A lightweight thermal insulation composite material and its preparation method

Abstract

This invention specifically relates to a lightweight thermal insulation composite material and its preparation method. The lightweight thermal insulation composite material comprises the following raw materials in parts by weight: 70-85 parts of ethylene-vinyl acetate copolymer, 5-15 parts of aerogel, 4-12 parts of polyethylene, 4-10 parts of polyolefin elastomer, 2-8 parts of thermoplastic polyurethane, and 0.1-10 parts of compatibilizer, or further comprising 4-10 parts of ethylene propylene diene monomer (EPDM) rubber, 5-10 parts of foaming agent, and 0.5-6 parts of additives. This invention, by compounding ethylene-vinyl acetate copolymer, polyethylene, polyolefin elastomer, and thermoplastic polyurethane, and combining them with aerogel, imparts a low thermal conductivity to the material, enabling the resulting lightweight thermal insulation composite material to maintain good resilience and dimensional stability.

Description

Technical Field

[0001] This invention relates to the field of thermal insulation materials technology, specifically to a lightweight thermal insulation composite material and its preparation method. Background Technology

[0002] Balancing lightweight design with high-efficiency thermal insulation performance is one of the core requirements in the field of energy conservation and environmental protection. As the requirements for thermal insulation materials in high-end building materials, cold chain transportation, electronic packaging and other scenarios continue to increase, materials not only need to have low thermal conductivity, but also need to be lightweight, highly resilient and have excellent dimensional stability to adapt to complex usage environments.

[0003] In existing technologies, foamed materials made primarily of ethylene-vinyl acetate copolymer are commonly used to achieve a basic balance between thermal insulation and mechanical properties. However, the thermal insulation performance of these materials mainly relies on the micron-sized closed-cell structure formed by foaming. Although this suppresses air convection heat transfer, their thermal conductivity is still insufficient to meet the requirements of high-precision insulation applications. Furthermore, simply increasing the foaming ratio to reduce material density leads to a decrease in cell wall thickness, resulting in reduced material mechanical strength and resilience. This results in lightweight materials with reduced strength and durability, limiting their application in scenarios requiring structural stability. Therefore, developing thermal insulation composite materials with low thermal conductivity, lightweight properties, and high durability through the synergistic effect of aerogels and foamed materials is of great significance. Summary of the Invention

[0004] In order to overcome the shortcomings and deficiencies of the existing technology, the purpose of this invention is to provide a lightweight thermal insulation composite material, which has the advantages of low thermal conductivity, light weight and softness, good resilience and excellent weather resistance.

[0005] Another objective of this invention is to provide a method for preparing lightweight thermal insulation composite materials. This method allows for the selection of a suitable supercritical foaming process or chemical foaming process based on the characteristics of the formulation. It is simple to operate and easy to industrialize.

[0006] The objective of this invention is achieved through the following technical solution: a lightweight thermal insulation composite material comprising the following raw materials in parts by weight: 70-85 parts of ethylene-vinyl acetate copolymer, 5-15 parts of aerogel, 4-12 parts of polyethylene, 4-10 parts of polyolefin elastomer, 2-8 parts of thermoplastic polyurethane, and 0.1-10 parts of compatibilizer.

[0007] This invention uses ethylene-vinyl acetate copolymer, polyethylene, polyolefin elastomer, and thermoplastic polyurethane to form a composite material system with low thermal conductivity, lightweight, flexibility and high resilience. The aerogel is introduced and the raw materials work synergistically.

[0008] Furthermore, the aerogel is at least one of silica aerogel, alumina aerogel, carbon aerogel, and organic aerogel. The aerogel is preferably silica aerogel. The aerogel, in synergy with a multi-component polymer matrix such as ethylene-vinyl acetate copolymer, polyethylene, polyolefin elastomer, and thermoplastic polyurethane, forms a hierarchical porous structure with micron-level closed pores and nano-level pores through foaming, achieving a balance between low thermal conductivity and lightweight.

[0009] Furthermore, the compatibilizer is at least one of maleic anhydride-grafted polyolefin elastomer, polysiloxane-modified polyurethane, and silane coupling agent.

[0010] Furthermore, the lightweight thermal insulation composite material also includes the following raw materials in parts by weight: 4-12 parts of EPDM rubber, 5-10 parts of foaming agent, and 0.5-6 parts of additives.

[0011] Furthermore, the foaming agent is at least one selected from azodicarbonamide, azobisisobutyronitrile, and 4,4'-oxobisbenzenesulfonylhydrazine. The preferred foaming agent is azodicarbonamide, which has the advantages of high gas evolution and controllable decomposition temperature.

[0012] Furthermore, the additive is at least one of zinc oxide, crosslinking agent, and flow agent.

