A process for the extraction of polyether polyols from polyurethane soft foam alcoholysis products and the polyether polyols obtained and uses

Abstract

The present application provides a method for extracting polyether polyol from polyurethane soft foam alcoholysis product and the prepared polyether polyol. The purification method is divided into two steps: 1) adjusting the pH value of the soft foam sponge alcoholysis product to moderate acidity using an aqueous solution of inorganic acid; 2) adding a demulsifier, stirring and then separating the organic phase; 3) eluting using an organic polar solvent, and then obtaining pure soft foam polyether polyol after removing the solvent by rotary evaporation. The soft foam polyether polyol produced by the present application has high purity, low metal ion content, moderate viscosity and hydroxyl value, can produce soft foam sponge again, has excellent performance, low cost, and is very suitable for industrial application.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of polyurethane flexible foam degradation and recycling, and particularly relates to a method for extracting polyether polyol from polyurethane flexible foam alcoholysis products and the obtained polyether polyol and use. TECHNICAL BACKGROUND

[0002] At present, waste flexible foam sponge is mainly landfilled or burned for power generation, which is not environmentally friendly and economical. At present, the circular economy is in the ascendant, and people fully realize that garbage is a resource, which is a valuable renewable and recyclable resource misplaced. Therefore, many research institutes and industrial circles are studying the degradation and closed-loop utilization of polyurethane flexible foam to reduce the carbon footprint and carbon emissions of polyurethane materials. For example, patents CN109320764A, CN103012838A, CN102796279A, CN107286369A, US2019359788A1.

[0003] As reported in the above patents, the product after degradation of the polyurethane flexible foam is a mixture containing the original soft foam polyether polyol, aromatic amine, small fragments of the sponge that have not been completely degraded, catalyst, metal ions, and a large amount of degradation agent, etc. These degradation products have poor quality, high cost, insufficient application performance, and limited application. In fact, the real renewable, economically effective, and high-value closed-loop utilization of soft foam polyether polyol has not been achieved.

[0004] In order to solve the above-mentioned major technical problems, the present application develops a method for extracting polyether polyol from polyurethane flexible foam alcoholysis products and the prepared polyether polyol. SUMMARY

[0005] The purpose of the present application is to provide a method for extracting polyether polyol from polyurethane flexible foam alcoholysis products, and the obtained soft foam polyether polyol has high purity, low metal ion content, moderate viscosity and hydroxyl value, can be used to produce soft foam sponge again, has excellent performance, low cost, and is very valuable for industrial application.

[0006] In order to achieve the above-mentioned application purposes, the present application adopts the following technical solutions:

[0007] A method for extracting polyether polyol from polyurethane flexible foam alcoholysis products, comprising the following steps:

[0008] S1, pH adjustment stage: using an aqueous solution of inorganic acid to adjust the pH value of the flexible foam sponge alcoholysis product to moderate acidity to form a mixed emulsion.

[0009] S2, demulsification and phase separation: adding a demulsifier to the mixed emulsion formed in S1 at room temperature, stirring and then standing for phase separation to obtain an organic phase.

[0010] S3, extraction of polyether polyol: using an organic solvent to elute the organic phase obtained in S2, removing the organic solvent by rotary evaporation to obtain a polyether polyol.

[0011] The polyurethane soft foam alcoholysis product used in the present application refers to a mixture obtained by degrading polyurethane soft foam using a binary or ternary small molecule polyol as an alcoholysis agent and a metal hydroxide or peroxide or organometallic compound as a catalyst. The alcoholysis process is described in detail in patents CN 10539985 A and CN 107955206 A, which can be referred to.

[0012] The polyurethane soft foam alcoholysis product of the present application comprises the following components (mass ratio): soft foam polyol content 60-70wt%; TDA content 15-25wt%, alcoholysis agent content 10-15wt%, and macromolecular structure impurity content 2-5wt%.

