Organic-inorganic hybrid solid-phase catalyst and preparation method thereof, and preparation method of carbodiimide modified isocyanate

Abstract

The invention belongs to the technical field of isocyanate preparation, and particularly relates to an organic-inorganic hybrid solid-phase catalyst and a preparation method thereof, and a preparation method of carbodiimide modified isocyanate. The preparation method comprises the following steps: (1) carrying out grafting reaction on a coupling agent a and an inorganic silicon material b to obtain a reaction product c; and (2) reacting the reaction product c with a monomer d to obtain the catalyst. The catalyst prepared by the invention has the advantages of high reaction rate, no need of adding a terminating agent, simplified process flow, equipment investment saving, energy consumption saving and the like when being applied to preparation of carbodiimide modified isocyanate, and the obtained carbodiimide modified isocyanate product has the advantages of good storage stability, low VOC (volatile organic compound) content, low color number and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of isocyanate preparation, and specifically relates to an organic-inorganic hybrid solid phase catalyst and a preparation method thereof, and a preparation method of carbodiimide modified isocyanate. Background Art

[0002] Isocyanates are a very important class of chemical raw materials, which play a key role in the preparation of polyurethane foams, coatings, adhesives and other products. However, unmodified isocyanates have high reactivity, are easy to crystallize at room temperature, and have poor storage stability, which limits the application of isocyanates.

[0003] Isocyanate can be polycondensed under certain conditions to release CO2 to generate carbodiimide substances, which can further react with isocyanate to generate uretonimine. This modified isocyanate containing carbodiimide and uretonimine has a lower freezing point than ordinary isocyanate, is liquid at room temperature, has good storage stability, and is conducive to long-distance transportation and downstream applications. In addition, this modified isocyanate can make downstream products show characteristics such as light resistance, flame resistance, hydrolysis resistance, and increased initial strength.

[0004] The crude isocyanate products currently produced by the phosgene method contain multiple isomers and polycyclic heavy components generated by polymerization, so they need to be refined by vacuum distillation, rectification, crystallization and other operations to obtain pure isocyanate isomers or isocyanate mixtures of specific compositions. The refined isocyanate and the catalyst undergo polycondensation reaction at a certain reaction temperature to further obtain modified isocyanates containing carbodiimide and uretonimine. Therefore, the entire refining and reaction process generally needs to be completed through two or more tower equipment and reactors, and the process is relatively complicated.

[0005] The reaction catalysts for the polycondensation of isocyanate to carbodiimide mainly include phosphates, phosphorus heterocycles and organometallic catalysts, among which phosphates and phosphorus heterocycles are the most commonly used. Phosphates have weak catalytic ability and are inefficient catalysts, so the catalyst dosage and catalytic temperature are both high, and the catalyst residue in the product may cause problems such as VOC exceeding the standard for downstream products, but it is relatively stable when stored at room temperature. Phosphorus heterocycles are highly efficient catalysts, and a high catalytic effect can be achieved by adding a small amount of catalyst, but terminators need to be added after the reaction is completed, and slow polycondensation reactions will still occur during storage after termination, and terminators are easy to react with carbodiimide to generate color-producing substances, resulting in a high color number. On the one hand, it causes the product indicators to deteriorate, and on the other hand, the gas produced by the polycondensation reaction will also cause the storage container to increase in pressure. This situation is more obvious when the ambient temperature is high, and there are quality failures and safety risks; and the content of polycyclic heavy components in the obtained product accounts for a high proportion, resulting in a high crystallization point and product color number of the product.

[0006] In summary, the existing method of preparing carbodiimide-modified isocyanate using phosphates and phosphorus heterocyclic catalysts has problems with storage stability, high VOC content, high crystallization point, color number fluctuation and other product quality issues, and the process of refining the isocyanate mixture before polycondensation reaction is relatively complicated. Summary of the invention

[0007] In response to the above problems, this patent solves the defects of the carbodiimide-modified isocyanate prepared by the prior art, such as poor storage stability, high VOC content, high crystallization temperature, color number fluctuation, and the need for refining before polycondensation reaction, resulting in a complicated process. It provides an organic-inorganic hybrid solid phase catalyst and preparation method, and a preparation method of carbodiimide-modified isocyanate.