[0013] Furthermore, the additives include the following raw materials in parts by weight: 0.4-2 parts zinc oxide, 0.5-2 parts crosslinking agent, and 0.1-2 parts flow agent.

[0014] Furthermore, the crosslinking agent is at least one selected from dicumyl peroxide, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, bis-tert-butylperoxyisopropylbenzene, benzoyl peroxide, and di-tert-butyl peroxide.

[0015] Furthermore, the flow agent is at least one of fatty acids, fatty acid metal salts, fatty acid esters, fatty acid amides, hydrocarbon waxes, and metal soaps.

[0016] Furthermore, the flow agent is at least one selected from stearic acid, zinc stearate, and polyethylene wax. The flow agent can reduce melt viscosity, improve processing fluidity, and also serve as a release agent.

[0017] This invention introduces aerogel into a composite system of ethylene-vinyl acetate copolymer, polyethylene, polyolefin elastomer, and thermoplastic polyurethane. Through supercritical or chemical foaming processes, a micron-scale closed-pore structure is formed within the polymer matrix. Simultaneously, the aerogel particles themselves possess a nanoscale pore structure, together forming a hierarchical pore structure with nested micron and nanopores. This structure effectively suppresses relative heat transfer between air and solid phases, significantly reducing the material's thermal conductivity. Furthermore, the aerogel acts as a heterogeneous nucleation site during foaming, increasing the cell nucleation density and resulting in finer, more uniform cells. The aerogel particles, embedded in the cell walls, provide support through their rigid framework, effectively reducing material density while mitigating the loss of mechanical properties caused by density reduction. This allows the composite material to maintain good compressive strength and dimensional stability, overcoming the defect in existing foamed materials where density reduction leads to decreased mechanical properties.

[0018] Another object of the present invention is to provide a method for preparing a lightweight thermal insulation composite material, which employs a supercritical foaming process and includes the following steps: S1 Weigh out each ingredient according to the formula and mix them evenly; S2 adds the mixed material to the extruder for melt extrusion; S3 places the extrudate in a foaming device, fills it with nitrogen and carbon dioxide, and performs one foaming process. The foaming temperature is 75-85℃ and the foaming time is 90-150 minutes. S4 is depressurized to atmospheric pressure, then nitrogen and carbon dioxide are introduced for secondary foaming. The foaming temperature is 110-130℃ and the foaming time is 30-90 minutes. S5 cuts the obtained sheet into sections to obtain a lightweight thermal insulation composite sheet.

[0019] Furthermore, in step (2), the temperatures of each zone of the melt extrusion using a twin-screw extruder are: Zone 1 110-120℃; Zone 2 115-125℃; Zone 3 120-130℃; and the die temperature is 110-130℃.

[0020] The above temperature settings can ensure that all components are fully plasticized and melted, and can also avoid the degradation of heat-sensitive components, providing a uniform melt for subsequent supercritical foaming.

[0021] The supercritical foaming process of the lightweight thermal insulation composite material of the present invention uses nitrogen and carbon dioxide as physical foaming agents, with no chemical residues throughout the process and excellent environmental performance. Through a first low-temperature foaming and a second high-temperature foaming, a large number of uniform microbubble nuclei are first formed at a lower temperature, and then they are allowed to grow stably at a higher temperature, thereby obtaining a foamed material with high closed-cell rate and uniform and dense cell structure.

[0022] This invention also provides another method for preparing a lightweight thermal insulation composite material, which employs a chemical foaming process and includes the following steps: S1 Weigh out each ingredient according to the formula and mix them evenly; S2 The mixed materials are then subjected to intensive mixing at a temperature of 110-130℃ for 10-20 minutes. S3 refines the mixed material at a temperature of 110-130℃ for 5-15 minutes. S4 involves adding the refined material into an extruder for melt extrusion; S5 Place the extrudate in a foaming device and foam it once. The foaming temperature is 130-150℃ and the time is 20-40 minutes. S6 undergoes secondary foaming at a temperature of 160-170℃ for 30-90 minutes. S7 cuts the obtained sheet into sections to obtain a lightweight thermal insulation composite material.

[0023] Furthermore, in step S4, the temperatures of each zone during melt extrusion using a twin-screw extruder are: zone 1 90-95℃, zone 2 92-100℃, zone 3 95-100℃, and the die temperature is 90-100℃. These temperature settings help ensure the material is fully melted and plasticized, and effectively prevent premature decomposition of the chemical foaming agent during extrusion.

