Natural plant-based antibacterial sanitary napkin surface material and sanitary napkin

Abstract

The present invention discloses a natural plant-based antibacterial sanitary napkin surface material and a sanitary napkin, and relates to the field of fabrics. When preparing the natural plant-based antibacterial sanitary napkin surface material, the present invention first reacts bamboo pulp fiber pretreated with 3-chloropropyltriethoxysilane with benzimidazole-1-acetic acid, and then undergoes amidation and sodium hypobromite degradation to obtain modified bamboo pulp fiber; secondly, hemp fiber is grafted with an initiator to initiate polymerization of acrylamide and N-isopropylacrylamide to obtain modified hemp fiber; finally, the modified bamboo pulp fiber and the modified hemp fiber are subjected to cleaning, carding, web laying, hydroentanglement, degreasing, bleaching, and finishing with a finishing agent to obtain the natural plant-based antibacterial sanitary napkin surface material. The natural plant-based antibacterial sanitary napkin surface material prepared by the present invention has excellent antibacterial and anti-rewetting properties.

Description

Technical Field

[0001] The invention relates to the technical field of fabrics, in particular to a natural plant-based antibacterial sanitary napkin surface material and a sanitary napkin. Background Art

[0002] Sanitary napkins are personal hygiene products used by women during menstruation. They are typically made of multiple layers of material, typically consisting of a top layer, an absorbent layer, a drainage layer, and a base layer. These layers effectively absorb and lock in menstrual blood while keeping the skin dry and comfortable. The top layer, as the part of the sanitary napkin that comes in direct contact with the skin, is crucially important. It must not only be skin-friendly and breathable, but also possess certain hygroscopic and antibacterial properties to reduce bacterial growth and maintain the health of the intimate area.

[0003] Traditional sanitary napkins are mostly made of chemical fiber nonwovens or cotton. While these materials have some performance in terms of moisture absorption and breathability, they lack antibacterial properties. In recent years, with increasing consumer awareness of health and environmental protection, natural plant-based fibers such as bamboo pulp and hemp have gradually become the preferred surface materials. Bamboo pulp, with its excellent moisture absorption and breathability, as well as its natural antibacterial and antimicrobial properties, can effectively reduce bacterial growth and keep private areas clean. Hemp fiber, with its moisture absorption, breathability, comfort, mildew resistance, and antibacterial properties, is considered the most promising green fiber of the 21st century, a kind of second skin for humankind.

[0004] Therefore, to meet market demand for healthier and more environmentally friendly sanitary napkins, it is particularly important to develop a sanitary napkin surface material based on natural plant-based fibers, such as bamboo pulp or hemp, that combines antibacterial and anti-osmosis properties. This new surface material not only significantly improves the comfort and healthiness of sanitary napkins, but also effectively reduces the risk of infection in the private area, providing women with a safer and healthier menstrual care experience. Summary of the Invention

[0005] The purpose of the present invention is to provide a natural plant-based antibacterial sanitary napkin surface material to solve the problems existing in the prior art.

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0007] A natural plant-based antibacterial sanitary napkin surface material is prepared by cleaning, carding, laying, spunlacing, degreasing, bleaching, and finishing with a finishing agent of modified bamboo pulp fiber and modified hemp fiber.

[0008] As an optimization, the modified bamboo pulp fiber is obtained by reacting pretreated bamboo pulp fiber with benzimidazole-1-acetic acid, and then undergoing amidation and sodium hypobromite degradation.

[0009] As an optimization, the modified hemp fiber is obtained by polymerizing acrylamide and N-isopropylacrylamide initiated by a hemp fiber grafting initiator.

[0010] As an optimization, the finishing agent comprises sodium alginate and benzimidazole quaternary ammonium salt.

[0011] A method for preparing a natural plant-based antibacterial sanitary napkin surface material comprises the following steps:

[0012] (1) Pretreated bamboo pulp fiber, benzimidazole-1-acetic acid, potassium iodide, and acetonitrile were mixed in a mass ratio of 1:(0.5-0.7):(0.2-0.3):(20-30), heated to 90-95°C, reacted for 6-8h, filtered, washed with pure water 3-4 times, and vacuum dried at 60°C to obtain pre-modified bamboo pulp fiber;

[0013] (2) Pre-modified bamboo pulp fiber, thionyl chloride, and N,N-dimethylformamide are mixed in a mass ratio of 1:(10-12):(0.1-0.2), heated to 75-80°C and refluxed for 30-40 minutes, filtered after the reaction, and dichloromethane (10-12 times the mass of the pre-modified bamboo pulp fiber) and 25wt% ammonia saturated with ammonium carbonate (2-3 times the mass of the pre-modified bamboo pulp fiber) are added, reacted at room temperature for 20-30 minutes, filtered, washed with pure water 3-4 times, and vacuum dried at 60°C to obtain amidated bamboo pulp fiber; at -5-0°C, amidated bamboo pulp fiber, sodium hypobromite solution, and 4mol / L sodium hydroxide solution are mixed in a mass ratio of 1:(5-7):(0.6-0.7) and ultrasonicated for 10 minutes, then heated to 75-80°C, reacted for 1 hour, filtered, washed with pure water 3-4 times, and vacuum dried at 60°C to obtain modified bamboo pulp fiber;