[0008] To this end, the present invention provides the following technical solutions.

[0009] The first aspect of the present invention provides a method for preparing an organic-inorganic hybrid solid phase catalyst, comprising the following steps:

[0010] (1) coupling agent a and inorganic silicon material b undergo grafting reaction to obtain reaction product c;

[0011] (2) reacting the reaction product c with the monomer d to obtain a catalyst;

[0012] The monomer d is selected from the following structural formula:

[0013]

[0014] wherein R1, R2, R3 and R4 are independently selected from a hydrogen atom, a substituted or unsubstituted alkyl group, and an amino group, and at least one of R1, R2, R3 and R4 is an amino group;

[0015] R5 is a C1-C5 alkyl or aryl group;

[0016] R6 is an oxygen atom or a sulfur atom.

[0017] In an optional embodiment, R1, R2, R3 and R4 are independently selected from a hydrogen atom, a C1-C8 unsubstituted alkyl group or an amino group, and at least one of R1, R2, R3 and R4 is an amino group;

[0018] Preferably, R1 is an amino group; R2 is selected from a hydrogen atom or a C1-C4 alkyl group; R3 is selected from a hydrogen atom or a C1-C3 alkyl group; R4 is selected from a hydrogen atom or a C1-C3 alkyl group; R5 is selected from a C1-C5 alkyl group or a C6-C18 aryl group;

[0019] Preferably, the monomer d is selected from the following structural formula:

[0020]

[0021] Preferably, the monomer d is selected from one of the following structural formulas:

[0022]

[0023] In an optional embodiment, the coupling agent a is a silane coupling agent; the general structural formula of the coupling agent is YR-Si(OR), Y represents bromopropyl and / or aminopropyl, R represents alkyl, and OR represents alkoxy.

[0024] Preferably, the coupling agent a is at least one of 3-bromopropyltrimethoxysilane, aminopropyltriethoxysilane and aminopropyltrimethoxysilane;

[0025] Preferably, the inorganic silicon material b is at least one of silicon dioxide and molecular sieve;

[0026] Preferably, the silicon dioxide is amorphous silicon dioxide.

[0027] Preferably, the molecular sieve includes a zeolite molecular sieve or a mesoporous molecular sieve; in the present invention, the zeolite molecular sieve includes at least one of A-type, X-type, Y-type, ZSM series, MFI type molecular sieve, etc.; the mesoporous molecular sieve includes at least one of MCM series, SBA series molecular sieve, etc.;

[0028] Preferably, the inorganic silicon material b is a mesoporous molecular sieve. Further preferably, the inorganic silicon material b is an MCM series molecular sieve.

[0029] In an optional embodiment, the mass ratio of the coupling agent a to the inorganic silicon material b is (0.5-10):1; and / or,

[0030] The mass ratio of the reaction product c to the monomer d is 1:(0.5-5).

[0031] It should be noted that the mass ratio of coupling agent a to inorganic silicon material b is (0.5-10):1, ensuring an excess of coupling agent and the grafting amount of coupling agent in the inorganic silicon material. The mass ratio of reaction product c to monomer d is 1:(0.5-5), ensuring a certain amount of monomer d is grafted onto reaction product c.

[0032] In an optional embodiment, in step (1), the grafting reaction is refluxed for 4-20 hours under a protective gas, and the protective gas may be nitrogen, argon, helium, etc.; and / or,

[0033] The step (1) is carried out under the condition of an organic solvent, wherein the organic solvent is at least one of chloroform, dichloroethane and trichloroethane, preferably, the organic solvent is chloroform; and / or,

[0034] The step (2) is refluxed for 5-24 hours under a basic catalyst; and / or,

[0035] The step (2) is carried out under the condition of an organic solvent, wherein the organic solvent is at least one of acetonitrile, tetrahydrofuran, methyl tert-butyl ether, acetone and N-N-dimethylformamide, preferably acetonitrile.

[0036] In an optional embodiment, the alkaline catalyst is at least one of potassium carbonate, sodium carbonate, potassium bicarbonate and sodium bicarbonate;

[0037] Preferably, the alkaline catalyst is potassium carbonate.

[0038] In an optional embodiment, the step (2) further includes a granulation step;

[0039] Preferably, the particle size after granulation is 0.2-5 mm.