[0024] The chemical foaming process of this invention is applicable to reinforced formulation systems containing EPDM rubber and additives. Through mixing and refining processes, the components, such as the EPDM rubber phase, achieve good dispersion and compatibility with the resin phase composed of ethylene-vinyl acetate copolymer, polyethylene, polyolefin elastomer, and thermoplastic polyurethane. Taking advantage of the decomposition characteristics of the chemical foaming agent, a higher-temperature secondary foaming process is employed, allowing the material to complete the cross-linking reaction during foaming, forming a stable three-dimensional network structure.

[0025] Furthermore, after the supercritical foaming process or chemical foaming process is completed, the obtained sheet is slit. The slit thickness can be flexibly selected according to the actual application requirements, preferably 0.5-5mm.

[0026] Furthermore, after the supercritical foaming process or chemical foaming process of the lightweight thermal insulation composite material is completed, the lightweight thermal insulation composite material is punctured using a needle pressing device. The puncture gap is 0.5-1cm and the puncture diameter is 0.01-0.03mm.

[0027] This invention creates perforations in a lightweight thermal insulation composite material, forming breathable pores that penetrate both sides of the fabric. Based on the thermal expansion and contraction properties of polymer materials, when the ambient temperature is low, the fabric matrix shrinks, the pore size decreases, and breathability is reduced, thus minimizing heat loss. When the ambient temperature is high, the fabric matrix expands, the pore size increases, and breathability is enhanced, facilitating moisture wicking and heat dissipation. This gives the fabric a breathability regulation function, allowing it to adjust its breathability according to the ambient temperature, thereby improving wearing comfort.

[0028] The beneficial effects of this invention are as follows: By compounding ethylene-vinyl acetate copolymer, polyethylene, polyolefin elastomer, and thermoplastic polyurethane, and combining them with aerogel, a multi-level porous structure with micron-scale closed-cell and nano-scale aerogel pores is formed, giving the material a low thermal conductivity. The introduction of aerogel helps to reduce the density of the composite material and improve its lightweight nature. At the same time, the rigid skeleton structure of the aerogel embedded in the cell walls can alleviate the decline in mechanical properties caused by low density, enabling the resulting lightweight thermal insulation composite material to maintain good resilience and dimensional stability.

[0029] This invention further combines ethylene-vinyl acetate copolymer, polyethylene, polyolefin elastomer, thermoplastic polyurethane and EPDM rubber, and combines them with aerogel, which helps to improve the resilience, weather resistance and dimensional stability of the composite material.

[0030] This invention provides supercritical physical foaming and chemical foaming processes for different formulation characteristics of lightweight thermal insulation composite materials. The supercritical process uses nitrogen and carbon dioxide as foaming agents, making it environmentally friendly. The chemical foaming process, through mixing, refining, and secondary foaming, achieves good compatibility and uniform dispersion of the components, exhibiting strong process adaptability. Attached Figure Description

[0031] Figure 1 This is a state diagram of the air permeability test of the lightweight thermal insulation composite material of the present invention after pore pressing. Detailed Implementation

[0032] To facilitate understanding by those skilled in the art, the present invention will be further described below with reference to embodiments. The content mentioned in the embodiments is not intended to limit the present invention.

[0033] In some embodiments of the present invention, a lightweight thermal insulation composite material comprises the following raw materials in parts by weight: 70-85 parts of ethylene-vinyl acetate copolymer, 5-15 parts of aerogel, 4-12 parts of polyethylene, 4-10 parts of polyolefin elastomer (POE), 2-8 parts of thermoplastic polyurethane (TPU), and 0.1-10 parts of compatibilizer.

[0034] In some embodiments of the present invention, the aerogel is at least one selected from silica aerogel, alumina aerogel, carbon aerogel, and organic aerogel. Preferably, the silica aerogel is a hydrophobic silica aerogel.

[0035] In some embodiments of the present invention, the silica aerogel has a particle size of 1-50 μm and a specific surface area of ​​500-1000 m². 2 / g.

[0036] In some embodiments of the present invention, the compatibilizer is at least one of maleic anhydride-grafted polyolefin elastomer, polysiloxane-modified polyurethane, and silane coupling agent.

[0037] In some embodiments of the present invention, a lightweight thermal insulation composite material comprises the following raw materials in parts by weight: 70-85 parts of ethylene-vinyl acetate copolymer, 5-15 parts of aerogel, 4-12 parts of polyethylene, 4-10 parts of polyolefin elastomer, 2-8 parts of thermoplastic polyurethane, and 0.5-6 parts of compatibilizer.

[0038] In some embodiments of the present invention, a lightweight thermal insulation composite material comprises the following raw materials in parts by weight: 70-85 parts of ethylene-vinyl acetate copolymer, 5-15 parts of aerogel, 4-12 parts of polyethylene, 4-10 parts of polyolefin elastomer, 2-8 parts of thermoplastic polyurethane, 0.5-6 parts of compatibilizer, 4-12 parts of ethylene propylene diene monomer (EPDM) rubber, 5-10 parts of foaming agent, and 0.5-6 parts of additives.

