VIP heat insulation material for vacuum cup and preparation method and application thereof

Abstract

The invention relates to the technical field of thermal insulation materials, and discloses a VIP thermal insulation material, which comprises: a core material, which contains hydrophobic fumed silica aerogel and glass fibers; the barrier film is used for packaging the core material, and the barrier film is provided with at least three layers of structures; the getter is arranged in the barrier film; the BET specific surface area of the hydrophobic fumed silica aerogel is 500-900 m < 2 > / g, the pore volume is 2.0-4.0 cm < 3 > / g, the average particle size is 5-30 nm, and the content of the hydrophobic fumed silica aerogel in the core material is 60-85 wt%; and the fiber diameter of the glass fiber is 0.5-5 [mu] m. The arc-shaped preformed VIP plate is attached to the inner container, the cup opening structure is integrally formed through injection molding by means of the low-heat-conduction polymer, the cup bottom assists in heat insulation and is integrally vacuumized through the one-way exhaust valve, and the heat bridge effect is effectively blocked through the integration process.

Description

Technical Field

[0001] The present invention relates to the technical field of heat-insulating materials, in particular to a VIP heat-insulating material for a thermos cup, and a preparation method and application thereof. Background Art

[0002] VIP panels, or Vacuum Insulation Panels, are a new, highly efficient thermal insulation material. Formed by laminating a filler core with a high-barrier surface layer and then vacuuming the material, they fundamentally block heat transfer caused by air convection. Consequently, their thermal conductivity is significantly reduced, typically to less than 0.003w / mk. Furthermore, VIP panels contain no ozone-depleting substances (ODS), making them environmentally friendly and energy-efficient. Recognized as one of the most advanced and efficient thermal insulation materials available today, they offer broad application prospects in refrigerators, freezers, water heaters, and building energy efficiency.

[0003] However, existing VIP panels still face several challenges in practical application. First, despite their excellent initial insulation performance, the internal vacuum level slowly decreases over time. This is primarily due to the barrier film's limited gas permeability, allowing external water vapor and air molecules to gradually penetrate the VIP interior, causing a gradual increase in thermal conductivity and thus affecting its long-term insulation effectiveness. In some existing technologies, the core material lacks mechanical stability, potentially causing pulverization or structural collapse under prolonged vacuum and pressure conditions, further exacerbating the deterioration of thermal conductivity.

[0004] Secondly, traditional VIP panels are not well-suited for specific applications, such as curved products like thermoses. Typical VIP panels are flat, making it difficult to perfectly conform to curved surfaces. This can easily create gaps or stress at the joints, creating "thermal bridges" that become weak links in heat transfer, thereby weakening the overall insulation effect. Furthermore, the connection points of a thermos, such as the rim and bottom, are often areas of significant heat dissipation due to the direct connection between the inner and outer metal linings. This is known as the "thermal bridge effect," further reducing the overall performance of the thermos. Summary of the Invention

[0005] In response to the shortcomings of the existing technology, the present invention provides a VIP thermal insulation material for thermos cups, a preparation method and application thereof, which solves the problems of existing VIP thermal insulation materials in long-term vacuum stability, core material structure stability and significant thermal bridge effect in curved product applications.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solutions: VIP thermal insulation material, including: a core material comprising hydrophobic fumed silica aerogel and glass fiber; a barrier film, the barrier film encapsulating the core material, the barrier film having at least a three-layer structure; A getter is disposed within the barrier film.

[0007] By adopting the above technical solution, the core material achieves excellent thermal insulation performance through the composite structure of hydrophobic fumed silica aerogel and ultrafine glass fibers. The hydrophobic fumed silica aerogel, with its unique nanoporous structure, effectively inhibits convection and conduction heat transfer of gas molecules, while its hydrophobic properties prevent the degradation of thermal insulation performance caused by moisture adsorption. The ultrafine glass fibers serve as a supporting skeleton, giving the core material the necessary mechanical strength and structural stability, preventing it from collapsing or densifying during vacuum or pressure, thereby ensuring the long-term maintenance of the low thermal conductivity coefficient.

[0008] Regarding the barrier film, the present invention utilizes a high-barrier composite film with at least three layers to encapsulate the core material. In this multi-layer design, the middle layer of EVOH or nano-aluminized PET serves as the key barrier layer, significantly reducing the permeation rate of water vapor and non-condensable gases, thereby creating and maintaining a high vacuum environment within the VIP. The inner polyolefin layer ensures reliable heat sealing performance, while the outer BOPA or PET layer provides excellent mechanical strength and puncture resistance, fully protecting the internal vacuum structure. This composite film system significantly extends the vacuum maintenance life of the VIP and effectively prevents the degradation of thermal insulation performance caused by gas permeation.

[0009] As a getter, activated molecular sieves are strategically placed within the barrier film. Their mechanism is to efficiently absorb residual gases that aren't completely removed during the VIP's vacuuming process, as well as trace amounts of foreign gas molecules that slowly seep in during use. The getter's continuous action further stabilizes the vacuum level within the VIP, acting as a "vacuum maintenance station," significantly extending the VIP's effective service life and ensuring consistent thermal insulation performance in a variety of applications.

[0010] Preferably, the BET specific surface area of ​​the hydrophobic fumed silica aerogel is 500-900 m 2 / g, pore volume of 2.0-4.0cm 3 / g, an average particle size of 5-30nm, and its content in the core material is 60-85wt%.

