JP3264371B2 - Coating for friction reducing agent for latent box method or propulsion method and latent box method or propulsion method using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a method of burying various tanks and water tanks in the ground, and to bury (horizontal and vertical) various fume pipes, steel pipes and steel pipe piles in the ground. Tanks, water storage tanks,
Pre-coating on fume pipes, steel pipes, steel pipe piles (base material), etc., reduces the friction between the base material surface and soil when buried underground, making it easier to bury (speeding up burial, The present invention relates to a paint for a friction reducing agent for lowering the pushing force at the time of embedding, etc.), and a latent box method and a propulsion method using the above-mentioned paint for a friction reducing agent.

[0002]

2. Description of the Related Art Conventionally, various base materials (tanks, water storage tanks,
In the submersion method and the propulsion method for embedding fume pipes, steel pipes, steel pipe piles, etc. in the ground, various problems have occurred due to friction between various base materials and soil.

For example, in a submersion method in which tanks are sunk into the ground by excavating earth and sand on the lower surface of the tanks, since no earth retaining wall is used, the ground on the side wall of the tank during the settlement of the tank is not used. There was a problem that the earth pressure was applied to the side of the tank, making it extremely difficult to sink.

On the other hand, in the propulsion method, if the friction between the base material (such as steel pipe) and the soil is large, it is difficult to push the base material. Therefore, a lubricant (a bentonite / water mixture) is usually provided around the base material. And the like), but such a lubricant has problems such as lowering the strength of the surrounding ground and necessitating post-processing of the lubricant.

To solve these problems, various solutions have been studied so far.

[0006] For example, in Japanese Patent Application Laid-Open No. Hei 4-23514, a film having a small amount of water is provided by sandwiching a film (adhesive to the substructure) / lubricant (oil or the like) / film (soil side) between a substructure / soil. Above all, it has been proposed that the friction between the substructure and the soil can be reduced. In this case, if the substructure is first installed by the submersion method or the propulsion method, it will peel off during the installation. There was a fatal flaw.

In Japanese Patent Publication No. 6-39784, the friction between the substructure and the soil is reduced by pre-coating a substructure such as a pile with a water-in-oil type water-swellable polymer particle emulsion or an aqueous dispersion thereof. It has been proposed that this can be done, but in this case too,
In the case of casting by a submersion method or a propulsion method, there was a fatal defect that the material was peeled off during the casting.

[0008] As described above, there has been no good friction-reducing agent having a sustained release property which can be used for the latent box method or the propulsion method.

[0009]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and an object of the present invention is to easily construct a base material buried in the ground, The entire friction-reducing agent coating film does not peel off from the substrate during casting by the latent box method, propulsion method, etc. (The swelling friction-reducing agent layer on a part of the surface is peeled off at the time of casting as a friction-reducing agent.) ), The surface of the coating film swells due to moisture given in advance or absorbed from the ground after embedding in the ground or during the latent box method or the propulsion method, and the swelling (friction reducing agent) layer is gradually released between the base material and the soil. It can be supplied, and its sustained release property is to provide a coating for a friction reducing agent that can respond to soil of any property by adjusting the hydrophilicity of the binder resin, the thickness of the coating film, and the like. .

[0010] Furthermore, by using the above-mentioned paint for a friction reducing agent, the frictional force between the substrate and the soil can be reduced while minimizing the influence on the surrounding ground, and the construction speed and
The purpose is to provide a submersion method and a propulsion method that can significantly improve efficiency.

[0011]

In order to solve the above-mentioned conventional problems, the inventor of the present invention adheres well to a substrate used in a latent box method or a propulsion method, and does not peel off all at once. During the period (during construction or embedding in the latent box method or the propulsion method), a friction reducing agent paint capable of supplying the friction reducing agent layer in a sustained manner and maintaining the friction reducing effect was studied diligently.

As a result, it is necessary to previously apply a coating material for a friction reducing agent containing a water-absorbing resin (a), a hydrophilic binder resin (b) and a solvent (c) as essential components to the substrate. As a result, the inventors have found that the above problems can be solved, and have completed the present invention.

First, the paint for a friction reducing agent of the present invention will be described below. Water absorbent resin (a) used in the present invention
Is swollen by absorbing water, and the absorption capacity of ion-exchanged water with respect to its own weight is 3 times or more (25 ° C., 1
The time is not particularly limited. However, a synthetic water-absorbent resin obtained by crosslinking a water-soluble hydrophilic compound (monomer and / or polymer) with a crosslinking agent, as exemplified below, has a higher swelling ratio and water swelling capacity than natural water-swellable substances (gelatin, agar, etc.). These are more preferable than natural water-swellable substances (gelatin, agar, etc.) because they have a good balance of the content of water, water absorption rate, strength and the like, and are easily adjusted.

