High flame-retardant rag felt and its production process

Abstract

The application discloses a kind of high flame-retardant waste spinning blanket and production process, belong to waste spinning blanket material technical field, including the following steps: S1, after being recycled, sorting, disinfecting, the nylon waste spinning is again opened and carded, and pretreated fiber is obtained;S2, pretreated fiber is immersed in isopropyl alcohol solution, then 10wt% concentration chloroacetic acid solution is added, and is stirred and reacted at 50-60 DEG C for 1-1.5h, then after deionized water washing, drying, modified fiber is obtained;S3, modified fiber, modified chain extender, amino nano silicon dioxide, diethyl hypophosphite aluminum are mixed uniformly, and are added to melt spinning machine to spin, after combing, paving into net, again after needle punching processing, hot-pressing treatment, high flame-retardant waste spinning blanket is obtained.The application uses nylon waste spinning as base material, and under the synergistic effect of modified chain extender, amino nano silicon dioxide and flame retardant, the tear resistance and flame retardant performance of waste spinning blanket are improved.

Description

Technical Field

[0001] This invention belongs to the field of waste textile felt material preparation technology, specifically relating to a high flame-retardant waste textile felt and its production process. Background Technology

[0002] With increasing environmental awareness and the popularization of the concept of resource recycling, the recycling and reuse of waste textiles has become a global concern. Nylon fiber, as a wear-resistant and non-toxic synthetic fiber, is widely used in the textile industry. While meeting market demand, it also generates a large amount of waste textiles. Therefore, waste nylon can be recycled and processed into felt to improve resource utilization. However, waste nylon is a flammable material, which produces molten droplets and toxic gases during combustion, posing a significant threat to people's lives and property.

[0003] In existing technologies, aluminum diethylphosphite is typically added during the preparation of nylon textiles to improve their flame retardant properties. Aluminum diethylphosphite, as a hypophosphite flame retardant, is widely used in both gas-phase and condensed-phase flame retardancy and exhibits excellent flame retardant performance. However, during the melt spinning and recycling of nylon waste textiles modified with aluminum diethylphosphite, repeated recycling and processing of the nylon waste textiles leads to the breakage of the nylon molecular chains, resulting in reduced flame retardant and mechanical properties. Furthermore, the thermal oxidation of aluminum diethylphosphite forms aluminum phosphate derivatives, which react with the terminal carboxyl groups of the nylon waste textile molecular chains, further promoting the degradation of the nylon waste textiles and generating more combustible gases, making the nylon waste textile felt more easily ignited. Therefore, improving the flame retardant and mechanical properties of waste textile felt is a technical problem that needs to be solved. Summary of the Invention

[0004] The purpose of this invention is to provide a high flame-retardant waste textile felt and its production process to solve the problems in the background art.

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

[0006] A production process for high flame-retardant waste textile felt includes the following steps:

[0007] S1. After recycling, sorting, and disinfecting, waste nylon fibers are opened and combed to obtain pretreated fibers.

[0008] S2. The pretreated fiber is impregnated in a 90wt% isopropanol solution, and then a 10wt% chloroacetic acid solution is added. The mixture is stirred and reacted at 50-60℃ for 1-1.5 hours. After washing with deionized water and drying, the modified fiber is obtained. The pretreated fiber is impregnated with chloroacetic acid to obtain a modified fiber with carboxyl groups grafted on its surface, which increases the number of active sites on the surface of the modified fiber, which already contains terminal amino and terminal carboxyl groups.

[0009] S3. Mix the modified fiber, modified chain extender, amino nano silica, and diethyl aluminum hypophosphite evenly, add it to a melt spinning machine for spinning, comb it, lay it into a web, and then perform needle punching and hot pressing to obtain a high flame retardant waste felt.

[0010] Furthermore, the weight ratio of the pretreated fiber, isopropanol solution, and chloroacetic acid solution is 100-120:500-600:30-60.

[0011] Furthermore, the weight ratio of the modified fiber, modified chain extender, amino nano silica, and diethyl aluminum hypophosphite is 90-110:8-11:0.5-3:6-8.

