JPH0623314B2 - Rubber asphalt emulsion composition for spray waterproofing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a spray waterproofing method applied to a building or a construction for civil engineering, more specifically, a rubber asphalt emulsion and a polyvalent metal salt aqueous solution, respectively. Of the rubber asphalt emulsion composition used in the waterproofing method in which a rubber asphalt layer is formed on the adherend substrate surface by continuously spraying the emulsion and the polyvalent metal salt aqueous solution by contacting with each other.

[Problems to be Solved by Prior Art and Invention]

Conventionally, a method of spraying a rubber asphalt emulsion having a solid content of 50 to 80% by weight and a polyvalent metal salt aqueous solution simultaneously with separate spraying machines has been performed. However, in this case, when the rubber asphalt emulsion and the polyvalent metal salt aqueous solution are continuously contact-mixed to form the rubber asphalt layer on the adherend substrate surface, cracks or pinholes are generated due to the contraction of the rubber asphalt layer itself. Cheap. In order to prevent these cracks and pinholes from occurring as much as possible, it is necessary to make the base surface as smooth as possible and to make the spray angle perpendicular to the base surface. Even with such consideration, it is impossible to completely prevent the generation of cracks and pinholes, and it takes labor to repair these defective portions after spraying, which is rather complicated. If you try to reduce the amount of water separated by using an asphalt emulsion with a high solid content to reduce the shrinkage of the rubber asphalt layer itself, the formed rubber asphalt layer tends to become sponge-like,
It has the drawback of not being completely waterproof.

An object of the present invention is to provide a rubber asphalt emulsion composition that solves the above problems in the spray waterproofing method.

[Means for Solving the Problems]

In order to solve the above problems, the present inventor has conducted extensive research,
When the rubber asphalt emulsion used in the method is made to contain acicular calcium metasilicate (powder), the rubber asphalt emulsion composition and the polyvalent metal salt aqueous solution are sprayed by separate spraying machines to bring them into contact with each other. The inventors have found that when forming a rubber asphalt coating layer, phenomena such as cracks and pinholes in the rubber asphalt layer and formation of a porous coating layer do not occur, and have reached the present invention.

That is, the present invention provides a rubber asphalt emulsion for a spray waterproofing method, which comprises emulsifying asphalt with an anionic emulsifier and mixing it with rubber latex.
A rubber asphalt emulsion composition for a spray waterproofing method, characterized by containing acicular calcium metasilicate (powder) which passes through a 0 mesh sieve.

The rubber asphalt emulsion used in the present invention is usually prepared by mixing an anionic asphalt emulsion with rubber latex in an amount of 5 to 30% by weight. The anionic asphalt emulsion is obtained by emulsifying straight asphalt having a penetration of 40 to 200 with an anionic emulsifier such as potassium oleate and sodium alkylbenzene sulfonate. Types of rubber used for the rubber latex include natural rubber, synthetic rubber such as styrene-butadiene rubber, chloroprene rubber, and butadiene rubber.

The acicular calcium metasilicate compounded in such a rubber asphalt emulsion is represented by the chemical formula CaSiO ₃ and is generally known as wollastonite. It occurs naturally in the metamorphic limestone contact metamorphic belt. That is, CaCO ₃ + SiO ₃ → CaSi
Reaction of O ₃ + CO ₂ or Ca ₆ (Si ₆ O ₁₇ ) (O
H) ₂ (Zonotracite) obtained by decomposition by heating. The appearance has a short fibrous shape, and the crystal structure is needle-like or oblong.

The amount of acicular calcium metasilicate used in the present invention is 100% solids of rubber asphalt emulsion.
It is mixed in a proportion of 8 to 85 parts by weight, preferably 15 to 35 parts by weight, relative to parts by weight. Mixing is very easy and can be done by conventional stirring methods. In this case, if a 2 wt% aqueous solution of hydroxyethyl cellulose is further mixed in an amount of 8 parts by weight or more with respect to 100 parts by weight of the solid content of the rubber asphalt emulsion, acicular calcium metasilicate does not cause precipitation, and the rubber asphalt emulsion composition is obtained. The product exhibits very good storage stability.

When the amount of acicular calcium metasilicate used is 8 parts by weight or less, almost no effect such as crack prevention of the rubber asphalt layer formed after spraying is obtained, and when it is 85 parts by weight or more, the viscosity of the rubber asphalt emulsion composition increases. When sprayed, it does not become a mist, and contact mixing with the polyvalent metal salt aqueous solution becomes poor, and a good rubber asphalt layer cannot be obtained.

The acicular calcium metasilicate has a wide range of grades from those that do not pass through a 60 mesh sieve to those that pass through a 500 mesh sieve, but the acicular calcium metasilicate used in the present invention passes through a 60 mesh sieve. Must be one, preferably 6
A grade having a grade that passes through a 0 mesh sieve and does not pass through a 100 mesh sieve is preferable. Those that do not pass through the 60-mesh sieve are likely to be clogged with the nozzle tip of the sprayer, and the effect decreases when the number that passes through the 100-mesh sieve increases.

