JPH0670206B2 - Inorganic building material protective agent and method for preparing the same - Google Patents

Description

TECHNICAL FIELD The present invention relates to an alkaline water-soluble protective agent used for imparting water repellency and corrosion resistance to an inorganic building material.

[Conventional technology]

Inorganic and water-absorbing building materials, such as mortar, concrete, slate, ALC, brick, roof tiles, etc., are not only water-absorbing but also water-permeable, which is a major obstacle to practical use.
Various protective treatments have been tried. As one of them, surface treatment with a silicone type treating agent is known.

As typical examples thereof, dimethylpolysiloxane oil, a solution or emulsion thereof, methylhydrogenpolysiloxane oil, a solution or emulsion thereof, a surface treatment agent with a condensate of organosilane and silicic acid, and the like are known.

[Problems to be solved by the invention]

However, these treatment agents only form a film on the surface of the building material, do not form any chemical bond with the building material, or have no affinity, and the initial water-repellent effect is insufficient or persistent. There are drawbacks such as inferiority. In addition, these building materials are exposed not only to water but also to the outside air, so corrosive substances,
For example, when sulfurous acid gas, nitrogen dioxide salt, etc. penetrate deeply into the material, the pain of the building material becomes more severe.

Particularly, in a reinforced concrete structure, the reinforcing bars are protected against rust by the highly alkaline atmosphere of the concrete, but when exposed to water and corrosive substances for a long period of time, the concrete itself is neutralized and the reinforcing bars are rusted. Occurs. Due to the volume expansion of this iron rust, concrete cracks,
Water and corrosive substances penetrate more easily and deeper from the cracks, further promoting the formation of rust. By repeating this, the concrete structure is sequentially destroyed, and it is no longer used as a structure, which may sometimes lead to a major disaster such as a personal injury.

In order to solve these problems, a silicate compound-based treatment agent was devised, but lithium silicate, which is said to have the best water resistance, easily reacts with a corrosive gas such as sulfurous acid gas to form an inorganic building material. However, it promotes the exfoliation of the backfilling agent, which is an organic compound, because it has strong alkalinity and poor affinity with organic substances.

In order to impart water repellency and corrosion resistance to such inorganic building materials, especially cement products, (1) it is an alkaline composition, (2) it has a chemical bond with or has an affinity with an inorganic substance, while an organic substance is used. Conditions such as chemically binding or having affinity with a certain backfilling agent, (3) capable of forming a gas permeable coating layer having an effect of separating water from building materials, (4) capable of capturing corrosive gas, etc. is necessary.

[Means for solving problems]

The present invention, in addition to solving the above problems, as an inorganic building material protective agent satisfying these conditions, the formula: R ¹ _n Si (OR ² ) _4-n (wherein R ¹ is methyl, ethyl, amyl, phenyl Or vinyl, R ² is methyl, ethyl, propyl, butyl or acetyl, and n is an integer of 1 to 3), and 1 to at least one silane compound of organoalkoxysilane or organoacetoxysilane 30 copies,
0.5 to 20 parts of at least one silicate compound of lithium silicate, potassium silicate and sodium silicate, and at least zinc oxide, aluminum oxide, antimony oxide, titanium oxide and tungsten oxide soluble in an alkaline aqueous solution. It has been found that a composition containing 0.5 to 15 parts of one metal oxide is optimal.

Further, although it is generally said that the organosilane is insolubilized in an alkaline aqueous solution in a short period of time, in the process of the present invention, after the organosilane is uniformly dissolved in the acidic or neutral aqueous solution, it is rapidly alkalinized with the silicate aqueous solution. It was found that by changing the amount, a stable aqueous solution can be obtained for long-term storage.

That is, the present invention dissolves 1 to 30 parts of at least one silane compound of the organosilane represented by the above formula in an acidic or neutral aqueous solution, and the aqueous solution contains lithium silicate,
0.5 to 20 parts of at least one silicate compound of potassium silicate and sodium silicate is added and dissolved, and the aqueous solution is adjusted to have an alkaline pH of 11 to 12, zinc oxide, aluminum oxide, antimony oxide, and titanium oxide. , And at least one metal oxide of tungsten oxide 0.5 to 15
It is a method for preparing an inorganic building material protective agent that dissolves parts.

