JPH07216044A - Method for curing isocyanate composition containing aldimine - Google Patents

Abstract

PURPOSE:To simply cure an isocyanate composition containing aldimine at a low temperature and a low humidity into a cured material useful for a coating compound, a floor covering material, etc., free from foaming by mixing a specific isocyanate composition with an organic acid. CONSTITUTION:(A) An isocyanate composition comprising an isocyanate group- containing polyurethane prepolymer and a polyaldimine of the formula (X is a 6-15C aryl; Y is a bifunctional or (a) trifunctional 2-15C hydrocarbon group or a bifunctional or a trifunctional polyoxyalkylene having 70-6,000 molecular weight; (n) is 2 or 3) is mixed with (B) an organic acid such as acetic acid, methanesulfonic acid or methyl acid phosphate to cure the component A.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for curing an isocyanate composition containing a latent curing agent which hydrolyzes to form a polyamine, and more particularly to a method for curing an isocyanate composition by mixing an organic acid.

[0002]

2. Description of the Related Art Polyurethane resin is excellent in various properties such as rubber elasticity, abrasion resistance, and durability, and therefore, as a paint, floor material, waterproof material, adhesive, potting material, wall material, sealing material, etc. It has been especially used in recent years. The curing method of these polyurethane resins is a one-component type in which the terminal NCO group of the polyurethane prepolymer is cured by water in the atmosphere after the construction, and a curing agent containing a main agent containing the polyurethane prepolymer and polyols is applied. It is roughly classified into a two-component type which is mixed and cured at times.

In the two-pack type, the curing rate can be easily adjusted, but it is necessary to measure each component and stir and mix at the time of construction. Therefore, the physical properties of the cured product may be deteriorated or the curing may be defective due to an error in the weighing and stirring / mixing operation. On the other hand, the one-pack type is easy to apply, but has drawbacks such as slow curing and foaming. As a method of remedying these drawbacks, latent hardeners such as enamine (UK patent 1575666),
Polyaldimines or polyketimines (UK patent 1064
841, German Patent 3133769, JP-A-2-2837.
10, JP-A-4-279620), a composition containing β-lactam (JP-A-2-168), and the like have been proposed.
In particular, the composition containing polyaldimine as disclosed in JP-A-4-279620 is excellent not only in curability but also in storage stability, so that it can be used in many products. However, these compositions have drawbacks such as a marked decrease in curability when applied in a low temperature and low humidity environment such as in winter. There is also a method of adding an organic acid to the composition in advance for the purpose of improving the curability, but in this case, the long-term storability of the composition deteriorates in proportion to the amount added, which is not practical.

[0004]

In order to overcome the above problems, excellent curability can be obtained even in a low temperature and low humidity environment, and the cured product does not have foaming and always has uniform physical properties. A method for curing the resulting isocyanate composition has been strongly desired.

[0005]

The inventors of the present invention have arrived at the present invention as a result of intensive research on the above problems. That is, the present invention, a polyurethane prepolymer having an isocyanate group, and an isocyanate composition containing a latent curing agent that produces an amine by hydrolysis, by adding and mixing an appropriate amount of an organic acid immediately before construction, A method for curing an isocyanate composition, which is characterized by having excellent curability even in winter and obtaining uniform physical properties of a cured product.

That is, the present invention relates to a polyurethane prepolymer having an isocyanate group and the following general formula (I)

Embedded image Y-(— N═CH—X) n (I) (In the formula, X is an aryl group having 6 to 15 carbon atoms, and Y is a divalent or trivalent hydrocarbon group having 2 to 15 carbon atoms. Group or a divalent or trivalent polyoxyalkylene group having a molecular weight of 70 to 6000, and n is 2 or 3) is mixed with an isocyanate composition containing an organic acid and cured. Is the way.

