Polyurethane foam based on halogen-free bio-based flame-retardant polyether polyol and its preparation method

Abstract

This invention discloses a polyurethane foam based on halogen-free bio-based flame-retardant polyether polyol and its preparation method, relating to the field of flame-retardant material preparation technology. This application synthesizes a phosphorus- and silicon-containing bio-based flame-retardant polyether polyol through three steps: transesterification, dehydrogenation condensation, and hydrosilylation. This polyol is then reacted with isocyanate monomers, blowing agents, and other additives to obtain a polyurethane foam. The polyurethane foam is then sequentially impregnated in a dispersion containing modified aluminum hydroxide and a polyphosphoric acid solution. Through the reaction of amino groups with polyphosphoric acid, an organic-inorganic hybrid flame-retardant protective layer is formed on the surface of the polyurethane foam, resulting in polyurethane foam, further enhancing its flame retardancy.

Description

Technical Field

[0001] This invention relates to the field of flame retardant material preparation technology, specifically to polyurethane foam based on halogen-free bio-based flame retardant polyether polyols and its preparation method. Background Technology

[0002] Polyurethane foam is mainly divided into two types: flexible and rigid. Flexible polyurethane has an open-cell structure, while rigid polyurethane has a closed-cell structure. Flexible polyurethane has a wide range of applications, and its main function is cushioning. It is commonly used in sofas, pillows, toys, cushions, sound insulation materials, etc.

[0003] However, flexible polyurethane is prone to fire due to its high hydrocarbon segment content and large specific surface area. It is a flammable material, and its combustion spreads rapidly, producing toxic gases, posing a huge threat to people's lives and property.

[0004] Therefore, this application aims to provide polyurethane foam based on halogen-free bio-based flame-retardant polyether polyol and its preparation method. By preparing a flame-retardant polyether polyol, making it into polyurethane foam, and then impregnating it on the surface of the polyurethane to form an organic-inorganic hybrid flame-retardant protective layer, the flame retardancy of the polyurethane foam is further improved. Summary of the Invention

[0005] The purpose of this invention is to provide polyurethane foam based on halogen-free bio-based flame-retardant polyether polyols and its preparation method, so as to solve the problems raised in the prior art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a method for preparing polyurethane foam based on halogen-free bio-based flame-retardant polyether polyols, comprising the following steps:

[0007] Step 1: Mix bio-based flame retardant polyether polyol, catalyst, foaming agent and stabilizer, stir evenly, let stand, then add isocyanate monomer, stir to foam and mature to obtain polyurethane foam.

[0008] Step 2: Mix modified aluminum hydroxide with an aqueous ethanol solution, ultrasonically disperse to obtain a dispersion, immerse the polyurethane foam in the dispersion and press it 10-20 times, take it out and dry it, then immerse it in a polyphosphoric acid solution, microwave it, take it out and dry it to obtain polyurethane foam.

[0009] Furthermore, in step 1, the mass ratio of bio-based flame-retardant polyether polyol, catalyst, foaming agent, and stabilizer is 100:(0.15~0.25):(1.0~2.0):(1.0~2.0).

[0010] Furthermore, in step 1, the catalyst is one or a mixture of two of the following: triethylenediamine and bis(dimethylaminoethyl) ether.

[0011] In step 1, the foaming agent is water;

[0012] In step 1, the stabilizer is one or a mixture of silicone oil L-580, silicone oil B-8681, and silicone oil B-8110;

[0013] In step 1, the isocyanate monomer is one or a mixture of hexamethylene diisocyanate, toluene diisocyanate, and 4,4-diphenylmethane diisocyanate.

[0014] Furthermore, in step 1, the process conditions for stirring and foaming are: temperature 40~45℃, time 4~5min;

[0015] In step 1, the curing process conditions are: 25~30℃, time 40~48h.

[0016] Furthermore, in step 2, the mass ratio of modified aluminum hydroxide to ethanol aqueous solution is 1:(50~80).

