JP2007261920A - Cement composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cement composition having excellent bleeding resistance, which exhibits good flowability when it is applied with shearing force during pump pressure-feeding or the like, but has high thixotropic property (dripping preventing property) even when the amount of water is increased without using a quick-setting agent, and which is less likely to cause bleeding when it is cured and almost free from volume shrinkage after curing. <P>SOLUTION: In a cement composition comprising cement (a) and water (b), the cement composition contains crosslinked acrylic polymer particles (c) and an alkylether-modified cellulose resin (d). In the cement composition, the weight ratios of the contents of respective components are as follows: (a)/(b)=100/40-100/100, (c)/(b)=1/500-1/100, (d)/(b)=1/1,000-1/100, and (c)/(d)=1/1-10/1, and the crosslinked acrylic polymer particles (c) are water-insoluble powder composed of crosslinked acrylic polymer particles containing sulfonic acid group and/or acrylamide group. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a cement composition used in the civil engineering / architecture field, which has high thixotropy (anti-dripping property) even when water is increased without using a quick setting agent, and has excellent breathing resistance during curing. Specifically, the present invention relates to a cement composition that can increase the viscosity after casting of cement milk, cement mortar, or concrete and has excellent breathing resistance.

  In recent years, spray cement has been used as a material for spraying on slopes and inner walls of tunnels to reinforce them. It is common to add a quick setting agent to such cement to cure the sprayed cement in a short time to prevent dripping. However, when the quick setting agent is added to the cement, the usable time becomes extremely short, and if it is not used immediately, it hardens, so a facility for mixing the cement and the quick setting agent is installed in the immediate vicinity of the spraying site. There is a need. However, slopes and tunnel construction sites are often in mountainous areas, and it is often difficult to secure a place to install compounding equipment in the immediate vicinity. Therefore, a spray material that can be used for a long time after blending, specifically, it has fluidity at the time of pumping, and does not flow down after being sprayed, that is, has a high thixotropic property. A spray material that does not require the addition of a binder is desired, but no such spray material has yet been developed.

  On the other hand, as a grout material for filling voids or cavities of concrete structures in the civil engineering / architecture field, fluidity to spread from the inlet to every corner inside the cavity, and after filling, There is a demand for cement, mortar, and the like having fixing properties that do not deviate from gaps such as tunnel inner walls. For this purpose, a grout material that has good fluidity during pumping but has a property of decreasing fluidity after being filled and stopped, that is, a grout material having high thixotropic properties, is still desired. No grout material has been obtained.

Therefore, conventionally, a composition such as cement or mortar added with a holmite-based mineral such as sepiolite or attapulgite as an additive for increasing the viscosity (Patent Document 1), a composition added with lambzan gum (Patent Document 2), What added psyllium seed gum (Patent Document 3), added welan gum (Patent Document 4), added β-1,3 glucan (Patent Document 5), and added hydroxyethyl cellulose (Patent Document) 6) etc. are known.
JP-A-6-264449 JP-A-7-10623 JP-A-7-206498 JP-A-7-208097 JP-A-8-157249 JP-A-8-245255

However, any additive can increase the viscosity of the composition such as cement and mortar, and can have thixotropy (anti-sagging), but at the same time, the fluidity of the composition such as cement and mortar decreases. there were.
Furthermore, the cement / water weight ratio of a general cement composition is 100/40 to 100/50, and in order to increase the fluidity of the cement composition, there is a method of increasing the water ratio or adding a water reducing material. Although used, the method of increasing the ratio of water is more effective and simple. However, if the ratio of water is increased, breathing is likely to occur. As a result, volume shrinkage occurs during curing, adhesion to the sprayed surface is reduced, and voids are generated in the filled cavities. was there.

  That is, the object of the present invention is to improve fluidity when shearing force such as pumping is applied even if water is increased without using a quick-setting agent, but after spraying or after filling and resting. To provide a cement composition which has a property of decreasing the viscosity, that is, high thixotropic property (anti-sagging property), is less likely to cause breathing at the time of curing, and is less likely to cause volume shrinkage after curing. It is in.

  As a result of intensive research to solve the above problems, the present inventors have specified specific crosslinked acrylic polymer particles and specific alkyl ether-modified cellulose resin as specific when using cement and water at a specific ratio. When used in a ratio, it was found that a cement composition having high thixotropic properties, hardly causing breathing, and causing little volume shrinkage after curing was obtained, and the present invention was completed.

  That is, the present invention comprises a cement composition comprising cement (a) and water (b), containing crosslinked acrylic polymer particles (c) and an alkyl ether-modified cellulose resin (d), the content ratio of which is Cement (a) / water (b) = 100/40 to 100/100 (weight ratio), crosslinked acrylic polymer particles (c) / water (b) = 1/500 to 1/100 (weight ratio) Alkyl ether-modified cellulose resin (d) / water (b) = 1/1000 to 1/100 (weight ratio), and crosslinked acrylic polymer particles (c) / alkyl ether-modified cellulose resin (d) = A water-insoluble powder comprising 1/1 to 10/1 (weight ratio), and crosslinked acrylic polymer particles (c) comprising crosslinked acrylic polymer particles containing sulfonic acid groups and / or acrylamide groups. Is There is provided a cement composition characterized by.

