JP7698522B2 - Ground grouting liquid composition - Google Patents

Description

The present invention relates to a liquid chemical composition for ground injection, and in particular to a technology for improving the high-temperature foaming characteristics of a two-liquid liquid chemical composition for ground injection consisting of liquid A containing an aqueous silicate solution and a catalyst as essential components, and liquid B containing a polyisocyanate as an essential component.

A method of injecting inorganic or organic grout to consolidate the natural ground has been known for use in ground improvement applications for stabilizing and strengthening unstable rock or ground, and for filling cracks and voids in man-made structures. For example, a method has been adopted in which a foamable polyurethane material made by combining polyol and polyisocyanate is injected and allowed to foam and harden.

However, in the solidification method by injecting such foamable polyurethane material, a foamed hardened material mainly made of organic matter (resin) is produced by the urethane reaction between polyol and polyisocyanate, so there are inherent problems such as the risk of fire due to open flames, and because the material itself is expensive, there are also inherent problems such as soaring construction costs.

For this reason, Japanese Patent Application Laid-Open Nos. 5-78667 and 2004-075754 propose injection liquids consisting of Liquid A, whose main component is an aqueous alkali silicate solution, which is less expensive than conventional polyol-based organic materials, and Liquid B, whose main component is polyisocyanate. It is made clear that by injecting these two liquids and foaming and hardening them, a composite foamed and hardened body of inorganic and organic materials is formed, which can exhibit higher flame retardancy than conventional foamable polyurethane materials.

However, in the case of injection solutions consisting of liquid A and liquid B, the liquid may reach high temperatures of 30 to 40°C during construction in the summer depending on the outside air temperature, which may have a significant impact on the consolidation work of the ground. In other words, when an alkali silicate aqueous solution (water glass) reacts with a polyisocyanate at high temperatures, the reaction between water and polyisocyanate is accelerated, and foaming begins in a state in which the strength of the reaction product (foam) formed by the foaming and hardening caused by the reaction of liquid A and liquid B is not fully developed. Then, before the hardening of the reaction product occurs, the cells break or are broken, and as a result, at the end of the foaming stage, the obtained foamed hardened body has insufficient strength, and problems such as shrinking under its own weight or the strength of the foamed hardened body decreasing due to the coarsening and unevenness of the foam cells are caused.

Japanese Patent Application Publication No. 5-78667 JP 2004-075754 A

The present invention has been made against the background of the above-mentioned circumstances, and the problem to be solved is to provide a liquid composition for ground injection that can exhibit stable foaming properties even at high temperatures. Another problem is to provide a technology that can obtain a foam with excellent compressive strength while advantageously ensuring the strength of the foam formed by the reaction of a two-liquid liquid composition for ground injection consisting of liquid A containing an aqueous silicate solution and a catalyst as essential components, and liquid B containing a polyisocyanate as essential component.

The present invention can be suitably implemented in various aspects as listed below in order to solve the above problems, and each aspect described below can be adopted in any combination. It should be noted that the aspects and technical features of the present invention are not limited to those described below, but should be understood based on the inventive concept grasped from the entire description of the specification.

First, in order to solve the above-mentioned problems, the present invention provides, in its first aspect, a liquid composition for ground injection, which is composed of liquid A containing an aqueous silicate solution and a catalyst as essential components, and liquid B containing a polyisocyanate as an essential component, in which an aromatic polyisocyanate is used as the polyisocyanate, which is an essential component of liquid B, and in which liquid A contains a tertiary amine as the catalyst, and further contains a primary and/or secondary amino group-containing compound.

In addition, the second aspect of the present invention uses a polyamine compound having two or more primary and/or secondary amino groups in one molecule as the primary and/or secondary amino group-containing compound.

Furthermore, according to a third aspect of the present invention, the primary and/or secondary amino group-containing compound is characterized in that it has primary and/or secondary amino groups in a ratio of 0.5 to 50 mmol/g.

In addition, the fourth aspect of the present invention is characterized in that the primary and/or secondary amino group-containing compound is an aromatic amine compound.

The fifth aspect of the present invention is that the primary and/or secondary amino group-containing compound is contained in an amount of 0.01 to 20 parts by mass per 100 parts by mass of the polyisocyanate.

The sixth aspect of the present invention is characterized in that the tertiary amine as the catalyst has an alcoholic hydroxyl group.

The seventh aspect of the present invention is characterized in that the liquid A further contains a polyol.

In addition, the eighth aspect of the present invention is characterized in that each of the liquids A and B has a viscosity of 400 mPa·s or less at a temperature of 25°C.

In this way, in the liquid composition for ground injection according to the present invention, an aromatic polyisocyanate is used as the polyisocyanate, which is an essential component of Liquid B, and a tertiary amine is contained as the catalyst, which is an essential component of Liquid A. Furthermore, Liquid A contains a primary and/or secondary amino group-containing compound, so that the reaction between Liquid A and Liquid B can be effectively promoted, and foaming can be stably promoted in the early stages of the reaction even during construction at high temperatures in summer (30 to 40°C), thereby advantageously promoting crosslinking of the reaction product (foam), thereby increasing the stability of the properties such as strength of the reaction product, and uniforming the foam cells, effectively preventing shrinkage of the reaction product.