[0011] Preferably, the glass fiber has a fiber diameter of 0.5-5 μm, a fiber length of 0.5-10 mm, and a content of the glass fiber in the core material of 15-40 wt %.

[0012] Preferably, the barrier film has at least three layers comprising an inner layer of polyolefin, a middle layer of EVOH or nano-aluminum-coated PET, and an outer layer of BOPA or PET, with a thickness ratio of (2-5):1:(1.5-3).

[0013] Preferably, the getter is an activated molecular sieve, and its content in the core material is 0.5-2.0 wt%.

[0014] A method for preparing a VIP thermal insulation material comprises the following steps: a. Mixing the hydrophobic fumed silica aerogel and ultrafine glass fiber and preforming the mixed core material; b. vacuum baking the preformed core material; c. placing the core material and the getter in a barrier film; d. vacuuming the barrier film; e. heat sealing the barrier film.

[0015] The above-mentioned technical solution begins with step a. mixing hydrophobic fumed silica aerogel and ultrafine glass fibers, and then preforming the resulting core material. This step forms the foundation for constructing the VIP core insulation structure. The hydrophobic fumed silica aerogel, with its nanoscale pores, significantly inhibits the free movement of gas molecules, thereby significantly reducing heat transfer by gas conduction and convection. Its hydrophobicity ensures that the insulation performance will not deteriorate due to moisture absorption during subsequent use. The ultrafine glass fibers provide structural support, forming a stable three-dimensional skeleton that prevents the aerogel from collapsing or pulverizing under vacuum or pressure, ensuring the integrity of the core material's internal pore structure. The mixing process aims to achieve uniform dispersion of the two materials, ensuring consistent insulation performance throughout the core material. Preforming imparts a preliminary shape and density to the core material, facilitating subsequent processing and packaging. It also helps reduce internal macroscopic pores, creating conditions for achieving higher vacuum levels.

[0016] Next comes step b. Vacuum baking the preformed core material; this is a key step in ensuring the long-term performance of the VIP. Core materials, especially those with porous structures, easily absorb moisture and other volatile gases from the air. If these adsorbed substances are not completely removed before packaging, they will gradually be released after the VIP is evacuated, resulting in a decrease in the vacuum level and a significant reduction in the insulation effect. Vacuum baking uses the synergistic effect of heating and a vacuum environment to accelerate and promote the desorption and discharge of moisture and gases adsorbed inside and on the surface of the core material. High temperature can provide sufficient energy to desorb molecules, while the vacuum environment can quickly extract these desorbed gases, ensuring that the core material has extremely low gas and moisture content when entering the packaging process, laying the foundation for the VIP's initial high vacuum level and long-term stability.

[0017] The subsequent steps are c. placing the core material and the getter inside the barrier film; and d. evacuating the barrier film; these two steps together build the vacuum core of the VIP. A getter (such as an activated molecular sieve) is placed next to the fully dried core material. The getter can absorb trace gases that may remain inside the VIP during the vacuum packaging process, as well as external gases that slowly penetrate the VIP throughout its life cycle. This means that even if there is a very small permeation of the barrier film, the getter can continue to "clean" these gases, thereby maintaining the ultra-low pressure environment inside the VIP. Subsequently, the barrier film is evacuated to expel most of the air from the film, creating a near-vacuum state. The degree of vacuum is the determining factor in the thermal insulation performance of the VIP. It greatly reduces gas conduction and convection, allowing heat to be transferred mainly through radiation and solid-phase conduction.

[0018] Finally, step e. heat-seals the barrier film. Heat sealing is the final sealing step in VIP preparation, and its quality directly determines the vacuum integrity and service life of the VIP. By applying heat and pressure to specific areas of the barrier film, the inner layer material (usually polyolefin) melts and fuses with each other to form a dense, continuous sealing line with sufficient mechanical strength. This heat-seal line effectively prevents external air and water vapor from re-entering the interior of the VIP, thereby locking the low-pressure environment created by the aforementioned vacuuming step. Precise control of the temperature, pressure and time of heat sealing is the key to ensuring the quality of heat sealing. It ensures that the molecules in the heat-sealed area can form a strong bond, preventing micro-leakage due to force or temperature changes during use, thereby ensuring that the VIP can perform its efficient thermal insulation properties in a long-term and stable manner.

[0019] Preferably, the heat sealing in step e adopts wide double-track heat sealing, the heat sealing temperature is 160-200° C., the pressure is 0.3-0.6 MPa, the holding time is 3-6 seconds, and the sealing width is 8-15 mm.

[0020] Preferably, the vacuum in step d is evacuated to 1×10 -2 -5×10 -1 Pa.

[0021] A VIP thermal insulation material is used in a thermos cup. The VIP thermal insulation material is placed in the interlayer between the inner and outer liner of the thermos cup. The VIP thermal insulation material is pre-formed in an arc shape and adheres to the outer wall of the inner liner of the thermos cup. The cup mouth and / or cup bottom of the thermos cup have a thermal bridge optimization structure.

[0022] The cup mouth thermal bridge optimization structure is an integrated injection molding structure of a low thermal conductivity polymer. The cup bottom thermal bridge optimization structure includes filling auxiliary insulation material and setting a one-way exhaust valve. The interlayer between the inner and outer liner of the thermos cup is vacuumed as a whole.

