Method for blocking noxious gas generated from concrete

Description: TECHNICAL FIELD [Detailed description of the invention]

【0001】

[Technical field to which the invention belongs]

The present invention relates to a method for blocking harmful gas originating from concrete.

【0002】

[Conventional technology]

In a concrete building, various measures have been taken to improve its function. For example, a polyurethane foam layer is provided on the inner surface of the outer peripheral wall of the building for the purpose of preventing dew condensation. In addition, since ammonia gas generated from concrete may cause deterioration of museum collections and substrate defects in semiconductor manufacturing, various measures are taken in these buildings. .. As one method, a period for withering ammonia is provided. That is, it is a method of using the building after it has been left for a predetermined period of time after the building is completed to sufficiently generate ammonia. In addition, a method of installing an ammonia adsorption sheet on the inner wall of concrete is also adopted.

【0003】

[Problems to be Solved by the Invention]

Although the conventional measures against ammonia gas have some effects, they have various drawbacks. For example, in the case of the former, there is an inconvenience that the building cannot be used until a predetermined withering period has elapsed even after the building is completed, and a large economic loss is incurred. Further, in the latter case, there is a problem that the construction is troublesome, the material cost of the adsorption sheet itself is high, and the cost burden is significantly increased.

【0004】

The present invention has been made in view of the above points, and by suppressing harmful gases such as ammonia generated from concrete, the period of withering of harmful gases conventionally provided is shortened or eliminated, and it is appropriate immediately after the building is completed. It proposes a method of shutting off harmful gas from concrete as a source, which can provide a comfortable air chamber environment, is easy to construct, and can be carried out at low cost.

【0005】

[Means for solving problems]

An air blocking layer made of synthetic resin imparts sufficient air blocking properties to suppress the generation of harmful gases such as ammonia from concrete and prevent invasion into the inside thereof. Further, among the synthetic resins, the foamed synthetic resin layer, which has been conventionally provided on the inner surface of the outer peripheral wall as a heat insulating layer for the purpose of preventing dew condensation, is used as an air blocking layer by adopting an independent foaming structure. The effect of preventing dew condensation can also be exhibited.

【0006】

The method of the first aspect of the present invention is configured as a method for blocking harmful gas originating from concrete, which is characterized in that an air blocking layer made of synthetic resin is applied and formed on the surface of a concrete skeleton.

【0007】

Further, the method of claim 2 is configured as a method of blocking harmful gas originating from concrete according to claim 1, wherein the air blocking layer is substantially a closed-cell synthetic resin foam layer.

【0008】

Further, the method according to claim 3 is configured as a method for blocking harmful gas originating from concrete according to claim 2, wherein the synthetic resin foam layer is a foamed polyurethane resin layer having a thickness of 1 mm to 50 mm.

【0009】

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

【0010】

As shown in FIG. 1, the harmful gas blocking method of the present invention suppresses the release of harmful gas from concrete by applying and forming an air blocking layer 3 made of synthetic resin on the surface of the concrete skeleton 2, and also suppresses the release of harmful gas from the inside thereof. It prevents invasion into. The air blocking layer in the illustrated example is a synthetic resin foam layer, and a in the figure indicates foaming.

【0011】

As a specific coating method of the air blocking layer, a general coating method such as coating with a brush can be adopted and is not particularly limited, but it can be preferably adopted because the coating can be efficiently sprayed.

【0012】

As the synthetic resin constituting the air blocking layer, various synthetic resins can be selected as long as they can block the passage of air, and if the coating thickness and the like are taken into consideration, most of the conventionally known synthetic resins can be used. Specific examples include thermosetting resins such as polyurethane resin, phenol resin, urea resin, melamine resin, alkyd resin, and unsaturated polyester resin, or vinyl chloride resin, acrylic resin, styrol resin, polyethylene resin, and polypropylene. Examples thereof include, but are not limited to, thermoplastic resins such as resins, polyamide resins, polycarbonates, acetal resins, and fibrous plastics.

【0013】

Further, the synthetic resin layer constituting the air blocking layer may be non-foamed or foamed. However, in the case of a foam layer, a foam layer having a substantially closed cell structure is used in order to block air. Most of the synthetic resin foams have a closed cell structure, and an air blocking layer having a substantially closed cell structure can be obtained by general foam formation without any special treatment. Foaming may be formed by a known means so as not to form an open cell structure. It should be noted that the substantially independent foaming structure includes a case where continuous foaming is slightly mixed in the molded foam layer.

【0014】

The thickness of the air blocking layer is also not particularly limited, but if it is too thin, the movement of air or moisture may not be blocked, and if it is too thick, the volume of the room will be narrowed more than necessary. A thickness of 50 mm or less is preferable.

【0015】

Basically, the part to be coated with the air blocking layer may be provided on the part of the entire exposed surface of the concrete skeleton excluding the outer peripheral surface, but at least over the entire inner surface of each section that requires a clean state. If provided, the object of the present invention can be achieved. For example, when applying an air blocking layer over the entire surface of a room that requires a clean state, or applying an air blocking layer over the entire surface of a room that requires a clean state and the entire inner surface of a required compartment such as a passage adjacent to it. Just do it.

