Fireproof door core board

Abstract

A fireproof door core, the raw materials and their weight percentages are as follows: Component A: binder 25-40%, heat insulation material 20-30%, modified expanded vermiculite 30-40%, high temperature expanding agent 4-10%, aluminum hydroxide 4-10%, water-retaining agent 4-6%, and component B is water. The modified expanded vermiculite is prepared by the following steps: (1) the vermiculite is partially expanded and calcined; (2) acrylic acid monomer, sodium hydroxide, acrylamide monomer, initiator potassium persulfate, crosslinking aid pentaerythritol polyglycidyl ether, partially expanded vermiculite, and water are taken, stirred evenly and ultrasonically dispersed to obtain a first reaction solution, and placed in a reaction vessel to react and obtain a gel substance; (3) the gel substance is initially crushed and dried, then further pulverized in a ball mill, and then surface crosslinked modified to obtain fireproof expanded vermiculite with water absorption properties.

Description

Technical Field

[0001] This invention relates to a fireproof door core board, and more particularly to a fireproof door core board containing a water-retaining agent and its manufacturing process. Background Technology

[0002] With my country's increasing urbanization and rising urban population density, buildings are becoming increasingly taller, placing significant pressure on fire prevention. Without reliable fire protection products and strict regulatory measures, fires in high-rise buildings, especially skyscrapers, can have devastating consequences. Fire doors have long been installed in fire escape routes, acting as a barrier to protect lives and property. Currently, commonly used fire doors are mostly made of steel, steel-wood, or composite materials of metal and inorganic materials, all of which are non-flammable and possess high resistance to high-temperature deformation. However, steel fire doors are very heavy and inconvenient to open and close. Furthermore, due to the high thermal conductivity of metal, the temperature on the unexposed side of the metal fire door rises rapidly during a fire, significantly hindering evacuation and fire rescue efforts. Fire doors mainly consist of a door frame, door core, engineered wood panels, and hardware. From a fire-resistant and heat-insulating perspective, the fire door core plays the most important and crucial role.

[0003] According to the requirements of the new fire door standard GB12955-2008 for fire door core materials, fire door core materials need to have the following properties: (1) During the burning process of a fire, the fire door core material needs to maintain heat insulation and integrity, and the unexposed side of the fire door core should not be deformed. This is the most important property that the core material must have. (2) The core material should be lightweight, otherwise the fire door will be too heavy, which will affect production, transportation, installation and use. The most suitable density of the core material is less than 0.4 g / cm3. Therefore, the fire door core must have a porous structure. (3) The core material should have the necessary strength and toughness. However, as we all know, the strength and toughness of porous materials decrease very quickly as the density decreases. (4) The core material should be non-toxic and harmless. During the fire-resistant process, the smoke toxicity should meet the ZA2 level requirements. In addition, in order to meet market requirements, it also needs to have the characteristics of high productivity and low cost.

[0004] Currently, the main fireproof door core materials on the market are porous air-entrained magnesium oxide / magnesium chloride boards (referred to as porous air-entrained magnesium oxychloride boards) and perlite boards. However, these materials suffer from defects such as crumbling upon burning, efflorescence, and corrosiveness. Perlite boards, on the other hand, exhibit severe shrinkage and deformation upon burning, and poor fire resistance and heat insulation. Existing technology CN101555121A discloses a novel fireproof and heat-insulating composite perlite board and its manufacturing method, which possesses excellent mechanical strength and good thermal and sound insulation capabilities. However, its heat insulation and fireproof performance fails to meet the increasingly stringent market requirements. Currently, the fire resistance and heat insulation limit of fireproof roller shutters made from commonly available fireproof door core materials is tested according to the provisions of GB / T 7633 in the national standard GB14102-2005. The method of determining loss of fire resistance and heat insulation based on average temperature rise generally results in a fire resistance limit of no more than 2 hours.

[0005] Meanwhile, in order to further improve the fireproof and heat-insulating performance of fire door cores, many companies in the industry have conducted many beneficial explorations. For example, CN115304344A discloses a fireproof and heat-insulating filler for steel fire doors. This patent adds a water-retaining agent to common heat-insulating and fireproof core materials. Water molecules are retained in the filler by the polymer water-retaining agent. When one side of the door panel is exposed to fire, the hardened filler absorbs heat and releases water molecules at the same time. The water molecules evaporate and take away a large amount of heat, thereby effectively slowing down the heating rate of the entire door panel and effectively improving the fireproof and heat-insulating performance. However, since the water-retaining agent contains a large amount of water, if too much is used, it will first lead to the core material forming material having too low strength. In addition, when exposed to fire, while a large amount of water evaporates, the water-retaining agent shrinks and forms a large number of voids, causing the strength of the fireproof core material to drop sharply, which can easily lead to burning shrinkage and deformation, resulting in collapse.

