JP2003012380A - Method for producing water-repellent lightweight cellular concrete - Google Patents

Abstract

(57) To provide a method for producing water-repellent lightweight cellular concrete in which a water-repellent layer made of alkylalkoxysilane is formed on the outer surface and inner void surface of lightweight cellular concrete. SOLUTION: In a method for producing water-repellent lightweight cellular concrete by bringing alkylalkoxysilane vapor into contact with lightweight cellular concrete, a mixed gas of alkylalkoxysilane vapor and carrier gas is used, and the mixed gas in a gas reservoir is repelled. A method for producing water-repellent lightweight aerated concrete, wherein the step of allowing a lightweight aerated concrete to be formed into a water layer to flow into a reaction vessel by a gas pressure difference is performed at least twice.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a water-repellent lightweight cellular concrete having a water-repellent layer on the outer surface and the inner void surface, which is preferably used as a building material.

[0002]

2. Description of the Related Art Light weight cellular concrete is widely used as a building material for outer wall materials, floor materials, partition materials, ceiling materials, roofing materials and the like of buildings and houses because of its light weight and excellent heat insulating property. However, since it is a porous body, it easily contains water in its voids, and if it absorbs excessive water, there are problems that the heat insulating property and strength are deteriorated, and it causes frost damage in cold regions. For this reason, it is essential to design the product in consideration of its high water-absorption property, for example, by applying a coating that provides a sufficient waterproof effect or by applying a water-repellent coating material. Has become.

As a method of preventing water absorption of lightweight cellular concrete for construction, coating of the material surface is generally performed. However, since lightweight cellular concrete is a porous body, its surface and cut surface are Since there are many irregularities due to the exposure of internal voids, it is necessary to apply more paint than a material having a smooth surface in order to ensure the waterproof effect of painting. Also, when painting on-site, the coating conditions such as temperature and humidity may vary depending on the property, and it is difficult to perform high-quality painting with pinholes, etc. There is.

It is possible to secure sufficient waterproof performance for a material coated in a factory where the coating conditions are optimized, without increasing the amount of coating more than necessary.
Since building materials are often cut and processed on-site, it is necessary to rely on painting on the site for waterproofness of cut surfaces. As described above, in order to completely prevent the water absorption of the porous material by coating, it is necessary to use a large amount of coating material, so that not only the cost becomes high, but also cracks and the like are likely to occur.

Therefore, as a method for reducing the water absorption rate of lightweight cellular concrete, in JP-A-58-55359 and JP-A-3-54175, polydimethylsiloxane is added to the raw material slurry in the lightweight cellular concrete manufacturing process. A method has been proposed. However, in this method, since polydimethylsiloxane is mixed in the slurry at the raw material stage, it affects the reaction at the time of production and cannot be mixed in too much. Therefore, although such a method can solve the problem that the lightweight cellular concrete easily absorbs water, it does not essentially prevent the absorption of water, and for waterproofing, high-quality painting is still required. Was needed.

Further, Japanese Patent Application Laid-Open No. 6-271371 proposes a method in which a lightweight cellular concrete is put in a closed container to be decompressed and then a vapor of alkylalkoxysilane is introduced. However, with this method, a water-repellent layer having sufficient water repellency even inside the lightweight cellular concrete could not be obtained. Therefore, there has been a strong demand for a technique for further reducing the water absorption of lightweight cellular concrete that has been widely used in the past.

[0007]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for producing a water-repellent lightweight cellular concrete in which a water-repellent layer made of alkylalkoxysilane is formed on the outer surface and the inner void surface of the lightweight cellular concrete. And

[0008]

In order to solve the above problems, the inventors of the present invention effectively use the carrier gas and repeatedly feed the mixed gas in the gas storage container into the reaction container to effectively form the outer surface. Further, they have found that a water-repellent lightweight cellular concrete exhibiting water repellency on any cut surface can be obtained, and have completed the present invention. That is, the present invention relates to [1] a method for producing a water-repellent lightweight cellular concrete by bringing an alkylalkoxysilane vapor into contact with the lightweight cellular concrete, wherein the lightweight cellular concrete for forming a water-repellent layer is placed in a reaction vessel. After that, when the pressure of the mixed gas of the alkylalkoxysilane vapor and the carrier gas in the gas storage container is higher than the pressure of the reaction container, open the gas opening / closing means that shuts off the gas storage container and the reaction container, The pressure of the mixed gas in the gas storage container is closed after the mixed gas in the storage container is caused to flow into the reaction container in which the lightweight cellular concrete to form the water repellent layer is placed by the pressure difference. Is higher than the pressure inside the reaction vessel at that time, the gas opening / closing means is opened again, and the mixed gas in the gas storage vessel is caused to flow into the reaction vessel. Characterized in that the step is performed at least once,
Method for producing water-repellent lightweight cellular concrete, [2] In the method for producing water-repellent lightweight cellular concrete by contacting alkylalkoxysilane vapor with lightweight cellular concrete, reacting lightweight cellular concrete to form a water-repellent layer A gas opening / closing means that shuts off the gas reservoir container and the reaction container after the gas reservoir container is placed in the container and the pressure of the mixed gas of the alkylalkoxysilane vapor and the carrier gas in the gas reservoir container is higher than the pressure of the reaction container. Open
The mixed gas in the gas storage container was caused to flow into the reaction container in which the lightweight cellular concrete to form the water-repellent layer was placed by the pressure difference, and then the gas opening / closing means was closed to open or reduce the pressure of the reaction container. After that, the step of opening the gas opening / closing means again and causing the mixed gas in the gas storage container to flow into the reaction container is carried out at least once, and a method for producing a water-repellent lightweight cellular concrete.

