Polyisocyanate composition

Abstract

This specification discloses a polyisocyanate composition comprising an isocyanurate of Structure A (methyl-substituted IPDI trimer) and an isocyanurate of Structure B (IPDI trimer). The defined molar ratio of the two isocyanurates improves solubility in non-polar solvents, which is advantageous for use by downstream customers.

Description

[Technical Field]

[0001] The present application relates to the polyisocyanate technical field, for example to polyisocyanate compositions. [Background technology]

[0002] The technology of modifying isophorone diisocyanate (IPDI) monomer under the action of a catalyst is well known in the art, for example, by carrying out a polymerization reaction or an alcohol modification reaction, and after reaching a desired conversion rate, removing the unreacted IPDI monomer by vacuum distillation or thin film evaporation, thereby obtaining a polyisocyanate composition product based on IPDI. For example, see US2004176562A1, US6093817, CN107827832, etc.

[0003] Polyisocyanate compositions prepared by IPDI polymerization have remarkable fast-drying properties and are widely used in the polyurethane coating industry. Furthermore, because polyisocyanate compositions prepared by IPDI are almost solid at room temperature, industrial customers generally use them by dissolving them in solvents.

[0004] In actual downstream use processes, it has been found that IPDI-based polyisocyanate compositions have relatively low solubility in non-polar solvents and are prone to increased turbidity, which will affect the use of downstream customers. Summary of the Invention [Problem to be solved by the invention]

[0005] The following is a summary of the subject matter described in detail herein. This summary is not intended to limit the scope of the claims.

[0006] In the course of actual research, researchers have discovered that when a polyisocyanate composition contains the following methyl-substituted specific structure A, the solubility of the composition in a non-polar solvent is improved. [Means for solving the problem]

[0007] In order to improve the solubility of non-polar solvents, the technical solutions adopted in the embodiments of this application are as follows:

[0008] A polyisocyanate composition comprising an isocyanurate of Structure A and an isocyanurate of Structure B, Structure A is shown below: TIFF2026505597000001.tif3770R'1, R'2, and R'3 are each selected from the following four structures, wherein at least one of R'1, R'2, and R'3 is selected from structure (I) or structure (II): TIFF2026505597000002.tif3364 TIFF2026505597000003.tif3564 TIFF2026505597000004.tif3064 TIFF2026505597000005.tif3264One, two, or three of the groups R1, R2, R3, R4, R5, R6, and R7 in the above structural formula are CH3, and the rest are oxygen.

[0009] Structure B is shown below: TIFF2026505597000006.tif3647Z1, Z2, and Z3 may be any one or two of the following two structures: TIFF2026505597000007.tif3064 TIFF2026505597000008.tif3164

[0010] The molar ratio of the isocyanurate of Structure A to the isocyanurate of Structure B is 0.0005 to 0.03.

[0011] In the polyisocyanate composition described in the present application, the molar ratio of the isocyanurate of Structure A to the isocyanurate of Structure B is 0.005 to 0.02.

[0012] When the molar ratio of the isocyanurate of Structure A to the isocyanurate of Structure B is equal to or greater than the lower limit, the solubility in non-polar solvents is improved, which is advantageous for coating films, and when it is equal to or less than the upper limit, the increase in viscosity in the solution state is suppressed, which is advantageous for downstream application.

[0013] In this application, Structure B is isophorone diisocyanate trimer, and Structure A is methyl-substituted isophorone diisocyanate trimer.

[0014] The method for controlling the molar ratio of the isocyanurate of Structure A to the isocyanurate of Structure B is not particularly limited as long as the purpose can be achieved. For example, the molar ratio of the present application can be directly obtained by a polymerization method of isophorone diisocyanate, or the molar ratio of the present application can be achieved by adding Structure A.

[0015] When the composition is prepared by a method for polymerizing isophorone diisocyanate, the contents of Structure A and Structure B in the final composition can be controlled by controlling the content of methyl-substituted isophorone diisocyanate in the raw material isophorone diisocyanate.

