Nicotinic acid modified pyridoxamine polyether polyol and preparation method thereof

Abstract

The invention belongs to the technical field of polyether polyol and preparation thereof, and particularly relates to nicotinic acid modified pyridoxamine polyether polyol and a preparation method thereof. The preparation method of the nicotinic acid modified pyridoxamine polyether polyol comprises the following steps: carrying out reaction on pyridoxamine and a phosphoric acid aqueous solution to convert pyridoxamine phosphate, carrying out esterification reaction on nicotinic acid and pyridoxamine phosphate under the action of a catalyst sulfuric acid, and dehydrating to obtain nicotinic acid pyridoxamine ester; then, by taking pyridoxamine nicotinate and liquid small-molecular alcohol as initiators, under the action of a basic catalyst, carrying out polymerization reaction on pyridoxamine nicotinate and liquid small-molecular alcohol and alkylene oxide, and carrying out post-treatment, so as to obtain the nicotinic acid modified pyridoxamine phosphate polyether polyol. According to the preparation method of the nicotinic acid modified pyridoxamine polyether polyol, the raw materials are simple and environment-friendly, and melamine does not need to be introduced; the nicotinic acid modified pyridoxamine polyether polyol prepared by adopting the preparation method disclosed by the invention is excellent in flame retardant property, high in compression strength and good in pentane solubility.

Description

Technical Field

[0001] The invention belongs to the technical field of polyether polyols and preparation thereof, and specifically relates to a nicotinic acid modified pyridoxamine polyether polyol and a preparation method thereof. Background Art

[0002] Polyether polyol (abbreviated as polyether) is a polymer compound, which is obtained by polyaddition reaction of initiator with ethylene oxide, propylene oxide, etc. under the action of catalyst. Polyether polyol has the characteristics of high molecular weight, low viscosity, high activity and hydrophilicity. It is an important raw material for manufacturing polyurethane plastics and foams. It is widely used in the fields of car seats, furniture, building insulation, etc. In addition, polyether polyol can also be used as epoxy resin prepolymer, antistatic agent, lubricant, etc.

[0003] At present, widely used initiators include sucrose, glycerol, sorbitol and diethanolamine. The polyether polyols produced by these initiators have different compound structures and show diverse performance in rigid polyurethane foam plastics.

[0004] CN112011022A discloses a method for preparing a phosphorus-containing flame-retardant polyurethane elastomer, which comprises the following steps: performing an addition reaction between a phosphate ester and a 4-hydroxybutyric acid solution, then performing an esterification reaction with 2-methyl-2,4-pentanediol, and finally uniformly mixing with a diisocyanate to introduce a single phosphorus element. The method has a certain flame-retardant effect, but there is a certain gap compared with the flame-retardant effect of a nitrogen-phosphorus synergistic system. Even if the nitrogen element is introduced in the process of preparing the decomposer, the process is complicated, the preparation cycle is long, and the nitrogen content is low.

[0005] CN117264192A discloses a method for preparing a highly efficient, environmentally friendly, flame-retardant polyether polyol. The process is characterized by the use of an amino provider consisting of a mixture of melamine and benzoguanamine, the high nitrogen content of which effectively improves the flame retardant properties of polyurethane foam; however, the solubility of melamine is poor, resulting in a low yield of the final synthesized polyether polyol.

[0006] Therefore, it is necessary to develop a polyether polyol with simple raw materials, excellent mechanical properties, easy solubility, and good flame retardant properties. Summary of the invention

[0007] The technical problem to be solved by the present invention is to overcome the defects of the prior art and provide a preparation method of nicotinic acid modified pyridoxamine polyether polyol, which has simple raw materials, is environmentally friendly, and does not require the introduction of melamine; the nicotinic acid modified pyridoxamine polyether polyol prepared by the preparation method of the present invention has excellent flame retardant properties, high compression strength, and good pentane solubility.

[0008] The preparation method of the nicotinic acid modified pyridoxamine polyether polyol of the present invention comprises the following steps: pyridoxamine and a phosphoric acid aqueous solution are reacted to convert into pyridoxamine phosphate, nicotinic acid and pyridoxamine phosphate are subjected to an esterification reaction under the action of a catalyst, sulfuric acid, and nicotinic acid pyridoxamine ester is obtained after dehydration, and then nicotinic acid pyridoxamine ester and a liquid small molecule alcohol are used as initiators to carry out a polymerization reaction with an alkylene oxide under the action of an alkaline catalyst, and after post-treatment, the nicotinic acid modified pyridoxamine phosphate polyether polyol is obtained.

