JPH03127667A - Method for protecting porous civil engineering and construction material - Google Patents

Abstract

PURPOSE:To obtain the material having water absorptive and waterproof properties and water repellency by applying or impregnating an org. solvent soln. of an org. silicon compd. on or in the surface of porous civil engineering and construction materials, then applying an org. solvent of the lower polymer of the org. silicon compd. CONSTITUTION:The org. solvent soln. of the org. silicon compd. expressed by formula I (where R1 denotes 1 to 18c satd. alkyl group; R2 denotes 1 to 5C satd. alkyl group; n denotes 1 to 6 integer) is applied or impregnated on or in the surface of the porous civil engineering and construction materials consisting of concrete, mortar, etc. The water absorptivity of the porous civil engineering and construction materials is prevented. The org. solvent soln. of the low polymer of the org. silicon compd. expressed by formula II (where R3 denotes 1 to 18C satd. alkyl group; X denotes a hydroxyl group, 1 to 18C satd. alkyl group, etc.; m denotes 7 to 18 integer). The water repellency is then imparted to the civil engineering and construction materials. The water absorptivity and the water repellency are obtd. in combination in this way without changing the air permeability and appearance.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for protecting porous civil engineering and building materials. In more detail, we will cover exposed concrete, lightweight concrete, precast concrete, lightweight cellular concrete (ALC), mortar, asbestos cement board, calcium silicate board, pulp cement board, wood wool cement board, gypsum board, hardboard, plaster, brick, Blocks, tiles, gypsum plaster, dolomite plaster, natural stone, artificial stone, glass wool, and other porous civil engineering and building materials whose main components are inorganic materials, and surfaces of porous civil engineering and building materials whose main components are organic materials such as wood, plywood, and particle board. The present invention relates to a method for protecting civil engineering and construction materials, which improves the water resistance of the material by forming a layer that is both waterproof and water repellent.

Note that the above-mentioned porous civil engineering and construction materials may be simply referred to as "materials" hereinafter.

(Prior Art) (Problems to be Solved by the Invention) Generally, when the above-mentioned porous civil engineering and construction materials are exposed to the natural environment, in addition to deterioration due to sunlight, there are also cases where the deterioration due to water is very large. . For example, water from wind and rain may penetrate into the material and cause the material to deteriorate, or the water may expand in volume due to freezing in the winter, causing cracks on the surface of the material, or in severe cases, the material itself may be destroyed. It may lead to. In addition, corrosive substances in the air may enter the material together with rainwater and damage the material, or dirt and dust may adhere to the surface, staining the surface, or mold may form. A problem arose in which sexuality was inhibited.

Another problem is that water-soluble substances in the material seep to the surface, causing an effro phenomenon.

Conventionally, methods for preventing the above-mentioned deterioration and inhibition of cosmetic appearance caused by water with respect to such porous civil engineering and construction materials include: 1) Applying a coating material such as paint to make the material water repellent.

2) A method of applying a water-repellent compound such as paraffin oil or silicone oil.

3) General formula RTI 5i-(OR)4-71 (where n is 1) such as methoxytrimethylsilane, dimethoxydimethylsilane, trimethoxymethylsilane, ethoxytrimethylsilane, jetoxydimethylsilane
, 2.3, and other methods of imparting water repellency and waterproofness to the surface of the material are known.

However, method 1) (a) tends to cause cracking and peeling of the coating film, leading to a decrease in the water repellent effect in a short period of time.

Many of these coating materials have low water vapor permeability, and water that has entered the material before painting, or water that has entered through cracks, crevices, unpainted areas, and other non-waterproof areas, can be released as water vapor. Since it is not released into the atmosphere, it is confined within the material, resulting in material deterioration and destruction due to freezing.

In method 2), a) the coating agent penetrates only into the surface, so if the surface is scratched or deteriorated due to outdoor exposure, the water repellent effect will be rapidly lost. (Note) It does not blend well with the material, especially if it is on a vertical surface, and within a long period of time after application, the drug will drip and the water repellent effect will be lost from the top. c) It has poor alkali resistance and loses its water-repellent effect within a short period of time. 2) dust,
Easy to get dirt such as dust.

There are drawbacks such as.