[0013] The mixture obtained after degrading the polyurethane soft foam contains degraded intermediates, which are a class of macromolecular structure impurities with a molecular weight of about 300-1000. This type of structure contains hydroxyl and alkyl groups, and is therefore amphiphilic. In the process of oil-water phase separation, it tends to aggregate on the interface between the water and oil phases, resulting in incomplete phase separation. In the present application, based on the design selection of molecular structure containing epoxy and hydroxyl groups, a hydrophilic demulsifier is added, and the epoxy type structure, polymer and alkyl carbon chain number are optimized, on the one hand, to make the oil-water two-phase separation more thorough, and on the other hand, to change the surface properties of the above-mentioned degraded intermediates, making them more hydrophilic, so as to enter the water phase, and then remove the polyether polyol with high purity from the organic phase.

[0014] In the present application, the inorganic acid can be one or more of nitric acid, phosphoric acid, sulfuric acid and hydrochloric acid, preferably nitric acid and hydrochloric acid, and most preferably hydrochloric acid.

[0015] In the present application, the concentration of the aqueous inorganic acid solution is 5-36.5wt%, preferably 10-20wt%, and most preferably 10-15wt%.

[0016] In the present application, it is required that the aqueous inorganic acid solution adjusts the pH value of the alcoholysis product to be between 1-6, preferably between 1-4, and most preferably between 2-3.

[0017] In the present application, the demulsifier used is a polyoxyethylene polyoxypropylene alkyl alcohol ether, with an epoxy ethylene polymerization degree of 6-10, an epoxy propylene polymerization degree of 10-15, and an alkyl carbon chain number of 12-18; preferably an epoxy ethylene polymerization degree of 8-10, an epoxy propylene polymerization degree of 10-12, and an alkyl carbon chain number of 15-18.

[0018] In the present application, the addition amount of polyoxyethylene polyoxypropylene alkyl alcohol ether is 1-3 wt% of the mass of the mixed emulsion in S1, preferably 1.5-2.5 wt%.

[0019] In the present application, after adding the demulsifier in the mixed emulsion, the time for phase separation after stirring is 0.5-2 h, preferably 0.5-1.5 h, more preferably 0.5-1.0 h.

[0020] In the present application, the polar solvent used includes one or a mixture of ethyl acetate, butyl acetate, dichloromethane, trichloromethane, acetone, benzene, chlorobenzene, dichlorobenzene, preferably one or a mixture of ethyl acetate, dichlorobenzene, dichloromethane, most preferably dichloromethane.

[0021] The use amount of the polar solvent is 50-70 wt% of the mass of the mixed emulsion in S1, preferably 55-65 wt%.

[0022] In the present application, the removal method of the polar solvent includes room temperature evaporation, atmospheric distillation and rotary evaporation, preferably room temperature evaporation and reduced pressure distillation, most preferably rotary evaporation.

[0023] Preferably, the rotary evaporation temperature is 15-35℃, preferably 20-25℃, the absolute pressure is 2-10 kPa, preferably 3-5 kPa.

[0024] In the present application, the obtained polyether polyol has a purity of greater than 99.0%, a potassium ion content of less than 3 ppm, a hydroxyl value of 56-65 mgKOH / g, and a viscosity of 400-600 cp at room temperature.

[0025] In the present application, the obtained polyether polyol can be used to produce soft foam sponge. The addition amount is 5-100 wt% based on the total mass of the polyether polyol in the sponge formula, without affecting the performance of the sponge. The formula and preparation method of the soft foam can refer to the patent CN1180689A.

[0026] The present application has the following beneficial effects:

[0027] (1) A simple, effective and low-cost method for purifying soft foam alcoholysis product to obtain soft foam polyether polyol is developed.

[0028] (2) The obtained polyether polyol has high purity, low metal ion content, moderate viscosity and hydroxyl value, can be used to produce soft foam sponge again, has excellent performance, low cost, and is very suitable for industrial application.

[0029] (3) The recycling of polyurethane soft foam sponge is truly realized, carbon emissions are reduced, and income is increased. DETAILED DESCRIPTION

[0030] The present application is described in detail below with reference to specific examples of the present application, but these examples are not to be construed as limiting the present application in any manner.