  The cement composition of the present invention has good fluidity when shearing force such as pumping is applied even if water is increased without using a quick-setting agent, but after spraying or after filling and resting. Has a property of lowering, that is, high thixotropy (anti-sagging property), hardly causes breathing, and hardly causes volume shrinkage after curing. Therefore, concrete for spraying underground tunnels and other excavations, concrete for repairing and reinforcing existing concrete, spray concrete for stabilizing and covering slopes, and cavities and cracks on the back side of tunnel inner walls, etc. It is widely used in the civil engineering and construction fields as grout materials used for pouring, etc., rock bolt construction methods used for injecting upwards or into ground with cracks, or anchor construction methods, underwater concrete, and plastering materials. In addition, the viscosity after casting of cement milk, cement mortar, or concrete can be increased, and the breathing resistance can be improved.

Next, details necessary for carrying out the present invention will be described in detail.
The cement (a) used in the present invention is an essential component as a hardening developing material. Typical examples include ordinary Portland cement, early-strength Portland cement, white cement, moderately hot Portland cement, sulfate resistant salt. Portland cement, low heat Portland cement, Portland cement such as ultra-high strength Portland cement (jet cement, super cement, SQ cement), various mixed cements such as silica cement, blast furnace cement, fly ash cement, or special cements such as alumina cement and expanded cement There is. Preferred is commercially available ordinary Portland cement. The cement (a) is preferably used in an amount of 40 to 70% by weight in the cement composition.

The water (b) used in the present invention may be any water (b) as long as it does not contain components that inhibit cement hardening, such as tap water, industrial water, and well water.
The cement (a) / water (b) weight ratio of a general cement composition is 100/40 to 100/50, but the cement composition of the present invention has fluidity at the time of pumping. The cement (a) / water (b) must be 100/40 to 100/100 (weight ratio), preferably 100/50 to 100/60 (weight ratio). When cement (a) / water (b) is larger than 100/40, after addition of crosslinked acrylic polymer particles (c) containing sulfonic acid groups and / or acrylamide groups and alkyl ether-modified cellulose resin (d) Since the viscosity of the cement composition becomes too high, the fluidity is lowered and pumping becomes difficult. When cement (a) / water (b) is smaller than 100/100, crosslinked acrylic polymer particles (c) containing sulfonic acid groups and / or acrylamide groups and alkyl ether-modified cellulose resin (d) are used. Even if added, the occurrence of breathing cannot be prevented, and at the same time, the strength after curing becomes too low to be practically usable. Cement (a) / water (b) = 100/50 to 100/60 is preferable because thixotropic properties are good and breathing is less likely to occur.

The crosslinked acrylic polymer particles (c) containing a sulfonic acid group and / or acrylamide group used in the present invention are a sulfonic acid group-containing monomer and / or an acrylamide monomer, and (meth) if necessary. A powder composed of water-insoluble polymer particles obtained by polymerizing acrylic acid monomer and, if necessary, other polymerizable monomers, if necessary, three-dimensionally cross-linking using a cross-linking agent. is there. If necessary, an additive generally used in a polymerization reaction such as a polymerization initiator may be used as long as the effects of the present invention are not impaired. As the monomer and crosslinking agent used for the preparation of the crosslinked acrylic polymer particles (c), those produced by a known method or those commercially available can be used. A known method may be applied as a method for polymerizing these monomers.
The sulfonic acid group-containing monomer is preferably a sulfonic acid group-containing acrylamide monomer represented by the following general formula (4) or (5).

(Wherein R ¹ represents a hydrogen atom or a methyl group, and R ² represents a linear or branched alkylene group having 2 to 4 carbon atoms.)

(In the formula, R ¹ represents a hydrogen atom or a methyl group, R ² represents a linear or branched alkylene group having 2 to 4 carbon atoms, and X represents an alkali metal, alkaline earth metal, or ammonium group. Is shown.)

Examples of the sulfonic acid group-containing acrylamide monomer represented by the general formula (4) include 2-acrylamido-2-methylpropanesulfonic acid, 2-methacrylamide-2-methylpropanesulfonic acid, and the like. it can. Among these, 2-acrylamido-2-methylpropanesulfonic acid is particularly preferable.
Examples of the sulfonic acid group-containing acrylamide monomer represented by the general formula (5) include alkali metal salts such as 2-acrylamido-2-methylpropanesulfonic acid and 2-methacrylamide-2-methylpropanesulfonic acid. , Alkaline earth metal salts, ammonium salts and the like. Examples of the alkali metal salt include sodium salt, potassium salt, lithium salt, and rubidium salt. Examples of the alkaline earth metal salt include calcium salt and magnesium salt. Of these, alkali metal salts such as sodium salt, potassium salt, lithium salt and rubidium salt of 2-acrylamido-2-methylpropanesulfonic acid are particularly preferable.

  Examples of the acrylamide monomer include (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N-methyl (meth) acrylamide, N-isopropyl (meth) acrylamide and the like. Among these, (meth) acrylamide represented by the following general formula (2) is preferable.

(In the formula, R ¹ represents a hydrogen atom or a methyl group.)

  Polymers obtained by polymerizing a mixture of the monomers may self-crosslink without using a crosslinking agent, but crosslinking using a crosslinking agent may result in copolymer particles having excellent water absorption. It is preferable in manufacturing.

Examples of the cross-linking agent include a monomer having two or more ethylenically unsaturated bonds and a compound having two or more functional groups that react with the functional group of the monomer in the monomer mixture. .
Preferred examples of the monomer having two or more ethylenically unsaturated bonds include di (meth) acrylic acid ester, tri (meth) acrylic acid ester, bisacrylamide, and the like.

