Composite foaming material, preparation method thereof and refrigerator

Abstract

The invention discloses a composite foaming material, a preparation method thereof and a refrigerator, and relates to the technical field of foaming materials. The composite foaming material comprises a foaming agent composition, a polyol composition and isocyanate, the foaming agent composition comprises a gradient active unit, a low-temperature stabilizing unit and a flow aiding unit. The gradient active unit comprises glycerol carbonate and hydroxyl-terminated polyether. The low-temperature stabilizing unit comprises an organic-inorganic hybrid material; the flow aiding unit comprises an alkane foaming agent and a fluorine-containing olefin foaming agent; the polyol composition includes a polyether polyol. All the components in the composite foam material cooperate with one another, through multiple mechanisms such as reaction time sequence matching, structural complementation and performance linkage, the triangular contradiction of fluidity-curing property-low-temperature stability in an ultrathin-wall narrow-channel scene is solved, and the excellent comprehensive performance of high filling rate, short demolding time and low shrinkage rate is achieved.

Description

Technical Field

[0001] This application relates to the field of foamed materials technology, and in particular to a composite foamed material and its preparation method, and a refrigerator. Background Technology

[0002] A refrigerator is a refrigeration device that maintains a constant low temperature, and it is also a product that keeps food or other items at a constant low temperature. Foamed material is a closed-cell rigid foam that is chemically foamed and cured in the space between the refrigerator's outer shell and inner liner. The core function of foamed material is to create a continuous and uniform thermal insulation layer, minimizing the transfer of heat from the external environment to the refrigerator's interior, thereby maintaining a low-temperature environment and reducing energy consumption.

[0003] As refrigerators develop towards "ultra-thin, energy-saving, and environmentally friendly" designs, foaming materials and their molding technologies face several challenges: Existing foaming systems have poor flowability and curing speed matching, easily leading to material shortages and shrinkage cavities in structures with narrow wall thicknesses and narrow channel widths, resulting in low fill rates and difficulty meeting the lightweight design requirements of refrigerator bodies; traditional physical foaming agents (such as cyclopentane) can reduce thermal conductivity, but when used alone, they are prone to cell rupture due to rapid evaporation in narrow channels, while chemical foaming agents (such as glyceryl carbonate) have low GWP (Global Warming Potential) values, but high thermal conductivity when used alone, making it difficult to meet the energy consumption requirements of refrigerators; existing foams exhibit large dimensional deformation rates under temperature changes from -30℃ to 70℃, and are prone to cracking due to stress concentration in ultra-thin wall structures, affecting the long-term sealing performance of the refrigerator body.

[0004] Therefore, there is an urgent need to develop a new foaming system that is compatible with the new structure of refrigerators and takes into account both environmental protection and energy saving. Summary of the Invention

[0005] In view of this, this application provides a composite foaming material and its preparation method, as well as a refrigerator.

[0006] The embodiments of this application are implemented as follows: a composite foaming material includes a foaming agent composition, a polyol composition, and an isocyanate; The foaming agent composition includes a gradient active unit, a low-temperature stabilizing unit, and a flow aid unit; the gradient active unit includes glycerol carbonate and hydroxyl-terminated polyether; the low-temperature stabilizing unit includes an organic-inorganic hybrid material; and the flow aid unit includes an alkane foaming agent and a fluorinated olefin foaming agent. The polyol composition includes polyether polyols.

[0007] Optionally, in some embodiments of this application, the organic-inorganic hybrid material includes one or more of silane-modified silica, hydroxyapatite-grafted chitosan, and silane-modified nano-calcium carbonate; Alkane blowing agents include one or more of cyclopentane and isopentane; Fluorinated olefin blowing agents include one or more of 1-chloro-3,3,3-trifluoropropene, 1,1,1,4,4,4-hexafluoro-2-butene, and 3,3,3-trifluoropropene; In the gradient active unit, the mass ratio of glycerol carbonate to hydroxyl-terminated polyether is (1~3):1; In the flow aid unit, the mass ratio of alkane blowing agent to fluorinated olefin blowing agent is (2~5):1.

[0008] Optionally, in some embodiments of this application, the isocyanate content in the isocyanate is 30%~32%, and the insoluble matter content is less than or equal to 0.02%; Isocyanates include one or more of polymethylene polyphenyl isocyanates, non-phosgene toluene diisocyanates, aliphatic isocyanates, and hydrogenated diphenylmethane diisocyanates; The mass ratio of the flow aid unit to isocyanate is 1:(8~12); The mass ratio of the flow aid unit to isocyanate and to the polyol composition is (1.2~1.5):1.

[0009] Optionally, in some embodiments of this application, the polyether polyol includes one or more of sucrose-glycerol polyether and bio-based polyether; wherein, The hydroxyl value of sucrose-glycerol polyether is 350 mg KOH / g to 450 mg KOH / g; The hydroxyl value of bio-based polyethers is 350 mg KOH / g to 450 mg KOH / g; The mass ratio of sucrose-glycerol polyether to bio-based polyether is (3~5):1.

[0010] Optionally, in some embodiments of this application, the polyol composition further includes one or more of a catalyst, a surfactant, and an antioxidant.

[0011] Optionally, in some embodiments of this application, the catalyst includes one or more of amine catalysts and tin catalysts; optionally, the amine catalyst includes one or more of pentamethyldiethylenetriamine, triethylenediamine, N,N-dimethylcyclohexylamine, bis(dimethylaminoethyl) ether, and dimethylethanolamine; the tin catalyst includes dibutyltin dilaurate; optionally, the mass ratio of amine catalyst to tin catalyst is (0.5~2):1; Surfactants include one or more of the following: polyether-modified silicone, silicone-polyamide copolymer, polyetheramine-modified silicone oil, and fatty alcohol polyoxyethylene ether. Antioxidants include hindered phenolic antioxidants; hindered phenolic antioxidants include one or more of antioxidant 1010, antioxidant 702, antioxidant 2246, antioxidant 1076, and antioxidant 5057; The mass ratio of polyether polyol, catalyst, surfactant and antioxidant is (60~80):(2~5):(1~3):(0.5~1.5).

[0012] Optionally, in some embodiments of this application, the mass ratio of the gradient active unit, the low-temperature stabilizing unit, and the flow-aiding unit is (30~50):(5~15):(35~65); The average diameter of the pores formed by the foaming of composite foam materials is 50μm~150μm.

