JPS6228241B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for forming a ridge that is highly waterproof.

Conventional furrows were prevented from leaking by applying cultivated soil mixed with water to the slope, but this method did not have a sufficient waterproofing effect. For this reason, measures to prevent water leakage were taken, such as forming the ridge with concrete or laying a waterproof sheet over the ridge forming part, but both methods were extremely difficult to work with and significantly increased the cost of ridge forming. .

In view of the above circumstances, the present invention provides a ridge forming method that can efficiently form a highly waterproof ridge at low cost, and will be described below.

The ridge forming method according to the present invention scrapes the slope of the ridge that has been formed in advance to expose a new surface layer, and also excavates the area just below the slope to form a groove along the ridge. After applying a blended composition containing a polyvinyl alcohol resin, a water-insoluble polyisocyanate, and water as essential components to the exposed new surface and the slope side wall of the formed groove, excavation is performed at the time of forming the groove. It is characterized by refilling the trench with soil. Hereinafter, the present invention will be explained based on drawings showing embodiments.

Since furrows separate fields from one another, they are usually maintained for many years without being demolished. In the ridge forming method according to the present invention, first, as shown in FIG. A groove 3 along the ridge 1 is formed in this part. The depth of the groove 3 is preferably equal to or deeper than the plowing depth D, but may be shallower than this depending on the case. At this time, the soil 6 scraped from the slope 2 and the soil 6 excavated to form the groove 3 may be piled up on the upper edge of the inner side of the groove (on the opposite side from the ridge). Next, the slope of the furrow where the old topsoil has been scraped away 2
Then, a blended composition containing a polyvinyl alcohol resin, a water-insoluble polyisocyanate, and water as essential components is applied to the side wall 4 of the groove 3, which is an extension of the slope.

The polyvinyl alcohol resin is a saponified product of a polymer whose main component is vinyl acetate,
Any water-soluble resin can be used, but among them, so-called partially saponified polyvinyl alcohol resins with a degree of polymerization of 300 or more and a degree of saponification of 95 mol% or less are suitable for improving liquid stability, gelling properties, It is preferable in terms of solubility and the like. carboxyl group, sulfone group,
Aldehyde,
So-called post-modified polyvinyl alcohol resins obtained by reacting acid anhydrides, vinyl monomers, etc. can also be used. If the degree of polymerization of the polyvinyl alcohol resin is lower than 300, the gelling efficiency will decrease and a large amount of polyisocyanate will be required, which is economically undesirable. The degree of saponification of polyvinyl alcohol resin varies depending on the degree of modification, but generally the degree of saponification is 95 mol%.
If it is larger than this, it becomes difficult to emulsify, and the solubility in water at room temperature decreases, which impairs on-site workability, which is not preferable. Note that an aqueous emulsion containing a polyvinyl alcohol resin can also be used.

Water-insoluble polyisocyanates include aromatic diisocyanates such as m- and p-phenylene diisocyanate, 4-tert-butyl-m-phenylene diisocyanate, 2,4- and 2,
6-Toluene diisocyanate, m- and p-
Xylene diisocyanate, diphenylmethane
4,4'-diisocyanate, dianisidine diisocyanate, polymethylene polyphenyl isocyanates, toluene-2,4,6-triisocyanate, diphenyl-2,4,4'-triisocyanate, triphenylmethane-4,4'. 4″-triisocyanates and aliphatic diisocyanates,
Many isocyanate compounds are included, such as hexamethylene diisocyanate, decamethylene diisocyanate, and alicyclic polyisocyanates such as hydrogenated methylene diisocyanate and isophorone diisocyanate. Preferably, diphenylmethane diisocyanate and polymethylene polyphenyl isocyanates are used.

A catalyst that promotes or inhibits the reaction of isocyanate, such as an organic tin compound, a basic compound, or an acidic compound, may be added as appropriate. When using crude diphenylmethane diisocyanate as the water-insoluble polyisocyanate, it is better to use hexametaphosphoric acid in combination to keep the PH of the composition on the acidic side, which will take a longer time to gel and give more room for on-site workability. , which is generally convenient.