[0009] The specific synthesis process of the pyridoxamine phosphate is as follows: pyridoxamine and 75wt.% phosphoric acid aqueous solution are added in a reaction kettle in a mass ratio of (1-1.68):1, and then a solvent is added, dissolved at room temperature, the temperature is maintained at 105-110°C, the pressure is maintained at -0.08-0.1MPa, and vacuum bubbling dehydration is performed to obtain pyridoxamine phosphate; wherein the solvent is one or both of ethanol and chloroform.

[0010] The specific synthesis process of the nicotinate pyridoxamine ester is as follows: nicotinic acid and pyridoxamine phosphate in a molar ratio of (1-1.8):1 are added into a reaction kettle, and then 97wt.% sulfuric acid is added to carry out an esterification reaction at 200-220°C, and nicotinate pyridoxamine ester is generated after dehydration; wherein the amount of 97wt.% sulfuric acid added is 0.03% of the mass of pyridoxamine phosphate.

[0011] The specific synthesis process of the polymerization reaction is as follows: nicotinate pyridoxamine ester, liquid small molecule alcohol and alkaline catalyst are added into a reaction kettle, and the temperature is increased in vacuum after nitrogen replacement, the temperature is maintained at 80-85°C and the pressure is 0.1-0.4MPa, and alkylene oxide is added dropwise, and the reaction is matured for 1-2h after the addition is completed; the temperature is continued to be increased, the temperature is controlled at 105-110°C and the pressure is 0.1-0.4MPa, and the alkylene oxide is continued to be added dropwise, and when the reaction pressure remains basically unchanged after the feeding is completed, the pressure is supplemented to 0.2-0.3MPa, and the reaction is matured for 2-3h; wherein, when the alkaline catalyst used is dimethylamine, the alkaline catalyst needs to be vacuum pumped in after the nitrogen replacement is completed.

[0012] Preferably, when liquid sorbitol is used as one of the raw materials, a dehydration step is added after the first stage of aging reaction, and the specific steps are: after the aging is completed, the temperature is raised to 110° C., vacuum is drawn and nitrogen is bubbled for 1.5 hours, and the pressure is maintained at -0.09±-0.01 MPa to remove water from the liquid sorbitol.

[0013] The post-treatment process is as follows: the system after the polymerization reaction is kept warm to 105-110° C., the pressure is then maintained at -0.08-0.1 MPa, nitrogen is bubbled for 1-2 hours, and nicotinic acid modified pyridoxamine phosphate polyether polyol is obtained by filtration.

[0014] The liquid small molecule alcohol is two or three of diethylene glycol, liquid sorbitol, and glycerol, wherein the liquid sorbitol has a water content of 30 wt.%, and is purchased from Shandong Tianli Pharmaceutical Co., Ltd.

[0015] The alkylene oxide is one or both of propylene oxide and ethylene oxide.

[0016] The total amount of the nicotinate pyridoxamine ester and the liquid small molecule alcohol added is 42.5-45.5wt.% of the total amount of the alkylene oxide added.

[0017] The amount of alkylene oxide added in the first stage is 14.5-21.5 wt.% of the total amount of alkylene oxide added.

[0018] The alkaline catalyst is one or two of 2,4,6-tris(dimethylaminomethyl)phenol, N,N-dimethylcyclohexylamine and dimethylamine.

[0019] A nicotinic acid modified pyridoxamine polyether polyol is prepared by the preparation method of the nicotinic acid modified pyridoxamine polyether polyol.