[0006] In the patent application CN202310795005.7 filed by the inventor on June 30, 2023, the inventor discovered that a composite structure formed by incompletely expanded vermiculite and water-absorbing resin can better improve fire resistance. However, in practical applications, our company has found that after the above-mentioned type of fire-resistant material is stored in a dry space for a long time, especially in the dry autumn and winter seasons, the fire resistance of the fire-resistant board material decreases to a certain extent compared with the initial laboratory test results, indicating an unstable fire resistance performance. Summary of the Invention

[0007] This invention provides a fireproof door core board with long-term stable fire resistance. The fireproof door core board is characterized by being composed of the following raw materials, with the names and weight percentages of the raw materials as follows: Component A: 25-40% binder, 20-30% thermal insulation material, 30-40% modified expanded vermiculite, 4-10% high-temperature expanding agent, 4-10% aluminum hydroxide, and 4-6% water-retaining agent. The above percentages are expressed as weight percentages based on the total mass of component A; Component B: water, wherein the mass ratio of component A to component B is 1:(1.5-2.5).

[0008] The binder is one or a combination of several of hemihydrate gypsum, cement, and lime.

[0009] The thermal insulation filler is one or a combination of several of the following: perlite, conventional expanded vermiculite, sepiolite wool, and mica;

[0010] The high-temperature expanding agent is expandable graphite;

[0011] The water-retaining agent is a polyacrylic acid polymer resin, polyacrylamide, and polyvinyl alcohol;

[0012] The modified expanded vermiculite is prepared by the following steps:

[0013] (1) Incomplete expansion calcination of vermiculite: take vermiculite raw material, remove impurities, and put it into a rotary furnace at a temperature of 700-1000℃, heat and expand for 10-20 seconds, and after discharge, incompletely expanded vermiculite is obtained with a bulk density of 1000-1200kg / m3.

[0014] (2) Take acrylic acid monomer, sodium hydroxide, acrylamide monomer, potassium persulfate initiator, pentaerythritol polyglycidyl ether crosslinking aid, incompletely expanded vermiculite, and water, stir evenly and ultrasonically disperse for 20-40 minutes to obtain the first reaction solution, and place it in a reaction vessel for reaction at a temperature of 80-100℃ for 0.5-2 hours to obtain a gel substance; wherein, the mass ratio of acrylic acid monomer, acrylamide monomer, and incompletely expanded vermiculite is (2-4):(0.4-0.6):6;

[0015] (3) The gel material is initially crushed, dried at 150-200℃, and then further pulverized in a ball mill until a fire-resistant expanded vermiculite with water absorption properties and a particle size of 0.6-1.0mm is obtained.

[0016] (4) Surface modification of fire-resistant expanded vermiculite

[0017] A surface crosslinking solution was prepared by mixing 1,3-propanediol, trimethylolpropane triglycidyl ether, ethanol, and tetrabromobisphenol A in a specific ratio. The mass ratio of the surface crosslinking solution to fire-retardant expanded vermiculite with water absorption properties was (0.5-4):100. A measured amount of fire-retardant expanded vermiculite with water absorption properties was placed in a high-speed stirrer, and the surface crosslinking solution was evenly sprayed onto its surface. After stirring for 8-15 minutes, the expanded vermiculite was placed in an oven and subjected to surface crosslinking at 60-150℃ for 0.5-1.5 hours to obtain the final product.

[0018] The mass ratio of 1,3-propanediol, trimethylolpropane triglycidyl ether, ethanol and tetrabromobisphenol A is 1:1:2:1.

[0019] The mass ratio of the surface crosslinking solution to fire-retardant expanded vermiculite with water absorption properties is 1:100. The stirring time is 10 minutes, the surface temperature is 80℃, and the crosslinking time is 1 hour.

[0020] The rotary kiln operates at a temperature of 850-950℃ and has a heating expansion time of 12-15 seconds.

[0021] The heating expansion time is 13 seconds.

[0022] The bulk density of incompletely expanded vermiculite is 1000-1100 kg / m3.

