JP5561658B2 - Polyurethane resin-forming composition and steel sheet pile waterproofing material - Google Patents

Description

  The present invention relates to a water-swellable waterstop material. More specifically, the present invention relates to a polyurethane resin-forming composition used for a water-swellable water-stopping material having good curability, water-swelling property, water-stopping property, heat resistance and easy handling properties.

  Moisture-curing water-expandable water-stopping materials that are used in a single solution or with the addition of a catalyst are widely used as jointing materials for civil engineering and construction, caulking materials, and steel sheet piles for water-stopping purposes. It is used.

For example, a water-proof material for steel sheet piles including polyurethane short fibers having specific properties and having an isocyanate-terminated polyurethane prepolymer as a main component is disclosed (Patent Document 1). According to this technique, it can be applied without dripping in vertical wall surface application.
However, because this technology uses urea bonds, which are inferior in hydrolysis resistance during heating, as the main crosslinking method, the resin deteriorates due to frictional heat generated during the driving of steel sheet piles, resulting in a decrease in water stoppage. There is a problem of doing.

Further, a water-swelling water-stopping agent comprising a main component having a terminal isocyanate group-containing urethane prepolymer obtained from a polyol and an aliphatic polyisocyanate as essential components, and a curing agent having polytetramethylene glycol and an aromatic amine as essential components. Is disclosed (Patent Document 2). According to this technique, it is rich in alkali resistance and is said to be durable even when buried in the ground.
However, the combination of an aromatic isocyanate and an aromatic amine curing agent by this technique is not practical because the pot life is very short, and the isocyanate used is limited to aliphatic isocyanate. And since aliphatic isocyanate reacts slowly compared with aromatic isocyanate, there exists a problem that synthesis time becomes long and manufacture cannot be performed efficiently.

Further, a caulking material mainly composed of a water-swellable polyurethane material obtained by reacting a specific polyether polyol and polyisocyanate is disclosed (Patent Document 3). According to this technique, it is said that it is excellent in waterproofness.
However, this technique has problems in heat resistance and water resistance.

JP 2006-307035 A JP 2001-247642 A Japanese Patent Publication No.53-38750

  An object of the present invention is to provide a polyurethane resin-forming composition having good curability, water-swelling property, water-stopping property, heat resistance and easy handling when used as a water-swellable water-stopping material, and the polyurethane resin-forming property. It is providing the water-stop material for steel sheet piles using a composition.

The inventors of the present invention have arrived at the present invention as a result of intensive studies to solve the above-described problems of conventional water-swelling water-stopping materials.
That is, the present invention is described in (1) to ( 5 ) below.
(1) Isocyanate group-terminated prepolymer (A) having an isocyanate group content of 0.5 to 15% by mass and an amine-based polyol having a nominal average functional group number of 3 to 6 and a hydroxyl value of 250 to 1,200. (B) is a polyurethane resin-forming composition obtained by reacting (B) with an isocyanate group: hydroxyl group = 2: 1 to 8: 1 to obtain a polyurethane resin,
The polyurethane resin-forming composition, wherein the isocyanate group-terminated prepolymer (A) comprises an organic polyisocyanate (a1) and a polyether polyol (a2) having an oxyethylene group content of 50 to 100% by mass. .
(2) The polyether polyol (a2) is one of a polyether polyol (a2-1) having a nominal average functional group number of 2 and a polyether polyol (a2-2) having a nominal average functional group number of 3. A polyurethane resin-forming composition characterized by being one or both.
( 3 ) The polyurethane resin-forming composition, wherein the polyether polyol (a2) has a number average molecular weight in the range of 200 to 8,000.
( 4 ) The polyurethane resin-forming composition, wherein the isocyanate group-terminated prepolymer (A) contains a plasticizer (C).
( 5 ) A water-proof material for steel sheet piles using the polyurethane resin-forming composition.