[0014] (3) Weigh bromoisobutyryl bromide and pyridine in a molar ratio of 1:1, mix bromoisobutyryl bromide, pyridine, and dichloromethane 10-12 times the mass of pyridine, add hemp fiber 2-3 times the mass of pyridine, react at room temperature for 4 hours, filter and wash 4 times with ethanol to obtain pretreated hemp fiber; mix pretreated hemp fiber, N,N-dimethylformamide, cuprous bromide, pentamethyldiethylenetriamine, acrylamide, and N-isopropylacrylamide in a mass ratio of 1:(20-30):(0.1-0.2):(0.01-0.02):(0.2-0.3):(0.2-0.3), react at 60°C for 4 hours, filter and wash 4 times with ethanol, and vacuum dry at 60°C to obtain modified hemp fiber;

[0015] (4) The modified bamboo pulp fiber and the modified hemp fiber are opened and combed respectively, and the modified bamboo pulp fiber and the modified hemp fiber are laid on a net at a mass ratio of 1: (0.8-1.2), so that the modified bamboo pulp fiber is on the lower layer and the modified hemp fiber is on the upper layer, with a surface density of 40-60 g / m 2 , the fabric is subjected to hydroentanglement reinforcement treatment in a hydroentanglement machine, the hydroentanglement pressure of the hydroentanglement machine is 40-50MPa, the screen conveying speed is 4m / min, the water needle distance is 14mm, the water spray hole diameter is 0.2mm, and then the fabric is degreased and bleached to obtain the grey fabric;

[0016] (5) At 70-80° C., formaldehyded sodium alginate, benzimidazole quaternary ammonium salt, and pure water are mixed in a mass ratio of 1:(2-3):(20-30) to obtain a finishing agent solution, and the solution is added to the grey fabric, wherein the mass ratio of the grey fabric to the finishing solution is 1:(20-30). After immersion for 20-30 minutes, the solution is immersed and rolled, the immersion and rolling temperature is 60-70° C., the rolling rate is 100%-120%, and the solution is pre-dried at 60-70° C. for 2-3 minutes. The solution is dried at room temperature to obtain a natural plant-based antibacterial sanitary napkin surface material.

[0017] As an optimization, the preparation method of the pretreated bamboo pulp fiber in step (1) is: mixing bamboo pulp fiber and 2wt% 3-chloropropyltriethoxysilane-ethanol solution in a mass ratio of 1:30, stirring at 25°C for 1h, filtering and washing with pure water, and vacuum drying at 60°C to obtain pretreated bamboo pulp fiber; the bamboo pulp fiber is wormwood-modified bamboo pulp fiber, with a specification of 1.33dtex×38mm.

[0018] As an optimization, the sodium hypobromite solution in step (2) is obtained by mixing bromine and 4 mol / L sodium hydroxide in a volume ratio of 1:15.

[0019] As an optimization, the hemp fiber in step (3) is fully degummed hemp fiber.

[0020] As an optimization, the preparation method of the imidazole quaternary ammonium salt in step (5) is as follows: methyl (2-methyl-1H-benzimidazole-1-yl) acetate and iodomethane are weighed in a molar ratio of 1:1, methyl (2-methyl-1H-benzimidazole-1-yl) acetate, iodomethane, and acetonitrile with a mass of 15 times that of iodomethane are mixed, and refluxed at 85°C for 32 hours. After the reaction is completed, the imidazole quaternary ammonium salt precursor is obtained by vacuum distillation and recrystallization from acetone; the imidazole quaternary ammonium salt precursor, N,N-dimethylformamide, and 1M sodium hydroxide solution ammonia mass ratio of 1:40:40 are mixed, and refluxed at 110°C for 48 hours. After the reaction is completed, pure water is added, and the pH is adjusted to 1 with hydrochloric acid. After filtering and drying, the mixture is recrystallized with ethanol to obtain the imidazole quaternary ammonium salt.

[0021] As an optimization, the preparation method of the formaldehyded sodium alginate in step (5) is as follows: sodium alginate, pure water, and 10 wt% sodium periodate solution are mixed in a mass ratio of 1:1000:10.8, stirred in the dark for 4 hours, and then ethylene glycol in an amount equal to that of the sodium alginate is added, and dialyzed with pure water for three days, and freeze-dried to obtain the formaldehyded sodium alginate.

[0022] The present invention also provides a sanitary napkin, the surface layer material of which is prepared by the method for preparing the natural plant-based antibacterial sanitary napkin surface layer material.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] When preparing the natural plant-based antibacterial sanitary napkin surface layer material, the present invention first reacts bamboo pulp fiber pretreated with 3-chloropropyltriethoxysilane with benzimidazole-1-acetic acid, and then undergoes amidation and sodium hypobromite degradation to obtain modified bamboo pulp fiber; secondly, hemp fiber is grafted with an initiator to initiate polymerization of acrylamide and N-isopropylacrylamide to obtain modified hemp fiber; finally, the modified bamboo pulp fiber and modified hemp fiber are subjected to cleaning, carding, web laying, hydroentanglement, degreasing, bleaching, and finishing with a finishing agent to obtain the natural plant-based antibacterial sanitary napkin surface layer material.