[0023] In step (2), the stirring speed in the reactor is 1200-1800 rpm.

[0024] In step (2), the mass ratio of acrylic monomer to incompletely expanded vermiculite is 1:2.

[0025] In step (2), the mass ratio of water to incompletely expanded vermiculite is (15-25):6.

[0026] This invention, developed through extensive research by researchers in actual production, utilizes in-situ polymerization to allow most of the water-absorbing resin to enter the interlayer of the incompletely expanded vermiculite. This significantly reduces the negative impact of the strong water absorption of the water-absorbing resin on the durability and strength of the refractory material, thereby greatly improving its refractory properties while maintaining its strength.

[0027] The amount of water used is not excessive. Due to the water-absorbing properties of vermiculite, a large amount of water will enter the interlayer of the expanded vermiculite, and a large number of reactive monomers will be dispersed within it. During the reaction, superabsorbent polymers will polymerize in situ within the interlayer of the expanded vermiculite to form a superabsorbent polymer resin. Ultimately, a fire-retardant material will be formed with the superabsorbent polymer resin embedded inside the expanded vermiculite and the expanded vermiculite forming the outer shell. Of course, it is unavoidable that a small amount of superabsorbent resin will remain on the surface of the expanded vermiculite. If too much water is used, a large amount of water will also remain on the outside of the vermiculite, causing a large amount of acrylic acid to react on the surface of the expanded vermiculite, resulting in a large amount of superabsorbent resin being exposed on the outside of the expanded vermiculite, thus reducing the fire resistance of the material. Therefore, in step 2 of this application, the mass ratio of water to incompletely expanded vermiculite is (15-25):6.

[0028] In preparing the first reaction solution, the inventors discovered that conventional dispersion and stirring could not achieve the technical objective of this invention. Extensive research revealed that ultrasonic dispersion facilitates the rapid penetration of water and reactive monomers such as acrylic acid and acrylamide into the interlayer of expanded vermiculite. Conventional dispersion, on the other hand, results in the formation of a large amount of water-absorbing resin on the surface of the expanded vermiculite.

[0029] By adopting the above technical solution, the present invention has at least the following beneficial effects:

[0030] (1) By adjusting the amount of water, water-absorbing polymer monomers and expanded vermiculite, and by using an ultrasonic dispersion process, most of the monomers are polymerized in situ in the interlayer of the expanded vermiculite, thus forming a composite particle with expanded vermiculite as the shell and water-absorbing polymer material coated on it, which is an expanded vermiculite that has both water absorption and fire resistance properties.

[0031] (2) In the modified expanded vermiculite, the expanded vermiculite and the water-absorbing polymer have strong water absorption properties. The two work together to fill the internal interlayer of the expanded vermiculite with water-absorbing and expanding polyacrylic acid water-absorbing resin. The expanded water-absorbing resin can also increase the interlayer distance of the expanded vermiculite. At the same time, the external surface can maintain the strength of the expanded vermiculite as an inorganic mineral filler. In this way, the water absorption performance of the modified expanded vermiculite can be significantly improved, and it can also play a reinforcing role in fireproof materials, avoiding the negative impact of poor strength of water-absorbing resin on the strength of fireproof materials.

[0032] (3) When the fire-retardant material containing the above-mentioned modified expanded vermiculite is burned, a large amount of water evaporates first, taking away a large amount of heat. Although the water-absorbing resin inside the expanded vermiculite will shrink, it does not significantly affect the strength of the fire-retardant material. At the same time, further heating causes the incompletely expanded vermiculite to expand further, thus forming a huge heat-insulating void inside the expanded vermiculite. It can be seen that the modified expanded vermiculite produces a dual fire-retardant effect of water evaporation heat absorption and hollow heat insulation, which greatly improves the fire-retardant performance of the fire-retardant material and avoids the problems of insufficient strength of water-absorbing polymer materials and local collapse of fire-retardant materials caused by water evaporation.

[0033] (4) In actual production, we found that there is also a small amount of water-absorbing resin on the surface of vermiculite. At high temperature, it will shrink, resulting in material layout defects. We chose uncommon incompletely expanded vermiculite, which will expand further at high temperature. This can effectively make up for the space reduced by the shrinkage of the external water-absorbing resin, effectively maintain the strength of the fireproof material at high temperature, and delay its high temperature deformation time.

