JP3226126B2 - Two-part foamed polyurethane foam composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a method for strengthening a ground by injecting it into a soft ground having many gaps or a gap formed on the back of an underground structure such as a tunnel and filling the gap in a short time. The present invention relates to a two-pack type foamed polyurethane foam composition for bedrock reform, which aims to prevent problems such as tunnel construction by preventing land subsidence, and to a method for producing a foamed polyurethane foam using the composition.

[0002]

2. Description of the Related Art Conventionally, as a method of filling soft ground with many voids, a method of filling a gap between an underground structure such as a tunnel and the ground, a cement method of injecting cement, or a polyurethane chemical solution. There are known urethane construction methods, but each has its advantages and disadvantages,
No satisfactory performance was obtained for the user (Japanese Patent Publication No. 56-150298, Japanese Patent Publication No. 60-59947, Grout Handbook p253-257, published by S42.3 Lattice).

[0003] In other words, the cement method has problems that the material itself is inexpensive, but the work is troublesome, and it takes a long time to harden.

[0004] On the other hand, the urethane method is simple in construction, and hardening is completed within one hour, so that the progress of construction is fast and is an important method for tunnel construction. it itself is very expensive compared to the cement, therefore, in case it is intended to fill voids, to increase the possible expansion ratio, reduces the polyurethane chemical quantity which is actually used per gap 1 m ³ There were issues such as necessity.

[0005] Currently, polyurethane chemicals on the market for bedrock reforming are adjusted to have a foaming ratio of 10 to 15 times by using water as a foaming agent.

[0006] The foaming ratio of a polyurethane solution with a high foaming ratio, which is marketed for filling voids, is said to be 20 to 30 times, but the final foaming ratio reaches 30 times due to shrinkage after curing and the like. It is not at present.

However, if the purpose is mainly to fill the voids, it is impossible to compete with cement in terms of cost unless the foaming ratio is increased as much as possible and the amount of the polyurethane chemical used per 1 m ^{3 of} the voids is reduced. It is the current situation.

[0008] In general, in the cold cure method of foaming and hardening a material such as a polyurethane chemical for rock consolidation at room temperature, water is used as a blowing agent, but the reaction conditions are unstable and the polyurethane foam is brittle. However, there is a problem that the degree of conversion becomes large and a high expansion ratio cannot be obtained.

Further, in the cold curing method, the expansion ratio of polyurethane foam is limited to about 30 times. If the expansion ratio is higher than that, the foam may break during the foaming or may shrink with time after curing. Several days later, there were problems such as a tendency to become about に な る of the volume immediately after curing.

[0010] In addition, when a polyurethane chemical is injected for the purpose of filling voids in the ground, no matter how large the expansion ratio is, even if it shrinks a little over time after the injection, new voids are generated, Due to fluctuations, the foamed polyurethane foam applied with the urethane chemical used for this purpose was not allowed to slightly shrink.

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

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

[0013] For this reason, partially, a polyurethane chemical solution system,
1-5 by using cement or water glass type injection material
Grout is performed by grouting about m to eliminate continuous voids and then cement-bentonite grout is injected.

As described above, the grout which acts as a partitioning material and eliminates continuous voids is called a stopper grout. The polyurethane chemical-based grouting material has a certain degree of viscosity and is quick-curing. It is preferable as a stopper grout because it does not flow out, foams largely at the injected portion, and reliably fills continuous voids.

However, the conventional polyurethane chemical-based injection material has a low foaming amount, which increases the material cost, and shrinks in a few days. There has been a problem that a gap is generated, which makes it difficult to obtain the effect as a stopper grout.

[0016] In addition, the cement-based injection material has a problem that the flowability is good and the outflow is large, and the effect as a stopper grout is hard to be obtained particularly in a large gap of 30 cm or more.

Furthermore, the water-glass-based injection material has a problem in that it has no durability and, like the cement-based injection material, it is difficult to obtain an effect as a stopper grout in a large gap 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, using a specific composition,
The inventors have found that it is possible to provide a foamed polyurethane foam in which the volume of the foamed molded product hardly shrinks over time, and have completed the present invention.

[0019]

That is, the present invention relates to a polyol solution containing 0.05 to 35% by weight of a liquid rubber and containing a primary polyol having two or more hydroxyl groups as a main component, a catalyst, a blowing agent, and and a liquid comprising a foam stabilizer, 2, characterized in that it consists of liquid B comprising a polyisocyanate
A liquid foamed polyurethane foam composition, comprising a polyol solution containing a primary polyol having two or more hydroxyl groups as a main component, a solution containing a catalyst, a foaming agent, and a foam stabilizer, and a prepolymer comprising NCO. Liquid rubber prepolymer
A two-component foamed polyurethane foam composition comprising a liquid B containing a polyisocyanate as a main component containing 0.05 to 35% by weight, further comprising a primary polyol having two or more hydroxyl groups as a main component. A liquid comprising a polyol liquid, a foaming agent, a catalyst, and a foam stabilizer, and
A method for producing a foamed polyurethane foam, comprising reacting a liquid B containing a polyisocyanate in the presence of a liquid rubber.

