A wet / dry composite gradient formed hydroentangled wiping cloth and a method of making the same

Abstract

The application discloses a wet / dry composite gradient forming water-jet wiping cloth, which comprises an integrated structure formed by blending short-cut cellulose staple fibers and PET short fibers and then reinforcing by gradient water-jet. 2 The mass mixing ratio of the short-cut cellulose staple fibers and the PET short fibers is 30:70 to 60:40. 2 The fiber density of the surface layer is 18-22 roots / mm The fiber density ratio of the surface layer to the core layer is (3.0-3.6):1. The surface layer is a region within the range of 1 / 10 thickness from the surface of the wiping cloth, and the core layer is a region within the range of 1 / 3 thickness in the thickness direction of the wiping cloth. The application cooperates the differential fiber size design and the three-section variable-pressure water-jet process to spontaneously form the fiber density gradient structure in the thickness direction on the basis of the dry web forming, without the need of pulp fibers, the flow head water medium forming system, the singeing process and the ultra-fine water jet modification process, so that the low-dropping, high-flatness and excellent liquid storage performance can be realized at the same time, and the high-clean and precise wiping scene is adapted.

Description

Technical Field

[0001] This invention belongs to the field of nonwoven fabric technology, specifically relating to a spunlace wiping cloth and its preparation method. Background Technology

[0002] In high-cleanliness environments such as those involving semiconductor wafers, optical lenses, and precision instruments, the amount of lint shed from wiping cloths is one of the most critical quality indicators. Lint not only directly contaminates the surface being cleaned but can also cause more serious secondary pollution.

[0003] In existing technologies, the following solutions are mainly used to reduce the amount of lint shed from wiping cloths: Option 1: Pulp fiber headstock forming + singeing finishing. CN111876911A discloses a low-shedding pulp composite jacquard nonwoven fabric and its manufacturing method. This option uses wood pulp fiber (pulp fiber) to form in an aqueous headstock system, and finishes the fabric surface through ultrafine water jet penetration technology (10-60 bar) or singeing process (copper roller surface temperature 150-280℃), achieving a shedding performance of less than 2g / m². 2 The drawbacks of this approach are: it requires a dedicated pulper water-based forming system, resulting in a large investment in equipment; the dispersion of pulp fibers in water requires an ultrasonic dispersion device (frequency 20kHz-40kHz), which consumes a lot of energy; and the singeing process poses safety risks.

[0004] Option 2: Pulp fiber laminated structure. CN213596554U discloses a low-shedding pulp composite jacquard nonwoven fabric, which consists of a pulp fiber layer and fiber layer A forming a double-layer structure, with a shedding performance of less than 2g / m. 2 The drawback of this approach is that it still relies on the pulp fiber layer, and the double-layer structure requires special airflow and water flow to distribute the pattern, making process control complex.

[0005] Option 3: Differentially entangled spunlace fabric. MX256921B discloses a differentially entangled nonwoven fabric, which forms a highly entangled outer surface and a slightly entangled inner core layer on the fabric surface by controlling the hydroentangling energy. However, this option is only described qualitatively and does not provide quantitative density gradient parameters or a reproducible process window.

[0006] In summary, the achievement of low-shedding hydroentangled wiping cloths in existing technologies generally relies on complex processes such as pulp fibers, a pulper aqueous media forming system, and singeing / ultrafine water jet modification. A long-standing and prevalent technological bias exists in this field: the belief that achieving 1 g / m³ requires... 2 The following ultra-low shedding levels require a wet pulp forming process combined with surface finishing. Dry-laid spunlace nonwoven fabrics have weak fiber cohesion and more surface loose fibers, resulting in shedding levels generally exceeding 2 g / m². 2This method cannot meet the requirements of high-cleanliness applications such as semiconductors and optics. Therefore, those skilled in the art would not attempt to achieve ultra-low chip shedding performance by matching fiber-scale design with hydroentanglement process under the dry web formation route. Summary of the Invention

