Flame-retardant antibacterial nonwoven fabric and method for manufacturing the same

Abstract

The application discloses a kind of flame-retardant antibacterial non-woven fabrics and preparation method thereof, by weight parts, including the following raw materials: homopolymer polypropylene 80-100 parts, ethylene propylene copolymer 10-20 parts, antioxidant 0.5-1.5 parts, modified antibacterial agent 2-4 parts, high-density polyethylene 10-20 parts, composite flame retardant 7-12 parts, compatible agent 5-10 parts, magnesium stearate 0.5-1 part.The non-woven fabric has excellent antibacterial property, flame retardancy, and the addition of high-density polyethylene can effectively improve the toughness of non-woven fabric, and the addition of ethylene propylene copolymer and compatibility can improve the compatibility of polypropylene and high-density polyethylene, so that the prepared non-woven fabric has better mechanical properties and good application prospect.

Description

Technical Field

[0001] This invention belongs to the field of polymer materials technology, specifically relating to a flame-retardant and antibacterial nonwoven fabric and its preparation method. Background Technology

[0002] Antibacterial nonwoven fabrics are widely used in daily life and are closely related to people's lives, especially in the medical and health field, where they play an important role in maintaining human health and preventing infection. Nonwoven fabrics, also known as non-woven textiles, are composed of oriented or randomly arranged fibers and are called fabrics because they have the appearance and some properties of cloth. They are mostly made from polypropylene granules as raw materials, produced in a continuous one-step process of high-temperature melting, spinning, laying, and hot-pressing. Nonwoven fabrics have no warp or weft threads, making them very convenient to cut and sew. They are also lightweight and easy to shape, making them popular with craft enthusiasts. Nonwoven fabrics break through the traditional textile principles and have the characteristics of short process flow, fast production speed, high output, low cost, wide application, and diverse raw material sources, leading to their widespread use in daily production and life. Our use of nonwoven fabrics permeates almost every corner, and compared with other materials, nonwoven fabrics have advantages such as soft texture, wide availability, good moisture absorption, moderate strength, and low price, making them widely used in the manufacture of disposable medical masks, disposable protective clothing, and so on.

[0003] Because polypropylene is a hydrocarbon material with a low oxygen index, it is easily combustible, resulting in poor flame retardant properties of polypropylene nonwoven fabric. To improve the safety of polypropylene nonwoven fabric, flame retardants are usually added to improve its flame retardant properties.

[0004] Flame retardants are functional additives that impart flame-retardant properties to flammable polymers. They are mainly classified as organic and inorganic, including halogenated flame retardants (organochlorides and organic bromides) and non-halogenated ones. Organic flame retardants are represented by bromine-based, phosphorus-nitrogen-based, nitrogen-based, and red phosphorus compounds, while inorganic ones primarily consist of antimony trioxide, magnesium hydroxide, aluminum hydroxide, and silicon-based flame retardant systems. Among these, halogenated flame retardants, the most commonly used type, possess unparalleled efficiency compared to other flame retardant series; however, their environmental and human health hazards cannot be ignored.

[0005] Chinese patent application number 202110659548.7 discloses a method for preparing an environmentally friendly nonwoven fabric with flame-retardant function. The main technical solution is to simultaneously mix decabromodiphenyl ethane, decabromodiphenyl ether, and antimony trioxide into a nonwoven fabric layer prepared from polyester fibers. Among them, the proportion of decabromodiphenyl ethane in the fiber solution reaches 10%. Although the purpose is to fully disperse the flame retardant in the fiber to improve the dispersion uniformity and thus improve the flame retardant effect, its high bromine content will also cause a large amount of smoke and corrosive toxic products to be generated when combustion occurs. At the same time, according to the conventional understanding of those skilled in the art, the inorganic flame retardant (antimony trioxide) must be added in large quantities to have good flame retardant properties. Such a large amount of addition will inevitably cause a serious reduction in the mechanical properties of the polymer, and its dispersibility is not good enough. This leads to a decrease in the dispersion effect of the three flame retardants, resulting in a decrease in the flame retardant effect. The actual flame retardant application effect is not ideal and it is not suitable for the application of flame-retardant nonwoven fabrics.

[0006] Therefore, developing a nonwoven fabric with good flame retardant and antibacterial properties is of positive significance to the field of textile manufacturing technology. Summary of the Invention

[0007] In view of the shortcomings of the prior art, the purpose of this invention is to provide a flame-retardant and antibacterial nonwoven fabric and its preparation method. The nonwoven fabric has excellent antistatic and flame-retardant properties, while ensuring that the nonwoven fabric has strong mechanical properties, effectively improving the service life of the nonwoven fabric.

[0008] To achieve the above objectives, the present invention provides the following technical solution:

[0009] A flame-retardant and antibacterial nonwoven fabric, comprising the following raw materials by weight:

[0010] 80-100 parts homopolymer polypropylene, 10-20 parts ethylene-propylene copolymer, 0.5-1.5 parts antioxidant, 2-4 parts modified antibacterial agent, 10-20 parts high-density polyethylene, 7-12 parts composite flame retardant, 5-10 parts compatibilizer, and 0.5-1 parts magnesium stearate.

[0011] Preferably, the antioxidant is a mixture of antioxidant 1098 and antioxidant 168 in a mass ratio of 2:1; the compatibilizer is one or more of maleic anhydride-grafted polypropylene and maleic anhydride-grafted polyethylene.

