Grouting chemical composition for stabilizing soil property

Abstract

To provide a grouting chemical composition for stabilizing soil property which has reduced odor during grouting, can suppress scorch in a foam after a chemical is grouted and filled even under environment with a high liquid temperature, secures excellent ground reinforcement property by high strength, is excellent in storage stability and is usable without depending on storage environment.SOLUTION: A grouting chemical composition for stabilizing soil property is composed of a polyol component (A) and a polyisocyanate component (B), wherein the polyol component (A) contains polyether polyol (A-1), a nurating catalyst (A-2), a tertiary amine catalyst (A-3), and a diluent (A-4), the polyether polyol (A-1) has a number average molecular weight of 250 or more and 400 or less and an average number of functional groups of 2.5 or less, the nurating catalyst (A-2) is a quaternary ammonium salt in which anion is a carboxylic acid ion having 8 or more carbon atoms or an alkylcarbonic acid ion, and cation is an ammonium ion having an alkyl group having 5 or more carbon atoms, or a carboxylic acid metal salt in which anion is a carboxylic acid ion having 8 or more carbon atoms cation is a metal ion, the diluent (A-4) is either an alkyl ether-based diluent or a fatty acid ether-based diluent, the polyisocyanate component (B) is any one of a mixture of diphenylmethane diisocyanate and polyphenylpolymethylene polyisocyanate, and NCO INDEX when the polyol component (A) and the polyisocyanate component (B) are mixed is within the range of 230 to 350.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a soil stabilization grout composition. [Background technology]

[0002] Traditionally, mortar, expansive-agent-mixed mortar, bentonite mortar, and other soil stabilization injection materials have been used to fill voids between the foundations of tunnels, underground structures, and high-rise buildings and the surrounding bedrock or ground, or to fill voids within the bedrock or ground. These materials are also used as ground injection materials to reinforce and improve weak ground by infiltrating them. However, these materials are bulky and require extensive equipment, which makes them difficult to work in small spaces. Furthermore, when injected into voids in aging structures, their high specific gravity places a heavy burden on the structure. Furthermore, when water is present in the voids, the filler's effectiveness is delayed, requiring long construction times. Furthermore, filling the voids makes it difficult to prevent groundwater runoff, resulting in poor watertightness. Therefore, the use of urethane-based void fillers has been proposed and implemented in recent years as a solution to these problems.

[0003] For example, Patent Document 1 reports that by using a polyol whose main component is a polyol with an average functionality of 3, mixing it with an NCO index in the range of 120 to 200, and injecting it into voids, it is possible to reduce weight and improve workability compared to mortar-based fillers. However, because the polyol component uses a polyol with a high functionality as its main component, there is a concern that the crosslinking component increases, preventing sufficient reaction, and reducing the compressive strength of the foam. Furthermore, reaction heat tends to accumulate inside the foam, and if the liquid temperature rises due to seasonal factors, there is a concern that scorching (burning) may occur.

[0004] Patent Document 2 discloses a void-filling injection composition that uses triethylmethylammonium octylate as a nurate catalyst, but there is a demand for compositions with even better storage stability. In particular, a liquid composition that shows little effect on the reaction rate, etc., even after long-term storage at room temperature to 50°C has the advantage of being less susceptible to storage conditions such as seasonal variations and can be used flexibly throughout the year. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-15881 [Patent Document 2] Patent Publication No. 2021-98819 Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention has been made in view of the above-mentioned background art, and aims to provide a soil stabilization grouting composition that has a low odor when injected, can suppress scorching inside the foam after the chemical solution is injected and filled even in an environment with a high liquid temperature, and further has high strength to ensure excellent ground reinforcement properties, and has excellent storage stability so that it can be used regardless of the storage environment. [Means for solving the problem]

[0007] As a result of extensive research, the present inventors have discovered that the above-mentioned problems can be solved by a soil stabilization grout composition comprising a polyol component (A) containing a specific component as a diluent and a polyisocyanate component (B), and have thus completed the present invention.