[0039] In some embodiments of the present invention, the foaming agent is at least one selected from azodicarbonamide, azobisisobutyronitrile, and 4,4'-oxobisbenzenesulfonylhydrazine. The foaming agent is preferably azodicarbonamide, which has the advantages of high gas evolution and controllable decomposition temperature.

[0040] In some embodiments of the present invention, the additive is at least one of zinc oxide, crosslinking agent and flow agent.

[0041] In some embodiments of the present invention, the additives include the following raw materials in parts by weight: 0.4-2 parts zinc oxide, 0.5-2 parts crosslinking agent, and 0.1-2 parts flow agent.

[0042] In some embodiments of the present invention, the crosslinking agent is at least one selected from dicumyl peroxide, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, bis-tert-butylperoxyisopropylbenzene, benzoyl peroxide, and di-tert-butyl peroxide.

[0043] In some embodiments of the present invention, the flow agent is at least one selected from fatty acids, fatty acid metal salts, fatty acid esters, fatty acid amides, hydrocarbon waxes, and metal soaps.

[0044] In some embodiments of the present invention, the flow agent is at least one selected from stearic acid, zinc stearate, and polyethylene wax. The flow agent can reduce melt viscosity, improve processing fluidity, and also serve as a release agent.

[0045] In some embodiments of the present invention, a method for preparing a lightweight thermal insulation composite material employs a supercritical foaming process, comprising the following steps: S1 Weigh out each ingredient according to the formula and mix them evenly; S2 adds the mixed material to the extruder for melt extrusion; S3 places the extrudate in a foaming device, fills it with nitrogen and carbon dioxide, and performs one foaming process. The foaming temperature is 75-85℃ and the foaming time is 90-150 minutes. S4 is depressurized to atmospheric pressure, then nitrogen and carbon dioxide are introduced for secondary foaming. The foaming temperature is 110-130℃ and the foaming time is 30-90 minutes. S5 cuts the obtained sheet into sections to obtain a lightweight thermal insulation composite sheet.

[0046] Furthermore, in step (1), the compatibilizer and aerogel are premixed in a high-speed mixer for 5-30 minutes; then, ethylene-vinyl acetate copolymer, polyethylene, polyolefin elastomer, and thermoplastic polyurethane are added and mixed evenly. The above premixing step allows the compatibilizer to preferentially act on the surface of the aerogel, forming an effective interfacial bonding layer. Then, through subsequent mixing, the aerogel is uniformly dispersed in the polymer matrix, thereby obtaining better mechanical properties and thermal insulation properties.

[0047] Furthermore, in step (2), the temperatures of each zone of the melt extrusion using a twin-screw extruder are: Zone 1 110-120℃; Zone 2 115-125℃; Zone 3 120-130℃; and the die temperature is 110-130℃.

[0048] In some embodiments of the present invention, a method for preparing a lightweight thermal insulation composite material includes the following steps: S1 Weigh out each ingredient according to the formula and mix them evenly; S2 The mixed materials are then subjected to intensive mixing at a temperature of 110-130℃ for 10-20 minutes. S3 refines the mixed material at a temperature of 110-130℃ for 5-15 minutes. S4 involves adding the refined material into an extruder for melt extrusion; S5 Place the extrudate in a foaming device and foam it once. The foaming temperature is 130-150℃ and the time is 20-40 minutes. S6 undergoes secondary foaming at a temperature of 160-170℃ for 30-90 minutes. S7 cuts the obtained sheet into sections to obtain a lightweight thermal insulation composite material.

[0049] Furthermore, in step (1), the compatibilizer and aerogel are premixed in a high-speed mixer for 5-30 minutes; then ethylene-vinyl acetate copolymer, polyethylene, polyolefin elastomer, thermoplastic polyurethane and EPDM rubber are added and mixed evenly, and then foaming agent and additives are added and mixed evenly.

[0050] Furthermore, in step S4, the temperatures of each zone of the melt extrusion using a twin-screw extruder are: zone 1 90-95℃, zone 2 92-100℃, zone 3 95-100℃, and the die temperature is 90-100℃.

[0051] Furthermore, after the supercritical foaming process or chemical foaming process is completed, the resulting sheet is slit. The slit thickness can be flexibly selected according to the actual application requirements, usually 0.5-5mm.

[0052] The lightweight thermal insulation composite material provided by this invention can be manufactured using either supercritical physical foaming or chemical foaming processes, depending on the different raw material combinations, exhibiting strong process adaptability. This lightweight thermal insulation composite material can be used in outdoor cold-weather clothing, cold chain transportation, industrial equipment, and pipeline insulation, among other fields.