[0020] Specifically, the preparation method of the nicotinic acid modified pyridoxamine polyether polyol comprises the following steps: (1) Preparation of pyridoxamine phosphate: Pyridoxamine and 75 wt.% phosphoric acid aqueous solution in a mass ratio of (1-1.68):1 are added to a reaction kettle, and then a solvent is added and dissolved at room temperature, and then the temperature is increased, the temperature is maintained at 107.5±2.5°C, the pressure is maintained at -0.09±0.01 MPa, and vacuum bubbling dehydration is performed for 1.5 hours to obtain pyridoxamine phosphate; wherein the solvent is one or both of ethanol and chloroform; (2) Preparation of pyridoxamine nicotinate: Nicotinic acid and pyridoxamine phosphate were added in a molar ratio of (1-1.8):1 into a reaction kettle, and then 97wt.% sulfuric acid with a mass of 0.03% pyridoxamine phosphate was added, and an esterification reaction was carried out at 200-220°C. After bubbling dehydration for 1.5h, pyridoxamine nicotinate was generated; (3) Polymerization reaction: Pyridoxamine nicotinate, liquid small molecule alcohol and alkaline catalyst were added to a 2L autoclave equipped with a stirrer, a meter, a heating and temperature control device, a cooling device (including an outer jacket and an inner coil) and a pressure sensor. Nitrogen was filled into the autoclave for leak testing. The autoclave was replaced with nitrogen while ensuring that the autoclave was well sealed. After nitrogen replacement, the temperature was raised to 82.5±2.5℃ and the pressure was 0.25±0.15MPa. Alkylene oxide was added dropwise. After the addition was completed, the reaction mixture was aged for 1~2h. The temperature was continued to rise and controlled at 107. 5±2.5℃, pressure 0.25±0.15MPa, continue to drop alkylene oxide, after the feeding is completed, when the reaction pressure remains basically unchanged, supplement the pressure to 0.2~0.3MPa, and mature for 2~3h; wherein, when the alkaline catalyst used is dimethylamine, the alkaline catalyst needs to be replaced with nitrogen and then vacuum pumped in; when liquid sorbitol is used as one of the raw materials, after the first stage of aging reaction, heat to 110℃, vacuum pump and nitrogen bubble for 1.5h, and maintain the pressure at -0.09±0.01MPa to remove moisture from the liquid sorbitol; (4) Post-treatment: The matured polyether is kept at 107.5±2.5°C, and then the pressure is maintained at -0.09±0.01MPa, and nitrogen is bubbled. After bubbling for 1~2h, the material is discharged and filtered to obtain nicotinic acid modified pyridoxamine phosphate polyether polyol.

[0021] Compared with the prior art, the present invention has the following beneficial effects: (1) The preparation method of the nicotinic acid modified pyridoxamine phosphate polyether polyol of the present invention comprises the following steps: pyridoxamine is converted into a derivative containing multiple alcoholic hydroxyl groups, namely, pyridoxamine phosphate, by phosphorylation of pyridoxamine, thereby increasing the number of hydroxyl groups, effectively improving the functionality, and further improving the reaction efficiency of the polymerization reaction; secondly, nicotinic acid pyridoxamine ester is generated by an esterification reaction between nicotinic acid and pyridoxamine phosphate. The presence of ester groups and ether bonds makes the nicotinic acid modified pyridoxamine phosphate polyether polyol have good solubility, thereby improving the pentane miscibility of the product.

[0022] (2) The preparation method of the nicotinic acid modified pyridoxamine phosphate polyether polyol of the present invention uses ethanol and chloroform as solvents, and the solvents can be recycled and reused. Secondly, nicotinic acid and pyridoxamine are used as raw materials, and the raw materials are environmentally friendly.

[0023] (3) The nicotinic acid modified pyridoxamine phosphate polyether polyol prepared by the method of the present invention contains nitrogen, phosphorus, halogen and pyridine structures, which reduces the deformation between molecular chains. The product has excellent flame retardant properties, high activity and excellent compressive strength. DETAILED DESCRIPTION

[0024] The present invention is further described below with reference to the following examples and comparative examples. The raw materials used in the examples, unless otherwise specified, are all commercially available conventional raw materials; the process methods used in the examples, unless otherwise specified, are all conventional methods in the art.