[0031] Sources of raw materials and testing equipment:

[0032] General process for preparing polyurethane soft foam alcoholysis products: First, heat the required alcoholysis agent dipropylene glycol to 60°C, add 0.2wt% of potassium hydroxide as a catalyst, stir for 0.5 hours to fully dissolve, and then heat to 200°C. Add the required soft foam sponge cut into small pieces of 2*2*2cm to the above potassium alcohol solution, and after the addition is complete, react for 3-5 hours, cool, and collect the alcoholysis product.

[0033] Polar solvents and inorganic acids are reagent grade, and the supplier is Komiyu.

[0034] Drying equipment: A fume hood and a general air-blowing drying oven are used for drying.

[0035] Soft foam sponge foaming formula: soft foam polyether polyol: 100 parts; TDI-80: 24.4 parts; water: 3.85 parts; silicone oil: 0.8 parts; tin catalyst: 0.28 parts; amine catalyst: 0.25 parts.

[0036] Foaming operation process: First, weigh the required soft foam polyether polyol, water, silicone oil, tin catalyst, and amine catalyst in sequence, stir at 800rpm for 10 minutes to obtain white material. Second, weigh the required TDI-80, quickly pour it into the above white material, and then stir at 3000rpm for 8-10s. Pour the reaction liquid into a foaming box for foaming. The foam is cured in a constant temperature and humidity chamber at 45-55% humidity and 21-25°C for 72 hours. After cutting, test the performance.

[0037] Apparent hardness testing instrument: Shore A hardness tester, Gao Tie Testing Instrument Co., Ltd., GT-GS-MG.

[0038] Resilience performance testing instrument: Foam plastic ball drop resilience tester, Gao Tie Testing Instrument Co., Ltd., SL-SLH-500.

[0039] Indentation hardness testing instrument: Universal testing machine, Gao Tie Testing Instrument Co., Ltd., TCS-2000-D.

[0040] Sponge index requirements: foam discharge time 110-120s, density 29.5-30.5kg / m3, apparent hardness 40-45MPa, resilience performance 18.5-21.5%, 25% indentation hardness 60-65MPa.

[0041] Soft foam polyether polyol F3156 and TDI-80 are sourced from Wanhua Chemical.

[0042] Silicone oil, tin and amine catalyst, technical grade, supplier is Momentive.

[0043] Demulsifier: technical grade, supplier is PPG.

[0044] Example 1

[0045] First, 0.75 kg of glycolysis agent dipropylene glycol was heated to 60°C, 0.015 kg of potassium hydroxide was added as catalyst, and after stirring for 0.5 hours to fully dissolve, the temperature was raised to 200°C, 4.25 kg of soft foam sponge cut into 2*2*2 cm small pieces was gradually added to the above potassium alcoholate solution, after the addition was completed, the reaction was carried out for 3 hours, and after cooling, the alcoholysis product 5 kg was obtained, the indexes were as follows: soft foam polyol content 60.0%; TDA content 20.0%, glycolysis agent content 15.0%, macromolecular structure impurity content 5.0%.

[0046] Secondly, 6 kg of 10% hydrochloric acid aqueous solution and 6.05 kg of dichloromethane solvent were prepared.

[0047] S1, pH adjustment stage: using 10% hydrochloric acid aqueous solution to adjust the pH value of soft foam sponge alcoholysis product to 2, forming a mixed emulsion.

[0048] S2, demulsification and phase separation: 0.165 kg of demulsifier polyoxyethylene polyoxypropylene alkyl alcohol ether with 8 degrees of ethylene oxide polymerization, 12 degrees of propylene oxide polymerization and 15 degrees of alkyl carbon chain was added to the mixed emulsion formed in S1 at room temperature, stirred and then placed for 0.5 h to separate the phases, obtaining the organic phase.

