Polypropylene fiber cloth with hydrophilic and water-retention functions, and preparation method and application thereof

Abstract

The application relates to the technical field of new material preparation, and particularly discloses a polypropylene non-woven fabric with hydrophilic and water-retaining functions, a preparation method thereof and application. The polypropylene non-woven fabric comprises a polypropylene fiber fabric substrate and a hydrophilic polymer; the hydrophilic polymer is loaded on the surface of the polypropylene fiber fabric substrate and optionally loaded in the pores of the fibers, wherein the fiber diameter of the polypropylene fiber fabric after loading of the hydrophilic polymer is less than 25 microns. The polypropylene non-woven fabric has good hydrophilic and water-retaining properties, the static contact angle with water can reach 0-30 degrees, the water-retaining property is better, and the application field range of the polypropylene non-woven fabric is further widened. Moreover, the method for preparing the polypropylene non-woven fabric does not need any pretreatment such as graft modification of the polypropylene non-woven fabric, and the method has the characteristics of high efficiency, low consumption and low cost.

Description

Technical Field

[0001] This invention relates to the field of new material preparation technology, specifically to a polypropylene fiber cloth with hydrophilic and water-retaining functions, its preparation method, and its application. Background Technology

[0002] Polypropylene has a wide range of applications, including automobile manufacturing, electronics, building materials, and textiles. Polypropylene nonwoven fabric, as an important application of polypropylene materials, is a type of polypropylene fiber fabric. Current production processes for polypropylene nonwoven fabrics mainly involve meltblowing and spunbonding, with a small amount of spunlace nonwoven fabrics also produced. However, polypropylene nonwoven fabrics have poor hydrophilicity and hygroscopicity, with a water contact angle typically around 130°, which limits their application areas. For example, their use is restricted in areas such as wet wipes, face masks, medical gauze, wastewater treatment, filter cloths, and functionalized polypropylene nonwoven fabrics. Therefore, the preparation of polypropylene nonwoven fabrics with hydrophilic and water-retaining properties has become a research hotspot in both academia and industry.

[0003] To improve the hydrophilicity of polypropylene nonwoven fabrics, various technologies have been developed. Published papers and patents related to the preparation of hydrophilic polypropylene nonwoven fabrics mainly involve surface modification, radiation grafting, plasma modification, and hydrophilic finishing. For example, coating polypropylene nonwoven fabrics with hydrophilic inorganic substances, coating or grafting small molecule compounds can improve the hydrophilicity of polypropylene nonwoven fabrics to a certain extent, but it cannot retain water, and the degree of hydrophilicity needs to be further reduced. Alternatively, grafting a certain amount of hydrophilic polymers onto polypropylene nonwoven fabrics results in a reduced water contact angle, but it is still as high as 60°. Or, immersing polypropylene nonwoven fabrics in a hydrophilic polymer aqueous solution for a long time can also improve the hydrophilicity of polypropylene nonwoven fabrics to a certain extent, but the water contact angle of the modified polypropylene nonwoven fabric does not reach 0 degrees, and the hydrophilicity needs to be further reduced. For example, CN112626856A reports a polydopamine-coated modified polypropylene nonwoven fabric with a preferred water contact angle of 23.12°; CN107574665A reports a method for irradiating and grafting acrylamide to modify polypropylene nonwoven fabric with a preferred water contact angle of 32°; CN111519439A reports a method for modifying polypropylene nonwoven fabric with a dopamine-sodium alginate mixture with a preferred water contact angle of 32.17°.

[0004] Clearly, hydrophilic modification of polypropylene nonwoven fabrics has received widespread attention and development in this field. However, the hydrophilicity of modified polypropylene nonwoven fabrics still needs to be further reduced. In particular, there are no reports on polypropylene nonwoven fabrics with a water contact angle of 0 degrees and water retention function. Therefore, how to further improve the hydrophilic and water-retaining properties of polypropylene nonwoven fabrics remains a research hotspot and direction in this field. Summary of the Invention

[0005] To address the technical problems existing in the prior art, this invention provides a polypropylene fiber cloth with hydrophilic and water-retaining functions, its preparation method, and its applications. This polypropylene fiber cloth exhibits good hydrophilic and water-retaining properties, achieving a static contact angle of 0 degrees with water. After contact with water, the polypropylene fiber cloth has a higher liquid content and better water retention performance, further broadening the application range of polypropylene fiber cloth. Furthermore, the method for preparing this polypropylene fiber cloth does not require any pretreatment such as grafting modification; it directly obtains the hydrophilic and water-retaining polypropylene fiber cloth of this invention through contact with a hydrophilic polymer and with the aid of external force. This method is characterized by high efficiency, low consumption, and low cost.

[0006] In a first aspect, the object of the present invention is to provide a polypropylene fiber cloth, comprising a polypropylene fiber cloth matrix and a hydrophilic polymer; wherein the hydrophilic polymer is loaded on the surface of the fibers of the polypropylene fiber cloth matrix and optionally loaded in the pores of the fibers; wherein the fiber diameter of the polypropylene fiber cloth is less than 25 micrometers, that is, the fiber diameter of the polypropylene fiber cloth obtained after loading the polypropylene fiber cloth matrix with the hydrophilic polymer is less than 25 micrometers.

[0007] In a preferred embodiment of the present invention, the fiber diameter in the polypropylene fiber cloth is less than 20 micrometers, preferably less than 10 micrometers.

[0008] The range of fiber diameters in the polypropylene fiber cloth described in this invention refers to statistically obtained values. All polypropylene fiber cloths whose statistically obtained values ​​fall within the scope of this invention are included in this invention. However, it is not excluded that there may be occasional instances where the diameters of some (or a few) fibers on the overall polypropylene fiber cloth matrix are outside the range specified in this application. The fiber diameter detection method described above can employ conventional methods in the art, including but not limited to observing the fibers under a microscope, such as an electron microscope or an optical microscope, and measuring and statistically analyzing the fiber diameter.

[0009] According to the present invention, the mass content of the hydrophilic polymer in the polypropylene fiber cloth can be selected within a wide range. In a preferred embodiment of the present invention, based on the total mass of the polypropylene fiber cloth as 100%, the content of the polypropylene fiber cloth matrix in the polypropylene fiber cloth is 80%-99.9%, preferably 90%-99.9%; and the content of the hydrophilic polymer is 0.1%-20%, preferably 0.1%-10%.