As the water-absorbing resin (a) as described above,
Specifically, for example, cross-linked poly (meth) acrylic acid,
Cross-linked poly (meth) acrylate, cross-linked poly (meth) acrylate having a sulfonic group, cross-linked poly (meth) acrylate having a polyoxyalkylene group, cross-linked poly (meth) acrylamide, Meta)
Crosslinked copolymer of acrylate and (meth) acrylamide, hydroxyalkyl (meth) acrylate and (meth)
Cross-linked copolymer with acrylate, cross-linked polydioxolane, cross-linked polyethylene oxide, cross-linked polyvinyl pyrrolidone, cross-linked sulfonated polystyrene, cross-linked polyvinyl pyridine, saponified starch-poly (meth) acrylonitrile graft copolymer, starch- Poly (meth) acrylic acid (salt) graft crosslinked copolymer, reaction product of polyvinyl alcohol and maleic anhydride (salt), crosslinked polyvinyl alcohol sulfonate, polyvinyl alcohol-acrylic acid graft copolymer, polyisobutylene maleic Acid (salt) cross-linked polymers and the like. One of these water-absorbing resins may be used alone, or two or more thereof may be used in combination.

In the present invention, it is preferable to use a salt-resistant water-absorbing resin as the water-absorbing resin (a). The reason why the salt-resistant water-absorbent resin is preferable is that the salt-resistant water-absorbent resin has a relatively high water absorption ratio of hard water containing a polyvalent metal, and when used for a friction-reducing agent paint, is largely affected by the water quality in the soil. This is because a friction reducing effect can be exhibited.

The salt-resistant water-absorbing resin of the present invention is not particularly limited as long as it has a water absorption capacity of 10 times or more in artificial seawater (25 ° C., 24 hours). Among the resins (a), those having a nonionic group and / or a sulfonic acid (salt) group are more preferable, and those having an amide group or a hydroxyalkyl group are still more preferable. As the salt-resistant water-absorbing resin as described above,
For example, a cross-linked copolymer of (meth) acrylate and (meth) acrylamide, a cross-linked copolymer of hydroxyalkyl (meth) acrylate and (meth) acrylate, and the like can be given. Further, those having a polyoxyalkylene group are particularly preferred. Examples of such a water-absorbent resin (a) include a crosslinked copolymer of a (meth) acrylate having a methoxypolyoxyalkylene group and a (meth) acrylate.

The use of these salt-resistant water-absorbent resins allows the properties of water in the soil (soft water, hard water, etc.)
Swells to a certain magnification regardless of the above, and can more reliably exhibit the friction reducing function.

Furthermore, the water-absorbent resin (a) according to the present invention
The method for producing is not particularly limited, and examples thereof include a method of polymerizing a monomer component containing a water-soluble ethylenically unsaturated monomer and, if necessary, a crosslinking agent. The water-absorbent resin (a) obtained by (co) polymerizing an ethylenically unsaturated monomer is more excellent in water absorbency with respect to water, and
Generally inexpensive. In addition, the above-mentioned crosslinking agent is not particularly limited.

The above ethylenically unsaturated monomers include:
Specifically, for example, acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, citraconic acid, vinylsulfonic acid, (meth) allylsulfonic acid,
2- (meth) acrylamide-2-methylpropanesulfonic acid, 2- (meth) acryloylethanesulfonic acid,
2- (meth) acryloylpropanesulfonic acid, and alkali metal salts and ammonium salts of these monomers;
N, N-dimethylaminoethyl (meth) acrylate,
And quaternary compounds thereof; (meth) acrylamide, N,
(Meth) acrylamides such as N-dimethyl (meth) acrylamide, 2-hydroxyethyl (meth) acrylamide, diacetone (meth) acrylamide, N-isopropyl (meth) acrylamide, (meth) acryloylmorpholine, and monomers thereof A hydroxyalkyl (meth) acrylate such as 2-hydroxyethyl (meth) acrylate and 2-hydroxypropyl (meth) acrylate; polyethylene glycol mono (meth) acrylate, polypropylene glycol mono (meth) acrylate, methoxypolyethylene glycol mono ( Polyalkylene glycol mono (meth) acrylates such as meth) acrylate and methoxy polypropylene glycol mono (meth) acrylate; N-vinyl-
N-vinyl monomers such as 2-pyrrolidone and N-vinylsuccinimide; N-vinylformamide, N-vinyl-N
-Methylformamide, N-vinylacetamide, N-
N-vinylamide monomers such as vinyl-N-methylacetamide; vinyl methyl ether; and the like, but are not particularly limited. These ethylenically unsaturated monomers may be used alone or in combination of two or more.

Among the ethylenically unsaturated monomers exemplified above, those composed of an ethylenically unsaturated monomer having a nonionic group and / or a sulfonic acid (salt) group are more preferable because of their high salt resistance. Examples of the monomer include 2
-(Meth) acrylamide-2-methylpropanesulfonic acid, 2- (meth) acryloylethanesulfonic acid, 2
-(Meth) acryloylpropanesulfonic acid, (meth)
Acrylamide, hydroxyalkyl (meth) acrylate, methoxypolyethylene glycol mono (meth) acrylate and the like can be mentioned. Further, an ethylenically unsaturated monomer having a polyoxyalkylene group is particularly preferred.

When two or more ethylenically unsaturated monomers are used in combination as the monomer component, a more preferable combination is, for example, a combination of an alkali metal (meth) acrylate such as sodium acrylate and acrylamide. And a combination of an alkali metal salt of (meth) acrylic acid and methoxypolyethylene glycol mono (meth) acrylate, but are not particularly limited.

By polymerizing the above monomer components,
The water-absorbent resin (a) is obtained. In addition, the water absorbent resin (a)
The average molecular weight, shape, average particle size, etc. of the resin may be set according to the composition of the coating material for the friction reducing agent, the type of the binder, the physical properties, the working environment, etc., and are not particularly limited. The average particle size of a) is preferably 30 to 800 μm, more preferably 30 to 600 μm, and 30 to 400 μm.
μm is most preferred.

