JPH0725964A - Two pack type foamable polyurethane foam composition - Google Patents

Abstract

PURPOSE:To provide a two pack type foamable polyurethane foam composition for improving base rocks, purposing to reinforce weak grounds or prevent the subsidence of the grounds by injecting the polyurethane foam composition into the weak grounds having many spaces or into spaces generated on the back surfaces of underground structures and filling the spaces in a short time. CONSTITUTION:A two pack type foamable polyurethane foam composition comprises a liquid A comprising 0.05-35wt.% of a liquid rubber, a polyol liquid containing a primary polyol having two or more hydroxyl groups as a main component, a catalyst, a foaming agent, and a foam stabilizer, and a liquid B containing a polyisocyanate having an NCO content of 20-40wt.%. Or, a two pack type foaming polyurethane foam composition comprises a liquid A comprising a polyol containing a primary polyol having two or more hydroxyl groups as a main component, a catalyst, a foaming agent and a foam stabilizer, and a liquid B containing a polyisocyanate containing 0.05-35wt.% of a liquid rubber prepolymer prepolymerized with NCO groups.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is to reinforce a ground by injecting it into a void formed on the back surface of an underground structure such as a soft ground having many voids or a tunnel, and filling the void in a short time, or The present invention relates to a two-component foamed polyurethane foam composition for rock improvement, which is intended to prevent problems such as tunnel construction by preventing ground subsidence, and relates to a method for producing a foamed polyurethane foam using the same.

[0002]

2. Description of the Related Art Conventionally, as a method of filling soft ground with many voids or a method of filling voids between underground structures such as tunnels and the ground, cement construction method for injecting cement or injection of polyurethane chemical liquid There are known methods such as the urethane method, but each of them has advantages and disadvantages,
The performance that the user was not sufficiently satisfied with was not obtained (Japanese Patent Publication No. 56-150298, Japanese Patent Publication No. 60-59947, Grout Handbook p253 to 257 S42.3 Lattice).

That is, the cement construction method has problems that the material itself is inexpensive, but that the construction is troublesome and that it takes a long time to cure.

On the other hand, the urethane construction method is easy to construct and completes hardening within one hour, so the construction progresses quickly and is an important construction method for tunnel construction. It is extremely expensive as compared with cement itself, so when the purpose is to fill the voids, increase the expansion ratio as much as possible to reduce the amount of polyurethane chemical liquid actually used per 1 m ^{3 of} voids. There were issues such as the necessity.

At present, the polyurethane chemical liquid marketed for rock bed modification has a foaming ratio adjusted to 10 to 15 times by using water as a foaming agent.

It is said that the high expansion ratio polyurethane chemical liquid marketed for filling voids has an expansion ratio of 20 to 30 times, but the final expansion ratio reaches 30 times due to shrinkage after curing and other reasons. The current situation is not.

However, when the purpose is mainly to fill voids, it is not possible to compete with cement in terms of cost unless the expansion ratio is increased as much as possible and the amount of the polyurethane chemical liquid used per 1 m ^{3 of} voids is reduced. The current situation.

[0008] Generally, in a cold cure method in which a material such as a polyurethane chemical liquid for rock solidification is foamed and cured at room temperature, water is used as a foaming agent, but the reaction conditions are unstable and the polyurethane foam becomes brittle. There is a problem that the degree of chemical conversion becomes large and a high expansion ratio cannot be obtained.

Further, in the cold cure method, the expansion ratio of polyurethane foam is limited to about 30 times, and if the expansion ratio is higher than that, the foam will be broken during the expansion or shrinkage with time occurs after curing, After several days, there was a problem that the volume tended to be about 1/2 of the volume immediately after curing.

When a polyurethane chemical liquid is injected for the purpose of filling voids in the ground, no matter how large the foaming ratio thereof is, if a slight shrinkage occurs with the passage of time after the injection, a new void will be created, and Since it causes fluctuation, the polyurethane foam foamed with the urethane chemical liquid used for this purpose cannot allow a slight shrinkage.

Generally, cement-bentonite grout or the like is often injected for backfilling between the ground and the segment such as a long tunnel.

