Basalt short-cut fiber and preparation method thereof, basalt fiber fireproof plate and preparation method and application thereof

Abstract

The application provides basalt chopped fiber and a preparation method thereof, and relates to the technical field of building materials.The continuous fiber bundle obtained after unwinding is subjected to airflow pre-opening in the application, so that the filaments in the fiber bundle are preliminarily separated, the close holding state between the filaments is broken, the generation of chopped bundle filaments and clumps is reduced, and the dispersibility of the prepared basalt chopped fiber is improved; the chopped fiber bundle is subjected to static electricity removal after being chopped, the static electricity generated due to friction in the shearing and conveying process of the fiber is removed, the static adsorption force between the fibers is eliminated, the agglomeration of the chopped fiber due to the electrostatic effect is prevented, the dispersibility is further improved, the bundle filament rate and the loose filament rate of the obtained basalt chopped fiber are low, the dispersibility in the fireproof plate is good, and the mechanical property and the high-temperature resistance of the fireproof plate are improved. Moreover, the low-temperature soft chopping is adopted in the application, so that the obtained basalt chopped fiber has good wettability with a resin or a cement matrix and high interfacial bonding strength.

Description

Technical Field

[0001] This invention relates to the field of building materials technology, specifically to a basalt short-cut fiber and its preparation method, a basalt fiber fireproof board and its preparation method and application. Background Technology

[0002] Basalt fiber, as a high-performance inorganic fiber, possesses excellent characteristics such as high temperature resistance, high strength, corrosion resistance, and flame retardancy, and is widely used in fireproof boards. Its performance directly affects the mechanical strength, high-temperature stability, and service life of the fireproof board. During the production process of fireproof boards, the dispersion performance of basalt chopped fibers and their interfacial bonding performance with the matrix (such as cement, resin, etc.) are key factors determining the overall performance of the fireproof board. If the fibers are not evenly dispersed, local agglomeration is easily formed, leading to stress concentration inside the fireproof board and a decrease in mechanical properties. If the interfacial bonding between the fibers and the matrix is ​​not strong, interfacial debonding is likely to occur under high-temperature conditions, preventing the fibers from effectively exerting their reinforcing and flame-retardant effects.

[0003] The conventional process for producing chopped basalt fibers involves several steps: first, unwinding the basalt filament bobbin to draw out the filaments; then, feeding the continuous filaments into a rotary cutter roller chopped fiber machine, where the filaments are cut and collected under the combined action of the cutter roller and rubber pressure roller. However, the chopped basalt fibers obtained by this process have tightly bound monofilaments, easily forming bundles and clumps. Furthermore, the static electricity generated by friction during the chopping process causes the fibers to attract each other, further exacerbating the agglomeration phenomenon. This severely affects the uniformity of fiber dispersion in the fireproof board matrix, ultimately impacting the mechanical properties and high-temperature resistance of the fireproof board, making it difficult to meet the demands of high-end applications. Summary of the Invention

[0004] In view of this, the purpose of this invention is to provide basalt chopped fibers and their preparation method, basalt fiber fireproof boards and their preparation method, and their applications. The basalt chopped fibers prepared by the method provided by this invention have low bundle ratio and fuzz ratio, and good dispersibility in basalt fiber fireproof boards.

[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solution: This invention provides a method for preparing basalt short-cut fibers, comprising the following steps: The basalt fiber is unwound to obtain a continuous fiber bundle; The continuous fiber bundle is pre-opened by airflow to obtain a fluffy continuous fiber bundle; The fluffy continuous fiber bundle is chopped to obtain a chopped fiber bundle; the chopping temperature is ≤35℃, and the linear speed of the cutting roller is 15~20m / min. The chopped fiber bundles are destaticated to obtain the basalt chopped fibers.

[0006] Preferably, the unwinding includes unwinding using a three-stage tension roller group; the tension of each stage of the tension roller group decreases progressively, and the tension difference between two adjacent stages of the tension roller group is ≤5N.

[0007] Preferably, the airflow velocity for pre-opening is 5~8m / s, and the angle between the airflow direction and the conveying direction of the continuous fiber bundle is 30~45°.

[0008] Preferably, the static electricity removal includes static electricity removal using high-voltage ion air; The output voltage of the high-pressure ion wind is 4.5~5.5kV, the working frequency is 50~60Hz, and the current of a single ion rod is 0.2~0.3mA / m; The high-pressure ion air source includes air, with a working pressure of 0.3~0.5MPa, a fiber surface wind velocity of 8~12m / s, and an air volume of 0.25~0.4m³. 3 / (min·m).

[0009] The present invention provides basalt chopped fibers prepared by the preparation method described above, wherein the length of the basalt chopped fibers is 3-8 mm, the bundle rate is 6.9-7.8%, and the filament rate is 3.2-3.9%.

[0010] This invention provides a basalt fiber fireproof board, comprising, by weight parts, 8-15 parts of chopped basalt fibers, 40-55 parts of cement-fly ash composite cementitious material, 20-30 parts of inorganic functional filler, 1-3 parts of reinforcing fiber, 0.3-0.8 parts of dispersant, and 0.5-1.5 parts of waterproofing agent; The basalt short-cut fiber is the basalt short-cut fiber as described in claim 5.

