CN115926104A - Isophorone diisocyanate composition with moderate reactivity with alcohols - Google Patents

Abstract

The invention relates to an isophorone diisocyanate composition (IPDI) and application thereof, wherein the content of demethylated isophorone diisocyanate (H-IPDI) in the isophorone diisocyanate composition is 0.0005-0.0400%. The IPDI provided by the invention has moderate reaction activity when reacting with alcohols, the obtained reaction liquid has lower color number and turbidity, and less residual monomers.

Description

Isophorone diisocyanate composition with moderate reactivity with alcohols

Technical Field

The invention provides an isophorone diisocyanate composition with moderate reactivity with alcohols.

Background

Isophorone diisocyanate (IPDI for short) is colorless or pale yellow liquid at normal temperature, is aliphatic isocyanate and alicyclic isocyanate, has lower reaction activity than aromatic isocyanate, lower vapor pressure and lower toxicity than isocyanate. Due to no benzene ring in the structure, the modified polyurethane has excellent weather resistance, and can be used for preparing high-grade polyurethane materials with light stability, weather resistance and excellent mechanical properties, such as elastomers, aqueous polyurethane dispersions, UV resins and the like. IPDI can also be self-polymerized to generate polyfunctional group polyisocyanate, and the coating prepared by the IPDI has quick surface drying and excellent application in automobile refinishing paint. In the above applications, the requirements for various compositions and impurity contents in the IPDI monomer are relatively strict.

With the environmental protection concept being gradually deepened, the VOC volatilization problem in the use process of the isocyanate monomer in the market is more and more emphasized. In order to reduce the volatilization of the solvent during the use process, CN94108263.6 adopts a means of reacting isocyanate monomer with polyol to form prepolymer, which is more and more popular in the market because the molecular weight of the prepolymer is relatively large and the VOC volatilization amount during the use process is relatively small.

In the case of IPDI, due to the activity difference between two NCO groups, NCO with higher activity is involved in the reaction at the early stage of the reaction process with polyol, and NCO with lower activity is involved in the reaction at the later stage, but the viscosity of the system is gradually increased at the later stage of the reaction, and the dispersive mixing effect between IPDI and polyol is poor, so that the required reaction time is relatively long, and on the other hand, the local molecular and energy aggregation caused by the viscosity increase can cause excessive polymerization reaction, thereby causing the turbidity of the reaction liquid.

To solve this problem, DD151466A1 provides a solution in which the reaction is carried out in a solvent, but this is followed by a desolventizing operation and also by a part of the solvent remaining in the prepolymer, which volatilizes VOCs during subsequent use. CN94108263.6 adopts a solution to control 2% IPDI monomer residue to reduce the viscosity of the reaction system, thereby promoting the reaction between NCO and polyol, but the residual IPDI also has a certain VOC volatilization, so it is not an optimal solution from the environmental point of view. In addition, the viscosity is reduced by raising the temperature, but the color number of IPDI monomer and prepolymer is increased by long time high temperature retention, which affects the performance of the IPDI monomer and prepolymer in advanced applications, and the problem is also existed by high temperature separation.

Therefore, it is of great significance to develop an IPDI monomer which has moderate activity, less residual monomer of prepolymer after reaction with polyol and lower turbidity and color number of the prepolymer.

Disclosure of Invention

In view of the above problems in the prior art, the present invention is directed to developing an isophorone diisocyanate composition with moderate reactivity with alcohols, which has less residual monomers in the prepolymer after the reaction of IPDI composition with polyol, and lower turbidity and color number of the prepolymer.

In order to achieve the purpose, the invention adopts the following technical scheme:

an isophorone diisocyanate (IPDI) composition, wherein the content of demethylated isophorone diisocyanate (H-IPDI) is from 0.0005 to 0.0400 wt.%, preferably from 0.0010 to 0.0200 wt.%, more preferably from 0.0020 to 0.0100 wt.%.