Next, the present invention will be described in detail. In the present invention, the isocyanate composition contains a polyurethane prepolymer having an isocyanate group and a polyaldimine which produces an amine by hydrolysis.
The following general formula (I) (Chemical formula 3)

Embedded image Y-(— N═CH—X) n (I) (In the formula, X is an aryl group having 6 to 15 carbon atoms, and Y is a divalent or trivalent hydrocarbon group having 2 to 15 carbon atoms. Group or a divalent or trivalent polyoxyalkylene group having a molecular weight of 70 to 6000, n is 2 or 3), and the polyamine used for the production of the polyaldimine is 1) ethylenediamine, 1, Aliphatic diamines such as 3-diaminopropane, tetramethylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, decamethylenediamine, 4,4′-diaminodicyclohexylmethane, isophoronediamine, bisaminomethylcyclohexane, 2, 5-or 2,6-
Diamino methyl bicyclo [2.2.1] heptane, diaminocyclohexane, 3 (4), 8 (9) - bis (aminomethyl) - tricyclo [5.2.1.0 ^2.6] alicyclic diamines decane, Aromatic diamines such as diaminodiphenylmethane, diaminodiphenyl ether, xylylenediamine, phenylenediamine, 3,5-diethyltoluene-2,4- or 2,6-diamine, water, ethylene glycol, propylene glycol, etc., and propylene oxide and / or A diamine such as a polyoxyalkylenediamine obtained by converting a hydroxyl group of a polyoxyalkylene glycol obtained by addition polymerization of ethylene oxide into an amino group, 2) 1,3,5-tris (aminomethyl) benzene,
Conversion of hydroxyl groups of polyoxyalkylene triols obtained by addition polymerization of propylene oxide and / or ethylene oxide to triamines such as 1,3,5-tris (aminomethyl) cyclohexane, glycerin and trimethylolpropane to amino groups Triamine such as polyoxyalkylene triamine obtained by the above process, and the like.

Examples of the aldehyde to be reacted with the polyamine include benzaldehyde, o-tolualdehyde, m-tolualdehyde, p-tolualdehyde,
There are 4-ethylbenzaldehyde, 4-propylbenzaldehyde, 4-butylbenzaldehyde, 2,4-dimethylbenzaldehyde, 2,4,5-trimethylbenzaldehyde, p-anisaldehyde, p-ethoxybenzaldehyde and the like.

The polyaldimine represented by the above general formula (I) is obtained by reacting the above polyamine and the above aldehyde with a solvent such as toluene or xylene under an acid catalyst.
An azeotropic dehydration reaction is carried out and the reaction is continued into the water droplet separator until the distillation of water stops. The ratio of the polyamine to the aldehyde is appropriately 1 to 2 equivalents of aldehyde with respect to 1 equivalent of amine.

The polyurethane prepolymer having an isocyanate group is a known polyisocyanate compound and a known compound having two or more active hydrogens in one molecule such as polyol and polyamine so that the free isocyanate group remains by a known method. It was made to react to. That is, a polyisocyanate compound and a compound having active hydrogen are added in an amount of 10
It is produced by reacting at 0 ° C. for several hours. The isocyanate group content is preferably 0.3 to 20.0% by weight, and a particularly preferred range is 0.5 to 15.0% by weight.

Known polyisocyanate compounds are: 1) Tolylene diisocyanate (including various mixtures of isomers), diphenylmethane diisocyanate (including various mixtures of isomers), 3,3'-dimethyl-4,4'-
Biphenylene diisocyanate, 1,4-phenylene diisocyanate, xylylene diisocyanate, tetramethyl xylylene diisocyanate, naphthylene diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, hydrogenated xylylene diisocyanate, 1,4 -Cyclohexyl diisocyanate, 1
-Methyl-2,4-diisocyanato-cyclohexane,
Diisocyanates such as 2,4,4-trimethyl-1,6-diisocyanato-hexane; 2) triisocyanates such as 4,4 ′, 4 ″ -triphenylmethane triisocyanate and tris (4-phenylisocyanato) thiophosphate; 3) Urethane-modified products of the above isocyanates, isocyanurate-modified products, carbodiimide-modified products, biuret-modified products, crude tolylene diisocyanates, polyfunctional isocyanates such as polymethylene polyphenyl isocyanate, and the like.

