Hydrophilic composite non-woven fabric for wet tissue, cleaning wet tissue and wet tissue preparation method

Abstract

The invention discloses a hydrophilic composite non-woven fabric for wet tissue, which is prepared by dissolving base cloth in hot water, the base cloth comprises a first composite material and a second composite material, the first composite material comprises first polypropylene, modified cellulose nanocrystal and N, N-diallylmelamine grafted second polypropylene, the second composite material comprises polyvinyl alcohol, and the modified cellulose nanocrystal and the N, N-diallylmelamine grafted second polypropylene are mixed to form the hydrophilic composite non-woven fabric. The first composite material and the second composite material are spun by a two-component melt spinning machine to form the base cloth. Second polypropylene is grafted through N, N-diallyl melamine, so that the polarity of the second polypropylene is improved, the surface of the polypropylene becomes hydrophilic, wettable and adhesive, and the compatibility of the polypropylene and a polar material is improved; the hydrophilicity of the polypropylene fiber is further improved by combining with the modified cellulose nanocrystals, and the skin-friendly property and the degradability of the non-woven fabric are improved.

Description

Technical Field

[0001] This invention relates to the field of cleaning products technology, specifically to a hydrophilic composite nonwoven fabric for wet wipes, cleaning wet wipes, and a method for preparing wet wipes. Background Technology

[0002] Polypropylene nonwoven fabric is currently the most widely used and technologically mature substrate in the wet wipes industry. Virgin polypropylene fibers are strongly hydrophobic and cannot quickly absorb and retain moisture, so they must undergo finishing processes (such as hydrophilic coating or corona treatment) before they can be used in wet wipes. Furthermore, polypropylene is difficult to degrade in the natural environment, and discarded wet wipes, when landfilled as mixed waste or flowing into the environment, will cause "white pollution."

[0003] Therefore, it is necessary to modify polypropylene nonwoven fabrics to move towards the forefront of green properties. Summary of the Invention

[0004] One of the objectives of this invention is to overcome the deficiencies in the prior art and provide a hydrophilic composite nonwoven fabric for wet wipes. By grafting a second polypropylene with N,N-diallyl melamine, its polarity is improved, making the polypropylene surface hydrophilic, wettable, and adhesive, thus improving the compatibility of polypropylene with polar materials. Combined with modified cellulose nanocrystals, the hydrophilicity of polypropylene fibers is further improved, and the skin-friendliness and degradability of the nonwoven fabric are also improved.

[0005] To achieve the above-mentioned process effects, the technical solution of the present invention is as follows: a hydrophilic composite nonwoven fabric for wet wipes, which is made by dissolving a base fabric in hot water. The base fabric includes a first composite material and a second composite material. The first composite material includes a first polypropylene, modified cellulose nanocrystals and N,N-diallyl melamine grafted onto a second polypropylene. The second composite material includes polyvinyl alcohol. The first composite material and the second composite material are spun into a base fabric by a two-component melt spinning machine.

[0006] The preferred technical solution is that the feeding ratio of the first composite material and the second composite material is 1:(0.5~1).

[0007] The preferred technical solution is that, by mass parts, the first composite material comprises 100 parts of first polypropylene, 1-7 parts of modified cellulose nanocrystals, and 10-20 parts of N,N-diallyl melamine-grafted second polypropylene.

[0008] The preferred technical solution is that the modified cellulose nanocrystals are obtained by hydrolyzing microcrystalline cellulose using hydrochloric acid.

[0009] The preferred technical solution is that the N,N-diallyl melamine-grafted second polypropylene is obtained by melt co-extrusion of the second polypropylene, N,N-diallyl melamine, dicumyl peroxide and antioxidant.

[0010] The preferred technical solution is that the mass ratio of the second polypropylene, N,N-diallyl melamine, dicumyl peroxide and antioxidant is 100:(5~8):(0.35~0.42):(0.08~0.12).

[0011] The preferred technical solution is that the melt index of the first polypropylene is 25~30 g / 10min, the melt index of the second polypropylene is 40~50 g / 10min, and the melt index of the N,N-diallylmelamine-grafted second polypropylene is 33~39 g / 10min.

