JPH1112342A - Production of isocyanurate ring-containing polyisocyanates - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing the subject compound, by which the reaction is completely stopped when the content of a NCO group reaches a desired value. SOLUTION: An acidic compound, especially acidic phosphoric acid ester as a catalyst-poisoning material is added to a reaction system to stop the reaction, when an isocyanuration reaction of a monomer polyisocyanate and/or a polyisicyanate partially urethanized with a mono- to tri-hydric alcohol in the presence of a catalyst comprising potassium fluoride, or the potassium fluoride in combination with one or more kinds compounds selected from a polyethylene oxide compound, a quarternary ammonium salt and a phosphonium compound.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a polyisocyanate having an isocyanurate ring, which is useful as a curing agent when producing a polyurethane resin such as a polyurethane paint or a casting material.

[0002]

BACKGROUND OF THE INVENTION Polyisocyanates having an isocyanurate ring in the molecule are:
Excellent weather resistance, heat resistance, chemical resistance, etc., paints, adhesives,
It is used as a raw material for urethane such as elastomers, artificial leathers and foams, and as a material for plastic lenses.

[0003] A number of patent applications have been filed for a method for producing an isocyanurate ring-containing polyisocyanate. Among them, Japanese Patent Publication No. 7-5573 and Japanese Patent Publication No.
No. 5574, potassium fluoride, or one or two compounds selected from the group consisting of (1) polyethylene oxide compounds, (2) quaternary ammonium salts, and (3) phosphonium compounds together with potassium fluoride. The method using the above combination as a catalyst gives an almost colorless and transparent isocyanurate ring-containing polyisocyanate. In particular, when 2,4-tolylene diisocyanate is used as a starting material, only the trimer is selectively used. It is known as an excellent production method.

However, as a monomeric polyisocyanate, 4,4'-diphenylmethane diisocyanate (MD
i), hexamethylene diisocyanate (HDi),
When a material having little difference in reactivity between two isocyanate groups such as 2,5- and / or 2,6-diisocyanatomethylbicyclo [2,2,1] heptane (NBDi) is used as a raw material, Since the polynuclear of the above monomer polyisocyanate is generated with the progress of the nullation reaction and the NCO group content decreases, it is necessary to stop the reaction halfway to obtain the desired NCO group content. There is.
JP-B-7-5573 and JP-B-7-5574 describe that there is no problem if the catalyst is removed by filtration at the end of the isocyanuration reaction or the catalyst is left as it is in the reaction product. However, it is not preferable to leave the catalyst in the system in order to stop the reaction halfway,
When the reaction is stopped by removing the catalyst by filtration, any NCO
It is difficult to obtain a group content, which is not preferable. Even if the catalyst is removed by filtration, it is difficult to completely stop the reaction because the catalyst for the solubility remains in the system, and the reaction may proceed due to heating when removing the reaction solvent and unreacted monomers. In addition, there is a problem that the obtained isocyanurate ring-containing polyisocyanate is not stable. Therefore, it has been desired to develop a method capable of completely stopping the reaction when the desired NCO group content is reached.

[0005]

Means for Solving the Problems In view of these points, the inventors of the present invention have conducted intensive studies and studies, and as a result, in an isocyanuration reaction using the above-mentioned catalyst, an acidic substance is added to the reaction system as a catalyst poisoning substance. As a result, they found that the reaction stopped instantaneously and completely, and completed the present invention.

That is, the present invention relates to potassium fluoride or one or more compounds selected from (1) polyethylene oxide compounds, (2) quaternary ammonium salts, and (3) phosphonium compounds together with potassium fluoride. In carrying out the isocyanuration reaction of the monomeric polyisocyanate and / or the polyisocyanate partially urethanized with a 1-3-functional alcohol in the presence of a catalyst using a combination of A method for producing an isocyanurate ring-containing polyisocyanate, characterized by adding an acidic substance as a substance into a reaction system to terminate the reaction. Further, the present invention is characterized in that in the above-mentioned method, the acidic substance is an acidic phosphate. Further, the present invention is characterized in that, in the above-mentioned method, the acidic substance is an acidic phosphate ester containing an alkoxy group or an alkylene oxide group.

[0007]

DETAILED DESCRIPTION OF THE INVENTION The catalyst used in the present invention is selected from potassium fluoride or (1) polyethylene oxide compound, (2) quaternary ammonium salt, and (3) phosphonium compound together with potassium fluoride. A catalyst using one or a combination of two or more compounds, and the potassium fluoride used may be in any of various forms such as pellets, powders, and flakes.
Spray-dried potassium fluoride (sd.KF) is particularly preferred because of its low hygroscopicity and high activity.

