JP2000178333A - Production of polyisocyanate containing isocyanurate ring - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method capable of isocyanurating at a repeatable constant reaction rate. SOLUTION: In this method for producing a polyisocyanate contg. isocyanurate group, isocyanuration is carried out using potassium fluoride and a combination of one or more than two compds. selected from a polyethylene oxide compd. (1), a quaternary ammonium salt (2) and a phosphonium compd. (3), with an isocyanate contg. not more than 20 ppm carbon dioxide as catalysts and a dialkyl stannous compd. as an auxiliary catalyst.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a method for producing an isocyanurate ring-containing polyisocyanate useful as a curing agent for producing a polyurethane resin such as a polyurethane paint or a casting material.

[0002]

2. Description of the Related Art Isocyanurate ring-containing polyisocyanates obtained by converting isocyanates into isocyanurates are used in various applications such as foams, elastomers, paints and adhesives. A number of patents have been filed for the production of polyisocyanates containing isocyanurate rings. The present inventors have previously filed Japanese Patent Application No. Hei 9-15526.
In JP-A-7, potassium hydroxide is used as a catalyst together with one or more selected from (1) polyethylene oxide compounds, (2) quaternary ammonium salts, and (3) phosphonium compounds. A method for isocyanuration using a dialkyltin compound as a catalyst has been found and disclosed. This method is an excellent production method characterized by the fact that the reaction proceeds even at a low isocyanuration reaction temperature, the amount of catalyst used is small, and the obtained isocyanurate ring-containing polyisocyanate has a good hue. .

[0003]

However, when the isocyanate conversion reaction is carried out using the catalyst described in Japanese Patent Application No. 9-155267, even if the reaction is carried out under the same conditions, the catalyst activity of each batch is reduced. There has been a problem that there is variation and reproducibility cannot be obtained. If the catalyst activity differs from batch to batch, the reaction time differs from batch to batch, which is disadvantageous when industrialized. In addition, when the catalyst and / or the cocatalyst are added at a constant rate, if the catalytic activity is different, the amount of the catalyst used will be different for each batch. If the amount of the catalyst used is different for each batch, the amount of the catalyst contained in the isocyanurate ring-containing polyisocyanate of the product is not constant, and for example, when used as a paint, the coating film performance varies between products, which is not preferable. .

[0004] The problem to be solved by the present invention is to produce an isocyanurate ring-containing polyisocyanate by converting isocyanate into isocyanurate (1) a polyethylene oxide compound together with potassium fluoride as a catalyst, and (2) a fourth oxide. And (3) a method using one or more selected from phosphonium compounds, and further using a dialkyltin compound as a co-catalyst. The aim is to find a stable manufacturing method that can be converted.

[0005]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies in view of these points, and as a result, (1) a polyethylene oxide compound together with potassium fluoride as a catalyst;
When one or a combination of two or more selected from (2) quaternary ammonium salts and (3) phosphonium compounds is used, and a dialkyltin compound is used as a co-catalyst, the dissolved carbon dioxide in the isocyanate is reduced. The present invention was found to suppress the activity of the catalyst and, more surprisingly, found that the concentration of dissolved carbon dioxide was such an amount that it was not usually recognized as an impurity.

That is, the present invention relates to one or more selected from (1) polyethylene oxide compounds, (2) quaternary ammonium salts, and (3) phosphonium compounds together with potassium fluoride using isocyanate of 20 ppm or less of carbon dioxide as a catalyst. A method for producing an isocyanurate group-containing polyisocyanate, wherein isocyanuration is performed using a combination of two or more kinds and further using a dialkyltin compound as a promoter, isocyanate containing 8 ppm by weight or less of carbon dioxide. Using one or a combination of two or more selected from (1) polyethylene oxide compounds, (2) quaternary ammonium salts, and (3) phosphonium compounds together with potassium fluoride as a catalyst, and dialkyl as a co-catalyst Isocyanurate using tin compounds A method for producing an isocyanurate group-containing polyisocyanate, wherein the dialkyltin compound is a dialkyltin dicarboxylate, a dialkyltin dialkoxide, a dialkyltin dithioalkoxide, a dialkyltin oxide, Wherein the dialkyltin compound is a compound selected from the group consisting of dialkyltin sulfides; and the dialkyltin compound is dialkyltin dicarboxylates; and the dialkyltin compound is di-n-butyltindilaurate. The production method according to the above, wherein the isocyanate is 2,5 (6) -diisocyanatomethylbicyclo [2,2,1] heptane.

[0007]

DETAILED DESCRIPTION OF THE INVENTION In the present invention, it is important that the isocyanate used does not substantially dissolve carbon dioxide. Therefore, the isocyanate used in the present invention dissolves carbon dioxide of 20 ppm by weight or less, preferably 8 ppm by weight or less.

