JP2000280231A - Manufacture of setting filler using water-absorbing polymer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To develop a water absorbing performance of a water absorbing polymer proper by a method wherein prior to mixing with a setting material, a water absorbing polymer is firstly mixed with water or accelerator-mixed water and thereafter, a setting material is charged and mixed by kneading. SOLUTION: Prior to mixing with a setting material, a water-absorbing polymer is mixed with water or an accelerator-mixed aqueous solution. The water-absorbing polymer is sufficiently expanded. Thereafter, the setting material is charged into water and mixed by kneading. Then, the manufactured setting filler reacts by water absorption in water in a state wherein the water absorbing polymer is low in alkali concentration. Herein, cement or the like as the setting material, that having aluminate or the like as a main material, and polyacrylate crosslinked material or the like as the water absorbing polymer are used. Thereby, a water absorbing performance possessed by the water- absorbing polymer itself can be sufficiently developed, a use amount of an especially high costed water-absorbing polymer can be reduced, and the cost can be extremely decreased.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a curable filler using a water-absorbing polymer, which is suitable for use as a filler for filling a cavity, for example.

[0002]

2. Description of the Related Art As is well known, when a tunnel is excavated in a mountain, a hole is excavated in a bedrock constituting a ground. At this time, cavities due to small-scale collapse easily occur on the inner peripheral surface of the excavated hole, particularly on the top end. Also, NATM
Before the introduction of the (New Austrian Tunneling Method), cavities often occur on the back of the lining of tunnels. Since this cavity is not preferable for the stability of the ground, it is necessary to fill and fill the cavity filler. The cavity filler used in such a case is required to expand inside the cavity after filling and fill the cavity.Conventionally, as such a filler, foamed polyurethane, air mortar, air milk and the like are used. I was

When a tunnel is excavated in the ground using a tunnel boring machine, a shield excavator, or the like, a hole may be excavated in the ground, and a segment or the like may be assembled behind the hole to perform lining. In this case, a gap between the outer peripheral surface of the assembled segment and the inner peripheral surface of the hole is filled with a so-called backing material. It is well known that cement-based materials such as mortar and air mortar are frequently used as such backing material.

However, the materials used as the above-mentioned fillers and backing materials have the following problems. First, foamed polyurethane is expensive as a filler for filling the cavities. On the other hand, since air mortar has a large fluidity, it is difficult to fix it at a specific injection location, that is, to perform so-called limited filling.

[0005] In addition, in the case of a cement-based material such as mortar used as a backing material for a segment, particularly when a tunnel boring machine is used for excavation, even if the backing material is to be filled at the top side of the segment, the tunnel boring machine is not used. Since the tail seal that closes the gap between the segment and the surrounding ground is not usually provided, the filled backing material flows out from the gap between the end of the segment and the surrounding ground, making the operation very difficult. It becomes something.

[0006] In view of the above circumstances, the present inventors,
The technology disclosed in Japanese Patent Application No. 9-247285 has already been proposed.
This technology is a cavity filler composed of a composition containing cement, a water-absorbing polymer, and water, and can obtain high filling properties into cavities and gaps by utilizing the property of the water-absorbing polymer to absorb water and expand. is there.

[0007]

However, the following problems still remain in the technique proposed by the present inventors as described above. That is, the water-absorbing polymer is
As such, it has the ability to absorb more than 100 times the water of the polymer mass. However, it has been found that the water-absorbing polymer is generally susceptible to alkali metal ions, and the water-absorbing performance is significantly reduced in an environment such as in a cement paste. For this reason, the composition material of the cavity filler proposed by the present inventors includes cement, and therefore, the cement is used in a form in which the water absorption performance of the water absorbent polymer is significantly reduced by the cement. Will be. The present invention has been made in view of the above points, and an object of the present invention is to provide a method for producing a curable filler using a water-absorbing polymer that can exhibit the original water-absorbing performance of a water-absorbing polymer. And

[0008]

SUMMARY OF THE INVENTION The present invention relates to a method for producing a curable filler comprising a composition containing a water-absorbing polymer having the property of absorbing water to expand and a curable material such as mortar or cement. Prior to mixing with the curable material, the water-absorbing polymer is first mixed with water or a quick-setting agent mixed water, and then the curable material is mixed with water in which the water-absorbing polymer has already been mixed. It is characterized by being charged and kneaded.

