Method for producing soil solidification composition and soil solidification method

Abstract

To provide a manufacturing method of a soil solidification composition capable of manufacturing easily the highly-strong soil solidification composition.SOLUTION: There is provided a manufacturing method of a soil solidification composition including emulsion containing cation polymer, anion polymer and salt. The manufacturing method of the soil solidification composition has a step of adding the anion polymer to the salt in the presence of water, and further preferably has a step of adding the emulsion, after the step of adding the anion polymer to the salt.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a method for producing a soil solidification composition and a soil solidification method. [Background technology]

[0002] At construction sites, when building structures below ground level, earthworks are often carried out, which involve digging up soil and moving it to another location. In earthworks, intermediate steps include leveling the ground and creating slopes (artificial slopes).

[0003] If flat ground or slopes are left as they are, the ground surface will be exposed to the wind, causing the soil to turn into dust and fly away.Furthermore, the ground surface will be eroded by rain, causing it to melt and soil to flow out. To prevent soil erosion, measures have been taken, such as sprinkling water on flat ground or slopes, or covering them with sheets, but these methods must be repeated many times during the construction period, which increases costs.

[0004] Therefore, instead of watering or covering with a sheet, chemicals have been proposed to stabilize the ground surface. One of these is a soil solidification composition that uses a polyion complex obtained by reacting an anionic polymer and a cationic polymer (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2019-056075 Summary of the Invention [Problem to be solved by the invention]

[0006] When preparing a polyion complex (PIC) from an anionic polymer and a cationic polymer, it is necessary to prepare an anionic polymer solution and a cationic polymer solution, respectively. However, anionic polymers and cationic polymers are poorly soluble in water, which makes it time-consuming to prepare the solutions and makes them difficult to use on-site.

[0007] To address this issue, one possible method is to prepare PIC using water-soluble anionic and cationic polymers, but it has been difficult to obtain a soil solidification composition with sufficient strength to solidify the soil.

[0008] An object of the present invention is to provide a method for producing a soil solidification composition that can easily produce a soil solidification composition having high strength. [Means for solving the problem]

[0009] The present inventors considered that the state in which the cationic polymer is added is important for producing a soil solidification composition in a short time, and focused on the cationic polymer. As a result of further investigation, the inventors have found that by using a cationic polymer in an emulsion state, a soil solidification composition containing PIC as the main component can be efficiently prepared, and that the PIC can also have sufficient strength.

[0010] Specifically, one embodiment of the present invention is a method for producing a soil solidification composition comprising an emulsion containing a cationic polymer, an anionic polymer, and a salt, the method comprising: adding the anionic polymer to the salt in the presence of water. [Effects of the Invention]

[0011] According to the present invention, a method for producing a soil solidification composition can be provided, which can easily produce a soil solidification composition having high strength. DETAILED DESCRIPTION OF THE INVENTION

[0012] (Method for producing soil solidification composition) The method for producing a soil solidification composition of the present invention preferably includes a step of adding an anionic polymer to salt, and after the step of adding the anionic polymer to the salt, a step of adding an emulsion containing a cationic polymer, and further includes other steps as necessary.

[0013] The step of adding the anionic polymer to the salt is carried out in the presence of water. Specifically, the salt is dissolved in water to prepare an aqueous solution of the salt, and the anionic polymer is added to the aqueous solution of the salt. The anionic polymer can be dissolved by adding the anionic polymer to a solution in which a salt has been dissolved.

[0014] The step of adding an emulsion containing a cationic polymer is a step of adding an emulsion containing a cationic polymer to a solution in which a salt and an anionic polymer have been dissolved. Through this step, the anionic polymer and the cationic polymer react with each other to produce PIC.

