JPWO2016063900A1 - Softener for tail seal of shield machine - Google Patents

Abstract

A softener for a tail seal composition for shield machine and a tail seal composition to which this softener is added, even if a backing agent penetrates into the brush seal portion of the tail seal composition I will provide a. An additive for a tail seal composition for a shield machine containing a hydrocarbon base oil, a thickener and a fiber, which is selected from esters of a chain carboxylic acid and a chain alcohol A softener for tail seals of shield machine including one or more selected from the above-mentioned esters, and [A] 10 to 70% by mass of lubricant base oil consisting of hydrocarbon, [B] increase A tail seal composition for a shield machine containing 30 to 80% by weight of a funnel, [C] 1 to 20% by weight of a fiber, and [D] 0.2 to 20% by weight of the ester.

Description

  The present invention relates to a tail seal softener for a shield machine and a tail seal composition for a shield machine to which this is added.

When excavating a tunnel into the ground with a shield machine, the shield machine advances while excavating ground in the direction of travel, and segments behind the shield machine are sequentially assembled as the inner wall of the tunnel. ing. In this case, the outer diameter of the tunnel to be excavated (excavation opening diameter) is the outer diameter of the shield machine, but since the segment is assembled inside the shield machine, the outer diameter of the segment is less than the inner diameter of the shield machine. Become. For this reason, a gap is formed between the outer diameter of the tunnel and the outer diameter of the segment behind the shield machine, and this gap is filled with a backing agent as the shield machine advances.
On the other hand, in the tunnel at the rear end of the shield machine that has not yet been filled with the backfilling agent, groundwater and the like have infiltrated, and in order to prevent this groundwater from entering the shield machine, the shield machine A plurality of rows of brush seals for stopping water between the outer circumference of the segment in the shield machine and the inner circumference of the shield machine are provided on the inner circumference of the shield machine. And in order to maintain the water stop, a tail seal composition is filled between these brush seals (see, for example, Patent Document 1).

As this tail seal composition, a mixture of mineral oil-based or synthetic-based lubricating base oil and scale-like thickener, other inorganic fillers, organic powder, fiber, etc. is used (patent) References 1-4).
By the way, since the backing agent has high fluidity at the beginning of filling and then solidifies, the backing agent with high fluidity penetrates into the brush seal part at the rear end of the shield machine, the brush seal and the segment are fixed, and the shield machine It is difficult to move forward, and depending on the strength of the segment, the segment is destroyed. For this reason, there has been a demand for a method in which the brush seal and the segment do not adhere even if the backing agent enters the brush seal portion.

Japanese Patent Publication No. 7-6350 JP-A-5-187194 JP-A-7-109893 Japanese Patent Laid-Open No. 9-208943

  The present invention solves the above-described problems. For a tail seal composition for a shield machine, a brush seal and a segment are difficult to adhere even if a back-filling agent enters the brush seal portion of the tail seal composition. A softener and a tail seal composition to which the softener is added are provided.

  As a result of diligent research to solve the above problems, the present inventors have surprisingly maintained water-stopping properties by adding an ester having a specific structure to a tail seal composition containing a fibrous material or the like. As it is, it has been found that even if the back-filling agent is mixed, it is not cured.

The present invention has been made based on such findings and is as follows.
(1) An additive for tail seal composition of a shield machine containing a hydrocarbon base oil, a thickener and a fiber, which is selected from esters of a chain carboxylic acid and a chain alcohol. A softener for tail seals of a shield machine comprising at least one selected from the group consisting of one or more selected from the esters.
(2) The tail seal of the shield machine according to the above (1), wherein the ester is an ester of a chain monovalent carboxylic acid (fatty acid) having 4 to 40 carbon atoms and a chain alcohol having 3 to 10 carbon atoms. Softener.
(3) The tail seal softener for a shield machine according to (1), wherein the number of hydroxyl groups remaining in the ester is 1 or less per molecule.
(4) [A] 10 to 70% by mass of a lubricant base oil composed of hydrocarbon, [B] 30 to 80% by mass of thickener, [C] 1 to 20% by mass of fiber, and [D] above ( A tail seal composition for a shield machine, containing 0.2 to 20% by mass of one or more esters according to 1) to (3).

The softener of the present invention is added to a tail seal composition containing a lubricant base oil composed of hydrocarbons, a thickener and a fiber, and when a backing agent is mixed, it is softened. There is an extraordinary effect that sticking between the brush seal and the segment can be suppressed.
Further, the tail seal composition for a shield machine according to the present invention can be efficiently excavated by a shield machine in order to soften and prevent sticking between the brush seal and the segment even when a backing agent is mixed. There is a special effect that you can.