The present invention will be described in detail below.
The lightweight cellular concrete that imparts water repellency in the present invention may be a lightweight cellular concrete that is conventionally generally produced, for example, silica stone or cement, quick lime, gypsum and the like as the main component, mixed with a foaming agent such as aluminum powder. Then, the resulting raw material slurry is poured into a mold and cured to a hardness suitable for cutting, then removed from the mold to form a semi-cured mortar block, and this is a wire rod such as a piano wire with tension. It is manufactured by subjecting the one cut in step 1 to autoclave curing.

In the present invention, an alkylalkoxysilane is represented by the general formula (R ¹ ) _n , where n is an integer from 1 to 3.
It can be represented by Si (OR ² ) _4-n . Here, R ¹ is an alkyl group having 1 to 18 carbon atoms, and R ² is not particularly limited as long as it is an alkyl group, the most general-purpose methyl group,
The ethyl group is preferred. When n is 2 or 3, R ¹ may be the same or different, and when n is 1 or 2, R ² may be the same or different.

In the present invention, the carrier gas is used for the purpose of obtaining a mixed gas having a pressure higher than the pressure in the reaction vessel in which the lightweight cellular concrete for imparting water repellency is mixed with the alkylalkoxysilane vapor. To do. The type of the carrier gas is not particularly limited as long as it has no extreme reactivity with the alkylalkoxysilane gas. For example, it may be a pure substance such as helium, argon, or nitrogen, or a mixture such as air.

The pressure of the carrier gas is set so that the pressure of the mixed gas in the gas storage container is higher than the pressure in the reaction container, so that the gas can quickly flow from the gas storage container into the reaction container. 20,000 Pa or more is preferable, 50
000 Pa or more is more preferable, and 100,000 Pa or more is particularly preferable. However, in order to increase the pressure, it is not economical to use a carrier gas having a too high pressure because the manufacturing equipment needs to have appropriate pressure resistance. In the present invention, the pressure of the carrier gas is 3,000,000.
Pa or less is preferable, 2000000 Pa or less is more preferable, and 1600000 Pa or less is particularly preferable.

By using a gas having no reactivity with alkylalkoxysilane as a carrier gas,
It is possible to prevent unnecessary hydrolysis and dehydration condensation of the alkylalkoxysilane in the gas reservoir.
As the manufacturing facility in the present invention, it is possible to use, for example, two closed containers capable of discharging internal gas, which are connected via an openable / closable gas opening / closing means, preferably an openable / closable valve. The closed container may be made of a material and strength that can withstand the temperature and pressure of the mixed gas of the alkylalkoxysilane vapor used and the carrier gas, and the capacity is not particularly limited. The alkylalkoxysilane vapor and carrier gas may be generated by heating in a container, or vapor previously generated by other equipment may be introduced.

In the present invention, the gas storage container is a container for storing the alkylalkoxysilane vapor and the carrier gas, and is a closed container capable of discharging the internal gas. The reaction container is a container in which a lightweight cellular concrete for imparting water repellency is arranged, and is a closed container from which gas inside can be discharged. In the present invention, a gas storage container containing a mixed gas of an alkylalkoxysilane vapor and a carrier gas, and a reaction container in which a lightweight cellular concrete for imparting water repellency is arranged, through a gas opening / closing means such as a valve. The gas opening / closing means is opened in a state in which the gas pressure in the gas reservoir is higher than the gas pressure in the reaction vessel by using the connected device. Then, the mixed gas in the gas storage container flows into the reaction container due to the pressure difference and reaches the inside of the lightweight cellular concrete. The alkylalkoxysilane vapor in the mixed gas promotes hydrolysis / dehydration condensation on the surface of the lightweight cellular concrete and the surface of the internal voids, thereby exhibiting water repellency.

