A heat insulating plate for the inner wall of a kiln and a method for manufacturing the same

Abstract

This invention discloses an insulation board for the inner wall of a kiln and its preparation method. The process involves hot-pressing foamed sheets into a box-shaped structure with a bottom and side walls. After a permeability treatment, micropores and an inner wall filter layer are formed, giving it air permeability and leak-proof properties. The foamed sheets serve as a molding mold and permanent protective layer. Insulating powder is filled into the cavity, and the entire board is then placed in a vacuum bag for vacuum sealing, compacting the powder into a core. Simultaneously, the foamed sheets are tightly adhered to the bottom and sides of the core, forming an integrated protection. The resulting insulation board includes a core and an elastic buffer layer covering its bottom and sides. The inner wall of the buffer layer is composite with a filter layer, and the outer wall is composite with a rigid support layer with ventilation holes. This invention achieves a one-time molding and gapless bonding of the buffer layer and core, resolving the contradiction between the impermeability of foamed materials and the vacuum process, significantly improving puncture resistance during construction, and is simple and low-cost.

Description

Technical Field

[0001] This invention relates to the field of thermal insulation material preparation technology, and more specifically, to a thermal insulation board for the inner wall of a kiln and its preparation method. Background Technology

[0002] The inner walls of kilns are constantly exposed to high temperatures of several hundred degrees Celsius. To reduce heat loss and ensure the kiln's thermal efficiency, insulation boards are typically laid on the inner walls. These insulation boards are mostly made of porous materials (such as calcium silicate and ceramic fibers), which are prone to structural damage and a sharp decline in insulation performance after absorbing water. Therefore, it is crucial to strictly prevent cement slurry from seeping into the insulation boards during construction. Current technology commonly uses a fiberglass-aluminum foil composite film to vacuum-seal the insulation boards. Utilizing the excellent water resistance and mechanical strength of aluminum foil, a temporary waterproof barrier is formed during the construction phase. Once the kiln is ignited and operational, although the high temperatures will cause the aluminum foil layer to oxidize and become ineffective, the concrete has already solidified, and the insulation boards no longer require waterproofing.

[0003] However, the actual construction environment is extremely complex. Concrete often contains sharp aggregates such as stones and sand of varying sizes, which frequently impact and scratch the surface of the insulation board during pouring and vibration. Conventional fiberglass vacuum bags are only about 0.1mm thick, making them easily punctured or scratched by the concentrated stress from the sharp edges of the aggregates. In addition, bending and dropping during transportation and handling can cause micro-cracks on the aluminum foil that are difficult to detect with the naked eye. Once the aluminum foil is damaged, cement slurry will quickly seep into the interior of the insulation board through the crack, causing the core to pulverize and peel off. In severe cases, it can even cause the inner wall of the kiln to bulge and fall off, requiring production shutdown for repairs and resulting in huge economic losses.

[0004] To address the aforementioned issues, a common improvement measure is to attach an additional layer of non-woven fabric or foam sheet to the surface of the vacuum bag as a cushioning and protective layer. However, this approach has the following inherent drawbacks:

[0005] First, the buffer layer is separate from the insulation core. The buffer layer is only attached to the surface of the vacuum bag by adhesives such as double-sided tape. During handling and stacking, the edges are very easy to lift up, and it is even more likely to fall off when washed by concrete slurry during pouring, resulting in poor protection reliability.

[0006] Second, the protection is incomplete. Traditional external buffer layers typically only cover the bottom surface of the insulation board, while the sides are completely exposed. In actual construction, aggregates can directly impact the vacuum bag from the sides, resulting in a very high rate of sidewall punctures, making it a "weak link" in the waterproofing system.

[0007] Third, there is poor process compatibility. Commonly used cushioning materials such as polyethylene and EVA foam sheets have a closed-cell structure and are not breathable. If they are pre-attached before vacuum sealing, it will severely hinder the air from escaping from the bag, resulting in prolonged vacuuming time, insufficient vacuum, or even sealing failure. If they are attached separately after vacuum sealing, an additional independent process is required, which reduces production efficiency and increases manufacturing costs.

[0008] Fourth, size adaptability is limited. Flat buffer sheets are difficult to perfectly fit the edges, corners, and other irregular parts of the insulation board, leaving blind spots for protection during construction.

[0009] Therefore, developing a heat insulation board that can achieve integrated molding of the heat insulation board and the buffer layer, provide comprehensive protection for the bottom and sides, and is fully compatible with the existing heat insulation board manufacturing process and product structure of vacuum packaging production lines has become a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0010] To overcome the above-mentioned defects of the prior art, embodiments of the present invention provide an insulation board for the inner wall of a kiln and a method for preparing the same.

