Bio-based flame-retardant polyether polyol and synthesis method thereof

Abstract

The invention discloses bio-based flame-retardant polyether polyol and a synthesis method thereof, and relates to the technical field of new chemical materials and biomass utilization. The bio-based flame-retardant polyether polyol is obtained by carrying out arbuzov reaction on halogenated starch liquefied polyol and phosphorous acid triester, and the halogenated starch liquefied polyol is prepared from bio-based starch, a liquefying agent, a halogenated dihydric alcohol liquefying auxiliary agent and a catalyst. The bio-based flame-retardant polyether polyol disclosed by the invention can be directly used for preparing flame-retardant polyurethane foam, the polyurethane foam can show excellent flame-retardant property under the condition of no additional flame retardant, and meanwhile, the optimization of a network structure in the flame-retardant polyurethane foam is also facilitated, so that the flame-retardant polyurethane foam has excellent flame-retardant property. The flame-retardant polyurethane foam with low apparent density and high compression strength can be obtained, and the light weight and the structural stability of the polyurethane foam are further improved.

Description

Technical Field

[0001] The present application relates to the technical field of new chemical materials and biomass utilization, and in particular to a bio-based flame-retardant polyether polyol and a synthesis method thereof. Background Art

[0002] Polyurethane (PU), as the world's fifth largest synthetic polymer material, plays an important role in daily life and industrial manufacturing due to its excellent mechanical properties, thermal insulation effect and chemical corrosion resistance. According to statistics, in 2020, China's polyurethane production reached 13 million tons, accounting for 45% of the world's total production, and consumption exceeded 12 million tons. It is expected that by 2026, China's polyurethane consumption will exceed 16 million tons.

[0003] However, in the synthesis of traditional polyurethane, polyols and polyisocyanates are mainly derived from petroleum resources, which does bring convenience to industrial production and daily life, but at the same time it also increases the consumption of petroleum resources and increases costs, which is inconsistent with the concept of sustainable development. In view of the limited regeneration capacity of petrochemical resources, turning to the use of renewable biomass resources to produce bio-based polyols to partially or completely replace petroleum-based polyols is a key path to promote the sustainable development of the polyurethane industry.

[0004] At present, in the field of polyurethane foam materials, the application exploration of biomass resources mainly focuses on starch, vegetable oil, lignin, wood and crop residues. The specific approaches are divided into two categories: (1) through a series of chemical reactions, biomass is converted into liquefied polyols rich in hydroxyl groups on the molecular chain, which serve as the key polyol component in the manufacture of polyurethane foam materials; (2) biomass is processed into a fine powder form and used as a modified additive for polyurethane foam materials.

[0005] Among them, patent CN112300376A discloses a method for preparing bio-based polyether polyols by solid acid catalyzing bamboo scraps liquefaction. A supported solid acid catalyst is synthesized with diatomite, mesoporous silica or silica gel as a carrier and used to catalyze bamboo scraps liquefaction, and bio-based polyether polyols can be obtained with a yield of 57.3%-72.4%. This method can effectively reduce the corrosion of acidic catalysts to equipment and reduce wastewater discharge, but the preparation process of the solid acid catalyst required by this method is relatively cumbersome and is not conducive to actual production.

[0006] Patent CN111499861A discloses a method for preparing biomass-based polyether polyols by non-catalytic solvent thermal liquefaction using agricultural waste as raw materials. Straw, bagasse, peanut shells, etc. are crushed and expanded, and then a liquefier with a mass of 2-4 times that of the raw materials is added. With the effect of the solvent thermal process, the raw materials can be effectively liquefied to obtain bio-based polyether polyols without using a catalyst. The obtained liquefied product can also be used for subsequent rigid polyurethane foaming.

