JP2023010510A - Urethane-based grout - Google Patents

Abstract

To provide an urethane-based grout which forms a foam curable resin with low viscosity in the presence of water, and exhibits excellent water-cutoff performance.SOLUTION: An urethane-based grout contains, as a main component, an urethane prepolymer having a terminal isocyanate group obtained by reacting polyol with at least one organic polyisocyanate selected from diphenylmethane diisocyanate, polymethylene polyphenyl polyisocyanate and their modified bodies, so that NCO/OH is 1.5 to 2.0, wherein the polyol contains polyol A which is produced by addition polymerization of a single ethylene oxide with polyhydric alcohol or addition polymerization of an ethylene oxide and an alkylene oxide having 3 or 4 carbon atoms, and has a number average molecular weight of 800 or more and 7,000 or less, polyol B which is produced by addition polymerization of a propylene oxide with polyhydric alcohol or polyhydric phenol and has a number average molecular weight of 300 or more and 5,000 or less, and bifunctional polyol which has a number average molecular weight of less than 300.SELECTED DRAWING: None

Description

The present invention relates to a urethane-based injection agent, and more specifically, it has a viscosity as low as that of conventional MDI-based urethane prepolymers, forms a foam in the presence of water, and exhibits excellent water stopping properties. It relates to a urethane-based injection agent.

Urethane-based grouting agents are widely used for sealing water in tunnel construction, filling cavities, waterproofing cracked concrete structures, and so on. Among them, injection agents mainly composed of lipophilic urethane prepolymers can foam and harden with a small amount of chemical solution, efficiently fill relatively large gaps such as the back of tunnels, and exhibit a high waterproofing effect.

In recent years, MDI isocyanates such as 4,4'-diphenylmethane diisocyanate have been widely used as organic polyisocyanates constituting urethane prepolymers. However, unreacted diphenylmethane diisocyanate (MDI) monomer remains in the conventional urethane prepolymer-type injection agent, which may impair the working environment of workers.

In order to reduce the unreacted MDI monomer, a method of producing a prepolymer by reacting an excess amount of MDI with a diol having a relatively high molecular weight and distilling off free MDI under reduced pressure (Patent Document 1), or a prepolymer reaction. A method has been proposed in which the product is distilled in the presence of at least one inert solvent having a boiling point slightly lower than that of the monomeric diisocyanate (US Pat. However, since these methods remove the high-boiling MDI while avoiding thermal decomposition of the prepolymer, an expensive purification step such as thin-film distillation is required.

On the other hand, if the stoichiometric reaction equivalent ratio (NCO/OH) of polyol and MDI is set to 2.0 or less, MDI does not theoretically remain in the prepolymer, but oligomers are formed during the reaction to increase the viscosity. or the long-term stability of the resulting prepolymer is impaired.
As a method for producing a reactive polyurethane with a low monomeric diisocyanate content that does not involve a post-treatment process or a purification process, a monomeric diisocyanate containing 2,4'-MDI as a main component and a diol having a molecular weight of 60 to 2000 are combined with an NCO. A method of reacting at a /OH ratio of 1.05/1 to 2.0/1 has been proposed (Patent Document 3).
In addition, as a method for producing a 2,4'-MDI prepolymer having a low viscosity and a low monomer content, 2,4'-MDI is reacted with a polyether polyol having an average functionality of 3 to 8 at an NCO/OH ratio of less than 2. A method (Patent Document 4) has been proposed.

JP-A-8-176252 Japanese Patent Publication No. 2003-515635 Japanese Patent Publication No. 2004-534132 JP-A-2006-37099

The NCO group at the 2-position of 2,4'-MDI used in Patent Documents 3 and 4 is located at a position that is difficult to react sterically, and is therefore less reactive than the NCO group at the 4'-position. Therefore, the NCO group at the 4'-position preferentially reacts to form a prepolymer, and a low-viscosity urethane prepolymer can be obtained without excessively blending MDI, and residual monomers can also be reduced. However, when such a urethane prepolymer is used as an injection agent, the reactivity of the unreacted NCO group at the 2-position is low, so that the curing speed is slowed and a sufficient waterproofing effect cannot be obtained.
In addition, since the urethane prepolymer with a small residual MDI monomer originally has a low NCO content (the amount of NCO groups per unit mass), it is difficult to cure in the presence of a large amount of water.