[0013] Accordingly, this application also provides a method for preparing a composite foamed material, comprising the following steps: A flow aid unit and isocyanate are provided, mixed, and a premix is ​​obtained; The premix, polyol composition, gradient active unit, and low-temperature stable unit are mixed to obtain foaming stock solution; The foaming solution is injected into a mold to foam, thus obtaining a composite foamed material. The gradient active unit includes glycerol carbonate and hydroxyl-terminated polyether; the low-temperature stable unit includes organic-inorganic hybrid materials; the flow aid unit includes alkane blowing agents and fluorinated olefin blowing agents; and the polyol composition includes polyether polyols.

[0014] Optionally, in some embodiments of this application, the mixing temperature of the flow aid unit and the isocyanate is 3°C to 10°C, and the mixing time is 10s to 15s; The viscosity of the premix is ​​less than or equal to 80 mPa·s; The premix and polyol composition, gradient active unit and low temperature stable unit are mixed and then stirred; optionally, the stirring speed is 3000 rpm to 4000 rpm and the stirring time is 5s to 8s. The pressure of the foaming liquid injected into the mold is 0.3MPa~0.5MPa, the temperature of the mold is 40℃~45℃, and the holding time after the foaming liquid is injected into the mold is 25s~60s.

[0015] Accordingly, this application also provides a refrigerator, including a cabinet, the interlayer of which is provided with the above-mentioned composite foam material, or includes the composite foam material prepared by the above-mentioned preparation method.

[0016] The composite foaming material provided in this application includes a foaming agent composition comprising a gradient active unit, a low-temperature stabilizing unit, and a flow-aiding unit. The glycerol carbonate in the gradient active unit and the hydroxyl groups in the hydroxyl-terminated polyether can gradually react with isocyanate to generate polyurethane, thereby achieving the effect of "low activity in the early stage to maintain flow, and high activity in the later stage to promote curing." Furthermore, glycerol carbonate has an extremely low GWP (GWP < 1), making it environmentally friendly. The molecular structure of glycerol carbonate can form weak interactions with the polyurethane molecular chains, inserting itself between polymer chains, weakening the inter-chain interaction forces, and increasing the mobility of chain segments, thus making the foam softer and reducing its brittleness. The properties of the foam allow it to better recover its original shape after being compressed, and also prevent the foam from hardening and becoming brittle at low temperatures. Furthermore, the hydroxyl groups at the ends of the glycerol carbonate molecules impart reactivity, which can effectively reduce the viscosity of the system to a certain extent before foaming. This makes the mixing of the components more uniform, improves the flowability, facilitates filling, and reduces defects such as material shortages caused by poor flowability. The organic-inorganic hybrid material in the low-temperature stabilization unit can inhibit the shrinkage of the cells at low temperatures through chemical action. The alkane foaming agent in the flow aid unit provides a low thermal conductivity, and the fluorinated olefin foaming agent has good environmental performance. The combined viscosity of the two is low, which can improve the flowability of the system. The components of the foaming agent composition work synergistically to meet the filling and rapid demolding requirements of ultra-thin walls and narrow channels, improve the filling rate, and alleviate phenomena such as material shortage and shrinkage during foaming. The polyether polyol in the polyol composition, as one of the raw materials of polyurethane foam, has the characteristics of high functionality, fine cell structure and good dimensional stability, which can effectively improve the foam performance. The foaming agent composition and polyol composition in this application are compounded and mixed to promote curing while maintaining flowability, effectively solving the problems of insufficient filling and slow curing of foamed materials. Attached Figure Description

[0017] 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 accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a flowchart of a method for preparing a composite foamed material provided in an embodiment of this application. Detailed Implementation

[0019] 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 some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application. Furthermore, it should be understood that the specific embodiments described herein are only for illustration and explanation of this application and are not intended to limit this application.

[0020] In this application, unless otherwise stated, directional terms such as "upper" and "lower" generally refer to the upper and lower positions of the device in its actual use or operating state, specifically the orientation shown in the accompanying drawings; while "inner" and "outer" refer to the outline of the device. Furthermore, in the description of this application, the term "comprising" means "including but not limited to". The terms first, second, third, etc., are used merely as illustrative purposes and do not impose numerical requirements or establish a numerical order.

[0021] In this application, "and / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. A and B can be singular or plural.

[0022] In this application, "at least one" means one or more, and "more than one" means two or more. "One or more", "at least one of the following", or similar expressions refer to any combination of these items, including any combination of single or multiple items. For example, "at least one of a, b, or c", or "at least one of a, b, and c" can both mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or multiple.

[0023] 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 this application; 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, regardless of the range. Furthermore, whenever a numerical range is referred to herein, it means including any referenced number (fraction or integer) within the referred range.

[0024] Existing foaming systems have several problems: low filling rate in ultra-thin-walled, narrow-channel refrigerator structures; difficulty in balancing environmental protection (GWP value) and energy saving (thermal conductivity, standby power consumption); large dimensional deformation rate at low temperatures, which can easily lead to cracking; and the technical problems of "flowability-curing speed-low temperature stability" have not been solved. The technical solution of this application solves at least one of the above problems.

[0025] The technical solution of this application is as follows: In a first aspect, embodiments of this application provide a composite foaming material, comprising a foaming agent composition, a polyol composition, and an isocyanate.

[0026] The blowing agent composition includes a gradient active unit, a low-temperature stabilizing unit, and a flow-aiding unit. The gradient active unit includes glycerol carbonate and hydroxyl-terminated polyether. The low-temperature stabilizing unit includes an organic-inorganic hybrid material. The flow-aiding unit includes an alkane blowing agent and a fluorinated olefin blowing agent.

[0027] The polyol composition includes polyether polyols.

[0028] It should be noted that hydroxyl-terminated polyethers refer to linear or slightly branched polymers whose main chain is composed of ether bonds and whose functional groups are hydroxyl groups at both ends or the ends of the molecular chain. Polyether polyols are high molecular weight compounds with a polyether structure as the main chain and containing multiple active hydroxyl (-OH) functional groups; they are environmentally friendly materials. Alkane blowing agents refer to blowing agents composed of alkyl compounds. Fluorinated olefin blowing agents refer to blowing agents containing fluorine groups and double bonds in an olefin structure.