[0012] The second objective of this invention is to overcome the deficiencies in the existing technology and provide a cleaning wipe, comprising the aforementioned hydrophilic composite nonwoven fabric for wipes and a body lotion. By weight, the body lotion comprises 0.5%~2% isostearyl glycerin, 0.5%~2.5% polypropylene glycol-17, 0.5%~4% polyethylene glycol-8, 0.5%~2% PEG-60 hydrogenated castor oil, and lauryl ether-6... The cleaning wipes contain 0.5%~2% disodium ethylenediaminetetraacetate (EDTA), 0.05%~0.15% ethylenediaminetetraacetate (EDTA), 0.1%~0.6% phenoxyethanol, 0.01%~0.3% methyl paraben, 0.01%~0.3% ethyl paraben, 0.05%~0.5% tromethamine, 0.1%~0.2% fragrance, 1%~5% dipropylene glycol, 1%~5% propylene glycol, and the balance being water; the mass ratio of the emulsion to the hydrophilic composite nonwoven fabric in the cleaning wipes is (3~8):1.

[0013] The third objective of this invention is to overcome the deficiencies in the prior art and provide a method for preparing a hydrophilic composite nonwoven fabric for wet wipes, comprising the following steps: S1: A modified cellulose nanocrystal and N,N-diallyl melamine-grafted second polypropylene; S2: First polypropylene, N,N-diallylmelamine-grafted second polypropylene and modified cellulose nanocrystals are sequentially mixed to form a first composite material, and fed into one screw extrusion of a two-component melt spinning machine. S3: The polyvinyl alcohol is fed into the other screw of the two-component melt spinning machine for extrusion; S4: After the first composite material and polyvinyl alcohol are extruded, they are spun, spun into fibers, hot rolled, compressed, stretched and cooled to obtain the base fabric; S5: Dissolve the polyvinyl alcohol in hot water using the base fabric; In step S4, spinning is performed using an island-to-island spinning assembly, and the cross-section of the resulting fiber is formed by the first composite material embedded in the polyvinyl alcohol material.

[0014] The preferred technical solution is as follows: in step S2, the extrusion temperature of one screw of the bicomponent melt spinning machine is 225~235℃, and the temperature of the die is 225~235℃; in step S3, the extrusion temperature of the other screw of the bicomponent melt spinning machine is 220~230℃, and the temperature of the die is 225~235℃; in step S5, the temperature of the hot water is 80~88℃.

[0015] The advantages and beneficial effects of this invention are as follows: By grafting N,N-diallyl melamine onto the second polypropylene, its polarity is increased, making the polypropylene surface hydrophilic, wettable, and adhesive, thus improving the compatibility of polypropylene with polar materials. Combined with modified cellulose nanocrystals, the hydrophilicity of polypropylene fibers is further improved, replacing traditional hydrophilic finishing agents. The introduction of bio-based materials also enhances the overall biocompatibility of the material, as well as improves the skin-friendliness and degradability of the nonwoven fabric. Detailed Implementation

[0016] The specific embodiments of the present invention will be further described below with reference to examples. These examples are only used to more clearly illustrate the technical solutions of the present invention and should not be construed as limiting the scope of protection of the present invention.

[0017] Hydrophilic composite nonwoven fabric for wet wipes The base fabric is made by hot water dissolution of the base fabric. The base fabric includes a first composite material and a second composite material. By mass parts, the first composite material includes 100 parts of first polypropylene, 1-7 parts of modified cellulose nanocrystals, and 10-20 parts of N,N-diallyl melamine-grafted second polypropylene. The second composite material includes polyvinyl alcohol. The feed ratio of the first composite material and the second composite material is 1:(0.5-1). The base fabric is formed by spinning through a two-component melt spinning machine.

[0018] By grafting N,N-diallyl melamine onto the second polypropylene, its polarity is increased, making the polypropylene surface hydrophilic, wettable, and adhesive, thus improving the compatibility of polypropylene with polar materials. Combining this with modified cellulose nanocrystals further enhances the hydrophilicity of the polypropylene fibers, replacing traditional hydrophilic finishing agents. Furthermore, the introduction of bio-based materials improves the overall biocompatibility of the material, as well as the skin-friendliness and biodegradability of the nonwoven fabric.

[0019] N,N-diallyl melamine-grafted second polypropylene was prepared by melt co-extrusion of second polypropylene, N,N-diallyl melamine, dicumyl peroxide, and an antioxidant in a mass ratio of 100:(5~8):(0.35~0.42):(0.08~0.12). The antioxidant was a blend of Irganox 1010 and Irgafos 168 in a mass ratio of 1:1.5, which reduced the degradation of polypropylene during the extrusion process in the grafting reaction, improved its thermal stability, and effectively reduced the melt flowability of the grafted polypropylene. The co-extrusion temperature was 170~175℃, and the die temperature was 180℃.

