Reinforcing fiber for a laminate flooring and a method for producing the same

Abstract

The application relates to the technical field of composite floor, and discloses a reinforcing fiber for composite floor and a preparation method thereof. The reinforcing fiber comprises the following raw materials in parts by weight: 35-45 parts of bamboo fiber, 6-10 parts of modified polyamide fiber, 5-9 parts of polyethylene fiber, 3-6 parts of glass fiber, 8-12 parts of modified silicon dioxide and 1-2 parts of lubricant; the bamboo fiber is used as the main raw material, and other auxiliary fibers are added to improve the comprehensive performance of the reinforcing fiber; the added modified polyamide fiber improves the flame-retardant performance and heat-resistant performance of the reinforcing fiber; and the added modified silicon dioxide improves the wear resistance and mechanical performance of the reinforcing fiber. Therefore, the reinforcing fiber prepared by the application can effectively improve the flame-retardant performance, heat-resistant performance, wear resistance and mechanical performance of the composite floor when the reinforcing fiber is applied to the composite floor.

Description

Technical Field

[0001] This invention relates to the field of composite flooring technology, and more specifically to a reinforcing fiber for composite flooring and its preparation method. Background Technology

[0002] Flooring is an essential decorative material in building construction, made of wood or other materials. Composite flooring is a type of flooring that has had its natural structure altered to achieve specific physical properties. Common types of flooring include: natural landscape / feng shui flooring, solid wood flooring, engineered wood flooring, solid wood composite flooring, PVC flooring, bamboo flooring, cork flooring, and wood-plastic composite flooring. Currently, wood-plastic composite flooring is the most commonly used. It is made by mixing and granulating polyolefins, wood flour, bamboo flour, and additives, then extruding the mixture. However, existing wood-plastic composite flooring typically uses only plant fibers, polyolefins, and additives as raw materials, resulting in poor wear resistance, brittleness, and flammability, thus limiting its application in some areas.

[0003] Reinforcing fibers are materials used to improve the overall performance of composite flooring. They are typically made from plant fibers, other fibers (such as polyethylene fibers, polyamide fibers, and glass fibers), fillers, and additives. To address the flammability issue of composite flooring, polyamide fibers can be modified to introduce flame-retardant structures into their molecular chains, thereby improving their flame-retardant properties. To address the issue of composite flooring's wear resistance no longer meeting market demands, wear-resistant fillers, such as silica and calcium carbonate, can be added and modified to improve their dispersion within the matrix of the synthetic reinforcing fibers, further enhancing their wear and heat resistance. Furthermore, to address the brittleness of composite flooring, core-shell structured fillers can be prepared to improve the mechanical properties of the reinforcing fibers. Therefore, by applying reinforcing fibers with flame retardancy, wear resistance, and excellent mechanical properties to composite flooring, the overall performance of composite flooring can be improved. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a reinforcing fiber for composite flooring and its preparation method.

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] A composite flooring reinforcing fiber comprises the following raw materials in parts by weight: 35-45 parts bamboo fiber, 6-10 parts modified polyamide fiber, 5-9 parts polyethylene fiber, 3-6 parts glass fiber, 8-12 parts modified silica, and 1-2 parts lubricant.

[0007] The modified polyamide fiber is prepared by the following steps:

[0008] Step A1: Add phosphorus oxychloride to a flask containing acetonitrile, heat to 60-70℃, add (4-hydroxy-phenyl)-diethyl phosphate acetonitrile solution in five portions, with an interval of 20 min between each addition. After the addition is completed, raise the system temperature to 80-90℃ and reflux for 16-22 h. After the reaction is completed, filter and dry to obtain the phosphorus-containing flame retardant precursor.

[0009] Furthermore, the ratio of phosphorus oxychloride, acetonitrile, and (4-hydroxy-phenyl)-diethyl phosphate acetonitrile solution is 10.2-30.6 g: 50 mL: 250 mL. The (4-hydroxy-phenyl)-diethyl phosphate acetonitrile solution is prepared by mixing (4-hydroxy-phenyl)-diethyl phosphate and acetonitrile in a ratio of 25.2-75.5 g: 250 mL.

