JPH0489B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a moisture-curable urethane prepolymer (hereinafter referred to as urethane composition).
More specifically, the present invention relates to a method for producing a moisture-curable composition that is moisture-cured to provide a cured product having excellent water-swelling and water-stopping properties (the production method will be explained below with a description of the composition). Conventionally, moisture-curable NCO-terminated urethane prepolymers with water-swelling properties have been used as caulking or water-stopping materials by combining bifunctional and trifunctional polyoxypropylene oxyethylene polyether polyols and polyisocyanates such as tolylene diisocyanate. It is known to be used (Tokuko Sho 53)
-38750). However, the swelling rate of this prepolymer was small, ranging from 0.1 to 4.8 times its own weight, and it could not be used as a caulking or water-stopping material for gap-filling, which requires a large swelling rate (5 to 20 times). . Also, base resistance [base (caustic soda,
It had poor hydrolysis resistance in aqueous solutions (ammonia, organic amines, etc.) and could not withstand use in basic water. In order to solve the above-mentioned problems, the present inventors have made repeated studies and have arrived at the present invention. That is, the present invention is characterized by comprising an NCO-terminated urethane prepolymer A having a urethane bond bonded to an aliphatic group (however, the aliphatic group is bonded to NH of the urethane bond) and an NCO group bonded to an aromatic nucleus. This is a method for producing a moisture-curable urethane composition that provides a cured product with water-stopping properties. In the present invention, the NCO-terminated urethane prepolymer A includes an NCO-terminated urethane prepolymer of an OH-terminated urethane prepolymer a made of an aliphatic polyisocyanate and an excess polyether polyol and an aromatic polyisocyanate. In the present invention, the aliphatic polyisocyanate that provides urethane bonds bonded to aliphatic groups is a polyisocyanate in which all NCO groups are bonded to non-aromatic hydrocarbon atoms. (excluding carbon) aliphatic polyisocyanates having 2 to 12 carbon atoms, cycloaliphatic polyisocyanates having 4 to 15 carbon atoms, araliphatic (aliphatic having an aromatic nucleus) polyisocyanates having 8 to 12 carbon atoms, and these polyisocyanates. Variants (carbodiimide groups, uretdione groups, uretimine groups, urea groups, Biuret groups and/or isocyanurate groups, modified products containing etc.) can be used. Such polyisocyanates include ethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate (HDI),
Dodecamethylene diisocyanate, 1,6,11-
Undecane triisocyanate, 2,2,4-trimethylhexane diisocyanate, lysine diisocyanate, 2,6-diisocyanate methyl caproate, bis(2-isocyanate ethyl) fumarate, bis(2-isocyanate ethyl) carbonate, 2-isocyanate ethyl-
2,6-diisocyanate hexanoate; isophorone diisocyanate (IPDI), dicyclohexylmethane diisocyanate (hydrogenated MDI), cyclohexylene diisocyanate, methylcyclohexylene diisocyanate (hydrogenated TDI), bis(2-isocyanate ethyl) 4-cyclohexene-1 , 2-dicarboxylate; xylene diisocyanate, diethylbenzene diisocyanate; water-modified products of HDI, trimerized products of IPDI, etc.; and mixtures of two or more thereof. Preferred among these are HDI.IPDI and hydrogenated
It is MDI. Examples of polyether polyols include low-molecular polyols (bifunctional polyols such as ethylene glycol, propylene glycol, 1,4-butanediol, diethylene glycol, and cyclohexylene glycol; trifunctional polyols such as glycerin, trimethylolpropane, pentaerythritol, sorbitol, and seurose (e.g. polyols with higher functionality)