[0010] According to the present invention, based on the total mass of the polypropylene fiber cloth as 100%, the content of the polypropylene fiber cloth matrix in the polypropylene fiber cloth is more preferably 90%-99.9%, for example, it can be 90%, 93%, 95%, 97%, 98.3%, 99.9%, and any two values ​​or any range of any two values.

[0011] According to the present invention, the content of the hydrophilic polymer is more preferably 0.1%-10% based on the total mass of the polypropylene fiber cloth as 100%. For example, 0.1%, 1%, 1.7%, 3%, 5%, 7%, 8%, 10%, and any two values ​​or any range of any two values.

[0012] According to the present invention, the content of the hydrophilic polymer in the polypropylene fiber cloth can be detected using conventional detection methods in the art. These methods include, but are not limited to, the following: weigh the unmodified polypropylene fiber cloth (m1), treat it according to the methods listed in the examples, and then dry it to obtain the treated polypropylene fiber cloth (m2). The mass content of the hydrophilic polymer is calculated as (m2-m1) / m2×100%.

[0013] According to the present invention, the selectable range of hydrophilic polymer content per unit surface area of ​​the polypropylene fiber cloth is relatively wide. In a preferred embodiment of the present invention, the hydrophilic polymer content per unit surface area of ​​the polypropylene fiber cloth is 0.005 g / m². 2 -8g / m 2 Preferably, it is 0.01 g / m 2 -4g / m 2 More preferably 0.5-3 g / m 2 For example, 0.5g / m 2 1g / m 2 2g / m 2 3g / m 2 And any two values ​​or any interval of any two values. According to the present invention, the content of hydrophilic polymer in the unit surface area of ​​the polypropylene fiber cloth can be detected by conventional detection methods in the art. Including but not limited to the following methods: First, the sample to be tested is coated with gold on the surface, and then the coated sample is placed on the SEM detection stage. The 5μm×5μm area on the sample is scanned with SEM, and then the oxygen mass fraction of the polypropylene fiber cloth before modification and the polypropylene fiber cloth after hydrophilic modification is determined by EDS energy dispersive spectroscopy in this area, and recorded as w0 and w1 respectively. The oxygen mass fraction is calculated according to the following formula: W=(w1-w0) / (M O / M A )×M, where M O M is the relative atomic mass of oxygen. AM is the molecular weight of a single hydrophilic polymer unit, M is the areal density of the polypropylene fiber cloth, and W is the content of hydrophilic polymer per unit area of ​​the polypropylene fiber cloth.

[0014] According to the present invention, the polypropylene fiber fabric matrix can be selected from a wide range of materials, such as meltblown polypropylene nonwoven fabric, spunbond polypropylene nonwoven fabric, spunlace polypropylene nonwoven fabric, etc. In a preferred embodiment of the present invention, the polypropylene nonwoven fabric matrix is ​​polypropylene meltblown nonwoven fabric.

[0015] According to the present invention, the range of selectable hydrophilic polymers is wide. In a preferred embodiment of the present invention, the hydrophilic polymer is capable of absorbing water, and preferably, after absorbing water, it is loaded in the form of a hydrogel in the surface and pores of the polypropylene fiber cloth matrix.

[0016] In a more preferred embodiment of the present invention, the hydrophilic polymer is selected from water-soluble polymers, preferably at least one of the following polymers and / or at least one of the following polymers formed with a crosslinking agent to form a crosslinked polymer: polyvinyl alcohol, polyacrylamide, polyethyleneimine, sodium polyacrylate, polyacrylic acid, maleic anhydride copolymer and its derivatives, and polyethylene glycol, more preferably at least one of sodium polyacrylate, maleic anhydride copolymer and its derivatives, polyvinyl alcohol, and polyethylene glycol.

[0017] According to the present invention, the crosslinking agent can be selected from a wide range. In a preferred embodiment of the present invention, the crosslinking agent is selected from at least one of polybasic acids and polybasic aldehydes, including but not limited to at least one of glutaraldehyde and boric acid, and more preferably glutaraldehyde.

[0018] In a preferred embodiment of the present invention, the static contact angle between the polypropylene fiber cloth and water can reach 0-30 degrees, preferably the static contact angle between the polypropylene fiber cloth and water can reach 0 degrees.

[0019] According to the present invention, the static contact angle of the polypropylene fiber cloth with water and the test of the static contact angle reaching 0 degrees can be performed using conventional testing methods in the art. These methods include, but are not limited to, the following: The fiber cloth sample is flatly attached to a glass slide, ensuring the sample remains horizontal during attachment. The slide is then fixed on the sample stage of a contact angle measuring instrument. The instrument is adjusted to control a water droplet volume of 5 μL, which is dropped into the center of the sample. The angle at the three-phase interface from the solid-liquid interface through the interior of the droplet to the vapor-liquid interface is measured; this is the static contact angle (abbreviated as water contact angle).

[0020] In a preferred embodiment of the present invention, since the polypropylene fiber cloth is hydrophilic, its overall mass increases upon contact with water due to its hydrophilicity and water absorption. This increase in mass is related to factors such as the fiber thickness, the hydrophilic polymer (e.g., PVA), and the degree of cross-linking. In this invention, the increase in mass due to water can be controlled through process control. Based on actual needs, taking the total mass of the polypropylene fiber cloth as 1 part, the present invention controls the process to ensure that the mass of water added to the fiber cloth after contact with water is 2-6 parts, preferably 3-5 parts, such as 3.5 parts, 4 parts, 4.5 parts, 5 parts, or any two values ​​or any range between any two values.

[0021] According to the present invention, the increase in water mass (liquid content) after the polypropylene fiber cloth comes into contact with water can be detected using conventional testing methods in the art. These methods include, but are not limited to, the following: Take a dried hydrophilic polypropylene fiber cloth and weigh it. Then, rinse the sample with deionized water until no foam remains, suspend it at 25°C and 30% humidity, and after one minute without any water droplets falling, weigh it again. The difference between the two weighings, divided by the mass after drying, is the liquid content of the sample. The total mass of the polypropylene fiber cloth can be considered as one part, expressed as a multiple.

[0022] In a preferred embodiment of the present invention, the water retention rate of the polypropylene fiber cloth is 10-60 wt%, preferably 30-50 wt%. Here, the water retention rate refers to the water content in the fully soaked hydrophilic polypropylene fiber cloth, calculated as 100 wt%, after natural drying.