When the average particle diameter of the water-absorbent resin (a) used in the present invention exceeds 800 μm, the particle diameter is too large, and the water-absorbent resin (a) is added to the solvent (c) solution of the hydrophilic binder resin (b). When mixed, the particles of the water-absorbent resin (a) tend to settle, which is not preferable.

On the other hand, if the average particle diameter of the water-absorbent resin (a) is less than 30 μm, handling becomes extremely difficult (e.g., it tends to be scattered as fine powder), which is not preferable.

Next, the hydrophilic binder resin (b) constituting the paint for a friction reducing agent of the present invention will be described.

The hydrophilic binder resin (b) used in the present invention is water-soluble or water-swellable, has a function of fixing the water-absorbent resin (a) to the substrate as a binder, and has a solvent ( Although it is not particularly limited as long as it dissolves in c), for example, (meth) acrylate copolymer, polyurethane, polyester, polycarbonate, polyvinyl alcohol-based resin, polyvinyl acetate partial hydrolyzate, Examples thereof include an ethylene-polyvinyl alcohol copolymer, and a mixture of one or more of these can be used.

If the hydrophilic binder resin (b) has too low hydrophilicity, the swelling of the water-absorbent resin (a) is hindered, the absorption of soil moisture is reduced, and the friction reduction of the friction reducing agent paint is reduced. It is not preferable because the function is deteriorated. on the other hand,
If the hydrophilicity of the hydrophilic binder resin (b) is too high, the adhesion of the binder to the base material is too low when water in the soil is absorbed, and the entire coating film is undesirably peeled off too quickly. For the reasons described above, the hydrophilic binder resin (b) preferably has an appropriate hydrophilicity.

The acid value of the hydrophilic binder resin (b) is preferably 40 mgKOH / g or more, more preferably 50 mgKOH / g or more, and 70 mgKOH / g or more in order to have a suitable hydrophilicity. Things are even more preferred.

The acid value of the hydrophilic binder resin (b) is 40
If it is less than mgKOH / g, the hydrophilicity becomes too low, which is not preferable. Further, in order to maintain the binder content at the time of water absorption, it is preferably at most 500 mgKOH / g, more preferably at most 300 mgKOH / g, even more preferably at most 200 mgKOH / g. Acid value of hydrophilic binder resin (b) is 500mg
If it exceeds KOH / g, the hydrophilicity becomes too high, which is not preferable.

Next, the glass transition temperature of the hydrophilic binder resin (b) is not particularly limited, but the adhesion to the substrate, the workability of embedding the substrate in the soil, and the use of a friction reducing agent From the viewpoint of compatibility of the toughness of the paint film, -20 ° C to 12 ° C
It is preferred to have a glass transition temperature at 0 ° C. When the glass transition temperature is −20 ° C. or lower, the coating film for the friction reducing agent tends to be sticky, and blocking may occur particularly when the coated substrates are left standing after being stacked. Further, since the strength of the friction reducing agent coating is insufficient, the base material is easily peeled off when buried in the soil, which is not preferable. From this, it is more preferable that the glass transition temperature is 0 ° C. or higher.

When the glass transition temperature of the hydrophilic binder resin (b) is 120 ° C. or higher, the anti-adhesive layer becomes too hard, and the adhesion to the substrate and the flexibility of the friction reducing agent coating film become poor. Also, when the base material is buried in the soil, the peeling and the falling off of the water-absorbent resin (a) easily occur, which is not preferable. From this, it is more preferable that the glass transition temperature is 100 ° C. or less.
It is more preferable to have a glass transition temperature in each of the ranges of ° C. because the balance between the softening component and the shape maintaining component is good.

The weight average molecular weight (Mw) of the hydrophilic binder resin (b) is not particularly limited, but may be 30,000.
The range of 0 to 300,000 is preferable, and 50,000 to
A range of 200,000 is more preferred. By using the resin having the above-mentioned weight average molecular weight, it becomes easy to balance the toughness of the anti-adhesion material with the solubility in alkaline water.

As the hydrophilic binder resin (b), the hydrophilicity can be easily adjusted by adjusting the acid value or the like.
It is preferable to use an OH / g resin.

Hereinafter, the alkali water-soluble resin of the present invention will be described. The alkali water-soluble resin which is one kind of the hydrophilic binder resin (b) constituting the paint for a friction reducing agent of the present invention is dissolved in a 0.4% by weight aqueous solution of NaOH, and is dissolved in neutral or acidic water. Insoluble resin.
The alkali water-soluble resin is not particularly limited as long as it has the solubility specified above. For example, copolymerization of an α, β-unsaturated carboxylic acid monomer and another monomer copolymerizable therewith. Coalescence can be mentioned.

Although the solubility in the above-described alkaline water is not particularly limited, the preferable solubility of the alkali water-soluble resin as a binder resin which can be preferably used in the present invention will be described later. . In addition, the term “alkali water-soluble resin” of the present invention may be expressed as an alkali-soluble resin in another expression. Since it is more clear to use an alkali water-soluble resin,
In the present invention, an alkali water-soluble resin is used.

The solubility of the alkali water-soluble resin which can be preferably used in the present invention in alkaline water is not particularly limited as long as the characteristics of the present invention are not impaired.