In particular, the composition of the liquid composition for ground injection according to the present invention makes it possible to advantageously ensure the strength of the reaction product produced during the reaction between liquid A and liquid B while foaming, thereby effectively increasing the stability of the properties such as the strength of the reaction product, including the strength during foaming, and also making the foam cells uniform, effectively suppressing shrinkage of the foam, particularly at high temperatures (30 to 40°C). In addition, by promoting crosslinking in the foam, it is possible to advantageously increase the compressive strength of the reaction product, which is a foam produced by the reaction.

In short, the present invention is a two-liquid type urethane liquid composition consisting of liquid A and liquid B, in which liquid A contains a tertiary amine as a catalyst in addition to the silicate aqueous solution as an essential component, and further contains a primary and/or secondary amino group-containing compound as a crosslinking agent in combination with the tertiary amine catalyst, and uses an aromatic polyisocyanate as the polyisocyanate as an essential component in liquid B, thereby effectively promoting the reaction between liquid A and liquid B and forming a reaction product (foam) more stably, and thus has a major feature in that it has been able to advantageously achieve the intended purpose.

The silicate aqueous solution contained as one of the essential components in the liquid A, which is one of the two liquids constituting the chemical liquid composition according to the present invention, is an aqueous solution of a soluble silicic acid compound, also called water glass. Examples of such silicic acid compounds include sodium silicate, potassium silicate, sodium metasilicate, potassium metasilicate, lithium silicate, and ammonium silicate. Among them, sodium silicate (sodium silicate), which is easy to obtain and inexpensive, is preferably used in the present invention. When sodium silicate is used, the molar ratio of SiO ₂ /Na ₂ O is preferably within the range of 2.0 to 4.0. If this molar ratio is less than 2.0, the compatibility with additives such as primary and/or secondary amino group-containing compounds and reaction catalysts is deteriorated, and gel-like substances are easily generated, making long-term storage difficult. On the other hand, if the molar ratio is greater than 4.0, the dispersion stability of the liquid decreases and the freezing point increases, which may cause problems such as making the liquid unusable in winter.

By the way, various kinds of water glass, which is an aqueous solution of sodium silicate as described above, are commercially available, and in the present invention, such commercially available products can be appropriately selected and used. Incidentally, aqueous solutions of sodium silicate are specified in the JIS standard (JIS K 1408) and are known as No. 1, No. 2, No. 3, etc., but as long as they are formulated in accordance with this JIS standard, it is also possible to use those with formulations such as No. 4, No. 5, No. 1.5, No. 2.5, etc. Furthermore, the proportion of solid components in the water glass in the form of such an aqueous solution varies depending on the JIS standard number and the type of water glass, but from the viewpoint of the stability and solidification characteristics of the A liquid, it is generally about 20 to 60 mass %, and preferably water glass containing 30 to 50 mass % of solid components is advantageously used.

In addition, a catalyst for promoting the reaction with liquid B is contained as an essential component in liquid A, and in the present invention, a tertiary amine catalyst is particularly advantageously used.

The tertiary amine catalyst may be a foaming catalyst that promotes the reaction between polyisocyanate and water when foaming is intended upon contact with water, a resinification catalyst that promotes the reaction between polyisocyanate and polyol, or an isocyanurate catalyst that promotes the trimerization of polyisocyanate. All of these are appropriately selected from known catalysts.

Specific examples of foaming catalysts include N,N,N',N",N"-pentamethyldiethylenetriamine (molecular weight: 173.3, boiling point: 198°C), N,N,N'-trimethylaminoethylethanolamine (molecular weight: 146.2, boiling point: 207°C), bis(dimethylaminoethyl)ether (molecular weight: 160.3, boiling point: 189°C), N,N,N'-trimethylaminoethylpiperazine (molecular weight: 171.3, boiling point: 96°C/12 mmHg), N,N-dimethylaminoethoxyethanol (molecular weight: 133.2, boiling point: 95°C/15 mmHg), and triethylamine (molecular weight: 101.2, boiling point: 89.3°C). The resinification catalyst includes N,N,N',N'-tetramethylethylenediamine (molecular weight: 116.2, boiling point: 120°C), N,N,N',N'-tetramethylpropanediamine (molecular weight: 130.2, boiling point: 145°C), N,N,N',N'-tetramethylhexamethylenediamine (molecular weight: 172.3, boiling point: 210°C), triethylenediamine (molecular weight: 112.2, boiling point: 174°C), 33% triethylenediamine/67% dipropylene glycol (molecular weight: 112.2, boiling point: 199°C), N, Examples of the solvent include N-dimethylaminohexanol (molecular weight: 145.3, boiling point: 117° C./12 mmHg), N,N-dimethylaminoethanol (molecular weight: 89.1, boiling point: 133° C.), N-methyl-N'-hydroxyethylpiperazine (molecular weight: 144.2, boiling point: 55° C./1.5 mmHg), N-methylmorpholine (molecular weight: 101.2, boiling point: 116° C.), 1-methylimidazole (molecular weight: 82.1, boiling point: 198° C.), and 1,2-dimethylimidazole (molecular weight: 96.1, boiling point: 205° C.). Further examples of isocyanurate catalysts include 2,4,6-tris(dimethylaminomethyl)phenol (molecular weight: 265.4, boiling point: 135°C/1 mmHg) and N,N',N"-tris(dimethylaminopropyl)-hexahydro-s-triazine (molecular weight: 342.6, boiling point: 141°C).