[0025] Example 1 The preparation method of the nicotinic acid modified pyridoxamine polyether polyol comprises the following steps: (1) Preparation of pyridoxamine phosphate: 168 g of pyridoxamine and 130 g of 75 wt.% phosphoric acid aqueous solution were added to a reaction kettle, followed by addition of ethanol and chloroform, dissolved at room temperature, and then heated, maintaining the temperature at 107.5±2.5°C, maintaining the pressure at -0.09±0.01 MPa, and vacuum bubbling dehydration for 1.5 h to obtain pyridoxamine phosphate; (2) Preparation of pyridoxamine nicotinate: Nicotinic acid and pyridoxamine phosphate were added in a molar ratio of 1.4:1 into a reaction kettle, and then 97wt.% sulfuric acid with a mass ratio of 0.03% of pyridoxamine phosphate was added, and an esterification reaction was carried out at 210°C. After bubbling dehydration for 1.5 hours, pyridoxamine nicotinate was generated; (3) Polymerization reaction: In a 2L autoclave equipped with a stirrer, a meter, a heating and temperature control device, a cooling device (including an outer jacket and an inner coil) and a pressure sensor, 300g of liquid sorbitol, 50g of diethylene glycol, 200g of glycerol, 200g of nicotinate pyridoxamine, and 7g of N,N-dimethylcyclohexylamine were added, and nitrogen was filled into the autoclave for leak testing. While ensuring that the autoclave was well sealed, nitrogen was replaced in the autoclave. After nitrogen replacement, 11g of dimethylamine was vacuum-drawn in, and then the temperature was raised to 82.5±2 .5℃, pressure 0.25±0.15MPa, add 247g ethylene oxide dropwise, mature for 1h after the addition is completed, then raise the temperature in the kettle to 110℃, evacuate and bubble nitrogen to maintain the pressure -0.09±0.01MPa for 1.5h to remove the moisture in the liquid sorbitol; control the temperature to 107.5±2.5℃, pressure 0.25±0.15MPa, continue to add 1410g propylene oxide dropwise, and when the reaction pressure remains basically unchanged after the feeding is completed, make up the pressure to 0.2MPa and mature for 2h; (4) Post-treatment: The matured polyether was kept at 107.5±2.5°C, and then the pressure was maintained at -0.09±0.01MPa, and nitrogen was bubbled. After bubbling for 1h, the material was discharged and filtered to obtain nicotinic acid modified pyridoxamine phosphate polyether polyol. The hydroxyl value and viscosity (25°C) of this rigid foam polyether polyol were tested to be 415mgKOH / g and 4270MPa·s.

[0026] Example 2 The preparation method of the nicotinic acid modified pyridoxamine polyether polyol comprises the following steps: (1) Preparation of pyridoxamine phosphate: 168 g of pyridoxamine and 100 g of 75 wt.% phosphoric acid aqueous solution were added to a reaction kettle, followed by addition of chloroform, which was dissolved at room temperature, and then heated, maintaining the temperature at 107.5±2.5°C, maintaining the pressure at -0.09±0.01 MPa, and vacuum bubbling dehydration for 1.5 h to obtain pyridoxamine phosphate; (2) Preparation of pyridoxamine nicotinate: Nicotinic acid and pyridoxamine phosphate were added in a molar ratio of 1:1 into a reaction kettle, and then 97wt.% sulfuric acid with a mass of 0.03% pyridoxamine phosphate was added, and an esterification reaction was carried out at 200°C. After bubbling dehydration for 1.5 hours, pyridoxamine nicotinate was generated; (3) Polymerization reaction: In a 2L autoclave equipped with a stirrer, a meter, a heating and temperature control device, a cooling device (including an outer jacket and an inner coil) and a pressure sensor, 360g of liquid sorbitol, 100g of diethylene glycol and 130g of pyridoxamine nicotinate were added, and nitrogen was introduced to test the reactor for leaks. While ensuring that the reactor was well sealed, nitrogen was replaced. After nitrogen replacement was completed, 7g of dimethylamine was vacuum-drawn in, and then the temperature was raised to 82.5±2.5℃ and the pressure was 0.25±0.15MPa. , add 281g of propylene oxide dropwise, mature for 1.5h after the addition is completed, then raise the temperature in the kettle to 110℃, evacuate and bubble nitrogen to maintain the pressure at -0.09±0.01MPa for 1.5h to remove the moisture in the liquid sorbitol; after adding 6g of dimethylamine, control the temperature at 107.5±2.5℃ and the pressure at 0.25±0.15MPa, continue to add 1041g of propylene oxide dropwise, and when the reaction pressure remains basically unchanged after the feeding is completed, add the pressure to 0.25MPa and mature for 2.5h; (4) Post-treatment: The matured polyether was kept at 107.5±2.5°C, and then the pressure was maintained at -0.09±0.01MPa, and nitrogen was bubbled. After bubbling for 1.5h, the material was discharged and filtered to obtain nicotinic acid modified pyridoxamine phosphate polyether polyol. The hydroxyl value and viscosity (25°C) of this rigid foam polyether polyol were tested to be 374mgKOH / g and 6865MPa·s.