The driving force for introducing the alkylalkoxysilane vapor deep into the lightweight cellular concrete block is the gas pressure difference resulting from the pressure difference between the gas storage container and the reaction container. The gas pressure difference referred to here is the difference between the pressure inside the reaction vessel immediately after opening the gas opening / closing means and the pressure inside the reaction vessel immediately before opening the gas opening means, that is, the reaction due to the introduction of the gas containing alkylalkoxysilane. It is the amount of increase in the pressure inside the container. If this driving force, that is, the gas pressure difference is not sufficient, water repellency cannot be exhibited even inside.

There are various types of plate thickness of lightweight cellular concrete, and the gas pressure difference required to develop water repellency to the inside cannot be said unconditionally, but for example, 100
Approximately 25,000 for mm thick lightweight cellular concrete
A pressure difference of Pa or higher, preferably 33000 Pa or higher, more preferably 50,000 Pa or higher is required. The lower limit of the gas pressure in the reaction vessel is a so-called vacuum state, and when only the alkylalkoxysilane vapor is used, the pressure difference between the gas storage vessel and the reaction vessel is the vapor of the alkylalkoxysilane at the temperature at the maximum. It is up to pressure, and it is impossible in principle to exceed it.

Alkylalkoxysilanes generally do not have a large vapor pressure, and higher temperatures are required to obtain an alkylalkoxysilane gas having a high vapor pressure. Further, when the alkyl group or the alkoxyl group has a large number of carbon atoms, the tendency becomes particularly strong. on the other hand,
An alkyl group contributes to the development of water repellency, and generally a larger alkyl group exhibits higher water repellency. Therefore,
It is more effective to use an alkylalkoxysilane having a large alkyl group to obtain high water repellency, but in that case, the gas pressure difference required to quickly fill the inside of lightweight cellular concrete is obtained. Therefore, the temperature required for it becomes high. If you try to do this, you will need equipment that can withstand higher temperatures, and even if you raise the temperature unnecessarily, the alkylalkoxysilane will decompose, and if the required gas pressure difference cannot be obtained depending on the alkylalkoxysilane. There is also. Further, even for lightweight cellular concrete to impart water repellency, it is not preferable to expose it to a temperature higher than usual manufacturing conditions.

Therefore, according to the present invention, by using a carrier gas, a gas storage container and a reaction container, which act as a driving force even under a temperature condition where a sufficient vapor pressure cannot be obtained by alkylalkoxysilane alone, are used. It was also found that the gas pressure difference can be made sufficiently large. However, when a carrier gas is used, the alkylalkoxysilane vapor contained in the mixed gas is leaner than the case where the alkylalkoxysilane vapor alone imparts water repellency at a temperature at which a sufficient pressure difference can be secured. Even if the mixed gas reaches the inside of the lightweight cellular concrete, it is often an insufficient amount for forming the water repellent layer.

In such a case, there is a method of increasing the treatment temperature to increase the content ratio of the alkylalkoxysilane vapor. However, if the mixing ratio of the carrier gas and the alkylalkoxysilane vapor is adjusted, the gas pressure can be adjusted to an arbitrary value. Since the mixed gas of is obtained, following the first water-repellent layer forming operation, after closing the gas opening / closing means, the gas pressure of the gas reservoir container is set to be equal to or higher than the gas pressure of the reaction container at that time. Fill the gas reservoir with alkylalkoxysilane vapor and carrier gas, open the gas opening / closing means,
It is possible to feed the mixed gas into the reaction vessel again.
Thus, by repeatedly sending the mixed gas containing the alkylalkoxysilane vapor from the gas storage container to the reaction container, a lightweight cellular concrete having a water repellent layer exhibiting the desired water repellent performance on the outer surface and the inner void surface. Since sufficient alkylalkoxysilane vapor can be supplied to obtain the water-repellent, excellent water-repellent lightweight cellular concrete can be obtained.

Further, following the first operation of forming the water-repellent layer, after closing the gas opening / closing means, the reaction vessel is opened, or the pressure is reduced and then the reaction vessel is closed, and the gas opening / closing means is opened to open the gas. By allowing the mixed gas in the storage container to flow into the reaction container, an excellent water-repellent lightweight cellular concrete can be obtained. For example, among alkylalkoxysilanes, in the case of hexyltriethoxysilane (alkyl group having 6 carbon atoms), octyltriethoxysilane (alkyl group having 8 carbon atoms), or alkylalkoxysilane having an alkyl group having a larger size , If the vapor pressure is low even at a temperature of 180 ° C, which is generally used for the production of lightweight aerated concrete, and the thickness of the lightweight aerated concrete is large, ensure sufficient gas pressure difference with the alkylalkoxysilane vapor alone. Is difficult, as shown in the present invention, a gas pressure difference is adjusted by using a carrier gas, and a method of repeatedly feeding an alkylalkoxysilane vapor into a reaction vessel or a method of feeding an alkylalkoxysilane vapor into a reaction vessel and then reacting once Open the container or reduce the pressure and How to feed the steam become very effective in producing excellent water repellency lightweight concrete.

