JP7744768B2 - Segment piece, manufacturing method for segment piece, and segment wall - Google Patents

Description

The present invention relates to segment pieces used in shield tunnel linings, a segment piece manufacturing method, and a segment wall.

In addition to mountain tunnels and undersea tunnels, for underground roads in urban areas, railway tunnels, sewer tunnels, underground river tunnels, and other structures where construction at shallow depths is difficult, the shield method is used, in which a shield machine is used to excavate the tunnel, and then segment pieces with a fan-shaped cross section, called segment pieces, are connected vertically and horizontally within the excavated tunnel to construct the tunnel.

Whether the space inside a tunnel is used as a road or railway, or as a storm waterway or sewer, there is a difference in the water pressure and earth pressure caused by groundwater or mud acting on the inside and outside surfaces of the tunnel wall, which acts as a boundary. Therefore, the waterproofing structure of the tunnel wall is an important issue when considering the cost of preventing water leakage after completion and the impact on the environment.

For this reason, efforts have been made in recent years to improve the waterproofing of the segment body.
For example, Patent Document 1 discloses a technique for attaching and installing a waterproofing material to the inner surface of the steel shell facing the concrete in order to improve the waterproofing performance between the different materials, the steel shell and the concrete, of a composite segment.

The technology described in Patent Document 1 allows the waterproofing function of the composite segment body to be maintained for a long period of time, and by increasing the restraining force between the steel shell and concrete, it becomes possible to prevent cracks in the concrete that can occur due to earthquakes, etc.

By the way, shield machines used in tunnel construction are equipped with multiple wire brushes called tail brushes at the rear (tail) of the machine to prevent groundwater and mud seeping from the mountain from flowing into the excavated tunnel. A pump continuously pressurizes grease into and between these brushes, filling them with grease. The grease-filled brushes then pass over the surface of the segments at low speed and with a heavy load, preventing water from entering the tunnel when the segments are connected. In other words, in tunnel construction using the shield method, the tail brushes pass over the outer surfaces of the segments with great pressure before the segments are connected to form the tunnel walls, so the outer surfaces of the segments need to be able to withstand abrasion caused by the strong force of the tail brushes.

Japanese Patent Application Laid-Open No. 2019-157622

Groundwater contains corrosive factors such as chloride ions, which are thought to cause neutralization of underground concrete or corrosion of the steel shell, leading to deterioration of the tunnel over time. For this reason, the segment pieces that form the shield tunnel must remain waterproof even after being subjected to loads from the tail brush.

The objective of the present invention is to propose segment pieces, a segment piece manufacturing method, and a segment wall body that are highly waterproof and have high-pressure scratch resistance that can withstand wear caused by the tail brush of a shield machine.

The inventors have thoroughly investigated the above-mentioned issues. As a result, they have discovered that rather than applying repair paint to tunnels already in service to extend their lifespan, applying a thick layer of liquid pre-coat paint to the surfaces of the segment pieces before they are connected, and then covering them with an organic resin coating that acts as a waterproof membrane, is ultimately effective in extending the lifespan of tunnels.

That is, the present invention relates to a segment piece, a method for manufacturing a segment piece, and a segment wall body, including the following aspects.
(1) A segment piece for forming a shield tunnel by connecting a plurality of segments in the circumferential and axial directions,
the segment piece has an outer surface portion that forms the outer surface of the shield tunnel on the natural ground side, an inner surface portion that faces the outer surface portion and forms the inner surface on the tunnel space side, and a side surface portion that connects the periphery of the outer surface portion and the inner surface portion,
At least a portion of the surface of the segment piece before connection is coated with an organic resin coating film having a film thickness of 100 μm to 5000 μm, which is formed from a liquid precoat paint (A) containing an organic resin component, a color pigment, an extender pigment, and a solvent.
(2) The segment piece according to (1), wherein at least the surface of the outer surface portion of the segment piece is coated with the organic resin coating film.
(3) The segment piece according to (1) or (2), wherein the segment piece comprises a steel shell having a steel plate covering at least the outer surface thereof and the steel shell is filled with concrete, and at least a part of the surface of the steel shell is painted with a liquid precoat paint (A).
(4) The segment piece according to any one of (1) to (3), wherein the organic resin component contained in the liquid precoat paint (A) includes an acrylic resin.
(5) The segment piece according to any one of (1) to (4), wherein the liquid precoat paint (A) is a one-component reactive curing type at room temperature.
(6) The segment piece according to any one of (1) to (5), wherein the liquid precoat paint (A) is a water-based paint.
(7) The segment piece according to any one of (1) to (6), wherein the liquid precoat paint (A) further contains at least one selected from a crosslinking agent, organic particles, inorganic particles, a lubricant, and a film-forming aid.
(8) The segment piece according to any one of (1) to (7), wherein an epoxy resin coating film is provided under the organic resin coating film.
(9) A segment wall body formed by connecting a plurality of segment pieces according to any one of (1) to (8).
(10) A method for manufacturing segment pieces for forming a shield tunnel by connecting a plurality of segment pieces in the circumferential direction and the axial direction, comprising the steps of:
the segment piece has an outer surface portion that forms the outer surface of the shield tunnel on the natural ground side, an inner surface portion that faces the outer surface portion and forms the inner surface on the tunnel space side, and a side surface portion that connects the periphery of the outer surface portion and the inner surface portion,
A method for producing a segment piece, comprising: applying a liquid precoat paint (A) containing an organic resin component, a color pigment, an extender pigment, and a solvent to at least a portion of the surface of the segment piece before the segment is connected, so that the dry film thickness is 100 μm to 5000 μm.
(11) A method for manufacturing segment pieces for forming a shield tunnel by connecting a plurality of segment pieces in the circumferential direction and the axial direction, comprising the steps of:
the segment piece has an outer surface portion that forms the outer surface of the shield tunnel on the natural ground side, an inner surface portion that faces the outer surface portion and forms the inner surface on the tunnel space side, and a side surface portion that connects the periphery of the outer surface portion and the inner surface portion,
A method for producing a segment piece, comprising: applying a liquid precoat paint (A) containing an organic resin component, a color pigment, an extender pigment, and a solvent to at least the outer surface of the segment piece before the segment is connected, so that the dry film thickness is 100 μm to 5000 μm.
(12) The segment piece is formed by filling a steel shell with concrete and having a steel plate covering at least an outer surface thereof,
(12) The method for manufacturing a segment piece according to (11), further comprising painting a liquid precoat paint (A) on at least a part of the surface of the outer surface of the steel shell after the steel shell is completed and before concrete is poured into the steel shell.
(13) The segment piece is formed by filling a steel shell with concrete and having a steel plate covering at least an outer surface thereof,
(12) The method for manufacturing a segment piece according to (11), comprising, after pouring concrete into the steel shell, painting at least a part of the surface of the outer surface of the steel shell with a liquid precoat paint (A).
(14) The manufacturing method of a segment piece according to (13), wherein the outer surface of the steel shell is provided with a pouring hole for filling with concrete, and concrete is poured into the pouring hole with the outer surface of the steel shell facing upward.
(15) The method for manufacturing a segment piece according to any one of (10) to (14), further comprising a step of applying an epoxy resin paint before applying the liquid precoat paint (A).