[0025] The fabric of the present invention innovatively adopts a mixed double-layer and double-material combination, with a two-layer structure, that is, the upper layer is made of hemp fiber and the lower layer is made of bamboo pulp fiber structure, which is formed in one step through a spunlace process. This allows consumers to come into contact with the natural hemp fiber layer when using it, achieving an antibacterial and safe experience, and quickly conducts liquid through the lower bamboo pulp fiber layer, reducing the feeling of stuffiness and increasing comfort.

[0026] First, bamboo pulp fibers were pretreated with 3-chloropropyltriethoxysilane to impart chlorine groups to the fibers. The chlorine groups then reacted with benzimidazole-1-acetic acid to form a quaternary ammonium salt with antibacterial properties. The quaternary ammonium salt was then amidated and degraded with sodium hypobromite to convert the carboxylic acid groups on the benzimidazole-1-acetic acid into amide groups, which were then degraded into amino groups.

[0027] Secondly, hemp fiber is grafted with an initiator to initiate the polymerization of acrylamide and N-isopropylacrylamide to obtain modified hemp fiber; hemp fiber has a cavity structure, and is connected to many cracks and small holes distributed longitudinally on the fiber surface. Its moisture-wicking ability is three times that of pure cotton. Hemp contains trace amounts of hemp phenols and more than ten trace elements that are beneficial to human health. Fibers containing polyacrylamide on the surface can enhance hydrophilicity;

[0028] Finally, the modified bamboo pulp fiber and modified hemp fiber are subjected to cleaning, carding, web laying, hydroentanglement, degreasing, bleaching, and finishing with a finishing agent to obtain a natural plant-based antibacterial sanitary napkin surface material; the finishing agent is a mixture of formaldehyde-modified sodium alginate and imidazole quaternary ammonium salt, and the formaldehyde-modified sodium alginate mainly modifies the bamboo pulp fiber surface of the surface layer by Schiff base reaction with the amino groups on the surface of the modified bamboo pulp fiber. The imidazole quaternary ammonium salt contains both positively charged amino groups and positively charged carboxyl groups, and the quaternary ammonium salt structure on the surface of the bamboo pulp fiber of the surface layer also contains both positively charged amino groups and positively charged carboxyl groups, which can form a hydrogel film on the surface layer through self-assembly through the attraction between positive and negative charges. The hydrogel film has good water absorption and swelling properties, which can improve the water absorption of the material, and the quaternary ammonium salt structure can further improve the antibacterial performance; menstrual blood contains a small amount of calcium ions, and sodium alginate and polyacrylamide on the surface of hemp fiber can be cross-linked by calcium ions to form a network, which can not only improve the water absorption of the material, but also prevent the reverse osmosis of menstrual blood. DETAILED DESCRIPTION

[0029] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0030] The bamboo pulp fiber used in the following examples and comparative examples is mugwort-modified bamboo pulp fiber with a specification of 1.33 dtex × 38 mm; the hemp fiber used is fully degummed hemp fiber; the sodium hypobromite solution used is obtained by mixing bromine and 4 mol / L sodium hydroxide in a volume ratio of 1:15.

[0031] Example 1:

[0032] A method for preparing a natural plant-based antibacterial sanitary napkin surface material, the method comprising the following steps:

[0033] (1) Bamboo pulp fiber and 2 wt% 3-chloropropyltriethoxysilane-ethanol solution were mixed in a mass ratio of 1:30, stirred at 25°C for 1 hour, filtered and washed with pure water, and vacuum dried at 60°C to obtain pretreated bamboo pulp fiber; pretreated bamboo pulp fiber, benzimidazole-1-acetic acid, potassium iodide, and acetonitrile were mixed in a mass ratio of 1:0.5:0.2:20, heated to 95°C, reacted for 8 hours, filtered and washed with pure water 4 times, and vacuum dried at 60°C to obtain pre-modified bamboo pulp fiber;

[0034] (2) Pre-modified bamboo pulp fiber, dichlorothionyl, and N,N-dimethylformamide were mixed in a mass ratio of 1:10:0.1, heated to 80°C and refluxed for 40 minutes, filtered after the reaction, and dichloromethane 10 times the mass of the pre-modified bamboo pulp fiber and 25wt% ammonia water saturated with ammonium carbonate 2 times the mass of the pre-modified bamboo pulp fiber were added, reacted at room temperature for 30 minutes, filtered and washed with pure water 3 times, and vacuum dried at 60°C to obtain amidated bamboo pulp fiber; at 0°C, amidated bamboo pulp fiber, sodium hypobromite solution, and 4mol / L sodium hydroxide solution were mixed in a mass ratio of 1:5:0.6 and ultrasonicated for 10 minutes, then heated to 80°C, reacted for 1 hour, filtered and washed with pure water 3 times, and vacuum dried at 60°C to obtain modified bamboo pulp fiber;