[0010] Step A2: Add 1,11-diaminoundecane-6-ol to a mixture of chloroform and acetonitrile and stir until homogeneous. Then add trimethylchlorosilane and reflux for 2 hours. Cool to 0°C. Add triethylamine and triphenylmethyl chloride dissolved in chloroform to the reactor and continue stirring for 1 hour. Add methanol and mix until homogeneous. Concentrate, extract and dry to obtain intermediate product 1.

[0011] Furthermore, the ratio of 1,11-diaminoundecane-6-ol, chloroform, acetonitrile, trimethylchlorosilane, chloroform, triethylamine, triphenylmethyl chloride, and methanol is 0.01 mol: 15-20 mL: 3-4 mL: 0.01 mol: 10 mL: 0.02-0.03 mol: 0.01-0.025 mol: 2 mL.

[0012] Step A3: Add the phosphorus-containing flame retardant precursor and acetonitrile to a flask and stir until homogeneous. Slowly add the acetonitrile solution of intermediate product 1 and stir at room temperature for 15 min. Then slowly raise the system temperature to 50-60℃ and keep it at that temperature for 30 min. Then raise the temperature to 85℃ and continue the reaction for 4-6 h. After the reaction is complete, cool to room temperature, filter, add acetic acid solution and reflux for 10 min. Filter again, wash and dry to obtain the terminal amino flame retardant product.

[0013] Furthermore, the ratio of the phosphorus-containing flame retardant precursor, acetonitrile, intermediate product 1 acetonitrile solution, and acetic acid solution is 14.1-42.3 g: 100 mL: 200 mL: 100 mL. The intermediate product 1 acetonitrile solution is prepared by mixing intermediate product 1 and acetonitrile at a ratio of 24.2-72.6 g: 200 mL. The mass ratio of acetic acid to deionized water in the acetic acid solution is 1:1.

[0014] Step A4: Add sebacic acid, dodecanediamine, and terminal amino flame retardant product to a reactor containing deionized water. After stirring and mixing evenly, adjust the pH to 7.3-7.5. Then transfer the mixture to a high-temperature and high-pressure reactor, introduce nitrogen gas, turn on the reactor and heat to 210-230℃. Stir and react for 2-3 hours. After the reaction is completed, raise the temperature of the reactor to 260℃ and continue the reaction under vacuum for 0.5-1.5 hours. Then restore the pressure to normal, discharge the material and place it in cooling water. After cooling to room temperature, dry and crush to obtain modified polyamide fiber.

[0015] Furthermore, the ratio of sebacic acid, dodecanoic diamine, terminal amino flame retardant product, and deionized water is 20-40g: 22-42g: 1.26-5.74g: 40-60mL.

[0016] The modified silica is prepared by the following steps:

[0017] Step B1: Add silica to a mixture of ethanol and deionized water, stir and mix evenly, add γ-aminopropyltriethoxysilane and stir to react for 5-8 hours. After the reaction is complete, centrifuge, wash and dry to obtain aminated silica.

[0018] Furthermore, the ratio of silicon dioxide, ethanol, deionized water and γ-aminopropyltriethoxysilane is 1g:30mL:5mL:1-2mL.

[0019] Step B2: Add diethanolamine and succinic anhydride to a flask, then add aminated silica. After ultrasonic stirring for 30 min, raise the system temperature to 70-80℃ and maintain the temperature while stirring for 1-2 h. Raise the system temperature again to 110-120℃, add toluene, and react under nitrogen for 6 h. Then lower the temperature to 60-70℃, slowly add epichlorohydrin acetone solution and boron trifluoride diethyl ether, reflux for 2-3 h, distill under reduced pressure, add 25 wt% sodium hydroxide solution, and raise the temperature to 75-85℃ for 3 h. After the reaction is complete, filter, distill under reduced pressure, centrifuge, and dry to obtain modified silica.

[0020] Furthermore, the ratio of diethanolamine, succinic anhydride, aminated silica, toluene, epichlorohydrin acetone solution, boron trifluoride ether, and sodium hydroxide solution is 1.5-3 g: 1.57-3.14 g: 0.8-1.5 g: 20 mL: 20 mL: 0.8-1.2 g: 15 mL. The epichlorohydrin acetone solution is prepared by mixing epichlorohydrin and acetone in a 1:1 molar ratio.

[0021] A method for preparing reinforcing fibers for composite flooring includes the following steps:

[0022] Step S1: Weigh the raw materials according to the weight proportions, crush the bamboo fiber into powder, and mix it evenly with modified polyamide fiber, polyethylene fiber, glass fiber, modified silica and lubricant. Stir at 100-120℃ for 30-50 minutes to obtain the premix.

