JPS5855359A - Manufacture of water-repellent lightweight foamed concrete - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is based on the following methods: (1) From an aqueous slurry of calcareous raw materials and silicate raw materials, specifically quicklime, slaked lime, or Portland cement, and silica stone, aluminum metal powder or the like is used as a foaming agent;
The present invention provides a method for imparting water repellency to a product by improving the method for producing lightweight cellular concrete produced by hydrothermal curing in an autocrete using a foaming agent such as a surfactant or a foaming agent. It is.

As a method of imparting water repellency to this type of lightweight cellular concrete, it is known to add silicone oil to the aqueous slurry of the raw material, but silicone oil is expensive and mechanical Since it causes a decrease in strength, it was necessary to reduce the amount added as much as possible to achieve the same water repellent effect. The inventor is
By changing the molecular weight, or viscosity, of silicone oil,
Various attempts were made by changing the terminal group of the generator, but the addition amount was reduced to O,
When the temperature is less than S, water repellency appears or hydrothermal curing reactivity is inhibited, resulting in negative effects such as a decrease in the mechanical strength of the product, and neither of these traps was successful.

However, with the method of adding silicone oil alone to the raw material slurry, the emulsion was unstable and its dispersion in the product was insufficient, so we thought that an excessive amount of silicone oil was required. The present invention was completed as a result of research to improve the dispersibility of

The present invention provides lightweight cellular concrete with a moisture content of l- or less when producing lightweight cellular concrete from calcareous raw materials and silicic raw materials. Squid powder K 106 to IQ#@7ntestoxane adsorbed with dimethylsiloxane, based on the solid content of the raw material,
This invention relates to a novel method for producing a water-repellent lightweight cellular concrete, characterized in that the dimethyl silokina is added in an amount of 0.1 to S weight.

The technical feature of the present invention is that no emulsifying surfactant is used as a means for dispersing dimethylsiloxane in water;
The method consists of adsorbing it onto a dry lipophilic powder and dispersing the powder itself in an underwater trap.

The use of emulsifying surfactants makes it easier to stabilize aqueous compounds, but the surfactants often inhibit hydrothermal curing reactivity, and even if successful, Since the surfactant remains in the product, it becomes a water-repellent trap and reduces the water repellency of dimethylsiloxane O. Therefore, the present invention is a water-based process using dimethylsiloxane! Luci! The maximum 04I characteristic is that the raw material slurry is stably dispersed in a medium length as a powdery dispersion medium without forming 1/. As is well known, mica powder, which serves as the dispersion medium, is a mineral that becomes flaky powder even when crushed, has a large surface area per unit weight, and can adsorb dimethylsiloxane if the water content is s% or less. It's easy. Once adsorbed in this manner, dimethylsiloxane has the property of not being easily desorbed from the mica powder even when it comes into contact with water. Moreover, the actual squid powder is inert and does not substantially inhibit the hydrothermal curing reaction.

By the way, raw material powder, namely quicklime, can be prepared using a similar method.
When dimethylsiloxane is adsorbed on slaked lime, silica stone, or silica stone in a dry state, even though it is adsorbed, it is relatively easily desorbed in water. This is because the surface of these raw material powders is more hydrophilic than that of mica powder, and
This is thought to be due to the small surface area per unit weight.

As mentioned above, mica powder does not substantially inhibit the hydrothermal curing reactivity, but in the product, the matrix part that forms the walls between the bubbles may be crowded with external forces. It has the effect of appropriately dispersing the stress received from the Jl&, and as a result improves the mechanical strength of Jl&. This means that
The mica powder used in the present invention is extremely important in terms of its ability to correct the mechanical strength of the product, which decreases due to the contamination of foreign substances such as dimethylsiloxane.However, the mica powder used in the present invention does not contain moisture on the surface. If this is the case, adsorption of hydrophobic dimethylsiloxane will be difficult to occur, so it is practically necessary to keep the moisture content at 191 or less. When the surface of mica powder is dry, it is considerably more lipophilic than quicklime, slaked lime, cement mortar, and silica stone.