[0015] The step of adding the emulsion containing the cationic polymer may be carried out before or after preparing the aqueous salt solution, but it is preferable to add the emulsion to the anionic polymer solution, as this allows the solubility of the anionic polymer, which will be described later, to be visually confirmed in the production of the soil solidification composition. That is, it is preferable to dissolve the salt in water, add and dissolve the anionic polymer therein, and then add an emulsion of the cationic polymer to react with the anionic polymer.

[0016] <Water> The water is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include tap water, distilled water, etc. These may be used alone or in combination of two or more.

[0017] <Anionic polymer> The anionic polymer is not particularly limited as long as it forms a complex with the cationic polymer described below, and can be appropriately selected depending on the purpose. It may be one extracted and produced from a natural product, or one appropriately synthesized. Specific examples of anionic polymers include carboxymethyl cellulose, carboxymethyl amylose, carboxymethylated starch, lignosulfonic acid and its salts, (poly)acrylic acid and its salts, and polysulfonic acid and its salts. These may be used alone or in combination of two or more. The anionic polymer may be either a synthetic one or a commercially available product, such as Sunrose CS2 (carboxymethyl cellulose, manufactured by Nippon Paper Industries Co., Ltd.).

[0018] The shape of the anionic polymer is not particularly limited and can be appropriately selected depending on the purpose, but from the viewpoint of solubility in water, it is preferably in the form of granules.

[0019] <Emulsion containing cationic polymer> An emulsion containing a cationic polymer is a dispersion of the cationic polymer in a liquid. The cationic polymer is in the form of particles in the liquid. The liquid in which the cationic polymer is dispersed is not particularly limited and can be appropriately selected depending on the purpose, but it is preferable that the liquid contains water.

[0020] The cationic polymer can be selected appropriately depending on the purpose, as long as it forms a complex with the anionic polymer. It can be extracted or produced from natural products or synthesized. Specific examples of cationic polymers include dicyandiamide-formaldehyde resin, diethylenetriamine-dicyandiamide-ammonium chloride condensate, (meth)acryloyloxyalkyltrialkylammonium chloride polymer, dimethyldiallylammonium chloride polymer, ethyleneimine polymer, diallylamine polymer, ammonia-epichlorohydrin-dimethylamine copolymer, polyacrylamide resin, polymethacrylate resin, polyacrylate resin, and cationic cellulose. These polymers can be used alone or in combination.

[0021] The emulsion containing the cationic polymer may be either a synthetic one or a commercially available product, such as Aronflock E3380 (manufactured by MT Aquapolymer Co., Ltd.).

[0022] <Salt> A salt is a compound in which a cation and an anion are ionic bonded, and refers to a salt in the broad sense. Examples of salts include inorganic salts and organic salts, with inorganic salts being preferred. The inorganic salt is not particularly limited and can be appropriately selected depending on the purpose, but ammonium sulfate is preferred because it is superior in the following respects. The soil solidification composition of the present invention has excellent dispersion stability -Excellent solubility with anionic polymer (carboxymethyl cellulose) components It is generally used as a fertilizer, and even when spread on soil, it places little burden on the environment. In addition, after spreading, the soil becomes suitable for vegetation (especially grass, etc.).

[0023] The mass ratio of the anionic polymer to the cationic polymer is not particularly limited and can be appropriately selected depending on the purpose, but an anionic polymer:cationic polymer ratio of 2:1 to 1:1 is preferred.

[0024] The soil solidification composition may contain other components in addition to PIC. The other components are not particularly limited as long as they do not impair the effects of the present invention, and can be selected appropriately depending on the purpose.

[0025] (Soil solidification method) In the soil solidification method of the present invention, the soil solidification composition is applied to the target soil, and then water is additionally applied. Other methods may be added as needed. The soil solidification composition may be a soil solidification composition produced by the above-mentioned soil solidification composition. The other methods are not particularly limited as long as they do not impair the effects of the present invention, and can be appropriately selected depending on the purpose.

