Polyisocyanate composition

Abstract

Disclosed in the present disclosure is a polyisocyanate composition, which comprises an isocyanurate (methyl-substituted IPDI trimer) having a structure A and an isocyanurate (IPDI trimer) having a structure B. By means of limiting the molar ratio of the two isocyanurates, the solubility of the polyisocyanate composition in a non-polar solvent is enhanced, making it convenient for downstream customers to use the polyisocyanate composition.

Description

A polyisocyanate composition Technical Field

[0001] The embodiments of the present application relate to the technical field of polyisocyanates, for example, a polyisocyanate composition. Background Art

[0002] The technology of modifying isophorone diisocyanate (IPDI) monomers under the action of a catalyst is well known in the art. For example, a polymerization reaction or an alcohol modification reaction is performed, and after reaching the desired conversion rate, unreacted IPDI monomers are removed by vacuum distillation or thin film evaporation to obtain an IPDI-based polyisocyanate composition product. For reference, US2004176562A1, US6093817, CN107827832, etc.

[0003] The polyisocyanate composition prepared by IPDI polymerization has obvious fast-drying properties and has been widely used in the polyurethane coating industry. Moreover, since the polyisocyanate composition prepared by IPDI is mostly solid at room temperature, it is a common practice for customers in the industry to dissolve it in a solvent for use.

[0004] In the actual downstream application process, it was found that the IPDI-based polyisocyanate composition has poor solubility in non-polar solvents and the turbidity is easily increased, which in turn affects the use of downstream customers.

[0005] Summary of the Invention

[0006] 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.

[0007] During the actual research process, the researchers found that when the polyisocyanate composition contains the following methyl-substituted specific structure A, the solubility of the composition in non-polar solvents is increased.

[0008] In order to enhance the solubility of non-polar solvents, the technical solutions adopted in the embodiments of the present application are as follows:

[0009] A polyisocyanate composition comprising an isocyanurate of structure A and an isocyanurate of structure B:

[0010] The structure A is:

[0011] R'1, R'2, and R'3 are 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);

[0012] In the above structural formula, one, two or three of R1, R2, R3, R4, R5, R6 and R7 are CH3, and the rest are hydrogen.

[0013] Structure B is

[0014] Z1, Z2, and Z3 can be any one or both of the following two structures:

[0015] Meanwhile, the molar ratio of the isocyanurate of structure A to the isocyanurate of structure B is 0.0005-0.03.

[0016] In the polyisocyanate composition described herein, the molar ratio of the isocyanurate of structure A to the isocyanurate of structure B is 0.005-0.02.

[0017] The molar ratio of the isocyanurate of structure A to structure B, when above the lower limit, will enhance the solubility in non-polar solvents, which is beneficial to the paint film. When below the upper limit, the increase in the viscosity of the solution state will be suppressed, which is beneficial to downstream construction.

[0018] In the present application, structure B is an isophorone diisocyanate trimer, and structure A is a methyl-substituted isophorone diisocyanate trimer.

[0019] The method for controlling the molar ratio of the isocyanurate of structure A to 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 polymerizing isophorone diisocyanate or by adding structure A.

[0020] If the composition is prepared by the polymerization method of isophorone diisocyanate, the content 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.

[0021] Wherein, the structure of the methyl-substituted isophorone diisocyanate (methyl-substituted IPDI) is as follows:

[0022] Among them, R1, R2, R3, R4, R5, R6, and R7 have the same meanings as in Formula I and Formula II.

[0023] The content of the methyl-substituted isophorone diisocyanate can be adjusted during the preparation of isophorone diisocyanate to obtain an isophorone diisocyanate monomer containing the methyl-substituted isophorone diisocyanate, or it can be controlled by adding it before preparing the trimer.

[0024] The preparation process of IPDI involves preparing isophoronenitrile from isophorone and hydrogen cyanide, which then reacts with ammonia and hydrogen to form isophoronediamine, which is then phosgenated to yield IPDI. Research has revealed that methyl-substituted IPDI monomers may be produced during the IPDI preparation process. The content of these methyl-substituted products in IPDI can be controlled by manipulating the reaction and / or separation conditions, such as by adjusting the methylamine content in the ammonia feed, the chloride content in the hydrogenation catalyst, or the number and conditions of distillation. Methyl-substituted isophorone diisocyanate trimers (Structure A) can also be prepared separately, with the molar ratio of the two adjusted by addition.

