JPH06172706A - Moisture-curing polyurethane composition - Google Patents

Abstract

PURPOSE:To obtain a moisture-curing polyurethane compsn. excellent in curing speed, little in foaming properties and excellent in storage stability. CONSTITUTION:This moisture-curing polyurethane compsn. comprises a urethane prepolymer having at least 2 isocyanate groups in the molecular terminals thereof and a tert. amine (catalyst), e.g. an aliph. diamine, and if necessary a monoisocyanate added thereto, and has an unreacted polyisocyanate content of at most 3wt.%.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a sealant, a road, a floor, a roof, a resin which is cured by reacting with moisture in the air.
Waterproof material for athletic stadium track, athletic field, horse race track,
The present invention relates to a moisture-curable polyurethane composition suitable for paving materials.

[0002]

2. Description of the Related Art Conventionally, sealing materials, waterproof materials, floor materials,
In pavement materials, polyurethane is often used because of its water resistance, chemical resistance, and mechanical properties. Usually, this polyurethane is often used as a so-called two-component polyurethane composition that is reactively cured by mixing a main agent and a curing agent, but it has a troublesome handling associated with the two-component mixing. Therefore, Japanese Patent Application Laid-Open No. 57-94056 discloses a so-called moisture-curable one-component type polyurethane composition in which a urethane prepolymer is cured by moisture in the atmosphere.

[0003]

However, the above-mentioned Japanese Unexamined Patent Application Publication No.
The composition described in JP-A 7-94056 requires at least half a day of curing until the coating film is cured even if it is applied at room temperature, and is much larger under conditions where the amount of water in the atmosphere such as winter is particularly small. Was something that needed time.

Generally, addition of a catalyst can shorten the curing time, but addition of a catalyst causes foaming of a coating film, deterioration of mechanical properties, deterioration of weather resistance, and further storage of a composition. Due to problems such as reduced stability, the addition of catalyst had to be minimized. The problem to be solved by the present invention is that there is little problem such as foaming of coating film, deterioration of mechanical properties, deterioration of weather resistance, further deterioration of storage stability of the composition, and moisture curing having a remarkably excellent curing rate. A type polyurethane composition is provided.

[0005]

As a result of earnest studies, the present inventors have found that the above problems can be solved by using a urethane prepolymer in combination with a tertiary amine catalyst, and have completed the present invention. .

That is, the present invention relates to a moisture-curable polyurethane composition obtained by adding a tertiary amine catalyst to a urethane prepolymer having at least two isocyanate groups at its terminals.

The urethane prepolymer used in the present invention is usually a polyisocyanate and a polyol (hereinafter,
It is obtained by reacting with (also simply referred to as polyol), and has at least two or more isocyanate groups at the terminal.

Polyisocyanate is, for example, 2,4-
Tolylene diisocyanate (hereinafter abbreviated as TDI), 6
5 / 35-TDI, 80 / 20-TDI, 4,4 ′ diphenylmethane diisocyanate (hereinafter abbreviated as MDI), dianisidine diisocyanate, tridene diisocyanate, metaxylylene diisocyanate, Organic selected from aromatic diisocyanates and alicyclic diisocyanates such as hexamethylene diisocyanate, phenylene diisocyanate, 1,5 naphthalene diisocyanate, polymethylene polyphenyl polyisocyanate, hydrogenated MDI and hydrogenated TDI Organic polyisocyanates such as diisocyanate compounds may be mentioned. Among them, TDI, 65 /
35-TDI, 80 / 20-TDI, hydrogenated TDI, M
DI and hydrogenated MDI are preferred. These organic isocyanates can be used alone or as a mixture thereof.

As the polyol, there are 2 hydroxyl groups in the molecule.
Have one or more, for example, polyester polyols, polyether polyols, polyester polyamide polyols, polycarbonate polyols,
Polycaprolactone polyester polyols, polybutadiene polyols, polypentadiene polyols, castor oil-based polyols, low molecular weight diols, trimethylolpropane, glycerin, sorbitol, mannitol, dulcitol, etc. From the viewpoint of excellent hydrolyzability, polyether polyols and polybutadiene polyols are preferable.