In the present invention, the operation of feeding the mixed gas from the gas reservoir to the reaction vessel can be carried out at an extremely short time interval of several minutes to several tens of minutes. In the case where the water repellency imparting step is short, but partially unreacted alkylalkoxysilane is present on the outer surface of the lightweight cellular concrete and the surface of the inner voids, and it may not be possible to exhibit sufficient water repellency, In this case, the reaction proceeds by leaving it at room temperature for several days to several weeks, so that the water repellency is exhibited. It is effective to carry out a heat treatment in order to further promote the development of water repellency.
It is preferable to heat for about 5 hours. Here, the heating method is not particularly limited, but general hot air heating, far infrared heating, steam heating, or the like can be used.

As described above, the permeation into the lightweight aerated concrete is caused by the pressure difference between the gas pressure of the mixed gas of the alkylalkoxysilane vapor and the carrier gas and the gas pressure in the reaction vessel, which is the driving force. It is important to set the gas pressure of the gas higher than the gas pressure in the reaction vessel in which the lightweight cellular concrete is placed. The larger the pressure difference, the faster the gas permeates into the interior, but the water-repellent property is imparted. Total volume and thickness of lightweight cellular concrete,
Further, the most efficient and economical value can be set depending on the volume ratio of the gas storage container and the reaction container.

In the present invention, a gas mixture of an alkylalkoxysilane and a carrier gas is put in a gas container, a lightweight cellular concrete is placed in the reaction container, and the gas pressure of the mixed gas in the gas container is set to the gas in the reaction container. After making the pressure higher than the pressure, the gas opening / closing means connecting these containers is opened for a certain period of time, and then the gas opening / closing means is closed, and then a mixed gas of alkylalkoxysilane vapor and carrier gas in the gas storage container (higher than that in the reaction container Has gas pressure.)
Is introduced and the operation of opening and closing the gas shut-off means again and again for a certain period of time is performed at least once. As a result, more alkylalkoxysilane can be fed into the lightweight cellular concrete, and an excellent water-repellent lightweight cellular concrete can be obtained.

Following the first water-repellent layer forming operation, after closing the gas opening / closing means, the reaction vessel is opened, or after the pressure is reduced, the reaction vessel is closed and the gas opening / closing means is opened. By performing the operation of flowing the mixed gas in the gas reservoir into the reaction container at least once, it becomes possible to obtain an excellent water-repellent lightweight cellular concrete.
When the reaction vessel is opened or depressurized, unreacted alkylalkoxysilane vapor existing in the reaction vessel may be partly discharged to the outside of the system.To reduce the amount, open or depressurize the reaction vessel. 0.5 to 0.5 at the temperature before
It is preferable to hold for 5 hours to promote the formation of the water-repellent layer.

Furthermore, it is also possible to combine these operations. That is, following the first water-repellent layer forming operation, after closing the gas opening / closing means, the reaction vessel is opened or depressurized, while the mixed gas of alkylalkoxysilane vapor and carrier gas is placed in the gas reservoir vessel. Introduced,
It is also possible to obtain an excellent water-repellent lightweight cellular concrete by repeating the operation of opening the gas opening / closing means for a certain period of time.

[0026]

Embodiments of the present invention will be described below.

[0027]

[Embodiment 1] Inner size 200 m that can be heated by a heater
An apparatus was used in which two sealed containers each measuring m × 200 mm × 250 mm (internal volume 10 L) were connected via a valve, one was used as a gas reservoir and the other was used as a reaction container. From lightweight cellular concrete (trade name: Hebel, manufactured by Asahi Kasei Corporation), length 200 mm, width 100 mm,
A sample having a thickness of 50 mm was cut out and used as a test piece.

