Vacuum thermal insulation board and preparation method therefor, and thermal insulation device

Abstract

Disclosed herein are a vacuum thermal insulation board and a preparation method therefor, and a thermal insulation device. The vacuum thermal insulation board comprises: a core material and a protective film covering the core material, wherein the core material is composed of a plurality of fiber cloths arranged in a stacked manner. The raw materials of the fiber cloths comprise organic fibers, wherein the organic fibers have a non-circular cross section. In addition, the areal density of the fiber cloths is 2 g / m2 to 150 g / m2.

Description

A vacuum insulation board and its preparation method, and a heat insulation device. Cross-reference to related applications

[0001] This disclosure claims priority to Chinese patent application No. 202411231544.9, filed on September 2, 2024, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This disclosure relates to the field of vacuum insulation materials technology, and in particular to a vacuum insulation board and its preparation method, as well as a heat insulation device. Background Technology

[0003] In insulation equipment requiring refrigeration or freezing functions, thermal insulation materials are typically used. Vacuum insulation panels, due to their excellent thermal insulation properties, demonstrate significant advantages in refrigeration and freezing applications. The structure of a vacuum insulation panel generally includes a core material, a getter / desiccant, and an outer protective film. Among these, the core material is the core component of the vacuum insulation panel, and its material, structure, and composition have a significant impact on the panel's thermal conductivity.

[0004] Currently, the core materials of commonly used vacuum insulation boards mainly include granular fumed silica and glass fiber, but these materials still face technical difficulties in further reducing their thermal conductivity. Summary of the Invention

[0005] This disclosure addresses, to some extent, the technical problem of high thermal conductivity in vacuum insulation panels during application in related technologies. To this end, this disclosure provides a vacuum insulation panel, its preparation method, and insulation equipment.

[0006] In a first aspect, this disclosure provides a vacuum insulation panel, the vacuum insulation panel comprising:

[0007] The core material comprises a core material and a protective film covering the core material; wherein the core material comprises multiple layers of fiber cloth, the raw material of the fiber cloth includes organic fibers, the organic fibers have a non-circular cross-section, and the areal density of the fiber cloth is 2 g / m³. 2 ~150g / m 2 .

[0008] As can be seen from this technical solution, this disclosure uses organic fibers with non-circular cross-sections as the core material of the vacuum insulation board. Due to their relatively complex molecular structure, organic fibers exhibit slow heat propagation and thus a low intrinsic thermal conductivity. Furthermore, the non-circular cross-section increases the physical spacing between organic fibers, reduces the contact area between them, and alters the heat conduction path, thereby reducing heat transfer efficiency and lowering the thermal conductivity. In addition, designing the areal density of the fiber cloth can help achieve a low thermal conductivity during film formation. Finally, through the synergistic effect of the low intrinsic thermal conductivity of the organic fibers, their non-circular cross-section, and the areal density of the fiber cloth, it is possible to construct a three-dimensional network structure supporting an infinitely large heat conduction path for the core material of the vacuum insulation board, thereby reducing the thermal conductivity of the vacuum insulation board during application.

[0009] In some embodiments, the shape of the non-circular cross section includes one of the following: triangle, trefoil, cross, T-shape, Y-shape, crescent shape, dumbbell shape, pentagram shape, fan shape, and pentagonal shape.

[0010] In some embodiments, the organic fiber includes at least one of the following: PET, polypropylene, polyethylene, polyester, polyamide, polyacrylonitrile, and polyvinyl alcohol.

[0011] In some embodiments, the organic fiber has a diameter of 0.5 μm to 50 μm.

[0012] In some embodiments, the diameter of the organic fiber is 3µm to 15µm.

[0013] In some embodiments, the organic fiber has a fiber length of 0.5 mm to 250 mm.

[0014] In some embodiments, the areal density is 5 g / m³. 2 ~100g / m 2 .

[0015] Secondly, this disclosure provides a method for preparing a vacuum insulation board according to any embodiment of the first aspect. The method includes: dispersing organic fibers in a liquid to obtain an organic fiber suspension; wet-forming the organic fiber suspension into a web and controlling the water content to obtain a wet fiber web; baking the wet fiber web to obtain a fiber cloth; stacking and heat-treating multiple sheets of the fiber cloth to obtain a core material; bagging the core material into a protective film to obtain a bagged board; and vacuum-sealing the bagged board until the vacuum degree of the bagged board reaches a set vacuum degree, thereby obtaining a vacuum insulation board.

[0016] In some embodiments, the weight of the organic fiber is 0.01% to 0.1% of the total weight of the organic fiber suspension.

[0017] In some embodiments, the dispersion method includes mechanical stirring and microwave heating.

[0018] In some embodiments, the water control time is 5 min to 30 min.

[0019] In some embodiments, the baking temperature is 100°C to 240°C.

[0020] In some implementations, the number of sheets is 100 to 500.

[0021] In some embodiments, the temperature of the heat treatment is 130°C to 200°C.

[0022] In some embodiments, the set vacuum level is 1.0 × 10⁻⁶. -4 Pa ~ 4.0 × 10 -3 Pa.

[0023] In some embodiments, the process parameters for the hot-press sealing include: voltage of 9V to 15V and time of 15s to 25s.

[0024] Thirdly, this disclosure provides a heat insulation device, which includes the vacuum insulation board described in any embodiment of the first aspect. Attached Figure Description

[0025] The accompanying drawings, which are incorporated in and form part of this disclosure, illustrate embodiments consistent with this disclosure and, together with the description, serve to explain the principles of this disclosure.

[0026] To more clearly illustrate the technical solutions in this disclosure or related technologies, the accompanying drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, those skilled in the art can obtain other drawings based on these drawings without any creative effort.

[0027] Figure 1 is a schematic diagram of the structure of a vacuum insulation board according to some embodiments of the present disclosure.

[0028] Figure 2 is a schematic flowchart of a method for preparing a vacuum insulation board according to some embodiments of the present disclosure.