[0012] Preferably, the preparation method of the modified antibacterial agent includes the following steps:

[0013] S1. Add nano-titanium dioxide to sodium hydroxide solution, and then perform hydrothermal reaction at 130℃ for 10-15h. After the reaction is completed, filter, wash with dilute hydrochloric acid and deionized water in sequence until pH is 7, and dry to obtain flake titanium dioxide.

[0014] S2. Add the flake titanium dioxide from step S1 to anhydrous ethanol, then add γ-mercaptopropyltrimethoxysilane, and carry out a constant temperature reaction. After the reaction is completed, filter and dry to obtain mercapto-modified flake titanium dioxide.

[0015] S3. Add the thiolized flake titanium dioxide, hexafluorobutyl acrylate, and azobisisobutyronitrile from step S2 to toluene, and carry out the thiol-alkene reaction under a nitrogen atmosphere. After the reaction is completed, filter, wash, dry, and grind to obtain modified flake titanium dioxide.

[0016] S4. Add the modified flake titanium dioxide obtained in step S3 to toluene, then add epichlorohydrin and 6-guanidinohexanoate, stir and react. After the reaction is complete, filter, wash, dry and grind to obtain the modified antibacterial agent.

[0017] Preferably, in step S1, the concentration of the sodium hydroxide solution is 5-10 mol / L, the mass ratio of the nano-titanium dioxide to the sodium hydroxide solution is 10:150-200, the concentration of the dilute hydrochloric acid is 0.5 mol / L, the mass ratio of the flake-shaped titanium dioxide to γ-mercaptopropyltrimethoxysilane in step S2 is 10:5-15, the temperature of the isothermal reaction is 60-70℃, and the reaction time is 3-5 h.

[0018] Preferably, in step S3, the mass ratio of thiolized flake titanium dioxide, hexafluorobutyl acrylate, and azobisisobutyronitrile is 100:20-40:1-3; the temperature of the thiol-alkene reaction is 90-100℃, and the reaction time is 10-15h; in step S4, the mass ratio of modified flake titanium dioxide, epichlorohydrin, and 6-guanidinohexanoate is 100:30-50:20-30; the temperature of the stirring reaction is 70-80℃, and the reaction time is 3-5h.

[0019] Preferably, the preparation method of the composite flame retardant includes the following steps:

[0020] (a) Add sepiolite to sodium hydroxide solution and soak at room temperature for 3-5 hours. After soaking, filter, wash, dry and calcine to obtain solid powder. Then add solid powder to deionized water, then add ammonium polyphosphate and stir to react. After the reaction is completed, remove deionized water by rotary evaporation to obtain modified sepiolite.

[0021] (b) The modified sepiolite from step (a) was added to anhydrous ethanol, and ammonia was added to adjust the pH to 10. Then, butyl orthosilicate, 3-(2,3-epoxypropoxy)propyltriethoxysilane and deionized water were added and the reaction was carried out at a constant temperature. After the reaction was completed, the mixture was washed, dried, ground and sieved to obtain the composite flame retardant.

[0022] Preferably, the concentration of the sodium hydroxide solution in step (a) is 2-3 mol / L; the calcination temperature is 400-500℃ and the calcination time is 1-2 h; the mass ratio of the solid powder to ammonium polyphosphate is 20:15-25; the stirring reaction temperature is 80-90℃ and the reaction time is 2-4 h.

[0023] Preferably, in step (b), the mass ratio of modified sepiolite, butyl orthosilicate, 3-(2,3-epoxypropoxy)propyltriethoxysilane, and deionized water is 20:10-20:5-10:50-70; the isothermal reaction temperature is 60-70℃, and the reaction time is 4-8h; the drying temperature is 80-100℃, and the drying time is 10-15h.

[0024] This invention also protects a method for preparing the flame-retardant and antibacterial nonwoven fabric, comprising the following steps:

[0025] (1) Weigh the raw materials according to the formula, add homopolymer polypropylene, ethylene propylene copolymer, antioxidant, modified antibacterial agent, high-density polyethylene, composite flame retardant, compatibilizer and magnesium stearate into a high-speed mixer, mix evenly, and then perform intensive mixing and granulation to obtain the mixture masterbatch.

[0026] (2) The mixture masterbatch in step (1) is dried, then melted by screw extrusion, and then filtered, metered, spun, drawn, web formed, hot rolled into fabric, wound, cut and packaged to obtain the flame-retardant and antibacterial nonwoven fabric.