[0027] Example 3 The preparation method of the nicotinic acid modified pyridoxamine polyether polyol comprises the following steps: (1) Preparation of pyridoxamine phosphate: 168 g of pyridoxamine and 168 g of 75 wt.% phosphoric acid aqueous solution were added to a reaction kettle, followed by addition of ethanol, which was dissolved at room temperature, and then heated while maintaining the temperature at 107.5±2.5°C and the pressure at -0.09±0.01 MPa, and vacuum bubbling dehydration was performed for 1.5 h to obtain pyridoxamine phosphate; (2) Preparation of pyridoxamine nicotinate: Nicotinic acid and pyridoxamine phosphate were added in a molar ratio of 1.8:1 into a reactor, and then 97wt.% sulfuric acid with a mass ratio of 0.03% of pyridoxamine phosphate was added, and an esterification reaction was carried out at 220°C. After bubbling dehydration for 1.5 hours, pyridoxamine nicotinate was generated; (3) Polymerization reaction: In a 2L autoclave equipped with a stirrer, a meter, a heating and temperature control device, a cooling device (including an outer jacket and an inner coil) and a pressure sensor, 245g of diethylene glycol, 156g of glycerol, 152g of nicotinate pyridoxamine, 6g of 2,4,6-tris(dimethylaminomethyl)phenol and 9g of N,N-dimethylcyclohexylamine were added, and nitrogen was introduced to test the reactor for leakage. Under the condition that the reactor was well sealed, nitrogen was replaced. After nitrogen replacement, the temperature was raised to 82.5±2.5℃ and the pressure was 0.25±0.15MPa under vacuum, and 275g of ethylene oxide was added dropwise. After the addition was completed, the reaction mixture was aged for 2h; the temperature was continued to be raised to 107.5±2.5℃ and the pressure was 0.25±0.15MPa, and 1016g of ethylene oxide was continued to be added dropwise. After the addition was completed, when the reaction pressure remained basically unchanged, the pressure was increased to 0.3MPa and the reaction mixture was aged for 3h; (4) Post-treatment: The matured polyether was kept at 107.5±2.5°C, and then the pressure was maintained at -0.09±0.01MPa, and nitrogen was bubbled. After bubbling for 2h, the material was discharged and filtered to obtain nicotinic acid modified pyridoxamine phosphate polyether polyol. The hydroxyl value and viscosity (25°C) of this rigid foam polyether polyol were tested to be 358mgKOH / g and 4546MPa·s.

[0028] Comparative Example 1 This comparative example is the same as Example 1, except that this comparative example does not include the preparation process of pyridoxamine nicotinate, that is, the polyether of this comparative example is prepared from step (3) of the example, except that pyridoxamine nicotinate is not included, and the remaining steps and raw materials and the amounts of raw materials are the same as those of the example. The hydroxyl value and viscosity (25°C) of the polyether polyol finally prepared in this comparative example are 378 mgKOH / g and 6008 MPa·s.

