A method of manufacturing basalt fiber composite and its use in flame retardant fabric
By modifying basalt fibers with aluminate and grafting carboxyl-functionalized boron nitride and titanium dioxide, and bridging with a polyamino coupling agent, the interfacial compatibility problem between basalt fibers and the polymer matrix is solved, resulting in basalt fiber composite materials with high flame retardancy, excellent mechanical properties and good textile processing performance, thus improving the flame retardancy and ablation resistance of fabrics.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CHENGDU TEXTILE COLLEGE
- Filing Date
- 2026-04-03
- Publication Date
- 2026-06-09
AI Technical Summary
The existing basalt fiber has poor interfacial compatibility with the polymer matrix, which easily leads to weak interfacial adhesion, limited improvement in mechanical properties, and a tendency to produce a 'wick effect' during combustion. The flame retardant is unevenly dispersed, making it difficult to achieve a balance between high-efficiency flame retardancy and excellent mechanical properties. Furthermore, the fabric's flexibility and textile processing performance are insufficient.
Basalt fibers were modified with aluminate coupling agents, grafted with carboxyl-functionalized boron nitride and titanium dioxide, and multi-scale covalently bonded interface structures were formed using polyamino coupling agents. The interface compatibility and mechanical properties were improved by bridging with a self-made polyaminoaluminate-siloxane hybrid coupling agent.
Significantly improves the flame retardant and mechanical properties of basalt fiber composites, forms a dense ceramic barrier layer, increases the limiting oxygen index and reduces the peak heat release rate, and enhances the flame retardant and ablation resistance of the fabric.
Smart Images
Figure SMS_1
Abstract
Description
Technical Field
[0001] This invention belongs to the field of inorganic non-metallic reinforcing materials technology. More specifically, this invention relates to a method for preparing basalt fiber composite materials and their application in flame-retardant fabrics. Background Technology
[0002] Basalt fiber is a high-performance inorganic non-metallic fiber made from natural basalt ore through high-temperature melting and fiber drawing processes. It has excellent properties such as high strength, high heat resistance, flame retardancy, heat insulation, and environmental friendliness. It is an ideal reinforcement for the preparation of flame-retardant composite materials and has broad application prospects in fields such as fire emergency response, safety protection, and aerospace.
[0003] Currently, the technology of blending basalt fiber with polymer materials to prepare composite materials and applying them to flame-retardant fabrics has attracted widespread attention. However, existing technologies still face many bottlenecks that urgently need to be addressed: First, the surface of basalt fiber is highly inert and has poor interfacial compatibility with the polymer matrix, which easily leads to defects such as weak interfacial adhesion and limited improvement in mechanical properties of the composite material. Moreover, during combustion, the polymer melt easily weeps and spreads along the surface of the basalt fiber, producing a "wick effect" that exacerbates the fire hazard. Second, existing flame-retardant modification methods often involve directly adding a large amount of flame-retardant filler, which significantly reduces the flexibility and comfort of the composite material. Furthermore, some flame retardants pose environmental risks and have low flame-retardant efficiency. Third, basalt fiber itself is highly brittle, and it is difficult to achieve both the required softness and toughness of the fabric after being combined with polymer materials. In addition, a single flame-retardant system cannot simultaneously achieve synergistic optimization of efficient flame retardancy, smoke suppression, and mechanical properties, failing to meet the stringent requirements of high-end flame-retardant fabrics (such as fire suits and aviation interior fabrics).
[0004] To address these issues, existing technologies attempt to improve the compatibility between basalt fibers and the matrix through surface modification or to optimize flame retardant performance through compounding with flame retardants. For example, some methods treat the surface of basalt fibers with silane coupling agents, but this only slightly improves interfacial bonding and cannot suppress the "wick effect." Other methods blend halogen-free flame retardants with basalt fibers and polymer matrices, but still suffer from uneven dispersion of the flame retardant and poor synergy with the fiber, making it difficult to achieve a balance between high flame retardancy and excellent mechanical properties at low addition levels. Furthermore, existing preparation methods often focus on optimizing the mechanical reinforcement or a single flame retardant performance index of the composite material, neglecting the specific requirements of fabric applications for material flexibility, spinning stability, and washability. This results in composite materials that are difficult to process into fabrics using conventional textile processes, or fabrics whose flame retardant properties easily degrade.
[0005] Therefore, developing a preparation method that can simultaneously solve problems such as poor compatibility between basalt fiber and polymer matrix, "candle wick effect," contradiction between flame retardancy and mechanical properties, and insufficient weaving adaptability, and through innovative modification and composite processes, enables basalt fiber composite materials to possess both high-efficiency flame retardancy, excellent mechanical properties, and good textile processing performance, has become an urgent need for the application of basalt fiber in the field of flame-retardant fabrics. This is of great significance for promoting the upgrading of the flame-retardant fabric industry and expanding the high-end application scenarios of basalt fiber. Summary of the Invention
[0006] One object of the present invention is to solve at least the above-mentioned problems and / or defects, and to provide at least the advantages described below.