[0012] However, it takes about 3 to 12 hours for the cement-bentonite grout to harden, and the cement-bentonite grout injected hardens because the voids are often continuous in a long tunnel or the like. However, there was a problem that it was difficult to achieve the desired backfill injection.

Therefore, in part, a polyurethane chemical liquid system,
1 to 5 using cement-based or water-glass-based injection materials
The cement-bentonite grout is injected after grouting about m to make partitions and eliminating continuous voids.

Thus, a grout like a partitioning material that eliminates continuous voids is called a stopper grout, and a polyurethane chemical liquid injection material has a certain degree of viscosity and is quick-hardening, so it is unnecessary. It is preferable as a stopper grout because it does not flow out, it largely foams at the injected portion and surely fills the continuous voids.

However, the conventional polyurethane chemical liquid type injection material has a small amount of foaming, which results in high material cost, shrinks in a few days, and even if cement-bentonite grout injection work is performed, There is a problem that a gap is generated, which makes it difficult to obtain the effect as a stopper grout.

Further, the cement-based injecting material has a problem that it has a good fluidity and a large outflow, and it is difficult to obtain an effect as a stopper grout particularly in a large void of 30 cm or more.

Further, the water-glass type injection material is not durable and, like the cement-type injection material, has a problem that it is difficult to obtain the effect as a stopper grout in a large void of 30 cm or more.

The present inventor has conducted various studies to solve the above-mentioned problems of the prior art, and as a result, if a specific composition is used,
The present invention has been completed based on the finding that it is possible to provide a foamed polyurethane foam in which the volume of the foamed molded product hardly shrinks with time.

[0019]

That is, according to the present invention, a polyol liquid containing 0.05 to 35% by weight of a liquid rubber and having a primary polyol having two or more hydroxyl groups as a main component, a catalyst, a foaming agent, and Liquid A containing a foam stabilizer and NCO content of 20
A two-component polyurethane foam composition comprising a liquid B containing 40 to 40% by weight of polyisocyanate, the polyol liquid containing a primary polyol having two or more hydroxyl groups as a main component, A liquid A containing a catalyst, a foaming agent, and a foam stabilizer, and a liquid B containing polyisocyanate as a main component containing 0.05 to 35% by weight of a liquid rubber prepolymer prepolymerized with NCO. Which is a two-component polyurethane foam composition
Furthermore, a liquid A containing a primary polyol having two or more hydroxyl groups as a main component, a foaming agent, a catalyst, and a foam stabilizer, and a liquid B containing a polyisocyanate. A method for producing a foamed polyurethane foam, which comprises reacting in the presence of liquid rubber.

The present invention will be described in detail below.

In the present invention, the liquid A and the liquid B react to produce a foamed polyurethane foam.

The liquid A is a polyol liquid containing a primary polyol having two or more hydroxyl groups as a main component, a catalyst,
It comprises a foaming agent and a foam stabilizer.

The polyol solution according to the present invention has 2 hydroxyl groups.
The main component is a primary polyol having at least one, and the chain is extended by a polyol generally used for polyurethane foam production, that is, ethylene oxide or propylene oxide, and OH groups are attached to both terminals. Further, it is possible to use a polyoxyalkylene polyol having an average molecular weight of 100 to 8,000, ethylene glycol, propylene glycol, triethylene glycol,
It is preferable to use glycerin, a castor oil-modified polyol having OH groups at both ends of castor oil, and a bifunctional or higher functional polyol having a molecular weight of 100 to 8,000 obtained by modifying triethanolamine or the like with propylene oxide or the like.

The catalyst according to the present invention generally includes organic aliphatic amines such as triethylenediamine and dimethylethanolamine, and can be used in combination with a metal catalyst such as dibutyltin dilaurate and stannous chloride. . The amount of the catalyst used is determined according to the required curing time or the temperature at the time of use, and is not particularly limited, but it is 2 per 100 parts by weight of the polyol.
-4 parts by weight is common.

The foaming agent according to the present invention is not particularly limited, but it is preferable to use water from the viewpoint of use in a tunnel. The amount of foaming agent used is usually
If the expansion ratio is about 10 times, it is 0.5 to 2 parts by weight with respect to 100 parts by weight of the polyol, but in order to make the expansion ratio 30 times or more, it is preferably 5 to 6 parts by weight.