Examples of di (meth) acrylic acid esters include ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, and di (meth) acrylic acid. And carbamyl esters.
Examples of the tri (meth) acrylic acid ester include trimethylolpropane tri (meth) acrylate and pentaerythritol tri (meth) acrylate.
Examples of bisacrylamide include N, N′-methylenebisacrylamide, N, N′-ethylenebisacrylamide, N, N′-methylenebis (meth) acrylamide, and the like.
Among these, it is preferable to use ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, and N, N′-methylenebis (meth) acrylamide.

  Examples of the compound having two or more functional groups that react with the functional group of the monomer in the monomer mixture include, for example, two or more functional groups that react with the carboxyl group of (meth) acrylic acid. The compound which has is mentioned. Specifically, for example, a compound having two or more epoxy groups, a compound having two or more isocyanate groups, and the like are used, and it is particularly preferable to use a diglycidyl ether compound.

Examples of the compound having two or more epoxy groups include ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, glycerin diglycidyl ether, and polyglycerin diglycidyl ether. Among them, it is preferable to use ethylene glycol diglycidyl ether.
Examples of the compound having two or more isocyanate groups include 2,4-tolylene diisocyanate and hexamethylene diisocyanate.

  The reason why the thixotropic property appears when the crosslinked acrylic polymer particles (c) of the present invention are added to the cement composition is considered as follows. That is, cross-linked acrylic polymer particles that do not have a sulfonic acid group or an acrylamide group as a hydrophilic group and are conventionally used as an additive for cement, such as polymer particles obtained by three-dimensionally cross-linking acrylic acid polymers, In salt water from which ions such as calcium ions in the cement elute even if added to the composition, there is almost no water absorption capacity, so the particle size does not change, the interaction with the cement particles is relatively small, and thixotropic properties However, when the crosslinked acrylic polymer particles (c) containing the sulfonic acid group and / or acrylamide group of the present invention are added to the cement composition, the moisture in the cement composition is absorbed and several tens of times. Thixotropic properties due to the interaction with the surrounding cement particles. It is believed that expression.

  The amount of the crosslinked acrylic polymer particles (c) containing sulfonic acid groups and / or acrylamide groups added to the cement composition of the present invention is (c) / (B) = 1/500 to 1/100 (weight ratio), preferably 1/350 to 1/150 (weight ratio). When (c) / (b) is less than 1/500, the thixotropy of the resulting cement composition becomes too low, and it tends to sag when used as a spraying material, and when used as a cavity filler. There is a possibility that deviation from the gap of the inner wall of the cavity cannot be sufficiently prevented after filling. Moreover, when (c) / (b) is larger than 1/100, the viscosity of the resulting cement composition becomes too high and the fluidity is lowered, so that it is difficult to pump with a pump.

  In addition, the crosslinked acrylic polymer particles (c) used in the present invention preferably have a particle size of 0.1 to 50 μm, and the crosslinked acrylic polymer particles (c) having such a particle size have a particle size of 0.1 to 50 μm. If the addition amount is (c) / (b) = 1/350 to 1/150 (weight ratio) with respect to water (b) in the cement composition, it is more effective for the thixotropic expression of the cement composition. Yes, it is preferable.

The alkyl ether-modified cellulose resin (d) used in the present invention is one obtained by substituting the hydrogen atom of at least a part of the hydroxyl group of the glucose ring in the cellulose with an alkyl group. It is not limited, For example, a linear thing, a branched thing, the thing which has an unsaturated bond, the thing which has a substituent, etc. are pointed out. Among them, the alkyl ether-modified cellulose resin (d) is represented by the following general formula (3), in which hydrogen atoms of at least some hydroxyl groups of the glucose ring in cellulose are substituted with hydroxyalkyl groups or alkyl groups. Those containing a structure are preferred. As such a preferable thing, hydroxyalkyl cellulose and hydroxyalkyl alkyl cellulose can be mentioned, and specifically, for example, hydroxyethyl cellulose (HEC), hydroxypropyl cellulose (HPC), hydroxypropyl methylcellulose (HPMC), hydroxyethyl. Examples include, but are not limited to, methyl cellulose (HEMC), hydroxyethyl ethyl cellulose (HEEC), hydroxybutyl methyl cellulose (HBMC), and the like. In the present invention, as the alkyl ether-modified cellulose resin (d), any one produced by a known method or commercially available can be used. Instead of alkyl ether-modified cellulose resins (d) such as hydroxyalkyl cellulose and hydroxyalkylalkyl cellulose used in the present invention, other cellulose-based resins, for example, all substituents introduced into the hydroxyl group of the glucose ring are all alkyl. When alkyl cellulose such as methyl cellulose or ethyl cellulose, which is the base, is used, the resulting cement composition has a low anti-breathing effect. Therefore, in order to have a sufficient anti-breathing effect, the cement composition of the present invention is incorporated into the cement composition. It is necessary to add alkyl cellulose in an amount exceeding the range. In this case, the fluidity of the cement composition becomes too high, and the thixotropic property is lowered.
In the present invention, substitution with cellulose hydroxyalkyl group or alkyl group refers to substitution of a hydrogen atom of a hydroxyl group on a glucose ring.