[0023] Step S2: Put the premixed material into an extrusion granulator, extrude and granulate at 170-210℃, and crush to obtain the reinforcing fiber for composite flooring.

[0024] The beneficial effects of this invention are:

[0025] The reinforcing fiber in this invention uses bamboo fiber as the main raw material, with the addition of other auxiliary fibers to improve its overall performance. Specifically, the added modified polyamide fiber enhances the flame retardant and heat resistance properties of the reinforcing fiber, while the added modified silica improves its abrasion resistance and mechanical properties. Therefore, applying the reinforcing fiber prepared according to this invention to composite flooring can effectively improve the flame retardant, heat resistance, abrasion resistance, and mechanical properties of the composite flooring.

[0026] In the modified polyamide fiber, firstly, the chlorine atom in phosphorus oxychloride reacts with the hydroxyl group in (4-hydroxy-phenyl)-diethyl phosphate to generate a phosphorus-containing flame retardant precursor; secondly, the amino group in 1,11-diaminoundecane-6-ol is protected by triphenylmethyl to generate intermediate product 1; thirdly, the remaining chlorine atom in the phosphorus-containing flame retardant precursor reacts with the hydroxyl group in intermediate product 1, followed by deprotection of the amino group to generate a terminal amino flame retardant product; finally, modified polyamide fiber is synthesized using sebacic acid, dodecanediamine, and the terminal amino flame retardant product as raw materials. Modified polyamide fiber uses polyamide fiber with excellent wear resistance as the base material, which improves the wear resistance of the matrix. Then, terminal amino flame retardant products are introduced into the polyamide fiber to improve the flame retardant performance of the matrix. This is because when the matrix burns, the phosphate ester groups in the polyamide fiber decompose into phosphoric acid when heated. The phosphoric acid reacts with the carbon source in the matrix to form a char layer. The char layer can block the transfer of oxygen and heat, thereby slowing down the combustion rate and the spread of flame. At the same time, the phosphate ester groups can also decompose to produce gases. These gases can react with the free radicals generated by combustion to inhibit the formation of flame, thereby improving the flame retardant performance of the matrix. In addition, the side chains of the modified polyamide fiber also contain benzene ring structures, which improves the heat resistance of the matrix.

[0027] In the modified silica, the silica is first surface-treated with a silane coupling agent to generate aminated silica; then, using diethanolamine and succinic anhydride as raw materials, hyperbranched polymers are grafted onto the surface of the aminated silica, and epichlorohydrin is used to introduce epoxy groups into the hyperbranched polymers to generate modified silica. In modified silica, silica with excellent wear resistance is used as the core layer, and its surface is aminated to improve the dispersibility of silica in the matrix, thereby increasing the wear resistance and heat resistance of the matrix. Hyperbranched polymer grafted onto the silica surface forms the shell layer, which improves the mechanical properties of the matrix. This is because the epoxy groups on the surface of the hyperbranched polymer can react with the hydroxyl groups on the surface of bamboo fiber. At the same time, the hyperbranched structure and the molecular chains in the matrix can also form physical entanglement. As the degree of dispersion increases, the physical crosslinking points formed in the matrix will gradually form a network structure. This structure can play a role in uniformly distributing the load. When the matrix is ​​subjected to external force, the stress generated inside is quickly transferred to silica, while dispersing the stress, thereby effectively improving the mechanical properties of the matrix. Detailed Implementation

[0028] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] Example 1

[0030] 1) Modified polyamide fibers are prepared by the following steps:

[0031] Step A1: Add 10.2g of phosphorus oxychloride to a flask containing 50mL of acetonitrile, heat to 60℃, and add 250mL of (4-hydroxy-phenyl)-diethyl phosphate acetonitrile solution in five portions, with an interval of 20min between each addition. After the addition is completed, raise the system temperature to 80℃ and reflux for 16h. After the reaction is completed, filter and dry to obtain the phosphorus-containing flame retardant precursor. The (4-hydroxy-phenyl)-diethyl phosphate acetonitrile solution is prepared by mixing (4-hydroxy-phenyl)-diethyl phosphate and acetonitrile in a volume ratio of 25.2g:250mL.

