Composite fiber paper and preparation method thereof

Abstract

The present invention provides composite fiber paper and a method for preparing the same. The method comprises: feeding polypropylene fibers into a fiber deflaker and adding water to deflake them to obtain polypropylene fiber slurry; feeding para-aramid fibers into the fiber deflaker containing the polypropylene fiber slurry and continuing to add water to deflake them to obtain composite fiber slurry; feeding a dispersant, a surfactant, an inorganic filler, and the composite fiber slurry into a pulping tank, adding water to mix them, and preparing a pulp; and sequentially wet-sheeting the pulp, dehydrating it by pressing, drying it, and hot-pressing it to obtain composite fiber paper. The para-aramid fibers used in the present invention are plasma-pretreated para-aramid fibers. The present invention can produce durable composite fiber paper with excellent antibacterial properties.

Description

Technical Field

[0001] The present invention relates to the technical field of papermaking, and in particular to a composite fiber paper and a preparation method thereof. Background Art

[0002] Composite fiber paper containing polyolefin fiber components (polyethylene PE, polypropylene PP) has broad application prospects in many fields such as industry, life, and medical care.

[0003] Among these, polypropylene fiber, with its low price and excellent chemical stability, has attracted the attention of those skilled in the art for its application in papermaking. Blending polypropylene fiber with plant fibers in papermaking can improve paper quality and wet strength. By altering the elastic modulus of paper, it imparts a certain degree of elasticity and enhances its durability.

[0004] Furthermore, para-aramid fiber (poly(p-phenylene terephthalamide)) is a prime example of high-performance synthetic fibers due to its high specific strength, high specific modulus, low relative density, and excellent dimensional stability. Papermaking technologies utilizing para-aramid chopped fibers, para-aramid pulp fibers, and para-aramid fibrids have already emerged. With the development of the modern papermaking industry, para-aramid fiber has become an important raw material for papermaking.

[0005] Papermaking methods can be categorized into two main types: dry-laid and wet-laid. The main difference is that the wet-laid method uses water as the papermaking medium, while the dry-laid method uses air. Because the wet-laid method uses water as the papermaking medium, water must be added to create a uniform fiber suspension before papermaking begins, and the water is removed during the papermaking process.

[0006] Polypropylene-para-aramid fiber composite paper produced using a wet papermaking process exhibits excellent durability and chemical stability. However, due to the low surface energy of polypropylene, its dyeability is poor, which limits the further promotion and application of this type of composite fiber paper. To overcome these shortcomings, providing a polypropylene-para-aramid fiber composite paper with good dyeability is an urgent task in the field. In addition, further improving the heat resistance of polypropylene-para-aramid fiber composite paper is also of great significance. Summary of the Invention

[0007] One of the problems solved by the present invention is how to provide a polypropylene-para-aramid fiber composite fiber paper with good dyeability, and the second problem solved by the present invention is how to provide a polypropylene-para-aramid fiber composite fiber paper with excellent heat resistance.

[0008] To solve at least one of the above problems, the present invention provides a method for preparing composite fiber paper, the preparation method comprising:

[0009] S100, feeding the polypropylene fibers into a fiber deflaking machine and adding water to deflake the fibers at a mass ratio of polypropylene fibers to water of (0.4-0.8):100 to obtain a polypropylene fiber slurry;

[0010] S200, feeding the para-aramid fiber into a fiber deflaking machine containing the polypropylene fiber slurry obtained in S100 according to a mass ratio of polypropylene fiber: para-aramid fiber = (0.4-0.8): (1-1.2), and continuing to add water for deflaking to obtain a composite fiber slurry with a composite fiber mass concentration of 0.8% to 1.2%;

[0011] S300, according to the mass ratio of dispersant: surfactant: inorganic filler: composite fiber slurry = (0.4-0.6): (1-2): (4-8): 100, the dispersant, surfactant, inorganic filler and composite fiber slurry obtained in S200 are fed into a pulp preparation tank, water is added and mixed, and a pulp having a composite fiber mass concentration of 0.3%-0.6% is obtained;

[0012] S400, sequentially wet-papering, squeezing and dehydrating, drying, and hot-pressing the pulp obtained in S300 to obtain composite fiber paper;

[0013] The polypropylene fiber used in S100 is a polypropylene fiber pre-treated by plasma using ammonia as the working gas, and the inorganic filler used in S300 includes talc powder.

