JPH0584340B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for finishing the outer surface of a building's outer wall, and more specifically, a method of using a coating composition that is waterproof and has good moisture permeability as a finishing material for the outer surface of a building's outer wall. It is related to. BACKGROUND ART Conventionally, porcelain tiles, light metals such as aluminum, metals such as colored folded plates and steel plates, various architectural paints, etc. have been used to finish the outer surfaces of building walls. However, the finishing materials for the outer surfaces of the outer walls of these buildings have a waterproof function but have almost no water vapor permeability, or materials that have neither a waterproof function nor vapor permeability. If the finishing material for the outer surface of a building's outer wall does not have a waterproof function, rainwater and the like will infiltrate the building's outer wall frame, causing problems such as water leakage, rotting of the frame material, and reduced strength. In addition, if the finishing material for the outer surface of a building's exterior wall does not have vapor permeability, the water vapor generated inside the building cannot be discharged from the exterior wall, resulting in condensation within the building frame, causing rot and rot.
This may cause problems such as the growth of mold, a decrease in strength, and a decrease in insulation performance, and if the finishing material on the outer surface is paint, it can cause blistering and peeling of the paint film itself. The present invention aims to provide the exterior wall of a building with waterproofness and water vapor permeability, which have not functioned satisfactorily with the conventional finishing methods for exterior walls of buildings as described above. 2.0m ² hmm as resistance
This method uses a coating composition with Hg/g or less on the outer surface of a building's outer wall, which eliminates various adverse effects caused by internal dew condensation of the building's outer wall frame.
This improves the durability of the coating composition itself. In order to achieve the above objects, the coating composition used in the method of finishing the outer surface of a building exterior wall according to the present invention is a thermoplastic or thermosetting resin film, or the above resin is combined with various fillers, pigments, etc. A thermoplastic or thermosetting resin that is non-water-absorbent and has good water vapor permeability. Mixed with various fillers, thermoplastic or thermosetting resin films that have low water vapor diffusion resistance and are hydrophobic by chemical methods, or have properties similar to the above resin films after coating is formed. A method of applying such a coating composition to the outer surface of a building's outer wall, in which the amount of water applied is 0.5 ml or less per 24 hours and the moisture permeability resistance is 2.0 m ² hmmHg/g or less. Examples include a partial adhesion method using adhesive or hot melt resin, a method of closely adhering a mesh or porous plate material to the outer surface of a building's outer wall, a method of painting by chipping, roller, spraying, etc., or a method using the above-mentioned coating composition. There is a method of adhering or fixing a plate-like material that is painted or laminated to the outer surface of a building's outer wall. By using the method according to the present invention as a finishing method for the outer surface of a building's outer wall, it is possible to prevent rainwater from entering from the outer surface of the building's outer wall and prevent internal dew condensation within the building frame. Generally, the water vapor pressure inside a building is higher than the outside air, and this pressure difference causes water vapor to move within the building frame from the indoor side to the outside air, but there is a large resistance to moisture permeation on the outer surface of the outer wall. If there is a material with a high moisture permeation resistance, the movement of water vapor will be hindered on the indoor side of the material, resulting in internal condensation due to condensation of water vapor, mold growth due to internal condensation, and damage to the insulation material. This results in a decrease in insulation performance, decay of the structure, and a decrease in strength. Furthermore, if the exterior wall surface finishing material with high moisture permeation resistance is a coating composition such as paint, the coating composition may blister or peel, and in cold regions, the coating may deteriorate or flake due to frost damage. By the way, by using the method for finishing the outer surface of an outer wall of a building according to the present invention, it is possible to prevent the above-mentioned problems caused by internal dew condensation and problems with the coating itself. As mentioned above, internal condensation on the exterior wall of a building occurs when the moisture permeability resistance of the outside air side material is greater than the moisture permeability resistance of the indoor side material in the joining frame materials, and the condensation flows into the interface from the indoor side. The amount of water vapor that flows out to the outside air from the interface is smaller than the amount of water vapor that flows out to the outside air from the interface. Therefore, if the amount of water vapor transferred throughout the entire structure is large, the water vapor is condensed at the interface, so the finish of the outer surface of the building's outer wall is The moisture permeation resistance of the coating composition used must be lower than the moisture permeation resistance of the underlying material, that is, the material that will become the exterior wall surface material before the coating composition is applied to the outer surface of the building's exterior wall. Table 1 shows the moisture permeability resistance value of the base material that can be used for the finishing method of the exterior wall of a building based on the present invention, and the moisture permeable resistance value of the material used in the finishing method based on the present invention is 2.0 m. ² hmmHg/g
Must be less than or equal to Note that this moisture permeation resistance value is also proven by Examples described later.