[0008] That is, the present invention includes the following embodiments [1] to [3]. [1] A soil stabilization grout composition comprising a polyol component (A) and a polyisocyanate component (B), The polyol component (A) comprises a polyether polyol (A-1), a nuration catalyst (A-2), a tertiary amine catalyst (A-3), and a diluent (A-4); The polyether polyol (A-1) has a number average molecular weight of 250 or more and 400 or less and an average functionality of 2.5 or less; the nuration catalyst (A-2) is either a quaternary ammonium salt whose anion is a carboxylate ion or alkylcarbonate ion having 8 or more carbon atoms and whose cation is an ammonium ion having an alkyl group having 5 or more carbon atoms, or a carboxylate metal salt whose anion is a carboxylate ion having 8 or more carbon atoms and whose cation is a metal ion; The diluent (A-4) is either an alkyl ether diluent or a fatty acid ester diluent, The polyisocyanate component (B) is either a mixture of diphenylmethane diisocyanate and polyphenylpolymethylene polyisocyanate or a reaction product of the mixture with a polyol; A soil stabilization grout composition having an NCO index in the range of 230 to 350 when the polyol component (A) and the polyisocyanate component (B) are mixed. [2] The soil stabilization grout composition according to the above [1], wherein the polyol component (A) further contains a silicone foam stabilizer. [3] A foam obtained from the soil stabilization grout composition according to [1] or [2] above.

[0009] In this specification, a numerical range indicated using "to" indicates a range that includes the numerical values ​​before and after "to" as the minimum and maximum values, respectively. [Effects of the Invention]

[0010] The soil stabilization grouting composition of the present invention has a low odor during injection, can suppress scorching inside the foam after the chemical solution is injected and filled even in environments with high liquid temperatures, and has high strength, which not only ensures excellent ground reinforcement, but also allows for the provision of a soil stabilization grouting composition that can be used at any time, regardless of the storage environment. DETAILED DESCRIPTION OF THE INVENTION

[0011] The present invention will now be described in further detail.

[0012] The soil stabilization grout composition of the present invention comprises a polyol component (A) and a polyisocyanate component (B).

[0013] First, the polyol component (A) will be described.

[0014] The polyol component (A) (hereinafter also referred to simply as component (A)) contains a polyether polyol (A-1) (hereinafter also referred to simply as (A-1)), a nurate catalyst (A-2) (hereinafter also referred to simply as (A-2)), a tertiary amine catalyst (A-3) (hereinafter also referred to simply as (A-3)), and a diluent (A-4) (hereinafter also referred to simply as (A-4)).

[0015] The polyether polyol (A-1) has a number average molecular weight of 250 or more and 400 or less, and an average number of functional groups of 2.5 or less.

[0016] Examples of (A-1) include polyethylene glycol, polypropylene glycol, polyoxyethylene polyoxypropylene glycol, polytetramethylene glycol, etc. As long as the above-mentioned number average molecular weight and average functionality are satisfied, either one type of polyether polyol or a composition containing two or more types of polyether polyols may be used, and when two or more types are used, those with different numbers of functional groups may be used, and it is preferable to include at least one type of polyether polyol, both those with two functional groups and those with three functional groups.

[0017] The number-average molecular weight of (A-1) is 250 or more and 400 or less, and preferably 300 or more and 400 or less. If it is less than 250, the number of active hydrogen groups will be too high, which may result in significant heat generation due to the reaction during injection and the risk of scorching. If it exceeds 400, physical properties such as compressive strength will decrease, which may impair the ground reinforcing effect. When two or more types are used in combination, the number-average molecular weight is treated as the number-average molecular weight after mixing with the polyether polyols used. When two or more types are used in combination, each individual polyether polyol preferably has a number-average molecular weight of 180 or more and 1200 or less, and it is preferable to include at least one type of polyether polyol with a number-average molecular weight of 180 or more and 450 or less and one with a number-average molecular weight of 800 or more and 1200 or less.

[0018] The average functionality of (A-1) is 2.5 or less, preferably in the range of 2.0 to 2.5. If it exceeds 2.5, the crosslinking component becomes too much and the reaction does not proceed sufficiently, which may result in a decrease in the compressive strength of the foam. If it is below 2.0, there is a risk of cell collapse and a decrease in strength. When two or more types are used in combination, the average functionality is treated as the average functionality after mixing with the polyether polyols used.