[0016] Here, the structure of the methyl-substituted isophorone diisocyanate (methyl-substituted IPDI) is as follows: JPEG2026505597000009.jpg3649 (wherein R1, R2, R3, R4, R5, R6, and R7 are defined as in Formula I and Formula II.)

[0017] The content of methyl-substituted isophorone diisocyanate can be adjusted during the preparation of isophorone diisocyanate to obtain isophorone diisocyanate monomer containing methyl-substituted isophorone diisocyanate, or can be controlled by addition before preparing the trimer.

[0018] The IPDI preparation process is as follows: isophorone nitrile is prepared from isophorone and hydrogen cyanide, which is then reacted with ammonia gas and hydrogen gas to produce isophorone diamine, which is then subjected to a phosgenation process to obtain IPDI. Research has shown that methyl-substituted IPDI monomers may be produced during the IPDI preparation process. The content of the methyl-substituted product in IPDI can be controlled by adjusting the reaction and / or separation conditions, such as the methylamine content in the ammonia gas feedstock, the chloride content in the hydrogenation catalyst, or the number and conditions of rectification. The molar ratio of these two compounds can also be adjusted by separately preparing and adding methyl-substituted isophorone diisocyanate trimer (Structure A).

[0019] For specific preparation methods of IPDI containing methyl-substituted isophorone diisocyanate, see CN115894857A.

[0020] In the present application, in the polyisocyanate composition based on isophorone diisocyanate, the mass content of the isocyanurate of Structure B is 50% to 75%, preferably 50% to 70%, more preferably 55% to 65%, and more preferably 59% to 63%. This content can be measured by gel chromatography.

[0021] In the present application, the mass content of isocyanate groups (-NCO) in the polyisocyanate composition based on isophorone diisocyanate is 16 to 18%, preferably 16.5 to 17.5%. On the one hand, the NCO group content in the composition must not be too low, as too low a content would be detrimental to the structural crosslinking of the coating film, and on the other hand, the NCO content must not be too high, as too high a content would reduce the hardness of the coating film.

[0022] In the present application, the polyisocyanate composition based on isophorone diisocyanate may be in the form of a solid or a solution dissolved in a solvent, Because the polyisocyanate compositions described herein are in a solid state at room temperature, typically 25°C, in some specific embodiments, the isophorone diisocyanate-based polyisocyanate compositions described herein can also be dissolved in a solvent to provide a solution of the polyisocyanate composition in solution in the solvent.

[0023] In the polyisocyanate composition solution of the present application, the solvent is any one or a combination of at least two selected from butyl acetate, ethyl acetate, solvent, toluene, xylene, propylene glycol methyl ether acetate, 2-heptanone, etc., Preferably, the mass proportion of the solvent is 28 to 32%, for example, 29%, 30%, or 31%, preferably 30%, relative to the total mass of the polyisocyanate composition solution being 100%. If the solvent content in the composition solution is too high, the economic benefits of downstream use will be reduced, while if the solvent content is too low, the solution viscosity will be too high, which will also be disadvantageous for downstream use.

[0024] Preferably, in a polyisocyanate composition solution corresponding to a solution state in which the polyisocyanate composition is dissolved in a solvent, the mass content of the NCO group is 11.2 to 12.8%, for example, 11.3%, 11.6%, 11.9%, 12.2%, 12.5%, 12.8%, and preferably 12%, when the total mass of the polyisocyanate composition solution is 100%.

[0025] In some specific embodiments, the polyisocyanate compositions based on isophorone diisocyanate of the present application have an isophorone diisocyanate monomer content of less than 0.5 wt %, e.g., 0.01 wt %, 0.05 wt %, 0.1 wt %, 0.2 wt %, 0.3 wt %, 0.4 wt %, preferably less than 0.35 wt %, more preferably less than 0.1 wt %, where the reduced IPDI monomer content is advantageous for downstream application safety.

[0026] The method for polymerizing isophorone diisocyanate is not limited as long as the composition of the polyisocyanate composition satisfies the above requirements of the present application.

[0027] According to the methods disclosed in the prior art, it can be prepared, for example, by the following method.