[0011] To achieve the above objectives, the present invention provides a method for preparing an insulation board for the inner wall of a kiln, the innovation of which lies in the following steps:

[0012] Elastic foamed sheets are used and, before the air permeability treatment, they are made into a box-shaped structure with a bottom wall, side walls and a cavity formed by the bottom wall and side walls through a hot pressing process. The foamed sheets have an inner wall surface surrounding the cavity.

[0013] The foamed sheet is treated to make it breathable, so that gas can pass through but solid insulation material powder cannot.

[0014] The permeable foamed sheet is used as a molding mold and a permanent protective layer, and is placed on the worktable of the vacuum sealing equipment.

[0015] Fill the cavity of the foamed sheet with insulating material powder;

[0016] The foamed sheet, along with the internal insulation material powder, is encapsulated in a vacuum bag. The vacuum bag is then vacuumed and heat-sealed, causing the insulation material powder to form a dense powder blank that conforms to the shape of the containment cavity under vacuum. At the same time, the foamed sheet is tightly attached to the bottom and sides of the blank, forming an integrated protective structure.

[0017] Furthermore, the permeability treatment includes: forming multiple micropores penetrating the thickness direction on the surface of the foamed sheet, wherein the micropores are formed by at least one of mechanical needle punching, laser drilling or high-pressure hydroentangling.

[0018] Furthermore, the breathability treatment also includes: applying a breathable filter layer that does not allow solid powder to pass through to the inner surface of the foamed sheet.

[0019] Furthermore, the present invention also includes a rigidity enhancement treatment on the foamed sheet: a rigid support layer is laminated on the outer surface of the foamed sheet, the rigid support layer having a porous and breathable structure, or having ventilation holes on it corresponding to the micropore positions of the foamed sheet.

[0020] Furthermore, before placing the foamed sheet into the vacuum sealing equipment, a release layer is provided on the outer surface of the foamed sheet or the inner surface of the vacuum bag. The release layer is a release film or a low surface energy coating.

[0021] Furthermore, the vacuum sealing equipment has a vacuum chamber, a worktable is set inside the vacuum chamber, and a vacuum bag is placed on the worktable and is located inside the vacuum chamber for vacuuming.

[0022] Vacuum sealing equipment also has a heat sealing strip, which is set inside the vacuum chamber. The opening of the vacuum bag is placed on the heat sealing strip for heat sealing.

[0023] The present invention provides an insulation board for the inner wall of a kiln prepared by the above-described preparation method.

[0024] Furthermore, the insulation board has an elastic buffer layer, which is made of breathable foamed sheet material. The elastic buffer layer has a bottom wall and side walls, forming an integrated box-shaped structure, and covers the bottom and four sides of the insulation board core, and is tightly bonded to the insulation board core without gaps.

[0025] The elastic buffer layer is provided with breathable micropores that penetrate its thickness. Its inner wall surface is composited with a breathable and leak-proof filter layer, and its outer surface is composited with a rigid support layer. The rigid support layer is provided with vent holes corresponding to the positions of the breathable micropores.

[0026] The filter layer is at least one of non-woven fabric, microporous polytetrafluoroethylene membrane or glass fiber filter paper;

[0027] The rigid support layer is at least one of polyethylene terephthalate sheet, polypropylene sheet, or metal foil.

[0028] Furthermore, the elastic buffer layer is a one-piece thermoformed box-shaped structure with a continuous, seamless bottom wall and four side walls, providing comprehensive protection for the bottom and four sides of the insulation board core.

[0029] Furthermore, the material of the elastic buffer layer is at least one of polyethylene foam sheet, ethylene-vinyl acetate copolymer foam sheet or polypropylene foam sheet, and its thickness is 0.5-2.0 mm.

[0030] The technical effects and advantages of this invention are as follows:

[0031] 1. Achieving integrated molding and comprehensive protection of the buffer layer and insulation core: This invention pre-presses foamed sheets into a box-shaped structure with a bottom and side walls. This box-shaped structure simultaneously serves as a molding mold for the insulation powder and a permanent protective layer. During vacuum sealing, negative pressure causes the foamed sheets to shrink uniformly inward, tightly adhering to the insulation powder without gaps. After the powder is compacted, the foamed sheets are permanently attached to the core surface, forming an integrated protective structure. This structure completely solves the problem of warping and detachment of traditional external buffer layers. Simultaneously, the box-shaped structure naturally covers the bottom and four sides of the core, with only the top open, achieving five-sided surround physical protection. This overcomes the fundamental defect of existing technologies that only protect the bottom and lack side wall protection, significantly improving the ability to resist puncture by concrete aggregate during construction.