[0019] The nurate catalyst (A-2) is either a quaternary ammonium salt whose anion is a carboxylate ion or alkylcarbonate ion having 8 or more carbon atoms and whose cation is an ammonium ion having an alkyl group having 5 or more carbon atoms, or a metal carboxylate whose anion is a carboxylate ion having 8 or more carbon atoms and whose cation is a metal ion. Examples of (A-2) include quaternary ammonium salts and metal carboxylates.

[0020] When a quaternary ammonium salt is used, examples of the cation portion of the quaternary ammonium salt include diethyldimethylammonium, triethylmethylammonium, tetraethylammonium, tetrapropylammonium, tripropylethylammonium, tetrabutylammonium, tetrapentylammonium, tetrahexylammonium, tetraoctylammonium, octyltrimethylammonium, tridecyltrimethylammonium, stearyltrimethylammonium, etc. These can be used alone or in combination of two or more.

[0021] Examples of the anion moiety include alkyl carbonates and carboxylates. Examples of carboxylic acids include acetic acid, butanoic acid, pentanoic acid, hexanoic acid, octylic acid, nonanoic acid, decanoic acid, undecanoic acid, dodecanoic acid, tridecanoic acid, tetradecanoic acid, pentadecanoic acid, hexadecanoic acid, heptadecanoic acid, and stearyl acid. Among these, octylic acid is preferred from the viewpoints of odor, reactivity, and supply stability.

[0022] When a metal carboxylate is used, examples of the metal include sodium, potassium, calcium, tin, bismuth, zinc, zirconium, etc. Examples of the carboxylic acid include the above-mentioned carboxylic acids.

[0023] The content of (A-2) in the present invention is preferably 0.1 to 5% by mass in component (A). If it is less than 0.1% by mass, there is a risk of deterioration in curability and foaming properties, while if it exceeds 5% by mass, it becomes difficult to control the reaction and there is a risk of poor injection due to clogging of the resin during chemical injection.

[0024] Examples of (A-3) include N,N,N',N'-tetramethylhexamethylenediamine, N,N,N',N'-tetramethylpropylenediamine, N,N,N',N',N"-pentamethyldiethylenetriamine, N,N',N'-trimethylaminoethylpiperazine, N,N,N',N'-tetramethylethylenediamine, bis-(dimethylaminoethyl)ether, N,N',N'-tris(3-dimethylaminopropyl)hexahydro-S-triazine, 2-methyltriethylenediamine, N,N-dimethylaminoethylmorpholine, dimethylaminopropylimidazole, hexamethyltriethylenetetramine, hexamethyltripropylenetetramine, N,N,N-tris(3-dimethylaminopropyl)amine, N-methyl-N,N-bis(3-dimethylaminopropyl)amine, triethylenediamine, N-methylmorpholine, N-methylimidazole, and N,N-dimethylethanol. Amines, N-methyl-N-(N',N'-dimethylaminoethyl)aminoethanol, N,N-dimethylethoxyethanol, 1,4-diazabicyclo[2.2.2]octane-2-methanol, 6-dimethylamino-1-hexanol, N',N-dimethylethoxy-N'-methyl-N'-ethylmethanol, N'',N''-dimethylamino-N'-methylethylamino-N-methyl-2-propanol, bis(2-dimethylaminoethylamino) )-2-propanol, N'-[2-(dimethylamino)ethyl]-N,N-dimethylethylenediamine, 3,3-iminobis(N,N-dimethyl-1-propanamine), N'-[2-(dimethylamino)methyl]-N,N-dimethylmethylenediamine, N,N,N',N'-tetraethyldiethylenetriamine, 2-[2-(dimethylamino)ethoxy]-N-[2-[2-(dimethylamino)ethoxy]ethyl]-ethanamine, and the like.

[0025] Among these, triethylenediamine or bis-(dimethylaminoethyl) ether is preferred from the viewpoint of reactivity, and it is more preferred to use these in combination.

[0026] The content of (A-3) in the present invention is preferably 0.1 to 5% by mass in component (A). If it is less than 0.1% by mass, there is a risk of deterioration in curability and foaming properties, while if it exceeds 5% by mass, it becomes difficult to control the reactivity, and there is a risk of poor injection due to clogging of the resin during chemical injection.