[0007] This invention addresses the technical shortcomings of existing high-cleanliness wiping cloths, and aims to solve the following technical problems: 1. Traditional wet-laid spunlace wiping cloths rely on wood pulp fibers and a pulper water-medium forming system. The pulp fibers are extremely short and mainly bonded by hydrogen bonds, resulting in low fiber bonding strength. During wiping, microfibers and debris are easily shed, failing to meet the low-shedding requirements of clean environments such as semiconductor wafers, optical lenses, and precision instruments; 2. Existing gradient structure wiping cloths are mostly achieved through multi-layer composite web laying, singeing, or ultra-fine water jet surface modification. These processes are cumbersome and require significant equipment investment. Singeing can easily cause thermal damage to fibers and produce charred debris, while ultra-fine water jet technology has extremely high energy consumption, resulting in high costs for large-scale production; 3. Conventional dry-laid spunlace nonwovens struggle to balance surface density and internal liquid retention. Increasing the overall spunlace pressure leads to stiffness and reduced liquid retention, while decreasing the spunlace pressure results in loose surface fibers and a high risk of shedding. The core performance cannot be balanced.

[0008] To address the shortcomings of the existing technologies, this invention provides a wet / dry composite gradient-formed spunlace wiping cloth and its preparation method. Through differentiated fiber scale design and three-stage variable pressure spunlace process, a fiber density gradient structure in the thickness direction is spontaneously formed on the basis of dry web formation. It can achieve low lint shedding, high flatness and excellent liquid storage performance simultaneously without pulp fiber, pulper water medium forming system, singeing process and ultrafine water jet modification process, making it suitable for high-cleanliness precision wiping scenarios.

[0009] To achieve the above objectives, the following technical solution is adopted: A wet / dry composite gradient-molded spunlace wiping cloth includes an integral structure formed by blending short-cut cellulose short fibers and PET short fibers and then reinforcing them with gradient hydroentangling; the mass mixing ratio of the short-cut cellulose short fibers and PET short fibers is 30:70 to 60:40. The wiping cloth has a fiber density gradient distribution in the thickness direction: the surface fiber density is 18-22 fibers / mm. 2 The core fiber density is 5-7 fibers / mm. 2 The fiber density ratio of the surface layer to the core layer is (3.0~3.6):1; the surface layer is the area within 1 / 10 of the thickness of the wiping cloth surface, and the core layer is the area within 1 / 3 of the thickness of the wiping cloth in the middle direction of the thickness. The fiber density is obtained by observing and counting the number of fibers per unit area using a cross-sectional scanning electron microscope.

[0010] According to the above scheme, the short-cut cellulose fibers are selected from one or two of lyocell short fibers and viscose short fibers, with a cut length of 3 to 8 mm and a fineness of 1.0 to 2.0 denier.

[0011] According to the above scheme, the cut length of the PET short fiber is 38-51 mm, and the fineness is 1.0-2.5 denier.

[0012] According to the above scheme, the total surface density of the wiping cloth is 40-80 g / m². 2 The total thickness is 0.30-0.60mm.

[0013] According to the above scheme, the amount of lint shed by the wiping cloth is ≤0.8g / m². 2 The wiping cloth does not contain pulp fibers.

[0014] This invention also provides a method for preparing the above-mentioned wet / dry composite gradient-formed spunlace wiping cloth, comprising the following steps: S1. Fiber blending: Opening and blending short-cut cellulose fibers with PET short fibers; S2. Dry web formation: The mixed fibers are formed into a uniform fiber web through carding or air-flow web formation processes. S3. Gradient hydroentangling reinforcement: The fiber web is reinforced using a three-stage variable pressure hydroentangling process; the first stage applies 100±5 bar high-pressure hydroentangling from the front of the fiber web; the second stage applies 100±5 bar high-pressure hydroentangling from the back of the fiber web; and the third stage applies 40±5 bar low-pressure hydroentangling from both sides of the fiber web simultaneously. S4. Dehydration and Drying: The hydroentangled nonwoven fabric is dehydrated and dried. The entire preparation process does not use a headstock water-medium forming system, nor does it employ singeing or ultrafine water jet finishing processes.