[0007] However, polyurethane materials contain active carbamate groups and abundant carbon, hydrogen, and oxygen elements, and are usually highly flammable. When the bio-based polyether polyols prepared by the above method are used to prepare polyurethane materials, the flame retardant properties of polyurethane cannot be improved, which to a certain extent limits its application potential in multiple industries. Therefore, it is of great research significance to provide a bio-based polyether polyol with flame retardant properties. Summary of the invention

[0008] In order to improve the flame retardant properties of polyurethane materials made from bio-based polyether polyols, the present application provides a bio-based flame retardant polyether polyol and a synthesis method thereof.

[0009] In the first aspect, the present application provides a bio-based flame retardant polyether polyol using the following technical solution: A bio-based flame-retardant polyether polyol is obtained by arbuzov reaction of a halogenated starch liquefaction polyol and a triester of phosphite, wherein the halogenated starch liquefaction polyol is prepared from bio-based starch, a liquefaction agent, a halogenated diol liquefaction aid and a catalyst.

[0010] In the present application, a bio-based flame-retardant polyether polyol is obtained by arbuzov reaction of a halogenated starch liquefaction polyol and a triester of phosphite, wherein the halogenated starch liquefaction polyol, on the basis of common bio-based starch, a liquefactant and a catalyst, additionally introduces a halogenated diol liquefaction aid, and the halogenated diol liquefaction aid introduces halogens in the bio-based starch liquefaction process, thereby providing active sites for subsequent reactions with triester of phosphite, thereby obtaining a bio-based flame-retardant polyether polyol containing a phosphate group, and the bio-based flame-retardant polyether polyol can be directly used to prepare a flame-retardant polyurethane foam, and can make the polyurethane foam exhibit excellent flame retardant properties without the addition of an external flame retardant, and at the same time, is also beneficial to optimizing the network structure inside the flame-retardant polyurethane foam, and is beneficial to obtaining a flame-retardant polyurethane foam with low apparent density and high compressive strength, thereby further improving the lightness and structural stability of the polyurethane foam.

[0011] That is, the bio-based flame-retardant polyether polyol of the present application can make full use of bio-based starch, reduce dependence on petroleum resources, and is conducive to promoting the sustainable development of the polyurethane industry. At the same time, when used in the preparation of polyurethane foam, it can also improve the flame retardancy, lightness and structural stability of polyurethane foam.

[0012] In some specific embodiments, the amount of the triester phosphite is 15-25% by weight of the halogenated starch liquefaction polyol.

[0013] In the present application, the amount of triester phosphite is controlled to be 15-25% of the halogenated starch liquefaction polyol, which is beneficial to ensure the efficient progress of the arbuzov reaction and improve the yield of the bio-based flame retardant polyether polyol. At the same time, it is also beneficial to control the hydroxyl value of the bio-based flame retardant polyether polyol, which is beneficial to the subsequent foaming application of polyurethane foam.

[0014] In some specific embodiments, the weight ratio of the bio-based starch to the composite liquefier consisting of a liquefier and a halogenated diol liquefaction aid is 1:(2-7), the weight ratio of the liquefier to the halogenated diol liquefaction aid is (4-6):(6-4), and the amount of the catalyst used is 5-12% of the weight of the liquefier.

[0015] In the present application, by optimizing the ratio of each component in the halogenated starch liquefaction polyol within the above range, it is beneficial to ensure the efficient liquefaction reaction, improve the yield and purity of the halogenated starch liquefaction polyol, and reduce the generation of by-products.

[0016] Further preferably, the weight ratio of the bio-based starch to the composite liquefier consisting of a liquefier and a halogenated diol liquefaction aid is 1:(2.5-4), and the weight ratio of the liquefier to the halogenated diol liquefaction aid is 5:5, which is beneficial to improving the liquefaction rate of the bio-based starch.

[0017] Further preferably, the amount of the catalyst used is 8% by weight of the liquefier, which is beneficial to improving the liquefaction rate of the bio-based starch.