[0020] Modified cellulose nanocrystals were prepared by hydrolyzing microcrystalline cellulose (Shanghai Guchen Biotechnology Co., Ltd.) using hydrochloric acid. Specifically, 10g of microcrystalline cellulose was added to a 10mol / L hydrochloric acid solution to prepare a 5% (w / w) dispersion, which was then heated and hydrolyzed at 90-100℃ for 3.5h. The reaction was terminated with deionized water, and the nanocrystals were centrifuged and dried before use. The modified cellulose nanocrystals prepared by the hydrochloric acid method have fewer amorphous regions and unchanged crystalline regions, resulting in higher crystallinity. Therefore, the hydrochloric acid-modified cellulose nanocrystals exhibit high thermal stability, with the first thermal decomposition temperature during thermal degradation exceeding 360℃. Thus, hydrochloric acid-modified cellulose nanocrystals can be blended with polypropylene for modification, effectively solving the problem of thermal degradation and discoloration of cellulose nanocrystals at the melt processing temperature of polypropylene. In the preparation of modified cellulose nanocrystals, multiple washing is not required after hydrolysis, and a small amount of chloride ions are retained. When compounded with N,N-diallyl melamine grafted onto second polypropylene, the N,N-diallyl melamine molecule contains a planar triazine structure and an amino group, among which -NH2 is a highly active reaction site. The combination of chloride ions and amino groups can improve the antibacterial properties of the first composite material.

[0021] Preparation of the base fabric: First polypropylene, N,N-diallyl melamine-grafted second polypropylene, and modified cellulose nanocrystals are sequentially mixed to form a first composite material, which is then fed into one screw extruder of a two-component melt spinning machine. Polyvinyl alcohol is fed into the other screw extruder of the two-component melt spinning machine. The extrusion temperature of one screw of the two-component melt spinning machine is 225~235℃, and the die temperature is also 225~235℃. The extrusion temperature of the other screw of the two-component melt spinning machine is 220~230℃, and the die temperature is also 225~235℃. After extrusion, the first composite material and polyvinyl alcohol undergo spinning, spinning, hot rolling, compression, stretching, and cooling. The orifice diameter of the spinneret is 0.5 mm, and the stretching pressure is 12 psi. The mixing sequence of the first composite material is beneficial to improving the dispersibility of each substance. The base fabric is hydrolyzed using hot water at 80~88℃.

[0022] Because the first composite material is modified by grafting N,N-diallyl melamine onto the second polypropylene and modifying cellulose nanocrystals, and then contacts and composites with polyvinyl alcohol melt under high temperature and high pressure conditions, cross-linking occurs between molecules at the interface of the two components. That is, some polyvinyl alcohol molecular chains at the interface diffuse into the first composite material and form cross-links. During hot hydrolysis, the undiffused and uncross-linked molecules are removed, and the retained polyvinyl alcohol molecules further improve the hydrophilicity of the composite nonwoven fabric. Furthermore, the gaps created between the fibers of the base fabric through hydrolysis expose the hydrophilic and antibacterial groups, thereby endowing the composite nonwoven fabric with excellent hydrophilicity and antibacterial properties. Polyvinyl alcohol can be recycled.

[0023] In terms of raw material selection, generally, the lower the melt index of the polymer, the higher its corresponding molecular weight, the longer the macromolecular chain segments, and the more intermolecular entanglement, which macroscopically manifests as greater viscosity. The melt index of the first polypropylene is 25-30 g / 10min, forming single fibers composed of multiple fine filaments bundled together, improving the strength of the first composite material. The melt index of the second polypropylene is 40-50 g / 10min, which facilitates sufficient contact with N,N-diallyl melamine during grafting. Due to the steric hindrance and polar effect of the triazine structure and amino groups on the N,N-diallyl melamine-grafted second polypropylene, the flowability of the N,N-diallyl melamine-grafted second polypropylene decreases. Therefore, the melt index of the N,N-diallyl melamine-grafted second polypropylene is 33-39 g / 10min. The N,N-diallyl melamine-grafted second polypropylene fibers coat the surface of the first polypropylene fibers, improving the mechanical strength and hydrophilicity of the composite nonwoven fabric.

