Fire door filling process and use thereof

Abstract

This invention discloses a fire door filling process and its application, relating to the field of fire door manufacturing. Existing fire door core panels suffer from problems such as poor overall structural stability and insufficient nail-holding power due to the easy pulverization of perlite particles and low overall strength. This invention first performs microbial mineralization on perlite particles, generating an inorganic mineral coating on the particle surface and forming an inorganic mineral support framework within the pores by controlling reaction parameters, thus obtaining high-strength mineralized perlite particle units. Then, two particle units of different densities are prepared and mixed separately with a fire-retardant binder. Finally, the mixed low-density and high-density materials are filled into the central and peripheral areas of a mold, and then pressed and cured to form an integrated core panel with a gradient structure of low density in the middle and high density around the edges. The core panel prepared by this method has a stable structure, is not easily pulverized, and significantly improves the strength and nail-holding power of the edge areas, making it suitable for high-performance fire door manufacturing.

Description

Technical Field

[0001] This invention relates to the field of fire door manufacturing, and in particular to a fire door filling process and its application. Background Technology

[0002] Fire doors are crucial passive fire-resistant components in modern buildings. Their fire resistance integrity, thermal insulation performance, and long-term structural stability fundamentally depend on the fire-resistant core panel inside. To balance thermal insulation and load-bearing requirements, expanded perlite has become the mainstream aggregate for core panels due to its lightweight and excellent thermal insulation properties. However, perlite core panels made using traditional physical mixing molding processes have a series of inherent defects caused by the material's inherent weaknesses and simplistic structural design, seriously affecting the reliability, service life, and ease of installation of fire doors.

[0003] First, traditional perlite particles suffer from insufficient mechanical properties and stability. As a porous and brittle siliceous material, perlite particles have low compressive strength, making them highly susceptible to breakage and pulverization under the stress of door pressing, transportation, installation, and repeated opening and closing. This leads to voids and uneven density within the door core panel, directly weakening its thermal insulation continuity, causing uncontrollable degradation of fire resistance, and causing bulging and deformation of the door panel, affecting sealing and aesthetics. Although the industry has attempted to improve it using "mineralization" methods such as surface coating with cement slurry and inorganic adhesives, these methods are essentially physical coatings. The resulting reinforcing layer has weak bonding with the perlite matrix and cannot penetrate deep into the pores of the particles to achieve internal reinforcement. Under stress or processing, the coating layer is prone to detachment, exposing the still fragile particles inside, failing to fundamentally solve the pulverization problem. Simultaneously, the open porous structure of perlite makes it highly hygroscopic, easily absorbing moisture and increasing its weight in humid environments, leading to the failure of the adhesive within the core panel, resulting in hollowing and peeling, further reducing its structural strength and dimensional stability.

[0004] Secondly, the existing homogeneous filling structure of door core panels has design limitations. Most products use a uniform density filling method, which cannot be optimized for the actual stress characteristics of fire doors. The edges of the door leaf, the hinge mounting sides, and the lock mounting points bear the main installation stress, impact force, and repeated opening and closing loads, making them weak points prone to deformation and cracking. The homogeneous structure lacks sufficient strength redundancy in these critical areas, resulting in poor overall deformation resistance and easy edge damage. This directly causes the industry-recognized problem of "insufficient nail-holding power" when installing hardware on wooden or steel-wood fire doors—screws cannot obtain a strong nail-holding force in the homogeneous and fragile core panel, seriously affecting installation strength and long-term safety. Furthermore, the homogeneous and brittle material also makes door leaf shaping (such as milling grooves and drilling) difficult, easily leading to chipping and cracking during processing, affecting production yield and product refinement.

[0005] Therefore, the industry urgently needs a revolutionary solution that requires breakthroughs in both "intrinsic material strengthening" and "innovative structural design." Firstly, it necessitates the development of a deep modification technology that fundamentally enhances the strength of perlite particles and seals their water-absorbing pores, rather than simply surface coating. Secondly, it requires the design of a heterogeneous core panel structure to achieve graded application of materials, ensuring overall lightweighting while specifically strengthening weak mechanical areas. This will be key to improving the overall performance and reliability of fire doors. Summary of the Invention

[0006] The technical problem to be solved and the technical task proposed by this invention is to improve and refine existing technical solutions, and to provide a fireproof door core board, its manufacturing method, and a fireproof door leaf, so as to overcome the technical defects of existing perlite door core boards, such as easy powdering, easy moisture absorption, insufficient nail holding power for hardware installation, and insufficient edge strength due to uniform structure. To this end, this invention adopts the following technical solution.

