JPH0725976A - Method for curing isocyanate composition containing latent curing agent - Google Patents

Abstract

PURPOSE:To obtain a cured product, rapidly curable and having uniform physical properties without foaming by mixing water with a composition containing a specific latent curing agent and an isocyanate group-containing polyurethane prepolymer. CONSTITUTION:Water is mixed with an isocyanate composition containing (A) a latent curing agent capable of producing an amine by the hydrolysis {preferably a polyaldimine expressed by the formula Y-(-N=CH-X)n (X is 6-15C aryl; Y is 2-15C bi- or trivalent hydrocarbon or bi- or trivalent polyoxyalkylene having 70-6000 molecular weight; n is 2 or 3), e.g. an enamine or a polyketimine} and (B) a polyurethane prepolymer having isocyanate group to cure the isocyanate composition. Furthermore, the water is mixed so as to provide 0.1-10, preferably 0.3-5.0 ratio of the number of amino group equiv. of the polyamine produced in hydrolyzing the component (A) to the number of mol of the water.

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 with water.

[0002]

2. Description of the Related Art Polyurethane resins are excellent in various properties such as rubber elasticity, abrasion resistance and durability, so that they have recently been used as paints, floor materials, waterproof materials, adhesives, potting materials, wall materials and sealing materials. Especially used. The method for producing these polyurethane resins is a one-pack type in which the terminal NCO group of the polyurethane prepolymer is cured with water in the atmosphere after the construction, and a curing agent containing a main agent containing the polyurethane prepolymer and polyols is constructed. 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 the components 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. A composition containing a latent curing agent has been devised as a method for improving this drawback. These do not cause deterioration of cured physical properties or curing defects, but since they gradually cure from the surface after construction, it takes a long time to completely cure to the inside and the coating thickness has a limit. .

[0004]

There is a strong demand for a method for curing an isocyanate composition that overcomes the above problems, that is, the curing rate is high, the cured product does not cause foaming, and uniform physical properties are always obtained. It was rare.

[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, by adding and mixing an appropriate amount of water immediately before application to an isocyanate composition containing a latent curing agent that forms an amine by hydrolysis and a polyurethane prepolymer having an isocyanate group, the curability is improved. Is improved, and uniform physical properties of the cured product can be obtained. That is, the present invention is (1) a method in which water is mixed with an isocyanate composition containing a latent curing agent that produces an amine by hydrolysis and a polyurethane prepolymer having an isocyanate group, and the mixture is cured. The latent curing agent that produces an amine by decomposition is represented by the following general formula (1) Y-(-N = CH-X) n --- (1) (wherein X represents an aryl group having 6 to 15 carbon atoms). , 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.). Including being a polyaldimine.

In the present invention, the isocyanate composition contains a latent curing agent which produces an amine by hydrolysis and a polyurethane prepolymer having an isocyanate group. Enamine (UK Patent No. 157566) is used as a latent curing agent that produces an amine by hydrolysis.
6), polyaldimines or polyketimines (UK patent 1
064481, German Patent 3133769, Japanese Patent Laid-Open No. 2-2
83710, JP-A-4-279620), β-lactam (JP-A-2-168) and the like.

