JPS61151179A - Production of hexamethylene isocyanurate compound - Google Patents

Abstract

PURPOSE:In producing the titled compound useful as a coating compound, etc. by trimerizing hexamethylene diisocyanate in the presence of a catalyst, to obtain the aimed compound having improved qualities advantageously, by adding a specific amount of 6-9C aliphatic monool to the reaction system. CONSTITUTION:In producing the titled compound by trimerizing hexamethylene diisocyanate (HDI) in the presence of a well-known catalyst such as a tertiary amine, etc., 0.5-5.0wt% based on 100pts.wt. HDI of 6-9C aliphatic monool such as 2-ethylhexanol, etc., is added to the reaction system, NCO group is partially urethanized simultaneously with the trimerization of isocyanurate, this urethane group shows a cocatalytic effect while keeping uniform reaction, and reduces an amount of the catalyst required to obtain the same isocyanurate polymerization ratio. Consequently, turbidity and coloring of product are improved, and a formed film of coating having improved heat resistance, light resistance, etc., is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to hexamethylene diisocyanate (hereinafter referred to as HpI
11L Dan! - Urethane compositions made from MDI as a raw material have excellent light resistance and are used for applications such as paints due to their non-yellowing properties; on the other hand, urethane compositions made from aromatic diisocyanates as raw materials It has poor heat resistance compared to DI, and there is also a problem with the toxicity of DI itself.

Therefore, these shortcomings of MDI can be improved and no-HDI (
A production method is known in which MDI or its urethane-modified prepolymer is trimerized in the presence of a catalyst in order to contain or have an isocyanurate ring in the middle of the urethane-modified prepolymer thereof.

Generally, various catalysts are used to trimerize organic isocyanates, that is, to convert them into isocyanurates. Showa 5
2-69497), fatty acid sodium or potassium salt (Japanese Patent Application Laid-Open No. 57-47319), tertiary alkyl phosphine (Japanese Patent Application Laid-open No. 58-162623), and the like are known.

However, these known catalysts are rarely effective against aliphatic isocyanates, and the isocyanate group of MDI hardly progresses, or a large amount of catalyst must be used, and therefore the reaction solution is Undesirable phenomena such as coloring and the formation of insoluble substances occur. In addition, a duplex reaction and a polycyclic compound with a high degree of polymerization occur in parallel with trimerization, and the dimerized product is unstable and easily dissociated, and polycyclic compounds cause turbidity or insoluble matter in the product. When an isocyanurated HDI reaction product containing isocyanurate is used in a paint or the like, the excellent performance of the isocyanate group is degraded and the commercial value of the paint is reduced.

As an improvement method for these, MDI polyol attached 210
Methods have also been proposed for carrying out isocyanate polymerization of bodies. (Japanese Patent Application Laid-Open No. 57-47321, these methods are
The method is characterized in that a polyol adduct of IDI is produced using a partner polyol with a molecular weight of 3000 or less and a functionality of 2 to 3, and then a trimerization catalyst is used.However, HDI is first reacted with a polyol. It is essential to carry out a step to reduce the amount of adhesion to zero, and the urethane reaction using polyol also generates heat, which requires careful management. If this step is omitted and the reaction is carried out by directly adding the polyol and trimerization catalyst to HDI, an exothermic and heterogeneous reaction will occur, and an insoluble substance will be produced, which will hinder the smooth progress of the reaction.

This is because a hydrogen bond is formed between the active hydrogen during urethane group formation and the oxygen atom in the isocyanate group, increasing the activity of the isocyanate group. It is presumed that this is because the reaction becomes more rapid in this case and a heterogeneous reaction cannot be avoided.

Problems to be Solved by the Invention The present inventors have made extensive studies to improve these drawbacks, and have discovered that it is possible to carry out a simple and mild reaction, and to obtain isocyanate compounds of MDI of good quality. Ta.