[0007] A fire door filling process includes the following steps: 1) Material mineralization treatment: Microbial mineralization treatment is carried out on perlite particles. By controlling the reaction parameters, an inorganic mineral coating is generated on the surface of the perlite particles, and an inorganic mineral support skeleton is formed in the internal pores, thereby obtaining mineralized perlite particle units with enhanced mechanical properties. This step fundamentally enhances the performance of perlite aggregate. The inorganic mineral coating formed on the surface improves the water resistance and corrosion resistance of the aggregate, while the inorganic mineral skeleton formed inside significantly enhances the compressive strength and crush resistance of the particles, thus solving the technical problems of easy pulverization and low strength of traditional perlite from the source. 2) Zoned material preparation: Based on step 1), prepare two types of mineralized perlite particle units with at least a first density and a second density, wherein the second density is greater than the first density; mix the particle units of different densities with fire-retardant binders respectively to obtain a low-density core material mixture and a high-density core material mixture; This step achieves material differentiation by preparing mineralized perlite particle units of different densities, laying the foundation for the subsequent construction of heterogeneous gradient structures, enabling the door core panel to meet the requirements of overall lightweighting and local high strength. 3) Gradient Filling and Pressing: The low-density core material mixture is filled into the central area of ​​the molding die, and the high-density core material mixture is filled into the surrounding edge areas of the molding die. Pressure is then applied to solidify the material, forming an integrated door core panel with a low-density center and a high-density perimeter. This "light in the center, strong around the perimeter" gradient density structure, while ensuring the overall lightweight nature of the door panel, significantly enhances the mechanical strength and nail-holding power of key stress-bearing areas such as door edges, hinges, and lock installation, thereby improving the overall deformation resistance of the door panel.

[0008] As a preferred technical means: In step 1), the controlled reaction parameters include at least one of calcium ion concentration, bacterial solution concentration, reaction time, and pH value. By controlling these key parameters, the process and extent of the mineralization reaction can be flexibly controlled, thereby stably and reproducibly preparing mineralized perlite particle units with the expected density and mechanical properties to meet the production needs of door core panels of different specifications.

[0009] As a preferred technical means: In step 1), the inorganic mineral coating and / or inorganic mineral support framework comprises calcium carbonate and / or calcium phosphate. Calcium carbonate and calcium phosphate are common biomineralization products with excellent mechanical properties and chemical stability. The coating and framework formed by them can effectively improve the strength, hardness and weather resistance of perlite, and the raw materials are readily available and the process is environmentally friendly.

[0010] As a preferred technical means: In step 2), the fire-retardant adhesive is a phosphate adhesive. Phosphate adhesives have the characteristics of high fire resistance, high bonding strength, stable performance at high temperatures, and environmental friendliness with no release of harmful gases. When combined with mineralized perlite particles, they can further ensure the overall fire safety and structural integrity of the door core panel.

[0011] As a preferred technical means, the average compressive strength of the mineralized perlite particle units obtained in step 1) is not less than 7 MPa. This indicator ensures that the mineralized particle units themselves have very high individual strength, far superior to traditional perlite. This is the basis for forming high-strength door core panels and directly contributes to the excellent impact resistance and fracture resistance of the final product.

[0012] As a preferred technical means: In step 3), the high-density structural layer formed after curing of the surrounding edge area has a thickness of 45-60mm. This thickness range is the optimal balance point verified by practice, which can provide a sufficiently wide reinforced area to ensure the firmness of the hardware installation and the overall rigidity of the door edge, while avoiding excessive weight increase and cost increase due to excessive thickness, thus achieving optimization of performance and economy.