Therefore, the residual amount of MDI monomer is reduced, and this urethane-based injection agent has a viscosity as low as conventional MDI-based urethane prepolymers, foams and cures in the presence of water, and has void-filling and water-stopping properties. It wasn't until
The present invention provides a urethane-based injection agent with reduced residual MDI monomer, a viscosity as low as that of conventional MDI-based urethane prepolymers, foaming and curing in the presence of water, and exhibiting excellent water stopping properties. This is the subject.

The present inventors have made intensive studies to solve the above problems, and found that a urethane prepolymer obtained by reacting a combination of predetermined polyols with an MDI-based isocyanate containing polymethylene polyphenyl polyisocyanate has a low The present inventors have completed the present invention based on the finding that a hardening foam is formed with high viscosity and in the presence of water and exhibits excellent water stopping properties.

That is, the present invention relates to the following [1] to [10].

[1] a polyol and at least one organic polyisocyanate selected from the group consisting of diphenylmethane diisocyanate, polymethylene polyphenyl polyisocyanate and modified products thereof,
A urethane injection agent mainly composed of a urethane prepolymer having a terminal isocyanate group obtained by reacting such that the equivalent ratio (NCO/OH) of the isocyanate group and the hydroxy group is 1.5 to 2.0. ,
The polyol is a polyol A having a number average molecular weight of 800 or more and 7,000 or less obtained by addition polymerization of ethylene oxide alone or ethylene oxide and alkylene oxide having 3 or 4 carbon atoms to a polyhydric alcohol;
Polyol B having a number average molecular weight of 300 or more and 5,000 or less, obtained by addition polymerization of propylene oxide alone or ethylene oxide and propylene oxide to a polyhydric alcohol or polyhydric phenol at a ratio of 80% by mass or more of propylene oxide. When,
a bifunctional low-molecular-weight polyol having a number average molecular weight of less than 300,
The organic polyisocyanate contains polymethylene polyphenyl polyisocyanate,
Urethane injection.
[2] The urethane injection agent according to [1], wherein the organic polyisocyanate contains 20 to 70% by mass of polymethylene polyphenyl polyisocyanate.
[3] The urethane-based injection agent according to [1] or [2], wherein the residual unreacted 4,4'-diphenylmethane diisocyanate is 5% by mass or less.
[4] The polyol A is at least one polyhydric alcohol selected from the group consisting of ethylene glycol, propylene glycol, diethylene glycol, and dipropylene glycol combined with ethylene oxide alone or ethylene oxide and alkylene having 3 or 4 carbon atoms. The urethane-based injection agent according to any one of [1] to [3], which is obtained by addition polymerization of an oxide.
[5] The polyol B is at least one polyhydric alcohol or polyhydric phenol selected from the group consisting of glycerin, diglycerin, pentaerythritol, trimethylolpropane, sorbitol, and bisphenol A, and propylene oxide alone or The urethane-based injection agent according to any one of [1] to [4], which is obtained by addition polymerization of ethylene oxide and propylene oxide at a ratio of 80% by mass or more of propylene oxide.
[6] The low-molecular-weight polyol is at least one selected from the group consisting of ethylene glycol, propylene glycol, diethylene glycol, 1,3-propanediol, and 1,4-butanediol, [ 1] The urethane-based injection agent according to any one of [5].
[7] The urethane injection agent according to any one of [1] to [6], which further contains a diluent.
[8] The diluent is propylene carbonate, gamma-butyl lactone, vegetable oil-based fatty acid ester, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, triethylene glycol butyl methyl ether, 2-oxo-4-methyl-1,3-dioxolane, glutar The urethane injection agent according to [7], which is at least one selected from the group consisting of dimethyl acid, dimethyl succinate and dimethyl adipate.
[9] The urethane injection agent according to any one of [1] to [8], which further contains a monoisocyanate.
[10] The urethane injection agent according to any one of [1] to [9], which further contains a curing accelerator.