As examples of the compounds (1) to (3) used in combination with potassium fluoride, the polyethylene oxide compound (1) includes 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, [Cryptofix-
111], such as cryptands such as C ₁₄ H ₂₈ N ₂ O ₄ , and the quaternary ammonium salts of (2) include benzyltriethylammonium chloride,
Examples of the phosphonium compound (3) such as tetrabutylammonium bromide include trioctylethylphosphonium bromide and tetrabutylphosphonium chloride.

The amount of the catalyst used is usually from 10 to 1000 ppm, preferably from 10 to 1,000 ppm, based on the isocyanate compound.
00 ppm.

The monomer polyisocyanate used in the present invention may be either an aliphatic polyisocyanate or an aromatic polyisocyanate. Examples of aliphatic polyisocyanates are 2,5- and / or 2,6
Diisocyanatomethylbicyclo [2,2,1] heptane (NBDi), hexamethylene diisocyanate (H
Di), 1-isocyanato-3,3,5-trimethyl-
5-isocyanatomethylcyclohexane (IPDi),
Hydrogenated xylylene diisocyanate (hydrogenated XDi) and 2,4,4 or 2,2,4-trimethylhexamethylene diisocyanate (TMDi). Examples of aromatic polyisocyanates include 2,4'- or 4,4'-diphenylmethane diisocyanate (MDi), tolidine diisocyanate (TODi), xylylene diisocyanate (XDi), and naphthalene diisocyanate (N
Di) and the like.

[0011] The monomer polyisocyanate to be subjected to the isocyanuration reaction may be a mixture of at least two or more of the above-mentioned monomer polyisocyanates.

Further, these monomeric polyisocyanates and polyisocyanates partially urethanized with 1-3 functional alcohols are also suitably used as raw materials.
Examples of the 1-3 functional alcohol used here include, for example, methanol, ethanol, various butanols,
2-ethyl-hexanol, ethylene glycol, 1,
2- or 1,3-propylene glycol, neopentyl glycol, 2-ethyl-1,3-hexanediol, trimethylolpropane, glycerin, 1,2,6
-Low molecular weight compounds such as hexanetriol, and polyester polyols and polyether polyols having a molecular weight of about 200 to 10,000.

The NCO / OH equivalent ratio in the preliminary reaction between the alcohol and the monomeric diisocyanate is selected from values of about 10 to 100 depending on the purpose.

An acidic substance is used as a catalyst poisoning substance.
Examples of the acidic substance include hydrochloric acid, phosphoric acid, sulfuric acid, dichloroacetic acid, trichloroacetic acid, benzoyl chloride, acetyl chloride, benzenesulfonic acid and the like. However, these exemplified substances tend to generate suspended matters and add color to the product when the catalyst poisoning substance is added. Therefore, among the acidic substances, acidic phosphates capable of producing a polyisocyanate having a colorless and transparent isocyanurate ring without generating a floating substance are preferable.

The acidic phosphate in the method of the present invention is represented by the general formula (1)

Embedded image [Wherein R is the same or different and has an alkyl group having 1 to 20 carbon atoms, an aryl group, or an arylalkyl group;
It is an alkyl group having 1 to 20 carbon atoms containing an alkoxy group or an alkylene oxide group, and n is 1 or 2. ] It is a compound represented by these.

Of these, an acidic phosphate ester containing an alkoxy group or an alkylene oxide group is particularly preferred.

Examples of the acidic phosphate represented by the general formula (1) include diethyl phosphate, dibutyl phosphate, dioctyl phosphate, dilauryl phosphate, diphenyl phosphate, monoethyl phosphate, monobutyl phosphate, monooctyl phosphate, and monolauryl phosphate. And monophenyl phosphate.

Examples of the acidic phosphate ester (1) containing an alkoxy group include monomethoxymethyl phosphate, dimethoxymethyl phosphate, monoethoxymethyl phosphate, diethoxymethyl phosphate, monopropoxymethyl phosphate, dipropoxymethyl phosphate, and monobutoxymethyl. Phosphate, dibutoxymethyl phosphate, monobutoxyethyl phosphate, dibutoxyethyl phosphate and the like can be mentioned.

Examples of the alkylene oxide group-containing acidic phosphate (1) include mono [1- (1-butoxy-2).
-Propoxy) -2-propyl] phosphate, di [1
-(1-butoxy-2-propoxy) -2-propyl]
Phosphate, mono [tri (1,2-propylene glycol monobutyl ether)] phosphate, di [tri (1,2-propylene glycol monobutyl ether)] phosphate, mono [tetra (1,2-propylene glycol monobutyl ether)] phosphate, Di [tetra (1,2-propylene glycol monobutyl ether)] phosphate, mono [penta (1,2-propylene glycol monobutyl ether)] phosphate, dipenta [(1,2-propylene glycol monobutyl ether)] phosphate and the like. .