[0028] In the presence of a polymerization catalyst, isophorone diisocyanate is polymerized until the mass content of NCO groups in the system reaches 20 to 30%, for example, 24%, 25%, 26%, or 27%, at which point the reaction is terminated, and unreacted monomers are then removed to obtain the polyisocyanate composition based on isophorone diisocyanate.

[0029] The basic method for isocyanate polymerization is well known in the art. In a specific polymerization process, isophorone diisocyanate is first added to a round-bottom flask equipped with a reflux condenser, a stirrer, a thermometer, and a nitrogen inlet. The system is then heated to a predetermined reaction temperature range (e.g., 50 to 110°C, e.g., 70°C or 90°C), and then a catalyst solution is added dropwise. As is well known to those skilled in the art, the specific operating parameters and operating sequence of the polymerization reaction are common knowledge in the art and will not be described in detail here.

[0030] In some specific embodiments, the amount of the catalyst used is 0.001 to 0.1%, for example, 0.005%, 0.01%, 0.02%, 0.04%, 0.06%, 0.08%, preferably 0.01 to 0.03%, of the mass of isophorone diisocyanate.

[0031] The polymerization catalyst used in the present application is selected from (1) tetraalkylammonium hydroxides (e.g., tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrabutylammonium hydroxide, benzyltrimethylammonium hydroxide, etc.) or tetraalkylammonium organic acid salts (e.g., tetramethylammonium acetate, tetraethylammonium butyrate, etc.), (2) hydroxyalkylammonium (e.g., trimethylhydroxypropylammonium, trimethylhydroxyethylammonium, triethylhydroxypropylammonium, etc.) hydroxides or their organic acid (e.g., acetic acid, butyric acid, isooctanoic acid, etc.) salts, or (3) metal (e.g., tin, zinc, etc.) salts of alkylcarboxylic acids (e.g., acetic acid, capric acid, caprylic acid, etc.), preferably one or more of (1) or (2).

[0032] In some specific embodiments, the catalysts used herein are dissolved in an organic solvent to prepare a catalyst solution, which is then added to the system to catalyze the polymerization reaction.

[0033] Specifically, in the catalyst solution, the mass concentration of the catalyst is 1 to 40%, for example, 5%, 10%, 15%, 20%, 25%, 30%, or 35%, and preferably 10 to 30%.

[0034] Specifically, the organic solvent is selected from alcohol-based solvents, and is preferably any one or a combination of at least two of monoalcohols and diols. In the present application, the monoalcohol is any one or a combination of at least two selected from 1-propanol, 2-propanol, n-butanol, isobutanol, sec-butanol, tert-butanol, n-octyl alcohol, isooctyl alcohol, heptanol, n-butanol, hexanol, heptanol, and isooctyl alcohol, and the diol is any one or a combination of at least two selected from diethylene glycol, 1,3-butanediol, 1,6-hexanediol, 1,4-butanediol, 2-ethyl-1,6-hexanediol, and the like.

[0035] In some specific embodiments, the polymerization reaction can be terminated with a terminator when the NCO value in the system reaches 23 to 28%, for example, 24%, 25%, 26%, or 27%. Specifically, the molar ratio of the terminator to the polymerization catalyst is 1 to 1.1, for example, 1.02, 1.04, 1.06, or 1.08, and preferably 1. The terminator is any one or a combination of at least two selected from phosphate-based or benzenesulfonic acid-based terminators, for example, any one or a combination of at least two of dibutyl phosphate, dioctyl phosphate, or p-toluenesulfonic acid.

[0036] In some other embodiments, the polymerization reaction can be terminated by increasing the temperature and maintaining it for a predetermined period of time. In a specific implementation process, the system is heated to 120 to 130°C (e.g., 122°C, 124°C, 126°C, 128°C) and maintained at that temperature for 30 to 60 minutes (e.g., 35 minutes, 40 minutes, 45 minutes, 50 minutes, 55 minutes).

