JPH02107615A - Production of isocyanurate group-containing polyisocyanate - Google Patents

Abstract

PURPOSE:To obtain the title polyisocyanate causing little discoloration by converting an aliphatic diisocynate into a polyamide polymer in the presence of a catalyst followed by depolymerization. CONSTITUTION:In the presence of a catalyst (pref. quaternary ammonium salt compound), an aliphatic diisocyanate( pref. 1,6-hexamethylene diisocynate) is heated at pref. 0-50 deg.C followed by heating at 60-100 deg.C to convert part or the whole of said diisocyanate into a polyamide-type polymer, which is then put to isocyanurate modification, thus obtaining the objective polyisocyanurate suitable as an curing agent for polyurethane resins.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for producing polyisocyanates containing aliphatic isocyanurate groups.

[Conventional technology]

Many studies have been conducted regarding methods for producing aliphatic isocyanurate group-containing polyinsyanate. Japanese Patent Publication No. 12888/1988 describes a method using potassium or sodium carboxylate as a catalyst;
No. 181078 describes a method using a quaternary ammonium salt compound as a catalyst, and JP-A-58-198517 describes a method using an aminosilyl compound as a catalyst.

[Problem that the invention seeks to solve]

Many aliphatic isocyanurates are used as polyurethane resins by reacting with polyols. One of the characteristics of the aliphatic isocyanurate used here is that it is non-yellowing.

Aliphatic isocyanurates are mainly used in fields such as coatings where their non-yellowing and b5% characteristics are utilized. Therefore, it goes without saying that the color of the aliphatic isocyanurate compound itself is preferably colorless. JP 63-12888 and JP 60-1810
The aliphatic isocyanurate produced according to Publication No. 78 has a pale yellow color, and there is a demand for an aliphatic isocyanurate with further reduced coloring. Furthermore, with the technology disclosed in JP-A-58-198517, products with a relatively low degree of coloration can be obtained in some cases, but it is still unsatisfactory and may require the use of large quantities of expensive catalysts. It has unavoidable drawbacks.

[Means for solving problems]

In view of the above-mentioned actual situation, the present inventors conducted extensive research to provide an aliphatic isocyanurate group-containing polyinsyanate with a very low degree of coloration, and as a result, completed the present invention.

That is, in the present invention, in producing an isocyanurate group-containing polyisocyanate by polymerizing an aliphatic diisocyanate in the presence of a catalyst, (a) a part or all of the aliphatic diisocyanate is made into an all-polyamide type polymer; (b) The method for producing an isocyanurate group-containing void isocyanate is characterized in that the polyamide type polymer is then depolymerized by heating.

Examples of the polymerization catalyst used in the present invention include basic catalysts that are already known isocyanurate catalysts for aliphatic diisocyanates, carboxylic acid salts of alkali metals such as sodium and potassium, pulcorates, and quaternary
Quaternary ammonium salt compounds including quaternary ammonium hydroxide, quaternary ammonium carboxylates, and derivatives thereof are used. Particularly preferred catalysts include quaternary ammonium salt compounds. The effect is particularly remarkable when this compound is used as a catalyst.

The amount of the isocyanurate catalyst used is 1 to 10,000 pp per total charge of incyanate compounds.
A range of m is appropriate.

The aliphatic diincyanate used in the present invention includes:
Examples include 1,4-tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate, and 2.4.4-1-limethylhexamethylene diisocyanate. Especially 1,
It is preferred to use 6-hexamethylene diincyanate.

In the reaction of the present invention, an organic solvent inert to incyanate may be used without a solvent. Specifically, all solvents generally usable in urethanization reactions can be used, such as acetic acid esters such as ethyl acetate, butyl acetate, and seron acetate, and aromatic hydrocarbons such as toluene and xylene. The reaction temperature in the present invention is 55°C or less, preferably 0 to 50°C. In this range, the polyamide type 1 coalescence production reaction and the isocyanurate formation reaction proceed simultaneously. When the desired reaction rate is reached, the reaction temperature is increased. The final temperature is preferably 60°C to 100°C. If the temperature is below 60°C, the incyanate compound that has become a polyamide type polymer cannot be depolymerized to isocyanurate, resulting in disadvantages such as poor compatibility between the final product and the organic solvent. . Moreover, if it is 100°C or higher, the coloring of the produced isocyanurate compound will increase, which is not preferable. Then, the reaction is stopped when the polyamide type 1 coalescence disappears. As a method for detecting the polyamide type 1 combination, Del Permulation chromatography (hereinafter referred to as GPO) can be used. The molecular weight of the polyamide type polymer produced in the present invention is 10
,000 or more, and the molecular weight of the produced isocyanurate is usually 3,000 or less. Therefore, G
After separating these using PC, the presence of the polyamide type polymer can be detected by detecting with a refractometer or the like.