[0011] Preferably, the cement in the cement-fly ash composite cementitious material includes sulfoaluminate cement and / or silicate cement; The mass percentage of fly ash in the cement-fly ash composite cementitious material is 15-30%; The inorganic functional filler includes one or more of expanded perlite, silica fume and aluminum hydroxide; The reinforcing fibers include polyvinyl alcohol fibers and / or aramid fibers; The dispersant includes polycarboxylic acid dispersants; The waterproofing agent includes an organosilicon waterproofing agent.

[0012] This invention provides a method for preparing the basalt fiber fireproof board described in the above technical solution, characterized by comprising the following steps: A dry mix is ​​obtained by mixing cement-fly ash composite cementitious material, inorganic functional filler, dispersant and waterproofing agent; Basalt short-cut fibers and reinforcing fibers were dispersed in water to obtain a fiber dispersion. The dry mixture and the fiber dispersion are mixed to obtain a mixed slurry; The mixed slurry is molded and then cured to obtain basalt fiber fireproof board.

[0013] Preferably, the molding process includes vacuum vibration filter pressing molding; The pressure for vacuum vibration filtration molding is 0.8~1.5MPa, and the time is 5~10min; The curing temperature is 60~80℃, the humidity is ≥90%, and the time is 24~48h.

[0014] This invention provides the application of the basalt fiber fireproof board described in the above technical solution or the basalt fiber fireproof board prepared by the above technical solution in the interior and exterior walls of buildings, subway tunnels or ship bulkheads.

[0015] This invention provides a method for preparing basalt chopped fibers, comprising the following steps: unwinding basalt precursor fibers to obtain a continuous fiber bundle; pre-opening the continuous fiber bundle with airflow to obtain a fluffy continuous fiber bundle; chopping the fluffy continuous fiber bundle to obtain a chopped fiber bundle; wherein the chopping temperature is ≤35℃ and the linear speed of the cutting roller is 15~20m / min; and destaticating the chopped fiber bundle to obtain the basalt chopped fibers. This invention pre-opens the continuous fiber bundles obtained after unwinding with airflow, causing the monofilaments inside the fiber bundles to initially separate, breaking the tight cohesion between the monofilaments, reducing the generation of bundles and clumps after shaving, and improving the dispersibility of the obtained basalt chopped fibers. After shaving, the chopped fiber bundles are destaticated to remove the static electricity generated by friction during shearing and conveying, eliminate the electrostatic adsorption force between fibers, and prevent the chopped fibers from agglomerating due to electrostatic effects, further improving the dispersion performance. The resulting basalt chopped fibers have low bundle and fuzz rates, good dispersion performance in fireproof boards, and thus improve the mechanical properties and high-temperature resistance of the fireproof boards. Furthermore, conventional basalt chopped fiber cutting uses high-speed roller shearing, which easily generates localized instantaneous high temperatures, leading to thermal aging and melting adhesion of the fiber surface. This also results in rough fiber end faces, splitting, and noticeable burrs. Additionally, the fiber surface itself is inert and has low surface energy, resulting in poor wettability between the basalt chopped fiber and the fireproof board matrix, insufficient interfacial bonding strength, and an inability to fully utilize the fiber's reinforcing and flame-retardant properties. In contrast, this application uses low-temperature gentle chopping, controlling the chopping temperature to ≤35℃ and employing a roller linear speed of 15~20m / min, thus avoiding the localized instantaneous high temperatures generated by high-speed shearing. This process leads to thermal aging and melting adhesion of the fiber surface, achieving gentle and neat cutting of the fibers. This results in good wettability and high interfacial bonding strength between the basalt chopped fibers and the resin or cement matrix. Under high-temperature conditions, the basalt chopped fibers do not debond from the matrix, fully leveraging their reinforcing and flame-retardant properties. At the same time, it avoids the thermal damage to the basalt chopped fibers caused by localized high temperatures from conventional high-speed shearing, reducing fuzzing and splitting phenomena, and ensuring the structural integrity and performance stability of the basalt chopped fibers. Consequently, when applied to fireproof boards, it improves the overall quality and service life of the fireproof boards.

[0016] Furthermore, by employing a three-stage tension roller group for unwinding and limiting the tension of each stage of the tension roller group to decrease progressively, and ensuring that the tension difference between two adjacent stages of the tension roller group is ≤5N, the present invention avoids the formation of fuzz and splitting of basalt filaments due to uneven tension and excessive friction during the conveying process, thereby further improving the wettability of basalt chopped fibers. Detailed Implementation

[0017] This invention provides a method for preparing basalt short-cut fibers, comprising the following steps: The basalt fiber is unwound to obtain a continuous fiber bundle; The continuous fiber bundle is pre-opened by airflow to obtain a fluffy continuous fiber bundle; The fluffy continuous fiber bundle is chopped to obtain a chopped fiber bundle; the chopping temperature is ≤35℃, and the linear speed of the cutting roller is 15~20m / min. The chopped fiber bundles are destaticated to obtain the basalt chopped fibers.

[0018] Unless otherwise specified, the materials and equipment used in this invention are all commercially available products in the field.

[0019] This invention unwinds basalt precursor fibers to obtain continuous fiber bundles.

