JPH05170748A - Production of polyisocyanate containing isocyanurate group - Google Patents

Abstract

PURPOSE:To obtain the subject compound which generates no floating matter and causes no turbidness on dilution with a solvent by effecting trimerization reaction of a diisocyanate monomer and an isocyanate compound and terminating the reaction with a poisoned catalyst. CONSTITUTION:In the presence of a tertiary amine or a quaternary ammonium salt such as tetramethylammonium caprate, trimerization reaction is carried out between a diisocyanate monomer and a part of the isocyanate group in at least one isocyanate compound selected from the preliminarily urethanized product from a diisocyanate monomer and mono- to trifunctional alcohol. Then, an acidic phosphoric acid ester containing alkoxy groups is used as a catalytic poison to stop the reaction and obtain the subject compound. The polyisocyanate having an isocyanurate ring in the molecule has excellent resistance to weather, heat, chemicals and so forth and is useful as a starting substance for coating, adhesive, elastomer, artificial leather, foam or the like.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a process for producing an isocyanurate group-containing polyisocyanate, and more particularly to a process for producing a polyisocyanate having an isocyanurate ring having good solvent solubility.

[0002]

2. Description of the Related Art Polyisocyanates having an isocyanurate ring in the molecule have excellent weather resistance, heat resistance and chemical resistance and are used as raw materials for polyurethanes such as paints, adhesives, elastomers, artificial leather and foams. .. As a production method, a method in which monomer diisocyanate is trimerized in the presence of a catalyst and the reaction is stopped by an acidic substance such as hydrochloric acid, phosphoric acid, sulfuric acid, dichloroacetic acid, trichloroacetic acid, benzoyl chloride, acetyl chloride or benzenesulfonic acid. It has been known. (For example, JP-A-3-93825,
JP-A-2-258771, JP-A-2-107337
No. 2, Japanese Patent Application Laid-Open No. 2-11554, Japanese Patent Application Laid-Open No. 2-3682,
JP-A-2-250872, JP-A-2-32068,
JP-A No. 2-6454, JP-A No. 1-297420, JP-A No. 1-149821, and JP-A No. 63-57577,
JP 61-129173 A, JP 61-11137 A
No. 1, JP-A-60-181114).

However, the conventional catalyst poisoning substances have drawbacks such that suspended matter is generated when the catalyst poisoning substance is added and the product is colored. When phosphoric acid or dichloroacetic acid is used, a floating substance is generated at the time of addition and a filtration step is required, and when benzenesulfonic acid is used, the product is colored. Further, in recent years, it has also been used as a raw material for optical materials such as plastic lenses, and turbidity when diluted with a solvent has become a problem. Japanese Patent Application Laid-Open No. 2-6480 proposes to use an acidic phosphoric acid ester containing an alkyl group, an aryl group, or an arylalkyl group, such as dibutyl phosphate, as a catalyst poisoning substance, but it is effective in generating suspended matter. However, it is not a sufficient solution for turbidity when the product is diluted with a solvent. Further, Japanese Patent Application Laid-Open No. 2-42068 proposes a manufacturing method in which a silicate is added to adsorb a catalyst as a manufacturing method in which turbidity does not occur when a solvent is diluted, but it is necessary to filter the silicate adsorbing the catalyst. There is.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a polyisocyanate having an isocyanurate ring that does not generate suspended solids and does not cause turbidity when diluted with a solvent.

[0005]

As a result of intensive studies and studies, the present inventors have found a method for solving the above problems by using an alkoxy group-containing acidic phosphoric acid ester as a catalyst poisoning substance, and found the present invention. I arrived. That is, the present invention is selected from a monomer diisocyanate and a pre-urethanization reaction product of the monomer diisocyanate and a 1 to 3 functional alcohol in the presence of a tertiary amine or a quaternary ammonium salt. In a process for producing an isocyanurate group-containing polyisocyanate, which comprises performing a trimerization reaction of a part of an isocyanate group of at least one isocyanate compound and stopping the reaction by a catalyst poisoning substance, an alkoxy group-containing acidic phosphate ester A method for producing an isocyanurate group-containing polyisocyanate, which is characterized in that it is used as a catalyst poisoning substance.

The isocyanate compound used in the present invention is
It is a monomer diisocyanate such as an aliphatic isocyanate and an aromatic isocyanate, and a pre-urethanization reaction product of these monomer diisocyanates and a 1 to 3 functional alcohol. Examples of aliphatic diisocyanates are hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), dicyclohexylmethane diisocyanate (hydrogenated MDI), hydrogenated xylylene diisocyanate (hydrogenated XDI) and 2,4,4 (or 2,
2,4) -trimethylhexamethylene diisocyanate (TMDI). Examples of aromatic diisocyanates are:
Tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), toluidine diisocyanate (TODI), xylylene diisocyanate (X
DI) and naphthalene diisocyanate (NDI).

These monomeric diisocyanates are arbitrarily selected according to the intended use of the final product, but aliphatic diisocyanates are preferred especially when non-yellowing is required. Examples of the monofunctional to trifunctional alcohols include lower aliphatic monohydric alcohols such as methanol, ethanol and isopropanol, as well as ethylene glycol, prepylene glycol, butanediol, glycerin, 1, 2,
Examples include lower aliphatic polyhydric alcohols such as 6-hexanetriol, polyester polyols and polyether polyols having a molecular weight of about 200 to 10,000.

The isocyanate compound for the trimerization reaction may be a mixture of at least two kinds of the above-exemplified isocyanate compounds. Any known tertiary amine or quaternary ammonium salt may be used as a catalyst in the trimerization reaction. Examples of tertiary amines are dialkylaminoalkylphenols, trialkylamines, tetraalkylalkylenediamines.
Examples of quaternary ammonium salts are tetramethylammonium hydroxide, trimethyl-2-hydroxyethylammonium hydroxide, tetramethylammonium capryate. The catalyst concentration varies depending on the type of catalyst used and the reaction temperature, but is usually selected from the range of 10 ppm to 1% with respect to the monomer diisocyanate.