The structural general formula of the demethylated isophorone diisocyanate (H-IPDI) is as follows:

wherein R is ₁ 、R ₂ Is H or CH ₃ And is not simultaneously CH ₃ ；

The structure of the demethylated isophorone diisocyanate (H-IPDI) is more preferably the following structure:

the preparation method of the isophorone dicyanate composition has no specific requirements, and the isophorone dicyanate composition with the composition can be obtained by any realizable mode in the prior art.

The invention can be realized by the following scheme:

the first scheme comprises the following steps: adding H-IPDI compound into IPDI, or mixing IPDI composition with high concentration H-IPDI with conventional IPDI;

scheme II: adding H-IPDA compounds into IPDA, and then carrying out phosgenation reaction to obtain the IPDI composition with the specification;

in some embodiments of the present invention, scheme two is used, therefore, one of the methods for preparing the IPDI composition of the present invention is to limit the content of demethylated isophoronediamine (H-IPDA) in the starting IPDA to above 0.0005%, with an upper limit higher than 0.04%;

since the separation of the dealkylation product H-IPDA from IPDA is difficult, for example, patent CN107304168A mentions that the separation of IPDA is divided into two steps, the low-boiling components including hydrogen, inert gas, ammonia and low-boiling impurities (low-boiling component separation) are first separated in a first distillation, and then the organic residue (high-boiling component) is separated via a second purification, for example, a vacuum distillation column to obtain pure isophoronediamine. In the process of purifying IPDA, H-IPDA is enriched and extracted from the oil phase of the light component, so that the content of H-IPDA in the conventional IPDA is extremely low or even none, and further the content of H-IPDI in the conventional IPDI obtained by the subsequent phosgenation reaction is extremely low or even none;

thus, in some embodiments, IPDA compositions having an H-IPDA content of greater than 0.04% may be blended with conventional IPDA to provide IPDA compositions having an H-IPDA content of from 0.0005% to 0.0400%, preferably from 0.0010% to 0.0200%, more preferably from 0.0020% to 0.0100%, and further phosgenation may provide IPDI compositions having an H-IPDI content of from 0.0005% to 0.0400%, preferably from 0.0010% to 0.0200%, more preferably from 0.0020% to 0.0100%;

or adding a certain amount of H-IPDA into conventional IPDA to obtain an IPDA composition with the H-IPDA content higher than 0.04%, directly carrying out phosgenation to obtain an IPDI composition with the H-IPDI content higher than 0.04%, and then blending with conventional H-IPDI to obtain the IPDI composition with the H-IPDI content of 0.0005-0.0400%, preferably 0.0010-0.0200%, more preferably 0.0020-0.0100%.

Other methods of controlling H-IPDI are possible and are not specifically enumerated in the present invention. The above methods may be used in combination or alone, and the present invention is not limited to the manner of obtaining the IPDI composition.

The content of the demethylated isophorone diisocyanate in the isophorone diisocyanate composition can be analyzed by adopting a gas chromatography method for sample injection, and the invention has no specific requirements, and if the method adopted in some specific examples is as follows: the sample is dissolved by solvent (preferably dichloromethane), and then is injected by gas chromatography for analysis, detected by hydrogen ion flame detector (FID), and quantitatively calculated by area normalization method.

According to the research of the inventor, the IPDI composition containing more than 0.0005% of H-IPDI has relatively moderate reaction activity with the polyol. Presumably, the IPDI composition contains one or more methyl groups on the six-membered ring of H-IPDI which is less than that of the conventional IPDI, so that the NCO activity of H-IPDI is slightly increased, the H-IPDI can react with polyhydric alcohol more easily when reacting with the polyhydric alcohol, and the heat released by the reaction of H-IPDI and the polyhydric alcohol at the initial stage of the reaction further initiates the reaction of IPDI and the polyhydric alcohol, so that the reaction efficiency of the IPDI composition and the polyhydric alcohol is improved, and excessive monomer residue caused by low efficiency of the reaction process is avoided; however, when the content of H-IPDI in the IPDI composition is too high, the heat released by the reaction between H-IPDI and polyol at the initial stage is too large, which may cause the reaction to be accelerated or even out of control, and further cause the viscosity of the alcohol-modified product to be too large or even turbidity, thereby affecting the mixing of IPDI and polyol, resulting in a longer reaction time, and even causing the color number of the reaction solution to be higher. Therefore, the invention controls the content of H-IPDI within 0.04%, thereby controlling the reaction efficiency of IPDI composition and polyhydric alcohol within a proper range.