These catalysts may be used alone or in combination of two or more. Furthermore, among these, foaming catalysts or resinification catalysts are preferably used. In particular, among these tertiary amines, those having an alcoholic hydroxyl group are advantageously used in order to better achieve the object of the present invention. Furthermore, if the molecular weight of such a tertiary amine is low, it is prone to volatilization, and problems such as odor generation due to reaction heat during foaming and temperature in the construction environment are caused. Therefore, tertiary amines having a molecular weight of 104 or more, preferably 110 or more, are preferably used. Furthermore, in order to suppress the generation of odor caused by reaction heat during foaming, tertiary amines having a boiling point of 100°C or more at normal pressure are advantageously used.

The amount of tertiary amine as a catalyst contained in such liquid A is generally determined appropriately at a ratio of 0.05 to 5 parts by mass, preferably 0.1 to 3 parts by mass, per 100 parts by mass of polyisocyanate. If the content of tertiary amine as a catalyst is less than 0.05 parts by mass, there is a problem that the contribution to the reaction is reduced and the strength of the reaction product cannot be sufficiently ensured, while if it is more than 5 parts by mass, the reaction will proceed too far, causing an abnormal reaction, the liquid will solidify during the injection operation, and problems such as difficulty in achieving sufficient foaming will occur.

In addition to the above-mentioned tertiary amine, the A solution may contain a known metal catalyst or a quaternary ammonium salt catalyst as a catalyst, if necessary. Any known metal catalyst may be used without any particular restrictions as the metal catalyst, and for example, organic acid metal salts or organic metal complexes of sodium, potassium, calcium, tin, lead, bismuth, zinc, iron, nickel, zirconium, cobalt, etc. may be used. Among these, examples of organic acid metal salts include salts of the above metals with acetic acid, octylic acid, neodecanoic acid, naphthenic acid, rosin acid, etc., and examples of organic metal complexes include complexes of the above metals with acetylacetone, etc. Specifically, sodium acetate, potassium acetate, potassium octylate, bismuth octylate, lead octylate, iron octylate, tin octylate, calcium octylate, zinc octylate, zirconium octylate, bismuth neodecanoate, zinc neodecanoate, lead neodecanoate, cobalt neodecanoate, dibutyltin dioctate, dibutyltin dilaurate; iron acetylacetone, zinc acetylacetone, zirconium acetylacetone, nickel acetylacetone, tin acetylacetone, etc. may be mentioned. These metal salts and metal complexes may be used after being dissolved in a diluent such as mineral spirits, organic acids, glycols, esters, etc., in order to improve their handling properties. Moreover, these metal catalysts may be used alone or in combination of two or more kinds. Among these, preferred are acetates, octylates, neodecanoates, laurates, and acetylacetone complexes of potassium, tin, lead, bismuth, or zinc, and more preferably, catalysts using potassium, tin, or bismuth as the metal are preferably used.

Examples of quaternary ammonium salts include aliphatic ammonium compounds such as tetramethylammonium, methyltriethylammonium, ethyltrimethylammonium, propyltrimethylammonium, butyltrimethylammonium, pentyltrimethylammonium, hexyltrimethylammonium, heptyltrimethylammonium, octyltrimethylammonium, nonyltrimethylammonium, decyltrimethylammonium, undecyltrimethylammonium, dodecyltrimethylammonium, tridecyltrimethylammonium, tetradecyltrimethylammonium, heptadecyltrimethylammonium, hexadecyltrimethylammonium, heptadecyltrimethylammonium, and octadecyltrimethylammonium; hydroxylammonium compounds such as (2-hydroxypropyl)trimethylammonium, hydroxyethyltrimethylammonium, and trimethylaminoethoxyethanol; and alicyclic ammonium compounds such as 1-methyl-1-azania-4-azabicyclo[2,2,2]octanium, 1,1-dimethyl-4-methylpiperidinium, 1-methylmorpholinium, and 1-methylpiperidinium. Among these, tetramethylammonium, methyltriethylammonium, ethyltrimethylammonium, butyltrimethylammonium, hexyltrimethylammonium, octyltrimethylammonium, decyltrimethylammonium, dodecyltrimethylammonium, tetradecyltrimethylammonium, hexadecyltrimethylammonium, octadecyltrimethylammonium, (2-hydroxypropyl)trimethylammonium, hydroxyethyltrimethylammonium, 1-methyl-1-azania-4-azabicyclo[2,2,2]octanium, and 1,1-dimethyl-4-methylpiperidinium are preferably used because they have excellent catalytic activity and are industrially available.