[0017] In step 2, the mass ratio of polyurethane foam, dispersion, and polyphosphoric acid solution is 1:(50~100):(60~80).

[0018] The mass fraction of the ethanol aqueous solution is 20-60%;

[0019] The mass fraction of the polyphosphoric acid solution is 1.5~2.5%.

[0020] Furthermore, in step 2, the ultrasonic dispersion process conditions are: frequency 20~40kHz, time 5~15min.

[0021] Furthermore, in step 2, the microwave reaction process conditions are: power 800~1000W, time 1~3min;

[0022] In step 2, the drying process conditions are: temperature 40~60℃, time 6~8h.

[0023] Furthermore, in step 1, the preparation process of the bio-based flame-retardant polyether polyol is as follows:

[0024] S1: Mix dimethyl methyl phosphate and diethylene glycol, and heat to react to obtain a hydroxyl-terminated flame retardant;

[0025] S2: Mix hydrogen-containing silicone oil, hydroxyl-terminated flame retardant and tributyltin oxide, and heat to react under nitrogen atmosphere to obtain flame-retardant hydrogen-containing organosilicon.

[0026] S3: Mix double-bond bio-based polyether polyol, flame-retardant hydrogen-containing organosilicon, and chloroplatinic acid solution, and heat to react to obtain bio-based flame-retardant polyether polyol.

[0027] Furthermore, in S1, the molar ratio of dimethyl methyl phosphate to diethylene glycol is 1:(1.8~2.2).

[0028] Furthermore, in S1, the process conditions for the heating reaction are: temperature 130~150℃, time 0.6~1.0h.

[0029] Furthermore, in S2, the mass ratio of hydrogen-containing silicone oil, hydroxyl-terminated flame retardant, and tributyltin oxide is (20~40):10:(0.3~0.5).

[0030] Furthermore, in S2, the process conditions for the heating reaction are: temperature 60~80℃, time 25~45min.

[0031] Furthermore, in S3, the mass ratio of double-bonded bio-based polyether polyol, flame-retardant hydrogen-containing organosilicon, and chloroplatinic acid solution is 10:(11~13):(0.02~0.04).

[0032] Furthermore, in S3, the chloroplatinic acid solution is prepared by mixing chloroplatinic acid and isopropanol in a mass ratio of (1~5):(95~99).

[0033] Furthermore, in S3, the process conditions for the heating reaction are: temperature 100~110℃, time 1.8~2.2h.

[0034] Furthermore, in S3, the preparation process of the double-bond bio-based polyether polyol is as follows:

[0035] A polyhydroxy compound and potassium hydroxide were mixed and dehydrated under a nitrogen atmosphere by evacuating to a vacuum of -0.1 MPa. Then, epoxidized soybean oil and allyl glycidyl ether were added and the mixture was heated to obtain a double-bonded bio-based polyether polyol.

[0036] Furthermore, the mass ratio of the polyhydroxy compound, potassium hydroxide, epoxidized soybean oil, and allyl glycidyl ether is 100:(1.0~1.4):(100~110):(200~220).

[0037] Furthermore, the polyhydroxy compound is one or a mixture of glycerol, mannitol, and sorbitol.

[0038] Furthermore, the dehydration process conditions are: temperature 110~120℃, time 0.5~1.0h;

[0039] The process conditions for the heating reaction are: temperature 110~120℃, time 1.0~1.5h.

[0040] In the above technical solution, a compound containing phosphorus with hydroxyl groups at both ends is generated through transesterification reaction between dimethyl methyl phosphate and diethylene glycol, namely a hydroxyl-terminated flame retardant. Then, the hydroxyl groups undergo dehydrogenation condensation with the silane-hydrogen bonds of hydrogen-containing silicone oil under the action of tributyltin oxide to obtain a flame-retardant hydrogen-containing organosilicon. Finally, the double bonds of the double-bonded bio-based polyether polyol undergo an addition reaction with the flame-retardant hydrogen-containing organosilicon to obtain a bio-based flame-retardant polyether polyol. The molecular chain of the bio-based flame-retardant polyether polyol contains phosphorus and silicon, and the flame retardancy of the polyether polyol is enhanced through the synergistic effect of the two.

