JPS6214514B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing waterproof steam-cured lightweight cellular concrete. Steam-cured lightweight cellular concrete is made by mixing siliceous raw materials such as silica sand and silica stone and calcareous raw materials such as lime and cement in an appropriate proportion with water, then adding metal powder such as aluminum and stirring, or After incorporating air bubbles by a method such as mixing air, the material is solidified and hardened, and then transferred to an autoclave and subjected to high-temperature, high-pressure steam curing. The lightweight cellular concrete produced in this manner has a large number of pores on its surface and has many open pores inside, so it has high water absorption. In order to prevent water absorption in these lightweight cellular concretes used as building materials, a conventional method has been to apply a waterproof paint to the surface of a product panel of steam-cured lightweight cellular concrete and to fix it. There are various types of paints, and generally, organic paints are solvent type or emulsion type resin paints, and inorganic paints are cement type paints. Items treated with these paints can certainly prevent water absorption, but they only penetrate into the surface layer, and if the surface is scratched or deteriorates due to outdoor exposure, the waterproof performance will be impaired. . However, it is strongly desired that waterproof performance be provided not only to the surface layer of the material but also to the deep layer. In order to solve this problem, the inventors filed a patent application in 1973.
- No. 116202, Patent Application No. 162078, and Patent Application No.
No. 53-165206 discloses a method for producing steam-cured lightweight aerated concrete using powdered silicic raw materials and calcareous raw materials as main raw materials, in which silicone oil consisting of dimethylsiloxane and dimethylsiloxane derivatives is added to the raw material slurry mixture, and methyl A method of adding silicone oil consisting of one or both of phenylsiloxane and chlorophenylmethylsiloxane, adding at least one of phenylmethylsilicone varnish, methylsilicone varnish, and modified products of these varnishes, and steam curing. has been applied for. According to these methods, the drawbacks of the method of imparting waterproofness by applying paint to the surface of steam-cured lightweight cellular concrete can be eliminated, and steam-cured lightweight cellular concrete can be obtained that has waterproof properties throughout the material. However, since the silicon compound used in this case is quite expensive, it is industrially desirable to reduce the amount added as much as possible, and to obtain lightweight cellular concrete with no inferior waterproof performance.
The present invention aims to provide a method for producing lightweight cellular concrete that satisfies this demand. In order to achieve this object, the present invention has invented the manufacturing method described in the claims. The lightweight cellular concrete obtained by the method of the present invention has silicone oil or silicone varnish as a raw material, although its waterproofness varies depending on the amount of silicone oil or silicone varnish added and the amount of resin added. 0.1 to 5% by weight based on solid content
When adding 0.01 to 0.5% by weight of resin solids based on the solid content of the raw materials, the same level of waterproofing can be achieved even if the amount added is reduced to about half of that when only silicone oil or silicone varnish is added. It is possible to obtain a product with properties. In general, products such as silicone oil and silicone varnish that have siloxane bonds as structural units and hydrophobic methyl groups in their side chains often cannot be mixed uniformly with slurry-like products, but By setting the viscosity of the slurry to 100 cp or more, the silicone oil can be uniformly dispersed, and the whole can have uniform waterproof performance.
I have never seen an example of using silicone oil or silicone varnish in this way to achieve a waterproof effect. The raw materials for lightweight cellular concrete used include calcareous raw materials such as lime or cement, silicic raw materials such as silica stone, silica sand, blast furnace slag, fly ash, etc., foaming agents, aluminum powder,
The surfactant and the like are not particularly limited as long as they are commonly used. The silicone added to the raw material slurry, which is a feature of the present invention, has various properties, but those that are effective when used in the method of the present invention are dimethylsiloxane, dimethylsiloxane derivatives, methylphenylsiloxane, and chlorophenylmethyl. Silicone oil consisting of siloxane, phenylmethyl silicone varnish, methyl silicone varnish, modified products of these varnishes, and the structural formula of dimethylsiloxane is (In the formula, n indicates the degree of polymerization with a viscosity of 10,000 cs or less at 25°C.) In addition, dimethylsiloxane derivatives are those in which part or all of the methyl groups in the above formula are amino groups,