[0032] 2. Perfect compatibility with existing vacuum sealing processes through a breathable design: This invention addresses the airtightness caused by the closed-cell structure of foamed sheets by combining penetrating micropores with an inner wall filter layer, or by aligning the penetrating micropores with the ventilation holes of the rigid support layer, enabling the foamed sheet to have directional air permeability. During vacuuming, air within the containment cavity can be quickly discharged along the micropore-ventilation path, while the insulating powder is effectively blocked by the filter layer, preventing leakage and contamination. This design requires no modification to existing vacuum sealing equipment and can directly utilize standard vacuuming and heat-sealing parameters, resulting in a simple and efficient process that combines low cost and high reliability. Attached Figure Description

[0033] Figure 1 Example 1: A three-dimensional schematic diagram of the foamed sheet being hot-pressed into a box-shaped structure.

[0034] Figure 2 : A cross-sectional view of the structure of the foamed sheet after air permeability treatment and rigidity enhancement treatment in Example 1.

[0035] Figure 3 Example 1: A schematic diagram of the process of filling the foamed sheet with thermal insulation material powder and then placing it in a vacuum bag for vacuum sealing.

[0036] Figure 4 : Cross-sectional view of the insulation board product obtained in Example 1.

[0037] Figure 5 Example 2: A cross-sectional view of the structure of the foamed sheet using only microporous breathable material (without a filter layer).

[0038] Figure 6 Example 3: A schematic diagram of the structure of the foamed sheet with split spliced ​​sidewalls.

[0039] Figure 7Comparative Example 1: Schematic diagram of the damage state of a traditional insulation board without a buffer layer in a puncture resistance test.

[0040] Figure 8 Comparative Example 2: Schematic diagram showing the warping and detachment of the buffer layer in a traditional externally bonded insulation board during construction.

[0041] Explanation of the labels in the diagram:

[0042] 1-Foamed sheet / elastic buffer layer; 11-Bottom wall; 12-Side wall; 13-Receiving cavity; 14-Inner wall surface; 15-Outer surface; 16-Joint (Example 3); 2-Breathable micropores; 3-Filter layer; 4-Rigid support layer; 41-Ventilation hole; 5-Insulation material powder / Insulation board core; 6-Vacuum bag; 61-Heat seal strip; 62-Vacuum cavity; 63-Top cover; Workbench; 64, 8-Aggregate; 81-Break point; 82-Water seepage area; 83-Warped end; 84-Outer buffer layer. Detailed Implementation

[0043] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0044] I. Overview of the working principle of this invention

[0045] This invention addresses the engineering challenge of kiln inner wall insulation panels being easily punctured by concrete aggregates and damaged by cement slurry seepage during construction. It provides an integrated solution that simultaneously functions as a molding mold and a permanent protective layer. Its core working principle is as follows:

[0046] 1. Box-shaped buffer layer preforming: Foamed sheets are hot-pressed into a box-shaped structure with a bottom wall and side walls. This box-shaped structure serves as both a mold for the subsequent forming of the insulation powder and a permanent puncture-resistant protective layer during construction.

[0047] 2. Air permeability treatment: To address the air impermeability problem caused by the closed-cell structure of foamed sheets, through-hole micropores are formed by mechanical needle punching, laser drilling, etc., and an air permeable and leak-proof filter layer is composited on the inner wall surface, so that air can be smoothly discharged while the heat insulation powder is effectively blocked, thus making it compatible with vacuum packaging process.

[0048] 3. Vacuum-forming-bonding-integration: The foamed sheet is used as a mold to fill the heat-insulating powder and then vacuum-sealed as a whole. During the vacuuming process, the negative pressure causes the foamed sheet to shrink inward evenly and fit tightly with the powder. The powder is compacted into a dense blank, while the foamed sheet is permanently attached to the surface of the blank, forming an integrated protective structure with "zero gaps".

[0049] 4. Comprehensive protection layout: The box-shaped structure of the foamed sheet covers the bottom and four sides of the core, while the top is open (to facilitate adhesion to the kiln wall during construction), achieving five-sided protection and completely eliminating the weak links of traditional solutions with no side protection.

[0050] 5. Optional reinforced structure: The outer surface is reinforced with a rigid support layer to prevent vacuum deformation, and a release layer is provided to prevent adhesion to the vacuum bag, resulting in a wider process window and more stable product quality.

[0051] Step-by-step instructions

[0052] It should be noted that the present invention places the hot pressing process of the foamed sheet before the air permeability treatment, which has the following technical necessity:

[0053] (1) Avoid deformation or blockage of microporous structure during hot pressing: If micropores are formed by needle punching, laser and other air permeability treatments first, the foamed sheet will flow again under high temperature and high pressure during subsequent hot pressing, which may cause the formed micropores to be compressed and closed, the pore size to be uneven or the position to shift, affecting the air permeability consistency.

[0054] (2) Ensure reliable bonding between the filter layer and the inner wall surface: The filter layer is usually fixed to the inner wall of the foamed sheet by hot melt adhesive or spot bonding. If the filter layer is bonded first and then hot-pressed, the high temperature may cause the filter layer material to shrink, melt or fail to bond, reducing the reliability of filtration.

