Polyurethane foam with good thermal insulation property and preparation method thereof

[0027] In one embodiment, the preparation method of the soybean oil polyol includes the following steps:

[0028] (1) Add soybean oil and maleic anhydride into a four-necked flask, heat to 190-210°C, and react for 2 to 3 hours to obtain the intermediate maleic anhydride modified soybean oil;

[0029] (2) Add maleic anhydride modified soybean oil, diethylene glycol and KOH into a four-necked flask, heat it to 190~220℃, react for 5~6h to obtain crude soybean oil polyol;

[0030] (3) Add crude soybean oil polyol into a four-necked flask, remove unreacted diethylene glycol through multiple washings and liquid separation; add 3wt% water and 98% phosphoric acid to neutralize KOH, 0.3wt % Magnesium silicate adsorbent, the water is removed by vacuum distillation, and the adsorbent and potassium salt are removed by suction filtration.

[0031] Preferably, the maleic anhydride accounts for 0.25 to 0.4 wt% of soybean oil; more preferably, the maleic anhydride accounts for 0.34 wt% of soybean oil.

[0032] Preferably, the weight ratio of diethylene glycol to soybean oil is (1 to 1.5):1; more preferably, the weight ratio of diethylene glycol to soybean oil is 1:1.

[0033] Preferably, the KOH accounts for 0.04-0.09 wt% of the maleic anhydride modified soybean oil; more preferably, the KOH accounts for 0.06 wt% of the maleic anhydride modified soybean oil.

[0034] In a preferred embodiment, the preparation method of the soybean oil polyol includes the following steps:

[0035] (1) Put soybean oil and maleic anhydride into a four-necked flask, place the four-necked flask in a heating mantle, install stirring, condensate water, thermometer and nitrogen protection. Turn on the nitrogen protection, condensate water and stirring, heat the heating mantle to 210°C, react for 3 hours to obtain the intermediate maleic anhydride modified soybean oil;

[0036] (2) Add maleic anhydride modified soybean oil, diethylene glycol and KOH into a four-necked flask, place the mixture in a heating mantle, install stirring, condensate water, thermometer and nitrogen protection, where the condensate water should be installed horizontally. In order to drain the water produced during the reaction. Turn on nitrogen protection, condensate water and stirring, heat the heating mantle to 220°C, react for 6 hours to obtain crude soybean oil polyol;

[0037] (3) Add crude soybean oil polyol in a four-necked flask, remove unreacted diethylene glycol through multiple washings and liquid separation; add 3wt% water and 98w% phosphoric acid to neutralize KOH, 0.3wt % Magnesium silicate adsorbent, the water is removed by vacuum distillation, and the adsorbent and potassium salt are removed by suction filtration.

[0038] Polyether polyol

[0039] Polyether polyol (abbreviated as polyether) is composed of initiators (compounds containing active hydrogen groups) and ethylene oxide (EO), propylene oxide (PO), butylene oxide (BO), etc. in the catalyst It is obtained by addition polymerization reaction. The largest polyether output is glycerin (glycerol) as the initiator and epoxide (usually propylene oxide and ethylene oxide are used together), by changing the feeding method of propylene oxide and ethylene oxide (mixing Adding or adding separately), adding amount ratio, adding order and other conditions, produce various general polyether polyols.

[0040] In one embodiment, the polyether polyol has a functionality of 2 to 3 and a weight average molecular weight of 500 to 700.