[0041] Furthermore, in step 2, the modified aluminum hydroxide is prepared by the following process:

[0042] Step A: Mix the amino coupling agent, ethanol, and deionized water to obtain a mixture. Mix aluminum hydroxide with the mixture, stir to react, wash, and dry to obtain aminated aluminum hydroxide.

[0043] Step B: Mix cyanuric chloride and acetonitrile, stir well, add aminated aluminum hydroxide, microwave reaction, wash and dry to obtain modified aluminum hydroxide.

[0044] Furthermore, in step A, the mass ratio of amino coupling agent, ethanol, and deionized water is 1:(10~15):(15~20).

[0045] In step A, the mass ratio of aluminum hydroxide to the mixed solution is 1:(50~60).

[0046] Furthermore, in step A, the process conditions for the stirring reaction are: temperature 25~35℃, time 1.5~2.5h.

[0047] Furthermore, in step A, the amino coupling agent is one or a mixture of two of KH-550 and KH-554.

[0048] Furthermore, in step B, the ratio of cyanuric chloride, acetonitrile, and aminated aluminum hydroxide is (15~25) g: 500 mL: (60~90) g.

[0049] Furthermore, in step B, the microwave reaction process conditions are: power 800~1000W, time 1~2min.

[0050] Furthermore, the drying process conditions are: temperature 45~50℃, time 10~12h.

[0051] In the above technical solution, aluminum hydroxide is modified by an amino coupling agent to obtain aminated aluminum hydroxide. Then, modified aluminum hydroxide is obtained by nucleophilic substitution of the amino group with cyanuric chloride. The excess of aminated aluminum hydroxide is controlled so that the remaining amino group can react with polyphosphoric acid to form an organic-inorganic hybrid flame-retardant protective layer on the surface of polyurethane foam, further improving the flame retardancy of polyurethane foam.

[0052] Compared with the prior art, the beneficial effects of the present invention are:

[0053] 1. This application first synthesizes a double-bonded bio-based polyether polyol by ring-opening reaction of a polyhydroxy compound with epoxidized soybean oil and allyl glycidyl ether. Then, through a three-step reaction of transesterification, dehydrogenation condensation, and hydrosilylation, a bio-based flame-retardant polyether polyol containing phosphorus and silicon is synthesized. The flame retardancy of the bio-based polyether polyol is enhanced through the synergistic effect of phosphorus and silicon. The bio-based flame-retardant polyether polyol prepared in this application has high functionality and large molecular weight, which can make the polyurethane foam prepared by it have better resilience compared with commercially available polyether polyols.

[0054] 2. This application improves the flame retardancy of polyurethane foam by sequentially impregnating the prepared polyurethane foam with a dispersion containing modified aluminum hydroxide and a polyphosphoric acid solution. Through the reaction between polyphosphoric acid and amino groups, an organic-inorganic hybrid flame retardant protective layer is formed on the surface of the polyurethane foam. Detailed Implementation

[0055] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0056] In the following specific implementation;

[0057] The catalyst is triethylenediamine;

[0058] The foaming agent is water;

[0059] The stabilizer is silicone oil L-580;

[0060] The isocyanate monomer is hexamethylene diisocyanate;

[0061] Hydrogen-containing silicone oil, model 202, sourced from Wuhan Kemic Biomedical Technology Co., Ltd.

[0062] The polyhydroxy compound is mannitol;

[0063] The amino coupling agent is KH-550;

[0064] Polyether polyol, model 220, originates from Haian Petrochemical Plant in Jiangsu Province.

