Bio-based polyols and methods for making the same, polyurethane compositions, polyurethane foams, refrigeration equipment

Abstract

This application provides a bio-based polyol and its preparation method, a polyurethane composition, a polyurethane foam, and a refrigeration device. The preparation method of the bio-based polyol includes the following steps: subjecting vegetable oil to alcoholysis to obtain a mixed fatty acid ester; subjecting the mixed fatty acid ester to epoxidation to obtain an epoxy fatty acid ester; subjecting the epoxy fatty acid ester to a ring-opening reaction to obtain a hydroxy fatty acid ester; and in-situ composited with silane-modified nano-aerogel to obtain the bio-based polyol. This application, by introducing silane-modified nano-aerogel into the bio-based polyol for in-situ composite formation, can utilize the low thermal conductivity and high specific surface area of ​​the silane-modified nano-aerogel to synergistically reduce the thermal conductivity of the polyurethane foam.

Description

Technical Field

[0001] This application belongs to the field of polyurethane technology, and particularly relates to a bio-based polyol and its preparation method, polyurethane composition, polyurethane foam, and refrigeration equipment. Background Technology

[0002] Currently, polyurethane foam is commonly used for the insulation layer of refrigeration equipment such as refrigerators and freezers. With the implementation of new energy efficiency standards, refrigeration equipment is moving towards energy conservation, requiring further reductions in power consumption. This hinges on further reducing the thermal conductivity of the polyurethane foam used in the insulation layer. However, existing polyurethane foam has a relatively high thermal conductivity, which is detrimental to reducing the power consumption of refrigeration equipment. Summary of the Invention

[0003] This application provides a bio-based polyol and its preparation method, a polyurethane composition, a polyurethane foam, and a refrigeration device to solve the problem of high thermal conductivity in existing polyurethane foams.

[0004] In a first aspect, embodiments of this application provide a method for preparing a bio-based polyol, the method comprising the following steps:

[0005] S100. The vegetable oil is subjected to alcoholysis to obtain a mixture of fatty acid esters; S200. The mixed fatty acid ester is subjected to an epoxidation reaction to obtain an epoxy fatty acid ester. S300, The epoxy fatty acid ester is subjected to a ring-opening reaction to obtain a hydroxy fatty acid ester; S400. The hydroxy fatty acid ester is in situ compounded with silane-modified nano-aerogel to obtain a bio-based polyol.

[0006] Optionally, the ring-opening reaction of the epoxy fatty acid ester includes: adding a composite ring-opening agent containing diisopropanolamine and triethanolamine to the epoxy fatty acid ester, reacting at 80℃~150℃ for 4h~10h to obtain a hydroxy fatty acid ester; and / or, the mass ratio of the diisopropanolamine, the triethanolamine and the vegetable oil is (20~30):(3~8):100.

[0007] Optionally, the silane-modified nano-aerogel is a silane-modified nano-silicon-based aerogel, which is selected from one or more of silane-modified nano-silica aerogel, silane-modified nano-alumina silica aerogel, and silane-modified nano-zirconium silica aerogel; and / or, the particle size of the silane-modified nano-aerogel is 50 nm to 200 nm, and the mass ratio of the silane-modified nano-aerogel to the vegetable oil is (1 to 5): 100.

[0008] Optionally, step S400 includes: S410, adding a functional monomer containing an ether bond and an initiator to the hydroxy fatty acid ester to perform a grafting reaction, so that the functional monomer is grafted onto the hydroxy fatty acid ester to obtain a first system, wherein the grafting reaction temperature is 70℃~90℃ and the time is 2h~4h; S420, adding silane-modified nano-aerogel to the first system, so that the silane-modified nano-aerogel is in situ composited with the hydroxy fatty acid ester to obtain a second system; S430, heating the second system to 90℃~110℃, and then adding an in situ release accelerator, so that the in situ release accelerator is in situ composited with the hydroxy fatty acid ester to obtain a bio-based polyol.

[0009] Optionally, the mass ratio of the functional monomer, the initiator, and the vegetable oil is (5~15):(0.3~0.8):100; and / or, the functional monomer includes one or more of polyethylene glycol monomethyl ether acrylate, polyethylene glycol acrylate, polypropylene glycol monomethyl ether acrylate, hydroxyethyl acrylate, and polyethylene glycol methacrylate; and / or, the initiator includes one or more of benzoyl peroxide, azobisisobutyronitrile, tert-butyl peroxide, dicumyl peroxide, methyl ethyl ketone peroxide, and ammonium persulfate; and / or, the mass ratio of the in-situ release accelerator to the vegetable oil is (2~6):100; and / or, the in-situ release accelerator is selected from one or more of polysiloxane-grafted polyether, polyether-modified silicone oil, organosiloxane-polyether block copolymer, fluorinated polyether, and polyoxyethylene-polyoxypropylene block copolymer.

[0010] Optionally, step S100 includes: mixing vegetable oil, alcoholysis agent and alcoholysis catalyst at a mass ratio of 100:(35~55):(0.5~1.2), and reacting at 80℃~120℃ for 2h~6h to obtain mixed fatty acid esters.

[0011] Optionally, the alcoholysis agent comprises an alcohol and an alkanolamine, wherein the mass ratio of the alcohol to the alkanolamine is (30~45):(5~10); the alcohol is selected from one or more of glycerol, 1,2-propanediol, ethylene glycol, and pentaerythritol; the alkanolamine is selected from one or more of diethanolamine, triethanolamine, monoethanolamine, and diisopropanolamine; and / or, the alcoholysis catalyst is an alkaline catalyst, wherein the alkaline catalyst is selected from one or more of potassium hydroxide, sodium hydroxide, and lithium hydroxide; and / or, the vegetable oil is selected from one or more of jatropha oil and rapeseed oil.

[0012] Optionally, step S200 includes: mixing a mixed fatty acid ester, an epoxidizing agent, and an epoxidation catalyst, and reacting them at 40°C to 60°C for 3 to 8 hours to obtain an epoxidized fatty acid ester.

[0013] Optionally, the epoxidizing agent comprises short-chain fatty acids and peroxides, wherein the mass ratio of the short-chain fatty acids, the peroxides, and the vegetable oil is (8-12):(25-35):100; the short-chain fatty acids are selected from one or more of formic acid, acetic acid, and propionic acid, and the peroxides are selected from one or more of hydrogen peroxide, peracetic acid, and m-chloroperoxybenzoic acid; and / or, the epoxidation catalyst comprises a solid acid and a Lewis acid, wherein the mass ratio of the solid acid, the Lewis acid, and the vegetable oil is (1.5-3):(0.3-0.8):100; the solid acid is selected from sulfonic acid ion exchange resins, zirconium sulfate, phosphotungstic acid, modified montmorillonite, zeolite molecular sieves, and SO4²⁻. - One or more of / TiO2, wherein the Lewis acid is selected from one or more of tetrabutyl titanate, tetraisopropyl titanate, tetraethyl titanate, aluminum isopropoxide, and titanium acetylacetonate.

[0014] Secondly, embodiments of this application also provide a bio-based polyol, which is prepared by the above-described method for preparing bio-based polyols.

[0015] Optionally, the hydroxyl value of the bio-based polyol is 320 mg KOH / g to 360 mg KOH / g; and / or, the melt flow rate of the bio-based polyol is ≥38 g / 10 min.

[0016] Thirdly, embodiments of this application also provide a polyurethane composition comprising isocyanate, foaming agent and the above-mentioned bio-based polyol.