25 g of propyltriethoxysilane (KBE-3033, manufactured by Shin-Etsu Chemical Co., Ltd.) was placed in a gas reservoir, and the air in the container was exhausted to 1300 Pa by a vacuum pump (diaphragm vacuum pump, DAH-60). , 14
Heated to 5 ° C. The vapor pressure of propyltriethoxysilane became 27,000 Pa. Further, nitrogen gas was injected as a carrier gas into the gas storage container to raise the total pressure to 47,000 Pa. On the other hand, the above lightweight cellular concrete test piece was placed in a reaction container, heated to 145 ° C., and then the pressure inside the reaction container was reduced to 5000 Pa. After that, when the valve was opened for 10 seconds, a mixed gas of propyltriethoxysilane vapor and nitrogen flowed into the reaction container from the gas reservoir container due to the pressure difference between the two containers, and the reaction container was 260
It became 00 Pa. After the valves were closed, when the temperature of each container was maintained for 5 minutes, the propyltriethoxysilane remaining in the gas reservoir container was evaporated, and a slight pressure increase was observed.

Furthermore, the pressure in the gas reservoir is 10,000
After injecting nitrogen to 0 Pa, set the valve to 10 again.
After opening for 2 seconds, a mixed gas of propyltriethoxysilane vapor and nitrogen was further fed into the reaction vessel. The pressure of the reaction container became 63,000 Pa. After closing the valve, the reaction vessel was kept at 145 ° C. for 1 hour. The obtained test piece was cut at the central portion in the length direction, and the vicinity of the outer surface in the width direction (about 1 mm from the outer surface) on the cut surface having a width of 100 mm and a thickness of 50 mm.
2 points and 3 points at 25 mm intervals in the center, 2 points near the outer surface in the thickness direction (about 1 mm from the outer surface) and 1 in the center
The contact angle of water at 25 points at 3 points at 2.5 mm intervals was measured with a contact angle meter (CA-DT type) manufactured by Kyowa Interface Science Co., Ltd. Was about 130 degrees, and it was confirmed to have uniform water repellency.

[0030]

Example 2 Using the same apparatus as in Example 1 and a lightweight cellular concrete test piece, 25 g of propyltriethoxysilane was placed in a gas reservoir, and the air in the container was evacuated by a vacuum pump as in Example 1. Heated to 145 ° C. The vapor pressure of propyltriethoxysilane became 27,000 Pa. Further, nitrogen gas was injected as a carrier gas into the gas storage container to raise the total pressure to 100,000 Pa. On the other hand, the above lightweight cellular concrete test piece was placed in a reaction container and heated to 145 ° C.
The pressure was reduced to 00 Pa. After that, when the valve was opened for 10 seconds, a mixed gas of propyltriethoxysilane vapor and nitrogen flowed into the reaction vessel from the gas reservoir vessel due to the pressure difference between both vessels, and the reaction vessel reached 52500 Pa. After closing the valve, propyltriethoxysilane, which was present as a liquid in the gas reservoir, was evaporated and a slight pressure increase was observed.

After keeping the reaction vessel at 145 ° C. for 1 hour,
Inject nitrogen into the gas reservoir to adjust the pressure to 100,000P.
When the pressure in the reaction vessel was reduced to 5000 Pa and the valve was opened for 10 seconds, the mixed gas of propyltriethoxysilane flowed into the reaction vessel from the gas reservoir and the reaction vessel reached 52500 Pa. After closing the valve,
The reaction vessel was held at 145 ° C for 1 hour. The obtained test piece was cut at the center in the length direction to have a width of 100 mm and a thickness of 50.
Around the outer surface in the width direction on the cut surface of mm (about 1 mm from the outer surface
mm) 2 points and 3 points at 25 mm intervals in the center, 2 points near the outer surface in the thickness direction (about 1 mm from the outer surface) and 3 points at 12.5 mm intervals in the center, a total of 25 contact angles of water. Is a contact angle meter (CA-DT manufactured by Kyowa Interface Science Co., Ltd.
It was confirmed that the contact angle of water was about 130 degrees at all measurement points, and that it had uniform water repellency.

[0032]

[Example 3] Using the same apparatus as in Example 1 and a lightweight cellular concrete test piece, 25 g of hexyltriethoxysilane was placed in a gas reservoir, and the air in the container was evacuated by a vacuum pump as in Example 1. , Heated to 180 ° C. The vapor pressure of hexyltriethoxysilane was 27,000 Pa. Further, nitrogen gas was injected as a carrier gas into the gas storage container to raise the total pressure to 47,000 Pa. On the other hand, the above lightweight cellular concrete test piece was put into a reaction container, heated to 180 ° C., and then the inside of the reaction container was heated to 500 ° C.
The pressure was reduced to 0 Pa. After that, when the valve was opened for 10 seconds, a mixed gas of hexyltriethoxysilane vapor and nitrogen flowed into the reaction container from the gas reservoir container due to the pressure difference between both containers, and the reaction container became 26000 Pa. After the valves were closed, when the temperature of each container was maintained for 5 minutes, the hexyltriethoxysilane remaining in the gas reservoir container was evaporated, and a slight pressure increase was observed.
Further, nitrogen was injected until the pressure in the gas storage container reached 100,000 Pa, the valve was opened again for 10 seconds, and a mixed gas of hexyltriethoxysilane vapor and nitrogen was further fed into the reaction container. Pressure of reaction vessel is 63000P
It became a. After closing the valve, the reaction vessel was kept at 180 ° C. for 1 hour.