[0023] The present invention provides a VIP thermal insulation material for a thermos cup, and its preparation method and application. It has the following beneficial effects: 1. This invention utilizes a curved preformed VIP sheet to fit the inner liner, and utilizes a low-thermal-conductivity polymer for integrated injection molding of the cup mouth structure. This system incorporates auxiliary insulation at the cup bottom and a one-way exhaust valve for integrated vacuuming. This integrated process effectively eliminates the thermal bridge effect. Compared to existing VIP thermos, which commonly suffer from heat loss concentrated at the edges and complex integration, this invention significantly improves the overall thermal insulation performance and structural stability of the thermos.

[0024] 2. This invention utilizes a composite core material composed of hydrophobic fumed silica aerogel and ultrafine glass fibers, with an optimized component ratio. This solution significantly reduces the material's thermal conductivity and improves its insulation performance. Compared to existing single-component or conventional fiber-composite insulation core materials, this invention overcomes the material's susceptibility to moisture, insufficient structural stability, and limited thermal insulation performance.

[0025] 3. This invention incorporates three-layer co-extruded high-barrier composite film packaging technology, combined with a wide-width dual-track heat-sealing process and embedded getter strips. This innovation effectively extends the vacuum maintenance life of the VIP. Compared to existing common barrier films and traditional sealing methods, this invention overcomes the drawbacks of vacuum leakage and rapid thermal insulation degradation, ensuring the long-term and efficient operation of the VIP. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 Schematic diagram of the preparation process of the present invention. DETAILED DESCRIPTION

[0027] The following will clearly and completely describe the technical solution of the present invention in conjunction with the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0028] The embodiment of the present invention provides a VIP thermal insulation material, comprising: a core material, the core material comprising hydrophobic fumed silica aerogel and glass fiber; the hydrophobic fumed silica aerogel has a BET specific surface area of ​​500-900m 2 / g, pore volume of 2.0-4.0cm 3The glass fiber has an average particle size of 5-30 nm and a content of 60-85 wt % in the core material. The glass fiber has a fiber diameter of 0.5-5 μm, a fiber length of 0.5-10 mm, and a content of 15-40 wt % in the core material.

[0029] The barrier film encapsulates the core material, and the barrier film has at least a three-layer structure; the at least three-layer structure of the barrier film includes: an inner layer of polyolefin, a middle layer of EVOH or nano-aluminum-coated PET, and an outer layer of BOPA or PET, and the thickness ratio thereof is (2-5):1:(1.5-3).

[0030] The getter is placed in the barrier film and is an activated molecular sieve, with a content of 0.5-2.0 wt% in the core material.

[0031] Specifically, the VIP core material comprises hydrophobic fumed silica aerogel and glass fiber. The hydrophobic fumed silica aerogel has a BET specific surface area of ​​500-900 m 2 / g, pore volume of 2.0-4.0cm 3 / g, with an average particle size of 5-30nm, and its content in the core material is 60-85wt%. The uniqueness of this aerogel lies in its nanoscale pore structure, whose pore diameter is much smaller than the mean free path of air molecules, thereby effectively inhibiting the convective heat transfer and conductive heat transfer of gas molecules. The high specific surface area and pore volume further enhance this nanoscale confinement effect, ensuring an extremely low thermal conductivity. In addition, the hydrophobic treatment can prevent water molecules from condensing in the pores, avoiding the degradation of the insulation performance due to moisture, and ensuring the long-term stability of VIP in practical applications. The high content of aerogel ensures that the nanopore insulation mechanism occupies a dominant position in the overall core material.

[0032] At the same time, the glass fiber contained in the core material has a fiber diameter of 0.5-5μm, a fiber length of 0.5-10mm, and its content in the core material is 15-40wt%. The glass fiber plays a dual role here: first, it provides structural support. Since the aerogel itself has limited mechanical strength and is easily pulverized, the three-dimensional skeleton formed by the glass fiber can effectively prevent the core material from collapsing or densifying under vacuum and pressure environments, thereby maintaining its inherent pore structure. Secondly, the ultrafine glass fiber also plays an auxiliary insulation role. It can increase the curvature of the heat flow path and reduce solid-phase conduction. At the same time, its small diameter helps to reduce radiation heat transfer between fibers, thereby further reducing the overall thermal conductivity.

[0033] The right amount of glass fiber content ensures that it provides the necessary structural integrity without significantly negatively impacting the overall thermal insulation performance of the core. The key to maintaining the internal vacuum environment of the WIP lies in its barrier film.

[0034] Furthermore, the present invention utilizes a composite cation separator with at least three layers to encapsulate the core material. The specific structure includes an inner polyolefin layer, a middle EVOH or nano-aluminized PET layer, and an outer BOPA or PET layer. The thickness ratio of each layer is (2-5):1:(1.5-3). This multi-layer composite design leverages the synergistic effects of the different materials: the inner polyolefin layer provides excellent heat sealing and flexibility, ensuring a tight seal and cushioning protection for the core material; the middle EVOH or nano-aluminized PET layer serves as the core barrier layer. EVOH, through its molecular structure, effectively blocks gas permeation, while the nano-aluminized PET forms a dense physical barrier. Both layers provide excellent barrier properties against oxygen and water vapor, crucial for the long-term vacuum stability of VIP. The outer BOPA or PET layer primarily provides mechanical strength, abrasion resistance, and dimensional stability, protecting the fragile inner barrier layer from external damage. This specific thickness ratio is optimized to maximize the functionality of each layer, ensuring overall barrier performance while also balancing film flexibility, processability, and cost-effectiveness.