The organic acid group or inorganic acid group constituting such a quaternary ammonium salt may, for example, be a formic acid group, an acetic acid group, an octylic acid group, an oxalic acid group, a malonic acid group, a succinic acid group, a glutaric acid group, an adipic acid group, a benzoic acid group, a toluic acid group, an ethylbenzoic acid group, a methylcarbonate group, a phenol group, an alkylbenzenesulfonic acid group, a toluenesulfonic acid group, a benzenesulfonic acid group, or a phosphate ester group, or an inorganic acid group such as a halogen group, a hydroxyl group, a hydrogencarbonate group, or a carbonate group. Among these, the formic acid group, the acetic acid group, the octylic acid group, the methylcarbonate group, the halogen group, the hydroxyl group, the hydrogencarbonate group, or the carbonate group is preferred because of its excellent catalytic activity and industrial availability.

In addition, various catalysts made of such quaternary ammonium salts are commercially available, such as U-CAT18X, U-CAT2313 (manufactured by San-Apro Co., Ltd.), Kao Raiser No. 410, and Kao Raiser No. 420 (manufactured by Kao Corporation).

In addition, the A liquid according to the present invention contains, as yet another essential component, a primary and/or secondary amino group-containing compound, which is an amine compound having a primary and/or secondary amino group, as a crosslinking agent. Here, the primary and/or secondary amino group-containing compound is not particularly limited as long as it is a compound that bonds and contains a primary and/or secondary amino group, and examples thereof include aliphatic amine compounds, aliphatic polyamine compounds, aromatic amine compounds, aromatic polyamine compounds, amino acids, alkanolamines, etc.

Specifically, examples of aliphatic amine compounds include linear amino group-containing compounds such as butylamine, octylamine, and dodecylamine, alicyclic amino group-containing compounds such as cyclohexylamine, and cyclic amino group-containing compounds such as piperidine. Examples of aliphatic polyamines include linear amino group-containing compounds such as butanediamine, hexanediamine, octanediamine, polyetheramine, triethylenetetramine, tetraethylenepentamine, hydrazine, 1,2-diaminopropane, 1,3-diaminopropane, tetramethylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, and diethylenetriamine, alicyclic amino group-containing compounds such as cyclohexanediamine, norbornenediamine, 4,4'-diaminocyclohexylmethane, isophoronediamine, and bisaminomethylcyclohexane, cyclic amino group-containing compounds such as piperazine, and aliphatic amino group-containing compounds having an aromatic ring such as xylylenediamine. Further, examples of aromatic amine compounds include amino group-containing compounds such as aniline, toluidine, anisidine, and methylaniline. Further, examples of aromatic polyamine compounds include amino group-containing compounds such as toluenediamine, methylenedianiline, phenylenediamine, diaminodiphenylmethane, diaminodiphenylether, trimethylphenylenediamine, diethyltoluenediamine, dimethylthiotoluenediamine, 4,4'-methylenebis(N-sec-butylaniline), aminobenzylamine, and methylenebis(ethylmethylaniline). Further, examples of amino acids include compounds containing a carboxyl group and an amino group in the molecule such as lysine, valine, and asparagine. In addition, examples of alkanolamine compounds include compounds having an amino group and a hydroxyl group in the molecule such as ethanolamine, hexanolamine, and diethanolamine. In addition, examples of the polyoxyalkylene diamines include those obtained by converting the hydroxyl groups of polyoxyalkylene glycols obtained by addition polymerization of propylene oxide and/or ethylene oxide to water, ethylene glycol, propylene glycol, etc., into amino groups, and those obtained by converting the hydroxyl groups of polyoxyalkylene triols obtained by addition polymerization of propylene oxide and/or ethylene oxide to glycerin, trimethylolpropane, etc., into amino groups. These amine compounds having primary and/or secondary amino groups can be used alone or in combination of two or more types.

In the present invention, the primary and/or secondary amino group-containing compound as described above is preferably a polyamine compound having two or more primary and/or secondary amino groups in one molecule in order to effectively exert the function as a crosslinking agent, and is preferably an amine compound having an aromatic ring (aromatic amine compound) in order to improve the reactivity and flame retardancy, and is more preferably an aromatic polyamine compound. Among them, an aromatic polyamine compound having a structure in which at least one of the positions adjacent to the amino group bonded to the aromatic ring is substituted with an alkyl group is particularly preferably used. Among such primary and/or secondary amino group-containing compounds, a compound containing a primary amino group is more preferably used.

In addition, in the present invention, among the primary and/or secondary amino group-containing compounds as described above, compounds having a primary and/or secondary amino group amount of 0.5 to 50 mmol/g, preferably 1 to 20 mmol/g, and more preferably 3 to 15 mmol/g are advantageously used. If the primary and/or secondary amino group amount is less than 0.5 mmol/g, it may be difficult to fully achieve the object of the present invention, and if it is more than 50 mmol/g, the crosslinking reaction may proceed too far, causing an abnormal reaction, solidifying the liquid during injection, and causing problems such as not being able to obtain an effective foam.