The urethane-based injection agent of the present invention has a reduced amount of residual MDI monomer, has a viscosity as low as that of conventional MDI-based urethane prepolymers, forms a foamed cured product in the presence of water, and exhibits an excellent waterproofing effect. Demonstrate.

The urethane prepolymer having a terminal isocyanate group, which is used as the main component of the urethane injection agent of the present invention, is selected from the group consisting of a combination of three polyols, diphenylmethane diisocyanate, polymethylene polyphenyl polyisocyanate, and modified products thereof. It is obtained by reacting with one organic polyisocyanate containing at least polymethylene polyphenyl polyisocyanate.

<Polyol>
The polyols used in the present invention include polyol A obtained by adding ethylene oxide alone or ethylene oxide and alkylene oxide having 3 or 4 carbon atoms to a polyhydric alcohol, and propylene oxide alone or ethylene oxide in a polyhydric alcohol or polyhydric phenol. and propylene oxide, and a polyol B obtained by addition polymerization of propylene oxide in a proportion of 80% by mass or more, and a low-molecular-weight polyol are essentially contained.

<Polyol A>
Polyol A is a polyol having a number average molecular weight of 800 or more and 7,000 or less, obtained by addition polymerization of ethylene oxide to a polyhydric alcohol or ethylene oxide and an alkylene oxide having 3 or 4 carbon atoms.
Polyhydric alcohols include ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1,3- and 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, glycerin, diglycerin, trimethylolpropane, Sorbitol, pentaerythritol, cyclohexanedimethanol.
Among these, ethylene glycol, propylene glycol, diethylene glycol, and dipropylene glycol are preferred because they do not increase the viscosity during prepolymerization.

The alkylene oxide having 3 or 4 carbon atoms includes propylene oxide, 1,2-, 1,3-, 1,4- or 2,3-butylene oxide. Only ethylene oxide may be added without adding these alkylene oxides, or ethylene oxide and two or more of these alkylene oxides may be used in combination (block or random addition). Among these, it is preferable to use ethylene oxide and propylene oxide in combination, and it is more preferable to use them in the form of block addition. When ethylene oxide and an alkylene oxide having 3 or 4 carbon atoms are used in combination, the proportion of ethylene oxide is preferably 10% by mass or more, more preferably 20% by mass or more, based on the total mass of the added alkylene oxide. Preferably, it is more preferably 30% by mass or more.

The number average molecular weight of polyol A is preferably 1,000 or more and 5,000 or less, more preferably 1,500 or more and 4,500 or less.

The content of polyol A increases the affinity with water and evenly incorporates water into the entire resin, making the foam finer when hardening and increasing the water stoppage, and the resulting urethane prepolymer is less likely to thicken. From the viewpoint of reducing the amount of polyol, it is preferably used in an amount of 3 to 70% by mass, more preferably 5 to 40% by mass.

<Polyol B>
Polyol B is obtained by addition polymerization of propylene oxide alone or ethylene oxide and propylene oxide to polyhydric alcohol or polyhydric phenol at a rate of propylene oxide being 80% by mass or more. is a polyol of
Examples of the polyhydric alcohol include those exemplified as the polyhydric alcohol which is the starting material of the polyol A.
Polyhydric phenols include monocyclic polyhydric phenols such as pyrogallol, hydroquinone, resorcin and phloroglucin; bisphenols such as bisphenol A and bisphenolsulfone;
Among these, glycerin, diglycerin, pentaerythritol, trimethylolpropane, sorbitol, and bisphenol A are preferred from the viewpoint of increasing resin strength and stabilizing foamability.
When ethylene oxide and propylene oxide are used in combination, the proportion of propylene oxide is preferably 80% by mass or more, more preferably 90% by mass or more, based on the total mass of the added alkylene oxides.