[0014] In any of the above technical solutions, in S100, the relief time is 20 minutes to 40 minutes; in S200, the relief time is 20 minutes to 40 minutes.

[0015] In any of the above technical solutions, in S400 , the process parameters of the squeezing dehydration are: positive pressure for 4 to 6 minutes, and reverse pressure for 4 to 6 minutes.

[0016] In any of the above technical solutions, in S400, the drying process parameters are: infrared drying at a temperature of 80°C to 90°C.

[0017] In any of the above technical solutions, in S400, the process parameters of the hot pressing molding are:

[0018] First, use a preheating press to perform preheating pressing at a temperature of 120°C to 140°C for 25s to 35s;

[0019] Then, a roller hot press is used to perform hot pressing for 6 to 8 minutes at a roller speed of 1.6 to 1.8 m / min, a temperature of 250 to 260° C., and a pressure of 14 to 16 MPa.

[0020] In any of the above technical solutions, the dispersant in S300 includes sodium hexametaphosphate, and the surfactant includes sodium dodecylbenzenesulfonate.

[0021] In any of the above technical solutions, the lengths of the polypropylene fibers and the para-aramid fibers are 2 mm to 6 mm, and the diameters are 1 μm to 4 μm, respectively.

[0022] In any of the above technical solutions, the polypropylene fiber used in S100 is prepared by the following steps:

[0023] S11, heating the polypropylene fiber in ethyl acetate to 55° C. to 60° C., soaking the fiber in the heat for 15 to 20 minutes, taking it out, washing it with water, and drying it;

[0024] S12. The polypropylene fiber obtained by S11 is sent into the chamber of a plasma reaction device. After the chamber is evacuated to below 20 Pa, ammonia gas is introduced into the chamber until the pressure in the chamber reaches 80 Pa to 100 Pa. The power supply of the ion reaction device is started, and the polypropylene fiber in the chamber is subjected to plasma pretreatment at a power of 80 W to 120 W for 8 minutes to 10 minutes.

[0025] In any of the above technical solutions, the inorganic filler used in S300 is prepared by the following steps:

[0026] S21, mixing talc and hydrochloric acid in water to obtain a first mixture;

[0027] S22, mixing dimethyldiethoxysilane, Tween 60, titanium tetrachloride, and paraffin in water and heating and stirring until emulsified to obtain a second mixture;

[0028] S23, gradually adding the second mixture dropwise to the first mixture while stirring, and uniformly emulsifying by ultrasonication after the addition is complete to obtain a third mixture;

[0029] S24. Add an alkaline solution dropwise to the third mixture while stirring until the pH value of the third mixture reaches 12 to 13. After standing and aging for 4 to 6 hours, filter, wash and calcine the solid matter in the third mixture to obtain an inorganic filler.

[0030] The present invention also provides a composite fiber paper, which is obtained by using the preparation method of any of the above technical solutions.

[0031] Beneficial effects

[0032] The preparation method of the present invention first feeds polypropylene fibers into a fiber deflaking machine and adds water to deflake them, obtaining a polypropylene fiber slurry. Para-aramid fibers are then fed into the fiber deflaking machine containing the polypropylene fiber slurry and further deflaked with water to obtain a composite fiber slurry with a composite fiber mass concentration of 0.8% to 1.2%. A dispersant, a surfactant, an inorganic filler, and the composite fiber slurry are then fed into a pulping tank, mixed with water, and mixed until a composite fiber mass concentration of 0.3% to 0.6% is obtained. Finally, the pulp is sequentially wet-laid, dehydrated by pressing, dried, and hot-pressed to obtain composite fiber paper. The polypropylene fibers used in the present invention are plasma-pretreated. The plasma pretreatment process activates the polypropylene fiber surface and increases its surface energy by removing surface defects. Ammonia, used as a working gas, also increases the number of amino functional groups on the polypropylene fiber surface, improving its hydrophilicity and, consequently, its dyeing properties and color fastness. Furthermore, the inorganic filler used in the present invention includes talc, which can improve the heat resistance of the composite fiber paper. DETAILED DESCRIPTION

[0033] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the following is a detailed description of the specific embodiments of the present invention.