[0023] According to the present invention, the water retention rate of the polypropylene fiber cloth can be tested using conventional testing methods in the art. These methods include, but are not limited to, the following: Take a complete piece of impregnated hydrophilic polypropylene fiber cloth, weigh its wet weight m1, place the weighed polypropylene fiber cloth at room temperature and allow it to air dry naturally. After half an hour, weigh the mass m2 of the hydrophilic polypropylene fiber cloth. m1-m2 represents the water loss, and the water loss rate is calculated as (m1-m2) / (m1-m0), where m0 is the dry weight of the dried hydrophilic polypropylene fiber cloth. The water retention rate is calculated as (m2-m0) / (m1-m0).

[0024] Secondly, the object of the present invention is to provide a method for preparing the polypropylene fiber cloth described in the first aspect, comprising contacting the polypropylene fiber cloth matrix with a solution containing a hydrophilic polymer, and loading the hydrophilic polymer onto the surface of the fibers of the polypropylene fiber cloth matrix and optionally onto the pores of the fibers under the action of an external force; wherein the fiber diameter of the polypropylene fiber cloth matrix is ​​less than 25 micrometers, preferably less than 20 micrometers, and more preferably less than 10 micrometers.

[0025] The fiber diameter range of the polypropylene fiber fabric matrix described in this invention refers to the nominal fiber diameter range or statistically obtained value of commercially available polypropylene fiber fabric matrices in the art. Where the nominal fiber diameter range or statistically obtained value is within the scope of this invention, and there are occasionally some (or a few) fibers in the overall polypropylene fiber fabric matrix whose diameter range is outside the range specified in this application, this also falls within the protection scope of this invention. The fiber diameter detection method described above can employ conventional testing methods in the art, including but not limited to observing the fibers under a microscope, such as an electron microscope or an optical microscope, and measuring and statistically analyzing the fiber diameter.

[0026] Based on the preparation method of the present invention, after the polypropylene fiber cloth matrix is ​​loaded with a hydrophilic polymer under the action of external force, the fiber diameter of the obtained polypropylene fiber cloth remains basically unchanged. Under the observation of scanning electron microscopy, no obvious thickening of the fibers is observed, and the fiber diameter can still be maintained within the range of the fiber diameter of the polypropylene fiber cloth matrix.

[0027] The method for preparing the polypropylene fiber cloth of the present invention does not require any pretreatment such as grafting modification of the polypropylene fiber cloth. It can be obtained by directly contacting the polypropylene fiber cloth with hydrophilic and water-retaining functions with external force. The method is characterized by high efficiency, low consumption and low cost.

[0028] In a preferred embodiment of the present invention, the manner in which the external force is applied is not specifically limited, and may include, but is not limited to, at least one of ultrasonication, rolling, lamination, molding, and vacuum filtration. According to the present invention, the temperature of the external force application can be selected within a wide range, preferably not exceeding the melting temperature of polypropylene and the hydrophilic polymer, and more preferably not exceeding the glass transition temperature of the hydrophilic polymer.

[0029] In a more preferred embodiment of the present invention, the preparation method includes the following steps:

[0030] The polypropylene fiber cloth matrix is ​​immersed in a solution containing a hydrophilic polymer, and the solution containing the hydrophilic polymer is then immersed into the polypropylene fiber cloth matrix by external force to obtain a polypropylene fiber cloth matrix loaded with a hydrophilic polymer.

[0031] According to the present invention, the rolling temperature does not exceed the melting temperature of polypropylene and hydrophilic polymer, more preferably does not exceed the glass transition temperature of hydrophilic polymer, even more preferably 10°C to 50°C, and more preferably room temperature (about 25°C to 35°C).

[0032] According to the present invention, the mass fraction of the hydrophilic polymer in the solution containing the hydrophilic polymer in step (1) can be selected within a wide range. In a preferred embodiment of the present invention, in step (1), the mass fraction of the hydrophilic polymer in the solution containing the hydrophilic polymer is 0.5-15 wt%, preferably 1-10 wt%, more preferably 5-10 wt%, for example 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt%, and any two values ​​or any range of any two values.

[0033] In a preferred embodiment of the present invention, the hydrophilic polymer is selected from water-soluble polymers, preferably at least one of polyvinyl alcohol, polyacrylic acid, sodium polyacrylate, polyethylene glycol, maleic anhydride copolymer and its derivatives, and polyacrylamide, and more preferably at least one of polyvinyl alcohol, sodium polyacrylate and polyethyleneimine.

[0034] According to the present invention, there is no particular limitation on the molecular weight of the hydrophilic polymer; for example, the number average molecular weight can be 30,000-300,000. Taking the embodiments of the present invention below as examples, polyvinyl alcohol with a degree of polymerization of 1700 can be selected, sodium polyacrylate with a number average molecular weight of 260,000-270,000 can be selected, and maleic anhydride copolymers and their derivatives with a number average molecular weight of 260,000-350,000 can also be selected.

[0035] According to the present invention, the polypropylene fiber fabric matrix can be selected from a wide range of materials, such as meltblown polypropylene nonwoven fabric, spunbond polypropylene nonwoven fabric, spunlace polypropylene nonwoven fabric, etc. In a preferred embodiment of the present invention, the polypropylene nonwoven fabric matrix is ​​polypropylene meltblown nonwoven fabric.

[0036] The polypropylene meltblown fiber cloth can be selected from a wide range of options. Preferably, the areal density of the polypropylene meltblown fiber cloth is 10-60 g / m². 2 Preferably 20-50g / m 2 .

[0037] Preferably, the diameter of the polypropylene fiber matrix is ​​less than 10 micrometers.

[0038] According to the present invention, the conditions for the application of external force are wide-ranging, such as the processing time, the number of processing times, and the process conditions of the processing method, without specific limitations.

[0039] The ultrasonic treatment conditions in this invention can be selected over a wide range. In a preferred embodiment of this invention, the ultrasonic treatment conditions in step (1) include: the ultrasonic frequency is not less than 5 kHz, preferably not less than 10 kHz; for example, 10 kHz, 20 kHz, 30 kHz, 40 kHz, 45 kHz, 50 kHz, 55 kHz, and 60 kHz. The higher the ultrasonic power, the less processing time and the fewer processing times are required.

[0040] According to the present invention, the ultrasonic processing equipment can be selected from conventional ultrasonic processing equipment, including but not limited to ultrasonic cleaning tables, cell disruptors, ultrasonic probes, industrial ultrasonic devices, etc. The present invention does not particularly limit the power of the specific ultrasonic processing equipment; preferably, the power is 50-750W, more preferably 50-500W, and even more preferably 150-350W.

