JP2003336036A - Moisture-curing sealing material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sealing material using a moisture-curing urethane composition which has no foaming caused by carbon dioxide during curing, and excellent heat resistance, water resistance and curability. <P>SOLUTION: The moisture-curing urethane sealing material comprises (A) a urethane prepolymer with two or more isocyanate groups on the terminals thereof which is produced by reacting a polyisocyanate with a polyoxyalkylene polyol having 5 wt.% or more of butylene-ether bond, (B) a urethane compound containing an oxazolidine group, and (C) an aromatic polybasic acid. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a moisture-curable sealing material which is free from foaming due to carbon dioxide during curing and which is excellent in heat resistance, water resistance and curability.

[0002]

2. Description of the Related Art As a conventional moisture-curable urethane composition, Japanese Patent Application Laid-Open No. 57-94056 is known.
There is a problem that the swelling of the coating film often occurs due to carbon dioxide gas generated when moisture reacts with isocyanate groups during curing. Moisture dissociative crosslinking agents such as ketimine and enamine have been proposed in order to suppress the generation of carbon dioxide gas that causes swelling, and among them, JP-A-6-293821,
The composition using an oxazolidine compound proposed in JP-A-7-33852, JP-A-7-10949, etc. is a material having a relatively balanced performance without generation of carbon dioxide gas.

Further, Japanese Patent Application Laid-Open No. 9-169829 proposes a sealing material comprising a urethane prepolymer, an oxazolidine compound, a specific oxazolidine ring-opening promoting compound and the like. However, this composition has no foaming and is excellent in curability. However, when it is used as a sealing material, the physical properties change greatly due to swelling after water resistance, which is not practical.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a sealing material using a moisture-curable urethane composition which is free from foaming due to carbon dioxide during curing and is excellent in heat resistance, water resistance and curability. Is.

[0005]

Means for Solving the Problems As a result of earnest research on these problems, the present inventors have found that A) having two or more isocyanate groups at the terminal obtained by reacting a polyisocyanate with a polyoxyalkylene polyol, and Provided is a urethane prepolymer containing 5% by weight or more of butylene ether bond in a polyoxyalkylene polyol, and (B) an oxazolidine group-containing urethane prepolymer (C) a moisture-curable sealant. It is a thing.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The polyisocyanate used in the present invention has two or more isocyanate groups at the terminal obtained by reacting with a polyoxyalkylene polyol, and the polyoxyalkylene polyol contains 5 wt. % Or more urethane prepolymer (hereinafter referred to as BO component-containing urethane prepolymer) (A)
Is a urethane prepolymer prepared by a conventional method in the presence of an excess of polyisocyanate and a polyoxyalkylene polyol containing 5% by weight or more of butylene ether bond in the amount of polyisocyanate. Further, a urethane prepolymer having two or more isocyanate groups at the end (b
1) is a urethane prepolymer prepared by a conventional method in which a polyisocyanate and a polyol, for example, a polyoxyalkylene polyol such as polyoxyethylene glycol, polyoxypropylene glycol, and polyoxybutylene glycol are prepared in an excess amount of polyisocyanate. is there.

Such polyoxyalkylene polyols are obtained by adding ethylene oxide, propylene oxide, butylene oxide to ethylene glycol, propylene glycol, water, glycerin, TMP, pentaerythritol, etc., alone or in combination of two or more of them by a known method. Is a polyol that can be used.

The polyisocyanates used in the present invention include 2,4-tolylene diisocyanate and 2,6-
Tolylene diisocyanate, diphenyl methane diisocyanate, partially carbodiimidated diphenyl methane diisocyanate, polymethylene polyphenyl polyisocyanate, tolylene diisocyanate, naphthalene diisocyanate, phenylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate , Aromatic diisocyanates such as hydrogenated diphenylmethane diisocyanate and cyclohexane diisocyanate, aliphatic diisocyanates, alicyclic diisocyanates, and one or a mixture of two or more thereof.

Urethane prepolymer containing BO component (A)
The polyoxyalkylene polyol, which is a component of
A diol or triol having a number average molecular weight of 500 to 16000 is preferable. Further, the prepolymer (A)
Is a polyoxyalkylene polyol containing a butylene ether bond in an amount of 5% by weight or more, preferably 5 to 80% by weight, and more preferably 10 to 80% by weight. When the content of such butylene ether bond is low, the water absorption is low and the physical properties after the water resistance test are satisfactory.

Particularly, the polyoxyalkylene polyol component of the urethane prepolymer (A) is preferably in the range of 5 to 80% by weight of butylene ether bond, 0 to 10% by weight of ethylene ether bond and 10 to 95% by weight of propylene ether bond.