That is, in the method of the present invention, it is possible to add a monol compound and a trimerization catalyst to MDI all at once and cause the reaction to occur.
In this case, the reaction proceeds with a smaller amount of catalyst than that used when directly trimerizing MDI, and the disadvantages such as coloring and clouding of the reaction solution due to an increase in the amount of catalyst are alleviated, and the reaction is mild, so 1. It was found that the process proceeded smoothly without abnormal heat generation or runaway reactions, and that temperature control was extremely easy and products with a constant and controlled quality could be obtained.

Means for Solving the Problem The isocyanation reaction of MDI in the method of the present invention is as follows:
0.5 to 5 parts by weight of a monool having 6 to 9 carbon atoms per 1100 parts by weight of MD was added to MDI in the presence of a trimerization catalyst to partially urethanize the NCO groups of MDI.
Trimerization to isocyanurate is performed in the temple.

In the present invention, the catalysts include tertiary amines, alkyl-substituted ethyleneimines, acetylacetone metal salts,
Known catalysts such as coordination compounds of group (1) and (2) metals and metal salts of various organic acids may be used alone or in combination, and if necessary, a co-catalyst may be used.

Cyclohexanol is a monool.

2-ethylhexanol, trimethylhexanol, octyl alcohol, etc. can be used. These C
Aliphatic alcohols other than &~Q are undesirable because they produce insoluble components and cause the product to become cloudy.

In addition, it is desirable that the urethane group concentration due to monool addition be about 5 or less of the total isocyanate groups in HDI, and for that purpose, the added charge monool should be 0.5 to 5.0 parts by weight per 1100 parts by weight of MD. Must be used within the range. because.

Almost all of the monol is consumed in the urethanization reaction, so if 5.0 parts by weight or more of the monol is added, the urethane group concentration will be about 5% or more of the total isocyanate groups, and the urethane group concentration in the product will increase. This is because an increase in isocyanurate promotes the trimerization reaction to isocyanurate. However, in the present invention, it is sufficient that the urethane group is present in the reaction system in a trace amount of about 0.3 parts by weight or more relative to the isocyanate group, but if the amount of monool added is 0.5 parts by weight, it is sufficient. In the following, the effect cannot be exhibited due to insufficient urethane group content in the reaction system.

In the present invention, by adding a specific monool in this way, a urethane compound is produced and contained in the isocyanurate reaction system, and this urethane group exhibits a promoter effect while maintaining a uniform reaction. As a result, it is possible to reduce the amount of catalyst necessary to obtain the same isocyanate polymerization rate, and defects such as coloring and clouding of the product are improved.

JP-A-58-162581 has a description that the alcoholic hydroxy compound used for urethanization of t(DI) may also be used as a co-catalyst, and the amount added is 0.01 to HDI. It is clearly stated that it is sufficient to use ~0.2 t, and that using more than this has the disadvantage of causing side reactions and producing highly viscous products, but regardless of the type of catalyst, at least 0 for HDI. It is surprising that even if a specific monool is used in a large amount of .5 weight or more, a uniform reaction can be maintained without causing gelation during the reaction.

In the method of the present invention, the amount of catalyst varies depending on the activity of the catalyst used, and the amount of catalyst can be reduced by using a co-catalyst, but the amount of catalyst is at most 0.2 with respect to HDI.
%, and depending on the type of catalyst it is preferable to use a known co-catalyst such as phenol or cresol, but it is sufficient that the amount is equal to or less than the amount of the catalyst.

In the present invention, the reaction temperature is usually 100°C or lower, preferably 40 to 80°C. If the temperature is 100''C or higher, polymers of isocyanate compounds are likely to be formed, which may cause gelation or coloring.

The reaction time varies depending on the type and amount of catalyst and the reaction temperature, but 3 to 10 hours is usually sufficient.

The decrease in N G O as the isocyanate group progresses can be measured by titration analysis, so it is sufficient to stop the reaction when the predetermined NCO content is reached. The NGO content, viscosity, etc. of the reactant can be changed freely.

