average particle diameter of the powder resin.

As the electrostatic coating machine, any of a corona discharge coating machine and a triboelectric coating machine can be used. Further, instead of the electrostatic coating, the powder resin may be attached to the base material 3 by, for example, a sieving method. However, electrostatic coating is preferred because the powder resin easily adheres uniformly.

In the film forming step, the base material 3 to which the powder resin is attached
Is heated. The powder resin is melted by heating, and the film 5
Is formed. Since the powder resin does not contain a solvent or water, pinholes do not occur due to their volatilization.
In addition, since the powder resin does not cause dripping as seen in ordinary paints, a uniform film 5 can be formed even on a substrate 3 having a porous surface. Therefore, the exterior material 1 excellent in moisture permeability and non-water absorption can be obtained. Further, by using the powdered resin, drying for a long time as in the case of ordinary paint is unnecessary, and the manufacturing process of the exterior material 1 is simplified.

As a suitable heating means in the film forming step, dielectric heating can be mentioned. FIG. 3 is a schematic sectional view showing the dielectric heating device 7. The dielectric heating device 7 includes a casing 9, and a heat insulating material 11 is attached to an inner wall of the casing 9. An annular coil 13 is provided inside the casing 9. Inside the coil 13, a substrate 3 having a surface coated with a powder resin is suspended by a suspension member 15. Heating plates 17 made of metal (for example, steel or stainless steel) are provided on both left and right sides of the base material 3. The substrate 3 is moved together with the hanging member 15 by a moving means (not shown) as shown in FIG.
In the direction perpendicular to the plane of the drawing. When a current (for example, a low-frequency current) is applied to the coil 13, the heating plate 17 is induced by electromagnetic induction.
Generates heat, and the radiant heat heats the base material 3 to melt the powder resin.

The heating temperature is adjusted by controlling the voltage. Preferably, the temperature of the heating plate 17 is from 250 ° C. to 2 ° C.
A current of about 80 ° C. is passed through the coil 13. By heating at such a high temperature, the powder resin melts in a short time. Since the powdered resin does not contain a solvent or water, even if it is rapidly heated, the generation of air bubbles due to volatilization thereof does not occur.

Instead of dielectric heating, the powder resin may be melted by burner heating, boiler heating, far infrared heating, electric heater heating, or the like. However, dielectric heating is preferred for reasons such as easy temperature control, short heating time, and no risk of ignition of the powder resin.

If the dielectric heating apparatus in the preheating step, the electrostatic coating machine in the adhesion step, and the dielectric heating apparatus 7 in the film forming step are arranged in tandem and connected by rails or the like, the base material 3 is formed from the preheating step. Since it is transported in one line to the membrane process,
The manufacturing equipment for the exterior material 1 becomes compact. In addition, since a similar dielectric heating device is used in the preheating step and the film forming step, a common control mechanism such as an inverter can be used. This also makes the manufacturing facility for the exterior material 1 compact.

[0035]

EXAMPLES Hereinafter, the effects of the present invention will be clarified by examples, but it is needless to say that the present invention should not be construed as being limited based on the description of the examples.

[Example] A substrate composed of cement, sand and inorganic fine particles was prepared. The substrate was heated with steam at about 220 ° C. generated by dielectric heating. next,
Powder resin was attached to the front surface of the substrate by electrostatic coating. Acrylic resin was used as the resin. This powdered resin was heated and melted by a dielectric heating method to form a film, and a packaging material of the example was obtained. The heating temperature was about 250 ° C. The thickness of this film was about 25 μm.

[Comparative Example] A coating material containing an acrylic resin as a main component was applied to the surface of the same base material as in the example using a roll coater. This was dried to form a film, and a packaging material of a comparative example was obtained. The thickness of the film was about 60 μm.

[Water Absorption Test] The exterior materials of Examples and Comparative Examples were cured at room temperature for 2 days. Then, a foot-length funnel having an inner diameter of 70 mm was adhered to each front side surface, and water was injected until the height became 20 cm. Then, after 24 hours, the water absorption was measured. The exterior material of the example had a water absorption of 0.1 ml, whereas the exterior material of the comparative example had a water absorption of 3.1 ml at room temperature. From the experimental results, the superiority of the present invention was confirmed.

Although the manufacturing method of the present invention has been described above using an exterior material as an example, this manufacturing method is not limited to the production of not only exterior materials but also various cement-based ceramic materials such as interior materials and western tiles. It is suitable for. For example, when the present invention is applied to a Western tile, the whitening phenomenon of the Western tile due to water absorption is also prevented.

[0040]

As described above, according to the production method of the present invention, a cement-based ceramic material having almost no pinholes and having a uniform film can be obtained. This cement-based ceramic material is excellent in non-moisture permeability and non-water absorption.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an exterior material as a cement-based ceramic material according to an embodiment of the present invention.

FIG. 2 is a flowchart illustrating an example of a method of manufacturing the exterior material of FIG. 1;

FIG. 3 is a schematic sectional view showing a dielectric heating device used in a film forming process.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Exterior material 3 ... Substrate 5 ... Film 7 ... Dielectric heating device 9 ... Casing 11 ... Heat insulation material 13 ... Coil 15 ... Hanging member 17 ...・ Heat plate

Continued on the front page (72) Inventor Kazuo Aoyama 2-28 Naracho, Ibaraki-shi, Osaka (72) Inventor Norio Yamagishi 2-57 Imai, Higashiosaka-shi, Osaka F-term (reference) 4D075 AA09 BB35Z DB12 DC02 EA02 4G028 CA01 CB02 CB04 CB06 CC03 CD01 CD02

Claims (6)

[Claims] 1. A method for producing a cement-based ceramic material comprising a substrate and a film formed on the substrate, comprising: an attaching step of attaching a powder resin to a surface of the substrate; A process for forming a film by heating and melting a resin. 2. The production method according to claim 1, wherein the adhesion of the powder resin in the adhesion step is achieved by electrostatic coating. 3. The method according to claim 1, wherein the heating in the film forming step is dielectric heating. 4. The method according to claim 1, further comprising a preliminary heating step of exposing the substrate before the powder resin is attached to high-temperature steam generated by dielectric heating to raise the temperature of the substrate. The production method according to the paragraph. 5. A cement-based ceramic material comprising a substrate and a film formed on the substrate, wherein the film is formed by heating and melting a powder resin adhered on the substrate. A ceramic ceramic material characterized by being made. 6. The cement-based ceramic material according to claim 5, which is used as an exterior material, an interior material or a tile of a building.