Polyisocyanate composition

Abstract

The invention discloses a polyisocyanate composition, which comprises isocyanurate (methyl-substituted IPDI tripolymer) of a structure A and isocyanurate (IPDI tripolymer) of a structure B. By limiting the molar ratio of the two isocyanurate, the solubility of a non-polar solvent is enhanced, and the polyisocyanate composition is beneficial to downstream customers.

Description

Technical Field

[0001] The invention belongs to the technical field of polyisocyanates, and in particular relates to a polyisocyanate composition. Background Art

[0002] The technology of modifying isophorone diisocyanate IPDI monomer under the action of a catalyst is well known in the art, such as performing a polymerization reaction or an alcohol modification reaction, and removing unreacted IPDI monomer by vacuum distillation or thin film evaporation after reaching the expected conversion rate, thereby obtaining a polyisocyanate composition product based on IPDI, and reference can be made to patents US2004176562A1, US6093817, CN107827832, etc.

[0003] The polyisocyanate composition prepared by IPDI polymerization has obvious quick-drying characteristics 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. Summary of the invention

[0005] In 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 a non-polar solvent is increased.

[0006] In order to enhance the solubility of non-polar solvents, the technical solution adopted by the present invention is as follows:

[0007] A polyisocyanate composition, comprising an isocyanurate of structure A and an isocyanurate of structure B:

[0008] The structure A is:

[0009]

[0010] 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);

[0011]

[0012]

[0013] Among R1, R2, R3, R4, R5, R6, and R7 in the above structural formula, one, two, or three groups are CH3, and the rest are hydrogen.

[0014] Structure B is

[0015] Z1, Z2, and Z3 can be any one or both of the following two structures:

[0016]

[0017] Meanwhile, the molar ratio of the isocyanurate of the structure A to the isocyanurate of the structure B is 0.0005-0.03.

[0018] In the polyisocyanate composition of the present invention, the molar ratio of the isocyanurate of structure A to the isocyanurate of structure B is 0.005-0.02.

[0019] The molar ratio of the isocyanurate of structure A to structure B, when being above the lower limit, will enhance the solubility in the non-polar solvent, which is beneficial to the paint film, and when being below the upper limit, will inhibit the increase of the viscosity in the solution state, which is beneficial to the downstream construction.

[0020] In the present invention, structure B is an isophorone diisocyanate trimer, and structure A is a methyl-substituted isophorone diisocyanate trimer.

[0021] 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 invention can be directly obtained by the polymerization method of isophorone diisocyanate or the molar ratio of the present invention can be achieved by adding structure A.

[0022] If the composition is prepared by the method of isophorone diisocyanate polymerization, 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.

[0023] Wherein, the structure of the methyl-substituted isophorone diisocyanate (methyl-substituted IPDI) is as follows:

[0024]

[0025] Among them, R1, R2, R3, R4, R5, R6, and R7 have the same meanings as in Formula I and Formula II.

[0026] 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 can be controlled by adding it before preparing the trimer.

[0027] Preparation process of IPDI: isophorone nitrile is prepared from isophorone and hydrogen cyanide, which is further reacted with ammonia and hydrogen to form isophorone diamine, and then IPDI is obtained through phosgenation. Studies have shown that methyl-substituted IPDI monomers may be produced during the preparation of IPDI. The content of methyl-substituted products in IPDI can be controlled by controlling the reaction conditions and / or separation conditions, such as controlling the methylamine content in the raw ammonia, or the chloride content in the hydrogenation catalyst, or the number of distillation times, distillation conditions, etc. Methyl-substituted isophorone diisocyanate trimer (structure A) can also be prepared separately, and the molar ratio of the two can be adjusted by adding.

[0028] The specific preparation method of IPDI containing methyl-substituted isophorone diisocyanate can refer to patent CN115894857A.