[0018] In some specific embodiments, the bio-based starch is at least one of corn starch, wheat starch, sweet potato starch, pea starch, and mung bean starch; the liquefier is at least one of epoxidized soybean oil, epoxidized castor oil, and epoxidized corn oil; the halogenated diol liquefaction aid is at least one of 3-chloropropylene glycol, 3-bromopropylene glycol, and 4-chloro-1,3-butanediol; and the catalyst is at least one of phosphoric acid, sulfuric acid, and p-toluenesulfonic acid.

[0019] More preferably, the liquefier is epoxidized soybean oil, the liquefaction aid is 3-chloropropanediol, and the catalyst is phosphoric acid.

[0020] In some specific embodiments, the preparation method of the halogenated starch liquefaction polyol is as follows: The bio-based starch, catalyst, liquefaction agent and halogenated diol liquefaction aid are mixed to carry out liquefaction reaction. After the liquefaction reaction is completed, an alkaline substance is added to neutralize it, and then the mixture is filtered, and the filtrate is refined and distilled to remove water to obtain a halogenated starch liquefied polyol.

[0021] In some specific embodiments, the liquefaction reaction is carried out at a temperature of 120-160° C. and for a time of 2-6 hours.

[0022] In the present application, the liquefaction reaction temperature of the bio-based starch is controlled to be 120-160° C. and the time is 2-6 hours, which is beneficial to improving the liquefaction rate of the bio-based starch and the yield of the halogenated starch liquefaction polyol.

[0023] In the second aspect, the present application provides a method for synthesizing a bio-based flame retardant polyether polyol using the following technical solution: A method for synthesizing a bio-based flame retardant polyether polyol comprises the following steps: The halogenated starch liquefaction polyol is mixed with a triester of phosphite to undergo an arbuzov reaction, followed by vacuum extraction to remove impurities, thereby obtaining a bio-based flame retardant polyether polyol.

[0024] In some specific embodiments, the temperature of the arbuzov reaction is 140-190° C., and the time is 4-8 hours.

[0025] In the present application, the temperature of the arbuzov reaction between the halogenated starch liquefaction polyol and the triester phosphite is controlled to be 140-190°C and the time is 4-8h, which not only helps the triester phosphite and the halogenated starch liquefaction polyol to fully react to generate the target product, but also avoids the occurrence of side reactions, which is beneficial to ensure the stability and flame retardant properties of the product.

[0026] Further preferably, the temperature of the arbuzov reaction is 150-170° C. and the time is 5-7 h.

[0027] In summary, this application at least includes the following beneficial technical effects: (1) The halogenated starch liquefaction polyol of the present application is based on the common bio-based starch, liquefaction agent and catalyst, and additionally introduces a halogenated diol liquefaction aid. The halogenated diol liquefaction aid introduces halogen in the bio-based starch liquefaction process, thereby providing active sites for the subsequent reaction with triester phosphite, thereby obtaining a bio-based flame retardant polyether polyol containing phosphate groups. The bio-based flame retardant polyether polyol can be directly used to prepare flame retardant polyurethane foam. In the absence of an external flame retardant, the polyurethane foam can exhibit excellent flame retardant properties. At the same time, it is also beneficial to optimize the network structure inside the flame retardant polyurethane foam, thereby obtaining a flame retardant polyurethane foam with low apparent density and high compressive strength, thereby further improving the lightness and structural stability of the polyurethane foam.

[0028] (2) In the present application, the liquefaction reaction temperature of the bio-based starch is controlled to be 120-160°C and the time is 2-6 hours, which is beneficial to improving the liquefaction rate of the bio-based starch and increasing the yield of the halogenated starch liquefaction polyol.

[0029] (3) In the present application, the temperature of the arbuzov reaction between the halogenated starch liquefaction polyol and the triester phosphite is controlled to be 140-190°C and the time is 4-8h, which not only helps the triester phosphite and the halogenated starch liquefaction polyol to fully react to generate the target product, but also avoids the occurrence of side reactions, which is beneficial to ensure the stability and flame retardant properties of the product. DETAILED DESCRIPTION

[0030] The present application is further described below in conjunction with specific experiments.