[0017] Optionally, the mass ratio of the bio-based polyol, the isocyanate, and the foaming agent is 100:(120~150):(10~15).

[0018] Optionally, the polyurethane composition further includes a foam stabilizer, wherein the mass ratio of the bio-based polyol, the isocyanate, the blowing agent and the foam stabilizer is 100:(120~150):(10~15):(1~3).

[0019] Fourthly, embodiments of this application also provide a polyurethane foam, which is obtained by foaming the above-mentioned polyurethane composition.

[0020] Optionally, the thermal conductivity of the polyurethane foam is ≤17.5mW / (m•K); and / or, the density of the polyurethane foam is ≤28kg / m3 and the compressive strength is ≥145kPa; and / or, the bio-based content of the polyurethane foam is ≥72%.

[0021] Fifthly, embodiments of this application also provide a refrigeration device, the refrigeration device including a heat insulation layer, the heat insulation layer including the above-mentioned polyurethane foam.

[0022] The bio-based polyols and their preparation methods, polyurethane compositions, polyurethane foams, and refrigeration equipment provided in this application embodiment, by introducing silane-modified nano-aerogels into the bio-based polyols for in-situ composite, utilize the low thermal conductivity and high specific surface area of ​​the silane-modified nano-aerogels, and synergize the uniformity of crosslinking density during the reaction of the bio-based polyols with isocyanates, thereby effectively reducing the thermal conductivity of the polyurethane foam. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are merely some embodiments of this application. Those skilled in the art can obtain other drawings based on these drawings without creative effort. In the following description, the same reference numerals denote the same parts.

[0024] Figure 1 A flowchart illustrating the preparation method of bio-based polyols provided in this application embodiment. Detailed Implementation

[0025] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0026] In the description of this application, unless otherwise stated, directional terms such as "upper" and "lower" specifically refer to the drawing directions in the accompanying drawings. Additionally, in the description of this application, the term "comprising" means "including but not limited to". The term "exemplary" is used to mean "serving as an example, illustration, or description," and any embodiment described as "exemplary" is not necessarily to be construed as being more preferred or advantageous than other embodiments. The term "and / or" includes any and all combinations of one or more of the associated listed items. The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features; thus, features defined with "first" or "second" may explicitly or implicitly include one or more of the stated features.

[0027] Various embodiments of this application may exist in the form of a range; it should be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as a hard limitation on the scope of the invention; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values ​​within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers within the range, such as 1, 2, 3, 4, 5, and 6, which applies regardless of the range.

[0028] This application provides a method for preparing bio-based polyols, such as... Figure 1 As shown, the preparation method of the bio-based polyol includes the following steps: S100. The vegetable oil is subjected to alcoholysis to obtain a mixture of fatty acid esters; S200. The mixed fatty acid ester is subjected to an epoxidation reaction to obtain an epoxy fatty acid ester. S300, The epoxy fatty acid ester is subjected to a ring-opening reaction to obtain a hydroxy fatty acid ester; S400. The hydroxy fatty acid ester is in situ compounded with silane-modified nano-aerogel to obtain a bio-based polyol.

[0029] The method for preparing bio-based polyols provided in this application introduces silane-modified nano-aerogels into bio-based polyols for in-situ composite. By utilizing the low thermal conductivity and high specific surface area of ​​the silane-modified nano-aerogels, and synergistically improving the uniformity of crosslinking density during the reaction of bio-based polyols with isocyanates, the thermal conductivity of polyurethane foam can be effectively reduced, thereby improving its thermal insulation performance.

[0030] In some embodiments of this application, step S100 includes: mixing vegetable oil, alcoholysis agent, and alcoholysis catalyst at a mass ratio of 100:(35~55):(0.5~1.2), and reacting them at 80℃~120℃ (e.g., 80℃, 90℃, 100℃, 110℃, or 120℃, etc.) for 2h~6h (e.g., 2h, 3h, 4h, 5h, or 6h, etc.) to obtain a mixed fatty acid ester. By using the above process conditions to alcoholyze the vegetable oil, it is beneficial to reduce the acid value of the mixed fatty acid ester (≤5mgKOH / g), thereby laying the foundation for subsequent processes and meeting the requirements of subsequent epoxidation reaction and precise control of hydroxyl value, so as to reduce the thermal conductivity of polyurethane foam.

[0031] For example, the mass ratio of the vegetable oil, the alcoholysis agent, and the alcoholysis catalyst can be 100:35:0.5, 100:35:0.8, 100:35:1.2, 100:45:0.5, 100:45:0.8, 100:45:1.2, 100:55:0.5, 100:55:0.8, 100:55:1.2, or any range between the two aforementioned ratios.

[0032] Optionally, the alcoholysis agent comprises an alcohol and an alkanolamine, wherein the mass ratio of the alcohol to the alkanolamine is (30-45):(5-10); the alcohol is selected from one or more of glycerol, 1,2-propanediol, ethylene glycol, and pentaerythritol, and the alkanolamine is selected from one or more of diethanolamine, triethanolamine, monoethanolamine, and diisopropanolamine. Exemplarily, the mass ratio of the alcohol to the alkanolamine can be 30:5, 30:8, 30:10, 38:5, 38:8, 38:10, 45:5, 45:8, 45:10, or a range between any two of the aforementioned ratios.

[0033] This application employs an alcoholysis agent containing alkanolamines and alcohols, which not only synergistically improves alcoholysis efficiency and shortens alcoholysis time with the alcoholysis catalyst, but also helps to reduce the acid value of mixed fatty acid esters (≤5mgKOH / g), thus laying the foundation for subsequent processes and meeting the requirements of subsequent epoxidation reaction and precise control of hydroxyl value, so as to reduce the thermal conductivity of polyurethane foam.

[0034] Optionally, the alcoholysis catalyst is an alkaline catalyst, selected from one or more of potassium hydroxide (KOH), sodium hydroxide (NaOH), and lithium hydroxide (LiOH). This application replaces traditional organotin catalysts with alkaline catalysts such as potassium hydroxide in the alcoholysis step, which is environmentally friendly and non-toxic. This solves the environmental hazards associated with using organotin catalysts as alcoholysis catalysts in existing technologies, while also shortening the alcoholysis time and reducing production energy consumption, thus achieving a balance between environmental protection and alcoholysis efficiency.

[0035] Optionally, the vegetable oil is selected from one or more of jatropha oil and rapeseed oil. Traditional polyurethane foams mostly rely on petrochemical polyols, which suffer from the problems of non-renewable raw materials and large cost fluctuations; while existing bio-based polyols mostly use edible oils as raw materials, posing a risk of "competing with consumers for food". This application uses non-grain vegetable oils such as jatropha oil and rapeseed oil as raw materials to prepare bio-based polyols, thus avoiding the risk of "competing with consumers for food", and the raw materials are renewable with small cost fluctuations.

[0036] In some embodiments of this application, step S200 includes: mixing a mixed fatty acid ester, an epoxidizing agent, and an epoxidation catalyst, and reacting them at 40°C to 60°C (e.g., 40°C, 45°C, 50°C, 55°C, or 60°C) for 3 to 8 hours (e.g., 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, or 8 hours) to obtain an epoxy fatty acid ester. By employing the above process conditions for the epoxidation reaction, this application can improve the epoxy value of the epoxy fatty acid ester, thereby laying the foundation for subsequent processes and meeting the requirement for precise control of the hydroxyl value, thus achieving a reduction in the thermal conductivity of polyurethane foam.