[0053] Furthermore, after the supercritical foaming process or chemical foaming process of the lightweight thermal insulation composite material is completed, the lightweight thermal insulation composite material is punctured using a needle pressing device after it is made. The gap between the punctures is 0.5-1cm and the puncture diameter is 0.01-0.03mm. Example 1

[0054] In this embodiment, a lightweight thermal insulation composite material comprises the following raw materials in parts by weight: 80 parts of ethylene-vinyl acetate copolymer, 10 parts of silica aerogel, 8 parts of polyethylene, 7 parts of polyolefin elastomer, 4 parts of thermoplastic polyurethane, and 3 parts of compatibilizer.

[0055] In this embodiment, the ethylene-vinyl acetate copolymer is selected from Yanshan Petrochemical 14J4 ethylene-vinyl acetate copolymer. The polyethylene is selected from Yangzi BASF polyethylene 2426H. The polyolefin elastomer is selected from Dow ENGAGE 8150. The thermoplastic polyurethane is selected from Huntsman SMARTLITE® SCF 285. The silica aerogel is selected from Forsmann aerophobic gel powder with a particle size of 1-40 μm and a specific surface area of ​​600-800 m². 2 / g. The compatibilizer is a maleic anhydride-grafted polyolefin elastomer, specifically AMPLIFY GR216.

[0056] In this embodiment, a method for preparing a lightweight thermal insulation composite material employs a supercritical foaming process, comprising the following steps: S1. Premix the compatibilizer and aerogel in a high-speed mixer for 10 minutes; then add ethylene-vinyl acetate copolymer, polyethylene, polyolefin elastomer and thermoplastic polyurethane and mix evenly; S2 The mixture is added to a twin-screw extruder for melt extrusion. The temperatures of each zone of the twin-screw extruder are: Zone 1 115℃, Zone 2 120℃, Zone 3 125℃, and Die 120℃. S3 The extrudate is placed in an autoclave, and nitrogen and carbon dioxide are introduced until the pressure inside the autoclave reaches 20 MPa. Foaming is carried out once at 80°C for 120 min. The volume ratio of nitrogen to carbon dioxide is 1:1. S4 is depressurized to atmospheric pressure at a rate of 15 MPa / s, then nitrogen and carbon dioxide are introduced, and secondary foaming is carried out at 120°C for 60 minutes. S5 cuts the obtained foamed product into 2mm thick sheets to obtain a lightweight thermal insulation composite material. Example 2

[0057] In this embodiment, a lightweight thermal insulation composite material comprises the following raw materials in parts by weight: 80 parts of ethylene-vinyl acetate copolymer, 12 parts of aerogel, 10 parts of polyethylene, 6 parts of polyolefin elastomer, 4 parts of thermoplastic polyurethane, 4 parts of maleic anhydride-grafted polyolefin elastomer, and 0.5 parts of stearic acid.

[0058] In this embodiment, a method for preparing a lightweight thermal insulation composite material employs a supercritical foaming process, comprising the following steps: S1. The compatibilizer and aerogel are premixed in a high-speed mixer for 15 minutes; then ethylene-vinyl acetate copolymer, polyethylene, polyolefin elastomer and thermoplastic polyurethane are added and mixed evenly. S2 The mixture is added to a twin-screw extruder for melt extrusion. The temperatures of each zone of the twin-screw extruder are: Zone 1 110℃, Zone 2 115℃, Zone 3 120℃, and Die 115℃. S3 The extrudate is placed in an autoclave, and nitrogen and carbon dioxide are introduced until the pressure inside the autoclave reaches 20 MPa. Foaming is carried out once at 80°C for 120 min. The volume ratio of nitrogen to carbon dioxide is 1:1. S4 is depressurized to atmospheric pressure at a rate of 15 MPa / s, then nitrogen and carbon dioxide are introduced, and secondary foaming is carried out at 120°C for 60 minutes. S5 cuts the obtained foamed product into 1.5mm thick sheets to obtain a lightweight thermal insulation composite material.

[0059] The rest of this embodiment is the same as that in Embodiment 1. Example 3

[0060] In this embodiment, a lightweight thermal insulation composite material comprises the following raw materials in parts by weight: 82 parts of ethylene-vinyl acetate copolymer, 10 parts of silica aerogel, 9 parts of polyethylene, 8 parts of polyolefin elastomer, 4 parts of thermoplastic polyurethane, and 5 parts of compatibilizer.