According to the present invention, it is possible to obtain a polyurethane resin-forming composition having good curability, water expansion property, water-stopping property, heat resistance and easy handleability when used for a water-swellable water-stopping material.
Further, according to the present invention, it is possible to obtain a water-proof material for steel sheet piles that is sufficiently durable even when frictional heat is applied during the driving operation.

FIG. 1 is a diagram for explaining a water-stop test method.

  The isocyanate group-terminated prepolymer (A) used in the present embodiment is composed of an organic polyisocyanate (a1) and one or more polyether polyols (a2) having an oxyethylene group content of 50 to 100% by mass. The isocyanate group content is 0.5 to 15% by mass.

A known polyisocyanate can be used as the polyisocyanate (a1) used in the urethane prepolymer. Specifically, for example, known 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate (hereinafter, tolylene diisocyanate is abbreviated as TDI), xylene-1,4-diisocyanate, xylene-1,3- Diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, 2,2'-diphenylmethane diisocyanate, 4,4'-diphenylether diisocyanate, polymethylene polyphenylene polyisocyanate (hereinafter "polymeric MDI") ”, 2-nitrodiphenyl-4,4′-diisocyanate, 2,2′-diphenylpropane-4,4′-diisocyanate, 3,3′-dimethyldiphenylmethane-4,4′-diisocyanate, 4,4 '-Diphenylpropane Aromatic diisocyanates such as isocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, naphthylene-1,4-diisocyanate, naphthylene-1,5-diisocyanate, 3,3′-dimethoxydiphenyl-4,4′-diisocyanate, tetramethylene Aliphatic diisocyanates such as diisocyanate, hexamethylene diisocyanate, 3-methyl-1,5-pentane diisocyanate, lysine diisocyanate, isophorone diisocyanate, hydrogenated tolylene diisocyanate, hydrogenated xylene diisocyanate, hydrogenated diphenylmethane diisocyanate, tetramethylxylene diisocyanate, etc. Alicyclic diisocyanates, their polymers and their polymers, and mixtures of two or more of these Compound may be mentioned. Among these, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4'-difelmethane diisocyanate, 2,4'-difelmethane diisocyanate, and mixtures thereof have a high reaction rate, and It is preferable because of good physical properties.

The polyether polyol (a2) used for the urethane prepolymer (A) is a polyether polyol having a polyoxyalkylene chain in which the proportion of oxyethylene groups is 50 to 100%. Thereby, it is possible to obtain an isocyanate group-terminated prepolymer having excellent hydrophilicity. When the ratio of the polyoxyethylene group is less than 50%, there is a problem that sufficient water expandability cannot be obtained.
The polyether polyol (a2) is preferably represented by the general formula R [— (OR ¹ ) nOH] _P (where R is a polyhydric alcohol residue, (OR ¹ ) is an oxyethylene group and 3 to 4 carbon atoms. A polyoxyalkylene chain composed of an alkylene group (provided that the proportion of the oxyethylene chain occupies 50 to 100% of the weight of the polyalkylene chain), n is a number indicating the degree of polymerization of the oxyalkylene group, and the number average molecular weight is 200 to 8 1 or 2 or more of polyether polyols represented by the following formula:

  Examples of the polyhydric alcohols include dihydric alcohols (ethylene glycol, propylene alcohol, etc.), trihydric alcohols (glycerin, trimethylolpropane, etc.), tetrahydric alcohols (erythritol, pentaerythritol, etc.), pentahydric alcohols (Arbat, xylit, etc.) Etc.), hexahydric alcohols (Sorbit, Mannich, etc.).

  The polyether polyol (a2) contains a polyether polyol (a2-1) having a nominal average functional group number of 2 and an oxyethylene group content of 50 to 100% by mass, and a nominal average functional group number of 3 It is preferable from the viewpoint that it is easy to balance the viscosity and the crosslinking density that the amount is composed of one or both of the polyether polyol (a2-2) composed of 50 to 100% by mass.