Polyhydric phenols (bisphenols such as bisphenol A) or/and amines (alkanolamines such as triethanolamine, N-methyldiethanolamine, aliphatic polyamines such as ethylenediamine, diethylenetriamine, aromatic diamines such as tolylenediamine, diphenyl) alkylene oxide (alkylene oxide having 2 to 4 carbon atoms, such as ethylene oxide (also referred to as EO),
One or more (random and/or block) adducts of propylene oxide (also referred to as PO), butylene oxide, etc., ring-opening polymers of alkylene oxides (ring-opening polymerization of tetrahydrofuran, polytetramethylene produced by hydrolysis) ether glycol, etc.). The average hydroxyl equivalent of the polyether polyol is usually 800 to 4,000, preferably 1,000 to 3,000. If the average hydroxyl equivalent is less than 800, the swelling rate will be insufficient,
If it exceeds 4,000, shape retention and pressure resistance when swollen with water decrease, both of which may cause water leakage. Among the polyether polyols, preferred are ethylene oxide adducts (polyoxyethylene polyols) of di-trihydric alcohols (especially ethylene glycol, propylene glycol and glycerin) and/or adducts of ethylene oxide and propylene oxide (random and/or
or block adduct) [oxyethylene/oxypropylene copolymer polyether polyol (copolymer polyether polyol)], and particularly preferred is copolymer polyether polyol. In polyether polyol a, the oxyethylene content is in the total weight of all oxyalkylenes,
Preferably 50-100%, particularly preferably 60-85
%. If the oxyethylene content is less than 50%, the water swelling rate will be insufficient and cause water leakage. In addition to polyoxyethylene polyols and/or copolymerized polyether polyols, other polyether polyols such as polyoxypropylene polyols can also be preferably used together with the polyether polyols, but in this case, the oxyethylene content in the combined product is 50 to 100 in the total weight of all oxyalkylenes as above
%, particularly preferably 60 to 85%. In the OH-terminated urethane prepolymer a made from aliphatic polyisocyanate and excess polyether polyol, the NCO/OH ratio of aliphatic polyisocyanate and polyether polyol is usually 1/1.2 to 1/8, preferably 1/1.5. When the NCO/OH ratio exceeds 1/1.2, which is 1/4, the OH-terminated urethane prepolymer becomes highly viscous and becomes difficult to handle in practice. Also, the NCO/OH ratio is 1/
When it is less than 8, base resistance decreases. The OH-terminated urethane prepolymer a can be obtained by reacting an aliphatic polyisocyanate and a polyether polyol at the above NCO/OH ratio in a conventional manner. The reaction temperature is usually
The temperature is 60 to 130°C, preferably 70 to 120°C, and the reaction time is usually 4 to 20 hours, preferably 6 to 15 hours. The prepolymerization reaction can also be carried out in a solvent depending on the case. Examples of this solvent include polar solvents that do not have active hydrogen, such as ketone solvents (methyl ethyl ketone, methyl isobutyl ketone, etc.), ester solvents (methyl acetate, ethyl acetate, etc.),
Examples include etherified or esterified cellosolve solvents (dimethyl cellosolve, methyl cellosolve acetate, etc.) and mixtures of two or more thereof. The weight of the commonly used solvent is
The amount is usually 0 to 120 parts by weight, preferably 10 to 80 parts by weight, per 100 parts by weight of the OH-terminated urethane prepolymer. Further, the prepolymerization reaction can be carried out in the presence of a catalyst depending on the case. This catalyst is generally a conventionally known catalyst that promotes the reaction between an isocyanate group and an active hydrogen compound, such as an organometallic catalyst (dibutyltin dilaurate, lead octylate, stannath octoate, etc.) and/or a tertiary amine compound (triethylamine, triethylenediamine, etc.) can be used. The average hydroxyl equivalent of the obtained OH-terminated urethane prepolymer a is usually 900 to 25,000, preferably 1,300.