[0061] In this embodiment, a method for preparing a lightweight thermal insulation composite material employs a supercritical foaming process, comprising the following steps: S1. Premix the compatibilizer and aerogel in a high-speed mixer for 10 minutes; then add ethylene-vinyl acetate copolymer, polyethylene, polyolefin elastomer and thermoplastic polyurethane and mix evenly; S2 The mixture is added to a twin-screw extruder for melt extrusion. The temperatures of each zone of the twin-screw extruder are: Zone 1 112℃, Zone 2 118℃, Zone 3 122℃, and Die 118℃. S3 The extrudate is placed in an autoclave, and nitrogen and carbon dioxide are introduced until the pressure inside the autoclave reaches 20 MPa. Foaming is carried out once at 80°C for 120 min. The volume ratio of nitrogen to carbon dioxide is 1:1. S4 is depressurized to atmospheric pressure at a rate of 10 MPa / s, then nitrogen and carbon dioxide are introduced, and secondary foaming is carried out at 120°C for 60 minutes. S5 cuts the obtained foamed product into 2.5mm thick sheets to obtain a lightweight thermal insulation composite material.

[0062] The rest of this embodiment is the same as that in Embodiment 1. Example 4

[0063] In this embodiment, a lightweight thermal insulation composite material comprises the following raw materials in parts by weight: 75 parts of ethylene-vinyl acetate copolymer, 10 parts of silica aerogel, 7 parts of polyethylene, 6 parts of polyolefin elastomer, 4 parts of thermoplastic polyurethane, 3 parts of compatibilizer, 6 parts of ethylene propylene diene monomer (EPDM) rubber, 1 part of zinc oxide, 10 parts of foaming agent, 1 part of crosslinking agent, and 0.5 parts of stearic acid.

[0064] In this embodiment, the ethylene-vinyl acetate copolymer is selected from Yanshan Petrochemical 14J4 ethylene-vinyl acetate copolymer. The polyethylene is selected from Yangzi BASF polyethylene 2426H. The polyolefin elastomer is selected from Dow ENGAGE 8200. The thermoplastic polyurethane is selected from Huntsman SMARTLITE® SCF 285. The ethylene propylene diene monomer (EPDM) rubber is selected from Taiwan Nanliang International EP-10. The silica aerogel is selected from Forsmann hydrophobic aerogel powder 1407014, with a pore size of 10-30 nm, a particle size of 2-40 μm, and a specific surface area of ​​600-800 m². 2 / g.

[0065] Furthermore, the foaming agent is azodicarbonamide; the crosslinking agent is dicumyl peroxide. In this embodiment, a method for preparing a lightweight thermal insulation composite material employs a chemical foaming process, including the following steps: S1. Premix the compatibilizer and aerogel in a high-speed mixer for 10 minutes; then add ethylene-vinyl acetate copolymer, polyethylene, polyolefin elastomer, thermoplastic polyurethane and EPDM rubber and mix evenly; then add foaming agent and additives and mix evenly. S2 involves internal mixing of the mixed materials at a temperature of 120°C for 15 minutes. S3 refines the internally mixed material on an open mill at a temperature of 120°C for 6 minutes. S4 The refined material is added to the twin-screw extruder for melt extrusion. The temperatures of each zone of the twin-screw extruder are: Zone 1 92℃, Zone 2 95℃, Zone 3 98℃, and Die 92℃. S5 The extrudate is placed in a foaming device for one foaming process at a foaming temperature of 140℃ for 30 minutes. S6 undergoes secondary foaming at a temperature of 165℃ for 60 minutes. S7 cuts the obtained foamed product into 2mm thick sheets to obtain a lightweight thermal insulation composite material. Example 5

[0066] In this embodiment, a lightweight thermal insulation composite material comprises the following raw materials in parts by weight: 80 parts of ethylene-vinyl acetate copolymer, 8 parts of aerogel, 5 parts of polyethylene, 5 parts of polyolefin elastomer, 4 parts of thermoplastic polyurethane, 4 parts of compatibilizer, 6 parts of ethylene propylene diene monomer (EPDM) rubber, 1 part of zinc oxide, 10 parts of foaming agent, 1 part of crosslinking agent, and 0.5 parts of flow agent.