It is effective that the water-absorbing polymer is sufficiently swelled in advance by mixing it with water or an aqueous solution of a quick-setting agent prior to mixing with the curable material.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, an embodiment of a method for producing a curable filler using a water-absorbing polymer according to the present invention will be described.

First, a curable filler using a water-absorbing polymer will be described. The curable filler used in the present invention is composed of a composition containing bentonite, cement, a water-absorbing polymer, a quick-setting agent, and water.

The bentonite used for the curable filler is a clay mainly composed of montmorillonite containing silica and alumina as main components, and has an average particle diameter of 10 to 1%.
00 μm, preferably 30 to 50 μm fine powder,
Rich in water absorption and swelling. Since bentonite has different physical properties and swelling power depending on the place of production, particle size, etc., it should be selected in consideration of these. Preferred examples of bentonite include, for example, products from Wyoming, USA (absorption capacity: 7.5 g / g) and products from Tochigi (4.6 g / g).

The cement used for the hardening filler is generally Portland cement, but other cements such as white cement, alumina cement,
Blast furnace cement or the like can be used alone or in combination with other cements.

As the quick-setting material (admixture) usually used together with cement, a well-known quick-setting material containing, for example, aluminate, calcium chloride, sodium carbonate, sodium silicate or the like as a main component can be appropriately used. .

The water-absorbing polymer is a crosslinked structure of a hydrophilic polymer, and has a property of absorbing water of 10 to 1000 times its own weight and swelling. Usually, it is obtained by polymerizing a water-soluble ethylenically unsaturated monomer in the presence of a cross-linking agent and by cross-linking a water-soluble ethylenically unsaturated monomer into a water-soluble polymer. There are things.

Examples of the water-absorbing polymer include a crosslinked product of poly (meth) acrylic acid or poly (meth) acrylate, a crosslinked product of poly (meth) acrylate having a sulfonic acid group, and a polyalkylene chain. Crosslinked poly (meth) acrylate, crosslinked poly (meth) acrylamide, crosslinked polydioxolane, crosslinked polyethylene oxide, crosslinked polyvinylpyrrolidone, crosslinked sulfonated polystyrene, crosslinked polyvinylpyridine, starch-poly (meth) acrylonitrile graft Saponified copolymer, starch-poly (meth) acrylic acid (and salt thereof) graft-crosslinked copolymer, reaction product of polyvinyl alcohol and maleic anhydride (salt), crosslinked polyisobutylene-maleate copolymer, Polyvinyl alcohol sulfonate, poly Alkenyl alcohol - can be given water-absorbing polymers such as acrylic acid graft copolymers and the like.

In the above, specific examples of the water-soluble ethylenically unsaturated monomer include, for example, acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, citraconic acid, vinyl sulfonic acid, (meth) Allylsulfonic acid, 2- (meth) acrylamide-2-methylpropanesulfonic acid, 2- (meth) acryloylethanesulfonic acid, 2- (meth) acryloylpropanesulfonic acid, (meth) allylsulfonic acid, and alkali metals thereof Salts and ammonium salts; N, N'-dimethylaminoethyl (meth) acrylate and its quaternary compounds;
(Meth) acrylamide, N, N'dimethyl (meth) acrylamide, 2-hydroxyethyl (meth) acrylamide, 2-hydroxyethyl (meth) acrylate,
2-hydroxypropyl (meth) acrylate, hydroxyalkyl (meth) acrylate, polyethylene glycol mono (meth) acrylate, polyalkylene glycol (meth) acrylate, and the like.
Species or a mixture of two or more can be used.