[0055] (3) Ensure the dimensional accuracy of the box-shaped structure: The foamed sheet is first formed into a box shape, and its inner wall surface is continuous and flat, which facilitates accurate positioning during subsequent micropore processing and avoids uneven distribution of micropores due to sheet deformation.

[0056] Therefore, the present invention explicitly defines "hot pressing before permeability treatment" as an important technical feature to ensure stable product performance and repeatable process.

[0057] The technical solution of the present invention will be described in detail below with reference to specific embodiments and accompanying drawings.

[0058] II. Example 1: Integrated seamless box structure (optimal implementation)

[0059] This embodiment fully demonstrates all the steps of the preparation method of the present invention and obtains an insulation board product with optimal protective performance. Figures 1 to 4 .

[0060] 1. Pre-forming of foamed sheets — Figure 1 The structure shown

[0061] like Figure 1 As shown, this embodiment uses ethylene-vinyl acetate copolymer (EVA) foamed sheets with a thickness of 1.2 mm and a density of 65 kg / m³. These sheets are then hot-pressed at 120–125°C and 8 MPa for 15 seconds to form an integrated box-like structure. This structure has the following characteristics:

[0062] Bottom wall 11: Dimensions 300mm × 300mm, extending horizontally;

[0063] Side wall 12: height 50mm, bottom wall 11 extends vertically upward on all four sides, transitioning with the bottom wall 11 at rounded corners (R=5mm), continuous without joints;

[0064] Receiving cavity 13: An upward-opening cavity formed by the bottom wall 11 and the side wall 12, with a volume consistent with the target insulation plate;

[0065] Inner wall surface 14: All inner surfaces of the receiving cavity 13 are smooth and continuous.

[0066] Figure 1 The geometric features of the box-shaped foamed sheet are shown in a three-dimensional sectional view. The relative positions of the bottom wall 11, side wall 12, cavity 13 and inner wall surface 14 are clearly visible. The thickness of each wall is uniform and there are no splicing marks.

[0067] 2. Breathability treatment and rigidity enhancement — Figure 2 The structure shown

[0068] (1) Air permeability treatment

[0069] A CNC needle punching machine is used to puncture from the inner wall surface 14 towards the outer wall, forming breathable micropores 2 that penetrate the thickness direction on the bottom wall 11 and side wall 12 of the foamed sheet 1. The needle tip diameter is 0.25 mm, and the measured pore diameter of the micropores 2 after rebound is approximately 45 μm, with a pore density of 12 pores / cm².

[0070] Subsequently, a layer of 25 g / m² polyethylene terephthalate (PET) short-fiber nonwoven fabric is laminated onto the inner wall surface 14 as filter layer 3, and fixed by hot melt adhesive. Filter layer 3 is approximately 0.12 mm thick, has an air permeability ≥1200 L / m²·s, and a maximum pore size of 35 μm, which can effectively prevent the escape of heat-insulating powder while ensuring free air passage.

[0071] (2) Rigid reinforcement treatment

[0072] A 0.15mm thick PET transparent sheet is laminated onto the outer surface 15 of the foamed sheet 1 as a rigid support layer 4. This PET sheet is pre-drilled with ventilation holes 41, each corresponding to a specific location of the micropores 2, using laser drilling. The hole diameter is 100μm, and the center deviation of the holes is ≤0.2mm. The lamination is performed using acrylic pressure-sensitive adhesive vacuum lamination to ensure that the ventilation holes 41 are aligned and connected to the micropores 2.

[0073] (3) Release layer setting

[0074] A 3-5 μm thick silicone oil release agent is sprayed onto the outer surface of the rigid support layer 4 to form a release layer 7, which prevents it from sticking to the vacuum bag during subsequent vacuum sealing.

[0075] Figure 2 This is a cross-sectional view of the foamed sheet structure in this embodiment. Figure 2 It can be clearly seen that the foamed sheet 1 is sandwiched between the inner wall filter layer 3 and the outer wall rigid support layer 4; the air-permeable micropores 2 penetrate the foamed sheet 1, with their inner ends in contact with the filter layer 3 and their outer ends directly connected to the air vents 41 of the rigid support layer 4, forming a complete gas flow path.

[0076] 3. Filling with insulating powder and vacuum sealing — Figure 3 Process status shown

[0077] The foamed sheet 1 after the above treatment is used as a molding mold and permanent protective layer and placed on the worktable 64 of the vacuum sealing equipment with the opening of the receiving cavity 13 facing upward.

[0078] 1010g of nanoporous calcium silicate insulation powder (bulk density 220kg / m³, particle size D50=18μm) was selected and uniformly filled into the receiving cavity 13 by an automatic feeder, and the surface was scraped smooth.