[0012] Furthermore, the modified chain extender is prepared through the following steps:

[0013] A1. Add 3,4-dihydroxybenzaldehyde to anhydrous methanol, stir and mix, then add 1,3-bis(3-aminopropyl)tetramethyldisiloxanol solution dropwise, controlling the dropwise addition time to 20-30 min. Then add glacial acetic acid and anhydrous magnesium sulfate, and stir and react for 9-10 h under a nitrogen atmosphere and at 60-70 °C. After cooling, precipitate in ice-cold deionized water, and then obtain a silicon-containing Schiff base after filtration, washing, and drying. Alternatively, using anhydrous formaldehyde as solvent, glacial acetic acid as catalyst, and anhydrous magnesium sulfate as dehydrating agent, a silicon-containing Schiff base can be obtained by reacting the aldehyde group of 3,4-dihydroxybenzaldehyde with the amino group in 1,3-bis(3-aminopropyl)tetramethyldisiloxanol.

[0014] A2. Add a silicon-containing Schiff base and potassium hydroxide to anhydrous ethanol, stir and mix, add epichlorohydrin, and stir the reaction at 60-70℃ under a nitrogen atmosphere for 3-4 hours. After cooling to room temperature, add a 40wt% potassium hydroxide aqueous solution dropwise, controlling the dropwise addition time to 0.5-1 hour. After the dropwise addition is complete, stir the reaction at 50-60℃ for 5-6 hours. After post-treatment, a modified chain extender is obtained. Using potassium hydroxide as a catalyst, a modified chain extender containing epoxy groups and organosilicon segments is obtained through the substitution reaction between the phenolic hydroxyl groups on the silicon-containing Schiff base and the chlorine on epichlorohydrin. At the same time, the added potassium hydroxide aqueous solution is used to neutralize the hydrogen chloride generated during the reaction.

[0015] Further, the ratio of anhydrous methanol, 3,4-dihydroxybenzaldehyde, 1,3-bis(3-aminopropyl)tetramethyldisiloxanol solution, glacial acetic acid, and anhydrous magnesium sulfate is 90 mL: 4-6 g: 18-20 mL: 0.5-1 mL: 0.6 g; the 1,3-bis(3-aminopropyl)tetramethyldisiloxanol solution is prepared by dissolving 1-3 mL of 1,3-bis(3-aminopropyl)tetramethyldisiloxanol in 20 mL of anhydrous methanol.

[0016] Furthermore, the ratio of the amount of anhydrous ethanol, silicon-containing Schiff base, potassium hydroxide, epichlorohydrin and potassium hydroxide aqueous solution is 60mL:3-6g:0.6g:4-8mL:4mL.

[0017] Furthermore, the post-treatment involves cooling to room temperature, filtering using a Buchner funnel, followed by rotary evaporation, dissolving in dichloromethane, washing successively with saturated sodium carbonate aqueous solution and deionized water, and then undergoing rotary evaporation again.

[0018] Furthermore, the amino-based nano-silica is prepared through the following steps:

[0019] Nano-silica was added to deionized water and ultrasonically dispersed for 30 min. 3-aminopropyltriethoxysilane was added and stirred to mix. PBS buffer was added to adjust the pH to 7-8, and the mixture was stirred and reacted at 60-70℃ for 10-12 h. After centrifugation, washing, and drying, amino-modified nano-silica was obtained. The hydroxyl groups generated by the hydrolysis of the 3-aminopropyltriethoxysilane molecular chain dehydrated and condensed with the hydroxyl groups on the surface of the nano-silica to obtain amino-modified nano-silica.

[0020] Furthermore, the ratio of deionized water, nano-silica, and 3-aminopropyltriethoxysilane is 40 mL: 1-4 g: 1-3 mL.

[0021] A highly flame-retardant waste textile felt is produced by the above production process.