[0020] In this invention, the basalt precursor fiber can be used in the form of a basalt precursor fiber spool; the diameter of the precursor fiber in the basalt precursor fiber spool can be 9~17μm, specifically 9μm, 11μm, or 17μm; in this invention, the unwinding can include unwinding using a three-stage tension roller group; the tension of each stage of the tension roller group decreases progressively, and the tension difference between two adjacent stages of the tension roller group is ≤5N. This invention uses a three-stage tension roller group for progressive unwinding, with the tension of each stage of the tension roller group decreasing progressively. By controlling the tension difference between two adjacent stages of the tension roller group to ≤5N, the basalt precursor fiber is smoothly conveyed.

[0021] After obtaining a continuous fiber bundle, the present invention pre-opens the continuous fiber bundle with airflow to obtain a fluffy continuous fiber bundle.

[0022] In this invention, the airflow velocity for pre-opening can be 5~8m / s, specifically 6m / s or 7m / s; the angle between the airflow direction for pre-opening and the conveying direction of the continuous fiber bundle can be 30~45°, specifically 35° or 40°.

[0023] After obtaining a fluffy continuous fiber bundle, the present invention chops the fluffy continuous fiber bundle to obtain a chopped fiber bundle.

[0024] In this invention, the shaving temperature is ≤35℃, and can be 30~35℃, specifically 31℃, 32℃, 33℃, or 34℃; the linear speed of the cutting roller used for shaving is 15~20m / min, specifically 16m / min, 17m / min, 18m / min, or 19m / min. In this invention, the pressure roller used for shaving can be an elastic buffer pressure roller; the ratio of the gap between the cutting roller and the pressure roller to the fiber diameter of the fluffy continuous fiber bundle can be 1.2~1.5:1, specifically 1.3:1 or 1.4:1.

[0025] After obtaining the chopped fiber bundle, the present invention removes static electricity from the chopped fiber bundle to obtain the basalt chopped fiber.

[0026] In this invention, the static electricity removal may include using a high-voltage ion wind; the output voltage of the high-voltage ion wind can be 4.5~5.5kV, specifically 4.8kV or 5kV; the operating frequency of the high-voltage ion wind can be 50~60Hz, specifically 52Hz or 55Hz; the output voltage is AC voltage. This invention uses industrial frequency AC power, resulting in more stable ion balance.

[0027] In this invention, the current of a single ion bar in the high-pressure ion wind can be 0.2~0.3 mA / m, specifically 0.25 mA / m or 0.28 mA / m. This invention uses low current to prevent sparking.

[0028] In this invention, the air source for the high-pressure ion wind can include air, specifically clean, water-free, and oil-free compressed air; the working air pressure of the air source can be 0.3~0.5MPa, specifically 0.35MPa, 0.4MPa, or 0.45MPa; the fiber surface wind velocity of the high-pressure ion wind can be 8~12m / s, specifically 9m / s, 10m / s, or 11m / s; the air volume of the high-pressure ion wind can be 0.25~0.4m³ / s. 3 / (min·m), which can be specifically 0.3m 3 / (min·m) or 0.35m 3 / (min·m); The distance between the high-pressure ion air nozzle and the chopped fiber bundle of the high-pressure ion air can be 10~15cm, specifically 11cm, 12cm, 13cm, 14cm or 15cm.

[0029] After the static removal is completed, the present invention may further include collecting the static-removed fibers obtained by static removal using a flexible conveyor belt and then screening them to obtain basalt short-cut fibers.

[0030] In this invention, the conveying speed of the flexible conveyor belt can be the same as the output speed of the antistatic fibers; the flexible conveyor belt can specifically be a leather-like conveyor belt. This invention uses a flexible conveyor belt to collect antistatic fibers, avoiding end-face damage and fuzz formation caused by impact and friction during collection.

[0031] In this invention, the sieving process may include vibrating sieving. This invention uses vibrating sieving to remove short fibers that are not of the required length and a small amount of impurities, ensuring that the resulting basalt chopped fibers have a uniform length distribution.

[0032] This invention provides basalt chopped fibers prepared by the method described in the above technical solution. In this invention, the length of the basalt chopped fibers is 3-8 mm, specifically 3 mm, 6 mm, or 8 mm; the bundle ratio of the basalt chopped fibers is 6.9-7.8%, specifically 7%, 7.2%, or 7.5%; the filament ratio of the basalt chopped fibers is 3.2-3.9%, specifically 3.4%, 3.6%, or 3.8%; the diameter of the basalt chopped fibers can be 9-17 μm, specifically 9 μm, 11 μm, or 17 μm; the tensile strength of the long fibers of the basalt chopped fibers can be ≥3000 MPa, specifically 3100 MPa, 3200 MPa, 3300 MPa, or 3400 MPa. The basalt short-cut fibers obtained by this invention have uniform and small lengths, low bundle and fuzz rates, good dispersion performance and interfacial compatibility, and have good application prospects in fireproof boards.

[0033] This invention provides a basalt fiber fireproof board, comprising, by weight parts: The ingredients include 8-15 parts chopped basalt fiber, 40-55 parts cement-fly ash composite cementitious material, 20-30 parts inorganic functional filler, 1-3 parts reinforcing fiber, 0.3-0.8 parts dispersant, and 0.5-1.5 parts waterproofing agent. The basalt short-cut fiber is the basalt short-cut fiber described in the above technical solution.

[0034] In this invention, the basalt fiber fireproof board comprises 8-15 parts by weight of chopped basalt fibers, specifically 10, 12, or 14 parts. In this invention, the length of the chopped basalt fibers is 3-12 mm, or 3-6 mm, specifically 4 mm or 5 mm.

