Preparation method of polyether polyol for flatulence slow-rebound foam

Abstract

The invention discloses a preparation method of polyether polyol for flatulence slow-rebound foam, and relates to the technical field of polyether polyol synthesis, and the preparation method comprises the following steps: S1, preparing an initiator: mixing glycerol and potassium hydroxide for reaction, dehydrating for 1-3 hours at 110-120 DEG C under vacuum condition to obtain potassium glycerol with the water content of less than or equal to 0.05%, and filtering to obtain the initiator; wherein the mass ratio of potassium hydroxide to glycerol is 1: (13-20); s2, carrying out two-stage polymerization reaction; and S3, refining treatment. In the middle stage of the reaction, the feeding proportion of the epoxide is changed, the proportion of the ethylene oxide is increased, and a non-ethylene oxide end-capping process is adopted to prepare the swellable slow-rebound polyether polyol. When the process is used for producing polyether, the reaction speed of epoxypropane in the early stage of reaction is higher, meanwhile, the situation that the production period is prolonged due to intermediate curing is avoided, and the production efficiency is improved. The polyether applying the process has better performance during foaming, has stronger adaptability to a formula, and avoids wettability reduction of foam and foam shrinkage during foaming caused by ethylene oxide end capping.

Description

Technical Field

[0001] This invention belongs to the field of polyether polyol synthesis technology, and specifically relates to a method for preparing polyether polyols for inflatable slow-rebound foam. Background Technology

[0002] Polyurethane (PU) is produced through the addition polymerization of polyols and polyisocyanates. Despite its relatively short history, PU has become one of the most dynamic polymer materials due to its strong designability. By adjusting the functionality and ratio of polyols and isocyanates, PU products with diverse forms and functions can be prepared, including elastomers, adhesives, coatings, fibers, and foams. Among these, polyurethane foam, made by adding blowing agents and foam leveling agents to the base components, is a foam plastic with characteristics such as low density, easy processing, and a wide range of performance control, making it the largest downstream market for PU. Polyether polyols are the largest raw material for polyurethane, and approximately 80% of their downstream consumption is in the polyurethane industry, demonstrating a strong synergy between the two. Furthermore, the composition of polyether polyols typically has a decisive impact on the performance of polyurethane, primarily depending on the type of initiating alcohol, the epoxide ratio, and the polymerization feedstock process.

[0003] To increase the activity of polyether polyols and reduce foam curing time, the polyether polyols used in commercially available slow-rebound foams generally employ an ethylene oxide-terminated process. This means that after copolymerization, ethylene oxide is added separately after curing or degassing. While this solves the polyether activity problem, this process has the following significant drawbacks: the intermediate curing process lengthens the production time and reduces efficiency; the accumulation of large amounts of EO monomers at the polyether chain ends leads to significant foam shrinkage; and it has been reported that DMC cannot catalyze ethylene oxide polymerization alone, thus limiting the application of bimetallic catalysis (DMC), while alkali metal catalysis faces difficulties in preparing high molecular weight and low unsaturation polyethers.