[0029] The composite foaming material provided in this application includes a foaming agent composition comprising a gradient active unit, a low-temperature stabilizing unit, and a flow-aiding unit. The glycerol carbonate in the gradient active unit and the hydroxyl groups in the hydroxyl-terminated polyether can gradually react with isocyanate to generate polyurethane, thereby achieving the effect of "low activity in the early stage to maintain flow, and high activity in the later stage to promote curing." Furthermore, glycerol carbonate has an extremely low GWP (GWP < 1), making it environmentally friendly. The molecular structure of glycerol carbonate can form weak interactions with the polyurethane molecular chains, inserting itself between polymer chains, weakening the inter-chain interaction forces, and increasing the mobility of chain segments, thus making the foam softer and reducing its brittleness. The properties of the foam allow it to better recover its original shape after being compressed, and also prevent the foam from hardening and becoming brittle at low temperatures. Furthermore, the hydroxyl groups at the ends of the glycerol carbonate molecules impart reactivity, which can effectively reduce the viscosity of the system to a certain extent before foaming. This makes the mixing of the components more uniform, improves the flowability, facilitates filling, and reduces defects such as material shortages caused by poor flowability. The organic-inorganic hybrid material in the low-temperature stabilization unit can inhibit the shrinkage of the cells at low temperatures through chemical action. The alkane foaming agent in the flow aid unit provides a low thermal conductivity, and the fluorinated olefin foaming agent has good environmental performance. The combined viscosity of the two is low, which can improve the flowability of the system. The components of the foaming agent composition work synergistically to meet the filling and rapid demolding requirements of ultra-thin walls and narrow channels, improve the filling rate, and alleviate phenomena such as material shortage and shrinkage during foaming. The polyether polyol in the polyol composition, as one of the raw materials of polyurethane foam, has the characteristics of high functionality, fine cell structure and good dimensional stability, which can effectively improve the foam performance. The foaming agent composition and polyol composition in this application are compounded and mixed to promote curing while maintaining flowability, effectively solving the problems of insufficient filling and slow curing of foamed materials.

[0030] The composite foaming material provided in this application is used in the polyurethane foaming process, specifically the entire process of "nucleation-growth-curing". The synergistic mechanism of each component can be divided into two categories: intra-unit synergy and cross-unit synergy. The following is a detailed description of some of the synergistic interactions: (1) Synergistic mechanism of glycerol carbonate and hydroxyl-terminated polyether within the gradient active unit Reaction kinetic matching mechanism: The cyclic structure of glycerol carbonate results in low initial hydroxyl reactivity, while the linear hydroxyl activity of hydroxyl-terminated polyether is relatively stable. When combined, the initial reaction is dominated by a low-rate reaction between the polyether hydroxyl groups and isocyanate, maintaining low viscosity to ensure flowability. As the reaction progresses, the cyclic structure of glycerol carbonate opens and activates, causing a surge in hydroxyl activity, which rapidly crosslinks with the remaining isocyanate, achieving a seamless "flow-curing" sequence. The synergistic combination of glycerol carbonate and hydroxyl-terminated polyether avoids the problems of insufficient flow time or slow curing caused by single components, effectively improving the filling rate and shortening the demolding time.

[0031] The synergistic toughening mechanism of molecular chains: the short-chain structure formed after the ring-opening of glycerol carbonate inserts into the polyurethane backbone, weakening the hydrogen bond density between hard segments; the long-chain soft segments of hydroxyl-terminated polyether construct a flexible framework, and together they break the vicious cycle of "hard segment aggregation-low-temperature embrittlement". The synergy of the two can effectively improve the impact toughness of the foam and reduce the compression set.

[0032] (2) Synergistic mechanism of alkane blowing agent and fluorinated olefin blowing agent within the flow aid unit Viscosity and volatility balance mechanism: Alkane blowing agents have low viscosity but high volatility; when used alone, they are prone to cell collapse due to rapid evaporation. Fluorinated olefin blowing agents have higher viscosity but moderate boiling points, and the intermolecular polarity can inhibit the evaporation rate of alkane blowing agents. When the two are compounded in an appropriate ratio, the composite viscosity can be effectively controlled, and the volatility is matched with the bubble growth rate. The synergistic effect of alkane blowing agents and fluorinated olefin blowing agents can effectively improve the system's fluidity, increase the filling rate in narrow channels, and reduce shrinkage defects.

[0033] Environmental protection and energy conservation dual compliance mechanism: Alkane foaming agents have a high GWP and pose a greenhouse effect risk, while fluoroolefin foaming agents have a low GWP. When the two are combined, the overall GWP value can be controlled to be low. At the same time, the low thermal conductivity of alkane foaming agents and the thermal insulation of fluoroolefin foaming agents complement each other, resulting in a low overall thermal conductivity of foam, thus achieving a balance between low GWP environmental protection and energy efficiency.

[0034] (3) Cross-unit collaboration - the linkage mechanism between gradient active units and flow-aiding units Mechanism for extending the flow window: The viscosity-reducing effect of glyceryl carbonate and the low viscosity characteristics of the flow aid unit have a superimposed effect, which extends the low viscosity window time of the system at 5℃~20℃; at the same time, the "low activity in the early stage" characteristic of the gradient active unit avoids premature gelation and provides sufficient time for the flow aid unit to carry air bubbles to fill the narrow channel; the two work together to significantly reduce the material shortage defect in the ultrathin wall structure.

[0035] Curing and demolding synergistic mechanism: After the bubble growth of the flow aid unit reaches its peak, the gradient active unit enters the "late-stage high activity" stage, quickly forming a cross-linked network to lock the cell structure; at the same time, the fluorinated groups of the fluorinated olefin foaming agent can reduce the interfacial adhesion between the foam and the mold. The three work together to achieve a seamless connection between "filling-curing-demolding". The synergy of the two can effectively shorten the demolding time and improve the smoothness of the foam surface.

[0036] (4) Global coordination mechanism between the low-temperature stable unit and other units The mechanism of strengthening the cell structure: The introduction of organic groups in the organic-inorganic hybrid material allows them to form hydrogen bonds with the hydroxyl groups of glycerol carbonate, which are uniformly dispersed in the system and act as cell nucleation centers. At the same time, inorganic nanoparticles are adsorbed on the cell walls, which enhances the strain hardening ability of the melt and inhibits cell shrinkage at low temperatures.

[0037] Complementary mechanism for low-temperature performance: The segment toughening effect of glyceryl carbonate and the physical reinforcement effect of organic-inorganic hybrid materials form a "flexible-rigid" complementarity: the former increases the mobility of the segments to avoid embrittlement, while the latter inhibits the rupture of the cell walls through interfacial anchoring. Together, they enable the foam to maintain mechanical stability in the range of -40℃ to 60℃. The synergy of the two can meet the cross-temperature zone usage requirements of the freezer and refrigerator compartments of the refrigerator, effectively extending the service life.

