A rapidly dispersible hydroentangled nonwoven material and method of making

Abstract

The application provides a kind of quick dispersion hydroentangled nonwoven material and its preparation method, including 10-40wt% flat viscose fiber, 35-60wt% pretreated wood pulp fiber, 20-25wt% polylactic acid composite fiber;Polylactic acid composite fiber is prepared by the following method: amino silane coupling agent is mixed with alcohol uniformly, mesoporous silica-based molecular sieve is added, and the reaction is carried out under reflux state, the reaction is ended, and then it is cooled to room temperature, filtered, washed and dried to obtain modified mesoporous silica-based molecular sieve;Polylactic acid, modified mesoporous silica-based molecular sieve are mixed uniformly, melt spinning, and cutting to obtain polylactic acid composite fiber. The capillary effect of the modified mesoporous silica-based molecular sieve holes exposed on the surface of the polylactic acid composite fiber after encountering water can improve the interaction between adjacent and contacting fibers and improve the wet strength. Because this capillary suction force is easily invalidated under the action of stirring and shearing, it has good dispersibility, so that the hydroentangled nonwoven material has good dispersibility and excellent wet strength.

Description

Technical Field

[0001] This invention belongs to the field of nonwoven materials technology, specifically relating to a rapidly dispersible spunlace nonwoven material and its preparation method. Background Technology

[0002] Convenient wet wipes made with spunlace nonwoven technology are increasingly favored by consumers, with approximately 72% of spunlace nonwoven fabrics used in disposable wiping materials globally. However, with landfilling and incineration exacerbating urban salt spray and pollution, the post-use disposal of these products is becoming increasingly problematic. Therefore, there is an urgent need for disposable products that can be disposed of without dumping or incineration. An ideal disposal method is to utilize urban sewage treatment systems and residential septic systems. People are accustomed to casually throwing nonwoven products into sewers, forcing public institutions to regularly maintain equipment and unclog sewers, placing a significant burden on the social environment. This necessitates that such nonwoven disposable products possess flushability: they must have sufficient wet strength during use, disperse during flushing into traditional toilets, and then degrade in the sewage system.

[0003] Degradable fiber raw materials such as wood pulp fiber, viscose fiber, polylactic acid fiber, cotton fiber, cellulose fiber, and lyocell fiber are widely used to prepare disposable spunlace nonwoven fabrics. For example, patent CN107419433B discloses a bamboo pulp washable spunlace material and its manufacturing method. The bamboo pulp washable spunlace material is made by wet web forming and hydroentangling process, comprising 10-80% bamboo pulp, 0-60% wood pulp, and 10-60% man-made cellulose fiber by mass percentage. The basis weight of the bamboo pulp washable spunlace material is 40-80 g / m². Patent CN102267256B discloses a washable spunlace nonwoven material and its production method. This invention discloses a washable spunlace nonwoven material and its production method that has high water absorption, soft hand feel, high strength and can be completely biodegradable. It is a spunlace nonwoven fabric made of 17mm cellulose fibers, on which a fluff pulp fiber web is hydroentangled and fixed.

[0004] The above-mentioned spunlace nonwoven materials not only possess the ability to pass through the drain hole at the bottom of a toilet bowl without clogging the sewer, but also reduce environmental pollution and waste accumulation due to the use of biodegradable materials. However, in order to achieve excellent flushability, the fiber raw material is relatively short, the bonding force between fibers is weak, and when the nonwoven fabric is immersed in water, the hydrogen bonds between the fibers are broken by water, resulting in a significant decrease in the wet strength of the nonwoven fabric.

[0005] Therefore, it is necessary to develop a spunlace nonwoven material that has excellent wet strength without affecting its washability. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention provides a rapidly dispersible spunlace nonwoven material and its preparation method. First, a polylactic acid composite fiber is prepared by melt spinning a mesoporous silica molecular sieve modified with an aminosilane coupling agent and polylactic acid. Then, this composite fiber is mixed with viscose fiber and wood pulp fiber to prepare a spunlace nonwoven fabric. During the melt spinning and spunlace nonwoven fabric preparation processes, the surface pores of the modified mesoporous silica molecular sieve are exposed on the surface of the polylactic acid composite fiber. Upon contact with water, the capillary action of water within the modified mesoporous silica molecular sieve can increase the internal pressure of the material, thereby improving the interaction between adjacent and contacting fibers and increasing wet strength. Furthermore, because this capillary force is easily deactivated under stirring and shearing action and exhibits good dispersibility, the rapidly dispersible spunlace nonwoven material of this invention possesses both good dispersibility and excellent wet strength.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] A rapidly dispersible spunlace nonwoven material comprising the following raw materials by weight percentage: 10-40 wt% flat viscose fiber, 35-60 wt% pretreated wood pulp fiber, and 20-25 wt% polylactic acid composite fiber;