[0035] In this invention, the basalt fiber fireproof board comprises 40 to 55 parts of cement-fly ash composite cementitious material, specifically 45 parts, 48 ​​parts, or 50 parts, based on 1 part by mass of the basalt short-cut fiber.

[0036] In this invention, the cement in the cement-fly ash composite cementitious material may include sulfoaluminate cement and / or silicate cement; the mass percentage of fly ash in the cement-fly ash composite cementitious material may be 15-30%, specifically 20% or 25%. This invention improves the fluidity and water retention of the slurry through the cement-fly ash composite cementitious material, reducing bleeding and segregation; it also reduces the amount of mixing water, lowering the water-cement ratio for the same strength; moreover, the fly ash particles are much smaller than cement particles, enabling them to uniformly fill the gaps between cement particles, optimize gradation, reduce the capillary porosity inside the slurry, and significantly improve the matrix density.

[0037] In this invention, the basalt fiber fireproof board comprises 20-30 parts of inorganic functional filler, specifically 23 parts, 25 parts, or 27 parts, based on 1 part by weight of the basalt short-cut fibers. In this invention, the inorganic functional filler may include one or more of expanded perlite, silica fume, and aluminum hydroxide. This invention achieves lightweight board material by adding inorganic functional fillers. Expanded perlite enhances the heat insulation and fire resistance performance through its porous structure, and expands to seal gaps and slow down heat transfer at high temperatures. Silica fume, with its ultrafine aggregates, fills the voids and exerts the activity of volcanic ash, improving the board's density, mechanical strength, and interfacial bonding with the matrix, thus enhancing high-temperature structural stability. Aluminum hydroxide decomposes upon heating, absorbing a large amount of heat and releasing crystal water, which also has the functions of cooling, oxygen isolation, smoke suppression, and toxicity reduction. The alumina generated from the decomposition can also form a dense protective layer to block open flame attack. The synergistic effect of these three components allows the board to simultaneously achieve comprehensive performance such as lightweight and high strength, heat insulation, flame retardancy, fire resistance, and low smoke environmental protection, effectively improving the overall fire resistance limit and service durability.

[0038] In this invention, the basalt fiber fireproof board comprises 1 to 3 parts by weight of reinforcing fiber, specifically 1.5 parts, 2 parts, or 2.5 parts, based on 1 part by weight of the basalt chopped fibers. In this invention, the reinforcing fiber may include polyvinyl alcohol fiber and / or aramid fiber. This invention improves the impact resistance of the basalt fiber fireproof board through the use of reinforcing fibers.

[0039] In this invention, the basalt fiber fireproof board comprises 0.3 to 0.8 parts of dispersant, based on 1 part by mass of the basalt chopped fibers. In this invention, the dispersant may include a polycarboxylic acid dispersant; the molecular weight of the polycarboxylic acid dispersant may be 18,000 to 25,000, specifically 20,000 or 22,000; the degree of polymerization of the main chain of the polycarboxylic acid dispersant may be 30 to 50, specifically 35, 40, or 45; the polydispersity index (PDI) of the polycarboxylic acid dispersant may be ≤1.8, specifically 1.5, 1.6, or 1.7. This invention incorporates polycarboxylate dispersants into basalt fiber fireproof boards. These dispersants adsorb onto the powder particles and fiber surfaces, forming electrostatic repulsion and steric hindrance effects. This breaks up material agglomeration and flocculation, effectively improving slurry fluidity and workability, reducing mixing water consumption, and lowering the water-cement ratio of the system. Simultaneously, it optimizes slurry uniformity, improves the dispersion and distribution of basalt fibers in the matrix, prevents fiber clumping, facilitates dense board forming, reduces internal pores and defects, thereby improving product strength, density, and forming smoothness. It also shortens the setting and hardening cycle, optimizes construction efficiency, and ensures the stable performance of the board's various mechanical and fire-resistant durability properties.

[0040] In this invention, based on 1 part by weight of the basalt chopped fibers, the basalt fiber fireproof board includes 0.5 to 1.5 parts of a waterproofing agent, specifically 0.8 parts, 1 part, or 1.2 parts. In this invention, the waterproofing agent may include an organosilicon waterproofing agent. By adding a waterproofing agent, the organosilicon waterproofing agent can form a hydrophobic protective film in the capillary pores and surface of the board, blocking water seepage channels, significantly reducing the board's water absorption and permeability, and preventing water from penetrating inwards; simultaneously, it does not seal the internal breathable micropores, maintaining the board's breathability and preventing dampness, efflorescence, and peeling; it also enhances the hydrophobic bonding force between the matrix and fiber interface, improving the board's resistance to water erosion, freeze-thaw resistance, and damp heat aging, delaying the strength reduction and fire resistance decline caused by water and fire erosion, and effectively improving the stability and service life of the basalt fiber fireproof board in outdoor and humid environments.

[0041] In this invention, the thickness of the basalt fiber fireproof board can be 6~20mm, specifically 10mm or 15mm; the density of the basalt fiber fireproof board can be 800~1100kg / m³. 3 Specifically, it can be 900 kg / m 3 Or 1000kg / m 3 The thermal conductivity of the basalt fiber fireproof board can be ≤0.08W / (m·K), specifically 0.06W / (m·K), 0.07W / (m·K) or 0.075W / (m·K).