[0007] To achieve these and other advantages according to the present invention, the present invention provides a method for preparing a basalt fiber composite material, comprising the following steps: Step 1: Modify basalt fibers using aluminate coupling agents to obtain coupling agent-modified basalt fibers; Step 2: Graft carboxyl-functionalized boron nitride onto the surface of coupling agent-modified basalt fibers to obtain boron nitride-grafted modified basalt fibers. Step 3: Use a polyamino coupling agent to graft carboxyl-functionalized titanium dioxide onto boron nitride-grafted modified basalt fibers, and dry to obtain basalt fiber composite material.
[0008] Preferably, in step one, the specific method for modifying basalt fibers using an aluminate coupling agent includes: S11. Basalt fibers are immersed in a 2wt%~5wt% NaOH solution, stirred and heated to 70℃~80℃, kept at this temperature for 15min~40min, washed and vacuum dried to obtain alkaline-etched basalt fibers; wherein, the ratio of basalt fibers to NaOH solution is 1g~20g:100mL~250mL; S12. Add aluminate DL-411 to an ethanol / water mixed solvent, heat to 40℃~80℃, add alkali-etched basalt fiber, stir at 200rpm~500rpm for 1h~4h, cool to room temperature and separate solid and liquid, wash several times, and vacuum dry at 60℃~80℃ for 6h~12h to obtain coupling agent modified basalt fiber; wherein, the ratio of aluminate DL-411, ethanol / water mixed solvent and alkali-etched basalt fiber is 5g~8g:300mL~600mL:1g~50g.
[0009] Preferably, in step two, the specific method for grafting carboxyl-functionalized boron nitride onto the surface of coupling agent-modified basalt fibers includes: S21. Carboxyl-functionalized boron nitride is ultrasonically dispersed in N,N-dimethylformamide, N,N'-dicyclohexylcarbodiimide is added, and the mixture is stirred at room temperature for 10 min to 30 min to obtain an activated boron nitride dispersion. S22. Under a nitrogen atmosphere, alkali-etched basalt fibers are added to an activated boron nitride dispersion, heated in a water bath at 60℃~70℃, and stirred at 400rpm~800rpm for 2h~6h. After solid-liquid separation, the fibers are washed multiple times and then vacuum dried at 70℃~80℃ for 6h~12h to obtain boron nitride grafted modified basalt fibers.
[0010] Preferably, in step S21, the ratio of carboxyl-functionalized boron nitride, N,N-dimethylformamide, and N,N'-dicyclohexylcarbodiimide is 8g~12g:100mL~400mL:1g~10g. In S22, the ratio of alkali-etched basalt fibers to activated boron nitride dispersion is 1g~50g:100mL~400mL.
[0011] Preferably, in step three, the specific method for grafting carboxyl-functionalized titanium dioxide onto boron nitride-grafted modified basalt fibers using a polyamino coupling agent includes: S31. Add the polyamino coupling agent to a mixed solvent of ethanol / N,N-dimethylformamide and stir at room temperature for 10 min to 30 min to obtain a coupling agent solution. S32. Add carboxyl-functionalized titanium dioxide to the coupling agent solution and disperse it by ultrasonication to obtain a composite dispersion. Add boron nitride-grafted modified basalt fiber to the composite dispersion, heat it in a water bath to 60℃~80℃, and stir it at 500rpm for 2h~4h. Take out the fiber, wash it several times with anhydrous ethanol, and vacuum dry it at 60℃~80℃ for 6h~12h to obtain the basalt fiber composite material.
[0012] Preferably, in step S31, the ratio of the polyamino coupling agent to the ethanol / N,N-dimethylformamide mixed solvent is 1g~10g:100mL~400mL. In S32, the ratio of carboxyl-functionalized titanium dioxide, coupling agent solution, and boron nitride grafted modified basalt fiber is 10g~20g:100mL~400mL:1g~50g.
[0013] Preferably, in step three, the preparation method of the polyamino coupling agent includes: Step A: Dissolve aluminum isopropoxide in anhydrous ethanol, add citric acid and glacial acetic acid, heat to 60℃~70℃, turn on reflux, and reflux at a constant temperature for 2h~5h to obtain aluminum citrate chelate solution. Step B: Add coupling agent KH-792 dropwise to the aluminate citrate chelate solution. During the dropwise addition, maintain the system temperature at 60℃~70℃ and the stirring speed at 200rpm~300rpm. After the dropwise addition is complete, add deionized water to the system, and then raise the system temperature to 70℃~80℃. Keep the stirring speed constant and react at this temperature for 3~4 hours to obtain the polyaminoaluminate-siloxane hybrid reaction solution. Step C: Distill the polyaminoaluminate-siloxane hybrid reaction solution under reduced pressure at 60℃~90℃ and a vacuum of -0.09MPa for 10min~30min, and dry the crude product under vacuum at 60℃~80℃ for 2h~6h to obtain the polyamino coupling agent.