[0025] The specific preparation method of IPDI containing methyl-substituted isophorone diisocyanate can be referred to CN115894857A.

[0026] In the present application, the mass content of the isocyanurate of structure B in the isophorone diisocyanate-based polyisocyanate composition is 50%-75%, preferably 50%-70%, more preferably 55-65%, and more preferably 59%-63%. This content can be determined by gel chromatography.

[0027] In the present application, the polyisocyanate composition based on isophorone diisocyanate has an isocyanate group (-NCO) content of 16 to 18% by weight, preferably 16.5 to 17.5%. On the one hand, the NCO group content in the composition should not be too low, as too low a content is not conducive to the structural crosslinking of the paint film. On the other hand, the NCO content should not be too high, as too high a content generally reduces the hardness of the paint film.

[0028] In the present application, the polyisocyanate composition based on isophorone diisocyanate may be in a solid state or in a solution state after being dissolved in a solvent;

[0029] Since the polyisocyanate composition described in the present application is in a solid state at room temperature, generally at 25°C, in some specific embodiments, the polyisocyanate composition based on isophorone diisocyanate described in the present application can also be dissolved in a solvent to obtain a polyisocyanate composition solution, which is in the state of a solution after being dissolved in a solvent.

[0030] In the polyisocyanate composition solution of the present application, the solvent is selected from any one or a combination of at least two of butyl acetate, ethyl acetate, solvent oil, toluene, xylene, propylene glycol methyl ether acetate, diheptanone, etc.;

[0031] Preferably, the mass proportion of the solvent is 28-32%, for example 29%, 30%, 31%, preferably 30%, based on the total mass of the polyisocyanate composition solution as 100%; if the solvent content in the composition solution is too high, the economic benefits of downstream applications will be reduced, while if the solvent content is too low, the viscosity of the solution will be too high, which is also not lower than that of downstream use.

[0032] Preferably, the polyisocyanate composition solution corresponding to the solution state after dissolving it with a solvent has an NCO group mass content of 11.2 to 12.8%, for example, 11.3%, 11.6%, 11.9%, 12.2%, 12.5%, 12.8%, preferably 12%, based on the total mass of the polyisocyanate composition solution as 100%.

[0033] In some specific embodiments, the polyisocyanate composition based on isophorone diisocyanate described in the present application, wherein the content of isophorone diisocyanate monomer is less than 0.5wt%, for example, 0.01wt%, 0.05wt%, 0.1wt%, 0.2wt%, 0.3wt%, 0.4wt%, preferably less than 0.35wt%, more preferably less than 0.1wt%, and the reduced content of IPDI monomer is beneficial to downstream construction safety.

[0034] The method of polymerizing isophorone diisocyanate is not limited, as long as the composition of the polyisocyanate composition can meet the aforementioned requirements of this application.

[0035] According to the method disclosed in the related art, for example, it can be prepared by the following method:

[0036] In the presence of a polymerization catalyst, isophorone diisocyanate undergoes a polymerization reaction, and the polymerization reaction is terminated when the mass content of NCO groups in the system reaches 20-30%, for example, 24%, 25%, 26%, or 27%. Unreacted monomers are then removed to obtain the isophorone diisocyanate-based polyisocyanate composition.

[0037] The basic method for the polymerization reaction of isocyanates is known in the relevant art. In a specific polymerization reaction process, isophorone diisocyanate can be 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., 50-110° C., for example, 70° C., 90° C.), and then the catalyst solution is added dropwise thereto. 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 elaborated here.

[0038] In some specific embodiments, the amount of the catalyst is 0.001-0.1% by mass of isophorone diisocyanate, for example, 0.005%, 0.01%, 0.02%, 0.04%, 0.06%, 0.08%, preferably 0.01-0.03%.

[0039] The polymerization catalyst used in the present application is selected from: (1) hydroxides of tetraalkylammonium (e.g., tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrabutylammonium hydroxide, benzyltrimethylammonium hydroxide, etc.), or organic acid salts of tetraalkylammonium (e.g., tetramethylammonium acetate, tetraethylammonium butyrate, etc.); (2) hydroxides of hydroxyalkylammonium (e.g., trimethylhydroxypropylammonium, trimethylhydroxyethylammonium, triethylhydroxypropylammonium, etc.) or organic acid salts thereof (e.g., acetic acid, butyric acid, isooctanoic acid, etc.); or, (3) metal (e.g., tin, zinc, etc.) salts of alkylcarboxylic acids (e.g., acetic acid, capric acid, octanoic acid, etc.); preferably one or more of (1) or (2).