  The ratio of the polyether polyol (a2-1) and the polyether polyol (a2-2) used is not particularly limited, but (a2-1) :( a2-2) = 2: 1 to 40: 1 is preferable. When (a2-2) is less than 40: 1, the crosslinking density is lowered, so that the strength is easily lowered. When it is more than 2: 1, the viscosity is increased and workability is liable to be deteriorated.

  The isocyanate group-terminated prepolymer (A) used in the present embodiment is obtained from a reaction between an excess molar ratio of the polyisocyanate (a1) and the polyether polyol (a2) with respect to the polyether polyol (a2). The NCO group content of the prepolymer is preferably from 0.5 to 15%, more preferably from 1.0% to 5%. If the isocyanate group content is less than 0.5% by mass, there is a problem that the molecular weight becomes too high and the viscosity becomes high. If it exceeds 15% by mass, the amount of carbon dioxide generated when reacting with moisture in the air is large. Therefore, there is a problem that air bubbles increase in the water stop material obtained after curing.

  In the isocyanate group-terminated prepolymer (A) used in the present embodiment, known stabilizers, additives and the like can be further added as desired as long as the object of the present invention is not impaired.

As the amine-based polyol (B) used in the present embodiment, a polyamine polyol to which an alkylene oxide is added using an amino group as an initiator can be used. Examples of the amino group used for the initiator include aliphatic amines such as ammonia, ethylenediamine, hexamethylenediamine, isophoronediamine and diethylenetriamine, and aromatic amines such as tolylenediamine and diphenylaminomethane. Among these polyamine polyols, amine polyols having a highly basic aliphatic amine as an initiator are preferred in that the curing time can be shortened.

  The number of functional groups of the amine polyol (B) is 3-6. If the number of functional groups is less than 3, the strength, heat resistance, and consequently water-stop properties of the water-stopping material are likely to be adversely affected. When the number of functional groups is larger than 6, the viscosity becomes high and handling is difficult.

  The hydroxyl value of the amine polyol (B) is preferably 250 to 1,200 KOHmg / g. When the hydroxyl value is less than 250 KOH mg / g, the blending amount increases, and further, the distance between the cross-linking points increases, so that the strength, heat resistance, and eventually water-stopping property of the water-stopping material are liable to be adversely affected. When the molecular weight is larger than 1,200 KOHmg / g, the molecular weight becomes small, so that it tends to volatilize and a problem with odor is likely to occur.

  In the present embodiment, the ratio of the isocyanate group-terminated prepolymer (A) and the amine-based polyol (B) is such that the molar ratio of isocyanate group to hydroxyl group is isocyanate group: hydroxyl = 2: 1 to 8: 1. If there are more hydroxyl groups than 2: 1, there will be an increase in the number of urethane bonds that have a lower cohesive strength than the urea bonds that form when they react with moisture in the air, which will adversely affect the strength, heat resistance, and thus water-stop properties of the water-stopping material. It is easy. When the number of hydroxyl groups is less than 8: 1, the crosslinking by the amine-based polyol (B) is reduced, so that the strength, heat resistance, and consequently the water-stopping property of the water-stopping material are liable to be adversely affected.

  The plasticizer (C) that can be used in the present embodiment may be any known plasticizer, such as dimethyl phthalate, diethyl phthalate, dibutyl phthalate, dihexyl phthalate, di-2-ethylhexyl phthalate, phthalate. Diisononyl acid, diisodecyl phthalate, butyl benzyl phthalate, diethyl adipate, dibutyl adipate, dihexyl adipate, diethylhexyl adipate, diisononyl adipate, diisodecyl adipate, bis (butyldiglycol) adipate, diethyl sebacate, Dibutyl sebacate, dihexyl sebacate, di-2-ethylhexyl sebacate, dimethyl maleate, diethyl maleate, dibutyl maleate, dihexyl maleate, di-2-ethylhexyl maleate, diisononyl maleate, dii maleate Ester compounds such as decyl, phosphate compounds such as tributyl phosphate, tri-2-ethylhexyl phosphate, triphenyl phosphate, tricresyl phosphate, 1-phenyl-1-xylylethane, 1-phenyl-1-ethylphenylethane There are those such as aromatic hydrocarbon compounds, and it is possible to use one or more of them in combination. Of these, 1-phenyl-1-xylylethane and 1-phenyl-1-ethylphenylethane are preferred because of their good hydrolysis resistance.