[0029] The corresponding relationships between the reference numerals and components in the attached drawings are as follows: 1-Polyacrylonitrile core material; 2-Protective film; 3-Getter. Detailed Implementation

[0030] The technical solutions in this disclosure will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this disclosure, and not all embodiments. Based on the embodiments in this disclosure, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this disclosure.

[0031] Unless otherwise specified, the terminology used in this disclosure should be understood as having the meaning commonly used in the art. Therefore, unless otherwise defined, all technical and scientific terms used in this disclosure have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains. In the event of any conflict, this disclosure shall prevail. All raw materials, reagents, instruments, and equipment used in this disclosure are commercially available or can be prepared by existing methods.

[0032] Various embodiments of this disclosure may exist in the form of a range; it should be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as a hard limitation on the scope of this disclosure; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values ​​within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. Whenever a numerical range is indicated in this disclosure, it means including any referenced number (fraction or integer) within the indicated range.

[0033] In this disclosure, unless otherwise stated, directional terms such as “upper” and “lower” specifically refer to the drawing directions in the accompanying drawings. In the description of this disclosure, the terms “comprising,” “including,” etc., mean “including, but not limited to,” etc. Furthermore, the terms “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase “comprising…” does not exclude the presence of the same element in the process, method, article, or apparatus that includes said element. In this disclosure, relational terms such as “first” and “second” are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. In this disclosure, “and / or” describes the relationship between related objects, indicating that three relationships can exist; for example, A and / or B can represent: A alone, A and B simultaneously, or B alone. For a relationship of three or more related objects described by "and / or", it means that any one of the three related objects can exist alone, or at least two of them can exist simultaneously. For example, for A, and / or B, and / or C, it can mean that any one of A, B, and C exists alone, or any two of them exist simultaneously, or all three of them exist simultaneously. In this disclosure, "at least one" means one or more, and "more" means two or more. "At least one", "at least one of the following", or similar expressions refer to any combination of these items, including any combination of a single item or a plurality of items. For example, "at least one of a, b, or c", or "at least one of a, b, and c", can both mean: a, b, c, ab, i.e., a and b, ac, bc, or abc, where a, b, and c can be single or multiple.

[0034] Furthermore, reference numerals and / or reference letters may be repeated in different examples in this disclosure. Such repetition is for simplification and clarity purposes and does not in itself indicate a relationship between the various embodiments and / or settings discussed. In addition, this disclosure provides examples of various specific processes and materials, but those skilled in the art will recognize the application of other processes and / or the use of other materials.

[0035] Figure 1 is a schematic diagram of the structure of a vacuum insulation board according to some embodiments of the present disclosure.

[0036] Please refer to Figure 1. This disclosure provides a vacuum insulation board, which includes: a protective film 2; and a core material 1, wherein the protective film 2 covers the core material 1; wherein the core material 1 comprises multiple layers of fiber cloth, the raw material of the fiber cloth includes organic fibers, the organic fibers have a non-circular cross-section, and the areal density of the fiber cloth is 2 g / m³. 2 ~150g / m 2 .

[0037] As can be seen from this technical solution, this disclosure innovatively uses organic fibers with non-circular cross-sections as the core material of the vacuum insulation board. This choice is based on the unique physical properties of organic fibers: their complex molecular structure leads to a slower heat transfer rate within the fibers, thus giving organic fibers a lower intrinsic thermal conductivity.

[0038] The non-circular cross-section design not only increases the physical spacing between organic fibers and reduces the direct contact area between fibers, but also effectively alters the heat conduction path. These design considerations work together to reduce heat transfer efficiency, thereby significantly lowering the material's thermal conductivity.

[0039] Furthermore, through carefully designed fiber density, this approach ensures that the organic fibers maintain a low thermal conductivity during film formation. Optimizing this step is crucial for the performance of the final product.

[0040] This disclosure successfully constructs a three-dimensional network architecture that can infinitely increase the heat conduction path by leveraging the synergistic effect of the low intrinsic thermal conductivity of organic fibers, a non-circular cross-section design, and a reasonable fiber density. This architecture, as the core material of a vacuum insulation panel, significantly reduces the thermal conductivity of the panel during application, thereby improving its insulation performance.

[0041] For example, the areal density of the fiber cloth includes, but is not limited to, 2 g / m². 2 5g / m 2 10g / m 2 20g / m 2 30g / m 2 40g / m 2 50g / m 2 60g / m 2 70g / m 2 80g / m 2 90g / m 2 100g / m 2 120g / m 2 140g / m 2 150g / m 2 wait.

[0042] It should be noted that organic fibers have a low inherent thermal conductivity for the following reasons: (1) Thermal conductivity characteristics of organic materials: Due to the weak intermolecular forces, thermal vibrations are relatively difficult to transmit within organic materials, resulting in a generally low thermal conductivity. Compared with metallic materials, organic materials have poor thermal conductivity, and therefore organic fibers also have a low thermal conductivity. (2) Influence of fiber arrangement and structure: The thermal conductivity of organic fibers is affected by their arrangement direction and structure. When organic fibers are arranged parallel to the heat flow direction, the thermal conductivity is relatively enhanced; while when they are arranged perpendicular to the heat flow direction, the thermal conductivity is weakened. This is because vertically arranged organic fiber layers can more effectively trap still air, and still air is a poor conductor of heat, thus reducing the overall thermal conductivity.

[0043] The lower thermal conductivity of organic fibers with non-circular cross-sections is due to several factors, including: (1) Complex heat conduction paths: Compared to traditional circular cross-sections, organic fibers with non-circular cross-sections (such as triangular, trefoil, cross, T-shaped, Y-shaped, crescent-shaped, dumbbell-shaped, pentagonal, fan-shaped, and pentaforeform shapes) have more complex internal heat conduction paths. This complexity makes heat transfer in organic fibers more tortuous, thereby reducing the thermal conductivity and benefiting thermal insulation applications. (2) Influence of arrangement and gaps: The cross-sectional shape of non-circular cross-section fibers affects their arrangement and gap size in the organic fiber layer. When arranged parallel to the heat flow direction, the thermal conductivity is stronger; while when arranged perpendicular to the heat flow direction (i.e., parallel to the fiber layer), the thermal conductivity is weaker. Due to their complexity, non-circular cross-sections are more likely to form complex arrangements, which in turn reduces the thermal conductivity to some extent. In addition, the gaps between non-circular fibers may be relatively small, which also helps to reduce heat transfer.