Method 3) is an excellent method because the applied material has both water repellency and air permeability, but since the silane compound used has a relatively low molecular weight, Although it penetrates, it has a high vapor pressure and tends to scatter before reacting with water to form a water-repellent layer, resulting in poor waterproofing effects.

As described above, neither method is satisfactory in terms of long-term stability of water repellent effect.

(Means for solving the problem) As a means for solving the above-mentioned problem regarding the long-term stability of the water repellent effect, Japanese Patent Application Laid-Open No. 56-27475 discloses R2-8i -(OR'), A method is disclosed in which the surface of a porous material to be protected is treated in advance by a high-pressure cold water method, a steam injection method, or the like before applying the organoalkoxysilane compound represented by the following formula. Sara 1
= JP-A-63-103879 discloses a method characterized by intentionally bringing a part of a building material to be made water repellent into contact with liquid water before applying a solution of an organosilicon compound. Disclosed. According to these methods, the chemical penetrates deeper than in the case where such pretreatment is not performed, and a water repellent effect can be stably obtained over a long period of time.

In addition, the present inventors used a siloxane oligomer, which is a low condensate thereof, instead of an organoalkoxysilane compound, dissolved it in an organic solvent miscible with water among alcohol, ether, and ketone, and applied it. For example, as mentioned above, we discovered that the chemical can penetrate deeply into the material without pre-treatment such as treating the surface of the material with water, and can prevent the water absorption of the material for a long period of time without scattering into the atmosphere. Ta. (Patent application filed on July 6, 1999 for "Method for preventing water absorption of porous inorganic civil engineering and construction materials". Patent application filed on July 6, 1999.
6588) However, although this method has a remarkable effect on preventing water absorption, the water repellent effect does not.
It is hard to say that it is fully satisfactory in the long term. Therefore, the inventors of the present invention further conducted intensive studies to maintain the water repellent effect stably over a long period of time in addition to the waterproof effect, and as a result, they arrived at the present invention.

That is, the gist of the present invention is that R2+0-8i expressed by the following formula (1) "-〇-R2(1) R2 (wherein R1 is a C4 to CI8 saturated alkyl group , R2 represents a saturated alkyl group of C1 to C9, and n represents an integer of 1 to 6.) Apply and impregnate an organic solvent solution of an organosilicon compound to prevent water absorption of the porous civil engineering and construction material, and then The following formula (II
) 3 II -%-0-S i→-0-H, (II ) (wherein R3 is a saturated alkyl group of C1 to CIFI, X is a hydroxyl group, a saturated alkyl group of C7 to CI8 or C3 〜C1 represents an alkoxy group, and m represents an integer of 7 to ■8.) Applying an organic solvent solution of a low polymer of an organosilicon compound,
A method for protecting porous civil engineering and construction materials, characterized by imparting water repellency to the civil engineering and construction materials.

In the present invention, the organosilicon compound used as the water absorption inhibitor is an organoalkoxysilane represented by the above-mentioned formula (I), an oligomer that is a low condensate thereof, and a mixture thereof. Whether these should be used alone or in combination, and the mixing ratio should be selected appropriately, taking into consideration the permeability, air permeability, and other properties of the various porous civil engineering and construction materials mentioned above. . If a high condensate having a higher degree of condensation than the oligomer is applied, the viscosity of the condensate will increase, resulting in poor permeability into the material, which is undesirable.

That is, by applying the compound represented by the general formula CI), a) the drug quickly penetrates deep into the material, (b) it reacts with the trace amount of moisture normally present in the material, and c) it penetrates from the surface of the material. Water repellency is imparted to the layer up to a certain depth, and 2) there is no scattering of chemicals into the atmosphere, resulting in water absorption with excellent weather resistance, alkali resistance, etc., without impairing the breathability of the material. A preventive layer can be formed.

Furthermore, a feature of the present invention is that an organic solvent solution of a low polymer of an organosilicon compound is applied to the above-mentioned material having a water absorption prevention effect of 1'#-, without impairing the air permeability of the material. Another objective is to impart water repellency without impairing the appearance.