[0009] The polylactic acid composite fiber is prepared by a method comprising the following steps:

[0010] (S1) Mix the aminosilane coupling agent with the alcohol evenly, add the mesoporous silica molecular sieve, react under reflux, and after the reaction is completed, cool to room temperature, filter, wash, and dry to obtain the modified mesoporous silica molecular sieve for later use.

[0011] (S2) Mix polylactic acid and modified mesoporous silica molecular sieve evenly, then melt spin and cut to obtain polylactic acid composite fiber.

[0012] In step (S1), the mesoporous silica-based molecular sieve has a particle size of 300-500 nm, an average pore size of 2-10 nm, and a specific surface area of ​​600-1000 m². 2 / g. The aminosilane coupling agent is selected from at least one or a combination of two or more of 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropylmethyldiethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, and N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane. The mass ratio of the aminosilane coupling agent, alcohol, and mesoporous silica-based molecular sieve is 1:15-25:0.25-0.5.

[0013] In step (S1), the reaction time is 10-24 hours, the washing is performed 1-3 times with anhydrous ethanol, and the drying temperature is 60-80℃. The surface polarity of the mesoporous silica molecular sieve is altered by modifying it with an aminosilane coupling agent, thereby improving its dispersibility in polylactic acid.

[0014] The alcohol is not particularly limited, and includes, but is not limited to, one or a combination of two of ethanol and isopropanol.

[0015] In step (S2), the polylactic acid melt index is 20-30 g / 10 min·210℃. The mass ratio of polylactic acid to modified mesoporous silica-based molecular sieve is 100:5-8.

[0016] In step (S2), the melt spinning process includes the following steps: melt extrusion, fiber forming, fiber cooling, winding, stretching and shaping, and filament production. In the process of preparing polylactic acid composite fibers, the amount of modified mesoporous silica-based molecular sieve is crucial. Too much will significantly improve the bending deformation resistance of polylactic acid composite fibers, making it difficult to break capillary adhesion and causing a decrease in dispersion. Too little will not improve wet strength. Therefore, this parameter needs to be strictly controlled.

[0017] The melt extrusion process utilizes a single-screw extruder with a screw length-to-diameter ratio of 24-36. The temperatures in zones one (190-210℃), two (210-220℃), and three (220-250℃) are as follows: the metering pump temperature is 220-250℃, and the meltblown die temperature is 220-250℃. The meltblown die orifice diameter is 0.2-0.35mm, and the length-to-diameter ratio is 2-4. The screw speed is 30-42 rpm, the spinning speed is 2000-3000 m / min, the stretching and setting temperature is 100-110℃, and the stretching ratio is 1-3.5 times. Fiber cooling is achieved using air cooling at 15-20℃, with the air cooler 50-120mm away from the meltblown die, and the air flow rate is 0.5-1 m / s.

[0018] The polylactic acid composite fiber has an average diameter of 5-10 μm and a length of 6-12 mm.

[0019] The flat viscose fiber has a fineness of 1.5-2.8 dtex, a length of 10-15 μm, and a width of 1-5 μm.

[0020] The pretreated wood pulp fiber is obtained by adding water to the wood pulp fiber for pulping treatment, followed by drying; the wood pulp fiber length is 2-8 mm; the pulping degree in the pulping treatment is 40-60°SR, the pulping concentration is 4-5 wt%, and the pulping wet weight is controlled at 8.5-9.5 g; the wood pulp fiber is selected from one or a combination of two types of softwood pulp fiber and hardwood pulp fiber.

[0021] The present invention also provides a method for preparing the above-mentioned rapidly washable spunlace nonwoven material, comprising the following steps:

[0022] Flat viscose fibers, pretreated wood pulp fibers, and polylactic acid composite fibers are loosely mixed to prepare a mixed pulp. The mixed pulp is pumped to an inclined wire forming system to output a wet fiber web. The web is then hydroentangled and reinforced on a flat wire, hydroentangled and reinforced on a rotary drum, dehydrated, dried, and wound.