[0035] (3) Weigh bromoisobutyryl bromide and pyridine in a molar ratio of 1:1, mix bromoisobutyryl bromide, pyridine, and dichloromethane 10 times the mass of pyridine, add hemp fiber 2 times the mass of pyridine, react at room temperature for 4 hours, filter and wash 4 times with ethanol to obtain pretreated hemp fiber; mix pretreated hemp fiber, N,N-dimethylformamide, cuprous bromide, pentamethyldiethylenetriamine, acrylamide, and N-isopropylacrylamide in a mass ratio of 1:20:0.1:0.01:0.2:0.2, react at 60°C for 4 hours, filter and wash 4 times with ethanol, and vacuum dry at 60°C to obtain modified hemp fiber;

[0036] (4) The modified bamboo pulp fiber and the modified hemp fiber were opened and combed respectively, and the modified bamboo pulp fiber and the modified hemp fiber were laid on a net at a mass ratio of 1:0.8, so that the modified bamboo pulp fiber was on the lower layer and the modified hemp fiber was on the upper layer, with a surface density of 40 g / m 2 , the fabric is subjected to hydroentanglement reinforcement treatment in a hydroentanglement machine with a hydroentanglement pressure of 50 MPa, a screen conveying speed of 4 m / min, a water needle distance of 14 mm, and a water spray hole diameter of 0.2 mm, and then degreased and bleached to obtain the grey fabric;

[0037] (5) Methyl (2-methyl-1H-benzimidazol-1-yl) acetate and iodomethane were weighed in a molar ratio of 1:1, and methyl (2-methyl-1H-benzimidazol-1-yl) acetate, iodomethane, and acetonitrile (15 times the mass of iodomethane) were mixed, and refluxed at 85°C for 32 hours. After the reaction, the mixture was subjected to reduced pressure distillation and recrystallized from acetone to obtain an imidazole quaternary ammonium salt precursor; an imidazole quaternary ammonium salt precursor, N,N-dimethylformamide, and 1M sodium hydroxide solution (ammonia) were mixed in a mass ratio of 1:40:40, and refluxed at 110°C for 48 hours. After the reaction, pure water was added, and the pH was adjusted to 1 with hydrochloric acid. After filtration and drying, the mixture was recrystallized from ethanol to obtain an imidazole quaternary ammonium salt; Sodium alginate, pure water, and 10wt% sodium periodate solution are mixed in a mass ratio of 1:1000:10.8, stirred in the dark for 4 hours, and then ethylene glycol of the same mass as the sodium alginate is added, and the mixture is dialyzed with pure water for three days, and freeze-dried to obtain formaldehyded sodium alginate; at 80°C, formaldehyded sodium alginate, benzimidazole quaternary ammonium salt, and pure water are mixed in a mass ratio of 1:2:20 to obtain a finishing agent solution, and the solution is added to the grey cloth, wherein the mass ratio of the grey cloth to the finishing solution is 1:20, and after immersion for 30 minutes, the solution is immersed and rolled, the immersion and rolling temperature is 70°C, the rolling rate is 120%, the solution is pre-dried at 70°C for 3 minutes, and dried at room temperature to obtain a natural plant-based antibacterial sanitary napkin surface material.

[0038] Example 2:

[0039] A method for preparing a natural plant-based antibacterial sanitary napkin surface material, the method comprising the following steps:

[0040] (1) Bamboo pulp fiber and 2 wt% 3-chloropropyltriethoxysilane-ethanol solution were mixed in a mass ratio of 1:30, stirred at 25°C for 1 hour, filtered and washed with pure water, and vacuum dried at 60°C to obtain pretreated bamboo pulp fiber; pretreated bamboo pulp fiber, benzimidazole-1-acetic acid, potassium iodide, and acetonitrile were mixed in a mass ratio of 1:0.6:0.25:25, heated to 93°C, reacted for 7 hours, filtered, washed with pure water three times, and vacuum dried at 60°C to obtain pre-modified bamboo pulp fiber;

[0041] (2) Pre-modified bamboo pulp fiber, dichlorothionyl, and N,N-dimethylformamide were mixed in a mass ratio of 1:11:0.15, heated to 76°C and refluxed for 35 minutes, filtered after the reaction, and 11 times the mass of the pre-modified bamboo pulp fiber and 25 wt% ammonia saturated with ammonium carbonate were added. The mixture was reacted at room temperature for 25 minutes, filtered, washed with pure water three times, and vacuum dried at 60°C to obtain amidated bamboo pulp fiber; at -4°C, amidated bamboo pulp fiber, sodium hypobromite solution, and 4 mol / L sodium hydroxide solution were mixed in a mass ratio of 1:6:0.65 and ultrasonicated for 10 minutes, then heated to 76°C, reacted for 1 hour, filtered, washed with pure water three times, and vacuum dried at 60°C to obtain modified bamboo pulp fiber;