[0037] Optionally, the epoxidizing agent comprises short-chain fatty acids and peroxides, wherein the mass ratio of the short-chain fatty acids, the peroxides, and the vegetable oil is (8~12):(25~35):100; the short-chain fatty acids are selected from one or more of formic acid, acetic acid, and propionic acid, and the peroxides are selected from one or more of hydrogen peroxide (H2O2), peracetic acid, and m-chloroperoxybenzoic acid (m-CPBA). This application, by employing an epoxidizing agent containing short-chain fatty acids and peroxides, facilitates the improvement of the epoxy value of epoxy fatty acid esters, thereby laying the foundation for subsequent processes and meeting the need for precise control of the hydroxyl value, thus achieving a reduction in the thermal conductivity of polyurethane foam.

[0038] For example, the mass ratio of the short-chain fatty acid, the peroxide, and the vegetable oil can be 8:25:100, 8:30:100, 8:35:100, 10:25:100, 10:30:100, 10:35:100, 12:25:100, 12:30:100, 12:35:100, or any range between the two aforementioned ratios.

[0039] Optionally, the epoxidation catalyst comprises a solid acid and a Lewis acid, wherein the mass ratio of the solid acid, the Lewis acid, and the vegetable oil is (1.5~3):(0.3~0.8):100. The solid acid is selected from sulfonic acid-type ion exchange resins, zirconium sulfate, phosphotungstic acid, modified montmorillonite, zeolite molecular sieves, and SO4²⁻. - One or more of / TiO2 (sulfate-modified titanium dioxide); the Lewis acid is selected from one or more of tetrabutyl titanate, tetraisopropyl titanate, tetraethyl titanate, aluminum isopropoxide, and titanium acetylacetonate. This application utilizes an epoxidation catalyst containing both a solid acid and a Lewis acid, which facilitates improved reactivity and thus increases the epoxy value of the epoxy fatty acid ester.

[0040] For example, the mass ratio of the solid acid, the Lewis acid, and the vegetable oil can be 1.5:0.3:100, 1.5:0.5:100, 1.5:0.8:100, 2.2:0.3:100, 2.2:0.5:100, 2.2:0.8:100, 3:0.3:100, 3:0.5:100, 3:0.8:100, or any range between the two aforementioned ratios.

[0041] In some embodiments of this application, the ring-opening reaction of the epoxy fatty acid ester (i.e., step S300) includes: adding a composite ring-opening agent containing diisopropanolamine and triethanolamine to the epoxy fatty acid ester, and reacting at 80°C to 150°C (e.g., 80°C, 90°C, 100°C, 110°C, 120°C, 130°C, 140°C, or 150°C, etc.) for 4h to 10h (e.g., 4h, 5h, 6h, 7h, 8h, 9h, or 10h, etc.) to obtain a hydroxy fatty acid ester.

[0042] Understandably, the wide hydroxyl value distribution range of existing bio-based polyols (hydroxyl value range ≥ 130 mg KOH / g) leads to uneven crosslinking density during the reaction of bio-based polyols with isocyanates, resulting in a higher thermal conductivity of the resulting polyurethane foam. This application addresses this issue by using a composite ring-opening agent containing diisopropanolamine and triethanolamine for the ring-opening reaction. Because diisopropanolamine and triethanolamine have complementary reactivity, they can synergistically control the ring-opening rate of epoxy groups, avoiding uneven local reactions. Furthermore, the synergistic spatial structure of diisopropanolamine and triethanolamine limits the fluctuation of hydroxyl value distribution, resulting in a narrower hydroxyl value distribution of the bio-based polyol (hydroxyl value range ≤ 40 mg KOH / g). This ensures a uniform crosslinking density during the reaction of the bio-based polyol with isocyanates, thereby reducing internal pore defects in the polyurethane foam. Simultaneously, the introduction of silane-modified nano-aerogel in situ further reduces the thermal conductivity of the polyurethane foam. Since silane-modified nano-aerogel is a nanoporous material with low thermal conductivity and high specific surface area, it can synergistically reduce the thermal conductivity of the polyurethane foam.

[0043] Optionally, the mass ratio of diisopropanolamine, triethanolamine, and vegetable oil is (20~30):(3~8):100. Under manufacturing cost pressures, it is necessary to maintain compressive strength (≥135kPa) while reducing the core density of polyurethane foam (≤30kg / m³). However, existing polyurethane foams prepared with bio-based polyols often have compressive strengths below 135kPa when the density is ≤30kg / m³, failing to meet the cost-performance requirements of low density and high strength. This application, by controlling the mass ratio of diisopropanolamine to triethanolamine within the above range, can regulate the crosslinking density and strength of polyurethane foam, achieving a balance between low density and high strength, resulting in polyurethane foam with a core density ≤28kg / m³. 3At that time, the compressive strength is ≥145kPa, thus achieving high strength of polyurethane foam while reducing manufacturing costs.

[0044] For example, the mass ratio of the diisopropanolamine, the triethanolamine and the vegetable oil can be 20:3:100, 25:3:100, 30:3:100, 20:5:100, 25:5:100, 30:5:100, 30:8:100 or any range between the two aforementioned values.

[0045] In some embodiments of this application, the silane-modified nano-aerogel is a silane-modified nano-silicon-based aerogel, which is selected from one or more of silane-modified nano-silica aerogel, silane-modified nano-alumina silica aerogel, and silane-modified nano-zirconium silica aerogel.

[0046] Optionally, the silane-modified nano-silica aerogel can be prepared by the following method: after hydrolyzing a silicon source (e.g., tetraethyl orthosilicate) to form a sol, a silane coupling agent (e.g., KH550, KH560, KH570, etc.) is added to introduce active groups for modification, wherein the molar ratio of silicon source to hydrolyzing agent (e.g., water) is 1:(2~5), and the amount of silane coupling agent is 1%~5% of the mass of silicon source; after gelation and aging, the solvent is removed by supercritical drying; finally, it is pulverized and sieved to obtain a silane-modified nano-silica aerogel with a target particle size (e.g., 50nm~200nm).

[0047] Optionally, the particle size of the silane-modified nano-aerogel is 50 nm to 200 nm, and the mass ratio of the silane-modified nano-aerogel to the vegetable oil is (1 to 5): 100. This configuration allows the silane-modified nano-aerogel to be more effectively composited in situ, thereby helping to reduce the thermal conductivity of the polyurethane foam.

[0048] For example, the particle size of the silane-modified nano-aerogel can be 50nm, 80nm, 100nm, 120nm, 150nm, 180nm, 200nm, or any range between two of the aforementioned values; the mass ratio of the silane-modified nano-aerogel to the vegetable oil can be 1:100, 1.5:100, 2:100, 2.5:100, 3:100, 3.5:100, 4:100, 4.5:100, 5:100, or any range between two of the aforementioned ratios.

[0049] In some embodiments of this application, step S400 includes: S410. Add a functional monomer containing an ether bond and an initiator to the hydroxy fatty acid ester to carry out a grafting reaction, so that the functional monomer is grafted onto the hydroxy fatty acid ester to obtain a first system. The grafting reaction temperature is 70℃~90℃ (e.g., 70℃, 75℃, 80℃, 85℃ or 90℃, etc.), and the time is 2h~4h (e.g., 2h, 2.5h, 3h, 3.5h or 4h, etc.). S420. Add silane-modified nano-aerogel to the first system and ultrasonically disperse for 30 min to 60 min (e.g., 30 min, 35 min, 40 min, 45 min, 50 min, 55 min, or 60 min, etc.) to allow the silane-modified nano-aerogel to be in situ composited with the hydroxy fatty acid ester, thereby obtaining the second system. Ultrasonic dispersion can make the silane-modified nano-aerogel uniformly dispersed and form a stable in situ composite system with the polyol matrix. S430. The second system is heated to 90℃~110℃ (e.g., 90℃, 95℃, 100℃, 105℃ or 110℃, etc.), and then an in-situ demolding accelerator is added. The reaction is carried out for 1h~2h (e.g., 1h, 1.2h, 1.5h, 1.8h or 2h, etc.) to allow the in-situ demolding accelerator to recombine with the hydroxy fatty acid ester in situ, thereby obtaining a bio-based polyol.