[0031] Among them, the molecular weight range of corn starch used in the following embodiments of this application is 50000-160000, the epoxidized soybean oil has an epoxide value of 6.7%, and a viscosity of 300-375mPa.s, but is not limited to the above corn starch and epoxidized soybean oil. Example

[0032] [Example 1] A bio-based flame retardant polyether polyol is obtained by arbuzov reaction of a halogenated starch liquefaction polyol and a triester of phosphite, wherein the halogenated starch liquefaction polyol is prepared from bio-based starch, a liquefaction agent, a halogenated diol liquefaction aid, and a catalyst. Specifically, in this embodiment, the bio-based starch is specifically corn starch, the liquefaction agent is specifically epoxy soybean oil, the halogenated diol liquefaction aid is specifically 3-chloropropylene glycol, the catalyst is specifically phosphoric acid, and the triester of phosphite is specifically triethyl phosphite.

[0033] In this embodiment, the weight ratio of the bio-based starch to the composite liquefier consisting of the liquefier and the halogenated diol liquefaction aid is 1:4, the weight ratio of the liquefier to the halogenated diol liquefaction aid is 5:5, the amount of the catalyst is 5% of the weight of the liquefier, and the amount of the triester phosphite is 20% of the weight of the halogenated starch liquefaction polyol.

[0034] In addition, in this embodiment, the preparation method of the bio-based flame retardant polyether polyol is as follows: S1. Add 50 g of bio-based starch, 100 g of epoxidized soybean oil, 100 g of 3-chloropropanediol and 5 g of phosphoric acid into a reactor, start stirring, mix evenly, react at 140° C. for 3 h, neutralize with sodium bicarbonate solution, then filter, separate the residue and the filtrate, and perform adsorption refining on the filtrate, and perform vacuum distillation to remove water to obtain a halogenated starch liquefied polyol; wherein the halogenated starch liquefied polyol of this embodiment has a hydroxyl value of 376.7 mgKOH / g and a viscosity of 468 mPa.s; S2. Pour 50 g of halogenated starch liquefaction polyol and 10 g of triethyl phosphite into a reactor and stir evenly, react at 150° C. for 5 h, and then remove impurities at a vacuum degree of -0.1 MPa to obtain a bio-based flame retardant polyether polyol; wherein the bio-based flame retardant polyether polyol of this embodiment has a hydroxyl value of 252.4 mgKOH / g and a viscosity of 662 mPa.s.

[0035] [Example 2] A bio-based flame-retardant polyether polyol is obtained by arbuzov reaction of a halogenated starch liquefaction polyol and a triester of phosphite, wherein the halogenated starch liquefaction polyol is prepared from bio-based starch, a liquefying agent, a halogenated diol liquefaction aid and a catalyst. Specifically, in this embodiment, the bio-based starch is corn starch, the liquefying agent is epoxidized soybean oil, the halogenated diol liquefaction aid is 3-chloropropylene glycol, the catalyst is phosphoric acid, and the triester of phosphite is triethyl phosphite.

[0036] In this embodiment, the weight ratio of the bio-based starch to the composite liquefier consisting of the liquefier and the halogenated diol liquefaction aid is 1:3, the weight ratio of the liquefier to the halogenated diol liquefaction aid is 5:5, the amount of the catalyst is 10.67% of the weight of the liquefier, and the amount of the triester phosphite is 15% of the weight of the halogenated starch liquefaction polyol.