[0038] (5) System-level synergistic mechanism between foaming agent combination and polyol composition Mechanism of cell fineness enhancement: The high functionality of the polyol composition can promote the formation of a dense cross-linked network, while the heterogeneous nucleation sites provided by the organic-inorganic hybrid material and the assisted nucleation effect of glycerol carbonate work together to refine the cell size, increase the cell closed-cell rate, further reduce the thermal conductivity of the foam, and improve the thermal insulation performance.

[0039] Reaction rate regulation mechanism: The active hydroxyl groups of polyether polyol and the hydroxyl groups of gradient active units form "dual active centers," resulting in a "stepwise increase" in the reaction rate with isocyanate: in the early stage, the reaction is dominated by the polyether polyol, ensuring flowability; in the later stage, the reaction is dominated by the hydroxyl groups after the ring-opening of glycerol carbonate, accelerating curing. The synergy of these two mechanisms effectively resolves the contradiction between "rapid curing during filling leading to material shortage" and "slow curing leading to delayed demolding," thereby improving production efficiency.

[0040] In the composite foaming material provided in this application embodiment, the components work together synergistically to solve the triangular contradiction of "flowability-curing property-low temperature stability" in ultra-thin wall and narrow channel scenarios through multiple mechanisms such as reaction timing matching, structural complementarity, and performance linkage: gradient active units and flow aid units ensure "filling ability", low temperature stable units and gradient active units ensure "stable filling", and polyol composition and foaming agent composition ensure "superior performance", ultimately achieving excellent comprehensive performance with high filling rate, short demolding time, and low shrinkage rate.

[0041] In some embodiments, the number average molecular weight of the hydroxyl-terminated polyether is 800-1200, for example, it can be 800, 900, 1000, 1100, 1200, or any range between two of the above values. Hydroxyl-terminated polyether is a key soft segment raw material in the manufacture of polyurethane. Within this number average molecular weight range, a suitable balance can be achieved between the mechanical strength, flexibility, and processing flowability of the polyurethane. Within this range, the polyether chains are long enough to effectively coil and move, forming a good elastic soft phase, while also exhibiting appropriate interaction with the hard phase, making the material both flexible and possessing sufficient strength and abrasion resistance.

[0042] In some embodiments, the mass ratio of glycerol carbonate to hydroxyl-terminated polyether in the gradient active unit is (1~3):1, for example, it can be 1:1, 1.5:1, 2:1, 2.5:1, 3:1, or any range between two of the above values. Within this mass ratio range, it is beneficial for the hydroxyl groups in the glycerol carbonate and hydroxyl-terminated polyether to react stepwise with the isocyanate to form polyurethane.

[0043] In some embodiments, the organic-inorganic hybrid material includes one or more of silane-modified silica, hydroxyapatite-grafted chitosan, and silane-modified nano-calcium carbonate. It should be noted that the inorganic materials in the organic-inorganic hybrid material are all at the nanoscale. For example, the average particle size of the silica in the silane-modified silica is 20 nm to 50 nm, such as 20 nm, 30 nm, 40 nm, 50 nm, or any range between two of the above values.

[0044] In some embodiments, the silanes in silane-modified silica and silane-modified nano-calcium carbonate are each independently selected from one or more of γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, and methyltrimethoxysilane.

[0045] It should be noted that suitable silanes can be selected for modification according to actual needs. For example, γ-aminopropyltriethoxysilane and γ-aminopropyltrimethoxysilane contain amino groups, which can optimize dispersion efficiency and interfacial bonding; γ-glycidoxypropyltrimethoxysilane contains epoxy groups, which can regulate reactivity and adapt to the "gradient curing" requirements; γ-mercaptopropyltrimethoxysilane contains mercapto groups, which can reduce system viscosity and improve filling properties; γ-methacryloyloxypropyltrimethoxysilane contains acryloyloxy groups, which can enhance the stability of the cell structure; methyltrimethoxysilane has no organotin dependence and is green and environmentally friendly.

[0046] In organic-inorganic hybrid materials, uniformly dispersed inorganic nanoparticles provide numerous low-energy-barrier nucleation sites for foam formation, resulting in a large and dense number of pores. This effectively inhibits excessive pore merging and coarsening, leading to a microporous structure with smaller pore size and more uniform distribution, reducing open pores and defects, and increasing closed-pore ratio. Furthermore, inorganic nanoparticles can migrate to the surface, forming a dense, heat- and oxygen-insulating ceramic-like protective layer. The organic materials in the organic-inorganic hybrid material have better compatibility with the matrix and can utilize hydrogen bonding to improve toughness. They can also more uniformly contribute to increasing the thermal decomposition temperature of the foam, thereby improving the low-temperature stability of the composite foam material.

[0047] In some embodiments, the alkane blowing agent includes one or more of cyclopentane and isopentane.

[0048] In some embodiments, the fluorinated olefin blowing agent includes one or more of 1-chloro-3,3,3-trifluoropropene (HFO-1233zd), 1,1,1,4,4,4-hexafluoro-2-butene (HFO-1336mzz), and 3,3,3-trifluoropropene (HFO-1243zf).

[0049] It should be noted that HFO-1233zd and HFO-1336mzz can be either cis or trans.

[0050] In some embodiments, the mass ratio of alkane blowing agent to fluorinated olefin blowing agent is (2~5):1, for example, it can be 2:1, 2.5:1, 3:1, 3.5:1, 4:1, 5:1, or any range between two of the above values. Within this mass ratio range, it is beneficial for the alkane blowing agent and the fluorinated olefin blowing agent to work together, reducing the viscosity of the composite foam material and improving its flowability.

[0051] In some embodiments, the viscosity of the flow aid unit is less than or equal to 50 mPa·s, for example, it can be less than or equal to 40 mPa·s, less than or equal to 30 mPa·s, less than or equal to 20 mPa·s, or less than or equal to 20 mPa·s. Within this viscosity range, the flow aid unit can improve the flowability of the composite foam material, thereby increasing the filling rate. It should be noted that the viscosity of the flow aid unit refers to the viscosity of the compound material of alkane foaming agent and fluorinated olefin foaming agent. It should also be noted that the viscosity of the flow aid unit is the viscosity at a temperature of 5℃ to 20℃.