[0079] like Figure 3 As shown, the foamed sheet 1, along with its internal heat-insulating powder 5, is completely encased in a fiberglass-aluminum foil composite vacuum bag 6, with the bag opening placed flat on the heat-sealing strip 61. The vacuum sealing equipment has a vacuum chamber 62, with a worktable 64 fixed inside the vacuum chamber 62. The heat-sealing strip 61 is also located inside the vacuum chamber 62 and at the edge of the worktable 64. After closing the top cover 63, the vacuum chamber 62 is evacuated for 17 seconds, achieving a vacuum level of -0.082 MPa. During the evacuation process, air from the containing cavity 13 sequentially passes through the filter layer 3, the permeable micropores 2, and the vent 41 into the vacuum bag 6, and is then extracted from the cavity 62 by the vacuum pump. The filter layer 3 effectively blocks the heat-insulating powder 5, preventing any visible powder from escaping.

[0080] Under vacuum negative pressure, the bottom wall 11 and side wall 12 of the foamed sheet 1 shrink inward uniformly, tightly adhering to the heat-insulating powder 5 without gaps; the heat-insulating powder 5 is highly compacted, forming a dense powder blank that conforms to the shape of the receiving cavity 13. After vacuuming is completed, the heat-sealing strip 61 is heated by electricity (voltage level 3, surface temperature 145±5℃) to heat-seal the opening of the vacuum bag 6 for 18 seconds, completing the sealing.

[0081] Figure 3 The spatial relationship of the core components in the vacuum sealing process is fully demonstrated: the vacuum chamber 62 encloses the entire working area, the worktable 64 supports the foamed sheet 1, the vacuum bag 6 covers it, the bag opening extends above the heat sealing strip 61, and the vacuuming direction is perpendicular to the plane of the bag opening and outwards.

[0082] 4. Insulation board product structure — Figure 4 The sectional view shown

[0083] After vacuum sealing is completed, the product is removed from the cover, thus obtaining the heat insulation board described in this invention. Figure 4 This is a cross-sectional view of the finished insulation panel. As shown in the figure:

[0084] Insulation core 5: Located in the center of the product, it is made of compacted insulation powder with a measured density of 395 kg / m³ and its shape is consistent with the cavity 13.

[0085] Elastic buffer layer 1: It is made of breathable EVA foam sheet, with bottom wall 11 and side wall 12, forming an integral seamless box structure, tightly covering the bottom surface and surrounding sides of the core 5, and bonded to the core 5 without gaps.

[0086] Filter layer 3: Composite to the inner wall surface of buffer layer 1, that is, the surface that is in close contact with core 5;

[0087] Rigid support layer 4: Composite to the outer surface of buffer layer 1, with vent holes 41 on it corresponding to and communicating with the breathable micropores 2 in buffer layer 1 (micropores 2 and vent holes 41 are not repeatedly labeled in the figure, please refer to...) Figure 2 );

[0088] Open top surface: The top surface of core 5 is not covered by a buffer layer, which facilitates adhesion to the kiln wall during construction.

[0089] Figure 4 The product features of this invention are clearly shown in a layered structure: from the inside out, they are core 5, filter layer 3, buffer layer 1, and rigid support layer 4, wherein the buffer layer 1 forms a complete cover on the bottom and sides, and the top surface is open. The positions of the bottom wall 11 and the side wall 12 and their fit with the core 5 are clearly visible.

[0090] 5. Effects of this embodiment

[0091] Testing showed that the insulation board in this embodiment withstood a puncture load (φ5mm hemispherical indenter) of 38.5N at the bottom center and 29.2N at the side wall center. After simulated pouring and vibration during construction, the vacuum bag remained intact with no water leakage. The vacuum sealing time was 17 seconds with no powder leakage. This fully meets the stringent requirements for waterproofing and puncture resistance in kiln interior construction.

[0092] III. Example 2: Low-cost solution with only microporous air permeability (corresponding to) Figure 5 )

[0093] This embodiment is basically the same as Embodiment 1, the main difference being that filter layer 3 is omitted to reduce material costs. Its structure is as follows: Figure 5 As shown.

[0094] like Figure 5 As shown, the foamed sheet 1 (in this embodiment, a 1.5mm thick polyethylene foamed sheet) is formed with through-hole micropores 2 by mechanical needle punching. The density of micropores 2 is increased to 16 pores / cm², and the pore diameter is about 35μm. The rigid support layer 4 (PET sheet) has ventilation holes 41 with a pore diameter of 80μm, which are aligned and composite with the micropores 2. There is no filter layer.

[0095] The vacuum sealing step uses the same vacuum sealing equipment as in Example 1. This equipment has a vacuum chamber 62, a worktable 64 and a heat sealing strip 61, and the sealing process parameters are the same as in Example 1.

[0096] During vacuum sealing, the vacuuming time was 16 seconds, slightly faster than in Example 1, but a trace amount of powder escaped from micropore 2 without contaminating the heat seal strip. The product's puncture resistance to bottom surface load was 36.1N, and to sidewall load was 27.5N, slightly lower than in Example 1, but still meeting general construction requirements. This example is suitable for production scenarios with lower cleanliness requirements and cost sensitivity.