The invention therefore defines that the content of H-IPDI in the IPDI composition is defined to be 0.0005-0.0400%, preferably 0.0010-0.0200%, more preferably 0.0020-0.0100%.

Compared with the prior art, the isophorone diisocyanate composition provided by the invention has the following beneficial effects:

1. the IPDI composition provided by the invention has moderate reaction activity with polyhydric alcohol;

2. the prepolymer obtained after the reaction has a lower color number and less residual monomers.

Detailed Description

The technical solution of the present invention is further explained by the following embodiments. It should be understood by those skilled in the art that the examples are only for the understanding of the present invention and should not be construed as the specific limitation of the present invention. The polypropylene glycol used in the examples was produced by Wanhua chemical group Ltd, and its specification was PPG-2000.

The content of the demethylated isophorone diisocyanate (H-IPDI) in the isophorone diisocyanate composition is analyzed by adopting a gas chromatograph method through sample injection, and the method comprises the following steps: the sample is dissolved by using dichloromethane, then is injected and analyzed by using a gas chromatography method, is detected by using a hydrogen ion flame detector (FID), and is quantitatively calculated by using an area normalization method.

The chromatographic conditions were as follows:

carrier gas: purified and dried high-purity nitrogen (the purity is more than or equal to 99.999%);

combustion gas: hydrogen (purity is more than or equal to 99.999 percent) and the flow rate is 40mL/min;

combustion-supporting gas: the flow rate of the purified and dried air is 400mL/min;

tail blowing: nitrogen with the flow rate of 30mL/min;

column flow rate: 1.06mL/min;

the split ratio is as follows: 30;

column temperature (temperature programmed): keeping at 140 deg.C for 0min, heating to 220 deg.C at 10 deg.C/min, keeping for 1min, heating to 260 deg.C at 5 deg.C/min, keeping for 0min, heating to 280 deg.C at 10 deg.C/min, and keeping for 1min;

sample inlet temperature: 270 ℃;

detector temperature: 290 ℃;

sample introduction amount: 0.2. Mu.L.

The quantitative analysis of the IPDA containing H-IPDA in the invention is carried out on a gas chromatography, and the analysis conditions of the gas chromatography are as follows:

a chromatographic column: agilent HP-5 (specification 30m 0.32mm 0.25mm); sample inlet temperature: 280 ℃; the split ratio is as follows: 30; column flow rate: 1.5ml/min; column temperature: keeping the temperature at 100 ℃ for 0.5min, raising the temperature to 260 ℃ at 15 ℃/min, and keeping the temperature for 8min; temperature of the detector: 280 ℃; h2 flow rate: 35ml/min.

Example 1 preparation of IPDI compositions with different H-IPDI contents

Step I: synthesis of Isophoronediamine compositions

The synthesis of IPDA was carried out by the method provided in patent CN109761855A in the following steps:

(1) 200kg/h of isophorone is sent to a preheater to be preheated to the reaction temperature of 120 ℃, and then is respectively sent to a reactor disclosed in embodiment 1 of CN103301799B and under the operation condition with the molar ratio of 2;

(2) Reacting the obtained isophorone nitrile, ammonia gas and hydrogen in the presence of a catalyst, and specifically comprising the following steps:

a) Reacting the isophorone nitrile obtained in the step (1) with ammonia gas in a tubular reactor at 60 DEG C