In order to impart particularly high liquid absorption swelling property in a composition containing cement, the above-mentioned monomers, particularly preferably acrylic acid, methacrylic acid, or alkali metal salts or ammonium salts thereof are polymerized with a salt-resistant material. It is preferable to copolymerize a monomer (salt-resistant monomer) that gives a water-absorbing polymer having a high viscosity.

Preferred examples of the monomer (salt-resistant monomer) used for imparting salt resistance to the water-absorbing polymer include, for example, 2- (meth) acryloylethanesulfonic acid and 2- (meth) acryloylpropanesulfone. Water-soluble ethylenically unsaturated monomers having a sulfonic acid group, such as acids, 2- (meth) acrylamido-2-methylpropanesulfonic acid, alkali metal salts and ammonium salts thereof; (meth) acrylamide, (meth) acryloylmorpholine , Diacetone (meth) acrylamide, N-isopropyl (meth) acrylamide, N,
(Meth) such as N'-dimethyl (meth) acrylamide
Acrylamide and its derivatives; polyalkylene glycol (meth) acrylates such as polyethylene glycol (meth) acrylate and methoxypolyethylene glycol (meth) acrylate; hydroxyethyl (meth)
Hydroxyalkyl (meth) acrylates such as acrylate and hydroxypropyl (meth) acrylate; N
-Such as vinylpyrrolidone and N-vinylsuccinimide,
N-vinyl monomers; N-vinyl amide monomers such as N-vinyl formamide, N-vinyl-N-methyl formamide, N-vinyl acetamide, N-vinyl-N-methyl acetamide; and vinyl methyl ether.

Particularly preferred examples of the salt-resistant monomer include acrylamide, methacrylamide, N-vinylacetamide, methoxypolyethylene glycol (meth) acrylate, hydroxyalkyl (meth) acrylate, and 2- (meth) acrylamido-2-methyl. One or more selected from propanesulfonic acid and their alkali metal salts can be mentioned.

As a method of crosslinking, there are a method of polymerizing and crosslinking a crosslinking monomer simultaneously with a hydrophilic monomer and the like, and a method of crosslinking a reactive polymer after obtaining a hydrophilic polymer by polymerization. As such a cross-linking agent, a copolymerizable polyfunctional water-soluble saturated monomer or a compound capable of reacting with a functional group of the monomer can be used. The cross-linking agent may be added in advance to the monomer, or may be added after polymerization.

Examples of the crosslinking agent for obtaining a suitable water-absorbing polymer include, for example, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, and propylene glycol di (meth) acrylate. Acrylate, polyethylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol di (meth) acrylate, N, N-methylenebisacrylamide, triallyl isocyanurate, trimethylolpropane Compounds having two or more ethylenically unsaturated groups in one molecule such as diallyl ether and tetraallyloxyethane; hydroxyethyl (meth) acrylate, glycidyl (meth ) Compounds having one ethylenically unsaturated group and another reactive functional group in one molecule such as acrylate; ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, glycerin, polyglycerin, propylene glycol, diethanolamine , Triethanolamine, polypropylene glycol, polyvinyl alcohol, pentaerythritol, sorbit, glucose, mannitol, mannitol, sucrose, glucose, and other polyhydric alcohols; ethylene glycol diglycidyl ether, glycerin diglycidyl ether, polyethylene glycol diglycidyl ether , Propylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl Ether, 1,6-hexanediol diglycidyl ether,
Examples thereof include polyepoxy compounds such as trimethylolpropane diglycidyl ether, trimethylolpropane triglycidyl ether, and glycerin triglycidyl ether; and alkylene carbonate. One or more of these can be used.

Particularly preferred crosslinking agents for copolymerization include, for example, trimethylolpropane tri (meth) acrylate, N, N-methylenebisacrylamide, polyethylene glycol di (meth) acrylate and the like.

