JPS59157174A - Water-stopping method using polyacrylic acid - Google Patents

Abstract

PURPOSE:To achieve a water-stopping work without causing toxicity problems, by preparing a principal agent composed mainly of acrylic acid and an assistant containing an oxidizing agent and a neutralizing agent, and mixing the principal agent with the assistant in site, thereby forming a water-insoluble polymer of sodium acrylate in the soil. CONSTITUTION:(A) A principal agent is prepared by adding preferably 0.1-0.9% (based on 100% of the formed gel) of a crosslinking agent such as N,N'-ethylene glycol diacrylamide, etc. to an aqueous solution containing about 50% of acrylic acid, and then dissolving preferably 1-5% of triethanolamine in the mixture as an accelerator, and separately, (B) an aqueous solution of an assistant containing preferably 0.1-10% of an oxidizing agent such as ammonium persulfate and an alkali (e.g. KOH) necessary to neutralize almost all acrylic acid, is prepared beforehand. The principal agent A is mixed with the assistant B in site to form a water-insoluble polymer of sodium acrylate in the soil and to achieve the water-stopping.

Description

[Detailed description of the invention]! ! Sodium silicate, lignins, urethane N fats, urine 51e & fats, polyacrylamide, etc. have been conventionally used as water stoppage construction methods using (I + 8 liquid), but each method causes environmental pollution due to the elution of alkalis and harmful substances. As a result, strict administrative guidance such as prohibition of use is currently in place. -The silicate-based water stop method has weaknesses in alkali elution and durability, but there is no alternative, and its use has been provisionally approved.

Lignin has low strength and durability, and is particularly susceptible to decay and decomposition. In addition, in the case of urethane and urea 2MM resin systems, the presence of raw materials such as isocyanates, amines, formalin, etc. is an obstacle, and even in the construction using the water stop method, toxic gases, strong odors, and tool stains are strong. It is difficult to remove due to its unique viscosity, which causes problems such as problems due to poor mixing, and is also disadvantageous in terms of economy.

On the other hand, acrylamide resin can easily suppress gelation time compared to other resins. ! The viscosity of the clay is low, it mixes well, and has good permeability into the soil, and the formed hydrous gel of polyacrylamite is water resistant, insoluble, and has sufficient strength and durability.

However, the raw material of acrylamide is so morphological that it is designated as a deleterious substance for medical and non-medical use, and there is a risk of contaminating the groundwater system if the construction is inadequate.

The present invention was researched with the aim of solving the dramatic effects of acrylamide resin, and by using acrylic acid, which is approved as a food additive, as its main raw material, it was possible to obtain a gel compound suitable for use.

Acrylic acid is a colorless transparent liquid that emits a characteristic sour odor and freezes in cold weather, so it is appropriate to use it as a melting agent at around 50%, and the viscosity is low without any problems.

N,N' ethylene glycol thiacrylamide is '0.
Requires addition of 1 to 0.9%. Similar to this crosslinking agent, methylenebisacrylamide and methylolacrylamide may also be used. Since these compounds do not cause strong ml-induced coma like acrylamide alone, and the amount added is within 1%, the possibility that they will elute as unreacted substances is close to zero.

Although triethanolamine is also a safe drug, trimethylaminopropionitrile, which is used for the same purpose, has jH properties, so triethanolamine is suitable.

The addition amount is preferably 1 to 5%. Ferrous sulfate can also be used as a substitute for triethanolamine.

Immediately before use, these η5 agents have an acrylic acid concentration of 5 to 15% (the mixing ratio of main agent:auxiliary agent is 1:1, so the concentration in the main agent is 10 to 30%).

All percentages are based on the content of 100% gel. ). In this case, soft or hard gel can be selected depending on the concentration of acrylic acid, but a gel with a stable diameter of 8% is obtained. If the amount of crosslinking agent is reduced, the viscosity increases, and ultimately the viscosity remains.