[0024] Cleaning wipes The cleaning wipes include the aforementioned hydrophilic composite nonwoven fabric for wipes and a body lotion. By mass percentage, the body lotion includes 0.5%~2% isostearyl glycerin, 0.5%~2.5% polypropylene glycol-17, 0.5%~4% polyethylene glycol-8, 0.5%~2% hydrogenated castor oil PEG-60, 0.5%~2% lauryl ether-6, 0.05%~0.15% disodium EDTA, 0.1%~0.6% phenoxyethanol, 0.01%~0.3% methyl paraben, 0.01%~0.3% ethyl paraben, 0.05%~0.5% tromethamine, 0.1%~0.2% fragrance, 1%~5% dipropylene glycol, 1%~5% propylene glycol, and the balance being water. The mass ratio of the body lotion to the hydrophilic composite nonwoven fabric in the cleaning wipes is (3~8):1.

[0025] Isostearyl glycerin is a mild skin conditioning agent, belonging to the oil-based category. It forms a thin, breathable protective film on the skin surface, reducing moisture loss and increasing the smoothness of the product (making lotions spread more delicately). Its light and refreshing texture makes it suitable for various skin types. Polypropylene glycol-17 primarily functions as an emulsifier and solubilizer, adjusting the oil-water ratio of the product, improving lotion stability, and also helping to dissolve some oil-soluble components, resulting in a more uniform texture. Polyethylene glycol-8 is an excellent solvent and moisturizer, enhancing the moisture content of the stratum corneum, and its lightweight texture prevents the product from feeling sticky. The solubilizer is PEG-60 hydrogenated castor oil, used to solubilize oil-soluble components such as silicone oil and fragrances, ensuring the system is transparent or homogeneous. Lauryl ether-6 is a nonionic surfactant with emulsifying, cleaning, and solubilizing properties. In cleansing products (such as shower gel), it absorbs oil and dirt from the skin's surface, helping to rinse thoroughly. In emulsions, it acts as an emulsifier, allowing the oil and water phases to form a stable emulsion and preventing product separation. Disodium ethylenediaminetetraacetate (EDTA-2Na) is a chelating agent whose core function is to stabilize the product. Trace amounts of metal ions (such as calcium and iron) may be present in water or raw materials. These ions can accelerate component oxidation, leading to product discoloration or deterioration. EDTA-2Na can bind with metal ions to form a stable structure, preventing them from damaging the product and extending shelf life. Phenoxyethanol is a commonly used preservative and also has some moisturizing properties. It inhibits the growth of bacteria, yeast, and other microorganisms and has a high safety profile. Methylparaben and ethylparaben are both paraben preservatives with a broad antibacterial spectrum (inhibiting various bacteria and fungi). Methylparaben has better water solubility and is often used in water-based products; ethylparaben has slightly stronger lipid solubility. The two are often used together to enhance the preservative effect. Tromethamine is a commonly used pH adjuster, weakly alkaline, which can neutralize acidic components in cosmetics, adjusting the product's pH to a range close to the skin's pH, reducing skin irritation, and stabilizing emulsion systems. Dipropylene glycol (DPG) has a dual function as both a solvent and a humectant. As a humectant, it has mild hygroscopic properties, forming a thin moisturizing film on the skin surface to reduce moisture loss, and is less irritating than traditional humectants. As a solvent, it can dissolve fragrances, etc. Propylene glycol (PG) functions similarly to dipropylene glycol, being a classic humectant and solvent. It can absorb moisture from the air and adhere to the skin surface to relieve dryness; it can also improve the spreadability of products. Water is used as a base to adjust the texture of the product and its fluidity allows the ingredients to be evenly distributed while providing basic hydration to the skin.

[0026] Example 1

[0027] The wet wipes are made from a hydrophilic composite nonwoven fabric produced by dissolving a base fabric in hot water. The base fabric comprises a first composite material and a second composite material with a feed ratio of 1:0.67, spun using a two-component melt spinning machine. The first composite material, by weight, comprises 100 parts of a first polypropylene (Korean Hyosung J742), 5 parts of modified cellulose nanocrystals, and 16 parts of an N,N-diallyl melamine-grafted second polypropylene (Shanghai SECCO S2045). The second composite material comprises polyvinyl alcohol.