The content of polyol B is 3 to the total amount of polyol from the viewpoint of increasing affinity with MDI isocyanate, exhibiting lipophilicity in order to improve water stoppage, and making it difficult for the resulting urethane prepolymer to thicken. It is preferable to use up to 70% by mass, more preferably 5 to 60% by mass.

<Low-molecular-weight polyol>
By further using a bifunctional low-molecular-weight polyol having a number average molecular weight of less than 300 as the polyol component, the curability of the urethane prepolymer can be enhanced. Low-molecular-weight polyols include ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, 1,3-propanediol, and 1,4-butanediol.

The content of the low-molecular-weight polyol is preferably 10 to 95% by mass, more preferably 30 to 90% by mass, based on the total amount of polyol, from the viewpoint of curability and product stability of the urethane prepolymer.

Polyols other than those described above can be used as long as the objects of the present invention are not impaired. Such polyols are not particularly limited, but include polyether polyols other than the polyol A and polyol B, polyester polyols, polycarbonate polyols, and polyacetal polyols. When these polyols are used, they are preferably used in an amount of 0 to 30% by mass based on the total amount of polyols.

The polyether polyol has a structure in which an alkylene oxide having 2 to 4 carbon atoms is added to a compound having two or more active hydrogen atoms (for example, polyhydric alcohol, polyhydric phenol, amine, etc.) (polyoxyalkylene chain have) compounds and mixtures thereof.
Polyhydric alcohols include ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, neopentyl glycol, glycerin, trimethylolpropane, pentaerythritol, sorbitol, 1,3- and 1,4-butanediol, 1,2- and 1,5-pentanediol, 1,6-hexanediol, 1,4-cyclohexanedimethanol and the like.
Here, it is preferable to use dipropylene glycol, glycerin, and trimethylolpropane as polyhydric alcohols from the viewpoint of improving the waterproof performance.
Examples of alkylene oxides having 2 to 4 carbon atoms include ethylene oxide, propylene oxide, 1,2-, 1,3-, 1,4- and 2,3-butylene oxide.
Among these polyether polyols, those having a number average molecular weight of 100 to 50,000 are preferred, and those having a number average molecular weight of 200 to 20,000 are more preferred.

Polyester polyols include polyols such as ethylene glycol, propylene glycol, butylene glycol, hexylene glycol, diethylene glycol, dipropylene glycol, neopentyl glycol, glycerin or trimethylolpropane, and succinic acid, glutaric acid, adipic acid, maleic acid, fumaric acid, and the like. Acids, saturated or unsaturated polyvalent carboxylic acids such as phthalic acid, or condensation products thereof with acid anhydrides, polycaprolactone polyols, and the like can be mentioned. These polyester polyols can also be used in combination of two or more if necessary. Among these, those having a number average molecular weight of 100 to 50,000 are particularly preferred, and those having a number average molecular weight of 200 to 20,000 are more preferred.

Polycarbonate polyols include those obtained by reacting a polyol such as ethylene glycol, propylene glycol, butylene glycol, hexylene glycol, diethylene glycol or dipropylene glycol with diethylene carbonate, dimethyl carbonate, diethyl carbonate or the like. These polycarbonate polyols can also be used in combination of two or more if necessary.