The alkaline water-soluble resin of the present invention includes
This value is preferably between 50% and 100%. More preferably, it is 60-100%. More preferably, it is 70-100% by weight. If no resin remains after filtration, the resin is dissolved.

The method for producing the alkaline water-soluble resin and the hydrophilic binder resin having an acid value of 40 to 500 mgKOH / g of the present invention is not particularly limited, but the following α, β-unsaturated carboxylic acid monomer and A copolymer obtainable by polymerization using an unsaturated monomer component comprising a monomer other than the polymerizable α, β-unsaturated carboxylic acid monomer is preferable.

For example, the α, β-unsaturated carboxylic acid monomer used in the production of the alkaline water-soluble resin of the present invention and the hydrophilic binder resin having an acid value of 40 to 500 mgKOH / g includes, for example, acrylic acid Α, β-unsaturated carboxylic acids such as methacrylic acid, maleic acid, itaconic acid and fumaric acid; α, β-unsaturated carboxylic acid anhydrides such as maleic anhydride and itaconic anhydride; maleic acid monoester, fumaric acid Monoesters of α, β-unsaturated dicarboxylic acids such as monoesters and itaconic acid monoesters can be mentioned. The α, β-unsaturated carboxylic acid monomer may be only one kind or two or more kinds.
Of these, acrylic acid and / or methacrylic acid, which are acrylic α, β-unsaturated carboxylic acids, are preferably used because they are inexpensive and have good copolymerizability with other unsaturated monomers.

Next, other monomers copolymerizable with the α, β-unsaturated carboxylic acid monomer include, for example, methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, stearyl acrylate, methyl methacrylate, ethyl methacrylate Esters of monohydric alcohols having 1 to 18 carbon atoms with (meth) acrylic acid, such as methacrylate, propyl methacrylate, butyl methacrylate, and stearyl methacrylate; acrylonitrile;
Nitrile group-containing vinyl monomers such as methacrylonitrile; amide group-containing vinyl monomers such as acrylamide and methacrylamide; hydroxyl-containing vinyl monomers such as hydroxyethyl acrylate and hydroxypropyl methacrylate; glycidyl methacrylate and the like Epoxy group-containing vinyl monomers; metal salts of α, β-unsaturated carboxylic acids such as zinc acrylate and zinc methacrylate; styrene, α
-Aromatic vinyl monomers such as methylstyrene; aliphatic vinyl monomers such as vinyl acetate; halogen-containing vinyl monomers such as vinyl chloride, vinyl bromide, vinyl iodide, and vinylidene chloride; allyl ether Maleic acid derivatives such as dialkyl esters of maleic acid; fumaric acid derivatives such as dialkyl esters of fumaric acid; maleimide derivatives such as maleimide, N-methylmaleimide, stearylmaleimide, N-phenylmaleimide, N-cyclohexylmaleimide; itaconic acid Mono- and dialkyl esters, itaconic amides, itaconic imides, itaconic amide esters and other itaconic acid derivatives; alkenes such as ethylene and propylene; dienes such as butadiene and isoprene; vinyl ethers; 2- (meth) acryloylpropane Sulfone (Salt), 3-allyloxy-2
Examples thereof include unsaturated monomers having a sulfonic acid (salt) group such as hydroxypropanesulfonic acid (salt), polyalkylene glycol (meth) acrylates, and the like, and one or more of these are used. be able to.

Among these, as the alkyl (meth) acrylate, esters having various properties can be easily obtained, and by appropriately combining them, the Tg (hardness, softness) of the binder resin can be obtained. It is preferable because the adhesion to the substrate can be easily adjusted and the copolymerizability with the α, β-unsaturated carboxylic acid monomer is relatively good.

The above alkyl (meth) acrylate is used in an amount of from 30% by weight to 1% by weight based on 100% by weight of the total amount of other monomers copolymerizable with the α, β-unsaturated carboxylic acid monomer.
It is preferably used at 00% by weight, more preferably at least 50% by weight to 100% by weight. More preferably 60 to 100% by weight, even more preferably 70 to 100% by weight.
100% by weight. That is, the use of an acrylic monomer as another monomer is a preferred embodiment as a form of the alkali water-soluble resin as the hydrophilic binder resin (b) of the present invention.

The ratio of the above-mentioned α, β-unsaturated carboxylic acid monomer and the unsaturated monomer component comprising another monomer copolymerizable therewith is not particularly limited.
When the unsaturated monomer component comprising an unsaturated carboxylic acid monomer and another monomer copolymerizable therewith is defined as 100% by weight, α, β-unsaturated carboxylic acid in all monomer components is The proportion is preferably 7 to 80% by weight based on the total amount of the unsaturated monomer. More preferably, it is 7 to 50% by weight. More preferably, it is 9 to 30% by weight.

The proportion of the α, β-unsaturated carboxylic acid monomer in all the monomers in the alkali water-soluble resin is 7% by weight.
When it is less than 3, hydrophilicity tends to be too low due to low acid value. When the ratio exceeds 80% by weight,
Problems tend to occur when the hydrophilicity is too high.