The softener of the present invention softens the tail seal composition mixed with the backing agent and delays the setting of the backing agent, and contains an ester of a chain carboxylic acid and a chain alcohol as an active ingredient. .
The chain carboxylic acid constituting the ester has a structure in which at least one hydrogen of the chain hydrocarbon is substituted with a carboxyl group, and preferably has a carboxyl group at the terminal. 4-40 are preferable, as for carbon number of this carboxylic acid, 8-35 are more preferable, and monovalent carboxylic acid (fatty acid) is preferable. The chain carboxylic acid may be saturated or unsaturated, and may be linear or branched. Moreover, the hydroxy fatty acid by which some hydrogen was substituted by the hydroxyl group may be sufficient. A single compound or a mixture of a plurality of compounds may be used.
The chain alcohol constituting the ester has a structure in which at least one hydrogen of the chain hydrocarbon is substituted with a hydroxyl group (OH group), and preferably has a hydroxyl group at the terminal. The number of carbon atoms is preferably 2 to 12, and may be monovalent or divalent or higher polyhydric alcohol (polyol), but divalent to tetravalent polyhydric alcohol is more preferred. This chain alcohol may be saturated or unsaturated, and may be linear or branched. As for the carbon number, 3-10 are more preferable. Further, it may be a single compound or a mixture of a plurality of compounds.

The ester of the present invention may be a full ester in which all hydroxyl groups form ester bonds, or a partial ester in which some hydroxyl groups do not form ester bonds. A full ester or a partial ester in which the number of OH groups remaining in the ester is 1 or less per molecule is more preferred.
These esters may be used alone or in combination of two or more.
The softening agent of the present invention may use the ester as it is as a softening agent, or may be one obtained by dissolving or dispersing the ester in an organic solvent or the like. In this case, the organic solvent is not particularly limited as long as it is a variety of hydrocarbon solvents compatible with the lubricating base oil in the tail seal composition, and the lubricating base oil used for the tail seal is used as the solvent. Is more preferable. The content of the ester in the softening agent is preferably 50% by mass or more from the viewpoint of the addition efficiency, and it is more preferable to use the ester as it is as a softening agent.
In addition to the above-mentioned esters, this softener is generally used as a lubricant, grease, etc., as necessary, as a detergent, dispersant, antiwear agent, antioxidant, rust inhibitor, corrosion inhibitor. An agent or the like can be added as appropriate.

  The softener of the present invention is added to a tail seal composition for a shield machine containing a lubricant base oil composed of hydrocarbon, a thickener, and a fiber. The addition amount is preferably 0.2 to 20% by mass, more preferably 0.5 to 15% by mass, and more preferably 0.5 to 15% by mass based on the total amount of the tail seal composition. 7-10 mass% is further more preferable.

The tail seal composition for a shield machine according to the present invention comprises: [A] 10 to 70% by mass of a lubricant base oil composed of hydrocarbon, [B] 30 to 80% by mass of a thickener, [C] 1 to 20 of fibrous material. Mass% and [D] 0.2-20 mass% of ester of chain carboxylic acid and chain alcohol is contained. The composition preferably has a density of 1.1 to 1.8 g / cm ³ at 15 ° C. for ease of pumping, water-stopping, stability when mixed with water, and oil retention at high temperatures. 1.1 to 1.5 g / cm ³ is more preferable, and 1.1 to 1.4 g / cm ³ is more preferable. For the same reason, those having an immiscibility consistency of 150 to 350 are preferred, and 220 to 280 is more preferred. In addition, the measurement of the immiscible penetration referred to in the present invention is based on a method based on JIS K2220.
Furthermore, it is preferable that the tail seal composition for a shield machine of the present invention is substantially free of moisture. The fact that it does not substantially contain water means that it does not exclude water inevitably mixed in, but the water content is preferably 5% by mass or less based on the total amount of the tail seal composition, More preferably, it is 1 mass% or less.

[A] Lubricating oil base oil The lubricating oil base oil of the present invention may be any of mineral oils, synthetic oils or mixtures thereof as long as it is a lubricating oil base oil composed of hydrocarbons used in ordinary lubricating oils. Can do.
The physical properties of the lubricating base oil, kinematic viscosity at 40 ℃ is 100~3000mm ² / s, particularly preferably from 550~1500mm ² / s. Further, the pour point is preferably 0 ° C. or lower, and the flash point is preferably 150 ° C. or higher from the viewpoint of safety.
The content of the lubricating base oil is 10 to 70% by mass based on the total amount of the composition, preferably 15 to 60% by mass, more preferably 25 to 58% by mass, and still more preferably 35 to 57% by mass. %.