The foam stabilizer according to the present invention is used from the viewpoint of obtaining a more dense polyurethane foam, and is not particularly limited, but a silicone-based foam stabilizer can be used. The amount of the foam stabilizer used is 1 to 3 parts by weight based on 100 parts by weight of the polyol.

The solution B contains an isocyanate.

As the isocyanate liquid of the liquid B according to the present invention, polyisocyanates generally used for producing polyurethane foam can be used.
It is possible to use tolylene diisocyanate (TDI), crude TDI, 4, '4-diphenylmethane diisocyanate (MDI), crude MDI, etc., but among these, industrial crude MDI having an isocyanate group content of 30 to 31.5%. Is preferably used.
When adding liquid rubber to liquid B, add liquid rubber
It is preferable to use the NCO prepolymer as a mixture in the liquid B.

The liquid rubber used in the present invention has a molecular weight of 500 to 5,000 having a hydroxyl group or a carboxyl group at the molecular end.
The liquid rubber, and it is more preferable to use polybutadiene rubber or polychloroprene rubber.

In the present invention, liquid rubber is mixed with liquid A,
Alternatively, it is used as a mixture in solution B.

When the liquid rubber is used by mixing with the liquid A, the content of the liquid rubber in the liquid A is preferably 0.05 to 35% by weight, more preferably 0.1 to 10% by weight, based on 100 parts by weight of the polyol. preferable. If it is less than 0.05% by weight, the amount of shrinkage will be large, and if it exceeds 35% by weight, the expansion ratio will be small, and
The viscosity of the liquid A increases, and the injection property into the rock tends to be poor.

When the liquid rubber is used without being added to the liquid A, a liquid rubber prepolymer prepared by mixing the liquid rubber and the isocyanate is used as the liquid B. In particular, obtained from the reaction of liquid rubber with 4'4'-diphenylmethane diisocyanate, for example with an NCO concentration of 1
It is preferred to use ~ 10 wt% liquid rubber prepolymer.

When the liquid rubber is mixed and used in the liquid B, the content of the liquid rubber prepolymer in the liquid B is 0.2 to 3
5% by weight is preferable, and 0.5 to 10% by weight is more preferable. When the content of the liquid rubber prepolymer is less than 0.2% by weight, the amount of shrinkage of the urethane foam increases, and when it exceeds 35% by weight, the viscosity of the solution B increases and the injection property into rock tends to be poor.

Next, a method for mixing the two-pack type polyurethane foam composition of the present invention will be described.

First, the liquid A and the liquid B are separately fed by separate pumps, mixed immediately before injection, and used as stopper grouts for backfilling voids such as tunnels.

The mixing method is not particularly limited as long as the liquid A and the liquid B can be sufficiently mixed, and a method such as a shot mixer capable of mixing the two liquids in the flow path is preferable. If the mixing is insufficient, the reaction between the liquid A and the liquid B will be partial, and sufficient foaming may not be performed.

Next, a method of applying the two-component polyurethane foam composition of the present invention as a stopper grout will be described.

Boring and injecting is performed for each support work of about 1 m in the traveling direction of the tunnel. In addition, boring is performed at 50 cm intervals along the inner circumference of the tunnel.

For the injection into the void, a hollow lock bolt having an injection hole at the tip of 1 to 5 m is passed through for pressure injection.

The injection amount of the two-pack type polyurethane foam composition of the present invention is controlled by taking into consideration the filling condition by increasing the injection pressure. Usually, it is necessary to prepare a two-pack type polyurethane foam composition having an expected void volume of about 1.5 to 2 times.

Since the injection pressure is intended to fill only the voids, it is necessary to control it as low as possible, and usually the pressure is 1 to 15 kg / cm ² or less.

As the injection pump, it is preferable to use an air-driven or electric gear pump because the pressure that can sufficiently correspond to the injection pressure is obtained.

Liquid A and liquid B are separately fed under pressure, mixed and mixed immediately before injection in a tunnel or the like, and continuously mixed and injected by a shot mixer or the like.

The curing and foaming time varies depending on the situation, but is preferably about 1 minute for the purpose of gap filling.