[0023] The concentration of the mixed pulp is 0.4-1 g / L. The flat-web hydroentangling reinforcement process involves: water needles perpendicular to the fiber web, hydroentangling pressure of 30-80 bar, water needle hole diameter of 0.1-0.15 mm, 3-5 hydroentangling passes, with each pass gradually increasing in increments of 5-15 bar, a conveyor speed of 5-20 m / min, and a hydroentangling distance of 30-40 mm. The rotary drum hydroentangling reinforcement process involves: hydroentangling pressure of 30-80 bar, water needle hole diameter of 0.1-0.15 mm, and 1-3 hydroentangling passes. Dewatering involves removing excess water using a suction device. The drying temperature is 70-130℃, and the drying time is 5-15 seconds.

[0024] Compared with the prior art, the beneficial effects of the present invention are:

[0025] This invention first uses an aminosilane coupling agent-modified mesoporous silica molecular sieve and polylactic acid (PLA) to produce PLA composite fibers through melt spinning. These fibers are then mixed with viscose fibers and wood pulp fibers to prepare spunlace nonwoven fabrics. During melt spinning and spunlace nonwoven fabric preparation, the surface pores of the modified mesoporous silica molecular sieve are exposed on the surface of the PLA composite fibers. Upon contact with water, the capillary action of water within the modified mesoporous silica molecular sieve can pressurize the material internally, thereby increasing the interaction between adjacent and contacting fibers and improving wet strength. Furthermore, because this capillary force is easily deactivated under stirring and shearing, and exhibits good dispersibility, the rapidly dispersible spunlace nonwoven material of this invention possesses both good dispersibility and excellent wet strength. Detailed Implementation

[0026] The present invention will be further described below with reference to specific embodiments, but is not limited to the contents of the specification. Unless otherwise specified, all "parts" mentioned in the embodiments of the present invention are parts by weight. All reagents used are commercially available in the art.

[0027] The mesoporous silica-based molecular sieve, type A, MCM-41, was purchased from Shanghai Juna Technology Co., Ltd., with a particle size of 500 nm, an average pore size of 3.4 nm, and a specific surface area of ​​900 m². 2 / g.

[0028] Mesoporous silica-based molecular sieve SBA-15, purchased from Shanghai Zhenzhun Biotechnology Co., Ltd., has a particle size of 300 nm, an average pore size of 2.0 nm, and a specific surface area of ​​650 m².2 / g.

[0029] Polylactic acid spherical particles with a melt index of 25.1 g / 10 min·210℃ were purchased from Natureworks, USA.

[0030] The wood pulp fiber is hardwood pulp fiber, purchased from Hangzhou Xiangfu Wood Pulp Fiber Manufacturing Co., Ltd., with an average length of 4.1 mm.

[0031] The flat viscose fiber has a fineness of 2.4 dtex, a length of 15 μm and a width of 3.7 μm, and was purchased from Kelhein GmbH, Germany.

[0032] 2.5 dtex circular viscose fiber, 13 μm long, purchased from Daiwa Textile Co., Ltd.

[0033] Preparation of rapid-dispersible spunlace nonwoven materials

[0034] Example 1

[0035] (1) Mix 100 parts of 3-aminopropyltrimethoxysilane with 2000 parts of anhydrous ethanol evenly, add 50 parts of mesoporous silica molecular sieve MCM-41, heat to 70℃, react under reflux for 12h, after the reaction is completed, cool to room temperature, filter, wash 3 times with anhydrous ethanol, and dry under vacuum at 80℃ to constant weight to obtain modified mesoporous silica molecular sieve for later use.

[0036] (2) Mix 100 parts of polylactic acid and 8 parts of modified mesoporous silica molecular sieve evenly, and then melt spin them to cut polylactic acid composite fibers with an average diameter of 6.5 μm and a length of 10 mm. The melt spinning process includes the following steps: melt extrusion, fiber forming, fiber cooling, winding, stretching and shaping, and filament.

[0037] The melt extrusion process utilizes an SJ-30 single-screw extruder with an L / D ratio of 28:1. The temperatures are as follows: Zone 1: 200℃; Zone 2: 220℃; Zone 3: 230℃; Metering pump temperature: 235℃; Meltblown die temperature: 235℃. The meltblown die has an orifice diameter of 0.3mm and an L / D ratio of 4. The screw speed is 35rpm, the spinning speed is 2000m / min, the stretching and setting temperature is 100℃, and the stretch ratio is 3. Fiber cooling is achieved using 20℃ air cooling, with the air cooler 80mm from the meltblown die and a flow rate of 1m / s.