[0049] S3, extraction of polyether polyol: using 6.05 kg of organic solvent to elute the organic phase obtained in S2, then rotary evaporation to remove the organic solvent at a temperature of 20°C and an absolute pressure of 3 kPa, obtaining the polyether polyol.

[0050] The indexes of the recovered polyether polyol were: purity 99.3%, potassium ion content 1.9 ppm, hydroxyl value 60.5 mgKOH / g, and viscosity 417 cp at room temperature.

[0051] The indexes of the foam sponge were: 100% using the recovered polyether polyol, blowing time 117 s, density 30.2 kg / m3, apparent hardness 45 MPa, and resilience performance 21%, 25% indentation hardness 60 MPa.

[0052] Example 2

[0053] First, 0.5 kg of alcoholysis agent dipropylene glycol is heated to 60°C, 0.01 kg of potassium hydroxide is added as a catalyst, and after stirring for 0.5 hours to fully dissolve, the temperature is raised to 200°C, 4.5 kg of soft sponge cut into 2*2*2 cm small pieces is gradually added to the above potassium alcoholate solution, after the addition is completed, the reaction is carried out for 3 hours, and after cooling, the alcoholysis product 5 kg is obtained. The indicators are as follows: soft polyol content 70.0%; TDA content 15.0%, alcoholysis agent content 10.0%, macromolecular structure impurity content 5.0%.

[0054] Secondly, 5 kg of 15% hydrochloric acid and nitric acid aqueous solution, 6.50 kg of dichloromethane and ethyl acetate mixed polar solvent.

[0055] S1, pH adjustment stage: using 15% hydrochloric acid and nitric acid aqueous solution to adjust the pH value of soft sponge alcoholysis product to 3.0, forming a mixed emulsion.

[0056] S2, demulsification and phase separation: 0.25 kg of demulsifier polyoxyethylene polyoxypropylene alkyl alcohol ether with epoxy ethylene polymerization degree 10, epoxy propylene polymerization degree 10, and alkyl carbon chain number 18 is added to the mixed emulsion formed in S1 at room temperature, stirred and then placed for 1.0 h to separate the phases, and obtain the organic phase.

[0057] S3, extraction of polyether polyol: using 6.50 kg of organic solvent to elute the organic phase obtained in S2, and then removing the organic solvent under the conditions of temperature 25°C and absolute pressure 5 kPa by rotary evaporation to obtain polyether polyol.

[0058] The indicators of the recovered polyether polyol are: purity 99.0%, potassium ion content 2.9 ppm, hydroxyl value 64.5 mgKOH / g, and viscosity 538 cp at room temperature.

[0059] The indicators of the sponge are: 5% of the recovered polyether polyol is used in the soft polyether polyol, blowing time 110 s, density 29.5 kg / m3, apparent hardness 40 MPa, and resilience performance 18.5%, 25% indentation hardness 60 MPa.

[0060] Example 3

[0061] First, 0.69 kg of alcoholysis agent dipropylene glycol is heated to 60°C, 0.0138 kg of potassium hydroxide is added as a catalyst, and after stirring for 0.5 hours to fully dissolve, the temperature is raised to 200°C, 4.31 kg of soft sponge cut into 2*2*2 cm small pieces is gradually added to the above potassium alcoholate solution, after the addition is completed, the reaction is carried out for 3 hours, and after cooling, the alcoholysis product 5 kg is obtained. The indicators are as follows: soft polyol content 63.5%; TDA content 19.5%, alcoholysis agent content 13.8%, macromolecular structure impurity content 3.2%.

[0062] Secondly, prepare 36.5% hydrochloric acid aqueous solution 3 kg, dichloromethane polar solvent 4.0 kg.

[0063] S1, pH adjustment stage: use 36.5% hydrochloric acid aqueous solution to adjust the pH value of the alcoholysis product of soft sponge to 1.0, forming a mixed emulsion.

[0064] S2, demulsification and phase separation: add 0.08 kg of demulsifier polyoxyethylene polyoxypropylene alkyl alcohol ether to the mixed emulsion formed in S1 at room temperature, the polyoxyethylene polymerization degree is 6, the polyoxypropylene polymerization degree is 10, and the alkyl carbon chain number is 12. After stirring, stand for 2.0 h, and then phase separate to obtain an organic phase.