[0004] After polymerization, the main components of the crude ether at this stage are polyether polyol, low-boiling-point substances, and potassium ions. Excessive potassium ion content in the polyether polyol can have several adverse effects: during polyurethane foaming, potassium ions promote the formation of rigid and cross-linked urea esters and biuret groups, affecting the flowability of the mixture, accelerating foam curing, and causing the polyurethane foam products to harden and lose elasticity. Simultaneously, the heat generated during foaming cannot be dissipated in time, leading to foam core burning. Therefore, the crude ether must be refined to obtain a qualified polyether product before further use. In the production process of flexible foam polyether polyol, the phosphoric acid plus adsorbent (such as magnesium silicate) method is the most widely used and mature. Generally, water is added first to reduce the viscosity of the system, then phosphoric acid is added for neutralization, and preferably magnesium silicate is added last for adsorption. After dehydration, potassium dihydrogen phosphate is precipitated, filtered off, and qualified polyether is produced. This method performs well in the refining of ordinary flexible foam, forming larger phosphate particles and resulting in faster filtration. However, due to the higher proportion of ethylene oxide in the raw materials, the polarity of the slow-rebound polyether polyol is greater than that of ordinary flexible foam, resulting in poor stability during dehydration and salt formation. If the dehydration rate is too fast, the salt particles are small and can pass through the filter pores and mix into the product, often leading to excessive potassium content or decreased transparency, seriously affecting product quality. Furthermore, although phosphoric acid is a tribasic acid, it can only be calculated as a monobasic acid during neutralization, and requires the addition of magnesium silicate for further adsorption. This results in a large amount of refining material, which is not only costly but also generates a significant amount of solid waste. When using polycarboxylic acids for neutralization, the molar amount of polycarboxylic acid used is smaller, and the resulting potassium polycarboxylic acid salt has a greater polarity difference from the polyether, resulting in larger particle sizes that are easier to precipitate and filter.

[0005] No effective solutions have yet been proposed to address the problems in the relevant technologies.

[0006] Therefore, in order to solve the above problems, the present invention provides a method for preparing polyether polyols for inflatable slow-rebound foam. Summary of the Invention

[0007] In order to overcome the above-mentioned technical problems, the purpose of this invention is to provide a method for preparing polyether polyols for inflatable slow-rebound foam.

[0008] The objective of this invention can be achieved through the following technical solutions: A method for preparing a polyether polyol for inflatable slow-rebound foam includes the following steps: S1. Preparation of initiator: Glycerol and potassium hydroxide are mixed and reacted, and then dehydrated under vacuum at 110-120℃ for 1-3 hours to obtain potassium glycerol with a water content ≤0.05%, wherein the mass ratio of potassium hydroxide to glycerol is 1:13-20. S2, Two-stage polymerization reaction: First half of polymerization: Control the temperature of the reactor at 115-125℃ and the pressure at 0.02-0.5MPa, add epoxide to the potassium glycerol prepared in step S1, wherein ethylene oxide accounts for 55-70% of the total mass of the epoxide, and a polymerization reaction occurs; Second half of polymerization: Adjust the reactor temperature to 120-130℃ and the pressure to <0.5MPa, and continue to add epoxides to the reaction system. Ethylene oxide accounts for 70-90% of the total mass of the epoxides, and polymerization continues. Maturation and Removal: After feeding is complete, maintain the above reaction temperature for 0.5-1.5 hours until the pressure inside the reactor no longer decreases. Then, reduce the reactor temperature to 100℃ and remove unreacted monomers and small molecule impurities under a pressure < -0.090MPa to obtain crude ether. S3. Refining treatment: Mix the polycarboxylic acid, water and the crude ether, and neutralize the mixture at 75-80°C for 1-1.5 hours. Then, dehydrate the mixture at 120-135°C and a pressure of <-0.090MPa with nitrogen bubbling assistance for at least 30 minutes. Filter to remove solid salts to obtain polyether polyol.

[0009] As a preferred embodiment of the present invention, in step S1, the dehydration process is assisted by nitrogen bubbling, and the mass ratio of glycerol to the total epoxide in the subsequent polymerization reaction is 1:48-55.

[0010] As a preferred embodiment of the present invention, in step S2, the amount of epoxide used in the latter half of the polymerization accounts for 55-65% of the total amount of epoxide used in the polymerization process.

[0011] As a preferred technical solution of the present invention, by controlling the weight ratio of epoxide to potassium glycerol, the molecular weight of the prepared polyether polyol is designed to be 4500-5100 g / mol.

[0012] As a preferred embodiment of the present invention, in step S3, the polycarboxylic acid is selected from one or more of glutaric acid, adipic acid, pimelic acid, octanoic acid, azelaic acid, sebacic acid, brassic acid, and citric acid.