The segment piece of the present invention is both resistant to high-pressure damage and waterproof, and therefore maintains its waterproof properties for a long period of time even after the tail brush of the shield machine passes through the segment piece with great force during tunnel construction using the shield method, thereby extending the life of the tunnel.
In particular, according to the first invention, by covering the segment pieces with a thick resin coating, the flexibility of the thick coating can be fully utilized against various impact loads that may be expected during construction, minimizing damage caused by these loads and making it possible to maintain a high-quality waterproofing film.
In particular, according to the second invention, by covering the outer surface of the segment piece with a thick resin coating, the flexibility of the thick resin coating allows the coating to appropriately follow the movement of the tail brush, even when subjected to the load that attempts to peel off the coating when the tail brush passes, which poses a particularly high risk of damage during construction.This makes it possible to minimize damage caused by the tail brush and more efficiently maintain a high-quality waterproofing film.
In particular, according to the third invention, by further covering the steel plates that cover the outer surfaces of the segment pieces with a thick resin coating, it is possible to prevent the occurrence of through holes due to corrosion of the steel plates over a long period of use, prevent water from entering the segment pieces, and prevent water from leaking into the tunnel interior, making it possible to maintain a higher quality tunnel lining over a long period of time.
In particular, according to the fourth aspect of the present invention, the inclusion of an acrylic resin in the liquid precoat paint (A) further improves the flexibility of the coating film, allowing the thick coating film to more effectively demonstrate its inherent flexibility against various impact loads expected during application, minimizing damage caused by these loads. This makes it possible to maintain a high-quality waterproofing film for a long period of time.
In particular, according to the fifth invention, the liquid precoat paint (A) is a one-component reactive curing type at room temperature, which improves the ease of painting work and makes it possible to form a coating film of uniform quality over a wide area, especially on the exterior surface, making it possible to provide a waterproof film of higher quality.
In particular, according to the sixth invention, the liquid precoat paint (A) is a water-based paint, which improves painting workability and makes it possible to form a coating film of uniform quality over a wide area, especially on the exterior surface, making it possible to provide a waterproof film of higher quality.
In particular, according to the seventh invention, the liquid precoat paint (A) contains at least one selected from a crosslinking agent, organic particles, inorganic particles, lubricant, and film-forming aid, which further improves the flexibility of the coating film, allowing the thick coating film to more effectively demonstrate its flexibility against various impact loads expected during application and minimize damage caused by these loads, thereby enabling the waterproofing film to be maintained at a higher quality for a longer period of time.
In particular, according to the eighth aspect of the present invention, by providing an epoxy resin coating underneath the thick resin coating, the adhesion between the thick coating and the surface of the segment pieces is improved, the flexibility of the thick coating is fully utilized against various impact loads that may be expected during construction, and damage caused by these loads can be minimized. This makes it possible to maintain a high-quality waterproofing film for a long period of time.
In particular, according to the twelfth aspect of the invention, by applying the liquid precoat paint (A) to the steel plates covering the outer surface after the steel shell is completed and before the concrete is poured, it is possible to utilize the storage period of the semi-finished product after the steel shell is completed and ensure sufficient time for the coating film to dry without significantly affecting the segment manufacturing process, thereby making it possible to form a high-quality waterproof film at low cost.
In particular, according to the thirteenth invention, by applying the liquid precoat paint (A) to the steel plate covering the outer surface after pouring concrete into the steel shell, the heat from the concrete hardening can be utilized to slowly warm the coating film from the inside, allowing it to dry under ideal conditions, further shortening the coating film drying time and enabling the formation of a high-quality waterproof film at lower cost.
In particular, according to the fourteenth invention, by pouring concrete with the outer surface of the steel shell facing upward, it becomes possible to apply the liquid precoat paint (A) downward in the same position, thereby making it possible to form a high-quality waterproof film more efficiently.
In particular, according to the fifteenth aspect of the present invention, by applying an epoxy resin paint before covering the segment pieces with a thick resin coating, the adhesion between the thick coating and the surface of the segment pieces is improved, the flexibility of the thick coating is fully exhibited against various impact loads expected during construction, and damage caused by these loads can be minimized. This makes it possible to form an even higher quality waterproof film.

FIG. 2 is a diagram illustrating one embodiment of the arrangement of an organic resin coating film in a segment piece of the present invention. 10A and 10B are diagrams illustrating another embodiment of the arrangement of an organic resin coating film in a segment piece of the present invention. FIG. 2 is a schematic diagram showing a segment wall constructed of segment pieces. FIG. 10 is an explanatory diagram illustrating the case where boat-shaped concrete pouring is applied in the segment piece manufacturing method of the present invention. FIG. 10 is an explanatory diagram of a case where concreting by concreting is applied in the manufacturing method of a segment piece of the present invention. FIG. 1 is a diagram showing an example of a test coated plate after a high-pressure scratch resistance test.