[0041] The applicant found that the air permeability of polyurethane foam prepared by using other plant polyols is poor, while the air permeability performance of using soybean oil polyol is improved. The possible reason is that silica aerogels and alumina/silica aerogels are concentrated at the junction of the foam in the polyurethane foam structure, which has a certain obstructive effect on the pores in the structure, while many fats in soybean oil polyols The side chain of the group does not participate in the reaction and can cause certain damage to the cells, thereby increasing the air permeability. However, the air permeability and the anti-vibration performance go against each other. After the increase in the air permeability, the distance between the molecules increases, resulting in insufficient vibration energy absorption, thereby reducing the anti-vibration performance of polyurethane. The applicant unexpectedly discovered in experiments that certain restrictions on the functionality and weight average molecular weight of the polyether polyol will significantly increase the vibration-proof performance of the polyurethane foam. The possible reason is that polyether polyols with a weight average molecular weight of 500-700, soybean oil polyols and polymethylene polyphenyl isocyanate after cross-linking reduce the dangling fatty chains in soybean oil polyols, and increase the cross-linking of polyurethane. Associated density, the energy of vibration is offset by the interaction between the molecular chain segments and the friction between the chain segments after being subjected to energy vibration, resulting in energy dissipation and achieving the effect of vibration prevention. If the weight average molecular weight of the applicant is too small, the air permeability will be reduced. If the weight average molecular weight is too large, the anti-vibration effect will not be achieved, and the elasticity will be reduced. The possible reason is that the hard segment of polyurea formed by isocyanate and water is partially mixed in the soft segment. Resulting in reduced elasticity.

[0042] Aerogel

[0043] Aerogel, also known as xerogel. When most of the solvent is removed from the gel, the liquid content in the gel is much less than the solid content, or the medium in the spatial network structure of the gel is gas and the appearance is solid. This is a dry gel. It is called aerogel. Such as gelatin, gum arabic, silica gel, hair, nails, etc. Aerogels also have the properties of gels, that is, they have swelling, thixotropic, and de-sizing effects.

[0044] In one embodiment, the aerogel includes silica aerogel and alumina/silica aerogel.

[0045] Preferably, the preparation method of the silica aerogel includes: placing 40 mL of dilute hydrochloric acid with a concentration of 0.15 mol/L, 12.6 mL of tetraethyl orthosilicate and 10 mL of absolute ethanol in a beaker and uniformly mixing, and sealing the beaker , Stir at room temperature for 10-13h. Then add 0.5mL 5wt% HF solution dropwise to the sol, stop stirring after 10-20min, let stand for 10-13h, then soak and wash once with deionized water, and exchange again with absolute ethanol three times, each time for 5-6h . After that, it was exchanged three times with 100 mL of n-hexane, and soaked in a mixed liquid of 4.0 mL of hexamethyldisilazane and 20 mL of n-hexane for 10-12 hours. Finally, the residual silane and reactants in the gel were washed with n-hexane, dried at room temperature for 12 hours, and dried in an oven at 60°C for 6 hours to obtain.

[0046] More preferably, the preparation method of the silica aerogel includes: placing 40 mL of dilute hydrochloric acid with a concentration of 0.15 mol/L, 12.6 mL of tetraethyl orthosilicate and 10 mL of absolute ethanol in a beaker and uniformly mixing, and sealing Beaker, stirring at room temperature for 12h. After that, 0.5 mL of 5wt% HF solution was added dropwise to the sol with a needle, stirring was stopped after 15 minutes, and the mixture was allowed to stand for 12 hours. Then, it was soaked and washed with 100 mL of deionized water once, and exchanged with 100 mL of absolute ethanol for three times each time for 6 hours. After that, it was exchanged three times with 100 mL of n-hexane, and soaked in a mixed liquid of 4.0 mL of hexamethyldisilazane and 20 mL of n-hexane for 12 hours. Finally, the residual silane and reactants in the gel were washed with n-hexane, dried at room temperature for 12 hours, and dried in an oven at 60°C for 6 hours to obtain.

[0047] In one embodiment, the alumina/silica aerogel is modified alumina/silica aerogel; the modified alumina/silica aerogel is amino modified Of alumina/silica aerogel.

[0048] In one embodiment, the raw materials for preparing the amino-modified alumina/silica aerogel include chitosan, lauryl sulfate triethanolamine salt, aluminum chloride, and tetraethyl orthosilicate; preferably The weight ratio of the chitosan, lauryl sulfate triethanolamine salt, aluminum chloride, and tetraethyl orthosilicate is (1~1.5):1:(15-22):(20-25); More preferably, the weight ratio of the chitosan, lauryl sulfate triethanolamine salt, aluminum chloride, and tetraethylorthosilicate is 1.2:1:20:23.