（式中、ｎは１以上の整数を示し、好ましくは１～５整数である。）
ポリメチレンポリフェニルポリイソシアネートは、ポリメリックジフェニルメタンジイソシアネート（ポリメリックＭＤＩ）と称されることもあり、二核体と称される１分子中にベンゼン環及びイソシアネート基を各２個有するジフェニルメタンジイソシアネート（モノメリックＭＤＩ）との混合物であってもよい。
ジフェニルメタンジイソシアネートの変性体としては、イソシアネート基の一部をビウレット、アロファネート、カルボジイミド、オキサゾリドン、アミド、イミド、イソシアヌレート、ウレトジオン等で変性したものが挙げられる。
これらの中でも、親油性を高め、樹脂強度を上げる観点から、ＭＤＩ系イソシアネートの総質量に対して、ポリメチレンポリフェニルポリイソシアネートを２０質量以上含有するものが好ましく、３０質量以上含有するものがより好ましく、４０質量以上含有するものがさらに好ましい。
また、得られるウレタンプレポリマーの粘性の観点から、ＭＤＩ系イソシアネートの総質量に対して、ポリメチレンポリフェニルポリイソシアネートを７０質量％以下含有するものが好ましく、６０質量％以下含有するものがより好ましい。 <MDI isocyanate>
The organic polyisocyanate used in the present invention contains at least one selected from the group consisting of diphenylmethane diisocyanate, polymethylene polyphenyl polyisocyanate and modified products thereof (hereinafter also referred to as MDI isocyanate), of which polymethylene polyphenyl poly It is an organic polyisocyanate that essentially contains an isocyanate.
The diphenylmethane diisocyanate may be any of 2,2'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate, and any mixture thereof.
Polymethylene polyphenyl polyisocyanate is a polynuclear condensate of diphenylmethane diisocyanate and is represented by the following general formula (1).

(In the formula, n represents an integer of 1 or more, preferably an integer of 1 to 5.)
Polymethylene polyphenyl polyisocyanate, sometimes referred to as polymeric diphenylmethane diisocyanate (polymeric MDI), diphenylmethane diisocyanate (monomeric MDI ) may be a mixture.
Examples of modified diphenylmethane diisocyanate include those obtained by modifying a part of the isocyanate group with biuret, allophanate, carbodiimide, oxazolidone, amide, imide, isocyanurate, uretdione and the like.
Among these, from the viewpoint of increasing lipophilicity and increasing resin strength, those containing 20 mass or more of polymethylene polyphenyl polyisocyanate relative to the total mass of MDI-based isocyanate are preferable, and those containing 30 mass or more are more preferable. It is preferable to contain 40 mass or more, and more preferable.
In addition, from the viewpoint of the viscosity of the resulting urethane prepolymer, it preferably contains 70% by mass or less of polymethylene polyphenyl polyisocyanate, more preferably 60% by mass or less, relative to the total mass of the MDI isocyanate. .

<Urethane prepolymer>
Prepolymerization is usually carried out by charging a polyol and an organic polyisocyanate into a synthesis reactor, stirring them, and reacting them at 60 to 160°C. In the present invention, the reaction equivalent ratio NCO/OH of polyol and MDI isocyanate is 1.5 to 2.0. By setting the NCO/OH ratio to 2.0 or less, the MDI monomer theoretically does not remain.
If necessary, a catalyst may be used during prepolymerization. Catalysts include amine catalysts such as triethylamine, trimethylamine, dimethylmyristylamine, stearylamine, dimethyldecylamine, N-ethylmorpholine, triethylenetetramine, tolylenediamine, xylylenediamine, monobutyltin oxide, dibutyltin oxide, tetraoctyl Tin-based catalysts such as tin, dioctyltin oxide, dibutyltin dilaurate, and dioctyltin dilaurate may also be used.
The NCO content of the urethane prepolymer is preferably 0.50-4.00% by mass, more preferably 1.50-3.50% by mass.

<Urethane injection agent>
The urethane prepolymer of the present invention has a viscosity as low as that of conventional MDI-based urethane prepolymers and forms a foamed hardening body in the presence of water. It can be suitably used as an injection agent for filling the back cavity. In addition, since the foamed hardened material can exhibit an excellent water stopping effect, it can be particularly suitably used as a water stopping agent to be injected into spring water or a water leakage point.