Specific examples of the above polyether polyol and polybutadiene polybutadiene polyol include polypropylene ether glycol, polyethylene propylene ether glycol, polytetramethylene ether glycol, polybutadiene glycol and the like.

When the above-mentioned polyol is used as a urethane prepolymer, it has a low viscosity and can have a low foaming property, so that it preferably has a molecular weight of 500 to 30,000. In particular, the balance between the low viscosity and the low foaming property is remarkable. A polymer having a molecular weight of 1,000 to 20,000 is more preferable because it is excellent. The above-mentioned polyethers may be used alone in the reaction with polyisocyanates or may be used in mixtures thereof.

The above-mentioned reaction ratio between the polyol and the polyisocyanate is such that the equivalent ratio of NCO / OH is 1.3 to 2.5, so that the viscosity of the produced prepolymer can be lowered and the composition is cured. It is preferable from the standpoint of excellent carbon dioxide absorption effect, and it is more preferable that the equivalent ratio of NCO / OH is 1.5 to 2.3 because this effect becomes more remarkable.

The urethane prepolymer used in the present invention preferably has a molecular weight of 800 to 46000 because it has a low viscosity and a low foaming property.
This effect becomes remarkable in the case of 300 to 31000. In addition, the content of unreacted polyisocyanate in the prepolymer after synthesizing the prepolymer is preferably 3% by weight or less, and particularly preferably 2% by weight or less in order to prevent foaming of the coating film.

The above-mentioned urethane prepolymer has at least two isocyanate groups in its skeleton, but from the viewpoint of excellent storage stability, it is preferable to have 2 to 5 isocyanate groups, especially 2 to 3 isocyanate groups. Those are preferable.

When the urethane prepolymer of the present invention is produced, any combination of polyisocyanate and polyol can be used and is not particularly limited. For example, a reaction product of polypropylene ether glycol and TDI is produced. , A reaction product of polypropylene ether glycol and 65 / 35-TDI, a reaction product of polypropylene ether glycol and 80 / 20-TDI, a reaction product of polypropylene ether glycol and hydrogenated TDI, polypropylene ether glycol and MDI Polypropylene ether glycol-based urethane prepolymers such as reaction products of polypropylene ether glycol and hydrogenated MDI, reaction products of polyethylene propylene ether glycol and TDI, poly Reaction product of ethylene propylene ether glycol and 65 / 35-TDI, reaction product of polyethylene propylene ether glycol and 80 / 20-TDI, reaction product of polyethylene propylene ether glycol and hydrogenated TDI, polyethylene propylene ether glycol Polyethylene propylene ether glycol-based urethane prepolymers such as reaction products of propylene and MDI, reaction products of polyethylene propylene ether glycol and hydrogenated MDI, reaction products of polytetramethylene ether glycol and TDI, polytetramethylene ether Reaction product of glycol and 65 / 35-TDI, reaction product of polytetramethylene ether glycol and 80 / 20-TDI, polytetramethylene ether glycol and hydrogenated TD The reaction product of,
Polytetramethylene ether glycol-based urethane prepolymers such as reaction products of polytetramethylene ether glycol and MDI, reaction products of polytetramethylene ether glycol and hydrogenated MDI, reaction products of polybutadiene glycol and TDI, A reaction product of polybutadiene glycol and 65 / 35-TDI, a reaction product of polybutadiene glycol and 80 / 20-TDI, a reaction product of polybutadiene glycol and hydrogenated TDI, a reaction product of polybutadiene glycol and MDI, Examples thereof include polybutadiene glycol-based urethane prepolymers such as reaction products of polybutadiene glycol and hydrogenated MDI. Among them, polypropylene ether glycol-based urethane prepolymers or polyethylene propylene Ether glycol urethane prepolymer is preferable from the viewpoint becomes more remarkable effect of the present invention.