[0037] In addition, in this embodiment, the preparation method of the bio-based flame retardant polyether polyol is as follows: S1. Add 50 g of bio-based starch, 75 g of epoxidized soybean oil, 75 g of 3-chloropropanediol and 8 g of phosphoric acid into a reactor, start stirring, mix evenly, react at 140° C. for 3 h, neutralize with sodium bicarbonate solution, and then filter to separate the residue and the filtrate, and perform adsorption refining on the filtrate and dewatering by vacuum distillation to obtain a halogenated starch liquefied polyol; wherein the halogenated starch liquefied polyol of this embodiment has a hydroxyl value of 354.3 mgKOH / g and a viscosity of 558 mPa.s; S2. Pour 50 g of halogenated starch liquefied polyol and 7.5 g of triethyl phosphite into a reactor and stir evenly, react at 150° C. for 4 h, and then remove impurities at a vacuum degree of -0.1 MPa to obtain a bio-based flame retardant polyether polyol; wherein the bio-based flame retardant polyether polyol of this embodiment has a hydroxyl value of 232.1 mgKOH / g and a viscosity of 604 mPa.s.

[0038] [Example 3] A bio-based flame-retardant polyether polyol is obtained by arbuzov reaction of a halogenated starch liquefaction polyol and a triester of phosphite, wherein the halogenated starch liquefaction polyol is prepared from bio-based starch, a liquefying agent, a halogenated diol liquefaction aid and a catalyst. Specifically, in this embodiment, the bio-based starch is corn starch, the liquefying agent is epoxidized soybean oil, the halogenated diol liquefaction aid is 3-chloropropylene glycol, the catalyst is phosphoric acid, and the triester of phosphite is triethyl phosphite.

[0039] In this embodiment, the weight ratio of the bio-based starch to the composite liquefier consisting of the liquefier and the halogenated diol liquefaction aid is 1:5, the weight ratio of the liquefier to the halogenated diol liquefaction aid is 5:5, the amount of the catalyst is 8% of the weight of the liquefier, and the amount of the triester phosphite is 25% of the weight of the halogenated starch liquefaction polyol.

[0040] In addition, in this embodiment, the preparation method of the bio-based flame retardant polyether polyol is as follows: S1. Add 50 g of bio-based starch, 125 g of epoxidized soybean oil, 125 g of 3-chloropropanediol and 10 g of phosphoric acid into a reactor, start stirring, mix evenly, react at 150° C. for 3 h, neutralize with sodium bicarbonate solution, and then filter to separate the residue and the filtrate, and perform adsorption refining on the filtrate and dewatering by vacuum distillation to obtain a halogenated starch liquefied polyol; wherein the halogenated starch liquefied polyol of this embodiment has a hydroxyl value of 361.4 mgKOH / g and a viscosity of 572 mPa.s; S2. Pour 50 g of halogenated starch liquefaction polyol and 12.5 g of triethyl phosphite into a reactor and stir evenly, react at 150° C. for 5 h, and then remove impurities at a vacuum degree of -0.1 MPa to obtain a bio-based flame retardant polyether polyol; wherein the bio-based flame retardant polyether polyol of this embodiment has a hydroxyl value of 247.6 mgKOH / g and a viscosity of 632 mPa.s.

[0041] [Example 4] A bio-based flame-retardant polyether polyol is obtained by arbuzov reaction of a halogenated starch liquefaction polyol and a triester of phosphite, wherein the halogenated starch liquefaction polyol is prepared from bio-based starch, a liquefactant, a halogenated diol liquefaction aid and a catalyst. Specifically, in this embodiment, the bio-based starch is corn starch, the liquefactant is epoxidized soybean oil, the halogenated diol liquefaction aid is 4-chloro-1,3-butanediol, the catalyst is sulfuric acid, and the triester of phosphite is trimethyl phosphite.

[0042] In this embodiment, the weight ratio of the bio-based starch to the composite liquefier consisting of the liquefier and the halogenated diol liquefaction aid is 1:4, the weight ratio of the liquefier to the halogenated diol liquefaction aid is 5:5, the amount of the catalyst is 8% of the weight of the liquefier, and the amount of the triester phosphite is 20% of the weight of the halogenated starch liquefaction polyol.