[0027] Preferably, the mixing temperature in step (1) is 170-200℃; the extrusion melting temperature in step (2) is 190-230℃; the spinning process is: the melt is spun through a spinneret at 200-230℃ under a working pressure of 7-8MPa; the web forming process is: the web is formed by airflow stretching under an air temperature of 10-20℃ and an air pressure of 1.0-2.0KPa; the hot-rolling fabric forming process is: the fabric is formed by hot rolling under a temperature of 90-105℃ and a pressure of 8-10MPa.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] (1) The flame-retardant and antibacterial nonwoven fabric provided by the present invention modifies nano titanium dioxide and adds it to the raw materials as an antibacterial agent, which not only improves the antibacterial properties of the nonwoven fabric, but also has a synergistic effect with the composite flame retardant to improve the flame retardancy of the nonwoven fabric. Titanium dioxide itself can be used as an antibacterial agent and has good and stable bactericidal function, but it can only play a catalytic antibacterial role under ultraviolet light. This invention first obtains sheet-like titanium dioxide from nano-titanium dioxide via a hydrothermal method. The sheet-like structure can both block the migration of flammable small molecules generated during polymer chain combustion to the combustion interface and slow down the migration of external oxygen into the polymer interior. It can also synergistically interact with composite flame retardants to improve the flame retardant performance of the system. Subsequently, the sheet-like titanium dioxide is reacted with γ-mercaptopropyltrimethoxysilane to mercapto-modify its surface, enhancing its reactivity. Next, the mercapto-modified sheet-like titanium dioxide undergoes a mercapto-olefin reaction with hexafluorobutyl acrylate and azobisisobutyronitrile to graft fluorine-containing groups onto the titanium dioxide surface, improving its affinity for polymers. The previous compatibility was addressed; finally, the modified flake titanium dioxide was reacted with epichlorohydrin and 6-guanidinohexanoate to graft guanidino groups onto the surface of the titanium dioxide. Guanidino groups achieve the final bactericidal purpose through electrostatic attraction with the cell membrane. Guanidino groups are easily adsorbed and penetrate into microorganisms, disrupting their metabolism and killing or inhibiting them. Therefore, this solves the problem that titanium dioxide can only exert its catalytic antibacterial effect under ultraviolet light. At the same time, the introduction of fluorine-containing groups that migrate to the surface during subsequent nonwoven fabric processing can increase the guanidino group content on the nonwoven fabric surface, greatly improving the utilization rate of guanidino groups and giving the nonwoven fabric better antibacterial properties.

[0030] (2) The flame-retardant and antibacterial nonwoven fabric provided by the present invention is modified with sepiolite. Sepiolite has zeolite water channels that run through the entire clay structure and a huge specific surface area. This structure gives it excellent barrier properties and can be used as a highly efficient and environmentally friendly flame-retardant additive. First, the sepiolite is treated with alkali to remove surface impurities. Then, it is calcined to expand its internal pores and improve its adsorption capacity, which is conducive to the subsequent entry of ammonium polyphosphate into the internal pores of the sepiolite. Then, the ammonium polyphosphate is coated with sepiolite. The ammonium polyphosphate decomposes into polyphosphoric acid when heated. As the temperature rises, the polyphosphoric acid continues to decompose into metaphosphoric acid and pyrophosphoric acid, and finally decomposes into P2O5 and phosphoric acid compounds, which cover the surface of the nonwoven fabric to dehydrate and carbonize it, forming a dense and flame-retardant carbon layer to prevent the nonwoven fabric from melting and dripping when heated. The char layer prevents the spread of fire caused by falling or flowing material. Simultaneously, it isolates flammable gases generated from the thermal decomposition of the material from contact with air, preventing the combustion reaction. Subsequently, modified sepiolite is reacted with butyl orthosilicate and 3-(2,3-epoxypropoxy)propyltriethoxysilane to prepare silica gel and polysiloxane-coated sepiolite via a sol-gel method. This improves the compatibility of sepiolite with polypropylene, making it less likely to migrate from the polymer matrix to the surface, thus enhancing the flame retardancy of the nonwoven fabric. Furthermore, the silica gel and polysiloxane, along with ammonium polyphosphate, exert a PN-Si synergistic flame-retardant effect, further improving the polymer's flame-retardant properties. During combustion, sepiolite also exhibits high adsorption capacity; its structure contains numerous pores that effectively adsorb smoke, thereby reducing smoke release.

[0031] (3) The flame-retardant and antibacterial nonwoven fabric provided by the present invention has excellent antibacterial and flame-retardant properties. At the same time, the addition of high-density polyethylene can effectively improve the toughness of the nonwoven fabric. Furthermore, the addition of ethylene-propylene copolymer and compatibility can improve the compatibility between polypropylene and high-density polyethylene, so that the prepared nonwoven fabric has better mechanical properties and good application prospects. Detailed Implementation

[0032] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. 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.

[0033] The homopolymer polypropylene is Sinopec S2040; the ethylene-propylene copolymer is LG R6400 (Korea); the high-density polyethylene is PetroChina 5000S; the nano-titanium dioxide is purchased from Bohuas Nanotechnology (Ningbo) Co., Ltd., with an average particle size of 50 nm; the sepiolite is purchased from Lingshou County Maozhuo Building Materials Co., Ltd., with a mesh size of 600 mesh; and the ammonium polyphosphate is purchased from Shandong Jinghao Chemical Co., Ltd., with CAS number 68333-79-9.

[0034] Example 1

[0035] A flame-retardant and antibacterial nonwoven fabric, comprising the following raw materials:

[0036] 1 kg of homopolymer polypropylene, 200 g of ethylene-propylene copolymer, 15 g of antioxidant, 40 g of modified antibacterial agent, 200 g of high-density polyethylene, 120 g of composite flame retardant, 100 g of maleic anhydride-grafted polypropylene, and 10 g of magnesium stearate.

[0037] The antioxidant is a mixture of antioxidant 1098 and antioxidant 168 in a mass ratio of 2:1.

