Nitto Chemical Industry Co., Ltd.

Yamaguchi Kikai Kogyo Co., Ltd.

Nihon Sogo-bosui Co., Ltd.

Nihon Soil Engineering Co., Ltd.

Shunsuke Tazawa

Kenji Takeuchi

Katsuhiko Kurihara

Mineo Murata

Mitsuji Ishida

Kazuo Okabe

Kazuhiko Kon

Akiyoshi Horiba

Syouichi Kashima

Mitsuaki Abe

Seinosuke Ando

Yuzuru Kawagoe

A process for producing an inorganic compound-containing urea resin, which comprises adding an acidic gelling agent to an aqueous urea-formaldehyde precondensate solution to prepare a urea resin-containing product, and either

Process for producing inorganic compound-containing urea resin

An improved grout impregnation method which uses an injection tube for contacting and mixing different kinds of materials supplied thereinto separately to prepare a grout and impregnates the grout into the earth through an injecting opening provided at a tip end of the tube. In this method, a first pressure-holding valve is provided within a higher-pressure path for one of the materials which is supplied under a higher pressure, a mixing section is provided downstream the first pressure-holding valve but in the vicinity thereof for contacting and mixing said one of the materials with another one which is supplied under a lower pressure, and a second pressure-holding valve is provided downstream the mixing section; said one of the materials is passed through the first pressure-holding valve, which reduces the pressure of said one of the materials, and then contacted and mixed with said another one at the mixing section; the contacting and mixing is carried out under a pressure exceeding an atmospheric pressure and determined by the second pressure-holding valve; and the grout resulting from the contacting and mixing and passing through the second pressure-holding valve is impregnated into the earth through the injection opening.

Grout impregnation method

A slow release nitrogen fertilizer comprising a hydrous cured product of urea-formaldehyde condensate in which the total methylol content is 0.1 to 1.0% by weight (based on the weight of hydrous product) and the hot water-dissolution percentage [percentage of the cured product dissolved in hot water at 80.degree. C. when the product has been immersed therein for 30 minutes (based on the weight of anhydrous product)] is 10% by weight or less.

Urea-formaldehyde condensate-based slow release nitrogen fertilizer and

In the stabilization of soil which comprises injecting into soil a mixture of (A) an aqueous sodium silicate solution and (B) at least one compound selected from the group consisting of chlorides, sulfates and nitrates of aluminum, magnesium and iron, and then gelling the injected mixture in soil, the formation of a large amount of the metal hydroxide precipitate on mixing the components (A) and (B) can be prevented by adding (C) at least one oxy acid selected from the group consisting of citric acid, tartaric acid and lactic acid to any one of the components (A) and (B).

Process for stabilizing soil

Growing community of inventors

Tokyo, Japan

Shunsuke Tazawa