In this invention, segment pieces refer to components that are connected in multiple numbers to the wall surface excavated by a shield machine to form a shield tunnel, and any conventionally known segment piece can be used without restriction. Examples include reinforced concrete segments with reinforcing bars as the main steel material, and composite and/or steel segments with skin plates.

Next, an embodiment of the segment piece of the present invention will be described with reference to the drawings. Figure 1 is a schematic diagram showing an example of a segment piece of the present invention.

Figure 1 shows one embodiment of the arrangement of an organic resin coating film in a segment piece of the present invention. In this embodiment, the segment piece 1 coated with the organic resin coating film comprises an outer surface portion 2 that forms the outer surface of the shield tunnel facing the natural ground, an inner surface portion 4 that faces the outer surface portion and forms the inner surface facing the tunnel's interior, and a side surface portion 3 that connects the periphery of the outer surface portion and the inner surface portion. The surface of the outer surface portion 2 is coated with an organic resin coating film that acts as a waterproof membrane.

In Figure 1, the organic resin coating that serves as the waterproof membrane is formed only on the surface of the outer surface portion 2, but in the present invention, the arrangement of the organic resin coating is not limited, and for example, as shown in Figure 2, the organic resin coating may be applied to both the outer surface portion 2 and the inner surface portion 5. Furthermore, the organic resin coating may be applied to all surfaces, or, for example, only a portion of the surface of the side portion (not shown).

In the present invention, the thickness of the organic resin coating that serves as the waterproof film is 100 μm to 5,000 μm, preferably in the range of 500 to 3,000 μm, from the standpoints of high-pressure scratch resistance and waterproofing. In this specification, the film thickness is determined by theoretical calculation from the amount of coating.

In the present invention, the effects of the present invention can be particularly advantageously exhibited when at least the outer surface of the segment piece is coated with an organic resin coating film made from liquid precoat (A).

In the present invention, multiple segment pieces pre-coated with the organic resin coating are connected in the axial and circumferential directions to construct a highly durable segment wall, such as for a cylindrical tunnel (see Figure 3).

The precoat paint (A) used to form the organic resin coating that serves as the waterproofing film is described in detail below.

The liquid precoat paint (A) used in the present invention is a paint containing an organic resin component, a color pigment, an extender pigment, and a solvent.

<Organic resin component>
In the present invention, the organic resin component is not particularly limited, and either an organic solvent-diluted type or a water-diluted type can be used. Examples of resin types include acrylic resins, urethane resins, fluororesins, epoxy resins, alkyd resins, silicone resins, and combinations thereof.

The organic resin component is preferably contained in the nonvolatile content of the liquid precoat paint (A) in an amount of 20 to 75% by mass, and particularly 30 to 60% by mass.

In this specification, non-volatile content refers to the residue remaining after removing volatile components, and the residue may be solid or liquid at room temperature. For example, it refers to the residue remaining after treating a sample at 105°C for 3 hours and removing the volatile components.

In the present invention, from the viewpoints of high-pressure scratch resistance and adhesiveness, it is preferable that the resin component be a resin component whose main component is acrylic resin.

Examples of acrylic resins include resins obtained by copolymerizing a (meth)acryloyl compound with other polymerizable unsaturated monomers.

Examples of the (meth)acryloyl compound include:
Linear or branched alkyl (meth)acrylates such as methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, i-butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, and "isostearyl acrylate" (ISTA highly branched long-chain alkyl acrylate, manufactured by Osaka Organic Chemical Industry Co., Ltd.); alicyclic alkyl (meth)acrylates such as cyclohexyl (meth)acrylate, methylcyclohexyl (meth)acrylate, t-butylcyclohexyl (meth)acrylate, isobornyl (meth)acrylate, and adamantyl (meth)acrylate; aralkyl (meth)acrylates such as benzyl (meth)acrylate; 2-methoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, alkoxyalkyl (meth)acrylates such as hexafluoro-i-propyl (meth)acrylate, perfluorooctylmethyl (meth)acrylate, and perfluorooctylethyl (meth)acrylate; fluoroalkyl (meth)acrylates such as (2-acryloyloxyethyl) acid phosphate, (2-methacryloyloxyethyl) acid phosphate, (2-acryloyloxypropyl) acid phosphate, and (2-methacryloyloxyethyl) acid phosphate. (meth)acrylates containing a phosphate group, such as N,N-dialkylaminoalkyl (meth)acrylates such as N,N-diethylaminoethyl (meth)acrylate; (meth)acrylamide; (meth)acrylic acid; carbonyl group-containing (meth)acryloyl monomers, such as acetoacetoxyethyl (meth)acrylate and diacetone (meth)acrylamide; epoxy group-containing (meth)acryloyl monomers, such as glycidyl (meth)acrylate, β-methylglycidyl (meth)acrylate, 3,4-epoxycyclohexylmethyl (meth)acrylate, 3,4-epoxycyclohexylethyl (meth)acrylate and 3,4-epoxycyclohexylpropyl (meth)acrylate; isocyanato group-containing (meth)acryloyl monomers, such as isocyanatoethyl (meth)acrylate; alkoxy groups, such as γ-methacryloyloxypropyltrimethoxysilane and γ-methacryloyloxypropyltriethoxysilane. (meth)acryloyl monomers containing an alkoxysilyl group; allyl (meth)acrylate, ethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, 1,3-butylene glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, 1,4-butanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, polyvinyl compounds such as 1,1,1-trihydroxymethylethane di(meth)acrylate, 1,1,1-trihydroxymethylethane tri(meth)acrylate, and 1,1,1-trihydroxymethylpropane tri(meth)acrylate; dicyclopentenyloxyethyl (meth)acrylate, dicyclopentenyl (meth)acryloyl monomers containing an oxidative curing group, such as oxypropyl (meth)acrylate and dicyclopentenyl (meth)acrylate; 1,2,2,6,6-pentamethylpiperidyl (meth)acrylate, 2,2,6,6-tetramethylpiperidinyl (meth)acrylate; quaternary ammonium base-containing (meth)acrylates, such as 2-(methacryloyloxy)ethyltrimethylammonium chloride, 2-(methacryloyloxy)ethyltrimethylammonium bromide, methacryloylaminopropyltrimethylammonium chloride, methacryloylaminopropyltrimethylammonium bromide, tetrabutylammonium (meth)acrylate, tetramethylammonium (meth)acrylate, trimethylbenzylammonium (meth)acrylate, and 2-(methacryloyloxy)ethyltrimethylammonium dimethyl phosphate; (meth)acrylates having a polyoxyalkylene chain whose molecular terminal is an alkoxy group;
These can be used alone or in combination of two or more.