[0013] A fireproof door core board is prepared by any of the above-mentioned fireproof door filling processes. As a direct product of the aforementioned processes, the fireproof door core board inherits all its advantages: the internal particles of the core board are not easily pulverized, the structure is stable, and the moisture resistance is good; it has a gradient density structure, with a lightweight central area and high strength and strong nail-holding power at the edges; the overall performance is uniform and stable, providing core component support for the manufacture of high-performance fireproof doors.

[0014] A fireproof door leaf is provided, wherein the interior of the door leaf is filled with the aforementioned fireproof door core board. Due to the use of a fireproof door core board with a gradient high-strength structure, the overall weight of the fireproof door leaf is reasonable, the door leaf structure is stable and not easily deformed, and the load-bearing capacity of its edges and hardware installation parts is significantly enhanced, greatly improving the reliability and service life of hinges, locks, and other installations. At the same time, the excellent performance of the core board ensures the long-term fire resistance integrity and heat insulation of the door leaf.

[0015] A method for manufacturing a fireproof door leaf includes the following steps: L1) Provides the fireproof door core panel as described above; L2) The door core panel is milled and shaped according to the shape and size of the front and back panels; L3) The formed door core board is combined with the front and back panels of the steel plate to form a door leaf. Because the door core board itself has high strength and stable structure, it is not easy to chip or crack during the milling process. It has high processing precision and high yield. After being combined with the panel, it can form a solid and reliable whole door leaf, realizing the simultaneous improvement of production efficiency and product quality.

[0016] Beneficial Effects: By combining microbial mineralization material strengthening technology with gradient density structural design, this technical solution systematically solves the technical defects of traditional perlite fireproof door core boards, such as easy pulverization, easy moisture absorption, insufficient nail-holding force for hardware installation, and insufficient edge strength due to uniform structure. The resulting fireproof door core board and fireproof door products have comprehensive advantages, including a robust and stable internal structure, high compressive strength, resistance to pulverization, moisture resistance and anti-hollowing, excellent nail-holding force at edges and in hardware installation areas, lightweight overall design with strong resistance to deformation, and good processing performance. These advantages significantly improve the reliability, safety, and service life of fireproof doors, and demonstrate promising prospects for industrial applications. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the door core board manufacturing process in this invention.

[0018] Figure 2 This is a schematic diagram of perlite particle mineralization in this invention.

[0019] Figure 3 This is a schematic diagram of the manufacturing process of the fireproof door leaf in this invention.

[0020] Figure 4 This is a schematic diagram of the fire door leaf structure in this invention.

[0021] Figure 5 This is the present invention. Figure 4 Enlarged schematic diagram of part A in the middle.

[0022] In the diagram: 1. Perlite particles; 2. Inorganic mineral coating; 3. Inorganic mineral support framework; 4. Door core panel; 5. Front panel; 6. Back panel; 401. Low-density area; 402. High-density area. Detailed Implementation

[0023] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings.

[0024] Example 1 like Figure 1 As shown, the manufacturing method of the fireproof door core board 4 in this embodiment mainly includes the following steps: S1: Material mineralization treatment: Expanded perlite particles 1 of a certain particle size are provided as raw materials. The perlite particles 1 are immersed in a prepared microbial mineralization reaction solution. The reaction solution contains a calcium source, bacterial solution, and nutrients such as urea. In this embodiment, calcium chloride is used as the calcium source, and Bacillus pasteurellii bacterial solution is used, which has urease-producing activity.

[0025] By precisely controlling key parameters such as calcium ion concentration, bacterial concentration, reaction time, and pH value in the reaction system, the metabolic activities of microorganisms are guided. During this process, the carbonate ions induced by the microorganisms combine with calcium ions to form a dense calcium carbonate inorganic mineral coating 2 on the surface of perlite particles 1. Simultaneously, the reaction products also penetrate into the pores inside the particles, forming a calcium carbonate inorganic mineral support framework 3, such as... Figure 2 As shown. In this embodiment, the calcium ion concentration was controlled at 0.5-1.0 mol / L, the OD600 value of the bacterial culture was controlled at 0.8-1.2, the reaction time was 12-48 hours, and the pH value was maintained at 8.0-9.0.