Examples of the terminator include commonly used acidic compounds such as hydrochloric acid and phosphoric acid.

The obtained reaction product is subjected to known methods such as extraction and distillation to remove unreacted HDI as much as possible to obtain an isocyanate compound.

Generally, the MDI content in the product, either as a pure substance or in solution when the product is used as a solution in an organic solvent, is 3.
From the viewpoint of toxicity, it is preferable that the content be 0% by weight or less, preferably 1.0% by weight or less, and if a large amount of polycyclic products (more than dimers) is present in the product, physical properties such as viscosity and hardness may be affected. In addition to this problem, the compatibility with the solvent decreases and cloudiness occurs, so it is known that the polymerization rate is usually suppressed to 60% or less. However, in the present invention, N
It is preferable to adjust the reaction using the above terminator so that the amount of CO group-containing groups is approximately 0% by weight.

Furthermore, since the dimer in the product clearly appears with a molecular weight of around 504 by liquid chromatography, it can be quantified, and an infrared absorption spectrum shows a clear absorption at 1680 cm.

The polycyclic compound content can also be determined by a similar method. In addition, the formation of the dimer is indicated by 1 in the infrared absorption spectrum.
7 It can be confirmed by s carving 3 absorption.

Products containing isocyanate groups obtained by the method of the present invention not only have improved turbidity and coloration, but also free H
Although the DI is 1- or less, there are very few polymer compounds due to side reactions, so it has a lower viscosity than conventional MDI polymers, and has a higher NCO content. When urethanization and trimerization are carried out using
Regarding the ratio of isocyanate groups to urethane groups, the ratio of isocyanate rings is higher when using monools than when using diols, so when used as a coating composition etc. There are advantages such as being able to invite aI humiliated list.

In the NMR spectrum of the product, methylene protons of MDI)-limer appear at 3.9 ppm and methylene protons of urethane appear at 4.1 ppm, so the molar ratio of trimer and urethane can be determined from the integral ratio of each signal.

The present invention will be further explained below with reference to Examples, but the present invention is not limited thereto, and parts and parts refer to parts by weight and % by weight.゛Example 1 500rnl with thermometer, stirrer and nitrogen sealed tube
4Pour 200 parts of HDI into a glass flask and add 2-
A mixture of 8.01 i ethylhexanol, 0.2 part sodium caprate and 0.1 part phenol is added. The reaction was carried out at about 80° C. for 5 hours while stirring under a nitrogen stream. The NGO content of the reaction solution was 42.0%. 0.14 part of phosphoric acid was added, and the mixture was further stirred at this reaction temperature for about 1 hour. The product is a transparent liquid with a slight yellowish tinge, and is obtained by thin film distillation. MDI was distilled off.

The resulting liquid was pale yellow and transparent, and its NGO content, viscosity, and free HDI were as shown in the table.

In the infrared absorption spectrum of this liquid, a strong absorption characteristic of isocyanate groups was observed at 1680-'am, and no absorption at 1780-1cIR, characteristic of the dimer, was observed.

In addition, 200 parts of HDI and 2-
8 parts of dicarboxylic hexanol was added and reacted at 70°C for 2 hours. No unreacted 2-ethylhexanol was found in the reaction solution, and the NCO group content of the reaction solution was 46.8%. This is approximately 2.7 of the isocyanate groups in the raw material MDI.
% was consumed in urethanization with ethylhexanol.

Example 2 Using the apparatus of Example 1, 3.4 parts of 2-ethylhexanol and 0.2 parts of triethylamine were added to 200 parts of MDI, and the mixture was reacted at 80°C for 7 hours. Reaction solution 0lOO content is 4
It's 3.5 inches.

The reaction was stopped using 0.05 parts of phosphoric acid and treated in the same manner as in Example 1 to obtain a pale yellow transparent product.

These are shown in the table.

Example 3 Same <i(, 1 2-ethylhexanol in 200 parts DI
．． 5 parts and 0.1 part of acetylacetone lithium salt were added and reacted at 70°C for 3 hours. The N GO content of the reaction solution was 42.4.