(Wherein R ¹ , R ² and R ³ are hydrogen atoms, or the formula C _n H _2n OH, C _m H _{2m + 1} , (C _n H _2n O) ₁ C _n H _2n OH or (C _n H _2n O ) ₁ C _m H _{2m + 1} is represented, l represents an integer of 1 to 10, m and n represent an integer of 1 to 5. Any one of R ¹ , R ² and R ³ is , Not a hydrogen atom or C _m H _{2m + 1} , they may be the same or different.)

The alkyl ether-modified cellulose resin (d) used in the present invention preferably has an average substitution amount (MS) of hydroxyalkyl groups per glucose unit of the cellulose of 0.1 to 4.0, more preferably 0.1. The average substitution degree (DS) of the alkyl group is preferably 2.5 or less, more preferably 2.0 or less because water solubility is good and the effect of preventing breathing is high. Preferably used. When the average substitution amount (MS) of the hydroxyalkyl group is less than 0.1, the hydrophilicity is low, it is difficult to dissolve in water, and the effect of preventing breathing may be remarkably lowered, which is not preferable. Further, when the average substitution amount (MS) of the hydroxyalkyl group is more than 4.0, it is not preferable because the setting delay of cement is likely to occur. When the average degree of substitution (DS) of the alkyl group is more than 2.5, the hydrophobicity becomes too strong, it becomes difficult to dissolve in water, and the effect of preventing breathing may be significantly lowered, which is not preferable.
In the present invention, the average substitution amount (MS) of the hydroxyalkyl group per glucose unit of the cellulose of the alkyl ether-modified cellulose resin (d) and the average substitution degree (DS) of the alkyl group are both within the above preferred ranges. Is preferred.

  The addition amount of the alkyl ether-modified cellulose resin (d) to the cement composition of the present invention is (d) / (b) = 1/1000 to 1/100 (weight) with respect to water (b) in the cement composition. Ratio), preferably 1/500 to 1/200 (weight ratio). When (d) / (b) is less than 1/1000, the resulting cement composition is not sufficiently effective in preventing breathing, and when it is used as a spraying material due to the occurrence of breathing and volume shrinkage, it is coated. When used as a cavity filler, a gap is formed after filling, so that the strength as designed does not appear. Moreover, when (d) / (b) is larger than 1/100, the thixotropy of the resulting cement composition is lowered, and when used as a spraying material, it tends to sag, and when used as a cavity filler There is a possibility that deviation from the gap of the inner wall of the cavity cannot be sufficiently prevented after filling.

  The ratio of the crosslinked acrylic polymer particles (c) containing sulfonic acid groups and / or acrylamide groups and the alkyl ether-modified cellulose resin (d) in the cement composition of the present invention is the sulfonic acid groups and / or acrylamide groups. Cross-linked acrylic polymer particles containing (c) / alkyl ether-modified cellulose resin (d) = 1/1 to 10/1 (weight ratio), preferably 1/1 to 6/1 (weight ratio), By doing so, it is possible to balance fluidity and increase in viscosity after standing. When (c) / (d) is greater than 10/1, the resulting cement composition is not sufficiently effective in preventing breathing, and breathing occurs. Moreover, when (c) / (d) is smaller than 1/1, the thixotropic property of the cement composition obtained will fall.

  Moreover, the cement composition of the present invention is not limited to the above-mentioned components, but is generally used as an additive mixed with cement, for example, sand, earth, gravel, clay used as an aggregate. , Fly ash, bentonite, perlite, vermiculite, etc., inorganic powders such as calcium carbonate, fine powder silica, or inorganic or organic fibers such as wood flour, pulp, water-absorbing fibers, glass fibers, and / or Admixtures such as a foaming agent, a water reducing agent, an AE agent, and a foaming agent may be contained.

  Applications of the present invention include concrete for spraying underground excavations such as tunnels, concrete for repairing / reinforcing existing concrete, and spraying concrete used for stabilizing and covering slopes, the backside of tunnel inner walls, etc. Grouting materials used for injection into cavities and cracks, etc., rock bolt construction methods and injection materials for anchor construction methods used for injection into the upward direction and ground with cracks, underwater concrete, and plastering materials.

  Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples, but the present invention is not limited to these. In the following, all parts and% are based on weight unless otherwise specified. The various properties of the cement composition of the present invention were evaluated by the evaluation methods outlined below.

<Fluidity (according to JIS R5201-1997)>
The fluidity (flow value) of the cement composition was measured by a method based on Japanese Industrial Standard JIS R5201.
(Tool)
(1) Flow cone (metal flow cone defined in JIS R5201)
(2) Flow table (Flow table with a diameter of 30 cm as defined in JIS R5201)
(3) Stick (metal stick specified in JIS R5201)

(Test method)
(1) The flow cone was placed on a flow table.
(2) The cement composition was packed in a flow cone in two portions. Each layer was struck 15 times with a stab, and finally the surface was leveled to compensate for the deficiency.
(3) Gently lift the cylinder in the vertical direction, and after 1 minute after the cement composition spreads, measure the diameter in the direction recognized as the maximum and the diameter in the direction perpendicular to it, and calculate the average value of these values as the natural flow value. It was.
(4) A falling motion was given 15 times in 15 seconds, the diameter after the cement composition spread was measured as the maximum, and the diameter in the direction perpendicular thereto was measured. The average value of these was determined as the tapping flow value. did.
(5) A value obtained by dividing the tapping flow value by the natural flow value was used as an index to obtain an index of thixotropy.