polyether, olefin, epoxy group, fluorine,
It is suitable for use if it is made of α-methylstyrene or an alcohol-substituted derivative, and both have a viscosity of 10,000 cs or less at 25°C. Methylphenylsiloxane is dimethylsiloxane with some of the methyl groups replaced with phenyl groups, and the 10% modified version has a viscosity at 20°C.
100cs, 45% metamorphosis is 500cs. Those with a phenyl modification content of 45% or more are solid and not oily, so they are difficult to use. In addition, chlorphenylmethyl silicone oil is dimethylsiloxane in which some of the methyl groups are replaced with phenyl groups and chlorine, and the phenyl modification rate is 20.
%, Chlor transformation rate is viscosity up to 3-6.5%
100cs is good. Bromophenylmethylsiloxane, fluorophenylmethylsiloxane, and iodophenylmethylsiloxane can also be used, but they are easily hydrolyzed and unstable. There are silicone varnishes with various properties, but those that are effective when used in the method of the present invention are phenylmethyl silicone varnishes, methyl silicone varnishes, or silicone varnishes made of modified products thereof; methyl silicone varnishes are Generally SiO ₂ , CH ₃ SiO _3/2 , (CH ₃ ) ₂ SiO,
It is a copolymer made by combining structural units of (CH ₃ ) ₃ SiO _1/2 . Phenylmethyl silicone varnishes are generally CH ₃ SiO _3/2 , (CH ₃ ) ₂ SiO,
_{C6H5SiO3 /2 , ( C6H5 )} ( _CH3 )SiO, ( _C6H5 ) _2SiO
It is a copolymer made by combining the structural units of These modified products include blends or copolymerizations of straight silicone varnish with other organic monomers and polymers, such as alkyd, epoxy, acrylic, polyester, melamine, and phenolic resins. A material with a viscosity of 10,000 cs or less at 25°C is suitable for use. The amount of silicone oil or silicone varnish with the above structure is based on the solid content of the raw material mixture.
In both cases, the waterproof effect was observed when 0.1% by weight or more was added, and even when silicone oil was added at 4 to 5% by weight or more, and silicone varnish was added at 5% by weight or more, the water absorption did not improve any further. Examples of resins that can be added in combination with silicone oil or silicone varnish include acrylic ester,
A resin emulsion whose composition is a polymer of the following monomers: methacrylic acid ester, versatile vinyl ester, vinyl acetate, ethylene, vinyl chloride, vinylidene chloride, butadiene, styrene, chloroprene, acrylonitrile, isobutylene, chlorostyrene, and vinyl propionate; A mixture of one or more types selected from natural rubber latex emulsion and water-soluble synthetic resins such as cellulose derivatives, polyvinyl alcohol, acrylates, furfuryl alcohol, and acrylamide, and is generally used for cement mixing. It is used to improve the elongation, adhesion, and shrinkage of mortar, and all of them are commercially available with a resin solid content of 20 to 70% by weight. The added amount of the above resin is combined with the above added amount of silicone oil or silicone varnish, and the effect of addition is recognized when it is added in an amount of 0.01% by weight or more based on the solid content of the raw material mixture. Waterproofness is better than when added,
Addition of 0.5% by weight or more did not increase the effect. The raw material mixture may be stirred using a commonly used stirrer such as a paddle or propeller. The viscosity of the raw material mixture is determined using a rotor viscometer (manufactured by Rion) at 25℃, and is 100 to 1000 cp.
A range of is desirable. If the viscosity is less than 100cp, the silicone oil will separate and uniform dispersion cannot be expected. Moreover, if it exceeds 1000 cp, the foaming condition will be extremely poor, which is not preferable. If the formulation lacks viscosity, a thickener such as bentonite, polyvinyl alcohol, or cellulose may be added as necessary. For steam curing in an autoclave after foam molding, general conditions such as saturated steam at a gauge pressure of 10 Kg/cm ² and a temperature of about 180° C. may be used. Examples will be described below. Example 1 6 parts by weight of powdered quicklime, 22 parts by weight of Portland cement, 32 parts by weight of silica powder, 0.05 parts by weight of aluminum powder, 40 parts by weight of water, based on the total amount of the solid content , a silicone oil consisting of 0.1 to 5% by weight of dimethylsiloxane and an acrylic vinyl acetate copolymer resin emulsion with a resin solid content of 0.01 to 1.0% by weight were added and stirred to form a slurry, and steam-cured according to normal operations. Lightweight aerated concrete is produced, and its waterproof performance is tested by cutting out a 10 cm square sample, immersing it in water so that the top surface is 2 cm below the water surface, and leaving it for 24 hours.The weight increase due to water absorption is equal to the volume of the sample. Expressed as a percentage of the weight of water. The waterproof performance test results are shown in the table below.