[0040] In some specific embodiments, the catalyst used in the present application is dissolved in an organic solvent to prepare a catalyst solution, which is then added to the system to catalyze the polymerization reaction;

[0041] Specifically, in the catalyst solution, the mass concentration of the catalyst is 1 to 40%, such as 5%, 10%, 15%, 20%, 25%, 30%, 35%, preferably 10 to 30%.

[0042] Specifically, the organic solvent is selected from an alcohol solvent, preferably any one of a monool and a diol, or a combination of at least two thereof. In the present application, the monool can be selected from any one of 1-propanol, 2-propanol, n-butanol, isobutanol, sec-butanol, tert-butanol, n-octanol, isooctyl alcohol, heptanol, n-butanol, hexanol, heptanol or isooctyl alcohol, or a combination of at least two thereof; the diol can be selected from any one of diethylene glycol, 1,3-butanediol, 1,6-hexanediol, 1,4-butanediol, 2-ethyl-1,6-hexanediol, etc., or a combination of at least two thereof.

[0043] In some specific embodiments, when the polymerization reaction is carried out to an NCO value of 23 to 28%, for example, 24%, 25%, 26%, or 27%, a terminator can be used to terminate the reaction. 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, preferably 1.

[0044] The terminator is selected from any one or a combination of at least two of phosphate or benzenesulfonic acid terminators, for example, any one or a combination of at least two of dibutyl phosphate, diisooctyl phosphate or p-toluenesulfonic acid.

[0045] In some other embodiments, the above-mentioned polymerization reaction can also be terminated by heating and staying for a period of time. In the specific implementation process, the system can be heated to 120-130°C (for example, 122°C, 124°C, 126°C, 128°C) and stayed for 30-60 minutes (for example, 35 minutes, 40 minutes, 45 minutes, 50 minutes, 55 minutes).

[0046] In some specific embodiments, an optional technical solution is to control the mass content of methyl-substituted IPDI in the raw IPDI monomer to 0.01%-0.27%, obtain a reaction solution under the above-mentioned reaction conditions, and then remove unreacted isophorone diisocyanate monomer in the polymerization reaction system by thin film evaporation. In some specific embodiments, a thin film evaporator can be used to remove unreacted isophorone diisocyanate monomer in the reaction system at 170-200° C. and 10-200 PaA (e.g., 50 PaA, 100 PaA, 150 PaA) to obtain the polyisocyanate composition of the present application.

[0047] Another optional technical solution is to directly subject the enriched methyl-substituted IPDI to a polymerization reaction according to the above method to obtain a polyisocyanate composition rich in structure A. The polyisocyanate composition of the present application can also be obtained by blending the composition rich in structure A with the polyisocyanate composition rich in structure B.

[0048] The IPDI-based polyisocyanate composition described in this application can be used in the fields of automotive repair paint, automotive original paint, rail transit coating, etc.

[0049] Compared with the related art, the technical solution of the embodiment of the present application has the beneficial effect of increasing the solvent type of non-polar solvent while ensuring the appropriate viscosity of downstream construction, thereby facilitating the use of downstream customers.

[0050] Still other aspects will become apparent upon reading and understanding the detailed description. DETAILED DESCRIPTION

[0051] In order to better understand the present application, the content of the present application is further explained below with reference to the embodiments.

[0052] The sources of the main raw materials used in the following examples are as follows. Other raw materials are common commercially available unless otherwise specified:

[0053] The sources of the main raw materials in the following examples are as follows. Other raw materials are common commercially available unless otherwise specified:

[0054] Isophorone diisocyanate (IPDI): Wanhua Chemical;

[0055] n-Hexanol: Sigma-Aldrich, 98%;

[0056] Isooctyl alcohol: Sigma-Aldrich, 98%;

[0057] n-Butanol: Sigma-Aldrich, 99%;

[0058] 1,3-Butanediol: Sigma-Aldrich, 99%;

[0059] Trimethylhydroxypropyl ammonium ethylhexanoate: Sigma-Aldrich, 95%;

[0060] Benzyltrimethylammonium hydroxide: Sigma-Aldrich, 95%;

[0061] Tetrabutylammonium hydroxide: Sigma-Aldrich, 95%;

[0062] Tetrabutylammonium acetate: Sigma-Aldrich, 96%

[0063] Dibutyl phosphate, Sigma-Aldrich, 97%;

[0064] Dioctyl phosphate, Sigma-Aldrich, 96%;

[0065] p-Toluenesulfonic acid, Sigma-Aldrich, 95%;

[0066] Butyl acetate: Sinopharm Reagent, 99%

[0067] Solvent oil S100: Huafeng spandex industrial product.