Urethane prepolymer containing BO component (A)
The number of terminal isocyanate groups of is preferably 2 or more, more preferably 2-3. Further, the NCO / OH ratio of the isocyanate and the polyol is preferably 1.4 or more, more preferably 1.4 to 5.0. The residual NCO% is preferably 1 to 20% by weight.

On the other hand, the oxazolidine-containing urethane compound (B) has at least one oxazolidine group at the terminal. Preferably, the above-mentioned polyisocyanate or a urethane prepolymer (b1) having two or more isocyanate groups at the terminal obtained by reacting the polyisocyanate with a polyoxyalkylene polyol is reacted with N-2-hydroxyalkyloxazolidine (b2). The resulting terminal has at least one oxazolidine group.

The polyoxyalkylene polyol of the urethane prepolymer preferably has an oxyethylene chain. However, even a polyol obtained by mixing a polyol having no oxyethylene chain and a polyol having an oxyethylene chain can be used as the component (b1). The average content of oxyethylene chains in the oxyalkylene chain is preferably 1 to 30% by weight. When the content of the oxyethylene chain is within the above range, the curing rate is high and the curability, heat resistance and water resistance are excellent. However, the amount of oxyethylene chains of the components (A) and (B) is calculated and summed, and the content of the oxyethylene chains is 1 with respect to the total amount of the components (A) and (B).
It is preferably less than 0% by weight. Within this range, preferable heat resistance and water resistance are obtained.

The urethane prepolymer (b1) preferably has a number average molecular weight of 500 to 8000. When the molecular weight is from 500 to 8000, the followability to the underlayer and the curing rate are satisfied. Also, urethane prepolymer (b1)
The average number of NCO groups at the terminal of is preferably 2.0 to 2.6.
With such an NCO group number, good results can be obtained for curability and substrate followability. Further, the NCO / OH ratio of the isocyanate and the polyol is preferably 1.6 or more, more preferably 1.8 to 4.0. The residual NCO% is preferably 1 to 15% by weight.

The urethane prepolymer (b1) and N-
The reaction molar ratio with the 2-hydroxyalkyloxazolidine (b2) is preferably NCO / 0H = 0.95 to 3.0 / 1. When NCO / 0H is in the range, unreacted N-2-hydroxyalkyloxazolidine has a low tendency to remain, gives good results in storage stability, and easily suppresses a decrease in curing speed and an increase in viscosity. Is.

The N-2-hydroxyalkyloxazolidine (b2) used in the synthesis of the oxazolidine-containing urethane compound (B) is, for example, formaldehyde,
It is a compound obtained by a known condensation reaction of aldehydes such as acetaldehyde, propylaldehyde, butyraldehyde, benzaldehyde and dihydroxyalkylamines such as diethanolamine and dipropanolamine.

Urethane compound containing oxazolidine (B)
The number of terminal oxazolidine groups is preferably 1 to 3. Within this range, the stretchability after curing becomes high, which is preferable. Incidentally, urethane oxazolidine prepolymer (B)
It goes without saying that, as long as there is at least one oxazolidine group at the terminal, the other terminal may be an isocyanate group.

The proportion of the BO component-containing prepolymer (A) and the oxazolidine-containing urethane compound (B) is such that active hydrogen generated by ring opening of the NCO group of the prepolymer (A) and the oxazolidine-containing urethane compound (B) with water. The ratio with the group is preferably in the range of 0.4 to 4.0. Within this range, the generation of carbon dioxide gas is low, the swelling of the coating film can be suppressed, and the storage stability is excellent. Considering these points, the mixing ratio of (A) and (B) is 60: 1 to 1:30 by weight.
Is preferred.

The aromatic polybasic acid (C) includes general compounds such as terephthalic acid, trimellitic acid, pyromellitic acid, mellitic acid, isophthalic acid and orthophthalic acid.
Aromatic polybasic acids selected from terephthalic acid, trimellitic acid, pyromellitic acid, mellitic acid and their anhydrides are preferable, and terephthalic acid is particularly preferable in terms of heat resistance and water resistance. The content of the aromatic polybasic acid (C) is preferably 0.1 to 3.0% by weight in the sealing material. With such a content, heat resistance and water resistance are further improved, which is preferable.

When used in these applications, the sealing material of the present invention contains a solvent, an inorganic filler, a small amount of process oil, a plasticizer, other pigments, and UV protection for improving weather resistance when necessary. It may contain various additives such as agents and stabilizers.

Usual solvents for urethane such as toluene, xylene, terpene and ethyl acetate can be used as the solvent. The amount used is preferably 10% by weight or less in the sealing material.