[0040] In an optional embodiment, the granulation step further includes filtering, washing, drying and the like. When washing, the solvent may be any solvent such as water, methanol, ethanol, etc. Filtration, washing and drying are performed according to methods known in the art.

[0041] The second aspect of the present invention provides an organic-inorganic hybrid solid phase catalyst prepared by the above preparation method.

[0042] The third aspect of the present invention provides a method for preparing carbodiimide-modified isocyanate, comprising adding the organic-inorganic hybrid solid phase catalyst prepared by the above preparation method into isocyanate, and catalyzing polymerization to obtain carbodiimide-modified isocyanate.

[0043] The carbodiimide modified isocyanate of the present invention is a product with an isocyanate (NCO) content of 28%-30%. When the isocyanate does not meet this requirement, it is considered as a substandard product, even if other properties are excellent.

[0044] Isocyanate is a general term for various esters of isocyanic acid, including one or more of the isocyanate compounds commonly found in the art, such as aromatic, aromatic aliphatic, aliphatic and alicyclic diisocyanates, etc. Specifically, isocyanate includes any one or more of diphenylmethane diisocyanate, polyphenylmethane polyisocyanate, toluene diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, hexamethylene diisocyanate, etc., preferably diphenylmethane diisocyanate.

[0045] In an optional embodiment, the catalytic polymerization temperature is 120-200°C and the time is 10-90min;

[0046] Preferably, the temperature of the catalytic polymerization is 180-190°C, and the time is 10-20min; it should be noted that the catalyst provided by the present invention can be applied to higher polymerization reaction temperatures and can accelerate the catalytic rate. As an example, the temperature of the catalytic polymerization is 120°C, 130°C, 140°C, 150°C, 160°C, 170°C, 180°C, 190°C, 200°C or within the range formed by any two of the above values; the reaction time is 10min, 20min, 30min, 40min, 50min, 60min, 70min, 80min, 90min or within the range formed by any two of the above values. Preferably, the catalytic polymerization reaction is carried out in a distillation tower;

[0047] Preferably, based on the mass of isocyanate, the amount of the organic-inorganic hybrid solid phase catalyst added is 0.1-5%. Preferably, based on the mass of isocyanate, the amount of the organic-inorganic hybrid solid phase catalyst added is 1.5-3.5%.

[0048] The method for preparing carbodiimide modified isocyanate provided by the present invention adopts a reaction distillation tower for catalytic polymerization, fills the catalyst into the reaction section of the reaction distillation tower, and separates the isocyanate mixture by the process of the reaction section while preparing the carbodiimide modified isocyanate product.

[0049] The reaction distillation tower includes a reaction section and a distillation section. Isocyanate is fed into the distillation section. After separation in the distillation section, part of it is taken out from the side line as a product, and part of it is contacted with the catalyst in the reaction section to react to obtain a carbodiimide modified isocyanate product, which is taken out from the side line; the light component is taken out from the top of the tower, and the heavy component is taken out from the bottom of the tower.

[0050] In an optional embodiment, the number of theoretical plates of the reactive distillation tower is 10-40.

[0051] The technical solution of the present invention has the following advantages:

[0052] 1. A method for preparing an organic-inorganic hybrid solid phase catalyst provided by the present invention, the preparation method comprising: (1) carrying out a grafting reaction between a coupling agent a and an inorganic silicon material b to obtain a reaction product c; (2) reacting the reaction product c with a monomer d to obtain a catalyst. The use of the catalyst prepared by the present invention to prepare carbodiimide-modified isocyanate has the advantages of fast reaction rate, no need to add a terminator, simplified process flow, saving equipment investment and energy consumption, etc. The obtained carbodiimide-modified isocyanate product has the advantages of good storage stability, low VOC content, low color number, etc. Since the distillation tower reactor has certain requirements on temperature and needs to be carried out under the condition of about 180°C, and the existing solid phase catalyst is not suitable for the reaction temperature, the catalyst provided by the present invention uses carbodiimide-modified isocyanate and is suitable for a distillation reaction tower of about 180°C, and is separated while carrying out the catalytic polymerization reaction, reducing by-products in the product, such as multi-ring heavy components in six to ten rings, and the obtained product has a lower crystallization temperature and better low-temperature storage performance, and the reaction and separation are carried out in the same equipment, which shortens the reaction time and improves the reaction efficiency.