For the time being, asbestos, sepiolite,
Although it is possible to mix each fiber such as vinylon, polyester, nylon, glass, etc., even if a small amount of asbestos or piolite is mixed, the viscosity of the rubber asphalt emulsion is remarkably increased, so that it cannot be actually used. In particular, asbestos is cationic, so that when it is mixed with an anionic emulsion, it has a function of destroying and coagulating the emulsion. Synthetic fibers such as vinylon, polyester and nylon also increase the viscosity of the rubber asphalt emulsion considerably, so that it is not preferable to use them. Since glass fiber also dissolves in the anionic asphalt emulsion, it impairs storage stability and cannot be used. Also, potassium titanate,
Whiskers such as silicon carbide and zinc oxide are effective to some extent, but if they are mixed to such an extent that they are effective, they become very expensive and not economical. Contrary to this, the acicular calcium metasilicate, unlike the fibrous substance, acts extremely effectively. As the polyvalent metal salt aqueous solution,
A 1-10 wt% aqueous solution of calcium chloride, calcium nitrate, alum, etc. is used. The ratio of the rubber asphalt emulsion composition and the polyvalent metal salt aqueous solution at the time of spraying is generally 3 to 8: 1 by weight.

The spraying machine can be either an air spraying machine or an airless spraying machine which is generally used and is not particularly limited.

[Action]

The rubber asphalt emulsion composition of the present invention is a rubber asphalt emulsion in which acicular calcium metasilicate is randomly mixed, and is continuously contacted with a polyvalent metal salt aqueous solution sprayed from a separate spraying machine when spraying. Upon mixing, the rubber asphalt emulsion composition is destroyed by the action of the polyvalent metal salt to form a rubber asphalt layer while dehydrating. In this case, the acicular calcium metasilicate contained in the rubber asphalt layer is fibrous, and there is no defect due to other fibrous substances as described above, and the function of suppressing shrinkage is exerted as a reinforcing material of the rubber asphalt layer. The generation of cracks and pinholes is reliably prevented.

〔Example〕

Hereinafter, examples and comparative examples will be described. in this case,
Examples of various additives and various amounts of the additives to the rubber asphalt emulsion are given, and the performance evaluations thereof are shown in the table.

Example 1 A container having a capacity of 20 was charged with anionic asphalt emulsion (solid content: 60% by weight) and 8.5 kg, and styrene-butadiene rubber latex (solid content: 60% by weight) (1.5 kg) was added. K. A rubber asphalt emulsion was prepared by stirring and mixing with a homodisper (stirrer manufactured by Tokushu Kika Kogyo Co., Ltd.) at a low speed rotation of 300 rpm for 10 minutes. 10 kg of this rubber asphalt emulsion was mixed with needle-like calcium metasilicate (100 mesh passed through a 60 mesh sieve to obtain 100
0.5 kg of powder that does not pass through the mesh sieve)
K. 15 with a homodisper at 700 rpm
Stir for 1 minute and mix until homogeneous. Then, 0.5 kg of a 2 wt% aqueous solution of hydroxyethyl cellulose
The rubber asphalt emulsion composition could be obtained by adding and stirring for 5 minutes.

Examples 2 to 5 Rubber asphalt emulsion compositions having the compositions shown in the table were obtained in the same manner as in Example 1.

Comparative Examples 1 to 8 Rubber asphalt emulsion compositions were prepared in the same manner as in the examples, except that the compositions shown in the table were outside the scope of the present invention.

Performance evaluation method: (1) Storage stability The prepared sample is left to stand at 20 ° C. for 120 hours, and the presence or absence of solidification of the emulsion composition is visually observed. Those that did not solidify were considered good, and those that solidified were poor.

(2) Sprayability Of the samples after the storage stability test, only good samples that do not solidify were airless sprayer Vicount II4500 (pressure ratio 3: 1, maximum discharge 12 with hydraulically driven plunger pump). / Min made by Nippon Gray Co., Ltd.) and sprayed in a mist state, and 5% by weight of calcium chloride by individual spraying machine
Aqueous solution is sprayed at the same time. In this case, the slate plate is the surface to be adhered, the tip of the nozzle of the spraying machine is at a distance of about 60 cm from the slate plate surface, and until the sample of the rubber asphalt emulsion composition and the calcium chloride aqueous solution reach the slate plate surface. The direction of the nozzle is adjusted so that the space and the surface of the slate plate can be continuously contact-mixed. The weight ratio of the sample to the calcium chloride aqueous solution was 5: 1.

The evaluation of spraying performance is performed by visually observing the situation in which the spraying is used in the form of mist in the spraying step described above, and the solution is continuously in contact with and mixed with the calcium chloride aqueous solution. A sample that was normally atomized and an aqueous solution of calcium chloride was continuously in contact and mixed was rated as good, and a sample that was not atomized normally or caused nozzle clogging was rated as poor.

(3) Appearance of coating layer A rubber asphalt layer is formed on the surface of the slate plate in the sprayability test, but the rubber asphalt layer immediately cracks,
Observe the occurrence of pinholes. Those that did not generate these were regarded as good, and those that occurred were regarded as defective.

[Effects of the Invention] According to the present invention, by mixing a specific grade of acicular calcium metasilicate to a rubber asphalt emulsion, preferably in a specific amount, spraying with a spraying machine can be carried out without any trouble, And the rubber asphalt layer that is formed does not have cracks, pinholes and sponge-like formation, and an excellent waterproof layer can be easily formed, and there is no labor required for repairing.
The effect is extremely large.

Claims (2)

[Claims] 1. A rubber asphalt emulsion for a spray waterproofing method prepared by emulsifying asphalt with an anionic emulsifier and mixing it with a rubber latex, wherein a needle-like calcium metasilicate powder passing through a 60 mesh sieve is contained. A rubber asphalt emulsion composition for a spray waterproofing method, characterized by: 2. The acicular calcium metasilicate having a particle size of 6
The rubber asphalt emulsion composition according to claim 1, which is in a range that passes through a 0 mesh sieve and does not pass through a 100 mesh sieve, and contains 8 to 85 parts by weight based on 100 parts by weight of the solid content of the rubber asphalt emulsion. object.