[0038] (3) Add water to 100 parts of wood pulp fiber for pulping treatment. The degree of pulping is 47.5°SR, the pulping concentration is 5wt%, the pulping wet weight is controlled at 9.0g, and then dry to obtain dried pretreated wood pulp fiber for use.

[0039] (4) 15 parts of flat viscose fiber, 60 parts of pretreated wood pulp fiber, and 25 parts of polylactic acid composite fiber were loosely mixed to prepare a mixed pulp with a concentration of 0.4 g / L. The mixed pulp was pumped into an inclined wire forming system, and a wet-laid fiber web was output. The web was then hydroentangled and reinforced in a flat wire, followed by a drum hydroentanglement process. Excess moisture was removed by a suction device, and the web was dried at 110°C for 10 seconds. The resulting web was wound to obtain a basis weight of 64.5 g / m². 2 .

[0040] The flat web hydroentangling reinforcement process involves water needles perpendicular to the fiber web, with the first hydroentangling pressure at 30 bar, the second at 40 bar, the third at 50 bar, the fourth at 55 bar, and the fifth at 60 bar, and a water needle hole diameter of 0.12 mm. The conveyor belt speed is 20 m / min, and the hydroentangling distance is 40 mm. The rotary drum hydroentangling reinforcement process uses a hydroentangling pressure of 40 bar and a water needle hole diameter of 0.12 mm.

[0041] Example 2

[0042] The rest is the same as in Example 1, except that in step (1), mesoporous silica molecular sieve MCM-41 is replaced with mesoporous silica molecular sieve SBA-15 of equal mass.

[0043] Example 3

[0044] The rest is the same as in Example 1, except that the amount of mesoporous silica-based molecular sieve used in step (1) is 25 parts.

[0045] Example 4

[0046] The rest is the same as in Example 1, except that the amount of modified mesoporous silica-based molecular sieve used in step (2) is 5 parts.

[0047] Example 5

[0048] The rest is the same as in Example 1, except that the amount of modified mesoporous silica-based molecular sieve used in step (2) is 3 parts.

[0049] Example 6

[0050] The rest is the same as in Example 1, except that the amount of modified mesoporous silica-based molecular sieve in step (2) is 10 parts.

[0051] Example 7

[0052] The rest is the same as in Example 1, except that in step (4), 20 parts of viscose fiber, 60 parts of pretreated wood pulp fiber, and 20 parts of polylactic acid composite fiber are loosely mixed to prepare a mixed pulp. The mixed pulp is pumped to the inclined wire forming system, and a wet-laid fiber web is output. The web is then reinforced with hydroentangling on a flat wire and hydroentangling on a rotary drum. Excess water is removed by a suction device, and the web is dried at 110°C for 10 seconds. The web is then wound to obtain a basis weight of 63 g / m². 2 .

[0053] Example 8

[0054] The rest is the same as in Example 1, except that in step (4), 40 parts of viscose fiber, 35 parts of pretreated wood pulp fiber, and 25 parts of polylactic acid composite fiber are loosely mixed to prepare a mixed pulp. The mixed pulp is pumped to the inclined wire forming system, and a wet-laid fiber web is output. The web is then reinforced with hydroentangling on a flat wire and hydroentangling on a rotary drum. Excess water is removed by a suction device, and the web is dried at 110°C for 10 seconds. The web is then wound to obtain a basis weight of 64 g / m². 2 .

[0055] Comparative Example 1

[0056] (1) 100 parts of polylactic acid were melt-spun and cut into polylactic acid fibers with an average diameter of 6.5 μm and a length of 10 mm.

[0057] (2) Add water to 100 parts of wood pulp fiber for pulping treatment. The degree of pulping is 47.5°SR, the pulping concentration is 5wt%, the pulping wet weight is controlled at 9.0g, and then dry to obtain dried pretreated wood pulp fiber for use.

[0058] (3) 15 parts viscose fiber, 60 parts pretreated wood pulp fiber, and 25 parts polylactic acid fiber were loosely mixed to prepare a mixed pulp. The mixed pulp was pumped into an inclined wire forming system to output a wet-laid fiber web. The web was then reinforced with hydroentangling on a flat web and hydroentangling on a rotary drum. Excess moisture was removed by a suction device, and the web was dried at 110°C for 10 seconds. The web was then wound to obtain a basis weight of 65 g / m². 2 .