[0049] In one embodiment, the preparation method of the amino-modified alumina/silica aerogel includes: weighing chitosan in a beaker, dissolving it with 50 mL of dilute hydrochloric acid with a concentration of 0.15 mol/L, and pumping A clear solution was filtered. Add lauryl sulfate triethanolamine salt, aluminum chloride, tetraethyl orthosilicate and 10 mL of absolute ethanol slowly to the above clear solution, seal the beaker, and stir for 10 to 13 hours. Then, 1 mL of 5 wt% HF solution was added dropwise to the sol, stirring was stopped after 15 minutes, and the wet gel was obtained by standing for 10 to 13 hours. The gel in the beaker was immersed and washed once with 150 mL of deionized water, and then exchanged with 150 mL of absolute ethanol three times for 6 hours each time to obtain a pretreated composite gel. Take 6.0 mL of epichlorohydrin and 3 drops of perchloric acid (70 wt%), mix them with 70 mL of absolute ethanol, and add them to the pretreated composite gel beaker. After standing at room temperature for 12 hours, the residual epichlorohydrin and perchloric acid in the gel were washed with absolute ethanol. Then add 3.0mL ethylenediamine and 50mL anhydrous ethanol mixed solution, and keep it in a water bath at 50℃ for 12h. Wash with absolute ethanol to obtain amino-modified alumina/silica wet gel. After that, it was exchanged three times with 150 mL of n-hexane, and immersed in a mixed liquid of 7.0 mL of hexamethyldisilazane and 30 mL of n-hexane for 12 hours. Finally, the residual silane and reactants in the gel were washed with n-hexane, dried at room temperature for 12 hours, and dried in an oven at 60°C for 6 hours to obtain.

[0050] In a preferred embodiment, the preparation method of the amino-modified alumina/silica aerogel includes: weighing 0.6 g of chitosan in a beaker, and using 50 mL of dilute with a concentration of 0.15 mol/L. The hydrochloric acid was dissolved and filtered with suction to obtain a clear solution. 0.5 g of lauryl alcohol sulfate triethanolamine salt, 10 g of aluminum chloride, 12.6 mL of tetraethyl orthosilicate, and 10 mL of absolute ethanol were slowly added to the above clear solution, the beaker was sealed, and the mixture was stirred at room temperature for 12 hours. Then, 1 mL of 5 wt% HF solution was added dropwise to the sol with a needle tube, stirring was stopped after 15 minutes, and the wet gel was obtained by standing for 12 hours. The gel in the beaker was immersed and washed once with 150 mL of deionized water, and then exchanged with 150 mL of absolute ethanol three times for 6 hours each time to obtain a pretreated composite gel. Take 6.0 mL of epichlorohydrin and 3 drops of perchloric acid (70% by weight), mix them with 70 mL of absolute ethanol, and add them to the pretreated composite gel beaker. After standing at room temperature for 12 hours, the residual epichlorohydrin and perchloric acid in the gel were washed with absolute ethanol. Then add 3.0mL ethylenediamine and 50mL anhydrous ethanol mixed solution, and keep it in a water bath at 50℃ for 12h. Wash with absolute ethanol to obtain amino-modified alumina/silica wet gel. After that, it was exchanged three times with 150 mL of n-hexane, and immersed in a mixed liquid of 7.0 mL of hexamethyldisilazane and 30 mL of n-hexane for 12 hours. Finally, the residual silane and reactants in the gel were washed with n-hexane, dried at room temperature for 12 hours, and dried in an oven at 60°C for 6 hours to obtain.

[0051] In one embodiment, the weight ratio of the silica aerogel and the modified alumina/silica aerogel is (3-6):1; preferably, the silica aerogel The weight ratio of glue and modified alumina/silica aerogel is 5:1.