<Diluent>
The urethane-based injection agent of the present invention may optionally contain a diluent in order to suppress thickening during and after the reaction. The diluent preferably has a high boiling point, little odor, a high flash point and no active hydrogen. Specifically, propylene carbonate, gamma butyrolactone, vegetable oil-based fatty acid ester, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, diethylene glycol. Diethyl ether, diethylene glycol methyl ethyl ether, 2-oxo-4-methyl-1,3-dioxolane, methyl acetyl ricinoleate, butyl acetyl ricinoleate, dimethyl glutarate, dimethyl succinate, dimethyl adipate, or mixtures thereof. be done.
When a diluent is used, it is preferably used in an amount of 20 to 60% by mass based on the total mass of all components of the urethane injection agent of the present invention.

<Monoisocyanate>
Furthermore, the urethane-based injection agent of the present invention can be blended with monoisocyanate in order to improve storage stability. Monoisocyanates include octadecyl isocyanate, 3-isocyanatopropyltriethoxysilane, 3-isocyanatopropyltrimethoxysilane, p-toluenesulfonyl isocyanate (PTSI), and the like. Among them, p-toluenesulfonyl isocyanate is preferred.

<Non-MDI isocyanate>
Furthermore, the urethane-based injection agent of the present invention can be blended with a non-MDI-based isocyanate, if necessary, in order to lower the viscosity and increase the strength.
As the non-MDI isocyanate, m-xylylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane 4,4'-diisocyanate, etc. can be added. is preferred.

In addition, if necessary, additives such as foam stabilizers, defoamers, cross-linking agents, coloring agents, resin modifiers, flame retardants, ultraviolet absorbers, and durability improvers are added to the extent that the objects of the present invention are not impaired. can be added at

In the urethane-based injection agent of the present invention, the urethane prepolymer reacts with water in the presence of water to form a foamed cured product. Tertiary amines such as dimethyllaurylamine and dimethylmyristylamine can be added.

Furthermore, epoxy resin, acrylic resin (such as methyl methacrylate), styrene resin, or the like may be used in combination with the urethane-based injection agent of the present invention, depending on the construction situation. When these resins are used in combination, they can be blended in an amount of 1 to 50% by mass based on the mass of the urethane prepolymer used in the injection agent of the present invention.

The present invention will now be described with reference to examples. However, the present invention is in no way limited by these examples and comparative examples. In addition, in the present Example, the number average molecular weight was measured using GPC.
<GPC measurement conditions>
Apparatus: Tosoh HLC-8120GPC
Solvent: Tetrahydrofuran Flow rate: 0.6 ml/min
Temperature: 40°C
Sample concentration: 0.1%
Sample injection volume: 20 μl
Detector: RI

Example 1
An ethylene oxide propylene oxide block adduct of diethylene glycol as polyol A (ethylene oxide content 30% by weight based on the total weight of all alkylene oxides added, number 9.0 g of an average molecular weight of 3000), 6.0 g of a propylene oxide adduct of pentaerythritol, and 86.3 g of dipropylene glycol as a low-molecular-weight polyol were added. Next, 350 g of polymeric MDI (manufactured by BASF INOAC Polyurethane Co., Ltd., trade name "Lupranate M11S") as an isocyanate component and propylene carbonate as a diluent were added to the same apparatus, and the temperature was raised to 100° C. and reacted for 4 hours to reduce the NCO content. 11.1% urethane prepolymer was obtained.
Finally, as diluents, 40 g of castor oil fatty acid ester (manufactured by Ito Oil Co., Ltd., trade name “Ricksizer C-401”), 108 g of xylylene diisocyanate (manufactured by Mitsui Chemicals, Inc., trade name “Takenate 500”), 1.8 g of a foaming agent (manufactured by Dow Toray Industries, Inc., trade name "VORASURF L-5340") and 3 g of p-toluenesulfonyl isocyanate (manufactured by VanDeMark Chemical Inc.) were added to obtain the urethane injection agent 1 of the present invention. rice field.