The isocyanurate industrial raw material isocyanates used hitherto contain about 20 to 100 ppm by weight of carbon dioxide immediately after the final distillation step. When carbon dioxide is used to produce isocyanate, for example, when a production method of phosgenating an amine carbonate is used,
You can get into that process. Also, carbon dioxide can enter by the intrusion of air. Carbon dioxide can be dissolved in the isocyanate by a decarboxylation reaction caused by urea generation due to intrusion of water during production or packing. Furthermore, if it is sealed once, it can be stored in a nitrogen-purged sample can.
It is known that up to 6000 ppm of carbon dioxide can be dissolved after months.

Accordingly, these isocyanates are:
It is necessary to remove dissolved carbon dioxide before the reaction. Examples of the removal method include a method in which an inert gas such as a nitrogen gas and an argon gas is blown vigorously into the isocyanate, and a method in which the inert gas is blown vigorously after reducing the pressure to 2 KPa, preferably about 0.5 KPa. Even if the dissolved carbon dioxide in the isocyanate is treated by the above method, about 20 to 40 ppm can easily remain. Therefore, it is necessary to measure the amount of the dissolved carbon dioxide and repeat the treatment until the concentration becomes 20 ppm by weight or less. preferable.

In addition, carbon dioxide may enter from outside air at the time of analysis sampling during the reaction, or may enter as dissolved carbon dioxide in the substance when a catalyst or other substances are added. Therefore, preferably, during the reaction, an inert gas such as a nitrogen gas or an argon gas is vigorously passed through the reactor, or an inert gas is passed through the reaction solution. When adding a catalyst or other substances, it is preferable to remove dissolved carbon dioxide in advance before adding.

In the present invention, the dissolved carbon dioxide in the isocyanate is measured by gas chromatography. Specifically, Waters Corpora is used for column packing.
Tion's Porapack Type S GC
Bulk Packing Material (Mesh
80-100) using the absolute calibration curve method.

The isocyanate used in the present invention may be an aliphatic isocyanate or an aromatic isocyanate. Examples of the aliphatic isocyanate include butyl isocyanate (BI), 2,5 (6) -diisocyanatomethylbicyclo [2,2,1] heptane (NBD
I), hexamethylene diisocyanate (HDI), 1
-Isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane (IPDI), xylylene diisocyanate (XDI), hydrogenated xylylene diisocyanate (hydrogenated XDI), 2,2,4-trimethylhexamethylene Examples of diisocyanate (TMDI) and aromatic isocyanate include phenyl isocyanate, tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), and naphthalene diisocyanate (NDI). It is not limited to these. These may be used alone or as a mixture of two or more.

A polyisocyanate partially urethanized with a 1-3 functional alcohol is also suitably used as a raw material. Examples of the 1-3 functional alcohol used herein include, for example, methanol, ethanol,
Various butanols, 2-ethylhexanol, ethylene glycol, 1,2- or 1,3-propylene glycol, 1,3- or 1,4- or 2,3-butylene glycol, 1,6-hexanediol, neopentyl glycol , 2-ethyl-1,3-hexanediol, trimethylolpropane, glycerin, low molecular weight compounds such as 1,2,6-hexanetriol and the like.
0 to 10,000 polyester polyols and polyether polyols.

The NCO / OH equivalent ratio in the preliminary reaction between the alcohol and the isocyanate is selected from values of about 10 to 1000 depending on the purpose. When the NCO / OH equivalent ratio is smaller than 10, valuable active isocyanate groups are reduced, which is not preferable.

The potassium fluoride used in the present invention may be in various forms such as pellets, powders, flakes and the like. However, because of its low hygroscopicity and high activity, spray-dried potassium fluoride (sd. KF) is particularly preferred.

Used together with potassium fluoride (1)
Examples of the polyethylene oxide compound include polyethylene glycols such as polyethylene glycol, polyethylene glycol monomethyl ether and polyethylene glycol dimethyl ether, and dibenzo-18-crown-
6, crown ethers such as dicyclohexyl-18-crown-6, for example, C ₁₄ H ₂₈ N ₂ commercially available as [Cryptofix-111] manufactured by Kanto Chemical Co.
And cryptands such as O ₄ .

Used together with potassium fluoride (2)
Examples of the quaternary ammonium salt include benzyltrimethylammonium chloride, tetrabutylammonium bromide and the like.

Used with potassium fluoride (3)
Examples of the phosphonium compound include trioctylphosphonium bromide, tetrabutylphosphonium chloride and the like.

The amount of potassium fluoride used is 0.000001 parts by weight based on 1 part by weight of the isocyanate and / or the partially urethanized polyisocyanate used in the reaction.
0.0005 parts by weight is sufficient, and preferably 0.000005 to 0.0002 parts by weight. (1)
The amount of the compound of (1) to (3) is 1/10 of potassium fluoride.
The amount is preferably 0 to 100 times.