The amount of the catalyst poisoning substance used is preferably 0.5 to 10 equivalents, more preferably 0.8 to 5 equivalents per equivalent of the catalyst.

The isocyanuration reaction is usually carried out at 0 to 12
It is carried out at a temperature of 0 ° C, preferably 20-70 ° C.

The progress of the reaction can be carried out by isocyanato titration of the reaction solution by the di-n-butylamine method, gas chromatography, refractive index, viscosity, infrared spectrometry and the like. When the reaction reaches the desired conversion, the catalyst is deactivated by the addition of a catalyst poison to stop the reaction. In the reaction, the conversion of the monomer polyisocyanate is from 5 to 85%,
It is preferably carried out until it reaches 10 to 60%. A solvent may be used in the reaction. Suitable solvents are, for example, fatty acid esters such as ethyl acetate, butyl acetate and methoxypropyl acetate, and aromatic hydrocarbons such as toluene and xylene. After completion of the reaction, if unreacted monomeric polyisocyanate and a solvent are used from the reaction solution, the solvent is removed and purification is performed. Examples of the purification method include distillation under reduced pressure and solvent extraction. In general, a falling-type thin film evaporator is suitably used. For safety to the human body, the content of monomeric polyisocyanate in the product polyisocyanate must be 1.0% by weight or less.

[0023]

The present invention will be specifically described below with reference to examples.
The method of the present invention is not limited by the examples. Example 1 1000 g of NBDi was charged into a four-necked flask equipped with a reflux condenser, a thermometer, and a stirrer, and heated to 70 ° C. while stirring the inside of the reactor under a nitrogen stream, and potassium fluoride was mixed in advance. 0.1 g and 10 g of polyethylene glycol (PEG400) having an average molecular weight of 400 were added dropwise over 30 minutes. The temperature inside the reactor is gently 75 ℃
After maintaining the temperature for a while, gradually increase the temperature to 70 ° C.
Down to Four hours after the start of the exotherm, 0.2 g of dibutyl phosphate was added as a terminator, and then 70 ° C.
For about 1 hour. Gas chromatography analysis showed that the monomer conversion was 40%, and the monomer conversion after stirring for 2 hours was 40%. This confirmed that the reaction was completely stopped. The reaction mass was colorless and transparent. Then, unreacted monomers were removed by a thin film evaporator. The obtained product was a colorless and transparent solid having an APHA of 30 or less at room temperature, and had a melting point of 50 to 60 ° C, an NCO content of 17.4%, and a monomer content of 0.5%. The product yield was 400 g, 40% conversion from NBDi.

Example 2 The procedure of Example 1 was repeated, except that 0.3 g of dibutoxyethyl phosphate was used instead of dibutyl phosphate. After the addition of the acidic substance, the reaction was completely stopped. The reaction mass was colorless and transparent, and the product obtained after removing the unreacted monomer was a colorless and transparent solid.

Example 3 The procedure of Example 1 was repeated except that 0.2 g of monobutoxyethyl phosphate was used instead of dibutyl phosphate, and 1000 g of HDi was used instead of NBDi. After the addition of the acidic substance, the reaction was completely stopped. The reaction mass was colorless and transparent, and the product obtained after removing the unreacted monomer was a colorless and transparent solid.

Example 4 0.4 g of mono [1- (1-butoxy-2-propoxy) -2-propyl] phosphate was used instead of dibutyl phosphate, and 1000 g of MDi was used instead of NBDi.
Except using, it carried out similarly to Example 1. After the addition of the acidic substance, the reaction was completely stopped. The reaction mass was colorless and transparent, and the product obtained after removing the unreacted monomer was a colorless and transparent solid.

Example 5 0.6 g of di [tri (1,2-propylene glycol monobutyl ether)] phosphate was used in place of dibutyl phosphate, and HDi was 1000 in place of NBDi.
Except using g, it carried out similarly to Example 1. After the addition of the acidic substance, the reaction was completely stopped. The reaction mass was colorless and transparent, and the product obtained after removing the unreacted monomer was a colorless and transparent solid.

Example 6 The procedure of Example 1 was repeated, except that 0.2 g of phosphoric acid was used instead of dibutyl phosphate. Shortly after the phosphoric acid was added, a white suspension was generated, and the reaction was completely stopped. The resulting product after removal of unreacted monomer was a white solid.

