JPS5849507B2 - Manufacturing method of autoclaved water-repellent lightweight cellular concrete - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the production of autoclave-cured lightweight aerated concrete using powdered siliceous and calcareous materials as main raw materials, with a viscosity of 20 to 50 at 25°C.
A silicone emulsion obtained by using 0.5 to 10 parts by weight of a surfactant composition having the following composition per 100 parts by weight of dimethylpolysiloxane with a solid content of 0 cs per 100 parts by weight of inorganic material. 0
．． Autoclave-cured water-repellent lightweight aerated concrete (abbreviation for autoclave lightweight concrete, hereinafter referred to as A) characterized by the use of 1 to 3 parts by weight
LC).

Because ALC is lighter than ordinary concrete and has low thermal conductivity, it is widely used as a heat insulating material, soundproofing material, and as a building structural material when reinforced with reinforcing steel.

This ALC is manufactured by adding a mixture of cement, lime, silicic acid powder, etc. to an appropriate amount of water, foaming it in a mold, solidifying and hardening it, and curing it in an autoclave using high-pressure steam.

The ALC manufactured in this way has many pores on its surface, and the pores inside are also open, so its water absorption rate is low. Water absorption reduces its insulation effect, and if it is used as a building material, it cannot retain heat. It does not exhibit properties such as insulation, light weight, and strength.

In order to compensate for these drawbacks, a method of applying and fixing a waterproof paint has been conventionally used.

For organic systems, emulsions of synthetic resins such as acrylic and vinyl acetate are mainly used, and for inorganic systems, white cement is mainly used.

Although it is true that products treated with these agents can prevent water absorption, they make the process complicated and increase costs.Also, since they penetrate only into the very surface layer, the surface may be scratched or deteriorated by ingestion. has the disadvantage that waterproof performance is lost.

In addition, in cold regions, moisture such as condensation water and snowmelt water can penetrate ALC and freeze, causing frost damage. Therefore, if ALC is made water-repellent not only on the surface layer but on the entire surface, it will become an excellent building material. It can meet a huge potential demand in the industry.

As a known method for imparting water repellency to the entire ALC composition, a method has been proposed in which dimethylpolysiloxane or its derivatives, fats and oils, metal salts of fatty acids, etc. are directly kneaded into a slurry prepared in a base material. .

Most of these water repellents are not practical, but dimethylpolysiloxane, which is said to be the most effective, is oily when kneaded as is, so it is difficult to separate by increasing the viscosity of the raw slurry. It is essential to prevent this or increase the amount used.

This causes the quality of ALC to deteriorate and the manufacturing cost to be increased significantly due to the provision of water repellency.

Furthermore, if the viscosity of the raw material slurry is lowered or the amount of dimethylpolysiloxane used is reduced in order to reduce costs, the water repellency becomes uneven, making it difficult to put it to practical use.

If dimethylpolysiloxane is used as an emulsion, it is possible to obtain excellent water repellency with a small amount, but conventionally,
The reasons why the emulsion was not used in ALC were (1) The presence of a surfactant in the emulsion may adversely affect the water-repellent effect.

(2) When the slurry prepared by mixing the raw materials is foamed, the bubbles are destroyed and a bumping phenomenon occurs, causing the foam to cave in.

(3) Slow hardening is observed after foaming.

(4) A large amount of air bubbles are often trapped in the raw material slurry.

(5) Decrease the bending and compressive strength of ALC.

This is because many technical problems could not be overcome.

The present inventors have arrived at the present invention as a result of intensive research aimed at overcoming these technical problems when applying these conventionally known silicone emulsions to ALC compositions.

That is, we have developed a silicone emulsion obtained by using a limited amount of a defined surfactant for a dimethylpolysiloxane with a viscosity in the range of 20 to 500 cs with a total solids content of 100% inorganic. We have discovered a method for producing ALC products with excellent water repellency that technically solves all of the above-mentioned problems by adding 0.1 to 3 parts by weight.

The structural formula of the dimethylpolysiloxane used in the silicone emulsion of the present invention is shown by, and its viscosity ranges from 0.65 cs to 1,000,000 cs. It is preferably in the range of 50 to 100 cs.

This is because dimethylpolysiloxane with a higher viscosity is difficult to form into an emulsion with the amount of surfactant used in the present invention, and problems such as bumping during foaming and slow setting are likely to occur. Those with a low viscosity range are easy to emulsify, but they have problems with adsorption to ALC substrates, so they are eluted from the substrate by high-pressure steam during autoclave curing, reducing the water-repellent effect and making them unsuitable for practical use. difficult to serve.