[0022] The beneficial effects of this invention are:

[0023] The amino-based nano-silica of this invention, as a synergistic flame retardant, can combine with the carboxyl groups in the molecular chain of modified fibers through amino groups to form amide bonds when blended with modified fibers. This improves the compatibility between amino-based nano-silica and modified fibers. When waste textile felt is exposed to a heat source and burns, the modified nano-silica on the molecular chain of the waste textile felt can not only form a Si-OSi network structure, effectively inhibiting the formation of molten droplets, but also promote complete combustion, reduce the release of carbon monoxide and black smoke, increase the release of carbon dioxide, and improve the flame retardant effect. At the same time, aluminum diethylphosphonate can form a char layer on the surface of the waste textile felt, which works synergistically with amino-based nano-silica to promote cross-linking into char, forming a dense heat insulation layer, effectively reducing the volatilization of combustible gases. Furthermore, the decomposition of aluminum diethylphosphonate produces phosphorus-containing free radicals such as PO2· and PO·, which can effectively capture active free radicals in the gas phase during the combustion of waste textile felt, thereby terminating the chain reaction in the combustion process. With the synergy of the two, the flame retardant performance of waste textile felt is further enhanced.

[0024] This invention uses nylon waste textiles as a base material and introduces a modified chain extender containing epoxy groups and Schiff bases. When blended with modified fibers, on the one hand, the epoxy groups can couple with the terminal amino and carboxyl groups on the modified fiber molecular chains, promoting chain growth and reconnecting the modified fiber molecular chains that broke during processing. This improves the strength and tensile properties of the respun fibers and enhances the tear resistance of the waste textile felt. On the other hand, the nitrogen atom on the imine in the Schiff base can coordinate with the metal center in the aluminum phosphate salt derivative generated when aluminum diethylphosphinate is heated, forming a complex. This effectively inhibits the degradation behavior of the aluminum phosphate salt derivative on the modified fibers, avoids the generation of flammable gases, and reduces the flammability of the waste textile felt. At the same time, the modified chain extender contains organosilicon segments, which are not only flexible but also flame-retardant, further improving the flame-retardant properties of the waste textile felt. Detailed Implementation

[0025] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. 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 of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0026] Example 1

[0027] This embodiment provides a modified chain extender, which is prepared through the following steps:

[0028] A1. Add 1 mL of 1,3-bis(3-aminopropyl)tetramethyldisiloxane to 20 mL of anhydrous methanol to obtain a 1,3-bis(3-aminopropyl)tetramethyldisiloxane alcohol solution.

[0029] A2. Add 4g of 3,4-dihydroxybenzaldehyde to 90mL of anhydrous methanol, stir and mix, add 18mL of 1,3-bis(3-aminopropyl)tetramethyldisiloxanol solution dropwise, controlling the dropwise addition time to 20min, then add 0.5mL of glacial acetic acid and 0.6g of anhydrous magnesium sulfate, stir and react for 9h under a nitrogen atmosphere and at 60℃, cool and place in ice-cold deionized water to precipitate, then filter, wash and dry to obtain a silicon-containing Schiff base;

[0030] A3. Add 3g of a silicon-containing Schiff base and 0.6g of potassium hydroxide to 60mL of anhydrous ethanol, stir and mix, then add 4mL of epichlorohydrin. Under a nitrogen atmosphere and at 60℃, stir and react for 3h. After cooling to room temperature, add 4mL of 40wt% potassium hydroxide aqueous solution dropwise, controlling the dropwise addition time to 0.5h. After the dropwise addition is complete, stir and react at 50℃ for 5h. After cooling to room temperature, filter using a Buchner funnel, then dissolve in 60mL of dichloromethane after rotary evaporation, and wash successively with saturated sodium carbonate aqueous solution and deionized water, then perform rotary evaporation again to obtain the modified chain extender.

[0031] Example 2

[0032] This embodiment provides a modified chain extender, which is prepared through the following steps:

[0033] A1. Add 2 mL of 1,3-bis(3-aminopropyl)tetramethyldisiloxane to 20 mL of anhydrous methanol to obtain a 1,3-bis(3-aminopropyl)tetramethyldisiloxane alcohol solution.