[0038] The preparation method of the modified antibacterial agent includes the following steps:

[0039] S1. Add 10g of nano titanium dioxide to 200g of sodium hydroxide solution with a concentration of 10mol / L, and then perform a hydrothermal reaction at 130℃ for 15h. After the reaction is completed, filter the solution and wash it with 0.5mol / L dilute hydrochloric acid and deionized water until the pH reaches 7. Dry the solution to obtain flake titanium dioxide.

[0040] S2. Add 10g of the flake titanium dioxide from step S1 to 200mL of anhydrous ethanol, then add 15g of γ-mercaptopropyltrimethoxysilane, and react at 70℃ for 3h. After the reaction is complete, filter and dry to obtain mercapto-modified flake titanium dioxide.

[0041] S3. Add 100g of thiolized flake titanium dioxide, 40g of hexafluorobutyl acrylate and 3g of azobisisobutyronitrile from step S2 to 600mL of toluene, and carry out the thiol-alkene reaction under a nitrogen atmosphere at a reaction temperature of 100℃ for 10h. After the reaction is completed, filter, wash, dry and grind to obtain modified flake titanium dioxide.

[0042] S4. Add 100g of the modified flake titanium dioxide obtained in step S3 to 700mL of toluene, then add 50g of epichlorohydrin and 30g of 6-guanidinohexanoate salt, stir and react at 80℃ for 3h. After the reaction is completed, filter, wash, dry and grind to obtain the modified antibacterial agent.

[0043] The preparation method of the composite flame retardant includes the following steps:

[0044] (a) 100g of sepiolite was added to 500mL of sodium hydroxide solution with a concentration of 3mol / L and impregnated at room temperature for 3h. After impregnation, the solution was filtered, washed, and dried. The solution was then calcined at 500℃ for 1h to obtain solid powder. Subsequently, 20g of the solid powder was added to 200mL of deionized water, and then 25g of ammonium polyphosphate was added. The mixture was stirred and reacted at 90℃ for 2h. After the reaction was completed, the deionized water was removed by rotary evaporation to obtain modified sepiolite.

[0045] (b) Add the modified sepiolite (20g) from step (a) to 300mL of anhydrous ethanol, add 5% ammonia water to adjust the pH to 10, then add 20g of butyl orthosilicate, 10g of 3-(2,3-epoxypropoxy)propyltriethoxysilane and 70g of deionized water, and react at 70°C for 4h. After the reaction is complete, wash, dry at 100°C for 10h, then ball mill, and pass through a 200-mesh sieve to obtain the composite flame retardant.

[0046] A method for preparing a flame-retardant and antibacterial nonwoven fabric includes the following steps:

[0047] (1) Weigh the raw materials according to the formula, add homopolymer polypropylene, ethylene propylene copolymer, antioxidant, modified antibacterial agent, high-density polyethylene, composite flame retardant, maleic anhydride grafted polypropylene and magnesium stearate into a high-speed mixer, mix evenly, and then carry out intensive mixing and granulation. The intensive mixing temperature is 200℃ to obtain the mixture masterbatch.

[0048] (2) The mixture masterbatch in step (1) is dried, then melted by screw extrusion at a temperature of 230°C, and then filtered, metered, spun, drawn, web formed, hot rolled into fabric, wound, cut and packaged to obtain the flame-retardant and antibacterial nonwoven fabric.

[0049] The spinning process in step (2) is as follows: the melt is spun through a spinneret at 230°C under a working pressure of 7 MPa; the web forming process is as follows: the web is formed by airflow stretching under a wind temperature of 10°C and a wind pressure of 2.0 kPa; the hot-rolled fabric forming process is as follows: the fabric is formed by hot rolling under a temperature of 105°C and a pressure of 8 MPa.

[0050] Example 2

[0051] A flame-retardant and antibacterial nonwoven fabric, comprising the following raw materials:

[0052] Homopolymer polypropylene 0.9kg, ethylene-propylene copolymer 150g, antioxidant 10g, modified antibacterial agent 30g, high-density polyethylene 150g, composite flame retardant 100g, maleic anhydride grafted polypropylene 80g, magnesium stearate 8g.

[0053] The antioxidant is a mixture of antioxidant 1098 and antioxidant 168 in a mass ratio of 2:1.

[0054] The preparation method of the modified antibacterial agent includes the following steps:

[0055] S1. Add 10g of nano titanium dioxide to 200g of sodium hydroxide solution with a concentration of 5mol / L, and then perform hydrothermal reaction at 130℃ for 13h. After the reaction is completed, filter and wash with 0.5mol / L dilute hydrochloric acid and deionized water until the pH is 7. Dry to obtain flake titanium dioxide.

[0056] S2. Add 10g of the flake titanium dioxide from step S1 to 200mL of anhydrous ethanol, then add 10g of γ-mercaptopropyltrimethoxysilane, and react at 65℃ for 4h. After the reaction is complete, filter and dry to obtain mercapto-modified flake titanium dioxide.

[0057] S3. Add 100g of thiolized flake titanium dioxide, 30g of hexafluorobutyl acrylate and 2g of azobisisobutyronitrile from step S2 to 600mL of toluene, and carry out the thiol-alkene reaction under a nitrogen atmosphere at a reaction temperature of 95℃ for 13h. After the reaction is completed, filter, wash, dry and grind to obtain modified flake titanium dioxide.