[0042] This invention provides a method for preparing the basalt fiber fireproof board described in the above technical solution, characterized by comprising the following steps: A dry mix is ​​obtained by mixing cement-fly ash composite cementitious material, inorganic functional filler, dispersant and waterproofing agent; Basalt short-cut fibers and reinforcing fibers were dispersed in water to obtain a fiber dispersion. The dry mixture and the fiber dispersion are mixed to obtain a mixed slurry; The mixed slurry is molded and then cured to obtain basalt fiber fireproof board.

[0043] This invention mixes cement-fly ash composite cementitious material, inorganic functional filler, dispersant and waterproofing agent to obtain dry mix.

[0044] This invention disperses basalt chopped fibers and reinforcing fibers in water to obtain a fiber dispersion. In this invention, the dispersion may include stirring; the dispersion time may be 5-10 minutes, specifically 6 minutes or 8 minutes. In this invention, the mass ratio of the total mass of the basalt chopped fibers, cement-fly ash composite cementitious material, inorganic functional filler, reinforcing fibers, dispersant, and waterproofing agent to the mass of water may be 1:0.25-0.35, specifically 1:0.28, 1:0.3, or 1:0.32.

[0045] After obtaining the dry mix and the fiber dispersion, the present invention mixes the dry mix and the fiber dispersion (referred to as the first mix) to obtain a mixed slurry.

[0046] In this invention, the first mixing can be stirring; the mixing time can be 10-15 min, specifically 11, 12, 13 or 14 min.

[0047] After obtaining the mixed slurry, the present invention performs molding and curing on the mixed slurry to obtain basalt fiber fireproof board.

[0048] In this invention, the molding process may include vacuum vibration pressure filtration molding or compression molding; the molding pressure may be 0.8~1.5MPa, specifically 1MPa, 1.2MPa or 1.4MPa; the molding time may be 5~10min, specifically 6min, 7min or 8min.

[0049] In this invention, the curing temperature can be 60~80℃, specifically 62℃, 65℃ or 68℃; the curing humidity can be ≥90%, specifically 92%, 94% or 95%; the curing time can be 24~48h, specifically 30h, 36h or 42h.

[0050] After the curing process is completed, the present invention may further include drying the cured board, then cutting and smoothing it to obtain a basalt fiber fireproof board. In this invention, the drying temperature can be 80~100℃, specifically 85℃, 90℃, or 95℃; the moisture content of the dried board can be ≤5%. In this invention, the smoothing process may include sanding or coating.

[0051] This invention provides the application of the basalt fiber fireproof board described in the above technical solution or the basalt fiber fireproof board prepared by the above technical solution in the interior and exterior walls of buildings, subway tunnels or ship bulkheads.

[0052] To further illustrate the present invention, the solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0053] In all embodiments of the present invention, the basalt precursor fiber was purchased from Jiangsu Tianlong Basalt Continuous Fiber Co., Ltd. Cement: Silicate cement is designated as P·O 52.5; sulfoaluminate cement is designated as R.SAC 52.5. The fly ash is 80 mesh, Grade I fly ash; Expanded perlite is Zhejiang Aske ASC-P650WR; The silica fume was purchased from Shijiazhuang Borui Building Materials Co., Ltd. The aluminum hydroxide was purchased from Zibo Zhenghua Additives Co., Ltd., and the model was ZH-ATH high white ultrafine aluminum hydroxide. Polyvinyl alcohol fiber is SD-PVA high-strength, high-modulus PVA fiber, purchased from Zibo Shengda Chemical. The aramid fiber is Teprolon TF-1000; The polycarboxylic acid dispersant was PCA-100, purchased from Jiangsu Bote New Materials. The silicone waterproofing agent is 549H silicone water-repellent agent; The high-pressure ion air supply has an output voltage of 4.5~5.5kV, an operating frequency of 50~60Hz, a single ion bar current of 0.2~0.3mA / m, an air source of air, an operating air pressure of 0.3~0.5MPa, a fiber surface wind speed of 8~12m / s, and an air volume of 0.25~0.4m³. 3 / (min·m).

[0054] Example 1 Unwinding: A basalt filament bobbin with a diameter of 11μm is placed on an unwinding device and unwinded step by step using a three-stage tension roller group. The tensions of the three-stage tension rollers are set to 25N, 20N and 15N respectively to obtain a continuous fiber bundle.

[0055] Airflow pre-opening: The obtained continuous fiber bundle is conveyed to the pre-opening device, a uniform airflow is introduced, the airflow speed is controlled at 6m / s, and the airflow direction is at a 35° angle with the conveying direction of the continuous fiber bundle. The continuous fiber bundle is pre-opened to obtain a fluffy continuous fiber bundle.

[0056] Low-temperature gentle cutting and online static elimination: The obtained fluffy continuous fiber bundle is fed into a chopped fiber device, using a cutter roller with a linear speed of 18 m / min and an elastic buffer pressure roller. The gap between the cutter roller and the pressure roller is 16 μm, and the chopped fiber bundle is controlled at 30℃. The chopped fiber bundle is then cut to a length of 6 mm. A high-pressure ion nozzle is installed at the outlet of the chopped fiber device, with a distance of 12 cm between the ion nozzle and the chopped fiber bundle. The obtained chopped fiber bundle is then destaticated to obtain destatic fiber.