[0027] In the present invention, a foam stabilizer may be used in component (A) to stabilize the cell size during foaming, and examples of the foam stabilizer include silicone-based foam stabilizers, such as polyoxyalkylenedimethylpolysiloxane copolymers and organopolysiloxanes.

[0028] When a foam stabilizer is used in the present invention, its content in component (A) is preferably 3% by mass or less, since if it exceeds 3% by mass, the resin strength may decrease.

[0029] In the present invention, a flame retardant may be used in component (A) in consideration of safety and the working environment. Examples of the flame retardant include phosphorus-based flame retardants. Examples of the phosphorus-based flame retardant include trimethyl phosphate, triethyl phosphate, tripropyl phosphate, triphenyl phosphate, trischloropropyl phosphate, tricresyl phosphate, trixylenyl phosphate, and tris(tribromoneopentyl)phosphate.

[0030] When a flame retardant is used in the present invention, its content in component (A) is usually 3 to 10% by mass.

[0031] The diluent (A-4) is either an alkyl ether diluent or a fatty acid ester diluent, and these may be used in combination as required.

[0032] When a diluent is used in the present invention, its content in component (A) is preferably 10% by mass or less. If it exceeds 10% by mass, the resin strength may decrease. Usually, the diluent content is 3% by mass or more.

[0033] Examples of the blowing agent in the present invention include water, hydrocarbons, hydrofluorocarbons, and hydrofluoroolefins. Among these, water is preferred from the viewpoint of storage stability and workability. If necessary, the above blowing agents may be used in combination.

[0034] When a blowing agent is used in the present invention, its content in component (A) is usually 0.1 to 5% by mass.

[0035] Next, the polyisocyanate component (B) will be described.

[0036] The polyisocyanate component (B) is either a mixture (B-1) (hereinafter also referred to as (B-1)) of diphenylmethane diisocyanate (hereinafter referred to as MDI) and polyphenylpolymethylene polyisocyanate (hereinafter referred to as polymeric MDI), or a reaction product of the mixture with a polyol.

[0037] In the present invention, MDI includes various isomers of 4,4'-MDI, 2,4'-MDI, and 2,2'-MDI, and polymeric MDI means MDI to which one or more phenyl groups having an isocyanate group are added via methylene groups.

[0038] The mass ratio of MDI to polymeric MDI in (B-1) is preferably MDI / polymeric MDI=20 / 80 to 80 / 20, more preferably 30 / 70 to 70 / 30.

[0039] Further, reaction products obtained by reacting a part of the isocyanate groups with active hydrogen groups such as alcohols and amines to modify them into urethane, allophanate, biuret, carbodiimide, isocyanurate, uretdione, etc. may also be used.

[0040] In the case of urethane modification, the prepolymer is preferably an isocyanate group-terminated prepolymer obtained by reacting a mixture of MDI and polymeric MDI with a polyol by a known method so that the equivalent ratio of isocyanate groups (hereinafter referred to as NCO groups) to OH groups (NCO groups / OH groups) is preferably in the range of 2 to 300, more preferably 5 to 100. Examples of the polyol include organic diols such as butanediol, polyols such as glycerin, trimethylolpropane, sorbitol, and sucrose, and polyether polyols obtained by adding alkylene oxides such as ethylene oxide, propylene oxide, and butylene oxide to monoethanolamine, diethanolamine, and triethanolamine or to these or ethylenediamine.

[0041] The viscosity of component (B) is preferably 300 mPa·s or less at 25° C., more preferably 50 to 250 mPa·s, in order to improve the injectability and penetration into voids.

[0042] In the soil stabilization grout composition of the present invention, the NCO index when the polyol component (A) and the polyisocyanate component (B) are mixed is in the range of 230 to 350, more preferably in the range of 230 to 330, and even more preferably in the range of 250 to 330. If the NCO index is less than 230, the strength of the foam will decrease and the reaction heat generated during injection will increase, causing scorching inside the foam, while if it exceeds 350, the curing properties of the foam will decrease.