[0068] The main testing methods used in each embodiment of this application are as follows:

[0069] 1. Test method for monomer content in polyisocyanate composition: GB / T 18446-2009.

[0070] 2. Determination 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 was performed using 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:

[0071] Where: V—the amount of hydrochloric acid standard solution used when titrating the sample, ml;

[0072] V0—the amount of hydrochloric acid standard solution used in blank titration, ml;

[0073] c—actual concentration of hydrochloric acid standard solution, mol / L;

[0074] 0.04202—the mass of isocyanate in grams equivalent to 1.00 ml of standard hydrochloric acid solution [c(HCl) = 1.000 mol / L];

[0075] m—total mass of sample, g.

[0076] 3. Test method for the content of methyl-substituted IPDI in IPDI monomer

[0077] The content of methylated isophorone diisocyanate in the isophorone diisocyanate composition described in the present application can be analyzed by gas chromatography: the sample is dissolved in a solvent (preferably dichloromethane) and then analyzed by gas chromatography, detected by a hydrogen ion flame detector (FID), and quantitatively calculated by area normalization.

[0078] The chromatographic conditions are as follows:

[0079] Carrier gas: purified and dried high-purity nitrogen (purity ≥ 99.999%);

[0080] Combustion gas: hydrogen (purity ≥ 99.999%), flow rate 40 mL / min;

[0081] Combustion-supporting gas: purified and dry air, with a flow rate of 400 mL / min;

[0082] Makeup gas: nitrogen, flow rate 30mL / min;

[0083] Column flow rate: 1.06 mL / min;

[0084] Split ratio: 30:1;

[0085] Column temperature (programmed temperature): 140°C for 0 min, increase the temperature to 220°C at 10°C / min, hold for 1 min, increase the temperature to 260°C at 5°C / min, hold for 0 min, increase the temperature to 280°C at 10°C / min, hold for 1 min;

[0086] Inlet temperature: 270°C;

[0087] Detector temperature: 290°C;

[0088] Injection volume: 0.2 μL.

[0089] 4. Molar ratio of structure A to structure B:

[0090] The abundance ratio of the isocyanurate structure formed by polymerization of methyl-substituted IPDI to the isocyanurate trimer formed by polymerization of three IPDIs (referred to as compound α) in the polyisocyanate composition was determined by the following method.

[0091] Specifically, the terminal isocyanate groups of the polyisocyanate composition of the present patent application were urethanized with methanol and analyzed using a liquid chromatography-mass spectrometer (LC / MS). The sample preparation method and measurement method are described below.

[0092] ①Sample preparation method

[0093] 100 mg of the polyisocyanate composition was weighed, and methanol was added to a concentration of 10 mg / mL. The mixture was then left to stand for 2 days to allow the existing isocyanate groups to react completely with methanol, thereby preparing a methanol solution.

[0094] ②Determination method

[0095] The methanol solution obtained above was measured using the following apparatus.

[0096] ·LC

[0097] Device: Waters ACQUITY UPLC

[0098] Column: Phenomenex, Kinetex 2.6μXB-C18 100A (inner diameter 2.1 mm, length 50 mm)

[0099] Column temperature: 40°C

[0100] Detection: 220nm

[0101] Flow rate: 0.3 mL / min

[0102] Mobile phase: gradient of A and B solutions: A = water (0.05% formic acid), B = acetonitrile (0.05% formic acid)

[0103] Injection volume: 1 μL

[0104] ·MS

[0105] Device: Waters, Synapt G2

[0106] Ionization: ESI

[0107] Mode: Positive

[0108] Scan range: m / z 250-2000

[0109] The methanol adduct of isocyanurate trimer (compound β) formed by the polymerization of three IPDIs was detected by the detection ion (m / z) 762.

[0110] For the isocyanurate structures formed by the polymerization of methyl-substituted IPDI, the different numbers of methyl substitutions lead to different ion (m / z) positions.