[0097] Figure 5 The structural features of micropores 2 directly penetrating the foamed sheet 1 and aligning with the vent holes 41 without a filter layer are clearly shown. Figure 2 This presents a stark contrast.

[0098] IV. Example 3: Split-type splicing structure (comparative example, corresponding) Figure 6 )

[0099] This embodiment serves as a comparative example to verify the necessity of a seamless, integrated structure, and its structure is as follows: Figure 6 As shown.

[0100] like Figure 6 As shown, the foamed sheet 1 is manufactured using a split splicing method: the bottom wall 11 and the four side walls 12 are cut separately and bonded together with hot melt adhesive to form a box-shaped structure, with visible splicing seams 16 at the splicing points. The remaining processes are the same as in Example 1 (including needle-punched micropores, filter layer 3, rigid support layer 4, etc.).

[0101] The vacuum sealing step uses the same vacuum sealing equipment and parameters as in Example 1.

[0102] Test results show that the bottom surface has a puncture resistance of 37.9 N, which is comparable to that of Example 1; however, the side wall has a puncture resistance of only 18.5 N, and the strength at splice joint 16 decreased by 37%; slight water seepage occurred at the side wall splice joint 16 during the construction simulation. Figure 6 The location of the splicing seam 16 is highlighted by magnification, which is a weak point in the structure, proving that the integral seamless box structure defined by the present invention has substantial technical effect.

[0103] V. Example 4: PTFE microporous membrane filtration layer and aluminum plate rigid support layer scheme

[0104] This embodiment demonstrates other material options for the filter layer and rigid support layer to support the material range defined in this invention.

[0105] The foamed sheet 1 is made of 2.0mm thick polypropylene (PP) foamed sheet, which is hot-pressed into a large-size box structure of 600mm×600mm×100mm. For air permeability, micropores 2 (pore diameter 50μm, density 10 pores / cm²) are formed by needle punching. A 0.08mm thick expanded polytetrafluoroethylene (ePTFE) microporous membrane is laminated onto the inner wall surface as a filter layer 3 (average pore diameter 0.5μm, air permeability ≥800L / m²·s). For rigidity reinforcement, a 0.3mm thick 5052 aluminum alloy plate is used as a rigid support layer 4. Ventilation holes 41 (pore diameter 200μm) corresponding to the micropores 2 are created by laser drilling, and epoxy resin structural adhesive is applied under pressure.

[0106] The release layer is coated with a fluorocarbon coating. Subsequent steps, such as filling with calcium silicate powder and vacuum sealing, are the same as in Example 1.

[0107] The vacuum sealing process uses the same equipment structure and heat sealing process as in Example 1.

[0108] Test results: Vacuuming time 18 seconds (slightly increased due to filter membrane resistance), no powder leakage; bottom surface puncture load resistance 52.3N (due to aluminum plate reinforcement); vacuum deformation of large-size products is only 0.2mm. This embodiment demonstrates that both the PTFE microporous membrane and the metal foil rigid layer can achieve the purpose of this invention and are suitable for large-size, high-load-bearing scenarios.

[0109] VI. Example 5: Scheme of glass fiber filter paper filter layer and PP sheet rigid support layer

[0110] This embodiment further demonstrates other material combinations. The foamed sheet 1 is a 1.0mm thick polyethylene (PE) foamed sheet, the filter layer 3 is made of glass fiber filter paper (0.15mm thick, maximum pore size 30μm), and the rigid support layer 4 is made of porous polypropylene (PP) sheet (with its own through-hole structure, requiring no alignment or drilling). The remaining processes are the same as in Embodiment 1.

[0111] The vacuum sealing equipment and operation are the same as in Example 1.

[0112] Test results show that: vacuuming time was 17 seconds with no powder leakage; bottom surface puncture load resistance was 37.5N; sidewall puncture load resistance was 28.8N. This embodiment demonstrates that glass fiber filter paper and PP rigid layer are also feasible, and porous PP sheet can simplify the alignment process of ventilation holes.

[0113] VII. Comparative Example 1: Traditional process without buffer layer (corresponding to) Figure 7 )

[0114] This comparative example uses a traditional process: the insulation board core 5 is individually pressed and molded, then directly placed into a fiberglass aluminum foil vacuum bag 6 for vacuum sealing, without any additional cushioning layer. Its damage state is as follows: Figure 7 As shown.

[0115] like Figure 7 As shown, under the pressure of the simulated concrete aggregate 8, the top surface of the vacuum bag 6 is pierced by the sharp aggregate 8, forming a rupture point 81; cement grout seeps into the core 5 from the rupture point 81, forming a water seepage area 82. The test results show that the bottom surface has a puncture load resistance of only 4.2N, the water seepage depth in the core reaches 15-20mm, and local pulverization occurs. Figure 7 The rupture point 81 is marked with an "×", and the water seepage area 82 is represented by radial dashed lines. This visually reflects the failure mode in which the vacuum bag is easily punctured and the core rapidly absorbs water when there is no buffer layer.