[0050] In-situ composite refers to the in-situ bonding of functional components with matrix molecules. In step S420, after the silane-modified nano-aerogel is in-situ composited with the hydroxy fatty acid ester, a composite dispersion structure is formed in which the silane-modified nano-aerogel is uniformly dispersed in the polyol matrix. The nanoparticles are in-situ bonded to the polyol molecular chains without significant agglomeration. In step S430, the in-situ release accelerator is in-situ composited with the hydroxy fatty acid ester, forming a molecular-level composite structure in which the in-situ release accelerator and the polyol molecular chains are chemically bonded. This makes the in-situ release accelerator less prone to migration, thus balancing release properties and box adhesion.

[0051] With societal development, ultra-thin refrigerators (wall thickness ≤ 3cm) have become the market mainstream. This requires polyurethane foam raw materials to possess high flow properties to achieve complete filling of complex ultra-thin cavities. However, existing bio-based polyols have high viscosity (melt flow rate ≤ 30g / 10min) and insufficient flow properties, making them unsuitable for filling ultra-thin cavities. This often results in material shortages and air bubble defects during ultra-thin cavity filling. This application utilizes functional monomers containing ether bonds for grafting reactions, thereby introducing flexible ether bonds into the molecular chain of bio-based polyols. This reduces the viscosity of the bio-based polyols, enabling a melt flow rate ≥ 38g / 10min, making them suitable for ultra-thin cavity filling and avoiding material shortages and air bubble defects during ultra-thin cavity filling, thus solving the problem of ultra-thin cavity filling.

[0052] To improve production line efficiency, existing technologies typically add external release agents during polyurethane foam preparation to shorten demolding time. However, adding external release agents can easily lead to a decrease in the adhesion between the polyurethane foam and the refrigeration equipment casing, and the improvement in demolding efficiency is limited. This application utilizes an in-situ release accelerator combined with a hydroxyl fatty acid ester in situ, making the in-situ release accelerator less prone to migration. This avoids the decrease in adhesion caused by the migration of the in-situ release accelerator, ensuring the adhesion between the polyurethane foam and the refrigeration equipment casing. Simultaneously, it enables rapid demolding of the polyurethane foam (demolding time ≤ 2.5 min), thereby improving production efficiency.

[0053] In some embodiments of this application, the mass ratio of the functional monomer, the initiator, and the vegetable oil is (5~15):(0.3~0.8):100. This setting allows for controlling the grafting rate to ≥85%, thereby reducing the viscosity of the bio-based polyol and increasing its melt flow rate. Exemplarily, the mass ratio of the functional monomer, the initiator, and the vegetable oil can be 5:0.3:100, 5:0.5:100, 5:0.8:100, 10:0.3:100, 10:0.5:100, 10:0.8:100, 15:0.3:100, 15:0.5:100, 15:0.8:100, or a range between any two of the aforementioned ratios.

[0054] Optionally, the functional monomer includes one or more of polyethylene glycol monomethyl ether acrylate, polyethylene glycol acrylate, polypropylene glycol monomethyl ether acrylate (PPGMA), hydroxyethyl acrylate (HEA), and polyethylene glycol methacrylate. Optionally, the molecular weight of polyethylene glycol monomethyl ether acrylate, polyethylene glycol acrylate, polypropylene glycol monomethyl ether acrylate, hydroxyethyl acrylate, and polyethylene glycol methacrylate can all be 400-600.

[0055] Optionally, the initiator includes one or more of benzoyl peroxide, azobisisobutyronitrile (AIBN), tert-butyl peroxide, dicumyl peroxide, methyl ethyl ketone peroxide, and ammonium persulfate.

[0056] In some embodiments of this application, the mass ratio of the in-situ release accelerator to the vegetable oil is (2~6):100. Exemplarily, the mass ratio of the in-situ release accelerator to the vegetable oil can be 2:100, 3:100, 4:100, 5:100, 6:100, or any range between the two aforementioned ratios.

[0057] Optionally, the in-situ release accelerator is selected from one or more of polysiloxane-grafted polyether, polyether-modified silicone oil, organosiloxane-polyether block copolymer, fluorinated polyether, and polyoxyethylene-polyoxypropylene block copolymer. Optionally, the molecular weight of the polysiloxane-grafted polyether, the polyether-modified silicone oil, the organosiloxane-polyether block copolymer, the fluorinated polyether, and the polyoxyethylene-polyoxypropylene block copolymer can all be 1000-2000.

[0058] The polysiloxane-grafted polyether can be prepared by the following method: using polysiloxane containing active groups (e.g., vinyl, epoxy groups) and hydroxyl-containing polyether as raw materials, an initiator (e.g., azo initiator, peroxide initiator) or a catalyst (e.g., tin catalyst, alkaline catalyst) is added, and the grafting reaction is carried out at 80℃~120℃ for 3h~8h. After the reaction, impurities are removed by purification (filtration, vacuum distillation) to obtain the polysiloxane-grafted polyether. The mass ratio of the polysiloxane containing active groups to the hydroxyl-containing polyether is 1:(3~8), the amount of initiator is 0.1%~0.5% of the total mass of the initiator, polysiloxane, and polyether, and the amount of catalyst is 0.05%~0.3% of the total mass of the catalyst, polysiloxane, and polyether.

[0059] This application also provides a bio-based polyol, which is prepared by the above-described method for preparing bio-based polyols. Since the bio-based polyol employs all the technical solutions of all the above embodiments, it possesses at least all the beneficial effects brought about by the technical solutions of the above embodiments, and will not be elaborated further here.

[0060] Optionally, the hydroxyl value of the bio-based polyol is 320 mg KOH / g to 360 mg KOH / g. By controlling the hydroxyl value of the bio-based polyol within the range of 320 mg KOH / g to 360 mg KOH / g, the reactivity of the isocyanate can be better matched, resulting in a suitable crosslinking density and balancing the compressive strength (≥100 kPa) and thermal insulation performance of the polyurethane foam. For example, the hydroxyl value of the bio-based polyol can be 320 mg KOH / g, 330 mg KOH / g, 340 mg KOH / g, 350 mg KOH / g, 360 mg KOH / g, or any range between two of the aforementioned values. Optionally, the melt flow rate of the bio-based polyol is ≥38 g / 10 min.

[0061] This application also provides a polyurethane composition comprising isocyanate, a blowing agent, and a bio-based polyol, the specific structure of which is described in the above embodiments. Since this polyurethane composition employs all the technical solutions of the above embodiments, it possesses at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be elaborated upon here.

[0062] In some embodiments of this application, the mass ratio of the bio-based polyol, the isocyanate, and the foaming agent is 100:(120~150):(10~15). By controlling the proportions of each component in the polyurethane composition within the above range, this application enables the polyurethane foam prepared using the polyurethane composition of this application to have a low thermal conductivity and high compressive strength, while also possessing good thermal insulation and mechanical properties.

