JPH075400B2 - Aqueous organosilicon composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to an aqueous organosilicon composition useful as an aqueous permeation-type water absorption inhibitor for concrete. More specifically, the present invention relates to an aqueous organosilicon-based composition, which is characterized in that an alkylalkoxysilane is aqueous emulsified using a nonionic emulsifier and an anionic emulsifier.

(Prior Art) It has been widely known that an alkylalkoxysilane is useful as a water repellent agent for building civil engineering materials such as concrete. Generally, these alkoxysilanes diluted with various solvents have been used. The range of use of such solvent-type compositions is limited by the properties of the solvent used, such as toxicity, volatility, and flammability. For example, when isopropyl alcohol, which is relatively less toxic, is used as the solvent, there is an example in which the penetration into the substrate is limited because the evaporation rate is rapid. On the other hand, when a solvent that is hard to volatilize is used, the coated surface is in a wet state and is difficult to dry, and in general, the solvent type has a problem that it cannot be coated on a wet concrete surface.

In order to solve the above problems and use alkylalkoxysilane as a permeation-type water absorption inhibitor for concrete, it is ideal to use an aqueous solution or an aqueous dispersion.
Alkoxysilanes have a strong hydrolyzability and are likely to undergo a subsequent condensation reaction, so that it has been considered extremely difficult to stably exist in water.

As a means to solve these problems, HLB has recently been 4-15
The method of aqueous emulsification of hydrolyzable organosilicon compounds such as alkyltrialkoxysilanes using the nonionic emulsifier of JP-A-62-197369 has been reported. However, a nonionic emulsifier alone tends to cause two-layer separation, and a stable aqueous emulsion cannot be easily obtained. HLB of Nonionic Emulsifier by Emulsifying Silane
It is difficult to select optimum conditions such as value, amount of emulsifier, emulsification method, etc. Further, considering the balance between waterproofness and stability or the permeability, the usable emulsifiers are limited. For example, even if the emulsifiers have the same HLB, there arises a problem that the permeability to concrete or the like changes depending on whether they are solid or liquid.

[Structure of Invention]

(Means for Solving the Problems) As a result of intensive studies to solve the above-mentioned problems, the present invention has shown that alkylalkoxysilanes are mixed with nonionic emulsifiers and anionic emulsifiers (the ratio of the anionic emulsifier to the total emulsifier is 0.01). The water-based emulsified composition of water-based emulsifying agent is not only excellent in performance stability as a permeation-type water absorption inhibitor for building materials, but also separates in appearance. It is stable and does not require detailed selection of various conditions for emulsification, so it can be easily manufactured. Even more surprisingly, it is possible to emulsify in very small amounts of less than 0.5% by weight, based on the alkylalkoxysilane.

The alkylalkoxysilane used in the present invention is not particularly limited, but at least one alkyl group directly bonded to silicon has 6 to 20 carbon atoms, and the alkoxy group may be a methoxy group, an ethoxy group or a propoxy group. Is an ethoxy group, more preferably a monoalkyltrialkoxysilane. Examples of alkylalkoxysilanes include hexyltriethoxysilane, heptyltriethoxysilane, octyltriethoxysilane,
Nonyltriethoxysilane, decyltriethoxysilane, undecyltriethoxysilane, dodecyltriethoxysilane, tridecyltriethoxysilane, tetradecyltriethoxysilane, pentadecyltriethoxysilane, hexadecyltriethoxysilane, heptadecyltriethoxysilane , Octadecyltriethoxysilane, nonadecyltriethoxysilane, eicosyltriethoxysilane, octadecylmethyldiethoxysilane,
Alternatively, a mixture thereof may be used.

When the number of carbon atoms of at least one alkyl group directly bonded to silicon is smaller than 6, the hydrolyzability and volatility are very high, so that a part of the alkyl group reacts with the surface of the base material immediately after coating, and a further aqueous composition Not only the permeation is delayed, but unreacted silane components are likely to evaporate during that time, resulting in only imparting water repellency only to the substrate surface. On the contrary, when the number of carbon atoms of at least one alkyl group directly bonded to silicon is larger than 20, the molecular weight is too large and it becomes difficult to penetrate. When the alkoxy group is a methoxy group, the stability under alkaline conditions is poor, so bonding or cross-linking easily occurs on the surface before it penetrates into the base material. As long as the stability is good, the bond with the base material becomes slow even if it penetrates into the interior. Dialkyl dialkoxy silanes and trialkyl monoalkoxy silanes other than monoalkyl trialkoxy silanes may be used in combination, although the reactivity with silanol and the like on the surface of the base material is somewhat lowered.