[0044] In some embodiments, the fiber cloth has a three-dimensional network architecture.

[0045] The three-dimensional network architecture belongs to the microstructure of fiber fabric, mainly including the fiber arrangement, interlacing density, and porosity. These microstructural characteristics directly affect the thermal insulation, heat preservation, and breathability of the fiber fabric. In the fiber overlap structure of the fiber fabric disclosed in this invention, it is a disordered three-dimensional network shape under microscopic conditions. Heat is transferred within the overlapped fibers, and heat transfer between fibers occurs through contact points, which increases the difficulty of heat transfer. This, in turn, helps to reduce the thermal conductivity.

[0046] In some embodiments, the shape of the non-circular cross section includes one of the following: triangle, trefoil, cross, T-shape, Y-shape, crescent shape, dumbbell shape, pentagram shape, fan shape, and pentagonal shape.

[0047] It should be noted that the non-circular cross-sections listed in this embodiment are only some typical examples. Triangular, trefoil, pentagonal, and pentfolio shapes are classified as one type; cross-shaped, T-shaped, and Y-shaped shapes are classified as another type; and crescent-shaped, dumbbell-shaped, and fan-shaped shapes are classified as yet another type. Fibers with non-circular cross-sections are organic irregular fibers, which have better dispersion effects in water than conventional circular fibers, and the physical spacing between the fibers is larger.

[0048] In some embodiments, the organic fiber includes at least one of the following: PET, polypropylene, polyethylene, polyester, polyamide, polyacrylonitrile, and polyvinyl alcohol.

[0049] Organic materials have a lower intrinsic thermal conductivity compared to glass fiber or other inorganic non-metallic materials. Therefore, using organic fibers as the core material of vacuum insulation panels, thanks to the low thermal conductivity of organic fibers, can significantly reduce the thermal conductivity of the vacuum insulation panels in practical applications. Simultaneously, these organic fibers exhibit excellent chemical stability, effectively resisting the corrosive effects of the external environment and ensuring the long-term stability of the suspension.

[0050] It should be noted that PET, short for polyethylene terephthalate, is a thermoplastic polyester material. PET is a condensation polymer of terephthalic acid and ethylene glycol, with a highly symmetrical molecular structure and a certain degree of crystal orientation, thus exhibiting high film-forming and moldability. PET is a milky white or light yellow, highly crystalline polymer with a smooth and glossy surface. It possesses good creep resistance, fatigue resistance, abrasion resistance, and dimensional stability, as well as high hardness and good toughness. PET is resistant to oils, greases, dilute acids, dilute alkalis, and most solvents, but it is not resistant to hot water immersion or alkalis. Furthermore, PET has excellent weather resistance and chemical stability, and low water absorption.

[0051] Polypropylene, abbreviated as PP, is a polymer formed by the addition polymerization of propylene. It is a white, waxy material, transparent and lightweight. Its chemical formula is (C3H6)n, and its density is 0.89 g / cm³. 3 ~0.91g / cm 3 It is flammable, with a melting point of 164℃~170℃, softening at around 155℃, and an operating temperature range of -30℃~140℃. Below 80℃, it is resistant to corrosion from acids, alkalis, salt solutions, and many organic solvents, but decomposes under high temperatures and oxidation. Polypropylene is a high-performance thermoplastic synthetic resin, a colorless, semi-transparent, lightweight, general-purpose thermoplastic plastic with chemical resistance, heat resistance, electrical insulation, high mechanical strength, and good abrasion resistance.

[0052] Polyethylene (PE) is a thermoplastic resin produced by the polymerization of ethylene monomers. Industrially, it also includes copolymers of ethylene with small amounts of α-olefins. Polyethylene is odorless, non-toxic, and has a waxy feel. It possesses excellent low-temperature resistance (minimum operating temperature can reach -100℃ to -70℃). It has good chemical stability because the polymer molecules are linked by carbon-carbon single bonds, making it resistant to most acids and alkalis. It is insoluble in common solvents at room temperature, has low water absorption, and excellent electrical insulation properties.

[0053] Polyester is a general term for polymers obtained by polycondensation of polyols and polyacids, mainly referring to polyethylene terephthalate, abbreviated as PET. It has excellent physical and mechanical properties over a wide temperature range, with a service temperature up to 120℃. It has excellent electrical insulation properties, and its electrical properties are still good even at high temperatures and high frequencies. However, it has poor corona resistance, and good creep resistance, fatigue resistance, abrasion resistance, and dimensional stability.

[0054] Polyamide, abbreviated as PA, refers to polymers whose main chain segments contain polar amide groups (-CO-NH-). It can be obtained by ring-opening polymerization of amines or by condensation polymerization of diamines and diacids. Initially used as a raw material for manufacturing fibers, PA has become a widely used engineering plastic in industry due to its strength, wear resistance, self-lubrication, and wide operating temperature range.

[0055] Polyacrylonitrile (PCI), with the chemical formula (C3H3N)n, is a polymer compound obtained by free radical polymerization of acrylonitrile monomers. The acrylonitrile units in the macromolecular chain are linked in a link-to-end manner. PCI has advantages such as good weather resistance and resistance to sunlight; it retains 77% of its original strength after being placed outdoors for 18 months. It is also resistant to chemical reagents, especially inorganic acids, bleaching powder, hydrogen peroxide, and common organic reagents.