[0013] As a preferred embodiment of the present invention, in step S3, the molar ratio of the carboxyl group of the polycarboxylic acid to the potassium ion in the crude ether is 0.5-0.9, and the weight ratio of water to crude ether is 0.05-0.10.

[0014] As a preferred embodiment of the present invention, in step S3, the dehydration time is 1-4 hours, and the particle size of the precipitated solid salt is controlled by adjusting the dehydration speed.

[0015] As a preferred technical solution of the present invention, the final polyether polyol meets the following requirements: pH value of 5-7, acid value of less than 0.05 mg KOH / g, potassium ion content of less than 5 ppm, and water content of less than 0.05%.

[0016] Compared with the prior art, the present invention has the following beneficial effects: 1. In this invention, the feed ratio of epoxide is changed during the middle stage of the reaction to increase the proportion of ethylene oxide, and a non-ethylene oxide end-capping process is used to prepare a slow-rebound polyether polyol. When using this process to produce polyether, the reaction rate of propylene oxide is faster in the early stage of the reaction, while avoiding the increased production cycle caused by intermediate ripening, thus improving production efficiency. Polyether produced using this process performs better during foaming, has stronger adaptability to formulations, and avoids the decrease in foam wettability and foam shrinkage during foaming caused by ethylene oxide end-capping.

[0017] 2. In this invention, polycarboxylic acids are used instead of phosphoric acid and adsorbents, resulting in fewer types of materials used in the post-treatment process, lower material consumption, easier control, a more stable salt formation process, less solid waste generated, and better filtration effect. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a system diagram of the present invention; Figure 2 The images show a comparison of the appearance of the polyether foam prepared using the present invention with that of commercially available polyether foam (from left to right in the images: commercially available polyether foam, P1, P2, and P3). Detailed Implementation

[0020] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby providing a clearer and more explicit definition of the scope of protection of the present invention: Please see Figure 1 A method for preparing polyether polyols for inflatable slow-rebound foam according to an embodiment of the present invention includes the following steps: S1. Preparation of initiator: Glycerol and potassium hydroxide are mixed and reacted, and then dehydrated under vacuum at 110-120℃ for 1-3 hours to obtain potassium glycerol with a water content ≤0.05%. The mass ratio of potassium hydroxide to glycerol is 1:13-20. The dehydration process is assisted by nitrogen bubbling. The mass ratio of glycerol to the total epoxide in the subsequent polymerization reaction is 1:48-55. S2, Two-stage polymerization reaction: First half of polymerization: Control the temperature of the reactor at 115-125℃ and the pressure at 0.02-0.5MPa, add epoxide to the potassium glycerol prepared in step S1, wherein ethylene oxide accounts for 55-70% of the total mass of the epoxide, and a polymerization reaction occurs; Second half of polymerization: Adjust the reactor temperature to 120-130℃ and the pressure to <0.5MPa, and continue to add epoxides to the reaction system. Ethylene oxide accounts for 70-90% of the total mass of the epoxides. Continue polymerization, and the amount of epoxides used accounts for 55-65% of the total amount of epoxides used in the polymerization process. Maturation and Removal: After feeding is complete, maintain the above reaction temperature for 0.5-1.5 hours until the pressure inside the reactor no longer decreases. Then, reduce the reactor temperature to 100℃ and remove unreacted monomers and small molecule impurities under a pressure < -0.090MPa to obtain crude ether. S3. Refining treatment: Mix polycarboxylic acid, water and crude ether, and neutralize at 75-80℃ for 1-1.5 hours. Then, dehydrate with nitrogen bubbling assistance at 120-135℃ and pressure <-0.090MPa for at least 30 minutes. Filter to remove solid salts to obtain polyether polyol.

[0021] Specifically, by controlling the weight ratio of epoxide to potassium glycerol, the molecular weight of the prepared polyether polyol was designed to be 4500-5100 g / mol.