[0041] According to the present invention, the ultrasonic treatment time in the preparation step can be selected within a wide range. In a preferred embodiment of the present invention, the ultrasonic time is not less than 1 minute, preferably not less than 5 minutes, and more preferably 10-120 minutes.

[0042] In another preferred embodiment of the present invention, the filtration conditions can be selected over a wide range, and the processing time and number of processes can be reduced as the vacuum level increases. In a preferred embodiment of the present invention, the filtration conditions include: a vacuum level of not less than 5 Pa, preferably not less than 10 Pa, for example, 10 Pa, 20 Pa, 30 Pa, 40 Pa, or 50 Pa; and / or, a filtration time of not less than 1 second, preferably not less than 5 seconds. Preferably, the hydrophilic polymer solution remains wetted in the polypropylene fiber cloth matrix until filtration is stopped.

[0043] In another preferred embodiment of the present invention, the conditions for roller pressing include: pressure not less than 5 Pa, preferably not less than 10 Pa, for example, 10 Pa, 20 Pa, 30 Pa, 40 Pa, 50 Pa, etc.; and the number of roller pressing cycles not less than 1 time, for example, 1 time, 2 times, 3 times, etc.

[0044] This invention includes an optional crosslinking step, in which the resulting polypropylene fiber cloth can be used in disposable hydrophilic products without crosslinking.

[0045] The preparation method, including the crosslinking step, employs the following method for the crosslinking reaction: the polypropylene fiber cloth obtained after external force treatment is contacted with a solution containing a crosslinking agent to carry out the crosslinking reaction. According to the present invention, the range of selectable crosslinking agents is wide. In a preferred embodiment of the present invention, the crosslinking agent is selected from at least one of polybasic acids and polybasic aldehydes, preferably at least one of glutaraldehyde and boric acid, and more preferably glutaraldehyde. This method of loading first and then crosslinking allows the hydrophilic polymer to be uniformly dispersed on and around the fiber surface of the polypropylene fiber cloth matrix. The crosslinked hydrophilic polymer forms a network structure, increasing its stability in the fiber cloth and improving its hydrophilic stability. Furthermore, with the appearance of the crosslinked structure, the hydrophilic polymer swells but does not dissolve upon contact with water, extending the water retention time. Therefore, the water absorption and retention properties of crosslinked and uncrosslinked products are significantly different, making them suitable for applications with different requirements.

[0046] The hydrophilic stability refers to the change in contact angle after the hydrophilic fiber cloth is completely immersed in deionized water and treated under ultrasonic cleaning conditions for 5 minutes, repeated 3 times. The smaller the change in contact angle, the better its hydrophilic stability. The water retention time refers to the time required for the hydrophilic fiber cloth to absorb water and for the water to completely evaporate.

[0047] According to the present invention, the mass fraction of the crosslinking agent in the solution containing the crosslinking agent can be selected within a wide range. In a preferred embodiment of the present invention, the content of the crosslinking agent in the solution containing the crosslinking agent is 0.005-2 wt%, preferably 0.01-1 wt%.

[0048] According to the present invention, the range of selectable crosslinking conditions is relatively wide. In a preferred embodiment of the present invention, the crosslinking conditions include: a crosslinking temperature of 20-85°C, preferably 50-80°C.

[0049] According to the present invention, the crosslinking time can be selected within a wide range. In a preferred embodiment of the present invention, the crosslinking time is 0.1h-2h, preferably 0.1h-1.5h.

[0050] According to the present invention, the pH range of the solution containing the crosslinking agent is relatively wide. In a preferred embodiment of the present invention, the pH of the solution containing the crosslinking agent is less than 7, preferably 4-7. The present invention does not impose any particular limitation on the raw materials used to adjust the pH; conventional acid and base raw materials in the art can be used.

[0051] In a preferred embodiment of the present invention, the method further includes a step of cleaning and / or drying the polypropylene fiber cloth prepared by the aforementioned method.

[0052] The present invention does not impose any particular limitations on the cleaning method, including but not limited to rinsing with water. To improve cleaning efficiency, ultrasonic cleaning is preferred. The ultrasonic conditions are not particularly limited here. For example, the ultrasonic frequency is 20-80 kHz. Preferably, the ultrasonic cleaning time is 1-30 minutes per cycle, more preferably 15-25 minutes per cycle, and the number of cleaning cycles is selected from 1-5 times, preferably 2-4 times.

[0053] In one specific embodiment of the present invention, the preparation process of the polypropylene fiber cloth includes the following steps: preparing a hydrophilic polymer aqueous solution, immersing the polypropylene fiber cloth in the hydrophilic polymer solution, placing it in an ultrasonic device for ultrasonic treatment; or, immersing the polypropylene fiber cloth in the hydrophilic polymer solution for vacuum filtration; or, pressing it with rollers; optionally crosslinking the treated polypropylene fiber cloth, followed by optional washing and drying, to obtain a polypropylene fiber cloth with hydrophilic and water-retaining functions.

[0054] Thirdly, the object of the present invention is to provide a polypropylene fiber cloth prepared according to the preparation method described in the second aspect.

[0055] Fourthly, the object of the present invention is to provide the application of the polypropylene fiber cloth described in either the first or third aspect in moisturizing products or wastewater treatment.

[0056] According to the present invention, moisturizing products include, but are not limited to, wet wipes, medical dressings, and facial masks; wastewater treatment includes, but is not limited to, filtering larger particles and adsorbing harmful metal ions.

[0057] Compared with the prior art, the present invention has the following advantages:

[0058] The polypropylene fiber cloth of this invention has good hydrophilicity and water retention properties. Preferably, the water contact angle of this hydrophilic polypropylene fiber cloth can reach 0 degrees, and the liquid content after contact with water can reach more than 4 times the weight of the polypropylene fiber cloth before water absorption. The polypropylene fiber cloth of this invention can be used in moisturizing products or wastewater treatment, further broadening the application range of polypropylene fiber cloth.