[0034] (5) In practical applications, our company has found that after prolonged storage in dry spaces, especially during the dry autumn and winter seasons, the fire resistance of fireproof boards using unmodified expanded vermiculite decreases compared to laboratory test results. Analysis by our R&D engineers indicates that although expanded vermiculite has strong water absorption, the surface of the vermiculite also contains directly exposed water-absorbing resin, and the porous structure of vermiculite cannot completely cover the core water-absorbing resin. Therefore, prolonged dry storage, especially in autumn and winter, leads to a significant loss of moisture from the water-absorbing resin, resulting in a certain degree of decrease in actual fire resistance.

[0035] Based on the company's existing innovative technology, this invention utilizes a surface crosslinking solution prepared with 1,3-propanediol, trimethylolpropane triglycidyl ether, ethanol, and tetrabromobisphenol A to perform crosslinking modification, thereby increasing the crosslinking density of the water-absorbing resin on the surface of expanded vermiculite. This results in a high-density crosslinked interpenetrating network structure, making it difficult for moisture in the water-absorbing and fire-retardant expanded vermiculite to evaporate, thus exhibiting good water retention. Even after long-term storage in a dry environment, it still maintains good fire-retardant performance.

[0036] (6) In the modification of expanded vermiculite, tetrabromobisphenol A was added in the form of chemical crosslinking. Through chemical crosslinking with expanded vermiculite, the dispersibility of tetrabromobisphenol A was improved by utilizing the dispersibility of expanded vermiculite in inorganic fireproof materials. At the same time, the three different fireproofing mechanisms of chemical fireproofing of tetrabromobisphenol A, heat insulation fireproofing of expanded vermiculite and water evaporation fireproofing of water-absorbing resin were organically combined and complemented each other, so that the modified expanded vermiculite exhibited better fireproofing performance.

[0037] (7) The fireproof door core panel of the present invention uses modified incompletely expanded vermiculite, which increases the amount of water-retaining agent while maintaining the strength of the fireproof material. At the same time, because the expanded vermiculite is coated on the outside, the loss of moisture under normal conditions is reduced, and the water retention of the water-absorbing material is improved. When the temperature is high, the semi-expanded vermiculite expands rapidly, and the increase in the interlayer distance is conducive to the rapid evaporation of moisture in the interlayer water-retaining agent, which carries away a large amount of heat. It can be seen that the combined effect of the incompletely expanded vermiculite and the water-retaining agent inside the interlayer achieves the synergistic effect of water absorption, water retention, reinforcement and fireproofing. The roller shutter door containing this fireproof door core has passed the test of GB14102-2005 standard, with a fire resistance limit of more than 2.5 hours and the best effect is close to 3 hours. Moreover, it has passed the European standard fire protection standard named EN1634-1:2014 by customer testing.

[0038] (8) In addition to the existing door core material formula, aluminum hydroxide is added to this door core material. When aluminum hydroxide is exposed to high temperature, it dehydrates to form heat-resistant aluminum oxide. On the one hand, the evaporation of water improves the heat insulation performance, and on the other hand, the formation of heat-resistant aluminum oxide improves the strength of the material at high temperature. Detailed Implementation

[0039] The technical solution of the invention will be described in detail below with reference to specific embodiments.

[0040] Example 1

[0041] (1) The preparation method of fireproof expanded vermiculite A includes the following steps: (1) Incomplete expansion and calcination of vermiculite: take vermiculite raw material to remove impurities and put it into a rotary furnace at a temperature of 850℃, heat and expand for 13 seconds, and after discharge, incomplete expanded vermiculite is obtained with a bulk density of 1050kg / m3.

[0042] (2) 300g of acrylic acid monomer, 120g of sodium hydroxide, 50g of acrylamide monomer, 1g of potassium persulfate initiator, 0.1g of pentaerythritol polyglycidyl ether crosslinking aid, 600g of incompletely expanded vermiculite, and 2000g of water were stirred evenly to obtain the first reaction solution, and the reaction was carried out in a reaction vessel at a reaction temperature of 85℃ for 1 hour to obtain a gel substance;

[0043] (3) The gel material is initially crushed, dried at 170°C, and then further pulverized in a ball mill until a fire-resistant expanded vermiculite with water absorption properties and a particle size of 0.6-1.0 mm is obtained.