[0065] Example 1: A method for preparing polyurethane foam based on halogen-free bio-based flame-retardant polyether polyols, comprising the following steps:

[0066] (1) Preparation of modified aluminum hydroxide:

[0067] Step A: Mix the amino coupling agent, ethanol, and deionized water to obtain a mixed solution. Mix aluminum hydroxide with the mixed solution, stir to react, wash, and dry to obtain aminated aluminum hydroxide. Step B: Mix cyanuric chloride and acetonitrile, stir evenly, add aminated aluminum hydroxide, microwave to react, wash, and dry to obtain modified aluminum hydroxide. In Step A, the mass ratio of amino coupling agent, ethanol, and deionized water is 1:15:20; the mass ratio of aluminum hydroxide to the mixed solution is 1:60; the stirring reaction conditions in Step A are: temperature 35℃, time 2.5h; in Step B, the ratio of cyanuric chloride, acetonitrile, and aminated aluminum hydroxide is 25g:500mL:90g; the microwave reaction conditions in Step B are: power 1000W, time 2min; the drying conditions are: temperature 50℃, time 12h.

[0068] (2) Preparation of double-bond bio-based polyether polyols:

[0069] A polyhydroxy compound and potassium hydroxide were mixed and dehydrated under a nitrogen atmosphere by evacuating to a vacuum of -0.1 MPa. Then, epoxidized soybean oil and allyl glycidyl ether were added, and the mixture was heated to obtain a double-bonded bio-based polyether polyol. The mass ratio of the polyhydroxy compound, potassium hydroxide, epoxidized soybean oil, and allyl glycidyl ether was 100:1.4:110:220. The dehydration process conditions were: temperature 120℃, time 1.0 h; the heating reaction process conditions were: temperature 120℃, time 1.5 h.

[0070] (3) Preparation of bio-based flame-retardant polyether polyols:

[0071] S1: Dimethyl methyl phosphate and diethylene glycol are mixed and heated to react, yielding a hydroxyl-terminated flame retardant; S2: Hydrogen-containing silicone oil, the hydroxyl-terminated flame retardant, and tributyltin oxide are mixed and heated under a nitrogen atmosphere to react, yielding a flame-retardant hydrogen-containing organosilicon; S3: Double-bond bio-based polyether polyol, flame-retardant hydrogen-containing organosilicon, and chloroplatinic acid solution are mixed and heated to react, yielding a bio-based flame-retardant polyether polyol; In S1, the molar ratio of dimethyl methyl phosphate to diethylene glycol is 1:2.2; In S1, the process conditions for the heating reaction are: temperature 150°C. The reaction conditions in S2 were: temperature 80℃, time 1.0 h; in S2, the mass ratio of hydrogen-containing silicone oil, hydroxyl-terminated flame retardant, and tributyltin oxide was 40:10:0.5; in S2, the heating reaction conditions were: temperature 80℃, time 45 min; in S3, the mass ratio of double-bonded bio-based polyether polyol, flame-retardant hydrogen-containing organosilicon, and chloroplatinic acid solution was 10:13:0.04; in S3, the chloroplatinic acid solution was prepared by mixing chloroplatinic acid and isopropanol at a mass ratio of 5:95; in S3, the heating reaction conditions were: temperature 110℃, time 2.2 h.

[0072] (4) Preparation of polyurethane foam:

[0073] Step 1: Mix bio-based flame-retardant polyether polyol, catalyst, foaming agent, and stabilizer, stir evenly, let stand, then add isocyanate monomer, stir to foam and mature to obtain polyurethane foam; Step 2: Mix modified aluminum hydroxide with ethanol aqueous solution, ultrasonically disperse to obtain dispersion, immerse polyurethane foam in dispersion, press 20 times, remove and dry, then immerse in polyphosphoric acid solution, microwave reaction, remove and dry to obtain polyurethane foam; In Step 1, the mass ratio of bio-based flame-retardant polyether polyol, catalyst, foaming agent, and stabilizer is 100:0.25:2.0:2.0; The stirring and foaming process conditions in Step 1 are: The temperature was 45℃ and the time was 5 min. In step 1, the curing conditions were 30℃ and the time was 48 h. In step 2, the mass ratio of modified aluminum hydroxide to ethanol aqueous solution was 1:80. In step 2, the mass ratio of polyurethane foam, dispersion, and polyphosphoric acid solution was 1:100:80. The mass fraction of ethanol aqueous solution was 60%. The mass fraction of polyphosphoric acid solution was 2.5%. In step 2, the ultrasonic dispersion conditions were 40 kHz and the time was 15 min. In step 2, the microwave reaction conditions were 1000 W and the time was 3 min. In step 2, the drying conditions were 60℃ and the time was 8 h.