[0059] The polypropylene fiber cloth of the present invention possesses the above-mentioned properties because the inventors discovered through research that the polypropylene fiber cloth of the present invention comprises a polypropylene fiber cloth matrix and a hydrophilic polymer; the hydrophilic polymer is loaded on the surface and pores of the polypropylene fiber cloth matrix. After contact with water, the hydrophilic polymer can form a hydrogel loaded in the pores of the polypropylene fiber cloth fibers. On the one hand, it enhances the capillary effect of the pores, allowing the static contact angle of water to quickly reach 0 degrees. On the other hand, it improves the water retention capacity of the polypropylene fiber cloth, and the liquid content after contact with water can reach more than 4 times the weight of the polypropylene fiber cloth before water absorption.

[0060] Moreover, the method for preparing the polypropylene fiber cloth of the present invention does not require any pretreatment such as grafting modification of the polypropylene fiber cloth, and the method is characterized by high efficiency, low consumption and low cost. Attached Figure Description

[0061] Figure 1 These are SEM (scanning electron microscope) images of the polypropylene fiber cloth in the blank sample (comparative example 2) at different scales.

[0062] Figure 2 These are SEM images of the polypropylene fiber cloth in Example 1 at different scales.

[0063] Figure 3 These are SEM images of the polypropylene fiber cloth in Example 2 at different scales.

[0064] Figure 1 As shown in the electron micrograph of the blank sample, the surface of the polypropylene fiber cloth is smooth, and no filaments, membranes, or other structures are observed in the interfiber spaces. Figure 2 , Figure 3 As shown, the modified polypropylene fiber cloth in Examples 1 and 2 has a rougher fiber surface and contains membranes and filaments in the fiber gaps. These structures indicate that polyvinyl alcohol was successfully introduced into the fiber surface and fiber gaps of the polypropylene fiber cloth.

[0065] As can be seen from the above figures, the fiber diameter of the polypropylene fiber cloth matrix in this invention is relatively small, and the fiber diameter of the polypropylene fiber cloth obtained after the treatment of this invention does not change significantly, has no significant effect on the pore size, and the reduction in pore size is not obvious.

[0066] The present invention employs a specific preparation method, which involves pre-impregnating a hydrophilic polymer with external force and then optionally cross-linking, to uniformly disperse the hydrophilic polymer around the surface of the fiber cloth, resulting in a more uniform distribution of the hydrophilic polymer. Detailed Implementation

[0067] The present invention will now be described in detail with reference to specific embodiments. It should be noted that the following embodiments are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the content of the present invention are still within the scope of protection of the present invention.

[0068] In the following examples, the polypropylene fiber cloth is made of polypropylene nonwoven fabric.

[0069] The experimental data in the examples were measured using the following instruments and methods:

[0070] The water contact angle obtained in the example was measured using the German EASYDROP contact angle tester: The non-woven fabric was cut into a sample of 1cm×1cm size, and then the sample was flatly attached to a glass slide. During the attachment process, care was taken to keep the sample flat in the horizontal direction. The glass slide was then placed on the sample stage of the EASYDROP contact angle measuring instrument and fixed. The instrument was adjusted to control the volume of 5μL water droplet to the center of the sample. After 10 seconds, the angle between the solid-liquid interface, through the interior of the droplet, and to the vapor-liquid interface at the three-phase interface was measured, which is the static contact angle (abbreviated as water contact angle).

[0071] Liquid content of hydrophilic polypropylene nonwoven fabric: Take a dry hydrophilic polypropylene nonwoven fabric and weigh it. Then rinse the sample with deionized water until there is no foam, and hang it at 25°C and 30% humidity. After no water droplets fall for 1 minute, weigh it again. The difference between the two weighings divided by the mass after drying is the liquid content of the sample, expressed in multiples.

[0072] Water retention rate of polypropylene nonwoven fabric obtained in the example: Take a complete piece of wetted hydrophilic polypropylene nonwoven fabric and weigh it to obtain its wet weight m1. Place the weighed polypropylene nonwoven fabric at room temperature and let it air dry naturally. After half an hour, weigh the mass m2 of the hydrophilic polypropylene nonwoven fabric. m1-m2 is the water loss. Water loss rate = (m1-m2) / (m1-m0), where m0 is the dry weight of the dried hydrophilic polypropylene nonwoven fabric. Water retention rate = (m2-m0) / (m1-m0).

[0073] The mass content of hydrophilic polymer in the polypropylene nonwoven fabric obtained in the example: Weigh the unmodified polypropylene nonwoven fabric by mass m1, process it by the method listed in the example and dry it to obtain the processed polypropylene nonwoven fabric, weigh it by mass m2, and (m2-m1) / m2×100% is the mass content of hydrophilic polymer.

[0074] The content of hydrophilic polymer per unit surface area of ​​the polypropylene nonwoven fabric was determined as follows: First, the sample to be tested was coated with a gold coating. Then, the coated sample was placed on an SEM detection stage, and a 5μm × 5μm area on the sample was scanned using SEM. Then, the oxygen mass fraction of the unmodified and hydrophilically modified polypropylene nonwoven fabrics in this area was determined using EDS energy dispersive spectroscopy, denoted as w0 and w1 respectively. The oxygen mass fraction was calculated using the following formula: W = (w1 - w0) / (M O / M A )×M, where M O M is the relative atomic mass of oxygen. A M is the molecular weight of a single hydrophilic polymer unit, M is the areal density of the polypropylene nonwoven fabric, and W is the content of hydrophilic polymer per unit area of ​​the polypropylene nonwoven fabric.

[0075] In the following examples, polyvinyl alcohol (PVA-1799), with a degree of polymerization of 1700 and a degree of alcoholysis of 99%, was purchased from Aladdin. Unless otherwise specified, the polypropylene meltblown nonwoven fabric used in the examples and comparative examples was from Sinopec Yanshan Petrochemical, with an areal density of 25 g / m³. 2 The fiber diameter is 0.5-8 micrometers.

[0076] Sodium polyacrylate, purchased from Aladdin, CP grade, number average molecular weight 260,000-270,000, 80 mesh.

[0077] In the following examples, unless otherwise specified, the experimental temperatures involved, including those for roller pressing, are all conducted at room temperature (25°C).

[0078] Example 1

[0079] Polypropylene meltblown nonwoven fabric was immersed in a 5 wt% polyvinyl alcohol aqueous solution and ultrasonically treated for 20 minutes at a frequency of 50 kHz under a 250 W ultrasonic probe. The treated polypropylene meltblown fabric was then crosslinked in a 0.5 wt% glutaraldehyde crosslinking solution (pH 6) in a 60 °C oven for 1 h. After crosslinking, the polypropylene meltblown fabric was cleaned three times in a 100 W ultrasonic water bath at a frequency of 50 kHz, each time for 20 minutes, and then dried (at 60 °C for 1 h).