[0043] The NCO index is the ratio of the number of moles of isocyanate groups in component (B) to the number of moles of hydroxyl groups in component (A) multiplied by 100, and is expressed as ((number of moles of isocyanate groups in component (B)) / (number of moles of hydroxyl groups in component (A))) × 100. The number of moles of hydroxyl groups here includes any substance that reacts with isocyanate groups in addition to the polyol contained in polyol component (A). For example, if the composition contains water, the calculation should also take into account the hydroxyl groups resulting from the water.

[0044] In the soil stabilization grout composition of the present invention, the blending amounts of the polyol component (A) and the polyisocyanate component (B) are preferably 15 to 35 mass% of the component (A) when the total of the components (A) and (B) is 100 mass%.

[0045] The soil stabilization grout composition of the present invention can contain the above-mentioned foam stabilizer, flame retardant, and diluent in a state where component (A) and component (B) are mixed together. Therefore, these agents may be contained in advance in either component (A) or component (B).

[0046] The soil stabilization grout composition is a compound that reacts with components (A) and (B) to produce a foam. The foam penetrates voids in liquid form and foams, filling the voids. In addition to its use as a void-filling grout composition, the composition can also be used as a reinforcing material or consolidating material for improving unstable ground such as ground or bedrock, as a reinforcing or repair material for structures such as concrete, and as a fixing material for anchors driven into the ground. [Example]

[0047] Examples of the present invention will be described in detail below, but the present invention is not limited to these examples. Unless otherwise specified, "%" in the examples is based on mass.

[0048] <Preparation of Polyol Component> The polyol components were prepared by mixing the raw materials shown in Table 1 for the examples and in Table 2 for the comparative examples. The number average molecular weights of the polyols in the polyol components shown in each table are values ​​when PPG-1 to PPG-4 were mixed in the respective ratios.

[0049] Examples 1 to 4

[0050] [Table 1]

[0051] (Comparative Examples 1 and 2)

[0052] [Table 2]

[0053] The raw materials in Tables 1 and 2 are as follows: PPG-1: Polypropylene glycol, molecular weight 300, functional group number 3 (product name: Adeka Polyether G-300, manufactured by ADEKA Corporation) PPG-2: Polypropylene glycol, molecular weight 200, functional group 2 (product name: Sannix PP-200, manufactured by Sanyo Chemical Industries, Ltd.) PPG-3: Polypropylene glycol, molecular weight 400, functional group number 2 (product name: Sannix PP-400, manufactured by Sanyo Chemical Industries, Ltd.) PPG-4: Polypropylene glycol, molecular weight 1000, functional group number 2 (trade name: Sannix PP-1000, manufactured by Sanyo Chemical Industries, Ltd.) Catalyst 1: Triethylenediamine (product name: TEDA-L33, manufactured by Tosoh Corporation) Catalyst 2: bis(2-dimethylaminoethyl) ether (trade name: TOYOCAT ET, manufactured by Tosoh Corporation) Catalyst 3: Triethylmethylammonium octylate (trade name: U-CAT18X, manufactured by San-Apro Co., Ltd.) Catalyst 4: Potassium octylate (trade name: DABCO K15, manufactured by EVONIK) Foam stabilizer: Silicone foam stabilizer (product name: TEGOSTAB B8404, manufactured by EVONIK) Flame retardant: Tris(2-chloropropyl)phosphate (trade name: TMCPP, manufactured by Daihachi Chemical Co., Ltd.) Diluent 1: Polyethylene glycol dimethyl ether (trade name: Hisorb MPM, manufactured by Toho Chemical Industry Co., Ltd.) Foaming agent: Water The following two types were used as the isocyanate component (B): Polyisocyanate (B1): A mixture of MDI and polymeric MDI (product name: MR-200, manufactured by Tosoh Corporation, isocyanate content: 30.1%, viscosity: 200 mPa·s at 25°C) Polyisocyanate (B2): Prepared according to the following preparation example.

[0054] <Preparation Example> 500 g of polyisocyanate (trade name: MR-200, manufactured by Tosoh Corporation), 450 g of diisocyanate (trade name: Millionate NM, manufactured by Tosoh Corporation), and 50 g of polyol (PO / EO polyether polyol, number average molecular weight 400, EO content 75%) were charged and heated to 80°C. The mixture was stirred uniformly with a stirring blade while maintaining the temperature and allowed to undergo a urethane reaction for 3 hours. After cooling, polyisocyanate B2 (NCO content 29.3%, viscosity at 25°C 110 mPa s) was obtained.