[0052] The applicant found in the research that when silica aerogel and alumina/silica aerogel exist simultaneously, the heat resistance of polyurethane foam can be significantly improved. Only silica aerogel has better heat resistance. Poor. The possible reason is that silica aerogel is mainly concentrated at the junction of the foam in the polyurethane foam structure, which can reduce the solid conduction of polyurethane. However, silica aerogel is transparent to infrared rays with a wavelength of 3-8 microns. However, the thermal conductivity of the aerogel rises sharply under high temperature conditions, and it is also possible that the aerogel has agglomerated at high temperatures, which limits the use of polyurethane foam under high temperature conditions. Alumina/silica aerosol The addition of glue can effectively improve the heat resistance. The possible reason is that the addition of alumina prevents the transmission of infrared rays during the preparation of the aerogel. However, the applicant unexpectedly found that simply adding alumina in the preparation process of polyurethane foam would not improve the heat resistance significantly, and the thermal insulation performance would also be greatly reduced. The possible reason is that on the one hand, the alumina aggregates together and cannot effectively prevent the penetration of infrared rays. However, on the other hand, alumina may be coated in silica aerogel, making the alumina unable to communicate with the external environment. At the same time, the interaction between alumina and silica aerogel reduces the specific surface area and porosity of silica aerogel, which affects air permeability.

[0053] The applicant unexpectedly found that modifying the alumina/silica aerogel improves the sound absorption and noise reduction performance of the polyurethane foam. The possible reason is that the modified alumina/silica aerogel makes it easier to generate cells around the aerogel. The amino groups in the amino-modified alumina/silica aerogel can also affect the foaming. The carbon dioxide gas has an adsorption effect, and the compatibility of the amino group and the polyurethane matrix is ​​improved. In this way, the polyurethane matrix is ​​surrounded by the aerogel, which improves the distribution of the foaming gas in the polyurethane matrix, and the cells are more uniform. It is not easy to communicate with each other, and the closed cell rate increases, thereby further improving the sound absorption and noise reduction performance of the polyurethane foam.

[0054] The applicant discovered during the experiment that the weight ratio of silica aerogel and modified alumina/silica aerogel must be strictly controlled. If the content of silica aerogel is too high, the high temperature resistance will be poor and oxidation If the content of aluminum/silica is too high, the resilience will be poor. The possible reason is that the existence of modified alumina/silica aerogel makes the pore distribution of aerogels not concentrated, and the difference in pore size is large. Increased, it is easy to reach the yield strength, and it is not easy to return to the original shape.

[0055] In one embodiment, the weight ratio of the aerogel and the vegetable oil polyol is 1: (4-6); preferably, the weight ratio of the aerogel and the vegetable oil polyol is 1:5.

[0056] The applicant found that controlling the weight ratio of aerogel to vegetable oil polyol during the preparation of polyurethane foam can improve the water resistance and mechanical properties of the polyurethane foam. The possible reason is that the hydroxyl groups in the vegetable oil polyols form hydrogen bonds with the amino groups in the aerogel to make them more tightly bound and reduce the pores. At the same time, in the process of forming polyurethane, the isocyanate groups contained in the vegetable oil are in the aerogel. The amine reacts to form a urea group, which increases the cross-linking inside the foam. If the content of aerogel is too high, the mechanical properties will decrease. It may be that the hydroxyl groups in the aerogel and the hydroxyl groups of the polyol lead to uneven distribution of the final polyurethane structure and uneven stress; the applicant found that when the content of aerogel is too high However, the water resistance will decrease instead. The possible reason is that during the modification of the amino group of silica in the alumina/silica aerogel, it will corrode the structure of the gel skeleton. The weak skeleton is prone to collapse, causing the pore size to increase. , Make the water resistance decrease; if the content of aerogel is too low, the water resistance performance will decrease. The possible reason is that the Si-O-Si and Al-O-Si groups of the aerogel are not enough to block the erosion of water molecules. The content of vegetable oil polyol is too high, the mechanical properties are reduced, and the water resistance is reduced. The possible reason is that the force between the molecules is increased or the weak acidity of the vegetable oil polyol is not conducive to the reaction, and the regularity of the generated molecules is reduced. Too many fatty chains in vegetable oil polyols coat the aerogel and affect the function of the aerogel; if the content of vegetable oil polyol is too low, the elasticity decreases. The possible reason is that the polyol is not enough to provide hydroxyl groups. The aerogel will react with the isocyanate, resulting in an increase in the hard segment of the molecule.

