JPS63117088A - Sealant for water cutoff - Google Patents

Abstract

PURPOSE:To provide a sealant which has no toxicity and excellent handleability, exhibiting excellent water cutoff properties for a prolonged period of time and which comprises a soft polyurethane elastomer prepd. by mixing a urethane prepolymer having a particular isocyanate terminal with water. CONSTITUTION:A polyalkylene oxide contg. 20-60wt% prim. alkylene oxide units in its molecule, prepd. by polymn. of a prim. alkylene oxide and a sec. alkylene oxide, is reacted with an org. polyisocyanate, thereby preparing a urethane prepolymer (A) having an isocyanate terminal. The prepolymer (A) is mixed with water (B) in a wt. ratio of A to B of 1:0.3-5, thereby preparing a soft polyurethane elastomer. The sealant is comprised of this elastomer. With respect to the sealant, it is possible to blend filaments of an org. fiber inactive to isocyanate groups with the soft polyurethane elastomer, or to integrate, by lamination etc., a woven or non-woven fabric composed of the above org. fiber with the elastomer.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention provides 11! There is no need to worry about gender, and it is easy to handle.
Furthermore, the present invention relates to a water-stop sealing material that can exhibit water-stop performance over a long period of time.

(Prior art) Conventionally, for example, wire materials such as communication cables were installed.
Inside the room -: +a, ij direction ¥3 on the wall 4. Suga 1 each loga 1
A cable or the like is arranged to extend from one pipe port to the other pipe port so as to cross the manhole. The above pipe entrance is a conch 'J-1 formed underground.
! ii! ! This is the end of the pipe, and if water that has entered the pipe flows out from here, the inside of the manhole becomes flooded.

To prevent such flooding phenomena from occurring.

・Various sealing materials are used to seal and fill the gap between the inner circumferential surface of the R channel and the outer circumferential surface of the cable or other wire material inserted into the conduit to stop water.

Such sealing materials include water-curable urethane pret on base materials such as resin foam and organic fibers. IJ mom-impregnated products are known.

(Problems to be Solved by the Invention) However, since conventionally known sealing products are used by impregnating the above-mentioned base material with liquid urethane prepolymer, the mixing ratio of the base material and the prepolymer is adjusted. Since the prepolymer is in a liquid state, it is difficult to handle during work, and the prepolymer is toxic, which poses health and safety problems for workers.

Furthermore, the above-mentioned conventional C/L' products also have problems in terms of water-stopping performance. In other words, once the sealing material has foamed and hardened in contact with water, it shrinks once it becomes dry.
It can no longer function as a water stopper.

The present invention was invented based on these circumstances, and provides a sealing material that is free from toxicity, is easy to handle, and exhibits its full water-stopping performance for long periods of time. The purpose is to

(Means for solving the problems) The present invention provides I! & A urethane prepolymer containing terminal isocyanate groups obtained by reacting an organic polyisocyanate with a polyalkylene oxide obtained by copolymerizing an alkylene oxide and a secondary alkylene oxide and containing 20 to 60% by weight of primary alkylene oxide in 9 molecules. Add water (B) to (A) in a weight ratio of A:B=l:Q, 3~
The gist is a sealing material formed of a soft polycrethane elastomer obtained by mixing 5 parts.

The polyalkylene oxide used in the present invention has tM
This is a random copolymerization of k-alkylene oxide and secondary alkylene oxide. As the above 1fi alkyl oxide, ethylene oxide (EO)
is given.

This substance has high reactivity with incyanate and has a hydrophilic property.
do. Examples of secondary alkylene oxides include propylene oxide (PO), which is hydrophobic and less reactive with incyanate than primary alkylene oxides. In this case, the polyalkylene oxide h has 20 to 60 primary alkylene oxides.
It is necessary to set it so that the percentage of repeated traces is included. If it falls below the above range, the reactivity of the produced prepolymer with water becomes slow and the cured product becomes insoluble in water and loses water wettability.

Conversely, when the pupil circumference is exceeded, the reactivity of the prepolymer with water becomes faster, but the prepolymer has a high affinity with water and the cured product tends to exhibit solubility in water.

Water swelling property disappears. Therefore, it is necessary to set the content a & of the primary alkylene oxide within the above range.

As the organic polyisocyanate to be reacted with the above-mentioned polyalkylene and oxide, there are used tolylene diisocyanate (Tl) I), diphenylmemen diisocyanate I- (!1lDI), etc. which are commonly used in the production of polyurethane.