[0067] Furthermore, the foaming agent is azodicarbonamide; the crosslinking agent is dicumyl peroxide; and the flow agent is stearic acid. In this embodiment, a method for preparing a lightweight thermal insulation composite material employs a chemical foaming process, comprising the following steps: S1. Premix the compatibilizer and aerogel in a high-speed mixer for 10 minutes; then add ethylene-vinyl acetate copolymer, polyethylene, polyolefin elastomer, thermoplastic polyurethane and EPDM rubber and mix evenly; then add foaming agent and additives and mix evenly. S2 involves internally mixing the mixed materials at a temperature of 125°C for 12 minutes. S3 refines the internally mixed material on an open mill at a temperature of 125°C for 5 minutes. S4 The refined material is added to the twin-screw extruder for melt extrusion. The temperatures of each zone of the twin-screw extruder are: Zone 1 90℃, Zone 2 95℃, Zone 3 100℃, and Die 90℃. S5 The extrudate is placed in a foaming device for one foaming process at a temperature of 135°C for 35 minutes. S6 undergoes secondary foaming at a temperature of 160℃ for 70 minutes. S7 cuts the obtained foamed product into 3mm thick sheets to obtain a lightweight thermal insulation composite material.

[0068] The rest of this embodiment is the same as that in Embodiment 4. Example 6

[0069] The lightweight thermal insulation composite material obtained in Example 1 was subjected to puncture treatment using a needle pressing device, with a puncture gap of 1 cm and a puncture diameter of 0.02 mm. Example 7

[0070] The lightweight thermal insulation composite material obtained in Example 4 was subjected to puncture treatment using a needle pressing device, with a puncture gap of 1 cm and a puncture diameter of 0.02 mm.

[0071] Comparative Example 1 The difference between this comparative example and Example 1 is that: the lightweight thermal insulation composite material of this comparative example includes the following raw materials in parts by weight: 80 parts of ethylene-vinyl acetate copolymer, 10 parts of silica aerogel, 8 parts of polyethylene, 7 parts of polyolefin elastomer, and 3 parts of maleic anhydride-grafted polyolefin elastomer compatibilizer.

[0072] Comparative Example 2 The difference between this comparative example and Example 1 is that: the lightweight thermal insulation composite material of this comparative example includes the following raw materials in parts by weight: 80 parts of ethylene-vinyl acetate copolymer, 10 parts of silica aerogel, 8 parts of polyethylene, 7 parts of polyolefin elastomer, and 4 parts of thermoplastic polyurethane.

[0073] Comparative Example 3 The difference between this comparative example and Example 4 is that this comparative example provides a lightweight thermal insulation composite material, comprising the following raw materials in parts by weight: 75 parts of ethylene-vinyl acetate copolymer, 10 parts of silica aerogel, 7 parts of polyethylene, 6 parts of polyolefin elastomer, 3 parts of compatibilizer, 6 parts of ethylene propylene diene monomer (EPDM) rubber, 1 part of zinc oxide, 10 parts of foaming agent, 1 part of crosslinking agent, and 0.5 parts of stearic acid.

[0074] Comparative Example 4 The difference between this comparative example and Example 4 is that this comparative example provides a lightweight thermal insulation composite material, comprising the following parts by weight of raw materials: 75 parts of ethylene-vinyl acetate copolymer, 10 parts of silica aerogel, 7 parts of polyethylene, 6 parts of polyolefin elastomer, 4 parts of thermoplastic polyurethane, 6 parts of ethylene propylene diene monomer (EPDM) rubber, 1 part of zinc oxide, 10 parts of foaming agent, 1 part of crosslinking agent, and 0.5 parts of stearic acid.

[0075] The performance of the lightweight thermal insulation composite materials prepared in Example 1 and Comparative Examples 1-2 was measured, and the test results are shown in Table 1 below: The performance of the lightweight thermal insulation composite materials prepared in Example 4 and Comparative Examples 3-4 was measured, and the test results are shown in Table 2 below: The thermal conductivity was determined according to GB / T 10295-2008 using a thermal conductivity meter at a test temperature of 25℃. The sample size was 200×200mm, and the thickness was the actual slice thickness. Density was determined according to GB / T 6343-2009. Springback was determined according to GB / T 6670-2008 using a falling ball spring tester with a steel ball diameter of 16mm and a drop height of 500mm. Multiple layers of sheet material were stacked to a total thickness of 50mm or more before testing. Tensile strength was tested according to GB / T 6344-2008 using a universal testing machine at a tensile speed of 500mm / min. Heat shrinkage was determined according to GB / T 8811-2008, by heating the sample in a 100℃ oven for 1 hour and measuring the shrinkage rate.

[0076] Comparing Example 1 with Comparative Examples 1-2, and Example 4 with Comparative Examples 3-4, it can be seen that the addition of thermoplastic polyurethane (TPU) can improve the resilience and cell wall toughness of the material, and the addition of compatibilizer can effectively solve the problem of aerogel agglomeration. The synergistic effect of the two gives the material excellent comprehensive performance.