Hereinafter, the present invention will be described in detail.

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

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

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

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

The foaming agent according to the present invention is not particularly limited, but water is preferably used from the viewpoint of use in a tunnel. The amount of foaming agent used is usually
If the expansion ratio is about 10 times, the amount is 0.5 to 2 parts by weight with respect to 100 parts by weight of the polyol. However, in order to increase the expansion ratio to 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 denser 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.

Liquid B contains isocyanate.

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

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

In the present invention, the liquid rubber is mixed with the liquid A,
Alternatively, it is used by mixing in the 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 increases, and if it exceeds 35% by weight, the expansion ratio decreases, and
The viscosity of the liquid A tends to increase, and the injection property into the rock tends to be poor.

When the liquid rubber is used without being added to the liquid A, the liquid rubber prepolymer prepared by mixing the liquid rubber and the isocyanate is used as the liquid B. In particular, the NCO concentration obtained from the reaction of liquid rubber with 4'4'-diphenylmethane diisocyanate, for example, when the NCO concentration is 1
It is preferred to use 1010% by weight liquid rubber prepolymer.

When the liquid rubber is mixed with the liquid B and used, the content of the liquid rubber prepolymer in the liquid B is 0.2 to 3%.
It is preferably 5% by weight, more preferably 0.5 to 10% by weight. 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 the content is 35% by weight or more, the viscosity of the liquid B tends to increase and the injection property into the rock tends to be poor.

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

First, the solution A and the solution B are separately pumped by separate pumps, mixed immediately before injection, and used as a stopper grout for backfilling a gap such as a tunnel.

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 in which two liquids can be mixed in a flow path is preferable. If the mixing is insufficient, the reaction between the liquid A and the liquid B becomes partial, and there is a possibility that sufficient foaming may not be performed.

Next, a construction method when the two-pack type polyurethane foam composition of the present invention is used as a stopper grout will be described.

Drilling and injection are performed at every support of about 1 m in the traveling direction of the tunnel. In addition, boring and injection are performed at 50 cm intervals in the inner circumferential direction of the tunnel.

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

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

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

As the infusion pump, it is preferable to use an air-driven or electric gear pump in terms of a pressure that can sufficiently cope with the infusion pressure.

The solution A and the solution B are separately fed under pressure, mixed and mixed immediately before injection into a tunnel or the like, and continuously mixed and injected using a shot mixer or the like.

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

[0045]

The present invention will be further described below with reference to 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 mixed. As shown, liquid rubber was added to obtain liquid A. An equal amount of the solution A and the solution B composed of polyisocyanate were mixed and reacted. Table 1 also shows the compounding amount of the added liquid rubber, the expansion ratio of the composition, and the shrinkage ratio of the foam molded product. In addition,
The shrinkage was measured as the volume shrinkage of a cylindrical foam molded product prepared in a 2,000 cc beaker at 25 ° C. for 7 days.

<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: Triethylene diamine manufactured by Mitsui Toatsu Co., Ltd. Catalyst b: Dibutyltin dilaurate manufactured by Nitto Kasei Co., Ltd. Foam stabilizer: Product name "L-3601" manufactured by Nitto Unicar Co., Ltd. Liquid rubber α : Polybutadiene manufactured by Idemitsu Petrochemical Co., Ltd.
oly bd R-45HT ”Liquid rubber β: Chloroprene manufactured by Denki Kagaku Kogyo Co., Ltd., product name“ LCR-FH050 ”Isocyanate: Mitsui Toatsu Co., Ltd. product name“ MDI-CR200 ”, NCO
Content 31-34% by weight

[0048]

[Table 1]

Example 2 A liquid was prepared by mixing 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. . B
As a liquid, 100 parts by weight of polyisocyanate,
Using a mixture of liquid rubber γ as shown in Table 2,
The procedure was performed in the same manner as in Example 1 except that the liquid was mixed in the same amount.
The results are also shown in Table 2.

<Materials Used> Liquid rubber γ: trade name “Poly bd MC-50” manufactured by Idemitsu Petrochemical Co., Ltd., obtained by diluting liquid rubber prepolymer obtained by reaction of liquid rubber α with isocyanate with dioctyl phthalate.