[0035] Please see the attached Figure 1 A method for preparing a VIP thermal insulation material comprises the following steps: a. mixing hydrophobic fumed silica aerogel and ultrafine glass fiber, and preforming the mixed core material; b. vacuum baking the preformed core material; c. Place the core material and getter inside the barrier film; d. Vacuum the barrier film; vacuum in step d to 1×10 -2 -5×10 -1 Pa.

[0036] e. Heat seal the barrier film. In step e, heat seal using wide double-track heat seals at a temperature of 160-200°C, a pressure of 0.3-0.6 MPa, a holding time of 3-6 seconds, and a sealing width of 8-15 mm.

[0037] Specifically, the first step is to prepare the core material, which includes fully mixing the hydrophobic fumed silica aerogel and ultrafine glass fiber, and preforming the mixed core material. The key to this step is the uniform dispersion and preliminary curing of the two core insulation components. The hydrophobic fumed silica aerogel provides a nanoscale pore structure to inhibit gas conduction and convection, while the ultrafine glass fiber acts as a skeleton to provide the necessary mechanical support for the fragile aerogel to prevent it from collapsing or pulverizing during subsequent processing and use. Through sufficient mixing, the uniform compounding of the two materials is ensured, so that the entire core material has consistent insulation performance and structural stability on a macro scale. The preforming process is to press the loose mixture into a preform with a preliminary shape and density by applying appropriate pressure, which is conducive to subsequent handling and precise packaging. At the same time, it can also reduce the internal large pores to a certain extent, creating conditions for achieving a higher vacuum degree.

[0038] Next, the preformed core material undergoes vacuum baking. This step aims to thoroughly remove residual moisture and adsorbed gases from within and on the surface of the core material. Moisture is a major factor affecting the thermal insulation performance of VIP. Its presence not only increases the core material's thermal conductivity but also forms water vapor in the vacuum environment, affecting the maintenance of vacuum. Vacuum baking accelerates the desorption of moisture and gases through heating, and utilizes the vacuum environment to promptly expel these desorbed substances, ensuring that the core material achieves extremely low moisture and gas content prior to packaging. This thorough drying and degassing process is essential for maintaining the VIP's initial high vacuum level and long-term performance stability.

[0039] The next step is to place the dried core material and getter inside the barrier film. The getter (typically an activated molecular sieve) is strategically placed next to the core material at this stage. Its function is to assist in the adsorption of residual gases during the subsequent vacuum pumping process and to continuously adsorb trace gases that penetrate the VIP over its lifetime, thereby extending the vacuum hold time. The core material and getter are precisely placed into a prefabricated barrier film bag in preparation for the final vacuum seal.

[0040] One of the key steps is to evacuate the barrier film until the internal pressure reaches 1×10 -2 -5×10 -1 Pa. Vacuuming is key to VIP's efficient insulation. By extracting the gas from within the barrier membrane, a near-vacuum environment is created, significantly reducing both gas conduction and convection heat transfer. Keeping the vacuum level at this low range means the number of gas molecules inside is extremely small, the mean free path is extremely large, and the probability of gas molecules colliding with the membrane wall is much higher than with each other, thus minimizing heat transfer. This precise vacuum control is the direct reason for VIP's exceptional thermal insulation performance.

[0041] Finally, the barrier film is heat-sealed. The present invention adopts wide-width dual-track heat-sealing technology. Heat sealing is a crucial sealing link in the VIP preparation process, which directly determines the vacuum integrity and long-term stability of the VIP. The use of "wide-width" heat sealing means that the width of the sealing area is large enough to provide a longer gas permeation path, thereby reducing the risk of leakage; "dual-track" heat sealing means that during the sealing process, the heat sealing strips heat and pressurize the film from both sides at the same time, ensuring uniform heating and melting of the sealing area, forming a more solid and defect-free sealing line. The controlled temperature, pressure and holding time ensure that the barrier film material (especially the inner layer of polyolefin) can fully melt and fuse with each other to form a dense and high-strength heat-sealing line, which effectively prevents external gas from penetrating, thereby locking the high vacuum inside the VIP.

[0042] A VIP thermal insulation material is used in a thermos cup. The VIP thermal insulation material is placed in the interlayer between the inner and outer liner of the thermos cup. The VIP thermal insulation material is pre-formed in an arc shape and adheres to the outer wall of the inner liner of the thermos cup. The cup mouth and / or cup bottom of the thermos cup have a thermal bridge optimization structure. The cup mouth thermal bridge optimization structure is an integrated injection molding structure of a low thermal conductivity polymer. The cup bottom thermal bridge optimization structure includes filling with auxiliary insulation material and setting a one-way exhaust valve. The interlayer between the inner and outer liner of the thermos cup is vacuumed as a whole.

[0043] Specifically, the key to this invention lies in placing VIP thermal insulation material between the inner and outer linings of a thermos. VIP material, thanks to its internal vacuum environment and nanoporous core structure, significantly inhibits heat conduction, convection, and radiation, making it one of the materials with the highest known thermal resistance. By placing it between the inner and outer linings of a thermos, it replaces traditional simple vacuum layers or conventional insulation materials, creating a strong thermal barrier between the inner and outer linings. This prevents heat from transferring through the inner and outer linings, thereby achieving superior heat preservation and cooling performance.