[0029] Comparative Example 2 The preparation method of the nicotinic acid modified pyridoxamine polyether polyol comprises the following steps: (1) Preparation of pyridoxamine phosphate: 168 g of pyridoxamine and 130 g of 75 wt.% phosphoric acid aqueous solution were added to a reaction kettle, followed by addition of ethanol and chloroform, dissolved at room temperature, and then heated, maintaining the temperature at 107.5±2.5°C, maintaining the pressure at -0.09±0.01 MPa, and vacuum bubbling dehydration for 1.5 h to obtain pyridoxamine phosphate; (2) Polymerization reaction: In a 2L autoclave equipped with a stirrer, a meter, a heating and temperature control device, a cooling device (including an outer jacket and an inner coil) and a pressure sensor, 150g of liquid sorbitol, 400g of diethylene glycol, 200g of glycerol, 350g of pyridoxamine phosphate and 20g of 2,4,6-tris(dimethylaminomethyl)phenol were added, and nitrogen was filled into the autoclave for leak testing. Under the condition that the autoclave was well sealed, the air was replaced with nitrogen, and then the temperature was raised to 82.5±2.5℃ and the pressure was 0.25±0. 15MPa, add 251g of ethylene oxide and propylene oxide mixture dropwise, mature for 1h after the addition is completed, then raise the temperature in the kettle to 110°C, evacuate and bubble nitrogen to maintain the pressure at -0.09±0.01MPa for 1.5h to remove moisture from the liquid sorbitol; control the temperature to 107.5±2.5°C and the pressure to 0.25±0.15MPa, continue to add 2105g of ethylene oxide and propylene oxide mixture dropwise, and when the reaction pressure remains basically unchanged after the feeding is completed, make up the pressure to 0.2MPa and mature for 2h; (3) Post-treatment: The matured polyether was kept at 107.5±2.5°C, and then the pressure was maintained at -0.09±0.01MPa, and nitrogen was bubbled. After bubbling for 1h, the material was discharged and filtered to obtain nicotinic acid modified pyridoxamine phosphate polyether polyol. The hydroxyl value and viscosity (25°C) of this rigid foam polyether polyol were tested to be 402mgKOH / g and 4658MPa·s.

[0030] The polyether polyols synthesized in Examples 1-3 and Comparative Examples 1-2 are used as raw materials to prepare a composite material, the composite material consisting of A material and B material, A material includes the following raw materials by mass: 100 parts of polyether polyol, 1.5 parts of water, 1 part of PC-8, 2 parts of M8815, 14 parts of cyclopentane, wherein the catalyst PC-8 is a commercially available product of Wanhua Chemical Group Co., Ltd., and the silicone oil M8815 is a commercially available product of Jiangsu Meside Chemical Co., Ltd.; B material is PM200, which is a commercially available product of Wanhua Chemical Group Co., Ltd.; A material and B material are mixed evenly in a mass ratio of 1:1 and then foamed to obtain a rigid foam polyether polyol sample. The rigid foam polyether polyol samples corresponding to each embodiment and comparative example are the same in terms of raw materials, raw material amounts, and steps except that the polyether polyols are different.

[0031] After mixing material A and material B evenly, foaming is performed to verify the oxygen index, compression strength, activity, and pentane miscibility of the foam.

[0032] Oxygen index: the oxygen index in the examples and comparative examples was tested according to GB20286-2006 standard; Compression strength: the compression strength in the examples and comparative examples was tested according to GB / T8813-2008 standard; Activity: the time taken from starting to drawing after material A and material B are fully stirred, the shorter the time, the higher the activity; Pentane miscibility: the number of n-pentane or cyclopentane that is completely miscible with 1 part of polyether polyol, the performance test results are shown in Table 1.

[0033] Table 1 Rigid polyurethane foam performance test table

[0034] As shown in Table 1, by comparing Examples 1-3 and Comparative Examples 1-2, the performance of various aspects after adding nicotinic acid pyridoxamine ester is significantly improved compared with the performance of various aspects without adding nicotinic acid pyridoxamine ester, because: nicotinic acid pyridoxamine ester contains nitrogen and phosphorus elements, which improves the oxygen index of downstream foam, thereby improving the flame retardancy of foam; and nicotinic acid pyridoxamine ester and foaming agent cyclopentane both contain cyclic structures, and due to the characteristics of similar miscibility, the mutual solubility of pentane is improved; secondly, the presence of pyridine structure in nicotinic acid pyridoxamine ester improves the compressive strength of rigid polyurethane foam. As can be seen from Comparative Example 2, after using pyridoxamine phosphate as an initiator to replace nicotinic acid pyridoxamine ester, the polyether polyol is synthesized. Due to the absence of ester groups in the system, the mutual solubility of polyether polyol pentane is poor, and nicotinic acid modification is not performed, the pyridine structure content is low, and the product activity is low, which leads to a significant reduction in the compressive strength and flame retardancy of rigid polyurethane foam.

[0035] It can be seen from the above examples that the nicotinic acid modified pyridoxamine polyether polyol of the present invention is composed of nicotinic acid pyridoxamine ester composed of nitrogen and phosphorus elements and a cyclic structure, so that the polyether polyol macromolecular chain contains rigid chain groups, thereby giving the product better compression strength and flame retardancy.