【0016】

As described above, the resin constituting the air blocking layer is not particularly limited, but among them, the foamed polyurethane resin layer having a coating thickness of 1 mm to 50 mm has good workability, imparts good heat insulating properties, and is comprehensive. It can be adopted particularly preferably in terms of cost reduction. For example, a two-component urethane foam composed of a main agent and a curing agent can be sprayed onto a concrete surface to bring it into close contact with each other to form an air blocking layer having a substantially closed cell structure within a short period of time from construction.

【0017】

In the rigid urethane foam, the isocyanate component and the polyol component, which is a mixture of a polyol, a catalyst, a foam stabilizer, and the like, are sprayed onto the target surface in the form of mist using a spraying foamer at a constant mixing ratio and temperature. The mixed material instantly foams and hardens on the target surface, resulting in a seamless, airtight air barrier. As an example of a spray foaming machine, mainly a proportioning pump for measuring the undiluted solution to an appropriate mixing ratio, a mixing head for properly mixing the undiluted solution, and while the undiluted solution is sent to the mixing head. It consists of a heater to keep the temperature constant. An amine compound or an organometallic compound is used as the catalyst contained in the polyol component, and if the polyol component is excessively supplied, the amine compound or the like itself may become a source of ammonia gas. Machine adjustments must be made to maintain a proper mixing ratio that does not generate gas.

【0018】

The following tests were conducted to confirm the effect of the polyurethane foam layer as the air blocking layer on blocking harmful gases.

【0019】

First, a concrete test piece (200φ x 80h) collected at the site was fitted in a bottomed cylindrical non-breathable vinyl chloride container with the upper surface opened as a control, and urethane foam was applied to the concrete surface of the same test piece. Was formed by spraying to a thickness of 30 mm, and the upper surface was opened and fitted in the same container, and urethane foam having the same volume as the control was prepared in the same manner.

【0020】

Next, the following two types of tests were performed on each of the above test pieces. Test I (Distribution Law) The test piece 5 is placed in the desiccator 4 shown in FIG. 2, and the desiccator is connected to the suction pump 8 via an impinger 7 containing pure water 6 (absorbed water) inside. Then, 1 liter of air was sucked per minute with a pump, the air in the desiccator was absorbed by the pure water of the impinger, and the amount of absorbed ammonia was measured. The results are shown in Figure 3. In the figure, 9 indicates a flow meter.

【0021】

Test II (static method) The test piece was placed in a closed desiccator, and the change over time in the ammonia concentration was measured with a gas detector tube. The results are shown in Fig. 4.

【0022】

In Test I, the control was 50.6 μg / hr / m, as shown in FIGS. 3 and 4.²2.0 μg / hr / m for the test specimen sprayed with urethane against the amount of ammonia generated in²The amount generated was extremely small. In Test II, the control increased the ammonia concentration at an accelerating rate, and the ammonia concentration after 60 days was about 10 ppm, while the urethane-sprayed test specimen always showed a value close to 0. From the above results, it was found that the one provided with the polyurethane foam layer on the concrete surface is sufficiently effective in suppressing the generation of ammonia and preventing invasion.

【0023】

[Effect of the invention]

As described above, in the method for blocking harmful gas of the present invention, since an air blocking layer made of synthetic resin is applied and formed on the surface of the concrete skeleton, the generation of harmful gas such as ammonia generated from concrete is suppressed and the inside thereof is suppressed. It is possible to prevent invasion into the building and therefore provide a building with a proper air chamber environment at an early stage. Moreover, the material cost is low, the construction is easy, and the overall construction cost can be significantly reduced as compared with the construction of the adsorbent sheet.

【0024】

Further, when the air blocking layer is substantially a closed-cell synthetic resin foam layer, the effect of suppressing the generation of harmful gas from the concrete skeleton described above is exerted, and the skeleton is provided with heat insulating properties. It is given and also has the effect of preventing dew condensation due to the temperature difference between the outside air and the room.

【0025】

Further, in the case where the synthetic resin foam layer is a foamed polyurethane resin layer of 1 to 50 mm, the above-mentioned harmful gas generation prevention is performed in a state where the required space can be sufficiently secured without narrowing the indoor volume more than necessary. It can exert the effect of preventing dew condensation, and also exerts various effects such as improvement of work efficiency due to the good workability of the foamed polyurethane resin.

[Simple explanation of drawings]

[Figure 1]

It is a vertical cross-sectional view which shows an example of the wall structure in the method of this invention.

[Figure 2]

It is explanatory drawing explaining the test apparatus which measures the effect of an air barrier layer.

[Fig. 3]

It is a graph which shows the result of test I.

[Fig. 4]

It is a graph which shows the result of Test II.

[Explanation of symbols]

2 ... Concrete skeleton, 3 ... Air barrier layer, 4 ... Desiccator, 5 ... Specimen, 6 ... Pure water, 7 ... Impinger, 8 ... Suction pump, 9 ...Flowmeter