JPH0336865B2 - - Google Patents

Description

[Detailed description of the invention]

(a) Purpose of the invention "Field of industrial application" The present invention relates to a method for stopping water leakage from underground pipes, especially sewer pipes, and is widely used in the civil engineering and construction industry. . ``Prior Art'' Sewage pipes with a relatively small diameter buried underground are buried at a shallow depth and are easily damaged due to displacement of the ground and vibrations of vehicles running on the ground surface. Groundwater then flows in through these damaged areas, placing a burden on the terminal treatment plants and far exceeding their treatment capacity during rainfall. In some cases, sewage flows back into the ground, causing pollution such as groundwater contamination.
Such damage to sewage pipes is increasing with the spread of sewage systems, and is becoming a major social problem. This repair method is becoming established, and involves detecting the damaged area with a TV camera, placing a patch car inside the pipe, and filling the area with a chemical that turns into a gel after a certain period of time to close the damaged area. This is a method in which excess gel in the tube is removed using a water jet or the like. Water glass-based drugs are commonly used for this purpose, but the silicic acid gel produced tends to shrink and is slightly soluble in water, so it has the disadvantage that long-term effects cannot be expected. be. On the other hand, acrylamide-based materials have excellent durability, but are highly toxic, so much so that their use in chemical injection construction is prohibited under interim guidelines from the Ministry of Construction. Polyisocyanate-based chemicals are currently in use, but they use flammable organic solvents, so
There are disadvantages such as fire danger and groundwater contamination,
The toxicity of isocyanates to workers cannot be overlooked. Although drugs using magnesium acrylate are excellent in safety, they have the disadvantage that they cannot be cleaned with a water jet after injection because the gel they produce is cake-like and difficult to cut. Agents using polyethylene glycol methacrylate are also often used, but they tend to shrink after gelation and produce release water, resulting in insufficient performance. Slurry-based chemicals based on cement are also used, but because the solidified product is not flexible, they break due to the same reasons as sewage pipes, making it impossible to expect long-term effects. As mentioned above, many types of drugs have been devised, but at present none of them are satisfactory. ``Problem to be solved by the invention'' A chemical aqueous solution that gels after a predetermined time is injected from inside the damaged part of the sewage pipe, and after gelling, the excess gel is removed with a water jet to complete the repair. The properties required for a drug that can maintain its repair effect for many years are that it is inexpensive and has low toxicity, the gel has appropriate hardness and elasticity, it is easy to cut with water jets, and it is insoluble in water and easy to release. There is no generation of water, and there is no significant swelling due to water. Among the above-mentioned required performances, the present inventors did not generate release water, which is the main element of gel durability, and
In addition, we focused on the performance of no significant swelling due to water and good cutting properties, and conducted intensive studies to find a pharmaceutical composition that also satisfies various other properties. (b) Structure of the Invention ``Means for Solving the Problems'' The present inventors have discovered that a drug that satisfies the above-mentioned performance can be obtained by using a composition containing an acrylic acid salt and a polymerization catalyst such as polyethylene glycol diacrylate. They found that it can be obtained and completed the present invention. That is, in the present invention, a space in the pipe created by blocking the flow of liquid before and after the leakage point of the water leakage pipe is filled with a mixture of acrylate or methacrylate and polyethylene glycol diacrylate or polyethylene glycol dimethacrylate at a weight ratio of 8. /2～
A leaky pipe characterized in that an aqueous solution of the composition of 3/7 and a polymerization catalyst is sent and cured in the pipe interior space and the leakage location, and then the leakage location is repaired by removing the cured product in the pipe interior space. This relates to a repair method. (3) Polymerization catalyst ◎ (Meth)acrylate The (meth)acrylate used in the present invention refers to salts of acrylic acid or methacrylic acid with sodium, potassium, calcium, magnesium, zinc, aluminum, etc. Preferred for the present invention are sodium,
Magnesium and aluminum salts are preferred, and magnesium and sodium salts are more preferred. These (meth)acrylates are relatively inexpensive, water-soluble, and readily polymerize with redox catalysts to provide elastic gels. ◎ Polyethylene glycol di(meth)acrylate Polyethylene glycol di(meth)acrylate used in the present invention is obtained by esterifying polyethylene glycol and acrylic acid or methacrylic acid in the presence of an acid catalyst. For example, polyethylene glycol No. 400 (average molecular weight 380-420),
Examples include diesters from No. 600 (average molecular weight 570-630), and these acrylates may contain about 20 to 30% of mono(meth)acrylate by-produced in the above reaction. Note that water-soluble acrylates are preferred for the present invention. ◎ Polymerization Catalyst The polymerization catalyst used in the present invention preferably consists of a combination of an oxidizing agent and a reducing agent, and is preferably water-soluble. As the oxidizing agent, sodium, potassium, and ammonium persulfates are used. However, it is preferable to avoid ammonium persulfate since it generates ammonium when cement is used in the composition of the present invention. Reducing agents include amines such as diethanolamine, triethanolamine, hydrazine, hydroxylamine, dimethylaminopropionitrile, diethylaminoethanol, dimethylaminopropanol, piperazine, and morpholine, ferrous salts, sulfites, thiourea, and erythorbic acid. These include sodium, Rongarit, etc., and two or more types may be used in combination. Furthermore, when cement is used in combination, the use of these reducing agents can be omitted. The combination and amount of oxidizing agent and reducing agent are as follows:
Since it affects the gelation time and physical properties of the gel, it should be selected depending on the working conditions and other factors. ◎ Compounding ratio In the composition of the present invention, the combined ratio of (meth)acrylate and di(meth)acrylate is important because it greatly influences the physical properties of the gel. According to the research of the present inventors, the weight ratio of (meth)acrylate to di(meth)acrylate is 8:2-3:7, preferably 7:3-4:6. If the weight ratio is outside this range, the strength of the gel will decrease and there is a risk that water will separate. The composition of the present invention is used as an aqueous solution or dispersion, and the concentration of the (meth)acrylic acid compound in this case is preferably 5-30%, more preferably 7-20%. If the concentration is 30% or more, a hard gel can be obtained, but this is not economical, and since the reaction generates a large amount of heat, the water stoppage may be incomplete due to shrinkage due to cooling, which is undesirable. If the concentration is less than 5%, a weak gel can be obtained. However, this is still not desirable. The composition of the present invention can also be used in combination with cement, and when used in combination with cement, the amount of cement in 1L of chemical solution is
Preferably 600g or less, more preferably 400g
It is as follows. If the weight exceeds 600 g, the gel obtained will be too hard and have poor elasticity. The combination and amount of redox catalysts used will affect the gelation time of the composition, so many conditions such as concentration and composition of the composition, pumping distance, piping dimensions, temperature, and ease of penetration of the composition will affect the gelation time of the composition. It is necessary to consider and choose. In normal construction, 10 seconds-3
A gelation time of about a minute is sufficient, so
Set it so that it looks like this. In construction, a common method is to pump solutions containing an oxidizing agent and a reducing agent separately, and then merge them just before the sewage pipe breaks. (meta)
The acrylate and di(meth)acrylate may be present separately in the oxidizing agent or reducing agent solution, or in a mixed state in either the oxidizing agent or reducing agent solution. When using cement, (meta)
It is undesirable for either acrylate, di(meth)acrylate, or oxidizing agent to coexist with cement. ◎ Construction method: A TV camera is towed inside the sewer pipe to detect the damaged area from the CRT image, a rubber gas car is installed to sandwich the area, and air is sent into the gas car to inflate it and the sewer pipe is closed. Cut off. The composition of the present invention is fed into the blocked sewer pipe using a pump or a head, and injected into the damaged area. The liquid is fed for a predetermined period of time, or when it becomes impossible to inject due to the onset of gelation, the liquid feeding is stopped, and after at least the gelation time of the composition has elapsed, the air is removed from the packer, the packer is deflated, and the puller is attached to the traction wire. Twist it and pull it out. At this time, most of the gel protruding into the sewer pipe is cut off. Afterwards, the inside of the pipe is further cleaned with a high-pressure water stream to complete the work. If necessary, the quality of the repair will be confirmed by a pressure test. Incidentally, cases of liquid delivery of the composition are listed as follows. The drug herein refers to a mixture of (meth)acrylate and polyethylene glycol di(meth)acrylate. A mixture of chemicals, oxidizers, and reducing agents A mixture of chemicals, oxidizers, cement, and, if necessary, a reducing agent A mixture of chemicals and oxidizers and a mixture of chemicals and reducing agents are pumped separately to make a packer. A mixed solution of chemicals and oxidizing agents, and a cement slurry containing a reducing agent if necessary, are pumped separately and mixed inside the tank.An oxidizing agent or a chemical containing a reducing agent, and an aqueous solution of a reducing agent or oxidizing agent. A (meth)acrylate solution containing an oxidizing agent or reducing agent and a polyethylene glycol di(meth)acrylate solution containing a reducing agent or an oxidizing agent are pumped separately and mixed in the packer. When the composition of the present invention is injected into a leaking part of a damaged sewer pipe or a partition wall installed to block water and gelled, there is no generation of separation water and no water-swelling properties. , is inexpensive, has low toxicity, has appropriate hardness and elasticity, and has excellent cutability with a water jet, so gel that protrudes from the leak can be easily cleaned with a water jet, and the gel that forms at the leak can be cleaned. It is highly flexible and does not shrink or swell significantly in water, so it has an excellent ability to effectively close leakage gaps for many years. "Examples and Comparative Examples" Example 1 Solution A containing 96 g of magnesium acrylate and 12 g of sodium persulfate in 500 ml, and 64 g of diacrylate of polyethylene glycol No. 400 in 500 ml.
A composition consisting of two liquids, liquid B containing 3 g of sodium erythorbate, was prepared and mixed at 24°C, which gelled in 58 seconds to obtain an elastic translucent gel. This gel did not release any water. Further, this gel was immersed in water at room temperature for 7 days, but no swelling was observed. Thickness after 30 minutes of gelation
When I stretched a 0.2 mm nylon thread tightly with both hands and pressed it against the gel, it was easily cut. The composition of this composition is magnesium acrylate: polyethylene glycol diacrylate = 6:4 (weight ratio), and the total concentration of both is 15% by weight. Comparative Example 1 A composition consisting of two solutions, solution A containing 80 g of magnesium acrylate and 12 g of sodium persulfate in 500 ml, and solution B containing 80 g of magnesium acrylate and 3 g of sodium erythorbate in 500 ml, was
When mixed at ℃, gelatinized in 7 seconds to obtain bait-like gel. Although this gel contracted and produced a large amount of water, it did not swell when immersed in water. Also,
Similar to Example 1, cutting with a nylon thread was attempted, but it was only deformed and could not be cut. Note that the concentration of magnesium acrylate in this composition is 15% by weight. Example 2-14, Comparative Example 2 Various compositions were prepared by changing the type and amount of acrylate and the type and amount of polyethylene glycol di(meth)acrylate in Example 1, and the release of the gel obtained thereby The swelling properties by immersion in sewage and water, and the cuttability by nylon thread were as shown in Table 1. In addition, in the table, salt means (meth)acrylate, diester means polyethylene glycol di(meth)acrylate, and the type of raw material polyethylene glycol and (meth)acrylic acid are shown. .