[0026] An example of the soil solidification method will be specifically described below. First, a solution containing the soil solidification composition PIC (PIC solution) is sprayed onto the target ground in the same manner as when watering. The soil solidification composition forms a strong adhesive layer of soil particles. Next, additional water is sprayed (sprinkled). Sprinkling water is preferable because it reduces the salt concentration and allows for the formation of a stronger soil particle adhesive layer. This is because the polymer becomes less soluble in water, preventing the formation of turbid water with poor settling properties, and also improving the durability of the adhesive layer. [Example]

[0027] Examples of the disclosed technology will be described below, but the disclosed technology is not limited to these examples.

[0028] In the examples shown below, the PIC concentration was 1.0%, and the cationic polymer / anionic polymer ratio was 1 / 4 (mass ratio) and 1 / 2 (ion equivalent).

[0029] Example 1 A 2-liter glass container was charged with 990 g of tap water and 19.8 g of ammonium sulfate, dissolved, and stirred for 5 minutes at 300 rpm using a stirrer (Three-One Motor Stirrer, manufactured by Shinto Scientific Co., Ltd.) to obtain a 2.0 mass% aqueous ammonium sulfate solution. Eight grams of an anionic polymer (Sunrose CS2, manufactured by Nippon Paper Industries Co., Ltd.) was added to the resulting aqueous ammonium sulfate solution, and the mixture was stirred for 10 minutes at 300 rpm using a stirrer (Three-One Motor Stirrer, manufactured by Shinto Scientific Co., Ltd.). Thereafter, 5.19 g of an emulsion containing a cationic polymer (Aronflock E3380, manufactured by MT Aquapolymer Co., Ltd.) was added and stirred at 300 rpm for 10 minutes to obtain the soil solidification composition (PIC) of Example 1. The stirring was continued until the PIC obtained by the reaction between the anionic polymer and the cationic polymer became dispersed. It took 25 minutes for the PIC to become dispersed.

[0030] Example 2 A 2-liter glass container was charged with 990 g of tap water and 19.8 g of ammonium sulfate, dissolved, and stirred for 5 minutes at 300 rpm using a stirrer (Three-One Motor Stirrer, manufactured by Shinto Scientific Co., Ltd.) to obtain a 2.0 mass% aqueous ammonium sulfate solution. 5.19 g of an emulsion containing a cationic polymer (Aronflock E3380, manufactured by MT Aquapolymer Co., Ltd.) was added to the resulting aqueous ammonium sulfate solution, and the mixture was stirred for 10 minutes at 300 rpm using a stirrer (Three-One Motor Stirrer, manufactured by Shinto Scientific Co., Ltd.). Thereafter, 8 g of anionic polymer (Sunrose CS2, manufactured by Nippon Paper Industries Co., Ltd.) was added and stirred at 300 rpm for 15 minutes to obtain the soil solidification composition (PIC) of Example 2. The stirring was continued until the PIC obtained by the reaction between the anionic polymer and the cationic polymer became dispersed. It took 30 minutes for the PIC to become dispersed.

[0031] Example 3 990 g of tap water and 5.19 g of an emulsion containing a cationic polymer (Aronflock E3380, manufactured by MT Aquapolymer Co., Ltd.) were placed in a 2 L glass container and stirred at 300 rpm for 10 minutes using a stirrer (Three-One Motor Stirrer, manufactured by Shinto Scientific Co., Ltd.). Then, 19.8 g of ammonium sulfate was added and dissolved, and the mixture was stirred for 5 minutes at 300 rpm using a stirrer (Three-One Motor Stirrer, manufactured by Shinto Scientific Co., Ltd.). 8 g of anionic polymer (Sunrose CS2, manufactured by Nippon Paper Industries Co., Ltd.) was added, and the mixture was stirred for 15 minutes at 300 rpm to obtain the soil solidification composition (PIC) of Example 3. Stirring was continued until the PIC obtained by the reaction between the anionic polymer and the cationic polymer became dispersed. It took 30 minutes for the PIC to become dispersed.