[Table] From this result, even if the amount of resin added is 0.01% by weight,
It is found that silicone oil is effective in improving waterproofness compared to silicone oil added alone, but adding more than 0.5% by weight has no effect on improving waterproofness, and when the amount of silicone oil added exceeds 5.0% by weight, it is no longer effective. The waterproof performance did not improve any further. Example 2 6 parts by weight of powdered quicklime, 22 parts by weight of Portland cement, 32 parts by weight of silica powder, 0.05 parts by weight of aluminum powder, 40 parts by weight of water, based on the total amount of the solid content , a silicone oil consisting of methylphenylsiloxane of 0.1 to 5% by weight and a styrene-butadiene copolymer resin latex emulsion of 0.01 to 1.0% by weight as resin solids were added and steam-cured in the same manner as in Example 1. Lightweight aerated concrete was manufactured and its waterproof performance was investigated. The results are also listed in the table below.

【table】

[Table] According to the results, when the amount of resin added is 0.01% by weight, an effect in combination with silicone oil is recognized, when the amount of resin added is 0.5% by weight or more, there is no effect on improving waterproofness, and when the amount of silicone oil added is 4.0% by weight. The waterproof performance was sufficient. Example 3 A mixture of quicklime powder, cement, silica powder, aluminum powder, and water in the same proportions as in Example 1 was mixed with methyl silicone varnish in an amount of 0.1 to 7% by weight based on the total solid content, and also as resin solid content. 0.01
~1.0% by weight of ethylene-vinyl acetate copolymer resin emulsion was added to produce steam-cured lightweight cellular concrete in the same manner as in Example 1, and its waterproof performance was examined. The results are shown in the table below.

[Table] According to the results, the effect of adding resin was greater in Example 2.
The effect was similar to that of the above, and the waterproof performance no longer improved even when the amount of silicone varnish added exceeded 5% by weight. The mechanical strength of these test pieces was also examined, and the strength did not decrease due to the addition of silicone oil, silicone varnish, and resin. Example 4 In place of the resins used in Examples 1 to 3, namely acrylic vinyl acetate copolymer resin emulsion, styrene butadiene copolymer resin latex emulsion, and ethylene vinyl acetate copolymer resin emulsion, other resin emulsions described above were used. Although natural rubber latex emulsion and water-soluble synthetic resin were used, almost the same results as in the previous example were obtained regarding waterproof performance.

Claims (1)

[Claims] 1. In a method for producing steam-cured lightweight cellular concrete using powdered silicate raw materials and calcareous raw materials as main raw materials, dimethylsiloxane, dimethylsiloxane derivatives, methylphenylsiloxane, and chlorophenylmethylsiloxane are added to a slurry mixture of the raw materials. 0.1 to 5% by weight of at least one of silicone oil, phenylmethyl silicone varnish, methyl silicone varnish, and modified products of these varnishes based on the total solid content in the raw material slurry mixture, and acrylic ester and methacrylic acid. Resin emulsions containing polymers of the following monomers: ester, vinyl versatate, vinyl acetate, ethylene, vinyl chloride, vinylidene chloride, butadiene, styrene, chloroprene, acrylonitrile, isobutylene, chlorostyrene, vinyl propionate, natural rubber. latex emulsion and at least one of water-soluble synthetic resins such as cellulose derivatives, polyvinyl alcohol, acrylates, furfuryl alcohol, and acrylamide in an amount of 0.01 to 0.5% by weight based on the total solid content in the raw material slurry mixture. A method for manufacturing waterproof steam-cured lightweight aerated concrete characterized by adding additives.