Other polymerizable unsaturated monomers include, for example, (meth)acrylonitrile; vinyl ester compounds such as vinyl acetate and vinyl propionate; vinyl aromatic compounds such as styrene and α-methylstyrene; carboxyl group-containing polymerizable unsaturated monomers such as maleic acid, crotonic acid, and β-carboxyethyl acrylate; carbonyl group-containing polymerizable unsaturated monomers such as (meth)acrolein, formylstyrene, vinyl alkyl ketones having 4 to 7 carbon atoms (e.g., vinyl methyl ketone, vinyl ethyl ketone, vinyl butyl ketone, etc.), and acetoacetoxy allyl esters; and epoxy group-containing polymerizable unsaturated monomers such as allyl glycidyl ether. unsaturated monomers; isocyanato group-containing polymerizable unsaturated monomers such as m-i-propenyl-α,α-dimethylbenzyl isocyanate; alkoxysilyl group-containing polymerizable unsaturated monomers such as vinyltrimethoxysilane and vinyltriethoxysilane; oxidatively curable group-containing polymerizable unsaturated monomers such as the reaction product of an epoxy group-containing polymerizable unsaturated monomer or a hydroxyl group-containing polymerizable unsaturated monomer with an unsaturated fatty acid; and fluorovinyl ethers such as fluoroalkyltrifluorovinyl ether and perfluoroalkyltrifluorovinyl ether. These may be used alone or in combination of two or more.

The weight-average molecular weight of the acrylic resin can be adjusted as appropriate, but can be within the range of 10,000 to 3,000,000, and particularly 50,000 to 1,000,000.

In this specification, the weight-average molecular weight is the value measured using a gel permeation chromatograph ("HLC8120GPC" manufactured by Tosoh Corporation) and converted to the weight-average molecular weight of polystyrene. Four columns were used: "TSKgel G-4000HxL," "TSKgel G-3000HxL," "TSKgel G-2500HxL," and "TSKgel G-2000HxL" (all manufactured by Tosoh Corporation). The measurement was performed under the following conditions: mobile phase: tetrahydrofuran, measurement temperature: 40°C, flow rate: 1 cc/min, detector: RI.

From the viewpoints of ease of application and the waterproofing properties of the organic resin coating film, it is appropriate for the liquid precoat paint (A) to be a one-component reactive curing type at room temperature. For this reason, it is preferable for the acrylic resin to contain a carbonyl group-containing polymerizable unsaturated monomer as a copolymerization component.

Examples of carbonyl group-containing polymerizable unsaturated monomers include acetoacetoxyethyl (meth)acrylate, diacetone (meth)acrylamide, (meth)acrolein, formylstyrene, vinyl methyl ketone, vinyl ethyl ketone, vinyl butyl ketone, acetoacetoxyallyl ester, and combinations thereof.

The copolymerization ratio of the carbonyl group-containing polymerizable unsaturated monomer is preferably within the range of 1 to 20% by mass, and more preferably within the range of 3 to 15% by mass, based on the total polymerizable unsaturated monomers used in the production of the acrylic resin.

Furthermore, from the viewpoint of high-pressure scratch resistance, it is preferable that the acrylic resin contains an acrylate containing a linear or branched alkyl group having 4 or more carbon atoms as a copolymerization component.

Examples of the acrylate containing a linear or branched alkyl group having 4 or more carbon atoms include n-butyl acrylate, i-butyl acrylate, t-butyl acrylate, n-pentyl acrylate, n-hexyl acrylate, heptyl acrylate, octyl acrylate, 2-ethylhexyl acrylate, and combinations thereof.

The copolymerization ratio of the acrylate containing a linear or branched alkyl group having 4 or more carbon atoms is preferably 50% by mass or more, and more preferably 65 to 85% by mass, based on the total polymerizable unsaturated monomers used in the production of the acrylic resin.

Furthermore, it is preferable that the organic resin component contains, as part of its components, an acrylic resin in which the copolymerization ratio of an acrylate containing a linear or branched alkyl group having 4 or more carbon atoms is less than 50% by mass.

Examples of the polymerizable unsaturated monomer and acrylate containing a linear or branched alkyl group having 4 or more carbon atoms used in the acrylic resin include the compounds exemplified above.

In the present invention, from the viewpoint of high-pressure scratch resistance, it is preferable to use in combination an acrylic resin (a1) in which the copolymerization ratio of acrylate containing a linear or branched alkyl group having 4 or more carbon atoms is 50% by mass or more based on all polymerizable unsaturated monomers used in the production of the acrylic resin, and an acrylic resin (a2) in which the copolymerization ratio of acrylate containing a linear or branched alkyl group having 4 or more carbon atoms is less than 50% by mass based on all polymerizable unsaturated monomers used in the production of the acrylic resin. A suitable combination ratio is within a mass ratio range of 5/95 to 95/5.

When the acrylic resin used in the present invention is aqueous, it may be either an emulsion type or a water-soluble type, but an emulsion type is preferred. Emulsion-type acrylic resins can be produced, for example, by emulsion polymerization of the polymerizable unsaturated monomer components in the presence of water and a dispersion stabilizer, in one stage or multiple stages.

<Coloring pigments>
The color pigment contained in the liquid precoat paint (A) may be an inorganic or organic pigment, used alone or in combination. Examples of inorganic pigments include titanium dioxide, yellow iron oxide, red iron oxide, carbon black, and combinations thereof. Examples of organic pigments include azo lake pigments, insoluble azo pigments, condensed azo pigments, phthalocyanine pigments, indigo pigments, perinone pigments, perylene pigments, phthalone pigments, dioxazine pigments, quinacridone pigments, isoindolinone pigments, metal complex pigments, and combinations thereof.