[0052] In some embodiments, the mass ratio of the gradient active unit, the low-temperature stabilizing unit, and the flow-aiding unit is (30~50):(5~15):(35~65), for example, it can be 30:5:65, 35:8:57, 40:10:50, 45:12:43, 50:15:35, or any range between two of the above ratios. Within this mass ratio range, the components in the foaming agent composition work synergistically to meet the filling and rapid demolding requirements of ultra-thin-walled narrow channels.

[0053] In some embodiments, the isocyanate content (-NCO) in the isocyanate is 30% to 32%, and the insoluble content is less than or equal to 0.02%. This is beneficial for improving the solubility of the isocyanate and its reactivity with the hydroxyl groups in the gradient active units. It should be noted that insoluble matter refers to solid impurities or chemical byproducts in the isocyanate that are insoluble in a specified solvent (such as DMSO or ethyl acetate).

[0054] In some embodiments, the isocyanate includes one or more of polymethylene polyphenyl isocyanate, non-phosgene toluene diisocyanate (non-phosgene TDI), aliphatic isocyanate (ADI), and hydrogenated diphenylmethane diisocyanate (H12MDI).

[0055] In some embodiments, the mass ratio of the flow aid unit to the isocyanate is 1:(8~12), for example, it can be 1:8, 1:9, 1:10, 1:11, 1:12, or any range between two of the above ratios. Within this mass ratio range, it is beneficial for the foaming agent composition and the isocyanate to work synergistically to meet the filling and rapid demolding requirements of ultra-thin-walled narrow channels.

[0056] In some embodiments, the polyether polyol includes one or more of sucrose-glycerol polyether and bio-based polyether.

[0057] Furthermore, the hydroxyl value of sucrose-glycerol polyether is between 350 mg KOH / g and 450 mg KOH / g, for example, it can be 350 mg KOH / g, 380 mg KOH / g, 400 mg KOH / g, 420 mg KOH / g, 450 mg KOH / g, or any range between two of the above values. The hydroxyl value of bio-based polyether is also between 350 mg KOH / g and 450 mg KOH / g, for example, it can be 350 mg KOH / g, 380 mg KOH / g, 400 mg KOH / g, 420 mg KOH / g, 450 mg KOH / g, or any range between two of the above values. Within this range of hydroxyl values, the reaction between hydroxyl groups and isocyanates is favorable, thereby achieving the goal of good flowability in the early stage and rapid curing in the later stage of the composite foam material.

[0058] In some embodiments, the polyether polyol includes sucrose-glycerol polyether and bio-based polyether, and the mass ratio of sucrose-glycerol polyether to bio-based polyether is (3~5):1, for example, it can be 3:1, 3.5:1, 4:1, 4.5:1, 5:1, or any range between two of the above ratios. Within this mass ratio range, it is beneficial for the two polyether polyols to cooperate synergistically and jointly improve the performance of the composite foam material.

[0059] In some embodiments, the polyol composition further includes one or more of a catalyst, a surfactant, and an antioxidant.

[0060] In some embodiments, the catalyst includes one or more of amine catalysts and tin catalysts.

[0061] Furthermore, the amine catalyst includes one or more of pentamethyldiethylenetriamine, triethylenediamine, N,N-dimethylcyclohexylamine, bis(dimethylaminoethyl) ether, and dimethylethanolamine.

[0062] Tin-based catalysts include dibutyltin dilaurate.

[0063] Furthermore, the catalyst includes amine catalysts and tin catalysts, and the mass ratio of amine catalysts to tin catalysts is (0.5~2):1, for example, it can be 0.5:1, 0.8:1, 1:1, 1.2:1, 1.5:1, 1.8:1, 2:1, or any range between two of the above ratios. Within this mass ratio range, the amine catalyst mainly maintains flow in the early stage, and the tin catalyst accelerates cross-linking and curing in the later stage.

[0064] In some embodiments, the surfactant includes one or more of polyether-modified organosilicon, organosilicon-polyamide copolymer, polyetheramine-modified silicone oil, and fatty alcohol polyoxyethylene ether. It should be noted that the polyether-modified organosilicon is a polyether-siloxane copolymer prepared from the polyether segment of a siloxane molecule.

[0065] Furthermore, polyether-modified organosilicon can be introduced by adding an aqueous solution of polyether-modified organosilicon, wherein the aqueous solution of polyether-modified organosilicon has a pH value of 6~8 and a surface tension of 22mN / m~24mN / m, which can effectively reduce the liquid-gas interfacial tension and reduce the merging of bubbles in narrow channels.

[0066] In some embodiments, the antioxidant includes hindered phenolic antioxidants.

[0067] Furthermore, hindered phenolic antioxidants include one or more of antioxidants 1010, 702, 2246, 1076, and 5057. Antioxidants can improve the stability of composite foam materials.

[0068] In some embodiments, the mass ratio of polyether polyol, catalyst, surfactant, and antioxidant is (60~80):(2~5):(1~3):(0.5~1.5), for example, it can be 60:5:1:1.5, 65:4:1.5:1.2, 70:3:2:1, 75:2:2.5:0.8, 80:5:3:0.5, or any range between two of the above ratios. Within this mass ratio range, the components in the polyol composition cooperate with each other, which is beneficial to further control the viscosity and flowability of the system, making it easy for the composite foam material to flow when flow is required, and to quickly crosslink and cure when curing is required.

[0069] In some embodiments, the mass ratio of the flow aid unit to the isocyanate and to the polyol composition is (1.2~1.5):1, for example, it can be 1.2:1, 1.3:1, 1.4:1, 1.5:1, or any range between the above two values. Within this mass ratio range, it is beneficial for the components of the composite foam material to work synergistically to improve the performance of the composite foam material.

[0070] In some embodiments, the average diameter of the pores formed by the foaming of the composite foam material is 50 μm to 150 μm, for example, it can be 50 μm, 80 μm, 100 μm, 120 μm, 150 μm, or any range between two of the above values. With this average pore diameter, the composite foam material is lightweight and convenient, with fine pores, effectively providing thermal insulation and reducing heat transfer.

[0071] Secondly, please refer to Figure 1 This application also provides a method for preparing a composite foamed material, comprising the following steps: Step S11: Provide a flow aid unit and isocyanate, mix them, and obtain a premix; Step S12: Mix the premix, polyol composition, gradient active unit, and low-temperature stable unit to obtain foaming stock solution; Step S13: Inject the foaming liquid into the mold and foam to obtain the composite foam material.