Examples of the plasticizer include dibutyl phthalate, dioctyl phthalate, diundecyl phthalate,
Ester plasticizers such as dilauryl phthalate, butylbenzyl phthalate, diisodecyl phthalate, dibutyl adipate, dioctyl adipate, diisononyl adipate, diisononyl adipate, dioctyl azelate, dioctyl sebacate, and phosphate ester plasticizers such as trioctyl phosphate and triphenyl phosphate. Agents. The amount used is preferably 15% by weight or less in the sealing material.

Further, examples of the stabilizer include an antioxidant and an ultraviolet absorber.

The sealing material of the present invention is, for example, for construction,
It is useful for civil engineering and the like, and applicable base materials include concrete, asphalt, sizing board, wood, glass, metal and the like.

[0025]

EXAMPLES Next, the present invention will be described in detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples. In the following, all parts and% are based on weight unless otherwise specified.

<Synthesis of Component (A)> (Preparation Example 1 of Urethane Prepolymer) Number Average Molecular Weight 20
00 polybutylene ether diol 500 g (0.2
5 moles), polypropylene ether diol having a number average molecular weight of 2000 400 g (0.2 moles) number average molecular weight 30
00 g polypropylene ether triol 100 g
(0.03 mol), 191.4 g (1.1 mol) of 2,4-tolylene diisocyanate, that is, an NCO / OH equivalent ratio of 2.2, and stirred in a flask at 80 ° C. for 20 hours under a nitrogen stream. While reacting, a urethane prepolymer (A-1) having an NCO% of 4.25% was obtained.

(Preparation Example 2 of Urethane Prepolymer) In Preparation Example 1 of Urethane Prepolymer, the number average molecular weight was 20.
700 g of polybutylene ether diol of 00 (0.3
5 mol) and a number average molecular weight of 2000% and polyethylene propylene ether diol 700 g (0.35 mol) with an ethylene oxide content of 20% were used in the same manner as above, and NCO% was 4.23%. A prepolymer (A-2) was obtained.

<Synthesis of Component B> (Preparation Example 1 of Urethane Oxazolidine Prepolymer) 500 g of polyethylene propylene ether triol having a number average molecular weight of 4,800 and an oxyethylene chain content of 5%
(0.104 mol) and polypropylene ether diol having a number average molecular weight of 2000 (500 g, 0.25 mol) were mixed to obtain an oxyethylene chain having an average content of 7.5%, an average number of functional groups of 2.29, and a number average molecular weight of 2820. A polyol was obtained. Further, hexamethylene diisocyanate 143.
3 g (0.853 mol), that is, an NCO / OH equivalent ratio of 2.1, was allowed to react with stirring in a flask under a nitrogen stream at 80 ° C. for 48 hours, and the NCO% was 3.29%. A urethane prepolymer (b1-1) having a terminal NCO group number of 2.29 was obtained.

Urethane prepolymer (b1-1) 14
0.8 g and 2-isopropyl 3 (2 hydroxyethyl)
1,3 Oxazolidine 15.9 g, ie NCO / O
The urethane oxazolidine prepolymer (OXZ-1) was obtained by reacting with an equivalent ratio of H of 1.1 under a nitrogen stream at 60 ° C. for 48 hours while stirring in a flask. As a result of measuring GPC of this composition, it was confirmed that the content rate of the remaining 2-isopropyl3 (2hydroxyethyl) 1,3oxazolidine was 1% or less.

(Preparation Example 2 of Urethane Oxazolidine Prepolymer) 20 g (0.033 mol) of polyethylene propylene ether triol having a number average molecular weight of 600 and an oxyethylene chain content of 30% and 270 g of polypropylene ether diol having a number average molecular weight of 600 (0 .45 moles) and the average content of oxyethylene chains is 2.1.
%, The average number of functional groups was 2.07, and a polyol having a number average molecular weight of 600 was obtained. Further, 174 g (1.0 mol) of 2,4 tolylene diisocyanate, that is, an NCO / OH equivalent ratio of 2.0, was reacted under nitrogen flow at 60 ° C. for 48 hours while stirring in a flask to have a NCO% of 9. A urethane prepolymer (b1-2) having 07% and a terminal NCO group number of 2.07 per molecule was obtained.

Urethane prepolymer (b1-2) 48.
7 g and 2-isopropyl 3 (2 hydroxyethyl) 1,
3 Oxazolidine (15.9 g), that is, NCO / OH equivalent ratio 1.05, was reacted with stirring in a flask under a nitrogen stream at 60 ° C. for 48 hours to obtain a urethane oxazolidine prepolymer (OXZ-2). G of this composition
As a result of measuring PC, the remaining 2-isopropyl-3
It was confirmed that the content of (2 hydroxyethyl) 1,3 oxazolidine was 1% or less.