[0056] Polyvinyl alcohol, abbreviated as PVA, is a white, powdery, stable, non-toxic, water-soluble polymer produced by the alcoholysis and polymerization of vinyl acetate. It dissolves rapidly in water at room temperature to form a stable colloid, and water is an excellent solvent for PVA. PVA exhibits good film-forming properties, producing films with excellent adhesion, solvent resistance, abrasion resistance, tensile strength, and oxygen barrier properties. Possessing both hydrophilic and hydrophobic functional groups, PVA is an interfacially active substance, making it suitable as a protective colloid during polymer emulsification and suspension polymerization reactions.

[0057] In some embodiments, the organic fiber has a diameter of 0.5 μm to 50 μm.

[0058] Fiber diameter refers to the cross-sectional diameter of a single fiber. Limiting fiber diameter to 0.5µm to 50µm satisfies the requirements for film formation and low thermal conductivity, as well as properties such as softness, strength, elasticity, and hygroscopicity. This range ensures good contact between fibers while avoiding suspension flow problems caused by excessively large diameters. Fiber diameters exceeding 50µm can lead to poor film formation and shortened heat propagation paths, hindering the achievement of low thermal conductivity. Examples of organic fiber diameters include, but are not limited to, 0.5µm, 1µm, 5µm, 8µm, 10µm, 15µm, 20µm, 25µm, 28µm, 30µm, 35µm, 40µm, 45µm, and 50µm.

[0059] In some embodiments, the diameter of the organic fiber is 3µm to 15µm.

[0060] Limiting the diameter of organic fibers to 3µm to 15µm can better satisfy fiber film-forming properties and low thermal conductivity, as well as fiber softness, strength, elasticity and moisture absorption. At the same time, the fiber diameter within this range can ensure good contact between fibers and avoid suspension flow problems caused by excessive diameter.

[0061] In some embodiments, the organic fiber includes at least one of the following: filament fiber, short fiber, and ultra-short fiber; the fiber length of the organic fiber is 0.5 mm to 250 mm.

[0062] It should be noted that filament fiber, also known as continuous filament fiber, is a type of chemical fiber. A filament is a continuous, very long strand. Short fiber, also known as cut fiber, is a chemical fiber bundle that has been cut or broken into fibers equivalent to the lengths of various natural fibers. Miniature short fibers have a shorter cut length than conventional fibers and exhibit high dispersibility in a medium. The length of organic fibers is a crucial factor affecting their physical properties and performance; fibers of different lengths exhibit different behaviors and effects in suspensions. Long fibers typically have higher tensile strength and a better hand feel; medium-length fibers are generally soft, abrasion-resistant, and elastic; short fibers are typically soft and breathable; and miniature short fibers are generally soft and fluffy. In suspensions, fibers of different lengths can be mixed to adjust the physical properties and performance of the suspension.

[0063] In some embodiments, the short fiber has a fiber length of 25mm to 150mm, and the ultra-short fiber has a fiber length of 1mm to 12mm.

[0064] The short fibers are limited to a length of 25mm to 150mm, and the ultra-short fibers are limited to a length of 1mm to 12mm. This improves the dispersion of organic shaped fibers in the organic fiber suspension, thereby enhancing the film-forming properties of the organic fiber suspension and enabling it to achieve a low thermal conductivity during film formation. The short fibers, with a length of 25mm to 150mm, ensure good softness and breathability. The ultra-short fibers, with a length of 1mm to 12mm, provide ultimate softness and fluffiness. For example, the fiber lengths of the short fibers include, but are not limited to, 25mm, 30mm, 40mm, 50mm, 60mm, 70mm, 75mm, 80mm, 90mm, 100mm, 125mm, and 150mm; the fiber lengths of the ultra-short fibers include, but are not limited to, 1mm, 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, 11mm, and 12mm.

[0065] In some embodiments, the areal density is 5 g / m³. 2 ~100g / m 2 .

[0066] Areal density is the mass per unit area of ​​a fabric, expressed in meters. 2 The weight of the dried fabric is expressed in grams (g). Weight per unit area is an indicator of fabric quality and cost; a higher value indicates a denser and heavier knitted fabric, but also requires more raw materials, increasing fabric cost. Theoretically, the lower the areal density of the fiber fabric, the simpler the overlap between fibers and the fewer contact points between multiple fibers, which is beneficial for achieving ultra-low thermal conductivity. The areal density of the fiber fabric is limited to 5 g / m². 2 ~100g / m 2 On the one hand, it can meet the quality requirements of fiber cloth, thus making it suitable for preparing the inner core of vacuum insulation board; on the other hand, it can be more conducive to achieving ultra-low thermal conductivity.

[0067] Please refer to Figure 1. In some embodiments, the vacuum insulation panel further includes a getter 3.

[0068] Vacuum insulation panels, as a highly efficient and energy-saving thermal insulation material, possess excellent thermal insulation performance due to their unique structure and material composition. Besides the core material 1 and protective film 2, vacuum insulation panels also include a protective film 2 and a getter 3. These components work together to achieve their superior thermal insulation effect. The protective film 2 is the outer protective layer of the vacuum insulation panel, its main function being to isolate the external environment from the internal vacuum environment, preventing gas infiltration and heat transfer. Currently, the outer film of commonly used vacuum insulation panels mainly includes a gas barrier film. The getter 3 is an indispensable part of the vacuum insulation panel; its main function is to adsorb excess gas generated due to infiltration or material release, thereby maintaining the stability of the internal vacuum environment. The selection of the getter 3 is crucial to the performance of the vacuum insulation panel. In certain specific applications, additional desiccants may be used to reduce internal humidity and improve the performance of the vacuum insulation panel. In summary, vacuum insulation panels can be composed of a core material 1, a protective film 2, and a getter 3. These components work together to form the unique structure and excellent thermal insulation performance of vacuum insulation panels.

[0069] Figure 2 is a schematic flowchart of a method for preparing a vacuum insulation board according to some embodiments of the present disclosure.