[0057] Foaming agent

[0058] The so-called foaming agent is a substance that makes the target substance pores. It can be divided into three categories: chemical foaming agent, physical foaming agent and surfactant. Chemical blowing agents are those compounds that can release carbon dioxide and nitrogen gas after being decomposed by heating, and form pores in the polymer composition; physical blowing agents are the changes in the physical form of the foam pores through a certain substance , Which is formed by the expansion of compressed gas, the volatilization of liquid or the dissolution of solids; foaming agents have high surface activity, can effectively reduce the surface tension of the liquid, and arrange the double electron layer on the surface of the liquid film to surround the air , To form bubbles, and then a single bubble forms a foam.

[0059] In one embodiment, the blowing agent is selected from trans-1-chloro-3,3,3-trifluoropropene, 1,1,1,3,3-pentafluoropropane, 1,1,1 , At least one of 4,4,4-hexafluorobutene; preferably, the blowing agent includes 1,1,1,4,4,4-hexafluorobutene, CAS: 692-49-9 .

[0060] Foam stabilizer

[0061] Foam stabilizers have been proven to be one of the key components in foam production.

[0062] They make the pores fine and uniform. When the system is in the low-viscosity stage, it stabilizes the pore wall and the pores can grow to a thickness suitable for opening, creating conditions for the final opening. The type of foam is different, the type of stabilizer used is also different, its main function is to nucleate and emulsify each component in the formula. The compatibility of the various components in the foam formulation is not good, so a stabilizer with strong emulsifying ability is needed to emulsify and mix them. The soft foam is made of water as a blowing agent. The reaction rate of water and isocyanate is higher than that of isocyanate and polyol. Therefore, a large amount of solid polyurea is formed in the initial stage of foaming. It is a defoaming agent that can help open cells and Blasthole. Opening and popping are the stages when soft foam foaming must occur, otherwise, closed cells will occur and the foam performance will decrease. But the opening and popping must occur when the foaming reaction and the gel reaction are basically completed and reach equilibrium. That is, when the foam rises to the highest point and the strength of the foam can support its own weight, otherwise it will cause the foam to collapse. Therefore, another important function of the soft steam foam stabilizer is that it can dissolve the polyurea formed by the reaction in the early stage of foaming and can help open and burst holes in the late stage of foaming.

[0063] The foam stabilizer can reduce the surface tension of the polyurethane raw material mixture, and prevents the thermodynamically unstable state of the foam from appearing through the surface tension during the foam rise to maturation.

[0064] In one embodiment, the foam stabilizer is a silicone foam stabilizer; preferably, the silicone foam stabilizer is silicone oil.

[0065] catalyst

[0066] In a chemical reaction, a substance that can change the chemical reaction rate (increase or decrease) of the reactants without changing the chemical balance, and whose quality and chemical properties have not changed before and after the chemical reaction is called a catalyst (solid catalyst is also called a catalyst). According to statistics, more than 90% of industrial processes use catalysts, such as chemical, petrochemical, biochemical, and environmental protection. There are many types of catalysts, which can be divided into liquid catalysts and solid catalysts according to their states; according to the phase state of the reaction system, they are divided into homogeneous catalysts and heterogeneous catalysts. Homogeneous catalysts include acid, alkali, soluble transition metal compounds and peroxide catalysts. Catalysts occupy an extremely important position in the modern chemical industry. For example, iron catalysts are used in the production of synthetic ammonia, vanadium catalysts are used in the production of sulfuric acid, and different catalysts are used in the production of three major synthetic materials such as the polymerization of ethylene and rubber from butadiene. .