[0074] Example 2: A method for preparing polyurethane foam based on halogen-free bio-based flame-retardant polyether polyols, comprising the following steps:

[0075] (1) Preparation of modified aluminum hydroxide:

[0076] Step A: Mix the amino coupling agent, ethanol, and deionized water to obtain a mixed solution. Mix aluminum hydroxide with the mixed solution, stir to react, wash, and dry to obtain aminated aluminum hydroxide. Step B: Mix cyanuric chloride and acetonitrile, stir evenly, add aminated aluminum hydroxide, microwave to react, wash, and dry to obtain modified aluminum hydroxide. In Step A, the mass ratio of amino coupling agent, ethanol, and deionized water is 1:13:18; the mass ratio of aluminum hydroxide to the mixed solution is 1:55; the stirring reaction conditions in Step A are: temperature 30℃, time 2.0h; the ratio of cyanuric chloride, acetonitrile, and aminated aluminum hydroxide in Step B is 20g:500mL:75g; the microwave reaction conditions in Step B are: power 900W, time 1.5min; the drying conditions are: temperature 48℃, time 11h.

[0077] (2) Preparation of double-bond bio-based polyether polyols:

[0078] A polyhydroxy compound and potassium hydroxide were mixed and dehydrated under a nitrogen atmosphere by evacuating to a vacuum of -0.1 MPa. Then, epoxidized soybean oil and allyl glycidyl ether were added, and the mixture was heated to obtain a double-bonded bio-based polyether polyol. The mass ratio of the polyhydroxy compound, potassium hydroxide, epoxidized soybean oil, and allyl glycidyl ether was 100:1.2:105:210. The dehydration conditions were: temperature 115℃, time 0.8 h; the heating reaction conditions were: temperature 115℃, time 1.2 h.

[0079] (3) Preparation of bio-based flame-retardant polyether polyols:

[0080] S1: Dimethyl methyl phosphate and diethylene glycol are mixed and heated to react, yielding a hydroxyl-terminated flame retardant; S2: Hydrogen-containing silicone oil, the hydroxyl-terminated flame retardant, and tributyltin oxide are mixed and heated under a nitrogen atmosphere to react, yielding a flame-retardant hydrogen-containing organosilicon; S3: Double-bond bio-based polyether polyol, flame-retardant hydrogen-containing organosilicon, and chloroplatinic acid solution are mixed and heated to react, yielding a bio-based flame-retardant polyether polyol; In S1, the molar ratio of dimethyl methyl phosphate to diethylene glycol is 1:2.0; In S1, the process conditions for the heating reaction are: temperature 140°C. The reaction conditions in S2 were: temperature 70℃, time 0.8h; in S2, the mass ratio of hydrogen-containing silicone oil, hydroxyl-terminated flame retardant, and tributyltin oxide was 30:10:0.4; in S2, the heating reaction conditions were: temperature 70℃, time 45min; in S3, the mass ratio of double-bonded bio-based polyether polyol, flame-retardant hydrogen-containing organosilicon, and chloroplatinic acid solution was 10:12:0.03; in S3, the chloroplatinic acid solution was prepared by mixing chloroplatinic acid and isopropanol at a mass ratio of 3:97; in S3, the heating reaction conditions were: temperature 105℃, time 2.0h.