[0070] Please refer to Figure 2. Based on a general inventive concept, this disclosure provides a method for preparing the vacuum insulation board described in any of the above embodiments, the method comprising:

[0071] S1. Disperse organic fibers in a liquid to obtain an organic fiber suspension; S2. Perform wet web formation and water control on the organic fiber suspension to obtain a wet fiber web; S3. Bake the wet fiber web to obtain a fiber cloth; S4. Stack and heat-treat multiple sheets of the fiber cloth to obtain a core material 1; S5. Pack the core material 1 into the protective film 2 to obtain a bagged plate; and S6. Vacuum the bagged plate, and when the vacuum degree of the bagged plate reaches the set vacuum degree, heat-seal the bagged plate to obtain a vacuum insulation plate.

[0072] In some embodiments, the weight of the organic fiber is 0.01% to 0.1% of the total weight of the organic fiber suspension.

[0073] This disclosure uses organic shaped fibers with non-circular cross-sections as the core material of vacuum insulation panels. By utilizing the unique interface morphology of the organic shaped fibers and limiting the weight ratio of the organic fibers in the total weight of the suspension, the dispersion effect of the organic shaped fibers in the organic fiber suspension and the physical spacing between the fibers are improved, and the contact area between the fibers is reduced. This, in turn, is beneficial to improving the film-forming properties of the organic fiber suspension and effectively blocking heat transfer efficiency. It also helps the organic fiber suspension achieve a low thermal conductivity during film formation. Simultaneously, the low intrinsic thermal conductivity of the organic shaped fibers facilitates the construction of a three-dimensional network structure supporting an infinitely large heat conduction path for the core material of the vacuum insulation panel, thereby reducing the thermal conductivity of the core material in application. The cross-section of the fibers in the organic fiber suspension can be any non-circular shape; these non-circular cross-sections help increase the contact area between the fibers, improving the stability and performance of the suspension. The weight percentage of organic fibers in a suspension is a key factor, directly affecting the suspension's physical properties and performance. Generally, the fiber weight percentage is 0.01% to 0.1%, and this range can be adjusted according to specific application requirements to achieve optimal thermal insulation, heat preservation, or strength effects. For example, the weight percentage of organic fibers relative to the total weight of the suspension may include, but is not limited to, 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, and 0.1%.

[0074] In some embodiments, the dispersion method includes mechanical stirring and microwave heating.

[0075] Dispersing organic fibers in liquids offers significant advantages for both the subsequent fabrication process and the fabric itself. Uniformly dispersed fibers are easier to handle and process in liquids, reducing fiber entanglement and knotting, thus improving the smoothness of the fibers during weaving or forming. Simultaneously, well-dispersed fibers can form a more uniform and denser fiber network during forming, contributing to improved fabric density and uniformity. Mechanical stirring, a form of intense turbulent motion, helps break down the mutual attraction and entanglement between fibers, allowing them to achieve better dispersion in the solution. Microwave heating utilizes microwave radiation for non-contact heating of substances, generating heat by inducing vibration and friction of polar molecules within the substance. In aqueous solutions of organic fibers, water molecules are the predominantly polar molecules; they rapidly heat up after absorbing microwave energy, further promoting fiber dispersion. Through the dispersion effect of mechanical stirring or microwave heating, organic fibers are more easily dispersed in aqueous solutions, reducing fiber tangling and increasing monofilament dispersion. This improvement has a positive impact on achieving low thermal conductivity in the subsequent film formation process of the organic fiber suspension.

[0076] It should be noted that wet web forming is a process in which fiber suspension is processed into a web in a wet state using specific equipment (such as a wet web forming machine). The fibers are dispersed in water containing chemical additives to form a suspension. The water in the suspension is filtered out using papermaking felts or screens, and the deposited fibers form a fiber web.

[0077] In some embodiments, the water control time is 5 min to 30 min.

[0078] In some embodiments, the baking temperature is 100°C to 240°C.

[0079] In some embodiments, the baking temperature is 140°C to 200°C.

[0080] Water control specifically involves removing excess liquid from the fiber web through methods such as squeezing and vacuum dewatering, thereby reducing energy consumption and time in the subsequent baking process. Water control reduces the moisture content in the fiber web while preventing excessive compression between fibers that could lead to structural damage, thus enabling the production of PET fiber fabrics with excellent performance and specific cross-sectional shapes. Furthermore, limiting the water control time to 5 to 30 minutes helps improve the efficiency of subsequent baking and dewatering. Examples of water control times include, but are not limited to, 5 minutes, 7 minutes, 9 minutes, 10 minutes, 12 minutes, 15 minutes, 18 minutes, 20 minutes, 22 minutes, 25 minutes, 28 minutes, and 30 minutes.

[0081] The baking process involves placing the dehydrated fiber web into a baking oven for heating. Hot air or infrared radiation is used to heat the fibers, causing them to bond stably and ultimately producing the fiber fabric. Baking ensures the bonding strength between fibers and the consistency of the product, resulting in fiber fabrics with excellent performance and specific cross-sectional shapes. The baking temperature is limited to 100℃–240℃ to improve the water removal efficiency and effect of the fiber fabric. Baking temperatures below 100℃ result in low water removal efficiency and poor water removal effect; baking temperatures above 240℃ can cause the organic fibers to melt and stick together. Examples of baking temperatures include, but are not limited to, 100℃, 120℃, 140℃, 150℃, 160℃, 170℃, 180℃, 200℃, 220℃, 230℃, and 240℃. Limiting the baking temperature to 140℃–200℃ improves the water removal efficiency and effect of the fiber fabric.

[0082] In some implementations, the number of sheets is 100 to 500.

[0083] By stacking multiple sheets of fiber cloth to form a multi-layered structure with a certain thickness and size, the thickness and density of the core material can be significantly increased, thereby improving its overall strength and stability. Simultaneously, the three-dimensional network structure of the multiple fiber cloths can interweave and fuse during the stacking process, forming a more complex and stable overall structure, which helps to improve the compressive strength, shear strength, and bending strength of the polyacrylonitrile core material. For example, the number of polyacrylonitrile fiber cloths stacked may include, but is not limited to, 100, 200, 300, 320, 340, 350, 370, 390, 400, 420, 440, 460, 480, and 500 sheets.