[0026] After this step, the mechanical properties of the perlite particle units are fundamentally enhanced. Tests show that their average compressive strength increased from less than 2 MPa before treatment to no less than 7 MPa, a 4-5 fold increase compared to the original particles. Simultaneously, the surface coating effectively seals most of the surface pores, significantly reducing water absorption by approximately 20% and greatly improving moisture resistance. Furthermore, the inorganic mineral layer formed on the surface of the perlite particles can isolate them from the contact and erosion of corrosive ions in pH 3-11 solutions, providing excellent corrosion resistance.

[0027] S2: Zoned material preparation: Based on the mineralization process in step S1, at least two types of mineralized perlite particle units with different densities are prepared by adjusting different combinations of reaction parameters, such as increasing the calcium ion concentration and extending the reaction time. The lower density particle unit is defined as the first density particle unit, and the higher density particle unit as the second density particle unit.

[0028] The two types of mineralized perlite particles with different densities were respectively mixed with a fire-retardant binder. The fire-retardant binder was preferably a phosphate-based binder, prepared from aluminum phosphate solution, ceramic fiber powder, a curing agent, and a suitable amount of water, exhibiting excellent fire resistance and bonding strength. After mixing, low-density core material mixtures and high-density core material mixtures were obtained for later use.

[0029] S3: Gradient Filling and Suppression: Prepare a molding die that matches the size of the door panel 4. The interior of the die is divided into a central area and four surrounding edge areas.

[0030] First, the low-density core material mixture prepared in step S2 is filled into the central region of the mold. Then, the high-density core material mixture is filled into the four outer edges of the mold. The materials in the two regions form a clear partition within the mold.

[0031] The mold containing the material is fed into a press, pressed under a set pressure, and then cured at a certain temperature. After demolding, a one-piece fireproof door core panel 4 is obtained. Figure 5 As shown, the core panel 4 has a distinct gradient structure: the central part is a lightweight, low-density region 401, and the surrounding area is a reinforced, high-density region 402. Measurements show that the thickness H of the surrounding high-density region 402 is controlled within an optimized range of 45-60 mm. In this embodiment, the thickness is 50 mm to ensure sufficient edge strength.

[0032] The fireproof door core board 4 prepared by the above method is essentially a direct product of the aforementioned manufacturing method. The structural features of the core board 4 are as described above. Its internal particles, due to mineralization treatment, possess high strength and low water absorption. The entire board is firmly bonded together with an adhesive, and through a unique density gradient design of "low in the middle and high around the edges," a balance between lightweighting and reinforcement of key areas is achieved. This core board 4 can be directly used as a modular component for assembling fire doors.

[0033] like Figure 3 As shown, a method for manufacturing a fire door leaf using the aforementioned fireproof door core board 4 includes the following steps: L1: Provides door core panel 4: Provide a fireproof door core board 4 with a gradient structure prepared as described above.

[0034] L2: Milling shaping: Based on the design drawings of the target fire door and the shape and dimensions of the front panel 5 and the back panel 6, CNC milling machines and other processing equipment are used to mill, groove, and drill the fire door core panel 4 to ensure that its shape, lock hole, hinge groove, etc., precisely match the panel requirements. Because the core panel 4 has high strength and uniform structure, the edges are neat and there is no chipping during milling.

[0035] L3: Composite molding: The front panel 5 and back panel 6, pre-molded from steel plates, are prepared. Structural adhesive is applied to the machined surface of the core panel 4, which is then placed between the front panel 5 and back panel 6. After alignment and positioning, it is fed into a composite press for pressure bonding. After pressure curing, the front panel 5, fireproof core panel 4, and back panel 6 are firmly bonded together to form a complete door leaf, as shown below. Figure 4 As shown.

[0036] like Figure 5 As shown, the finished fire door can be obtained by subsequently installing the door frame, hinges, locks, and other hardware. In particular, the hardware can be directly fixed to the door leaf position corresponding to the high-density area 402 around the door core panel 4 with screws. The excellent nail-holding power of this area ensures a firm and reliable installation.

[0037] This invention constructs a mineral skeleton inside perlite particles 1 through microbial mineralization technology, which increases the compressive strength of the individual particles to over 7MPa and effectively seals the water absorption channels, ensuring the long-term structural stability and moisture resistance of the core board from the material source.