[0081] (4) Preparation of polyurethane foam:

[0082] Step 1: Mix bio-based flame-retardant polyether polyol, catalyst, foaming agent, and stabilizer, stir evenly, let stand, then add isocyanate monomer, stir to foam and mature to obtain polyurethane foam; Step 2: Mix modified aluminum hydroxide with ethanol aqueous solution, ultrasonically disperse to obtain dispersion, immerse polyurethane foam in dispersion, press 15 times, remove and dry, then immerse in polyphosphoric acid solution, microwave reaction, remove and dry to obtain polyurethane foam; In Step 1, the mass ratio of bio-based flame-retardant polyether polyol, catalyst, foaming agent, and stabilizer is 100:0.20:1.5:1.5; The stirring and foaming process conditions in Step 1 are: The temperature was 43℃ ​​and the time was 4.5 min. In step 1, the curing conditions were 28℃ and the time was 44 h. In step 2, the mass ratio of modified aluminum hydroxide to ethanol aqueous solution was 1:65. In step 2, the mass ratio of polyurethane foam, dispersion, and polyphosphoric acid solution was 1:80:70. The mass fraction of ethanol aqueous solution was 40%, and the mass fraction of polyphosphoric acid solution was 2.0%. In step 2, the ultrasonic dispersion conditions were 30 kHz and the time was 10 min. In step 2, the microwave reaction conditions were 900 W and the time was 2 min. In step 2, the drying conditions were 50℃ and the time was 7 h.

[0083] Example 3: A method for preparing polyurethane foam based on halogen-free bio-based flame-retardant polyether polyols, comprising the following steps:

[0084] (1) Preparation of modified aluminum hydroxide:

[0085] Step A: Mix the amino coupling agent, ethanol, and deionized water to obtain a mixed solution. Mix aluminum hydroxide with the mixed solution, stir and react, wash and dry to obtain aminated aluminum hydroxide. Step B: Mix cyanuric chloride and acetonitrile, stir evenly, add aminated aluminum hydroxide, microwave reaction, wash and dry to obtain modified aluminum hydroxide. In Step A, the mass ratio of amino coupling agent, ethanol, and deionized water is 1:10:15; the mass ratio of aluminum hydroxide to the mixed solution is 1:50; the stirring reaction conditions in Step A are: temperature 25℃, time 1.5h; the ratio of cyanuric chloride, acetonitrile, and aminated aluminum hydroxide in Step B is 15g:500mL:60g; the microwave reaction conditions in Step B are: power 800W, time 1min; the drying conditions are: temperature 45℃, time 10h.

[0086] (2) Preparation of double-bond bio-based polyether polyols:

[0087] A polyhydroxy compound and potassium hydroxide were mixed and dehydrated under a nitrogen atmosphere by evacuating to a vacuum of -0.1 MPa. Then, epoxidized soybean oil and allyl glycidyl ether were added, and the mixture was heated to obtain a double-bonded bio-based polyether polyol. The mass ratio of the polyhydroxy compound, potassium hydroxide, epoxidized soybean oil, and allyl glycidyl ether was 100:1.0:100:200. The dehydration conditions were: temperature 110℃, time 0.5 h; the heating reaction conditions were: temperature 110℃, time 1.0 h.

[0088] (3) Preparation of bio-based flame-retardant polyether polyols:

[0089] S1: Dimethyl methyl phosphate and diethylene glycol are mixed and heated to react, yielding a hydroxyl-terminated flame retardant; S2: Hydrogen-containing silicone oil, the hydroxyl-terminated flame retardant, and tributyltin oxide are mixed and heated under a nitrogen atmosphere to react, yielding a flame-retardant hydrogen-containing organosilicon; S3: Double-bond bio-based polyether polyol, flame-retardant hydrogen-containing organosilicon, and chloroplatinic acid solution are mixed and heated to react, yielding a bio-based flame-retardant polyether polyol; In S1, the molar ratio of dimethyl methyl phosphate to diethylene glycol is 1:1.8; In S1, the process conditions for the heating reaction are: temperature 130°C. The reaction conditions in S2 were: temperature 60℃, time 0.6h; in S3, the mass ratio of hydrogen-containing silicone oil, hydroxyl-terminated flame retardant, and tributyltin oxide was 20:10:0.3; the heating reaction conditions in S2 were: temperature 60℃, time 25min; in S3, the mass ratio of double-bonded bio-based polyether polyol, flame-retardant hydrogen-containing organosilicon, and chloroplatinic acid solution was 10:11:0.02; the chloroplatinic acid solution in S3 was prepared by mixing chloroplatinic acid and isopropanol at a mass ratio of 1:99; the heating reaction conditions in S3 were: temperature 100℃, time 1.8h.

[0090] (4) Preparation of polyurethane foam:

[0091] Step 1: Mix bio-based flame-retardant polyether polyol, catalyst, foaming agent, and stabilizer, stir evenly, let stand, then add isocyanate monomer, stir to foam, and mature to obtain polyurethane foam; Step 2: Mix modified aluminum hydroxide with ethanol aqueous solution, ultrasonically disperse to obtain dispersion, immerse the polyurethane foam in the dispersion, press 10 times, remove and dry, then immerse in polyphosphoric acid solution, microwave reaction, remove and dry to obtain polyurethane foam; In Step 1, the mass ratio of bio-based flame-retardant polyether polyol, catalyst, foaming agent, and stabilizer is 100:0.15:1.0:1.0; In Step 1, the stirring and foaming process conditions are as follows: The curing process conditions in step 1 are: temperature 40℃, time 4min; in step 2, the curing process conditions are: 25℃, time 40h; in step 2, the mass ratio of modified aluminum hydroxide to ethanol aqueous solution is 1:50; in step 2, the mass ratio of polyurethane foam, dispersion, and polyphosphoric acid solution is 1:50:60; the mass fraction of ethanol aqueous solution is 20%; the mass fraction of polyphosphoric acid solution is 1.5%; in step 2, the ultrasonic dispersion process conditions are: frequency 20kHz, time 5min; in step 2, the microwave reaction process conditions are: power 800W, time 1min; in step 2, the drying process conditions are: temperature 40℃, time 6h.

[0092] Comparative Example 1: Compared with Example 1, the polyurethane foam was not impregnated, and all other conditions remained the same as in Example 1.

[0093] Comparative Example 2: Compared with Example 1, the bio-based flame-retardant polyether polyol was replaced with polyether polyol, and the other conditions remained the same as in Example 1.

[0094] Comparative Example 3: Compared with Example 1, the polyurethane foam was not impregnated, and the bio-based flame-retardant polyether polyol was replaced with polyether polyol. All other conditions remained the same as in Example 1.

[0095] Experiment: The flame retardancy and resilience of the polyurethane foams obtained in Examples 1-3 and Comparative Examples 1-3 were tested.

[0096] Flame retardancy test: Refer to GB / T 2406.3-2022 to test the oxygen index of polyurethane foam to characterize its flame retardant performance;

[0097] Resilience test: Refer to ATSM-D-3574-H to test the resilience of polyurethane foam in order to characterize its resilience.

[0098]

[0099] Based on the data in the table above, the following conclusions can be drawn:

[0100] Compared with Example 1, Comparative Example 1 did not perform impregnation treatment on the polyurethane foam, and its flame retardant performance decreased. This is because without impregnation treatment, a flame retardant protective layer cannot be formed on the surface of the polyurethane foam, thus reducing its flame retardancy.

[0101] Compared with Example 1, Comparative Example 2 replaced the bio-based flame-retardant polyether polyol with polyether polyol, and its flame retardancy and resilience both decreased. This is because ordinary polyether polyol does not have flame retardant ability and its molecular weight is lower than that of the bio-based flame-retardant polyether polyol prepared in this application, so its resilience is lower.