The amount of the crosslinking agent to be used can be appropriately selected according to the type of the monomer and the polymerization conditions. Generally, 0.0005 to 0.02 to 1 mol of all monomers.
It is preferable to use within the molar range. Used amount is 0.0
If the amount of the crosslinking agent is less than 005 mol, the stability of the hydrogel during polymerization or after completion of polymerization tends to be poor. In addition, the amount of soluble matter in the dried product tends to increase. If the amount of the crosslinking agent is more than 0.02 mol, the water absorption capacity tends to decrease.

In producing the water-absorbing polymer by polymerization (copolymerization), it is preferable to use a polymerization initiator.
The polymerization initiator is not particularly limited, and a wide range of initiators is used. For example, persulfates such as sodium persulfate and potassium persulfate; water-soluble azo such as hydrogen peroxide, 2-2′-azobis (2-amidinopropane) hydrochloride, and 4,4′-azobis-4-cyanovalerate Compounds: Organic peroxides such as benzoyl peroxide, lauroyl peroxide, and peracetic acid; Oil-soluble such as azobisisobutyronitrile and 2,2'-azobis (4-methoxy-2,4-dimethylvaleronitrile) Azo compounds and the like can be mentioned. Further, a reducing agent can be used in combination for the purpose of accelerating the decomposition of these polymerization initiators. Examples of such reducing agents include (bis) sulfuric acid (salt), L-ascorbic acid (salt),
Examples thereof include reducing metals (salts) and amines.

The polymerization solvent for producing the water-absorbing polymer by polymerization (copolymerization) is not particularly limited, and an aqueous medium and an organic solvent are usually used. The aqueous medium means water or a mixed solvent of water and an inorganic or organic solvent soluble in water. Examples of the organic solvent that can be dissolved in water include alcohols having 1 to 4 carbon atoms and lower ketone solvents. Examples of the organic solvent include aromatic hydrocarbons such as benzene, toluene, and xylene; alicyclic hydrocarbons such as cyclohexane; and ketones such as acetone and methyl ethyl ketone.

The temperature at the time of polymerization varies depending on the type of initiator used, but a relatively low temperature is preferred because the molecular weight of the crosslinked polymer becomes large. However, for the polymerization to be completed, 2
The temperature is preferably in the range of 0 ° C to 100 ° C.

The concentration of the monomer in the polymerization system is not particularly limited, but is preferably in the range of 20 to 80% by weight, particularly 30 to 60% by weight in consideration of the controllability of the polymerization reaction and the yield and economy. It is preferred to be within. Although various forms can be adopted as the polymerization form, there are methods such as reversed-phase suspension polymerization, aqueous casting polymerization, and polymerization while subdividing the gel-like hydrated polymer by the shearing force of a double-arm kneader (Japanese Patent Laid-Open No. 57-34101). No.).

Preferred commercial products of the water-absorbing polymer include, for example, trade names "AQUALIC CA" and "AQUALIC CS" (all manufactured by Nippon Shokubai Co., Ltd.). Aqualic CS is a particularly preferred water-absorbing polymer because of its excellent salt resistance.

The curable filler of the present invention may contain, in addition to the above-mentioned components, additives generally used in this field, for example, sand, crucifixion, clay, clay, fly and the like used as aggregate. Ash, perlite, vermiculite, etc., inorganic powders such as calcium carbonate, finely powdered silica, alumina, etc., or inorganic or organic fibrous substances such as wood flour, pulp, water-absorbent fiber, glass fiber, carboxymethylcellulose, hydroxyethylcellulose , A polyvinyl alcohol, a polyacrylamide or other natural or synthetic thickener, and / or a water-soluble organic solvent.