[0051]

[Table 2]

Example 3 The borehole was drilled 30 years ago by a blasting method and the circumference of a headrace tunnel of a private power plant of Denki Kagaku Kogyo Co., Ltd. was observed. . As a result, there was a gap of 10 to 40 cm between the concrete and the ground, and there was a large gap especially in the heavenly area. Also,
Many foreign substances were found in the fallen object and the support material in the ground.
A stopper grout zone was created by injecting two rows at 1 m intervals into the tunnel cross section. The injection holes were drilled every 50 cm. 70 parts by weight of polyol A, 20 parts by weight of polyol B,
A liquid 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 a foam stabilizer. Further, the liquid rubber γ is converted to an isocyanate and a liquid rubber γ.
Of 5 parts by weight with respect to 100 parts by weight of
The solution was mixed with an equal amount of the solution A. The expected void volume of the tunnel
30cm, using a two-part pump with an air pump and a gear pump, one place is the same as the expected void volume, one place is 1.
Five times the volume was injected, and one site was injected twice. In the calculation, the injection zone was set at 2 m in the lateral direction.

As a result, the whole amount was injected at the same amount as the expected void amount and 1.5 times the amount, but not at the double amount, the whole amount was not injected.
At 1.8 times the pressure was 15 kg / cm ² or more and injection was not possible. Drilling was performed every 50 cm in the tunnel to check the injection status. As a result of checking the injection status, the same amount as the expected void volume,
Both 1.5 times and 2 times injection were sufficiently injected, 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 location in the lower part of the tunnel, and up to 1.5 m in the heaven. In the case of a 1.5-fold injection, up to 2 m was observed in the lower part and up to 1 m in the heaven. Furthermore, with the same amount of injection, it was confirmed to 1.5 m in the lower part and 1 m in the heaven.

Thereafter, cement-bentonite grout was injected. All cement in the stopper grout
The bentonite grout stayed and did not flow out, and the backfilling of the tunnel could be reliably performed. In addition, the backfilled tunnel has no water leakage and has improved durability.

Example 4 The procedure of Example 3 was repeated, except that the backpacking injection with cement-bentonite grout was performed without injecting the two-part foamed polyurethane foam composition of the present invention.

As a result, this tunnel had insufficient concrete in the heavenly area, had continuous voids, and had a length of 6 km.
For this reason, even if cement-bentonite grout was injected, it flowed along the gradient of the tunnel, filling could not be completed forever, and integration with the ground could not be performed.

Example 5 A cement-water glass-based injection material having a gel time of 30 seconds was used as a stopper grout, and backfill injection with cement-bentonite grout was performed in the same manner as in Example 3.

According to the result of the boring, even if the injection amount twice as large as the expected amount of voids could not completely fill the porosity of the heaven, the cement-bentonite grout flowed out over a wide area and the heaven part was sufficiently removed. It could not be filled. Also, even when using a cement-based injection material consisting of quick-setting cement, similar to the cement-water glass-based injection material,
Sufficient filling was not possible.

[0059]

When the urethane foam composition of the present invention is used, a non-shrinkable foamed product having a high expansion ratio of about 40 times can be obtained, and not only small voids but also large voids of 1 m or more depending on the place. It can be filled completely and in a short time. In addition, the foamed urethane foam composition of the present invention is effective as a stopper grout since no void is formed again even after a long time has elapsed after the injection into the void in the ground. And since there is no shrinkage after hardening and the strength is strong, there is an effect that it can be injected alone for ground improvement and strengthening. Furthermore, since it is not a factor of the ground fluctuation and has a high expansion ratio, it has an effect of being able to compete with cement and other inexpensive inorganic fillers in terms of cost.

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Isao Terashima 2209 Aomi, Aomi-cho, Nishikubiki-gun, Niigata Inside the Aomi Plant of Electrochemical Industry Co., Ltd. Takeshi Sato, Examiner, Aomi Plant of Denki Kagaku Kogyo Co., Ltd. (56) References JP-A-2-298574 (JP, A) JP-A-2-55718 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08G 18/00-18/87 E02D 3/12 C09K 17/30

Claims (3)

(57) [Claims] 1. A liquid containing 0.05 to 35% by weight of a liquid rubber and containing a polyol liquid mainly composed of a primary polyol having two or more hydroxyl groups, a catalyst, a foaming agent, and a foam stabilizer. When, two-characterized by comprising the liquid B comprising a polyisocyanate polyurethane foam composition. 2. A liquid rubber prepolymerized with NCO and a liquid A containing a polyol liquid mainly composed of a primary polyol having two or more hydroxyl groups, a catalyst, a foaming agent and a foam stabilizer. A two-part foamed polyurethane foam composition comprising a liquid B containing a polyisocyanate containing 0.05 to 35% by weight of a polymer as a main component. 3. A liquid containing a polyol 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. And a reaction in the presence of a liquid rubber.