<Viscosity, thixotropic index>
The viscosity was measured using a BH type rotational viscometer, and the thixotropic index (TI value) was calculated.
(1) The kneaded cement composition was transferred to a beaker and allowed to stand for 1 minute.
(2) Using a BH type rotational viscometer, the viscosity was measured at a rotor rotational speed of 2 rpm.
(3) Viscosity was measured at a rotational speed of the rotor of 20 rpm using a BH type rotational viscometer.
(4) The TI value (viscosity at 2 rpm / viscosity at 20 rpm) was calculated.

<Thixotropic properties>
The determination was made with the index calculated by measuring the fluidity and the TI value calculated by measuring the viscosity.
(Evaluation)
○: The index is 1.4 or more and the TI value is 3.0 or more.
X: Index is less than 1.4 and TI value is less than 3.0.

<Sagging>
(1) A cylinder having an inner diameter of 5 cm and a height of 5 cm was placed on an inclined surface having a gradient of 100/1000.
(2) The sample was packed and the surface was leveled.
(3) The cylinder was gently pulled out in the vertical direction.
(4) The appearance of the sample was observed and evaluated.
(Evaluation)
○: The cylinder was pulled out and did not sag at all.
Δ: The cylinder was pulled out and the cylinder was slightly tilted.
X: The cylinder was pulled out and the columnar shape collapsed considerably.

<Breathing (conforming to JSCE-F 522-1999)>
Material separation resistance (breathing rate) of cement composition in accordance with the Japan Society of Civil Engineers standard "Testing method for bleeding rate and expansion rate of mortar of prepacked concrete (polyethylene bag method)" (JSCE-F 522-1999) And the expansion coefficient was measured.
(Tool)
(1) Polyethylene bag (with a cement composition in a diameter of about 50 mm, with a diameter of about 50 mm, polyethylene thickness of about 0.05 mm, bottom is square)
(2) Measuring cylinder (capacity 1000ml)

(Test method)
(1) A polyethylene bag was filled with a cement composition to a height of about 20 cm.
(2) A polyethylene bag filled with the cement composition was inserted into a graduated cylinder containing 400 ml of water so as not to be mixed with air gently.
(3) The polyethylene bag was lowered until the water surface in the graduated cylinder coincided with the surface of the cement composition, and 400 ml was subtracted from the reading of the graduated cylinder at this time to obtain the volume Vml of the cement composition.
(4) The upper end of the polyethylene bag was tied and hung and allowed to stand.
(5) When 24 hours or more have elapsed after the start of measurement, the water surface V1 ml by breathing and the surface V2 ml of cement composition are read in the same manner as (2) and (3), respectively, and the water amount by breathing is subtracted from the former from the former. Bml was determined. When there is no breathing water, V1 = V2.
(6) Breathing rate and expansion rate were calculated by the following formula.
B = V1-V2
Breathing rate (%) = B / V × 100
Expansion rate (%) = (V1−V) / V × 100

[Synthesis Example 1]
750 g of cyclohexane, Rhedol SP-S10V (sorbitan monostearate, HLB = 5, Kao Corp.) Prepared), a reflux cooling dehydration tube and a dropping funnel were provided, and stirring was started at a stirring speed of 700 rpm. Meanwhile, TBAS-Q (2-acrylamido-2-methylpropanesulfonic acid, manufactured by MRC Unitech Co., Ltd.) 207 g (32.5 mol%) was added to a 2 L disc, and hydroxy-tetramethyl-1 was cooled from the outside. -Non-neutralized 2-acrylamide-2 by dropping 410 g of an aqueous sodium hydroxide solution containing 0.02 g of piperidine oxyl and dissolving 24.0 g of sodium hydroxide to neutralize 60 mol% of TBAS-Q -An aqueous solution containing 40% of methylpropanesulfonic acid by molar ratio and 60% of neutralized 2-acrylamido-2-methylpropanesulfonic acid by molar ratio was prepared. After 142 g (67.3 mol%) of acrylamide, 0.5 g (0.2 mol%) of acrylic acid, 0.15 g of N, N′-methylenebisacrylamide and 0.5 g of ammonium persulfate were added to this solution and dissolved. Nitrogen gas was blown to expel dissolved oxygen.

  Next, the monomer aqueous solution containing the polymerization initiator and the crosslinking agent obtained as described above was added to the above-mentioned cyclohexane, 0.3 g of sodium hydrogen sulfite was added in a powder state, and then the temperature was increased to 70 ° C. Polymerization was started by raising the temperature. After the exotherm due to polymerization had subsided, 3.0 g of DK ester F-90 (sucrose stearate ester, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) was added. While stirring at a stirring speed of 700 rpm for 1 hour, the temperature in the system was controlled to a temperature of 60 ° C to 70 ° C. After 330 g of water was extracted by azeotropic dehydration, the resin was taken out and dried at 70 ° C. under reduced pressure to obtain polymer particles A.