These alkylalkoxysilanes may be used as a method for reducing the cost without purification of the corresponding α-olefin hydrosilylated with hydroalkoxysilane. As this catalyst, a transition metal catalyst or a radical initiator used in a conventional hydrosilylation reaction of an olefin can be used. The transition metal catalyst is a transition metal complex such as platinum, cobalt, rhodium, palladium, or nickel or a halide, and the radical initiator is azobisisobutyronitrile, benzoyl peroxide, di-t-butyl peroxide, or peroxide. Examples thereof include t-butyl benzoate and the like. However, considering safety, reaction efficiency, economic efficiency, reaction conditions, etc., a method using chloroplatinic acid, which is widely used industrially, is preferable. The amount of catalyst can be set to an arbitrary amount, for example, when chloroplatinic acid is used, but it is better to reduce it as much as possible in view of both economic and hygiene. If 0.1 to 5 mmol% of chloroplatinic acid catalyst is used with respect to silane, hydrosilylation with a conversion of 98% or more can be performed by heating at 90 ° C for 5 hours. Usually, these catalysts use a solution dissolved in a solvent or the like. Since this reaction proceeds quantitatively and the catalyst requires a very small amount, it is not necessary to purify it unless there is a problem such as residual hydrosilane or catalyst toxicity.

The nonionic emulsifier to be used is not particularly limited, and examples of general nonionic emulsifiers include glycerol monostearate, glycerol monooleate, sorbitan monolaurate, sorbitan monopalminate, sorbitan monostearate, sorbitan tristearate, Sorbitan monooleate, sorbitan trioleate,
Sorbitan monosesquioleate, polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopalminate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan tristearate, polyoxyethylene sorbitan monooleate, polyoxyethylene sorbitan Trioleate, polyoxyethylene sorbitol tetraoleate, polyoxyethylene lauryl ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene higher alcohol ether, polyoxyethylene octylphenyl ether, poly Examples thereof include oxyethylene nonyl phenyl ether.

In addition to the general nonionic emulsifiers mentioned above, fluorine-based or silicone-based nonionic emulsifiers can also be used.

Examples of silicone-based nonionic emulsifiers include those represented by the formula Or expression And a polyalkylene-modified polydimethylsiloxane compound represented by

Examples of fluorine-based nonionic emulsifiers include those represented by the formula Examples thereof include a fluoroalkyl group-containing polyalkylene oxide compound and the like. The above-mentioned nonionic emulsifiers can be arbitrarily selected, but it is desirable to use a liquid nonionic emulsifier in order to produce a more stable emulsion that penetrates deeply into a building substrate such as concrete.

The anionic emulsifier used is not particularly limited, and examples thereof include sodium lauryl sulfate, triethanolamine lauryl sulfate, ammonium lauryl sulfate, sodium dodecylbenzenesulfonate, sodium alkylnaphthalenesulfonate, sodium dialkylsulfosuccinate,
Sodium alkyl diphenyl ether disulphonate, diethanolamine alkyl phosphate, potassium alkyl phosphate, sodium polyoxyethylene lauryl ether sulfate, sodium polyoxyethylene alkyl ether sulfate, triethanolamine polyoxyethylene alkyl ether sulfate, polyoxyethylene alkylphenyl Sodium ether sulfate, sodium alkane sulfonate, mixed fatty acid soda soap, semi-hardened tallow fatty acid soda soap, semi-hardened tallow fatty acid soap, sodium stearate soap, potassium oleate soap, castor oil potassium soap, higher alcohol sodium sulfate, β- Sodium salt of naphthalene sulfonic acid formalin condensate, special aromatic sulfonic acid formalin condensate, special carboxylic acid type surfactant, special poly Carboxylic acid type polymer surfactants, and the like.

The proportion of anionic emulsifiers in the total emulsifier is preferably 0.
1 to 20% by weight is desirable. If a nonionic emulsifier or an anionic emulsifier is used alone, or if the concentration of the anionic emulsifier is 20% by weight or more of the total amount of emulsifiers, it is difficult to produce a stable emulsion and the separation becomes easy and the emulsification conditions are limited.

The total amount of emulsifier is preferably 0.1 to 50% by weight of the silane component.
If it is less than 0.1% by weight, a stable emulsion cannot be obtained and the functional stability becomes poor. If it exceeds 50% by weight, sufficient water absorption preventing performance cannot be obtained. It is preferably 0.1 to 5% by weight.

A mixture of nonionic emulsifiers and anionic emulsifiers in which the proportion of anionic emulsifiers in total emulsifiers of 0.1 to 50% by weight with respect to the above-mentioned alkylalkoxysilanes and their silane components is 0.01 to 20% by weight is high-speed with a homomixer. The desired aqueous organosilicon composition is obtained by gradually adding water dropwise with stirring. Even if the emulsifier group is not completely dissolved in silane, a stable emulsion can be obtained after addition of water as long as it is homogenized by stirring. In addition, when water is added little by little, the initial concentration and viscosity may be increased, insoluble matter may be generated, and a transparent liquid may be obtained, but if the amount of water increases, a uniform emulsion will be obtained. .

Silane (organosilicon compound) of this aqueous organosilicon composition
The component concentration is preferably 1 to 70% by weight. If it is less than 1% by weight, it is not possible to impart sufficient permeation and water absorption preventing performance to concrete with one coating. Further, the second and subsequent coatings lower the permeability to that extent, so an emulsion of a dilute silane component having a concentration of 1% by weight or less is not suitable for this application. On the other hand, when it is 70% by weight or more, the viscosity becomes so high that coating becomes difficult. Although there is almost no effect of viscosity on the depth of penetration, it is recommended to use it at 50% by weight or less from the standpoints of uneven coating, slow penetration speed, and economical reasons.