[0029] In the present invention, the mass content of the isocyanurate of structure B in the polyisocyanate composition based on isophorone diisocyanate is 50%-75%, preferably 50%-70%, more preferably 55-65%, more preferably 59%-63%, and this content can be determined by gel chromatography.

[0030] In the present invention, the polyisocyanate composition based on isophorone diisocyanate has an isocyanate group (-NCO) mass content of 16 to 18%, preferably 16.5 to 17.5%. On the one hand, the NCO group content in the composition should not be too low, which is not conducive to the structural crosslinking of the paint film. On the other hand, the NCO content should not be too high, which usually reduces the hardness of the paint film.

[0031] In the present invention, the polyisocyanate composition based on isophorone diisocyanate may be in a solid state or in a solution state after being dissolved in a solvent;

[0032] Since the polyisocyanate composition of the present invention is in a solid state at room temperature, generally at 25°C, in some specific embodiments, the polyisocyanate composition based on isophorone diisocyanate of the present invention can also be dissolved in a solvent to obtain a polyisocyanate composition solution, which is in a solution state after being dissolved in a solvent.

[0033] In the polyisocyanate composition solution of the present invention, 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.;

[0034] 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 solution viscosity will be too high, which is also not lower than that of downstream use.

[0035] Preferably, the polyisocyanate composition solution corresponding to the solution state after dissolving it with a solvent has an NCO group mass content of 11.2-12.8%, 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%.

[0036] In some specific embodiments, the polyisocyanate composition based on isophorone diisocyanate of the present invention, 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%, the reduced content of IPDI monomer is beneficial to downstream construction safety.

[0037] The method for polymerizing isophorone diisocyanate is not limited, as long as the composition of the polyisocyanate composition can meet the aforementioned requirements of the present invention.

[0038] According to the method disclosed in the prior art, for example, it can be prepared by the following method:

[0039] 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 is 20-30%, for example, 24%, 25%, 26%, or 27%, and then unreacted monomers are removed to obtain the isophorone diisocyanate-based polyisocyanate composition.

[0040] The basic method for the polymerization reaction of isocyanate is known in the prior art. In the 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, and then the system is heated to a predetermined reaction temperature range (such as 50 to 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 repeated here.

[0041] 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%.

[0042] The polymerization catalyst used in the present invention 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, caprylic acid, etc.); preferably one or more of (1) or (2).

[0043] In some specific embodiments, the catalyst used in the present invention is dissolved in an organic solvent to prepare a catalyst solution, which is then added to the system to catalyze the polymerization reaction;

[0044] Specifically, in the catalyst solution, the mass concentration of the catalyst is 1-40%, for example, 5%, 10%, 15%, 20%, 25%, 30%, 35%, preferably 10-30%.

[0045] Specifically, the organic solvent is selected from alcohol solvents, preferably any one of monoalcohols and diols or a combination of at least two thereof. In the present invention, the monoalcohol 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.

[0046] In some specific embodiments, when the above polymerization reaction is carried out to the NCO value in the system of 23-28%, such as 24%, 25%, 26%, 27%, a terminator can be used to terminate the reaction. Specifically, the molar ratio of the terminator to the polymerization catalyst is 1-1.1, such as 1.02, 1.04, 1.06, 1.08, preferably 1;

[0047] 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.

[0048] 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 30-60min (for example, 35min, 40min, 45min, 50min, 55min).

[0049] 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%-0.27%, obtain a reaction solution under the above reaction conditions, and then remove the 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 the unreacted isophorone diisocyanate monomer in the reaction system under the conditions of 170-200° C. and 10-200 PaA (for example, 50 PaA, 100 PaA, 150 PaA) to obtain the polyisocyanate composition of the present invention.

[0050] 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 invention can also be obtained by blending the composition rich in structure A with the polyisocyanate composition rich in structure B.

[0051] The IPDI-based polyisocyanate composition of the present invention can be used in the fields of automobile repair paint, automobile original paint, rail transportation paint, etc.