Examples 2-12, Comparative Examples 1-5
A sample liquid of a urethane-based injection agent was obtained in the same manner as in Example 1, except that the types and blending amounts of polyol A, polyol B, low-molecular-weight polyol, isocyanate, and diluent were changed as shown in Table 3. In addition, the abbreviation of each raw material in Table 3 is as follows.

<Low-molecular-weight polyol>
・DPG: dipropylene glycol ・PG: propylene glycol ・DEG: diethylene glycol ・EG: ethylene glycol ・1,4′-BG: 1,4′-butanediol <MDI isocyanate>
・Polymeric MDI: polymethylene polyphenylene polyisocyanate (manufactured by BASF INOAC Polyurethane Co., Ltd., trade names “Lupranate M20S”, “Lupranate M11S”, “Lupranate M5S”)
- Mixed MDI: a mixture of 4,4'-MDI and 2,4'-MDI (2,4'-diphenylmethane diisocyanate) (trade name "Millionate NM" manufactured by Tosoh Corporation)
・2,4′-MDI: 2,4′-diphenylmethane diisocyanate (manufactured by Sigma-Aldrich Japan)
<Diluent>
・GBL: gamma butyl lactone ・PC: propylene carbonate ・C-401: castor oil fatty acid ester (trade name “Ricksizer C-401” manufactured by Ito Oil Co., Ltd.)
<Non-MDI isocyanate>
・XDI: Xylylene diisocyanate (trade name “Takenate 500” manufactured by Mitsui Chemicals, Inc.)
<Silicone foam stabilizer>
・ L-5340: Silicone foam stabilizer (trade name “VORASURF L-5340” manufactured by Dow Toray Industries, Inc.)
<Monoisocyanate>
・PTSI: p-toluenesulfonyl isocyanate

[Performance evaluation]
The urethane injection agents obtained in Examples 1 to 12 and Comparative Examples 1 to 5 were subjected to the following performance evaluation tests (1) to (10). Table 3 shows the results.

(1) Viscosity measurement Based on JISK1557-5:2007 Plastics - polyurethane raw material polyol test method, No. Brookfield viscometer (Brookfield) was used. 2 and No. 3 was rotated at 30 to 60 rpm, and the viscosity of each sample liquid at 20°C was measured.
(2) NCO content Measured based on the JISK1603-1:2007 plastic-polyurethane raw material aromatic isocyanate test.
(3) 4,4'-MDI monomer residual amount Using a liquid chromatograph HPLC-prominence (manufactured by Shimadzu Corporation) and a column Develosil C30-UG 5 μm (manufactured by Nomura Chemical Co., Ltd.), THF: water = 4: 6 calibration curve was prepared to measure the residual amount of 4,4'-MDI monomer contained in each sample liquid.
(4) Appearance of sample It was visually confirmed that the sample liquid was transparent with no turbidity or impurities.
(5) Product Stability The viscosity of each sample liquid at 20° C. after standing at 70° C. for 7 days was measured according to the measuring method (1).
(6) Curing time 30 g of the sample solution temperature-controlled at 20°C is added to a plastic cup, 0.3 g of dimethylmyristylamine is added thereto, and the mixture is stirred with a spatula for 10 seconds. Further, 3 g of water temperature-controlled at 20° C. is added and stirred for 10 seconds. The time at which the mixed solution foamed and hardened and began to draw threads was measured and defined as "hardening time".
(7) Asker C hardness The Asker C hardness of the cured resin obtained in the above test (6) was measured based on JIS K7312 "Methods for physical testing of thermosetting polyurethane elastomer moldings".
(8) Expansion Ratio Each sample liquid was foamed and cured, and the expanded volume was compared with the undiluted liquid.
(9) Shrinkage ratio The shrinkage ratio of the cured resin obtained in the above test (6) after 24 hours of curing was measured by comparing with the volume after 30 minutes of curing.
(10) Permeability Coefficient The permeability coefficient of the cured resin obtained in the above test (6) was measured according to JIS A1218 (2009) "Method for testing soil permeability".