[0080] The obtained polypropylene nonwoven fabric was tested for water contact angle, liquid content, water retention rate, mass content of hydrophilic polymer, fiber diameter and hydrophilic polymer content per unit area. The specific test data are shown in Table 1.

[0081] Example 2

[0082] Except for changing the concentration of the PVA aqueous solution to 1 wt%, the other operations were the same as in Example 1. The specific test data are shown in Table 1.

[0083] Example 3

[0084] Except for changing the ultrasonic treatment time when soaking in polyvinyl alcohol aqueous solution to 50 minutes, all other aspects were the same as in Example 1. Specific test data are shown in Table 1.

[0085] Example 4

[0086] Polypropylene nonwoven fabric was prepared according to the method in Example 1, except that the polyvinyl alcohol solution was replaced with an aqueous solution of sodium polyacrylate of equal mass concentration. Specific test data are shown in Table 1.

[0087] Example 5

[0088] Polypropylene meltblown nonwoven fabric was laid flat in a Buchner funnel. 50 ml of 5 wt% PVA solution was added to the funnel, and vacuum filtration was performed at a vacuum level of 10 Pa. Filtration was stopped when only 10 ml of PVA solution remained in the funnel. The treated polypropylene nonwoven fabric was then immersed in a 0.5 wt% acidic glutaraldehyde solution (pH 6) and crosslinked in a 60°C oven for 1 hour. After crosslinking, the fabric was placed in a 100W ultrasonic water bath and cleaned three times at a frequency of 50 kHz for 20 minutes each time. Finally, it was dried. Specific test data are shown in Table 1.

[0089] Example 6

[0090] Polypropylene nonwoven fabric was prepared according to the method of Example 1, except that the crosslinking agent was replaced with boric acid with a mass fraction of 0.5 wt%. All other operations were the same as in Example 1. Specific test data are shown in Table 1.

[0091] Example 7

[0092] Polypropylene nonwoven fabric was prepared according to the method of Example 1, except that the crosslinking agent concentration was changed to 0.1 wt%. All other operations were the same as in Example 1. Specific test data are shown in Table 1.

[0093] Example 8

[0094] Polypropylene nonwoven fabric was prepared according to the method in Example 1, except that the treatment method was changed to roller pressing. A self-made roller pressing device was used, with both upper and lower rollers having a diameter of 50 mm and a soft rubber surface. The roller pressing process was carried out below the surface of the polymer aqueous solution, with a pressure of 100 kPa between the rollers. The roller pressing process was repeated twice. The treated polypropylene nonwoven fabric was immersed in a 0.5 wt% acidic glutaraldehyde solution (pH 6) and crosslinked in a 60°C oven for 1 hour. After crosslinking, it was placed in a 100W ultrasonic water bath and cleaned three times at a frequency of 50 kHz for 20 minutes each time, and finally dried. Specific test data are shown in Table 1.

[0095] Comparative Example 1

[0096] Polypropylene meltblown nonwoven fabric (same as in Example 1) was soaked in 5wt% PVA solution for 20 minutes and then taken out. It was then washed three times in a 100W ultrasonic water bath at a frequency of 50kHz for 20 minutes each time, and then dried. It is a non-hydrophilic material. The specific test data are shown in Table 1.

[0097] Comparative Example 2

[0098] Take polypropylene meltblown nonwoven fabric (same as in Example 1), soak it in deionized water, and place it under a 250W ultrasonic probe to be ultrasonically treated at a frequency of 50kHz for 20 minutes. Then immerse the polypropylene meltblown fabric in the same crosslinking agent solution as in Example 1, and crosslink it at 60℃ for 1 hour. After crosslinking is completed, take it out, clean it three times in an ultrasonic water bath at a frequency of 50kHz, 20 minutes each time, and dry it. It is a non-hydrophilic material. Specific test data are shown in Table 1.

[0099] Example 9

[0100] Take polypropylene meltblown nonwoven fabric, soak it in 5wt% PVA solution, place it under a 250W ultrasonic probe and ultrasonically treat it at a frequency of 50kHz for 20 minutes, then press it twice with a roller, and then clean it three times in a 100W ultrasonic water bath at a frequency of 50kHz, each time for 20 minutes, and then dry it after cleaning.

[0101] The liquid content, water contact angle, and water loss rate were tested. Although the water contact angle could reach 0° in a short time due to the lack of cross-linking treatment, the water absorption was much smaller than that of Example 1 under the same conditions. Specific test data are shown in Table 1.

[0102] Example 10

[0103] Polypropylene nonwoven fabric was prepared according to the method in Example 1, except that the concentration of polyvinyl alcohol was 0.5 wt%. Specific test data are shown in Table 1.

[0104] Example 11

[0105] Polypropylene nonwoven fabric was prepared according to the method in Example 1, except that the ultrasonically treated polypropylene meltblown fabric was crosslinked in a 0.5 wt% glutaraldehyde crosslinking solution (pH 6) in a 60°C oven for 1 hour without a cleaning step. Specific test data are shown in Table 1.

[0106] Example 12

[0107] The preparation was carried out according to the method of Example 1, except that polypropylene meltblown nonwoven fabric was immersed in a 5 wt% polyvinyl alcohol aqueous solution and ultrasonically treated at a frequency of 70 kHz for 20 minutes. Specific test data are shown in Table 1.

[0108] Example 13

[0109] The preparation was carried out according to the method of Example 1, except that the polypropylene meltblown nonwoven fabric used was from Zhejiang Jiaxing Jiashan Hongfa Wool Industry Co., Ltd. (J002), with an areal density of 25 g / m². 2 The fiber diameter is 0.5-20 micrometers.

[0110] Example 14

[0111] The preparation was carried out according to the method of Example 1, except that the concentration of polyvinyl alcohol was 8 wt%.

[0112] Comparative Example 3

[0113] The preparation was carried out according to the method of Example 1, except that the polypropylene meltblown nonwoven fabric was replaced with polypropylene spunbond nonwoven fabric (Shandong Lingxiang New Material Co., Ltd., model YC188, 80g / m²). 2 (Fiber diameter 20-50 micrometers or) as a substitute. Test results are shown in Table 1.