In the method of the present invention, by using a catalyst comprising potassium fluoride and the above-mentioned compounds (1) to (3) in combination with a dialkyltin compound cocatalyst, the catalyst becomes more highly active, It can react at a small amount of catalyst and at a low temperature.

Specific examples of the dialkyltin compound used as a cocatalyst in the present invention include dialkyltin dicarboxylates such as dimethyltin diacetate, dibutyltin dioctanoate, dibutyltin dilaurate, dibutyltin dibutoxide, and dioctyl. Dialkyltin dialkoxides such as tin dibutoxide, dialkyltin dithioalkoxides such as dibutyltin di (thiobutoxide), dialkyltin oxides such as di (2-ethylhexyl) tin oxide, dioctyltin oxide and bis (butoxydibutyltin) oxide And dialkyltin sulfides such as dibutyltin sulfide. Of these, dialkyltin dicarboxylates are preferred, and di-n-butyltin dilaurate is more preferred.

In the present invention, dialkyltin halides such as dibutyltin dichloride and dimethyltin dichloride have almost no effect as a promoter.

The amount of cocatalyst used is preferably 1/10 to 10 times the amount of potassium fluoride used, and
In the following, the effect of the co-catalyst is small, and if the amount is more than 10 times, the product isocyanurate ring-containing polyisocyanate may have an adverse effect on physical properties such as cloudiness, which is not preferable.

In the present invention, there is no problem even if active hydrogen compounds such as alcohols and phenols and compounds generally known as co-catalysts for isocyanuration such as tertiary amines and phosphite triesters are used in combination. .

The catalyst and the cocatalyst may be added to the raw material isocyanate and / or the partially urethanized polyisocyanate, respectively, or may be added in advance by mixing.

In the present invention, in order to obtain an industrially advantageous reproducible isocyanurate reaction rate, it is necessary to remove the carbon dioxide in the isocyanurate, use the same isocyanate, use a catalyst and a catalyst. The amount of catalyst added and the reaction temperature must be the same for each batch. When the catalyst and / or cocatalyst is added dropwise, the rate of dropping must be the same for each batch.

In the present invention, a solvent may or may not be used at the time of the isocyanuration reaction.

The solvent used for the nullation reaction in the present invention is preferably an isocyanate group non-reactive solvent. Examples of isocyanate group non-reactive solvents include ethyl acetate,
Examples include, but are not limited to, butyl acetate, toluene, xylene, tetrahydrofuran, 1,4-dioxane, n-hexane and the like. When using a solvent, it is necessary to remove the dissolved carbon dioxide of the solvent before the reaction. In addition, since the water content of the solvent reacts with the isocyanate to produce undesirable urea, it must be removed. The use of a solvent is not preferred because it costs industrially.

The reaction is stopped when the desired conversion has been reached. As a method for stopping the reaction, it is preferable to add an acidic substance. Patent Application No. 9-171 filed and filed by the present inventors earlier
It is more preferable to use an acidic phosphoric acid ester containing an alkoxy group or an alkylene oxide group described in JP-A-792, since no cloudiness occurs.

[0030]

The present invention will be described below in more detail with reference to examples, but the method of the present invention is not limited to the examples. Example 1 NBDI3 containing 450 ppm by weight of carbon dioxide in a four-necked flask equipped with a reflux condenser, a thermometer and a stirrer
Then, 00 g, 0.6 g of triphenyl phosphite, and 0.03 g of dibutyltin dilaurate were charged, and the pressure was adjusted to 1.3 KPa as a deaeration operation, and then nitrogen gas was blown into the NBDI mixture to depressurize three times. Then 4
Nitrogen gas was bubbled into the NBDI mixture at a rate of 00 ml / min for 1 hour. As a result of measurement, the carbon dioxide concentration was 8 weight p.
pm or less (lower limit of detection: 8 ppm by weight). The temperature was raised to 45 ° C. while stirring the inside of the reactor under a nitrogen stream, and 0.01 g of potassium fluoride mixed in advance and an average molecular weight of 4
00 polyethylene glycol (PEG 400) 2.4
9 g were added dropwise over 3 hours. Immediately, 0.1 g of dibutoxyethyl phosphate was added to stop the reaction. As a result of analysis by gas chromatography, the reaction conversion rate was 48.
%Met.