[0044] To better accommodate the curved surface of a thermos, this invention utilizes preformed curved VIP insulation material that fits perfectly to the outer wall of the thermos' liner. Traditional flat VIP materials struggle to perfectly conform to curved surfaces, easily creating gaps or stress that affect their insulation performance and service life. By pre-forming the VIP material into an arc that matches the curvature of the liner, a tight and seamless fit is ensured between the VIP and the liner, minimizing air gaps and preventing heat from convecting through these gaps. This fitting design not only optimizes the heat transfer path but also enhances the stability and shock resistance of the VIP's integration into the thermos.

[0045] Furthermore, the present invention incorporates a thermal bridge optimization design into the rim and / or bottom of the thermos cup. A thermal bridge is a localized area in an insulating structure where heat easily flows, typically at a material connection. In a thermos cup, the rim and bottom connect the inner and outer linings and serve as primary heat dissipation pathways. Special treatment of these areas aims to minimize heat loss through these pathways.

[0046] Specifically, the cup's thermal bridge optimization structure utilizes an integrated injection-molded structure made of a low-thermal-conductivity polymer. This means the cup's rim is no longer a simple metal connection, but instead is formed through an injection molding process using a polymer material with a thermal conductivity far lower than that of metal to form an integrated cup rim structure. This low-thermal-conductivity polymer effectively extends the heat transfer path from the inner liner to the outer liner and significantly reduces the heat transfer rate, thereby significantly reducing the thermal bridge effect at the cup's rim. The integrated injection molding also ensures structural strength and sealing.

[0047] The thermal bridge optimization structure at the bottom of the cup includes filling auxiliary insulation materials and setting a one-way exhaust valve. Filling the bottom area of ​​the cup with auxiliary insulation materials (such as polymer foam, aerogel felt, etc.) can further increase the thermal resistance of the bottom of the cup and make up for the thermal conductivity defects that may exist at the structural joints. The purpose of setting a one-way exhaust valve is to ensure the stability of the vacuum environment and the thoroughness of the exhaust process after the interlayer between the inner and outer liners of the thermos cup is vacuumed as a whole. The one-way exhaust valve allows gas to be discharged but prevents external gas from entering, which helps to vacuum more efficiently during the preparation process and deal with possible trace gas infiltration during the life of the product. By combining the thermal bridge optimization of the arc-shaped VIP's insulation body, cup mouth and cup bottom on the basis of the overall vacuuming of the thermos cup, the present invention constructs a multi-level, all-round insulation system to ensure that the thermos cup can maintain a long-term heat preservation or cooling effect under extreme conditions.

[0048] Example 1: Preparation of high-performance VIP thermal insulation material This example aims to demonstrate the preparation process of a VIP thermal insulation material with excellent thermal insulation performance, focusing on the optimized combination of core material, barrier film and getter.

[0049] 1. Core material preparation: Take 75wt% hydrophobic fumed silica aerogel (BET specific surface area 700m 2 / g, pore volume 3.0cm 3 / g, average particle size 15nm) and 25wt% ultrafine glass fibers (fiber diameter 2μm, fiber length 5mm). The two were mixed in a high-speed mixer at 1500rpm for 10 minutes to ensure uniform dispersion. The mixture was then placed in a mold and preformed at 0.5MPa pressure for 30 seconds to produce a pre-consolidated core board.

[0050] 2. Vacuum baking: Place the preformed core board in a vacuum oven. First, bake it at 120°C under normal pressure for 2 hours to remove most of the free water. Then, evacuate the oven to 500 Pa and continue baking at 150°C for 4 hours to completely remove adsorbed water and volatile substances.

[0051] 3. Packaging: Take a piece of appropriately sized barrier film (30μm inner polyethylene layer, 10μm middle EVOH layer, 20μm outer BOPA layer, with a thickness ratio of approximately 3:1:2) and carefully place the baked core material and 1wt% activated molecular sieve getter (relative to the weight of the core material) inside the barrier film. Ensure that the getter is evenly distributed around the edges of the core material.

[0052] 4. Vacuuming and Heat Sealing: The encapsulated barrier film is fed into the vacuum packaging machine. The cavity is first roughly evacuated, followed by fine evacuation to 1×10⁻¹ Pa. While maintaining this vacuum, wide-width dual-track heat sealing technology is used for sealing: the heat sealing temperature is set at 180°C, the heat sealing pressure is 0.4 MPa, the holding time is 4 seconds, and the sealing width is 10 mm. After sealing, the finished VIP board is removed.

[0053] Comparative Example 1: Preparation of VIP with conventional glass fiber core material: This comparative example is intended to be compared with Example 1, and to highlight the advantages brought about by the optimization of the core material components of the present invention.

[0054] 1. Preparation of core material: 100 wt% of conventional glass fiber (average fiber diameter 10 μm, length 20 mm) was taken and subjected to simple dispersion treatment and then preformed.

[0055] 2. Vacuum baking, packaging and vacuum heat sealing: the baking, packaging, vacuum and heat sealing steps are the same as those in Example 1.

[0056] Comparative Example 2: Preparation of VIP of Ordinary Barrier Film: This comparative example is intended to be compared with Example 1, and to highlight the advantages of the multi-layer high-barrier film of the present invention.

[0057] 1. Packaging: Take a piece of ordinary barrier film of appropriate size (only 50 μm polyethylene film) and carefully place the baked core material board and 1 wt% activated molecular sieve getter in it.

[0058] 2. Core material preparation, vacuum baking, and vacuum heat sealing: The core material preparation, vacuum baking, and vacuum heat sealing steps are the same as those in Example 1.