Furthermore, such primary and/or secondary amino group-containing compounds are generally preferably contained in Liquid A in a ratio of 0.01 to 20 parts by mass, preferably 0.05 to 10 parts by mass, and more preferably 0.1 to 5 parts by mass, per 100 parts by mass of the polyisocyanate in Liquid B. If the content is less than 0.01 parts by mass, the reaction between the amino groups in the primary and/or secondary amino group-containing compounds and the isocyanate groups in the polyisocyanate in Liquid B will be insufficient, and the strength of the resulting solidified body will be insufficient, or the reaction will not proceed sufficiently, resulting in insufficient formation of the reaction product (foam). If the content exceeds 20 parts by mass, crosslinking in the reaction product will proceed too far, causing an abnormal reaction, which will cause solidification during the injection operation, and the desired foam will not be formed.

In addition to the amine compounds described above, the solution A according to the present invention can further contain various known active hydrogen group-containing compounds as necessary. Among them, various known polyols that can react with the polyisocyanate component are preferably used.

Such polyols are not particularly limited, and those that have been used as polyol components in conventional ground consolidation chemicals can be used in the same way, such as known polyether polyols and polyester polyols. These polyols can be used alone or in appropriate combinations. The amount of polyol added and mixed will be selected appropriately so as not to deviate from the spirit of the present invention, but is generally about 40 parts by mass or less, preferably 30 parts by mass or less, and more preferably 20 parts by mass or less, per 100 parts by mass of the silicate aqueous solution.

The above-mentioned polyether polyols are not particularly limited, but examples thereof include polyhydric alcohols having at least two or more active hydrogen groups, such as ethylene glycol, propylene glycol, glycerin, trimethylolpropane, and pentaerythritol; amines, such as ethylenediamine; and alkanolamines, such as ethanolamine and diethanolamine, which are produced by addition reaction of the starting material with an alkylene oxide, such as ethylene oxide or propylene oxide. In addition, the polyester polyols are not particularly limited, but examples thereof include polycarboxylic acid-based polyester polyols obtained by reacting polyhydric alcohols with polycarboxylic acids, such as succinic acid, adipic acid, sebacic acid, maleic acid, phthalic acid, terephthalic acid, trimellitic acid, and dimer acid; lactone-based polyester polyols obtained by ring-opening polymerization of lactones, and castor oil-based polyester polyols.

On the other hand, as the polyisocyanate, which is an essential component of the other of the two liquids constituting the ground injection liquid composition of the present invention, liquid B, an aromatic polyisocyanate is used in the present invention from the viewpoint of the strength and reaction speed of the reaction product (foam) obtained by the reaction with liquid A. Here, the aromatic polyisocyanate is an organic isocyanate compound having two or more isocyanate groups (NCO groups) in the molecule, and various known ones are appropriately selected and used. For example, diphenylmethane diisocyanate (MDI), polymethylene polyphenylene polyisocyanate (crude MDI), tolylene diisocyanate, polytolylene polyisocyanate, xylylene diisocyanate, naphthalene diisocyanate, etc. can be mentioned, and also prepolymers, isocyanurate modified products, carbodiimide modified products, etc. of these aromatic polyisocyanates can be mentioned. These polyisocyanate components may be used alone or in combination of two or more kinds, but in general, MDI and crude MDI are preferably used from the viewpoints of reactivity, economy, ease of handling, etc. In addition to using only such aromatic polyisocyanates as the polyisocyanate in liquid B, other known polyisocyanate components can also be used in combination as long as they do not deviate from the spirit of the present invention.

The aromatic polyisocyanate as such a polyisocyanate is generally contained in Liquid B at a ratio of 50 to 100% by mass, preferably 70 to 100% by mass, and more preferably 80 to 100% by mass. If the content of this aromatic polyisocyanate is less than 50% by mass, there is a problem that the strength of the reaction product decreases, so it is desirable for the ratio of aromatic polyisocyanate in Liquid B to be high, and it is also possible to constitute Liquid B only with such aromatic polyisocyanate.

Incidentally, the above-mentioned A and B liquids constituting the ground consolidation liquid according to the present invention can be added with additives similar to those used in the past, depending on the intended use. For example, additives for A liquid can include foaming agents, foam stabilizers, flame retardants, viscosity reducers, etc. Such additives for A liquid are used in a ratio of 0.1 to 30 parts by mass, preferably 0.5 to 20 parts by mass, per 100 parts by mass of polyisocyanate. Additives for the B liquid include foam stabilizers, flame retardants, viscosity reducers, etc., of which the foam stabilizer is used in an amount of 0.05 to 5 parts by mass, preferably 0.1 to 3 parts by mass, per 100 parts by mass of polyisocyanate, the viscosity reducer is used in an amount of 0.5 to 60 parts by mass, preferably 1 to 40 parts by mass, per 100 parts by mass of polyisocyanate, and the flame retardant is used in an amount of 1 to 50 parts by mass, preferably 5 to 40 parts by mass, per 100 parts by mass of polyisocyanate.

Of these additives, known foaming agents such as water, hydrocarbons, hydrofluorocarbons, hydrofluoroolefins, and hydrochlorofluoroolefins can be used. The foaming agent is not particularly limited, but water is preferably used. This water is also supplied from the silicate aqueous solution that constitutes Liquid A, and reacts with the polyisocyanate in Liquid B to generate carbon dioxide gas, so that it functions as a foaming agent.