The tertiary amine catalyst used in the present invention has at least one tertiary amine group in the molecule, and specifically includes triethylamine, dimethylcyclohexylamine, tetramethylethylenediamine, tetramethylpropanediamine, tetra Methylhexanediamine, pentamethyldiethylenetriamine, pentamethylpropylenetriamine, tetramethylguanidine, triethylenediamine, dimethylpiperazine, methyldimethylaminoethylpiperazine, methylmorpholine, dimethylaminoethylmorpholine, dimethylimidazole, dimethylaminoethanol, dimethylaminotriethoxyethanol, Trimethylaminoethylethanolamine, methyl-2-hydroxyethylpiperazine, 2-hydroxyethylpiperazine Bis 2-dimethylaminoethyl ether, ethylene glycol bis 3-methylamino-propyl ether known catalysts are used.

Among them, tetramethylethylenediamine, tetramethylpropanediamine, represented by the following formula,
Tertiary amine-based catalysts such as tetramethylhexanediamine are preferable because they have less problems such as foaming of the coating film, deterioration of mechanical properties, deterioration of weather resistance, and further deterioration of storage stability of the composition. (R ₁ , R ₂ , R ₃ and R ₄ are alkyl groups having 1 to 3 carbon atoms, R 1
₅ is an alkylene group having 1 to 10 carbon atoms)

The amount of the tertiary amine catalyst compounded is preferably 0.001 to 3% by weight, based on the total weight of the composition.
3 to 2% by weight is more desirable. When the amount of the tertiary amine-based catalyst is in the above range, the curing rate of the composition is sufficiently shortened, the foaming of the coating film is suppressed to be low, and the weather resistance and the storage stability of the composition are excellent, which is preferable. . Further, the tertiary amine-based catalyst is used in combination with other curing catalysts to the extent that problems such as foaming of coating film, deterioration of mechanical properties, deterioration of weather resistance, and deterioration of storage stability of the composition are not serious. Good. Also,
The tertiary amine catalyst may be blended in the urethane prepolymer in advance, or may be mixed with the urethane prepolymer before use.

By using a monoisocyanate together in the present invention, a composition having further excellent storage stability can be provided. The monoisocyanate is not particularly limited, but is preferably one having a molecular weight of 500 or less from the viewpoint of excellent reaction with water and further improved storage stability. Among them, those having a molecular weight of 300 to 100 are preferable because they are particularly excellent in storage stability.

Specific examples of the monoisocyanate include paratoluenesulfonyl isocyanate (molecular weight 197) and tridecyl isocyanate (molecular weight 23).
5), octadecyl isocyanate (molecular weight 295),
Phenyl isocyanate and the like are used, but among them, paratoluene sulfonyl isocyanate (molecular weight 197)
Is preferred.

The content of the monoisocyanate is preferably 0.01 to 7% by weight in the composition from the viewpoint of storage stability of the composition, and more preferably 0.05 to 5.5% by weight. Are more preferable because these effects are remarkable.

In the composition of the present invention, if necessary, a solvent, a small amount of process oil, a plasticizer, a thixotropic agent, an extender pigment, an antifoaming agent, an ultraviolet ray inhibitor for maintaining and improving weather resistance, and a stability. Various additives such as agents are added, and the mixture can be uniformly mixed and can be produced by a mixing and kneading device sufficient to ensure storage stability.

Usual solvents for urethane such as toluene, xylene, terpene and ethyl acetate can be used as the solvent. As the process oil, an ordinary high boiling point oil obtained by refining oil can be used.

As the plasticizer, general plasticizers such as dioctyl phthalate, dibutyl phthalate and dinonyl phthalate can be used.

Examples of extender pigments include carbon black, calcium carbonate, talc, clay, silica and titanium oxide.

Examples of the thixotropic agent include polyvinyl chloride powder, finely divided silica and bentonite.