<Composition of compound> Next, calcium carbonate which was dried in a closed planetary mixer under reduced pressure at 120 ° C. for 5 hours to adjust the water content to 0.1% or less: 300 parts of Viscolite OS (manufactured by Shiraishi Industry Co., Ltd.), 80 parts of dioctyl phthalate, 0.08 part of salicylic acid, the polymer component shown in the table below, and a predetermined amount of finely powdered terephthalic acid and 110 parts.
Hydrophobic silica whose moisture content is adjusted to 0.05% or less by mixing and drying at 0 ° C. for 2 hours under atmospheric pressure: 45 parts of RY-200 (manufactured by Nippon Aerosil Co., Ltd.) and 80 parts of xylene are added and uniformly mixed, and then 60 Torr Defoaming was carried out under reduced pressure to obtain a moisture-curable urethane compound.

[Test Method] (Curability Test) Curability is determined by pouring a sample at a ratio of 1.5 mm thickness on a glass plate (30 * 30 cm) surrounded by frames on four sides and having a release paper attached, at 25 ° C. × 50. % Under the condition of being touched with a finger and the time until the movement of the coating film disappeared was measured.

(Non-foaming test) For non-foaming property, a sample was cast on a slate plate (30 × 30 cm) surrounded by four sides at a thickness of 2 mm and cured at 50 ° C. × 90%. After that, the presence or absence of blisters and pinholes on the surface of the coating film was observed.
Those with no blisters and pinholes were marked with O, and those with blisters and pinholes were marked with x.

(Viscosity stability test) The viscosity of a sample previously adjusted to 25 ° C. was measured with a BS type rotational viscometer to obtain an initial viscosity (mPa).
/ 25 ° C). Separately fill the sample of the same lot into a 500CC container, seal it, leave it in a dryer at 50 ° C for 7 days, and then
It was left for 15 hours or more in an atmosphere of ° C. After that, the sample was taken out, and the viscosity was measured by the same method as the method for measuring the initial viscosity. The viscosity change rate (%) was calculated by (viscosity after storage) ÷ (viscosity before storage) × 100.

(Slump test) JIS-A-5758
The slump (length) was tested according to the 7.2.1 Slump test method (1997 edition) to measure the slump length (mm).

(Tensile physical property test) JIS-A-5758
A test piece was prepared in accordance with the 7.1 Tensile property test method of (1997 edition), aged at 25 ° C. for 28 days, and then subjected to a tensile test at a tensile speed of 50 mm / min to obtain a modulus at 50% elongation ( kg / cm ² ), tensile strength (kg / cm ² ), and breaking elongation (%) were determined.

(Water resistance test) A test piece prepared according to the normal tensile properties test method was immersed at 60 ° C. for 7 days and then at 25 ° C. ×
50% modulus, tensile strength (kg / cm ² ), elongation at break according to normal tensile properties test method after standing for 4 hours under 50% condition
(%) Was measured.

(Heat Resistance Test) A test piece prepared according to the normal tensile properties test method was cured at 80 ° C. for 7 days and then at 25 ° C.
50% modulus, tensile strength (kg / cm ² ), elongation at break according to normal tensile properties test method after standing for 4 hours under 50% condition
(%) Was measured.

[0040]

[Table 1] [Compounding conditions and test results]

The composition containing no butylene ether bond in Comparative Example 1 was not suitable for practical use because of a large decrease in physical properties after water resistance. Further, the composition containing no butylene ether bond and aromatic polycarboxylic acid of Comparative Example 2 was not suitable for practical use because the physical properties after heat resistance and after water resistance were large.

[0042]

EFFECTS OF THE INVENTION The present invention provides a moisture-curable sealing material which is free from foaming due to carbon dioxide during curing and is excellent in heat resistance, water resistance and curability.

Continued front page    F-term (reference) 4H017 AA04 AA31 AB03 AC05 AD06                       AE03                 4J034 BA03 CE04 DA01 DB04 DC50                       HC03 HC12 HC17 HC45 HC46                       HC52 HC53 HC61 HC71 HD15                       JA42 KD02 RA08

Claims (2)

[Claims] 1. A urethane having (A) two or more isocyanate groups at the terminal obtained by reacting a polyisocyanate with a polyoxyalkylene polyol, and containing 5 wt% or more of butylene ether bond in the polyoxyalkylene polyol. A moisture-curable urethane sealing material containing a prepolymer, (B) an oxazolidine group-containing urethane compound, and (C) an aromatic polybasic acid. 2. The polyoxyalkylene polyol component of the urethane prepolymer (A) is a butylene ether bond 5.
The moisture-curable urethane sealing material according to claim 1, wherein the moisture-curable urethane sealing material has an amount of -80% by weight, an ethylene ether bond of 0-10% by weight and a propylene ether bond of 10-95% by weight.