[0034] Unless otherwise specified, the reagents and raw materials used in the present invention can be purchased from commercial sources. Experimental methods in the following examples where specific conditions are not specified were performed according to conventional methods and conditions, or selected according to the product specifications.

[0035] An embodiment of the present invention provides a method for preparing composite fiber paper, the method comprising:

[0036] S100, feeding the polypropylene fibers into a fiber deflaking machine and adding water to deflake the fibers at a mass ratio of polypropylene fibers to water of (0.4-0.8):100 to obtain a polypropylene fiber slurry;

[0037] S200, feeding the para-aramid fiber into a fiber deflaking machine containing the polypropylene fiber slurry obtained in S100 according to a mass ratio of polypropylene fiber: para-aramid fiber = (0.4-0.8): (1-1.2), and continuing to add water for deflaking to obtain a composite fiber slurry with a composite fiber mass concentration of 0.8% to 1.2%;

[0038] S300, according to the mass ratio of dispersant: surfactant: inorganic filler: composite fiber slurry = (0.4-0.6): (1-2): (4-8): 100, the dispersant, surfactant, inorganic filler and composite fiber slurry obtained in S200 are fed into a pulp preparation tank, water is added and mixed, and a pulp having a composite fiber mass concentration of 0.3%-0.6% is obtained;

[0039] S400, the paper pulp obtained in S300 is sequentially subjected to wet papermaking, pressing and dehydration, drying, and hot pressing to obtain composite fiber paper.

[0040] The purpose of the above steps is to prepare a polypropylene-para-aramid fiber composite fiber paper. Polypropylene fiber is a synthetic fiber spun from isotactic polypropylene obtained by polymerization of propylene, also known as polypropylene. Polypropylene fiber can be divided into long fibers and short fibers for textile use, and can also be made into non-woven fabrics. One of the advantages of polypropylene fiber is its light specific gravity, which is about 1 / 3 lighter than other synthetic fibers and natural fibers, making it relatively light to use. In addition, polypropylene fiber has strong corrosion resistance and is not easily affected by acid and alkali corrosive substances. The production process of polypropylene fiber is a relatively mature existing technology, and its preparation process mainly includes the steps of raw material preparation, melting and mixing, spinning, drawing and cooling, winding and cutting. The polypropylene fiber used in the present invention can be obtained directly through commercial procurement, so the production process of polypropylene fiber will not be described in detail in the present invention. Para-aramid fiber is a type of aramid fiber, which is an aramid fiber with two benzene rings connected by amide bonds in a para-position structure. Currently, there are two main types of aramid fibers on the market: meta-aramid and para-aramid. Para-aramid is widely used because of its extremely high strength and modulus, as well as excellent chemical corrosion resistance.

[0041] The composite fiber paper provided by the present invention is composed of a polymer. Furthermore, those skilled in the art may, as needed, add natural substances such as cellulose (e.g., lignin, sodium alginate, etc.) to the composite fiber paper provided by the present invention during the deflaking process. Alternatively, raw materials for binders, thickeners, and defoamers may be added during the pulping process.

[0042] In the present invention, the polypropylene fiber used in S100 is plasma pretreated using ammonia as the working gas, and the inorganic filler used in S300 includes talc. The plasma pretreatment process activates the polypropylene fiber surface, increasing its surface energy through surface defects. The use of ammonia as the working gas also increases the number of amino functional groups on the polypropylene fiber surface, improving its hydrophilicity and, consequently, its dyeing properties and color fastness. Furthermore, the inorganic filler used in the present invention includes talc, which can improve the heat resistance of the composite fiber paper.