As the organosilicon compound for imparting water repellency, 3 11-(-0-8i+-o-II (II) represented by the following general formula (n) (wherein R3 is a saturated alkyl group of C1 to CIFI) is used. group, X represents a hydroxyl group + a saturated alkyl group of CI to cps or an alkoxy group of C7 to C6, and m represents an integer of 7 to 18.) Low polymers of organosilicon compounds and mixtures thereof are used.

Regarding the degree of polymerization of the above-mentioned low polymer, if the degree of polymerization is too high, the air permeability of the material will be impaired, which is not desirable.

Furthermore, if the degree of polymerization is too low, it will penetrate too much into the interior, making it impossible to obtain the desired water-repellent effect, which is undesirable. Therefore, as the degree of polymerization, m=7 to 18 is preferably used.

By performing such treatment, the civil engineering and construction material will have both a thick water absorption prevention layer and a strong water repellent layer, making it possible to maintain more stable water repellency over a long period of time.

This makes it possible to prevent water from entering the material without damaging its appearance, as well as prevent dirt and dust from adhering to the material.
It can prevent the growth of mold, prevent efflorescence, and maintain the cosmetic properties of the material.

The compound represented by general formula (I) and the low polymer represented by general formula (n) used in the present invention are used after being dissolved in an organic solvent.

The organic solvent is not particularly limited as long as it dissolves these compounds uniformly, but examples of the former include ethanol, n-propatool, 1so-propatool, and tert-propatool. Alcohols such as butanol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol diethyl ether, tetrahydrofuran, 1
Ethers such as 4-dioxane, ketones such as acetone and methyl ethyl ketone, alkanes such as aliphatic naphtha and mineral spirits, toluene, xylene,
Aromatic hydrocarbons such as solvent naphtha and aromatic naphtha, and halogenated hydrocarbons such as trichlorethylene and perchlorethylene.

Esters such as ethyl acetate and mixtures thereof are included.

The concentration of the compound represented by the general formula (I) of the present invention in the above-mentioned organic solvent is preferably in the range of 2 to 20%, more preferably in the range of 3 to 10%, giving good results.

On the other hand, as the latter solvent, the former solvent can be used as is.

During construction, it is convenient if the solvent used is the same for both the former and the latter, but it does not have to be the same.

The concentration of the compound represented by general formula (II) in the organic solvent is usually in the range of ~10% for uniform dissolution.

In the case of low concentrations, the intended purpose can be achieved by applying multiple coats.

Alcohols usually used as solvents include ethanol, isopropanol, and ketones include acetone,
Methyl ethyl ketone, alkanes include mineral spirits and aliphatic naphtha.

As the aromatic hydrocarbons, toluene, xylene, solvent naphtha, and aromatic naphtha are preferably used.

Next, embodiments of the present invention will be described.

The porous civil engineering and construction materials can be coated by commonly used methods such as brush coating, roller coating, and spraying.

The amount of coating at that time varies depending on the material, but for undercoating to prevent water absorption, 10 to 1000 is applied in solution state.
g/m2 is a suitable amount. By doing this, the general formula (
The compound represented by I) reacts with moisture in the civil engineering and construction material, forming a thick water absorption prevention layer of 1 to 20 mm that is integrated with the material. Subsequently, a low polymer represented by the general formula (n) was added in solution for 1 hour for water-repellent finishing.
An overcoat of 0 to 500 g/m2 forms a layer with strong water repellency on the material.

As described in detail above, by carrying out the method of the present invention, it becomes possible to protect the civil engineering and construction materials from various problems caused by water, and as a result, the above-mentioned numerous excellent effects can be obtained. Can be done.

(Examples) The present invention will be explained in detail below using Examples, but the present invention is not limited by these in any way.

The measurement methods for the weather resistance test, water repellency, water absorption, and stain test in Examples are as follows.

Weather resistance test: The specimen is treated for 3000 hours using a sunshine weather meter according to JIS A-1415.

Regarding the specimen after treatment, the surface Test for water repellency and water absorption.

Surface water repellency: Place water droplets on the surface of the specimen and observe the condition of the water droplets.

○ It becomes a polka dot and rolls around.

△　　　　　　　　　　　There will be a little bit of adhesion.

×　　　There are no polka dots, and the mortar surface has a wet color.

Water absorption of pure water: The specimen is immersed in pure water to a depth of 5 cm, taken out after one week, immediately wiped off excess water on the surface with gauze, and measured its weight.