[0032] Step A2: Add 0.01 mol of 1,11-diaminoundecane-6-ol to a mixture of 15 mL of chloroform and 3 mL of acetonitrile and stir until homogeneous. Then add 0.01 mol of trimethylchlorosilane and reflux for 2 h. Cool to 0 °C. Add 0.02 mol of triethylamine and 0.01 mol of triphenylmethyl chloride dissolved in 10 mL of chloroform to the reactor and continue stirring for 1 h. Then add 2 mL of methanol and mix until homogeneous. Concentrate, extract and dry to obtain intermediate product 1.

[0033] Step A3: Add 14.1g of phosphorus-containing flame retardant precursor and 100mL of acetonitrile to a flask and stir until homogeneous. Slowly add 200mL of intermediate product 1 acetonitrile solution and stir at room temperature for 15min. Then slowly raise the system temperature to 50℃ and keep it at that temperature for 30min. Then raise the temperature to 85℃ and continue the reaction for 4h. After the reaction is complete, cool to room temperature, filter, and then add 100mL of acetic acid solution and reflux for 10min. Filter again, wash, and dry to obtain the terminal amino flame retardant product. The intermediate product 1 acetonitrile solution is prepared by mixing intermediate product 1 and acetonitrile in a volume ratio of 24.2g:200mL. The mass ratio of acetic acid to deionized water in the acetic acid solution is 1:1.

[0034] Step A4: Add 20g sebacic acid, 22g dodecanediamine and 1.26g terminal amino flame retardant product to a reactor containing 40mL deionized water. After stirring and mixing evenly, adjust the pH to 7.3. Then transfer the mixture to a high-temperature and high-pressure reactor, introduce nitrogen gas, turn on the reactor and heat to 210℃. Stir and react for 2 hours. After the reaction is completed, raise the temperature of the reactor to 260℃ and continue to react under vacuum for 0.5 hours. Then restore the pressure to normal, discharge the material and place it in cooling water. After cooling to room temperature, dry and crush to obtain modified polyamide fiber.

[0035] 2) Modified silica is prepared by the following steps:

[0036] Step B1: Add 1g of silicon dioxide to a mixture of 30mL of ethanol and 5mL of deionized water, stir and mix evenly, add 1mL of γ-aminopropyltriethoxysilane and stir to react for 5h. After the reaction is completed, centrifuge, wash and dry to obtain aminated silicon dioxide.

[0037] Step B2: Add 1.5g of diethanolamine and 1.57g of succinic anhydride to a flask, then add 0.8g of aminated silica. After ultrasonic stirring for 30min, raise the system temperature to 70℃ and maintain the temperature while stirring for 1h. Raise the system temperature again to 110℃, add 20mL of toluene, and react under nitrogen for 6h. Then lower the temperature to 60℃, slowly add 20mL of epichlorohydrin-acetone solution and 0.8g of boron trifluoride ether, reflux for 2h, then distill under reduced pressure. Add 15mL of 25wt% sodium hydroxide solution and raise the temperature to 75℃ for 3h. After the reaction is complete, filter, distill under reduced pressure, centrifuge, and dry to obtain modified silica. The epichlorohydrin-acetone solution is a mixture of epichlorohydrin and acetone in a 1:1 molar ratio.

[0038] Example 2

[0039] 1) Modified polyamide fibers are prepared by the following steps:

[0040] Step A1: Add 20.4g of phosphorus oxychloride to a flask containing 50mL of acetonitrile, heat to 65℃, and add 250mL of (4-hydroxy-phenyl)-diethyl phosphate acetonitrile solution in five portions, with an interval of 20min between each addition. After the addition is completed, raise the system temperature to 85℃ and reflux for 19h. After the reaction is completed, filter and dry to obtain the phosphorus-containing flame retardant precursor. The (4-hydroxy-phenyl)-diethyl phosphate acetonitrile solution is prepared by mixing (4-hydroxy-phenyl)-diethyl phosphate and acetonitrile in a volume ratio of 50.5g:250mL.

[0041] Step A2: Add 0.01 mol of 1,11-diaminoundecane-6-ol to a mixture of 17 mL of chloroform and 3.5 mL of acetonitrile and stir until homogeneous. Then add 0.01 mol of trimethylchlorosilane and reflux for 2 h. Cool to 0 °C. Add 0.025 mol of triethylamine and 0.02 mol of triphenylmethyl chloride dissolved in 10 mL of chloroform to the reactor and continue stirring for 1 h. Then add 2 mL of methanol and mix until homogeneous. Concentrate, extract, and dry to obtain intermediate product 1.