[0028] The preparation method of hydrophilic composite nonwoven fabric for wet wipes includes the following steps: S1: A modified cellulose nanocrystal and N,N-diallyl melamine-grafted second polypropylene; Modified cellulose nanocrystals: 10g of microcrystalline cellulose (Shanghai Guchen Biotechnology Co., Ltd.) was added to a 10mol / L hydrochloric acid solution to prepare a dispersion with a mass fraction of 5%. The dispersion was then heated and hydrolyzed at 98℃ for 3.5h. The reaction was terminated with deionized water. After centrifugation and drying, the nanocrystals were ready for use.

[0029] N,N-diallyl melamine-grafted second polypropylene was prepared by melt co-extrusion of second polypropylene, N,N-diallyl melamine, dicumyl peroxide and antioxidant in a mass ratio of 100:6.5:0.38:0.09. The antioxidant was a compound of antioxidants Irganox1010 and Irgafos168 in a mass ratio of 1:1.5. The co-extrusion temperature was 175℃ and the die temperature was 180℃.

[0030] S2: The first polypropylene, N,N-diallylmelamine-grafted second polypropylene and modified cellulose nanocrystals are mixed sequentially to form the first composite material, and fed into one screw of a two-component melt spinning machine for extrusion. The extrusion temperature of the first screw of the two-component melt spinning machine is 230°C and the temperature of the die is 235°C. S3: Polyvinyl alcohol is fed into the other screw of the two-component melt spinning machine for extrusion. The extrusion temperature of the other screw of the two-component melt spinning machine is 225°C, and the temperature of the die is 230°C.

[0031] S4: After the first composite material and polyvinyl alcohol are extruded, the base fabric is obtained through spinning, spun yarn, hot rolling, compression, stretching and cooling. The spun yarn has an orifice diameter of 0.5 mm and a stretching pressure of 12 psi.

[0032] S5: Dissolve the polyvinyl alcohol in hot water at a temperature of 86°C.

[0033] The cleaning wipes comprise the aforementioned hydrophilic composite nonwoven fabric for wipes and a body lotion. By weight, the body lotion comprises 1.4% isostearyl glycerin, 1.8% polypropylene glycol-17, 2.5% polyethylene glycol-8, 1.2% hydrogenated castor oil PEG-60, 1.2% lauryl ether-6, 0.1% disodium EDTA, 0.3% phenoxyethanol, 0.15% methyl paraben, 0.15% ethyl paraben, 0.22% tromethamine, 0.12% fragrance, 3% dipropylene glycol, 2.5% propylene glycol, and the balance being water.

[0034] The mass ratio of body emulsion to hydrophilic composite nonwoven fabric in the cleaning wipes is 4:1.

[0035] Example 2

[0036] Example 2 is based on Example 1, except that the base fabric includes a first composite material and a second composite material with a feed ratio of 1:1.5, which are formed by spinning through a two-component melt spinning machine.

[0037] Example 3

[0038] Example 3 is based on Example 1, except that the base fabric 2 includes a first composite material and a second composite material with a feed ratio of 1:0.5, which are formed by spinning through a two-component melt spinning machine.

[0039] Example 4

[0040] Example 4 is based on Example 1, except that, by mass parts, the first composite material includes 100 parts of first polypropylene, 1 part of modified cellulose nanocrystals, and 16 parts of N,N-diallyl melamine-grafted second polypropylene.

[0041] Example 5

[0042] Example 5 is based on Example 1, except that, by mass parts, the first composite material includes 100 parts of first polypropylene, 7 parts of modified cellulose nanocrystals, and 16 parts of N,N-diallyl melamine-grafted second polypropylene.

[0043] Example 6

[0044] Example 6 is based on Example 1, except that, by mass parts, the first composite material includes 100 parts of first polypropylene, 5 parts of modified cellulose nanocrystals, and 20 parts of N,N-diallyl melamine-grafted second polypropylene.

[0045] Example 7

[0046] Example 7 is based on Example 1, except that, by mass parts, the first composite material includes 100 parts of first polypropylene, 5 parts of modified cellulose nanocrystals, and 5 parts of N,N-diallyl melamine-grafted second polypropylene.

[0047] Example 8

[0048] Example 8 is based on Example 1, except that the modified cellulose nanocrystals are prepared by hydrolyzing microcrystalline cellulose with sulfuric acid. Specifically, 10g of microcrystalline cellulose is added to a 60% sulfuric acid solution to prepare a 5% dispersion, and then heated and hydrolyzed at 40°C for 2 hours. The reaction is terminated with deionized water, and the solution is washed, centrifuged, and dried before use.