[0057] Flexible collection and screening: The destatic fibers are collected using a flexible conveyor belt. The speed of the conveyor belt is consistent with the output speed of the destatic fibers. The collected destatic fibers are sent to a 4-stage vibrating screening device for screening to remove fibers and impurities that do not meet the length requirements, thus obtaining basalt short-cut fibers.

[0058] Example 2 Unwinding: A basalt filament bobbin with a diameter of 9μm is placed on an unwinding device and unwound step by step using a three-stage tension roller group. The tensions of the three-stage tension rollers are set to 20N, 15N and 10N respectively to obtain a continuous fiber bundle.

[0059] Airflow pre-opening: The obtained continuous fiber bundle is conveyed to the pre-opening device, a uniform airflow is introduced, the airflow speed is controlled at 5m / s, and the airflow direction is at a 30° angle with the conveying direction of the continuous fiber bundle to perform pre-opening treatment on the continuous fiber bundle to obtain a fluffy continuous fiber bundle.

[0060] Low-temperature gentle cutting and online static elimination: The obtained fluffy continuous fiber bundle is fed into a chopped fiber device, using a cutter roller with a linear speed of 15 m / min and an elastic buffer pressure roller. The gap between the cutter roller and the pressure roller is 12 μm, and the chopped fiber bundle is controlled at 35℃. The chopped fiber bundle is then cut to obtain a chopped fiber bundle with a length of 3 mm. A high-pressure ion nozzle is installed at the outlet of the chopped fiber device, with a distance of 10 cm between the ion nozzle and the chopped fiber bundle. The obtained chopped fiber bundle is then destaticated to obtain destatic fiber.

[0061] Flexible collection and screening: The destatic fibers are collected using a flexible conveyor belt. The speed of the conveyor belt is consistent with the output speed of the destatic fibers. The collected destatic fibers are sent to a three-stage vibrating screening device for screening to remove fibers and impurities that do not meet the length requirements, thus obtaining basalt short-cut fibers.

[0062] Example 3 Unwinding: A basalt filament bobbin with a diameter of 17μm is placed on an unwinding device and unwound step by step using a three-stage tension roller group. The tensions of the three-stage tension rollers are set to 30N, 25N and 20N respectively to obtain a continuous fiber bundle.

[0063] Airflow pre-opening: The obtained continuous fiber bundle is conveyed to the pre-opening device, a uniform airflow is introduced, the airflow speed is controlled at 8m / s, and the airflow direction is at a 45° angle with the conveying direction of the continuous fiber bundle. The continuous fiber bundle is pre-opened to obtain a fluffy continuous fiber bundle.

[0064] Low-temperature gentle cutting and online static elimination: The obtained fluffy continuous fiber bundle is fed into a chopped fiber device, using a cutter roller with a linear speed of 20 m / min and an elastic buffer pressure roller. The gap between the cutter roller and the pressure roller is 23 μm, and the chopped fiber bundle is controlled at 25℃ to obtain a chopped fiber bundle with a length of 12 mm. A high-pressure ion nozzle is installed at the outlet of the chopped fiber device, with a distance of 15 cm between the ion nozzle and the chopped fiber bundle. The obtained chopped fiber bundle is then destaticated to obtain destatic fiber.

[0065] Flexible collection and screening: The destatic fibers are collected using a flexible conveyor belt. The speed of the conveyor belt is consistent with the output speed of the destatic fibers. The collected destatic fibers are sent to a 5-stage vibrating screen for screening to remove fibers and impurities that are not up to standard in length, thus obtaining basalt short-cut fibers.

[0066] Comparative Example 1 Basalt precursor yarns with a diameter of 11 μm were unwound under constant tension (without fixed tension) to obtain a continuous fiber bundle. The obtained continuous fiber bundle was then chopped using a high-speed cutter roller with a linear speed of 50 m / min to obtain chopped fiber bundles with a length of 6 mm. The chopped fiber bundles were then sieved to obtain basalt chopped fibers.

[0067] Test Example 1 The bundle rate and filament rate of basalt chopped fibers obtained in Examples 1-3 and Comparative Example 1 were tested. Referring to the relevant testing specifications of JC / T 896-2017 and GB / T 18369-2022, the bundle rate of basalt chopped fibers was determined by sieving and sorting, and the filament rate was determined by separating loose and broken fibers by air classification. The samples were dried, graded and screened and accurately weighed under standard temperature and humidity conditions. The proportions of the two indicators were calculated to evaluate the uniformity of chopped fiber dispersion and the quality of the finished product.

[0068] The basalt chopped fibers obtained in Examples 1-3 and Comparative Example 1 were added to the fireproof board in the same amount. The fiber pull-out force, flexural strength, and impact toughness of the resulting basalt fiber fireproof board were tested. The fiber pull-out force between the basalt fiber and the matrix was determined according to ISO 19375:2024. The flexural strength of the sample was tested by a three-point bending test according to GB / T 17671-2021 and JC / T 2558-2019, and mechanical calculations were completed. A simply supported beam impact test was carried out according to GB / T 1451-2005 to determine the impact absorption energy of the board and convert it into impact toughness. The interfacial bonding performance, flexural mechanical properties, and impact and crack resistance of the board were comprehensively evaluated.