Example 7 The procedure of Example 1 was repeated, except that 0.3 g of benzoyl chloride was used instead of dibutyl phosphate. After the addition of the acidic substance, the reaction was completely stopped. The product obtained after removal of the reaction mass and unreacted monomer had a color.

Example 8 1000 g of NBDi was charged into a four-necked flask equipped with a reflux condenser, a thermometer and a stirrer, and heated to 70 ° C. while stirring the inside of the reactor under a nitrogen stream, and mixed in advance. 0.1 g of potassium fluoride and 10 g of polyethylene glycol (PEG400) having an average molecular weight of 400 were added dropwise over 30 minutes. The temperature inside the reactor is gently 75 ℃
After maintaining the temperature for a while, gradually increase the temperature to 70 ° C.
Down to Four hours after the start of the exotherm, 0.2 g of dibutyl phosphate was added as a terminator, and then 70 ° C.
For about 1 hour. As a result of analysis by the di-n-butylamine method, the NCO group content was 37.5%. After storage at room temperature under a nitrogen atmosphere for one week, there was no change in the NCO group content.

Comparative Example 1 A four-necked flask equipped with a reflux condenser, a thermometer, and a stirrer was charged with 1000 g of NBDi, heated to 70 ° C. while stirring the reactor under a nitrogen stream, and mixed in advance. 0.1 g of potassium fluoride and 10 g of polyethylene glycol (PEG400) having an average molecular weight of 400 were added dropwise over 30 minutes. The temperature inside the reactor is gently 75 ℃
After maintaining the temperature for a while, gradually increase the temperature to 70 ° C.
Down to Stirring became impossible 7 hours after the start of heat generation, and 8
Over time it solidified to white. Dissolve the product in butyl acetate,
As a result of analysis by the di-n-butylamine method, the NCO group content was 2.1%.

Comparative Example 2 1000 g of HDi was charged into a four-necked flask equipped with a reflux condenser, a thermometer, and a stirrer, and the temperature was raised to 70 ° C. while stirring the inside of the reactor under a nitrogen stream. 0.1 g of potassium fluoride and 10 g of polyethylene glycol (PEG400) having an average molecular weight of 400 were added dropwise over 30 minutes. The temperature inside the reactor was gradually increased to 75 ° C., maintained at that temperature for a while, and gradually decreased to 70 ° C. Four hours after the start of heat generation, unreacted monomers were removed by a thin-film evaporator, but solidified in the thin-film evaporator in white. The product was dissolved in butyl acetate and analyzed by the di-n-butylamine method. As a result, the NCO group content was 3.5%.

Comparative Example 3 A four-necked flask equipped with a reflux condenser, a thermometer and a stirrer was charged with 1000 g of NBDi, heated to 70 ° C. while stirring the inside of the reactor under a nitrogen stream, and mixed in advance. 0.1 g of potassium fluoride and 10 g of polyethylene glycol (PEG400) having an average molecular weight of 400 were added dropwise over 30 minutes. The temperature inside the reactor is gently 75 ℃
After maintaining the temperature for a while, gradually increase the temperature to 70 ° C.
Down to Four hours after the start of the heat generation, potassium fluoride was removed by filtration, and the content was analyzed by the di-n-butylamine method. As a result, the NCO group content was 37.5%. After one week storage at room temperature under a nitrogen atmosphere, the NCO group content was 36.7%.

[0034]

According to the present invention, a polyisocyanate having an isocyanurate ring having a desired NCO content can be produced by using an acidic substance as a catalyst poisoning substance.
Further, by using the acidic phosphoric acid ester (1) as a catalyst poisoning substance, a colorless and transparent polyisocyanate having an isocyanurate ring can be produced without generating suspended matters.

 ──────────────────────────────────────────────────続 き Continued from the front page (72) Inventor Joji Morisaki 30 Asamuta-cho, Omuta-shi, Fukuoka Prefecture Mitsui Toatsu Chemicals Co., Ltd.

Claims (3)

[Claims] (1) potassium fluoride, or (1) a polyethylene oxide compound together with potassium fluoride, (2)
In the presence of a catalyst using one or a combination of two or more compounds selected from quaternary ammonium salts and (3) phosphonium compounds, monomeric polyisocyanates and / or 1-3-functional alcohols are used. An isocyanurate ring-containing polyisocyanate characterized by adding an acidic substance as a catalyst poisoning substance to a reaction system and terminating the reaction in performing an isocyanuration reaction of a partially urethanized polyisocyanate. Nart manufacturing method. 2. The method according to claim 1, wherein the acidic substance is an acidic phosphate. 3. The method according to claim 1, wherein the acidic substance is an acidic phosphate ester containing an alkoxy group or an alkylene oxide group.