[0032] (Comparative Example 1) In a 2 L glass container, 990 g of tap water and 4.15 g of cationic polymer (Aronflock C303, manufactured by MT Aquapolymer Co., Ltd.) were placed and dissolved, and then 4.2 g of ammonium sulfate was added to obtain an aqueous cationic polymer solution. Into another 2 L glass container, 35.8 g of ammonium sulfate was added to 990 g of tap water, and after dissolution, 15.9 g of anionic polymer (Sunrose CS2, manufactured by Nippon Paper Industries Co., Ltd.) was added to obtain an aqueous anionic polymer solution.

[0033] While stirring the resulting anionic polymer aqueous solution, the cationic polymer aqueous solution was quantitatively supplied by a tube pump to react the anionic polymer with the cationic polymer, thereby obtaining a soil solidification composition (PIC) of Comparative Example 1. The stirring was continued until the PIC obtained by the reaction of the anionic polymer with the cationic polymer became dispersed. It took 65 minutes for the PIC to become dispersed.

[0034] <Measurement of bearing strength> The resulting soil solidification composition was evaluated based on bearing strength. The evaluation results are shown in Table 1. Silica sand No. 7 (Mizunami) was used as the sample soil. Approximately 4,000 g of sample soil was placed in a 312 mm x 237 mm x (height) 49 mm (surface area: 0.074 m 2 ) and spread it in a container. Each PIC solution is 2L / m 2 The mixture was then left to cure at room temperature of 22°C for one week. After curing, the penetration resistance was measured using a push cone (manufactured by Daiki Rika Kogyo Co., Ltd.) and converted into bearing strength based on the conversion table attached to the push cone. Note that when PIC solution was not sprayed, the penetration resistance was 0 mm.

[0035] [Table 1]

[0036] In Comparative Example 1, which is a conventional method, the PIC fabrication time was 65 minutes, whereas in Examples 1 to 3, which are the manufacturing methods of the present invention, the PIC fabrication time was approximately 30 minutes. This result demonstrates that the manufacturing methods of the present invention allow fabrication in a short time. Furthermore, while two containers are required to prepare the PIC in Comparative Example 1, the PIC can be prepared in one container in Examples 1 to 3. That is, the soil solidification composition can be synthesized in one pot by the method for producing a soil solidification composition of the present invention.

[0037] Furthermore, in the preparation of PIC in Examples 2 and 3, compared to Example 1, the solutions were cloudy, making it difficult to see how the anionic polymer was dissolving. Therefore, the method of dissolving the anionic polymer and then dispersing the emulsion containing the cationic polymer can shorten the preparation time and also allows the preparation to be carried out while checking the state of the solution.

[0038] The results of the support strength showed that the PIC produced by the production method of the present invention had higher support strength than the PIC produced by the conventional method in Comparative Example 1. These results clearly show that the PIC produced by the production method of the present invention has improved strength compared to the conventional PIC.

[0039] From the above, it has become clear that the soil solidifying composition produced by the method for producing a soil solidifying composition of the present invention can be produced in a short time and has high strength.

Claims

1. A method for producing a soil solidification composition comprising an emulsion containing a cationic polymer, an anionic polymer, and a salt, the method comprising: A method for producing a soil solidification composition, comprising the step of adding the anionic polymer to the salt in the presence of water.

2. 2. The method for producing a soil solidifying composition according to claim 1, further comprising the step of adding the emulsion after the step of adding the anionic polymer to the salt.

3. The method for producing a soil solidifying composition according to claim 1 or 2, wherein the anionic polymer is in a granular form.

4. The method for producing a soil solidification composition according to any one of claims 1 to 3, wherein the salt is ammonium sulfate.

5. A soil solidification method comprising spraying a soil solidification composition obtained by the method for producing a soil solidification composition according to any one of claims 1 to 4 onto target soil, and then additionally spraying water.