As shown in Table 3, the urethane-based injection agent according to the present invention was found to be excellent in all of the properties (1) to (10).
On the other hand, in various comparative examples, the strength was insufficient due to the absence of polymethylene polyphenyl polyisocyanate (Comparative Examples 1 and 3), and the excessive amount of organic polyisocyanate resulted in poor polyol balance and poor foamability, and cell collapse and the like. Low foaming (Comparative Examples 2 and 3), excess 4,4'-MDI monomer remaining (Comparative Examples 2 and 4) due to NCO/OH being greater than 2.0, NCO/OH without addition of low-molecular-weight polyol Due to the design in which OH was 2.0, there were problems such as high viscosity and poor long-term storage stability (Comparative Example 5). Furthermore, for the above reason, except for Comparative Example 5 in which cell foaming was relatively stable, all the samples had a higher water permeability coefficient than those of Examples, and sufficient water stopping performance cannot be expected.

Claims (10)

a polyol and at least one organic polyisocyanate selected from the group consisting of diphenylmethane diisocyanate, polymethylene polyphenyl polyisocyanate and modified products thereof;
A urethane injection agent mainly composed of a urethane prepolymer having a terminal isocyanate group obtained by reacting such that the equivalent ratio (NCO/OH) of the isocyanate group and the hydroxy group is 1.5 to 2.0. ,
The polyol is a polyol A having a number average molecular weight of 800 or more and 7,000 or less obtained by addition polymerization of ethylene oxide alone or ethylene oxide and alkylene oxide having 3 or 4 carbon atoms to a polyhydric alcohol;
Polyol B having a number average molecular weight of 300 or more and 5,000 or less, obtained by addition polymerization of propylene oxide alone or ethylene oxide and propylene oxide to a polyhydric alcohol or polyhydric phenol at a ratio of 80% by mass or more of propylene oxide. When,
a bifunctional low-molecular-weight polyol having a number average molecular weight of less than 300,
The organic polyisocyanate contains polymethylene polyphenyl polyisocyanate,
Urethane injection. The urethane-based injection agent according to claim 1, wherein the organic polyisocyanate contains 20 to 70% by mass of polymethylene polyphenyl polyisocyanate. 3. The urethane-based injection agent according to claim 1, wherein the residual unreacted 4,4'-diphenylmethane diisocyanate is 5% by mass or less. The polyol A is at least one polyhydric alcohol selected from the group consisting of ethylene glycol, propylene glycol, diethylene glycol, and dipropylene glycol, and ethylene oxide alone or ethylene oxide and an alkylene oxide having 3 or 4 carbon atoms added thereto. The urethane-based injection agent according to any one of claims 1 to 3, which is polymerized. The polyol B is at least one polyhydric alcohol or polyhydric phenol selected from the group consisting of glycerin, diglycerin, pentaerythritol, trimethylolpropane, sorbitol, and bisphenol A, and propylene oxide alone or in combination with ethylene oxide. The urethane-based injection agent according to any one of claims 1 to 4, which is obtained by addition-polymerizing propylene oxide and propylene oxide at a rate of 80 mass% or more of propylene oxide. Claims 1 to 1, wherein the low-molecular-weight polyol is at least one selected from the group consisting of ethylene glycol, propylene glycol, diethylene glycol, 1,3-propanediol, and 1,4-butanediol. 6. The urethane-based injection agent according to any one of 5. The urethane injection agent according to any one of claims 1 to 6, further comprising a diluent. The diluent is propylene carbonate, gamma butyl lactone, vegetable oil fatty acid ester, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, triethylene glycol butyl methyl ether, 2-oxo-4-methyl-1,3-dioxolane, dimethyl glutarate, 8. The urethane injection agent according to claim 7, which is at least one selected from the group consisting of dimethyl succinate and dimethyl adipate. The urethane injection agent according to any one of claims 1 to 8, further comprising a monoisocyanate. The urethane injection agent according to any one of claims 1 to 9, further comprising a curing accelerator.