[0102] Compared with Example 1, the flame retardancy and resilience of Comparative Example 3 decreased significantly. It can be seen that the preparation and impregnation treatment of bio-based flame retardant polyether polyol in this application can promote the comprehensive improvement of the flame retardancy and resilience of the prepared polyurethane foam.

[0103] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

Claims

1. A method for preparing polyurethane foam based on halogen-free bio-based flame-retardant polyether polyols, characterized in that: Includes the following steps: Step 1: Mix bio-based flame retardant polyether polyol, catalyst, foaming agent and stabilizer, stir evenly, let stand, then add isocyanate monomer, stir to foam and mature to obtain polyurethane foam. Step 2: Mix modified aluminum hydroxide with an aqueous ethanol solution, ultrasonically disperse to obtain a dispersion, immerse polyurethane foam in the dispersion and press it 10-20 times, take it out and dry it, then immerse it in a polyphosphoric acid solution, microwave it, take it out and dry it to obtain polyurethane foam. In step 1, the preparation process of the bio-based flame-retardant polyether polyol is as follows: S1: Mix dimethyl methyl phosphate and diethylene glycol, and heat to react to obtain a hydroxyl-terminated flame retardant; S2: Mix hydrogen-containing silicone oil, hydroxyl-terminated flame retardant and tributyltin oxide, and heat to react under nitrogen atmosphere to obtain flame-retardant hydrogen-containing organosilicon. S3: Mix double-bond bio-based polyether polyol, flame-retardant hydrogen-containing organosilicon, and chloroplatinic acid solution, and heat to react to obtain bio-based flame-retardant polyether polyol. In step 2, the modified aluminum hydroxide is obtained by the following process: Step A: Mix the amino coupling agent, ethanol, and deionized water to obtain a mixture. Mix aluminum hydroxide with the mixture, stir to react, wash, and dry to obtain aminated aluminum hydroxide. Step B: Mix cyanuric chloride and acetonitrile, stir well, add aminated aluminum hydroxide, microwave reaction, wash and dry to obtain modified aluminum hydroxide; The preparation process of the double-bond bio-based polyether polyol is as follows: A polyhydroxy compound and potassium hydroxide were mixed and dehydrated under a nitrogen atmosphere by evacuating to a vacuum of -0.1 MPa. Then, epoxidized soybean oil and allyl glycidyl ether were added and the mixture was heated to obtain a double-bonded bio-based polyether polyol.

2. The method for preparing polyurethane foam based on halogen-free bio-based flame-retardant polyether polyols according to claim 1, characterized in that: In S1, the molar ratio of dimethyl methyl phosphate to diethylene glycol is 1:(1.8~2.2).

3. The method for preparing polyurethane foam based on halogen-free bio-based flame-retardant polyether polyols according to claim 1, characterized in that: In S2, the mass ratio of hydrogen-containing silicone oil, hydroxyl-terminated flame retardant, and tributyltin oxide is (20~40):10:(0.3~0.5).

4. The method for preparing polyurethane foam based on halogen-free bio-based flame-retardant polyether polyol according to claim 1, characterized in that: In S3, the mass ratio of double-bonded bio-based polyether polyol, flame-retardant hydrogen-containing organosilicon, and chloroplatinic acid solution is 10:(11~13):(0.02~0.04).

5. The method for preparing polyurethane foam based on halogen-free bio-based flame-retardant polyether polyol according to claim 1, characterized in that: In step 2, the microwave reaction process conditions are: power 800~1000W, time 1~2min.

6. The method for preparing polyurethane foam based on halogen-free bio-based flame-retardant polyether polyols according to claim 1, characterized in that: In step 1, the mass ratio of bio-based flame-retardant polyether polyol, catalyst, foaming agent, and stabilizer is 100:(0.15~0.25):(1.0~2.0):(1.0~2.0).

7. A polyurethane foam based on halogen-free bio-based flame-retardant polyether polyol, characterized in that: The preparation method according to any one of claims 1 to 6 is used.

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