[0015] According to the above scheme, the short-cut cellulose fibers mentioned in step S1 are opened before use, and the opening machine beater speed is 800-1200 rpm.

[0016] According to the above scheme, in step S2, the main cylinder speed of the carding machine in the carding web forming process is 800-1200 rpm, and the doffer speed is 30-60 m / min.

[0017] According to the above scheme, in step S3, the number of water jets in the first and second sections is 3-4 each, and the diameter of the water jets is 0.12-0.15mm; the number of water jets on both sides of the third section is 2-3 each; and the conveying speed is 18-22m / min.

[0018] According to the above scheme, the drying temperature in step S4 is 120-140℃.

[0019] This invention also provides the application of the above-mentioned wet / dry composite gradient-formed spunlace wiping cloth in the fields of semiconductor wafer cleaning, optical lens wiping, and precision instrument cleaning.

[0020] The wet / dry composite gradient forming process of this invention uses a dry web-forming process to prepare the fiber web and combines it with a wet hydroentangling process for reinforcement. Through the fiber-scale differential migration effect and the three-stage variable pressure hydroentangling consolidation mechanism, a fiber density gradient in the thickness direction is spontaneously formed within the integrated fiber web, solving the problem of lint shedding and performance balance from the structural root. The specific technical principle is as follows: The invention utilizes a gradient self-forming mechanism based on fiber-scale differences. It blends short-cut cellulose fibers with significantly different lengths with long PET fibers, leveraging the difference in migration ability between the two types of fibers under high-pressure water flow to achieve spontaneous stratification: Short-cut cellulose fibers (3-8 mm in length, one or both of lyocell and viscose) are short and have low rigidity, exhibiting high mobility under water jet impact. They easily move towards the surface of the fiber web and tightly entangle, forming a dense and flat wiping surface, structurally reducing the risk of surface fiber shedding. PET short fibers (38-51 mm in length) are long and have strong cohesion, remaining as skeleton fibers in the core layer of the fiber web, forming a three-dimensional, loose support structure that is not easily displaced by water flow impact, ensuring a low-density, loose liquid storage space in the core layer. This spontaneous stratification effect, with short fibers enriching the surface and long fibers remaining in the core layer, naturally creates a fiber density gradient distribution along the thickness direction of the fiber web: a dense surface and a loose core. This achieves an integrated gradient structure without the need for multi-layer web laying or composite processes.

[0021] The invention employs a three-stage variable-pressure hydroentangling process with gradient consolidation and low-debris control. This process combines "positive and negative high-pressure pre-consolidation + double-sided low-pressure finishing" to precisely control the degree of fiber entanglement in the thickness direction. The first stage applies 100±5 bar of high-pressure hydroentangling to the front of the web, with the high-pressure water jets vertically impacting the front, driving the short fibers to quickly entangle and compact, forming a dense upper surface layer. The energy of the water flow gradually decreases as it is transferred to the core layer, resulting in only slight entanglement of the core fibers and maximizing the preservation of the loose, porous structure. The second stage applies 100±5 bar of high-pressure hydroentangling to the reverse side of the web, causing a similarly dense entangled layer to form on the lower surface. Simultaneously, the combined energy of the double-sided high pressure strengthens the skeletal entanglement of the long PET fibers in the core layer, preventing delamination of the fabric while maintaining a relatively low fiber density overall. The third stage involves applying low-pressure hydroentanglement at 40±5 bar to both sides of the fiber web simultaneously. The low-energy water flow performs secondary entanglement and anchoring on the surface free fibers on both sides, firmly fixing the surface floating fibers to the fabric body. This reduces the amount of lint during the wiping process from the root, and can effectively replace traditional singeing and ultra-fine water jet surface finishing processes without causing fiber heat damage or a surge in energy consumption.