[0084] In some embodiments, the temperature of the heat treatment is 130°C to 200°C.

[0085] In some embodiments, the heat treatment temperature is 160°C to 180°C.

[0086] Heat treatment not only promotes cross-linking and fusion between fibers, enhancing the overall strength and stability of the core material, but also improves its thermal and chemical properties to a certain extent, thereby optimizing the internal structure and performance of the core material. Simultaneously, limiting the heat treatment temperature to 130℃~200℃ can accelerate the dehydration and drying effect of the core material, reducing its adsorption of moisture from the air. Heat treatment temperatures that are too low (below 130℃) result in low dehydration efficiency and poor dehydration effect; heat treatment temperatures that are too high (above 200℃) can easily cause the organic fibers to melt and stick together. For example, heat treatment temperatures include, but are not limited to, 130℃, 135℃, 140℃, 150℃, 155℃, 160℃, 165℃, 170℃, 175℃, 180℃, 185℃, 190℃, and 200℃. Limiting the heat treatment temperature to 160℃~180℃ can accelerate the dehydration and drying effect of the core material, reducing its adsorption of moisture from the air.

[0087] In some embodiments, the set vacuum level is 1.0 × 10⁻⁶. -4 Pa ~ 4.0 × 10 -3 Pa.

[0088] In the fabrication of vacuum insulation panels, vacuuming is a crucial step that directly affects the panel's insulation performance and lifespan. Limiting the vacuum level during vacuuming to 1.0 × 10⁻⁴ Pa to 4.0 × 10⁻³ Pa reduces heat loss through gas molecule conduction, thereby significantly improving the panel's insulation performance. For example, the vacuum level during vacuuming may include, but is not limited to, 1.0 × 10⁻⁴ Pa. -4 Pa, 1.2×10 -4 Pa, 1.5×10 -4Pa, 1.8 × 10 -4 Pa, 2.0×10 -4 Pa, 2.2×10 -4 Pa, 2.5 × 10 -4 Pa, 2.8 × 10 -4 Pa, 3.0 x 10 -4 Pa, 3.2 × 10 -4 Pa, 3.5 × 10 -4 Pa, 3.8 × 10 -4 Pa, 4.0 × 10 -4 Pa, 1.0 × 10 -3 Pa, 1.2×10 -3 Pa, 1.5×10 - 3 Pa, 1.8 × 10 -3 Pa, 2.0×10 -3 Pa, 2.2×10 -3 Pa, 2.5 × 10 -3 Pa, 2.8 × 10 -3 Pa, 3.0 × 10 -3 Pa, 3.2 × 10 -3 Pa, 3.5 × 10 -3 Pa, 3.8 × 10 -3 Pa, 4.0 × 10 -3 Pa, etc.

[0089] In some embodiments, the process parameters for the hot-press sealing include: voltage of 9V to 15V and time of 15s to 25s.

[0090] In the manufacturing process of vacuum insulation panels, hot-press sealing is a crucial step that decisively affects the product's sealing performance and final properties. By limiting the voltage to 9V–15V and the time to 15s–25s, hot-press sealing effectively improves the heat-fusion bonding effect of the inner layer of the membrane bag, thereby ensuring the sealing and insulation performance of the vacuum insulation panel. For example, the hot-press sealing voltage includes, but is not limited to, 9V, 9.5V, 10V, 10.5V, 11V, 11.5V, 12V, 12.5V, 13V, 13.5V, 14V, 14.5V, and 15V, and the hot-press sealing time includes, but is not limited to, 15s, 16s, 17s, 18s, 19s, 20s, 21s, 22s, 23s, 24s, and 25s.

[0091] Thirdly, this disclosure provides a heat insulation device comprising the vacuum insulation panel described in any of the above embodiments. The heat insulation device includes, but is not limited to, refrigerators, freezers, refrigerated trucks, and ice-freezing trucks.

[0092] Meanwhile, the applications of the vacuum insulation panels provided in this disclosure include, but are not limited to, thermal insulation equipment, and can also be used for building exterior wall insulation, RV insulation, spacecraft thermal insulation, etc.

[0093] The present disclosure is further illustrated below with specific embodiments and experimental data. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the disclosure. Experimental methods in the following embodiments, unless specific conditions are specified, are generally determined according to national standards. If no corresponding national standard exists, then generally accepted international standards, conventional conditions, or conditions recommended by the manufacturer are followed.

[0094] Example 1

[0095] This invention provides a vacuum insulation board, the preparation method of which includes:

[0096] S101. Disperse organic fibers in water to obtain an organic fiber suspension; wherein the organic fibers are triangular PET fibers with a diameter of 7 μm and a length of 5 mm, and the weight of the PET fibers is 0.05% of the total weight of the suspension; S102. Perform wet web forming on the organic fiber suspension and control the water for 5 minutes, then place it in an oven at 180℃ for baking for 2 hours, and demold to obtain a surface density of 15 g / m³. 2 S103. Multiple sheets of the fiber cloth are stacked and then placed in an oven and baked again at 200°C for 2 hours to obtain the core material.

[0097] S104. The core material bag is placed into the protective film to obtain a bagged plate; and S105. The bagged plate is placed in a vacuum sealing machine to perform vacuum treatment on the bagged plate until the vacuum degree of the bagged plate reaches 3.5×10. -3 At pressure Pa, the bagged plate is heat-sealed for 15 seconds at a heat-sealing voltage of 13V. Then, the getter shell is punctured by pressing to further reduce the internal pressure, thus obtaining a vacuum insulation plate.

[0098] Example 2

[0099] The difference between this embodiment and Embodiment 1 is that the organic fiber is a clover-shaped PET fiber with a diameter of 7µm and a length of 5mm.

[0100] Example 3

[0101] The difference between this embodiment and Embodiment 1 is that the organic fiber is a cross-shaped PET fiber with a diameter of 7µm and a length of 5mm.

[0102] Example 4

[0103] The difference between this embodiment and Embodiment 1 is that the organic fiber is a T-shaped PET fiber with a diameter of 7µm and a length of 5mm.