[Synthesis Example 2]
750 g of cyclohexane, Rhedol SP-S10V (sorbitan monostearate, HLB = 5, Kao Corp.) Prepared), a reflux cooling dehydration tube and a dropping funnel were provided, and stirring was started at a stirring speed of 700 rpm. On the other hand, 213 g (65 mol%) of acrylamide, 116 g (35 mol%) of acrylic acid, 0.21 g of N, N′-methylenebisacrylamide, and 0.75 g of ammonium persulfate were added to a 2 L disc, and then dissolved. Gas was blown out to expel dissolved oxygen.
Next, the monomer aqueous solution containing the polymerization initiator and the crosslinking agent obtained as described above was added to the above-mentioned cyclohexane, 0.3 g of sodium hydrogen sulfite was added in a powder state, and then the temperature was increased to 70 ° C. Polymerization was started by raising the temperature. After the exotherm due to polymerization had subsided, 3.0 g of DK ester F-90 (sucrose stearate ester, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) was added. While stirring at a stirring speed of 700 rpm for 1 hour, the temperature in the system was controlled to a temperature of 60 ° C to 70 ° C. After 330 g of water was extracted by azeotropic dehydration, the resin was taken out and dried at 70 ° C. under reduced pressure to obtain polymer particles B.

[Synthesis Example 3]
750 g of cyclohexane, Rhedol SP-S10V (sorbitan monostearate, HLB = 5, Kao Corp.) Prepared), a reflux cooling dehydration tube and a dropping funnel were provided, and stirring was started at a stirring speed of 700 rpm. On the other hand, 207 g (40 mol%) of TBAS-Q (2-acrylamido-2-methylpropanesulfonic acid, manufactured by MRC Unitech Co., Ltd.) was added to a 2 L disc, and hydroxy-tetramethyl-1-piperidine was cooled from the outside. Non-neutralized 2-acrylamido-2-methyl is obtained by dropping 410 g of an aqueous sodium hydroxide solution containing 0.02 g of oxyl and dissolving 24.0 g of sodium hydroxide to neutralize 60 mol% of TBAS-Q. An aqueous solution containing 40% of propanesulfonic acid by molar ratio and 60% of neutralized 2-acrylamido-2-methylpropanesulfonic acid by molar ratio was prepared. To this solution, 108 g (60 mol%) of acrylic acid, 0.12 g of N, N′-methylenebisacrylamide and 0.4 g of ammonium persulfate were added and dissolved, and then nitrogen gas was blown to drive out dissolved oxygen.

  Next, the monomer aqueous solution containing the polymerization initiator and the crosslinking agent obtained as described above was added to the above-mentioned cyclohexane, 0.3 g of sodium hydrogen sulfite was added in a powder state, and then the temperature was increased to 70 ° C. Polymerization was started by raising the temperature. After the exotherm due to polymerization had subsided, 3.0 g of DK ester F-90 (sucrose stearate ester, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) was added. While stirring at a stirring speed of 700 rpm for 1 hour, the temperature in the system was controlled to a temperature of 60 ° C to 70 ° C. After 330 g of water was extracted by azeotropic dehydration, the resin was taken out and dried at 70 ° C. under reduced pressure to obtain polymer particles C.

[Synthesis Example 4]
A pressure reactor equipped with a stirrer was charged with 100 parts by weight of pulp and 50 parts by weight of dimethyl ether, and after the inside of the container was sufficiently purged with nitrogen, 230 parts by weight of 50% by weight aqueous sodium hydroxide solution was stirred at 90 ° C. or lower. Was added dropwise to prepare alkali cellulose. Next, the reaction solution was cooled to 40 ° C. or lower, charged with 150 parts by weight of chloromethyl and 45 parts by weight of propylene oxide, and reacted at 40 to 90 ° C. for 3 hours. The obtained reaction product was washed with hot water at 80 to 90 ° C. and then air-dried at 80 ° C. to obtain 125 parts by weight of colorless solid hydroxypropylmethylcellulose (HPMC).

  In the HPMC obtained as described above, the hydroxypropyl group substitution amount was MS = 0.25, and the methyl group substitution degree was DS = 1.9.

[Synthesis Example 5]
A pressure reactor equipped with a stirrer was charged with 100 parts by weight of pulp and 50 parts by weight of dimethyl ether, and after the inside of the container was sufficiently purged with nitrogen, 230 parts by weight of 50% by weight aqueous sodium hydroxide solution was stirred at 90 ° C. or lower. Was added dropwise to prepare alkali cellulose. Next, the reaction solution was cooled to 40 ° C. or less, charged with 85 parts by weight of chloroethyl and 275 parts by weight of ethylene oxide, and reacted at 40 to 90 ° C. for 3 hours. The obtained reaction product was washed with hot water at 80 to 90 ° C., and then air-dried at 80 ° C. to obtain 162 parts by weight of colorless solid hydroxyethyl ethyl cellulose (HEEC).
In the HEEC obtained as described above, the hydroxyethyl group substitution amount was MS = 2.0, and the ethyl group substitution degree was DS = 0.8.

[Example 1]
1620 parts of water was placed in a stirring vessel (KITCHEN AID KSM5), and 3600 parts of ordinary Portland cement (manufactured by Taiheiyo Cement Co., Ltd.) was added while stirring, and stirred for 2 minutes. Next, 180 parts of water, 10 parts of polymer particles A of Synthesis Example 1 and 5 parts of HPMC of Synthesis Example 4 were mixed in advance and stirred for 1 minute to obtain the cement composition of the present invention. The evaluation results of various properties of the obtained cement composition are shown in Table 1.

[Example 2]
A cement composition of the present invention was obtained in the same manner as in Example 1 except that HPMC in Synthesis Example 4 was replaced with HEEC in Synthesis Example 5. The evaluation results of various properties of the obtained cement composition are shown in Table 1.