[0065] S3, extraction of polyether polyol: use 4.0 kg of organic solvent to elute the organic phase obtained in S2, and then remove the organic solvent at a temperature of 15℃ and an absolute pressure of 2 kPa to obtain a polyether polyol.

[0066] The recovery polyether polyol index: purity 99.1%, potassium ion content 2.5 ppm, hydroxyl value 60.5 mgKOH / g, and viscosity 498 cp at room temperature.

[0067] The index of the sponge: 30% of the soft bubble polyether polyol uses the recovered polyether polyol, the blowing time is 115 s, the density is 30.1 kg / m3, the apparent hardness is 42.6 MPa, the rebound performance is 20.5%, and the 25% indentation hardness is 64.2 MPa.

[0068] Example 4

[0069] First, heat 0.63 kg of alcoholysis agent dipropylene glycol to 60℃, add 0.01 kg of potassium hydroxide as a catalyst, stir for 0.5 hours to fully dissolve, then heat to 200℃, and gradually add 4.37 kg of small pieces of soft sponge cut into 2*2*2 cm to the above potassium alcoholate solution, after the addition is completed, react for 3 hours, and then cool to obtain an alcoholysis product 5 kg. The index is as follows: soft polyol content 67.5%; TDA content 16.5%, alcoholysis agent content 12.6%, and macromolecular structure impurity content 3.4%.

[0070] Secondly, prepare 5% hydrochloric acid and sulfuric acid aqueous solution 8 kg, dichloromethane and ethyl acetate mixed polar solvent 9.1 kg.

[0071] S1, pH adjustment stage: use 5% hydrochloric acid and sulfuric acid aqueous solution to adjust the pH value of the alcoholysis product of soft sponge to 4.0, forming a mixed emulsion.

[0072] S2, demulsification and phase separation: 0.39 kg of demulsifier polyoxyethylene polyoxypropylene alkyl alcohol ether, with a polyethylene oxide degree of 10, a polypropylene oxide degree of 15, and an alkyl carbon chain number of 18, was added to the mixed emulsion formed in S1 at room temperature, and after stirring, the mixture was left to stand for 0.5 h before phase separation, to obtain an organic phase.

[0073] S3, extraction of polyether polyol: 9.1 kg of organic solvent was used to elute the organic phase obtained in S2, and then the organic solvent was removed by rotary evaporation under the conditions of a temperature of 35°C and an absolute pressure of 10 kPa, to obtain the polyether polyol.

[0074] The recovered polyether polyol had a purity of 99.2%, a potassium ion content of 1.7 ppm, a hydroxyl value of 59.3 mgKOH / g, and a viscosity of 567 cp at room temperature.

[0075] The foam sponge had a 50% content of the recovered polyether polyol, a blowing time of 117 s, a density of 30.1 kg / m3, an apparent hardness of 43.5 MPa, a rebound performance of 20.5%, and a 25% indentation hardness of 64.2 MPa.

[0076] Example 5

[0077] First, 0.605 kg of alcoholysis agent dipropylene glycol was heated to 60°C, 0.01 kg of potassium hydroxide was added as a catalyst, and after being fully dissolved by stirring for 0.5 h, the temperature was raised to 200°C. 4.91 kg of cut soft foam sponge with a size of 2*2*2 cm was gradually added to the above-mentioned potassium alcoholate solution, and after the addition was completed, the reaction was carried out for 3 h. After cooling, the alcoholysis product 5 kg was obtained. The indexes were as follows: soft polyol content 62.6%; TDA content 23.3%, alcoholysis agent content 12.1%, and macromolecular structure impurity content 2.0%.

[0078] Secondly, 6 kg of 12.5% hydrochloric acid aqueous solution and 6.6 kg of dichlorobenzene polar solvent were prepared.