[0059] The process includes: Flat web hydroentangling reinforcement: the hydroentangling needles are perpendicular to the fiber web; the first hydroentangling pressure is 30 bar, the second is 40 bar, the third is 50 bar, the fourth is 55 bar, and the fifth is 60 bar; the needle hole diameter is 0.12 mm. The conveyor belt speed is 20 m / min, and the hydroentangling distance is 40 mm. Rotary drum hydroentangling reinforcement: the hydroentangling pressure is 40 bar, and the needle hole diameter is 0.12 mm.

[0060] Comparative Example 2

[0061] The rest is the same as in Example 1, except that in step (4), 10 parts of viscose fiber, 60 parts of pretreated wood pulp fiber, and 30 parts of polylactic acid composite fiber are loosely mixed to prepare a mixed pulp. The mixed pulp is pumped into a slanted wire forming system, output as a wet-laid fiber web, reinforced with a flat wire by hydroentangling, reinforced with a rotary drum by hydroentangling, and excess water is removed by a suction device. The web is dried at 110°C for 10 seconds and wound to obtain a basis weight of 62.8 g / m². 2 .

[0062] Comparative Example 3

[0063] The rest is the same as in Example 1, except that in step (4), the flat viscose fibers are replaced with round viscose fibers of equal mass.

[0064] The nonwoven materials prepared in the above embodiments and comparative examples were subjected to the following performance tests:

[0065] Dispersion performance: The dispersion performance was tested according to standard JISP8135-1998. The sample size was 100mm×100mm. It was put into a beaker containing 300mL of deionized water and stirred with a magnetic stirrer at a rotor speed of 600r / min. The dispersion state of the nonwoven fabric was observed visually at regular intervals, and the time required for the nonwoven fabric to reach dispersion was determined accordingly.

[0066] If the dispersion time is less than 150 seconds, it is considered that the water is dispersible, with a preferred value of less than 100 seconds.

[0067] To facilitate result evaluation, the results were graded into six levels: 0, 1, 2, 3, 4, and 5, based on the dispersion time and the integrity of the fabric surface after stirring.

[0068] Level 0 - No dispersion after 150 seconds, fabric surface intact.

[0069] Level 1 - No dispersion after 100s, dispersion at the edges of the fabric after 150s, but the overall fabric surface remains intact.

[0070] Level 2 - It begins to disperse after 100 seconds, and a small portion disperses after 150 seconds, leaving a few holes on the fabric surface.

[0071] Level 3 - begins to disperse after 100 seconds, and most disperses after 150 seconds, leaving numerous holes on the fabric surface.

[0072] Level 4: Partial dispersion after 100s, and dispersion into strips after 150s.

[0073] Level 5 - Within 100 seconds, the fabric sample completely dispersed into clumps.

[0074] Wet tensile strength: According to standard GB / T 24328.3-2020 Determination of tensile strength, elongation at maximum force and tensile energy absorption of toilet paper and its products, the sample was bent into a ring and immersed in distilled water or deionized water for 5 minutes. After taking it out, the surface water was gently wiped off with filter paper. The sample size was 50mm×150mm, the tensile clamping distance was 100mm, the tensile rate was 50mm / min, and the test environment temperature was 20℃ and the humidity was 65%RH.

[0075] Stiffness test: Refer to ZBW 04003-1987 Fabric Stiffness Test Method Inclined cantilever method, cut samples with an area of ​​20cm*2.5cm in both the longitudinal and transverse directions for testing.

[0076] Table 1 Performance Test Results

[0077]

[0078]

[0079] As can be seen from Table 1, the spunlace nonwoven material prepared by the present invention using flat viscose fiber, pretreated wood pulp fiber, and polylactic acid composite fiber prepared by melt spinning of polylactic acid and modified mesoporous silica molecular sieve as raw materials effectively balances the washability and strength of spunlace nonwoven fabric, achieving a unity of washability and strength.

[0080] The stiffness test results of Example 1 and Comparative Example 3 show that the spunlace nonwoven material prepared by the flat viscose fiber of the present invention has lower stiffness and is more flexible.