[0069] Basalt fiber fireproof boards were prepared using the following raw materials, with a water-to-raw material mass ratio of 0.3:1. The raw materials, by mass parts, included: 48 parts silicate cement, 15 parts fly ash, 20 parts aluminum hydroxide, 15 parts chopped basalt fibers, 1 part aramid fiber, 0.5 parts polycarboxylate dispersant, and 1 part organosilicon waterproofing agent. The chopped basalt fibers were those obtained in Examples 1-3 and Comparative Example 1. The preparation method is as follows: Silicate cement, fly ash, aluminum hydroxide, polycarboxylate dispersant, and organosilicon waterproofing agent are mixed to obtain a dry mixture; aramid fiber and polycarboxylate dispersant are stirred and dispersed in water for 10 minutes to obtain a fiber dispersion; the obtained dry mixture and fiber dispersion are stirred and mixed for 15 minutes to obtain a mixed slurry; the obtained mixed slurry is injected into a mold and formed by vacuum vibration filtration or molding at a pressure of 1.2 MPa for 10 minutes; after demolding the obtained molded board, it is cured in an environment with a temperature of 80℃ and a humidity of ≥90% for 48 hours. The cured board is dried at 100℃ until the moisture content is ≤5%, and cut into sizes of 1200mm×600mm×12mm to obtain a basalt fiber fireproof board.

[0070] The test results are shown in Table 1.

[0071] Table 1. Performance test results of basalt chopped fibers and basalt fiber fireproof boards prepared in Examples 1-3 and Comparative Example 1.

[0072] Compared with Comparative Example 1, the advantages of the basalt short-cut fibers and the basalt fiber fireproof boards prepared in Examples 1-3 are as follows: (1) Improved dispersion performance: The bundle ratio of basalt short-cut fibers obtained in Examples 1-3 is only 6.9-7.8% and the filament ratio is only 3.2-3.9%, which is significantly lower than that of Comparative Example 1 (bundle ratio 18.6% and filament ratio 12.3%). The core reason is that the present invention adopts a three-step synergistic improvement of airflow pre-opening, online electrostatic elimination, and low-temperature gentle cutting. Airflow pre-opening disperses the fiber bundle in advance and breaks the monofilament cohesion state; online electrostatic elimination neutralizes the static electricity generated by friction and avoids fiber adsorption and agglomeration; low-temperature gentle cutting avoids high-temperature melting and adhesion and ensures that the fiber is in a monofilament state. The three work together to achieve a significant improvement in the dispersion performance of basalt short-cut fibers.

[0073] (2) Improved interfacial bonding performance: The fiber pull-out force of the basalt short-cut fibers obtained in Examples 1-3 was increased to 17.5-19.1 mN, which is 36.7-49.2% higher than that of Comparative Example 1 (12.8 mN). This is because the present invention uses low-temperature gentle cutting to ensure that the fiber end face is flat and neat without splitting burrs, increasing the contact area with the matrix and effectively solving the technical problem of weak interfacial bonding in conventional processes.

[0074] (3) Improved performance of fireproof boards: The basalt fiber fireproof boards made from basalt short-cut fibers obtained in Examples 1-3 have a flexural strength of 11.2-12.3 MPa and an impact toughness of 16.1-17.4 kJ / m. 2 Compared with Comparative Example 1, the basalt short-cut fibers obtained in Examples 1-3 were increased by 30.2-43.0% and 28.8-39.2% respectively. The basalt short-cut fibers were uniformly dispersed in the basalt fiber fireproof board, which avoided stress concentration inside the basalt fiber fireproof board. The interface between the basalt short-cut fibers and the matrix was firmly bonded, ensuring that it would not debond at high temperature. The reinforcing effect of the basalt short-cut fibers was fully utilized, and the flexural strength and impact toughness of the basalt fiber fireproof board were improved.

[0075] Example 4 Basalt fiber fireproof board was prepared using the following raw materials, with a water-to-raw material mass ratio of 0.3:1. The raw materials, by mass parts, included: The mixture contains 48 parts sulfoaluminate cement, 10 parts fly ash, 20 parts expanded perlite, 5 parts silica fume, 12 parts basalt chopped fibers, 2 parts polyvinyl alcohol fibers, 0.5 parts polycarboxylate dispersant, and 1 part organosilicon waterproofing agent. The basalt chopped fibers are those prepared in Example 1, with a length of 6 mm.

[0076] The preparation method is as follows: Sulfoaluminate cement, fly ash, expanded perlite, silica fume, polycarboxylate dispersant, and organosilicon waterproofing agent were mixed to obtain a dry mixture. Polyvinyl alcohol fiber and polycarboxylate dispersant were stirred and dispersed in water for 10 minutes to obtain a fiber dispersion. The dry mixture and fiber dispersion were stirred and mixed for 15 minutes to obtain a mixed slurry. The mixed slurry was injected into a mold and vacuum vibrated and filtered to form a slurry at a pressure of 1.2 MPa for 10 minutes. After demolding the resulting slab, it was cured in an environment with a temperature of 80℃ and a humidity of ≥90% for 48 hours. The cured slab was dried at 100℃ until the moisture content was ≤5%, and then cut into 1200mm×600mm×12mm sizes to obtain basalt fiber fireproof board.

[0077] The density of the basalt fiber fireproof board prepared in Example 4 was tested and found to be 980 kg / m³. 3 With a flexural strength ≥18MPa, thermal conductivity 0.075W / (m·K), no flame or dripping during combustion test, and a mass loss rate <50%, it is classified as an A1 grade non-combustible material with a fire resistance limit of 150min.