Under the conditions of the temperature and the absolute pressure of 15MPa, the molar ratio of ammonia gas to isophorone nitrile is 50;

b) In the presence of hydrogenation catalyst Raney cobalt, the space velocity of the catalyst is 1.5 g of 3-cyano-3, 5-trimethylcyclohexanone/(ml catalyst. H), hydrogen and NH are added ₃ Mixing the 3-cyano-3, 5-trimethylcyclohexylimine obtained in the step a) in a 3% KOH-ethanol solution for reaction, and carrying out the reaction at the temperature of 80 ℃ and under the absolute pressure of 18MPa to obtain a product containing 3-aminomethyl-3, 5-trimethylcyclohexylamine (IPDA for short) and 3-cyano-3, 5-trimethylcyclohexylamine;

in step b), of reacting the KOH-ethanol solution with added isophorone nitrileThe mass ratio of 1 ₃ Molar ratio to isophorone nitrile 50, hydrogen to isophorone nitrile 80;

c) In the presence of hydrogenation catalyst Raney cobalt, the space velocity of the catalyst is 1.8 g of 3-cyano-3, 5-trimethylcyclohexanone/(ml catalyst hour), hydrogen and NH are added ₃ And b) mixing the product containing the 3-aminomethyl-3, 5-trimethylcyclohexylamine and the 3-cyano-3, 5-trimethylcyclohexylamine in a 3% acetic acid-ethanol solution for reaction, wherein the reaction is carried out at the temperature of 120 ℃ and the absolute pressure of 18MPa, and the 3-cyano-3, 5-trimethylcyclohexylamine is converted into the 3-aminomethyl-3, 5-trimethylcyclohexylamine.

In step c), the mass ratio of the acetic acid-ethanol solution to the IPN obtained in step 1) is 1.

Step II: preparation of Isophoronediamine compositions with different H-IPDA contents 3-aminomethyl-3, 5-trimethylcyclohexylamine obtained in step I is purified, and the H-IPDA (formula 1, the same below) content is adjusted, the specific steps are as follows:

a) The method provided by Chinese patent CN107304168A is adopted to purify isophorone diamine to obtain a conventional IPDA composition, wherein the content of H-IPDA is 0.0001%, and meanwhile, an oil phase of a light component is obtained.

b) Rectifying the oil phase of the light component obtained in the step a), wherein the rectifying process adopts a rectifying tower with 15 tower plates to rectify, the temperature of a tower bottom is 160-200 ℃, collecting and collecting fractions at the stage of 160-185 ℃, and analyzing the fractions, wherein the content of H-IPDA is 98.5%, and the content of IPDA is 1.5%.

c) Adding the H-IPDA obtained in step b) to the conventional IPDA composition obtained in step a) to obtain IPDA compositions having H-IPDA contents of 0.0003%, 0.0008%, 0.0015%, 0.0040%, 0.0060%, 0.0080%, 0.0150%, 0.0300%, 0.0500% and 0.1000%, respectively.

Step III: preparation of Isophorone diisocyanate compositions having different H-IPDI contents IPDI compositions having different H-IPDI contents were prepared by reacting the conventional IPDA compositions obtained in step II (H-IPDA content of 0.0001%) and IPDA compositions having respective H-IPDA contents of 0.0003%, 0.0008%, 0.0015%, 0.0040%, 0.0060%, 0.0080%, 0.0150%, 0.0300%, 0.0500%, 0.1000% with phosgene.

The specific method comprises the following steps: gasifying and heating IPDA to 355 ℃ by using the heater mentioned in the embodiment 1 in the Chinese patent CN105214568A, and continuously adding gaseous phosgene heated to 355 ℃ into a reactor for reaction through respective feeding pipes under the protection of nitrogen, wherein the absolute pressure of the reaction is 0.05MPa, and the temperature is 360 ℃; wherein the feeding amount of IPDA is 800Kg/h, and the feeding amount of phosgene is 3000Kg/h; rapidly cooling the reacted mixed gas to 100 ℃ by using an o-dichlorobenzene solution through a gas jet absorption device to obtain a photochemical liquid containing the product IPDI; removing excessive phosgene at 180 ℃ and under the absolute pressure of 0.1MPa to obtain an IPDI (isophorone diisocyanate) crude product without phosgene; and rectifying the crude product by a rectifying tower to obtain an IPDI composition product under the distillation range of 150-160 ℃ at 0.5 KPa.