[0052] Compared with the prior art, the technical solution of the present invention has the beneficial effect of increasing the solvent type of non-polar solvent while ensuring the appropriate downstream construction viscosity, thereby facilitating the use of downstream customers. DETAILED DESCRIPTION

[0053] In order to better understand the present invention, the content of the present invention is further explained below in conjunction with embodiments.

[0054] 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:

[0055] The sources of the main raw materials in the following examples are as follows. Other raw materials are common commercially available unless otherwise specified:

[0056] Isophorone diisocyanate (IPDI): Wanhua Chemical;

[0057] n-Hexanol: Sigma-Aldrich, 98%;

[0058] Isooctyl alcohol: Sigma-Aldrich, 98%;

[0059] n-Butanol: Sigma-Aldrich, 99%;

[0060] 1,3-Butanediol: Sigma-Aldrich, 99%;

[0061] Trimethylhydroxypropyl ammonium isooctanoate: Sigma-Aldrich, 95%;

[0062] Benzyltrimethylammonium hydroxide: Sigma-Aldrich, 95%;

[0063] Tetrabutylammonium hydroxide: Sigma-Aldrich, 95%;

[0064] Tetrabutylammonium acetate: sigma-Aldrich, 96%

[0065] Dibutyl phosphate, Sigma-Aldrich, 97%;

[0066] Di(2-ethylhexyl) phosphate, Sigma-Aldrich, 96%;

[0067] p-Toluenesulfonic acid, Sigma-Aldrich, 95%;

[0068] Butyl acetate: Sinopharm reagent, 99%

[0069] Solvent oil S100: Huafeng spandex industrial product.

[0070] The main testing methods used in each embodiment of the present invention are as follows:

[0071] 1. Test method for the content of monomers in polyisocyanate compositions: GB / T 18446-2009.

[0072] 2. Determination of NCO group content: After the isocyanate groups in the test sample are neutralized with an excess of 2 mol / L di-n-butylamine, the NCO group content based on the total mass of the sample is obtained by back titration with 1 mol / L hydrochloric acid. The calculation formula is as follows:

[0073]

[0074] Where: V—the amount of hydrochloric acid standard solution used when titrating the sample, ml;

[0075] V0—the amount of hydrochloric acid standard solution used in blank titration, ml;

[0076] c—actual concentration of hydrochloric acid standard solution, mol / L;

[0077] 0.04202—the mass of isocyanate in grams equivalent to 1.00 ml of standard hydrochloric acid solution [c(HCl)=1.000 mol / L];

[0078] m—total mass of sample, g.

[0079] 3. Test method for the content of methyl-substituted IPDI in IPDI monomer

[0080] The content of methylated isophorone diisocyanate in the isophorone diisocyanate composition of the present invention 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 method.

[0081] The chromatographic conditions were as follows:

[0082] Carrier gas: purified and dried high-purity nitrogen (purity ≥ 99.999%);

[0083] Combustion gas: hydrogen (purity ≥ 99.999%), flow rate 40mL / min;

[0084] Combustion-supporting gas: purified and dried air, with a flow rate of 400 mL / min;

[0085] Tail gas: nitrogen, flow rate 30mL / min;

[0086] Column flow rate: 1.06 mL / min;

[0087] Split ratio: 30:1;

[0088] Column temperature (programmed temperature rise): 140°C for 0 min, increase the temperature to 220°C at 10°C / min, maintain for 1 min, increase the temperature to 260°C at 5°C / min, maintain for 0 min, increase the temperature to 280°C at 10°C / min, maintain for 1 min;

[0089] Inlet temperature: 270°C;

[0090] Detector temperature: 290°C;

[0091] Injection volume: 0.2 μL.

[0092] 4. Molar ratio of structure A to structure B:

[0093] 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.

[0094] Specifically, the terminal isocyanate groups of the polyisocyanate composition of the present invention were urethanized with methanol and analyzed using a liquid chromatography-mass spectrometer (LC / MS). The sample preparation method and measurement method are described below.