[0042] Step A3: Add 28.2g of phosphorus-containing flame retardant precursor and 100mL of acetonitrile to a flask and stir until homogeneous. Slowly add 200mL of intermediate product 1 acetonitrile solution and stir at room temperature for 15min. Then slowly raise the system temperature to 55℃ and keep it at that temperature for 30min. Then raise the temperature to 85℃ and continue the reaction for 5h. After the reaction is complete, cool to room temperature, filter, and then add 100mL of acetic acid solution and reflux for 10min. Filter again, wash, and dry to obtain the terminal amino flame retardant product. The intermediate product 1 acetonitrile solution is prepared by mixing intermediate product 1 and acetonitrile in a volume ratio of 48.4g:200mL. The mass ratio of acetic acid to deionized water in the acetic acid solution is 1:1.

[0043] Step A4: Add 30g sebacic acid, 32g dodecanediamine and 3.1g terminal amino flame retardant product to a reactor containing 50mL deionized water. After stirring and mixing evenly, adjust the pH to 7.4. Then transfer the mixture to a high-temperature and high-pressure reactor, introduce nitrogen gas, turn on the reactor and heat to 220℃. Stir and react for 2.5h. After the reaction is completed, raise the temperature of the reactor to 260℃ and continue to react under vacuum for 1h. Then restore normal pressure, discharge the material and place it in cooling water. After cooling to room temperature, dry and crush to obtain modified polyamide fiber.

[0044] 2) Modified silica is prepared by the following steps:

[0045] Step B1: Add 1g of silicon dioxide to a mixture of 30mL of ethanol and 5mL of deionized water, stir and mix evenly, add 1.5mL of γ-aminopropyltriethoxysilane and stir to react for 6.5h. After the reaction is completed, centrifuge, wash and dry to obtain aminated silicon dioxide.

[0046] Step B2: Add 2.25g of diethanolamine and 2.35g of succinic anhydride to a flask, then add 1.15g of aminated silica. After ultrasonic stirring for 30min, raise the system temperature to 75℃ and maintain the temperature while stirring for 1.5h. Raise the system temperature again to 115℃, add 20mL of toluene, and react under nitrogen for 6h. Then lower the temperature to 65℃, slowly add 20mL of epichlorohydrin-acetone solution and 1g of boron trifluoride ether, reflux for 2.5h, then distill under reduced pressure. Add 15mL of 25wt% sodium hydroxide solution and raise the temperature to 80℃ for 3h. After the reaction is complete, filter, distill under reduced pressure, centrifuge, and dry to obtain modified silica. The epichlorohydrin-acetone solution is a mixture of epichlorohydrin and acetone in a 1:1 molar ratio.

[0047] Example 3

[0048] 1) Modified polyamide fibers are prepared by the following steps:

[0049] Step A1: Add 30.6g of phosphorus oxychloride to a flask containing 50mL of acetonitrile, heat to 70℃, and add 250mL of (4-hydroxy-phenyl)-diethyl phosphate acetonitrile solution in five portions, with an interval of 20min between each addition. After the addition is completed, raise the system temperature to 90℃ and reflux for 22h. After the reaction is completed, filter and dry to obtain the phosphorus-containing flame retardant precursor. The (4-hydroxy-phenyl)-diethyl phosphate acetonitrile solution is prepared by mixing (4-hydroxy-phenyl)-diethyl phosphate and acetonitrile in a volume ratio of 75.5g:250mL.

[0050] Step A2: Add 0.01 mol of 1,11-diaminoundecane-6-ol to a mixture of 20 mL of chloroform and 4 mL of acetonitrile and stir until homogeneous. Then add 0.01 mol of trimethylchlorosilane and reflux for 2 h. Cool to 0 °C. Add 0.03 mol of triethylamine and 0.025 mol of triphenylmethyl chloride dissolved in 10 mL of chloroform to the reactor and continue stirring for 1 h. Then add 2 mL of methanol and mix until homogeneous. Concentrate, extract and dry to obtain intermediate product 1.