[0072] The gradient active unit includes glycerol carbonate and hydroxyl-terminated polyether. The low-temperature stabilizing unit includes an organic-inorganic hybrid material. The flow aid unit includes an alkane blowing agent and a fluorinated olefin blowing agent. The polyol composition includes a polyether polyol.

[0073] The materials and dosages of the flow aid unit, isocyanate, polyol composition, gradient active unit, and low-temperature stable unit can be found above and will not be repeated here.

[0074] This method first mixes the flow aid unit and isocyanate to form a premix. Subsequent mixing with other components avoids localized reaction imbalances caused by uneven dispersion, ensuring uniform foam performance. If all components are mixed at once, the isocyanate will react rapidly with the hydroxyl groups, potentially causing premature gelation, shortening the flow window, and failing to fill narrow channels. Furthermore, the viscosity-reducing effect of the flow aid unit cannot be preferentially utilized during one-time mixing. Direct mixing of isocyanate with high-viscosity polyols leads to a sharp increase in system viscosity, decreased flowability, and incomplete filling. One-time mixing may also cause isocyanate to simultaneously come into contact with water (in trace amounts in the raw material) and hydroxyl groups, making the reaction more complex, easily generating more insoluble substances, and disrupting cell uniformity. This method, by mixing in batches according to the characteristics of the raw materials, facilitates uniform mixing of all components and ensures that the system's reaction and viscosity are in suitable states, making it easier to prepare high-performance foamed materials.

[0075] In some embodiments, the mixing temperature of the flow aid unit and the isocyanate is 3°C to 10°C, for example, 3°C, 4°C, 5°C, 6°C, 7°C, 8°C, 9°C, 10°C, or any range between two of the above values; the mixing time is 10s to 15s, for example, 10s, 11s, 12s, 13s, 14s, 15s, or any range between two of the above values. Under these mixing conditions, it is beneficial to suppress premature reaction of the isocyanate. The flow aid unit can first mix and encapsulate the isocyanate, reducing its direct contact with the hydroxyl groups in the subsequent polyols and gradient active units, thus avoiding a sudden increase in viscosity or the formation of impurities caused by premature reaction.

[0076] In some embodiments, the viscosity of the premix is ​​less than or equal to 80 mPa·s, for example, less than or equal to 70 mPa·s, less than or equal to 60 mPa·s, less than or equal to 50 mPa·s, less than or equal to 40 mPa·s, less than or equal to 30 mPa·s, etc. Within this viscosity range, the premix exhibits good flowability, facilitating uniform contact and mixing with subsequent materials. It is understood that the low viscosity of isocyanates results in a low premix viscosity, ensuring flowability and suitability for narrow-channel filling. It should be noted that the viscosity of the premix refers to its viscosity at 5°C to 10°C.

[0077] In some embodiments, mixing the premix and the polyol composition, the gradient active unit, and the low-temperature stabilizing unit includes stirring.

[0078] Furthermore, the stirring speed is 3000 rpm to 4000 rpm, for example, 3000 rpm, 3200 rpm, 3500 rpm, 3800 rpm, 4000 rpm, or any range between two of the above values; the stirring time is 5 s to 8 s, for example, 5 s, 6 s, 7 s, 8 s, or any range between two of the above values. Under these stirring conditions, it is beneficial for the components to fully contact and mix, improving the uniformity of the composite foam material after the subsequent foaming reaction.

[0079] In some embodiments, the pressure at which the foaming agent is injected into the mold is 0.3MPa to 0.5MPa, for example, it can be 0.3MPa, 0.35MPa, 0.4MPa, 0.45MPa, 0.5MPa or any range between two of the above values.

[0080] The temperature of the mold is 40℃~45℃, for example, it can be 40℃, 41℃, 42℃, 43℃, 44℃, 45℃ or any two of the above values.

[0081] The holding time after the foaming liquid is injected into the mold is 25s to 60s, for example, it can be 25s, 30s, 40s, 50s, 60s or any range between two of the above values.

[0082] Thus, under the aforementioned foaming conditions, the combination of "low-pressure rapid injection and medium-temperature pressure holding" avoids local overheating caused by the foaming solution remaining in narrow channels, effectively improving the uniformity of the foam cells.

[0083] It should be noted that after pressure holding, the foam is demolded, and a certain amount of post-curing can be carried out after demolding to improve the mechanical properties and stability of the foam. The post-curing time can be 20h~30h.

[0084] It should also be noted that molds with suitable structures and sizes can be selected based on the renewal period.

[0085] In some embodiments, the wall thickness of the mold is 8mm to 15mm, for example, it can be 8mm, 10mm, 12mm, 14mm, 15mm or any range between two of the above values; the channel width of the mold is 5mm to 8mm, for example, it can be 5mm, 6mm, 7mm, 8mm or any range between two of the above values. The mold selected in this embodiment is an ultra-thin-walled, narrow-channel mold, which can meet the requirements of lightweighting the refrigerator body and increase the usable space of the refrigerator.

[0086] Thirdly, embodiments of this application also provide a refrigerator, which includes a cabinet, and the interlayer of the cabinet is provided with the above-mentioned composite foaming material, or the foaming material prepared by the above-mentioned preparation method.

[0087] The composite foaming material of this application can be used in refrigerators to achieve lightweight, low-energy consumption and high-efficiency production of refrigerator bodies, meeting the development needs of the refrigerator industry for green environmental protection and energy conservation.

[0088] The present application will be specifically described below through specific embodiments. The following embodiments are only some embodiments of the present application and are not intended to limit the present application.

[0089] Example 1 This embodiment provides a composite foaming material, which includes a foaming agent composition, a viscosity control system, and an isocyanate.

[0090] The foaming agent composition includes: Gradient active unit: a mixture of glyceryl carbonate (purity ≥99%) and hydroxyl-terminated polyether (molecular weight 1000) at a mass ratio of 2:1. Low-temperature stable unit: γ-aminopropyltriethoxysilane modified nano-silica, average particle size 30nm, modification degree 80%). Flow aid unit (cyclopentane and cis-HFO-1233zd mixed at a mass ratio of 3:1); The mass ratio of the gradient active unit, the low-temperature stabilizing unit, and the flow-aiding unit is 40:10:50.