The test piece obtained was cut at the center in the lengthwise direction, and two points near the outer surface (about 1 mm from the outer surface) in the widthwise direction on the cut surface having a width of 100 mm and a thickness of 50 mm and a 25 mm interval at the center. At 3 points, 2 points near the outer surface (about 1 mm from the outer surface) in the thickness direction, and 3 at 12.5 mm intervals in the center.
The contact angle of water at a total of 25 points was measured with a contact angle meter (CA-DT type) manufactured by Kyowa Interface Science Co., Ltd., and the contact angle of water was about 150 degrees at all measurement points. It was confirmed to have uniform water repellency.

[0034]

[Example 4] Using the same apparatus as in Example 1 and a lightweight cellular concrete test piece, 25 g of hexyltriethoxysilane was placed in a gas reservoir, and the air in the container was evacuated by a vacuum pump as in Example 1. , Heated to 180 ° C. The vapor pressure of hexyltriethoxysilane was 27,000 Pa. Further, nitrogen gas was injected as a carrier gas into the gas storage container to raise the total pressure to 100,000 Pa. On the other hand, the above lightweight cellular concrete test piece was put into a reaction vessel, heated to 180 ° C., and then heated to 50 ° C. in the reaction vessel.
The pressure was reduced to 00 Pa. After that, when the valve was opened for 10 seconds, a mixed gas of hexyltriethoxysilane vapor and nitrogen flowed into the reaction container from the gas reservoir container due to the pressure difference between both containers, and the reaction container became 52500 Pa. After closing the valve, propyltriethoxysilane, which was present as a liquid in the gas reservoir, was evaporated and a slight pressure increase was observed.

After keeping the reaction vessel at 180 ° C. for 1 hour,
Inject nitrogen into the gas reservoir to adjust the pressure to 100,000P.
When the pressure in the reaction vessel was reduced to 5000 Pa and the valve was opened for 10 seconds, the mixed gas of hexyltriethoxysilane flowed into the reaction vessel from the gas reservoir vessel, and the reaction vessel reached 52500 Pa. After closing the valve,
The reaction vessel was kept at 180 ° C. for 1 hour. The obtained test piece was cut at the center in the length direction to have a width of 100 mm and a thickness of 50.
Around the outer surface in the width direction on the cut surface of mm (about 1 mm from the outer surface
mm) 2 points and 3 points at 25 mm intervals in the center, 2 points near the outer surface in the thickness direction (about 1 mm from the outer surface) and 3 points at 12.5 mm intervals in the center, a total of 25 contact angles of water. Is a contact angle meter (CA-DT manufactured by Kyowa Interface Science Co., Ltd.
The contact angle of water was about 150 degrees at all measurement points, and it was confirmed that the sample had uniform water repellency.

[0036]

Comparative Example 1 In comparison with the method described in Example 1, the water repellency was examined when the mixed gas of propyltriethoxysilane and nitrogen was fed into the reaction vessel only once.
Using the same apparatus as in Example 1 and a lightweight cellular concrete test piece, propyltriethoxysilane 25 was placed in a gas reservoir.
g was added, the air in the container was evacuated by a vacuum pump as in Example 1, and then heated to 145 ° C. The vapor pressure of propyltriethoxysilane became 27,000 Pa. At this point, add nitrogen gas to the gas reservoir and adjust the total pressure to 47
Raised to 000Pa. On the other hand, the above lightweight cellular concrete test piece was placed in a reaction container, heated to 145 ° C., and then the pressure inside the reaction container was reduced to 5000 Pa. Then turn the valve 1
When opened for 0 seconds, a mixed gas of propyltriethoxysilane vapor and nitrogen flows from the gas reservoir to the reaction vessel due to the pressure difference between the two vessels, and the reaction vessel has a pressure of 26000 Pa.
Became. After closing the valve, place the reaction vessel at 145 ° C for 1 hour.
Held for hours.