The surfactant silk composition used to obtain the silicone emulsion used in the practice of the present invention is (1) component A, an ester of a higher fatty acid having 1z to 22 carbon atoms and a polyhydric alcohol, or boric acid and the same higher Mixed ester of fatty acid and polyhydric alcohol...40 to 60 parts by weight (2) Component B higher fatty acid having 12 to 22 carbon atoms and molecular weight 2
Esters with polyethylene glycol of 50-4000... Song...30-5 0
Part by weight (3) Component C: Monovalent alkali metal salt of higher fatty acid having 12 to 22 carbon atoms.
...consists of 0 to 20 parts by weight.

The higher fatty acids used in the surfactant synthesis of component A of the present invention include saturated higher fatty acids such as lauric acid, palmitic acid, stearic acid, isostearic acid, and behenic acid; unsaturated higher fatty acids such as oleic acid and linolenic acid;
Examples include higher fatty acids derived from natural oils and fats such as coconut oil, beef tallow, and fish oil, and synthetic higher fatty acids, among which stearic acid is preferred.

Polyhydric alcohols used in combination with the surfactant of component A, ethylene glycol, propylene glycol,
Examples include glycerin, sorbitan, and sorbitol, with glycerin being preferred.

The fatty acid ester compound of a polyhydric alcohol of the present invention is obtained by esterifying a polyhydric alcohol with a fatty acid as described above, and is usually used in the range of monoester, diester, and triester, but the compound used in the present invention is Preferred is an anionic nonionic surfactant represented by the general formula, which is obtained by esterifying boric acid triester, which is obtained by reacting boric acid with these polyhydric alcohols, with a fatty acid.

In the formula, preferred polyhydric alcohol is glycerin, and R is preferably a saturated higher fatty acid residue having 18 carbon atoms.

The molecular weight of polyethylene glycol used in the synthesis of fatty acid ester of polyethylene glycol as component B is 2.
50 to 4400, preferably 40
Examples include polyethylene glycols having a molecular weight of 0 to 8,000.

The higher fatty acids include the same higher fatty acids used in the synthesis of component A, preferably stearic acid.

The higher fatty acid salt of component C is a monovalent alkali metal salt of the same fatty acid as the higher fatty acid used for component A, and specifically includes sodium salt and potassium 4.

The surfactant used for emulsifying the dimethylpolysiloxane of the present invention obtained in this way contains 40 to 60 parts by weight of component A, 30 to 50 parts by weight of component B, and 20 to 20 parts by weight of component C, but preferably The weight ratio of each component is 5:4:1
used at a rate of

These surfactant mixtures were mixed with dimethyl polyhexane 10
For 0 parts by weight, 0.5 to 10 parts by weight is used, and a particularly preferred amount is in the range of 1.5 to 5 parts by weight.

The silicone emulsion obtained by emulsifying these at various blending ratios has a total solid content of 0.0
As a result of producing ALC by adding in the range of 5 to 5 parts by weight and various studies from the quality aspect, we arrived at the above-mentioned blending ratio. In addition, the use of known surfactants other than these may also have an adverse effect on the quality of ALC products.
It has a negative impact on quality.

The silicone emulsion of the present invention has a viscosity of 20 to 500.
It is obtained by using limited amounts of the three components: cs dimethylpolysiloxane and the above-mentioned surfactants.

The emulsification method is usually performed by adding a limited amount of dimethylpolysiloxane having a viscosity in the above range and a limited amount of a surfactant to 50 to 80 parts by weight of warm water at a temperature of 70 to 90°C, stirring and mixing, and adding 30 to 40 parts by weight of warm water.
The mixture is cooled to 0.degree. C. and mechanically stirred using a colloid mill, homogenizer, etc. to form a fine homogeneous emulsion with a total solid content of 20 to 50 parts by weight.

If the blending ratio of each component (AXB) and (C) is other than that described above, emulsification will be poor and the oil layer will float, making it unusable.

The thus obtained emulsion of dimethylpolysiloxane of the present invention exhibits water repellency when the total solid content of the emulsion is 0.1 part by weight based on 100 parts by weight of ALC, and when 3 parts by weight or more is added. However, not only does it not improve any further, but it is also unfavorable in terms of economy and quality.

The preferred amount used is in the range of 0.5 to 1.5 parts by weight.

The silicone emulsion according to the present invention is ALC
Although the mechanism by which the above-mentioned technical problems were solved by using it as a water repellent for water repellents is not necessarily clear, the following may be considered.