However, once it gets wet with water, it appears hydrophilic. Therefore, before adsorbing dimethylsiloxane,
Moisture on the surface of mica powder must be removed. ! If more than 20% of water exists on the surface of the mica powder, the adsorption ability of dimethylsiloxane decreases as the amount increases, and desorption in water becomes easier.

Although the particle size of the dimethylsiloxane that can be used in the present invention is not limited, it is preferably from 1@0 to 1Q#.0 centistokes. Namely, Zo.

Sen? When the concentration is less than
When the temperature exceeds 1u6o-Nante Stokes, mica powder adsorbed with dimethylsiloxane is dispersed in water and K<<
Therefore, if dimethylsiloxane that deviates from 100 to 10 J)00 centistokes is used, it becomes difficult to effectively exhibit the water repellency of dimethyl 5/requinane in a small amount. In addition, the mica powder used in the trap of the present invention is muscovite and 7-day govite, which are generally used for industrial purposes, and the degree of fineness thereof is not particularly limited. From the viewpoint of dispersibility of the powder in water, it is usually best to pass it through a sieve of about 30 Messier. Very finely chopped, about 3
If the material is passed through a 0.00 Messier, the amount of dimethylsiloxane adsorbed will increase, and it will also be possible to use dimethylsiloxane with a relatively low viscosity.

However, in the present invention, the optimum amount of adsorption of dimethylsilokinane to mica powder may vary depending on the combination of the particle size of mica powder and the viscosity of dimethylsiloxane, but in the present invention, the adsorption amount of dimethylsilokinane is not critical. You can choose any adsorption amount in any combination, and the hook or go/weight is easy to handle.

However, in the present invention, the amount of dimethylsiloxane is important, and is from 1 to 000% by weight, preferably from 4 to 0.6% by weight, based on the solid content of the raw material. 0.
If the weight is less than 1 weight, the water repellency of the product will be poor no matter how much the particle size of the mica powder, the viscosity of the dimethylsilokinane, the KWk, and the amount of coverage are changed. Increasing the reverse KL@weight to more than 0 water repellency is unnecessary) and is wasteful.

In the following representative examples, parts represent parts by weight ◇ Example 1 Quicklime, Portland cement, silica stone and gypsum were mixed together, 34 parts, FA and 1 part, total 100 parts, and 70 parts of water was added. In addition, a raw material slurry was made. ・Separately, phlogobite squid powder passed through a mesh sieve was dried at 100℃ for 3 hours.
In part, 1.0 centistokes of dimethylcytetraquinane 0
．． The book on which part s was adsorbed was added to the raw material slurry together with 0.07 part of metal aluminum powder and thoroughly stirred. The foam block was left to stand for a period of time until it solidified.
It was hydrothermally cured in an autoclave at 180°C to obtain lightweight cellular concrete with an absolute dry specific gravity of o and se o. When water of KO,5- was dropped on the surface of this product, the water did not form in a hemispherical shape, and no water was observed to seep into the product. Moreover, the compressive strength was about sz Ky/-.

On the other hand, when water was removed from the product without the addition of mica powder adsorbed with dimethylsiloxane, the product immediately percolated and diffused into the product. The compressive strength was approximately 49-/-.

Example 2 A similar experiment was carried out in Example X by changing the water and aluminum metal powder to brocade, o, and io parts, respectively, and a lightweight cellular concrete with an absolute dry specific gravity of O,aS and a compressive strength of 31i Kg/d was obtained. Ta. The water repellency of this product was equivalent to that of Example 1.

Patent applicant: Asahi Kasei Industries, Ltd. Agent Patent Attorney Toru Otori

Claims (1)

[Claims] (1) When producing lightweight cellular concrete from calcareous raw materials and silicic raw materials, mica powder Kh 100 to IIL@0 centistokes O dimethylsilokinane with a moisture content of 191 or less is adsorbed to the raw material solid. A method for producing water-repellent lightweight cellular concrete in which the dimethylcyp-quinane is added in an amount of 0.1 to 00@weight per minute.