[Example 3]
A cement composition of the present invention was obtained in the same manner as in Example 1 except that the polymer particle A in Synthesis Example 1 was replaced with the polymer particle B in Synthesis Example 2. The evaluation results of various properties of the obtained cement composition are shown in Table 1.

[Example 4]
A composition of the present invention was obtained in the same manner as in Example 1 except that the polymer particle A in Synthesis Example 1 was replaced with the polymer particle C in Synthesis Example 3. The evaluation results of various properties of the obtained cement composition are shown in Table 1.

[Example 5]
A cement composition of the present invention was obtained in the same manner as in Example 1 except that the amount of polymer particles A in Synthesis Example 1 was changed to 3.6 parts and the amount of HPMC in Synthesis Example 4 was changed to 3.6 parts. . The evaluation results of various properties of the obtained cement composition are shown in Table 1.

[Example 6]
A cement composition of the present invention was obtained in the same manner as in Example 1 except that the amount of HPMC in Synthesis Example 4 was changed to 1.8 parts. The evaluation results of various properties of the obtained cement composition are shown in Table 1.

[Example 7]
1944 parts of water was placed in a stirring container, and 3600 parts of ordinary Portland cement was added while stirring, followed by stirring for 2 minutes. Next, 216 parts of water, 12 parts of polymer particles A of Synthesis Example 1 and 6 parts of HPMC of Synthesis Example 4 were mixed in advance and stirred for 1 minute to obtain a cement composition of the present invention. The evaluation results of various properties of the obtained cement composition are shown in Table 1.

  As shown in Table 1, in Examples 1 to 7, a cement composition having high thixotropic properties, hardly causing breathing, and having a small volume shrinkage was obtained.

[Comparative Example 1]
A cement composition was obtained in the same manner as in Example 1 except that the polymer particles A in Synthesis Example 1 were replaced with a crosslinked acrylic acid homopolymer. The evaluation results of various properties of the obtained cement composition are shown in Table 2.

[Comparative Example 2]
A cement composition was obtained in the same manner as in Example 1 except that the polymer particles A of Synthesis Example 1 were not added. The evaluation results of various properties of the obtained cement composition are shown in Table 2.

[Comparative Example 3]
A cement composition was obtained in the same manner as in Example 1 except that HPMC in Synthesis Example 4 was replaced with methylcellulose. The evaluation results of various properties of the obtained cement composition are shown in Table 2.

[Comparative Example 4]
A cement composition was obtained in the same manner as in Example 1 except that HPMC of Synthesis Example 4 was not added. The evaluation results of various properties of the obtained cement composition are shown in Table 2.

[Comparative Example 5]
A cement composition was obtained in the same manner as in Example 1 except that the amount of HPMC in Synthesis Example 4 was changed to 18 parts. The evaluation results of various properties of the obtained cement composition are shown in Table 2.

[Comparative Example 6]
A cement composition was obtained in the same manner as in Example 1 except that the amount of HPMC in Synthesis Example 4 was changed to 0.9 part. The evaluation results of various properties of the obtained cement composition are shown in Table 2.

  As shown in Table 2, the cement compositions of Comparative Examples 1, 2, and 5 have low thixotropic properties and low properties of lowering fluidity after standing still, so that they drip after spraying or from the void after injection into the cavity. It was easy for deviations to occur. In addition, the cement compositions of Comparative Examples 2, 3, 4, and 6 have large breathing and volume shrinkage, and voids are formed after curing, so that the adhesion to the sprayed surface is reduced, or the voids are filled in the filled cavities. Due to the phenomenon such as generation, the strength as designed could not be expressed.

(Combination ratio of examples)
The blending ratios (weight ratios) of (a) to (d) in the cement compositions of the present invention of Examples 1 to 7 are as shown below.
Example 1:
Cement (a) / water (b) = 100/50, polymer particle A (c) / water (b) = 1/180 of synthesis example 1, HPMC (d) / water (b) = 1 of synthesis example 4 / 360, polymer particles A (c) of Synthesis Example 1 / HPMC (d) of Synthesis Example 4 = 2/1

Example 2:
Cement (a) / water (b) = 100/50, polymer particle A (c) / water (b) = 1/180 of synthesis example 1, HEEC (d) / water (b) = 1 of synthesis example 5 / 360, polymer particles A of synthesis example 1 (c) / HEEC of synthesis example 5 (d) = 2/1

Example 3:
Cement (a) / Water (b) = 100/50, Polymer Particle B (c) / Water (b) = 1/180 of Synthesis Example 2, HPMC (d) / Water (b) = 1 of Synthesis Example 4 / 360, polymer particles B (c) of Synthesis Example 2 / HPMC (d) of Synthesis Example 4 = 2/1

Example 4:
Cement (a) / water (b) = 100/50, polymer particles C of synthesis example 3 (c) / water (b) = 1/180, HPMC of synthesis example 4 (d) / water (b) = 1 / 360, polymer particles C (c) of Synthesis Example 3 / HPMC (d) of Synthesis Example 4 = 2/1

Example 5:
Cement (a) / water (b) = 100/50, polymer particles A (c) of synthesis example 1 / water (b) = 1/500, HPMC (d) of synthesis example 4 / water (b) = 1 / 500, polymer particles A (c) of Synthesis Example 1 / HPMC (d) of Synthesis Example 4 = 1/1

Example 6:
Cement (a) / water (b) = 100/50, polymer particle A (c) / water (b) = 1/180 of synthesis example 1, HPMC (d) / water (b) = 1 of synthesis example 4 / 1000, polymer particles A of synthesis example 1 (c) / HPMC of synthesis example 4 (d) = 6/1