[0116] 8. Comparative Example 2: Traditional External Buffer Layer Process (corresponding to) Figure 8 )

[0117] This comparative example simulates an existing external buffer layer scheme: the insulation board core 5 is individually pressed and vacuum-sealed, and a 2.0mm thick PE foam sheet is adhered to the bottom of the vacuum bag 6 as an external buffer layer 84 using double-sided adhesive tape. Its construction failure state is as follows: Figure 8 As shown.

[0118] like Figure 8 As shown, the outer buffer layer 84 is only attached to the bottom surface of the vacuum bag 6, and its edges curl up during handling or vibration, forming a warped end 83. The sidewalls have no protection, and the aggregate 8 directly pierces the vacuum bag 6 from the side, forming a rupture point 81. Cement grout seeps into the core 5, forming a water-permeable area 82. Tests show that the edge warping height of the buffer layer reaches 5-8 mm after simulated handling, and some parts detach during pouring; the sidewall puncture rate is 100%. Figure 8 The relative positions of the external buffer layer 84, warped end 83, side aggregate 8, fracture point 81 and seepage area 82 are clearly shown in the spatial layout, proving that the external application scheme cannot solve the fundamental defects of weak side protection and unreliable buffer layer fixation.

[0119] IX. Summary Table of Effects of Various Embodiments and Comparative Examples

[0120] To clearly compare the technical effects of the various embodiments of the present invention with those of the comparative examples, the key process parameters and performance test data are summarized as follows:

[0121] As can be seen from the table above:

[0122] 1. All embodiments of the present invention (Embodiments 1, 2, 4, and 5) achieve comprehensive protection of the bottom and sides, and the puncture load resistance is increased by 8 to 12 times compared with Comparative Example 1 and by 10% to 60% compared with Comparative Example 2. Moreover, the sidewall protection capability is a breakthrough from zero to one.

[0123] 2. The sidewall puncture load resistance of the integrated seamless box structure (Examples 1, 2, 4, 5) is significantly better than that of the split splicing structure (Example 3), proving that the "continuous seamless" of claim 9 has a substantial technical contribution;

[0124] 3. A variety of air permeability treatment options: the needle punching + filter layer solution (Examples 1, 4, 5) has no powder leakage; the needle punching only solution (Example 2) has a lower cost but has a small amount of leakage. Users can choose flexibly according to the cleanliness requirements.

[0125] 4. The rigid support layer significantly improves the deformation resistance of large-size products (Example 4), and various materials can achieve the purpose of this invention.

[0126] X. Summary of the working principle and beneficial effects of this invention

[0127] Based on the above embodiments and comparative examples, the present invention achieves the following core working principles and produces significant beneficial effects:

[0128] 1. Mold and protection integrated

[0129] The foamed sheet is pre-heat-pressed into a box shape, which also serves as the molding mold for the insulating powder and the permanent protective layer, eliminating the need for separate mold manufacturing and subsequent application of the protective layer, thus achieving "one-time molding and permanent protection".

[0130] 2. Air-permeable and vacuum-compatible process

[0131] By combining a "through-micropore + inner wall filter layer" or a "through-micropore + rigid layer venting hole" design, the originally impermeable closed-cell foam material gains directional air permeability: air can be quickly discharged along the micropore-venting hole path, while powder is effectively blocked by the filter layer. This design is perfectly compatible with existing vacuum packaging production lines, requiring no equipment modification.

[0132] 3. Vacuum negative pressure self-adhesive mechanism

[0133] During the vacuuming process, the foamed sheet shrinks uniformly inward under the pressure difference between the external atmospheric pressure and the internal residual negative pressure, tightly adhering to the powder. After the powder is compacted, the foamed sheet permanently adheres to the core surface, forming a "zero-gap" bonding layer. This mechanism ensures the integrity of the protective layer and the core, completely eliminating the risk of peeling and warping.

[0134] 4. Five-sided surround protection

[0135] The box-like structure naturally covers the bottom and four sides of the core, with only the top surface open, achieving five-sided physical protection. During concrete pouring, the impact of the aggregate first acts on the buffer layer, and the energy is absorbed and dispersed by the elastic foam material, leaving the vacuum bag intact. Compared with Comparative Example 1 (no protection) and Comparative Example 2 (bottom surface protection only), the comprehensive protection advantage of this invention is extremely significant.

[0136] 5. Optional rigidity reinforcement and release design

[0137] For large-size or high-vacuum applications, the outer surface composite rigid support layer effectively resists negative pressure deformation, ensuring product dimensional accuracy; the release layer prevents the buffer layer from sticking to the vacuum bag, facilitating demolding and on-site film removal. These optional features further broaden the applicability of this invention.