[0014] Preferably, in step A, the ratio of aluminum isopropoxide, anhydrous ethanol, citric acid, and glacial acetic acid is 1 mol~2 mol: 3 mol~5 mol: 0.5 mol~1 mol: 10 mL~20 mL. In step B, the ratio of coupling agent KH-792 to aluminate citrate chelate solution is 1g~20g:100mL~200mL.
[0015] A basalt fiber composite material, wherein the basalt fiber composite material is prepared by the above-mentioned method for preparing basalt fiber composite materials.
[0016] An application of a basalt fiber composite material, wherein the basalt fiber composite material is used to prepare flame-retardant fabrics.
[0017] The present invention has at least the following beneficial effects: The present invention obtains a basalt fiber composite material with double-layer flame retardant properties by sequentially grafting carboxyl-functionalized boron nitride and carboxyl-functionalized titanium dioxide onto the surface of basalt fibers. The prepared basalt fiber composite material has excellent flame retardant and mechanical properties and can be used as a high-quality raw material for preparing flame retardant fabrics.
[0018] This invention first modifies the surface of basalt fibers using aluminate DL-411, significantly increasing the number of active sites on the basalt fiber surface. Then, carboxyl-functionalized boron nitride is covalently grafted onto the basalt fibers. Finally, a self-made polyaminoaluminate-siloxane hybrid coupling agent is used as a "molecular bridge" to stably graft carboxyl-functionalized titanium dioxide onto the boron nitride layer, forming a multi-scale, strongly covalently bonded interface structure of basalt fiber-aluminate-BN-TiO2. This method significantly reduces interfacial defects between basalt fibers and boron nitride, and between boron nitride and titanium dioxide, greatly improving stress transfer efficiency. The resulting broken basalt fiber composite material exhibits significantly better tensile strength, interfacial shear strength, and elongation at break than single-modified or unmodified systems. Furthermore, blending the basalt fiber composite material with polymer systems such as polylactic acid to prepare composite flame-retardant fabrics significantly improves the mechanical properties of the composite flame-retardant fabrics.
[0019] The basalt fiber composite material prepared by this invention exhibits excellent flame retardant and heat resistance properties, with a high limiting oxygen index and a low heat release rate. Boron nitride (BN) possesses excellent barrier properties, thermal stability, and insulation, while titanium dioxide (TiO2) catalyzes char formation, inhibits dripping, and dilutes combustible gases. When the basalt composite material prepared by this invention is combined with polylactic acid to create a composite flame-retardant fabric, the synergistic flame retardancy of BN and TiO2 results in a dense and continuous ceramicized barrier layer formed by the basalt fiber composite material during combustion. This effectively blocks the transfer of heat, oxygen, and combustible gases, significantly improving the limiting oxygen index (LOI) and UL94 flame retardant rating of the composite flame-retardant fabric, and significantly reducing the peak heat release rate (PHRR). The flame retardant and ablation resistance properties are far superior to systems modified with only a single filler.
[0020] The self-made polyamino coupling agent of this invention achieves precise bridging between carboxylated titanium dioxide and carboxylated boron nitride. The polyamino coupling agent uses citric acid chelated aluminum isopropoxide as the core and is modified by KH-792 polyamino siloxane. The molecular structure contains both aluminate chelating groups and polyamino groups. Among them, the aluminate chelating groups strongly bind to the siloxane structure of basalt fiber, improving the compatibility between carboxylated functionalized titanium dioxide and carboxylated functionalized boron nitride. The polyamino groups bond with carboxylated functionalized boron nitride and carboxylated functionalized titanium dioxide, improving the interlayer bonding strength between carboxylated functionalized carbon dioxide and carboxylated functionalized boron nitride. This solves the problems of single binding sites and poor reactivity with carboxylated fillers in traditional coupling agents, making carboxylated TiO2 and carboxylated boron nitride uniformly dispersed on the surface of basalt fiber and not easy to fall off.
[0021] Other advantages, objectives and features of the present invention will become apparent in part from the following description, and in part from those skilled in the art through study and practice of the invention. Detailed Implementation
[0022] The present invention will now be described in further detail so that those skilled in the art can implement it based on the description.