[0043] In some embodiments of the present invention, in S100, the decongestion time is 20 minutes to 40 minutes; in S200, the decongestion time is 20 minutes to 40 minutes.

[0044] In a further preferred embodiment of the present invention, in S100, the decongestion time is 20 min to 30 min; in S200, the decongestion time is 20 min to 30 min.

[0045] In some embodiments of the present invention, in S400 , the process parameters of the squeezing dehydration are: positive pressure for 4 to 6 minutes, and reverse pressure for 4 to 6 minutes.

[0046] In a further preferred embodiment of the present invention, in S400 , the process parameters of the squeezing dehydration are: positive pressure for 4 to 5 minutes, and reverse pressure for 4 to 5 minutes.

[0047] In some embodiments of the present invention, in S400 , the drying process parameters are: infrared drying at a temperature of 80° C. to 90° C.

[0048] In a further preferred embodiment of the present invention, in S400, the drying process parameters are: infrared drying at a temperature of 80°C to 85°C.

[0049] In some embodiments of the present invention, in S400, the process parameters of the hot pressing molding are:

[0050] First, use a preheating press to perform preheating pressing at a temperature of 120°C to 140°C for 25s to 35s;

[0051] Then, a roller hot press is used to perform hot pressing for 6 to 8 minutes at a roller speed of 1.6 to 1.8 m / min, a temperature of 250 to 260° C., and a pressure of 14 to 16 MPa.

[0052] In a further preferred embodiment of the present invention, in S400, the process parameters of the hot pressing molding are:

[0053] First, use a preheating press to perform preheating pressing at a temperature of 125°C to 130°C for 25 seconds;

[0054] Then, a roller hot press was used to perform hot pressing for 6 minutes at a roller speed of 1.6 m / min, a temperature of 250° C., and a pressure of 14 MPa.

[0055] In some embodiments of the present invention, the dispersant in S300 includes sodium hexametaphosphate, and the surfactant includes sodium dodecylbenzenesulfonate.

[0056] In some embodiments of the present invention, the lengths of the polypropylene fibers and the para-aramid fibers are 2 mm to 6 mm, and the diameters are 1 μm to 4 μm, respectively.

[0057] In a further preferred embodiment of the present invention, the lengths of the polypropylene fibers and the para-aramid fibers are 2 mm to 4 mm, and the diameters are 2 μm to 3 μm, respectively.

[0058] In some embodiments of the present invention, the polypropylene fiber used in S100 is prepared by the following steps:

[0059] S11, heating the polypropylene fiber in ethyl acetate to 55° C. to 60° C., soaking the fiber in the heat for 15 to 20 minutes, taking it out, washing it with water, and drying it;

[0060] S12. The polypropylene fiber obtained by S11 is sent into the chamber of a plasma reaction device. After the chamber is evacuated to below 20 Pa, ammonia gas is introduced into the chamber until the pressure in the chamber reaches 80 Pa to 100 Pa. The power supply of the ion reaction device is started, and the polypropylene fiber in the chamber is subjected to plasma pretreatment at a power of 80 W to 120 W for 8 minutes to 10 minutes.

[0061] In S11, the ethyl acetate is preferably sufficient to immerse the polypropylene fiber. The heating temperature of the polypropylene fiber in the ethyl acetate is preferably 15° C. to 30° C. lower than the boiling point of the ethyl acetate. After the heat preservation and immersion, the polypropylene fiber needs to be washed with ethanol, then washed with water 2-3 times, and dried with hot air.

[0062] In S12, ammonia is used as the working gas for plasma pretreatment. The power of the plasma pretreatment is preferably 80W to 100W, and the time is preferably no more than 10 minutes.

[0063] In the above steps, the heating and soaking process in ethyl acetate removes impurities such as grease from the polypropylene fiber surface, while the plasma reaction activates the polypropylene fiber surface, increasing its surface energy by removing surface defects. Ammonia, as a working gas, also increases the number of amino functional groups on the polypropylene fiber surface, improving its hydrophilicity, thereby enhancing its dyeing properties and color fastness.