[0022] Specifically, in step S3, the polycarboxylic acid is selected from one or more of the following: glutaric acid, adipic acid, pimelic acid, octanoic acid, azelaic acid, sebacic acid, brassic acid, and citric acid.

[0023] Specifically, in step S3, the molar ratio of the carboxyl group of the polycarboxylic acid to the potassium ion in the crude ether is 0.5-0.9, and the weight ratio of water to crude ether is 0.05-0.10.

[0024] Specifically, in step S3, the dehydration time is 1-4 hours, and the particle size of the precipitated solid salt is controlled by adjusting the dehydration speed.

[0025] Specifically, the final polyether polyol meets the following requirements: pH value of 5-7, acid value of less than 0.05 mg KOH / g, potassium ion content of less than 5 ppm, and water content of less than 0.05%. Example 1

[0026] At room temperature, 93.6 g of glycerol and 7.02 g of potassium hydroxide were placed in a 10 L high-pressure reactor. Stirring was started (300 rpm), and the mixture was purged with nitrogen three times. The reactor was then heated to 100 °C and reacted for 20 minutes. The mixture was then heated to 120 °C and dehydrated at -0.095 MPa for 1.5 hours with nitrogen bubbling assistance. Nitrogen was added to the reactor until the pressure reached 0.01 MPa. The temperature was raised to 115 °C, and the stirring speed was increased to 300 rpm. Epoxides were added dropwise for the first half of the polymerization reaction, including 1740 g of ethylene oxide and 900 g of propylene oxide. After the initial feeding was complete, the relative feed rate of the epoxides was changed to initiate the second half of the polymerization reaction. The temperature was raised to 125 °C, and the remaining 1928 g of ethylene oxide and 322 g of propylene oxide were added. After all feed is completed, maintain the reaction temperature at 125℃ for 1 hour. Once the pressure stops decreasing, cool down to 100℃, reduce the stirring speed to 300 rpm, turn on the vacuum pump to reduce the pressure to -0.095 MPa, and degas for 20 minutes.

[0027] 10.1 g of pimelic acid and 250 g of water were added to a refining vessel and heated to 70 °C. Then, crude ether was added, and the mixture was stirred at 80 °C for 60 minutes. The mixture was then dehydrated at 125 °C under a pressure below -0.092 MPa for 1.5 hours with nitrogen bubbling assistance. The solution was filtered through a G3 funnel to obtain a clear, colorless liquid polyether polyol P1. Example 2

[0028] At room temperature, 94.0 g of glycerol and 7.04 g of potassium hydroxide were placed in a 10 L high-pressure reactor. Stirring was started (300 rpm), and after purging with nitrogen three times, the mixture was heated to 100 °C and reacted for 20 minutes. Then, the mixture was heated to 120 °C and dehydrated at -0.095 MPa for 1.5 hours with nitrogen bubbling assistance. Nitrogen was added to the reactor until the pressure reached 0.01 MPa. The temperature was raised to 120 °C, and the stirring speed was increased to 400 rpm. Epoxides were added dropwise for the first half of the polymerization reaction, including 1808 g of ethylene oxide and 940 g of propylene oxide. After the initial feeding was complete, the relative feed rate of the epoxides was changed to initiate the second half of the polymerization reaction. The temperature was raised to 125 °C, and the remaining 2024 g of ethylene oxide and 336 g of propylene oxide were added. After all feed is completed, maintain the reaction temperature at 125℃ for 50 minutes. At this point, the pressure in the reactor will no longer decrease. Cool down to 100℃, reduce the stirring speed to 300 rpm, turn on the vacuum pump to reduce the pressure to -0.095 MPa, and degas for 20 minutes.