Use as a raw material for producing a hydrophilic binder resin having an acid value of 40 mgKOH / g or more and 500 mgKOH / g or less, that is, a binder resin obtained by polymerizing the above unsaturated monomer component of the present invention. Α
The amount of the copolymerizable monomer other than the β-unsaturated carboxylic acid monomer is determined by the amount of the above-mentioned α, β-unsaturated carboxylic acid monomer and another monomer copolymerizable therewith. Assuming that the total amount of the saturated monomer is 100% by weight, preferably 93 to 20% by weight of the total amount of the unsaturated monomer. More preferably, it is 93 to 50% by weight. More preferably, it is 91 to 70% by weight.

When the proportion of the α, β-unsaturated carboxylic acid monomer is less than 20%, the hydrophilicity becomes low, and when it exceeds 93%, the hydrophilicity becomes too high, which is not preferable.

The method for producing the alkali water-soluble resin is not particularly limited, and generally known polymerization methods such as solution polymerization, bulk polymerization, emulsion polymerization and suspension polymerization can be used. Among them, solution polymerization in an organic solvent is preferred. It is preferred to manufacture.

This is because the water-absorbing resin can be mixed with the solution or dispersion containing the alkali-water-soluble resin obtained by the solution polymerization as it is, thereby making it possible to produce the friction reducing agent coating of the present invention. It is.

The polymerization forms include radical polymerization,
Examples thereof include anionic polymerization, cationic polymerization, and coordination polymerization, and radical polymerization is preferable as an industrial production method.

Examples of the reaction vessel used for producing the starting polymer include a tank reactor, a kneader, and a tubular reactor such as a static mixer. These reactors can be used together if necessary. A dropping tank is also used as needed. The pressure in the reaction vessel may be any of reduced pressure, normal pressure, and pressurized.

Next, the radical polymerization initiator used in the radical polymerization is not particularly limited, but specific examples thereof include 2,2′-azobisisobutyronitrile,
Examples include azo initiators such as 2,2'-azobis (2,4-dimethylvaleronitrile); and peroxide initiators such as benzoyl peroxide and di-t-butyl peroxide. These radical polymerization initiators are 2
More than one type may be used in combination.

The solvent used in the solution polymerization is not particularly limited as long as it does not hinder the radical polymerization reaction.
For example, alcohols such as methanol, ethanol and isopropyl alcohol; aromatic hydrocarbons such as benzene and toluene; ketones such as acetone and methyl ethyl ketone; aliphatic esters such as ethyl acetate and butyl acetate;
Examples thereof include ethylene glycol derivatives such as ethylene glycol and ethylene glycol monomethyl ether, and propylene glycol derivatives such as propylene glycol monomethyl ether and propylene glycol monomethyl ether acetate. Two or more of these solvents may be used in combination.

Next, the solvent (c) used in the present invention will be described. The solvent (c) can be used without particular limitation as long as it is a known solvent used for ordinary paints and the like. For example, one or more of the solvents exemplified in the description of the method for producing the alkali water-soluble resin or the like can be used. It can be used in combination of two or more.

As a method for selecting the solvent (c), it is preferable to select a solvent having a boiling point, safety and the like suitable for application to a substrate. If a solvent having a low boiling point is selected, it has a quick drying property, and a coating film can be formed in a short time, so that a thick coating or the like can be easily performed. If a solvent having a high boiling point is selected, the working time can be lengthened. By using an organic solvent as a medium, there is no swelling due to water absorption of the water-absorbent resin that occurs when a medium containing water is used, and the coating operation is facilitated because the resin does not become a gel. In addition, when a highly volatile solvent such as methyl ethyl ketone or methanol is used, it is dried in about 10 minutes, and since it dries much faster than when water is used as a medium, it is possible to quickly shift to the next operation or process. The work period or the time required for application to the substrate can be significantly reduced.

The paint for a friction reducing agent of the present invention impairs its characteristics if it contains the water-absorbent resin (a), hydrophilic binder resin (b) and solvent (c) described above as essential components. As long as the additives (h) are not included, other resins, pigments, various stabilizers, various fillers, and the like may be included.

The ratio of the water-absorbent resin (a), hydrophilic binder (b) and solvent (c) to other additives (h) is not particularly limited. In order to exert the effect, the weight ratio ([(a) + (b) + (c)] /) of the total of the sum of the water absorbent resin (a), the hydrophilic binder (b) and the solvent (c)
[(A) + (b) + (c) + (h)] × 100 (%). ) Is preferably 50% or more, more preferably 70% or more, and most preferably 80% or more.

The ratios of the water-absorbent resin (a), hydrophilic binder (b), solvent (c) and other additives (h) are not particularly limited. In order to regret, the water-absorbent resin (a) is 5 to 60% by weight, and the hydrophilic binder (b) is 10 to 70% by weight.
% By weight, the solvent (c) is preferably 5 to 70% by weight, and the other additive (h) is preferably 0 to 50% by weight.
Is 10 to 50% by weight, and the hydrophilic binder (b) is 10 to 50% by weight.
More preferably, the content of the solvent (c) is 10 to 60% by weight, and the content of the other additive (h) is 0 to 30% by weight.

The method of applying the coating material for a friction reducing agent of the present invention to various substrates is not particularly limited as long as it is a known coating method. For example, a brush or a roller may be used. Spray painting may be performed using a spray device such as ricin gun.