<Extender pigment>
Examples of the extender pigment include calcium carbonate, clay, silica, barium sulfate, talc, white carbon, diatomaceous earth, magnesium aluminum carbonate flakes, mica flakes, and combinations thereof.

In the present invention, from the standpoint of high-pressure scratch resistance and waterproofing, the color pigments and extender pigments are preferably included so that the total pigment volume concentration is 10-60%, and more preferably 15-55%. In this specification, pigment volume concentration refers to the volume ratio of the pigment to the total solids of all resins and all pigments in the paint. In this specification, the specific gravity of the pigment, which is the basis for calculating the pigment volume, is taken from "Encyclopedia of Pigments" (editor-in-chief: Ito Seijiro), and the specific gravity of the resin solids is assumed to be approximately 1.

<Solvent>
The liquid precoat paint (A) contains a solvent, which makes it possible to provide waterproofing by the organic resin coating film even if the surface of the component to be coated has a complex shape or an intricate structure.

The solvent contained in the liquid precoat paint (A) may be either an organic compound or water, as long as it is a volatile substance that does not remain in the film after application. However, due to the favorable application environment, it is preferable that the main component be water and that the liquid precoat paint (A) be an aqueous paint. "Aqueous" is a term that contrasts with organic solvent-based, and generally means that the solvent is water only or contains water as the main component (aqueous solvent), while "organic solvent-based" means that the solvent does not substantially contain water, or that all or most of the solvent is an organic solvent.

<Liquid precoat paint (A)>
From the viewpoint of waterproofing and high-pressure scratch resistance, the liquid precoat paint (A) preferably further contains at least one selected from the group consisting of a crosslinking agent, organic particles, inorganic particles, a lubricant, and a film-forming aid.

Of these, known crosslinking agents can be used, such as amino resins, polyisocyanate compounds, polyhydrazide compounds, polysemicarbazide compounds, carbodiimide group-containing compounds, oxazoline group-containing compounds, epoxy compounds, and polycarboxylic acids. Polyhydrazide compounds are particularly preferred.

Specific examples of polyhydrazide compounds include dihydrazides of saturated aliphatic carboxylic acids having 2 to 18 carbon atoms, such as oxalic dihydrazide, malonic dihydrazide, succinic dihydrazide, glutaric dihydrazide, adipic dihydrazide, and sebacic dihydrazide; dihydrazides of monoolefinically unsaturated dicarboxylic acids, such as maleic dihydrazide, fumaric dihydrazide, and itaconic dihydrazide; dihydrazides of phthalic acid, terephthalic acid, or isophthalic acid; and pyrrolidone. Examples include citric acid dihydrazide, trihydrazide, or tetrahydrazide; nitrilotriacetic acid trihydrazide, citric acid trihydrazide, 1,2,4-benzenetrihydrazide; ethylenediaminetetraacetic acid tetrahydrazide, 1,4,5,8-naphthoic acid tetrahydrazide; polyhydrazides obtained by reacting a low polymer having a carboxylic acid lower alkyl ester group with hydrazine or hydrazine hydrate (hydrazine hydrade), and combinations thereof.

From the perspective of high-pressure scratch resistance, the content of the crosslinking agent is preferably within the range of 0.01 to 5.0 parts by mass, and particularly 0.02 to 0.8 parts by mass, based on 100 parts by mass of the nonvolatile content of the liquid precoat paint (A).

Examples of the organic particles include particles of polyacrylate resin, polymethacrylate resin, polyolefin resin, polystyrene resin, polyamide resin, polyamino acid resin, polyester resin, polyurethane resin, polyvinyl chloride resin, cellulose resin, melamine resin, urea resin, epoxy resin, fluororesin, and copolymers thereof. The organic particles may be commercially available, such as the Ganz Pearl series and Staphyloid series manufactured by Aica Kogyo Co., Ltd., the Chemi Pearl series manufactured by Mitsui Chemical Co., Ltd., the Art Pearl series manufactured by Negami Chemical Industrial Co., Ltd., the Eposter series manufactured by Nippon Shokubai Co., Ltd., the Tuftic series manufactured by Toyobo Co., Ltd., and the Techpolymer series manufactured by Sekisui Chemical Co., Ltd.

Examples of inorganic particles include silica particles. Examples of silica particles that can be used include powdered silica and colloidal silica. Commercially available silica particles may also be used. Examples of commercially available silica particles include the Aerosil series manufactured by Nippon Aerosil Co., Ltd., the Carplex series manufactured by Evonik Industries, the Shieldex series manufactured by Asahi Glass Co., Ltd., the Sylysia series manufactured by Fuji Silysia Corporation, the Snowtex series manufactured by Nissan Chemical Industries, and the Adelite series manufactured by ADEKA Corporation.

The above organic or inorganic particles can be used alone or in combination. The content is preferably within the range of 0.5 to 10% by mass, and particularly 1.0 to 8.0% by mass, of the nonvolatile content of the liquid precoat paint (A).

The liquid precoat paint (A) preferably contains a lubricant to improve resistance to high-pressure scratches. Examples of lubricants include wax, silicone compounds, and perfluoroalkyl compounds.

Examples of waxes include paraffin wax, polyolefin wax, ester wax, which is a condensate of a fatty acid with a monohydric alcohol or a polyhydric alcohol, and carnauba wax. The wax is preferably added as wax particles contained in an aqueous emulsion in which the wax is dispersed in water. Commercially available waxes may be used, including, for example, the AQUACER series, CERACOL series, and CERAFLOUR series manufactured by BYK, and the CHEMIPEARL series manufactured by Mitsui Chemicals, Inc.

Examples of silicone compounds include polysiloxane surfactants and polyether-modified polysiloxanes.

Perfluoroalkyl compounds include perfluoroalkyl sulfonates, perfluoroalkyl carboxylates, perfluoroalkyl phosphates, perfluoroalkyl ethylene oxide adducts, perfluoroalkyl betaines, and perfluoroalkyl amine oxide compounds.

The above lubricants can be used alone or in combination. The content of the lubricants is preferably within the range of 0.1 to 10% by mass, and particularly 0.5 to 5.0% by mass, of the nonvolatile content of the liquid precoat paint (A).