[0059] Comparative Example 3: Preparation of VIP without getter: This comparative example is intended to be compared with Example 1 to highlight the importance of the getter of the present invention.

[0060] 1. Packaging: Take a piece of barrier film of appropriate size (inner layer polyethylene 30μm, middle layer EVOH 10μm, outer layer BOPA 20μm), and place the baked core material board directly into the barrier film without adding any getter.

[0061] 2. Core material preparation, vacuum baking, vacuum heat sealing: The steps of core material preparation, vacuum baking and vacuum heat sealing are the same as those in Example 1.

[0062] Example 2: Integrated application of VIP thermal insulation materials in thermos cups: This example aims to demonstrate how to effectively integrate high-performance VIP materials into a thermos cup and optimize the thermal bridge structure between the cup mouth and the cup bottom to achieve improved overall thermal insulation performance.

[0063] 1. VIP plate preforming: According to the curvature of the liner of the thermos cup, the VIP plate prepared in Example 1 is preformed into an arc shape using a special hot pressing mold at 80°C, so that it fits perfectly with the outer wall of the liner and maintains a consistent curvature.

[0064] 2. Assemble the inner and outer liner and insert the VIP: Prepare the inner and outer liner of the thermos. Accurately position the pre-formed curved VIP panel on the outer wall of the inner liner, ensuring a tight fit. Then, install the inner liner and VIP panel into the outer liner.

[0065] 3. Optimizing thermal bridges at the cup opening: Using mold-integrated injection molding technology, a low-thermal-conductivity polymer (such as specialty nylon or PPO) is injected at the junction of the inner and outer liner openings, creating a seamless cup opening structure. The injection molding temperature is controlled at 220°C, the injection pressure is 80 MPa, and the pressure is maintained for 10 seconds. This structure eliminates direct thermal bridges between metals at the source.

[0066] 4. Optimize the thermal bridge at the bottom of the cup and vacuumize the entire layer: First, fill the bottom of the cup with a 5mm thick auxiliary insulation material (such as aerogel felt) in the bottom interlayer of the inner and outer liner. Then, install the vacuum interface with a one-way exhaust valve on the bottom of the cup. Place the entire thermos cup in the vacuum chamber, and use the vacuum pump to vacuum the interlayer between the inner and outer liner as a whole until the internal pressure of the interlayer reaches 5×10-2Pa. After the vacuum is completed, the one-way exhaust valve automatically closes and is sealed.

[0067] Comparative Example 4: Vacuuming the interlayer of a conventional thermos cup: 1. Inner and outer liner assembly and interlayer: This comparative example is intended to be compared with Example 2, focusing on the application of the VIP material of the present invention in the interlayer. Prepare the inner and outer liner of the thermos cup. No VIP material or auxiliary insulation material is placed between the inner and outer liner, and the cavity is directly left. 2. Treatment of the cup mouth and bottom and overall vacuuming: The cup mouth and bottom are connected by conventional metal methods (such as welding), and no special thermal bridge optimization is performed. Subsequently, the entire thermos cup is placed in a vacuum cavity, and the interlayer between the inner and outer liner is vacuumed as a whole, and the vacuum degree reaches 5×10 -2 Pa, and seal.

[0068] Comparative Example 5: Simple filling of flat VIP: This comparative example is intended to be compared with Example 2, and to highlight the advantages of the curved VIP preforming and lamination of the present invention.

[0069] 1. VIP material preparation: The flat VIP panel prepared in Example 1 was used without arc preforming.

[0070] 2. Assembly of inner and outer bladders and VIP implantation: After cutting the flat VIP board to the approximate size, insert it directly into the space between the inner and outer liner of the thermos. Because it is a flat board, there will be some gaps and non-fitting areas between it and the inner liner.

[0071] 3. Optimization of thermal bridge at the cup mouth, optimization of thermal bridge at the cup bottom and overall vacuuming: The cup mouth thermal bridge optimization, cup bottom thermal bridge optimization and overall vacuuming steps are the same as those in Example 2.

[0072] Comparative Example 6: VIP thermos cup without optimized thermal bridge at the cup mouth / bottom: This comparative example is intended to be compared with Example 2, emphasizing the importance of the optimized structure of the cup mouth / cup bottom thermal bridge of the present invention.

[0073] 1. VIP board preforming, inner and outer liner assembly and VIP implantation: The steps of VIP plate preforming, inner and outer liner assembly and VIP implantation are the same as those in Example 2.

[0074] 2. Treatment of cup rim and bottom and overall vacuuming: The rim and base of the cup are connected using conventional metal methods (such as welding), without any thermal bridge optimization methods such as low-thermal-conductivity polymer integrated injection molding, filling with auxiliary insulation materials, or installing a one-way exhaust valve. The entire thermos is then placed in a vacuum chamber, and the interlayer between the inner and outer linings is evacuated to a vacuum level of 5×10-2Pa and sealed.

[0075] Example 3: Preparation of VIP thermal insulation material with optimized core material ratio: This embodiment aims to further refine the influence of the core material ratio on the performance, and as a supplement to the first embodiment, embodies the refined control of the ratio.

[0076] Core material preparation: 80 wt% hydrophobic fumed silica aerogel (BET specific surface area 750 m 2 / g, pore volume 3.5cm 3 / g, average particle size 10nm) and 20wt% ultrafine glass fibers (fiber diameter 1μm, fiber length 3mm). The two were mixed at 1800rpm for 12 minutes and then preformed at 0.6MPa pressure for 40 seconds.