[0063] For example, the mass ratio of the bio-based polyol, the isocyanate, and the foaming agent can be 100:120:10, 100:120:12, 100:120:15, 100:135:10, 100:135:12, 100:135:15, 100:150:10, 100:150:12, 100:150:15, or any range between the two aforementioned ratios.

[0064] Optionally, the polyurethane composition further includes a foam stabilizer, wherein the mass ratio of the bio-based polyol, the isocyanate, the blowing agent, and the foam stabilizer is 100:(120~150):(10~15):(1~3). This application, by employing a foam stabilizer, can improve the cell stability during polyurethane foam preparation, which is beneficial for the formation of a cross-linked skeleton.

[0065] For example, the mass ratio of the bio-based polyol, the isocyanate, the foaming agent, and the foam stabilizer can be 100:120:10:1, 100:120:12:1, 100:120:15:1, 100:120:10:2, 100:120:12:2, 100:120:15:2, 100:120:10:3, 100:120:12:3, 100:120:15:3, 100:135:10:1, 100:135:12:1, 100:135:1 ... 5∶10∶2, 100∶135∶12∶2, 100∶135∶15∶2, 100∶135∶10∶3, 100∶135∶12∶3, 100∶135∶15∶3, 100∶150∶10∶1, 100∶150∶12∶1, 100∶150∶15∶1, 100∶150∶10∶2, 100∶150∶12∶2, 100∶150∶15∶2, 100∶150∶10∶3, 100∶150∶12∶3, 100∶150∶15∶3, or any range between any two of the aforementioned ratios.

[0066] This application also provides a polyurethane foam, which is obtained by foaming the above-described polyurethane composition. Since this polyurethane foam adopts all the technical solutions of all the above embodiments, it possesses at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be elaborated upon here.

[0067] In some embodiments of this application, the thermal conductivity of the polyurethane foam is ≤17.5 mW / (m•K). Optionally, the density of the polyurethane foam is ≤28 kg / m³. 3 The compressive strength is ≥145 kPa. Optionally, the bio-based content of the polyurethane foam is ≥72%.

[0068] This application also provides a refrigeration device, which includes an insulation layer comprising the aforementioned polyurethane foam. Since this refrigeration device employs all the technical solutions of the above embodiments, it possesses at least all the beneficial effects brought about by the technical solutions of the above embodiments, and will not be elaborated upon further here.

[0069] Optionally, the refrigeration equipment can be a refrigerator, freezer, biological sample transport box, or cold chain container, etc. Taking a refrigerator as an example, the insulation layer can be applied to the side walls of the refrigerator body, the inner lining of the drawers, the partition layer, and the foam layer of the door.

[0070] The technical solutions and effects of this application will be described in detail below through specific embodiments and comparative examples. The following embodiments are only some embodiments of this application and are not intended to limit this application.

[0071] Raw material preparation: (1) Vegetable oils: jatropha oil and rapeseed oil; (2) Alcohololysis agents: glycerol and diethanolamine; (3) Alcohololysis catalyst: potassium hydroxide; (4) Epoxidizing agents: formic acid (90% concentration) and H2O2 (30% concentration); (5) Epoxidation catalyst: sulfonic acid type ion exchange resin and tetrabutyl titanate; (6) Ring-opening agents: diisopropanolamine and triethanolamine; (7) Functional monomer: polyethylene glycol monomethyl ether acrylate (PEGMA), with a molecular weight of 500; (8) Initiator: Benzoyl peroxide (BPO); (9) Silane-modified nano-aerogel: Silane-modified nano-silicon-based aerogel (particle size of 150 nm) is prepared by: using tetraethyl orthosilicate as silicon source, hydrolyzing to form a sol, adding silane coupling agent KH550 to introduce active groups for modification; aging after gelation, removing the solvent by supercritical drying; finally crushing and sieving to obtain silane-modified nano-silicon-based aerogel with a particle size of 150 nm.

[0072] (10) In-situ demolding accelerator: polysiloxane grafted polyether (molecular weight of 1500), which is prepared by using epoxy-containing polysiloxane and hydroxyl-containing polyether as raw materials, adding catalyst KOH, and carrying out grafting reaction at 100°C. After the reaction, impurities are removed by purification (filtration and vacuum distillation) to obtain polysiloxane grafted polyether.

[0073] (11) Isocyanate: Polymerized MDI (model PM2010); (12) Foaming agent: HFO-1233zd(E); (13) Foam stabilizer: Model TEGOSTAB B 8406, manufactured by Evonik Industries Group of Germany.

[0074] Example 1 (1) Add jatropha oil, glycerol, diethanolamine and potassium hydroxide to the reaction vessel and carry out alcoholysis reaction at 100℃ for 4h to obtain a mixed fatty acid ester with an acid value ≤5mgKOH / g; (2) Add formic acid and hydrogen peroxide dropwise to the reaction vessel, and simultaneously add sulfonic acid type ion exchange resin and tetrabutyl titanate. Perform epoxidation reaction at 50°C for 5 hours to obtain epoxy fatty acid esters with an epoxy value of 3.8%~4.2%. (3) Add diisopropanolamine and triethanolamine to the reaction vessel and carry out the ring-opening reaction at 120°C for 6 hours to obtain hydroxy fatty acid esters with hydroxyl values ​​of 320mgKOH / g~360mgKOH / g; (4) Add PEGMA and BPO to the reactor and carry out the grafting reaction at 80°C for 3 hours. The grafting rate is ≥85%, and the first system is obtained. (5) The silane-modified nano-silicon aerogel was added to the first system and ultrasonically dispersed at 400W for 45min for in-situ composite to obtain the second system; (6) Heat the second system to 100°C, add an in-situ demolding accelerator, stir and react for 1.5 h to carry out in-situ composite, cool to room temperature and filter to obtain bio-based polyol; (7) Mix bio-based polyol, isocyanate, foaming agent and foam stabilizer in a mass ratio of 100:130:12:2, then inject into the ultra-thin refrigerator cavity (wall thickness ≤3cm), and foam and cure at room temperature to obtain polyurethane foam.

[0075] Example 2 (1) Add jatropha oil, glycerol, diethanolamine and potassium hydroxide to the reaction vessel and carry out alcoholysis reaction at 110℃ for 3h to obtain a mixed fatty acid ester with an acid value ≤5mgKOH / g; (2) Add formic acid and hydrogen peroxide dropwise to the reaction vessel, and simultaneously add sulfonic acid type ion exchange resin and tetrabutyl titanate. Perform epoxidation reaction at 55°C for 4 hours to obtain epoxy fatty acid esters with an epoxy value of 3.8%~4.2%. (3) Add diisopropanolamine and triethanolamine to the reaction vessel and carry out the ring-opening reaction at 130°C for 5 hours to obtain hydroxy fatty acid esters with hydroxyl values ​​of 320mgKOH / g~360mgKOH / g; (4) Add PEGMA and BPO to the reactor and carry out the grafting reaction at 90°C for 2 hours. The grafting rate is ≥85%, and the first system is obtained. (5) Add the silane-modified nano-silicon aerogel to the first system and ultrasonically disperse it at 500W for 30 minutes to perform in-situ composite to obtain the second system; (6) Heat the second system to 110°C, add in-situ demolding accelerator, stir and react for 1 hour to carry out in-situ composite, cool to room temperature and filter to obtain bio-based polyol; (7) Mix bio-based polyol, isocyanate, foaming agent and foam stabilizer at a mass ratio of 100:135:13:2.5, then inject into the ultra-thin refrigerator cavity (box wall thickness ≤3cm), and foam and cure at room temperature to obtain polyurethane foam.