[0058] S4. Add the modified flake titanium dioxide (100g) obtained in step S3 to 700mL of toluene, then add 40g of epichlorohydrin and 25g of 6-guanidinohexanoate salt, stir and react at 75℃ for 4h. After the reaction is completed, filter, wash, dry and grind to obtain the modified antibacterial agent.

[0059] The preparation method of the composite flame retardant includes the following steps:

[0060] (a) 100g of sepiolite was added to 500mL of sodium hydroxide solution with a concentration of 2mol / L and impregnated at room temperature for 4h. After impregnation, the solution was filtered, washed, and dried. The solution was then calcined at 450℃ for 1.5h to obtain solid powder. Subsequently, 20g of the solid powder was added to 200mL of deionized water, followed by 20g of ammonium polyphosphate. The mixture was stirred and reacted at 85℃ for 3h. After the reaction was completed, the deionized water was removed by rotary evaporation to obtain modified sepiolite.

[0061] (b) The modified sepiolite (20g) from step (a) was added to 300mL of anhydrous ethanol, and 5% ammonia was added to adjust the pH to 10. Then 15g of butyl orthosilicate, 8g of 3-(2,3-epoxypropoxy)propyltriethoxysilane and 60g of deionized water were added. The mixture was reacted at 65°C for 6h. After the reaction was completed, the mixture was washed and dried at 90°C for 13h. Then it was ball-milled and passed through a 200-mesh sieve to obtain the composite flame retardant.

[0062] A method for preparing a flame-retardant and antibacterial nonwoven fabric includes the following steps:

[0063] (1) Weigh the raw materials according to the formula, add homopolymer polypropylene, ethylene propylene copolymer, antioxidant, modified antibacterial agent, high-density polyethylene, composite flame retardant, maleic anhydride grafted polypropylene and magnesium stearate into a high-speed mixer, mix evenly, and then carry out intensive mixing and granulation. The intensive mixing temperature is 190℃ to obtain the mixture masterbatch.

[0064] (2) The mixture masterbatch in step (1) is dried, then melted by screw extrusion at a temperature of 210°C, and then filtered, metered, spun, drawn, web formed, hot rolled into fabric, wound, cut and packaged to obtain the flame-retardant and antibacterial nonwoven fabric.

[0065] The spinning process in step (2) is as follows: the melt is spun through a spinneret at 220°C under a working pressure of 8 MPa; the web forming process is as follows: the web is formed by airflow stretching under a wind temperature of 15°C and a wind pressure of 2.0 kPa; the hot-rolled fabric forming process is as follows: the fabric is formed by hot rolling under a temperature of 100°C and a pressure of 9 MPa.

[0066] Example 3

[0067] A flame-retardant and antibacterial nonwoven fabric, comprising the following raw materials:

[0068] 0.8 kg of homopolymer polypropylene, 100 g of ethylene-propylene copolymer, 5 g of antioxidant, 20 g of modified antibacterial agent, 100 g of high-density polyethylene, 70 g of composite flame retardant, 50 g of maleic anhydride-grafted polyethylene, and 5 g of magnesium stearate.

[0069] The antioxidant is a mixture of antioxidant 1098 and antioxidant 168 in a mass ratio of 2:1.

[0070] The preparation method of the modified antibacterial agent includes the following steps:

[0071] S1. Add 10g of nano titanium dioxide to 150g of sodium hydroxide solution with a concentration of 5mol / L, and then perform a hydrothermal reaction at 130℃ for 10h. After the reaction is completed, filter the solution and wash it with 0.5mol / L dilute hydrochloric acid and deionized water until the pH reaches 7. Dry the solution to obtain flake titanium dioxide.

[0072] S2. Add 10g of the flake titanium dioxide from step S1 to 200mL of anhydrous ethanol, then add 5g of γ-mercaptopropyltrimethoxysilane, and react at 60℃ for 5h. After the reaction is complete, filter and dry to obtain mercapto-modified flake titanium dioxide.

[0073] S3. Add 100g of thiolized flake titanium dioxide, 20g of hexafluorobutyl acrylate and 1g of azobisisobutyronitrile from step S2 to 600mL of toluene, and carry out the thiol-alkene reaction under a nitrogen atmosphere at a reaction temperature of 90℃ for 15h. After the reaction is completed, filter, wash, dry and grind to obtain modified flake titanium dioxide.

[0074] S4. Add 100g of the modified flake titanium dioxide obtained in step S3 to 700mL of toluene, then add 30g of epichlorohydrin and 20g of 6-guanidinohexanoate salt, stir and react at 70℃ for 5h. After the reaction is completed, filter, wash, dry and grind to obtain the modified antibacterial agent.

[0075] The preparation method of the composite flame retardant includes the following steps:

[0076] (a) 100g of sepiolite was added to 500mL of sodium hydroxide solution with a concentration of 2mol / L and impregnated at room temperature for 5h. After impregnation, the solution was filtered, washed, dried, and calcined at 400℃ for 2h to obtain solid powder. Then, 20g of solid powder was added to 200mL of deionized water, followed by 15g of ammonium polyphosphate. The mixture was stirred and reacted at 80℃ for 4h. After the reaction was completed, the deionized water was removed by rotary evaporation to obtain modified sepiolite.