The foam stabilizer is used to uniformly adjust the cell structure of the foam formed by the reaction of liquid A and liquid B. Examples of the foam stabilizer include silicone, nonionic surfactants, polyoxyalkylene-modified dimethylpolysiloxane, polysiloxane oxyalkylene copolymer, polyoxyethylene sorbitan fatty acid ester, castor oil ethylene oxide adduct, lauryl fatty acid ethylene oxide adduct, etc., and among these, silicone and nonionic surfactants are preferably used. These may be used alone or in combination of two or more. Among the foam stabilizers, silicone-based foam stabilizers are more preferable, and polyoxyalkylene-modified dimethylpolysiloxane, polysiloxane oxyalkylene copolymer, etc. are preferable.

Furthermore, examples of flame retardants include bromine-based flame retardants, chlorine-based flame retardants, phosphorus-based flame retardants, halogenated phosphate esters, inorganic flame retardants, etc. These may be used alone or in combination of two or more. Among these, phosphate esters and halogenated phosphate esters are preferably used because they have a low environmental impact and also function as a viscosity reducer for the foamable composition. Examples of phosphate esters include trimethyl phosphate, triethyl phosphate, tributyl phosphate, trixylenyl phosphate, etc. Furthermore, examples of halogenated phosphate esters include tris(chloroethyl)phosphate, tris(2-chloropropyl)phosphate, tris(dichloropropyl)phosphate, tetrakis(2-chloroethyl)dichloroisopentyl diphosphate, polyoxyalkylene bis(dichloroalkyl)phosphate, etc.

In addition, the viscosity reducer is used as a solvent, and is dissolved in liquid A or liquid B to reduce the viscosity of those liquids. As long as it has such a function, there are no particular limitations on the type of viscosity reducer, and examples of such viscosity reducers include alcohols such as methanol and ethanol, ethers such as ethyl cellosolve and butyl cellosolve, cyclic esters such as propylene carbonate, esters such as dicarboxylic acid methyl esters and ethylene glycol monomethyl ether acetate, petroleum hydrocarbons, etc. These may be used alone or in combination of two or more types.

Meanwhile, each of the solutions A and B prepared according to the present invention is adjusted so that its viscosity at a temperature of 25°C is 400 mPa·s or less, preferably 5 to 300 mPa·s, and more preferably 10 to 200 mPa·s. If the viscosity is higher than 400 mPa·s, problems such as increased pressure loss when injected into the ground and difficulty in injection work will occur. If the viscosity is too low, the solution will be easily diluted with water, and problems such as cloudy drainage will easily occur.

In addition, when using the liquid composition for ground injection according to the present invention, which is composed of such liquid A and liquid B, the two liquids are mixed at the time of use, injected into the target ground, rock, etc., according to a known method, and reacted and hardened to form a high-strength solidified body. The mixing ratio (A:B) of liquid A and liquid B is changed appropriately depending on the active oxygen group content in liquid A and the NCO group content in liquid B, but is generally adopted within the range of A:B = 2:1 to 1:3, preferably 1:1 to 1:2, on a mass basis. There are also no particular restrictions on the method of using liquid A and liquid B, so long as the method can reliably mix the two liquids immediately before use, and various conventionally known injection methods can be appropriately adopted.

The liquid chemical composition according to the present invention is configured so that when liquid A and liquid B are mixed, a cured reaction product (foam) is formed at 20°C with a foaming ratio of generally 20 times or less, preferably 3 to 15 times. However, if the foaming ratio becomes too high, problems such as a decrease in the compressive strength and other properties of the resulting foam may occur.

Furthermore, the reaction time when liquid A and liquid B are mixed and foamed, in other words the rise time, is preferably within 300 seconds, with a lower limit of about 20 seconds. If the rise time is longer than 300 seconds, problems such as the liquid flowing out into the spring water after being injected into the ground and before it solidifies can occur, causing the water to become cloudy or foaming. Note that if the rise time is too short, for example, shorter than 20 seconds, the reaction will proceed too quickly, causing problems such as blocking the injection pipe for the liquid or making it difficult to fully penetrate the ground, so care must be taken.

Below, we will present some examples and comparative examples of the present invention to clarify the present invention in more detail, but it goes without saying that the present invention is not limited in any way by the description of such examples. Furthermore, it should be understood that in addition to the examples below and the specific description above, various changes, modifications, improvements, etc. can be made to the present invention based on the knowledge of those skilled in the art, as long as they do not deviate from the spirit of the present invention.

In addition to the properties (viscosity) of the A and B liquids obtained in the following examples and comparative examples, the expansion ratio of the reaction product when the A and B liquids are mixed and reacted to harden, the rise time, expansion ratio ratio, compressive strength and oxygen index of the reaction product were measured or evaluated according to the following methods. In addition, the "%" and "parts" shown below are all based on mass.

(1) Viscosity The viscosities of the A and B liquids obtained in the Examples and Comparative Examples were measured using a B-type viscometer in accordance with JIS-K-7117-1.