[0091] The viscosity control system includes: 60 parts of sucrose-glycerol polyether (hydroxyl value 400 mg KOH / g), 20 parts of bio-based polyether (hydroxyl value 250 mg KOH / g), 3 parts of catalyst (a mixture of pentamethyldiethylenetriamine and dibutyltin dilaurate in a mass ratio of 1:1), 2 parts of surfactant (polyether-modified organosilicon), and 1 part of antioxidant (antioxidant 1010).

[0092] Isocyanates include: polymethylene polyphenyl isocyanate (-NCO content 31%, insoluble matter content 0.015%).

[0093] The preparation method of composite foamed materials is as follows: Step S21: Add polymethylene polyphenyl isocyanate and the flow aid unit to the static mixer at a mass ratio of 10:1, control the premixing temperature at 8°C, mix for 10 seconds, and obtain the premix. Step S22: Mix the premix with the viscosity control system at a mass ratio of 1.3:1, and simultaneously add the gradient active unit and the low temperature stable unit. Stir at 4000 rpm for 8 seconds to obtain the foaming stock solution. Step S23: Inject the foaming liquid into an ultra-thin wall narrow channel mold (wall thickness 10mm, channel width 6mm) under a pressure of 0.4MPa. The mold temperature is 42℃. After holding the pressure for 45s, demold and cure for 24h to obtain the composite foaming material.

[0094] Example 2 This embodiment is basically the same as that of Embodiment 1, except that the mass ratio of the gradient active unit, the low temperature stabilizing unit and the flow aid unit in the foaming agent composition of this embodiment is 30:15:55.

[0095] Example 3 This embodiment is basically the same as Embodiment 1, except that the mass ratio of the gradient active unit, the low temperature stabilizing unit and the flow aid unit in the foaming agent composition of this embodiment is 50:5:45.

[0096] Example 4 This embodiment is basically the same as Embodiment 1, except that in the gradient active unit of this embodiment, glyceryl carbonate and hydroxyl-terminated polyether are mixed at a mass ratio of 1:1.

[0097] Example 5 This embodiment is basically the same as Example 1, except that the catalyst is in 2 parts in the viscosity control system of this embodiment.

[0098] Example 6 This embodiment is basically the same as embodiment 1, except that in step S21, the premixing temperature is 10°C, and in step S23, the foaming liquid injection pressure is 0.5MPa, the mold temperature is 45°C, and the holding time is 60s.

[0099] Comparative Example 1 This comparative example is basically the same as Example 1, except that the gradient active unit in this comparative example only includes glycerol carbonate and does not contain hydroxyl-terminated polyether.

[0100] Comparative Example 2 This comparative example is basically the same as Example 1, except that the viscosity control system in this comparative example includes: 80 parts of sucrose-glycerol polyether (hydroxyl value 400mgKOH / g), 3 parts of catalyst (pentamethyldiethylenetriamine), 2 parts of surfactant (polyether modified organosilicon), and 1 part of antioxidant (antioxidant 1010).

[0101] Comparative Example 3 This comparative example is basically the same as Example 1, except that in step S21, the premixing temperature is 25°C, and in step S23, the foaming liquid injection pressure is 0.1 MPa, the mold temperature is 35°C, and the holding time is 20 s.

[0102] Comparative Example 4 The composite foaming material in this comparative example includes: 89.2 parts of polyol components (29 parts of sucrose polyether polyol, 25 parts of sorbitol polyether polyol, 15 parts of glycerol polyether polyol, 8 parts of aromatic amine polyether polyol, 5 parts of polyester polyol, 4.3 parts of foam stabilizer Tegostab B8476, and 2.9 parts of catalyst pentamethyldiethylenetriamine), 28.5 parts of foaming agent combination (cyclopentane, glycerol carbonate, n-butane, and water in a mass ratio of 16:9.8:1.7:1), and 126 parts of organic isocyanate (Lupranate M20s).

[0103] Comparative Example 5 The composite foaming material in this comparative example includes: 20 parts of isocyanate (140 parts of polymethylene polyphenyl isocyanate and 20 parts of propylene glycol polyether modified polymethylene polyphenyl isocyanate) and 1 part of foaming agent (5 parts of isopentane and 3 parts of n-butane).

[0104] Comparative Example 6 The composite foaming material in this comparative example includes cyclopentane.

[0105] Comparative Example 7 The composite foaming material in this comparative example includes glyceryl carbonate.

[0106] The filling rate, thermal conductivity (10℃), and low-temperature dimensional deformation rate (-30℃, 24h) of the composite foam materials in Examples 1-4 and Comparative Examples 1, 4-7 were tested. The test results are shown in Table 1.

[0107] The filling rate was tested in accordance with GB / T 6342-2009; the thermal conductivity was tested in accordance with GB / T 10294-2008 (protective hot plate method); and the low-temperature dimensional deformation rate was tested in accordance with GB / T 15585-1995.

[0108] Table 1

[0109] From Table 1, we can obtain: The composite foam material provided in this application has a filling rate ≥95.5%, a thermal conductivity ≤18.1mW / (m•K), and a low-temperature deformation rate ≤0.5%, which is significantly better than Comparative Example 1 and Comparative Examples 4-7 using pure glycerol carbonate. The components in the composite foam material of this application work synergistically to improve the filling rate of the composite material, reduce the thermal conductivity, and reduce the deformation rate at low temperatures, thereby improving its thermal insulation performance and stability at low temperatures.

[0110] The initial viscosity of the foaming agent in the composite foaming materials of Examples 1 and 5 and Comparative Example 2 at 25°C, the viscosity changes after 30s and 80s, and the corresponding curing time (the time required for the initial cross-linked structure with demolding strength to be formed after the foaming agent is injected, to ensure that the foam can be removed from the mold in time after molding, and to avoid sticking or deformation) were tested. The test results are shown in Table 1.

[0111] The viscosity was tested according to GB / T 10247-2008 "Viscosity Measurement Method"; the curing time was tested according to HG / T4574-2014 "Determination of Foaming Reaction Characteristics of Polyurethane Raw Materials".

[0112] Table 2

[0113] From Table 2, we can obtain: The embodiments of this application employ a suitable combination of catalysts, resulting in a dynamic change in the viscosity of the foaming stock solution, characterized by "low viscosity in the early stage and high viscosity in the later stage." The low viscosity in the early stage indicates strong fluidity, which can effectively flow and fill, reducing the existence of gaps and voids. The rapid increase in viscosity in the later stage helps to shorten the curing time and improve the curing efficiency.

[0114] The filling rate and uniformity of the foamed cells in Examples 1 and 6 and Comparative Example 3 of composite foamed materials were tested. The test results are shown in Table 3.