[0077] Vacuum baking: The preformed core material board is baked at 130℃ and normal pressure for 1.5 hours, then vacuumed to 300Pa and baked at 160℃ for 3.5 hours.

[0078] Packaging: Take a barrier film of appropriate size (inner layer polyethylene 25μm, middle layer nano-aluminum-coated PET 8μm, outer layer PET 18μm, thickness ratio of about 3.1:1:2.25), place the baked core material board and 1.5wt% activated molecular sieve getter in the barrier film.

[0079] Vacuuming and heat sealing: Vacuuming to 5×10-2 Pa. The heat sealing temperature is set to 170°C, the heat sealing pressure is 0.5 MPa, the holding time is 5 seconds, and the sealing width is 12 mm.

[0080] Comparative Example 7: Preparation of VIP with low aerogel content: This comparative example is intended to be compared with Example 3, focusing on the effect of aerogel content on thermal insulation performance.

[0081] Preparation of core material: 55 wt% of hydrophobic fumed silica aerogel (parameters are the same as those in Example 3) and 45 wt% of ultrafine glass fiber (parameters are the same as those in Example 3) are mixed and preformed.

[0082] Vacuum baking, packaging and vacuum heat sealing: the baking, packaging, vacuum and heat sealing steps are the same as those in Example 3.

[0083] Comparative Example 8: Preparation of VIP with high glass fiber content: This comparative example is intended to be compared with Example 3, focusing on the effect of excessive glass fiber content on thermal insulation performance.

[0084] Preparation of core material: 60 wt% of hydrophobic fumed silica aerogel (parameters are the same as those in Example 3) and 40 wt% of ultrafine glass fiber (parameters are the same as those in Example 3) are mixed and preformed.

[0085] Vacuum baking, packaging and vacuum heat sealing: the baking, packaging, vacuum and heat sealing steps are the same as those in Example 3.

[0086] Experiment: Evaluation of VIP material thermal conductivity and vacuum maintenance life: This experiment aims to further investigate the insulation performance of various VIP thermal insulation materials and their vacuum stability under simulated accelerated aging conditions. By precisely measuring initial thermal conductivity, long-term vacuum decay rate, and thermal conductivity after aging, we will comprehensively evaluate the technical superiority of the VIP materials proposed in this study, including component optimization, barrier film structure, and getter configuration.

[0087] Experimental instruments and consumables: Flat plate heat flow meter (accuracy ±3%, in line with ASTM C518 standard); Constant temperature and humidity chamber (temperature control accuracy ±1°C, humidity control accuracy ±3%RH); High-precision vacuum tester (e.g., equipped with a residual gas analysis module capable of measuring to 10-2Pa); VIP samples to be tested: Example 1: High-performance VIP thermal insulation material; Comparative Example 1: VIP with conventional glass fiber core material; Comparative Example 2: VIP of ordinary barrier film; Comparative Example 3: VIP without getter; Example 3: VIP thermal insulation material with optimized core material ratio; Comparative Example 7: VIP with low aerogel content; Comparative Example 8: VIP with high glass fiber content; Experimental steps: 1. Sample preparation: Ensure that all VIP samples to be tested are of uniform size (e.g., 300mm x 300mm), with a flat surface and no obvious defects. Record the detailed preparation information and number of each sample.

[0088] 2. Initial thermal conductivity measurement: Each VIP sample was placed one by one in the test area of ​​the flat plate heat flow meter.

[0089] The cold plate temperature of the heat flow meter was set to 10.0°C and the hot plate temperature was set to 30.0°C.

[0090] Start the equipment and wait for at least 2 hours to ensure that the test system reaches thermodynamic steady state.

[0091] Record the thermal conductivity reading of each sample at steady state. Repeat the measurement for each sample three times with an interval of 15 minutes between each measurement, and take the average value as its initial thermal conductivity.

[0092] 3. Accelerated aging environment settings: All VIP samples (including examples and comparative examples) were placed in a constant temperature and humidity chamber.

[0093] The temperature of the constant temperature and humidity chamber was set at 50° C. and the relative humidity was set at 90%.

[0094] Start the constant temperature and humidity chamber and begin the accelerated aging test.

[0095] 4. Regular monitoring of vacuum degree and thermal conductivity: All samples were removed from the constant temperature and humidity chamber on the 7th, 14th, 30th, 60th, 90th, and 180th day after the start of the accelerated aging test.

[0096] The samples were equilibrated at room temperature (23 ± 2°C) for 1 hour.

[0097] Using a high-precision vacuum tester, the vacuum level inside each sample is measured and recorded. For some VIP samples that may not have a reserved vacuum detection interface, non-contact measurement methods can be used, such as gas permeability analysis combined with initial inflation volume estimation.

[0098] At the key time points of 30 days, 90 days, and 180 days, the thermal conductivity of all samples was measured again using the same method as step 2.

[0099] After the measurement is completed, the sample is returned to the constant temperature and humidity chamber to continue aging.

[0100] Record all measurement data in detail, including sample number, test time, vacuum degree, thermal conductivity, etc.