(2) Expansion ratio and rise time (reaction time)
After adjusting the liquid temperature of each of the various A and B liquids shown in the table below to 20°C or 35°C, 100 ml in total was weighed into a 1 L cup at the mixing ratio shown below, and stirred for 10 seconds at 400 rpm by hand mixing. The rise time (reaction time) was determined as the time from the start of stirring to the time when the foam height reached its maximum. The foam height of the reaction product after the curing reaction was visually measured to determine the foaming ratio. Furthermore, the ratio of the foaming ratio at 20°C to the foaming ratio at 35°C was calculated. A foam stable against temperature changes was obtained when the 20°C/35°C foaming ratio was in the range of 0.7 to 1.3.

(3) Foaming stability during foaming at high temperature (35°C) Liquids A and B having the compositions shown in the tables below were adjusted to a liquid temperature of 35°C, and then mixed in the mixing ratios shown in each table to make a total of 100 ml, which was then poured into a 1 L cup. The foaming and hardening process was observed while stirring, and the foaming ratio after the reaction was completed was compared with the maximum foaming ratio during foaming. The foaming stability was evaluated by rating the shrinkage within 10% of the maximum foaming ratio as "◎", within 20% as "◯", and over 20% as "X".

(4) Compressive strength Liquid A and liquid B adjusted to a temperature of 20°C were weighed and mixed in the mixing ratio shown in the table below so that the total amount was 100 ml. Then, immediately after such mixing, a predetermined amount of the mixture of liquid A and liquid B was poured into a bottomed cylindrical mold with an inner diameter of 50 mm and a height of 100 mm so that the expansion ratio was three times the amount, and after covering, it was cured for 2 hours or more. Thereafter, the reaction product removed from the mold was cured at 20°C for 24 hours or more, and the compressive strength was measured in accordance with JIS-K-7220:2006.

(5) Oxygen Index Using the foam prepared for the above-mentioned compressive strength measurement, a test specimen having a size of 10 mm x 10 mm x 150 mm was cut out, and the oxygen index (%) was measured in accordance with JIS-K-7201-2. This oxygen index is used to evaluate the flame retardancy of the foam, and if the value is 27% or more, it is judged to have good flame retardancy.

First, the following various raw materials were prepared as components of the A and B solutions used in the following examples and comparative examples.
Silicate aqueous solution: No. 1 sodium silicate I (product of Fuji Chemical Co., Ltd., molar ratio: 2.1, solid content: 48%; water was added to adjust the solid content to approximately 40%.)
: No. 1 sodium silicate II (product of Fuji Chemical Co., Ltd., molar ratio: 2.1, solid content: 48%, water was added to adjust the solid content to approximately 45%)
: No. 2 sodium silicate (product of Fuji Chemical Co., Ltd., molar ratio: 2.5, solid content: 40%)
Tertiary amine catalyst: Kao Raiser No. 26 (Kao Corporation product, N,N-dimethylaminoethoxyethanol, MW: 133.2)
: Kao Raiser No. 1 (Kao Corporation product, N,N,N',N'-tetramethylhexamethylenediamine, MW: 172.3)
Primary/secondary amino group-containing compound: Polyetheramine T403 (polyetheramine, BASF product, molecular weight: 400, functional group: NH ₂ × 3)
: Ethacure 100 (diethyltoluenediamine, product of Albemarle, molecular weight: 178, functional group: _NH2 x 2)
: Ethacure 300 (diethylthiotoluenediamine, Albemarle product, molecular weight: 214, functional group: _NH2 x 2)
: Ethacure 420 [4,4'-methylenebis(N-sec-butylaniline), manufactured by Albemarle Corporation, molecular weight: 310, functional group: NH x 2]
: n-Octylamine [product of Tokyo Chemical Industry Co., Ltd., molecular weight 129.3, functional group: NH ₂ × 1]
Polyol: PG (propylene glycol, product of Tokyo Chemical Industry Co., Ltd.)
PP400 (Sanyo Chemical Industries, Ltd. product, Sannix PP400, polyether polyol, molecular weight: 400, number of functional groups: 2)
: PP1000 (product of Sanyo Chemical Industries, Ltd., Sannix PP1000, polyester polyol, molecular weight: 1000, number of functional groups: 2)
: EDP1100 (A product of ADEKA Corporation, ADEKA Polyol EDP1100, polyether polyol, molecular weight: 1100, number of functional groups: 4)
Aromatic polyisocyanate: Lupranate M11S (BASF INOAC Polyurethanes Co., Ltd. product, Polymeric MDI)
: Luplanate M20S (BASF INOAC Polyurethanes Co., Ltd. product, polymeric MDI)
Prepolymer (obtained by adding 5 parts of the above-mentioned PP1000 to 100 parts of Luplanate M11S and reacting at a temperature of 70° C. for 3 hours)
Aliphatic polyisocyanate: Takenate D-170N (Mitsui Chemicals, Inc. product, isocyanurate of hexamethylenediamine diisocyanate)
Foam stabilizer: L-6970 (Momentive Performance Materials Japan LLC product, silicone-based foam stabilizer)
Viscosity reducer: PC (Tokyo Chemical Industry Co., Ltd. product, propylene carbonate)
Flame retardant: TMCPP [product of Daihachi Chemical Industry Co., Ltd., tris(2-chloropropyl)phosphate]

(Examples 1 to 19)
- Preparation of solution A -
The various raw materials prepared above, i.e., the silicate aqueous solution, the tertiary amine catalyst, the primary/secondary amino group-containing compound, and the polyol, were uniformly mixed in the various combinations and blending ratios shown in Tables 1 to 4 below, to prepare various A-liquid blend compositions according to Examples 1 to 19. The viscosities of the obtained A-liquid blend compositions at 25°C were then measured, and the results are shown in Tables 1 to 4 below.