[0053] 2. The preparation method of carbodiimide-modified isocyanate provided by the present invention, applying the catalyst of the present invention to carbodiimide-modified isocyanate, can realize the separation of isocyanate mixture and the production of carbodiimide-modified isocyanate in the same equipment (reaction distillation tower), the catalyst meets the temperature requirements of the reaction distillation tower, saves equipment investment and energy consumption, and the crystallization temperature of the modified isocyanate product obtained is reduced, and the storage and use conditions are significantly improved.

[0054] The crystallization temperature of the carbodiimide modified isocyanate product prepared by using the catalyst of the present invention is reduced, the low-temperature storage stability is enhanced, the low-temperature storage time at 0°C is extended to 60 days, the platinum-cobalt color number is 10-20, the content of six-ring to ten-ring polycyclic heavy component by-products in the product accounts for no more than 6%, and the reduction of polycyclic heavy components in the product is conducive to further improving the low-temperature storage performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0056] Figure 1 It is a distillation reaction tower used in preparing carbodiimide-modified isocyanate in Example 1 of the present invention;

[0057] Reference numerals:

[0058] 1-feed inlet; 2-tower top outlet; 3-first side outlet; 4-second side outlet; 5-third side outlet; 6-tower bottom outlet. DETAILED DESCRIPTION

[0059] The following examples are provided for a better understanding of the present invention, but are not intended to limit the best mode of implementation, nor to limit the content and protection scope of the present invention. Any product identical or similar to the present invention obtained by anyone under the inspiration of the present invention or by combining the features of the present invention with other prior arts shall fall within the protection scope of the present invention.

[0060] If no specific experimental steps or conditions are specified in the examples, the conventional experimental steps or conditions described in the literature in the field can be used. If no manufacturer is specified for the reagents or instruments used, they are all conventional reagent products that can be obtained commercially.

[0061] Example 1

[0062] This embodiment provides a method for preparing an organic-inorganic hybrid solid phase catalyst, comprising the following steps:

[0063] (1) 10 g of MCM-41 molecular sieve solid and 10 g of coupling agent 3-bromopropyltrimethoxysilane were added to 150 mL of dried chloroform solvent, and refluxed for 10 h under nitrogen protection. The supernatant was removed by centrifugation, washed with ether, and stirred in ether solvent for 10 h. The filtered solid was dried under vacuum at 80° C. to obtain reaction product c.

[0064] (2) 3.0 g of monomer d having a structure as shown in the figure below, 5.0 g of reaction product c, and 4.5 g of potassium carbonate solid were added to 200 mL of acetonitrile, and the mixture was refluxed for 8 h under stirring.

[0065] (3) After filtering the product obtained in step (2), a solid phase catalyst is obtained, which is washed with deionized water and methanol, dried in vacuo at 80° C., and pressed into granules with a tablet press, with a particle size of 1-2 mm, to obtain a final catalyst.

[0066]

[0067] This embodiment also provides a method for preparing carbodiimide modified isocyanate, comprising the following steps:

[0068] Using a diphenylmethane diisocyanate mixture as a raw material, the solid phase catalyst is filled into the reaction section of a distillation reaction tower. The structure of the distillation reaction tower is shown in FIG. Figure 1The catalyst is fixed on both the upper and lower sides with metal Raschig rings to prevent the catalyst particles from being taken out. The filling amount of the catalyst is 3wt% of the weight of the diphenylmethane diisocyanate mixture, and the number of theoretical plates in the distillation section is 40. The diphenylmethane diisocyanate mixture is composed of: chlorobenzene: 0.01wt%; 2,2-MDI: 1wt%; 2,4-MDI: 18wt%; 4,4-MDI: 80wt%; heavy components: 0.99wt%; heavy components refer to components with a boiling point higher than MDI.