Claims

1. A method for preparing a nicotinic acid modified pyridoxamine polyether polyol, characterized in that: Pyridoxamine and phosphoric acid aqueous solution are reacted to convert into pyridoxamine phosphate, nicotinic acid and pyridoxamine phosphate are esterified under the action of sulfuric acid as a catalyst, and nicotinic acid pyridoxamine ester is obtained after dehydration. Subsequently, nicotinic acid pyridoxamine ester and liquid small molecule alcohol are used as initiators, and polymerization reaction is carried out with alkylene oxide under the action of alkaline catalyst. After post-treatment, nicotinic acid modified pyridoxamine phosphate polyether polyol is obtained.

2. The method for preparing the nicotinic acid modified pyridoxamine polyether polyol according to claim 1, characterized in that: The specific synthesis process of the pyridoxamine phosphate is as follows: pyridoxamine and 75wt.% phosphoric acid aqueous solution in a mass ratio of (1-1.68):1 are added into a reaction kettle, and then a solvent is added, dissolved at room temperature, the temperature is maintained at 105-110°C, the pressure is maintained at -0.08-0.1MPa, and vacuum bubbling dehydration is performed to obtain pyridoxamine phosphate.

3. The method for preparing the nicotinic acid modified pyridoxamine polyether polyol according to claim 2, characterized in that: The solvent is one or two of ethanol and chloroform.

4. The method for preparing the nicotinic acid modified pyridoxamine polyether polyol according to claim 1, characterized in that: The specific synthesis process of the nicotinic acid pyridoxamine ester is as follows: nicotinic acid and pyridoxamine phosphate are added in a molar ratio of (1-1.8):1 into a reaction kettle, and then 97wt.% sulfuric acid is added, and an esterification reaction is carried out at 200-220°C, and nicotinic acid pyridoxamine ester is generated after dehydration.

5. The method for preparing the nicotinic acid modified pyridoxamine polyether polyol according to claim 1, characterized in that: The specific synthesis process of the polymerization reaction is as follows: nicotinate pyridoxamine ester, liquid small molecule alcohol and alkaline catalyst are added into a reaction kettle, nitrogen replacement is followed by vacuum heating, the temperature is maintained at 80-85°C and the pressure is 0.1-0.4MPa, alkylene oxide is added dropwise, and the reaction is matured for 1-2h after the addition is completed; the temperature is continued to be increased, the temperature is controlled at 105-110°C and the pressure is 0.1-0.4MPa, and the alkylene oxide is continued to be added dropwise, and when the reaction pressure remains substantially unchanged after the feeding is completed, the pressure is supplemented to 0.2-0.3MPa, and the reaction is matured for 2-3h.

6. The method for preparing the nicotinic acid modified pyridoxamine polyether polyol according to claim 1, characterized in that: The post-treatment process is as follows: the system after the polymerization reaction is kept warm at 105-110°C, and then the pressure is maintained at -0.08-0.1MPa while nitrogen is bubbled. After bubbling for 1-2h, nicotinic acid-modified pyridoxamine phosphate polyether polyol is obtained by filtration.

7. The method for preparing the nicotinic acid modified pyridoxamine polyether polyol according to claim 1, characterized in that: The liquid small molecule alcohol is two or three of diethylene glycol, liquid sorbitol and glycerol, and the alkylene oxide is one or two of propylene oxide and ethylene oxide.

8. The method for preparing nicotinic acid modified pyridoxamine polyether polyol according to claim 1, characterized in that: The total amount of the nicotinate pyridoxamine ester and the liquid small molecule alcohol added is 42.5-45.5wt.% of the total amount of the alkylene oxide added.

9. The method for preparing nicotinic acid modified pyridoxamine polyether polyol according to claim 1, characterized in that: The alkaline catalyst is one or two of 2,4,6-tris(dimethylaminomethyl)phenol, N,N-dimethylcyclohexylamine and dimethylamine.

10. A nicotinic acid modified pyridoxamine polyether polyol, characterized in that: The polyol is prepared by the preparation method of nicotinic acid modified pyridoxamine polyether polyol according to any one of claims 1 to 9.

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