The reaction was stopped by adding 0.01 part of phosphorus and stirring.

Thereafter, treatment was carried out in the same manner as in Example 1 to obtain a pale yellow and transparent product. These are shown in the table.

Example 4 1 (Processing was carried out in the same manner as in Example 3 except that 10.0 parts of cyclohexanol was used in 200 parts of DI. The NGO content of the reaction solution was 41.8% at 70° C. for 5 hours.

These are shown in the table.

Example 5 1.5 parts of octyl alcohol, 0.08 parts of acetal acetone zirconium salt and 0.04 parts of phenol were added to 200 parts of HDI, and the mixture was reacted at 80° C. for 5 hours under a nitrogen stream. The N GO content of the pale yellow and transparent reaction solution was 43.9%.
It's true. The reaction was stopped using 0.016 part of phosphoric acid and treated in the same manner as in Example 1 to obtain a pale yellow transparent product. These are shown in the table.

Example 6 Same as Example 1 <1.0 part of 2-ethylhexanol, 0.03 part of zirconium butoxide on a scale of 200 parts of HDI
NCO content of the reaction solution reacted with 0.01 part of phenol and 0.01 part of phenol at 80°C for 6 hours.

0.008 part of phosphoric acid was added as a terminator, and the mixture was stirred at the same consistency for 1 hour, filtered, and unreacted MDI was removed by thin film distillation. The product was a clear liquid with a slight yellow tinge, and its NCO content was 22.0 inches. These are shown in the table.

Comparative Example 1 Under the conditions of Example 1, without using 2-ethylhexanol, 0.2 parts of sodium caprate and 0.1 part of phenol as a cocatalyst were mixed with 200 parts of DI and heated to 80°C for 50 minutes under a nitrogen stream. The NGO content of the reaction solution reacted for a time is i9
．． a%, no absorption peculiar to the isocyanate ring was observed in the infrared absorption spectrum, indicating that the isocyanate group had not evolved at all.

Comparative Example 2 Under the conditions of Comparative Example 1, the catalyst sodium caprate was added to 0.5
The amount was increased to During the reaction, the temperature rapidly increased around 70°C, and the reaction solution changed from a deep brown color to a high viscosity and rapidly solidified, making it impossible to maintain the reaction.

Comparative Example 3 The reaction was carried out in the same manner as in Example 3 except that 2-ethylhexanol was removed. After reacting at 70°C for 3 hours, the NCO content was 47. Even if the reaction was continued for an additional 3 hours, the NGO content remained at 47.3%, and in this infrared absorption spectrum, almost no absorption of isocyanurate rings was observed.

Comparative Example 4 A reaction was carried out in the same manner as in Example 6, except that 2-ethylhexanol was omitted.

The reaction solution was almost colorless and transparent and contained 47.4% NGO water, but no absorption of isocyanurate rings was observed in the infrared absorption spectrum.

Comparative Example 5 Under the conditions of Comparative Example 4, the catalyst zirconium butoxide was
．． The reaction was carried out in the same manner at 80° C. except that the amount was increased to 0.06 parts. The NGO content of the reaction solution reached 45.8% after 6 hours of reaction, but the first reaction solution had a very strong yellowish tinge, and after removing unreacted ■DI, it was strongly colored to a brownish yellow and red. In the external absorption spectrum, the absorption of the isocyanurate ring was only slightly observed, and it was clear that it was not suitable for practical use.

The results are shown in the table together with Examples.

Claims (1)

[Claims] 1. When producing a hexamethylene isocyanurate compound by the trimerization reaction of hexamethylene diisocyanate in the presence of a catalyst, an aliphatic monool having 6 to 9 carbon atoms is added to 100 parts by weight of hexamethylene diisocyanate. A method for producing a hexamethylene isocyanurate compound, characterized in that 0.5 to 5.0 parts by weight of hexamethylene isocyanurate compound is present in the reaction system.