[Table] Water permeability shall be 0.5ml or less using a test method based on JIS A 6910. Originally, the water permeability should be 0 ml, but the coating composition used in accordance with the present invention has good water vapor permeability, and even if some rainwater enters the interior, it will not turn into water vapor again. Since it is discharged, the water permeability does not need to be 0 ml.
However, if the amount of water permeation exceeds 0.5ml, the intruding water moves inside the structure and accumulates, so it cannot be said that the structure is waterproof. Therefore, the coating composition used for finishing the outer surface of a building exterior wall according to the present invention is as follows:
Water permeability is less than 0.5ml per 24 hours, moisture permeability resistance is 2.0
Must be less than m ² mmHg/g. Next, comparative experimental methods and results conducted based on the present invention will be shown as examples. <Comparative experiment method> Rooms A and B where temperature and humidity can be adjusted as shown in Figure 1
A specimen 5 created by the test specimen creation method described below was installed on the boundary wall of a constant temperature and humidity chamber, and the temperature and humidity of rooms A and B were changed and the wind speed on the surface of the specimen was adjusted using a fan 6. , the moisture content distribution and temperature distribution of the specimen were measured. In addition, the measurement of water permeability is based on JIS A
The moisture permeability resistance is measured using the water permeability funnel test according to 6910 according to ASTM-E96 moisture permeability test method for sheet materials. The test film compositions and their physical properties are shown in Table 2.A
Table 3 shows the setting conditions for the room and B room.

【table】

[Table] ○ Sample preparation method As shown in Figure 2, a sample with a thickness of 5 mm with good surface accuracy.
A mortar plate 1 of width 300 mm and height 300 mm was prepared,
10 of them are stacked one on top of the other, a polystyrene foam 2 of the same size as the mortar board is superimposed on one side, and the periphery is adhesive-sealed with aluminum tape 3 with a thickness of 200 μm. At this time, between mortar and mortar,
A T-type thermocouple is embedded in the contact interface between the polystyrene foams so that there are no gaps. Mortar side surface 4 of the base fabricated as above
The test materials (a) are acrylic rubber-based elastic paint, (b) is a sand wall-like spray material, and the test materials (c) are polyethylene sheets and (d) Gore-Tex (fabric manufactured by Gore, Inc. in the United States).
were dot-bonded to obtain specimen 5. ○ Results of comparative experiments As shown in Figure 1, each specimen was installed on the boundary wall between Room A and Room B with the test material facing Room B, and the temperature and humidity were adjusted as shown in Table 3. 24 hours after reaching a steady state, remove the specimen, peel off the aluminum tape 3, measure the weight of the mortar plate, and calculate the weight before the test starts. The weight moisture content was measured by comparing with the absolute dry weight. The coating and film surface conditions were also observed. The moisture content, temperature distribution, etc. under each condition are shown in FIGS. 3 and 4.
Numbers a to d in the figure each indicate the material number in Table 2, and although the temperature distribution during steady state shows almost the same change, the moisture content obviously differs depending on the moisture permeation resistance of the material. Sand wall spray material b and Gore-Tex d with moisture permeability resistance of 2.0 m ² hmmHg/g or less
In this case, whether the temperature of room B is 0°C or 5°C, the moisture content on the side of room A (high temperature side) is high, but the moisture content on the side of room B is low, and water vapor from room A side is discharged to room B side. It shows that Through the above experiments, the moisture permeability resistance was 2.0m ² hmmHg/
It has been found that if a coating composition with a water permeability of 0.5 ml or less is applied to the outer surface of a building's outer wall, harmful effects such as internal dew condensation can be prevented.

[Brief explanation of drawings]

Figure 1 is a sectional view of the main parts of an experimental apparatus for testing the superiority of the finishing method for the outer surface of a building exterior wall based on the present invention, and Figure 2 is a perspective view of a specimen used in the experiment. 3 and 4 are graphs showing the experimental results of moisture content and temperature for each distance from the interface of chambers A and B. DESCRIPTION OF SYMBOLS 1... Mortar plate, 2... Polystyrene foam, 3... Aluminum tape, 4... Mortar plate surface, 5... Specimen, 6... Fan.

Claims (1)

[Claims] 1 Reinforced concrete construction, steel frame concrete construction,
Reinforced steel concrete construction, PC board construction, ALC board construction,
As an external surface finishing method for external walls of buildings such as asbestos-cement board construction, wooden construction, block construction, and inorganic siding board construction, water permeation rate is 0.5 ml or less per 24 hours,
If the coating composition has a moisture permeability resistance of 2.0 m ² hmmHg/g or less, it can be applied to a resin film or a resin film containing fillers, pigments, etc. by partial adhesion or through a mesh-like porous plate material. A method for finishing the outer surface of an exterior wall of a building, which method comprises applying the film or coating using a brush, roller, spraying, etc., or adhering or fixing the plate-shaped material coated with the film or coating.