JPH03197798A - Tail seal composition of shield excavator - Google Patents

Abstract

PURPOSE:To effectively cut off underground water penetration from the tail seal section of an excavator by setting the content of base oil, talc and fiber as a specific wt.%. CONSTITUTION:Talc 20-60wt.%, synthetic fiber having 1-15mm in length and/or natural fiber 0.5-10wt.% and synthetic fiber having the fiber length less than 1mm and/or natural fiber 0.5-10wt.% are mixed with base oil or grease to make a tail seal composition. A wirebrush and wire net are textured closely to promote the cutting-off operation under high water pressure.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a tail seal composition that stops groundwater from entering through the tail seal portion of a shield excavator that is subjected to high water pressure when excavating an underground tunnel. It is something.

[Prior art] Urban tunnels in urban areas are now becoming more and more complex, including large underground structures such as subways, underground shopping malls, and underground parking lots, as well as common ditches or tunnels for water, sewage, communications, electricity, gas, etc., and tunnels are becoming deeper. Ta. Along with this, construction methods have changed to tunnel construction methods, mainly shield construction methods.

A bending machine is used for bending in the tunnel construction method. In order to prevent water and dirt from entering the bending machine, a wire brush or a wire net is attached to the seal tail of the bending machine. However, in the case of deep underground or on the seabed, it is difficult to completely stop water by using the brush or net alone due to high water pressure.

Therefore, a sealant made by mixing grease with a polymeric water-absorbing and expanding agent (181E!98, 1987) is used for the wire brush or wire net of the seal tail, and a sealant made by mixing pigment, metal, and synthetic resin with grease. (Unexamined Japanese Patent Publication No. 63
-315798) and hydrocarbon oil mixed with liquid resin, asbestos, and synthetic fibers (Japanese Patent Application Laid-Open No. 62-190280) to improve the water-stopping effect. There is.

However, these former two types of sealants are still insufficient in water purifying effect for use at high depths, and the third type has a safety problem because it contains asbestos as an essential component.

[Problems to be Solved by the Invention] The present inventor has focused on the fact that by mixing cut fibers, the cut fibers become entangled with wire brushes and wire nets, thereby promoting the effect of the cut fibers becoming entangled with wire brushes and wire nets, and have attempted to overcome the drawbacks of the above-mentioned sealants. As a result of our research, we found that by combining long and short fibers and talc and entwining them in the order of long fibers, short fibers, and talc, wire brushes and wire nets were made into dense structures, resulting in a sealant with a higher sealant than conventional sealants. It was discovered that the water-stopping effect under water pressure was improved, and the present invention was completed.

SUMMARY OF THE INVENTION An object of the present invention is to provide a tail seal composition that promotes the adhesion retention effect of a sealant on wire brushes and wire nets in the tail seal portion of an excavator.

[Means for Solving the Problems] That is, the present invention provides: (1) 20 to 60% by weight of talc, based on the total amount of the composition, to the base oil or grease; (3) fiber length of 1 to 60% by weight;
15mm synthetic and/or natural fibers
0.5 to 10% by weight, and (2) 0.5 to 10% by weight of fiber length ll1lII + ungrooved synthetic fiber and/or natural fiber as essential components. It is something that provides something.

Hereinafter, the tail seal composition according to the present invention will be explained in detail.

(1) Mineral oil is preferably used as the base oil. As the mineral oil, a lubricating oil fraction is usually used. For example, the lubricating oil fraction obtained by atmospheric distillation of mineral oil may be subjected to appropriate processes such as solvent film scraping, solvent extraction, hydrocracking, solvent film waxing, hydrogenation film waxing, sulfuric acid washing, clay refining, and hydrorefining. They are used in combination and purified. Although synthetic oils such as poly-alpha olefins, alkylbenzenes, esters, and polyethers can also be used, it is economically preferable to use mineral oils. The viscosity range of the base oil is not particularly limited, but any viscosity range of commonly used lubricating oils can be used. Among them, the preferred viscosity range is 40'C and 6 to 1000 cSt can be used optimally. On the other hand, grease is a mixture of the above base oil and a thickener, and the types of thickeners include metal soaps such as lithium soap and calcium soap, composite soaps, and non-B soaps such as bentone and urea. Any of these may be used, but metal soap thickeners such as lithium soap and calcium soap are preferred in terms of economy. The amount of the thickener is not particularly limited, and is appropriately determined depending on the amount of talc and (3) small fibers and consistency, but is usually 5% by weight or less based on the total amount of the grease. The oil retention properties of the tail seal composition are better when grease is used.

(2) Talc is mixed in an amount of 20 to 60% by weight, preferably 30 to 50% by weight, based on the total amount of the composition. If the groove is not 20% by weight, the desired water pressure resistance cannot be obtained, and 6
If it exceeds 0% by weight, the tail seal composition becomes brick-like, which is not preferable. The particle size of talc is not particularly limited, and for example, a particle size having an average particle size in the range of 5 to 50 μm may be used.