Water absorption amount (g) - Weight after immersion (g) - Weight before immersion (g
): Apply an appropriate amount of crayon (red) and ink (black) as contaminants to the surface of the specimen, then wash the crayon with thinner and the ink with neutral detergent and water, and test the degree of stain remaining. do.

○ No stains.

△ A little remains.

× Remain.

Stain test example-1 Mortar board (70X7) according to JIS A-6910
0x20mm) at 25°C and 65% RTI for several weeks, R+ in formula (1) is a methyl group, R
A 10% isopropanol solution of an organosilicon compound in which 2 is an ethyl group and n=1 was undercoated over the entire surface with a brush at a coating amount of 100 g/m2. After standing for 2 hours, a low polymer of an organosilicon compound in which R3 in formula (If) is a 1so-butyl group, X is a 1so-butyl group, and m = 15 to 17 is dissolved in isopropanol to a concentration of 5%. This solution was coated on the entire surface at a coating f of 150 g/m2, and this was applied once again in a constant temperature and humidity chamber at 25°C and 65% RI.
After curing for a week, it was used as a specimen. This specimen was tested for various performances shown in Table 1. The results are shown in Table.

Examples 2 to 5 Mortar board (70X7) according to JIS A-6910
0 x 20 mm) for one week at 25°C and 65% RII under constant temperature and humidity. Coating 1100g/m of a 10% solution of the solvent shown.
2, the entire surface was undercoated in the same manner as in Example 1, and left to dry for 2 hours.

Formula (n) having R', X, and m shown in Table 1
A low polymer of an organosilicon compound represented by the following was dissolved in a predetermined solvent to make a 5% solution, and the entire surface was overcoated at a coating amount of 50 g/m2. Repeat this once again at 25℃, 65% RI-
After being cured for one week in a constant temperature and humidity chamber (No. 1), it was used as a specimen.

This specimen was tested for various performances shown in Table 1.

The results are shown in Table-1.

Comparative Example-1 Using the same organosilicon compound represented by formula (1) as used in Example-1, the application amount of the isopropanol solution was 150 g/m2, and the organic silicon compound represented by formula (II) was used. Example except that the top coat of low polymer of silicon compound is not applied.
A specimen was prepared in the same manner as in 1. This specimen is shown in Table-1.
The various performances shown in the following were tested. The results are shown in Table-1.

(Collection of the Invention) The present invention relates to a method for protecting porous civil engineering and building materials, which prevents deterioration caused by water.

By implementing the present invention, porous civil engineering and construction materials will have both a thick water absorption prevention layer and a strong water repellent layer, and will last for a long time without impeding the material's breathability or changing its inherent appearance. Has stable water repellency, dust,
It prevents the adhesion of dust, mold, and efflorescence, resulting in excellent cosmetic properties.

Claims (6)

[Claims] (1) On the surface of porous civil engineering and construction materials, there are ▲mathematical formulas, chemical formulas, tables, etc. expressed by the following formula (I)▼(I) (wherein, R^1 is a saturated alkyl group of C_1 to C_1_8, R ^2 represents a saturated alkyl group of C_1 to C_5, and n
represents an integer from 1 to 6. ) An organic solvent solution of an organosilicon compound is applied and impregnated, and then expressed as the following formula (II) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (II) (In the formula, R^3 is the saturation of C_1 to C_1_8 The alkyl group,
Indicates an integer of 8. ) A method for protecting porous civil engineering and construction materials, characterized by applying an organic solvent solution of a low polymer of an organosilicon compound. (2) Compounds represented by general formula (I) and general formula (
The method according to claim 1, wherein the organic solvent in which the compound represented by II) is dissolved is selected from alcohols, ketones, alkanes, and aromatic hydrocarbons. (3) The method according to claim (2), wherein the alcohol is ethanol or isopropanol. (4) Claim in which the alkanes are mineral spirits (
2) The method described. (5) The method according to claim (2), wherein the aromatic hydrocarbon is a solvent naphtha. (6) Claim (1) wherein the concentration of the compound represented by general formula (I) in the organic solvent is 2 to 20%, and the concentration of the compound represented by general formula (II) is 1 to 10%. ) method described.