[0095] ①Sample preparation method

[0096] 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.

[0097] ② Determination method

[0098] The methanol solution obtained above was measured using the following apparatus.

[0099] ·LC

[0100] Device: Waters ACQUITY UPLC

[0101] Column: Phenomenex, Kinetex 2.6μXB-C18 100A (inner diameter 2.1 mm, length 50 mm) Column temperature: 40°C

[0102] Detection: 220nm

[0103] Flow rate: 0.3 mL / min Mobile phase: Gradient of A and B solutions A = water (0.05% formic acid), B = acetonitrile (0.05% formic acid)

[0104] Injection volume: 1μL

[0105] ·MS

[0106] Device: Waters, Synapt G2

[0107] Ionization: ESI

[0108] Mode: Positive

[0109] Scan range: m / z 250~2000

[0110] The methanol adduct of isocyanurate trimer (compound β) formed by polymerization of three IPDIs was detected by the detection ion (m / z) 762.

[0111] For the isocyanurate structure formed by the polymerization of methyl-substituted IPDI, the different numbers of methyl substitutions lead to different ion (m / z) positions.

[0112] The ion peak positions (m / z) of the isocyanurate structures formed by the polymerization of 1, 2, or 3 methyl-substituted IPDI are 776, 790, and 804, which are defined as compounds a, b, and c;

[0113] 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;

[0114] The ion peak positions (m / z) of the isocyanurate structure formed by the polymerization of IPDI with 7, 8 or 9 methyl groups are 860, 874 and 888, and compounds g, h and i are defined.

[0115] 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.

[0116] 5. Evaluation method of solubility in non-polar solvents

[0117] The polyisocyanate composition and solvent oil S100 were mixed in a mass ratio of 1:1 to obtain a diluent, and then tested using a turbidity meter HACH 2100:

[0118] A turbidity of no higher than 0.3 indicates excellent solubility;

[0119] Turbidity is greater than 0.3 and not higher than 0.6, and the solubility is good;

[0120] The turbidity is greater than 0.6 and not higher than 0.9, and the solubility is acceptable;

[0121] Turbidity greater than 0.9 indicates poor solubility.

[0122] 6. Evaluation method of polar solvent dissolution viscosity

[0123] The polyisocyanate composition and butyl acetate were mixed in a mass ratio of 7:3 to obtain a solution product, and a viscosity test at 25°C was performed using a Broolfield DV2T viscometer:

[0124] The viscosity at 25℃ is not higher than 600cP, which is excellent for downstream construction;

[0125] Viscosity at 25°C, not higher than 800cP, for downstream construction: good;

[0126] Viscosity at 25°C, not higher than 1000cP, for downstream construction: medium;

[0127] Viscosity at 25°C, greater than 1000 cP, for downstream application: poor.

[0128] 7. Test method for solid content:

[0129] 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 weigh it after cooling;

[0130] Solid content = (weight after drying - weight of aluminum foil dish) / sample weight * 100%.

[0131] Example 1

[0132] Preparation of catalyst solution: Tetrabutylammonium hydroxide was dissolved in n-butanol to prepare a solution with a concentration of 20 wt%.

[0133] 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 then the catalyst solution prepared above (the catalyst amount was 0.015% of the mass of IPDI) was added dropwise to the reaction system under stirring, and the reaction temperature was controlled to be between 70 and 80° C. for polymerization reaction. When the NCO mass content of the reaction solution system was 28%, dibutyl phosphate in an amount equimolar to the catalyst was added to terminate the reaction;

[0134] The unreacted isophorone diisocyanate monomer in the polymerization reaction liquid was evaporated and removed using a thin film evaporator at a temperature of 185° C. and an absolute pressure of 50 Pa. The mixture was left for 10 min to make its content 0.34 wt %. The IPDI trimer (i.e., isocyanate of structure B) with a mass content of 68% was dissolved in butyl acetate to obtain a solution product with a solid content of 70 wt %, and a polyisocyanate composition solution 1 was obtained.