[0042] (3) Weigh bromoisobutyryl bromide and pyridine in a molar ratio of 1:1, mix bromoisobutyryl bromide, pyridine, and dichloromethane 11 times the mass of pyridine, add hemp fiber 2.5 times the mass of pyridine, react at room temperature for 4 hours, filter and wash with ethanol 4 times to obtain pretreated hemp fiber; mix pretreated hemp fiber, N,N-dimethylformamide, cuprous bromide, pentamethyldiethylenetriamine, acrylamide, and N-isopropylacrylamide in a mass ratio of 1:25:0.15:0.015:0.25:0.26, react at 60°C for 4 hours, filter and wash with ethanol 4 times, and vacuum dry at 60°C to obtain modified hemp fiber;

[0043] (4) The modified bamboo pulp fiber and the modified hemp fiber were opened and combed respectively, and the modified bamboo pulp fiber and the modified hemp fiber were laid on a net at a mass ratio of 1:1, so that the modified bamboo pulp fiber was on the lower layer and the modified hemp fiber was on the upper layer, with a surface density of 50 g / m 2 , the fabric is subjected to hydroentanglement reinforcement treatment in a hydroentanglement machine with a hydroentanglement pressure of 45 MPa, a screen conveying speed of 4 m / min, a water needle distance of 14 mm, and a water spray hole diameter of 0.2 mm, and then degreased and bleached to obtain the grey fabric;

[0044] (5) Methyl (2-methyl-1H-benzimidazol-1-yl) acetate and iodomethane were weighed in a molar ratio of 1:1, methyl (2-methyl-1H-benzimidazol-1-yl) acetate, iodomethane and acetonitrile (15 times the mass of iodomethane) were mixed, and refluxed at 85°C for 32 hours. After the reaction, the mixture was distilled under reduced pressure and recrystallized from acetone to obtain an imidazole quaternary ammonium salt precursor; imidazole quaternary ammonium salt precursor, N,N-dimethylformamide and 1M sodium hydroxide solution (ammonia) were mixed in a mass ratio of 1:40:40, and refluxed at 110°C for 48 hours. After the reaction, pure water was added, and the pH was adjusted to 1 with hydrochloric acid. After filtration and drying, the mixture was recrystallized from ethanol to obtain an imidazole quaternary ammonium salt; Sodium alginate, pure water, and 10wt% sodium periodate solution are mixed in a mass ratio of 1:1000:10.8, stirred in the dark for 4 hours, and then ethylene glycol in an amount equal to that of the sodium alginate is added, and the mixture is dialyzed with pure water for three days, and freeze-dried to obtain formaldehyded sodium alginate; at 75°C, formaldehyded sodium alginate, benzimidazole quaternary ammonium salt, and pure water are mixed in a mass ratio of 1:2.5:25 to obtain a finishing agent solution, which is added to grey fabric, wherein the mass ratio of the grey fabric to the finishing solution is 1:25, and the mixture is immersed for 25 minutes, followed by dipping and rolling, the dipping and rolling temperature is 65°C, the rolling rate is 110%, pre-baking is performed at 65°C for 2.5 minutes, and drying is performed at room temperature to obtain a natural plant-based antibacterial sanitary napkin surface layer material.

[0045] Example 3:

[0046] A method for preparing a natural plant-based antibacterial sanitary napkin surface material, the method comprising the following steps:

[0047] (1) Bamboo pulp fiber and 2 wt% 3-chloropropyltriethoxysilane-ethanol solution were mixed in a mass ratio of 1:30, stirred at 25°C for 1 hour, filtered and washed with pure water, and vacuum dried at 60°C to obtain pretreated bamboo pulp fiber; pretreated bamboo pulp fiber, benzimidazole-1-acetic acid, potassium iodide, and acetonitrile were mixed in a mass ratio of 1:0.7:0.3:30, heated to 90°C, reacted for 6 hours, filtered and washed with pure water three times, and vacuum dried at 60°C to obtain pre-modified bamboo pulp fiber;

[0048] (2) Pre-modified bamboo pulp fiber, thionyl chloride, and N,N-dimethylformamide were mixed in a mass ratio of 1:12:0.2, heated to 75°C and refluxed for 30 minutes, filtered after the reaction, and dichloromethane 12 times the mass of the pre-modified bamboo pulp fiber and 25wt% ammonia saturated with ammonium carbonate 3 times the mass of the pre-modified bamboo pulp fiber were added, reacted at room temperature for 20 minutes, filtered and washed with pure water 3 times, and vacuum dried at 60°C to obtain amidated bamboo pulp fiber; at -5°C, amidated bamboo pulp fiber, sodium hypobromite solution, and 4mol / L sodium hydroxide solution were mixed in a mass ratio of 1:7:0.7 and ultrasonicated for 10 minutes, then heated to 75°C, reacted for 1 hour, filtered and washed with pure water 3 times, and vacuum dried at 60°C to obtain modified bamboo pulp fiber;

[0049] (3) Weigh bromoisobutyryl bromide and pyridine in a molar ratio of 1:1, mix bromoisobutyryl bromide, pyridine, and dichloromethane 12 times the mass of pyridine, add hemp fiber 3 times the mass of pyridine, react at room temperature for 4 hours, filter and wash 4 times with ethanol to obtain pretreated hemp fiber; mix pretreated hemp fiber, N,N-dimethylformamide, cuprous bromide, pentamethyldiethylenetriamine, acrylamide, and N-isopropylacrylamide in a mass ratio of 1:30:0.2:0.02:0.3:0.3, react at 60°C for 4 hours, filter and wash 4 times with ethanol, and vacuum dry at 60°C to obtain modified hemp fiber;