[0037] In some specific embodiments, an optional technical solution is to control the mass content of methyl-substituted IPDI in the raw material IPDI monomer to 0.01% to 0.27%, obtain a reaction solution under the above reaction conditions, and then remove unreacted isophorone diisocyanate monomer from the polymerization reaction system by thin-film evaporation. In some specific embodiments, the unreacted isophorone diisocyanate monomer from the reaction system is removed using a thin-film evaporator under conditions of 170 to 200°C and 10 to 200 PaA (e.g., 50 PaA, 100 PaA, 150 PaA), thereby obtaining the polyisocyanate composition of the present application.

[0038] Another optional technical solution is to directly polymerize enriched methyl-substituted IPDI according to the above method to obtain a polyisocyanate composition rich in Structure A, and then blend the composition rich in Structure A with a polyisocyanate composition rich in Structure B, thereby obtaining the polyisocyanate composition of the present application.

[0039] The polyisocyanate compositions based on the present IPDI can be used in applications such as automotive refinish coatings, automotive OEM topcoats, and rail transit coatings. [Effects of the Invention]

[0040] Compared with the prior art, the technical solutions of the embodiments of the present application have the beneficial effect of increasing the solvent types of non-polar solvents while ensuring appropriate viscosity for downstream application, which is advantageous for downstream customers' use.

[0041] Further aspects become apparent upon reading and understanding the detailed description. DETAILED DESCRIPTION OF THE INVENTION

[0042] For a better understanding of the present application, the present application will now be further described with reference to examples.

[0043] The main raw materials used in the following examples were sourced from the following sources. Other raw materials are commercially available unless otherwise specified.

[0044] The main raw materials used in the following examples were supplied by the following sources: Other raw materials are commercially available, unless otherwise specified.

[0045] Isophorone diisocyanate (IPDI): Wanhua Chemical n-Hexanol: Sigma-Aldrich, 98% Isooctyl alcohol: Sigma-Aldrich, 98% n-Butanol: Sigma-Aldrich, 99% 1,3-Butanediol: Sigma-Aldrich, 99% Trimethylhydroxypropylammonium ethylhexanoate: Sigma-Aldrich, 95% Benzyltrimethylammonium hydroxide: Sigma-Aldrich, 95% Tetrabutylammonium hydroxide: Sigma-Aldrich, 95% Tetrabutylammonium acetate: Sigma-Aldrich, 96% Dibutyl phosphate, Sigma-Aldrich, 97% Diisooctyl phosphate, Sigma-Aldrich, 96% p-Toluenesulfonic acid, Sigma-Aldrich, 95% Butyl acetate: Kokuyo Reagent Co., Ltd., 99% Solvent S100: A commercially available product manufactured by Kaho ▲An▼Rinsha. The main test methods used in each example of the present application are as follows.

[0046] 1. Test method for monomer content in polyisocyanate composition: GB / T 18446-2009 shall be adopted.

[0047] 2. Measurement of NCO group content: After neutralizing the isocyanate groups in the test sample with an excess of 2 mol / L di-n-butylamine, back titration is performed with 1 mol / L hydrochloric acid to obtain the NCO group content based on the total mass of the sample. The calculation formula is as follows: TIFF2026505597000010.tif1266Here, V is the volume (ml) of the hydrochloric acid standard solution used when titrating the sample, V0 is the volume (ml) of the hydrochloric acid standard solution used in the blank titration, c is the actual concentration of the hydrochloric acid standard solution (mol / L), 0.04202 is the mass (in grams) of isocyanate equivalent to 1.00 ml of standard hydrochloric acid solution [c(HCl) = 1.000 mol / L], m is the total mass of the sample (g).