(1) The hydrophobic group of the surfactant used in the present invention has excellent affinity for dimethylpolysiloxane, and also has a certain degree of waterproof property.

(2) The (AXB) component of the surfactant used in the present invention has an ester bond, and is
The instability prevents the bumping phenomenon during foaming of the raw material slurry.

(3) The surfactant used in the present invention does not significantly affect slow setting and has low foaming properties.

(4) The surfactant used in the present invention has a certain degree of water-reducing effect and has a relatively low ability to reduce interfacial tension.

Things like this are possible.

The present invention will be further explained in detail with reference to Examples below.
The present invention is not limited to this.

(1) Manufacturing method of water repellent of Examples 1 to 6 and Comparative Examples 7 to 10 ○ Manufacturing method of emulsion 70 parts by weight of water was placed in an emulsifying container, heated to 80°C, and stirred as shown in Table 1. The ingredients were added to form an emulsion with a total solids content of 30% for a total time of 60 minutes.

This emulsion was stirred with a homogenizer at 60 V for 1 minute to obtain silicone emulsions of Examples 1 to 6 and Comparative Examples 7 to 10.

Table 1 shows the component ratios of the water repellents used in the Examples and Comparative Examples prepared as described above.

(2) Manufacturing method of lightweight cellular concrete Add 0.1 to 3 parts by weight of the silicone emulsion of the present invention as a total solid content to 80 parts by weight of water, add 18 parts by weight each of cement and quicklime, 64 parts by weight of silica powder, and aluminum powder. 0.
1 part by weight of the mixture was added and stirred to form a slurry, and kneaded for 2 minutes.

Immediately after kneading, the mixture was poured into a mold for preparing a specimen, foamed at room temperature, and steam-cured ALC having an absolute dry bulk specific gravity of 0.5 was produced according to normal operations.

In addition, an emulsion-additive-free ALC was also produced in a similar manner.

For the waterproof test, a 10 CIrL square specimen was prepared, immersed in water so that the top surface was 2 CrrL below the water surface, and left for 24 hours. Expressed as a percentage of the weight of water.

The compressive strength was determined by making a 10C'm cubic specimen based on JISA5416, and the bending strength was 10cfrLX 1
A specimen of 0 CrrLX 40 cm was used for each test.

In Comparative Examples 8 and 10, the total solid content of the silicone emulsion was 0.0% relative to the inorganic substance. The water kneaded product containing 3 parts by weight or more caused severe bumping and collapsed when about 70% foamed during foaming at room temperature, and the desired ALC could not be obtained.

Also, as a result of the same test for Comparative Examples 7 and 9, a bumping phenomenon occurred when foaming was almost completed, but Comparative Examples 8 and 10
If the amount was less than <0.3 parts by weight, the desired ALC could be obtained.

In Examples 1 to 4, when the amount added was 3 parts by weight or less, there was no difference at all during foaming compared to when no additive was added, but in Examples 5 and 6, when the amount added was 2 parts by weight or more, foaming was almost completed. ”・Small bumping phenomenon occurred twice.

However, it was hardly a problem in practice.

For Comparative Examples 11 and 12, dimethylpolysiloxane was kneaded into the slurry as it was to test the waterproof performance. In order to prevent dimethylpolysiloxane from separating in the slurry, the slurry viscosity was adjusted to 800 to 1000 in Comparative Example 11.
cp in Example 12, 200 to 300 cp
Adjusted to.

Note that the amount of silicone emulsion added is o.
Test specimens containing i parts by weight or less did not exhibit water repellency sufficient for practical use.

(3) Physical properties of lightweight cellular concrete From the results in Tables 2 and 3, it is clear that the water repellent of the present invention exhibits excellent waterproof properties, and the total solid content of the silicone emulsion is the main component of ALC. Adding 0.1 part by weight to 100 parts of the raw material is practically effective, and adding 3 parts by weight almost eliminates water absorption.

Furthermore, it was observed that the bending strength and compressive strength were only reduced to such an extent that it hardly caused any practical problems, and it was confirmed that the effects of the present invention were excellent.

Claims (1)

[Claims] 1. In the production of autoclave-cured lightweight aerated concrete using powdered siliceous and calcareous substances as main raw materials, the viscosity at 25°C is 20 to 50.
A silicone emulsion obtained by using 0.5 to 10 parts by weight of a surfactant composition having the following composition per 100 parts by weight of dimethylpolysiloxane with a solid content of 0 cs per 100 parts by weight of inorganic material. Q
, 1 to 3 parts by weight of autoclave-cured water-repellent lightweight cellular concrete.