In order to stop the reaction, a catalyst deactivator is usually used. Examples of the deactivating agent include various acids such as phosphoric acid, hydrochloric acid, sulfuric acid, monochloroacetic acid, and monofluoroacetic acid, and various organic halides such as benzoyl chloride.

From the reaction mixture in which the catalyst has been deactivated in this way, after removing the deactivated catalyst as the case may be, unreacted raw material diisocyanate is removed by a known method such as extraction or distillation, and the desired isocyanurate is obtained. Group-containing polyisocyanates can be obtained.

〔Effect of the invention〕

The method for producing aliphatic isocyanurate group-containing polyisocyanates according to the present invention uses a small amount of catalyst, and the resulting aliphatic incyanate group-containing polyisocyanates are mostly colorless. Another surprising feature is the high hexamer content of the monomer. This feature is 2
It can be inferred that this is due to the fact that two different reactions are carried out simultaneously and one product is finally obtained.

The aliphatic isocyanurate compound produced according to the method of the present invention having such features is industrially extremely important as a curing agent for polyurethane resins, and can be used as a base polyol for polyurethane resins, various polyester polyols including alkyd resins, In combination with polyurethane polyols such as polyether polyols or acrylic polyols, and substances that are reactive with incyanate groups such as hydroxyl groups, for example, epoxy resins, paints, adhesives, nidistomers RIM (in-mold reaction type), AC! M(
It can be put to practical use as various industrial materials such as composite materials including high performance composite materials).

〔Example〕

Next, the present invention will be specifically explained using examples.

Compatibility with organic solvents was determined by adding the final product to 100 parts by weight of a sample solution diluted with toluene to a solid content of 10% under stirring.
- Hexane was added, and the parts by weight (dilution index) of n-hexane required until turbidity occurred was measured.

The content of 3it bodies etc. was determined from the area percent occlusion of each t-ku obtained by GPO measurement using the following apparatus.

・Apparatus: Toyo Soda Co., Ltd. pLC-802A ・Column:
Toyo Soda Co., Ltd. G100OHXL x 1”
G2000HXL x 1" G3QQQHXL x 1 Φ Carrier 12 Tetrahydrofuran ・Detection method: Differential refractometer ・Theta processing: Toyo Ichitatsu Co., Ltd. 0P80 [10 Viscosity was measured using an Emirr type rotary viscometer.

Example 1 Hexamethylene diincyanate (hereinafter referred to as HD) 600 ml was added to a glass flask equipped with a thermometer, a stirrer, and a nitrogen-sealed tube under a nitrogen gas atmosphere.
．． ? ' and soaked in an oil bath. The temperature of the charged hexamethylene diisocyanate was raised to 50°C by stirring and raising the temperature of the oil bath while blowing nitrogen into the flask.

Then, as a catalyst, a 20% solution of tetramenal ammonium trifuriate in methyl seron rub acetate was added into the flask every 30 minutes in 6 equal portions. The total amount of catalyst solution added was 150 ppm based on the raw HDI. Three hours after the first addition of the catalyst solution, GPC measurements showed that the boryamida type 1 compound and the isocyanurate type polymer were
I confirmed that it was generated. (See Figure 1) Next,
The reaction temperature was raised to 60°C and maintained for 1 hour. GPC
As a result of measurement, the polyamide type 1 coalescence had disappeared.

(See Figure 2) To terminate the reaction, 10% of phosphoric acid
% methyl cellosolve acetate solution g to 0.14. ! ii
'Added to the reactor.

Thereafter, the reaction mixture is cooled to room temperature and subjected to molecular distillation to obtain the desired isocyanurate compound 12[),! I got i'. The isocyanurate compound thus obtained was pale yellow in color and had a HAZIICN number of 50 or less. The results are shown in Table-1.

Examples 2 to 6 Reactions were carried out in the same manner as in Example 1, using the HD process, solvent, and catalyst temperature as shown in Table 1. The results are shown in Table-1.

Comparative Examples 1 to 3 Under the same conditions as in Example 1, 500 ppm of catalyst solution was added and the reaction temperature was maintained at 60°C for 4 hours. As a result of measuring the reaction solution by GPO, no polyamide type polymer was produced. An isocyanurate compound was isolated in the same manner as in Example 1, and the HAZIICN number of the compound was 150. The results are shown in Table-2.
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[Brief explanation of the drawing]

FIG. 1 shows the GPO measurement results of the reaction solution after polymerization in Example 1 of the present invention, and FIG. 2 shows the GPC measurement results of the reaction solution after depolymerization in Example 1 of the invention. Patent applicant Asahi Kasei Korai Co., Ltd. Figure 1 Molecule I Figure 2 Molecular weight

Claims (1)

[Claims] In producing an isocyanurate group-containing polyisocyanate by polymerizing an aliphatic diisocyanate in the presence of a catalyst, (a) part or all of the aliphatic diisocyanate is converted into a polyamide type polymer, (b) then, A method for producing an isocyanurate group-containing polyisocyanate, which comprises depolymerizing the above polyamide type polymer by heating.