[0114] Comparative Example 4

[0115] Polypropylene nonwoven fabric was prepared using the following method, the specific method being as follows:

[0116] A 0.8 wt% aqueous solution was prepared using PVA1750 (purchased from Shandong Jiaying Chemical Technology Co., Ltd.) and deionized water at 90℃. 500 ml of PVA solution was weighed and mixed with 600 ml of crosslinking solution to obtain a mixed solution. The crosslinking solution contained 45 ml of glutaraldehyde aqueous solution (50 wt%), as well as acetic acid aqueous solution (10 vol%), methanol aqueous solution (10 vol%), and sulfuric acid aqueous solution (10 vol%), with a volume ratio of 3:2:1. Polypropylene meltblown nonwoven fabric (Sinopec Yanshan Petrochemical, 25 g / m²) was then used. 2 The sample was placed in a mixed solution and vibrated at 150 rpm for 60 minutes at 50°C in a shaking incubator. It was then placed in deionized water for 1 hour to remove residual crosslinking agent and PVA, and finally dried in a 70°C oven for 1 hour. Specific test results are shown in Table 1.

[0117] Table 1

[0118]

[0119]

[0120] As shown in Table 1, the static contact angle between the polypropylene nonwoven fabric and water in this invention can reach 0 degrees. After contact with water, the liquid content of the polypropylene fiber fabric is higher, and the water retention performance is better. The liquid content can reach more than 2.55 times that of the nonwoven fabric before hydrophilization, and in some cases more than 4 times, showing good hydrophilicity. At the same time, the water retention rate of the polypropylene nonwoven fabric is above 30%, showing significant water retention performance. In contrast, the static contact angle between the modified polypropylene nonwoven fabric and water in the prior art is above 40 degrees. Compared with the polypropylene fiber fabric obtained by the prior art or conventional methods, the polypropylene fiber fabric of this invention has achieved significant technical effects and has made significant progress.

[0121] It should be noted that the embodiments described above are only for explaining the present invention and do not constitute any limitation on the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory terms, not limiting terms. Modifications can be made to the present invention within the scope of the claims, and revisions can be made to the present invention without departing from the scope and spirit of the present invention. Although the present invention described herein relates to specific methods, materials, and embodiments, it does not mean that the present invention is limited to the specific examples disclosed herein; on the contrary, the present invention can be extended to all other methods and applications with the same function.

[0122] All publications, patent applications, patents, and other references mentioned in this specification are incorporated herein by reference. Unless otherwise defined, all technical and scientific terms used in this specification have the meanings commonly understood by those skilled in the art. In case of conflict, the definitions in this specification shall prevail.

[0123] When this specification uses the prefixes “known to those skilled in the art,” “prior art,” or similar terms to derive materials, substances, methods, steps, apparatus, or components, the objects derived from such prefixes cover those commonly used in the art at the time of this application, but also include those that are not currently commonly used but will become generally recognized in the art as suitable for similar purposes.

[0124] The endpoints and any values ​​of the ranges disclosed in this application are not limited to the precise ranges or values; such ranges or values ​​should be understood to include values ​​close to them. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein. In principle, various technical solutions can be combined with each other to obtain new technical solutions, which should also be considered as specifically disclosed herein.

[0125] In the context of this specification, except where expressly stated otherwise, any matters or issues not mentioned shall apply directly to those known in the art without any modification.

[0126] Furthermore, any implementation described herein can be freely combined with one or more other implementations described herein, and the resulting technical solutions or technical ideas shall be regarded as part of the original disclosure or original record of the present invention, and should not be regarded as new content not disclosed or anticipated herein, unless those skilled in the art consider the combination to be obviously unreasonable.

Claims

1. A polypropylene fiber cloth with hydrophilic and water-retaining functions, comprising a polypropylene fiber cloth matrix and a hydrophilic polymer; wherein the hydrophilic polymer is loaded on the surface of the polypropylene fiber cloth matrix fibers and optionally loaded in the pores of the fibers; wherein the fiber diameter in the polypropylene fiber cloth is less than 25 micrometers; A method for preparing polypropylene fiber cloth includes contacting the polypropylene fiber cloth matrix with a solution containing a hydrophilic polymer, and loading the hydrophilic polymer onto the surface of the fibers of the polypropylene fiber cloth matrix and optionally into the pores of the fibers under the action of an external force, wherein the hydrophilic polymer is selected from water-soluble polymers and does not contain a crosslinking agent. The polypropylene fiber cloth obtained after treatment is brought into contact with a solution containing a crosslinking agent to carry out a crosslinking reaction, thereby obtaining the polypropylene fiber cloth with hydrophilic and water-retaining functions. The hydrophilic polymer is selected from at least one of polyvinyl alcohol, polyacrylamide, polyethyleneimine, sodium polyacrylate, polyacrylic acid, maleic anhydride copolymer, and polyethylene glycol.

2. The polypropylene fiber cloth according to claim 1, characterized in that: The polypropylene fiber cloth has a fiber diameter of less than 10 micrometers; and / or, Based on the total mass of the polypropylene fiber cloth as 100%, the content of the polypropylene fiber cloth matrix in the polypropylene fiber cloth is 80%-99.9%; the content of the hydrophilic polymer is 0.1%-20%; and / or, The content of hydrophilic polymer per unit surface area of ​​the polypropylene fiber cloth is 0.005 g / m². 2 -8g / m 2 .

3. The polypropylene fiber cloth according to claim 1, characterized in that: Based on the total mass of the polypropylene fiber cloth as 100%, the content of the polypropylene fiber cloth matrix in the polypropylene fiber cloth is 90%-99.9%; the content of the hydrophilic polymer is 0.1%-10%; and / or, The content of hydrophilic polymer per unit surface area of ​​the polypropylene fiber cloth is 0.01 g / m². 2 -4g / m 2 .

4. The polypropylene fiber cloth according to claim 1, characterized in that: The content of hydrophilic polymer per unit surface area of ​​the polypropylene fiber cloth is 0.5-3 g / m². 2 .

5. The polypropylene fiber cloth according to claim 1, characterized in that: The polypropylene fiber fabric matrix is ​​polypropylene meltblown nonwoven fabric; and / or... The hydrophilic polymer is capable of absorbing water.

6. The polypropylene fiber cloth according to claim 1, characterized in that: The hydrophilic polymer is capable of absorbing water, and after absorbing water, it is loaded in the form of a hydrogel on the surface and in the pores of the polypropylene fiber fabric matrix.