Examples of film-forming aids include glycol ethers such as ethylene glycol mono-i-propyl ether, ethylene glycol dibutyl ether, diethylene glycol mono-n-butyl ether, diethylene glycol mono-i-butyl ether, diethylene glycol mono-n-propyl ether, diethylene glycol mono-i-propyl ether, dipropylene glycol mono-n-butyl ether, dipropylene glycol mono-i-butyl ether, dipropylene glycol mono-n-propyl ether, dipropylene glycol mono-i-propyl ether, diethylene glycol dibutyl ether, dipropylene glycol monobutyl ether, and tripropylene glycol monobutyl ether; and ester compounds such as 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate, 2,2,4-trimethyl-1,3-pentanediol diisobutyrate, 2,2,4-trimethyl-1,3-pentanediol mono-2-ethylhexanoate, and 2,2,4-trimethyl-1,3-pentanediol di-2-ethylhexanoate.

The above film-forming aids can be used alone or in combination. From the viewpoint of alkali resistance, the content is preferably 5.0% by mass or less, and particularly preferably in the range of 0.1 to 2.5% by mass, of the nonvolatile content of the liquid precoat paint (A).

In addition to the components described above, the liquid precoat paint (A) may contain paint additives such as plasticizers, thickeners, antifoaming agents, dispersants, flame retardants, and neutralizing agents, as needed.

<Method of manufacturing segment pieces>
The segment pieces of the present invention are produced by applying the liquid precoat paint (A) to at least a portion of the surface of the segment pieces before the segments are joined.

The organic resin coating film formed by the precoat paint (A) has excellent pressure scratch resistance, so it is particularly preferable to apply it to at least the outer surface (basis ground side) of the segment piece. By applying it before connecting the segments, the effects of the present invention can be maximized.

Application methods include, for example, roller, air spray, airless spray, lysine gun, all-purpose gun, and brush, and multiple coats can be applied to achieve the desired dry film thickness.

The formed organic resin coating can be dried at room temperature, but heat drying may also be used if necessary.

In the present invention, an epoxy resin coating containing an epoxy resin may be provided below the organic resin coating. The epoxy resin coating used to form the epoxy resin coating below the organic resin coating can be one whose main component is an epoxy resin and which is cured by mixing in a curing agent. Examples of epoxy resins include bisphenol-type epoxy resins such as bisphenol A epoxy resin and bisphenol F epoxy resin, and novolac epoxy resins. Examples of curing agents include polyamines such as ethylenediamine and diethylenetriamine, amine adducts in which epoxy resins are added to the above polyamines, and various polyamines. The dry film thickness of the epoxy resin coating is preferably in the range of 10 to 200 μm, and more preferably in the range of 30 to 150 μm.

The present invention also provides a method for manufacturing a segment piece, in which the segment piece is a so-called composite segment piece in which the steel shell and concrete are integrated, including pouring concrete into the steel shell and then painting the liquid precoat paint (A) on the outer surface of the steel shell.

In the present invention, there are no particular restrictions on the method of pouring concrete, and any known method can be used.

Figure 4 is an explanatory diagram of the application of boat-shaped concrete pouring to the present invention. As shown in Figure 4(a), when the concrete 7 pouring process is carried out with the outer surface of the steel shell of the segment piece 8 facing downward, the concrete is cured in a boat-like convex shape, as shown in Figure 4(b). Therefore, when applying liquid precoat paint (A) to the outer surface of the steel shell, the integrated steel shell and concrete after demolding is usually inverted so that the outer surface of the steel shell faces upward and convex upward, as shown in Figure 4(c), and then painted using, for example, a paint roller 9 to cover it with an organic resin coating 10.

Figure 5 is an explanatory diagram of the application of face-down concrete pouring to the present invention. As shown in Figure 5(a), the outer surface of the steel shell of the segment piece 8 is provided with a pouring port 11 for filling with concrete 7. Concrete 7 is poured into this pouring port 11 with the outer surface of the steel shell facing up, like an upside-down bowl. When applying liquid precoat paint (A) to the outer surface of the steel shell, this is usually done after closing the pouring port 11 with a lid 12, as shown in Figure 5(b). This manufacturing method does not require inverting the heavy integrated steel shell and concrete assembly, and it is possible to apply the liquid precoat paint (A) while the concrete is curing, thereby covering it with an organic resin coating 10 (see Figure 5(c)).

The segment piece manufacturing method of the present invention can include a step of applying an epoxy resin paint containing an epoxy resin before applying the liquid precoat paint (A). This allows an epoxy resin paint containing an epoxy resin to be formed under the organic resin paint. Epoxy resin paints have been described above. The epoxy resin paint can be applied using, for example, a roller, air spray, airless spray, lysine gun, universal gun, or brush, and multiple coats can be applied to achieve the desired dry film thickness. The formed epoxy resin paint can be dried at room temperature, but heat drying may also be used if necessary.

The present invention will be further explained below with reference to examples. Hereinafter, "parts" and "%" mean "parts by mass" and "% by mass," respectively.

Manufacturing example (manufacturing liquid precoat paint)
Liquid precoat paints (X-1) to (X-18) were prepared according to the formulations shown in Tables 1 and 2 below.

Examples 1 to 23 and Comparative Examples 1 and 2
A black steel plate measuring 70 mm wide x 150 mm long x 2.3 mm thick was prepared as a support for the test, assuming the skin plate used on the outer surface of the steel shell of a composite segment.

The liquid precoat paints (X-1) to (X-18) obtained in the above production examples were subjected to the following evaluation tests. The evaluation results are shown in Tables 1 and 2.