[0104] Example 5

[0105] The difference between this embodiment and Embodiment 1 is that the organic fiber is a Y-shaped PET fiber with a diameter of 7µm and a length of 5mm.

[0106] Example 6

[0107] The difference between this embodiment and Embodiment 1 is that the organic fiber is a crescent-shaped PET fiber with a diameter of 7µm and a length of 5mm.

[0108] Example 7

[0109] The difference between this embodiment and Embodiment 1 is that the organic fiber is a dumbbell-shaped PET fiber with a diameter of 7µm and a length of 5mm.

[0110] Example 8

[0111] The difference between this embodiment and Embodiment 1 is that the organic fiber is a five-pointed star-shaped PET fiber with a diameter of 7µm and a length of 5mm.

[0112] Example 9

[0113] The difference between this embodiment and Embodiment 1 is that the organic fiber is a fan-shaped PET fiber with a diameter of 7µm and a length of 5mm.

[0114] Example 10

[0115] The difference between this embodiment and Embodiment 1 is that the organic fiber is a five-lobed PET fiber with a diameter of 7µm and a length of 5mm.

[0116] Example 11

[0117] The difference between this embodiment and Embodiment 1 is that the organic fiber is a triangular polyamide fiber with a diameter of 7 μm and a length of 5 mm, and the weight of the polyamide fiber is 0.05% of the total weight of the suspension.

[0118] Example 12

[0119] The difference between this embodiment and Embodiment 1 is that the organic fiber is a cross-shaped polyamide fiber with a diameter of 7 μm and a length of 5 mm, and the weight of the polyamide fiber is 0.05% of the total weight of the suspension.

[0120] Example 13

[0121] The difference between this embodiment and Embodiment 1 is that the organic fiber is a triangular polyacrylonitrile fiber with a diameter of 7 μm and a length of 5 mm, and the weight of the polyacrylonitrile fiber is 0.05% of the total weight of the suspension.

[0122] Example 14

[0123] The difference between this embodiment and Embodiment 1 is that the organic fiber is a cross-shaped polyacrylonitrile fiber with a diameter of 7 μm and a length of 5 mm, and the weight of the polyacrylonitrile fiber is 0.05% of the total weight of the suspension.

[0124] Example 15

[0125] The difference between this embodiment and Embodiment 1 is that the weight of the PET fiber is 0.01% of the total weight of the suspension.

[0126] Example 16

[0127] The difference between this embodiment and Embodiment 1 is that the weight of the PET fiber is 0.1% of the total weight of the suspension.

[0128] Example 17

[0129] The difference between this embodiment and Embodiment 1 is that the diameter of the PET fiber is 3µm.

[0130] Example 18

[0131] The difference between this embodiment and Embodiment 1 is that the diameter of the PET fiber is 15µm.

[0132] Example 19

[0133] The difference between this embodiment and Embodiment 1 is that the fiber length of the PET fiber is 25mm.

[0134] Example 20

[0135] The difference between this embodiment and Embodiment 1 is that the fiber length of the PET fiber is 1 mm.

[0136] Example 21

[0137] The difference between this embodiment and Embodiment 1 is that the fiber length of the PET fiber is 50mm.

[0138] Example 22

[0139] The difference between this embodiment and Embodiment 1 is that the areal density of the fiber cloth is 5 g / m². 2 .

[0140] Example 23

[0141] The difference between this embodiment and Embodiment 1 is that the areal density of the fiber cloth is 100 g / m². 2 .

[0142] Example 24

[0143] The difference between this embodiment and Embodiment 1 is that the baking temperature for preparing the fiber cloth is 100℃.

[0144] Example 25

[0145] The difference between this embodiment and Embodiment 1 is that the baking temperature for preparing the fiber cloth is 240℃.

[0146] Comparative Example 1

[0147] This comparative example provides a vacuum insulation board, the preparation method of which includes:

[0148] S111. Disperse glass fibers in water to obtain a glass fiber suspension; wherein the glass fibers are circular glass fibers with a diameter of 7 μm and a length of 5 mm, and the weight of the glass fibers is 0.05% of the total weight of the suspension; S112. Perform wet web formation on the glass fiber suspension and drain water for 5 minutes, then place it in an oven at 180℃ for 2 hours, and demold to obtain a surface density of 25 g / m³. 2 S113. Stack multiple sheets of the glass fiber mat and bake them again at 200°C for 2 hours in an oven to obtain a core material; S114. Pack the core material into the protective film to obtain a bagged plate; and S115. Place the bagged plate in a vacuum sealing machine and vacuum the bagged plate until the vacuum degree of the bagged plate reaches 3.5 × 10⁻⁶. -3 At pressure Pa, the bagged plate is heat-sealed for 15 seconds at a heat-sealing voltage of 13V. Then, the getter shell is punctured by pressing to further reduce the internal pressure, thus obtaining a vacuum insulation plate.

[0149] Comparative Example 2

[0150] The difference between this embodiment and Embodiment 1 is that the organic fiber is a circular PET fiber with a diameter of 7µm and a length of 5mm.

[0151] Comparative Example 3

[0152] The difference between this comparative example and Example 1 is that the weight of the PET fiber is 2% of the total weight of the suspension.

[0153] Comparative Example 4

[0154] The difference between this comparative example and Example 1 is that the weight of the PET fiber is 0.001% of the total weight of the suspension.

[0155] Comparative Example 5

[0156] The difference between this comparative example and Example 1 is that the diameter of the organic fiber is 0.1 μm.

[0157] Comparative Example 6

[0158] The difference between this comparative example and Example 1 is that the diameter of the organic fiber is 60 μm.

[0159] Comparative Example 7

[0160] The difference between this comparative example and Example 1 is that the baking temperature for preparing the fiber cloth is 300°C.

[0161] Experimental Test

[0162] To better illustrate the thermal insulation performance of the vacuum insulation board provided in this disclosure, the thermal conductivity of the vacuum insulation boards obtained in Examples 1-25 and Comparative Examples 1-7 was tested, and the results are shown in Table 1.