[0079] S1, pH adjustment stage: 12.5% hydrochloric acid and sulfuric acid aqueous solution were used to adjust the pH of the soft foam sponge alcoholysis product to 2.5, to form a mixed emulsion.

[0080] S2, demulsification and phase separation: 0.22 kg of demulsifier polyoxyethylene polyoxypropylene alkyl alcohol ether, with a polyethylene oxide degree of 9, a polypropylene oxide degree of 11, and an alkyl carbon chain number of 14, was added to the mixed emulsion formed in S1 at room temperature, and after stirring, the mixture was left to stand for 0.75 h before phase separation, to obtain an organic phase.

[0081] S3, extraction of polyether polyol: 6.6 kg of organic solvent was used to elute the organic phase obtained in S2, and then the organic solvent was removed by rotary evaporation under the conditions of a temperature of 20°C and an absolute pressure of 4 kPa, to obtain the polyether polyol.

[0082] Recovery polyether polyol index: purity 99.1%, potassium ion content 1.1 ppm, hydroxyl value 57.2 mgKOH / g, viscosity 468 cp at room temperature.

[0083] Hair sponge index: 70% of the soft foam polyether polyol used is recycled, foam blowing time 113 s, density 30.1 kg / m3, apparent hardness 44.7 MPa, resilience 21.4%, 25% indentation hardness 64.9 MPa.

[0084] Comparative Example 1

[0085] First, 0.69 kg of alcoholysis agent dipropylene glycol was heated to 60°C, 0.0138 kg of potassium hydroxide was added as a catalyst, and after stirring for 0.5 hours to fully dissolve, the temperature was raised to 200°C. 4.31 kg of soft foam sponge cut into 2*2*2 cm pieces was gradually added to the above potassium alcohol solution, and after the addition was completed, the reaction was carried out for 3 hours, and after cooling, the alcoholysis product 5 kg was obtained. The index is as follows: soft foam polyol content 63.5%; TDA content 19.5%, alcoholysis agent content 13.8%, macromolecular structure impurity content 3.2%,

[0086] Hair sponge index: 100% of the above alcoholysis product is used, and the foam collapses, and a good-looking polyurethane soft foam sponge cannot be obtained.

[0087] Comparative Example 2

[0088] First, 0.69 kg of alcoholysis agent dipropylene glycol was heated to 60°C, 0.0138 kg of potassium hydroxide was added as a catalyst, and after stirring for 0.5 hours to fully dissolve, the temperature was raised to 200°C. 4.31 kg of soft foam sponge cut into 2*2*2 cm pieces was gradually added to the above potassium alcohol solution, and after the addition was completed, the reaction was carried out for 3 hours, and after cooling, the alcoholysis product 5 kg was obtained. The index is as follows: soft foam polyol content 63.5%; TDA content 19.5%, alcoholysis agent content 13.8%, macromolecular structure impurity content 3.2%,

[0089] Secondly, 3 kg of 36.5% hydrochloric acid aqueous solution and 4.0 kg of dichloromethane polar solvent were prepared.

[0090] S1, pH adjustment stage: use 36.5% hydrochloric acid aqueous solution to adjust the pH of the soft foam sponge alcoholysis product to 1.0 to form a mixed emulsion.

[0091] S2, polyether polyol extraction: use 4.0 kg of organic solvent to elute the organic phase obtained in S1, and then remove the organic solvent under the conditions of temperature 15°C and absolute pressure 2kPa to obtain the polyether polyol.

[0092] Reclaimed polyether polyol specifications: 97.1% purity, 5.9 ppm potassium ion content, 80.5 mg KOH / g hydroxyl value, 645 cp viscosity at room temperature.

[0093] Hair sponge specifications: 100% reclaimed polyether polyol used, collapsed, could not obtain a good shape polyurethane soft foam sponge.

[0094] Those skilled in the art can understand that some modifications or adjustments can be made to the present application under the teaching of the present specification. These modifications or adjustments should also be within the scope defined by the claims of the present application.