7. The polypropylene fiber cloth according to claim 1, characterized in that: The hydrophilic polymer on the polypropylene fiber cloth is a crosslinked polymer formed by at least one of the following polymers and a crosslinking agent: At least one of polyvinyl alcohol, polyacrylamide, polyethyleneimine, sodium polyacrylate, polyacrylic acid, maleic anhydride copolymer, and polyethylene glycol.

8. The polypropylene fiber cloth according to claim 1, characterized in that: The hydrophilic polymer on the polypropylene fiber cloth is a crosslinked polymer formed by at least one of the following polymers and a crosslinking agent: At least one of sodium polyacrylate, polyvinyl alcohol, maleic anhydride copolymer, and polyethylene glycol.

9. The polypropylene fiber cloth according to claim 1, characterized in that: The crosslinking agent is selected from at least one of polybasic acids and polybasic aldehydes.

10. The polypropylene fiber cloth according to claim 1, characterized in that: The crosslinking agent is at least one of glutaraldehyde and boric acid.

11. The polypropylene fiber cloth according to claim 1, characterized in that: The crosslinking agent is glutaraldehyde.

12. The polypropylene fiber cloth according to any one of claims 1-11, characterized in that: The static contact angle between the polypropylene fiber cloth and water can reach 0-30 degrees; and / or, The polypropylene fiber cloth is hydrophilic, and with the total mass of the polypropylene fiber cloth as 1 part, the mass of water added after the polypropylene fiber cloth comes into contact with water is 2-6 parts; and / or, The water retention rate of the polypropylene fiber cloth is 10-60 wt%.

13. The polypropylene fiber cloth according to any one of claims 1-11, characterized in that: The static contact angle between the polypropylene fiber cloth and water can reach 0 degrees; and / or, The polypropylene fiber cloth is hydrophilic, and with a total mass of 1 part, the mass of water added to the polypropylene fiber cloth after contact with water is 3-5 parts; and / or, The water retention rate of the polypropylene fiber cloth is 30-50 wt%.

14. The polypropylene fiber cloth according to any one of claims 1-11, characterized in that: The polypropylene fiber cloth is hydrophilic, and with the total mass of the polypropylene fiber cloth as 1 part, the mass of water added after the polypropylene fiber cloth comes into contact with water is 3.5-5 parts.

15. A method for preparing polypropylene fiber cloth according to any one of claims 1-14, comprising contacting the polypropylene fiber cloth matrix with a solution containing a hydrophilic polymer, and loading the hydrophilic polymer onto the surface of the fibers of the polypropylene fiber cloth matrix and optionally onto the pores of the fibers under the action of an external force, wherein the hydrophilic polymer is selected from water-soluble polymers and does not contain a crosslinking agent. The polypropylene fiber cloth obtained after treatment is brought into contact with a solution containing a crosslinking agent to carry out a crosslinking reaction, thereby obtaining the polypropylene fiber cloth with hydrophilic and water-retaining functions. The fiber diameter of the polypropylene fiber cloth matrix is ​​less than 25 micrometers; The hydrophilic polymer is selected from at least one of polyvinyl alcohol, polyacrylamide, polyethyleneimine, sodium polyacrylate, polyacrylic acid, maleic anhydride copolymer, and polyethylene glycol.

16. The preparation method according to claim 15, characterized in that: The external force is applied in one or a combination of ultrasonic, vacuum filtration, rolling, lamination and molding methods.

17. The preparation method according to claim 15, characterized in that... Includes the following steps: The polypropylene fiber cloth matrix is ​​immersed in a solution containing a hydrophilic polymer, and the solution containing the hydrophilic polymer is then immersed into the polypropylene fiber cloth matrix by external force to obtain a polypropylene fiber cloth matrix loaded with a hydrophilic polymer.

18. The preparation method according to claim 15, characterized in that: The concentration of the hydrophilic polymer in the solution containing the hydrophilic polymer is 0.5-15 wt%; and / or, The hydrophilic polymer is at least one selected from polyvinyl alcohol, maleic anhydride copolymer, sodium polyacrylate, and polyethyleneimine; and / or, The areal density of the polypropylene fiber fabric matrix is ​​10-60 g / m³. 2 ; and / or, The polypropylene fiber cloth matrix has a fiber diameter of less than 10 micrometers.

19. The preparation method according to claim 15, characterized in that: The concentration of the hydrophilic polymer in the solution containing the hydrophilic polymer is 1-10 wt%; and / or, The areal density of the polypropylene fiber fabric matrix is ​​20-50 g / m³. 2 .

20. The preparation method according to claim 16, characterized in that: The conditions for ultrasonic treatment include: The ultrasound frequency is not less than 5 kHz, and / or the ultrasound duration is not less than 1 minute; and / or, The conditions for vacuum filtration include: The vacuum level is not less than 5 Pa and / or the filtration time is not less than 1 second, and / or The conditions for roller pressing include: The pressure shall not be less than 5 Pa; the number of roller pressing cycles shall not be less than 1.

21. The preparation method according to claim 16, characterized in that: The conditions for ultrasonic treatment include: The ultrasound frequency is not less than 10 kHz, and / or the ultrasound duration is not less than 5 minutes; and / or, The conditions for vacuum filtration include: The vacuum level is not less than 10 Pa, and / or the filtration time is not less than 5 seconds, and / or The conditions for roller pressing include: The pressure shall be no less than 10 Pa; the number of roller pressing cycles shall be no less than 1.

22. The preparation method according to claim 16, characterized in that: The ultrasound session lasts 10-120 minutes.

23. The preparation method according to claim 15, characterized in that: The crosslinking agent is selected from at least one of polybasic acids and polybasic aldehydes.

24. The preparation method according to claim 15, characterized in that: The crosslinking agent is at least one of glutaraldehyde and boric acid; and / or, The concentration of the crosslinking agent in the solution is 0.005-2 wt%; And / or, The crosslinking conditions include: a crosslinking temperature of 20-85℃; and / or a crosslinking time of 0.1h-2h; And / or, the pH of the solution containing the cross-linking agent is less than 7.

25. The preparation method according to claim 15, characterized in that: The crosslinking agent is glutaraldehyde; and / or, The concentration of the crosslinking agent in the solution is 0.01-1 wt%; and / or, The crosslinking conditions include: a crosslinking temperature of 50-80℃; and / or a crosslinking time of 0.1h-1.5h.

26. The use of the polypropylene fiber cloth according to any one of claims 1-14 in moisturizing products or wastewater treatment.

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