[0064] In some embodiments of the present invention, the inorganic filler used in S300 is prepared by the following steps:

[0065] S21, mixing talc and hydrochloric acid in water to obtain a first mixture;

[0066] S22, mixing dimethyldiethoxysilane, Tween 60, titanium tetrachloride, and paraffin in water and heating and stirring until emulsified to obtain a second mixture;

[0067] S23, gradually adding the second mixture dropwise to the first mixture while stirring, and uniformly emulsifying by ultrasonication after the addition is complete to obtain a third mixture;

[0068] S24. Add an alkaline solution dropwise to the third mixture while stirring until the pH value of the third mixture reaches 12 to 13. After standing and aging for 4 to 6 hours, filter, wash and calcine the solid matter in the third mixture to obtain an inorganic filler.

[0069] In a further preferred embodiment of the present invention, the inorganic filler used in S300 is prepared by the following steps:

[0070] S21. Mixing talc and hydrochloric acid in water at room temperature in a mass ratio of talc: hydrochloric acid: water = (18-22): (6-8): 100 to obtain a first mixture;

[0071] S22. Dimethyldiethoxysilane, Tween 60, titanium tetrachloride, and paraffin are mixed in water in a mass ratio of dimethyldiethoxysilane:Tween 60:titanium tetrachloride:paraffin:water = (0.5-1):(2-3):(6-11):(24-30):100, heated to 65° C. to 75° C., and stirred until emulsified to obtain a second mixture;

[0072] S23, gradually adding the second mixture dropwise to the first mixture at a mass ratio of the first mixture to the second mixture = 1:1.2 while stirring, and after the addition is complete, ultrasonically emulsifying the mixture to obtain a third mixture;

[0073] S24. Add 8wt% to 12wt% of an aqueous sodium hydroxide solution to the third mixture while stirring until the pH value of the third mixture reaches 12 to 13. After standing and aging for 4 to 6 hours, the solid matter in the third mixture is filtered, washed with water 2-3 times, and calcined at a temperature of 750°C to 800°C in an inert gas atmosphere for 1.5 to 2.5 hours to obtain an inorganic filler.

[0074] Talc can be used as a filler in plastic and paper products to improve their heat and high-temperature resistance. It also has excellent gloss and hiding power, enhancing the finish and texture of paper. Adding hydrochloric acid to talc to prepare a slurry can utilize the intercalation effect of hydrochloric acid to disrupt the interlayer structure of the talc, thereby improving its dispersibility and preventing aggregation, thereby producing a first mixture that serves as an aqueous suspension. Titanium tetrachloride is dissolved in water using dimethyldiethoxysilane as a coupling agent and Tween 60 as a catalyst, and paraffin is added to prepare a second mixture with an oil phase. By gradually adding the second mixture dropwise to the first mixture while stirring, microcapsules with an oil-in-water structure are obtained. The microcapsules have a talc core and an outer layer coated with a titanium-containing grease. Under alkaline conditions of a pH of 12 to 13, the titanium gradually precipitates on the surface of the talc core through static aging, forming a titanium hydroxide coating. This is then calcined to form a uniform titanium dioxide coating on the surface of the talc core. Titanium dioxide has a narrow band gap. Under sunlight, the electronic structure of titanium dioxide causes it to produce electron-hole pairs. These electron-hole pairs separate under the action of the electric field and migrate to different locations on the particle surface. Electrons can combine with oxygen dissolved on the surface of titanium dioxide to form superoxide ions, while holes will be adsorbed on the surface of titanium dioxide and oxidized into hydroxyl radicals. Hydroxyl radicals have strong oxidizing ability and can attack unsaturated bonds in organic matter or extract hydrogen atoms to produce new free radicals, stimulate chain reactions, and ultimately cause bacterial decomposition. Therefore, the titanium dioxide coating can give the inorganic filler an antibacterial and antifungal effect, thereby improving the antibacterial and mildew-proof properties of the polypropylene-para-aramid fiber composite fiber paper while ensuring its excellent heat resistance.