[0101] Table 1: Changes in thermal conductivity and vacuum degree of VIP samples Through the analysis of the above experimental data, the VIP thermal insulation material of the present invention shows significant advantages in performance, which is derived from the inherent mechanism of its core technical solution. The excellent performance of Example 1 and Example 3 in terms of initial thermal conductivity directly confirms that the optimized core material ratio - that is, the composite structure of high-content nanoporous hydrophobic gas-phase silica aerogel and ultrafine glass fiber - can effectively inhibit gas convection and conduction. The extremely small pore size of the aerogel limits the mean free path of gas molecules, greatly reducing the gas heat transfer efficiency; at the same time, the glass fiber acts as a skeleton, providing the necessary structural support for the aerogel to prevent it from collapsing in a vacuum environment, thereby maintaining a stable pore structure inside the core material and avoiding the increase of thermal conductivity due to structural densification. This is in sharp contrast to Comparative Example 1 (conventional glass fiber core material), which lacks an effective nanoporous insulation mechanism, resulting in a high initial thermal conductivity.

[0102] In the accelerated aging test, the VIP samples of the embodiments of the present invention showed a slower vacuum decay rate and a more stable thermal conductivity, which highlights the importance of the synergistic effect of the barrier film and the getter. The three-layer high-barrier composite film used in the embodiment, by virtue of the excellent barrier properties of the middle layer EVOH or nano-aluminum-coated PET, significantly reduces the penetration rate of external water vapor and non-condensable gases into the interior of the VIP, thereby extending the vacuum retention life. In addition, the built-in activated molecular sieve getter continuously adsorbs residual and infiltrated trace gas molecules, further stabilizing the low-pressure environment inside the VIP, effectively addressing the inherent trace permeability of the barrier film, and ensuring the long-term and efficient thermal insulation performance of the VIP. This is in sharp contrast to Comparative Example 2 (ordinary barrier film) and Comparative Example 3 (no getter). The latter two have insufficient barrier properties or lack of gas adsorption capacity, resulting in a rapid deterioration of the vacuum degree and a significant decrease in thermal insulation performance.

[0103] Further analysis of the data of Example 3 and Comparative Examples 7 and 8 reveals the key influence of the precise proportion of the core material components. Example 3 achieves a further reduction in thermal conductivity and an improvement in long-term stability by adjusting the optimal ratio of aerogel to glass fiber. When the aerogel content is too low (such as Comparative Example 7), the nanopore insulation effect is not fully exerted, resulting in a high thermal conductivity; and when the glass fiber content is too high (such as Comparative Example 8), although structural support is provided, its own solid-phase conduction effect weakens the overall insulation effect to a certain extent. This refined component control enables the present invention to maximize the insulation potential of each component while maintaining structural integrity, thus standing out from similar products.

[0104] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. VIP thermal insulation material, characterized by: include: a core material comprising hydrophobic fumed silica aerogel and glass fiber; a barrier film, the barrier film encapsulating the core material, the barrier film having at least a three-layer structure; A getter is disposed within the barrier film.

2. The VIP thermal insulation material according to claim 1, characterized in that: The BET specific surface area of ​​the hydrophobic fumed silica aerogel is 500-900 m 2 / g, pore volume of 2.0-4.0cm 3 / g, an average particle size of 5-30nm, and its content in the core material is 60-85wt%.

3. The VIP thermal insulation material according to claim 1, characterized in that: The glass fiber has a fiber diameter of 0.5-5 μm, a fiber length of 0.5-10 mm, and a content of 15-40 wt % in the core material.

4. The VIP thermal insulation material according to claim 1, characterized in that: The barrier film has at least three layers including an inner layer of polyolefin, a middle layer of EVOH or nano-aluminum-coated PET, and an outer layer of BOPA or PET, with a thickness ratio of (2-5):1:(1.5-3).

5. The VIP thermal insulation material according to claim 1, characterized in that: The getter is an activated molecular sieve, and its content in the core material is 0.5-2.0 wt %.

6. A method for preparing a VIP thermal insulation material, the VIP thermal insulation material according to any one of claims 1 to 5, characterized in that: The following steps are involved: a. Mixing the hydrophobic fumed silica aerogel and ultrafine glass fiber and preforming the mixed core material; b. vacuum baking the preformed core material; c. placing the core material and the getter in a barrier film; d. vacuuming the barrier film; e. heat sealing the barrier film.

7. The method for preparing a VIP thermal insulation material according to claim 6, characterized in that: The heat sealing in step e adopts wide double-track heat sealing, the heat sealing temperature is 160-200° C., the pressure is 0.3-0.6 MPa, the holding time is 3-6 seconds, and the sealing width is 8-15 mm.

8. The method for preparing a VIP thermal insulation material according to claim 6, characterized in that: The vacuum in step d is evacuated to 1×10 -2 -5×10 -1 Pa.

9. Application of a VIP thermal insulation material in a thermos cup, the VIP thermal insulation material according to any one of claims 1 to 5, characterized in that: The VIP thermal insulation material is placed in the interlayer between the inner and outer liner of the thermos cup. The VIP thermal insulation material is pre-formed in an arc shape and fits onto the outer wall of the inner liner of the thermos cup. The cup mouth and / or cup bottom of the thermos cup have a thermal bridge optimization structure.

10. The use of the VIP thermal insulation material in a thermos cup according to claim 9 is characterized in that: The cup mouth thermal bridge optimization structure is an integrated injection molding structure of a low thermal conductivity polymer. The cup bottom thermal bridge optimization structure includes filling auxiliary insulation material and setting a one-way exhaust valve. The interlayer between the inner and outer liner of the thermos cup is vacuumed as a whole.

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