The following general formula (1) Y-(-N = CH-X) n --- (1) (wherein, X is an aryl group having 6 to 15 carbon atoms, Y is a carbon atom)
Number 2 to 15 divalent or trivalent hydrocarbon group or molecule
Amount of 70-6000 and divalent or trivalent polyoxya
The alkylene group represents n or 2 or 3. )
The polyamines used in the production of realdimine include
1) ethylenediamine, 1,3-diaminopropane,
Tetramethylenediamine, hexamethylenediamine,
Ptamethylenediamine, Octamethylenediamine, Deca
Aliphatic diamines such as methylenediamine, 4,4'-di
Aminodicyclohexylmethane, isophoronediamine,
Bisaminomethylcyclohexane, 2,5- or 2,6
-Diaminomethylbicyclo [2,2,1] heptane, di
Aminocyclohexane, 3 (4), 8 (9) -bis (a)
Minomethyl) -tricyclo [5.2.1.0] ^2.6] Deca
Alicyclic diamines such as diamine, diaminodiphenylmethane, diamine
Amino diphenyl ether, xylylenediamine, fe
Nylenediamine, 3,5-diethyltoluene-2,
Aromatic diamines such as 4- or 2,6-diamine, water, and
Propylene glycol, propylene glycol, etc.
Addition polymerization of ethylene oxide and / or ethylene oxide
Of polyoxyalkylene glycols obtained by
Polyoxyalkyl obtained by converting sil group into amino group
Diamines such as diamine, 2) 1,3,5-tris
(Aminomethyl) benzene, 1,3,5-tris (ami)
(Trimethyl) cyclohexane and other triamines, glycerin
Propylene oxide, etc.
And / or poly (ethylene oxide)
The hydroxyl group of oxyalkylene triols is
Of polyoxyalkylene triami
Triamine, etc.

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

The polyaldimine represented by the above general formula (1) is obtained by reacting the above polyamine and the above aldehyde with a solvent such as toluene or xylene under an acid catalyst.
A dehydration reaction is carried out by azeotropic distillation, and the reaction is continued in 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, a known polyol, a known polyamine or the like, and a known compound having two or more active hydrogens in one molecule. The reaction was performed so that
That is, 1 of polyisocyanate and a compound having active hydrogen
It is produced by reacting at 00 ° C. for several hours. The isocyanate group content of the polyurethane prepolymer is 0.3 to 20.
0% by weight is preferable, and a particularly preferable range is 0.5 to 15.
It is 0% by weight.

Known polyisocyanates are: 1) Tolylene diisocyanate (including various mixtures of isomers),
Diphenylmethane diisocyanate (including various mixtures of isomers), 3.3'-dimethyl-4.4'-biphenylenediisocyanate, 1.4-phenylenediisocyanate, xylylenediisocyanate, tetramethylxylylenediisocyanate, naphthylenediisocyanate, dicyclohexylmethane -4.4'-diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, hydrogenated xylene diisocyanate,
1,4-cyclohexyl diisocyanate, 1-methyl-2,4-diisocyanato-cyclohexane, 2.4.
Diisocyanates such as 4-trimethyl-1,6-diisocyanato-hexane, 2) Triisocyanates such as 4,4 ′, 4 ″ -triphenylmethane triisocyanate and tris (4-phenylisocyanato) thiophosphate, 3) The above isocyanates Urethane-modified products,
Isocyanurate modified product, Carbodiimide modified product,
Polyfunctional isocyanates such as biuret-modified products and crude tolylene diisocyanate and polymethylene polyphenyl isocyanate.

Known compounds having two or more active hydrogens in one molecule include two or more hydroxyl groups, one or more amino groups, two or more mercapto groups, or a hydroxyl group and an amino group. A compound having, or a compound having a hydroxyl group and a mercapto group, for example,
Polyhydric alcohols such as water, ethylene glycol, propylene glycol, glycerin, trimethylolpropane, pentaerythritol, sorbitol, sucrose or aniline, tolylenediamine, aromatic amines such as p, p'-diamino-diphenylmethane, ethylenediamine, ethanol Obtained by addition-polymerizing propylene oxide or propylene oxide and ethylene oxide to an aliphatic amine such as amine, diethanolamine or the like, or an alkanolamine and a compound having two or more active hydrogens in the molecule or a mixture of these compounds. Polyether polyols, polyether polyamines obtained by converting the hydroxyl groups of the polyether polyols into amino groups, polytetramethylene ether polyols, poly 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. , Compounds obtained by copolymerizing known ethylenically unsaturated monomers having one or more active hydrogens in one molecule, and ethers having a mercapto group.