(Operation of the invention) The composition thus obtained is applied to a civil engineering and construction base material such as concrete to penetrate deeply into the interior and bond therewith to form an excellent waterproof layer after drying. It is possible to prevent deterioration and provide long-term durability. Also,
Even though the composition of the present invention has an alkoxy group which is easily condensed by hydrolysis, it does not undergo thickening, gelation or deterioration in performance as a water absorption inhibitor even after storage at room temperature for 6 months. Furthermore, this composition is a stable emulsion that does not separate for a long period of time, because the droplets of the hydrophobic silane, which have been made hydrophilic by the nonionic emulsifier to some extent, are further hydrophilized by the small amount of anionic emulsifier and are stabilized in water. As described above, it was found that the composition of the present invention is an extremely useful aqueous organosilicon composition in the field of construction and civil engineering.

If necessary, additives such as dyes and pigments may be added to the composition of the present invention.

Example 1 20 g of n-octyltriethoxysilane, 3.98 g of polyoxyethylene stearyl ether and 0.02 g of sodium lauryl sulfate were mixed and stirred at a high speed of 1000 rpm or more to add water 76
By gradually adding g, a white aqueous emulsion stable at room temperature for 6 months or more was obtained.

Example 2 A white aqueous emulsion stable for 6 months or longer at room temperature was obtained in the same manner as in Example 1 except that 3.98 g of polyoxyethylene stearyl ether was replaced with 3.98 g of polyoxyethylene sorbitan trioleate.

Example 3 3.98 g of polyoxyethylene stearyl ether was SILWET
A white aqueous emulsion stable for 6 months or more at room temperature was obtained in the same manner as in Example 1 except that L-7604 (silicone nonionic emulsifier manufactured by Nippon Unicar Co., Ltd.) was changed to 3.98 g.

Example 4 3.98 g of polyoxyethylene stearyl ether was added to EFTOP E
A white aqueous emulsion stable for 6 months or more at room temperature was obtained in the same manner as in Example 1 except that 3.98 g of F-121 (a fluorine-containing nonionic emulsifier manufactured by Shin-Akita Kasei Co., Ltd.) was used.

Example 5 50 g of octadecyltriethoxysilane, 10 g of hexyltrimethoxysilane, polyoxyethylene stearyl ether
0.2g and 0.04g of sodium lauryl sulfate were mixed, stirred at a high speed of 1000rpm or more, and 40g of water was gradually added thereto to obtain a white aqueous emulsion stable at room temperature for 6 months or more.

Example 6 20 g of decyltrimethoxysilane, 7 g of polyoxyethylene nonyl phenyl ether (HLB3.5), 1.0 g of polyoxyethylene nonyl phenyl ether (HLB13.5) and 0.02 g of sodium lauryl sulfate were mixed and stirred at a high speed of 1000 rpm or more. Then, 72 g of water was gradually added thereto to obtain a white aqueous emulsion stable for 6 months or more at room temperature.

Comparative Example 1 A white aqueous emulsion was obtained by mixing 20 g of n-octyltriethoxysilane and 4 g of polyoxyethylene stearyl ether, stirring at a high speed of 1000 rpm or more, and gradually adding 76 g of water thereto, but at room temperature for 24 hours. Within two layers separated.

Comparative Example 2 20 g of n-octyltriethoxysilane, 3.60 g of polyoxyethylene stearyl ether and 1.0 g of sodium lauryl sulfate were mixed and stirred at a high speed of 1000 rpm or more and 76 g of water was added thereto.
Was gradually added to obtain a white aqueous emulsion, which separated into two layers at room temperature within 24 hours.

Comparative Example 3 20 g of n-octyltriethoxysilane, 2.00 g of polyoxyethylene stearyl ether and 2.00 g of sodium lauryl sulfate were mixed and stirred at a high speed of 1000 rpm or more, and water was added to the mixture.
A white aqueous emulsion was obtained by gradually adding g, but separated into two layers within 1 hour at room temperature.

Comparative Example 4 20 g of n-octyltriethoxysilane and 4.00 g of sodium lauryl sulfate were mixed, stirred at a high speed of 1000 rpm or more, and 76 g of water was gradually added to the mixture to effect hydration, but no emulsification occurred.

[Water absorption rate] 4 cm x 4 cm x 8 cm base mortar (JIS R5201) for 4 months
A coating amount of 300 g / m ^{2 was} applied to an air-dried product, air-dried for 28 days, and the water absorption after immersion in water for 7 days was determined according to the method of JIS A1404.

Claims (1)

[Claims] 1. A coating characterized by aqueous emulsification of an alkylalkoxysilane with a nonionic emulsifier and an anionic emulsifier in which the proportion of the anionic emulsifier in all emulsifiers is 0.01 to 20% by weight. Aqueous organosilicon composition.