[0051] Step A3: Add 42.3g of phosphorus-containing flame retardant precursor and 100mL of acetonitrile to a flask and stir until homogeneous. Slowly add 200mL of intermediate product 1 acetonitrile solution and stir at room temperature for 15min. Then slowly raise the system temperature to 60℃ and keep it at that temperature for 30min. Then raise the temperature to 85℃ and continue the reaction for 6h. After the reaction is complete, cool to room temperature, filter, and then add 100mL of acetic acid solution and reflux for 10min. Filter again, wash, and dry to obtain the terminal amino flame retardant product. The intermediate product 1 acetonitrile solution is prepared by mixing intermediate product 1 and acetonitrile in a volume ratio of 72.6g:200mL. The mass ratio of acetic acid to deionized water in the acetic acid solution is 1:1.

[0052] Step A4: Add 40g sebacic acid, 42g dodecanediamine and 5.74g terminal amino flame retardant product to a reactor containing 60mL of deionized water. After stirring and mixing evenly, adjust the pH to 7.5. Then transfer the mixture to a high-temperature and high-pressure reactor, introduce nitrogen gas, turn on the reactor and heat to 230℃. Stir and react for 3 hours. After the reaction is completed, raise the temperature of the reactor to 260℃ and continue to react under vacuum for 1.5 hours. Then restore the pressure to normal, discharge the material and place it in cooling water. After cooling to room temperature, dry and crush to obtain modified polyamide fiber.

[0053] 2) Modified silica is prepared by the following steps:

[0054] Step B1: Add 1g of silicon dioxide to a mixture of 30mL ethanol and 5mL deionized water, stir and mix evenly, add 2mL of γ-aminopropyltriethoxysilane and stir to react for 8h. After the reaction is completed, centrifuge, wash and dry to obtain aminated silicon dioxide.

[0055] Step B2: Add 3g of diethanolamine and 3.14g of succinic anhydride to a flask, then add 1.5g of aminated silica. After ultrasonic stirring for 30min, raise the system temperature to 80℃ and maintain the temperature while stirring for 1-2h. Raise the system temperature again to 120℃, add 20mL of toluene, and react under nitrogen for 6h. Then lower the temperature to 70℃, slowly add 20mL of epichlorohydrin-acetone solution and 1.2g of boron trifluoride ether, reflux for 3h, then distill under reduced pressure. Add 15mL of 25wt% sodium hydroxide solution and raise the temperature to 85℃ for 3h. After the reaction is complete, filter, distill under reduced pressure, centrifuge, and dry to obtain modified silica. The epichlorohydrin-acetone solution is a mixture of epichlorohydrin and acetone in a 1:1 molar ratio.

[0056] Example 4

[0057] A method for preparing reinforcing fibers for composite flooring includes the following steps:

[0058] 35 parts bamboo fiber, 6 parts modified polyamide fiber prepared in Example 1, 5 parts polyethylene fiber, 3 parts glass fiber, 8 parts modified silica prepared in Example 1, and 1 part stearic acid.

[0059] Step S1: Weigh the raw materials according to the weight proportions, crush the bamboo fiber into powder, and mix it evenly with the modified polyamide fiber, polyethylene fiber, glass fiber, modified silica and stearic acid prepared in Example 1. Stir at 100°C for 30 minutes to obtain the premix.

[0060] Step S2: The premixed material is fed into an extrusion granulator, extruded and granulated at 170°C, and then crushed to obtain the reinforcing fiber for composite flooring.

[0061] Example 5

[0062] A method for preparing reinforcing fibers for composite flooring includes the following steps:

[0063] 40 parts bamboo fiber, 8 parts modified polyamide fiber prepared in Example 2, 7 parts polyethylene fiber, 4.5 parts glass fiber, 10 parts modified silica prepared in Example 2, and 1.5 parts stearic acid;

[0064] Step S1: Weigh the raw materials according to the weight proportions, crush the bamboo fiber into powder, and mix it evenly with the modified polyamide fiber, polyethylene fiber, glass fiber, modified silica and stearic acid prepared in Example 2. Stir at 110°C for 40 minutes to obtain a premix.

[0065] Step S2: The premixed material is fed into an extrusion granulator, extruded and granulated at 190°C, and then crushed to obtain the reinforcing fiber for composite flooring.

[0066] Example 6

[0067] A method for preparing reinforcing fibers for composite flooring includes the following steps:

[0068] 45 parts bamboo fiber, 10 parts modified polyamide fiber prepared in Example 3, 9 parts polyethylene fiber, 6 parts glass fiber, 12 parts modified silica prepared in Example 3, and 2 parts stearic acid.