The isocyanate composition of the present invention comprises a latent curing agent and a polyurethane prepolymer having an isocyanate group, and the number of amino groups of polyamine produced by hydrolysis of the latent curing agent and the polyurethane prepolymer having an isocyanate group. It is obtained by mixing at a ratio of 0.5 to 2.0, preferably 0.7 to 1.5, with the number of isocyanate groups contained in. The isocyanate composition includes a filler, a thixotropy-imparting agent for adjusting viscosity, resin physical properties, and resistance, depending on applications such as paints, flooring materials, waterproofing materials, adhesives, potting materials, wall materials, and sealing materials. , A plasticizer, a solvent, an adhesion-imparting agent, a colorant, a stabilizer and the like can be mixed and used.

The water used in the present invention may be ordinary tap water or the like, and no special treatment is required. The mixing of the isocyanate composition and water can be carried out by using a collision mixing type spray device, whether it is stirred in a container with an electric mixer which is generally used, manually stirred, or mixed with a static mixer. Also, the method is not limited to these methods. Suitable solvents for efficiently mixing the isocyanate composition with water, such as acetone, methyl ethyl ketone, ketones such as cyclohexanone, tetrahydrofuran, 1,4-dioxane, ethers such as ethylene glycol diethyl ether, methyl formate, Ethyl formate,
Methyl acetate, ethyl acetate, glycol carbonate, esters such as ethylene glycol monoethyl ether acetate and glycol diacetate, other acetonitrile, dimethylformamide, pyridine and the like may be mixed with water. The mixing amount of water to the isocyanate composition is such that the ratio of the number of equivalents of amino groups of the polyamine produced by hydrolysis of the latent curing agent to the number of moles of water is 0.1 to 1.
The ratio is 0, preferably 0.3 to 5.0.

In order to accelerate the curing of the isocyanate composition, a hydrolysis catalyst for the latent curing agent, for example, carboxylic acid, sulfonic acid, phosphoric acid, phosphoric acid ester and the like may be added to water and used. The amount added varies depending on the target curing speed, but is generally 10 PHR for the isocyanate composition.
It is preferably 5 PHR or less.

In the present invention, a polyurethane composition containing a latent curing agent capable of forming an amine by hydrolysis and a polyurethane prepolymer having an isocyanate group is rapidly cured by mixing with water and is always free from foaming. A cured product having uniform physical properties can be obtained.

[0017]

EXAMPLES Examples of the present invention will be described below. In the examples, "part" means "part by weight".

Synthesis Example of Latent Curing Agent Synthesis Example 1 88 parts of tetramethylenediamine (2.0 parts) was placed in a reaction vessel equipped with a stirrer, a thermometer, a dropping funnel, and a water separator.
Equivalent), 0.1 part of formic acid and 500 parts of toluene were charged and mixed at room temperature under a nitrogen stream. About 10 minutes later, 300 parts (2.5 equivalents) of p-tolualdehyde was added to about 3 from the dropping funnel.
It was dripped in 0 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. Then, 1mmHg with a vacuum pump
The pressure was reduced to, 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 had an amine value of 381 mgKOH / g and was a yellow liquid at room temperature. Synthetic Example 2 In Synthetic Example 1, 2,5-isomer of about 60 was used as the amine.
Of diaminomethylbicyclo [2,2,1] heptane, which is a mixture of 40% and 2,40-isomer of about 40%, was treated in the same manner as in Synthesis Example 1 except that benzaldehyde was used as the aldehyde. (Amine number 337 mg
KOH / g) was obtained. Synthesis Example 3 In Synthesis Example 1, polyoxypropylenetriamine (Texaco Chemical Com) was used as the amine.
manufactured by Pany, trademark: JEFFAMINE T-403,
A molecular weight of 440) was treated in the same manner as in Synthesis Example 1 except that p-isopropylbenzaldehyde was used as the aldehyde to give trialdimine A-3 (amine value: 304 mgK).
OH / g) was obtained. Synthesis Example 4 In Synthesis Example 1, the aromatic polyamine MD is used as the amine.
A-150 (Polymeric methylene dianiline manufactured by Mitsui Toatsu Chemicals, Inc.) was treated in the same manner as in Synthesis Example 1 except that trimethylacetaldehyde was used as the aldehyde, and polyaldimine A-4 (amine value 299 mgKOH).
/ G) was obtained. Synthesis Example 5 1,4-bis {3,3-dimethyl-2-oxo-1- [3- (2- (2-ethoxyethoxy) ethoxycarbonylaminomethyl) benzyl] according to JP-A-2-168.
Azetidin-4-yl} piperazine was synthesized to obtain β-lactam A-5 (amine value 133 mgKOH / g).