The substrate to which the present invention is applied is not particularly limited as long as it is a known substrate used in the latent box method and the propulsion method. For example, pipes such as steel pipes and fume pipes,
Piles such as steel sheet piles (sheet piles), corrugated sheets, H-shaped steels, I-shaped steels, steel pipe piles, iron columns, concrete piles, poles, etc., various tanks mainly used in the submersion method, and water storage tanks.

One of the important features of the coating material for a friction reducing agent of the present invention is that the friction reducing agent layer can be supplied gradually.

The mechanism is that the water absorption of the paint film for the friction reducing agent gradually progresses from near the surface, so that the hydrophilicity of the hydrophilic binder (b) and the hydrophilicity of the water-absorbent resin (a) and the hydrophilic binder By appropriately adjusting the ratio of (b), it is possible to set a desired water absorption rate under each construction condition, and therefore, from the surface of the friction reducing agent paint film applied to the base material surface, By absorbing a suitable amount of water therein, a new friction-reducing agent layer (water-absorbing and swelling layer) is supplied to the surface of the substrate for many days.

For example, a specific example of sustained release is shown below.
It is as follows. The friction reducing agent of the present invention is applied to a substrate 1 (for example, a steel pipe), and only a part of the surface is absorbed and swelled to form a friction reducing agent layer 1, and then the substrate 1 (for example, a steel pipe 1) is formed. Is poured into the soil (day 1), the friction reducing agent layer 1 functions as a friction reducing agent, and peels off from the surface of the substrate 1 (for example, the steel pipe 1).

However, by the construction on the next day, the surface of the base material near the surface of the friction reducing agent absorbs water in the soil and swells to form a new friction reducing agent layer 2. Further, on the second day, when the base material 2 (for example, the steel pipe 2) is cast from the ground in the same manner as yesterday, and the base material 1 (for example, the steel pipe 1) is further pushed deep into the soil, the friction reducing agent layer 2 Functions as a friction reducing agent and peels off from the substrate 1 (for example, the steel pipe 1).

By repeating this phenomenon, even in the case of a base material (for example, a steel pipe, etc.) such as a propulsion method in which the casting is repeated in the soil for many days, the paint for a friction reducing agent of the present invention can be used on the ground. It is possible to exhibit the friction reducing function in the soil throughout the construction only by applying it once to the base material.

[0065]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the invention is limited thereto. The acid value of the hydrophilic binder resin (b) is J
It was measured based on the test method described in the application clause 4.3 of IS K6901 “Test method for liquid unsaturated polyester resin”. However, when the hydrophilic binder resin (b) did not dissolve in the solvent specified in the test method, the measurement was carried out in accordance with the above test method, using a suitable solvent to dissolve the hydrophilic binder resin.

The glass transition temperature of the hydrophilic binder resin (b) was measured by using DSC 22 manufactured by Seiko Instruments Inc.
JIS K 7121 under a nitrogen atmosphere using 0C
Measurement method of plastic transition temperature ".
In addition, the condition adjustment of the test specimen was performed according to 3. According to (3).

The solubility of the alkaline water-soluble resin in the present invention in alkaline water was determined by the weight reduction rate of the alkaline water-soluble resin in the following solubility test. Specifically, the molded product of the alkali water-soluble resin of the present invention having a size of 5 mm or less (for example, a pellet shape of 3 mm as in Examples or a size of 5 mm square or less even if it is not pelletized). Cut, etc.) 10 g
Was added to 500 g of an aqueous solution of 0.4% by weight of NaOH, and the mixture was stirred at 25 ° C. for 24 hours. I asked for it.

That is, if there is any resin remaining without being dissolved after stirring for 24 hours, the resin is filtered off, washed with water, and the weight after drying is determined. Before being subjected to the solubility test, it can be determined by a reduction rate from the weight of the original alkali water-soluble resin. That is, <original weight−weight after solubility test> / <
Original weight> was determined in% of the ratio. If there is no resin remaining after the filtration, the evaluation is that the resin is dissolved.

[Production Example 1] A water-absorbing resin was prepared by the following method. That is, a kneader equipped with a table-top jacket having a capacity of 1.5 L and provided with a thermometer and a blade (stirring blade), the inner surface of which is lined with ethylene trifluoride, was used as a reactor, and methoxypolyethylene glycol methacrylate was used as the reactor. (Molecular weight 512) 55.18 g, methacrylic acid (molecular weight 86.09) 3.76 g, sodium methacrylate (molecular weight 108) 215.69 g, polyethylene glycol diacrylate 1.4 as a crosslinking agent
g, and 352.37 g of ion-exchanged water as a solvent were charged. The ratio of the crosslinking agent in the monomer component is 0.15
Mol%.

By flowing warm water of 50 ° C. through the jacket, the above aqueous solution was stirred under a stream of nitrogen gas for 50 hours.
Heated to ° C. Next, 2,2′-azobis- (2-amidinopropane) dihydrochloride (molecular weight 2
71.27, Chemical product V-50 manufactured by Wako Pure Chemical Industries, Ltd.)
Was added and stirred for 10 seconds, then the stirring was stopped and the mixture was allowed to stand. The ratio of the polymerization initiator to the monomer component is 0.2 mol%.

The polymerization reaction was started immediately after the addition of the polymerization initiator, and the internal temperature reached 100 ° C. (peak temperature) after 90 minutes. Thereafter, the contents were aged for 30 minutes while flowing warm water of 80 ° C. through the jacket. Thus, a hydrogel was obtained. After completion of the reaction, the hydrogel was disintegrated by rotating a blade until the hydrogel became fine, and then the hydrogel was taken out by inverting the reactor.