[0077] (b) Add the modified sepiolite (20g) from step (a) to 300mL of anhydrous ethanol, add 5% ammonia water to adjust the pH to 10, then add 10g of butyl orthosilicate, 5g of 3-(2,3-epoxypropoxy)propyltriethoxysilane and 50g of deionized water, and react at 60℃ for 8h. After the reaction is completed, wash and dry at 80℃ for 15h, then ball mill and pass through a 200-mesh sieve to obtain the composite flame retardant.

[0078] A method for preparing a flame-retardant and antibacterial nonwoven fabric includes the following steps:

[0079] (1) Weigh the raw materials according to the formula, add homopolymer polypropylene, ethylene propylene copolymer, antioxidant, modified antibacterial agent, high-density polyethylene, composite flame retardant, maleic anhydride grafted polyethylene, and magnesium stearate into a high-speed mixer, mix evenly, and then carry out intensive mixing and granulation. The intensive mixing temperature is 170℃ to obtain the mixture masterbatch.

[0080] (2) The mixture masterbatch in step (1) is dried, then melted by screw extrusion at a temperature of 190°C, and then filtered, metered, spun, drawn, web formed, hot rolled into fabric, wound, cut and packaged to obtain the flame-retardant and antibacterial nonwoven fabric.

[0081] The spinning process in step (2) is as follows: the melt is spun through a spinneret at 200°C under a working pressure of 8 MPa; the web forming process is as follows: the web is formed by airflow stretching under a wind temperature of 20°C and a wind pressure of 1.0 kPa; the hot-rolled fabric forming process is as follows: the fabric is formed by hot rolling under a temperature of 90°C and a pressure of 10 MPa.

[0082] Comparative Example 1

[0083] A flame-retardant and antibacterial nonwoven fabric, comprising the following raw materials:

[0084] 1 kg of homopolymer polypropylene, 200 g of ethylene-propylene copolymer, 15 g of antioxidant, 40 g of nano titanium dioxide, 200 g of high-density polyethylene, 120 g of composite flame retardant, 100 g of maleic anhydride-grafted polypropylene, and 10 g of magnesium stearate.

[0085] The antioxidant is a mixture of antioxidant 1098 and antioxidant 168 in a mass ratio of 2:1.

[0086] The preparation method of the composite flame retardant includes the following steps:

[0087] (a) 100g of sepiolite was added to 500mL of sodium hydroxide solution with a concentration of 3mol / L and impregnated at room temperature for 3h. After impregnation, the solution was filtered, washed, and dried. The solution was then calcined at 500℃ for 1h to obtain solid powder. Subsequently, 20g of the solid powder was added to 200mL of deionized water, and then 25g of ammonium polyphosphate was added. The mixture was stirred and reacted at 90℃ for 2h. After the reaction was completed, the deionized water was removed by rotary evaporation to obtain modified sepiolite.

[0088] (b) Add the modified sepiolite (20g) from step (a) to 300mL of anhydrous ethanol, add 5% ammonia water to adjust the pH to 10, then add 20g of butyl orthosilicate, 10g of 3-(2,3-epoxypropoxy)propyltriethoxysilane and 70g of deionized water, and react at 70°C for 4h. After the reaction is complete, wash, dry at 100°C for 10h, then ball mill, and pass through a 200-mesh sieve to obtain the composite flame retardant.

[0089] A method for preparing a flame-retardant and antibacterial nonwoven fabric includes the following steps:

[0090] (1) Weigh the raw materials according to the formula, add homopolymer polypropylene, ethylene propylene copolymer, antioxidant, nano titanium dioxide, high-density polyethylene, composite flame retardant, maleic anhydride grafted polypropylene and magnesium stearate into a high-speed mixer, mix evenly, and then carry out intensive mixing and granulation. The intensive mixing temperature is 200℃ to obtain the mixture masterbatch.

[0091] (2) The mixture masterbatch in step (1) is dried, then melted by screw extrusion at a temperature of 230°C, and then filtered, metered, spun, drawn, web formed, hot rolled into fabric, wound, cut and packaged to obtain the flame-retardant and antibacterial nonwoven fabric.

[0092] The spinning process in step (2) is as follows: the melt is spun through a spinneret at 230°C under a working pressure of 7 MPa; the web forming process is as follows: the web is formed by airflow stretching under a wind temperature of 10°C and a wind pressure of 2.0 kPa; the hot-rolled fabric forming process is as follows: the fabric is formed by hot rolling under a temperature of 105°C and a pressure of 8 MPa.

[0093] Comparative Example 2

[0094] A flame-retardant and antibacterial nonwoven fabric, comprising the following raw materials:

[0095] 1 kg of homopolymer polypropylene, 200 g of ethylene-propylene copolymer, 15 g of antioxidant, 40 g of modified antibacterial agent, 200 g of high-density polyethylene, 120 g of sepiolite, 100 g of maleic anhydride-grafted polypropylene, and 10 g of magnesium stearate.

[0096] The antioxidant is a mixture of antioxidant 1098 and antioxidant 168 in a mass ratio of 2:1.