Synthetic Example of Polyurethane Prepolymer Having Isocyanate Group Synthetic Example 6 1,000 parts of 2,4-tolylene diisocyanate was used as diisocyanate and reacted with 3000 parts of polyoxypropylenetriol (molecular weight 1500) at 100 ° C. for 10 hours. Prepolymer A was obtained. The terminal NCO group was 5.6% by weight, and the viscosity was 19,000 cps / 25 ° C. Synthesis Example 7 Isophorone diisocyanate 2 as diisocyanate
Using 000 parts, a prepolymer B was obtained by reacting with 2500 parts of polyoxypropylene triol (molecular weight 1500) at 100 ° C. for 10 hours. The terminal NCO group is 12.
The viscosity was 1% by weight and the viscosity was 2,200 cps / 25 ° C.

Preparation of Isocyanate Composition A latent curing agent and a polyurethane prepolymer having an isocyanate group were mixed in the composition shown in Table 1 to obtain an isocyanate composition. This isocyanate composition was stored in a closed container in order to shield it from moisture in the air. Preparation of aqueous solution An aqueous solution was obtained by mixing water, a solvent and a hydrolysis catalyst with the composition shown in Table 1. Measurement of Curing Time The curing time is 30 minutes from the time when the mixture of the isocyanate composition and the aqueous solution is cast into a mold of 5 cm × 5 cm × 1 cm with a thickness of 1 cm until the cured product can be released from the mold. I checked each time.

Example 1 An isocyanate composition consisting of 300 parts of prepolymer A and 53 parts of dialdimine (A-1) was charged into a 1 liter poly container, followed by 5 parts of water, 10 parts of acetone and isopropyl acid hydrolysis catalyst. An aqueous solution consisting of 1 part of phosphate (trade name: AP-3, manufactured by Daihachi Chemical Industry Co., Ltd.) was charged. These were mixed with a stirrer and cast into a mold.
The results are shown in Table 1, and the cured product could be demolded in 1 hour. After demolding, the cured product was cut and the inside was observed. As a result, it was uniformly cured and no foaming was observed.

Examples 2 to 5 Examples 2 to 5 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, curing was fast, the inside of the cured product was uniformly cured, and no foaming was observed.

Comparative Example 1 300 parts of prepolymer A, dialdimine (A-1) 53
The isocyanate composition consisting of parts was cast into a mold. The results are shown in Table 1, and even after 24 hours, the surface of the isocyanate composition was cured without being cured, and the inside was completely uncured.

Comparative Example 2 The same treatment as in Example 1 was carried out except that dialdimine was not used in Example 1. The results are shown in Table 1,
It was violently foaming.

Comparative Example 3 An isocyanate composition consisting of 300 parts of prepolymer B and 145 parts of trialdimine (A-3) was charged in a 1-liter poly container, followed by 15 parts of acetone, (AP-3).
A solution consisting of 3 parts was charged. When these were mixed with a stirrer and cast into a mold, as shown in Table 1, even after 24 hours, only the surface of the isocyanate composition was cured, and the inside was completely uncured. It was

[0026]

[Table 1]

[0027]

According to the curing method of the present invention, an isocyanate composition is mixed with an appropriate amount of water to cure rapidly, and a cured product having uniform physical properties without foaming can be obtained.

Claims (2)

[Claims] 1. A curing method in which water is mixed with an isocyanate composition containing a latent curing agent capable of generating an amine by hydrolysis and a polyurethane prepolymer having an isocyanate group and cured. 2. A latent curing agent which produces an amine by hydrolysis is represented by the following general formula (1) Y-(-N = CH-X) n --- (1) (wherein X represents 6 carbon atoms). To 15 aryl groups, 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 curing method according to claim 1, which is a polyaldimine represented by the formula (1).