[0023] It should be understood that terms such as “having,” “comprising,” and “including” as used herein do not exclude the presence or addition of one or more other elements or combinations thereof. The methods for preparing carboxyl-functionalized boron nitride used in the various embodiments and comparative examples include: Under ice-water bath conditions, 100 mL of 12 mol / L sulfuric acid and 50 mL of 10 mol / L nitric acid were added dropwise to a beaker containing 10 g of boron nitride. The temperature was raised to 80 °C and the mixture was magnetically stirred at 400 rpm for 12 h. The reaction solution was cooled to room temperature, diluted in 200 mL of deionized water, and the pH was adjusted to 7 with NaOH solution. The supernatant was discarded by centrifugation, and the precipitate was washed several times and dried under vacuum at 60 °C for 8 h. The precipitate was then ground into powder to obtain carboxyl-functionalized boron nitride.
[0024] The preparation method of carboxyl-functionalized titanium dioxide used in each embodiment and comparative example includes: under ice-water bath conditions, slowly add 120 mL of 12 mol / L sulfuric acid and 40 mL of 10 mL / L nitric acid to a beaker containing 15 g of titanium dioxide, then heat to 75 °C and magnetically stir the reaction for 8 h. The reaction solution was cooled to room temperature, diluted in 250 mL of deionized water, and the pH was adjusted to 7 with NaOH solution. After centrifugation, the supernatant was discarded, and after washing several times, the precipitate was placed in a vacuum drying oven at 60 °C for 10 h and then ground to obtain carboxyl-functionalized titanium dioxide.
[0025] Example 1 A method for preparing a basalt fiber composite material includes the following steps: Step 1: Modify basalt fibers using aluminate coupling agents, specifically including: S11. 20g of basalt fiber powder was impregnated in 250mL of 5wt% NaOH solution, stirred and heated to 80℃, kept at the temperature for 30min, washed and vacuum dried to obtain alkali-etched basalt fiber. S12. Add 5g of aluminate DL-411 to 300mL of ethanol / water mixed solvent (ethanol to water volume ratio of 1:2), heat to 60℃, add 20g of alkali-etched basalt fiber, stir at 300rpm for 2h, cool to room temperature and then separate the solid and liquid. After washing several times, vacuum dry at 60℃ for 8h to obtain coupling agent modified basalt fiber.
[0026] Step 2: Grafting carboxyl-functionalized boron nitride onto the surface of coupling agent-modified basalt fibers, specifically including: S21. 10g of carboxyl-functionalized boron nitride was ultrasonically dispersed in 200mL of N,N-dimethylformamide, and 1.5g of N,N'-dicyclohexylcarbodiimide was added. The mixture was stirred at room temperature for 30min to obtain an activated boron nitride dispersion. S22. Under a nitrogen atmosphere, 50g of alkali-etched basalt fiber was added to 400mL of activated boron nitride dispersion, heated in a water bath at 60℃, stirred at 400rpm for 6h, and after solid-liquid separation, washed several times and dried under vacuum at 60℃ for 12h to obtain boron nitride grafted modified basalt fiber.
[0027] Step 3: Grafting carboxyl-functionalized titanium dioxide onto boron nitride-grafted basalt fibers using a polyamino coupling agent, specifically including: S31. Add 5g of polyamino coupling agent to 400mL of ethanol / N,N-dimethylformamide mixed solvent (the volume ratio of ethanol to N,N-dimethylformamide is 1:3), stir at room temperature for 30min to obtain the coupling agent solution. S32. Add 20g of carboxyl-functionalized titanium dioxide to 400mL of coupling agent solution and disperse it by ultrasonication to obtain a composite dispersion. Add 30g of boron nitride-grafted modified basalt fiber to the composite dispersion, heat it in a water bath to 80℃, and stir it at 500rpm for 3h. Take out the fiber, wash it several times with anhydrous ethanol, and vacuum dry it at 60℃ for 12h to obtain the basalt fiber composite material.
[0028] The preparation method of the polyamino coupling agent used in S31 includes: Step A: Dissolve 1 mol aluminum isopropoxide in 3 mol anhydrous ethanol, add 0.5 mol citric acid and 20 mL glacial acetic acid, heat to 65°C, turn on reflux, and reflux at a constant temperature for 5 h to obtain aluminate citrate chelate solution. Step B: Add 10g of coupling agent KH-792 dropwise to 200mL of aluminate citrate chelating solution. During the dropwise addition, maintain the system temperature at 6℃ and the stirring speed at 300rpm. After the dropwise addition is complete, add 200mL of deionized water to the system. Then, raise the system temperature to 80℃ and keep the stirring speed constant. React at this temperature for 3h to obtain the polyaminoaluminate-siloxane hybrid reaction solution. Step C: Distill the polyaminoaluminate-siloxane hybrid reaction solution under reduced pressure at 90°C and -0.09MPa for 30 min, and dry the crude product under vacuum at 60°C for 6 h to obtain the polyamino coupling agent.