[0038] This invention scientifically distributes material properties through a gradient design of a low-density central region 401 and a high-density surrounding region 402. While ensuring the overall lightweight nature of the door panel, it specifically strengthens the edge areas that are subjected to the greatest stress and are most prone to damage, greatly improving the overall deformation resistance and structural reliability of the door panel.

[0039] The high-density 402 area around the perimeter provides a solid base for the installation of hardware, completely solving the industry problem of insufficient nail holding power of traditional fire door core panels 4, making the installation of hinges and locks more secure and extending the service life of fire doors.

[0040] The high-strength, homogeneous core panel 4 makes subsequent processing such as milling and grooving smoother and more precise, reduces processing losses, and improves production efficiency and the precision and quality of finished door panels.

[0041] Example 2 The main difference between this embodiment and Embodiment 1 lies in the reaction product of the microbial mineralization treatment in step S1.

[0042] In this embodiment, the composition of the reaction solution was adjusted (e.g., soluble phosphate was added), and a bacterial strain capable of inducing calcium phosphate deposition was selected. By controlling the reaction parameters, calcium phosphate inorganic mineral coating 2 and inorganic mineral support framework 3 were mainly formed on the surface and within the pores of perlite particles 1. Calcium phosphate also possesses excellent mechanical properties and biocompatibility, and exhibits superior high-temperature resistance. The remaining steps, such as zoned material preparation, gradient filling and pressing, and door leaf composite, are the same as or similar to those in Example 1, ultimately yielding a high-performance gradient structure fireproof door core panel 4 and a fireproof door.

[0043] The above are specific embodiments of the present invention, which demonstrate the outstanding substantive features and significant progress of the present invention. Based on the actual needs of use, equivalent modifications in shape, structure, etc., can be made to it according to the teachings of the present invention, and all such modifications are within the scope of protection of this solution.

Claims

1. A fire door filling process, characterized in that... Includes the following steps: 1) Material mineralization treatment: Microbial mineralization treatment is carried out on perlite particles. By controlling the reaction parameters, an inorganic mineral coating is generated on the surface of the perlite particles, and an inorganic mineral support skeleton is formed in the internal pores, thereby obtaining mineralized perlite particle units with enhanced mechanical properties. 2) Zoned material preparation: Based on step 1), prepare two types of mineralized perlite particle units with at least a first density and a second density, wherein the second density is greater than the first density; mix the particle units of different densities with fire-retardant binders respectively to obtain a low-density core material mixture and a high-density core material mixture; 3) Gradient filling and pressing: The low-density core material mixture is filled into the middle area of ​​the molding die, and the high-density core material mixture is filled into the four edges of the molding die. Then pressure is applied to solidify the material to form an integrated door core panel with a low density in the middle and a high density around the edges.

2. The fire door filling process according to claim 1, characterized in that: In step 1), the controlled reaction parameters include at least one of calcium ion concentration, bacterial concentration, reaction time, and pH value.

3. A fire door filling process according to claim 1 or 2, characterized in that: In step 1), the inorganic mineral coating and / or inorganic mineral support framework comprises calcium carbonate and / or calcium phosphate.

4. The fire door filling process according to claim 1, characterized in that: In step 2), the fire-retardant adhesive is a phosphate-based adhesive.

5. The fire door filling process according to claim 1, characterized in that: The average compressive strength of the mineralized perlite particle units obtained in step 1) is not less than 7 MPa.

6. The fire door filling process according to claim 1, characterized in that: In step 3), the high-density structural layer formed after the surrounding edge area is cured has a thickness of 45-60mm.

7. A fireproof door core panel, characterized in that: It is prepared by any one of the fire door filling processes according to claims 1 to 6.

8. A fireproof door leaf, characterized in that: The door leaf is filled with the fireproof door core board as described in claim 7.

9. A method for manufacturing a fireproof door leaf, characterized in that... Includes the following steps: L1) provides the fireproof door core panel as described in claim 7; L2) The door core panel is milled and shaped according to the shape and size of the front and back panels; L3) The formed door core board is combined with the front and back panels of the door, which are molded from steel plates, to form a door leaf.

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