[0067] In one embodiment, the catalyst is selected from N,N-dimethylcyclohexylamine, N-ethylmorpholine, N-methylmorpholine, N,N-diethylpiperazine, triethanolamine, At least one of DMEA, T-9, T-12; preferably, the catalyst includes triethanolamine and T-9; further preferably, the weight ratio of triethanolamine and T-9 is (1 to 3) :1; More preferably, the weight ratio of the triethanolamine and T-9 is 1:1; the triethanolamine CAS: 102-71-6, and the T-9 CAS: 301-10-0.

[0068] water

[0069] The reaction of isocyanate and water is one of the very important reactions in the process of synthesizing polyurethane foam, and CO is produced in the reaction 2 Gas, so as to obtain uniform cells. The reaction speed of isocyanate and water has an important influence on the performance of polyurethane foam. Therefore, the reaction speed of isocyanate and water is generally adjusted by adding a catalyst to obtain polyurethane foam with excellent performance. It is precisely because isocyanate can react with water, it should avoid contact with water in the air during its storage.

[0070] Polyisocyanate

[0071] Polyisocyanates are one of the main raw materials of polyurethane adhesives. The polyisocyanates used in the manufacture of polyurethane adhesives include diisocyanates, triisocyanates and their modified bodies, among which diisocyanates are the most common. Among polyisocyanates, toluene diisocyanate uses low-priced toluene and benzene as raw materials, so it develops rapidly and is dominant.

[0072] In one embodiment, the polyisocyanate is selected from hexamethylene diisocyanate, isophorone diisocyanate, 1,6-hexamethylene diisocyanate, polymethylene polyphenyl isocyanate, diphenylmethane diisocyanate , At least one of xylylene diisocyanate, naphthalene-1,5-diisocyanate; preferably, the polyisocyanate includes polymethylene polyphenyl isocyanate, and the polymethylene polyphenyl isocyanate CAS : 9016-87-9.

[0073] Flame retardant

[0074] Flame retardants, functional additives that endow flammable polymers with flame retardancy, are mainly designed for the flame retardancy of polymer materials; there are many types of flame retardants, which are divided into additive flame retardants and reactions according to the method of use Type flame retardant.

[0075] The additive flame retardant is added to the polymer by mechanical mixing method to make the polymer flame retardant. At present, the additive flame retardant mainly includes organic flame retardant, inorganic flame retardant, halogen flame retardant (organic Chloride and organic bromide) and non-halogen flame retardants. Organic flame retardants are some flame retardants represented by bromine, phosphorus nitrogen, nitrogen, red phosphorus and compounds. Inorganic flame retardants are mainly antimony trioxide, magnesium hydroxide, aluminum hydroxide, silicon, etc. Flame retardant system.

[0076] Reactive flame retardants are used as a monomer to participate in the polymerization reaction, so the polymer itself contains flame retardant components. Its advantage is that it has less impact on the performance of polymer materials and has long-lasting flame retardancy.

[0077] In one embodiment, the flame retardant is selected from at least one of ammonium dihydrogen phosphate, fly ash, expandable graphite, and aluminum hydroxide; preferably, the flame retardant includes expandable graphite.

[0078] The second aspect of the present invention provides a method for preparing the polyurethane foam, which includes the following steps:

[0079] (1) Add polyester polyol, polyether polyol, foaming agent, water, foam stabilizer, catalyst and aerogel into a beaker, stir evenly to obtain component A;

[0080] (2) Polyisocyanate is component B, and the temperature of component A and component B is controlled at 20-30℃; mix components A and B, stir evenly, and quickly pour the mixture of component A and component B Put it into the foaming box and get it.