[0029] Example 2 A method for preparing a basalt fiber composite material includes the following steps: Step 1: Modify basalt fibers using aluminate coupling agents, specifically including: S11. 20g of basalt fiber powder was impregnated in 250mL of 5wt% NaOH solution, stirred and heated to 80℃, kept at the temperature for 30min, washed and vacuum dried to obtain alkali-etched basalt fiber. S12. Add 5g of aluminate DL-411 to 300mL of ethanol / water mixed solvent (ethanol to water volume ratio of 1:2), heat to 60℃, add 20g of alkali-etched basalt fiber, stir at 300rpm for 2h, cool to room temperature and then separate the solid and liquid. After washing several times, vacuum dry at 60℃ for 8h to obtain coupling agent modified basalt fiber.
[0030] Step 2: Grafting carboxyl-functionalized boron nitride onto the surface of coupling agent-modified basalt fibers, specifically including: S21. 12g of carboxyl-functionalized boron nitride was ultrasonically dispersed in 200mL of N,N-dimethylformamide, and 2g of N,N'-dicyclohexylcarbodiimide was added. The mixture was stirred at room temperature for 30min to obtain an activated boron nitride dispersion. S22. Under a nitrogen atmosphere, 50g of alkali-etched basalt fiber was added to 400mL of activated boron nitride dispersion, heated in a water bath at 60℃, stirred at 400rpm for 6h, and after solid-liquid separation, washed several times and dried under vacuum at 60℃ for 12h to obtain boron nitride grafted modified basalt fiber.
[0031] Step 3: Grafting carboxyl-functionalized titanium dioxide onto boron nitride-grafted basalt fibers using a polyamino coupling agent, specifically including: S31. Add 5g of polyamino coupling agent to 400mL of ethanol / N,N-dimethylformamide mixed solvent (the volume ratio of ethanol to N,N-dimethylformamide is 1:3), stir at room temperature for 30min to obtain the coupling agent solution. S32. Add 15g of carboxyl-functionalized titanium dioxide to 300mL of coupling agent solution and disperse it by ultrasonication to obtain a composite dispersion. Add 30g of boron nitride-grafted modified basalt fiber to the composite dispersion, heat it in a water bath to 80℃, and stir it at 500rpm for 3h. Take out the fiber, wash it several times with anhydrous ethanol, and vacuum dry it at 60℃ for 12h to obtain the basalt fiber composite material.
[0032] The preparation method of the polyamino coupling agent used in Example S31 is the same as that in Example 1.
[0033] Example 3 A method for preparing a basalt fiber composite material includes the following steps: Step 1: Modify basalt fibers using aluminate coupling agents, specifically including: S11. 20g of basalt fiber powder was impregnated in 250mL of 5wt% NaOH solution, stirred and heated to 80℃, kept at the temperature for 30min, washed and vacuum dried to obtain alkali-etched basalt fiber. S12. Add 5g of aluminate DL-411 to 300mL of ethanol / water mixed solvent (ethanol to water volume ratio of 1:2), heat to 60℃, add 20g of alkali-etched basalt fiber, stir at 300rpm for 2h, cool to room temperature and then separate the solid and liquid. After washing several times, vacuum dry at 60℃ for 8h to obtain coupling agent modified basalt fiber.
[0034] Step 2: Prepare carboxyl-functionalized boron nitride and graft the carboxyl-functionalized boron nitride onto the surface of coupling agent-modified basalt fibers, specifically including: S21. Disperse 8g of carboxyl-functionalized boron nitride ultrasonically in 150mL of N,N-dimethylformamide, add 1g of N,N'-dicyclohexylcarbodiimide, stir at room temperature for 30min to obtain an activated boron nitride dispersion. S22. Under a nitrogen atmosphere, 50g of alkali-etched basalt fiber was added to 400mL of activated boron nitride dispersion, heated in a water bath at 60℃, stirred at 400rpm for 6h, and after solid-liquid separation, washed several times and dried under vacuum at 60℃ for 12h to obtain boron nitride grafted modified basalt fiber.
[0035] Step 3: Preparation of carboxyl-functionalized titanium dioxide. Carboxyl-functionalized titanium dioxide is grafted onto boron nitride-grafted basalt fibers using a polyamino coupling agent. Specifically, this includes: S31. Add 5g of polyamino coupling agent to 400mL of ethanol / N,N-dimethylformamide mixed solvent (the volume ratio of ethanol to N,N-dimethylformamide is 1:3), stir at room temperature for 30min to obtain the coupling agent solution. S32. Add 10g of carboxyl-functionalized titanium dioxide to 200mL of coupling agent solution and disperse it by ultrasonication to obtain a composite dispersion. Add 30g of boron nitride-grafted modified basalt fiber to the composite dispersion, heat it in a water bath to 80℃, and stir it at 500rpm for 3h. Take out the fiber, wash it several times with anhydrous ethanol, and vacuum dry it at 60℃ for 12h to obtain the basalt fiber composite material.