[0111] For the isocyanurate structures polymerized with 1, 2, or 3 methyl-substituted IPDI, the ion peak positions (m / z) are 776, 790, and 804, which are defined as compounds a, b, and c;

[0112] The ion peak positions (m / z) of the isocyanurate structures formed by the polymerization of 4, 5, or 6 methyl-substituted IPDI are 818, 832, and 846, which are defined as compounds d, e, and f;

[0113] The ion peak positions (m / z) of the isocyanurate structure formed by the polymerization of 7, 8, or 9 methyl-substituted IPDI are 860, 874, and 888, which are defined as compounds g, h, and i.

[0114] The ratio of the peak area of ​​compounds a to i to the peak area of ​​compound β was calculated as the molar ratio of structure A to structure B.

[0115] 5. Evaluation method of solubility in non-polar solvents

[0116] The polyisocyanate composition and solvent oil S100 were mixed in a mass ratio of 1:1 to obtain a dilution, which was then tested using a turbidimeter HACH 2100:

[0117] A turbidity of no more than 0.3 indicates excellent solubility;

[0118] Turbidity is greater than 0.3 and not higher than 0.6, and the solubility is good;

[0119] The turbidity is greater than 0.6 and not higher than 0.9, and the solubility is acceptable;

[0120] Turbidity greater than 0.9 indicates poor solubility.

[0121] 6. Evaluation method of polar solvent viscosity

[0122] The polyisocyanate composition and butyl acetate were mixed in a mass ratio of 7:3 to obtain a solution product, and the viscosity at 25°C was tested using a Broolfield DV2T viscometer:

[0123] The viscosity at 25°C is not higher than 600 cP, which is excellent for downstream construction.

[0124] Viscosity at 25°C, not higher than 800 cP, good for downstream construction;

[0125] Viscosity at 25°C, not higher than 1000 cP, for downstream construction: medium;

[0126] Viscosity at 25°C, greater than 1000 cP, for downstream application: poor.

[0127] 7. Test method for solid content:

[0128] Weigh an accurate amount of the composition solution sample (about 0.5 g) and place it in an aluminum foil dish (accurately weigh the mass), place it in a 120°C oven for 2 hours, take it out and cool it down before weighing it;

[0129] Solid content = (weight after drying - weight of aluminum foil dish) / sample weight * 100%.

[0130] Example 1

[0131] Preparation of catalyst solution: Tetrabutylammonium hydroxide was dissolved in n-butanol to prepare a solution with a concentration of 20 wt%.

[0132] 1000 g of IPDI (methyl-substituted IPDI content of 0.01% by mass) was placed in a round-bottom flask equipped with a reflux condenser, a stirrer, a thermometer, and a nitrogen inlet; the reaction system was heated to 70° C., and the catalyst solution prepared above (the catalyst amount was 0.015% by mass of the IPDI) was then added dropwise to the reaction system with stirring. The polymerization reaction was carried out by controlling the reaction temperature to be between 70 and 80° C. When the NCO content of the reaction solution was 28% by mass, dibutyl phosphate was added in an amount equimolar to the catalyst to terminate the reaction;

[0133] Unreacted isophorone diisocyanate monomer was evaporated from the polymerization reaction solution using a thin film evaporator at a temperature of 185° C. and an absolute pressure of 50 Pa. The mixture was allowed to stand for 10 minutes to a concentration of 0.34 wt %. IPDI trimer (i.e., isocyanate of structure B) having a mass content of 68% was dissolved in butyl acetate to obtain a solution product having a solid content of 70 wt %, thereby obtaining a polyisocyanate composition solution 1.

[0134] Example 2

[0135] Preparation of catalyst solution: dissolve trimethylhydroxypropyl ammonium isooctanoate in isooctyl alcohol to prepare a solution with a concentration of 30 wt%.