[0069] The diphenylmethane diisocyanate mixture is fed from the feed port 1 of the rectifying section at the upper end of the reaction section. After separation in the rectifying section, 3wt% of the feed is extracted from the first side extraction port 3 as an isocyanate product of a specific composition, 18wt% of the feed is extracted from the second side extraction port 4 as an isocyanate product of a specific composition, 4.9wt% of the feed is extracted from the tower bottom outlet 6, 0.1wt% of the feed is extracted from the tower top outlet 2, and the rest is contacted with the catalyst of the reaction section for 18 minutes to undergo a polycondensation reaction to generate a modified isocyanate containing carbodiimide and uretonimine, which is extracted from the side extraction port 5. The temperature of the reaction section is 188°C. Among them, the light component is extracted from the tower top outlet 2, the heavy component is extracted from the tower bottom 6, the first product is extracted from the first side extraction port 3, the second product is extracted from the second side extraction port 4, and the carbodiimide modified isocyanate is extracted from the third side extraction port 5. The composition and mass content of each material are shown in the following table:

[0070] Table 1 Composition and mass content of each material

[0071]

[0072] Example 2

[0073] This embodiment provides a method for preparing an organic-inorganic hybrid solid phase catalyst, which is basically the same as the method in Example 1, except that R2 and R3 in monomer d are both methyl groups, and the structural formula is as follows:

[0074]

[0075] This embodiment also provides a method for preparing carbodiimide-modified isocyanate, which is the same as that in Example 1.

[0076] Example 3

[0077] This embodiment provides a method for preparing an organic-inorganic hybrid solid phase catalyst, which is basically the same as the method in Example 1, except that the inorganic silicon material is ZSM-5, and its mass dosage is the same as that of MCM-41 molecular sieve.

[0078] This embodiment also provides a method for preparing carbodiimide-modified isocyanate, which is the same as that in Example 1.

[0079] Example 4

[0080] This embodiment provides a method for preparing an organic-inorganic hybrid solid phase catalyst, which is the same as that of Example 1.

[0081] This embodiment also provides a method for preparing carbodiimide modified isocyanate, which is basically the same as the method in Example 1, except that the contact reaction time between the reaction section and the catalyst is adjusted from 18 min to 90 min, and the temperature of the reaction section is adjusted from 188° C. to 120° C.

[0082] Example 5

[0083] This embodiment provides a method for preparing an organic-inorganic hybrid solid phase catalyst, which is basically the same as the method in Example 1, except that the structural formula of monomer d is as follows:

[0084]

[0085] This embodiment also provides a method for preparing carbodiimide-modified isocyanate, which is the same as that in Example 1.

[0086] Example 6

[0087] This embodiment provides a method for preparing an organic-inorganic hybrid solid phase catalyst, which is basically the same as the method in Example 1, except that the structural formula of monomer d is as follows:

[0088]

[0089] This embodiment also provides a method for preparing carbodiimide-modified isocyanate, which is the same as that in Example 1.

[0090] Comparative Example 1

[0091] This comparative example provides a catalyst, which is different from Example 1 in that the following compound is used to replace the monomer d in Example 1.

[0092]

[0093] This comparative example also provides a method for preparing carbodiimide-modified isocyanate, which is the same as that in Example 1.

[0094] Test example

[0095] This test example provides the performance test of the above-mentioned embodiment and comparative example products, and the test results are shown in Table 2;

[0096] (1) Test method for the color number of carbodiimide modified isocyanate products: Determine the platinum-cobalt color number by colorimetric method.

[0097] (2) Test method for low temperature storage performance of carbodiimide modified isocyanate products: Conduct low temperature crystallization tests at 5°C, 0°C, and 5°C, and record the time when low temperature crystallization occurs.

[0098] (3) Testing method for by-product content in carbodiimide-modified isocyanate products: GPC chromatography tests the components of carbodiimide-modified isocyanate products.

[0099] Table 2 Performance test results

[0100]

[0101] Conclusion: From the above results, the carbodiimide modified isocyanate product prepared by the organic-inorganic hybrid solid phase catalyst prepared by the present invention has good storage stability, platinum cobalt color number 10-20, and the content of six-ring to ten-ring polycyclic heavy component by-products is not higher than 6%. From Comparative Example 1, when the catalyst prepared by using a compound different from the monomer d structure of the present invention is used as a catalyst for carbodiimide modified isocyanate, the NCO content is higher than 30%, which is an unqualified product. The P=O bond is connected with an oxygen atom, the catalytic effect is poor, and the obtained NCO content is high. It is further explained that the NCO content of the carbodiimide modified isocyanate prepared by the catalyst of the present invention meets the requirements and is a qualified product.