[0022] The low-shedding nature of this invention, achieved through dry web forming without pulp, avoids the inherent defects of pulp fibers being too short, having weak bonding forces, and being prone to falling off. All fibers are physically entangled through hydroentanglement to form a strong bond. Furthermore, the dry web-forming fibers are arranged in a three-dimensional uniform pattern, resulting in a more stable hydroentanglement force and a fiber bonding strength significantly higher than that of wet hydrogen bonding, further reducing the risk of shedding during wiping.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows: Completely avoids pulp fiber and headstock system: Uses 3-8mm cut Lyocell / viscose short fibers to replace pulp fibers, uses dry carding to form web instead of water-based headstock forming, and does not use singeing or ultra-fine water jet finishing processes. It is fundamentally different from CN111876911A and CN213596554U, and greatly simplifies the process flow.

[0024] Short-cut fibers combined with gradient hydroentangling achieve ultra-low shedding: During gradient hydroentangling, short-cut cellulose fibers (3-8mm) are easily driven by high-pressure water jets to the surface of the web to form a dense entangled structure, while longer PET fibers form a skeletal support in the core layer. This self-assembly mechanism of "short fibers covering long fibers" fundamentally inhibits fiber shedding from the fabric surface.

[0025] Highly versatile process: It uses commercially available lyocell / viscose staple fiber and PET staple fiber, without the need for any special modification or custom fiber, ensuring stable raw material sources and controllable costs.

[0026] This invention breaks through the common technical prejudice in the field that "ultra-low shedding must rely on wet pulp + surface modification process", and for the first time achieves 0.8g / m³ using a pure dry web forming route. 2 The following levels of lint removal do not require specialized flow feeder equipment or subsequent finishing processes, significantly reducing the production threshold and manufacturing cost of high-cleanliness wiping cloths. Detailed Implementation

[0027] The following embodiments further illustrate the technical solution of the present invention, but are not intended to limit the scope of protection of the present invention.

[0028] The specific implementation provides a method for preparing a wet / dry composite gradient-formed spunlace wiping cloth: S1, Fiber mixing: Opening and mixing short-cut cellulose fibers and PET short fibers; S2, Dry web forming: Forming a uniform fiber web by carding or air-jet forming of the mixed fibers; S3, Gradient hydroentangling reinforcement: Reinforcing the fiber web using a three-stage variable pressure hydroentangling process; the first stage applies high-pressure hydroentangling at 100±5 bar from the front side of the fiber web; the second stage applies high-pressure hydroentangling at 100±5 bar from the back side of the fiber web; the third stage applies low-pressure hydroentangling at 40±5 bar simultaneously from both sides of the fiber web; S4, Dehydration and drying: Dehydrating and drying the hydroentangled nonwoven fabric. The entire preparation process does not use a headstock water-medium forming system, nor does it employ singeing or ultrafine water jet modification processes.

[0029] In the specific embodiments, the short-cut cellulose fibers used are selected from one or both of lyocell short fibers and viscose short fibers, with a cut length of 3-8 mm and a fineness of 1.0-2.0 denier. In the specific embodiments, the PET short fibers used have a cut length of 38-51 mm and a fineness of 1.0-2.5 denier. All raw materials, unless otherwise specified, are commercially available.

[0030] The test methods involved in the specific implementation are described below: Fiber density test: The cross-section of the sample was observed using a scanning electron microscope (SEM). The number of fibers per unit area in the surface layer (1 / 10 of the thickness from the surface) and the core layer (1 / 3 of the thickness) was counted, and the average value of 5 fields of view was taken.

[0031] Lint shedding test: Refer to GB / T24218.10-2019 "Textiles - Test Methods - Part 10: Determination of dry lint shedding", and use the dry friction lint shedding method for testing.

[0032] Areal density and thickness testing: Performed in accordance with GB / T24218 series standards.