Known compounds having two or more active hydrogens in one molecule are compounds having two or more hydroxyl groups, one or more amino groups, two or more mercapto groups, a hydroxyl group and an amino group. Or a compound having a hydroxyl group and a mercapto group, for example, water, ethylene glycol, propylene glycol, glycerin, trimethylolpropane, pentaerythritol, sorbitol, sucrose and other polyhydric alcohols, aniline, tolylenediamine, p, Aromatic amines such as p′-diamino-diphenylmethane, aliphatic amines such as ethylenediamine, ethanolamine, diethanolamine, and alkanolamines, and one or a mixture of two or more of these compounds with propylene oxide or propylene oxide and ethylene. -Polyether polyols obtained by addition polymerization of oxides, polyether polyamines obtained by converting hydroxyl groups of the polyether polyols into amino groups, polytetramethylene ether polyols, polycarbonate polyols, polycaprolactone polyols , Polyester polyols such as polyethylene adipate, polybutadiene polyols, esters of higher fatty acids such as castor oil, polymer polyols obtained by grafting vinyl monomers onto polyether polyols or polyester polyols, 1 per molecule Examples thereof include compounds obtained by copolymerizing known ethylenically unsaturated monomers having one or more active hydrogens, ethers having a mercapto group, and the like.

The isocyanate composition used in the present invention comprises the above polyaldimine and the above polyurethane prepolymer having an isocyanate group, and the number of amino groups of the polyamine produced by hydrolysis of the polyaldimine and the polyurethane prepolymer having an isocyanate group are obtained. It is obtained by mixing in a ratio such that the ratio with the number of isocyanate groups contained is 0.5 to 2.0, preferably 0.7 to 1.5.

The isocyanate composition used in the present invention has a viscosity, a resin physical property, a physical property of
A filler, a thixotropy imparting agent, a plasticizer, a solvent, an adhesion imparting agent, a coloring agent, a stabilizer and the like can be mixed and used in order to adjust the resistance.

The organic acids used in the present invention include acetic acid, propionic acid, octylic acid, stearic acid, carboxylic acids such as monochloroacetic acid, trichloroacetic acid, benzoic acid and acrylic acid, methanesulfonic acid, toluenesulfonic acid and dodecylbenzenesulfone. Sulfonic acid such as acid, acid phosphate such as methyl acid phosphate, isopropyl acid phosphate, butyl acid phosphate, 2-ethylhexyl acid phosphate, diethyl phosphite, diisopropyl phosphite, phosphite such as dibutyl phosphite, etc. Is.

The mixing of the isocyanate composition and the organic acid may be carried out by a generally-used electric mixer such as stirring in a container, manual stirring, static mixer, and collision mixing type spraying device. May be used,
Further, the method is not limited to these methods. In order to efficiently mix with the isocyanate composition, an organic acid may be mixed with a solvent inert to isocyanate such as hydrocarbon, ketone, ether or ester. The mixing amount of the organic acid varies depending on the target curing speed, but the organic acid is added in an amount of 0.
It is from 01 part to 5 parts, preferably from 0.05 part to 2 parts.

[0017]

In the present invention, a polyurethane composition containing a polyaldimine, which produces an amine by hydrolysis, and a polyurethane prepolymer having an isocyanate group, is mixed with an organic acid immediately before construction so that the composition can be used at a low temperature in winter. Has excellent curability even in a low humidity environment,
A cured product with uniform properties can be obtained without foaming.

[0018]

EXAMPLES Examples of the present invention will be described below. In the examples, “part” means “part by weight”. Synthesis Example of Polyaldimine Synthesis Example 1 88 parts of tetramethylenediamine (2.0 parts) was added to a reaction vessel equipped with a stirrer, a thermometer, a dropping funnel, and a water separator.
(Equivalent weight) and 500 parts of toluene were charged and mixed under a nitrogen stream at room temperature. After about 10 minutes, 300 parts (2.5 equivalents) of p-tolualdehyde was added dropwise from the dropping funnel in about 30 minutes. The temperature was further raised, reflux started at about 90 ° C., and separation and distillation of water was observed in the water separator. Then, the reaction was continued while refluxing for about 6 hours until the water distillation stopped. The water distilled off was 36 parts. Next, the external temperature was set to 150 ° C. Subsequently, the pressure was reduced to 1 mmHg with a vacuum pump, and toluene and unreacted p-tolualdehyde were distilled off. The reaction product (A-1) obtained after the distillation was 290 parts. As a result of measuring the infrared absorption spectrum of the obtained reaction product,
A characteristic absorption spectrum of -N = CH- was observed at 1640 cm ^-1 . Dialdimine A-1 has an amine value of 381 mg KO
H / g and was a yellow liquid at room temperature.