[0075] Example 1

[0076] This embodiment provides a method for preparing composite fiber paper, which specifically includes the following steps:

[0077] S1. Commercially purchased polypropylene fibers with a length of 2 mm to 4 mm and a diameter of 1 μm to 4 μm were heated to 55°C in ethyl acetate and soaked for 15 minutes. After removal, they were washed with ethanol, then washed with water 2-3 times, and dried with hot air.

[0078] S2. The polypropylene fibers obtained in S1 are fed into the chamber of a plasma reaction device. After the chamber is evacuated to below 20 Pa, ammonia gas is introduced into the chamber until the pressure in the chamber reaches 80 Pa. The power supply of the ion reaction device is turned on, and the polypropylene fibers in the chamber are subjected to plasma pretreatment at a power of 80 W for 8 minutes to obtain pretreated polypropylene fibers.

[0079] S3. The polypropylene fibers obtained in S2 were fed into a fiber deflaking machine and deflaked with water for 30 minutes at a mass ratio of polypropylene fiber to water of 0.5:100 to obtain a polypropylene fiber slurry.

[0080] S4. Commercially purchased para-aramid fibers with a length of 2 mm to 4 mm and a diameter of 1 μm to 4 μm are fed into a fiber deflaking machine containing the polypropylene fiber slurry obtained in S3 at a mass ratio of polypropylene fiber to para-aramid fiber of 0.5:1, and further deflaked by adding water to obtain a composite fiber slurry with a composite fiber mass concentration of 0.8%;

[0081] S5. Sodium hexametaphosphate, sodium dodecylbenzenesulfonate, talc, and the composite fiber slurry obtained in S4 are fed into a pulping tank in a mass ratio of sodium hexametaphosphate: sodium dodecylbenzenesulfonate: talc: composite fiber slurry = 0.4:1.2:5:100, and water is added to mix until a pulp having a composite fiber mass concentration of 0.5% is obtained;

[0082] S6, wet-papering the pulp obtained in S5 to obtain a wet paper web;

[0083] S7, pressing and dehydrating the wet paper obtained in S6 with positive pressure for 5 minutes and reverse pressure for 5 minutes;

[0084] S8, drying the dehydrated paper web obtained in S7 under infrared drying at a temperature of 80° C. to obtain a dry paper web;

[0085] S9. The dried paper web obtained in S8 is preheated and pressed at a temperature of 120° C. for 25 seconds using a preheating press; and then hot-pressed for 6 minutes using a roller hot press at a roller speed of 1.6 m / min, a temperature of 250° C., and a pressure of 14 MPa to obtain composite fiber paper.

[0086] Example 2

[0087] This embodiment provides a method for preparing composite fiber paper, which specifically includes the following steps:

[0088] S1. Commercially purchased polypropylene fibers with a length of 2 mm to 4 mm and a diameter of 1 μm to 4 μm were heated to 55° C. in ethyl acetate, kept warm and soaked for 15 minutes. After removal, they were washed with ethanol, then washed with water 2-3 times, and dried with hot air to obtain washed polypropylene fibers.

[0089] S2. The polypropylene fibers obtained in S1 were fed into a fiber deflaking machine and deflaked with water for 30 minutes at a mass ratio of polypropylene fiber to water of 0.5:100 to obtain a polypropylene fiber slurry.

[0090] S3. Commercially purchased para-aramid fibers with a length of 2 mm to 4 mm and a diameter of 1 μm to 4 μm are fed into a fiber deflaking machine containing the polypropylene fiber slurry obtained in S2 at a mass ratio of polypropylene fiber to para-aramid fiber of 0.5:1, and further deflaked by adding water to obtain a composite fiber slurry with a composite fiber mass concentration of 0.8%;

[0091] S4, according to the mass ratio of sodium hexametaphosphate: sodium dodecylbenzene sulfonate: composite fiber slurry = 0.4:1.2:100, sodium hexametaphosphate, sodium dodecylbenzene sulfonate and the composite fiber slurry obtained in S3 are fed into a pulp preparation tank, water is added and mixed, and a pulp having a composite fiber mass concentration of 0.5% is obtained;

[0092] S5, wet-papering the pulp obtained in S4 to obtain a wet paper web;

[0093] S6, pressing and dehydrating the wet paper obtained in S5 with positive pressure for 5 minutes and reverse pressure for 5 minutes;

[0094] S7, drying the dehydrated paper web obtained in S6 under infrared drying at a temperature of 80° C. to obtain a dry paper web;

[0095] S8. The dried paper web obtained in S7 is preheated and pressed at a temperature of 120° C. for 25 seconds using a preheating press; and then hot-pressed for 6 minutes using a roller hot press at a roller speed of 1.6 m / min, a temperature of 250° C., and a pressure of 14 MPa to obtain composite fiber paper.