(Notes 1) to (Notes 11) in the table are as follows:
(Note 1) 50% acrylic resin emulsion (A-1):
Emulsion polymer of styrene/n-butyl acrylate/2-ethylhexyl acrylate/methacrylic acid/diacetone acrylamide=10/1/80/3/6, weight average molecular weight 300,000
(Note 2) 50% acrylic resin emulsion (A-2):
Emulsion polymer of styrene/n-butyl acrylate/2-ethylhexyl acrylate/methyl methacrylate/hydroxyethyl acrylate/acrylic acid/diacetone acrylamide/1,6-hexamethylene diacrylate = 15/24/15/41/2/0.3/2.3/0.4 (Note 3) Color pigment: titanium oxide, specific gravity 4.1
(Note 4) Extender pigment: calcium carbonate, specific gravity 2.7
(Note 5) 33% colloidal silica: "Snowtex O-33", product name, manufactured by Nissan Chemical Industries, Ltd. (Note 6) 80% resin particles: "Ganzpearl GM-1702H", product name, manufactured by Aica Kogyo Co., Ltd. (Note 7) 50% wax emulsion: "AQUACER 497", product name, manufactured by BYK Corporation (Note 8) Polyether polysiloxane: "TEGOGlide 410", product name, manufactured by Evonic Corporation (Note 9) Coal-forming agent: 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate (Note 10) Urethane-based waterproof coating material:
Main component: Tolylene diisocyanate and polypropylene glycol-based isocyanate-terminated urethane prepolymer/xylene = 24/1. Hardener: Polypropylene glycol/plasticizer/calcium carbonate/titanium oxide/carbon black/xylene = 10/7/46/0.3/0.1/6. Two-component waterproofing material. Main component/hardener mass ratio is 1:3.
(Note 11) Epoxy/amine-based anticorrosive paint:
Base: bisphenol A epoxy resin with an epoxy equivalent of 190 / bisphenol F epoxy resin with an epoxy equivalent of 190 / titanium oxide / talc / xylene = 60 / 40 / 5 / 5 / 2. Curing agent: aromatic polyamidoamine with an amine value of 360 / titanium oxide / xylene = 20 / 25 / 2. The mass ratio of base to curing agent is 2:1.

<Evaluation test>
(*) High-pressure scratch resistance:
A black steel plate substrate was coated with a paint ("ESCO NB" brand name, manufactured by Kansai Paint Co., Ltd., a two-component ketimine-cured modified epoxy resin rust preventative paint) containing a 9/1 mixture of base and curing agent to a dry film thickness of 60 μm. After drying at 23°C for 8 hours, each liquid precoat paint listed in Tables 1 and 2 was applied to the coating thickness listed in the table and dried at 23°C for 7 days to prepare test coated panels. At room temperature of 23°C, a high-pressure scratch resistance tester (manufactured by Kansai Paint Co., Ltd.) was used to press the edge of a contact plate (SUS304H spring steel plate) against the coated surface of each test coated panel, holding the edge at a 45° angle with a load of 100 kg, while moving the test coated panel 100 mm at a speed of 10 mm/sec. The coating condition was observed and evaluated according to the following criteria. Figure 6 shows an example of a test coated panel after the high-pressure scratch resistance test. In this example, scratches such as dents, scuffs, and scales were observed.
⊚: No damage such as dents, gouges, or scales was observed.
Good: Some damage such as dents, gouges, and scales is observed, but the metal base is completely undetectable.
△: Damage such as dents, gouges, and scales is observed, and the metal base is also visible.
×: The coating surface peels off entirely.
In the case of a rating of ⊚, the high-pressure scratch resistance is particularly excellent, and in the case of a rating of ◯, the scratches have not reached the metal base, so it can be said that it is practically usable. On the other hand, in the case of a rating of △×, the scratches have reached the metal base, so it is judged that it is not suitable for practical use.

(*)Drying property:
Test coated plates were prepared in the same manner as in the high-pressure scratch resistance test, and the surface of the coating film was pressed with tissue paper and then peeled off, after which the remaining film was evaluated according to the following criteria.
◎: The coating surface is not sticky at all and tissue paper does not stick to it.
○: The coating surface is slightly sticky, but the tissue paper peels off without leaving any residue.
△: The coating surface is sticky and tissue paper remains slightly.
×: The coating film adhered to the tissue paper.
In the case of a rating of ⊚, the drying property is particularly excellent, and in the case of a rating of ◯, no tissue paper is left behind, so it can be said to be practical. On the other hand, in the case of a rating of △×, there is stickiness or adhesion to the tissue paper, making it difficult to transport the waterproofed components, and it is judged to be unsuitable for practical use.

(*) Adhesiveness:
Test coated plates were prepared using the same method as in the high-pressure scratch resistance test described above, and adhesion was examined using a method (pull-off test method) in accordance with JIS K5600-5-7 (2014). The measurement position on each test plate was lightly polished with sandpaper to clean it, and then attached to a dolly (test cylinder) with a diameter of 20 mm using adhesive. The coating film around the dolly was cut with a cutter, and the dolly was peeled off with a tester, and the strength (MPa) at that time was observed.
◎: 0.9 MPa or more,
○: 0.6 MPa or more and less than 0.9 MPa
△: 0.3 MPa or more and less than 0.6 MPa
×: Less than 0.3 MPa.
In the case of a rating of ◎ ◯, the adhesive strength standard of the Road Bridge Deck Waterproofing Handbook was met, and it was judged that the adhesive strength was sufficient as a waterproof coating film. In the case of a rating of △ or ×, the standard was not met, and it was therefore judged as a failure here.

(*) Waterproof:
Each liquid precoat paint (A) shown in Tables 1 and 2 was applied to a polypropylene plate to a film thickness shown in the table, and dried at 23° C. for 7 days to obtain a free film.
In the present invention, a test was conducted in accordance with BS EN 14150 to reproduce groundwater pressure and confirm the waterproofness of a coating film. Specifically, a free film was sandwiched between a cell attached to a waterproof tester (manufactured by Kansai Paint Co., Ltd.), and the tester was completely filled with water. After that, high pressure (0.15 MPa) was applied to one side of the free film and low pressure (0.05 MPa) was applied to the other side to generate a pressure difference, and the amount of water passing through the film was measured and evaluated according to the following criteria.
◎: Less than 0.05 [L/m ² /day],
〇: 0.05 [L/m ² /day] to 0.1 [L/ ^{m 2} /day],
△: More than 0.1 [L/m ² /day] to 0.5 [L/m ² /day];
×: More than 0.5 [L/m ² /day].
In the cases where the ratings are ◎ and ◯, it can be said that the BTS Class 3 standard is met and water permeation is well suppressed even under high pressure. In the cases where the ratings are △ and ×, it is determined that the waterproofing is insufficient under groundwater pressure and that the material is not suitable for practical use.