INDUSTRIAL APPLICABILITY The present invention imparts water repellency and corrosion resistance to an inorganic building material, particularly a cement product, greatly improves the service life thereof, and is also used for repairing and enhancing deteriorated reinforced concrete.

The present invention will be described in more detail below.

The organosilane contained in the inorganic building material protective agent of the present invention is useful as a substance for forming the gas-permeable coating layer.

The organosilane is a compound represented by the formula, _{specifically, CH 3 Si (OCH 3)} 3, CH 3 Si (OC 2 H 5) 3, (CH 3) 2 Si (OCH 3) _{2, C 2 H 5 Si (} OC 2 H 5) 3 nC 5 H 11 Si (OC 2 H 5) 3, C 6 H 5 Si (OC 2 H 5) 3 CH 2 = CHSi (OCH 3) 3, CH _{2 = CHSi (OC 2 H 5} ) 3 CH 2 = CHSi (OCOCH 3) 3 and the like are examples.

The organosilane preferably contains at least one type of 1 to 30 parts in 100 parts of the protective agent.

If the organosilane content is less than 1 part, the coverage is poor, while
If it exceeds 30 parts, the stability as an aqueous solution is poor and the pot life becomes short, making it unusable for practical use.

As the silicate contained in the present invention, in addition to lithium silicate that captures and insolubilizes corrosive gases, those that impart alkalinity and have an affinity with building materials are preferable, and as examples of such compounds Examples thereof include water-soluble compounds such as potassium silicate and sodium silicate. It is preferable that the lithium silicate and the other silicate are contained in a total amount of 0.5 to 20 parts.

If the amount of these silicate compounds is less than 0.5 part, the affinity with building materials is insufficient, and if the amount exceeds 20 parts, the coverage of the organosilane is deteriorated.

As the metal oxide, zinc oxide, aluminum oxide, antimony oxide, titanium oxide, which are soluble in an alkaline aqueous solution,
Although tungsten oxide or the like can be used, aluminum oxide or titanium oxide is preferably used in consideration of compatibility with building materials, economy and harmlessness. 0.5 for metal oxides
It is preferable to contain ˜15 parts.

If the metal oxide content is less than 0.5 part, the covering property deteriorates, while the other 1
If the amount exceeds 5 parts, gelation of organosilane is promoted and pot life is shortened.

To obtain the protective agent of the present invention, for example, organosilane is uniformly dissolved in neutral or weakly acidic water, and a silicate is added and dissolved therein. If the silicate is difficult to dissolve, it is advisable to add the organosilane aqueous solution after making it alkaline with potassium hydroxide or the like. After dissolving the silicate,
The aqueous solution is adjusted to have a pH of 11 to 12 and then the metal oxide is dissolved.

In the alkaline region where the pH is lower than 11 and in the region where the pH is higher than 12, the organosilane lacks stability, and over time, the organosilane self-condenses to form a gel. Therefore, when adjusting the pH of the aqueous solution to be alkaline at pH 11 to 12, it is preferable to rapidly change the pH.

Fever is observed when each component is dissolved, but the water temperature is 30 ° C.
It is desirable to keep below and to dissolve the organosilane uniformly.

The protective agent of the present invention may contain other additives, if necessary, in addition to the above essential components.

The protective agent of the present invention can be used for an inorganic building material by a usual method such as coating or coating, but it is desirable because the method of coating is simple. As a method for applying to the inorganic building material, a commonly used method such as brushing, roller, spraying or the like can be used, but it is necessary to apply it uniformly and sufficiently. In addition, although natural drying is sufficient, if the drying is too fast, the protective agent may not sufficiently penetrate into the inorganic building materials, and the desired effect may not be exhibited, so in the summer when heated by direct sunlight. It is desirable to cool the construction surface with water.

Next, the preparation method of the present invention and an actual use example will be described by way of examples. In the examples, "parts" means parts by weight.