[0048] 3. Test method for methyl-substituted IPDI content in IPDI monomer The content of methylated isophorone diisocyanate in the isophorone diisocyanate composition described herein can be analyzed by gas chromatography, i.e., a sample is dissolved in a solvent (preferably dichloromethane), then analyzed by gas chromatography, detected by a hydrogen ion flame detector (FID), and quantitatively calculated by the area normalization method. The chromatography conditions were as follows: Carrier gas: Purified, dry, high-purity nitrogen (purity ≥ 99.999%) Combustion gas: Hydrogen (purity ≥ 99.999%), flow rate 40 mL / min Combustion auxiliary gas: Purified and dried air, flow rate 400 mL / min Purge gas: Nitrogen, flow rate 30 mL / min Column flow rate: 1.06 mL / min Split ratio: 30:1 Column temperature (programmed temperature): hold at 140°C for 0 minutes, increase the temperature to 220°C at 10°C / min and hold for 1 minute, increase the temperature to 260°C at 5°C / min and hold for 0 minutes, increase the temperature to 280°C at 10°C / min and hold for 1 minute. Inlet temperature: 270℃ Detector temperature: 290℃ Injection volume: 0.2μL

[0049] 4. Molar ratio of Structure A to Structure B: The ratio of the isocyanurate structure formed by polymerization of methyl-substituted IPDI to the isocyanurate trimer (referred to as compound α) formed by polymerization of three IPDIs in the polyisocyanate composition is measured by the following method. Specifically, the terminal isocyanate groups of the polyisocyanate composition according to the present invention are converted into urethane using methanol, and the resulting composition is analyzed using a liquid chromatography mass spectrometer (LC / MS). The sample preparation and measurement methods are as follows. (1) Sample preparation method Weigh out 100 mg of the polyisocyanate composition and add methanol to make it 10 mg / mL. Then, leave it for 2 days to completely react the existing isocyanate groups with the methanol to prepare a methanol solution. (2)Measurement method The methanol solution obtained above is measured using the following equipment. ·LC Instrument: Waters ACQUITY UPLC Column: Phenomenex, Kinetex 2.6μXB-C18 100A (inner diameter 2.1 mm, length 50 mm) Column temperature: 40℃ Detector: 220 nm Flow rate: 0.3mL / min Mobile phase: Gradient of solution A and solution B: A = water (0.05% formic acid), B = acetonitrile (0.05% formic acid) Injection volume: 1μL MS Equipment: Waters, Synapt G2 Ionization: ESI Mode: Positive Scan range: m / z 250-2000 The methanol adduct of isocyanurate trimer (compound β) formed by polymerization of three IPDIs is detected by the detection ion (m / z) 762. In the isocyanurate structure formed by polymerization of methyl-substituted IPDI, the ion (m / z) position differs depending on the number of methyl substitutions. The ion peak positions (m / z) of the isocyanurate structures formed by polymerization of one, two, or three methyl-substituted IPDIs were 776, 790, and 804, and these were defined as compounds a, b, and c. The ion peak positions (m / z) of the isocyanurate structures formed by polymerization of four, five, and six methyl-substituted IPDIs were 818, 832, and 846, respectively, and these were defined as compounds d, e, and f. The ion peak positions (m / z) of the isocyanurate structures formed by polymerization of seven, eight, and nine methyl-substituted IPDIs are 860, 874, and 888, which are defined as compounds g, h, and i. The ratio of the peak area of ​​compounds a to i to the peak area of ​​compound β is calculated as the molar ratio of structure A to structure B.

[0050] 5. Evaluation method for solubility in non-polar solvents The polyisocyanate composition and Solvent S100 are mixed in a 1:1 mass ratio to obtain a diluent, which is then tested using a HACH 2100 turbidimeter. If the turbidity is 0.3 or less, the solubility is good. If the turbidity is greater than 0.3 and less than or equal to 0.6, the solubility is good. If the turbidity is greater than 0.6 and less than or equal to 0.9, the solubility is within the acceptable range. If the turbidity is above 0.9, the solubility is poor.

[0051] 6. Evaluation method for dissolution viscosity in polar solvents The polyisocyanate composition and butyl acetate are mixed in a mass ratio of 7:3 to obtain a solution product, which is subjected to a viscosity test at 25°C using a Brookfield DV2T viscometer. If the viscosity at 25°C is 600 cP or less, it is superior to downstream construction. If the viscosity at 25°C is 800 cP or less, it is suitable for downstream application. If the viscosity at 25°C is 1000cP or less, it is recommended for downstream application. If the viscosity at 25°C exceeds 1000 cP, it may cause problems with downstream application.