[0044] (4) Surface modification of fire-resistant expanded vermiculite

[0045] A surface crosslinking solution was prepared by mixing 1,3-propanediol, trimethylolpropane triglycidyl ether, ethanol, and tetrabromobisphenol A in a specific ratio. The mass ratio of the surface crosslinking solution to fire-retardant expanded vermiculite with water-absorbing properties was 1:100. A measured amount of fire-retardant expanded vermiculite with water-absorbing properties was placed in a high-speed stirrer, and the surface crosslinking solution was evenly sprayed onto its surface. After stirring for 10 minutes, the expanded vermiculite was placed in an oven and subjected to surface crosslinking at 80°C for 1 hour to obtain the final product, fire-retardant expanded vermiculite A with water-absorbing properties.

[0046] The mass ratio of 1,3-propanediol, trimethylolpropane triglycidyl ether, ethanol and tetrabromobisphenol A is 1:1:2:1.

[0047] Example 2

[0048] (1) The preparation method of fireproof expanded vermiculite A includes the following steps: (1) Incomplete expansion and calcination of vermiculite: take vermiculite raw material to remove impurities and put it into a rotary furnace at a temperature of 850℃, heat and expand for 13 seconds, and after discharge, incomplete expanded vermiculite is obtained with a bulk density of 1050kg / m3.

[0049] (2) 300g of acrylic acid monomer, 120g of sodium hydroxide, 50g of acrylamide monomer, 1g of potassium persulfate initiator, 0.1g of pentaerythritol polyglycidyl ether crosslinking aid, 600g of incompletely expanded vermiculite, and 2000g of water were stirred evenly to obtain the first reaction solution, and the reaction was carried out in a reaction vessel at a reaction temperature of 85℃ for 1 hour to obtain a gel substance;

[0050] (3) The gel material is initially crushed, dried at 170°C, and then further pulverized in a ball mill until a fire-resistant expanded vermiculite B with water absorption properties and a particle size of 0.6-1.0 mm is obtained.

[0051] Example 3

[0052] Based on Example 1, the incompletely expanded vermiculite was replaced with commercially available expanded vermiculite with a bulk density of 2500 kg / m³. The other preparation steps remained the same, resulting in modified expanded vermiculite C.

[0053] Example 4

[0054] (1) The preparation method of fireproof expanded vermiculite A includes the following steps: (1) Incomplete expansion and calcination of vermiculite: take vermiculite raw material to remove impurities and put it into a rotary furnace at a temperature of 850℃, heat and expand for 13 seconds, and after discharge, incomplete expanded vermiculite is obtained with a bulk density of 1050kg / m3.

[0055] (2) 300g of acrylic acid monomer, 120g of sodium hydroxide, 50g of acrylamide monomer, 1g of potassium persulfate initiator, 0.1g of pentaerythritol polyglycidyl ether crosslinking aid, and 2000g of water were stirred evenly to obtain the first reaction solution, and the reaction was carried out in a reaction vessel at a reaction temperature of 85℃ for 1 hour to obtain a gel substance.

[0056] (3) The gel material is initially crushed, dried at 170°C, and then further pulverized in a ball mill. 600g of incompletely expanded vermiculite is added for blending to obtain blended modified expanded vermiculite D.

[0057] Example 5

[0058] Based on Example 1, the amount of acrylic monomer was adjusted from 300g to 600g, while the other preparation steps remained the same, to obtain modified expanded vermiculite E.

[0059] Example 6

[0060] (1) The preparation method of fireproof expanded vermiculite A includes the following steps: (1) Incomplete expansion and calcination of vermiculite: take vermiculite raw material to remove impurities and put it into a rotary furnace at a temperature of 850℃, heat and expand for 13 seconds, and after discharge, incomplete expanded vermiculite is obtained with a bulk density of 1050kg / m3; without further modification, expanded vermiculite F is obtained.

[0061] Example 7 (Tetrabromobisphenol A blend modification)

[0062] Fire-resistant expanded vermiculite with water absorption properties and a particle size of 0.6-1.0 mm was obtained by using steps (1)-(3) in Example 1.

[0063] (4) Surface modification of fire-resistant expanded vermiculite

[0064] A surface crosslinking solution was prepared by mixing 1,3-propanediol and trimethylolpropane triglycidyl ether in a specific ratio. The mass ratio of the surface crosslinking solution to fire-retardant expanded vermiculite with water-absorbing properties was 0.4:100. A measured amount of fire-retardant expanded vermiculite with water-absorbing properties was placed in a high-speed stirrer, and the surface crosslinking solution was evenly sprayed onto its surface. After stirring for 10 minutes, the expanded vermiculite was placed in an oven and subjected to surface crosslinking at 80°C for 1 hour to obtain fire-retardant expanded vermiculite with water-absorbing properties. The mass ratio of 1,3-propanediol to trimethylolpropane triglycidyl ether was 1:1.