[0069] Step S1: Weigh the raw materials according to the weight proportions, crush the bamboo fiber into powder, and mix it evenly with the modified polyamide fiber, polyethylene fiber, glass fiber, modified silica and stearic acid prepared in Example 3. Stir at 120°C for 50 minutes to obtain the premix.

[0070] Step S2: The premixed material is fed into an extrusion granulator, extruded and granulated at 210°C, and then crushed to obtain the reinforcing fiber for composite flooring.

[0071] Comparative Example 1

[0072] This comparative example is a reinforced fiber, which differs from Example 6 in that an equal amount of polyamide fiber is used instead of the modified polyamide fiber prepared in Example 3, while all other aspects are the same.

[0073] Comparative Example 2

[0074] This comparative example is a reinforced fiber, which differs from Example 6 in that an equal amount of silica is used instead of the modified silica prepared in Example 3, while all other aspects are the same.

[0075] Performance testing: 9 kg of polypropylene resin was weighed and added to the reinforcing fibers prepared in Examples 4-6 and Comparative Examples 1-2. After being mixed evenly at 90°C, the mixture was fed into a screw extruder for melting, shearing, and extrusion. The mixture was then conveyed to a die-forming machine for cooling to obtain samples, which were subsequently designated as Samples 1-5. The obtained samples were subjected to performance testing according to the following methods:

[0076] Flame retardancy testing: Flame retardancy testing and classification are conducted according to EN 13501;

[0077] Mechanical property testing: Its mechanical properties were tested in accordance with GB / T1040-2006;

[0078] Heat resistance test: Heat distortion temperature shall be tested in accordance with GB1634-79;

[0079] Abrasion resistance test: Wear rate was tested according to GB3960-88. The test results are shown in the table below:

[0080]

[0081] As can be seen from the table above, the composite flooring prepared using the reinforcing fibers of this invention has excellent flame retardant properties, mechanical properties, heat resistance, and wear resistance. Therefore, applying the reinforcing fibers of this invention to composite flooring can improve the overall performance of the flooring.

[0082] The above content is merely an example and illustration of the concept of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described or use similar methods to replace them, as long as they do not deviate from the scope defined by the inventive concept, they should all fall within the protection scope of the present invention.

Claims

1. A reinforcing fiber for composite flooring, characterized in that, The raw materials include the following parts by weight: 35-45 parts bamboo fiber, 6-10 parts modified polyamide fiber, 5-9 parts polyethylene fiber, 3-6 parts glass fiber, 8-12 parts modified silica, and 1-2 parts lubricant. The modified polyamide fiber is prepared by the following steps: Step A1: Add phosphorus oxychloride to a flask containing acetonitrile, heat to 60-70℃, add (4-hydroxy-phenyl)-diethyl phosphate acetonitrile solution in five portions, with an interval of 20 min between each addition. After the addition is completed, raise the system temperature to 80-90℃ and reflux for 16-22 h. After the reaction is completed, filter and dry to obtain the phosphorus-containing flame retardant precursor. Step A2: Add 1,11-diaminoundecane-6-ol to a mixture of chloroform and acetonitrile and stir until homogeneous. Then add trimethylchlorosilane and reflux for 2 hours. Cool to 0°C. Add triethylamine and triphenylmethyl chloride dissolved in chloroform to the reactor and continue stirring for 1 hour. Add methanol and mix until homogeneous. Concentrate, extract and dry to obtain intermediate product 1. Step A3: Add the phosphorus-containing flame retardant precursor and acetonitrile to a flask and stir until homogeneous. Slowly add the acetonitrile solution of intermediate product 1 and stir at room temperature for 15 min. Then slowly raise the system temperature to 50-60℃ and keep it at that temperature for 30 min. Then raise the temperature to 85℃ and continue the reaction for 4-6 h. After the reaction is complete, cool to room temperature, filter, add acetic acid solution and reflux for 10 min. Filter again, wash and dry to obtain the terminal amino flame retardant product. Step A4: Add sebacic acid, dodecanediamine, and terminal amino flame retardant product to a reactor containing deionized water. After stirring and mixing evenly, adjust the pH to 7.3-7.