[0033] Example 1 The wet / dry composite gradient-formed spunlace wiping cloth of this embodiment has the following fiber formulation: Lyocell staple fiber (cut length 5mm, fineness 1.5 denier) : PET staple fiber (cut length 38mm, fineness 1.5 denier) = 40 : 60 (mass ratio). The manufacturing process parameters are: carding machine main cylinder speed 1000rpm, doffer speed 45m / min; first stage spunlace pressure 100bar, equipped with 3 spunlace heads; second stage spunlace pressure 100bar, equipped with 3 spunlace heads; third stage spunlace pressure 40bar, equipped with 2 spunlace heads per side; web conveying speed 20m / min; drying temperature 130℃.

[0034] Performance characterization results: Total areal density 55 g / m³2 Total thickness 0.42mm, surface fiber density 20 fibers / mm 2 Core fiber density: 6 fibers / mm 2 The core fiber density ratio is 3.33:1, and the shedding amount is 0.52g / m². 2 .

[0035] Comparative Example 1 Example 1 was repeated, except that the cutting length of the lyocell staple fibers was adjusted to 10 mm, while the fineness remained at 1.5 denier. All other raw material ratios, process flow, and process parameters were kept consistent with Example 1. This comparative example was used to verify the effect of chopped cellulose fiber length on the formation of a spontaneous stratified gradient structure.

[0036] Performance characterization results: Total areal density 54 g / m³ 2 Total thickness 0.44mm, surface fiber density 12 fibers / mm 2 Core fiber density: 8.1 fibers / mm 2 The core fiber density ratio is 1.48:1, and the shedding rate is 1.32 g / m². 2 .

[0037] Compared to Example 1, when the length of the cellulose short fibers exceeds the 3-8 mm range defined in this invention, the fiber mobility under high-pressure water jet significantly decreases. The spontaneous stratification effect of short fibers enriching the surface layer and long fibers remaining in the core layer is greatly weakened, making it impossible to form a stable density gradient structure of "dense surface layer and loose core layer". The surface-core fiber density ratio decreases from 3.33:1 to 1.48:1, while the amount of lint increases to more than 2.5 times that of Example 1. This result proves that the use of 3-8 mm short cellulose fibers in this invention is the core prerequisite for achieving an integrated fiber density gradient structure and ultra-low lint performance.

[0038] Comparative Example 2 Example 1 was repeated, with the only difference being that the third stage of double-sided low-pressure hydroentangling was omitted, and only the first stage of front-side high-pressure hydroentangling and the second stage of back-side high-pressure hydroentangling were retained. All other raw material ratios, process flows, and process parameters remained the same as in Example 1. This comparative example was used to verify the effect of the third-stage low-pressure hydroentangling process on surface fiber consolidation and reducing shedding.

[0039] Performance characterization results: Total areal density 55 g / m³ 2 Total thickness 0.41mm, surface fiber density 19 fibers / mm 2 Core fiber density: 6.1 fibers / mm 2 The core fiber density ratio is 3.11:1, and the shedding rate is 1.15 g / m². 2 .

[0040] Compared to Example 1, after eliminating the third stage of low-pressure hydroentangling, the surface-core density gradient of the substrate can still be basically formed, but the surface free fibers cannot be entangled and anchored a second time, and the surface floating fibers cannot be effectively fixed to the fabric body, resulting in a 121% increase in lint shedding compared to Example 1. This result proves that the third stage of 40±5 bar double-sided low-pressure hydroentangling can effectively anchor the surface floating fibers without destroying the overall gradient structure, thereby reducing lint shedding from the root cause. It can equivalently replace traditional singeing and ultra-fine water jet surface finishing processes without causing fiber thermal damage or a surge in energy consumption.