[0065] Ethanol and tetrabromobisphenol A are mixed in a mass ratio of 2:1 to obtain a tetrabromobisphenol A alcohol solution, which is then sprayed onto the surface of fire-retardant expanded vermiculite obtained by the aforementioned process under high-speed stirring, thereby obtaining fire-retardant expanded vermiculite G.

[0066] The mass ratio of the tetrabromobisphenol A modified solution to fire-retardant expanded vermiculite (based on unmodified vermiculite) is 0.6:100. The mass ratio of 1,3-propanediol, trimethylolpropane triglycidyl ether, ethanol, and tetrabromobisphenol A is 1:1:2:1.

[0067] Example 8

[0068] Fire-resistant expanded vermiculite with water absorption properties and a particle size of 0.6-1.0 mm was obtained by using steps (1)-(3) in Example 1.

[0069] (4) Surface modification of fire-resistant expanded vermiculite

[0070] A surface crosslinking solution was prepared by mixing 1,3-propanediol, trimethylolpropane triglycidyl ether, and ethanol in a specific ratio. The mass ratio of the surface crosslinking solution to the water-absorbing, fire-retardant expanded vermiculite was 1:100. A measured amount of the water-absorbing, fire-retardant expanded vermiculite was placed in a high-speed stirrer, and the surface crosslinking solution was evenly sprayed onto its surface. After stirring for 10 minutes, the expanded vermiculite was placed in an oven and surface crosslinked at 80°C for 1 hour to obtain the final product, water-absorbing, fire-retardant expanded vermiculite H.

[0071] The mass ratio of 1,3-propanediol, trimethylolpropane triglycidyl ether, and ethanol is 1:2:2.

[0072] Example 9

[0073] The fireproof door core panel is made from the following raw materials: 30% cement as adhesive, 25% thermal insulation material (perlite: conventional expanded vermiculite: sepiolite wool in a mass ratio of 10:10:5), 30% modified expanded vermiculite, 5% high-temperature expanding agent expandable graphite, 5% aluminum hydroxide, and 5% water-retaining agent polyacrylic acid polymer resin. All percentages are by weight, based on the total mass of component A. Component B: water, where the mass ratio of component A to component B is 1:1.8. At room temperature, tap water in a mass ratio of 1.8 is added to component A, and the mixture is stirred at high speed to form a stable slurry. This slurry is then poured into the roller shutter door panel and allowed to harden naturally.

[0074] Among them, fireproof door cores A, B, C, D, E, F, G, and H are obtained by using modified expanded vermiculite A, B, C, D, E, F, G, and H prepared in Examples 1-6.

[0075] Fire resistance performance test

[0076] The thermal insulation limit was tested according to the provisions of GB / T 7633 in the national standard GB14102-2005. The specimen was deemed to have lost its fire resistance and thermal insulation properties when the average back-fired temperature rise of the specimen exceeded the initial average surface temperature of the specimen by 140℃. The corresponding time was recorded in mm.

[0077] The fire resistance test was divided into two groups. The first group was tested 3 days after the fire-resistant door core board was manufactured, and the second group was tested 3 months after the fire-resistant door core board was manufactured and stored in a dry environment.

[0078] Sample type Modified expanded vermiculite type Fire resistance limit (3 days) Fire resistance limit (3 months) Fireproof door core board A Modified expanded vermiculite A 2.9H 2.7h Fireproof door core board B Modified expanded vermiculite B 2.8h 2.4h Fireproof door core board C Modified expanded vermiculite C 2.3h 2.0h Fireproof door core board D Modified expanded vermiculite D 1.8h 1.6h Fireproof door core board E Modified expanded vermiculite E 2.1h 1.8h Fireproof door core board F Conventional expanded vermiculite F 1.7h 1.7h Fireproof door core board G Modified expanded vermiculite G 2.7h 2.5h Fireproof door core board H Modified expanded vermiculite H 2.5h 2.3h

[0079] It is evident that the flame retardant properties of fireproof door core boards with specially modified expanded vermiculite are significantly improved compared to those with directly blended or other conventionally modified expanded vermiculite.

