JPS5920702B2 - Leak prevention agent - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a water leakage prevention agent that is used at the joints of pipe materials that mainly pass water such as industrial wastewater, sewerage systems, industrial water, and agricultural water.

As is well known, examples of pipe materials for the above purpose include Huyum pipes,
There are concrete pipes, etc., and pipes of appropriate length are successively joined to make a long pipe, and water is passed inside.

Therefore, there are many joints in the water passage, and there is a risk of water leakage if each joint is not reliably sealed.

Conventional water sealing methods for joints of pipe materials include filling the joint with asphalt, interposing a synthetic resin or synthetic rubber sheet or ring material in the joint, or tightening the outer circumferential surface with a band. , or by appropriately combining the above-mentioned means or filling the container with a chemical agent. However, none of these methods is perfect and has some drawbacks.

These deficiencies include the fact that the water sealing effect is not reliable, and after a long period of time, water leaks may occur due to ground movement or displacement, and the sealing work at joints is troublesome, so it takes a lot of time to seal many joints. These include the fact that it requires time and human resources, and that it cannot be provided at a low price. As a means to solve these drawbacks, as shown in Japanese Patent Application Laid-Open No. 49-125924, there is a spigot type joint in which a bell part at one end of a pipe material is fitted into a spigot part at the other end of another pipe material. This is a method in which a prepolymer or a mixture of the prepolymer and a filler, which has been reacted in advance with a NCO10H molar ratio of 1.0 to 2.0, is packed together with packing into the interior surrounded by the bell part and the spigot part.

According to this method, free N contained in the prepolymer
The CO group undergoes hydration polymerization, generates carbon dioxide gas, and the polymer expands and becomes elastic, filling the space between the bell section and the spigot section, enhancing the water sealing effect and preventing water leakage. .

However, even with this method, it is difficult to work because the prepolymer has a short curing time, and not only does it have poor adhesion to concrete, but the foam is not dense and is susceptible to change due to physical factors such as impact. Therefore, a sufficient water sealing effect cannot be expected, and furthermore, since the diameter of the bubbles existing inside becomes large, there is a risk that they will break and leak water over a long period of time.

The present inventors have completed the present invention as a result of research to eliminate the above-mentioned drawbacks. Mixing a hydraulic urethane prepolymer with a resin latex emulsion,
The present invention is characterized in that the mixture is filled into the joints of the pipe materials to form a foamed material.

When the urethane polymer having isocyanate groups and the resin latex emulsion are mixed, the resin component is dispersed inside the foam produced by the condensation reaction between the prepolymer and the water component contained in the resin latex emulsion. The resin component acts like an aggregate, providing sufficient elasticity.

Therefore, a sufficient water sealing effect can be achieved at the joints of the pipe materials. The isocyanates used in the present invention include tolylene diisocyanate and naphthalene diisocyanate.
・5. Diisocyanate, ethylene diisocyanate, trimethylene diisocyanate, tetramethylene ・
Diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, heptamethylene diisocyanate, phenylene diisocyanate,
It has two isocyanate groups, such as toluylene diisocyanate.

In addition, the polyols used in the present invention include diols such as ethylene glycol, polyethylene glycol, bisphenol dioxyethyl ether, bisphenol dioxypropyl ether, and neopentyl glycol, and these may be appropriately selected and combined. By doing so, a wide variety of reaction products with different properties can be obtained.

According to the present invention, the hydraulic urethane prepolymer is preferably a reaction product of an isocyanate and a polyol having an NCO/OH molar ratio in the range of 3.0 to 7.0. That is, if the ratio of NCO/0H is 3.0 or less, the content of NCO contained in the reaction product will be reduced,
The foaming ratio due to hydration reaction becomes smaller.

Therefore, the expansion rate caused by the hydration reaction becomes small, and the foam does not have sufficient elastic properties. On the other hand, if the NCO/OH ratio is 7.0 or more, the reaction product is of low molecular weight, ie, a bleed polymer with a low degree of condensation, and contains many free isocyanate groups.
Therefore, when foaming occurs due to the hydration reaction, the total volume of each bubble increases significantly, and the CO2 generated by the hydration reaction may not have the physical strength as a water leakage preventive agent.
cannot be trapped inside the mixture, and cannot be released to the outside to form a foamy substance.