[0077] The air permeability test results of the lightweight thermal insulation composite material in Example 6 are as follows: Figure 1 As shown. During the test, a lightweight thermal insulation composite sheet, after being perforated, was placed between a water cup and a gas cylinder. The water cup had a through hole at the bottom and was filled with liquid, while the gas cylinder was connected to a gas supply device. Figure 1 As shown, when the gas cylinder is not ventilated, the liquid in the cup cannot drip through the sheet, indicating that the sheet has good barrier properties when not under air pressure. When the gas cylinder is ventilated, gas can pass through the sheet into the bottom of the cup, generating bubbles in the water, indicating that the sheet has good air permeability under air pressure. Therefore, the lightweight thermal insulation composite material of this invention, after being perforated, maintains excellent thermal insulation performance while possessing good air permeability, achieving a balance between thermal insulation and breathable comfort. This helps expand its application in outdoor clothing, footwear, cushions, and other thermally insulated applications requiring breathability.

[0078] In summary, the lightweight thermal insulation composite material of the present invention, through the synergistic effect of aerogel, compatibilizer and multi-component polymer matrix composed of ethylene-vinyl acetate copolymer, polyethylene, polyolefin elastomer, thermoplastic polyurethane, etc., has the advantages of low thermal conductivity, low density and excellent resilience, tensile strength and dimensional stability.

[0079] The above embodiments are preferred implementations of the present invention. In addition, the present invention can be implemented in other ways. Any obvious substitutions without departing from the concept of the present invention are within the protection scope of the present invention.

Claims

1. A lightweight thermal insulation composite material, characterized in that: The raw materials include the following parts by weight: 70-85 parts of ethylene-vinyl acetate copolymer, 5-15 parts of aerogel, 4-12 parts of polyethylene, 4-10 parts of polyolefin elastomer, 2-8 parts of thermoplastic polyurethane, and 0.1-10 parts of compatibilizer.

2. The lightweight thermal insulation composite material according to claim 1, characterized in that: The aerogel is at least one of silica aerogel, alumina aerogel, carbon aerogel, and organic aerogel.

3. The lightweight thermal insulation composite material according to claim 1, characterized in that: The compatibilizer is at least one of maleic anhydride-grafted polyolefin elastomer, polysiloxane-modified polyurethane, and silane coupling agent.

4. The lightweight thermal insulation composite material according to claim 1, characterized in that: The lightweight thermal insulation composite material also includes the following raw materials in parts by weight: 4-12 parts of EPDM rubber, 5-10 parts of foaming agent, and 0.5-6 parts of additives.

5. The lightweight thermal insulation composite material according to claim 4, characterized in that: The foaming agent is at least one of azodicarbonamide, azobisisobutyronitrile, and 4,4'-oxobis(benzenesulfonyl)hydrazine.

6. The lightweight thermal insulation composite material according to claim 4, characterized in that: The additive is at least one of zinc oxide, crosslinking agent, and flow agent.

7. The lightweight thermal insulation composite material according to claim 6, characterized in that: The crosslinking agent is at least one selected from dicumyl peroxide, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, bis-tert-butylperoxyisopropylbenzene, benzoyl peroxide, and di-tert-butyl peroxide.

8. The lightweight thermal insulation composite material according to claim 6, characterized in that: The fluidizing agent is at least one of fatty acids, fatty acid metal salts, fatty acid esters, fatty acid amides, hydrocarbon waxes, and metal soaps.

9. A method for preparing a lightweight thermal insulation composite material as described in any one of claims 1-3, characterized in that: Includes the following steps: S1 Weigh out each ingredient according to the formula and mix them evenly; S2 adds the mixed material to the extruder for melt extrusion; S3 places the extrudate in a foaming device, fills it with nitrogen and carbon dioxide, and performs one foaming process. The foaming temperature is 75-85℃ and the foaming time is 90-150 minutes. S4 is depressurized to atmospheric pressure, then nitrogen and carbon dioxide are introduced for secondary foaming. The foaming temperature is 110-130℃ and the foaming time is 30-90 minutes. S5 cuts the obtained sheet into sections to obtain a lightweight thermal insulation composite sheet.

10. A method for preparing a lightweight thermal insulation composite material as described in any one of claims 4-8, characterized in that: Includes the following steps: S1 Weigh out each ingredient according to the formula and mix them evenly; S2 The mixed materials are then subjected to intensive mixing at a temperature of 110-130℃ for 10-20 minutes. S3 refines the mixed material at a temperature of 110-130℃ for 5-15 minutes. S4 involves adding the refined material into an extruder for melt extrusion; S5 Place the extrudate in a foaming device and foam it once. The foaming temperature is 130-150℃ and the time is 20-40 minutes. S6 undergoes secondary foaming at a temperature of 160-170℃ for 30-90 minutes. S7 cuts the obtained sheet into sections to obtain a lightweight thermal insulation composite material.

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