[0029] Add 9.12 g of adipic acid and 260 g of water to the crude ether, stir at 80 °C for 80 minutes, then dehydrate at 125 °C and a pressure below -0.092 MPa for 1.5 hours with nitrogen bubbling assistance. Filter through a G3 funnel to obtain a clear, colorless liquid polyether polyol P2. Example 3

[0030] At room temperature, 116g of glycerol and 8.70g of potassium hydroxide were placed in a 10L high-pressure reactor. Stirring was started (300rpm), and after purging with nitrogen three times, the mixture was heated to 100℃ and reacted for 20 minutes. Then, the mixture was heated to 120℃, and the stirring speed was increased to 500rpm. Dehydration was carried out at -0.095MPa for 2 hours with nitrogen bubbling assistance. Nitrogen was added to the reactor until the pressure reached 0.01MPa. Epoxides were added dropwise to the reactor for the first half of the polymerization reaction, including 2792g of ethylene oxide and 1201g of propylene oxide. After the feed was complete, the temperature was raised to 130℃, and the relative feed rate of the epoxides was changed to carry out the second half of the polymerization reaction. The temperature was raised to 130℃, and the remaining 1866g of ethylene oxide and 211g of propylene oxide were added. After all feed is completed, maintain the reaction temperature at 130℃ for 1 hour. Once the pressure stops decreasing, cool down to 100℃, reduce the stirring speed to 300 rpm, turn on the vacuum pump to reduce the pressure to -0.095 MPa, and degas for 20 minutes.

[0031] 2.94 g adipic acid, 10.0 g octanoic acid, and 310 g water were added to a refining vessel and heated to 70°C. Crude ether was then added, and the mixture was stirred at 80°C for 60 minutes. Dehydration was then carried out at 125°C under a pressure below -0.092 MPa for 2 hours, assisted by nitrogen bubbling. The solution was filtered through a G3 funnel to obtain a clear, colorless liquid polyether polyol P3. Example 4

[0032] At room temperature, 114g of glycerol and 8.70g of potassium hydroxide were placed in a 10L high-pressure reactor. Stirring was started (300rpm), and after purging with nitrogen three times, the mixture was heated to 100℃ and reacted for 20 minutes. Then, the mixture was heated to 120℃, and the stirring speed was increased to 500rpm. Dehydration was carried out at -0.095MPa for 2 hours with nitrogen bubbling assistance. Nitrogen was added to the reactor until the pressure reached 0.01MPa. Epoxides were added dropwise to the reactor for the first half of the polymerization reaction, including 2780g of ethylene oxide and 1190g of propylene oxide. After the feed was complete, the temperature was raised to 130℃, and the relative feed rate of the epoxides was changed to carry out the second half of the polymerization reaction. The temperature was raised to 130℃, and the remaining 1866g of ethylene oxide and 211g of propylene oxide were added. After all feed is completed, maintain the reaction temperature at 130℃ for 1 hour. Once the pressure stops decreasing, cool down to 100℃, reduce the stirring speed to 300 rpm, turn on the vacuum pump to reduce the pressure to -0.095 MPa, and degas for 20 minutes.

[0033] 12.4 g of pimelic acid and 310 g of water were added to a refining vessel and heated to 70 °C. Then, crude ether was added, and the mixture was stirred at 80 °C for 60 minutes. The mixture was then dehydrated at 125 °C under a pressure below -0.092 MPa for 2 hours, assisted by nitrogen bubbling. The solution was filtered through a G3 funnel to obtain a clear, colorless liquid polyether polyol P4. Example 5