[0052] 7. Test method for solid content: A sample of the composition solution is accurately weighed (approximately 0.5 g), placed in an aluminum foil dish (weigh the mass accurately), and left in an oven at 120°C for 2 hours. It is then removed, cooled, and weighed. Solid content = (weight after drying - weight of aluminum foil dish) / sample weight × 100%.

[0053] Example 1 Preparation of catalyst solution: Tetrabutylammonium hydroxide was dissolved in n-butanol to prepare a solution with a concentration of 20 wt %. 1000 g of IPDI (0.01% by mass of methyl-substituted IPDI) was placed in a round-bottom flask equipped with a reflux condenser, a thermometer, and a nitrogen inlet. The reaction system was heated to 70°C, and the catalyst solution prepared above was added dropwise to the reaction system while stirring (the amount of catalyst used was 0.015% of the mass of IPDI). The reaction temperature was controlled between 70 and 80°C to carry out the polymerization reaction. When the NCO mass content of the reaction system reached 28%, an equimolar amount of dibutyl phosphate was added to the catalyst to terminate the reaction. Using a thin-film evaporator, unreacted isophorone diisocyanate monomer was removed by evaporation from the polymerization reaction liquid under conditions of a temperature of 185°C and an absolute pressure of 50 Pa. The resulting mixture was held for 10 minutes and then dissolved in butyl acetate so that the isophorone diisocyanate monomer content was 0.34 wt% and the IPDI trimer (i.e., isocyanate of Structure B) mass content was 68%, yielding a solution product with a solids content of 70 wt%, giving polyisocyanate composition solution 1.

[0054] Example 2 Preparation of catalyst solution: Trimethylhydroxypropylammonium ethylhexanoate was dissolved in isooctyl alcohol to prepare a solution with a concentration of 30 wt %. 1000 g of IPDI (0.08% by mass of methyl-substituted IPDI) was placed in a round-bottom flask equipped with a reflux condenser, a thermometer, and a nitrogen inlet. The reaction system was heated to 80°C, and the catalyst solution prepared above was added dropwise to the reaction system while stirring (the amount of catalyst used was 0.016% of the mass of IPDI). The reaction temperature was controlled between 80 and 90°C to carry out the polymerization reaction. When the NCO mass content of the reaction system was 25%, the reaction was terminated by adding an equimolar amount of diisooctyl phosphate to the catalyst. Using a thin-film evaporator, the unreacted isophorone diisocyanate monomer in the polymerization reaction liquid was removed by evaporation under conditions of a temperature of 185°C and an absolute pressure of 50 Pa, and the resulting mixture was held for 15 minutes. The resulting mixture was then dissolved in butyl acetate so that the isophorone diisocyanate monomer content was 0.32 wt% and the mass content of IPDI trimer (i.e., isocyanate of Structure B) was 62%, yielding a solution product with a solids content of 70 wt%, giving polyisocyanate composition solution 2.

[0055] Example 3 Preparation of catalyst solution: Benzyltrimethylammonium hydroxide was dissolved in n-hexanol to prepare a solution with a concentration of 1 wt %. 1000 g of IPDI (0.18% by mass of methyl-substituted IPDI) was placed in a round-bottom flask equipped with a reflux condenser, a thermometer, a thermometer, and a nitrogen inlet. The reaction system was heated to 60°C, and the catalyst solution prepared above was added dropwise to the reaction system with stirring (the amount of catalyst used was 0.015% of the mass of IPDI). The reaction temperature was controlled between 60 and 70°C to carry out the polymerization reaction. When the NCO mass content of the reaction system was 25%, the reaction was terminated by adding diisooctyl phosphate at a molar ratio of 1.1 to the catalyst. Using a thin-film evaporator, the unreacted isophorone diisocyanate monomer in the polymerization reaction liquid was removed by evaporation under conditions of a temperature of 200°C and an absolute pressure of 100 Pa, and the resulting mixture was held for 10 minutes. The resulting mixture was then dissolved in butyl acetate so that the isophorone diisocyanate monomer content was 0.33 wt% and the mass content of IPDI trimer (i.e., isocyanate of Structure B) was 62%, yielding a solution product with a solids content of 70 wt%, giving polyisocyanate composition solution 3.

