JPH075574B2 - Method for producing isocyanurate cyclic structure substance - Google Patents

Description

TECHNICAL FIELD The present invention relates to a novel method for producing isocyanurate cyclic structure substances useful for producing lacquers and foams.

[Conventional technology]

The isocyanurate cyclic structure substance is usually formed by trimerizing an organic isocyanate in the presence of a catalyst.
Trimerization catalysts include JHSaun-ders and KCFrisc
h: Polyurethanes, Chemistry and Technology (1962) p.
94, organic strong bases such as alkali acid salts of carboxylic acids, alkali metal ferrites, alkali metal carbonates, tertiary amines, tertiary phosphines and N or P onium compounds, and heterocyclic compounds of these elements. ing. In addition, as shown in JP-A-52-18798 and JP-A-59-36122, a reaction product of a Mannich base or a tertiary amine with an alkyl ester of phosphoric acid, phosphorous acid or phosphonic acid is used. It is known.

[Problems to be solved by the invention]

However, the conventional trimerization catalysts have a drawback that the reaction selectivity is poor and that reactions other than trimerization also come into contact with each other and easily give highly crosslinked reaction products. The present inventor has found that this problem can be solved by using potassium fluoride as a catalyst, but the reaction rate is slightly slower than in the case of using a tertiary amine or an alkali metal alcoholate as a catalyst. Was desired.

The present invention aims to solve the above-mentioned problems in the production of organic isocyanate trimers.

[Means for solving problems]

The present invention, when trimerizing the organic isocyanate,
With potassium fluoride as a catalyst, the following (i) to (ii
A method for producing an isocyanurate cyclic structure material, which comprises using one kind or a combination of two or more kinds of compounds selected from i).

(I) Polyethylene oxide compound (ii) Quaternary ammonium salt (iii) Phosphonium compound When the present inventor uses potassium fluoride as a catalyst when trimerizing an organic isocyanate, there are problems of coloring and selectivity. However, as a result of further research, when the compounds (i) to (iii), which are known as phase transfer catalysts, are used in combination with potassium fluoride, it is more organic than potassium fluoride alone. The present inventors have found that the trimerization of isocyanate can be dramatically promoted, and have reached the present invention.

The potassium fluoride used in the present invention is in the form of pellets,
Any of various shapes such as powder and flakes can be used.
It may also be supported on a carrier such as Celite or activated carbon. The powdery form is preferable from the viewpoints of easy industrial availability and economy.

As the organic isocyanate of the present invention, any of aliphatic or aromatic mono-, di- or polyisocyanates can be used. Suitable organic isocyanates include aliphatic isocyanates such as methyl isocyanate, n-butyl isocyanate, n-octyl isocyanate, stearyl isocyanate, hexamethylene diisocyanate,
Examples of aromatic isocyanates such as isophorone diisocyanate include phenyl isocyanate, 2,4- and 2,6-tolylene diisocyanate, and diphenylmethane diisocyanate. When a diisocyanate such as 2,4-tolylene diisocyanate having a difference in activity between two isocyanate groups is used, isocyanurate group-containing polyisocyanate in which only half of the starting isocyanate groups participate in the reaction is selectively used. Can be manufactured.

Used in combination with potassium fluoride (i)-(ii
Examples of the compound of i) include the following.

Examples of the polyethylene oxide compound (i) include polyethylene glycols such as polyethylene glycol, polyethylene glycol monomethyl ether and polyethylene glycol dimethyl ether, crown ethers such as dibenzo-18-crown-6 and dicyclohexyl-18-crown-6, for example, Kanto. Cryptands such as C ₁₄ H ₂₈ N ₂ O ₄ or C ₁₆ H ₃₂ N ₂ O ₅ , which are commercially available as “Cryptfix-111” and “Cryptfix-221” manufactured by Kagakusha, (ii) The quaternary ammonium salt is tris (dioxa-3,6-heptyl) amine, benzyltriethylammonium chloride, tetrabutylammonium bromide, and the phosphonium compound of (iii) is trioctylethylphosphonium bromide, tetraphenylphosphonium. Examples thereof include chloride and tetrabutylphosphonium chloride.

The catalyst is used in an amount of 0.0001 to 0.05 parts by weight based on 1 part by weight of the organic isocyanate used.
The compounds (i) to (iii) are 1/100 of potassium fluoride.
A double or 100-fold amount is preferred.

The trimerization reaction is carried out in the presence or absence of a solvent inert to isocyanate. As the solvent, an organic solvent commonly used in the reaction of isocyanate can be used in the present invention. Examples of preferred solvents are ethyl acetate, esters such as butyl acetate, acetone, ketones such as methyl ethyl ketone, benzene, toluene, aromatic substances such as xylene, dimethyl sulfoxide, tetramethyl sulfone, tetrahydrofuran, N-methylpyrrolidone, N. , N-
Dimethylformamide, N, N'-tetramethylurea, 1,3
-Aprotic solvents such as dimethylimidazolidinone can be mentioned.