[0078] Example 5 Basalt fiber fireproof board was prepared using the following raw materials, with a water-to-raw material mass ratio of 0.3:1. The raw materials, by mass parts, included: The mixture contains 40 parts silicate cement, 15 parts fly ash, 25 parts aluminum hydroxide, 15 parts basalt chopped fibers, 1 part aramid fiber, 0.5 parts polycarboxylate dispersant, and 1 part organosilicon waterproofing agent. The basalt chopped fibers are those prepared in Example 2, with a length of 3 mm.

[0079] The preparation method is as follows: Silicate cement, fly ash, aluminum hydroxide, polycarboxylate dispersant, and organosilicon waterproofing agent are mixed to obtain a dry mixture. Aramid fibers and polycarboxylate dispersant are stirred and dispersed in water for 10 minutes to obtain a fiber dispersion. The obtained dry mixture and fiber dispersion are stirred and mixed for 15 minutes to obtain a mixed slurry. The obtained mixed slurry is injected into a mold and formed by vacuum vibration filtration or molding at a pressure of 1.2 MPa for 10 minutes. After demolding the obtained molded board, it is cured in an environment with a temperature of 80℃ and a humidity of ≥90% for 48 hours. The cured board is dried at 100℃ until the moisture content is ≤5%, and then cut into 1200mm×600mm×12mm sizes to obtain basalt fiber fireproof board.

[0080] Testing showed that the basalt fiber fireproof board prepared in Example 5 had a fire resistance limit of 130 minutes and a smoke index of less than 10, demonstrating excellent environmental performance.

[0081] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method of producing basalt chopped fibers, characterized by, Includes the following steps: The basalt fiber is unwound to obtain a continuous fiber bundle; The continuous fiber bundle is pre-opened by airflow to obtain a fluffy continuous fiber bundle; The fluffy continuous fiber bundle is chopped to obtain a chopped fiber bundle; the chopping temperature is ≤35℃, and the linear speed of the cutting roller is 15~20m / min. The chopped fiber bundles are destaticated to obtain the basalt chopped fibers.

2. The production method according to claim 1, characterized by, The unwinding process includes using a three-stage tension roller group for unwinding; the tension of each stage of the tension roller group decreases progressively, and the tension difference between two adjacent stages of the tension roller group is ≤5N.

3. The preparation method according to claim 1, characterized in that, The airflow velocity for pre-opening is 5~8m / s, and the angle between the airflow direction and the conveying direction of the continuous fiber bundle is 30~45°.

4. The method of claim 1, wherein, The static electricity removal includes static electricity removal using high-voltage ion air. The output voltage of the high-pressure ion wind is 4.5~5.5kV, the working frequency is 50~60Hz, and the current of a single ion rod is 0.2~0.3mA / m; The air source of the high-pressure ion wind includes air, the working air pressure is 0.3-0.5 MPa, the fiber surface wind speed is 8-12 m / s, and the air volume is 0.25-0.4 m 3 / (min·m).

5. The basalt chopped strand fiber produced by the production process according to any one of claims 1 to 4, characterized in that The basalt short-cut fibers have a length of 3-8 mm, a bundle rate of 6.9-7.8%, and a filament rate of 3.2-3.9%.

6. A basalt fiber fire rated panel, characterized by, By weight, it includes 8-15 parts of basalt chopped fiber, 40-55 parts of cement-fly ash composite cementitious material, 20-30 parts of inorganic functional filler, 1-3 parts of reinforcing fiber, 0.3-0.8 parts of dispersant and 0.5-1.5 parts of waterproofing agent; The basalt short-cut fiber is the basalt short-cut fiber as described in claim 5.

7. The basalt fiber fireboard of claim 6, wherein, The cement in the cement-fly ash composite cementitious material includes sulfoaluminate cement and / or silicate cement. The mass percentage of fly ash in the cement-fly ash composite cementitious material is 15-30%; The inorganic functional filler includes one or more of expanded perlite, silica fume and aluminum hydroxide; The reinforcing fibers include polyvinyl alcohol fibers and / or aramid fibers; The dispersant includes polycarboxylic acid dispersants; The waterproofing agent includes an organosilicon waterproofing agent.

8. The method of manufacturing basalt fiber fireproof panel according to claim 6 or 7, characterized in that, Includes the following steps: A dry mix is ​​obtained by mixing cement-fly ash composite cementitious material, inorganic functional filler, dispersant and waterproofing agent; Basalt short-cut fibers and reinforcing fibers were dispersed in water to obtain a fiber dispersion. The dry mixture and the fiber dispersion are mixed to obtain a mixed slurry; The mixed slurry is molded and then cured to obtain basalt fiber fireproof board.

9. The production method according to claim 8, characterized by, The molding process includes vacuum vibration pressure filtration molding; The pressure for vacuum vibration filtration molding is 0.8~1.5MPa, and the time is 5~10min; The curing temperature is 60~80℃, the humidity is ≥90%, and the time is 24~48h.

10. The application of the basalt fiber fireproof board according to any one of claims 6 to 7 or the basalt fiber fireproof board prepared by the preparation method according to any one of claims 8 to 9 in the interior and exterior walls of buildings, subway tunnels or ship bulkheads.

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