[0043] In addition, in this embodiment, the preparation method of the bio-based flame retardant polyether polyol is as follows: S1. Add 50 g of bio-based starch, 100 g of epoxidized soybean oil, 100 g of 4-chloro-1,3-butanediol and 8 g of sulfuric acid into a reactor, start stirring, mix evenly, react at 150° C. for 3 h, neutralize with sodium bicarbonate solution, and then filter to separate the residue and filtrate, and perform adsorption refining on the filtrate to remove water by vacuum distillation to obtain a halogenated starch liquefied polyol; wherein the halogenated starch liquefied polyol of this embodiment has a hydroxyl value of 332.8 mgKOH / g and a viscosity of 529 mPa.s; S2. Pour 50 g of halogenated starch liquefaction polyol and 10 g of trimethyl phosphite into a reactor and stir evenly, react at 150° C. for 6 h, and then remove impurities at a vacuum degree of -0.1 MPa to obtain a bio-based flame retardant polyether polyol; wherein the bio-based flame retardant polyether polyol of this embodiment has a hydroxyl value of 229.6 mgKOH / g and a viscosity of 654 mPa.s.

[0044] [Example 5] A bio-based flame retardant polyether polyol, which differs from [Example 1] in that: In this embodiment, the weight ratio of the bio-based starch to the composite liquefier consisting of the liquefier and the halogenated diol liquefaction aid is 1:7, the weight ratio of the liquefier to the halogenated diol liquefaction aid is 5:5, the amount of the catalyst is 5% of the weight of the liquefier, and the amount of the triester phosphite is 20% of the weight of the halogenated starch liquefaction polyol.

[0045] In addition, in this embodiment, the preparation method of the bio-based flame retardant polyether polyol is as follows: S1. Add 50 g of bio-based starch, 175 g of epoxidized soybean oil, 175 g of 3-chloropropanediol, and 8.75 g of phosphoric acid into a reactor, start stirring, mix evenly, react at 140° C. for 3 h, neutralize with sodium bicarbonate solution, and then filter to separate the residue and the filtrate, and perform adsorption refining on the filtrate and dewatering by vacuum distillation to obtain a halogenated starch liquefied polyol; wherein the halogenated starch liquefied polyol of this embodiment has a hydroxyl value of 403.5 mgKOH / g and a viscosity of 543 mPa.s; S2. Pour 50 g of halogenated starch liquefaction polyol and 10 g of triethyl phosphite into a reactor and stir evenly, react at 150° C. for 5 h, and then remove impurities at a vacuum degree of -0.1 MPa to obtain a bio-based flame retardant polyether polyol; wherein the bio-based flame retardant polyether polyol of this embodiment has a hydroxyl value of 324.1 mgKOH / g and a viscosity of 597 mPa.s.

[0046] [Example 6] A bio-based flame retardant polyether polyol, which differs from [Example 1] in that: In this embodiment, the weight ratio of the bio-based starch to the composite liquefier consisting of the liquefier and the halogenated diol liquefaction aid is 1:4, the weight ratio of the liquefier to the halogenated diol liquefaction aid is 2:8, the amount of the catalyst is 5% by weight of the liquefier, and the amount of the triester phosphite is 20% by weight of the halogenated starch liquefaction polyol.

[0047] In addition, in this embodiment, the preparation method of the bio-based flame retardant polyether polyol is as follows: S1. Add 50 g of bio-based starch, 40 g of epoxidized soybean oil, 160 g of 3-chloropropanediol and 2 g of phosphoric acid into a reactor, start stirring, mix evenly, react at 140° C. for 3 h, neutralize with sodium bicarbonate solution, and then filter to separate the residue and the filtrate, and perform adsorption refining on the filtrate and dewatering by vacuum distillation to obtain a halogenated starch liquefied polyol; wherein the halogenated starch liquefied polyol of this embodiment has a hydroxyl value of 336.8 mgKOH / g and a viscosity of 531 mPa.s; S2. Pour 50 g of halogenated starch liquefaction polyol and 10 g of triethyl phosphite into a reactor and stir evenly, react at 150° C. for 5 h, and then remove impurities at a vacuum degree of -0.1 MPa to obtain a bio-based flame retardant polyether polyol; wherein the bio-based flame retardant polyether polyol of this embodiment has a hydroxyl value of 286.2 mgKOH / g and a viscosity of 622 mPa.s.