[0036] The preparation method of the polyamino coupling agent used in Example S31 is the same as that in Example 1.
[0037] Comparative Example 1 A method for preparing a boron nitride grafted modified basalt fiber composite material includes the following steps: Step 1: Modify basalt fibers using aluminate coupling agents, specifically including: S11. 20g of basalt fiber powder was impregnated in 250mL of 5wt% NaOH solution, stirred and heated to 80℃, kept at the temperature for 30min, washed and vacuum dried to obtain alkali-etched basalt fiber. S12. Add 5g of aluminate DL-411 to 300mL of ethanol / water mixed solvent (ethanol to water volume ratio of 1:2), heat to 60℃, add 20g of alkali-etched basalt fiber, stir at 300rpm for 2h, cool to room temperature and then separate the solid and liquid. After washing several times, vacuum dry at 60℃ for 8h to obtain coupling agent modified basalt fiber.
[0038] Step 2: Grafting carboxyl-functionalized boron nitride onto the surface of coupling agent-modified basalt fibers, specifically including: S21. 10g of carboxyl-functionalized boron nitride was ultrasonically dispersed in 200mL of N,N-dimethylformamide, and 1.5g of N,N'-dicyclohexylcarbodiimide was added. The mixture was stirred at room temperature for 30min to obtain an activated boron nitride dispersion. S22. Under a nitrogen atmosphere, 50g of alkali-etched basalt fiber was added to 400mL of activated boron nitride dispersion, heated in a water bath at 60℃, stirred at 400rpm for 6h, and after solid-liquid separation, washed several times and dried under vacuum at 60℃ for 12h to obtain boron nitride grafted modified basalt fiber.
[0039] Comparative Example 2 A method for preparing a titanium dioxide-grafted modified basalt fiber composite material includes the following steps: Step 1: Modify basalt fibers using aluminate coupling agents, specifically including: S11. 20g of basalt fiber powder was impregnated in 250mL of 5wt% NaOH solution, stirred and heated to 80℃, kept at the temperature for 30min, washed and vacuum dried to obtain alkali-etched basalt fiber. S12. Add 5g of aluminate DL-411 to 300mL of ethanol / water mixed solvent (ethanol to water volume ratio of 1:2), heat to 60℃, add 20g of alkali-etched basalt fiber, stir at 300rpm for 2h, cool to room temperature and then separate the solid and liquid. After washing several times, vacuum dry at 60℃ for 8h to obtain coupling agent modified basalt fiber.
[0040] Step 2: Grafting carboxyl-functionalized titanium dioxide onto the surface of coupling agent-modified basalt fibers using a polyamino coupling agent, specifically including: S21. Add 5g of polyamino coupling agent to 400mL of ethanol / N,N-dimethylformamide mixed solvent (the volume ratio of ethanol to N,N-dimethylformamide is 1:3), stir at room temperature for 30min to obtain the coupling agent solution. S22. Add 20g of carboxyl-functionalized titanium dioxide to 400mL of coupling agent solution and disperse it by ultrasonication to obtain a composite dispersion. Add 30g of coupling agent-modified basalt fiber to the composite dispersion, heat it in a water bath to 80℃, and stir it at 500rpm for 3h. Take out the fiber, wash it several times with anhydrous ethanol, and dry it under vacuum at 60℃ for 12h to obtain a titanium dioxide grafted basalt fiber composite material.
[0041] The preparation method of the polyamino coupling agent used in Example S21 is the same as that in Example 1.
[0042] Comparative Example 3 A method for preparing a basalt fiber composite material includes the following steps: Step 1: Modify basalt fibers using aluminate coupling agents, specifically including: S11. 20g of basalt fiber powder was impregnated in 250mL of 5wt% NaOH solution, stirred and heated to 80℃, kept at the temperature for 30min, washed and vacuum dried to obtain alkali-etched basalt fiber. S12. Add 5g of aluminate DL-411 to 300mL of ethanol / water mixed solvent (ethanol to water volume ratio of 1:2), heat to 60℃, add 20g of alkali-etched basalt fiber, stir at 300rpm for 2h, cool to room temperature and then separate the solid and liquid. After washing several times, vacuum dry at 60℃ for 8h to obtain coupling agent modified basalt fiber.