Mineral oil base oils are generally based on lubricating oil fractions obtained by distilling crude oil at atmospheric pressure or further distilling distillate oil obtained by distillation under reduced pressure through various refining processes. It can be prepared as it is or by blending various additives. The refining process includes hydrorefining, solvent extraction, solvent dewaxing, hydrodewaxing, sulfuric acid washing, clay treatment, etc., and these are combined in an appropriate order for treatment to obtain a mineral oil system suitable for the present invention. A lubricating base oil can be obtained. A mixture of a plurality of refined oils having different properties obtained by using different crude oils or distillate oils in different process combinations and sequences can also be used as a suitable base oil.
This mineral oil base oil preferably has an aromatic content of 20% or less from the viewpoint of handling safety.

Examples of the synthetic lubricating base oil composed of hydrocarbons include poly-α-olefin (PAO), low molecular weight ethylene / α-olefin copolymer, and high molecular weight polymer alkylnaphthalene such as polybutene and polyisobutene. These can be used alone or in combination.
An ester-based synthetic lubricating oil composed of an ester of a chain carboxylic acid and a chain alcohol is unsuitable as a lubricating base oil because it softens more than necessary due to the incorporation of a backing agent, resulting in a decrease in water stoppage and the like. It is.

[B] Thickener As the thickener of the present invention, it is preferable to use an inorganic powder in order to improve the water-stopping property of the tail seal composition. Examples of the inorganic powder in this case include oxides such as silicon, aluminum, magnesium, and calcium, hydroxides, carbonates, sulfates, and the like, and also a mixture thereof and a natural product. Ore powders containing these compounds as main components can also be used. Specifically, powders such as calcium carbonate, talc, calcium carbonate, magnesium carbonate, calcium sulfate, aluminum hydroxide, magnesium oxide, calcium oxide, aluminum oxide, silica, bentonite, and diatomaceous earth are suitable. These inorganic powders may be used alone or as a mixture of a plurality of types.
The inorganic powder preferably has an average particle size of 0.5 to 500 μm, more preferably 5 to 50 μm.

In addition, in order to adjust the tail seal composition to a suitable consistency for pumping, it is preferable to use a thickener used in ordinary lubricants and greases in combination. As the thickener used in the grease or the like, a metal soap, urea, or organic polymer is suitable.
In the metal soap thickener, the carboxylic acid may be an aliphatic carboxylic acid such as stearic acid or azelaic acid, or an aromatic carboxylic acid such as terephthalic acid, in particular, a monovalent or divalent aliphatic carboxylic acid, carbon The thing of aliphatic carboxylic acid of several 6-20 is preferable. The metal may be an alkali metal such as lithium or sodium, an alkaline earth metal such as calcium, or an amphoteric metal such as aluminum, but is preferably an alkali metal, particularly lithium. Such carboxylic acid metal salts may be used singly or in combination.

  As the urea-based thickener, a diurea compound obtained by reaction of diisocyanate and monoamine, a polyurea compound obtained by reaction of diisocyanate and monoamine, diamine, and the like are suitable, and as an organic polymer thickener, PTFE (polytetrafluoroethylene) and the like are suitable. In addition, the above-mentioned thickeners such as metal soap, urea, and organic polymer may be used alone or in combination of two or more.

  The content of these thickeners is 30 to 80% by mass as a total amount based on the total amount of the tail seal composition, but is preferably 35 to 75% by mass, and preferably 35 to 60% by mass in the inorganic powder. More preferred. The content of the metal soap, urea and organic polymer thickeners used in combination is preferably 35% by mass or less, more preferably 0.5 to 20% by mass, based on the total amount of the tail seal composition.

[C] The fibrous fiber is entangled with the metal net and brush bundled with the metal wire in the tail seal part of the shield machine, and forms a filter cloth layer with water-stopper together with lubricant base oil and thickener. Used for.
As the fiber, any of naturally-derived or organically-synthesized organic fibers can be used. For example, naturally-occurring natural fibers include cellulose and cotton fibers, and synthetic fibers include polypropylene and polyester. Is preferred.
This fiber has an average length of preferably 10 mm or less, more preferably 0.1 to 8 mm, and even more preferably 0.5 to 6 mm. The thickness is preferably 10 to 100 μm on average, and more preferably 15 to 90 μm.
The fiber content is 1 to 20% by mass based on the total amount of the tail seal composition, preferably 2 to 15% by mass, and more preferably 3 to 10% by mass.

[D] Ester The ester of the chain carboxylic acid and the chain alcohol of the present invention is the same as that described above as the active ingredient of the softener.
The content of this ester is 0.2 to 20% by mass based on the total amount of the tail seal composition, preferably 0.5 to 15% by mass, and more preferably 0.7 to 10% by mass.

[E] Other Additives In addition to the above components, the tail seal composition of the present invention includes, as necessary, detergents, dispersants, antiwear agents, oxidation agents, which are generally used in lubricating oils and greases. Inhibitors, rust inhibitors, corrosion inhibitors, and the like can be added as appropriate.