(3) (Φ fibers include polyolefin (polyethylene, polypropylene, etc.), polyamide (nylon, etc.), polyvinyl alcohol (vinylon, etc.), rayon, acetate, polyester (polyethylene terephthalate, etc.), polyacrylic (polyacrylonitrile, etc.), Among synthetic fibers such as vinyl chloride and polyvinylidene chloride, and natural fibers such as cotton thread, silk, wool, and linen, fiber length is 1.
~151111s Preferably, fibers with a length of 2 to 10 mm (hereinafter referred to as long fibers) and fiber lengths of less than 1ff111 to 0,001 mm (hereinafter referred to as short fibers) are used, and among long fibers and short fibers, One type or multiple types can be used. The thickness of these fibers is not particularly limited, but is preferably 0.5 to 20
Something in the denier range is best.

The content of both long fibers and short fibers is 0 based on the total amount of the composition.
．． 5 to 10% by weight, preferably 1 to 6% by weight, respectively.
Weight%. Either long fiber or short fiber is 0.5
If the content is less than 10% by weight, the desired water pressure resistance cannot be obtained, and if the content of either long fibers or short fibers exceeds 10% by weight, the pumpability will be impaired.

Mix the ingredients of (1) to ■ above with a normal mixer,
Usually, the consistency is adjusted to 200 to 350, preferably 250 to 310. If the consistency is less than 200, the pumping performance will be impaired, and if it is greater than 350, the desired water resistance will not be obtained. In addition, by incorporating talc, the specific gravity of this tail seal composition can be made higher than that of water, eliminating the problem of the sealant floating when underground water enters, which often occurs with conventional grease-based sealants. . Specific gravity is preferably 1
．． 2 to 2.0, and if this is not possible, inorganic substances such as calcium carbonate, calcium sulfate, magnesium carbonate, barium carbonate, barium sulfate, and zinc oxide may be added.

It goes without saying that in addition to each of the compositions described above, various colorants, antioxidants, rust inhibitors, etc. may be mixed.

[Examples] The content of the present invention will now be explained in more detail with reference to Examples and Comparative Examples.

Real JLLL2J- Mineral oil (040℃, lowest), rayon with a thickness of 5 denier and a length of 1 to 9 mm, a thickness of 1 denier and a length of lnv
A predetermined amount of ungrooved cotton yarn and talc having an average particle size of 9.21 were mixed to obtain a tail seal composition having the composition shown in Table 1.

Actual JL Example": 2" - A base grease was synthesized from mineral oil (040°C, 485 cSt) and lithium 12-hydroxystearate, and this was coated with nylon having a thickness of 3 deniers and a length of 2 to 8 cm, and a thickness of 0.
5 denier, length 1■ ungrooved tetron and average grain size 3
A predetermined amount of 3.5j1 m of talc was mixed to obtain a tail seal composition having the composition shown in Table 1.

For comparison, rayon with a thickness of 5 denier and a length of 1 to 9 mm, cotton thread with a thickness of 1 denier and a length of less than 1 ma, and an average particle size of 9 in mineral oil (040 ° C 1100 cSt) for comparison. .2μm
A mixture of only one component of talc (Comparative Examples 1 to 3)
3) Base grease obtained from mineral oil (040°C, 485C5t) and lithium 12-hydroquine stearate (
Comparative Example 4), the grease had a thickness of 3 denier and a length of 2 to 8
IllIl nylon, thickness 0.5 denier, length 1■
The compositions of mixtures of only two components of ungrooved Tetron and talc with an average particle size of 33.5 μm (Comparative Examples 5 to 7) and two types of commercially available sealants (Comparative Example 8.9) were also investigated. It is shown in Table 1.

The following evaluation tests were conducted on these tail seal compositions, and the results are also shown in Table 1.

<Evaluation test> 1. Penetration Worked penetration (Bow) according to JIS K22205.3
It was measured in accordance with the consistency test method.

2. Water pressure test Figure 1 shows an overview of the water pressure test equipment.

Ten pieces of wire mesh of 20 mesh are fixed to the bottom of a cylindrical metal container, and the tail seal composition is injected to a layer thickness of 50 mesh. 50cc of water is sealed on top of it, and the nitrogen pressure is 30 kgf.
/cm'' for 10 minutes, and then the amount of the tail seal composition that protruded from the wire mesh was measured.

[Effects of the Invention] As is clear from the results shown in Table 1, all of the tail seal compositions according to the present invention exhibit excellent performance, with a small amount of leakage in the water pressure test. On the other hand,■
-(4) Compositions lacking one or two components (Comparative Examples 1 to 7) and commercially available sealants (Comparative Example 8.
In case 9), the amount of leakage was large or the wire mesh broke, and the performance was clearly inferior to that of the composition of the present invention.

As detailed above, the tail seal composition of the present invention has
It is a composition with excellent water purifying action under high water pressure.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an outline of a water pressure test apparatus used in Examples and Comparative Examples. Applicant: 1 person outside Nippon Oil Co., Ltd.

Claims (1)

[Scope of Claims] The following four components: (1) Base oil or grease, based on the total amount of the composition, (2) 20 to 60% by weight of talc, and (3) synthetic fibers and/or natural fibers with a fiber length of 1 to 15 mm. A tail seal composition for a shield excavator, characterized in that it contains as essential components 0.5 to 10% by weight of fibers, and (4) 0.5 to 10% by weight of synthetic fibers and/or natural fibers with a fiber length of less than 1 mm. thing.