[0050] (4) The modified bamboo pulp fiber and the modified hemp fiber were opened and combed respectively, and the modified bamboo pulp fiber and the modified hemp fiber were laid on a net at a mass ratio of 1:1.2, so that the modified bamboo pulp fiber was on the lower layer and the modified hemp fiber was on the upper layer, with a surface density of 60 g / m 2 , the fabric is subjected to hydroentanglement reinforcement treatment in a hydroentanglement machine with a hydroentanglement pressure of 40 MPa, a screen conveying speed of 4 m / min, a water needle distance of 14 mm, and a water spray hole diameter of 0.2 mm, and then degreased and bleached to obtain the grey fabric;

[0051] (5) Methyl (2-methyl-1H-benzimidazol-1-yl) acetate and iodomethane were weighed in a molar ratio of 1:1, and methyl (2-methyl-1H-benzimidazol-1-yl) acetate, iodomethane, and acetonitrile (15 times the mass of iodomethane) were mixed, and refluxed at 85°C for 32 hours. After the reaction, the mixture was subjected to reduced pressure distillation and recrystallized from acetone to obtain an imidazole quaternary ammonium salt precursor; an imidazole quaternary ammonium salt precursor, N,N-dimethylformamide, and 1M sodium hydroxide solution (ammonia) were mixed in a mass ratio of 1:40:40, and refluxed at 110°C for 48 hours. After the reaction, pure water was added, and the pH was adjusted to 1 with hydrochloric acid. After filtration and drying, the mixture was recrystallized from ethanol to obtain an imidazole quaternary ammonium salt; Sodium alginate, pure water, and 10wt% sodium periodate solution are mixed in a mass ratio of 1:1000:10.8, stirred in the dark for 4 hours, and then ethylene glycol of the same mass as the sodium alginate is added, and the mixture is dialyzed with pure water for three days, and freeze-dried to obtain formaldehyded sodium alginate; at 70°C, formaldehyded sodium alginate, benzimidazole quaternary ammonium salt, and pure water are mixed in a mass ratio of 1:3:30 to obtain a finishing agent solution, and the solution is added to the grey cloth, wherein the mass ratio of the grey cloth to the finishing solution is 1:30, and after immersion for 20 minutes, the solution is immersed and rolled, the immersion and rolling temperature is 60°C, the rolling rate is 100%, and the solution is pre-dried at 60°C for 2 minutes. The solution is dried at room temperature to obtain a natural plant-based antibacterial sanitary napkin surface material.

[0052] Comparative Example 1:

[0053] The preparation method of the natural plant-based antibacterial sanitary napkin surface material of Comparative Example 1 differs from that of Example 2 in that it does not contain steps (1) to (2) and (5), and step (4) is modified as follows: the bamboo pulp fiber and the modified hemp fiber are opened and combed, and the bamboo pulp fiber and the modified hemp fiber are laid out in a mass ratio of 1:1, so that the modified bamboo pulp fiber is in the lower layer and the modified hemp fiber is in the upper layer, and the surface density is 50 g / m 2 The hydroentanglement reinforcement treatment is carried out in a hydroentanglement machine. The hydroentanglement pressure of the hydroentanglement machine is 45MPa, the screen curtain speed is 4m / min, the water needle distance is 14mm, and the water spray hole diameter is 0.2mm. Then, the natural plant-based antibacterial sanitary napkin surface material is obtained by degreasing and bleaching.

[0054] Comparative Example 2:

[0055] The preparation method of the natural plant-based antibacterial sanitary napkin surface material of Comparative Example 2 differs from that of Example 2 in that step (3) is not included, and step (4) is modified as follows: the modified bamboo pulp fiber and the hemp fiber are loosened and combed, and the modified bamboo pulp fiber and the hemp fiber are laid on a net at a mass ratio of 1:1, so that the modified bamboo pulp fiber is in the lower layer and the modified hemp fiber is in the upper layer, with a surface density of 50 g / m 2The fabric is subjected to hydroentanglement reinforcement treatment in a hydroentanglement machine with a hydroentanglement pressure of 45 MPa, a screen conveying speed of 4 m / min, a water needle distance of 14 mm, and a water spray hole diameter of 0.2 mm. The fabric is then degreased and bleached to obtain the grey fabric.

[0056] Test Example 1:

[0057] Absorption performance test:

[0058] Test Method: The back permeation of the Examples and Comparative Examples was tested according to the GB / T30133-2013 standard. The test solution used in the experiments was replaced with anticoagulated pig blood. The Examples and Comparative Examples were cut into 100 mm x 100 mm specimens. Each specimen was tested five times, and the average value was taken. The results are shown in Table 1.