Example 7:
Cement (a) / water (b) = 100/60, polymer particle A (c) / water (b) = 1/180 of synthesis example 1, HPMC (d) / water (b) = 1 of synthesis example 4 / 360, polymer particles A (c) of Synthesis Example 1 / HPMC (d) of Synthesis Example 4 = 2/1

(Compounding components of comparative examples and their blending ratios and characteristics)
The relationship between the blending components in the cement compositions of Comparative Examples 1 to 6 and the blending ratio (weight ratio) and various properties is as follows.
Comparative Example 1:
Cement (a) / water (b) = 100/50, HPMC (d) / water (b) = 1/360 of Synthesis Example 4, but acrylic acid homopolymer instead of the crosslinked acrylic polymer particles (c) Because it uses a polymer cross-linked product, its thixotropic property is low. The liquidity has improved.

Comparative Example 2:
Cement (a) / water (b) = 100/50, HPMC (d) / water (b) = 1/360 of Synthesis Example 4, but no crosslinked acrylic polymer particles are added, so that no bleeding Inferior in properties and low in thixotropy.

Comparative Example 3:
Cement (a) / water (b) = 100/50, polymer particle A (c) / water (b) = 1/180 of synthesis example 1, but hydroxyalkyl-modified cellulose resin, hydroxyalkylalkyl-modified cellulose resin Since other cellulose resins (methylcellulose) are used, the breathing resistance is inferior.

Comparative Example 4:
Cement (a) / water (b) = 100/50, polymer particle A (c) / water (b) = 1/180 of synthesis example 1, but no thixotropic property because there is no addition of cellulosic resin There is, however, inferior breathing resistance.

Comparative Example 5:
Cement (a) / water (b) = 100/50, polymer particle A (c) / water (b) = 1/180 of synthesis example 1, HPMC (d) / water (b) = 1 of synthesis example 4 / 100, but since the cellulose resin (d) is more than the crosslinked acrylic polymer particles (c), the polymer particles A (c) in Synthesis Example 1 / HPMC (d) in Synthesis Example 4 = It is 0.6 / 1 and the thixotropic property is lowered.

Comparative Example 6:
Cement (a) / water (b) = 100/50, polymer particles A (c) of synthesis example 1 / water (b) = 1/180, but added amount of crosslinked acrylic polymer particles (c) On the other hand, the amount of cellulose resin (d) added is small, HPMC (d) in Synthesis Example 4 / water (b) = 1/2000, Polymer Particle A (c) in Synthesis Example 1 / Synthesis Example 4 Since HPMC (d) = 11/1, the breathing resistance is lowered.

The present invention is suitable for spraying materials, grout materials and the like used in the civil engineering and construction fields.

Claims (6)

  A cement composition comprising cement (a) and water (b) contains crosslinked acrylic polymer particles (c) and alkyl ether-modified cellulose resin (d), and the content ratio is cement (a) / water. (B) = 100/40 to 100/100 (weight ratio), crosslinked acrylic polymer particles (c) / water (b) = 1/500 to 1/100 (weight ratio), alkyl ether modified Cellulose resin (d) / water (b) = 1/1000 to 1/100 (weight ratio), crosslinked acrylic polymer particles (c) / alkyl ether-modified cellulose resin (d) = 1/1 to 10 / 1 (weight ratio), the crosslinked acrylic polymer particles (c) are water-insoluble powders composed of crosslinked acrylic polymer particles containing sulfonic acid groups and / or acrylamide groups. To Cement composition.   The crosslinked acrylic polymer particles (c) / water (b) are 1/350 to 1/150 (weight ratio), and the crosslinked acrylic polymer particles (c) have a particle size of 0.1 to The cement composition according to claim 1, which is 50 µm. The cement composition according to claim 1 or 2, wherein the crosslinked acrylic polymer particle (c) is a polymerization reaction product having a compound represented by the following general formula (1) as a monomer.

(In the formula, R ¹ represents a hydrogen atom or a methyl group, R ² represents a linear or branched alkylene group having 2 to 4 carbon atoms, and X represents a hydrogen atom, an alkali metal, an alkaline earth metal, or Indicates an ammonium group.) The cement composition according to claim 1 or 2, wherein the crosslinked acrylic polymer particle (c) is a polymerization reaction product having a compound represented by the following general formula (2) as a monomer.

(In the formula, R ¹ represents a hydrogen atom or a methyl group.) The cement composition according to any one of claims 1 to 4, wherein the alkyl ether-modified cellulose resin (d) includes a structure represented by the following general formula (3).

(Wherein R ¹ , R ² and R ³ are hydrogen atoms, or the formula C _n H _2n OH, C _m H _{2m + 1} , (C _n H _2n O) ₁ C _n H _2n OH or (C _n H _2n O ) ₁ C _m H _{2m + 1} is represented, l represents an integer of 1 to 10, m and n represent an integer of 1 to 5. Any one of R ¹ , R ² and R ³ is , Not a hydrogen atom or C _m H _{2m + 1} , they may be the same or different.) In the alkyl ether-modified cellulose resin (d), the average substitution amount of hydroxyalkyl groups per glucose unit of cellulose is 0.1 to 4.0, and the average substitution degree of alkyl groups per glucose unit of cellulose is 2 The cement composition according to any one of claims 1 to 4, which is 0.5 or less.