[0043] Step 2: Prepare carboxyl-functionalized boron nitride and graft the carboxyl-functionalized boron nitride onto the surface of coupling agent-modified basalt fibers, specifically including: S21. 10g of carboxyl-functionalized boron nitride was ultrasonically dispersed in 200mL of N,N-dimethylformamide, and 1.5g of N,N'-dicyclohexylcarbodiimide was added. The mixture was stirred at room temperature for 30min to obtain an activated boron nitride dispersion. S22. Under a nitrogen atmosphere, 50g of alkali-etched basalt fiber was added to 400mL of activated boron nitride dispersion, heated in a water bath at 60℃, stirred at 400rpm for 6h, and after solid-liquid separation, washed several times and dried under vacuum at 60℃ for 12h to obtain boron nitride grafted modified basalt fiber.
[0044] Step 3: Preparation of carboxyl-functionalized titanium dioxide. Carboxyl-functionalized titanium dioxide is grafted onto boron nitride-grafted basalt fibers using a polyamino coupling agent. Specifically, this includes: S31. Add 5g of coupling agent KH-792 to 400mL of ethanol / N,N-dimethylformamide mixed solvent (the volume ratio of ethanol to N,N-dimethylformamide is 1:3), stir at room temperature for 30min to obtain the coupling agent solution. S32. Add 20g of carboxyl-functionalized titanium dioxide to 400mL of coupling agent solution and disperse it by ultrasonication to obtain a composite dispersion. Add 30g of boron nitride-grafted modified basalt fiber to the composite dispersion, heat it in a water bath to 80℃, and stir it at 500rpm for 3h. Take out the fiber, wash it several times with anhydrous ethanol, and vacuum dry it at 60℃ for 12h to obtain the basalt fiber composite material.
[0045] Composite flame-retardant fabrics were prepared by blending basalt fiber composite materials prepared in Examples 1-3 and Comparative Examples 1-3, and unmodified basalt fiber raw materials with polylactic acid, respectively. The specific methods included: By weight, 85.5 parts of polylactic acid (PLA), 12 parts of basalt fiber composite material (prepared from Examples 1-3 and Comparative Examples 1-3, respectively) or basalt fiber raw material (unmodified), 2 parts of maleic anhydride-grafted polylactic acid (PLA-g-MAH) as compatibilizer, and 0.5 parts of antioxidant 1010 were mixed evenly and fed into a twin-screw extruder. The temperatures of each section of the twin-screw extruder were set to 165℃, 175℃, and 185℃, respectively, with the die head at 190℃ and the screw speed at 150 rpm. The mixture was then water-cooled and pelletized to obtain composite polylactic acid flame retardant masterbatch. Composite polylactic acid (PLA) flame-retardant masterbatch was melt-spun at an extrusion temperature of 190℃, a spinneret orifice diameter of 0.25mm, and a draw ratio of 3.5 to obtain composite PLA fiber filaments. These filaments were then twisted at 80T / m and heat-set at 120℃ for 5 minutes to obtain a PLA flame-retardant composite fabric. A blank control was prepared using pure PLA flame-retardant fabric prepared without the addition of basalt fiber.
[0046] The limiting oxygen index (LOI), UL94 flammability rating, peak heat release rate (PHRR), and mechanical properties of composite flame-retardant fabrics prepared from basalt fiber composite materials and basalt fiber raw materials in Examples 1-3 and Comparative Examples 1-3 were determined respectively. The limiting oxygen index (LOI) was tested according to GB / T 5454-1997, the UL94 rating according to GB / T2408-2022 (strip thickness 3.2 mm), the peak heat release rate (PHRR) according to ISO 5660, and the tensile strength and elongation at break according to GB / T 3923.1-2013. The results are shown in the table below: Table 1 Comparison of Flame Retardant and Mechanical Properties of Each Sample As can be seen from the table above, the composite flame-retardant fabric obtained after adding the basalt fiber composite materials prepared in Examples 1-3 exhibits superior flame-retardant and mechanical properties. This indicates that compared to the basalt fiber composite material with only a single layer of boron nitride and titanium dioxide, the double-layer flame-retardant structure of boron nitride and titanium dioxide significantly improves the flame-retardant and mechanical properties of the polylactic acid fabric system. At the same time, compared to the conventional silane coupling agent KH-792, the polyamino coupling agent prepared in this invention significantly improves the flame-retardant and mechanical properties of the polylactic acid fabric system.
[0047] The number of devices and processing scale described herein are for the purpose of simplifying the description of the invention. Applications, modifications, and variations of the invention will be readily apparent to those skilled in the art.
[0048] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details and examples shown and described herein.
Claims
1. A method for preparing a basalt fiber composite material, characterized in that, Includes the following steps: Step 1: Modify basalt fibers using aluminate coupling agents to obtain coupling agent-modified basalt fibers; Step 2: Graft carboxyl-functionalized boron nitride onto the surface of coupling agent-modified basalt fibers to obtain boron nitride-grafted modified basalt fibers. Step 3: Use a polyamino coupling agent to graft carboxyl-functionalized titanium dioxide onto boron nitride-grafted modified basalt fibers, and dry to obtain basalt fiber composite material.