The urethane prepolymer described above may be used alone, but depending on the case, it may be used as a catalyst (to control the curing speed), a filler (to control the reinforcing property), or an effi/11 (to control the disassembly of the cured product). They can be used in combination, and a foaming ratio of 0 can also be selected arbitrarily.

The amount of water (B) to be mixed into the urethane prepolymer (A) is set at a weight ratio of A:B=170.3 to 50. The reason why the mixing ratio of water is limited to the above range is that the polyurethane produced by the reaction with the urethane prepolymer is a soft solid elastic body and has appropriate mechanical strength.
Moreover, it is made to have good water swelling properties. The preferred mixing ratio of water is A:B=l:o! 5～
3, and the polyurethane used under these conditions is a soft foam, which is formed into a tape or sheet form, and is wrapped around the outer circumferential surface of a wire material such as a cable by a predetermined amount, or wrapped in a hollow cylindrical shape. This is because it is used by making it into a wire rod and fitting it onto the outside of the wire rod.

There is no concern about toxicity, it is easy to handle, and has excellent casting properties.

1. In the sealing material of the present invention, inert m-fiber filaments with isocyanate groups are mixed into the obtained soft polyurethane elastomer.

Alternatively, woven fabrics or non-woven fabrics made of the above-mentioned organic fibers may be laminated or otherwise integrated.

(Effects of the Invention) The sealing material of the present invention is made into a soft solid elastic material by mixing a specific urethane prepolymer with a specific amount of water, so there is no need to worry about safety and health (toxicity). There is no need for adjustment work such as impregnating a base material such as a resin foam with a liquid prepolymer at a predetermined ratio as in the past, and it can be formed into an appropriate shape such as a tape shape or a hollow cylindrical shape.

The sealing material of the present invention only needs to be placed in a predetermined gap and is easy to handle.

Contains monoalkylene oxide on a specific surface, so even after it dries, it has excellent water swelling properties when it comes into contact with water leakage, so it prevents sagging over a long period of time. Demonstrates water performance.

(Example) The sealing material of the present invention is manufactured, for example, as follows. First, ethylene oxide (EO) and propylene oxide (PO) are randomly copolymerized under a polymerization catalyst,
Boria μ-kylene oxide (PAO) with different EO contents
).

Next, add tolylene diisocyanate (TDI) to this PAO.
) to synthesize a terminal isocyanate-based iurethane prebolimer.

Then, water is mixed in various proportions with this prepolymer,
Target polyurethane elastic body T-width 50#1lllX
A sheet-like sealing material with a thickness of 5 ns m is manufactured. The results are shown in Table-1.

Using the sh/’ goods obtained in this way.

Pipe entrance where bent water exists in a communication cable manhole (
Water was stopped for a pipe with an inner diameter of 75 mmφ and a cable outer diameter of 5 Q mmφ. The results regarding workability and water stop performance are shown in Table 2. 9 Sealing material of the present invention (width 5 Q
mm×thickness 5 mm) was wound eight times around the outer peripheral surface of the cape/L/ (wire rod) over an axial length of 5 Q mm from the open end of the conduit opening.

In addition, regarding water stop performance, initial performance and performance after drying (
40″QX168 Shima dry), water pressure 2Kp/d
Check to see if it can withstand.

Those that withstood this water pressure were marked as ○, and those that could not reach 1 m were marked as X in the table.

Note that the shape of the sealing material of the present invention is not only the above-mentioned flat sheet shape but also a hollow cylindrical shape.

It can also be used by fitting it on the outside of the cable, further improving handling properties.

In addition, when applying the 7-ru material of the present invention, it is an essential condition that water leakage exists at the location where conventional sealing materials should stop water (i.e.,

Conventional sealing materials immediately react with water leakage to form a foamed and cured material, thereby purifying the water. ), on the other hand, the presence of water leakage during construction is not necessarily essential, and it also has the characteristic of exhibiting excellent water-stopping performance by swelling when it comes into contact with leakage after casting.

Claims (1)

[Claims] Primary alkylene oxide and secondary alkylene oxide are polymerized to form two primary alkylene oxides in the molecule.
Water (B) is added to the terminal isocyanate group-containing urethane prepolymer (A) obtained by reacting an organic polyisocyanate with a polyalkylene oxide containing 0 to 60% by weight at a weight ratio of A:B=1:0.3. A water-stopping sealing material characterized by being formed of a soft polyurethane elastic material obtained by mixing at a ratio of 5 to 5.