[0163] Table 1. Thermal conductivity of the vacuum insulation boards obtained in Examples 1-25 and Comparative Examples 1-7

[0164] As shown in Table 1, compared to vacuum insulation boards with glass fiber and organic circular fiber cores, the vacuum insulation board with organic irregularly shaped fiber cores provided in this disclosure has a lower thermal conductivity and better insulation effect. Furthermore, as shown in Examples 1-25, the thermal conductivity of the vacuum insulation board with organic irregularly shaped fiber cores is strongly correlated with the fiber type and fiber cross-sectional morphology. The thermal conductivity of the vacuum insulation board with PET fiber cores is lower than that of polyamide and polyacrylonitrile, and the thermal conductivity of the vacuum insulation board with cross-shaped cross-section fiber cores is lower than that of other non-circular cross-sections. Therefore, in practical applications, vacuum insulation boards with cross-shaped cross-section PET fiber cores can be selectively prepared. Comparative Example 1 shows that the thermal conductivity of the vacuum insulation board prepared with organic fibers is significantly better than that of glass fiber. Comparative Example 2 shows that the thermal conductivity of the vacuum insulation board prepared with non-circular cross-section organic fibers is significantly better than that of circular cross-section organic fibers.

[0165] Furthermore, one or more technical solutions in this disclosure have at least the following technical effects or advantages:

[0166] In this disclosure, organic shaped fiber materials are used to replace fumed silica or glass fiber in the main material of vacuum insulation board core, overcoming the problems of cost, environmental harm, and inability to achieve ultra-low thermal conductivity.

[0167] In this disclosure, the efficient suspension and dispersion of organic irregularly shaped fibers creates conditions for the low basis weight of the fiber cloth after wet web formation, while the high rigidity of the organic irregularly shaped fiber material provides support for the three-dimensional network structure of the vacuum insulation board core material. Heat transfer takes place within the three-dimensional fiber network architecture, fully utilizing the low intrinsic thermal conductivity of the organic irregularly shaped fibers, their irregular cross-sections, and the infinitely large heat conduction path created by constructing a three-dimensional structure, ultimately producing a vacuum insulation board with ultra-low thermal conductivity.

[0168] In this disclosure, the initial thermal conductivity of the vacuum insulation board is less than 1.46 mW × (m K)⁻¹.

[0169] In this disclosure, the intrinsic thermal conductivity of glass fiber is much higher than that of organic polymer materials. Therefore, using organic fibers to replace glass fiber materials for the development of ultra-low thermal conductivity VIP boards has certain advantages. At the same time, the characteristic morphology of organic irregular fibers in the cross section greatly reduces the contact area between fibers, effectively blocking heat transfer efficiency and providing favorable conditions for ultra-low thermal conductivity.

[0170] In the description of this disclosure, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this disclosure. In this disclosure, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. In addition, those skilled in the art can combine and integrate the different embodiments or examples described in this disclosure.

Claims

1. A vacuum insulation board, comprising: Core material, and A protective film is provided, which covers the core material. The core material comprises multiple layers of fiber cloth, the raw material of which includes organic fibers with a non-circular cross-section, and the areal density of the fiber cloth is 2 g / m³. 2 ~150g / m 2 .

2. The vacuum insulation board according to claim 1, wherein, The fiber cloth has a three-dimensional network structure.

3. The vacuum insulation board according to claim 1 or 2, wherein, The shape of the non-circular cross section includes the following: triangle, trefoil, cross, T, Y, crescent, dumbbell, pentagon, fan, and pentafore.

4. The vacuum insulation board according to any one of claims 1 to 3, wherein, The organic fiber includes at least one of the following: PET, polypropylene, polyethylene, polyester, polyamide, polyacrylonitrile, and polyvinyl alcohol.

5. The vacuum insulation board according to any one of claims 1 to 4, wherein, The organic fiber has a diameter of 0.5 μm to 50 μm.

6. The vacuum insulation board according to any one of claims 1 to 5, wherein, The organic fiber has a diameter of 3µm to 15µm.

7. The vacuum insulation board according to any one of claims 1 to 6, wherein, The organic fiber has a fiber length of 0.5 mm to 250 mm.

8. The vacuum insulation board according to any one of claims 1 to 7, wherein, The areal density is 5 g / m³ 2 ~100g / m 2 .

9. A method for preparing a vacuum insulation board according to any one of claims 1 to 8, comprising: Organic fibers are dispersed in a liquid to obtain an organic fiber suspension; The organic fiber suspension is wet-laid and water is controlled to obtain a wet fiber web; The wet fiber web is baked to obtain a fiber cloth; Multiple sheets of the aforementioned fiber cloth are stacked and heat-treated to obtain the core material; The core material bag is placed into the protective film to obtain a bagged board; as well as The bagged plate is vacuumed, and when the vacuum degree of the bagged plate reaches the set vacuum degree, the bagged plate is heat-sealed to obtain a vacuum insulation plate.

10. The method according to claim 9, wherein, The weight of the organic fiber is 0.01% to 0.1% of the total weight of the organic fiber suspension.

11. The method according to claim 9 or 10, wherein, The dispersion methods include mechanical stirring and microwave heating.

12. The method according to any one of claims 9 to 11, wherein, The water control time is 5 min to 30 min; and / or the baking temperature is 100℃ to 240℃.

13. The method according to any one of claims 9 to 12, wherein, The number of images mentioned is between 100 and 500.

14. The method according to any one of claims 9 to 13, wherein, The heat treatment temperature is 130℃~200℃.

15. The method according to any one of claims 9 to 14, wherein, The set vacuum level is 1.0 × 10⁻⁶. -4 Pa ~ 4.0 × 10 -3 Pa.

16. The method according to any one of claims 9 to 15, wherein, The process parameters for hot-press sealing include: voltage of 9V to 15V and time of 15s to 25s.

17. A heat insulation device comprising the vacuum insulation board as described in any one of claims 1 to 8.

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