As mentioned above, the molar ratio of NCO/OH is 3.0 to 7.
Hydraulic urethane prepolymer 1, which is a reaction product of polyol and isocyanate in the range of It is preferable to adjust and use it.

Any solvent may be used as long as it can dissolve the prepolymer, is volatile, and does not react with free isocyanate groups contained in the prepolymer, such as methyl ethyl ketone, Acetone, methyl isobutyl ketone, benzene, toluene, xylene, etc. can be used.

Examples of the resin latex emulsion to be mixed with the above-mentioned hydraulic urethane prepolymer include vinyl acetate emulsion, vinyl chloride emulsion, acrylic emulsion, epoxy emulsion, styrene-butadiene latex,
Among these resin latex emulsions, styrene-butadiene latex is particularly effective. can be used.

In addition, the content of the resin component in the resin latex emulsion is preferably 25 to 70% by weight; if it is less than 25% by weight, the effect of the resin component will not appear, and if it is more than 70% by weight, it will be disadvantageous in terms of stability and handling. become. Furthermore, although it is influenced by the mixing ratio of the urethane prepolymer and the resin latex emulsion, if the amount of the resin component is too large, the quality of the elastic foam produced will be adversely affected.

For example, it is preferable that the water component is 0.5 to 4 parts by weight per 1 part by weight of the urethane prepolymer, and the resin component is 0.1 to 2 parts by weight. The water component is 0.7 to 1.5 parts by weight, and the resin component is 0.7 to 1.5 parts by weight.
More preferable results can be obtained if the amount is 3 to 1.0 parts by weight. For example, if a resin latex emulsion containing 50% by weight of the resin component is used, it is suitable to mix about 0.25 to 3 parts by weight per 1 part by weight of the urethane polymer. When a hydraulic urethane prepolymer having free isocyanate groups is mixed with an aqueous resin dispersion solution, the free isocyanate groups contained in the urethane prepolymer undergo a condensation reaction with the water component of the resin latex emulsion, resulting in the production of CO2. When released, it becomes an elastic foam.

In this case, the resin component, which is the dispersoid of the resin latex emulsion, is mixed in a uniformly dispersed state inside the foam and functions as an aggregate, providing elasticity that does not occur in inorganic aggregates. In addition, it has extremely good adhesion to concrete and the like, and the resin component can suppress localized rapid foaming due to isocyanate groups, resulting in a dense foam with uniformly dispersed air bubbles. Furthermore, when the urethane prepolymer and the resin latex emulsion are mixed, the foam formation reaction is appropriately slow, so the curing of the foam is delayed, making it easier to handle when working at the joints of pipe materials, and improving work efficiency. can be increased.

Furthermore, the elastic foam according to the present invention has significantly higher adhesive strength and elasticity than foams made of a urethane prepolymer and water, or a urethane prepolymer, water, and an inorganic aggregate. Furthermore, if the foam does not contain a resin component, it will shrink, but by including an appropriate amount of resin component as in the present invention, it will not shrink even after a long period of time, and it will especially prevent water leakage from concrete pipe materials. It has remarkable effects as an inhibitor. Next, a method for connecting pipe materials using the water leakage preventive agent of the present invention will be described based on examples shown in the drawings.

The bell portion 3 at the other end of another tube 1'' is fitted into the spigot portion 2 at one end of the tube 1 to form an annular gap 4, and the outer opening portion of the gap 4 is made of synthetic rubber, synthetic resin, etc. The inner opening of the spacer 4 is sealed with a sealing member 7 provided with a plurality of small tubes 6 to tightly close the spacer 4. The small tube 61 is used for injecting the water leakage prevention agent, the small tube 62 at the top end is used for releasing internal air, and the other small tubes 6 are used for confirming injection.

It is preferable that each small tube 6 be made of transparent vinyl.
In addition, the small tube 61 is opened near the sealing material 7, and the small tube 62
is preferably opened near the ring material 5. on the other hand,
A solution tank 8 for a hydraulic urethane prepolymer, which is a reaction product of an isocyanate and a polyol and has a free isocyanate group at the terminal group, and a solution tank 9 for a resin latex emulsion are connected to supply pipes 10 and 11, respectively. Mixer 1
2, and the mixer 12 and the small tube 61 are connected by a connecting tube 13.

