Method for creating a barrier in the soil under the floor

Abstract

To prevent defects in the resin coating that acts as a barrier to the soil under the floor. [Solution] The method for forming a barrier 8 on the underfloor soil 5 comprises the steps of: laying granular zeolite 6a (moisture absorbent) on the underfloor soil 5 to form a dehumidifying layer 6; and spraying a mixture of an aqueous synthetic resin emulsion, an insecticide, and a hardening agent onto the upper surface of the dehumidifying layer 6 and hardening it to form a resin film 7 covering the dehumidifying layer 6. The synthetic resin emulsion is an emulsion of vinyl acetate-acrylic acid ester copolymer. The hardening agent contains a urethane prepolymer and an isocyanate, which react with the water in the synthetic resin emulsion to produce polyurethane.

Description

Technical Field

[0001] The present invention relates to a method for forming a barrier on the underfloor ground to protect wood in the underfloor space of a building.

Background Art

[0002] The underfloor area of a wooden building is humid, which is an environment suitable for the propagation and growth of fungi such as wood-rotting fungi and insects such as termites, and it is required to protect the wood from these fungi and insects. In Patent Document 1, a base agent obtained by mixing a chemical into an aqueous synthetic resin emulsion and a curing agent are mixed immediately before being sprayed by a spray gun, and the mixed solution is sprayed onto the soil under the floor. Since the mixed solution starts to cure immediately after spraying, a resin film covering the soil surface is formed. This resin film functions as a barrier that blocks the evaporation of moisture from the soil and the intrusion of termites and the like, so that the underfloor space can be prevented from reaching a humidity suitable for the propagation of fungi and insects. Furthermore, the effect of the chemical agent in the resin film can suppress the propagation of fungi and insects.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Disclosure of the Invention

Problem to be Solved by the Invention

[0004] However, several months after the formation of the resin film covering the entire surface of the underfloor soil, defects such as cracks, holes, and curling of edges adjacent to the foundation and the like may occur. As a result of research by the present inventor on the causes of defects such as holes, cracks, and curling of the resin film, it was found that in the long-term and slow curing process of the resin film, the moisture in the resin film evaporates and the resin shrinks.

Means for Solving the Problem

[0005] The present invention was made to solve the above problems, and is characterized by comprising the steps of forming a barrier over subfloor soil by laying granular moisture-absorbing material on subfloor soil to form a dehumidifying layer, and forming a resin coating over the dehumidifying layer by spraying a mixed solution of an aqueous synthetic resin emulsion, a chemical agent, and a hardening agent onto the upper surface of the dehumidifying layer and hardening it. According to this method, the dehumidifying layer absorbs moisture from the resin coating during its initial curing stage, thus suppressing the evaporation of moisture from the resin coating during its slow curing process and preventing defects in the resin coating. Furthermore, the surface of the dehumidifying layer, formed from granular moisture absorbent material, has irregularities, and the resin coating is formed to conform to these irregularities, thus stably holding the resin coating in place.

[0006] Zeolite is preferable as an easily available granular moisture absorbent.

[0007] Preferably, the average particle size of the granular moisture absorbent is 3 to 9 mm, the average thickness of the dehumidifying layer is 15 to 25 mm, and the average thickness of the resin coating is 3 to 10 mm. If the average particle size of the moisture absorbent is less than 3 mm, its function as an aggregate to hold the resin coating will be reduced, and if it exceeds 9 mm, its dehumidifying function will be reduced. If the average thickness of the dehumidifying layer is less than 15 mm, its dehumidifying function will be reduced, and if it exceeds 25 mm, its ability to hold the resin coating will be reduced. If the average thickness of the resin coating is less than 3 mm, its barrier function will be unstable, and if it exceeds 10 mm, there is a possibility that peeling or other damage may occur to the resin coating.

[0008] In one embodiment, the curing agent comprises a urethane prepolymer and an isocyanate, which react with the water in the synthetic resin emulsion to produce polyurethane, and the resin film comprises the synthetic resin contained in the synthetic resin emulsion and polyurethane. The synthetic resin in the aforementioned synthetic resin emulsion is a vinyl acetate-acrylic acid ester copolymer. [Effects of the Invention]

[0009] According to the present invention, by forming a dehumidifying layer made of granular moisture-absorbing material in the soil under the floor and forming a resin coating on this dehumidifying layer, it is possible to avoid defects in the resin coating. Furthermore, the strength of the resin coating can be increased. [Brief explanation of the drawing]

[0010] [Figure 1A] This is a schematic cross-sectional view showing the step of forming a dehumidifying layer by laying granular zeolite on the soil under the floor in the barrier formation method of the present invention. [Figure 1B] This is a schematic cross-sectional view showing the step of forming a resin film on a dehumidifying layer in the barrier formation method of the present invention. [Figure 2] This is a cross-sectional view showing an enlarged view of the main part of Figure 1B. [Figure 3] This is a schematic diagram showing the spraying system used in the barrier formation method of the present invention, with a magnified view of the spray gun. [Modes for carrying out the invention]

[0011] The following describes a method for forming a barrier in the soil under the floor according to one embodiment of the present invention, with reference to the drawings. Figure 1A shows a part of the underfloor structure to which the barrier formation method is applied. Under the floor, for example, a concrete foundation 1 and a pier 2 are arranged. Wooden floor joists 3 are placed on the pier 2, and the floor 4 is supported by these foundation 1 and floor joists 3.