[0055] <Evaluation method> A foaming test was carried out using the polyol component (A) and polyisocyanate component (B) in the formulation shown in Table 1 (liquid temperature: 20°C, stirring conditions: mixed in a 1 L cup, stirred at 6000 rpm for 10 seconds using a homomixer, and the reactivity was measured in the cup). The results are shown in Table 1.

[0056] Cream time (CT): This refers to the time (seconds) from the start of mixing and stirring the polyol component (A) and the polyisocyanate component (B) until the mixture becomes cloudy and creamy and the liquid surface rises. Rise time (RT): This refers to the time (seconds) from the start of mixing and stirring the polyol component (A) and the polyisocyanate component (B) until the mixture foams and reaches its maximum height.

[0057] Foaming ratio: Calculate the foaming ratio during free foaming using the following formula: Expansion ratio (times) = volume of molded product after foaming (cm3) / volume of compound liquid before foaming (cm3) (formula) A foaming ratio of about 10 times is said to be good in terms of void filling properties and compressive strength.

[0058] Compression strength: Measured in accordance with JIS K 7220 (compression test method for rigid foam plastics), if the unconfined compressive strength is 1.50 MPa or more when the foaming ratio is 10 times, it can be said that the strength is sufficient for use as a soil stabilization injection material.

[0059] Maximum internal heat generation temperature: This refers to the maximum temperature (°C) inside the foam when the polyol component (A) and polyisocyanate component (B) are mixed and stirred at a liquid temperature of 20°C and foamed. If the heat generation temperature is less than 180°C, scorching can be suppressed even in the high liquid temperature range of around 40°C in summer, and this can be considered good.

[0060] Odor during foaming: The polyol component (A) and the polyisocyanate component (B) were mixed and stirred, and the odor generated when the blended liquid foamed was evaluated by sensory evaluation. If no amine or acid odor was detected, the rating was A, and if a significant amine or acid odor was detected, the rating was C. A rating of A indicates that the odor is good.

[0061] Skin layer cure: 10 minutes after the rise time was reached, an evaluation was conducted to see if any tack remained on the side of the foam facing the 1L cup used for foaming. A tack-free state was rated A, a state with slight tack remaining was rated B, and a state with tack or droplets remaining was rated C. A rating of A or B can be said to have been good curing during injection.

[0062] Storage stability: The prepared polyol was stored at 25°C and 50°C, and after standing, a foaming reaction was carried out. A delay rate of less than 50% of the rise time before storage was considered acceptable, and a delay rate of more than 50% was considered unacceptable.

Claims

1. A soil stabilization grout composition comprising a polyol component (A) and a polyisocyanate component (B), the polyol component (A) comprises a polyether polyol (A-1), a nurate catalyst (A-2), a tertiary amine catalyst (A-3), and a diluent (A-4), and the number average molecular weight of the polyether polyol (A-1) is 250 or more and 400 or less and the average number of functional groups is 2.5 or less; the nurate catalyst (A-2) is a quaternary ammonium salt whose anion is a carboxylate ion or alkylcarbonate ion having 8 or more carbon atoms and whose cation is an ammonium ion having an alkyl group having 5 or more carbon atoms, or a metal carboxylate salt whose anion is a carboxylate ion having 8 or more carbon atoms and whose cation is a metal ion; The diluent (A-4) is either an alkyl ether diluent or a fatty acid ester diluent, The polyisocyanate component (B) is any one of a reaction product of a mixture of diphenylmethane diisocyanate and polyphenylpolymethylene polyisocyanate with a polyol, A soil stabilization grout composition having an NCO INDEX in the range of 230 to 350 when the polyol component (A) and the polyisocyanate component (B) are mixed.

2. 2. The soil stabilization grout composition according to claim 1, wherein the polyol component (A) further contains a silicone foam stabilizer.

3. A foam obtained from the soil stabilization grout composition according to claim 1 or 2.

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