Examples of the antifoaming agent include calcium hydroxide and magnesium hydroxide. In addition to this, the urethane resin composition of the present invention may be mixed with a petroleum-based high-boiling point aromatic fraction, a petroleum resin, or the like.

The moisture-curable polyurethane composition of the present invention can suppress the foaming of the coating film to a low level by containing a tertiary amine-based catalyst, resulting in a marked deterioration in mechanical properties and weather resistance after moisture curing. Further, the composition before curing has excellent storage stability, and particularly when a monoisocyanate is used in combination, the composition exhibits further excellent storage stability.

The moisture-curable polyurethane composition of the present invention is a sealing material by reacting with moisture in the air,
It can be applied to waterproofing materials and pavement materials for roads, floors, roofs, athletic stadium track, athletic field, horse racing track.

[0030]

EXAMPLES Examples will be shown below, but the present invention is not limited to these examples. In the following examples,% is based on weight.

(Preparation Example 1 of Prepolymer) Average molecular weight 2
000, polypropylene ether glycol having an average number of functional groups of 2 300 g (0.15 mol), average molecular weight 600
0, 1,400 g (0.23 mol) of polyethylene propylene ether glycol having an average number of functional groups of 3, 4,250 g (1.0 mol) of 4,4′-diphenylmethane diisocyanate, that is, an equivalent ratio of NCO / OH of 2.0 under a nitrogen stream. A urethane prepolymer (P-1) was obtained by reacting at 80 ° C. for 8 hours with stirring in a flask. The obtained prepolymer contained 2.16% of unreacted 4,4′-diphenylmethane diisocyanate.

(Preparation Example 2 of Prepolymer) Average molecular weight 5
000, and 1667 g (0.33 mol) of polypropylene ether glycol having an average number of functional groups of 3, 262.5 g (1.05 mol) of 4,4′-diphenylmethane diisocyanate, that is, an NCO / OH equivalent ratio of 2.1 under a nitrogen stream. Then, the mixture was reacted at 80 ° C. for 8 hours with stirring in a flask to obtain a urethane prepolymer (P-2). The obtained prepolymer contained 2.40% of unreacted 4,4′-diphenylmethane diisocyanate.

Test Method (Curability Test) The curability is determined by pouring the sample on a slate plate (30 × 30 cm) surrounded by a frame on all sides at a rate of 2 mm, taking care not to entrap bubbles at 20 ° C. 50%
And, after putting it in a constant temperature and constant humidity tank adjusted to 10 ° C x 50%, the sample surface is touched with a finger every 15 minutes, and JISA-540 is used.
The time required for curing and drying defined by 0 is measured.

(Cured physical property test) Regarding the cured physical properties, the sample is poured on a glass plate whose four sides are surrounded by a frame and whose surface is covered with a release paper, taking care not to entrap bubbles at a rate of 2 mm,
After leaving it for 14 days at room temperature to cure it, JISA-60
Normal tensile strength, tear strength, and breaking elongation are measured by the method specified in No. 21.

(Foamability test) With respect to foamability, the sample was poured on a slate plate (30 × 30 cm) surrounded by four sides with a thickness of 2 mm, taking care not to entrap bubbles at 40%.
After curing under the condition of ° C x 60%, the presence or absence of blisters and pinholes on the coating film surface was observed. Those without blisters and pinholes were marked with O, those with few blisters and pinholes were marked with Δ, and those with many blisters and pinholes were marked with x.

(Storage stability test) Storage stability is 500C
A metal can of C was filled with 400 g of the sample, and after tightly capping, 40
Curing was carried out for 7 days under the condition of ° C, and the increase rate of the viscosity after curing was measured as compared with the viscosity before curing. The viscosity of the sample should be 2
The temperature was adjusted to 5 ° C., the sample was stirred with a spatula for 1 minute, and then measured with a BH type rotational viscosity type.