The obtained test piece was cut at the center in the length direction, and two points were formed in the width direction on the cut surface having a width of 100 mm and a thickness of 50 mm in the vicinity of the outer surface (about 1 mm from the outer surface) and at intervals of 25 mm in the center. At 3 points, 2 points near the outer surface in the thickness direction (about 1 mm from the outer surface), and 3 points at 12.5 mm intervals, for a total of 25 contact angles of water. When measured with (CA-DT type), 1 from the surface
The contact angle of water is about 13 at 22 points within 2.5 mm.
Although it was 0 degree, the contact angle was less than 90 degrees at three points with a depth exceeding 12.5 mm from the surface. In order to investigate the details of the water-repellent part, the contact angle of water was measured at 5 mm intervals in the thickness direction at the center of the cut surface in the width direction, and it was about 130 degrees at a point within 20 mm from the surface. However, it was less than 90 degrees at one point in the central part.

[0038]

Comparative Example 2 In comparison with the method described in Example 2, the water repellency was examined when the mixed gas of propyltriethoxysilane and nitrogen was fed into the reaction vessel only once.
Using the same apparatus as in Example 1 and a lightweight cellular concrete test piece, propyltriethoxysilane 25 was placed in a gas reservoir.
After adding g, the air in the container was evacuated with a vacuum pump as in Example 1, and then heated to 145 ° C. The vapor pressure of propyltriethoxysilane became 27,000 Pa. Further, nitrogen was injected as a carrier gas into the gas reservoir to raise the total pressure to 100,000 Pa. On the other hand, the above lightweight cellular concrete test piece was placed in a reaction container, heated to 145 ° C., and then the pressure inside the reaction container was reduced to 5000 Pa. After that, when the valve was opened for 10 seconds, a mixed gas of propyltriethoxysilane vapor and nitrogen flowed into the reaction vessel from the gas reservoir vessel due to the pressure difference between both vessels, and the reaction vessel reached 52500 Pa. After closing the valve,
The reaction vessel was held at 145 ° C for 1 hour.

The test piece obtained was cut at the center in the lengthwise direction, and two points near the outer surface (about 1 mm from the outer surface) in the widthwise direction on the cut surface having a width of 100 mm and a thickness of 50 mm and a 25 mm interval at the center. At 3 points, 2 points near the outer surface (about 1 mm from the outer surface) in the thickness direction, and 3 at 12.5 mm intervals in the center.
The contact angle of water at a total of 25 points was measured with a contact angle meter (CA-DT type) manufactured by Kyowa Interface Science Co., Ltd., and the contact angle of water was 22 points within 12.5 mm from the surface. Although it was about 130 degrees, the contact angle was less than 90 degrees at three points with a depth exceeding 12.5 mm from the surface. In order to investigate the details of the water-repellent part, the contact angle of water was measured at 5 mm intervals in the thickness direction at the center of the cut surface in the width direction, and it was about 130 degrees at a point within 20 mm from the surface. However, one point in the center was 9
It was less than 0 degrees.

[0040]

COMPARATIVE EXAMPLE 3 In comparison with the method described in Example 3, the water repellency was examined when the mixed gas of hexyltriethoxysilane and nitrogen was fed into the reaction vessel only once.
Using a device similar to that of Example 1 and a lightweight cellular concrete test piece, hexyltriethoxysilane 25 was placed in a gas reservoir.
After adding g, the air in the container was evacuated by a vacuum pump as in Example 1, and then heated to 180 ° C. The vapor pressure of hexyltriethoxysilane was 27,000 Pa. Further, nitrogen gas was injected as a carrier gas into the gas storage container to raise the total pressure to 47,000 Pa. On the other hand, the above lightweight cellular concrete test piece was placed in a reaction container, heated to 180 ° C., and the pressure inside the reaction container was reduced to 5000 Pa. After that, when the valve was opened for 10 seconds, a mixed gas of hexyltriethoxysilane vapor and nitrogen flowed into the reaction container from the gas reservoir container due to the pressure difference between both containers, and the reaction container became 26000 Pa. After closing the valve, the reaction vessel was kept at 180 ° C. for 1 hour.

The test piece obtained was cut at the central portion in the lengthwise direction, and two points near the outer surface (about 1 mm from the outer surface) in the widthwise direction on the cut surface having a width of 100 mm and a thickness of 50 mm and the widthwise direction at the central portion. 3 points at 25 mm intervals, 2 points near the outer surface in the thickness direction (about 1 mm from the outer surface) and 12.5 m in the center
The contact angle of water at a total of 25 points at 3 points at m intervals was measured with a contact angle meter (CA-DT type) manufactured by Kyowa Interface Science Co., Ltd., and water was detected at 22 points within 12.5 mm from the surface. Contact angle was about 150 degrees, but 12.5 from the surface
The contact angle was less than 90 degrees at three points with a depth exceeding mm. In order to investigate the details of the part where water repellency is expressed, 5 in the thickness direction at the center of the cut surface in the width direction.
When the contact angle of water was measured at mm intervals, it was 20
It was about 150 degrees at a point within mm, but it was less than 90 degrees at one point in the central portion.