[0059] Table 1

[0060] Re-seepage amount (g) Re-seepage amount (g) Example 1 0.5763 Comparative Example 1 1.4863 Example 2 0.5642 Comparative Example 2 1.0633 Example 3 0.5621

[0061] From the comparison of the experimental data of Examples 1 to 3 and Comparative Examples 1 to 2 in Table 1, it can be found that the antibacterial sanitary napkin surface layer material prepared by the present invention has good anti-rewetting performance.

[0062] By comparison, the back-seepage amount of Examples 1 to 3 is less than that of Comparative Examples 1 to 2, indicating that the modified bamboo pulp fiber and the modified hemp fiber are subjected to cleaning, carding, web laying, hydroentanglement, degreasing, bleaching, and finishing with a finishing agent to obtain a natural plant-based antibacterial sanitary napkin surface material; the finishing agent is a mixture of formaldehyde-modified sodium alginate and imidazole quaternary ammonium salt, the formaldehyde-modified sodium alginate reacts with the amino groups on the surface of the modified bamboo pulp fiber to mainly modify the surface of the bamboo pulp fiber, and the imidazole quaternary ammonium salt contains both positively charged amino groups and The positively charged carboxyl group and the quaternary ammonium salt structure on the surface of the bamboo pulp fiber also contain positively charged amino groups and positively charged carboxyl groups. They can form a hydrogel film on the surface through self-assembly through the attraction between positive and negative charges. The hydrogel film has good water absorption and swelling properties, which can improve the water absorption of the material; menstrual blood contains a small amount of calcium ions, and sodium alginate and polyacrylamide on the surface of hemp fiber can be cross-linked through calcium ions to form a network, which can not only improve the water absorption of the material, but also prevent the reverse osmosis of menstrual blood.

[0063] Test Example 2:

[0064] Antibacterial performance test:

[0065] Test method: The antibacterial properties of the sanitary napkin fabrics prepared in the examples and comparative examples were tested according to the GB / T20944.2 standard. The results are shown in Table 2.

[0066] Table 2

[0067] Antibacterial rate (%) Antibacterial rate (%) Example 1 99.74 Comparative Example 1 92.31 Example 2 99.81 Comparative Example 2 99.63 Example 3 99.89

[0068] From the comparison of the experimental data of Examples 1 to 3 and Comparative Examples 1 to 2 in Table 2, it can be found that the antibacterial sanitary napkin surface layer material prepared by the present invention has good antibacterial properties.

[0069] By comparison, the antibacterial rates of Examples 1 to 3 are greater than that of Comparative Example 1, indicating that the bamboo pulp fibers pretreated with 3-chloropropyltriethoxysilane carry chlorine groups on the bamboo pulp fibers, and the chlorine groups react with benzimidazole-1-acetic acid to generate quaternary ammonium salts with antibacterial properties. The modified bamboo pulp fibers and modified hemp fibers are subjected to cleaning, carding, web laying, hydroentanglement, degreasing, bleaching, and finishing with a finishing agent to obtain a natural plant-based antibacterial sanitary napkin surface material; the finishing agent is a mixture of formaldehyde-modified sodium alginate and imidazole quaternary ammonium salt, and the formaldehyde-modified sodium alginate is obtained. By reacting the amino groups on the surface of the modified bamboo pulp fiber with a Schiff base, the surface of the bamboo pulp fiber is mainly modified. The imidazole quaternary ammonium salt contains both positively charged amino groups and positively charged carboxyl groups. The quaternary ammonium salt structure on the surface of the bamboo pulp fiber also contains both positively charged amino groups and positively charged carboxyl groups. It can form a hydrogel film on the surface through self-assembly through the attraction between positive and negative charges. The hydrogel film has good water absorption and swelling properties, which can improve the water absorption of the material. The quaternary ammonium salt structure can further improve the antibacterial properties.

[0070] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims, not the foregoing description, and all variations within the meaning and range of equivalents of the claims are intended to be encompassed therein. Any reference in a claim should not be construed as limiting the claim to which it relates.