【table】

[Table] Example 15 96g of magnesium acrylate, 64g of polyethylene glycol No. 400 diacrylate in 500ml,
A composition consisting of two liquids, liquid A containing 12 g of sodium persulfate and liquid B containing 250 g of blast furnace colloid cement in 500 ml, was prepared and mixed at 24°C.
It gelated in seconds to obtain an elastic gel. This gel did not produce any release water and did not swell after being soaked in water for 7 days. Moreover, the cuttability with the nylon thread was also good. By immersion in water, the gel gradually became hard, but did not lose its elasticity and there was almost no change in volume. Examples 16-18 In Example 15, various compositions were prepared by changing the cement and its amount, and the properties of the resulting gels were measured. Table 2 shows the results.

[Table] Construction Example 1 A sewage pipe made of hard vinyl chloride with an inner diameter of 30 cm was inspected with a television camera, and it was found that water was leaking at the pipe connection. Narrow down the position, install a packer, blow air to inflate the packer, and shut off the pipe. A having the same composition as in Example 1,
Mixed solution B was pumped at the same speed, mixed in a sealed tank, and injected into the outside of the pipe and into the ground through the leaking part of the sewer pipe. A, B
When I sent about 25 grams of each of the mixed solutions, gelation started and I was no longer able to send the solution. After about 5 minutes, the air in the police car was let out and the car was pulled out using wires. At this time, most of the gel protruding inside the tube was cut away. When the gel was subsequently sprayed with high-pressure water, the gel was successfully cleaned. The next day, an inspection using a television camera confirmed that the water leak had completely stopped. (c) Effect The composition of the present invention can be used for underground pipes,
In particular, it is excellent in preventing water leakage from sewage pipes very easily and effectively, and can prevent an increase in the amount of water treated at sewage treatment plants due to water leakage and the occurrence of pollution due to water leakage. This is beneficial, and the effects of the repair method of the present invention are immeasurable.

Claims (1)

[Claims] 1. In the space inside the pipe created by blocking the flow of liquid before and after the leakage point of the water leakage pipe, apply a mixture of acrylate or methacrylate and polyethylene glycol diacrylate or polyethylene glycol dimethacrylate at a weight ratio of 8/2 to 3. A water leakage pipe characterized in that the aqueous solution of the composition of /7 and a polymerization catalyst is sent and cured in the pipe interior space and the water leakage location, and then the water leakage location is repaired by removing the cured product in the pipe interior space. Repair method.