~9300. In the present invention, the aromatic polyisocyanates that provide the terminal NCO bonded to the aromatic nucleus of the NCO-terminated urethane prepolymer A include tolylene diisocyanate (hereinafter referred to as TDI) and 4,4'-diphenylmethane diisocyanate (hereinafter referred to as MDI). , crude MDI, modified MDI [for example, MDI modified to contain a carbodiimide group, uretdione group, or uretone imine group (Japanese Patent Publication No. 1983-
27098] and these two
Examples include mixtures of more than one species. Preferred among these are TDI and MDI. In the present invention, in the NCO-terminated urethane prepolymer A of OH-terminated urethane prepolymer a and aromatic polyisocyanate, OH-terminated urethane prepolymer a and aromatic polyisocyanate are
The NCO/OH ratio is usually 1.4/1 to 3/1, preferably 1.6/1 to 2.5/1. NCO/OH ratio is 1.4/
If it is less than 1, the shape retention and pressure resistance upon swelling with water will be reduced, and if it exceeds 3/1, the swelling ratio will be insufficient and both will cause water leakage. NCO-terminated urethane prepolymer A can be obtained by reacting OH-terminated urethane prepolymer a and aromatic polyisocyanate at the above NCO/OH ratio. The reaction temperature is usually 60~
The temperature is 100°C, preferably 70-90°C, and the reaction time is usually 4-12 hours, preferably 6-10 hours. The reaction to obtain this NCO-terminated urethane prepolymer A can optionally be carried out in the presence of a solvent and/or a catalyst, as in the case of obtaining the OH-terminated urethane prepolymer a, and the preferred solvent and its amount are also the same, The same applies to preferred catalysts. The obtained NCO-terminated urethane prepolymer A
NCO% is usually 0.05-7%, preferably 0.1%-4
%. The molar ratio of aliphatic polyisocyanate to aromatic polyisocyanate in the total polyisocyanate used to obtain NCO-terminated urethane prepolymer A is usually 1:0.7 to 20, preferably 1:0.8.
~9. The concentration of urethane bonds bonded to aliphatic groups in NCO urethane prepolymer A (in the composition excluding the solvent if a solvent is used) is usually 2.5 × 10 ^-5 mol/g ~
1.0×10 ^-3 mol/g, preferably 7.0×10 ^-5 mol/g
~6.5×10 ^-4 mol/g, and the concentration of aromatic-bonded urethane bonds is typically 5.5×10 ^-5 mol/g ~3.0×
10 ^-3 mol/g, preferably 1.5×10 ^-4 mol/g to 2.0
×10 ^-3 mol/g. Examples of OH-terminated urethane prepolymer A made from aliphatic polyisocyanate and excess polyether polyol and NCO-terminated urethane prepolymer A made from this and aromatic polyisocyanate include compounds represented by the following general formula. (a): R ₁ - [OCONH-A-NHCOO-R ₁ -) _o OH] ₂ (1) R' ₁ - [OCONH-A-NHCOO-R ₁ -) _o OH] _x (2) R' ₁ -[OCONH-A-NHCOOR' ₁ -(OH) _x-1 ] _x (3) (A): R ₂ -[(OCONH-Ar-NHCOO-R ₂ -O-) _n CON
H−Ar−NCO〕 ₂ (1)′ R′ ₂ −[(OCONH−Ar−NHCOO−R ₂ −O−) _n C
ONH−Ar−NCO〕 _x (2)′ R″ ₂ −(OCONH−Ar−NCO) _y (3)′ [In the formula, R ₁ is a polyether diol residue, A is an aliphatic diisocyanate residue, Ar is an aromatic diisocyanate residue, n and m are integers of 0 or 1 or more, R ₂ , R′ ₂ , R″ ₂ are general formulas (1), (2), and
OH-terminated urethane prepolymer residue represented by (3), x is an integer of 3 or more (preferably an integer of 3 to 8), and y is an integer represented by x x (x-1)] Moisture of the present invention The curable urethane composition is composed of NCO-terminated urethane prepolymer A, but may further contain other additives such as fillers, colorants, antioxidants, plasticizers, etc. Examples of fillers include bentonite, calcium carbonate, clay, talc, and finely powdered silica; colorants include titanium white, carbon black, red iron, and chrome green; and antioxidants include hindered phenols, hindered amines, and plasticizers. Examples of the agent include dioctyl phthalate, dibutyl phthalate, and dioctyl adipate. The total weight of other compounding agents is usually 0 to 50 parts by weight, preferably 0 to 30 parts by weight, based on 100 parts of NCO-terminated urethane prepolymer A. In addition, water-insoluble water-absorbing resin (JP-A-52-
No. 149190, JP-A-51-125468, JP-A-52-
25886 and JP-A No. 52-59690, water-insoluble monomers and/or monomers A' that become water-soluble upon hydrolysis, starch and/or cellulose B' and/or crosslinking agents C' (such as a polymer obtained by polymerizing as an essential component and hydrolyzing it if necessary) can also be added. When using the composition of the present invention, it is applied to a substrate and cured with moisture on the substrate to form a cured product (urethane resin).