(Example 1) 400 g of prepolymer (P-1) was dried in a closed planetary mixer at 150 ° C. for 2 hours, and calcium carbonate whose water content was adjusted to 0.05% or less (manufactured by Nitto Koka kk) NS-1000) 350 g, xylene 150 g, and dibutyl phthalate 30 g were added and uniformly mixed, followed by drying at 150 ° C. for 2 hours to obtain a water content of 0.05.
%, Fine powdery calcium hydroxide (tosa lime kk slaked lime salt baked) 100 g, tetramethylhexanediamine 15 g, and paratoluenesulfonyl isocyanate 15 g were added and uniformly mixed to obtain a moisture-curable urethane compound.

Using this compound, a curability test, a cured physical property test, a foamability test, and a storage stability test were conducted. The results are shown in Table 1.

Example 2 In place of the prepolymer (P-1) used in Example 1, prepolymer (P-2) 400 was used.
The same treatment as in Example 2 was performed using g to obtain a moisture-curable urethane compound. Using this compound, a curability test, a cured physical property test, a foamability test, and a storage stability test were conducted. The results are shown in Table 1.

(Example 3) The same treatment as in Example 2 was carried out without adding tetramethylhexanediamine in Example 1 to obtain a moisture-curable urethane compound. Immediately before the test, 15 g of tetramethylhexanediamine was added to 1000 g of this compound, and the mixture was stirred with a Desper for 30 seconds, depressurized by a vacuum pump to defoam, and a curability test, a cured physical property test and a foamability test were conducted. The results are shown in Table 1.

Example 4 In Example 1, 1.0 g of triethylenediamine was used instead of tetramethylhexanediamine, the amount of fine powdery calcium hydroxide added was changed to 20 g, and paratoluenesulfonyl isocyanate was added. Then, the same treatment as in Example 1 was carried out to obtain a moisture-curable urethane compound. Using this compound, a curability test, a cured physical property test, a foamability test, and a storage stability test were conducted. The results are shown in Table 1.

Comparative Example 1 A moisture-curable urethane compound was obtained by carrying out the same treatment as in Example 1 without adding tetramethylhexanediamine and paratoluenesulfonyl isocyanate. Using this compound, a curability test, a cured physical property test, a foamability test, and a storage stability test were conducted. The results are shown in Table 1.

Comparative Example 2 A moisture-curable urethane was prepared in the same manner as in Example 1 except that p-toluenesulfonyl isocyanate was not added in Example 1 but 1.0 g of dibutyltin dilaurate was added instead of tetramethylhexanediamine. I got a compound. Using this compound, a curability test, a cured physical property test, a foamability test, and a storage stability test were conducted. The results are shown in Table 1.

[0044]

[Table 1]

[0045]

EFFECT OF THE INVENTION The moisture-curable polyurethane composition of the present invention can suppress the foaming of the coating film to a low level by containing a tertiary amine-based catalyst, and can significantly reduce mechanical properties and weather resistance after moisture curing. In addition, the composition is excellent in storage stability before being cured, and particularly when a monoisocyanate is used in combination, further excellent storage stability is exhibited.

Claims (6)

[Claims] 1. At least 2 isocyanate groups at the end.
A moisture-curable polyurethane composition, characterized in that a tertiary amine catalyst is added to each urethane prepolymer. 2. The composition according to claim 1, wherein the tertiary amine catalyst has a structure represented by the following formula. (R ₁ , R ₂ , R ₃ and R ₄ are alkyl groups having 1 to 3 carbon atoms, R 1
₅ is an alkylene group having 1 to 10 carbon atoms) 3. The composition according to claim 1, wherein the urethane prepolymer is obtained by reacting a polyisocyanate and a polyol, and contains 3% by weight or less of unreacted polyisocyanate. Stuff. 4. The composition according to claim 1, which contains monoisocyanate as an essential component. 5. A monoisocyanate in the composition of 0.01 to
The composition according to claim 4, which is contained at 7% by weight. 6. The composition according to claim 4, wherein the monoisocyanate has a molecular weight of 500 or less. [0000]