[0042]

COMPARATIVE EXAMPLE 4 In comparison with the method described in Example 4, the water repellency was examined when the mixed gas of hexyltriethoxysilane and nitrogen was fed into the reaction vessel only once.
Using a device similar to that of Example 1 and a lightweight cellular concrete test piece, hexyltriethoxysilane 25 was placed in a gas reservoir.
After adding g, the air in the container was evacuated by a vacuum pump as in Example 1, and then heated to 180 ° C. The vapor pressure of hexyltriethoxysilane was 27,000 Pa. Further, nitrogen was injected as a carrier gas into the gas reservoir to raise the total pressure to 100,000 Pa. On the other hand, the above lightweight cellular concrete test piece was placed in a reaction container, heated to 180 ° C., and the pressure inside the reaction container was reduced to 5000 Pa. After that, when the valve was opened for 10 seconds, a mixed gas of hexyltriethoxysilane vapor and nitrogen flowed into the reaction container from the gas reservoir container due to the pressure difference between both containers, and the reaction container became 52500 Pa. After closing the valve,
The reaction vessel was kept at 180 ° C. for 1 hour.

The obtained test piece was cut at the central portion in the lengthwise direction, and two points near the outer surface (about 1 mm from the outer surface) in the widthwise direction on the cut surface having a width of 100 mm and a thickness of 50 mm and a 25 mm interval at the central portion. At 3 points, 2 points near the outer surface in the thickness direction (about 1 mm from the outer surface), and 3 points at 12.5 mm intervals, for a total of 25 contact angles of water. When measured with (CA-DT type), 1 from the surface
At 22 points within 2.5 mm, the water contact angle is about 15
Although it was 0 degree, the contact angle was less than 90 degrees at three points with a depth exceeding 12.5 mm from the surface. In order to examine the details of the water-repellent part, the contact angle of water was measured at 5 mm intervals in the thickness direction at the center of the cut surface in the width direction, and it was about 150 degrees at a point within 20 mm from the surface. However, it was less than 90 degrees at one point in the central part.

[0044]

According to the method of the present invention, the production of a water-repellent lightweight cellular concrete that exhibits water-repellent performance by forming a water-repellent layer made of an alkylalkoxysilane on the surface of the lightweight cellular concrete and the surface of the internal voids. In the method, the same alkylalkoxysilane can be treated at a lower temperature than before. Moreover,
It was difficult to permeate the inside of lightweight cellular concrete as vapor due to its low vapor pressure. It became easy to use an alkylalkoxysilane having a large alkyl group as a water repellent, and various water repellent lightweight cellular concretes were It is easier to manufacture.

Claims (2)

[Claims] 1. A method for producing a water-repellent lightweight cellular concrete by bringing an alkylalkoxysilane vapor into contact with the lightweight cellular concrete, after arranging the lightweight cellular concrete for forming a water-repellent layer in a reaction vessel,
When the pressure of the mixed gas of the alkylalkoxysilane vapor and the carrier gas in the gas storage container is higher than the pressure of the reaction container, open the gas opening / closing means that isolates the gas storage container from the reaction container, and open the gas storage container. After the mixed gas is caused to flow into the reaction container in which the lightweight cellular concrete to form the water repellent layer is placed by the pressure difference, the gas opening / closing means is closed, and the pressure of the mixed gas in the gas storage container is changed to The pressure in the reaction vessel at the time point is made higher, the gas opening / closing means is opened again, and the step of causing the mixed gas of the gas reservoir vessel to flow into the reaction vessel is performed at least once. Production method. 2. A method for producing a water-repellent lightweight cellular concrete by bringing an alkylalkoxysilane vapor into contact with the lightweight cellular concrete, after arranging the lightweight cellular concrete for forming a water-repellent layer in a reaction vessel,
When the pressure of the mixed gas of the alkylalkoxysilane vapor and the carrier gas in the gas storage container is higher than the pressure of the reaction container, open the gas opening / closing means that isolates the gas storage container from the reaction container, and open the gas storage container. After the mixed gas is caused to flow into the reaction vessel in which the lightweight cellular concrete to form the water-repellent layer is placed by the pressure difference, after closing the gas opening / closing means and opening or reducing the pressure of the reaction vessel,
A method for producing a water-repellent lightweight cellular concrete, characterized in that the step of opening the gas opening / closing means again and injecting the mixed gas in the gas reservoir into the reaction vessel is performed at least once.