  The ratio of the isocyanate group-terminated prepolymer (A) and the plasticizer (C) is not particularly limited, but preferably the amount of the plasticizer (C) does not exceed the weight of the isocyanate group-terminated prepolymer (A). That is good. Moreover, you may add a plasticizer (C) to amine type polyol (B) in order to adjust the compounding ratio of isocyanate group terminal prepolymer (A) and amine type polyol (B).

The polyurethane sheet-forming composition of the present embodiment is used for the water-proof material for steel sheet piles of the present embodiment.
By applying the water-stopping material for steel sheet piles to the steel sheet pile, the durability is sufficient even if frictional heat is applied during the driving operation.

[Synthesis Example 1]
A reactor equipped with a stirrer, a cooling pipe, a nitrogen introducing pipe, and a thermometer was purged with nitrogen, and then 65.8 g of TDI (trade name “T-80”, manufactured by Nippon Polyurethane Industry Co., Ltd.) was added to the reactor. 229 g of an agent (manufactured by Nippon Oil Corporation, trade name “Nisseki Hysol SAS-296”) was charged. Next, 564 g of the following polyol A and 141 g of the following polyol B were charged while stirring at room temperature and reacted for 15 hours while stirring at 80 ° C. to 90 ° C. to give an isocyanate (NCO) content of 1.5% and a viscosity at 25 ° C. of 2, An isocyanate-terminated prepolymer “P1” of 700 mPa · s was obtained.
Polyol A: PB-5064 manufactured by Toho Chemical Industry, ethylene oxide (EO) / propylene oxide (PO) adduct, EO / PO (molar ratio) = 70/30, hydroxyl value = 22, initiator functional group = 2
Polyol B: GRB-2543 manufactured by Toho Chemical Industry, ethylene oxide (EO) / propylene oxide (PO) adduct, EO / PO (molar ratio) = 50/50, hydroxyl value = 72, initiator functional group = 3

[Synthesis Example 2]
A reactor equipped with a stirrer, a cooling pipe, a nitrogen introduction pipe, and a thermometer was purged with nitrogen, and then 60.0 g of TDI (trade name “T-80”, manufactured by Nippon Polyurethane Industry Co., Ltd.) was added to the reactor. 229 g of an agent (manufactured by Nippon Oil Corporation, trade name “Nisseki Hysol SAS-296”) was charged. Next, 646 g of the polyol A of Synthesis Example 1 and 65 g of the polyol B of Synthesis Example 1 were charged with stirring at room temperature and reacted at 80 ° C. to 90 ° C. for 15 hours to obtain an isocyanate (NCO) content of 1.5%, 25 An isocyanate-terminated prepolymer “P2” having a viscosity at 2500 ° C. of 2,500 mPa · s was obtained.

[Example of adjustment]
Curing agents “H1” to “H13” were prepared by mixing and stirring the components at a blending ratio shown in Table 1 until they were uniform at room temperature.