[0048] [Example 7] A bio-based flame retardant polyether polyol, which differs from [Example 1] in that: In this embodiment, the weight ratio of the bio-based starch to the composite liquefier consisting of the liquefier and the halogenated diol liquefaction aid is 1:4, the weight ratio of the liquefier to the halogenated diol liquefaction aid is 8:2, the amount of the catalyst is 5% by weight of the liquefier, and the amount of the triester phosphite is 20% by weight of the halogenated starch liquefaction polyol.

[0049] In addition, in this embodiment, the preparation method of the bio-based flame retardant polyether polyol is as follows: S1. Add 50 g of bio-based starch, 160 g of epoxidized soybean oil, 40 g of 3-chloropropanediol and 8 g of phosphoric acid into a reactor, start stirring, mix evenly, react at 140° C. for 3 h, neutralize with sodium bicarbonate solution, and then filter to separate the residue and the filtrate, and perform adsorption refining on the filtrate and dewatering by vacuum distillation to obtain a halogenated starch liquefied polyol; wherein the halogenated starch liquefied polyol of this embodiment has a hydroxyl value of 349.7 mgKOH / g and a viscosity of 549 mPa.s; S2. Pour 50 g of halogenated starch liquefaction polyol and 10 g of triethyl phosphite into a reactor and stir evenly, react at 150° C. for 5 h, and then remove impurities at a vacuum degree of -0.1 MPa to obtain a bio-based flame retardant polyether polyol; wherein the bio-based flame retardant polyether polyol of this embodiment has a hydroxyl value of 209.8 mgKOH / g and a viscosity of 643 mPa.s.

[0050] Performance testing 1. Liquefaction rate: The liquefaction rate of corn starch in step S1 of each embodiment 1-7 and the yield of bio-based flame retardant polyether polyol in step S2 of each embodiment 1-7 were tested and recorded in the following Table 1. Wherein, liquefaction rate (%) = 1-(weight of residue after drying / mass of starch × 100%).

[0051] Preparation of polyurethane foam: The halogenated starch liquefied polyol obtained in step S1 of each embodiment 1-7 and the bio-based flame retardant polyether polyol obtained in step S2 are respectively used to prepare polyurethane foam, wherein polyurethane foam 1 is prepared from halogenated starch liquefied polyol, silicone oil L-580, dibutyltin dilaurate, and MDI in a weight ratio of 20:0.3:0.016:30, and polyurethane foam 2 is prepared from bio-based flame retardant polyether polyol, silicone oil L-580, dibutyltin dilaurate, and MDI in a weight ratio of 20:0.3:0.016:30.

[0052] 2. Apparent density: Take the above polyurethane foam and test the apparent density with reference to GB / T 6343-2009.

[0053] 3. Compression strength: Take the above polyurethane foam and test the compression strength according to GB / T 8813-2008.

[0054] 4. Thermal conductivity: Take the above polyurethane foam and test the thermal conductivity with reference to GB / T 3399-1982.

[0055] 5. Limiting oxygen index: Take the above polyurethane foam and test the limiting oxygen index according to GB / T 2406.2-2009.

[0056] Table 1 Sample Liquefaction rate / % Yield / % Example 1 90.2 90.5 Example 2 80.3 78.5 Example 3 87.6 82.1 Example 4 87.6 83.6 Example 5 88.6 85.2 Example 6 83.3 73.1 Example 7 87.1 87.4 Table 2 Table 3 According to the test results in Example 1 and Example 5 and Table 1, the weight ratio of bio-based starch to the composite liquefier consisting of a liquefier and a halogenated diol liquefaction aid is in the range of 1:(2.5-4), which is more conducive to improving the liquefaction rate of bio-based starch.