2. The method for preparing basalt fiber composite material as described in claim 1, characterized in that, The specific method of step one includes: immersing basalt fibers in NaOH solution, stirring and heating to react, washing and vacuum drying to obtain alkali-etched basalt fibers; adding aluminate DL-411 to an ethanol / water mixed solvent, heating and adding alkali-etched basalt fibers, reacting and cooling to room temperature to separate solid and liquid, washing multiple times, and vacuum drying to obtain coupling agent modified basalt fibers.
3. The method for preparing basalt fiber composite material as described in claim 1, characterized in that, The specific method for step two includes: S21. Carboxyl-functionalized boron nitride is ultrasonically dispersed in N,N-dimethylformamide, N,N'-dicyclohexylcarbodiimide is added, and the mixture is stirred at room temperature for 10 min to 30 min to obtain an activated boron nitride dispersion. S22. Under a nitrogen atmosphere, alkali-etched basalt fibers are added to an activated boron nitride dispersion, heated in a water bath at 60℃~70℃, and stirred at 400rpm~800rpm for 2h~6h. After solid-liquid separation, the fibers are washed multiple times and then vacuum dried at 70℃~80℃ for 6h~12h to obtain boron nitride grafted modified basalt fibers.
4. The method for preparing basalt fiber composite material as described in claim 3, characterized in that, In S21, the ratio of carboxyl-functionalized boron nitride, N,N-dimethylformamide, and N,N'-dicyclohexylcarbodiimide is 8g~12g:100mL~400mL:1g~10g; In S22, the ratio of alkali-etched basalt fibers to activated boron nitride dispersion is 1g~50g:100mL~400mL.
5. The method for preparing basalt fiber composite material as described in claim 1, characterized in that, The specific methods for step three include: S31. Add the polyamino coupling agent to a mixed solvent of ethanol / N,N-dimethylformamide and stir at room temperature for 10 min to 30 min to obtain a coupling agent solution. S32. Add carboxyl-functionalized titanium dioxide to the coupling agent solution and disperse it by ultrasonication to obtain a composite dispersion. Add boron nitride-grafted modified basalt fiber to the composite dispersion, heat it in a water bath to 60℃~80℃, and stir it at 500rpm for 2h~4h. Take out the fiber, wash it several times with anhydrous ethanol, and vacuum dry it at 60℃~80℃ for 6h~12h to obtain the basalt fiber composite material.
6. The method for preparing the basalt fiber composite material as described in claim 5, characterized in that, In S31, the ratio of polyamino coupling agent to ethanol / N,N-dimethylformamide mixed solvent is 1g~10g:100mL~400mL; In S32, the ratio of carboxyl-functionalized titanium dioxide, coupling agent solution, and boron nitride grafted modified basalt fiber is 10g~20g:100mL~400mL:1g~50g.
7. The method for preparing the basalt fiber composite material as described in claim 1, characterized in that, In step three, the preparation method of the polyamino coupling agent includes: Step A: Dissolve aluminum isopropoxide in anhydrous ethanol, add citric acid and glacial acetic acid, heat to 60℃~70℃, turn on reflux, and reflux at a constant temperature for 2h~5h to obtain aluminum citrate chelate solution. Step B: Add coupling agent KH-792 dropwise to the aluminate citrate chelate solution. During the dropwise addition, maintain the system temperature at 60℃~70℃ and the stirring speed at 200rpm~300rpm. After the dropwise addition is complete, add deionized water to the system, and then raise the system temperature to 70℃~80℃. Keep the stirring speed constant and react at this temperature for 3~4 hours to obtain the polyaminoaluminate-siloxane hybrid reaction solution. Step C: Distill the polyaminoaluminate-siloxane hybrid reaction solution under reduced pressure at 60℃~90℃ and a vacuum of -0.09MPa for 10min~30min, and dry the crude product under vacuum at 60℃~80℃ for 2h~6h to obtain the polyamino coupling agent.
8. The method for preparing the basalt fiber composite material as described in claim 7, characterized in that, In step A, the ratio of aluminum isopropoxide, anhydrous ethanol, citric acid, and glacial acetic acid is 1 mol~2 mol: 3 mol~5 mol: 0.5 mol~1 mol: 10 mL~20 mL. In step B, the ratio of coupling agent KH-792 to aluminate citrate chelate solution is 1g~20g:100mL~200mL.
9. A basalt fiber composite material, characterized in that, The basalt fiber composite material is prepared by the method for preparing basalt fiber composite material according to any one of claims 1-8.
10. An application of the basalt fiber composite material as described in claim 9, characterized in that, The basalt fiber composite material is used to prepare flame-retardant fabrics.