[0034] A2. Add 5g of 3,4-dihydroxybenzaldehyde to 90mL of anhydrous methanol, stir and mix, add 19mL of 1,3-bis(3-aminopropyl)tetramethyldisiloxanol solution dropwise, controlling the dropwise addition time to 25min, then add 0.8mL of glacial acetic acid and 0.6g of anhydrous magnesium sulfate, stir and react for 9.5h under a nitrogen atmosphere and at 65℃, cool and place in ice-cold deionized water to precipitate, then filter, wash and dry to obtain a silicon-containing Schiff base;

[0035] A3. Add 4g of a silicon-containing Schiff base and 0.6g of potassium hydroxide to 60mL of anhydrous ethanol, stir and mix, then add 6mL of epichlorohydrin. Under a nitrogen atmosphere and at 65℃, stir and react for 3.5h. After cooling to room temperature, add 4mL of 40wt% potassium hydroxide aqueous solution dropwise, controlling the dropwise addition time to 0.8h. After the dropwise addition is complete, stir and react at 55℃ for 5.5h. After cooling to room temperature, filter using a Buchner funnel, then dissolve in 60mL of dichloromethane after rotary evaporation, and wash successively with saturated sodium carbonate aqueous solution and deionized water, then perform rotary evaporation again to obtain the modified chain extender.

[0036] Example 3

[0037] This embodiment provides a modified chain extender, which is prepared through the following steps:

[0038] A1. Add 3 mL of 1,3-bis(3-aminopropyl)tetramethyldisiloxane to 20 mL of anhydrous methanol to obtain a 1,3-bis(3-aminopropyl)tetramethyldisiloxane alcohol solution.

[0039] A2. Add 6g of 3,4-dihydroxybenzaldehyde to 90mL of anhydrous methanol, stir and mix, add 20mL of 1,3-bis(3-aminopropyl)tetramethyldisiloxanol solution dropwise, controlling the dropwise addition time to 30min, then add 1mL of glacial acetic acid and 0.6g of anhydrous magnesium sulfate, stir and react for 10h under a nitrogen atmosphere and at 70℃, cool and place in ice-cold deionized water to precipitate, then filter, wash and dry to obtain a silicon-containing Schiff base;

[0040] A3. Add 6g of a silicon-containing Schiff base and 0.6g of potassium hydroxide to 60mL of anhydrous ethanol, stir and mix, then add 8mL of epichlorohydrin. Under a nitrogen atmosphere and at 70℃, stir and react for 4h. After cooling to room temperature, add 4mL of 40wt% potassium hydroxide aqueous solution dropwise, controlling the dropwise addition time to 1h. After the dropwise addition is complete, stir and react at 60℃ for 6h. After cooling to room temperature, filter using a Buchner funnel, then dissolve in 60mL of dichloromethane by rotary evaporation, and wash successively with saturated sodium carbonate aqueous solution and deionized water, then perform rotary evaporation again to obtain the modified chain extender.

[0041] Example 4

[0042] This embodiment provides an amino-based nano-silica, which is prepared through the following steps:

[0043] Add 1g of nano-silica to 40mL of deionized water, sonicate for 30min, add 1mL of 3-aminopropyltriethoxysilane, stir and mix, add PBS buffer to adjust the pH to 7, stir and react at 60℃ for 10h, and then centrifuge, wash and dry to obtain amino nano-silica.

[0044] Example 5

[0045] Add 2g of nano-silica to 40mL of deionized water, sonicate for 30min, add 1.5mL of 3-aminopropyltriethoxysilane, stir and mix, add PBS buffer to adjust the pH to 7.5, stir and react at 65℃ for 11h, and then centrifuge, wash and dry to obtain amino nano-silica.

[0046] Example 6

[0047] Add 4g of nano-silica to 40mL of deionized water, sonicate for 30min, add 3mL of 3-aminopropyltriethoxysilane, stir and mix, add PBS buffer to adjust the pH to 8, stir and react at 70℃ for 12h, and then centrifuge, wash and dry to obtain amino nano-silica.

[0048] Example 7

[0049] This embodiment provides a production process for high flame-retardant waste textile felt, including the following steps:

[0050] S1. After recycling, sorting, and disinfecting, waste nylon fibers are opened and combed to obtain pretreated fibers.