[0135] Example 2

[0136] Preparation of catalyst solution: Dissolve trimethylhydroxypropylammonium isooctanoate in isooctyl alcohol to prepare a solution with a concentration of 30 wt%.

[0137] 1000g of IPDI (methyl-substituted IPDI content of 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 (the catalyst amount was 0.016% of the mass of IPDI) was added dropwise to the reaction system under stirring, and the reaction temperature was controlled to be between 80 and 90°C for polymerization reaction. When the NCO mass content of the reaction solution system was 25%, diisooctyl phosphate in an amount equimolar to the catalyst was added to terminate the reaction;

[0138] The unreacted isophorone diisocyanate monomer in the polymerization reaction liquid was evaporated and removed using a thin film evaporator at a temperature of 185° C. and an absolute pressure of 50 Pa. The mixture was left for 15 minutes to make its content 0.32wt%. The mass content of IPDI trimer (i.e., isocyanate of structure B) was 62%, which was dissolved in butyl acetate to obtain a solution product with a solid content of 70wt%, and a polyisocyanate composition solution 2 was obtained.

[0139] Example 3

[0140] Preparation of catalyst solution: Dissolve benzyltrimethylammonium hydroxide in n-hexanol to prepare a solution with a concentration of 1 wt%.

[0141] 1000g of IPDI (methyl-substituted IPDI content of 0.18%) 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 60°C, and then the catalyst solution prepared above (the catalyst amount was 0.015% of the IPDI mass) was added dropwise to the reaction system under stirring, and the reaction temperature was controlled to be between 60 and 70°C for polymerization reaction. When the NCO mass content of the reaction solution system was 25%, diisooctyl phosphate was added in a molar ratio of 1.1 to the catalyst to terminate the reaction;

[0142] The unreacted isophorone diisocyanate monomer in the polymerization reaction liquid was evaporated and removed using a thin film evaporator at a temperature of 200° C. and an absolute pressure of 100 Pa. The mixture was left for 10 minutes to make its content 0.33wt%. The mass content of IPDI trimer (i.e., isocyanate of structure B) was 62%, which was dissolved in butyl acetate to obtain a solution product with a solid content of 70wt%, obtaining a polyisocyanate composition solution 3.

[0143] Example 4

[0144] Preparation of catalyst solution: Tetrabutylammonium acetate was dissolved in 1,3-butanediol to prepare a solution with a concentration of 10 wt%.

[0145] 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 then the catalyst solution prepared above (the catalyst amount was 0.0155% of the mass of IPDI) was added dropwise to the reaction system under stirring, and the reaction temperature was controlled to be between 70 and 80° C. to carry out polymerization reaction. When the NCO mass content of the reaction solution system was 23%, p-toluenesulfonic acid in an equimolar amount to the catalyst was added to terminate the reaction;

[0146] The unreacted isophorone diisocyanate monomer in the polymerization reaction liquid was evaporated and removed using a thin film evaporator at a temperature of 200°C and an absolute pressure of 100 Pa. The mixture was left for 10 minutes to make its content 0.3wt%. The mass content of IPDI trimer (i.e., isocyanate of structure B) was 58%, which was dissolved in solvent oil S100 to obtain a solution product with a solid content of 70wt%, and a polyisocyanate composition solution 4 was obtained.

[0147] Example 5

[0148] Preparation of catalyst solution: dissolve benzyltrimethylammonium hydroxide in isooctyl alcohol to prepare a solution with a concentration of 5 wt%.

[0149] 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 catalyst solution prepared above (the catalyst amount was 0.016% of the mass of IPDI) was added dropwise to the reaction system under stirring, and the reaction temperature was controlled between 100 and 110° C. to carry out polymerization reaction. When the NCO mass content of the reaction liquid system was 26%, the system was heated to 130° C. (heating rate of 1° C. / min), and the polymerization reaction liquid was obtained after the heating was completed and the temperature was kept for 30 min.