[0049] Comparative Example 1 Comparative Example 1 is based on Example 1, except that the first composite material comprises a first polypropylene and an N,N-diallyl melamine-grafted second polypropylene, but does not include modified cellulose nanocrystals.

[0050] Comparative Example 2 Comparative Example 2 is based on Example 1, except that the first composite material includes a first polypropylene and does not include modified cellulose nanocrystals and N,N-diallyl melamine-grafted second polypropylene.

[0051] Performance testing of hydrophilic composite nonwoven fabric samples prepared in the examples and comparative examples: 1. Tensile strength and elongation at break: determined according to standard ISO 9073-3:2023.

[0052] 2. Water contact angle: Shanghai Fangrui JCY-3 contact angle tester, record the initial contact angle at 0.1s.

[0053] 3. Antibacterial properties: According to standard GB / T 20944.3 Evaluation of antibacterial properties of textiles Part 3: Vibration method.

[0054] The performance test results of the examples and comparative examples are as follows:

[0055] An antibacterial rate of 70% or higher is required to demonstrate antibacterial properties.

[0056] Since the hydrophilic composite nonwoven fabrics in the examples and comparative examples were modified with polyvinyl alcohol, after more than 2 minutes of water slowly wetting, the water contact angle gradually became 0°.

[0057] The hydrophilic composite nonwoven fabrics of Examples 1-8 and Comparative Example 1 have a water absorption rate of over 90%, while the hydrophilic composite nonwoven fabric of Comparative Example 2 has a lower water absorption rate because it does not contain N,N-diallyl melamine grafted onto the second polypropylene and the polyvinyl alcohol only extends and adheres to the polypropylene surface.

[0058] Compared to Example 1, Example 2 shows that the feeding ratio of the second composite material is too large, which easily leads to a decrease in the fiber fineness of the resulting hydrophilic composite nonwoven fabric and a decline in its mechanical properties.

[0059] Compared to Example 1, Example 3 shows that the feed ratio of the second composite material is reduced, which has a negative impact on the water contact angle.

[0060] Compared to Example 1, the reduced amount of modified cellulose nanocrystals in Examples 4 and 5 negatively impacted tensile strength, and the decrease in active chloride ions also negatively affected antibacterial properties. Increasing the amount of modified cellulose nanocrystals improved tensile strength, but excessive amounts could lead to agglomeration.

[0061] Compared to Example 1, Example 7 showed that the amount of N,N-diallylmelamine-grafted second polypropylene added was too small, which negatively affected the compatibility of the modified cellulose nanocrystals and polypropylene, thus affecting the mechanical properties of the composite nonwoven fabric. The reduced number of active amino groups also negatively impacted both hydrophilicity and antibacterial properties.

[0062] Compared to Example 1, Example 8 showed that the modified cellulose nanocrystals obtained by sulfuric acid hydrolysis of microcrystalline cellulose had better dispersibility, but poor thermal stability, leading to a decrease in the mechanical properties of the resulting hydrophilic composite nonwoven fabric. Its antibacterial properties were also poor.

[0063] Compared to Example 1, Comparative Examples 1 and 2 show that the first composite material, which is a combination of first polypropylene with modified cellulose nanocrystals and N,N-diallyl melamine grafted onto second polypropylene, and then combined with polyvinyl alcohol, produces the hydrophilic composite nonwoven fabric with the best performance.

[0064] Performance testing of cleaning wipes samples prepared in the examples and comparative examples: Sensory evaluation method: The cleaning wipes prepared in the examples and comparative examples were distributed to 30 testers for comparison. Testers used the samples according to the same method and rated them based on their own feelings. Cleaning ability refers to the wipes' ability to remove dirt; gentleness refers to whether the wipes caused irritation, such as redness or burning sensation on the skin; skin-friendliness refers to whether the wipes felt smooth during wiping, without any roughness or scratching. A 10-point scale was used, with 1 being the worst and 10 being the best. The average of the testers' scores was calculated; a higher score indicated better performance.

[0065] The performance test results of the examples and comparative examples are as follows:

[0066] Compared to Example 1, Example 7 shows that the amount of N,N-diallylmelamine-grafted second polypropylene added is too small, which has a negative impact on the compatibility of modified cellulose nanocrystals and polypropylene, resulting in poor skin-friendliness of the composite nonwoven fabric.