Claims

1. A method for preparing a natural plant-based antibacterial sanitary napkin surface material, characterized in that: The preparation method comprises the following steps: (1) Pretreated bamboo pulp fiber, benzimidazole-1-acetic acid, potassium iodide, and acetonitrile were mixed in a mass ratio of 1:(0.5-0.7):(0.2-0.3):(20-30), heated to 90-95°C, reacted for 6-8h, filtered, washed with pure water 3-4 times, and vacuum dried at 60°C to obtain pre-modified bamboo pulp fiber; (2) Pre-modified bamboo pulp fiber, thionyl chloride, and N,N-dimethylformamide were mixed in a mass ratio of 1:(10-12):(0.1-0.2), heated to 75-80°C and refluxed for 30-40 minutes. After the reaction, the mixture was filtered and 10-12 times the mass of pre-modified bamboo pulp fiber and 25wt% ammonia saturated with ammonium carbonate were added. The mixture was reacted at room temperature for 20-30 minutes, filtered, and washed with pure water for 3-4 times. The method comprises the following steps: vacuum drying at 0°C to obtain amidated bamboo pulp fiber; mixing bromine and 4 mol / L sodium hydroxide in a volume ratio of 1:15 to obtain a sodium hypobromite solution; mixing the amidated bamboo pulp fiber, the sodium hypobromite solution, and the 4 mol / L sodium hydroxide solution in a mass ratio of 1:(5-7):(0.6-0.7) at -5-0°C, ultrasonicating for 10 minutes, heating to 75-80°C, reacting for 1 hour, filtering, washing with pure water 3-4 times, and vacuum drying at 60°C to obtain modified bamboo pulp fiber; (3) Weigh bromoisobutyryl bromide and pyridine in a molar ratio of 1:1, mix bromoisobutyryl bromide, pyridine, and dichloromethane (10-12 times the mass of pyridine), add hemp fiber (2-3 times the mass of pyridine), react at room temperature for 4 hours, filter and wash 4 times with ethanol to obtain pretreated hemp fiber; mix pretreated hemp fiber, N,N-dimethylformamide, cuprous bromide, pentamethyldiethylenetriamine, acrylamide, and N-isopropylacrylamide in a mass ratio of 1:(20-30):(0.1-0.2):(0.01-0.02):(0.2-0.3):(0.2-0.3), react at 60°C for 4 hours, filter and wash 4 times with ethanol, and vacuum dry at 60°C to obtain modified hemp fiber; (4) The modified bamboo pulp fiber and the modified hemp fiber are loosened and combed respectively, and the modified bamboo pulp fiber and the modified hemp fiber are laid on a net at a mass ratio of 1: (0.8-1.2), so that the modified bamboo pulp fiber is on the lower layer and the modified hemp fiber is on the upper layer, with a surface density of 40-60g / m 2 , the fabric is subjected to hydroentanglement reinforcement treatment in a hydroentanglement machine, the hydroentanglement pressure of the hydroentanglement machine is 40-50MPa, the screen conveying speed is 4m / min, the water needle distance is 14mm, the water spray hole diameter is 0.2mm, and then the fabric is degreased and bleached to obtain the grey fabric; (5) At 70-80°C, formaldehyde-modified sodium alginate, benzimidazole quaternary ammonium salt, and pure water are mixed in a mass ratio of 1:(2-3):(20-30) to obtain a finishing agent solution, which is added to the grey fabric, wherein the mass ratio of the grey fabric to the finishing solution is 1:(20-30). After immersion for 20-30 minutes, the mixture is immersed and rolled at a immersion and rolling temperature of 60-70°C and a rolling rate of 100%-120%. The mixture is pre-dried at 60-70°C for 2-3 minutes and dried at room temperature to obtain a natural plant-based antibacterial sanitary napkin surface material.

2. The method for preparing a natural plant-based antibacterial sanitary napkin surface material according to claim 1, characterized in that: The preparation method of the pretreated bamboo pulp fiber in step (1) is as follows: bamboo pulp fiber and 2wt% 3-chloropropyltriethoxysilane-ethanol solution are mixed in a mass ratio of 1:30, stirred at 25°C for 1h, filtered and washed with pure water, and vacuum dried at 60°C to obtain pretreated bamboo pulp fiber; the bamboo pulp fiber is wormwood-modified bamboo pulp fiber with a specification of 1.33dtex×38mm.

3. The method for preparing a natural plant-based antibacterial sanitary napkin surface material according to claim 1, characterized in that: The hemp fiber in step (3) is fully degummed hemp fiber.

4. The method for preparing a natural plant-based antibacterial sanitary napkin surface material according to claim 1, characterized in that: The preparation method of the benzimidazole quaternary ammonium salt in step (5) is as follows: methyl (2-methyl-1H-benzimidazole-1-yl) acetate and iodomethane are weighed in a molar ratio of 1:1, methyl (2-methyl-1H-benzimidazole-1-yl) acetate, iodomethane and acetonitrile with a mass of 15 times that of iodomethane are mixed, and the mixture is refluxed at 85°C for 32 hours. After the reaction is completed, the mixture is subjected to reduced pressure distillation and recrystallization from acetone to obtain a benzimidazole quaternary ammonium salt precursor; the benzimidazole quaternary ammonium salt precursor, N,N-dimethylformamide and 1M sodium hydroxide solution are mixed in a mass ratio of 1:40:40, and the mixture is refluxed at 110°C for 48 hours. After the reaction is completed, pure water is added, and the pH is adjusted to 1 with 35wt% hydrochloric acid. After filtering and drying, the mixture is recrystallized with ethanol to obtain a benzimidazole quaternary ammonium salt.

5. The method for preparing a natural plant-based antibacterial sanitary napkin surface material according to claim 1, characterized in that: The preparation method of the aldehyde-modified sodium alginate in step (5) is as follows: sodium alginate, pure water, and 10 wt% sodium periodate solution are mixed in a mass ratio of 1:1000:10.8, stirred in the dark for 4 hours, and then ethylene glycol in an amount equal to that of the sodium alginate is added, and the mixture is dialyzed with pure water for three days, and freeze-dried to obtain the aldehyde-modified sodium alginate.

6. A sanitary napkin, characterized in that: The surface layer material of the sanitary napkin is a natural plant-based antibacterial sanitary napkin surface layer material prepared by the preparation method according to any one of claims 1 to 5.