Using the following lubricant base oil, thickener, fiber, and ester, mix in the proportions (mass%) shown in Tables 1 and 2 to prepare tail seal compositions and measure the immiscibility penetration did. The results are shown in Tables 1 and 2.
[Components of tail seal composition]
A. Lubricating base oil Base oil A1: Mineral oil (manufactured by JX Nippon Oil & Energy, solvent refined heavy oil, density at 15 ° C .; 0.90 g / cm ³ )
Base oil A2: polybutene, average molecular weight; 15,000
Tables 1 and 2 show the kinematic viscosity (mm ² / s) at 40 ° C. when polybutene A2 is mixed with the mineral oil A1.
B. Thickener Thickener B1: Talc, average particle size; 20 μm
Thickener B2: calcium carbonate, average particle size; 10 μm
Thickener B3: Li stearic acid soap (reagent manufactured by Kanto Chemical Co., Inc.)

C. Fiber Fiber C1: Cotton fiber, average length: 1.8 mm, average diameter: 18 μm
Fiber C2: Polystyrene terephthalate fiber, average length: 5 mm, average diameter: 20 μm
Fibrous C3: cellulose fiber, average length: 3.0 mm, average diameter: 43 μm
D. Ester Ester D1: ester obtained from lanolin-derived fatty acid and pentaerythritol Ester D2: ester obtained from lanolin-derived fatty acid and trimethylolpropane Ester D3: ester obtained from isostearic acid and neopentyl glycol Ester D4: oleic acid and penta Ester obtained from erythritol Ester D5: Ester obtained from oleic acid and trimethylolpropane Ester D6: Ester obtained from 2-ethylhexanoic acid and pentaerythritol Ester D7: Butyl stearate Ester D8: Sorbitan monooleate

[Evaluation of Tail Seal Composition 1: Water Resistant]
A water pressure resistance test was performed under the following conditions to measure the presence or absence of effluent water.
A stainless steel pressure vessel having an inner diameter of 52 mm and a total of 16 openings (diameter 3 mm) having a center interval of 5 mm and 4 rows vertically and horizontally was used at the center of the bottom. A stainless steel mesh (No. 50, thickness 0.85 mm) was placed on the opening, and 50 g of the tail seal composition prepared above was introduced. Water (10 g) was placed on the tail seal composition, pressurized with air at a pressure of 35 kgf / cm ² for 5 minutes, and the water stoppage was evaluated by the presence or absence of water outflow from the bottom opening. The results are shown in Tables 1 and 2.
As a result, it can be seen that Comparative Example 5 containing no fiber has no water-stopping property.

[Evaluation of Tail Seal Composition 2: Initial Softening Property]
100 g of the tail seal composition prepared above, quick-drying cement (product of Toyo Materan, trade name instant cement (30-minute quick-drying)) which is the main component of the backing material, and 15 g of water are mixed by hand before mixing. The initial softening property of the mixture was evaluated by measuring the difference between the consistency of the tail seal composition of No. 1 and the consistency immediately after mixing. The results are shown in Tables 1 and 2. Mixing the tail seal composition with quick-drying cement and water will soften and increase the consistency of the tail seal composition before mixing, but if this difference is large, it will take time to cure and harden to solidify. Indicates.
As a result, the compositions of Examples 1 to 12 containing the ester of the present invention did not contain an ester, or compared to Comparative Examples 1 to 4 containing an ester other than the ester of the present invention, It can be seen that it has the effect of softening the degree.

The tail seal softener of the present invention is added to the tail seal composition so that it can be softened even if a back agent entering the brush seal portion of the shield machine tail is mixed, so that the brush seal and the segment Since sticking can be suppressed, it is useful as a tail seal composition for a shield machine.
Further, since the tail seal composition of the present invention is softened when the back-filling agent is mixed and can suppress the sticking between the brush seal and the segment, it can efficiently perform excavation by the shield machine, Useful for excavators.

Claims (4)

  An additive for a tail seal composition for a shield machine containing a hydrocarbon base oil, a thickener and a fiber, which is selected from esters of a chain carboxylic acid and a chain alcohol A softener for tail seals of a shield machine comprising one or more selected from the above-mentioned esters.   The softener for tail seals of a shield machine according to claim 1, wherein the ester is an ester of a chain monovalent carboxylic acid (fatty acid) having 4 to 40 carbon atoms and a chain alcohol having 3 to 10 carbon atoms.   The softener for tail seals of a shield machine according to claim 1, wherein the number of hydroxyl groups remaining in the ester is 1 or less per molecule. [A] 10 to 70% by mass of a lubricating base oil composed of hydrocarbons,
[B] 30-80% by weight of thickener,
[C] 1-20% by mass of fiber, and
[D] 0.2 to 20% by mass of one or more esters according to claims 1 to 3
A tail seal composition for a shield machine containing