[0034] At room temperature, 57.0 g of glycerol and 8.70 g of potassium hydroxide were placed in a 5 L high-pressure reactor. Stirring was started (300 rpm), and after purging with nitrogen three times, the mixture was heated to 100 °C and reacted for 20 minutes. Then, the mixture was heated to 120 °C, and the stirring speed was increased to 500 rpm. Dehydration was carried out at -0.095 MPa for 2.5 hours with nitrogen bubbling assistance. Nitrogen was added to the reactor until the pressure reached 0.01 MPa. Epoxides (1390 g of ethylene oxide and 595 g of propylene oxide) were added dropwise to initiate the first half of the polymerization reaction. After the feed was complete, the temperature was raised to 130 °C, and the relative feed rate of the epoxides was changed to initiate the second half of the polymerization reaction. The temperature was raised to 130 °C, and 933 g of ethylene oxide and 105 g of propylene oxide were added. After all feed is completed, maintain the reaction temperature at 130℃ for 1 hour. Once the pressure stops decreasing, cool down to 100℃, reduce the stirring speed to 300 rpm, turn on the vacuum pump to reduce the pressure to -0.095 MPa, and degas for 20 minutes.

[0035] 4.02 g pimelic acid, 2.52 g octanoic acid, and 150 g water were added to a refining vessel and heated to 80 °C. Crude ether was then added, and the mixture was stirred at 80 °C for 60 minutes. Dehydration was then carried out at 125 °C under a pressure below -0.092 MPa for 2 hours, assisted by nitrogen bubbling. The solution was filtered through a G3 funnel to obtain a clear, colorless liquid polyether polyol P5. Example 6

[0036] At room temperature, 54.0 g of glycerol and 8.70 g of potassium hydroxide were placed in a 5 L high-pressure reactor. Stirring was started (300 rpm), and after purging with nitrogen three times, the mixture was heated to 100 °C and reacted for 20 minutes. Then, the mixture was heated to 120 °C, and the stirring speed was increased to 500 rpm. Dehydration was carried out at -0.095 MPa for 2.5 hours with nitrogen bubbling assistance. Nitrogen was added to the reactor until the pressure reached 0.01 MPa. Epoxides (1300 g of ethylene oxide and 575 g of propylene oxide) were added dropwise to initiate the first half of the polymerization reaction. After the feed was complete, the temperature was raised to 130 °C, and the relative feed rate of the epoxides was changed to initiate the second half of the polymerization reaction. The temperature was raised to 130 °C, and 930 g of ethylene oxide and 106 g of propylene oxide were added. After all feed is completed, maintain the reaction temperature at 130℃ for 1 hour. Once the pressure stops decreasing, cool down to 100℃, reduce the stirring speed to 300 rpm, turn on the vacuum pump to reduce the pressure to -0.095 MPa, and degas for 20 minutes.

[0037] 7.89 g of sebacic acid and 150 g of water were added to a refining vessel and heated to 80 °C. Then, crude ether was added, and the mixture was stirred at 80 °C for 60 minutes. The mixture was then dehydrated at 125 °C under a pressure below -0.092 MPa for 2 hours, assisted by nitrogen bubbling. The solution was filtered through a G3 funnel to obtain a clear, colorless liquid polyether polyol P6.

[0038] The following is a summary of Examples 1-6: Table 1: Main test indicators of polyether polyols P1, P2, P3, P4, P5 and P6

[0039] Table 2. Time required for filtration with different filtrate volumes using the phosphoric acid + magnesium silicate and pimelic acid methods

[0040] Table 3. Comparison of foaming activity and foam rebound time of P1, P2, and P3 with commercially available polyethers.

[0041] As shown in Table 1, P1, P2, P3, P4, P5 and P6 all have molecular weights that meet the design requirements (4500-5100 g / mol), viscosity that meets the downstream foaming requirements, narrow molecular weight distribution, and pH, acid value and potassium ion content that are all within the industry's required range.

[0042] Table 2 compares the filtration speeds of the same polyether when using G3 funnel filtration in the phosphoric acid + magnesium silicate and polycarboxylic acid refining stages. When using phosphoric acid + magnesium silicate refining, the filtration speed slows down significantly as the filter residue accumulates due to factors such as smaller salt particle size. Therefore, the total filtration time is significantly longer, i.e., the filtration speed is slower.