[0076] Example 3 (1) Add jatropha oil, glycerol, diethanolamine and potassium hydroxide to the reaction vessel and carry out alcoholysis reaction at 90°C for 4 hours to obtain a mixed fatty acid ester with an acid value ≤5mgKOH / g; (2) Add formic acid and hydrogen peroxide dropwise to the reaction vessel, and simultaneously add sulfonic acid type ion exchange resin and tetrabutyl titanate. Perform epoxidation reaction at 45°C for 6 hours to obtain epoxy fatty acid esters with an epoxy value of 3.8%~4.2%. (3) Add diisopropanolamine and triethanolamine to the reaction vessel and carry out the ring-opening reaction at 120°C for 6 hours to obtain hydroxy fatty acid esters with hydroxyl values ​​of 320mgKOH / g~360mgKOH / g; (4) Add PEGMA and BPO to the reactor and carry out the grafting reaction at 80°C for 3 hours. The grafting rate is ≥85%, and the first system is obtained. (5) Add the silane-modified nano-silicon aerogel to the first system and ultrasonically disperse it at 300W for 60min for in-situ composite to obtain the second system; (6) Heat the second system to 90°C, add in-situ demolding accelerator, stir for 2 hours to carry out in-situ composite, cool to room temperature and filter to obtain bio-based polyol; (7) Mix bio-based polyol, isocyanate, foaming agent and foam stabilizer in a mass ratio of 100:125:11:1.5, then inject into the ultra-thin refrigerator cavity (box wall thickness ≤3cm), and foam and cure at room temperature to obtain polyurethane foam.

[0077] Example 4 (1) Add jatropha oil, glycerol, diethanolamine and potassium hydroxide to the reaction vessel and carry out alcoholysis reaction at 105℃ for 3.5h to obtain a mixed fatty acid ester with an acid value ≤5mgKOH / g; (2) Add formic acid and hydrogen peroxide dropwise to the reaction vessel, and simultaneously add sulfonic acid type ion exchange resin and tetrabutyl titanate. Perform epoxidation reaction at 52°C for 4.5 h to obtain epoxy fatty acid ester with an epoxy value of 3.8%~4.2%. (3) Add diisopropanolamine and triethanolamine to the reaction vessel and carry out the ring-opening reaction at 125°C for 5.5 h to obtain hydroxy fatty acid esters with hydroxyl values ​​of 320 mg KOH / g to 360 mg KOH / g; (4) Add PEGMA and BPO to the reactor and carry out the grafting reaction at 85°C for 2.5 h to obtain the first system; (5) The silane-modified nano-silicon aerogel was added to the first system and ultrasonically dispersed at 400W for 45min for in-situ composite to obtain the second system; (6) The second system was heated to 105°C, an in-situ demolding accelerator was added, and the mixture was stirred for 1.5 h to carry out in-situ composite. After cooling to room temperature, the mixture was filtered to obtain bio-based polyol. (7) Mix bio-based polyol, isocyanate, foaming agent and foam stabilizer in a mass ratio of 100:140:14:2.2, then inject into the ultra-thin refrigerator cavity (wall thickness ≤3cm), and foam and cure at room temperature to obtain polyurethane foam.

[0078] Example 5 (1) Add jatropha oil, glycerol, diethanolamine and potassium hydroxide to the reaction vessel and carry out alcoholysis reaction at 100℃ for 4h to obtain a mixed fatty acid ester with an acid value ≤5mgKOH / g; (2) Add formic acid and hydrogen peroxide dropwise to the reaction vessel, and simultaneously add sulfonic acid type ion exchange resin and tetrabutyl titanate. Perform epoxidation reaction at 50°C for 5 hours to obtain epoxy fatty acid esters with an epoxy value of 3.8%~4.2%. (3) Add diisopropanolamine and triethanolamine to the reaction vessel and carry out the ring-opening reaction at 120°C for 6 hours to obtain hydroxy fatty acid esters with hydroxyl values ​​of 320mgKOH / g~360mgKOH / g; (4) Add PEGMA and BPO to the reactor and carry out the grafting reaction at 80°C for 3 hours to obtain the first system; (5) The silane-modified nano-silicon aerogel was added to the first system and ultrasonically dispersed at 400W for 45min for in-situ composite to obtain the second system; (6) The second system was heated to 98°C, an in-situ demolding accelerator was added, and the mixture was stirred for 1.5 h to carry out in-situ composite. After cooling to room temperature, the mixture was filtered to obtain bio-based polyol. (7) Mix bio-based polyol, isocyanate, foaming agent and foam stabilizer in a mass ratio of 100:132:12.5:2, then inject into the ultra-thin refrigerator cavity (box wall thickness ≤3cm), and foam and cure at room temperature to obtain polyurethane foam.

[0079] Example 6 (1) Add jatropha oil, glycerol, diethanolamine and potassium hydroxide to the reaction vessel and carry out alcoholysis reaction at 95°C for 4.5 h to obtain a mixed fatty acid ester with an acid value ≤5 mgKOH / g; (2) Add formic acid and hydrogen peroxide dropwise to the reaction vessel, and simultaneously add sulfonic acid type ion exchange resin and tetrabutyl titanate. Perform epoxidation reaction at 48°C for 5.5 h to obtain epoxy fatty acid ester with epoxy value of 3.8%~4.2%. (3) Add diisopropanolamine and triethanolamine to the reaction vessel and carry out the ring-opening reaction at 115°C for 6.5 h to obtain hydroxy fatty acid esters with hydroxyl values ​​of 320 mg KOH / g to 360 mg KOH / g; (4) Add PEGMA and BPO to the reactor and carry out the grafting reaction at 80°C for 3 hours to obtain the first system; (5) The silane-modified nano-silicon aerogel was added to the first system and ultrasonically dispersed at 400W for 45min for in-situ composite to obtain the second system; (6) Heat the second system to 95°C, add in-situ demolding accelerator, stir for 2 hours to carry out in-situ composite, cool to room temperature and filter to obtain bio-based polyol; (7) Mix bio-based polyol, isocyanate, foaming agent and foam stabilizer in a mass ratio of 100:128:11.5:1.8, then inject into the ultra-thin refrigerator cavity (wall thickness ≤3cm), and foam and cure at room temperature to obtain polyurethane foam.

[0080] Comparative Example 1 (1) Jatropha curcas oil, glycerol, diethanolamine and organotin catalyst (dibutyltin dilaurate) were added to the reactor and subjected to alcoholysis reaction at 80°C for 10 h to obtain mixed fatty acid esters; (2) Add formic acid, hydrogen peroxide and tetrabutyl titanate to the reaction vessel and react at 60°C for 8 hours to obtain epoxy fatty acid esters with an epoxy value of 3.3%~3.6%. (3) Add diisopropanolamine as a ring-opening agent to the reaction vessel and react at 100°C for 8 hours to obtain hydroxy fatty acid esters with hydroxyl values ​​of 250 mg KOH / g to 380 mg KOH / g; (4) Add an external release agent (polydimethylsiloxane) to the reaction vessel, stir and mix to obtain a bio-based polyol; (5) Mix bio-based polyol, isocyanate, foaming agent and foam stabilizer in a mass ratio of 100:120:10:1, then inject into the ultra-thin refrigerator cavity (wall thickness ≤3cm), and foam and cure at room temperature to obtain polyurethane foam.