<Raw material>
Triethanolamine: f = 3, manufactured by Tokyo Chemical Industry New Pole NP-300: manufactured by Sanyo Chemical Industries, PO addition product of ethylenediamine, f = 4, OHv = 760
Newpol NP-400: PO adduct of diethylenetriamine manufactured by Sanyo Chemical Industries, f = 5, OHv = 693
EDP-1100: Made by Adeka, PO addition product of ethylenediamine, f = 4, OHv = 220
N-methyldiethanolamine: f = 2, manufactured by Tokyo Chemical Industry Sannix HS-209: manufactured by Sanyo Chemical Industries, shoe-closed PO adduct, f = 5, OHv = 450
Etacure 100: Diethyltoluenediamine manufactured by Albemarle, f = 2, amine value 630
Kao Riser No. 300: imidazole catalyst manufactured by Kao Corporation DIDP: diisodecyl phthalate, manufactured by Daihachi Chemical Co., Ltd.

[Test method of tensile strength after water swelling (room temperature curing)]
After mixing the curing agent in the amount shown in Table 2 below with the main agent, pour it into a plastic tray placed on a horizontal table so that the thickness is 2 mm, and leave it at room temperature for 48 hours to obtain a cured film. It was. After immersing this film in ion exchange water for 24 hours, the tensile strength of a test piece punched out with a JIS No. 2 dumbbell was measured.

[Test method for tensile strength after water swelling (after heat abuse)]
After mixing the curing agent in the amount shown in Table 2 with the main agent, it was poured into a plastic tray placed on a horizontal table so as to have a thickness of 2 mm, and allowed to stand at room temperature for 48 hours to obtain a cured film. . This film was placed in a dryer heated to 180 ° C. for 20 minutes and heated. Next, after immersing in ion exchange water for 24 hours, the tensile strength of the test piece punched out with a JIS No. 2 dumbbell was measured. A tensile strength of 3N or more is good.

[Waterproof test method]
After mixing the hardening agent with the amount of the main agent in the amount shown in Table 2, the two white line parts (gap gap between the gaps 2mm) in the angle meshing part of the steel sheet pile test piece shown in FIG. Poured and left at room temperature for 48 hours to obtain a steel sheet pile test piece (before heating) coated with a water stop material. Further, the steel sheet pile test piece obtained in the same manner was placed in a dryer heated to 180 ° C. for 20 minutes and heated to obtain a steel sheet pile test piece (after heating). The test piece was sandwiched between two plates as shown in FIG. 1, filled with water and immersed for 24 hours to swell. Then, the presence or absence of water leakage was confirmed by applying a water pressure of 0.5 MPa with a pressure pump from the water inlet (hexagonal portion) of the upper plate. Those with no water leakage were accepted, and those with water leakage were rejected.

[Pot life]
The main agent and the curing agent are blended at the blending ratio shown in Table 2, and the viscosity (after removing the cured film on the surface) after standing at 25 ° C. for 3 hours is 50 Pa · s at 25 ° C. or less.

Claims (6)

Isocyanate group-containing prepolymer (A) having an isocyanate group content of 0.5 to 15% by mass and an amine-based polyol (B) having a nominal average functional group number of 3 to 6 and a hydroxyl value of 250 to 1,200 And a polyurethane resin-forming composition that obtains a polyurethane resin by reacting with an isocyanate group: hydroxyl group = 2: 1 to 8: 1.
A polyurethane resin-forming composition, wherein the isocyanate group-terminated prepolymer (A) comprises an organic polyisocyanate (a1) and a polyether polyol (a2) having an oxyethylene group content of 50 to 100% by mass. The polyether polyol (a2) is one or both of a polyether polyol (a2-1) having a nominal average functional group number of 2 and a polyether polyol (a2-2) having a nominal average functional group number of 3 The polyurethane resin-forming composition according to claim 1, wherein   2. The polyurethane resin-forming composition according to claim 1, wherein the polyether polyol (a2) has a number average molecular weight in the range of 200 to 8,000. The polyurethane resin-forming composition according to any one of claims 1 to 3 , wherein the isocyanate group-terminated prepolymer (A) contains a plasticizer (C). A waterstop material for steel sheet piles using the polyurethane resin-forming composition according to any one of claims 1 to 3 . A waterstop material for steel sheet piles using the polyurethane resin-forming composition according to claim 4 .

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