- Preparation of solution B -
The various raw materials prepared above, i.e., aromatic polyisocyanate, foam stabilizer, viscosity reducer, and flame retardant, were uniformly mixed in the various combinations and blending ratios shown in Tables 1 to 4 below to prepare various B liquid blend compositions according to Examples 1 to 19. The viscosity of the obtained B liquid blend compositions at 25°C was then measured, and the results are shown in Tables 1 to 4 below.

-Reaction of solution A and solution B-
The A and B solutions obtained above were mixed uniformly in the mixing ratios shown in Tables 1 to 4 at room temperature (20°C) or at a high temperature (35°C) to react with each other, and then various evaluation tests were carried out according to the above-mentioned evaluation methods. The results are shown in Tables 1 to 4 below.

(Comparative Example 1)
The tests were carried out in the same manner as in Example 1, except that the primary/secondary amino group-containing compound was not added. The results are shown in Table 5 below.

(Comparative Example 2)
Tests were carried out in the same manner as in Example 13, except that the primary/secondary amino group-containing compound was not added. The results are shown in Table 5 below.

(Comparative Example 3)
The tests were carried out in the same manner as in Example 1, except that the tertiary amine catalyst was not added. The results are shown in Table 5 below.

(Comparative Example 4)
Tests were carried out in the same manner as in Example 1, except that Takenate D-170N, an aliphatic polyisocyanate, was used instead of the aromatic polyisocyanate in Example 1, and the results are shown in Table 5 below.

As is clear from the results in Tables 1 to 4, the liquid chemical compositions consisting of Liquid A and Liquid B according to the present invention in Examples 1 to 19 all have excellent reaction activity with a reaction time of 300 seconds or less, and can form a hardened product (foam) with high compressive strength and excellent oxygen index (flame retardancy) at an expansion ratio of about 3 times or more. Furthermore, they have excellent reaction time and expansion ratio when expanded at a high temperature of 35°C, and as a result, the 20°C/35°C expansion ratio ratio is within the range of 0.7 to 1.3, showing the result that a foam stable against temperature changes can be formed.

In contrast, as shown in Table 5, the liquid chemical compositions prepared in Comparative Examples 1 to 4, consisting of Liquid A and Liquid B, did not produce a cured product (foam) with sufficient compressive strength or oxygen index (flame retardancy), and in addition, the foam significantly shrunk when foamed at high temperature at 35°C, and the 20°C/35°C foaming ratio ratio was outside the range of 0.7 to 1.3, making it difficult to expect the formation of a foam that was stable against temperature changes. In the liquid chemical composition of Comparative Example 3, since no tertiary amine catalyst was added, the cured product (foam) obtained was easily crumbled and brittle, making it impossible to measure the compressive strength or oxygen index. In Comparative Example 4, which used an aliphatic polyisocyanate, the rise time during foaming at room temperature exceeded 300 seconds, and in addition to the problem of a long reaction time, there were problems such as a low foaming ratio and insufficient compressive strength.

Claims (8)

A liquid composition for ground injection comprising liquid A containing an aqueous silicate solution and a catalyst as essential components, and liquid B containing a polyisocyanate as an essential component,
A ground injection liquid composition, characterized in that an aromatic polyisocyanate is used as the polyisocyanate, which is an essential component of the B liquid, and the A liquid contains a tertiary amine as the catalyst and further contains a primary and/or secondary amino group-containing compound. The liquid composition for ground injection according to claim 1, characterized in that the primary and/or secondary amino group-containing compound is a polyamine compound having two or more primary and/or secondary amino groups in one molecule. The liquid composition for ground injection according to claim 1 or 2, characterized in that the primary and/or secondary amino group-containing compound has primary and/or secondary amino groups in a ratio of 0.5 to 50 mmol/g. The liquid composition for ground injection according to any one of claims 1 to 3, characterized in that the primary and/or secondary amino group-containing compound is an aromatic amine compound. The liquid composition for ground injection according to any one of claims 1 to 4, characterized in that the primary and/or secondary amino group-containing compound is contained in a ratio of 0.01 to 20 parts by mass per 100 parts by mass of the polyisocyanate. The liquid composition for ground injection according to any one of claims 1 to 5, characterized in that the tertiary amine as the catalyst has an alcoholic hydroxyl group. The liquid composition for ground injection according to any one of claims 1 to 6, characterized in that the liquid A further contains a polyol. The liquid composition for ground injection according to any one of claims 1 to 7, characterized in that each of the liquids A and B has a viscosity of 400 mPa·s or less at a temperature of 25°C.