[0102] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from these are still within the scope of protection of the invention.

Claims

1. A method for preparing an organic-inorganic hybrid solid phase catalyst, characterized in that: The following steps are involved: (1) coupling agent a and inorganic silicon material b undergo grafting reaction to obtain reaction product c; (2) reacting the reaction product c with the monomer d to obtain a catalyst; The monomer d is selected from the following structural formula: wherein R1, R2, R3 and R4 are independently selected from a hydrogen atom, a substituted or unsubstituted alkyl group, and an amino group, and at least one of R1, R2, R3 and R4 is an amino group; R5 is a C1-C5 alkyl or aryl group; R6 is an oxygen atom or a sulfur atom.

2. The preparation method according to claim 1, characterized in that: R1, R2, R3 and R4 are independently selected from a hydrogen atom, a C1-C8 unsubstituted alkyl group or an amino group, and at least one of R1, R2, R3 and R4 is an amino group; Preferably, R1 is an amino group; R2 is selected from a hydrogen atom or a C1-C4 alkyl group; R3 is selected from a hydrogen atom or a C1-C3 alkyl group; R4 is selected from a hydrogen atom or a C1-C3 alkyl group; R5 is selected from a C1-C5 alkyl group or a C6-C18 aryl group; Preferably, the monomer d is selected from the following structural formula: Preferably, the monomer d is selected from at least one of the following structural formulas:

3. The preparation method according to claim 1 or 2, characterized in that: The coupling agent a is a silane coupling agent; Preferably, the coupling agent a is at least one of 3-bromopropyltrimethoxysilane, aminopropyltriethoxysilane and aminopropyltrimethoxysilane; Preferably, the inorganic silicon material b is at least one of silicon dioxide and molecular sieve; Preferably, the molecular sieve comprises a zeolite molecular sieve or a mesoporous molecular sieve; Preferably, the inorganic silicon material b is a mesoporous molecular sieve.

4. The preparation method according to any one of claims 1 to 3, characterized in that The mass ratio of the coupling agent a to the inorganic silicon material b is (0.5-10):1; and / or, The mass ratio of the reaction product c to the monomer d is 1:(0.5-5).

5. The preparation method according to any one of claims 1 to 4, characterized in that: In the step (1), the grafting reaction is refluxed under protective gas for 4-20 hours; and / or, The step (1) is carried out under the condition of an organic solvent, wherein the organic solvent is at least one of chloroform, dichloroethane and trichloroethane; and / or, The step (2) is refluxed for 5-24 hours under a basic catalyst; and / or, The step (2) is carried out under the condition of an organic solvent, and the organic solvent is at least one of acetonitrile, tetrahydrofuran, methyl tert-butyl ether, acetone and NN dimethylformamide.

6. The preparation method according to claim 5, characterized in that: The alkaline catalyst is at least one of potassium carbonate, sodium carbonate, potassium bicarbonate and sodium bicarbonate; Preferably, the alkaline catalyst is potassium carbonate; Preferably, the organic solvent is acetonitrile.

7. The preparation method according to any one of claims 1 to 6, characterized in that: The step (2) further includes a granulation step; Preferably, the particle size after granulation is 0.2-5 mm.

8. The organic-inorganic hybrid solid phase catalyst prepared by the preparation method according to any one of claims 1 to 7.

9. A method for preparing a carbodiimide modified isocyanate, characterized in that: The method comprises adding an organic-inorganic hybrid solid phase catalyst prepared by the preparation method according to any one of claims 1 to 7 to isocyanate, and catalyzing polymerization to obtain carbodiimide-modified isocyanate.

10. The preparation method according to claim 9, characterized in that: The catalytic polymerization temperature is 120-200°C and the time is 10-90min; Preferably, the temperature of the catalytic polymerization is 180-190°C; Preferably, the catalytic polymerization reaction is carried out in a distillation tower; Preferably, based on the mass of isocyanate, the addition amount of the organic-inorganic hybrid solid phase catalyst is 0.1-5%.

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