Alternatively, it may be poured into a mold or poured directly onto a glass plate and cured with moisture to form a molded product of urethane resin. When applied to a substrate, examples of the substrate include metal (iron, tin, galvanized iron, aluminum, etc.), concrete, mortar, wood, slate, glass, etc. When the applied substrate is metal, a primer is used if necessary. This primer is an NCO-excess urethane prepolymer obtained by reacting a polyisocyanate component with an active hydrogen component consisting of an oxyalkylene ether of bisphenols and, if necessary, a polyhydric alcohol and a polymer polyol (Japanese Patent Application No. 57-110182). No. and patent application 1983-
No. 187353) and a composition consisting of an NCO component consisting of polymethylene polyphenyl polyisocyanate, an oxyalkylene ether of bisphenols, and optionally an active hydrogen component consisting of a low-molecular polyol and a high-molecular polyol (Japanese Patent Application No. 1983) -120318, -168310 and -
168311). Among these, the former is preferred. In addition, ordinary moisture curing type
NCO urethane prepolymer [high molecular polyol (polypropylene glycol, etc.), low molecular polyol (ethylene glycol, 1,4-
butanediol, glycerin, trimethylolpropane, pentaerythritol, polypropylene glycol (molecular weight 400 or less), etc.) and polyisocyanate.
A prepolymer obtained by reacting an NCO component with an excess of NCO groups, usually having an NCO% of 3 to 15%, can also be used. The composition of the present invention can be applied to a substrate by spraying, brushing, roller coating,
Methods include applying with a spatula, applying with a caulking gun, and applying with a trowel. The amount of coating in this case is not particularly limited, but is usually 100 g/m 2 to 2000 g/m ² . Further, the film thickness is usually 10μ or more, preferably 100μ to 20mm. Curing conditions for moisture curing the composition of the present invention may vary, but are usually in the atmosphere at room temperature for 5 hours to 2 days. If necessary, conventionally known catalysts for promoting moisture curing, such as organometallic catalysts (dibutyltin dilaurate, lead octylate, stannath octoate, etc.), may also be used.
and/or tertiary amine compounds (triethylamine, triethylenediamine, etc.) may be added to speed up curing (eg, about 30 minutes). The composition of the present invention is moisture cured in the atmosphere to give a cured product (urethane resin) having excellent water swelling and water stopping properties. That is, the cured product has the property of swelling to about 5 to 10 times its own weight (500 to 2000%) when immersed in water, sea ice, hard water, metal ion-containing water, or the like. In addition, the cured product has good base resistance [hydrolysis resistance in base (loading soda, ammonia, organic amine, etc.) aqueous solutions] and can be used satisfactorily even in basic water. Furthermore, the cured product has good weather resistance, does not peel off or fall off when swollen with water, and does not lose its water swelling ability and water-stopping properties due to repeated water swelling and drying. The composition of the present invention can be used, for example, as a water-swellable coating material, a sealant, a caulking material, a sealant for electrical appliances (such as air conditioners and refrigerators), a ship,
It can be used for applications such as various joint sealing materials for vehicles, etc. The present invention will be further explained below with reference to Examples and Comparative Examples, but the present invention is not limited thereto. Parts in the examples indicate parts by weight. In addition, the swelling ratio in the examples is water absorption amount (g)/weight of the composition of the present invention before immersion (g) x
100, and the water stop test was conducted as follows. Waterstop test The composition of the present invention was applied to the inside of a steel pipe with an inner diameter of 200 mm to a thickness of 3 mm (three coats), and was cured in the atmosphere at room temperature to coat the inner surface. Attach this steel pipe to the bottom of the water tank and connect the steel pipe outlet to
After sealing the tank with a rubber stopper and filling it with water, leave it for 24 hours.