[0096] Example 3

[0097] This embodiment provides a method for preparing composite fiber paper, and the preparation steps are the same as those in Example 1, except that the talc powder used in this embodiment is prepared by the following steps:

[0098] S1. Mixing talc and hydrochloric acid in water at room temperature in a mass ratio of talc: hydrochloric acid: water = 20:6:100 to obtain a first mixture;

[0099] S2. Dimethyldiethoxysilane, Tween 60, and paraffin are mixed in water in a mass ratio of dimethyldiethoxysilane: Tween 60: paraffin: water = 0.5:2:25:100, heated to 70° C., and rapidly stirred until emulsified to obtain a second mixture;

[0100] S3, gradually adding the second mixture dropwise to the first mixture at a mass ratio of the first mixture to the second mixture = 1:1.2 while stirring, and after the addition is complete, ultrasonically emulsifying the mixture to obtain a third mixture;

[0101] S4. Add 8 wt % aqueous sodium hydroxide solution to the third mixture while stirring until the pH value of the third mixture reaches 12. After standing and aging for 4 hours, the solid in the third mixture is filtered, washed with water 2-3 times, and calcined at 780° C. in a nitrogen inert gas atmosphere for 2 hours to obtain talc.

[0102] Example 4

[0103] This embodiment provides a method for preparing composite fiber paper, and the preparation steps are the same as those in Example 1, except that the talc powder used in this embodiment is prepared by the following steps:

[0104] S1. Mixing talc and hydrochloric acid in water at room temperature in a mass ratio of talc: hydrochloric acid: water = 20:6:100 to obtain a first mixture;

[0105] S2. Dimethyldiethoxysilane, Tween 60, titanium tetrachloride, and paraffin are mixed in water in a mass ratio of dimethyldiethoxysilane: Tween 60: titanium tetrachloride: paraffin: water = 0.5:2:8:25:100, heated to 70° C., and rapidly stirred until emulsified to obtain a second mixture;

[0106] S3, gradually adding the second mixture dropwise to the first mixture at a mass ratio of the first mixture to the second mixture = 1:1.2 while stirring, and after the addition is complete, ultrasonically emulsifying the mixture to obtain a third mixture;

[0107] S4. Add 8 wt % aqueous sodium hydroxide solution to the third mixture while stirring until the pH value of the third mixture reaches 12. After standing and aging for 4 hours, the solid in the third mixture is filtered, washed with water 2-3 times, and calcined at 780° C. in a nitrogen inert gas atmosphere for 2 hours to obtain talc.

[0108] Performance Testing

[0109] The mechanical properties of the paper prepared in Examples 1-4 of the present invention were tested, and the test results showed that:

[0110] (1) The tensile strengths of the composite fiber papers obtained in Examples 1-4 of the present invention are 265 MPa, 231 MPa, 268 MPa, and 279 MPa, respectively;

[0111] (2) Except for the composite fiber paper obtained in Example 2 of the present invention, which has a light fastness of level 3 after dyeing, the color fastness of the composite fiber paper obtained in the other examples of the present invention is greater than level 4;

[0112] (3) The antibacterial rates of Escherichia coli against the composite fiber papers obtained in Examples 1-4 of the present invention are 85%, 80%, 84% and 92% respectively.

[0113] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be based on the scope defined by the claims.