The obtained hydrogel was dried at 140 ° C. for 3 hours using a hot-air circulation dryer. After drying, the dried product was pulverized using a desktop simple pulverizer (manufactured by Kyoritsu Riko Co., Ltd.). Thus, a water-absorbent resin (1) having an average particle size of 150 μm was obtained.

[Production Example 2] Hydrophilic binder resin (b)
Was prepared by the following method.

That is, a capacity 5 having a thermometer and a dropping device
0.45 kg of acrylic acid, 2.4 kg of ethyl acrylate, 0.15 k of methyl methacrylate
g, 2,2′-azobis- (2,4-
12 g of dimethylvaleronitrile) and 3 kg of methyl alcohol as a solvent were charged. In addition, 1.05 kg of acrylic acid, methyl acrylate 2.1
kg, 3.85 kg of methyl methacrylate, 28 g of 2,2′-azobis- (2,4-dimethylvaleronitrile),
And a mixed solution consisting of 7 kg of methyl alcohol was charged.

The above methyl alcohol solution was heated to 65 ° C. with stirring in a nitrogen gas atmosphere, and reacted for 20 minutes. Thereby, the polymerization rate of the content was adjusted to 72%. Subsequently, while maintaining the internal temperature at 65 ° C., the above mixed solution was dropped uniformly from the dropping device over 2 hours. After completion of the dropwise addition, the content was aged at 65 ° C. for another 3 hours. After completion of the reaction, 33 kg by weight of the hydrophilic binder resin (1) is mixed by mixing 10 kg of methyl alcohol with the content.
A methyl alcohol solution was obtained.

The obtained hydrophilic binder resin (1) has a weight average molecular weight of 130,000 and an acid value of 117 mg KOH.
/ G. As a result of performing differential scanning calorimetry on the hydrophilic binder resin (1), the hydrophilic binder resin (1) had two glass transition temperatures in the range of -80 ° C to 120 ° C. Further, the obtained methyl alcohol solution of the hydrophilic binder resin 1 was desolvated using a twin screw extruder to obtain cylindrical pellets having a diameter of 3 mm and a length of 3 mm. 0.4% by weight of 10 g of the pellets in a beaker
500 g of an aqueous solution of sodium hydroxide having a concentration was added at room temperature, and the mixture was stirred with a magnetic stirrer, and completely dissolved after 4 hours.

[Production Example 3] Hydrophilic binder resin (b)
Was prepared by the following method. That is, acrylic acid was added to a 50 L capacity reactor equipped with a thermometer and a dropping device.
525 kg, 1.725 kg of methyl acrylate, 2.4 kg of ethyl acrylate, 2.85 k of methyl methacrylate
g, 2,2′-azobis- (2,4-
30 g of dimethylvaleronitrile) and 15 kg of methyl alcohol as a solvent were charged.

The above methyl alcohol solution was heated to 65 ° C. with stirring in a nitrogen gas atmosphere, and reacted for 5 hours. Thereby, a 33% by weight methyl alcohol solution of the hydrophilic binder resin (2) was obtained. The weight average molecular weight of the obtained binder resin is 110,000 and the acid value is 51 mgK.
[Example 1] 50% by weight of the water-absorbent resin produced in Production Example 1 and a 33% by weight methyl alcohol solution 15 of the hydrophilic binder resin (1) produced in Production Example 2
By mixing and dispersing with 0 parts by weight, a paint 1 for a friction reducing agent according to the present invention was obtained. Then, the obtained paint (1) for a friction reducing agent is uniformly applied to the surface (both inside and outside) of a steel pipe having a thickness of 1 mm, a diameter of 50 mm, and a length of 500 mm so that the thickness when dried becomes 200 μm. Painted. After 1 hour of natural drying, the coating film had sufficient strength, and was not easily peeled off even when strongly rubbed with an iron spatula.

The steel pipe coated with the coating material for friction reducing agent (1) thus obtained was first immersed in ion-exchanged water for 10 minutes. The surface of the steel pipe after the immersion was slimy covered with the water absorbing and swollen friction reducing agent layer.

Next, this steel pipe is erected vertically on the ground on the premises of our company (Suita City, Osaka Prefecture), and a 3 mm thick
A steel pipe of 0 mm × 60 mm was placed on the steel pipe, and a steel pipe was poured into the soil by hitting it 10 times from a height of 60 cm with a 500 g hammer. Table 1 shows the depth cast from the ground at this time. The steel pipe was left for one day, and the next day, about 500 ml of ion-exchanged water was first applied to the surface (both inside and outside) of the steel pipe, and left for about 10 minutes. The steel pipe surface after standing was covered with the water absorbing and swollen friction reducing agent layer and was slimy. Next, a steel pipe was poured into the soil in the same manner as on the first day.
At this time, the depth of the casting from the surface is shown in Table 1. Further, the steel pipe was allowed to stand for one day, and was driven by the same operation as on the second day. The depth of the steel pipe from the ground surface is shown in Table 1.

In the above experiment, the depth cast from the ground surface over the three days was significantly larger than that without the application of the friction reducing agent paint (1), and the depth was hardly changed during the three days. . Looking at this result,
It can be seen that by applying the friction reducing agent coating material (1) of the present invention to the surface of the substrate, the friction reducing agent layer was supplied to the surface of the substrate over 3 days, and the friction reducing effect was exhibited.