The above-mentioned curable filler is described in detail in Japanese Patent Application No. 9-247285 proposed by the present applicant. For example, the flow value of the composition is adjusted within the range of 140 to 210. Is preferred. This flow value is a value measured based on JIS R5201 for the composition 5 minutes after the start of kneading. By adjusting the flow value to be in the range of 140 to 210, it is possible to perform injection by pumping while being plastic, and the slurry after injection remains at the casting site, which is suitable for limited injection. In other words, it becomes easy to fill up against the gravity, and as a result, it reaches the top end of the void generated between the artificial structure in the tunnel etc. and the rock or ground,
Filling can be performed reliably and efficiently. From this viewpoint, the flow value is more preferably adjusted within the range of 140 to 180.

Such a curable filler is used, for example, as a filling for voids and cavities generated between an artificial structure such as a tunnel and a bedrock, that is, as a backing filler for a tunnel or the like.

Next, a method for producing the above-mentioned curable filler will be described. To produce a curable filler consisting of a composition comprising bentonite, cement, a water-absorbing polymer, a quick-setting agent and water, the water-absorbing polymer is mixed with water before the cement is mixed with water. . For example, it is most effective to first mix the water-absorbing polymer with water at a predetermined mixing ratio, and then mix the water mixed with the water-absorbing polymer with materials such as bentonite, cement, and quick-setting admixture. . Further, first, the water-absorbing polymer and the quick-setting admixture may be mixed in water at a predetermined mixing ratio, and then bentonite, cement, or the like may be added thereto and mixed. Of course, the intention of the present invention is to mix the water-absorbing polymer with water in an environment having a low alkali concentration, and if the water-absorbing polymer is mixed with water prior to cement, other bentonite or quick-setting may be used. It does not matter about the order of mixing the agents and the like.

The curable filler thus produced is
Since the water-absorbing polymer undergoes a water-absorbing reaction in water having a low alkali concentration, the water-absorbing polymer sufficiently exhibits its own water-absorbing performance and expands by absorbing water.

Next, the flow values of the curable filler produced as described above and the curable filler produced conventionally are compared, and the results are shown.

FIG. 1 shows the results of the comparison. In this case, two types of cement, blast furnace cement B and ordinary cement, were compared. As a result, as described above, the curable filler produced by first putting the water-absorbing polymer into water (in the figure, described as "pre-kneading") and the conventional bentonite, cement, water-absorbing polymer, Blast furnace cement B was used with a curable filler (indicated as "simultaneous kneading" in the figure) manufactured by adding a quick-setting agent to water almost simultaneously.
Regardless of the type of seed or ordinary cement, the flow value in the case of "first kneading" is lower than that of "simultaneous kneading", and the lower flow value means that the curable filler is hard. It was found that the water absorption by the water-absorbing polymer was high.

In actual construction, since the curable filler is continuously and repeatedly batch-manufactured a plurality of times by the mixer, the curable filler is kneaded and mixed once, and the mixture is supplied to the mixer. It is conceivable that about 10 to 20% of the curable filler remains. Therefore, assuming such a case, the curable filler of about 16% is left in the mixer, and the curable filler of the next batch is manufactured by "first kneading" in this mixer (in FIG. Kneading repeatedly "
Notation). As a result, even in such a case, the flow value is slightly increased, and the effect of "kneading" tends to be slightly reduced, but a sufficient effect is recognized as compared with "simultaneous kneading".

In the above-described method for producing a curable filler using a water-absorbing polymer, the water-absorbing polymer is first mixed with water, and then the cement is poured into water and kneaded. Thereby, when mixing the water-absorbing polymer, a large amount of alkali metal ions from the cement does not exist in the water, and the water-absorbing performance of the water-absorbing polymer itself can be sufficiently exhibited. As a result, even if the same amount of expansion is achieved, a conventional water-absorbing polymer of, for example, about 1/4 or less may be introduced, and the cost is greatly reduced by reducing the amount of the expensive water-absorbing polymer used. Can be reduced.