[0067] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A hydrophilic composite nonwoven fabric for wet wipes, characterized in that, The base fabric is made by hot water dissolution of a base fabric, which includes a first composite material and a second composite material. The first composite material includes a first polypropylene, modified cellulose nanocrystals, and N,N-diallyl melamine-grafted second polypropylene. The second composite material includes polyvinyl alcohol. The first composite material and the second composite material are spun into a base fabric by a two-component melt spinning machine.

2. The hydrophilic composite nonwoven fabric for wet wipes according to claim 1, characterized in that, The feeding ratio of the first composite material and the second composite material is 1:(0.5~1).

3. The hydrophilic composite nonwoven fabric for wet wipes according to claim 1 or 2, characterized in that, By weight, the first composite material comprises 100 parts of first polypropylene, 1-7 parts of modified cellulose nanocrystals, and 10-20 parts of N,N-diallyl melamine-grafted second polypropylene.

4. The hydrophilic composite nonwoven fabric for wet wipes according to claim 3, characterized in that, The modified cellulose nanocrystals were obtained by hydrolyzing microcrystalline cellulose using hydrochloric acid.

5. The hydrophilic composite nonwoven fabric for wet wipes according to claim 3, characterized in that, The N,N-diallyl melamine-grafted second polypropylene is obtained by melt co-extrusion of the second polypropylene, N,N-diallyl melamine, dicumyl peroxide and antioxidant.

6. The hydrophilic composite nonwoven fabric for wet wipes according to claim 5, characterized in that, The mass ratio of the second polypropylene, N,N-diallyl melamine, dicumyl peroxide and antioxidant is 100:(5~8):(0.35~0.42):(0.08~0.12).

7. The hydrophilic composite nonwoven fabric for wet wipes according to claim 1 or 6, characterized in that, The melt index of the first polypropylene is 25~30 g / 10min, the melt index of the second polypropylene is 40~50 g / 10min, and the melt index of the N,N-diallylmelamine-grafted second polypropylene is 33~39 g / 10min.

8. A cleaning wipe, characterized in that, The wet wipes include the hydrophilic composite nonwoven fabric and body lotion as described in any one of claims 1 to 7. The body lotion, by mass percentage, comprises 0.5% to 2% isostearyl glycerin, 0.5% to 2.5% polypropylene glycol-17, 0.5% to 4% polyethylene glycol-8, 0.5% to 2% hydrogenated castor oil (PEG-60), 0.5% to 2% lauryl ether-6, 0.05% to 0.15% disodium EDTA, 0.1% to 0.6% phenoxyethanol, 0.01% to 0.3% methyl paraben, 0.01% to 0.3% ethyl paraben, 0.05% to 0.5% tromethamine, and 0.5% fragrance. 1%~0.2%, dipropylene glycol 1%~5%, propylene glycol 1%~5% and the balance water; the mass ratio of the body emulsion and the hydrophilic composite nonwoven fabric in the cleaning wipes is (3~8):

1.

9. A method for preparing a hydrophilic composite nonwoven fabric for wet wipes, characterized in that, Includes the following steps: S1: A modified cellulose nanocrystal and N,N-diallyl melamine-grafted second polypropylene; S2: First polypropylene, N,N-diallylmelamine-grafted second polypropylene and modified cellulose nanocrystals are sequentially mixed to form a first composite material, and fed into one screw extrusion of a two-component melt spinning machine. S3: The polyvinyl alcohol is fed into the other screw of the two-component melt spinning machine for extrusion; S4: After the first composite material and polyvinyl alcohol are extruded, they are spun, spun into fibers, hot rolled, compressed, stretched and cooled to obtain the base fabric; S5: Dissolve the polyvinyl alcohol in hot water using the base fabric; In step S4, spinning is performed using an island-to-island spinning assembly, and the cross-section of the resulting fiber is formed by the first composite material embedded in the polyvinyl alcohol material.

10. The method for preparing the hydrophilic composite nonwoven fabric for wet wipes according to claim 9, characterized in that, In step S2, the extrusion temperature of one screw of the bicomponent melt spinning machine is 225~235℃, and the temperature of the die is 225~235℃; in step S3, the extrusion temperature of the other screw of the bicomponent melt spinning machine is 220~230℃, and the temperature of the die is 225~235℃; in step S5, the temperature of the hot water is 80~88℃.

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