[0097] The preparation method of the modified antibacterial agent includes the following steps:

[0098] S1. Add 10g of nano titanium dioxide to 200g of sodium hydroxide solution with a concentration of 10mol / L, and then perform a hydrothermal reaction at 130℃ for 15h. After the reaction is completed, filter the solution and wash it with 0.5mol / L dilute hydrochloric acid and deionized water until the pH reaches 7. Dry the solution to obtain flake titanium dioxide.

[0099] S2. Add 10g of the flake titanium dioxide from step S1 to 200mL of anhydrous ethanol, then add 15g of γ-mercaptopropyltrimethoxysilane, and react at 70℃ for 3h. After the reaction is complete, filter and dry to obtain mercapto-modified flake titanium dioxide.

[0100] S3. Add 100g of thiolized flake titanium dioxide, 40g of hexafluorobutyl acrylate and 3g of azobisisobutyronitrile from step S2 to 600mL of toluene, and carry out the thiol-alkene reaction under a nitrogen atmosphere at a reaction temperature of 100℃ for 10h. After the reaction is completed, filter, wash, dry and grind to obtain modified flake titanium dioxide.

[0101] S4. Add 100g of the modified flake titanium dioxide obtained in step S3 to 700mL of toluene, then add 50g of epichlorohydrin and 30g of 6-guanidinohexanoate salt, stir and react at 80℃ for 3h. After the reaction is completed, filter, wash, dry and grind to obtain the modified antibacterial agent.

[0102] A method for preparing a flame-retardant and antibacterial nonwoven fabric includes the following steps:

[0103] (1) Weigh the raw materials according to the formula, add homopolymer polypropylene, ethylene propylene copolymer, antioxidant, modified antibacterial agent, high-density polyethylene, sepiolite, maleic anhydride grafted polypropylene and magnesium stearate into a high-speed mixer, mix evenly, and then carry out intensive mixing and granulation. The intensive mixing temperature is 200℃ to obtain the mixture masterbatch.

[0104] (2) The mixture masterbatch in step (1) is dried, then melted by screw extrusion at a temperature of 230°C, and then filtered, metered, spun, drawn, web formed, hot rolled into fabric, wound, cut and packaged to obtain the flame-retardant and antibacterial nonwoven fabric.

[0105] The spinning process in step (2) is as follows: the melt is spun through a spinneret at 230°C under a working pressure of 7 MPa; the web forming process is as follows: the web is formed by airflow stretching under a wind temperature of 10°C and a wind pressure of 2.0 kPa; the hot-rolled fabric forming process is as follows: the fabric is formed by hot rolling under a temperature of 105°C and a pressure of 8 MPa.

[0106] 1. Antibacterial test

[0107] The flame-retardant and antibacterial nonwoven fabrics prepared in Examples 1-3 and Comparative Examples 1-2 were tested for antibacterial properties according to GB / T 20944.3-2008 "Antibacterial Performance Testing" and after being washed 50 times with standard water. The test strain was Escherichia coli ATTC8739. The test results are shown in Table 1 below.

[0108] Table 1

[0109] Example 1 99.92 96.86 Example 2 99.76 95.97 Example 3 99.18 95.72 Comparative Example 1 63.91 50.74 Comparative Example 2 98.42 94.69

[0110] As shown in Table 1, the flame-retardant and antibacterial nonwoven fabric prepared by the present invention has good antibacterial properties and antibacterial durability. After 50 washes, the antibacterial rate of the nonwoven fabric still reaches more than 95.72%, indicating that the antibacterial properties are durable.

[0111] 2. Flame retardant performance and mechanical property testing

[0112] The flame-retardant and antibacterial nonwoven fabrics prepared in Examples 1-3 and Comparative Examples 1-2 were tested for flame retardant performance and tensile strength. The limiting oxygen index was tested on an oxygen index tester according to GB / T 8624-2012 "Classification of Burning Performance of Building Materials and Products". The sample size was 150mm×85mm. The higher the limiting oxygen index value, the better the flame retardant performance. The tensile strength was tested according to GB / T 24218.3-2010 "Test Methods for Nonwoven Fabrics". The sample size was 50mm wide and 200mm long. The sample was stretched at a constant elongation rate of 100mm / min until it broke. The test results are shown in Table 2 below.

[0113] Table 2

[0114] Example 1 63 33.6 46.8 23.7 Example 2 65 33.2 45.2 22.9 Example 3 62 32.7 44.7 22.3 Comparative Example 1 60 29.8 42.5 19.6 Comparative Example 2 66 23.5 40.3 17.8

[0115] As can be seen from Table 2, the flame-retardant and antibacterial nonwoven fabric prepared by the present invention has excellent flame-retardant properties, with a limiting oxygen index of up to 33.6. Compared with Comparative Example 1 and Comparative Example 2, its mechanical properties are also slightly improved, showing good application prospects.