[0136] 1000 g of IPDI (methyl-substituted IPDI mass content 0.08%) was placed in a round-bottom flask equipped with a reflux condenser, a stirrer, a thermometer, and a nitrogen inlet; the reaction system was heated to 80° C., and then the catalyst solution prepared above (catalyst level was 0.016% of the IPDI mass) was added dropwise to the reaction system under stirring. The reaction temperature was controlled to carry out the polymerization reaction at 80 to 90° C., and when the NCO mass content of the reaction solution was 25%, diisooctyl phosphate in an equimolar amount with the catalyst was added to terminate the reaction;

[0137] Unreacted isophorone diisocyanate monomer was evaporated from the polymerization reaction solution using a thin film evaporator at a temperature of 185° C. and an absolute pressure of 50 Pa. The mixture was allowed to stand for 15 minutes to a concentration of 0.32 wt %. The mass content of IPDI trimer (i.e., isocyanate of structure B) was 62%, which was then dissolved in butyl acetate to obtain a solution product having a solid content of 70 wt %, thereby obtaining polyisocyanate composition solution 2.

[0138] Example 3

[0139] Preparation of catalyst solution: dissolve benzyltrimethylammonium hydroxide in n-hexanol to prepare a solution with a concentration of 1 wt%.

[0140] 1000g of IPDI (methyl-substituted IPDI mass content 0.18%) was placed in a round-bottomed flask equipped with a reflux condenser, a stirrer, a thermometer, and a nitrogen inlet; the reaction system was heated to 60°C, and then the catalyst solution (catalyst level was 0.015% of the IPDI mass) prepared above was added dropwise to the reaction system under stirring. The reaction temperature was controlled to carry out the polymerization reaction at 60-70°C. When the NCO mass content of the reaction solution was 25%, diethyl phosphate (DOP) was added in a catalyst molar ratio of 1.1 to terminate the reaction.

[0141] Unreacted isophorone diisocyanate monomer was evaporated from the polymerization reaction solution using a thin film evaporator at 200° C. and an absolute pressure of 100 Pa. The mixture was allowed to stand for 10 minutes, resulting in a content of 0.33 wt %. The mass content of IPDI trimer (i.e., isocyanate of structure B) was 62%, which was then dissolved in butyl acetate to obtain a solution product with a solid content of 70 wt %, yielding polyisocyanate composition solution 3.

[0142] Example 4

[0143] Preparation of catalyst solution: Tetrabutylammonium acetate was dissolved in 1,3-butanediol to prepare a solution with a concentration of 10 wt%.

[0144] 1000 g of IPDI (methyl-substituted IPDI content of 0.35%) was placed in a round-bottom flask equipped with a reflux condenser, a stirrer, a thermometer, and a nitrogen inlet; the reaction system was heated to 70° C., and the catalyst solution prepared above (catalyst content of 0.0155% by mass of IPDI) was then added dropwise to the reaction system under stirring. The reaction temperature was controlled to be between 70 and 80° C. to carry out the polymerization reaction. When the NCO content of the reaction solution was 23%, p-toluenesulfonic acid in an equimolar amount to the catalyst was added to terminate the reaction;

[0145] Unreacted isophorone diisocyanate monomer was evaporated from the polymerization reaction solution using a thin film evaporator at a temperature of 200° C. and an absolute pressure of 100 Pa. The mixture was allowed to stand for 10 min, resulting in a content of 0.3 wt %. The mass content of IPDI trimer (i.e., isocyanate of structure B) was 58%, which was then dissolved in solvent oil S100 to obtain a solution product with a solid content of 70 wt %, yielding a polyisocyanate composition solution 4.

[0146] Example 5

[0147] Preparation of catalyst solution: dissolve benzyltrimethylammonium hydroxide in isooctyl alcohol to prepare a solution with a concentration of 5 wt%.

[0148] 1000 g of IPDI (methyl-substituted IPDI content of 0.55% by mass) was placed in a round-bottom flask equipped with a reflux condenser, a stirrer, a thermometer, and a nitrogen inlet; the reaction system was heated to 90° C., and then the prepared catalyst solution (catalyst amount of 0.016% by mass of IPDI) was added dropwise to the reaction system with stirring. The reaction temperature was controlled between 100 and 110° C. to carry out a polymerization reaction. When the NCO mass content of the reaction solution system was 26%, the system was heated to 130° C. (heating rate of 1° C. / min) and the temperature was maintained for 30 min after the heating was completed to obtain a polymerization reaction solution.

[0149] Unreacted isophorone diisocyanate monomer was evaporated from the polymerization reaction solution using a thin film evaporator at 190° C. and an absolute pressure of 50 Pa, and the mixture was allowed to stand for 10 minutes to a concentration of 0.3 wt %. The mass content of IPDI trimer (i.e., isocyanate of structure B) was 64%, which was then dissolved in butyl acetate to obtain a solution product with a solid content of 70 wt %, yielding a polyisocyanate composition solution 5.