In the above embodiment, the use of the curable filler produced by applying the method for producing the curable filler using the water-absorbing polymer according to the present invention is described in the above embodiment. It is not limited to backfilling materials such as tunnels and the like, and can be used in place of ordinary mortar or cement when water absorption or expandability is required. Further, in the above-described embodiment, the configuration in which the curable filler is manufactured in the mixer is described. However, as described in Japanese Patent Application No. 9-247285 already filed by the present applicant, the filling is performed. It is also possible to adopt a configuration in which water is supplied to a cavity or the like and a material such as cement is mixed in the cavity. Of course, also in this case, it goes without saying that the water-absorbing polymer is mixed with water prior to the introduction of cement or the like.

Other than this, any configuration may be adopted as long as it does not deviate from the gist of the present invention, and it is needless to say that the above-mentioned configurations may be appropriately selectively combined. No.

[0041]

As described above, according to the method for producing a curable filler using a water-absorbing polymer of the present invention, the water-absorbing polymer is first added to water or a quick-setting agent mixed water prior to the curable material. Mixing, and then, the curable material is put into water and kneaded. Thus, when the water-absorbing polymer is mixed, the water has a low alkali metal salt concentration, and the water-absorbing polymer itself can sufficiently exhibit the water-absorbing performance. As a result, the amount of the particularly expensive water-absorbing polymer can be reduced and the cost can be significantly reduced.

[Brief description of the drawings]

FIG. 1 shows a curable filler produced by applying a method for producing a curable filler using a water-absorbing polymer according to the present invention;
It is a figure which shows the comparison result of the property with the curable filler manufactured by the conventional manufacturing method.

 ──────────────────────────────────────────────────続 き Continuing from the front page (71) Applicant 000115500 Lhasa Industry Co., Ltd. 1-1-1, Kyobashi, Chuo-ku, Tokyo (72) Inventor Toshihiro 38-2-8 Hikaricho, Kokubunji-shi, Tokyo 38 Railway Company Inside the Technical Research Institute (72) Inventor Shinji Konishi 2-8-8 Hikaricho, Kokubunji-shi, Tokyo Inside the Railway Technical Research Institute (72) Inventor Daisuke Tachibana 1-3-2 Shibaura, Minato-ku, Tokyo Shimizu Corporation (72) Inventor Takashi Sato 1-3-2 Shibaura, Minato-ku, Tokyo Shimizu Corporation (72) Inventor Fumihiro Miyase 1-2-3 Shibaura, Minato-ku, Tokyo Shimizu Corporation (72) Inventor Shigeyuki Kono 1-3-2 Shibaura, Minato-ku, Tokyo Shimizu Corporation Inside (72) Hiroshi Odanaka 1-2-2 Uchisaiwaicho, Chiyoda-ku, Tokyo Nippon Shokubai Co., Ltd. (72) Yoshihiko Masuda, Inventor 5-8 Nishiburi-cho, Suita-shi, Osaka Japan Co., Ltd. (72) Kazuhiro Okamura 5-8 Nishi-Maburi-cho, Suita-shi, Osaka Inside Nippon Shokubai (72) Inventor Isao Ota 1-1-1, Kyobashi, Chuo-ku, Tokyo Rasa Kogyo Co., Ltd. (72) Inventor Masao Kishimoto 1-1-1, Kyobashi, Chuo-ku, Tokyo Rasa Kogyo Co., Ltd. (72) Inventor Masao Kuranishi 1-1-1, Kyobashi, Chuo-ku, Tokyo Lhasa Industry Co., Ltd. F-term (reference) 2D055 JA00 KA08 KB10 LA16 4G012 PA23 PB26 4G056 AA08 AA23 CA03 CB23

Claims (1)

[Claims] 1. A method for producing a curable filler comprising a composition containing a water-absorbing polymer having a property of absorbing water and expanding, and a curable material such as mortar or cement, wherein the curable material comprises Prior to mixing, the water-absorbing polymer is first mixed with water or a quick-setting agent mixed water, and thereafter, the curable material is put into water in which the water-absorbing polymer has already been mixed and kneaded. For producing a curable filler using a water-absorbing polymer.