[0116] 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 flame-retardant and antibacterial nonwoven fabric, characterized in that, By weight, it includes the following ingredients: 80-100 parts homopolymer polypropylene, 10-20 parts ethylene-propylene copolymer, 0.5-1.5 parts antioxidant, 2-4 parts modified antibacterial agent, 10-20 parts high-density polyethylene, 7-12 parts composite flame retardant, 5-10 parts compatibilizer, and 0.5-1 parts magnesium stearate. The preparation method of the modified antibacterial agent includes the following steps: S1. Add nano-titanium dioxide to sodium hydroxide solution, and then perform hydrothermal reaction at 130℃ for 10-15h. After the reaction is completed, filter, wash with dilute hydrochloric acid and deionized water in sequence until pH is 7, and dry to obtain flake titanium dioxide. S2. Add the flake titanium dioxide from step S1 to anhydrous ethanol, then add γ-mercaptopropyltrimethoxysilane, and carry out a constant temperature reaction. After the reaction is completed, filter and dry to obtain mercapto-modified flake titanium dioxide. S3. Add the thiolized flake titanium dioxide, hexafluorobutyl acrylate, and azobisisobutyronitrile from step S2 to toluene, and carry out the thiol-alkene reaction under a nitrogen atmosphere. After the reaction is completed, filter, wash, dry, and grind to obtain modified flake titanium dioxide. S4. Add the modified flake titanium dioxide obtained in step S3 to toluene, then add epichlorohydrin and 6-guanidinohexanoate salt, stir and react. After the reaction is completed, filter, wash, dry and grind to obtain the modified antibacterial agent. The preparation method of the composite flame retardant includes the following steps: (a) Add sepiolite to sodium hydroxide solution and soak at room temperature for 3-5 hours. After soaking, filter, wash, dry and calcine to obtain solid powder. Then add solid powder to deionized water, then add ammonium polyphosphate and stir to react. After the reaction is completed, remove deionized water by rotary evaporation to obtain modified sepiolite. (b) The modified sepiolite from step (a) was added to anhydrous ethanol, and ammonia was added to adjust the pH to 10. Then, butyl orthosilicate, 3-(2,3-epoxypropoxy)propyltriethoxysilane and deionized water were added and reacted at a constant temperature. After the reaction was completed, the mixture was washed, dried, ball-milled and sieved to obtain the composite flame retardant.

2. The flame-retardant and antibacterial nonwoven fabric according to claim 1, characterized in that, The antioxidant is a mixture of antioxidant 1098 and antioxidant 168 in a mass ratio of 2:1; the compatibilizer is one or more of maleic anhydride-grafted polypropylene and maleic anhydride-grafted polyethylene.

3. The flame-retardant and antibacterial nonwoven fabric according to claim 1, characterized in that, In step S1, the concentration of the sodium hydroxide solution is 5-10 mol / L, and the mass ratio of the nano-titanium dioxide to the sodium hydroxide solution is 10:150-200; the concentration of the dilute hydrochloric acid is 0.5 mol / L; in step S2, the mass ratio of the flake-shaped titanium dioxide to γ-mercaptopropyltrimethoxysilane is 10:5-15, the temperature of the isothermal reaction is 60-70℃, and the reaction time is 3-5 h.

4. The flame-retardant and antibacterial nonwoven fabric according to claim 1, characterized in that, In step S3, the mass ratio of thiolized flake titanium dioxide, hexafluorobutyl acrylate, and azobisisobutyronitrile is 100:20-40:1-3; the temperature of the thiol-alkene reaction is 90-100℃, and the reaction time is 10-15h; in step S4, the mass ratio of modified flake titanium dioxide, epichlorohydrin, and 6-guanidinohexanoate is 100:30-50:20-30; the temperature of the stirring reaction is 70-80℃, and the reaction time is 3-5h.

5. The flame-retardant and antibacterial nonwoven fabric according to claim 1, characterized in that, The concentration of the sodium hydroxide solution in step (a) is 2-3 mol / L; the calcination temperature is 400-500℃ and the calcination time is 1-2 h; the mass ratio of the solid powder to ammonium polyphosphate is 20:15-25; the stirring reaction temperature is 80-90℃ and the reaction time is 2-4 h.

6. The flame-retardant and antibacterial nonwoven fabric according to claim 1, characterized in that, In step (b), the mass ratio of modified sepiolite, butyl orthosilicate, 3-(2,3-epoxypropoxy)propyltriethoxysilane, and deionized water is 20:10-20:5-10:50-70; the isothermal reaction temperature is 60-70℃, and the reaction time is 4-8h; the drying temperature is 80-100℃, and the drying time is 10-15h.

7. A method for preparing a flame-retardant and antibacterial nonwoven fabric as described in any one of claims 1-6, characterized in that, Includes the following steps: (1) Weigh the raw materials according to the formula, add homopolymer polypropylene, ethylene propylene copolymer, antioxidant, modified antibacterial agent, high-density polyethylene, composite flame retardant, compatibilizer and magnesium stearate into a high-speed mixer, mix evenly, and then perform intensive mixing and granulation to obtain the mixture masterbatch. (2) The mixture masterbatch in step (1) is dried, then melted by screw extrusion, and then filtered, metered, spun, drawn, web formed, hot rolled into fabric, wound, cut and packaged to obtain the flame-retardant and antibacterial nonwoven fabric.

8. The method for preparing the flame-retardant and antibacterial nonwoven fabric according to claim 7, characterized in that, The mixing temperature in step (1) is 170-200℃; the extrusion melting temperature in step (2) is 190-230℃; the spinning process is: the melt is spun through a spinneret at 200-230℃ under a working pressure of 7-8MPa; the web forming process is: the web is formed by airflow stretching under a wind temperature of 10-20℃ and a wind pressure of 1.0-2.0KPa; the hot-rolled fabric forming process is: the fabric is formed by hot rolling under a temperature of 90-105℃ and a pressure of 8-10MPa.