[0012] <Summary of the present invention method> First, the outline of the present invention will be explained. As shown in Figure 1A, a dehumidifying layer 6 is formed over the entire upper surface of the underfloor ground 5, and then, as shown in Figure 1B, a resin coating 7 is formed to cover the entire dehumidifying layer 6, thereby completing the barrier 8.

[0013] <Dispersion System> FIG. 3 shows a spraying system 9 for forming the resin coating 7. The spraying system 9 includes a spray gun 10 (sprayer). The spray gun 10 is provided with a body 11, a handle 12 fixed to the body 11, a trigger 13 connected to the body 11, a shaft 14 extending from the tip of the body 11, a tip nozzle 16 connected to the tip of the shaft 14 via a connector 15, a valve 17 connected to the connector 15, and a lever 18 for operating the opening and closing of the valve 17.

[0014] A valve 12a is attached to the lower end of the handle 12, and as will be described later, the base material entering this valve 12a reaches the mixing chamber in the connector 15 through the passage in the handle 12, the passage in the body 11, and the passage in the shaft 14. The valve 17 is provided with a nipple 17a, and as will be described later, the curing agent entering this nipple 17a reaches the mixing chamber of the connector 15 through the valve 17. The base material and the curing agent mixed in the mixing chamber of the connector 15 are sprayed through the nozzle 16. A valve (not shown) is incorporated in the body 11, and the supply of the base material is controlled by opening and closing this valve through the operation of the trigger 13. In addition, the supply of the curing agent is controlled by opening and closing the valve 17 through the operation of the lever 18.

[0015] The spraying system further has a first container 20 and a pressure feeding device 22 that pressure-feeds the base material contained in the first container 20 to the valve 12a of the spray gun 10 via a tube 21, and also has a second container 30 and a pressure feeding device 32 that pressure-feeds the curing agent contained in the second container 30 to the nipple 17a of the spray gun 10 via a tube 31.

[0016] Next, the method for forming the barrier 8 will be described in detail. <Ground leveling step> First, foreign matter on the upper surface of the soil 5 is removed, and the soil 5 is leveled to eliminate large irregularities. <Chemical spraying step> The chemical is sprayed onto the wood exposed in the underfloor space using a spray gun. <Dehumidifying layer forming step> Next, a granular zeolite 6a (porous aggregate; moisture absorbent) composed of crushed pieces of natural mineral as schematically shown in Figure 2 is laid over the entire upper surface of the exposed soil 5 under the floor to form a dehumidification layer 6.

[0017] <Resin Film Forming Step> Next, the resin film 7 is formed using the spraying system 9 shown in Figure 3. Specifically, a chemical agent containing an aqueous synthetic resin emulsion and an insecticidal component is placed in the first container 20 and stirred. A curing agent is contained in the second container 30.

[0018] The main agent in the first container 20 is pressure-fed toward the spray gun 10 by driving the pressure feeder 22, and the curing agent in the second container 30 is pressure-fed toward the spray gun 10 by driving the pressure feeder 32. By operating the trigger 13 to open the valve in the body 11 and operating the lever 18 to open the valve 17, the chemical agent-containing main agent and the curing agent converge at the connector 15, are mixed in the mixing chamber, and the resulting mixed liquid is sprayed in a mist form from the tip of the nozzle 16 onto the dehumidification layer 6.

[0019] Initial curing starts immediately after spraying of the mixed liquid, and the mixed liquid loses fluidity in a short time (several minutes) after being sprayed onto the dehumidification layer 6. Therefore, although part of the mixed liquid penetrates between the granular zeolites 6a, most of it remains on the dehumidification layer 6 to cover the dehumidification layer 6 and form the resin film 7. Note that, as shown in Figure 1B, the mixed liquid may also be sprayed on the side surfaces of the foundation 1 and the pier stones 2 to form the resin film 7 on these surfaces as well.

[0020] The resin film 7 blocks moisture evaporating from the soil 5 to prevent the under-floor space from becoming highly humid, and avoids the under-floor space becoming a humidity environment where termites and wood rot fungi grow. In addition, the resin film 7 prevents wood rot fungi and termites from the soil 5 from intruding. Furthermore, the chemical agent contained in the resin film 7 exerts an insecticidal effect. As a result, the wood in the under-floor space can be prevented from being damaged by termites and wood rot fungi.