[0081] Comparative Example 2 (1) Mix petrochemical polyol with external release agent (polydimethylsiloxane) for 30 min to obtain petrochemical polyol mixture; (2) Mix the petrochemical polyol mixture, isocyanate, foaming agent and foam stabilizer at a mass ratio of 100:150:15:3, then inject the mixture into the ultra-thin refrigerator cavity (the wall thickness of the box is ≤3cm), and allow it to foam and cure at room temperature to obtain polyurethane foam.

[0082] Comparative Example 3 (1) Jatropha curcas oil, glycerol, diethanolamine and organotin catalyst (dibutyltin dilaurate) were added to the reactor and subjected to alcoholysis reaction at 80°C for 10 h to obtain mixed fatty acid esters; (2) Add formic acid, hydrogen peroxide and tetrabutyl titanate to the reaction vessel and react at 60°C for 8 hours to obtain epoxy fatty acid esters with an epoxy value of 3.3%~3.6%. (3) Add diisopropanolamine as a ring-opening agent to the reaction vessel and react at 100°C for 8 hours to obtain hydroxy fatty acid esters with hydroxyl values ​​of 250 mg KOH / g to 380 mg KOH / g; (4) Add unmodified nano-silica-based aerogel to the reactor and stir mechanically for 60 min; (5) Add an external release agent (polydimethylsiloxane) to the reaction vessel, stir and mix to obtain a bio-based polyol; (6) Mix bio-based polyol, isocyanate, foaming agent and foam stabilizer in a mass ratio of 100:122:10.5:1.2, then inject into the ultra-thin refrigerator cavity (wall thickness ≤3cm), and foam and cure at room temperature to obtain polyurethane foam.

[0083] Specifically, the amount (parts by mass) of each raw material added in Examples 1-6 and Comparative Examples 1-3 is shown in Table 1 below.

[0084] Table 1

[0085] Performance tests were conducted on the bio-based polyol / petrochemical polyol blends and polyurethane foams of Examples 1-6 and Comparative Examples 1-3. The test results are detailed in Table 2 below. The performance test items included: thermal conductivity of polyurethane foam (10℃), demolding time, core density, compressive strength, adhesion to the box, bio-based content, heavy metal content, and melt flow rate of the bio-based polyol / petrochemical polyol blend.

[0086] The test method for thermal conductivity is as follows: according to GB / T 10294-2008, the thermal conductivity of polyurethane foam at 10℃ is determined by the protective hot plate method.

[0087] The test method for melt flow rate is as follows: determine the flow rate of bio-based polyols or petrochemical polyol mixtures in accordance with GB / T 3682.1-2018.

[0088] The demolding time test method is to record the time from polyurethane foam injection to successful demolding.

[0089] The test method for core density is as follows: determine the core density of polyurethane foam according to GB / T 6343-2009.

[0090] The test method for compressive strength is as follows: the compressive strength of polyurethane foam is determined using a universal testing machine in accordance with GB / T 8813-2022.

[0091] The test method for adhesion between the polyurethane foam and the refrigerator body is as follows: according to GB / T 26689-2024, the peel test method is used to determine the adhesion between the polyurethane foam and the refrigerator body.

[0092] The test method for bio-based content is as follows: according to GB / T 29649-2013, the bio-based content of polyurethane foam is determined by carbon-14 isotope analysis.

[0093] Table 2

[0094] As can be seen from Table 2: Examples 1-6 all meet the new requirements of the refrigerator industry: the melt flow rate of bio-based polyols is ≥38g / 10min, and the thermal conductivity of polyurethane foam is ≤17.4mW / (m²). K), demolding time ≤2.4min, core density ≤28kg / m³, compressive strength ≥146kPa, bio-based content ≥72%, and no heavy metal tin was detected, achieving renewable raw materials, environmentally friendly and non-toxic, and can be widely used in the production of refrigerator insulation layers.

[0095] The melt flow rates of the bio-based polyols in Examples 1-6 (38 g / 10 min to 41 g / 10 min) were all greater than those of the bio-based polyol / petrochemical polyol mixtures in Comparative Examples 1-3 (29 g / 10 min to 32 g / 10 min). This indicates that the use of functional monomers containing ether bonds for grafting reactions during the preparation of bio-based polyols in Examples 1-6 is beneficial to improving the flow properties of the bio-based polyols.

[0096] The thermal conductivity of the polyurethane foams in Examples 1-6 is 17.0 W / (m²). K)~17.4W / (m The thermal conductivity (K) of the polyurethane foams in Comparative Examples 1-3 is lower than that of the polyurethane foams in Comparative Examples 1-3 (18.5 W / (m²)). K)~18.8W / (m K)) This illustrates that in the preparation of bio-based polyols in Examples 1-6, the use of a composite ring-opening agent containing diisopropanolamine and triethanolamine for ring-opening reaction, as well as the introduction of silane-modified nano-aerogel in situ composite, helps to reduce the thermal conductivity of polyurethane foam.

[0097] The demolding times of the polyurethane foams in Examples 1-6 (2.1 min-2.4 min) were all shorter than those of the polyurethane foams in Comparative Examples 1-3 (5.2 min-5.8 min). Furthermore, the adhesion between the polyurethane foams in Examples 1-6 and the box (1.7 N / cm²-1.9 N / cm²) was greater than that between the polyurethane foams in Comparative Examples 1-3 and the box (1.2 N / cm²-1.5 N / cm²). This indicates that in the preparation of bio-based polyols, Examples 1-6, by introducing an in-situ demolding accelerator and in-situ compounding, effectively improved the adhesion between the polyurethane foam and the box and shortened the demolding time of the polyurethane foam.

[0098] The core density of the polyurethane foam in Examples 1-6 (26 kg / m³-28 kg / m³) is lower than that of the polyurethane foam in Comparative Examples 1-3 (31 kg / m³-32 kg / m³), and the compressive strength of the polyurethane foam in Examples 1-6 (146 kPa-152 kPa) is higher than that of the polyurethane foam in Comparative Examples 1-3 (132 kPa-140 kPa). This indicates that in the preparation of bio-based polyols, Examples 1-6 can control the crosslinking density and strength of polyurethane foam by controlling the mass ratio of the ring-opening agent diisopropanolamine to triethanolamine within the range of (20-30):(3-8), thus achieving a balance between low density and high strength.

[0099] In summary, this application has, but is not limited to, the following advantages: (1) By using a composite ring-opening agent containing diisopropanolamine and triethanolamine, the hydroxyl value distribution of bio-based polyols is controlled within a narrow range. Combined with in-situ composite of silane-modified nano-aerogels, the thermal conductivity of polyurethane foam is made ≤17.5mW / (m K); (2) By using functional monomers containing ether bonds for grafting reaction, the viscosity of bio-polyols can be reduced, thereby improving the flow properties of bio-based polyols (melt flow rate ≥38g / 10min), and adapting them to complete filling of complex cavities in ultra-thin refrigerators (wall thickness ≤3cm).

[0100] (3) By using in-situ release accelerators (such as polysiloxane-grafted polyether) to bond in situ, the rapid demolding of polyurethane foam (demolding time ≤ 2.5 min) is achieved, improving production efficiency, while ensuring the adhesion between polyurethane foam and the box (adhesion ≥ 1.5 N / cm²).

[0101] (4) By controlling the mass ratio of ring-opening agent diisopropanolamine to triethanolamine within the range of (20~30): (3~8), the crosslinking density and strength of polyurethane foam can be controlled, so as to achieve a compressive strength of ≥145kPa when the core density of polyurethane foam is ≤28kg / m³, thereby reducing manufacturing costs.

