JP3111103B2 - Process for producing isocyanurate group-containing polyisocyanate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a polyisocyanate containing an isocyanurate group, and more particularly to a method 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 are excellent in weather resistance, heat resistance, chemical resistance and the like, and are used as raw materials for polyurethanes such as paints, adhesives, elastomers, artificial leathers and foams. . As a production method, a method of trimerizing monomeric diisocyanate in the presence of a catalyst and terminating the reaction with an acidic substance such as hydrochloric acid, phosphoric acid, sulfuric acid, dichloroacetic acid, trichloroacetic acid, benzoyl chloride, acetyl chloride, and benzenesulfonic acid. It has been known. (For example, JP-A-3-93825,
JP-A-2-258771, JP-A-2-107337
No., JP-A-2-11554, JP-A-2-3682,
JP-A-2-250872, JP-A-2-32068,
JP-A-2-64454, JP-A-1-297420, JP-A-1-149821, JP-A-63-57577,
JP-A-61-129173, JP-A-61-11137
No. 1, JP-A-60-181114).

However, the conventional catalyst poisoning substances have drawbacks such that suspended solids are generated when the catalyst poisoning substance is added and products are colored. When phosphoric acid or dichloroacetic acid is used, suspended matter is generated at the time of addition, and a filtration step is required. When benzenesulfonic acid is used, the product is colored. Furthermore, in recent years, it has 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 acid phosphate containing an alkyl group such as dibutyl phosphate, an aryl group, or an arylalkyl group as a catalyst poisoning substance. However, turbidity when the product is diluted with a solvent is not a sufficient solution. Further, JP-A-2-42068 proposes a production method in which silicate is added and a catalyst is adsorbed as a production method that does not cause turbidity during solvent dilution. However, it is necessary to filter the silicate adsorbed with the catalyst. There is.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a polyisocyanate having an isocyanurate ring which does not generate suspended matters and does not produce 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-mentioned problems by using an acidic phosphoric acid ester containing an alkoxy group as a catalyst poisoning substance. Reached. That is, the present invention is selected from monomeric diisocyanates and preurethanation products of monomeric diisocyanates and 1-3 functional alcohols in the presence of a tertiary amine or quaternary ammonium salt. Performing a trimerization reaction of a part of isocyanate groups of at least one isocyanate compound and terminating the reaction with a catalyst poisoning substance. A process for producing an isocyanurate group-containing polyisocyanate, which is used as a catalyst poisoning substance.

The isocyanate compound used in the present invention is
These are monomeric diisocyanates such as aliphatic isocyanates and aromatic isocyanates, and preurethanation products of these monomeric diisocyanates with 1-3-functional alcohols. Examples of aliphatic diisocyanates include hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), dicyclohexylmethane diisocyanate (hydrogenated MDI), hydrogenated xylylene diisocyanate (hydrogenated XDI) and 2,4,4 (or 2,4).
2,4) -trimethylhexamethylene diisocyanate (TMDI). Examples of aromatic diisocyanates include
Tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), toluidine diisocyanate (TODI), xylylene diisocyanate (X
DI) and naphthalene diisocyanate (NDI).

[0007] These monomeric diisocyanates are arbitrarily selected depending on the purpose of use of the final product, but aliphatic diisocyanates are particularly preferred when non-yellowing is required. Examples of the 1-3-functional alcohol include those having 1 to 1 carbon atoms such as methanol, ethanol, and isopropanol .
10 linear or branched aliphatic monohydric alcohols, ethylene glycol, propylene glycol,
Lower aliphatic polyhydric alcohols such as butanediol, glycerin and 1,2,6-hexanetriol; and polyester polyols and polyether polyols having a molecular weight of about 200 to 10,000.

[0008] The isocyanate compound to be subjected to the trimerization reaction may be a mixture of at least two or more of the above-mentioned isocyanate compounds. The tertiary amine and quaternary ammonium salt used as a catalyst in the trimerization reaction may be any of known ones. 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% based on the monomer diisocyanate.