[0045]

The present invention will be further described below based on examples.

Example 1 70 parts by weight of polyol A, 20 parts by weight of polyol B, 10 parts by weight of polyol C, 2 parts by weight of catalyst a, 1 part by weight of catalyst b, 6 parts by weight of water, and 1 part by weight of a foam stabilizer were added to Table 1. As shown, liquid rubber was added to prepare liquid A. Equivalent amounts of this liquid A and liquid B made of polyisocyanate were mixed and reacted. Table 1 shows the compounding amount of the added liquid rubber, the expansion ratio of the composition, and the shrinkage ratio of the foamed molded product. In addition,
The shrinkage rate was measured as the volumetric shrinkage rate of a cylindrical foam-molded article produced in a 2,000 cc beaker after 25 days at 25 ° C.

<Materials used> Polyol A: polypropylene glycol, average molecular weight
700 Polyol B: Polypropylene glycol, average molecular weight
2,000 Polyol C: Ethylene glycol manufactured by Mitsui Toatsu Co., Ltd. Catalyst a: Triethylenediamine manufactured by Mitsui Toatsu Co., Ltd. Catalyst b: Dibutyltin dilaurate foam stabilizer, manufactured by Nitto Kasei Co., Ltd .: Product name “L-3601” manufactured by Nitto Unicar Liquid rubber α : Polybutadiene manufactured by Idemitsu Chemical Co., Ltd., product name "P
oly bd R-45HT ”Liquid rubber β: Chloroprene manufactured by Denki Kagaku Kogyo Co., Ltd., product name“ LCR-FH050 ”Isocyanate: Mitsui Toatsu Co. product name“ MDI-CR200 ”, NCO
Content 31-34% by weight

[0048]

[Table 1]

Example 2 70 parts by weight of polyol A, 20 parts by weight of polyol B, 10 parts by weight of polyol C, 2 parts by weight of catalyst a, 1 part by weight of catalyst b, 6 parts by weight of water, and 1 part by weight of a foam stabilizer were mixed to prepare a liquid A. . B
As the liquid, with respect to 100 parts by weight of polyisocyanate,
Using a mixture of liquid rubber γ as shown in Table 2, A
The same procedure as in Example 1 was carried out except that the same amount as the liquid was blended.
The results are also shown in Table 2.

<Materials to be used> Liquid rubber γ: trade name “Poly bd MC-50” manufactured by Idemitsu Kabushiki Kaisha, a liquid rubber prepolymer obtained by the reaction of liquid rubber α and isocyanate, diluted with dioctyl phthalate.

[0051]

[Table 2]

Example 3 After drilling in the circumferential direction of the headrace tunnel of an electric power plant of Denki Kagaku Kogyo Co., Ltd., which was excavated by the blasting method 30 years ago, the condition of the tunnel and the ground was observed with a fiberscope. . As a result, there was a gap of 10 to 40 cm between the concrete and the ground, especially in the sky field. Also,
Many foreign substances were confirmed in the falling objects and supporting materials on the ground.
Two rows were injected into the tunnel cross-section at intervals of 1 m to form a stopper grout zone. The injection hole was bored every 50 cm. 70 parts by weight of polyol A, 20 parts by weight of polyol B,
Liquid A was prepared by mixing 10 parts by weight of polyol C, 2 parts by weight of catalyst a, 1 part by weight of catalyst b, 6 parts by weight of water, and 1 part by weight of foam stabilizer. Further, liquid rubber γ is replaced with isocyanate and liquid rubber γ.
5 parts by weight for 100 parts by weight in total of B
The solution was mixed with the solution A in the same amount. The expected void volume of the tunnel
30 cm, using a two-component pump consisting of an air pump and a gear pump, one place has the same amount as the expected void volume, and one place has 1.
Five volumes were injected and one site was doubled. In the calculation, the injection zone was set at 2 m in the lateral direction.