[Examples] Example 1. Preparation of Inorganic Building Material Protecting Agent: To 78 parts of water, 4 parts of methyltrimethoxysilane as an organosilane was added slowly with stirring.

Lithium silicate 12
And 2 parts of sodium silicate were added, and the mixture was stirred until it became uniform, and then the pH was adjusted to 12 with sodium hydroxide. Further, 2 parts of aluminum oxide was added to obtain a uniform transparent liquid. This liquid was stable for long-term storage.

Use for inorganic building materials: The protective agent prepared by the above method is uniformly applied at a rate of 250 ml / m ^{2 on} the entire surface of a mortar plate (50 x 50 x 25 mm) according to JIS A-1404, and then applied in a room (20 ~ It was aged at 25 ° C for 7 days.

This sample is placed at the same temperature as blank (untreated) mortar at 25 ℃.
Was immersed in water for 24 hours and the water absorbing material was measured to obtain the water absorption rate. Further, the sample used for measurement was exposed outdoors for 6 months, and then the water absorption amount was measured again under the same conditions. The water absorption rate was represented by the ratio of the water absorption amount to the blank of the treated sample.

Examples 2 to 7 A protective agent was prepared in the same manner as in Example 1 except that the compounding ratios of organosilane, lithium silicate, silicates other than lithium silicate, metal oxides, and water were changed, Similarly, the water absorption of the mortar board immediately after curing and after exposure was determined.

The results are shown in the table. The organosilane in the table was a product of Nippon Unicar. The code in parentheses indicates the product name.

Comparative Examples A and B In place of the inorganic building material protective agent of the present invention, a commercially available polymethylhydrogensiloxane treatment agent of 400 ml / m 2 was used.
² (Comparative Example A) and 500 ml / m of lithium silicate type treating agent
² (Comparative Example B) Using the same method as in Example 1, the water absorption of the mortar board immediately after curing and after exposure was determined. These results are also shown in the table.

As is clear from the table, the protective agent of the present invention has a much lower water absorption rate with respect to mortar immediately after curing and after exposure as compared with the commercially available product.

〔The invention's effect〕

The inorganic building material protective agent of the present invention has a sufficient initial water-repellent effect and is excellent in durability as compared with the conventional silicone-based processing agents and silicate-based processing agents. Therefore, the inorganic building material protective agent of the present invention imparts waterproofness and corrosion resistance to the inorganic building material, greatly improves the service life thereof, and can also be used for repairing and strengthening deteriorated reinforced concrete.

Claims (2)

[Claims] 1. A formula: R ¹ _n Si (OR ² ) _4-n (wherein R ¹ is methyl, ethyl, amyl, phenyl or vinyl, R ² is methyl, ethyl, propyl, butyl or acetyl, n is an integer of 1 to 3) 1 to 30 parts of at least one kind of silane compound of organoalkoxysilane or organoacetoxysilane represented by
0.5 to 20 parts of at least one silicate compound of lithium silicate, potassium silicate and sodium silicate, and at least zinc oxide, aluminum oxide, antimony oxide, titanium oxide and tungsten oxide soluble in an alkaline aqueous solution. An inorganic building material protective agent containing 0.5 to 15 parts of one type of metal oxide. 2. The formula: R ¹ _n Si (OR ² ) _4-n (wherein R ¹ is methyl, ethyl, amyl, phenyl or vinyl, R ² is methyl, ethyl, propyl, butyl or acetyl, n is an integer of 1 to 3) 1 to 30 parts of at least one silane compound of organoalkoxysilane or organoacetoxysilane represented by the formula (1) is dissolved in an acidic or neutral aqueous solution, and then silicic acid is added to the aqueous solution. 0.5 to 20 parts of at least one silicate compound of lithium, potassium silicate and sodium silicate is added and dissolved, and the aqueous solution is adjusted to have an alkaline pH of 11 to 12, zinc oxide, aluminum oxide, antimony oxide and oxidation. A method for preparing an inorganic building material protective agent which dissolves 0.5 to 15 parts of at least one metal oxide of titanium and tungsten oxide.