Example 2 NBDI containing 1100 ppm by weight of carbon dioxide in a four-necked flask equipped with a reflux condenser, a thermometer and a stirrer
300 g, 0.6 g of triphenyl phosphite and 0.03 g of dibutyltin dilaurate were charged, the pressure was adjusted to 1.3 KPa as a deaeration operation, and then nitrogen gas was blown into the NBDI mixture to depressurize three times. afterwards,
Nitrogen gas was bubbled into the NBDI mixture at a rate of 400 ml / min for 1 hour. As a result of the measurement, the carbon dioxide concentration was 8 ppm by weight or less (lower detection limit: 8 ppm by weight). The temperature was raised to 45 ° C. while stirring the inside of the reactor under a nitrogen stream, and 0.01 g of potassium fluoride and polyethylene glycol (PEG400) having an average molecular weight of 400 were mixed in advance.
49 g were added dropwise over 3 hours. Immediately, 0.1 g of dibutoxyethyl phosphate was added to stop the reaction.
As a result of analysis by gas chromatography, the reaction conversion rate was 4
8%.

Comparative Example 1 NBDI3 containing 450 ppm by weight of carbon dioxide in a four-necked flask equipped with a reflux condenser, a thermometer and a stirrer
00 g, triphenyl phosphite 0.6 g and dibutyl tin dilaurate 0.03 g, and nitrogen gas was supplied at a rate of 400 ml / min for 1 hour as a degassing operation by NBD.
Blown into the I mixture. As a result of the measurement, the carbon dioxide concentration was 94 ppm by weight. The temperature was raised to 45 ° C. while stirring the inside of the reactor under a nitrogen stream, and 0.01 g of potassium fluoride previously mixed and 2.49 g of polyethylene glycol (PEG400) having an average molecular weight of 400 were added dropwise over 3 hours. Immediately, 0.1 g of dibutoxyethyl phosphate was added to stop the reaction. As a result of analysis by gas chromatography, the reaction conversion rate was 28%.

Comparative Example 2 NBDI containing 2814 ppm by weight of carbon dioxide in a four-necked flask equipped with a reflux condenser, a thermometer and a stirrer
300 g, 0.6 g of triphenyl phosphite and 0.03 g of dibutyltin dilaurate were charged, the temperature was raised to 45 ° C. while stirring the reactor under a nitrogen stream, and 0.01 g of potassium fluoride mixed in advance with an average molecular weight of 0.01 g. 400 polyethylene glycol (PEG 400)
49 g were added dropwise over 3 hours. Immediately, 0.1 g of dibutoxyethyl phosphate was added to stop the reaction.
As a result of analysis by gas chromatography, the reaction conversion rate was 2
%Met.

[0034]

According to the present invention, when producing a polyisocyanate containing an isocyanurate ring, the concentration of dissolved carbon dioxide in the isocyanate is kept at 20 ppm by weight or less, so that the isocyanate can be produced at a constant reaction rate with reproducibility in each batch. A method that can be nullified could be provided.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Satoshi Tsuruta 30 Asamuta-cho, Omuta-shi, Fukuoka Mitsui Chemicals, Inc. 72) Inventor Joji Morisaki 30 Asamuta-cho, Omuta-shi, Fukuoka Prefecture Mitsui Chemicals Co., Ltd. DB04 DG03 HA01 HA04 HA07 HA11 HA14 HC03 HC12 HC13 HC17 HC22 HC46 HC52 HC54 HC61 HC64 HC67 HC71 HC73 JA01 KA01 KB03 KC02 KC17 KD04 KD12 KD16 KE01 KE02 QD03 RA07 RA11

Claims (6)

[Claims] 1. One or two selected from (1) a polyethylene oxide compound, (2) a quaternary ammonium salt, and (3) a phosphonium compound together with potassium fluoride using an isocyanate containing 20 ppm by weight or less of carbon dioxide as a catalyst. A method for producing an isocyanurate group-containing polyisocyanate, wherein the isocyanuration is performed using a combination of two or more kinds and further using a dialkyltin compound as a promoter. 2. One or two selected from (1) a polyethylene oxide compound, (2) a quaternary ammonium salt, and (3) a phosphonium compound together with potassium fluoride using an isocyanate containing 8 ppm by weight or less of carbon dioxide as a catalyst. A method for producing an isocyanurate group-containing polyisocyanate, wherein the isocyanuration is performed using a combination of two or more kinds and further using a dialkyltin compound as a promoter. 3. The dialkyltin compound is a compound selected from the group consisting of dialkyltin dicarboxylates, dialkyltin dialkoxides, dialkyltin dithioalkoxides, dialkyltin oxides, and dialkyltin sulfides. Item 3. The production method according to Item 1 or 2. 4. The method according to claim 1, wherein the dialkyltin compound is a dialkyltin dicarboxylate. 5. The method according to claim 1, wherein the dialkyltin compound is di-n-butyltin dilaurate. 6. The method according to claim 1, wherein the isocyanate is 2,5 (6) -diisocyanatomethylbicyclo [2,2,1] heptane.