Regarding the catalyst, for example, JP-A-3-93
825, JP-A-2-250872, JP-A-2-32
068, JP-A No. 2-6454, and JP-A No. 1-2974.
No. 20, JP-A-149821, JP-A-63-575.
77, JP 61-129173 A, JP 61-1 A.
11371, JP-A-60-181114, etc.

An alkoxy group-containing acidic phosphoric acid ester is used as the catalyst poisoning substance. The alkoxy group-containing acidic phosphoric acid ester is the compound shown in Chemical formula 1.

[0011]

[Chemical 1]

Examples of the alkoxy group-containing acidic phosphoric acid ester include methoxymethyl phosphate, dimethoxymethyl phosphate, ethoxymethyl phosphate, diethoxymethyl phosphate, propoxymethyl phosphate,
These are dipropoxymethyl phosphate, butoxymethyl phosphate, dibutoxymethyl phosphate, butoxyethyl phosphate, dibutoxyethyl phosphate.

The amount of the catalyst poisoning substance used is preferably 0.4 to 10 equivalents, more preferably 0.6 to 5 equivalents, per equivalent of the catalyst. The reaction may or may not use a solvent. When using a solvent, it is of course necessary to select a solvent having no reaction activity with respect to isocyanate groups. The reaction temperature is usually 20 to 160 ° C., preferably 40.
It is selected from the range of 120 ° C.

The progress of the reaction can be traced by NCO% measurement of the reaction solution, infrared spectroscopy measurement, refractive index measurement and the like. If the conversion reaction to isocyanurate proceeds too much, pentamerization and heptamerization partially occur together with trimerization to increase the viscosity of the product.
It is preferable to carry out until it reaches 70%, preferably 10 to 60%.

After stopping the reaction, excess monomeric diisocyanate and solvent are removed to obtain a product. The removal of the monomer diisocyanate and the solvent is performed by, for example, a thin film distillation method or a solvent extraction method.

[0016]

EXAMPLES The present invention will be described in more detail with reference to the following examples. However, the present invention is not limited to these. The evaluation in the examples was carried out by the method described below. Presence or absence of suspended matter: Visual observation Turbidity when diluted with solvent: Ultraviolet-visible spectrophotometer (Shimadzu Corporation, UV-
Wavelength 550 with ethyl acetate as reference at 160
Measure the absorbance at nm and photometric length of 20 mm.

[0017]

Example 1 A glass four-necked flask equipped with a thermometer, a stirrer, and a nitrogen seal tube was charged with 1000 g of hexamethylene diisocyanate as a monomeric diisocyanate, the air in the flask was replaced with nitrogen, and the mixture was stirred. Heated to 60 ° C. with stirring. As a trimerization catalyst, 0.2 g of tetramethylammonium capryate was added in portions.
The reaction was continued at 60 ° C., and when the conversion of hexamethylene diisocyanate reached 20% by measuring the refractive index of the reaction solution, 0.5 g of dibutoxyethyl phosphate was added to stop the reaction. Unreacted hexamethylene diisocyanate was removed and recovered from this reaction solution using a falling film distillation apparatus.

[0018]

Example 2 Example 1 except that monobutoxyethyl phosphate is used instead of dibutoxyethyl phosphate.
I went in the same way.

[0019]

Example 3 A glass four-necked flask equipped with a thermometer, a stirrer, and a nitrogen seal tube was charged with 1000 g of tolylene diisocyanate as monomer diisocyanate and 50 g of butanediol, and the air in the flask was filled with nitrogen. After substitution, the reaction was carried out with stirring. Butyl acetate 1000g
Then, 5 g of tetramethylethylenediamine was added as a trimerization catalyst, and when the NCO content of the reaction solution reached 8%, 3.0 g of propoxyethyl phosphate was added to stop the reaction.

From the reaction solution, unreacted tolylene diisocyanate and butyl acetate were removed and recovered using a falling film distillation apparatus.

[0021]

Comparative Example 1 Instead of dibutoxyethyl phosphate,
Example 1 was repeated except that 0.3 g of phosphoric acid was used.

[0022]

Comparative Example 2 Instead of dibutoxyethyl phosphate,
Example 1 was repeated except that 0.4 g of dibutyl phosphate was used.

[0023]

Comparative Example 3 Instead of dibutoxyethyl phosphate,
Example 1 was repeated except that 0.3 g of dipropyl phosphate was used.

[0024]

Comparative Example 4 Instead of dibutoxyethyl phosphate,
Example 1 was repeated except that 1.0 g of tributoxyethyl phosphate was used, but the reaction did not stop. Table 1 shows the measurement results of the polyisocyanate obtained in the above examples.

[0025]

[Table 1]

[0026]

EFFECT OF THE INVENTION It is possible to produce a polyisocyanate having an isocyanurate ring which does not generate floating substances and does not cause turbidity even when diluted with a solvent.

Claims (1)

[Claims] 1. A monomer diisocyanate in the presence of a tertiary amine or a quaternary ammonium salt, and a pre-urethanization reaction product of the monomer diisocyanate and a 1-3 functional alcohol. In a process for producing an isocyanurate group-containing polyisocyanate, which comprises performing a trimerization reaction of a part of an isocyanate group of at least one isocyanate compound and stopping the reaction by a catalyst poisoning substance, an alkoxy group-containing acidic phosphate ester A method for producing a polyisocyanate containing an isocyanurate group, which is used as a catalyst poisoning substance.