[0115] Among them, the uniformity of the bubble cells was tested in accordance with GB / T 6343-2009.

[0116] Table 3

[0117] From Table 3, we can obtain: The embodiments of this application adopt a preparation process of "low temperature premixing, medium pressure injection and medium temperature holding pressure". The composite foam material prepared by controlling the appropriate conditions has a filling rate of ≥95% and a cell uniformity of ≥92%, which is significantly better than that of Comparative Example 3. This shows that the composite foam material prepared by this method has more uniform performance and better quality.

[0118] The composite foaming material provided in this application embodiment effectively improves the foaming filling rate through the synergy of the foaming agent composition and the polyol composition, solving the "material shortage" problem in the lightweight design of refrigerators. It can be adapted to ultra-thin walls and narrow channels to meet the requirements of lightweighting. The composite foaming material is green and environmentally friendly, with a low GWP value and low thermal conductivity, which helps to reduce refrigerator energy consumption and promote energy conservation and emission reduction. The low-temperature dimensional deformation rate can prevent the ultra-thin wall structure from cracking under temperature changes, improve stability, and extend the service life of the refrigerator. The composite foaming material has a short curing time and high demolding efficiency in the preparation process, which is conducive to cost reduction and efficiency improvement.

[0119] The technical solutions provided by the embodiments of this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the method 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 composite foaming material, characterized in that, Includes foaming agent compositions, polyol compositions, and isocyanates; The foaming agent composition comprises a gradient active unit, a low-temperature stabilizing unit, and a flow aid unit; the gradient active unit comprises glycerol carbonate and hydroxyl-terminated polyether; the low-temperature stabilizing unit comprises an organic-inorganic hybrid material; and the flow aid unit comprises an alkane foaming agent and a fluorinated olefin foaming agent. The polyol composition includes polyether polyols.

2. The composite foamed material as described in claim 1, characterized in that, The organic-inorganic hybrid material includes one or more of silane-modified silica, hydroxyapatite-grafted chitosan, and silane-modified nano-calcium carbonate. The alkane blowing agent includes one or more of cyclopentane and isopentane; The fluorinated olefin blowing agent includes one or more of 1-chloro-3,3,3-trifluoropropene, 1,1,1,4,4,4-hexafluoro-2-butene, and 3,3,3-trifluoropropene; In the gradient active unit, the mass ratio of the glycerol carbonate to the hydroxyl-terminated polyether is (1~3):1; In the flow aid unit, the mass ratio of the alkane blowing agent to the fluorinated olefin blowing agent is (2~5):

1.

3. The composite foamed material as described in claim 1, characterized in that, The isocyanate contains 30% to 32% isocyanate and has an insoluble content of less than or equal to 0.02%. The isocyanate includes one or more of polymethylene polyphenyl isocyanate, nonphosgene toluene diisocyanate, aliphatic isocyanate, and hydrogenated diphenylmethane diisocyanate. The mass ratio of the flow aid unit to the isocyanate is 1:(8~12). The mass ratio of the flow aid unit to the isocyanate and to the polyol composition is (1.2~1.5):

1.

4. The composite foamed material as described in claim 1, characterized in that, The polyether polyol includes one or more of sucrose-glycerol polyether and bio-based polyether; wherein... The hydroxyl value of the sucrose-glycerol polyether is 350 mg KOH / g to 450 mg KOH / g; The hydroxyl value of the bio-based polyether is 350 mg KOH / g to 450 mg KOH / g; The mass ratio of the sucrose-glycerol polyether to the bio-based polyether is (3~5):

1.

5. The composite foamed material as described in claim 1, characterized in that, The polyol composition also includes one or more of a catalyst, a surfactant, and an antioxidant.

6. The composite foamed material as described in claim 5, characterized in that, The catalyst includes one or more of amine catalysts and tin catalysts; optionally, the amine catalyst includes one or more of pentamethyldiethylenetriamine, triethylenediamine, N,N-dimethylcyclohexylamine, bis(dimethylaminoethyl) ether, and dimethylethanolamine; the tin catalyst includes dibutyltin dilaurate; optionally, the mass ratio of the amine catalyst to the tin catalyst is (0.5~2):1; The surfactant includes one or more of polyether-modified silicone, silicone-polyamide copolymer, polyetheramine-modified silicone oil, and fatty alcohol polyoxyethylene ether; The antioxidants include hindered phenolic antioxidants; hindered phenolic antioxidants include one or more of antioxidants 1010, antioxidant 702, antioxidant 2246, antioxidant 1076, and antioxidant 5057. The mass ratio of the polyether polyol, catalyst, surfactant and antioxidant is (60~80):(2~5):(1~3):(0.5~1.5).

7. The composite foamed material as described in claim 1, characterized in that, The mass ratio of the gradient active unit, the low-temperature stabilizing unit, and the flow-aiding unit is (30~50):(5~15):(35~65); The average diameter of the pores formed by the foaming of the composite foam material is 50μm~150μm.

8. A method for preparing a composite foamed material, characterized in that, Includes the following steps: A flow aid unit and isocyanate are provided, mixed, and a premix is ​​obtained; The premix, polyol composition, gradient active unit, and low-temperature stable unit are mixed to obtain foaming stock solution; The foaming solution is injected into a mold to foam, thus obtaining a composite foamed material. The gradient active unit comprises glycerol carbonate and hydroxyl-terminated polyether; the low-temperature stable unit comprises an organic-inorganic hybrid material; the flow aid unit comprises an alkane blowing agent and a fluorinated olefin blowing agent; and the polyol composition comprises a polyether polyol.

9. The preparation method according to claim 8, characterized in that, The mixing temperature of the flow aid unit and the isocyanate is 3℃~10℃, and the mixing time is 10s~15s; The viscosity of the premix is ​​less than or equal to 80 mPa·s; The premix, the polyol composition, the gradient active unit, and the low-temperature stable unit are mixed and then stirred; optionally, the stirring speed is 3000 rpm to 4000 rpm, and the stirring time is 5 s to 8 s. The pressure at which the foaming liquid is injected into the mold is 0.3MPa~0.5MPa, the temperature of the mold is 40℃~45℃, and the pressure holding time after the foaming liquid is injected into the mold is 25s~60s.

10. A refrigerator, characterized in that, The container includes a housing, the interlayer of which is provided with the composite foam material as described in any one of claims 1 to 7, or includes the composite foam material prepared by the preparation method as described in any one of claims 8 to 9.

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