[0056] Example 4 Preparation of catalyst solution: Tetrabutylammonium acetate was dissolved in 1,3-butanediol to prepare a solution with a concentration of 10 wt %. 1000 g of IPDI (0.35% by mass of methyl-substituted IPDI) was placed in a round-bottom flask equipped with a reflux condenser, a thermometer, and a nitrogen inlet. The reaction system was heated to 70°C, and the catalyst solution prepared above was added dropwise to the reaction system while stirring (the amount of catalyst used was 0.0155% of the mass of IPDI). The reaction temperature was controlled between 70 and 80°C to carry out the polymerization reaction. When the NCO mass content of the reaction system was 23%, the reaction was terminated by adding an equimolar amount of p-toluenesulfonic acid to the catalyst. Using a thin-film evaporator, the unreacted isophorone diisocyanate monomer in the polymerization reaction liquid was removed by evaporation under conditions of a temperature of 200°C and an absolute pressure of 100 Pa, and the resulting mixture was held for 10 minutes. The resulting mixture was then dissolved in Solvent S100 so that the isophorone diisocyanate monomer content was 0.3 wt% and the mass content of IPDI trimer (i.e., isocyanate of Structure B) was 58%, yielding a solution product with a solids content of 70 wt% and polyisocyanate composition solution 4.

[0057] Example 5 Preparation of catalyst solution: Benzyltrimethylammonium hydroxide was dissolved in isooctyl alcohol to prepare a solution with a concentration of 5 wt %. 1000 g of IPDI (0.55% methyl-substituted IPDI mass content) was placed in a round-bottom flask equipped with a reflux condenser, a thermometer, and a nitrogen inlet. The reaction system was heated to 90°C, and the catalyst solution prepared above was added dropwise to the reaction system with stirring (the amount of catalyst used was 0.016% of the IPDI mass). The reaction temperature was controlled between 100 and 110°C to carry out the polymerization reaction. When the NCO mass content of the reaction solution was 26%, the system was heated to 130°C (at a heating rate of 1°C / min) and maintained for 30 minutes after heating to obtain a polymerization reaction solution. Using a thin-film evaporator, the unreacted isophorone diisocyanate monomer in the polymerization reaction liquid was removed by evaporation under conditions of a temperature of 190°C and an absolute pressure of 50 Pa, and the resulting mixture was held for 10 minutes. The resulting mixture was dissolved in butyl acetate so that the isophorone diisocyanate monomer content was 0.3 wt% and the mass content of IPDI trimer (i.e., isocyanate of Structure B) was 64%, yielding a solution product with a solids content of 70 wt%, giving polyisocyanate composition solution 5.

[0058] Comparative Example 1 Preparation of catalyst solution: same as in Example 3. 1000 g of IPDI (0.002% methyl-substituted IPDI mass content) was placed in a round-bottom flask equipped with a reflux condenser, a thermometer, and a nitrogen inlet. The reaction system was heated to 70°C, and the catalyst solution prepared above was added dropwise to the reaction system while stirring (the amount of catalyst used was 0.015% of the IPDI mass). The reaction temperature was controlled between 100 and 110°C to carry out the polymerization reaction. When the NCO mass content of the reaction solution was 26%, the reaction was terminated by adding an equimolar amount of dibutyl phosphate to tetrabutylammonium difluoride, yielding a polymerization reaction solution. Using a thin-film evaporator, the unreacted isophorone diisocyanate monomer in the polymerization reaction liquid was removed by evaporation under conditions of a temperature of 200°C and an absolute pressure of 100 Pa, and the resulting solution was dissolved in butyl acetate so that the unreacted isophorone diisocyanate monomer content was 0.33 wt% and the mass content of IPDI trimer (i.e., isocyanate of Structure B) was 64%, yielding a solution product with a solids content of 70% and Polyisocyanate Composition 3-1.