5. Then transfer the mixture to a high-temperature and high-pressure reactor, introduce nitrogen gas, turn on the reactor and heat to 210-230℃. Stir and react for 2-3 hours. After the reaction is completed, raise the temperature of the reactor to 260℃ and continue the reaction under vacuum for 0.5-1.5 hours. Then restore the pressure to normal, discharge the material and place it in cooling water. After cooling to room temperature, dry and crush to obtain modified polyamide fiber. The modified silica is prepared by the following steps: Step B1: Add silica to a mixture of ethanol and deionized water, stir and mix evenly, add γ-aminopropyltriethoxysilane and stir to react for 5-8 hours. After the reaction is complete, centrifuge, wash and dry to obtain aminated silica. Step B2: Add diethanolamine and succinic anhydride to a flask, then add aminated silica. After ultrasonic stirring for 30 min, raise the system temperature to 70-80℃ and maintain the temperature while stirring for 1-2 h. Raise the system temperature again to 110-120℃, add toluene, and react under nitrogen for 6 h. Then lower the temperature to 60-70℃ and slowly add epichlorohydrin acetone solution and boron trifluoride diethyl ether. Reflux for 2-3 h, then distill under reduced pressure. Add 25 wt% sodium hydroxide solution and raise the temperature to 75-85℃ for 3 h. After the reaction is complete, filter, distill under reduced pressure, centrifuge, and dry to obtain modified silica.

2. The reinforcing fiber for composite flooring according to claim 1, characterized in that, In step A1, the ratio of phosphorus oxychloride, acetonitrile, and (4-hydroxy-phenyl)-diethyl phosphate acetonitrile solution is 10.2-30.6 g: 50 mL: 250 mL. The (4-hydroxy-phenyl)-diethyl phosphate acetonitrile solution is prepared by mixing (4-hydroxy-phenyl)-diethyl phosphate and acetonitrile in a ratio of 25.2-75.5 g: 250 mL.

3. The reinforcing fiber for composite flooring according to claim 1, characterized in that, In step A2, the ratio of 1,11-diaminoundecane-6-ol, chloroform, acetonitrile, trimethylchlorosilane, chloroform, triethylamine, triphenylmethyl chloride, and methanol is 0.01 mol: 15-20 mL: 3-4 mL: 0.01 mol: 10 mL: 0.02-0.03 mol: 0.01-0.025 mol: 2 mL.

4. The reinforcing fiber for composite flooring according to claim 1, characterized in that, In step A3, the ratio of the phosphorus-containing flame retardant precursor, acetonitrile, intermediate product 1 acetonitrile solution, and acetic acid solution is 14.1-42.3 g: 100 mL: 200 mL: 100 mL. The intermediate product 1 acetonitrile solution is prepared by mixing intermediate product 1 and acetonitrile at a ratio of 24.2-72.6 g: 200 mL. The mass ratio of acetic acid to deionized water in the acetic acid solution is 1:

1.

5. The reinforcing fiber for composite flooring according to claim 1, characterized in that, In step A4, the ratio of sebacic acid, dodecanediamine, terminal amino flame retardant product, and deionized water is 20-40g: 22-42g: 1.26-5.74g: 40-60mL.

6. The reinforcing fiber for composite flooring according to claim 1, characterized in that, In step B1, the ratio of silica, ethanol, deionized water and γ-aminopropyltriethoxysilane is 1g:30mL:5mL:1-2mL.

7. The reinforcing fiber for composite flooring according to claim 1, characterized in that, In step B2, the ratio of diethanolamine, succinic anhydride, aminated silica, toluene, epichlorohydrin acetone solution, boron trifluoride ether, and sodium hydroxide solution is 1.5-3 g: 1.57-3.14 g: 0.8-1.5 g: 20 mL: 20 mL: 0.8-1.2 g: 15 mL. The epichlorohydrin acetone solution is prepared by mixing epichlorohydrin and acetone in a 1:1 molar ratio.

8. The method for preparing reinforcing fibers for composite flooring according to claim 1, characterized in that, Includes the following steps: Step S1: Weigh the raw materials according to the weight proportions, crush the bamboo fiber into powder, and mix it evenly with modified polyamide fiber, polyethylene fiber, glass fiber, modified silica and lubricant. Stir at 100-120℃ for 30-50 minutes to obtain the premix. Step S2: Put the premixed material into an extrusion granulator, extrude and granulate at 170-210℃, and crush to obtain the reinforcing fiber for composite flooring.

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