(*) Alkali resistance:
Each liquid precoat paint (A) shown in Tables 1 and 2 was applied to a polypropylene plate to a film thickness shown in Tables 1 and 2, and then dried at 23°C for 7 days to obtain a free film. This free film was immersed in saturated lime water at 50°C for 56 days and subjected to the waterproofing test described above. The evaluation criteria were the same as those for the waterproofing test.
In the cases where the ratings are ◎ and ◯, it can be said that the BTS Class 3 standard is met, and water permeation is effectively suppressed even under high pressure and in an alkaline environment such as concrete. In the cases where the ratings are △ and ×, it is determined that the waterproofing is insufficient under groundwater pressure and in an alkaline environment, and that the material is not suitable for practical use.

The above provides a detailed description of embodiments and examples of the present invention, but the present invention is not limited to the above-described embodiments, and various modifications based on the technical concept of the present invention are possible.

Explanation of symbols

1: Segment piece coated with organic resin coating film 2: Organic resin coating film (outer surface of segment piece)
3: Side surface of segment piece 4: Inner surface of segment piece 5: Organic resin coating film (inner surface of segment piece)
6: Segment wall body 7: Concrete 8: Segment piece 9: Paint roller 10: Organic resin coating film 11: Pouring hole 12: Lid material

Claims (16)

A segment piece for forming a shield tunnel by connecting a plurality of segments in the circumferential and axial directions,
the segment piece has an outer surface portion that forms the outer surface of the shield tunnel on the natural ground side, an inner surface portion that faces the outer surface portion and forms the inner surface on the tunnel space side, and a side surface portion that connects the periphery of the outer surface portion and the inner surface portion,
At least a portion of the surface of the segment pieces before connection is coated with an organic resin coating film having a film thickness of 100 μm to 5000 μm, which is formed from a liquid precoat paint (A) containing an organic resin component , a color pigment, an extender pigment, a lubricant , and a solvent ,
The segment piece , wherein the lubricant comprises wax particles dispersed in water as a water-based emulsion . The segment piece according to claim 1, wherein at least the outer surface of the segment piece is coated with the organic resin coating. The segment piece according to claim 1 or 2, wherein the segment piece comprises a steel shell having steel plates covering at least the outer surface thereof and the steel shell is filled with concrete, and at least a portion of the surface of the steel shell is painted with a liquid precoat paint (A). The segment piece according to any one of claims 1 to 3, wherein the content of the lubricant is 0.1 to 10 mass% in terms of nonvolatile content in the nonvolatile content of the liquid precoat paint (A). The segment piece according to any one of claims 1 to 4 , wherein the organic resin component contained in the liquid precoat paint (A) includes an acrylic resin. The segment piece according to any one of claims 1 to 5 , wherein the liquid precoat paint (A) is a one-component reactive curing type at room temperature. The segment piece according to any one of claims 1 to 6 , wherein the liquid precoat paint (A) is a water-based paint. The segment piece according to any one of claims 1 to 7 , wherein the liquid precoat paint (A) further contains at least one selected from the group consisting of a crosslinking agent, organic particles, inorganic particles, and a film-forming aid. The segment piece according to any one of claims 1 to 8 , wherein an epoxy resin coating film is provided under the organic resin coating film. A segment wall body formed by connecting a plurality of segment pieces according to any one of claims 1 to 9 . A manufacturing method of segment pieces for forming a shield tunnel by connecting a plurality of segment pieces in the circumferential direction and the axial direction,
the segment piece has an outer surface portion that forms the outer surface of the shield tunnel on the natural ground side, an inner surface portion that faces the outer surface portion and forms the inner surface on the tunnel space side, and a side surface portion that connects the periphery of the outer surface portion and the inner surface portion,
a liquid precoat paint (A) containing an organic resin component, a color pigment, an extender pigment , a lubricant , and a solvent is applied to at least a portion of the surface of the segment piece before the segment is connected, so that the dry film thickness is 100 μm to 5000 μm ;
The method for producing segment pieces , wherein the lubricant comprises wax particles dispersed in water as a water-based emulsion . A manufacturing method of segment pieces for forming a shield tunnel by connecting a plurality of segment pieces in the circumferential direction and the axial direction,
the segment piece has an outer surface portion that forms the outer surface of the shield tunnel on the natural ground side, an inner surface portion that faces the outer surface portion and forms the inner surface on the tunnel space side, and a side surface portion that connects the periphery of the outer surface portion and the inner surface portion,
a liquid precoat paint (A) containing an organic resin component, a coloring pigment, an extender pigment , a lubricant , and a solvent is applied to at least the outer surface of the segment piece before the segment is connected, so that the dry film thickness is 100 μm to 5000 μm ;
The method for producing segment pieces , wherein the lubricant comprises wax particles dispersed in water as a water-based emulsion . the segment piece is formed by filling a steel shell with concrete and having a steel plate covering at least an outer surface portion of the steel shell,
13. The method for manufacturing a segment piece according to claim 12, further comprising painting a liquid precoat paint (A) on at least a part of the surface of an outer surface of the steel shell after the steel shell is completed and before concrete is poured into the steel shell . the segment piece is formed by filling a steel shell with concrete and having a steel plate covering at least an outer surface portion of the steel shell,
13. The method for manufacturing a segment piece according to claim 12 , comprising painting a liquid precoat paint (A) on at least a part of the surface of the outer surface of the steel shell after pouring concrete into the steel shell. 15. The method for manufacturing a segment piece according to claim 14 , wherein an outer surface portion of the steel shell is provided with a pouring port for filling with concrete, and concrete is poured into the pouring port with the outer surface portion of the steel shell facing upward. The method for manufacturing a segment piece according to any one of claims 11 to 15 , further comprising a step of applying an epoxy resin paint before applying the liquid precoat paint (A).