[0051] S2. 100 parts by weight of pretreated fiber were impregnated in 500 parts by weight of 90 wt% isopropanol solution, and then 30 parts by weight of 10 wt% chloroacetic acid solution were added. The mixture was stirred and reacted at 50°C for 1 hour. After washing with deionized water and drying, modified fiber was obtained.

[0052] S3. Mix 90 parts by weight of modified fiber, 8 parts by weight of modified chain extender, 0.5 parts by weight of amino nano silica and 6 parts by weight of diethyl aluminum hypophosphite evenly, add to a melt spinning machine for spinning, combing, laying into a web, and then needle punching and hot pressing to obtain high flame retardant waste felt.

[0053] Example 8

[0054] This embodiment provides a production process for high flame-retardant waste textile felt, including the following steps:

[0055] S1. After recycling, sorting, and disinfecting, waste nylon fibers are opened and combed to obtain pretreated fibers.

[0056] S2. 110 parts by weight of pretreated fiber were impregnated in 550 parts by weight of 90 wt% isopropanol solution, and then 40 parts by weight of 10 wt% chloroacetic acid solution were added. The mixture was stirred and reacted at 55°C for 1 hour. After washing with deionized water and drying, modified fiber was obtained.

[0057] S3. Mix 100 parts by weight of modified fiber, 10 parts by weight of modified chain extender, 1.5 parts by weight of amino nano silica and 7 parts by weight of diethyl aluminum hypophosphite evenly, add to a melt spinning machine for spinning, combing, laying into a web, and then needle punching and hot pressing to obtain high flame retardant waste felt.

[0058] Example 9

[0059] This embodiment provides a production process for high flame-retardant waste textile felt, including the following steps:

[0060] S1. After recycling, sorting, and disinfecting, waste nylon fibers are opened and combed to obtain pretreated fibers.

[0061] S2. 120 parts by weight of pretreated fiber were impregnated in 600 parts by weight of 90 wt% isopropanol solution, and then 60 parts by weight of 10 wt% chloroacetic acid solution were added. The mixture was stirred and reacted at 60°C for 1.5 h. After washing with deionized water and drying, modified fiber was obtained.

[0062] S3. Mix 110 parts by weight of modified fiber, 11 parts by weight of modified chain extender, 3 parts by weight of amino nano silica and 8 parts by weight of diethyl aluminum hypophosphite evenly, add to a melt spinning machine for spinning, combing, laying into a web, and then needle punching and hot pressing to obtain high flame retardant waste felt.

[0063] Comparative Example 1: Compared with Example 7, no modified chain extender was added, and all other aspects were the same.

[0064] Comparative Example 2: Compared with Example 7, the modified chain extender was replaced with a commercially available chain extender in equal amounts, and the rest were the same.

[0065] Comparative Example 3: Compared with Example 7, amino nano-silica was replaced with an equal amount of nano-silica, and the rest were the same.

[0066] Performance tests were conducted on Examples 7-9 and Comparative Examples 1-3. Waste felt was prepared into samples of 50mm × 300mm. Tensile strength and elongation at break were tested according to GB / T 3923.1-2013; flame retardancy was tested according to GB / T 5454-2008, with the limiting oxygen index (LOI) value being the highest. A higher LIO index indicates better flame retardancy. The results are shown in Table 1.

[0067] Table 1

[0068]

[0069]

[0070] As shown in Table 1, the limiting oxygen index of the waste textile felt prepared by the modified chain extender and amino nano silica in Examples 7-9 is significantly higher than that in Comparative Examples 1-3, indicating good flame retardant properties. At the same time, the elongation at break and the tensile strength are both greater than those in Comparative Examples 1-3, indicating good strength and toughness. In addition, compared with Comparative Examples 1 and 3, Example 7 has a higher limiting oxygen index, indicating that the waste textile felt has higher flame retardant properties under the synergistic effect of the modified chain extender and amino nano silica.