[0059] Comparative Example 2 Preparation of catalyst solution: same as in Example 3. 1000 g of IPDI (0.60% by mass of methyl-substituted IPDI) was placed in a round-bottom flask equipped with a reflux condenser, a thermometer, and a nitrogen inlet. The reaction system was heated to 70°C, and the catalyst solution prepared above was added dropwise to the reaction system while stirring (the amount of catalyst used was 0.015% of the mass of IPDI). The reaction temperature was controlled between 70 and 80°C to carry out the polymerization reaction. When the NCO mass content of the reaction solution was 25%, the reaction was terminated by adding an equimolar amount of dibutyl phosphate to tetrabutylammonium difluoride, yielding a polymerization reaction solution. Using a thin-film evaporator, the unreacted isophorone diisocyanate monomer in the polymerization reaction liquid was removed by evaporation under conditions of a temperature of 200°C and an absolute pressure of 100 Pa, and the resulting solution was dissolved in butyl acetate so that the isophorone diisocyanate monomer content was 0.33 wt% and the mass content of IPDI trimer (i.e., isocyanate of Structure B) was 62%, yielding a solution product with a solids content of 70% and Polyisocyanate Composition 3-2.

[0060] The compositions and properties of the polyisocyanate compositions prepared in the above Examples and Comparative Examples were tested, and the results are shown in Table 1.

[0061] [Table 1]

[0062] The above results indicate that controlling the molar ratio of Structure A / Structure B isocyanurate can enhance solubility in non-polar solvents while avoiding an increase in downstream application viscosity.

[0063] While the present invention has been described in detail above for purposes of illustration, these are by way of example only and modifications may be made thereto by those skilled in the art without departing from the spirit and scope of the invention, the scope of which is defined by the claims that follow.

Claims

1. 1. A polyisocyanate composition comprising: comprising an isocyanurate of structure A and an isocyanurate of structure B, Structure A is shown below: R' 1 , R' 2 , R' 3 are each selected from the following four structures, 1 , R' 2 , R' 3 is selected from structure (I) or structure (II), R in the above structural formula 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 one, two or three groups are CH 3 and the remainder is hydrogen, Structure B is shown below: Z 1 , Z 2 , Z 3 is one or both of the following two structures: A polyisocyanate composition, wherein the molar ratio of the isocyanurate of Structure A to the isocyanurate of Structure B is 0.0005 to 0.

03.

2. 2. The polyisocyanate composition of claim 1, wherein the molar ratio of the isocyanurate of Structure A to the isocyanurate of Structure B is 0.005 to 0.

02.

3. 3. The polyisocyanate composition according to claim 1 or 2, wherein the mass content of the isocyanurate of Structure B is 50% to 75%, preferably 50% to 70%, more preferably 55 to 65%, more preferably 59% to 63%.

4. 4. Polyisocyanate composition according to claim 1, wherein the mass content of isocyanate groups is 16 to 18%, preferably 16.5 to 17.5%.

5. The polyisocyanate composition according to any one of claims 1 to 4, wherein the polyisocyanate composition solution is obtained by dissolving the polyisocyanate composition in a solvent, and the solvent is any one or a combination of at least two selected from butyl acetate, ethyl acetate, solvent, toluene, xylene, propylene glycol methyl ether acetate, 2-heptanone, and the like.

6. The polyisocyanate composition according to claim 5, wherein the mass ratio of the solvent is 28 to 32% relative to the total mass of the polyisocyanate composition solution being 100%.

7. 7. The polyisocyanate composition according to claim 5, wherein a polyisocyanate composition solution corresponding to a solution state obtained by dissolving the polyisocyanate composition in a solvent has an NCO group mass content of 11.2 to 12.8%, where the total mass of the polyisocyanate composition solution is 100%.

8. 8. The polyisocyanate composition according to any one of claims 1 to 7, wherein the content of isophorone diisocyanate monomer is less than 0.5 wt%, preferably less than 0.35 wt%, more preferably less than 0.1 wt%.

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