As a result, the same amount as the expected void amount and 1.5 times the total amount were injected, but the double amount was not injected,
When the amount was 1.8 times, the pressure became 15 kg / cm ² or more and injection could not be performed. The injection status was confirmed by boring every 50 cm in the tunnel. As a result of checking the injection status, the same amount as the expected void volume,
Both the 1.5-fold injection and the 2-fold injection were sufficiently injected, the adhesion to the ground was sufficient, and there was no gap. In the double injection, polyurethane foam was confirmed up to 2.5 m depending on the injection site at the bottom of the tunnel, and up to 1.5 m in the sky. Also, in the case of injection of 1.5 times the amount, it was confirmed that the height was 2 m at the bottom and 1 m at the sky. Furthermore, with the same amount of injection, up to 1.5 m was confirmed in the lower part and up to 1 m in the sky.

Cement-bentonite grout was then injected. All cement in the stopper grout
Bentonite grout remained and did not flow out other than that, and the backfilling injection into the tunnel could be performed reliably. Also, the backfilled tunnel has no water leakage and its durability is improved.

Example 4 The same procedure as in Example 3 was carried out, except that the back-filling injection with cement-bentonite grout was carried out without injecting the two-pack type polyurethane foam composition of the present invention.

As a result, there was not enough concrete at the top of this tunnel, the voids were continuous, and the length was 6 km.
Therefore, even if cement-bentonite grout was injected, it flowed along the slope of the tunnel, the filling could not be completed forever, and it could not be integrated with the ground.

Example 5 A cement-water glass type injection material having a gel time of 30 seconds was used as a stopper grout, and back-filling injection with cement-bentonite grout was carried out in the same manner as in Example 3.

According to the results of the boring, even if the injection amount was twice the expected amount of the void, it was not possible to completely fill the void in the heavenly field, so that the cement-bentonite grout flowed out over a wide area, and the heavenly part was sufficiently filled. It could not be filled. Also, using a cement-based injecting material consisting of quick-setting cement, as well as cement-water glass-based injecting material,
It could not be filled sufficiently.

[0059]

EFFECT OF THE INVENTION By using the urethane foam composition of the present invention, a non-shrinkable foamed molded product can be obtained with a high expansion ratio of about 40 times, and not only small voids but also large voids of 1 m or more depending on the location. Can be filled completely, and in a short time. Further, the urethane foam composition of the present invention is effective as a stopper grout because voids do not re-occur even after a long time has passed after being injected into the voids of the ground. Further, since there is no shrinkage after curing and the strength is strong, there is an effect that it can be injected alone for ground improvement and reinforcement. Further, since it does not cause the fluctuation of the ground and has a high expansion ratio, it has an effect that it can be cost-effective even when compared with cement or other inexpensive inorganic injection materials.

Continuation of the front page (51) Int.Cl. ⁶ Identification number Reference number in the agency FI Technical display location C08G 101: 00) C08L 75:04 C09K 103: 00 (72) Inventor Kenkichi Hirano Omi Aomi, Aomi Town, Nishikubiki-gun, Niigata Prefecture 2209 Denki Kagaku Kogyo Co., Ltd., Aomi Plant (72) Inventor Isamu Terashima Omi, Aomi-cho, Nishikubiki-gun, Niigata 2209 Denki Kagaku Kogyo Co., Ltd., Aomi Plant (72) Inventor Takashi Mobe, Aomi-cho, Nishikubiki-gun, Niigata Aomi 2209 Address Denki Kagaku Kogyo Co., Ltd. Aomi Factory

Claims (3)

[Claims] 1. A liquid containing 0.05 to 35% by weight of liquid rubber and containing a primary polyol having two or more hydroxyl groups as a main component, a catalyst, a foaming agent, and a foam stabilizer. And a liquid B containing a polyisocyanate having an NCO content of 20 to 40% by weight. 2. A liquid containing a polyol liquid containing a primary polyol having two or more hydroxyl groups as a main component, a catalyst, a foaming agent, and a foam stabilizer, and a liquid rubber prepolymer prepolymerized with NCO. A two-part type polyurethane foam composition comprising a liquid B containing a polyisocyanate as a main component and containing 0.05 to 35% by weight of a polymer. 3. A liquid containing a polyol liquid containing a primary polyol having two or more hydroxyl groups as a main component, a foaming agent, a catalyst and a foam stabilizer, and a B liquid containing a polyisocyanate. A method for producing a foamed polyurethane foam, which comprises reacting with and in the presence of liquid rubber.