Claims

1. A method for extracting polyether polyols from polyurethane soft foam alcoholysis products, characterized in that, The method comprises the following steps: S1, pH adjustment stage: using aqueous solution of inorganic acid to adjust the pH value of polyurethane soft foam alcoholysis product to medium acidity, forming a mixed emulsion; S2, demulsification and phase separation: adding demulsifier to the mixed emulsion formed in S1 at room temperature, stirring and then standing for phase separation to obtain an organic phase; S3, extraction of polyether polyol: using polar solvent to elute the organic phase obtained in S2, removing the organic solvent to obtain polyether polyol; The demulsifier is polyoxyethylene polyoxypropylene alkyl alcohol ether, the polyoxyethylene polymerization degree is 6-10, the polyoxypropylene polymerization degree is 10-15, and the alkyl carbon chain number is 12-18.

2. The method of claim 1, wherein, The inorganic acid used is one or more of nitric acid, phosphoric acid, sulfuric acid and hydrochloric acid.

3. The method of claim 2, wherein, The concentration of the aqueous inorganic acid solution used is 5-36.5wt%.

4. The method of claim 3, wherein, The concentration of the aqueous inorganic acid solution used is 10-20wt%.

5. The method of claim 3, wherein, The concentration of the aqueous inorganic acid solution used is 10-15wt%.

6. The method according to any one of claims 1 to 5, characterized in that, The pH value of the alcoholysis product adjusted by the aqueous inorganic acid solution is between 1-6.

7. The method of claim 6, wherein, The pH value of the alcoholysis product adjusted by the aqueous inorganic acid solution is between 1-4.

8. The method of claim 6, wherein, The pH value of the alcoholysis product adjusted by the aqueous inorganic acid solution is between 2-3.

9. The method of claim 1, wherein, The polyoxyethylene polyoxypropylene alkyl alcohol ether has a polyoxyethylene polymerization degree of 8-10, a polyoxypropylene polymerization degree of 10-12, and an alkyl carbon chain number of 15-18.

10. The method according to claim 1 or 9, characterized in that, The addition amount of the polyoxyethylene polyoxypropylene alkyl alcohol ether is 1-3wt% of the mass of the mixed emulsion in S1.

11. The method of claim 10, wherein, The addition amount of the polyoxyethylene polyoxypropylene alkyl alcohol ether is 1.5-2.5wt% of the mass of the mixed emulsion in S1.

12. The method of claim 1, wherein, After adding the demulsifier to the mixed emulsion, the stirring and standing for phase separation are carried out for 0.5-2h.

13. The method of claim 12, wherein, After adding the demulsifier to the mixed emulsion, the stirring and standing for phase separation are carried out for 0.5-1.5h.

14. The method of claim 12, wherein, After adding the demulsifier to the mixed emulsion, the stirring and standing for phase separation are carried out for 0.5-1.0h.

15. The method of claim 1, wherein, The polar solvent used includes one or more of ethyl acetate, butyl acetate, dichloromethane, trichloromethane, acetone, benzene, chlorobenzene, and dichlorobenzene.

16. The method of claim 1 or 15, wherein, The use amount of the polar solvent is 50-70wt% of the mass of the mixed emulsion in S1.

17. The method of claim 1 or 15, wherein, The use amount of the polar solvent is 55-65wt% of the mass of the mixed emulsion in S1.

18. The method of claim 1 or 15, wherein, The removal method of the polar solvent includes room temperature evaporation, atmospheric distillation or rotary evaporation.

19. The method of claim 18, wherein, The rotary evaporation temperature is 15-35℃, and the absolute pressure is 2-10kPa.

20. The method of claim 18, wherein, The rotary evaporation temperature is 20-25℃, and the absolute pressure is 3-5kPa.

21. Use of a polyether polyol prepared according to the method of any one of claims 1 to 20, characterized in that The polyether polyol is used for producing soft foam sponge, and the addition amount of the polyether polyol obtained by the method of any one of claims 1-20 is adjusted to be between 5-100wt% based on the total mass of the polyether polyol in the sponge formula.