The concentration of the polyvinyl alcohol resin contained in the compounded composition used in the present invention should be appropriately selected depending on the purpose of use, the concentration of other additives, etc., but is usually in the range of 0.5 to 20% by weight. It is appropriate to select from 2 to 10% by weight, and more preferably from 2 to 10% by weight.

In the present invention, the amount of water-insoluble polyisocyanate contained in the gelling composition is generally 1% to the amount of polyvinyl alcohol resin present.
A range of ~1000% by weight is suitable, preferably 10
It is safe to choose from the range of ~100% by weight.

Next, in order to maintain a desirable dispersion state of the water-insoluble polyisocyanate in the above-mentioned blended composition, it is desirable to increase the viscosity of the system to some extent. For this purpose, a thickener,
It is effective to add fillers and the like as necessary. Examples of thickeners include methyl cellulose, carboxymethyl cellulose, methyl vinyl ether, polyacrylamide, and polyethylene oxide. In addition, as fillers, clay, calcium carbonate, silicon oxide, gypsum,
Perlite etc. can be used. To improve the dispersion state of polyisocyanate,
It is also effective to constantly stir the system, use a polyvinyl alcohol resin with strong emulsifying power, and add a small amount of emulsifier.

Since furrows are often destroyed by small animals such as moles and rats, it is preferable to add a repellent for these harmful small animals to the above-mentioned compounded composition. Repellents used for this purpose include, for example, cycloheximide. Instead of adding such a repellent for harmful small animals to the above compounded composition, this repellent may be applied separately before or after applying the above compounded composition to the slope of the furrow, etc.

The blended composition may be applied by any method, but spraying is preferred as it is efficient. By this application, a waterproof layer 5 of the compounded composition is formed on the slope 2 of the furrow and the side wall 4 of the groove 3 following the slope, as shown in FIG. Once this waterproof layer 5 is formed, the trench 3 is refilled with the soil that was previously scraped off from the slope and the soil that was excavated during trench formation. As a result, a highly waterproof ridge 1' can be obtained as shown in FIG.

In addition, in the above explanation, an example was explained in which a conventional ridge that has been formed in advance is used. After applying the compounded composition to the slope surface and the side walls of the groove in the same way,
A similar waterproof ridge can be obtained by filling the grooves. In this case, there is no need to cut down the slope of the ridge.

The method of forming a highly waterproof furrow according to the present invention involves scraping off the topsoil of the slope of the furrow that has been formed in advance, and digging up the soil directly below the slope to form a groove. This method is extremely efficient because it is only necessary to refill the groove after applying the compounded composition to the side wall on the ridge side of the groove and the slope. Due to the composition containing polyvinyl alcohol resin, water-insoluble polyisocyanate, and water as essential components, a waterproof coating with excellent waterproofness and durability is formed on the sides of the ridge, making the resulting ridge waterproof. It becomes sexual. Since the waterproof layer formed on the lower side of the slope of the furrow is embedded within the soil, water leakage from this area is also effectively prevented. It is less expensive than conventional concrete ridges, has no seams like conventional ridge sheets, has excellent waterproofing effects, and does not impair its aesthetic appearance.

If the above-mentioned compounded composition is used in combination with a repellent for harmful small animals such as rats and moles, it will be even better in preventing water leakage.

[Brief explanation of the drawing]

1, 2, and 3 are cross-sectional views showing the steps of the ridge forming method according to the present invention. All figures relate to embodiments. 1...furrow, 2...slope, 3...groove, 4...side wall, 5...waterproof layer.

Claims (1)

[Claims] 1. The slope of the ridge that has been formed in advance is scraped to expose a new surface layer, and the area directly below the slope is excavated to form a groove along the ridge. After applying a composition containing a polyvinyl alcohol resin, a water-insoluble polyisocyanate, and water as essential components to the new surface and the slope side wall of the formed groove, the soil excavated during the groove formation is applied. A highly waterproof ridge forming method characterized by refilling the grooves. 2. The method for forming a highly waterproof ridge according to claim 1, wherein the compounded composition contains a repellent for harmful small animals such as moles and rats.