[0080] The fire retardant performance of expanded vermiculite without added tetrabromobisphenol A (TBBPA) was slightly reduced, while the performance of expanded vermiculite modified with TCBPA blends was lower than that of chemically cross-linked expanded vermiculite. This is presumably due to the slightly poor compatibility and dispersibility of TCBPA in inorganic material systems. However, chemical modification with TCBPA improves the cross-linking density and hydrophobicity of the vermiculite surface, enhancing the long-term stability of its fire retardant performance. Furthermore, the well-dispersed TCBPA itself acts as a fire retardant, significantly improving the fire retardant properties of expanded vermiculite.

Claims

1. A fire door core panel, characterized in that, The following raw materials are mixed to form the present application, and the raw material names and weight percentages are as follows: component A: binder 25-40%, heat insulation material 20-30%, modified expanded vermiculite 30-40%, high-temperature expanding agent 4-10%, aluminum hydroxide 4-10%, water-retaining agent 4-6%, the above percentages are by weight, based on the total mass of component A; component B: water, wherein the mass ratio of component A to component B is 1:(1.5-2.5), wherein the modified expanded vermiculite is prepared by the following steps: (1) incomplete expansion calcination of vermiculite: the vermiculite raw material is impurity-removed and put into a rotary furnace with a temperature of 700-1000℃, heated and expanded for 10-20 seconds, and the incomplete expanded vermiculite with a bulk density of 1000-1200 kg / m3 is obtained after discharging; (2) taking acrylic acid monomer, sodium hydroxide, acrylamide monomer, initiator, crosslinking aid, incomplete expanded vermiculite, and water, stirring uniformly and ultrasonic dispersing for 20-40 minutes to obtain a first reaction solution, and placing it in a reaction kettle for reaction at a reaction temperature of 80-100℃ for 0.5-2 hours to obtain a gel material; wherein the mass ratio of acrylic acid monomer, acrylamide monomer, and incomplete expanded vermiculite is (2-4):(0.4-0.6):6; (3) the gel material is preliminarily broken, dried at 150-200℃, and then further pulverized in a ball mill until the fireproof expanded vermiculite with water absorption performance with a particle size of 0.6-1.0 mm is obtained; (4) surface modification of the fireproof expanded vermiculite 1,3-propanediol, trimethylolpropane triglycidyl ether, ethanol, and tetrabromobisphenol A are prepared into a surface crosslinking solution according to a certain proportion; the mass ratio of the surface crosslinking solution to the fireproof expanded vermiculite with water absorption performance is (0.5-4):100; a certain amount of the fireproof expanded vermiculite with water absorption performance is put into a high-speed stirrer, the surface crosslinking solution is uniformly sprayed onto the surface of the fireproof expanded vermiculite, and after stirring for 8-15 minutes, the above expanded vermiculite is placed in an oven for surface crosslinking at 60-150℃ for 0.5-1.5 hours to obtain the final product of the fireproof expanded vermiculite.

2. The fire door core panel of claim 1, wherein, The binder is one or a combination of several of semi-hydrated gypsum, cement, and calcium carbonate; the heat insulation filler is one or a combination of several of perlite, conventional expanded vermiculite, sepiolite, and mica.

3. The fire door core panel of claim 1, wherein, The high-temperature expanding agent is expandable graphite; the water-retaining agent is polyacrylic acid-based high molecular resin, polyacrylamide, and polyvinyl alcohol.

4. The fire door core panel of claim 1, wherein, The working temperature of the rotary furnace is 850-950℃, and the heating expansion time is 12-15 seconds.

5. The fire door core panel of claim 1, wherein, The heating expansion time is 13 seconds.

6. The fire door core panel of claim 1, wherein The bulk density of the incomplete expanded vermiculite is 1000-1100 kg / m3.

7. The fire door core panel of claim 1, wherein The stirring speed in the reaction kettle in step (2) is 1200-1800 revolutions per minute.

8. The fire door core panel of claim 1, wherein, In step (4), the mass ratio of 1,3-propanediol, trimethylolpropane triglycidyl ether, ethanol, and tetrabromobisphenol A is 1:1:2:

1.

9. The fire door core panel of claim 1, wherein, In step (2), the mass ratio of water to incomplete expanded vermiculite is (15-25):

6.

10. The fire door core panel of claim 1, wherein, In step (2), the crosslinking aid is pentaerythritol polyglycidyl ether.