Example 2 The same operation as in Example 1 was carried out except that the applied thickness (when dried) of the coating material for the friction reducing agent was 400 μm, and the depth that was cast for 3 days at that time was used. Are shown in Table 1.

In the above experiment, the depth cast from the ground surface over the three days was significantly larger than that without the application of the friction reducing agent paint (1), and the depth was hardly changed during the three days. . Looking at this result,
Similarly to the result of Example 1, by applying the friction-reducing agent coating material (1) of the present invention to the substrate surface, the friction-reducing agent layer is supplied to the substrate surface over three days, and the friction-reducing effect is obtained. It can be seen that was exhibited.

[Example 3] In Example 1, except that the same amount of the hydrophilic binder resin (2) was used instead of the hydrophilic binder resin (1), and the friction reducing agent paint (2) was used. The same operation was performed, and the depth of the casting for three days is shown in Table 1.

In the above experiment, the depth cast from the ground surface over the three days was significantly larger than that without the application of the friction reducing agent paint (2), and the depth was hardly changed over the three days. . Looking at this result,
Similarly to the results of Examples 1 and 2, by applying the friction-reducing agent coating material (2) of the present invention to the substrate surface, a friction-reducing agent layer was supplied to the substrate surface over three days, thereby reducing friction. It can be seen that the effect was exhibited.

Comparative Example 1 The same operation as in Example 1 was carried out except that the paint (1) for a friction reducing agent was not applied.
Table 1 shows the depth of the casting for three days.

In the above experiment, the depth cast from the ground surface over the three days was significantly smaller than that obtained by applying the friction reducing agent paint (1). From the results, it is significantly different from Examples 1 to 3, and when the paint (1) for a friction reducing agent of the present invention was not used at all, the efficiency of the operation of placing the base material was extremely low. It turns out that it becomes.

Comparative Example 2 The procedure of Example 1 was repeated, except that the grease (manufactured by Showa Shell Sekiyu KK) was applied at a thickness of 200 μm instead of applying the friction reducing agent coating material (1) at a thickness of 200 μm. Performed the same operation, and Table 1 shows the depths cast for three days.

In the above experiment, the depths cast from the ground surface were almost the same as those applied with the friction reducing agent paints (1) and (2) on the first day. The day was significantly smaller than the first day, and was almost the same as that without any application. As can be seen from these results, when grease is applied, the friction reducing effect is temporary without any sustained release, and is significantly different from Examples 1 to 3, and it is apparent from the second day and thereafter. Shows that almost no friction reducing agent effect appears.

[0090]

According to the present invention, a submersion method for burying various tanks and water storage tanks in the ground or a propulsion method for burying (horizontal and vertical) various fume pipes, steel pipes, steel pipe piles, etc. in the ground. At this time, a paint for a friction reducing agent for a latent box method or a propulsion method containing the water-absorbent resin (a), the hydrophilic binder resin (b) and the solvent (c) of the present invention as essential components is prepared by using various tanks, water tanks, By pre-coating on fume pipes, steel pipes, steel pipe piles (base material), etc., absorb water from the soil throughout the construction period, and gradually release the substrate surface when buried in the ground By supplying a friction-reducing agent layer between the soil and the soil, the friction can be reduced and burying can be facilitated (speed-up of burying, reduction of pushing force at the time of burying, etc.).

[0091]

[Table 1]

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI C10M 107/28 C10M 107/28 107/32 107/32 107/34 107/34 107/38 107/38 107/42 107/42 107/44 107/44 107/46 107/46 111/04 111/04 E02D 9/00 E02D 9/00 E21D 9/06 311 E21D 9/06 311Z // C10N 20:00 C10N 20:00 Z 40:00 40:00 Z 50:02 50:02 (56) References JP-A-63-165615 (JP, A) JP-A-4-16618 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , (DB name) E02D 5/00 C09D 5/00 C09D 201/00 C10M 107/24 C10M 107/26 C10M 107/28 C10M 107/32 C10M 107/34 C10M 107/38 C10M 107/42 C10M 107/44 C10M 107 / 46 C10M 111/04 E02D 9/00 E21D 9/06 311 C10N 20:00 C10N 40:00 C10N 50:02

Claims (5)

(57) [Claims] 1. A friction reducing agent paint for a latent box method or a propulsion method, comprising a water absorbing resin (a), a hydrophilic binder resin (b) and a solvent (c) as essential components . Paint forms a friction reducing agent layer on the substrate surface
To reduce the friction between the base material and the ground (soil).
The friction reducing agent layer is provided between the surface of the base material and the ground (soil).
A paint for a friction reducing agent, which is supplied in a sustained release manner . 2. The friction-reducing agent coating according to claim 1, wherein the hydrophilic binder resin (b) is an alkali water-soluble resin. 3. The hydrophilic binder resin (b) having an acid value of 4
The coating material for a friction reducing agent according to claim 1, wherein the coating amount is 0 to 500 mgKOH / g. 4. The friction-reducing agent coating according to claim 1, wherein the water-absorbent resin (a) is a salt-resistant water-absorbent resin. 5. A latent box method or a propulsion method using the paint for a friction reducing agent according to any one of claims 1 to 4.