[0071] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0072] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A production process for high flame-retardant waste textile felt, characterized in that, Includes the following steps: S1. After recycling, sorting, and disinfecting, waste nylon fibers are opened and combed to obtain pretreated fibers. S2. The pretreated fiber is impregnated in a 90wt% isopropanol solution, and then a 10wt% chloroacetic acid solution is added. The mixture is stirred and reacted at 50-60℃ for 1-1.5 hours. After washing with deionized water and drying, the modified fiber is obtained. S3. Mix the modified fiber, modified chain extender, amino nano silica and diethyl aluminum hypophosphite evenly, add it to the melt spinning machine for spinning, comb it, lay it into a web, and then perform needle punching and hot pressing to obtain high flame retardant waste felt. The modified chain extender is prepared by the following steps: A1. Add 3,4-dihydroxybenzaldehyde to anhydrous methanol, stir and mix, then add 1,3-bis(3-aminopropyl)tetramethyldisiloxanol solution dropwise, controlling the dropwise addition time at 20-30 min. Then add glacial acetic acid and anhydrous magnesium sulfate, and stir and react for 9-10 h under a nitrogen atmosphere and at 60-70 °C. After cooling, precipitate in ice-cold deionized water, then filter, wash, and dry to obtain a silicon-containing Schiff base. The ratio of anhydrous methanol, 3,4-dihydroxybenzaldehyde, 1,3-bis(3-aminopropyl)tetramethyldisiloxanol solution, glacial acetic acid, and anhydrous magnesium sulfate is 90 mL: 4-6 g: 18-20 mL: 0.5-1 mL: 0.6 g. The 1,3-bis(3-aminopropyl)tetramethyldisiloxanol solution is prepared by dissolving 1-3 mL of 1,3-bis(3-aminopropyl)tetramethyldisiloxane in 20 mL of anhydrous methanol. A2. Add a silicon-containing Schiff base and potassium hydroxide to anhydrous ethanol, stir and mix, add epichlorohydrin, and stir and react for 3-4 hours under a nitrogen atmosphere and at 60-70℃. After cooling to room temperature, add a 40wt% potassium hydroxide aqueous solution dropwise, controlling the dropwise addition time to 0.5-1 hour. After the dropwise addition is complete, stir and react for 5-6 hours at 50-60℃. After post-treatment, the modified chain extender is obtained. The ratio of anhydrous ethanol, silicon-containing Schiff base, potassium hydroxide, epichlorohydrin and potassium hydroxide aqueous solution is 60mL:3-6g:0.6g:4-8mL:4mL.

2. The production process of high flame-retardant waste textile felt according to claim 1, characterized in that, The weight ratio of the pretreated fiber, isopropanol solution, and chloroacetic acid solution is 100-120:500-600:30-60.

3. The production process of high flame-retardant waste felt according to claim 1, characterized in that, The weight ratio of the modified fiber, modified chain extender, amino nano silica, and diethyl aluminum hypophosphite is 90-110:8-11:0.5-3:6-8.

4. The production process of high flame-retardant waste felt according to claim 1, characterized in that, The post-treatment involves cooling to room temperature, filtering using a Buchner funnel, followed by rotary evaporation, dissolving in dichloromethane, washing successively with saturated sodium carbonate aqueous solution and deionized water, and then undergoing rotary evaporation again.

5. The production process of high flame-retardant waste felt according to claim 1, characterized in that, The amino-based nano-silica is prepared by the following steps: Nano-silica was added to deionized water and ultrasonically dispersed for 30 min. Then, 3-aminopropyltriethoxysilane was added and stirred to mix. PBS buffer was added to adjust the pH to 7-8, and the mixture was stirred and reacted at 60-70℃ for 10-12 h. After centrifugation, washing, and drying, amino-nano-silica was obtained.

6. The production process of high flame-retardant waste felt according to claim 5, characterized in that, The ratio of deionized water, nano-silica, and 3-aminopropyltriethoxysilane is 40 mL: 1-4 g: 1-3 mL.

7. A highly flame-retardant waste textile felt, characterized in that, It is produced by the production process according to any one of claims 1-6.

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