[0150] Comparative Example 1

[0151] Preparation of catalyst solution: same as Example 3

[0152] 1000 g of IPDI (methyl-substituted IPDI content: 0.002%) was placed in a round-bottom flask equipped with a reflux condenser, a stirrer, a thermometer, and a nitrogen inlet; the reaction system was heated to 70° C., and then the above-prepared catalyst solution (catalyst amount: 0.015% by mass of IPDI) was added dropwise to the reaction system with stirring, and the reaction temperature was controlled between 100 and 110° C. to carry out a polymerization reaction. When the NCO content of the reaction solution was 26%, dibutyl phosphate in an amount equimolar to tetrabutylammonium difluoride was added to terminate the reaction to obtain a polymerization reaction solution;

[0153] Unreacted isophorone diisocyanate monomer was removed from the polymerization reaction solution by evaporation using a thin film evaporator at a temperature of 200° C. and an absolute pressure of 100 Pa to a content of 0.33 wt %. The mass content of IPDI trimer (i.e., isocyanate of structure B) was 64%, and the product was dissolved in butyl acetate to obtain a solution product with a solid content of 70%, thereby obtaining a polyisocyanate composition 3-1.

[0154] Comparative Example 2

[0155] Preparation of catalyst solution: same as Example 3

[0156] 1000 g of IPDI (methyl-substituted IPDI content of 0.60% by mass) was placed in a round-bottom flask equipped with a reflux condenser, a stirrer, a thermometer, and a nitrogen inlet; the reaction system was heated to 70° C., and then the prepared catalyst solution (catalyst amount of 0.015% by mass of IPDI) was added dropwise to the reaction system with stirring. The reaction temperature was controlled between 70° C. and 80° C. to carry out a polymerization reaction. When the NCO content of the reaction solution reached 25% by mass, dibutyl phosphate in an amount equimolar to tetrabutylammonium difluoride was added to terminate the reaction to obtain a polymerization reaction solution.

[0157] Unreacted isophorone diisocyanate monomer was evaporated from the polymerization reaction solution using a thin film evaporator at 200° C. and an absolute pressure of 100 Pa to a content of 0.33 wt %. The mass content of IPDI trimer (i.e., isocyanate of structure B) was 62%, and the product was dissolved in butyl acetate to obtain a solution product with a solid content of 70%, thereby obtaining a polyisocyanate composition 3-2.

[0158] 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.

[0159] Table 1 Polyisocyanate composition composition and storage stability test results

[0160] The above results indicate that by controlling the molar ratio of structure A / structure B isocyanurates, it is possible to enhance the solubility in non-polar solvents while avoiding an increase in downstream application viscosity.

[0161] Although the present application has been described in detail in the foregoing for purposes of illustration, these are for illustrative purposes only and variations may be made therein by those skilled in the art without departing from the spirit and scope of the present application, the scope of which is defined by the claims.

Claims

1. A polyisocyanate composition comprising an isocyanurate of structure A and an isocyanurate of structure B: The structure A is: R'1, R'2, and R'3 are selected from the following four structures, respectively, wherein at least one of R'1, R'2, and R'3 is selected from structure (I) or structure (II): In the above structural formula, one, two or three of R1, R2, R3, R4, R5, R6 and R7 are CH3, and the rest are hydrogen; Structure B is Z1, Z2, and Z3 can be any one or both of the following two structures: The molar ratio of the isocyanurate of structure A to the isocyanurate of structure B is 0.0005-0.

03.

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

02.

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

4. The polyisocyanate composition according to any one of claims 1 to 3, 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 is dissolved in a solvent to obtain a polyisocyanate composition solution, and the solvent is selected from any one of butyl acetate, ethyl acetate, solvent oil, toluene, xylene, propylene glycol methyl ether acetate, diheptanone, etc., or a combination of at least two thereof.

6. The polyisocyanate composition according to claim 5, wherein The mass proportion of the solvent is 28-32%, based on the total mass of the polyisocyanate composition solution being 100%.

7. The polyisocyanate composition according to claim 5 or 6, wherein The polyisocyanate composition solution corresponding to the solution state after the polyisocyanate is dissolved in a solvent has an NCO group content of 11.2-12.8% by weight based on the total weight of the polyisocyanate composition solution being 100%.

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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