Synthetic Example 2 In Synthetic Example 1, the 2,5-isomer of about 60 is used as the amine.
%, And diaminomethylbicyclo [2.2.1] heptane, which is a mixture of about 40% of 2,6-isomer, was treated in the same manner as in Synthesis Example 1 except that benzaldehyde was used as the aldehyde. Amine value 337mgK
OH / g) was obtained.

Synthesis Example 3 In Synthesis Example 1, polyoxypropylene triamine (Texaco Chemical Com) was used as the amine.
manufactured by Pany, trademark: JEFFAMINE T-403,
The molecular weight of 440) was treated in the same manner as in Synthesis Example 1 except that p-isopropylbenzaldehyde was used as the aldehyde, and trialdimine A-3 (amine value: 304 mgKO) was used.
H / g) was obtained.

Synthesis Example of Polyurethane Prepolymer Having Isocyanate Group Synthesis Example 4 147 parts of 2,4-tolylene diisocyanate was used as a diisocyanate, and reacted with 853 parts of polyoxypropylenetriol (molecular weight 3000) at 100 ° C. for 10 hours. A prepolymer was obtained. The terminal NCO group was 3.5% by weight, and the viscosity was 12,000 cps / 25 ° C.

Production Example of Isocyanate Composition Polyurethane prepolymer having an isocyanate group and polyaldimine were mixed in the composition shown in Table 1 to obtain an isocyanate composition. This isocyanate composition was stored in a closed container to shield it from moisture in the air.

Preparation of Acid Solution An organic acid and a solvent were mixed in the composition shown in Table 1 to obtain an acid solution. Evaluation of curability A mixture of an isocyanate composition and an acid solution is 50 mm x
It was cast in a mold of 50 mm × 10 mm, and after 24 hours, it was demolded and the thickness of the cured portion was measured.

Example 1 An isocyanate composition containing 300 parts of a prepolymer and 36 parts of dialdimine (A-1) was placed in a 1-liter poly container, and then an acid solution containing 30 parts of toluene and 1.6 parts of octylic acid was added. Charged. These were mixed with a stirrer, cast into a mold, and allowed to stand in a thermo-hygrostat at 5 ° C. and a relative humidity of 50%. After 24 hours, the mold was released from the mold and the thickness of the cured portion was measured. As a result, as shown in Table 1, the composition has a larger cured thickness and excellent curability as compared with the composition not mixed with the acid solution. It was Further, the inside of the cured product was observed, but no foaming was observed.

Examples 2 to 6 Examples 2 to 6 were carried out according to Example 1 with the formulations shown in Table 1. The results are shown in Table 1, and in any of the formulations, curability was excellent, and no foaming was observed inside the cured product.

Comparative Example 1 An isocyanate composition consisting of 300 parts of prepolymer and 36 parts of dialdimine (A-1) was cast in a mold and left in a thermo-hygrostat at 5 ° C. and 50% relative humidity. After 24 hours, the mold was removed from the mold and the thickness of the cured portion was measured. As shown in Table 1, the cured thickness was very thin and the curability was poor.

Comparative Examples 2 to 3 Comparative Examples 2 to 3 were carried out according to Comparative Example 1 with the formulations shown in Table 1. As a result, as shown in Table 1, the cured thickness was very thin and the curability was poor.

[0028]

[Table 1]

[0029]

EFFECTS OF THE INVENTION According to the curing method of the present invention, by mixing an appropriate amount of acid into an isocyanate composition immediately before construction, a cured product having excellent curability even under a low temperature and low humidity environment and having no foaming can be obtained. can get.

Claims (1)

[Claims] 1. A polyurethane prepolymer having an isocyanate group and the following general formula (I) (Chemical formula 1): Y-(-N = CH-X) n (I) (wherein X is a carbon number) 6 to 15 aryl group, Y is a divalent or trivalent hydrocarbon group having 2 to 15 carbon atoms or a divalent or trivalent polyoxyalkylene group having a molecular weight of 70 to 6000, and n is 2 or 3 The method for mixing an isocyanate composition containing a polyaldimine represented by the formula) with an organic acid and curing the mixture.