Then, from the solution tank 8, a solution of hydraulic urethane polymer in a desired amount is pumped to the mixer 12, and at the same time, from the solution tank 9, the resin latex emulsion solution is pumped to the mixer 12. Both solutions are mixed and injected into the spacer 4 from below through the connecting tube 13 and the small tube 61.

When the mixture is gradually injected into the space 4, it flows out from the confirmation small tube 6, so the small tubes 6 through which the mixture has flowed out are sequentially closed with stoppers (wires, bands, clips, etc.) to stop the mixture from flowing out.

When the mixture begins to flow out of the small tube 62, the mixer 12
From then on, the supply of the mixture to the space 4 is stopped and the X-curing is continued.

When the mixture in the spacer 4 becomes foamy due to curing, the sealing material 5 and each of the small tubes 6 are removed.

As a result, the spacing portion 4 is filled with elastic foam, and the joint portion between the two tubes 1 and 1' is tightly sealed. Note that the present invention is not limited to the pipe material having the above-mentioned spigot part and bell part, but can be applied to pipe materials having any other connection structure, and the pipe material is not limited to circular pipes, but also has rectangular cross sections, U-shaped pipes, etc.
It may have any shape, such as a letter shape, as long as it can tightly seal the joint.

Examples of the present invention are described below.

Example 1 A urethane prepolymer having a molecular weight of about 6,000 made by reacting tolylene diisocyanate and polyethylene glycol so that the NCO/OH molar ratio was 6.5 was diluted with methyl ethyl ketone and toluene to obtain a viscosity of 2,000 CP.
A solution (first solution) was prepared at S/20°C.

On the other hand, a styrene-butadiene latex solution (second liquid) having a resin component content of 60% by weight is prepared, and the first liquid and the second liquid are pumped by the means shown in FIGS. 1 and 2. The mixture was sent out using a mixer, mixed in an intermediate mixer, and filled into the joint of the Huum tube.

The mixing ratio of the first liquid and the second liquid is 1 part by weight of the first liquid to 1 part by weight, 2 parts by weight, and 4 parts by weight of the second liquid. Each test was conducted as a comparative example using water as the second liquid.

The test method is to fill the joint of the humid tube with the mixture and
After a minute had passed, water was passed through the inside of the humid pipe, and (1) water flow test was conducted, followed by a bending test of the internal joint while maintaining a water pressure of 1 kg/Crll. The results are as follows.

Example 2 A urethane prepolymer prepared by reacting trimethylene diisocyanate and bisphenol dioxyethyl ether such that the molar ratio of NCO/OH was 3.5 was diluted with methyl isobutyl ketone to obtain a viscosity of 1000 CPS/
A solution (first solution) was prepared at 20°C.

On the other hand, a styrene-ptadiene latex solution (second liquid) having a resin component content of 35% by weight was prepared, and the second liquid was 2 parts by weight per 1 part by weight of the first liquid, and the mixture was filled into the joint of the pipe material. .

The filling method and testing method were the same as in Example 1 above.

The test results were as follows: (1) Water pressure test showed no abnormalities up to 5 kg/CF7l, (4 bending tests showed no abnormalities at approximately 3 inclinations, and it was recognized that the product was sufficiently effective.

[Brief explanation of the drawing]

The drawings are schematic diagrams showing an embodiment of a method for sealing joints of pipe materials with the water leakage prevention agent of the present invention, and FIG. 1 is a longitudinal sectional front view, and FIG. 2 is a longitudinal sectional side view.

Claims (1)

[Scope of Claims] 1. A hydraulic urethane preform which is a reaction product of an isocyanate and a polyol with an NCO/OH molar ratio within the range of 3.0 to 7.0 and has a free isocyanate group at the terminal group. A water leak prevention agent comprising a polymer and a resin latex emulsion, wherein the hydraulic urethane prepolymer and the resin latex emulsion are used by mixing during work. 2 The hydraulic urethane prepolymer and the resin latex emulsion are mixed so that the resin content of the resin latex emulsion is 0.1 part by weight of the hydraulic urethane prepolymer.
The water leakage preventive agent according to claim 1, which is mixed in an amount of up to 2 parts by weight.