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

As the catalyst poisoning substance, an alkoxy group-containing acidic phosphate is used. The alkoxy phosphate containing an alkoxy group is a compound shown in Chemical formula 1.

[0011]

Embedded image

Examples of the acidic phosphoric acid ester containing an alkoxy group include methoxymethyl phosphate, dimethoxymethyl phosphate, ethoxymethyl phosphate, diethoxymethyl phosphate, propoxymethyl phosphate,
Dipropoxymethyl phosphate, butoxymethyl phosphate, dibutoxymethyl phosphate, butoxyethyl phosphate and 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 a solvent is used, a solvent which does not have a reaction activity for isocyanate groups should be selected. The reaction temperature is usually 20 to 160 ° C., preferably 40
~ 120 ° C.

The progress of the reaction can be monitored by measuring the NCO% of the reaction solution, measuring the infrared spectrum, measuring the refractive index, and the like. If the conversion reaction to isocyanurate proceeds too much, pentamerization and heptamerization occur partially with trimerization, and the viscosity of the product increases.
It is preferably carried out until it reaches 70%, preferably 10-60%.

After terminating 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]

The present invention will be described more specifically with reference to the following examples. However, the present invention is not limited to these. The evaluation in the examples was performed by the following method. Presence / absence of suspended matter: Observed visually Visual turbidity at the time of solvent dilution: After dilution to a solid content of 30% in ethyl acetate, an ultraviolet-visible spectrophotometer (Shimadzu Corporation, UV-
Wavelength 550 with reference to ethyl acetate at 160
Measure absorbance at nm and photometric length 20 mm.

[0017]

Example 1 A glass four-necked flask equipped with a thermometer, a stirrer and a nitrogen sealed tube was charged with 1,000 g of hexamethylene diisocyanate as a monomeric diisocyanate, and the air in the flask was replaced with nitrogen. Heat to 60 ° C. while 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 became 20% by the measurement of 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 the reaction solution by using a falling thin film distillation apparatus.

[0018]

Example 2 Example 1 was repeated except that monobutoxyethyl phosphate was used instead of dibutoxyethyl phosphate.
Was performed in the same manner as described above.

[0019]

Example 3 A glass four-necked flask equipped with a thermometer, a stirrer, and a nitrogen sealed tube was charged with 1,000 g of tolylene diisocyanate and 50 g of butanediol as monomeric diisocyanates. 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 became 8%, 3.0 g of propoxyethyl phosphate was added to stop the reaction.

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

[0021]

Comparative Example 1 Instead of dibutoxyethyl phosphate,
The procedure was performed in the same manner as in Example 1 except that 0.3 g of phosphoric acid was used.

[0022]

Comparative Example 2 Instead of dibutoxyethyl phosphate,
The procedure was performed in the same manner as in Example 1 except that 0.4 g of dibutyl phosphate was used.

[0023]

Comparative Example 3 Instead of dibutoxyethyl phosphate,
The procedure was performed in the same manner as in Example 1 except that 0.3 g of dipropyl phosphate was used.

[0024]

Comparative Example 4 Instead of dibutoxyethyl phosphate,
The reaction was carried out in the same manner as in Example 1 except that 1.0 g of tributoxyethyl phosphate was used, but the reaction was not stopped. Table 1 shows the measurement results of the polyisocyanates obtained in the above examples.

[0025]

[Table 1]

[0026]

According to the present invention, it is possible to produce a polyisocyanate having an isocyanurate ring which does not generate suspended matters and does not generate mist when diluted with a solvent.

────────────────────────────────────────────────── ─── Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C07D 251/34 C08G 18/16 C08G 18/79 CA (STN) REGISTRY (STN)

Claims (1)

(57) [Claims] 1. A monomer diisocyanate and a pre-urethane reaction product of a monomeric diisocyanate and a 1-3-functional alcohol in the presence of a tertiary amine or a quaternary ammonium salt. Performing a trimerization reaction of a part of isocyanate groups of at least one isocyanate compound and terminating the reaction with a catalyst poisoning substance. A method for producing an isocyanurate group-containing polyisocyanate, which is used as a catalyst poisoning substance.