On the other hand, ammonium persulfate is used as an auxiliary agent in an amount of 0.1 to 10%, and the gelation time is determined by its 111.

- In the water stop method, 20 seconds to 300 seconds is appropriate depending on the case.

Other alkalis can be used as the caustic soda required for neutralization, and if calcium is used in part, a large gel with special water resistance flE can be formed. The best solution for the alkali powder is theoretical neutralization with acrylic acid, which is slightly alkaline, but if it is highly acidic, the strength of the gel will deteriorate.

In addition, due to the neutralization reaction between the main ingredient acrylic acid and the alkali in the auxiliary agent, the temperature rises by 5 to 8 degrees Celsius, resulting in a reaction delay due to the drop in water temperature during the cold season! It also has the advantage of preventing Note that there is a temperature rise of 35 to 40°C due to the heat of the polymerization reaction, and gelation occurs at 30°C.
It reaches that temperature in about 4 minutes in seconds.

Example 1) 8.75 parts of acrylic acid, 0.75 parts of ethylene glycol bisacrylamide, 0.75 parts of triethanolamine, and 3'9.75 parts of water were combined as main ingredients, and 2 parts of ammonium persulfate was added as an auxiliary agent. , 3.9 parts of caustic soda,
Mix 44.1 parts of water.

When 50 parts of main agent and 50 parts of auxiliary oil are mixed at 15°C, approximately 35%
It gels in seconds and becomes a transparent cassette-like solid with a chromaticity of 8 in a water quality test.

This gelled product is insoluble in water and can maintain sufficient strength and durability for use in water stop construction methods.

2 → 4 parts of acrylic acid, 0.75 part of ethylene name recall bisacrylamide, 0.1 part of ferrous sulfate, 45.15 parts of water
part is the main agent, 0.25 part of anthene persulfate, caustic soda,
The gelled product obtained by using 45 parts of IS and 2.3 parts of 4i of water as auxiliary agents has a red color, is translucent, and has excellent water resistance.

3) Acrylic acid IQ sound (base ingredients: 4.45 parts of hexacasinida, 0.75 parts of methyledibis acrylamide, 0.75 parts of triethanolamine, 34.05 parts of water, 1 part of anthene persulfate, 49 parts of water) The gelled product obtained by using ?W as an auxiliary agent has a chromaticity of 4 and is transparent.

By adjusting the amount of ammonium persulfate in this formulation, the following gelation time can be obtained.

Let the amount of ammonium persulfate be X parts.

X=L360 seconds at 3°G, 105 seconds at 5°C, 6 at 10°C
0 seconds at 15°C for 42 seconds, 20°C for 23 seconds, and 30°C for 17 seconds.

x=5, 7.5 seconds at O″G, 42 seconds at 5°C, 22 seconds at 15°C, 10 seconds at 20°C, 7 seconds at 25°C.

X=10, 40 seconds at 0°C, 23 seconds at 5°C, 1 at 10°G
5 seconds at 15°C, 12 seconds at 20°C, 7 seconds at 20°C.'' All of the gelled materials have strength and stability that can withstand use.

4) 8.75 parts of acrylic acid, 1.25 parts of methylenebisacrylamide, 25 parts of diethylaminoprobionitrile
parts, 39.75 parts of water as the main ingredient, 1.5 parts of anthene persulfate,
7.5 parts of Kasei Sokeda, 13 parts of calcium hydroxide, 2 parts of water
The gelled product obtained by using 8 parts as an auxiliary agent is a cloudy, strong solid and is water resistant.

Claims (1)

[Claims] A main ingredient consisting of N, N' ethylene diglycol thiacrylamide as a crosslinking agent and triethanolamine as an accelerator dissolved in an aqueous solution of acrylic acid, an oxidizing agent such as ammonium persulfate, and the amount of water necessary to almost neutralize the acrylic acid. A water stop method in which an aqueous auxiliary solution containing soda is created, and the auxiliary agent is mixed with main rain and injected at the construction site to form a water-insoluble sodium acrylate polymer in the soil.