The rubber stopper at the outlet of the steel pipe was removed to test for water leakage. Examples 1, 2 Ethylene glycol EO/PO [EO/PO weight
60/40 (Example 1) 80/20 (Example 2)] OH-terminated urethane prepolymer (NCO/OH = 1/2, average hydroxyl group equivalent: 4110) of random adduct (average molecular weight: 4000) and IPDI Moisture curing NCO with MDI
Terminal urethane prepolymer (NCO/OH=2.4)
was used as the composition of the present invention. The above composition of the present invention was obtained as follows.
In other words, Table 1 of EO and PO for ethylene glycol
1000 g of polyether glycol (hereinafter referred to as polyether glycol) with an average molecular weight of 4000 obtained by adding a mixture with the EO/PO weight ratio shown in
28 g of IPDI (NCO/OH=1/2) was reacted at 120° C. for 8 hours to obtain an OH-terminated urethane prepolymer having an average hydroxyl equivalent of 4110. When we measured the infrared absorption spectrum of this product, no spectrum specific to the isocyanate group at 2200 cm ^-1 was observed.
Disappearance of the NCO group was confirmed, and the hydroxyl equivalent was measured to be 4110 using the pyridine phthalic anhydride method. Furthermore, 1028g of this OH-terminated urethane prepolymer
75 g of MDI (NCO/CH=2.4) was added and reacted at 80° C. for 5 hours to obtain a composition of the present invention having an NCO% of 1.3%. The composition of the present invention was poured onto a glass plate and cured in the atmosphere at room temperature for 24 hours to obtain a molded article of the composition of the present invention having a thickness of 2 mm. About this molded product Tap water, 3
% saline solution and 1% NaOH aqueous solution, the swelling ratio was measured after soaking for one week. Furthermore, a water stop test was conducted on the composition of the present invention, and the results are shown in Table 1.

[Table] Examples 3 and 4 OH-terminated urethane prepolymers (NCO/ OH = 1/2), 2,4-isomer, and 2,6-isomer at a mixing ratio of 80:20 (TDI
An NCO-terminated urethane prepolymer (NCO/OH=2.4) with TDI-80) was used as the composition of the present invention. The above composition of the present invention was obtained as follows.
That is, ethylene glycol EO and PO EO/
Polyether glycol (hereinafter referred to as polyether glycol) having the average molecular weight shown in Table 2 obtained by adding a mixture of 80/20 in PO weight ratio and IPDI in the ratio NCO/OH shown in Table 2
(1/2) and reacted at 120° C. for 8 hours to obtain OH-terminated urethane prepolymers having the hydroxyl group equivalents shown in Table 2. When the infrared absorption spectrum of this product was measured, no spectrum specific to the isocyanate group at 2200 cm ^-1 was observed, and the disappearance of the NCO group was confirmed, and the hydroxyl group equivalent in Example 3 was 2110, In Example 4, it was 4110. Furthermore, the proportions of this OH-terminated urethane prepolymer and TDI-80 are shown in Table 2.
The composition of the present invention was obtained by adding NCO/OH=2.4 and reacting at 80° C. for 8 hours. The above composition of the present invention was cured on a glass plate in the atmosphere at room temperature for 24 hours to obtain a molded article of the composition of the present invention having a thickness of 2 mm. The swelling ratio of this molded article was measured after being immersed in tap water, 3% saline solution, and 1% NaOH aqueous solution for one week. Furthermore, a water stop test was conducted on the composition of the present invention, and the results are shown in Table 2.

[Table] Comparative Example 4 Comparison of moisture-curable NCO-terminated urethane prepolymer (NCO/OH=1.8) of ethylene glycol EO/PO (80/20) random adduct (average molecular weight: 4000) and TDI-80 And so. The above prepolymer was obtained as follows. In other words, EO/PO of EO and PO in ethylene glycol
1000g of polyether glycol with an average molecular weight of 4000 obtained by adding a mixture of 80/20 by weight and TDI
Add 78g of −80 (NCO/OH=1.8) and heat at 80°C.