[0150] The unreacted isophorone diisocyanate monomer in the polymerization reaction liquid was evaporated and removed using a thin film evaporator at a temperature of 190° C. and an absolute pressure of 50 Pa, and the mixture was left there for 10 minutes to make its content 0.3wt%. The mass content of IPDI trimer (i.e., isocyanate of structure B) was 64%, which was dissolved in butyl acetate to obtain a solution product with a solid content of 70wt%, to obtain a polyisocyanate composition solution 5.

[0151] Comparative Example 1

[0152] Preparation of catalyst solution: Same as Example 3

[0153] 1000 g of IPDI (methyl-substituted IPDI mass 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 catalyst solution prepared above (the catalyst amount was 0.015% of the mass of IPDI) was added dropwise to the reaction system under stirring, and the reaction temperature was controlled between 100 and 110° C. to carry out polymerization reaction. When the NCO mass content of the reaction solution system was 26%, dibutyl phosphate in an amount equimolar to tetrabutylammonium difluoride was added to terminate the reaction to obtain a polymerization reaction solution;

[0154] A thin film evaporator was used to evaporate and remove unreacted isophorone diisocyanate monomer in the polymerization reaction liquid at a temperature of 200°C and an absolute pressure of 100 Pa to make its content 0.33wt%. The mass content of IPDI trimer (i.e., isocyanate of structure B) was 64%, and it was dissolved in butyl acetate to obtain a solution product with a solid content of 70%, thereby obtaining a polyisocyanate composition 3-1.

[0155] Comparative Example 2

[0156] Preparation of catalyst solution: Same as Example 3

[0157] 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 catalyst solution prepared above (the catalyst amount was 0.015% of the mass of IPDI) was added dropwise to the reaction system under stirring, and the reaction temperature was controlled between 70 and 80° C. to carry out polymerization reaction. When the NCO mass content of the reaction solution system was 25%, dibutyl phosphate in an amount equimolar to tetrabutylammonium difluoride was added to terminate the reaction to obtain a polymerization reaction solution.

[0158] A thin film evaporator was used to evaporate and remove unreacted isophorone diisocyanate monomer in the polymerization reaction liquid at a temperature of 200°C and an absolute pressure of 100 Pa to make its content 0.33wt%. The mass content of IPDI trimer (i.e., isocyanate of structure B) was 62%, and it was dissolved in butyl acetate to obtain a solution product with a solid content of 70%, thereby obtaining a polyisocyanate composition 3-2.

[0159] 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.

[0160] Table 1 Composition of polyisocyanate composition and storage stability test results

[0161]

[0162] The above results indicate that the solubility in non-polar solvents can be enhanced while avoiding an increase in downstream application viscosity by controlling the molar ratio of structure A / structure B isocyanurates.

[0163] Although the present invention 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 invention, the scope of the invention being 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, characterized in that 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, characterized in that The mass content of the isocyanurate of 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, characterized in that The mass content of isocyanate groups is 16-18%, preferably 16.5-17.5%.

5. The polyisocyanate composition according to any one of claims 1 to 4, characterized in that The polyisocyanate composition is dissolved in a solvent to obtain a polyisocyanate composition solution, wherein 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.; Preferably, the mass proportion of the solvent is 28-32%, based on the total mass of the polyisocyanate composition solution being 100%; Preferably, the polyisocyanate composition solution corresponding to the solution state after the polyisocyanate composition is dissolved in a solvent has an NCO group content of 11.2-12.8% by mass based on the total mass of the polyisocyanate composition solution being 100%.

6. The polyisocyanate composition according to any one of claims 1 to 5, characterized in that , wherein the content of isophorone diisocyanate monomer is less than 0.5wt%, preferably less than 0.35wt%, and more preferably less than 0.1wt%.

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