[0081] In one embodiment, the preparation method of the polyurethane foam includes the following steps:

[0082] (1) Add polyester polyol, polyether polyol, foaming agent, water, foam stabilizer, catalyst, aerogel, and flame retardant into the beaker, and stir them with 3000 rpm automatic stirring Obtain component A uniformly;

[0083] (2) Polyisocyanate is the B component, and the temperature of the A and B components is controlled at 25°C; mix the A and B components, stir them for 5 seconds with 3000 rpm automatic stirring, and quickly mix the A Pour the mixture of sub-component and B-component into the foaming box and get it.

[0086] Example 1

[0087] Example 1 of the present invention provides a polyurethane foam with good thermal insulation. In parts by weight, the raw materials for preparing the polyurethane foam include 60 parts of polyester polyol, 15 parts of polyether polyol, 15 parts of aerogel, and 5 parts by weight. Parts foaming agent, 0.5 parts foam stabilizer, 0.5 parts catalyst, 0.75 parts water, 65 parts polyisocyanate, 2.5 parts flame retardant.

[0088] The polyester polyol is vegetable oil polyol; the vegetable oil polyol is soybean oil polyol; the polyether polyol is purchased from Guangzhou Yinghong Chemical Co., Ltd., the model is Puranol D204; the aerogel includes two Silica aerogel and amino-modified alumina/silica aerogel; the weight ratio of said silica aerogel and amino-modified alumina/silica aerogel is 3:1; The blowing agent is 1,1,1,4,4,4-hexafluorobutene; the foam stabilizer is silicone oil; the catalyst includes triethanolamine and T-9; the triethanolamine and T-9 The weight ratio is 1:1; the polyisocyanate is polymethylene polyphenyl isocyanate; the flame retardant is expandable graphite.

[0089] The preparation method of the soybean oil polyol includes the following steps:

[0090] (1) Put soybean oil and maleic anhydride into a four-necked flask, place the four-necked flask in a heating mantle, install stirring, condensate water, thermometer and nitrogen protection. Turn on the nitrogen protection, condensate water and stirring, heat the heating mantle to 210°C, react for 3 hours to obtain the intermediate maleic anhydride modified soybean oil;

[0091] (2) Add maleic anhydride modified soybean oil, diethylene glycol and KOH into a four-necked flask, place the mixture in a heating mantle, install stirring, condensate water, thermometer and nitrogen protection, where the condensate water should be installed horizontally. In order to drain the water produced during the reaction. Turn on nitrogen protection, condensate water and stirring, heat the heating mantle to 220°C, react for 6 hours to obtain crude soybean oil polyol;

[0092] (3) Add crude soybean oil polyol in a four-necked flask, remove unreacted diethylene glycol through multiple washings and liquid separation; add 3wt% water and 98w% phosphoric acid to neutralize KOH, 0.3wt % Magnesium silicate adsorbent, the water is removed by vacuum distillation, and the adsorbent and potassium salt are removed by suction filtration.

[0093] The maleic anhydride accounts for 0.34 wt% of soybean oil; the weight ratio of diethylene glycol to soybean oil is 1:1; and the KOH accounts for 0.06 wt% of maleic anhydride modified soybean oil.

[0094] The preparation method of the silica aerogel includes: placing 40 mL of dilute hydrochloric acid with a concentration of 0.15 mol/L, 12.6 mL of tetraethyl orthosilicate, and 10 mL of absolute ethanol in a beaker and uniformly mixing, sealing the beaker, and at room temperature Stir for 12h. After that, 0.5 mL of 5wt% HF solution was added dropwise to the sol with a needle, stirring was stopped after 15 minutes, and the mixture was allowed to stand for 12 hours. Then, it was soaked and washed with 100 mL of deionized water once, and exchanged with 100 mL of absolute ethanol for three times each time for 6 hours. After that, it was exchanged three times with 100 mL of n-hexane, and soaked in a mixed liquid of 4.0 mL of hexamethyldisilazane and 20 mL of n-hexane for 12 hours. Finally, the residual silane and reactants in the gel were washed with n-hexane, dried at room temperature for 12 hours, and dried in an oven at 60°C for 6 hours to obtain.