Since potassium fluoride loses its catalytic activity in the presence of water, it is important to react under non-aqueous conditions.

When a solvent is used, the reaction is carried out by dissolving the organic isocyanate in the solvent and at a temperature from room temperature to about 150 ° C.

The reaction is usually completed in 1 second to several hours. Since potassium fluoride is almost insoluble in the above organic solvents (0.1 g / ml or less), it can be easily recovered by filtration after the reaction. In many cases, using the reaction product containing potassium fluoride as it is does not adversely affect the commercial value of the final product. The obtained trimer can be easily separated and recovered from the solvent by a known method such as filtration and concentration.

When no solvent is used, potassium fluoride is directly dispersed in organic isocyanate, and the above interlayer transfer catalyst is preferably dissolved in organic isocyanate and then added.

In the case of aromatic isocyanate, the reaction can be completed almost instantaneously by appropriately selecting the amount of catalyst and the reaction temperature.

〔The invention's effect〕

The method for producing an organic isocyanate trimer according to the present invention has the following advantages over conventional methods.

The reaction rate is very fast and almost 100% proceeds.

Starting from 2,4-tolylene diisocyanate, 4-
A trimer obtained by reacting only the isocyanate group at the position is quantitatively obtained. Even if the reaction temperature is raised or the reaction time is extended, the isocyanate group at the 2-position no longer self-condenses. Since polynuclear bodies are not formed at all, it has excellent solubility in a solvent.

Since the side reaction hardly occurs, the raw material efficiency is excellent, and the obtained trimer is extremely easy to separate and purify.

Since the amount of the catalyst is extremely small, it is not necessary to separate the catalyst after the reaction and it is economically inexpensive.

〔Example〕

 The present invention will be described below with reference to examples.

Example 1 40 g of 2,4-tolylene diisocyanate and 40 m of potassium fluoride
g and 40 mg of tris [dioxa-3,6-heptyl] amine (TDA-1 manufactured by Rhone-Poulin) were added and the mixture was warmed to 50 ° C. Three
After minutes, the system became very viscous and unstirred, and after 5 minutes solidified white. After cooling, it was pulverized, washed repeatedly with 200 cc of hexane three times, and then vacuum dried at room temperature. The yield was almost quantitative. Elemental analysis value of the reaction product is C: 62.1%,
It was H: 3.4% and N: 16.1%. Infrared absorption spectrum is 2
The absorption of -C = O groups of absorption and 1700 cm ^-1 of the -NCO groups of 250 cm ^-1 shown in almost the same intensity.

Example 2 40 g of 2,4-tolylene diisocyanate and 100 parts of potassium fluoride
mg and Tokyo Kasei Co. 18-crown-6-ether 50 mg were added at room temperature. The reaction system solidified white immediately after the addition of the crown compound. The product was dissolved in butyl acetate and analyzed by the di-n-butylamine method. As a result, the NCO group content was 24.8%, which was very close to the theoretical amount of 24.1% based on the trimer.

In addition, this product shows a melting point of 130-135 ° C.
In contrast to the NCO group content of 15.0%, no clear melting point was shown when heated to 300 ° C.

Comparative Example 1 The reaction was performed in the same manner as in Example 2 except that 50 mg of 18-crown-6-ether was not added. It hardly reacts at room temperature, and after heating at 120 ° C for 3 hours, the unreacted materials are distilled off in a vacuum.
8 g of oligomer was obtained. The isocyanate content of this product was 26.3%, and as a result of analysis by liquid chromatography, it was about 8%.
It contained unreacted raw materials.

Example 3 n-butyl isocyanate 5 ml, N-methylpyrrolidone 50 m
1, 0.2 g of potassium fluoride and 0.1 g of trimethylbenzylammonium chloride were added and the reaction was carried out at 120 ° C. for 4 hours. The system was discharged into 300 cc of water, the oil layer was separated, and extracted repeatedly with water three times to remove the solvent N-methylpyrrolidone. The oil layer was vacuum dried to obtain 2.2 g of product. From elemental analysis and infrared absorption spectrum, it was confirmed to be a cyclic trimer of n-butyl isocyanate.

Example 4 A reaction was carried out in the same manner as in Example 1 except that 0.1 g of tetrabutylphosphonium chloride was used instead of TDA-1 manufactured by Rhone-Poulin. The product was virtually identical to Example 1, although it took 3 hours at 120 ° C. to set.

Claims (1)

[Claims] 1. When the organic isocyanate is trimerized, the following (i) to
A method for producing an isocyanurate cyclic structure substance, which comprises using one kind or a combination of two or more kinds of compounds selected from (iii). (I) Polyethylene oxide compound (ii) Quaternary ammonium salt (iii) Phosphonium compound