[0041] Example 2 The wet / dry composite gradient-formed spunlace wiping cloth of this embodiment has the following fiber formulation: viscose staple fiber (cut length 3mm, fineness 1.2 denier) : PET staple fiber (cut length 45mm, fineness 2.0 denier) = 30 : 70 (mass ratio). Manufacturing process parameters: carding machine main cylinder speed 900rpm, doffer speed 35m / min; first stage spunlace pressure 105bar, equipped with 4 spunlace heads; second stage spunlace pressure 105bar, equipped with 4 spunlace heads; third stage spunlace pressure 45bar, equipped with 3 spunlace heads per side; web conveying speed 18m / min; drying temperature 125℃. Performance characterization results: total areal density 40g / m³. 2 Total thickness 0.31mm, surface fiber density 18 fibers / mm 2 Core fiber density: 5.8 fibers / mm 2 The core fiber density ratio is 3.10:1, and the shedding amount is 0.68g / m². 2 .

[0042] Example 3 The wet / dry composite gradient-formed spunlace wiping cloth of this embodiment has the following fiber formulation: Lyocell staple fiber (cut length 8mm, fineness 2.0 denier) : PET staple fiber (cut length 51mm, fineness 1.0 denier) = 50:50 (mass ratio). The manufacturing process parameters are: carding machine main cylinder speed 1100rpm, doffer speed 55m / min; first stage spunlace pressure 95bar, equipped with 3 spunlace heads; second stage spunlace pressure 95bar, equipped with 3 spunlace heads; third stage spunlace pressure 35bar, equipped with 2 spunlace heads per side; web conveying speed 22m / min; drying temperature 135℃.

[0043] Performance characterization results: Total areal density 70 g / m³ 2 Total thickness 0.55mm, surface fiber density 21 fibers / mm 2 Core fiber density: 6.2 fibers / mm 2 The core fiber density ratio is 3.39:1, and the shedding rate is 0.45g / m². 2 .

[0044] Example 4 The wet / dry composite gradient-formed spunlace wiping cloth of this embodiment has the following fiber formulation: Lyocell / viscose blended short fibers (mass ratio 1:1, cut length 6mm, fineness 1.4 denier) : PET short fibers (cut length 40mm, fineness 1.8 denier) = 60:40 (mass ratio). The manufacturing process parameters are: carding machine main cylinder speed 1000rpm, doffer speed 50m / min; first stage spunlace pressure 100bar, equipped with 4 spunlace heads; second stage spunlace pressure 100bar, equipped with 4 spunlace heads; third stage spunlace pressure 40bar, equipped with 3 spunlace heads per side; web conveying speed 20m / min; drying temperature 130℃.

[0045] Performance characterization results: Total areal density 80 g / m³ 2 Total thickness 0.58mm, surface fiber density 22 fibers / mm 2 Core fiber density: 6.5 fibers / mm 2 The core fiber density ratio is 3.38:1, and the shedding amount is 0.38g / m². 2 .

[0046] Example 5 The wet / dry composite gradient-formed spunlace wiping cloth of this embodiment has the following fiber formulation: viscose staple fiber (cut length 4mm, fineness 1.0 denier): PET staple fiber (cut length 51mm, fineness 2.5 denier) = 45:55 (mass ratio). The manufacturing process parameters are: carding machine main cylinder speed 850rpm, doffer speed 40m / min; first stage spunlace pressure 102bar, equipped with 3 spunlace heads; second stage spunlace pressure 102bar, equipped with 3 spunlace heads; third stage spunlace pressure 38bar, equipped with 2 spunlace heads per side; web conveying speed 19m / min; drying temperature 140℃.

[0047] Performance characterization results: Total areal density 60 g / m³ 2 Total thickness 0.48mm, surface fiber density 19 fibers / mm 2 Core fiber density: 5.7 fibers / mm 2 The core fiber density ratio is 3.33:1, and the shedding amount is 0.55g / m². 2 .

[0048] The fiber density ratio of the core layer in the above five embodiments remained stable within the range of 3.0-3.6:1, and the amount of lint was ≤0.8g / m², falling entirely within the parameter range defined in the claims of this invention. Furthermore, as the proportion of short cellulose fibers increased and the areal density increased, the surface density further improved, and the amount of lint decreased, verifying the stability and controllability of the technical solution of this invention. This gradient structure ensures low lint shedding on the surface layer while the porous core layer can store more cleaning fluid, adapting to the dual needs of dry and wet wiping in precision scenarios.