[0138] In summary, this invention, through its ingenious integrated design of "box-shaped foamed sheet - breathable treatment - vacuum negative pressure bonding," completely solves the problems of waterproofing and puncture resistance in the construction of kiln inner wall insulation panels. It has outstanding advantages such as simple process, controllable cost, reliable protection, and strong adaptability.

[0139] Finally, the following points should be noted: First, in the description of this application, it should be noted that, unless otherwise specified and limited, the terms "installation", "connection", and "linkage" should be interpreted broadly, and can be mechanical or electrical connections, or internal connections between two components, or direct connections. "Up", "down", "left", "right", etc. are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may change.

[0140] Secondly: The accompanying drawings of the embodiments disclosed in this invention only involve the structures involved in the embodiments disclosed in this invention. Other structures can refer to the general design. In the absence of conflict, the same embodiment and different embodiments of this invention can be combined with each other.

[0141] In conclusion, the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing an insulation board for the inner wall of a kiln, characterized in that: Includes the following steps: Elastic foamed sheets are used to form a box-shaped structure with a bottom wall, side walls and a receiving cavity formed by the bottom wall and side walls before the air permeability treatment. The foamed sheets have an inner wall surface surrounding the receiving cavity. The foamed sheet is subjected to a permeability treatment to give it a permeable structure that allows gas to pass through but prevents solid insulation material powder from passing through. The permeable foamed sheet is used as a molding mold and a permanent protective layer, and is placed on the worktable of the vacuum sealing equipment. The cavity of the foamed sheet is filled with thermal insulation material powder; The foamed sheet, along with the internal thermal insulation powder, is enclosed in a vacuum bag. The vacuum bag is then vacuumed and heat-sealed, causing the thermal insulation powder to form a dense powder blank that conforms to the shape of the cavity under vacuum. Simultaneously, the foamed sheet is tightly fitted to the bottom and sides of the blank, forming an integrated protective structure.

2. The preparation method according to claim 1, characterized in that: The air permeability treatment includes forming a plurality of micropores penetrating the thickness direction on the surface of the foamed sheet, wherein the micropores are formed by at least one of mechanical needle punching, laser drilling or high-pressure hydroentangling.

3. The preparation method according to claim 2, characterized in that: The permeability treatment also includes: applying a permeable filter layer that does not allow solid powder to pass through to the inner wall surface of the foamed sheet.

4. The preparation method according to claim 1, characterized in that: It also includes rigid reinforcement treatment of the foamed sheet: a rigid support layer is laminated on the outer surface of the foamed sheet, the rigid support layer is a porous and breathable structure, or has ventilation holes on it that correspond to the positions of the micropores of the foamed sheet.

5. The preparation method according to claim 1, characterized in that: Before placing the foamed sheet into the vacuum sealing equipment, a release layer is also provided on the outer surface of the foamed sheet or the inner surface of the vacuum bag, wherein the release layer is a release film or a low surface energy coating.

6. The preparation method according to claim 1, characterized in that: The vacuum sealing equipment has a vacuum chamber, the worktable is disposed inside the vacuum chamber, and the vacuum bag is placed on the worktable and is located entirely within the vacuum chamber for vacuuming. The vacuum sealing device also has a heat sealing strip, which is disposed inside the vacuum chamber, and the opening of the vacuum bag is placed on the heat sealing strip for heat sealing.

7. An insulation board for the inner wall of a kiln, prepared by the preparation method according to any one of claims 1 to 6.

8. The insulation board according to claim 7, characterized in that: The insulation board has an elastic buffer layer, which is made of a breathable foamed sheet. The elastic buffer layer has a bottom wall and side walls, forming an integrated box-shaped structure, and covers the bottom surface and surrounding sides of the insulation board core, and is tightly fitted and seamlessly bonded to the insulation board core. The elastic buffer layer is provided with breathable micropores that penetrate its thickness, its inner wall surface is composited with a breathable and leak-proof filter layer, and its outer surface is composited with a rigid support layer. The rigid support layer is provided with vent holes corresponding to the positions of the breathable micropores. The filter layer is at least one of non-woven fabric, microporous polytetrafluoroethylene membrane or glass fiber filter paper. The rigid support layer is at least one of polyethylene terephthalate sheet, polypropylene sheet, or metal foil.

9. The insulation board according to claim 8, characterized in that: The elastic buffer layer is a one-piece thermoformed box-shaped structure with a continuous, seamless bottom wall and four side walls, providing comprehensive protection for the bottom and four sides of the insulation board core.

10. The insulation board according to claim 8, characterized in that: The elastic buffer layer is made of at least one of polyethylene foam sheet, ethylene-vinyl acetate copolymer foam sheet, or polypropylene foam sheet, and its thickness is 0.5-2.0 mm.

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