[0102] (5) The alcoholysis catalyst uses alkaline catalysts such as potassium hydroxide to replace the traditional organotin catalysts, achieving no heavy metal detection and being environmentally friendly and non-toxic.

[0103] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0104] The above provides a detailed description of the bio-based polyols and their preparation methods, polyurethane compositions, polyurethane foams, and refrigeration equipment provided in the embodiments of this application. Specific examples have been used to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the methods and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A method for the preparation of a bio-based polyol, characterized in that, The method comprises the following steps: S100, subjecting the plant oil to an alcoholysis reaction to obtain a mixed fatty acid ester; S200, subjecting the mixed fatty acid ester to an epoxidation reaction to obtain an epoxy fatty acid ester; S300, subjecting the epoxy fatty acid ester to an opening ring reaction to obtain a hydroxyl fatty acid ester; S400, in-situ compounding the hydroxyl fatty acid ester with silane-modified nano aerogel to obtain a bio-based polyol.

2. The method of producing a bio-based polyol according to claim 1, characterized in that, The opening ring reaction of the epoxy fatty acid ester comprises: adding a composite opening ring agent comprising diisopropanolamine and triethanolamine into the epoxy fatty acid ester, and reacting at 80-150℃ for 4-10h to obtain the hydroxyl fatty acid ester; And / or, the mass ratio of the diisopropanolamine, the triethanolamine and the plant oil is (20-30):(3-8):

100.

3. The method of producing a bio-based polyol according to claim 1, wherein, The silane-modified nano aerogel is a silane-modified nano silicon-based aerogel, and the silane-modified nano silicon-based aerogel is selected from one or more of a silane-modified nano silicon dioxide aerogel, a silane-modified nano silicon aluminum aerogel and a silane-modified nano silicon zirconium aerogel; And / or, the particle size of the silane-modified nano aerogel is 50-200nm, and the mass ratio of the silane-modified nano aerogel and the plant oil is (1-5):

100.

4. The method of making a bio-based polyol according to claim 1, wherein, The step S400 comprises: S410, adding a functional monomer containing an ether bond and an initiator into the hydroxyl fatty acid ester to perform a grafting reaction, so that the functional monomer is grafted onto the hydroxyl fatty acid ester to obtain a first system, wherein the temperature of the grafting reaction is 70-90℃, and the time is 2-4h; S420, adding silane-modified nano aerogel into the first system to in-situ compound the silane-modified nano aerogel with the hydroxyl fatty acid ester to obtain a second system; S430, heating the second system to 90-110℃, and then adding an in-situ demolding promoter to in-situ compound the in-situ demolding promoter with the hydroxyl fatty acid ester to obtain a bio-based polyol.

5. The method of producing a bio-based polyol according to claim 4, characterized in that, The mass ratio of the functional monomer, the initiator and the plant oil is (5-15):(0.3-0.8):100; And / or, the functional monomer comprises one or more of polyethylene glycol monomethyl ether acrylate, polyethylene glycol acrylate, polypropylene glycol monomethyl ether acrylate, hydroxyethyl acrylate and polyethylene glycol methacrylate; And / or, the initiator comprises one or more of dibenzoyl peroxide, azobisisobutyronitrile, tertiary butyl peroxide, dicumyl peroxide, methyl ethyl ketone peroxide and ammonium persulfate; And / or, the mass ratio of the in-situ demolding promoter and the plant oil is (2-6):100; And / or, the in-situ demolding promoter is selected from one or more of polysiloxane grafted polyether, polyether modified silicone oil, organosiloxane-polyether block copolymer, fluorine modified polyether and polyoxyethylene-polyoxypropylene block copolymer.

6. The method of making a bio-based polyol according to claim 1, wherein, The step S100 comprises: Mixing the plant oil, an alcoholysis agent and an alcoholysis catalyst in a mass ratio of 100:(35-55):(0.5-1.2), and reacting at 80-120℃ for 2-6h to obtain the mixed fatty acid ester.

7. The method of producing a bio-based polyol according to claim 6, characterized in that, The alcoholysis agent comprises alcohol and alcohol amine, and a mass ratio of the alcohol to the alcohol amine is (30-45):(5-10); the alcohol is selected from one or more of glycerol, 1,2-propanediol, ethylene glycol and pentaerythritol, and the alcohol amine is selected from one or more of diethanolamine, triethanolamine, monoethanolamine and diisopropyl alcohol amine; And / or, the alcoholysis catalyst is an alkali catalyst, and the alkali catalyst is selected from one or more of potassium hydroxide, sodium hydroxide and lithium hydroxide; And / or, the vegetable oil is selected from one or more of jatropha oil and rapeseed oil.

8. The method of making a bio-based polyol according to claim 1, wherein, The step S200 comprises: Mixing the mixed fatty acid ester, the epoxidation agent and the epoxidation catalyst, and reacting at 40-60°C for 3-8h to obtain an epoxy fatty acid ester.

9. The method of producing a bio-based polyol according to claim 8, characterized in that, The epoxidation agent comprises short-chain fatty acid and peroxide, and a mass ratio of the short-chain fatty acid, the peroxide and the vegetable oil is (8-12):(25-35):100; the short-chain fatty acid is selected from one or more of formic acid, acetic acid and propionic acid, and the peroxide is selected from one or more of hydrogen peroxide, peracetic acid and m-chloroperbenzoic acid; and / or, the epoxidation catalyst comprises a solid acid and a Lewis acid, a mass ratio of the solid acid, the Lewis acid and the vegetable oil is (1.5~3):(0.3~0.8):100; the solid acid is selected from a sulfonic acid type ion exchange resin, zirconium sulfate, phosphotungstic acid, modified montmorillonite, zeolite molecular sieve and SO4 - one or more of TiO2, the Lewis acid is selected from one or more of tetrabutyl titanate, tetraisopropyl titanate, tetraethyl titanate, aluminum isopropyl alcohol and titanium acetylacetone.

10. A bio-based polyol, characterized in that, The bio-based polyol is prepared by the method for preparing a bio-based polyol according to any one of claims 1-9.

11. The bio-based polyol according to claim 10, characterized in that, The bio-based polyol has a hydroxyl value of 320-360mgKOH / g. And / or, the bio-based polyol has a melt flow rate of ≥38g / 10min.

12. A polyurethane composition, characterized in that, The polyurethane composition comprises isocyanate, blowing agent and the bio-based polyol according to any one of claims 10-11.

13. The polyurethane composition according to claim 12, characterized in that, A mass ratio of the bio-based polyol, the isocyanate and the blowing agent is 100:(120-150):(10-15).

14. The polyurethane composition of claim 12, wherein, The polyurethane composition further comprises a foam stabilizer, and a mass ratio of the bio-based polyol, the isocyanate, the blowing agent and the foam stabilizer is 100:(120-150):(10-15):(1-3).

15. A polyurethane foam characterized by, The polyurethane foam is prepared by foaming the polyurethane composition according to any one of claims 12-14.

16. The polyurethane foam according to claim 15, characterized in that, The polyurethane foam has a thermal conductivity of ≤17.5mW / (m·K); And / or, the polyurethane foam has a density of ≤28kg / m3 and a compressive strength of ≥145kPa; And / or, the polyurethane foam has a bio-based content of ≥72%.

17. A refrigeration appliance characterized by, The thermal insulation layer comprises the polyurethane foam according to any one of claims 15-16.

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