Claims

1. A wet / dry composite gradient-formed spunlace wiping cloth, characterized in that... It includes an integral structure formed by blending short-cut cellulose short fibers and PET short fibers and then reinforcing it with gradient hydroentangling; the mass mixing ratio of the short-cut cellulose short fibers and PET short fibers is 30:70 to 60:

40. The wiping cloth has a fiber density gradient distribution in the thickness direction: the surface fiber density is 18-22 fibers / mm. 2 The core fiber density is 5-7 fibers / mm. 2 The fiber density ratio of the surface layer to the core layer is (3.0~3.6):1; the surface layer is the area within 1 / 10 of the thickness of the wiping cloth surface, and the core layer is the area within 1 / 3 of the thickness of the wiping cloth in the middle direction of the thickness. The fiber density is obtained by observing and counting the number of fibers per unit area using a cross-sectional scanning electron microscope.

2. The wet / dry composite gradient-formed spunlace wiping cloth as described in claim 1, characterized in that... The chopped cellulose fibers are selected from one or both of lyocell short fibers and viscose short fibers, with a cut length of 3 to 8 mm and a fineness of 1.0 to 2.0 denier.

3. The wet / dry composite gradient-formed spunlace wiping cloth as described in claim 1, characterized in that... The PET short fiber has a cut length of 38–51 mm and a fineness of 1.0–2.5 denier.

4. The wet / dry composite gradient-formed spunlace wiping cloth as described in claim 1, characterized in that... The total areal density of the wiping cloth is 40-80 g / m³. 2 The total thickness is 0.30-0.60mm.

5. The wet / dry composite gradient-formed spunlace wiping cloth as described in claim 1, characterized in that... The lint shedding amount of the wiping cloth is ≤0.8g / m². 2 .

6. The method for preparing the wet / dry composite gradient-formed spunlace wiping cloth according to claim 1, characterized in that... Includes the following steps: S1. Fiber blending: Opening and blending short-cut cellulose fibers with PET short fibers; S2. Dry web formation: The mixed fibers are formed into a uniform fiber web through carding or air-flow web formation processes. S3. Gradient hydroentangling reinforcement: The fiber web is reinforced using a three-stage variable pressure hydroentangling process; the first stage applies 100±5 bar high-pressure hydroentangling from the front of the fiber web; the second stage applies 100±5 bar high-pressure hydroentangling from the back of the fiber web; and the third stage applies 40±5 bar low-pressure hydroentangling from both sides of the fiber web simultaneously. S4. Dehydration and Drying: The hydroentangled nonwoven fabric is dehydrated and dried. The entire preparation process does not use a headstock water-medium forming system, nor does it employ singeing or ultrafine water jet finishing processes.

7. The preparation method of the wet / dry composite gradient-formed spunlace wiping cloth as described in claim 6, characterized in that... The short-cut cellulose fibers described in step S1 are opened before use, with the opening machine operating at a speed of 800-1200 rpm.

8. The preparation method of the wet / dry composite gradient-formed spunlace wiping cloth as described in claim 6, characterized in that... In step S2, the carding machine's main cylinder speed is 800-1200 rpm, and the doffer speed is 30-60 m / min.

9. The method for preparing the wet / dry composite gradient-formed spunlace wiping cloth as described in claim 6, characterized in that... In step S3, the number of water jets in the first and second sections is 3-4 each, with a water jet diameter of 0.12-0.15 mm; the number of water jets on both sides of the third section is 2-3 each; and the conveying speed is 18-22 m / min.

10. The method for preparing the wet / dry composite gradient-formed spunlace wiping cloth as described in claim 6, characterized in that... The drying temperature in step S4 is 120-140℃.