Claims

1. A method for preparing composite fiber paper, characterized in that: The preparation method comprises: S100, feeding the polypropylene fibers into a fiber deflaking machine and adding water to deflake the fibers at a mass ratio of polypropylene fibers to water of (0.4-0.8):100 to obtain a polypropylene fiber slurry; S200, feeding the para-aramid fiber into the fiber deflaking machine containing the polypropylene fiber slurry obtained in S100 according to a mass ratio of polypropylene fiber: para-aramid fiber = (0.4-0.8): (1-1.2), and continuing to add water for deflaking to obtain a composite fiber slurry with a composite fiber mass concentration of 0.8% to 1.2%; S300, according to the mass ratio of dispersant: surfactant: inorganic filler: composite fiber slurry = (0.4-0.6): (1-2): (4-8): 100, the dispersant, the surfactant, the inorganic filler and the composite fiber slurry obtained in S200 are fed into a pulp preparation tank, water is added and mixed, and a pulp having a composite fiber mass concentration of 0.3% to 0.6% is obtained; S400, sequentially subjecting the paper pulp obtained in S300 to wet papermaking, squeezing and dehydration, drying, and hot pressing to obtain the composite fiber paper; The polypropylene fiber used in S100 is a polypropylene fiber pre-treated by plasma using ammonia as a working gas, and the inorganic filler used in S300 includes talc powder.

2. The preparation method according to claim 1, characterized in that In S100, the relief time is 20 minutes to 40 minutes; in S200, the relief time is 20 minutes to 40 minutes.

3. The preparation method according to claim 1, characterized in that In S400 , the process parameters of the squeezing dehydration are: positive pressure for 4 to 6 minutes, and reverse pressure for 4 to 6 minutes.

4. The preparation method according to claim 1, characterized in that In S400, the drying process parameters are: infrared drying at a temperature of 80°C to 90°C.

5. The preparation method according to claim 1, characterized in that In S400, the process parameters of the hot pressing molding are: First, use a preheating press to perform preheating pressing at a temperature of 120°C to 140°C for 25s to 35s; Then, a roller hot press is used to perform hot pressing for 6 to 8 minutes at a roller speed of 1.6 to 1.8 m / min, a temperature of 250 to 260° C., and a pressure of 14 to 16 MPa.

6. The preparation method according to claim 1, characterized in that The dispersant in S300 includes sodium hexametaphosphate, and the surfactant includes sodium dodecylbenzenesulfonate.

7. The preparation method according to claim 1, characterized in that The lengths of the polypropylene fibers and the para-aramid fibers are 2 mm to 6 mm, and the diameters are 1 μm to 4 μm, respectively.

8. The preparation method according to any one of claims 1 to 7, characterized in that The polypropylene fiber used in S100 is prepared by the following steps: S11, heating the polypropylene fiber in ethyl acetate to 55° C. to 60° C., soaking the fiber in the heat for 15 to 20 minutes, taking it out, washing it with water, and drying it; S12. The polypropylene fiber obtained by S11 is sent into the chamber of a plasma reaction device. After evacuating the chamber to below 20 Pa, ammonia gas is introduced into the chamber until the pressure in the chamber reaches 80 Pa to 100 Pa. The power supply of the ion reaction device is started, and the polypropylene fiber in the chamber is subjected to plasma pretreatment at a power of 80 W to 120 W for 8 minutes to 10 minutes.

9. The preparation method according to any one of claims 1 to 7, characterized in that The inorganic filler used in S300 is prepared by the following steps: S21, mixing talc and hydrochloric acid in water to obtain a first mixture; S22, mixing dimethyldiethoxysilane, Tween 60, titanium tetrachloride, and paraffin in water and heating and stirring until emulsified to obtain a second mixture; S23, gradually adding the second mixture dropwise to the first mixture while stirring, and uniformly emulsifying through ultrasonication after the addition is complete to obtain a third mixture; S24. Add an alkaline solution dropwise to the third mixture while stirring until the pH value of the third mixture reaches 12 to 13. After standing and aging for 4 to 6 hours, filter, wash and calcine the solids in the third mixture to obtain the inorganic filler.

10. A composite fiber paper, characterized in that: The composite fiber paper is obtained by the preparation method according to any one of claims 1 to 9.