[0021] In the resin coating 7, slow hardening continues for one to several months after application. During this hardening process, if the moisture in the resin coating 7 evaporates, cracks or holes may form in the resin coating 7, or peeling may occur at the edges adjacent to the foundation 1 or pier stone 2. However, in this embodiment, the moisture in the resin coating 7 is absorbed by the dehumidifying layer 6 during the short initial hardening process (several minutes) after application, thus avoiding such problems. Furthermore, the resin coating 7 is soft for a short time after application, and some of it penetrates between the granular zeolite 6a, and it conforms to the unevenness of the granular zeolite 6a on the upper surface of the dehumidifying layer 6, so it is stably supported by the dehumidifying layer 6. In other words, the granular zeolite 6a plays the role of aggregate that holds the resin coating 7.

[0022] The average particle size of the granular zeolite 6a is preferably 3 to 9 mm, more preferably 5 to 8 mm. If it is less than 3 mm, its function as an aggregate for holding the resin coating 6 is reduced, and if it is greater than 9 mm, the dehumidifying effect decreases. The average thickness of the dehumidifying layer 6 is preferably 15 to 25 mm. If it is less than 15 mm, the dehumidifying effect is reduced, and if it is greater than 25 mm, the retention effect of the resin coating 6 is weakened. The average thickness of the resin coating 7 is preferably 3 to 10 mm. Below 3 mm, the barrier effect is unstable, and above 10 mm, peeling or other issues may occur.

[0023] The synthetic resin emulsion of this embodiment contains a vinyl acetate-acrylic acid ester copolymer. The curing agent contains a urethane prepolymer and a reactive free isocyanate. The curing agent reacts (cures) with the water in the main component to form a three-dimensional network of polyurethane. The resin coating 7 contains the synthetic resin and polyurethane, which are components of the synthetic resin emulsion.

[0024] <Example of experiment> The following describes an example of an experiment. Granular zeolite 6a with an average particle size of approximately 7 mm is laid on the upper surface of the subfloor soil 5 to an average thickness of 20 mm to form a dehumidifying layer 6.

[0025] 18 kg of the synthetic resin emulsion concentrate is added to the first container 20. This synthetic resin emulsion concentrate contains 23-27 w% vinyl acetate / acrylic acid ester copolymer and 70-74 w% water. This synthetic resin emulsion concentrate is diluted with 18 liters of water. Furthermore, 0.2 kg of the chemical agent is added to the first container 20 and stirred. The chemical agent contains termite and fungicide components. Examples include Takelock (registered trademark: Osaka Gas Chemical Co., Ltd.), which contains clothianidin; Stealth SC (registered trademark: BASF Japan Ltd.), which contains chlorfenapyr; and Hachikusan FL (registered trademark: Bayer CropScience Co., Ltd.), which contains imidacloprid.

[0026] The hardener for product name "H6G09" contains approximately 50 wt% urethane prepolymer, 1-5 wt% tolylene diisocyanate, and approximately 48 wt% plasticizer. The hardener should be mixed with the main component at a ratio of 10-20 wt% using a spray gun 10.

[0027] As mentioned above, when the main agent and hardener are mixed and sprayed using the spray gun 10, hardening begins immediately after spraying, and the initial hardening is completed in 4 to 5 minutes. During this initial hardening, the resin coating 7 is elastic, but after one month it has hardened to the point where it does not deform when a person stands on it. Even after six months, the resin coating 7 remains firmly hardened, and no defects such as holes, cracks, or peeling were observed.

[0028] The present invention is not limited to the above embodiments and various other forms are possible. Porous aggregates other than zeolite may be used as granular moisture absorbents. For example, aggregates made from calcined volcanic ash may be used. The synthetic resin used in the synthetic resin emulsion may be a synthetic resin other than vinyl acetate-acrylic acid ester copolymer. [Industrial applicability]

[0029] This invention can be applied to a method for forming an insect-repellent barrier in the soil under a floor. [Explanation of Symbols]

[0030] 5. Soil under the floor 6 Dehumidification layer 6a Granular zeolite (granular moisture absorbent) 7. Resin coating 8 Barrier

Claims

1. The process involves laying granular moisture-absorbing material on the soil under the floor to form a dehumidifying layer, The process involves spraying a mixture of an aqueous synthetic resin emulsion, a chemical agent, and a hardening agent onto the upper surface of the dehumidifying layer and curing it to form a resin coating that covers the dehumidifying layer. A method for forming a barrier to the soil under the floor, characterized by comprising the following features.

2. The method for forming a barrier to the soil under the floor according to claim 1, characterized in that the granular moisture-absorbing material is zeolite.

3. The method for forming a barrier on subfloor soil according to claim 1, characterized in that the average particle size of the granular moisture-absorbing material is 3 to 9 mm, the average thickness of the dehumidifying layer is 15 to 25 mm, and the average thickness of the resin coating is 3 to 10 mm.

4. The curing agent comprises a urethane prepolymer and an isocyanate, and reacts with the water in the synthetic resin emulsion to produce polyurethane. The method for forming a barrier on subfloor soil according to claim 1, characterized in that the resin coating contains the synthetic resin contained in the synthetic resin emulsion and polyurethane.

5. The method for forming a barrier on subfloor soil according to claim 4, characterized in that the synthetic resin in the synthetic resin emulsion is a vinyl acetate / acrylic acid ester copolymer.

Images