The obtained IPDI composition products were subjected to gas phase analysis, and the H-IPDI contents were 0.0001% (sample 1), 0.0003% (sample 2), 0.0008% (sample 3), 0.0015% (sample 4), 0.0040% (sample 5), 0.0060% (sample 6), 0.0080% (sample 7), 0.0150% (sample 8), 0.0300% (sample 9), 0.0500% (sample 10), and 0.1000% (sample 11), respectively.

Sample 11 was mixed with sample 1 to obtain sample 12, and the H-IPDI content was 0.0051% in the gas phase analysis (sample 12).

Example 2 reaction evaluation of IPDI compositions with polyols

a) Diluting a catalyst dibutyltin dilaurate (T12) to 1% concentration by using toluene for later use;

b) Adding 67.5g of PPG-2000 with the water content of 300ppm into a 500ml reaction kettle, putting the reaction kettle into an oil bath at 82 ℃, starting stirring for preheating, wherein the stirring speed is 180r/min;

c) After the temperature in the reaction kettle reaches 80 ℃, respectively adding 0.3g of the catalyst T12 prepared in the step a) and 7.6g of the IPDI composition into the reaction kettle, and carrying out reaction;

d) Sampling every 5min in the reaction process to monitor the NCO content, judging that the reaction is stopped when the NCO content is not reduced any more, stopping heating, and recording the reaction time;

e) And when the temperature of the reaction kettle is reduced to room temperature, sampling reaction liquid obtained by GPC for area normalization, analyzing to obtain the content of residual monomers, and measuring the colorimetric value of the reaction liquid by the GB/T605-2006 method.

In the examples, 8 batches of IPDI compositions were tested using samples 3, 4, 5, 6, 7, 8, 9 and 12, respectively, to obtain different batches of reaction solutions.

Comparative example 1

The same procedure as in example 2 was followed, except that the IPDI compositions used were samples 1, 2, 10 and 11, respectively, to obtain different batches of reaction solutions.

Comparative example 2

A quantity of 3-isocyanatomethyl-5, 5-dimethylcyclohexyl isocyanate was prepared and added to sample 1 using the process provided in JP2000044527A to give an IPDI composition having a 3-isocyanatomethyl-5, 5-dimethylcyclohexyl isocyanate content of 0.008% (sample 13).

Evaluation tests were performed according to the method provided in example 2.

The H-IPDI contents of the 8 batches of example 2 and of the 5 IPDI compositions of comparative examples 1 and 2 and the quality of the reaction solutions obtained by reaction with the polyols were as follows:

note 1: wherein the content of 3-isocyanate methyl-5, 5-dimethyl cyclohexyl isocyanate is 0.008 percent.

The results in the table show that the reactivity of the isophorone diisocyanate composition of 8 batches tested in example 2 with polyol is moderate, the color number and turbidity of the obtained reaction liquid are low, the content of residual monomer is below 0.01%, and the advantages are obvious compared with the comparative example.

The present invention is illustrated in detail by the examples given above, but the present invention is not limited to the details given above, which means that the present invention is not limited to the details given above. It should be understood by those skilled in the art that any modifications of the present invention, equivalent substitutions of the raw materials of the product of the present invention, and the addition of auxiliary components, selection of specific modes, etc., are within the scope and disclosure of the present invention.

Claims (5)

1. An isophorone diisocyanate composition, wherein the content of demethylated isophorone diisocyanate in the isophorone diisocyanate composition is from 0.0005 to 0.0400wt%.

2. An isophorone diisocyanate composition according to claim 1, wherein the content of demethylated isophorone diisocyanate in the isophorone diisocyanate composition is 0.0010-0.0200wt%.

3. An isophorone diisocyanate composition according to claim 2, wherein the content of demethylated isophorone diisocyanate in the isophorone diisocyanate composition is 0.0020-0.0100wt%.

4. The isophorone diisocyanate composition of any one of claims 1-3, wherein the demethylated isophorone diisocyanate has the general structural formula:

wherein R is ₁ 、R ₂ Structure of H or CH ₃ And is not simultaneously CH ₃ 。

5. The isophorone diisocyanate composition of any one of claims 1-4, wherein the demethylated isophorone diisocyanate has the following structure:

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