[0095] The preparation method of the amino-modified alumina/silica aerogel includes: weighing 0.6 g of chitosan in a beaker, dissolving it with 50 mL of dilute hydrochloric acid with a concentration of 0.15 mol/L, and filtering with suction to obtain a clear solution. 0.5 g of lauryl alcohol sulfate triethanolamine salt, 10 g of aluminum chloride, 12.6 mL of tetraethyl orthosilicate, and 10 mL of absolute ethanol were slowly added to the above clear solution, the beaker was sealed, and the mixture was stirred at room temperature for 12 hours. Then, 1 mL of 5 wt% HF solution was added dropwise to the sol with a needle tube, stirring was stopped after 15 minutes, and the wet gel was obtained by standing for 12 hours. The gel in the beaker was immersed and washed once with 150 mL of deionized water, and then exchanged with 150 mL of absolute ethanol three times for 6 hours each time to obtain a pretreated composite gel. Take 6.0 mL of epichlorohydrin and 3 drops of perchloric acid (70% by weight), mix them with 70 mL of absolute ethanol, and add them to the pretreated composite gel beaker. After standing at room temperature for 12 hours, the residual epichlorohydrin and perchloric acid in the gel were washed with absolute ethanol. Then add 3.0mL ethylenediamine and 50mL anhydrous ethanol mixed solution, and keep it in a water bath at 50℃ for 12h. Wash with absolute ethanol to obtain amino-modified alumina/silica wet gel. After that, it was exchanged three times with 150 mL of n-hexane, and immersed in a mixed liquid of 7.0 mL of hexamethyldisilazane and 30 mL of n-hexane for 12 hours. Finally, the residual silane and reactants in the gel were washed with n-hexane, dried at room temperature for 12 hours, and dried in an oven at 60°C for 6 hours to obtain.

[0096] The preparation method of the polyurethane foam includes the following steps:

[0097] (1) Add polyester polyol, polyether polyol, foaming agent, water, foam stabilizer, catalyst, aerogel, and flame retardant into the beaker, and stir them with 3000 rpm automatic stirring Obtain component A uniformly;

[0098] (2) Polyisocyanate is the B component, and the temperature of the A and B components is controlled at 25°C; mix the A and B components, stir them for 5 seconds with 3000 rpm automatic stirring, and quickly mix the A Pour the mixture of sub-component and B-component into the foaming box and get it.

[0099] Example 2

[0100] Example 2 of the present invention provides a polyurethane foam with good thermal insulation. The raw materials for preparing the polyurethane foam include 60 parts by weight of polyester polyol, 35 parts of polyether polyol, 10 parts of aerogel, and 10 parts by weight. Parts foaming agent, 2 parts foam stabilizer, 1 part catalyst, 1.6 parts water, 75 parts polyisocyanate; 5 parts flame retardant.

[0101] The polyester polyol is a vegetable oil polyol; the vegetable oil polyol is a soybean oil polyol; the polyether polyol is purchased from Guangzhou Yinghong Chemical Co., Ltd., the model is Puranol G307; the aerogel includes two Silica aerogel and amino-modified alumina/silica aerogel; the weight ratio of said silica aerogel and amino-modified alumina/silica aerogel is 6:1; The blowing agent is 1,1,1,4,4,4-hexafluorobutene; the foam stabilizer is silicone oil; the catalyst includes triethanolamine and T-9; the triethanolamine and T-9 The weight ratio is 3:1; the polyisocyanate is polymethylene polyphenyl isocyanate; the flame retardant is expandable graphite.

[0102] The specific implementation of the preparation method of the soybean oil is the same as in Example 1.

[0103] The specific implementation of the method for preparing the amino-modified alumina/silica aerogel is the same as that of Example 1.

[0104] The specific implementation of the method for preparing the silica aerogel is the same as that of Example 1.

[0105] The specific implementation of the preparation method of the polyurethane foam is the same as that of Example 1.