Claims

1. A hydroentangled nonwoven material that can be quickly dispersed, characterized in that, The raw materials include the following weight percentages: 10-40 wt% flat viscose fiber, 35-60 wt% pretreated wood pulp fiber, and 20-25 wt% polylactic acid composite fiber; The polylactic acid composite fiber is prepared by a method comprising the following steps: (S1) The aminosilane coupling agent and alcohol are mixed evenly, and then added to the mesoporous silica molecular sieve. The reaction is carried out under reflux. After the reaction is completed, the mixture is cooled to room temperature, filtered, washed, and dried to obtain the modified mesoporous silica molecular sieve for later use. The mesoporous silica molecular sieve has a particle size of 300-500 nm, an average pore size of 2-10 nm, and a specific surface area of ​​600-1000 m². 2 / g; (S2) Polylactic acid and modified mesoporous silica molecular sieve are mixed evenly, and then melt-spun and cut to obtain polylactic acid composite fiber; the mass ratio of polylactic acid and modified mesoporous silica molecular sieve is 100:5-8.

2. The rapidly dispersible spunlace nonwoven material according to claim 1, characterized in that, In step (S1), the mass ratio of the aminosilane coupling agent, alcohol, and mesoporous silica-based molecular sieve is 1:15-25:0.25-0.

5.

3. The rapidly dispersible spunlace nonwoven material according to claim 1, characterized in that, In step (S1), the aminosilane coupling agent is selected from at least one or a combination of two or more of 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropylmethyldiethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, and N-(2-aminoethyl)-3-aminopropylmethyldiethoxysilane.

4. The rapidly dispersible spunlace nonwoven material according to claim 1, characterized in that, In step (S2), the polylactic acid melt index is 20-30 g / 10 min·210℃.

5. The rapidly disintegrating spunlace nonwoven material according to claim 1, characterized in that, In step (S2), the melt spinning process includes the following steps: melt extrusion, fiber forming, fiber cooling, winding, stretching and shaping, and filament production.

6. The rapidly dispersible spunlace nonwoven material according to claim 5, characterized in that, The melt extrusion uses a single-screw extruder with a screw length-to-diameter ratio of 24-36. The temperature in zone one is 190-210℃, zone two is 210-220℃, zone three is 220-250℃, the metering pump temperature is 220-250℃, and the meltblown die temperature is 220-250℃. The meltblown die orifice diameter is 0.2-0.35mm, and the length-to-diameter ratio is 2-4. The screw speed is 30-42rpm, the spinning speed is 2000-3000m / min, the stretching and setting temperature is 100-110℃, and the stretching ratio is 1-3.5 times. The fiber cooling uses air cooling at 15-20℃, the air cooling distance from the meltblown die is 50-120mm, and the air cooling flow rate is 0.5-1m / s.

7. The rapidly dispersible spunlace nonwoven material according to claim 1, characterized in that, The polylactic acid composite fiber has an average diameter of 5-10 μm and a length of 6-12 mm.

8. The rapidly disintegrating spunlace nonwoven material according to claim 1, characterized in that, The pretreated wood pulp fiber is obtained by adding water to the wood pulp fiber for pulping treatment, followed by drying; the wood pulp fiber length is 2-8 mm; the pulping treatment has a freeness of 40-60°SR, a pulping concentration of 4-5 wt%, and a pulping wet weight controlled at 8.5-9.5 g; the wood pulp fiber is selected from one or a combination of two types of softwood pulp fiber and hardwood pulp fiber.

9. A method for preparing a rapidly washable spunlace nonwoven material according to any one of claims 1-8, characterized in that, Includes the following steps: Flat viscose fibers, pretreated wood pulp fibers, and polylactic acid composite fibers are loosely mixed to prepare a mixed pulp. The mixed pulp is pumped to an inclined wire forming system to output a wet fiber web. The web is then hydroentangled and reinforced on a flat wire, hydroentangled and reinforced on a rotary drum, dehydrated, dried, and wound.

10. The preparation method according to claim 9, characterized in that, The concentration of the mixed pulp is 0.4-1 g / L; the flat web hydroentangling reinforcement process is as follows: the water needles are perpendicular to the fiber web, the hydroentangling pressure is 30-80 bar, the water needle hole diameter is 0.1-0.15 mm, the number of hydroentangling passes is 3-5, and the pressure between each hydroentangling pass gradually increases by 5-15 bar, the conveyor speed is 5-20 m / min, and the hydroentangling distance is 30-40 mm; the rotary drum hydroentangling reinforcement process is as follows: the hydroentangling pressure is 30-80 bar, the water needle hole diameter is 0.1-0.15 mm, and the number of hydroentangling passes is 1-3; the dewatering is performed by removing excess water through a suction device; the drying temperature is 70-130℃, and the drying time is 5-15 s.

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