[0043] Table 3 compares the activity of P1, P2, P3 and commercially available polyethers during foaming, as well as the foam density and rebound time. The polyether prepared by the method described in this scheme has an activity comparable to or better than that of commercially available polyethers. In addition, other properties of the foam can be adjusted by changing the relative feed rate, the ratio of ethylene oxide to propylene oxide, molecular weight, etc.

[0044] Depend on Figure 2 It can be seen that P1, P2 and P3 under the same formula have basically the same appearance as commercially available polyether foam, meeting the conditions for practical application.

[0045] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0046] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a polyether polyol for inflatable slow-rebound foam, characterized in that, Includes the following steps: S1. Preparation of initiator: Glycerol and potassium hydroxide are mixed and reacted, and then dehydrated under vacuum at 110-120℃ for 1-3 hours to obtain potassium glycerol with a water content ≤0.05%, wherein the mass ratio of potassium hydroxide to glycerol is 1:13-20. S2, Two-stage polymerization reaction: First half of polymerization: Control the temperature of the reactor at 115-125℃ and the pressure at 0.02-0.5MPa, add epoxide to the potassium glycerol prepared in step S1, wherein ethylene oxide accounts for 55-70% of the total mass of the epoxide, and a polymerization reaction occurs; Second half of polymerization: Adjust the reactor temperature to 120-130℃ and the pressure to <0.5MPa, and continue to add epoxides to the reaction system. Ethylene oxide accounts for 70-90% of the total mass of the epoxides, and polymerization continues. Maturation and Removal: After feeding is complete, maintain the above reaction temperature for 0.5-1.5 hours until the pressure inside the reactor no longer decreases. Then, reduce the reactor temperature to 100℃ and remove unreacted monomers and small molecule impurities under a pressure < -0.090MPa to obtain crude ether. S3. Refining treatment: Mix the polycarboxylic acid, water and the crude ether, and neutralize the mixture at 75-80°C for 1-1.5 hours. Then, dehydrate the mixture at 120-135°C and a pressure of <-0.090MPa with nitrogen bubbling assistance for at least 30 minutes. Filter to remove solid salts to obtain polyether polyol.

2. The method for preparing polyether polyol for inflatable slow-rebound foam according to claim 1, characterized in that, In step S1, the dehydration process is assisted by nitrogen bubbling, and the mass ratio of glycerol to the total epoxide in the subsequent polymerization reaction is 1:48-55.

3. The method for preparing polyether polyol for inflatable slow-rebound foam according to claim 1, characterized in that, In step S2, the amount of epoxide used in the latter half of the polymerization accounts for 55-65% of the total amount of epoxide used in the polymerization process.

4. The method for preparing polyether polyol for inflatable slow-rebound foam according to claim 1, characterized in that, By controlling the weight ratio of epoxide to potassium glycerol, the designed molecular weight of the prepared polyether polyol was 4500-5100 g / mol.

5. The method for preparing polyether polyol for inflatable slow-rebound foam according to claim 1, characterized in that, In step S3, the polycarboxylic acid is selected from one or more of the following: glutaric acid, adipic acid, pimelic acid, octanoic acid, azelaic acid, sebacic acid, brassic acid, and citric acid.

6. The method for preparing polyether polyol for inflatable slow-rebound foam according to claim 1, characterized in that, In step S3, the molar ratio of the carboxyl group of the polycarboxylic acid to the potassium ion in the crude ether is 0.5-0.9, and the weight ratio of water to crude ether is 0.05-0.

10.

7. The method for preparing polyether polyol for inflatable slow-rebound foam according to claim 1, characterized in that, In step S3, the dehydration time is 1-4 hours, and the particle size of the precipitated solid salt is controlled by adjusting the dehydration speed.

8. The method for preparing polyether polyol for inflatable slow-rebound foam according to claim 1, characterized in that, The final polyether polyol meets the following requirements: pH value of 5-7, acid value of less than 0.05 mg KOH / g, potassium ion content of less than 5 ppm, and water content of less than 0.05%.

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