After reacting for 10 hours, a urethane prepolymer with an NCO% of 1.5% was obtained. The above prepolymer was placed on a glass plate in the atmosphere at room temperature.
A urethane resin molded product was obtained by curing for 24 hours. When this urethane resin molded article was immersed in a 1% NaOH aqueous solution, it dissolved on the second day. Comparative Example 5 Moisture-curable NCO-terminated urethane prepolymer of EO/PO (80/20) random adduct of ethylene glycol (average molecular weight: 4000) and a mixture of (IPDI and MDI) (NCO/OH ratio 2:1) . The above prepolymer was obtained as follows. In other words, the average molecular weight obtained by adding a mixture of EO and PO in a weight ratio of 80/20 to ethylene glycol.
4000 polyether glycol 1000g, isophorone diisocyanate 28g and MDI 100g NCO/OH
Add 2:1 ratio and react at 80℃ for 24 hours until the NCO%
A 2.1% urethane prepolymer was obtained. When the above prepolymer was cured in the atmosphere at room temperature, it was not completely cured within one week. Furthermore, when a water stop test was conducted on this urethane prepolymer, water leakage was observed. Example 5 EO/PO (80/20) random adduct of ethylene glycol (average molecular weight: 4000) and EO/PO (70/30) random adduct of glycerin (average molecular weight: 3600) and H-MDI (NCO/ OH=1/2.2)
OH-terminated urethane prepolymer and MDI
NCO-terminated urethane prepolymer (NCO/OH=
2) was used as the composition of the present invention. The above composition of the present invention was obtained as follows.
In other words, the average molecular weight obtained by adding a mixture of EO and PO in a weight ratio of 80/20 to ethylene glycol.
42 g of H-MDI (NCO/OH = 1/2.2) was added to 240 g of polyether triol with an average molecular weight of 3600 obtained by adding a mixture of 70/30 weight ratio of EO and PO to 1000 g of polyether glycol 4000 and glycerin.
was added and reacted at 120°C for 8 hours to obtain an OH-terminated urethane prepolymer having an average hydroxyl equivalent of 3360.
1282g of this OH-terminated urethane prepolymer
A composition of the present invention having an NCO% of 1.3% was obtained by reacting 95 g of MDI (MCO/OH=2) at 80° C. for 8 hours. The above composition of the present invention was cured on a glass plate in the atmosphere at room temperature for 24 hours to obtain a molded article of the composition of the present invention. Tap water, 3% saline solution, and 1
% NaOH aqueous solution for one week, the swelling ratios were 1050%, 1020%, and 1040%, respectively. Further, when a water stop test was conducted on the composition of the present invention, no water leakage was observed.

Claims (1)

[Claims] 1. An OH-terminated urethane prepolymer a made from an aliphatic polyisocyanate in which all NCO groups are bonded to non-aromatic hydrocarbon atoms and an excess polyether polyol, and an aromatic polyisocyanate. A method for producing a moisture-curable NCO-terminated urethane prepolymer A, which provides a cured product with water-stopping properties, characterized by reacting the following: 2 a is an aliphatic polyisocyanate and a polyether polyol with an NCO/OH ratio of 1/1.2 to
The manufacturing method according to claim 1, wherein the prepolymer is reacted at a ratio of 1/8. 3 NCO/a aromatic polyisocyanate and a
The manufacturing method according to claim 1 or 2, wherein the reaction is carried out at an OH ratio of 1.4/1 to 3/1. 4. Claims 1 to 4, wherein the polyether polyol has an oxyethylene content of 50 to 100% based on the weight of total oxyalkylene.
The manufacturing method according to any of paragraph 3. 5 Polyether polyol is oxyethylene/
5. The method for producing an oxypropylene copolymer-based polyether polyol according to any one of claims 1 to 4. 6 The hydroxyl equivalent of polyether polyol is 800
~4000, the manufacturing method according to any one of claims 1 to 5. 7. The manufacturing method according to any one of claims 1 to 6, wherein the NCO% of A is 0.05 to 7%.