[0057] According to the test results in Example 1, Example 7-8 and Table 1, the weight ratio of the liquefier to the halogenated diol liquefaction aid is in the range of (4-6): (6-4), which is more conducive to improving the liquefaction rate of the bio-based starch.

[0058] According to the test data corresponding to each embodiment in Table 2 and Table 3, it can be known that compared with directly using halogenated starch liquefied polyol and MDI to prepare polyurethane foam, the use of bio-based polyether polyol obtained by reacting halogenated starch liquefied polyol with triester phosphite in the present application to prepare polyurethane foam is conducive to obtaining polyurethane foam with lower apparent density and higher compression strength. At the same time, the limiting oxygen index of the polyurethane foam is also significantly increased, that is, when the bio-based polyether polyol of the present application is used to prepare polyurethane foam, the flame retardant performance of the polyurethane foam is better.

[0059] This specific implementation manner is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make non-creative modifications to the specific implementation manner as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. A bio-based flame retardant polyether polyol, characterized in that: The halogenated starch liquefaction polyol is obtained by an arbuzov reaction with a phosphite triester, wherein the halogenated starch liquefaction polyol is prepared from bio-based starch, a liquefaction agent, a halogenated diol liquefaction aid and a catalyst.

2. The bio-based flame retardant polyether polyol according to claim 1, characterized in that: The amount of the triester phosphite used is 15-25% by weight of the halogenated starch liquefaction polyol.

3. The bio-based flame retardant polyether polyol according to claim 1, characterized in that: The weight ratio of the bio-based starch to the composite liquefier consisting of a liquefier and a halogenated diol liquefaction aid is 1:(2-7), the weight ratio of the liquefier to the halogenated diol liquefaction aid is (4-6):(6-4), and the amount of the catalyst used is 5-12% of the weight of the liquefier.

4. The bio-based flame retardant polyether polyol according to claim 3, characterized in that: The weight ratio of the bio-based starch to the composite liquefier consisting of a liquefier and a halogenated diol liquefaction aid is 1:(2.5-4).

5. The bio-based flame retardant polyether polyol according to claim 1, characterized in that: The liquefier is at least one of epoxidized soybean oil, epoxidized castor oil, and epoxidized corn oil; the halogenated diol liquefaction aid is at least one of 3-chloropropylene glycol, 3-bromopropylene glycol, and 4-chloro-1,3-butanediol; and the catalyst is at least one of phosphoric acid, sulfuric acid, and p-toluenesulfonic acid.

6. A bio-based flame retardant polyether polyol according to any one of claims 1 to 5, characterized in that: The preparation method of the halogenated starch liquefaction polyol is as follows: Bio-based starch, catalyst, liquefaction agent, halogenated diol liquefaction aid are mixed for liquefaction reaction. After the liquefaction reaction is completed, an alkaline substance is added to neutralize it, and then the mixture is filtered, and the filtrate is refined and distilled to remove water to obtain a halogenated starch liquefied polyol.

7. The bio-based flame retardant polyether polyol according to claim 6, characterized in that: The temperature of the liquefaction reaction is 120-160° C. and the time is 2-6 hours.

8. A method for synthesizing a bio-based flame retardant polyether polyol as claimed in any one of claims 1 to 7, characterized in that: The following steps are involved: The halogenated starch liquefaction polyol is mixed with a triester of phosphite to undergo an arbuzov reaction, followed by vacuum extraction to remove impurities, thereby obtaining a bio-based flame retardant polyether polyol.

9. The method for synthesizing the bio-based flame retardant polyether polyol according to claim 8, characterized in that: The temperature of the arbuzov reaction is 140-190° C. and the time is 4-8 hours.

10. The method for synthesizing the bio-based flame retardant polyether polyol according to claim 9, characterized in that: The temperature of the arbuzov reaction is 150-170° C. and the time is 5-7 hours.

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