Elastic wet-process spunlace non-woven fabric made of ultra-short fibers compounded with polyolefin elastic fibers and preparation method of elastic wet-process spunlace non-woven fabric

Abstract

The invention relates to an elastic wet spunlace non-woven fabric made of ultra-short fibers compounded with polyolefin elastic fibers and a preparation method of the elastic wet spunlace non-woven fabric. The elastic wet spunlace non-woven fabric is made of the ultra-short fibers and the polyolefin elastic fibers through a wet spunlace process. Wherein the polyolefin elastic fibers are reinforced into a loose three-dimensional net-shaped structure through hot-melt spinning and hot bonding, and the ultra-short fibers are selected from one or combination of cellulosic fibers and polyester fibers and are arranged into the three-dimensional net-shaped structure in a wet-process net forming mode. The prepared elastic wet spunlace non-woven fabric has elasticity in the longitudinal direction, the transverse direction and the cross direction. According to the product prepared by the invention, the polyolefin elastic fiber filament is used as a skeleton structure and is compounded with the cellulose fiber, the polyester fiber and other ultra-short fibers, so that the longitudinal and transverse tensile elasticity of the material is realized while better hygroscopicity, air permeability and softness are maintained.

Description

Technical Field

[0001] This invention belongs to the field of nonwoven fabric production technology, and relates to an elastic wet-laid spunlace nonwoven fabric made of ultra-short fiber composite polyolefin elastic fiber and its preparation method. Background Technology

[0002] With the rapid development of nonwoven fabric technology, the demand for elastic nonwoven fabrics is increasing in fields such as beauty products, hygiene products, medical dressings, and industrial filtration. However, traditional elastic nonwoven fabric manufacturing technologies still have significant limitations, mainly in the following aspects: Limited and singular elastic properties: Most existing elastic nonwoven fabrics adopt a unidirectional stretching design (such as longitudinal elasticity), with weak transverse elasticity, making it difficult to achieve isotropic elasticity. For example, some products have low longitudinal tensile elongation at break and large fluctuations in recovery rate after stretching, resulting in easy deformation and insufficient rebound during use, affecting comfort and durability.

[0003] Complex processes and high energy consumption: Traditional manufacturing methods such as spunbond, meltblown, and hot rolling are characterized by high energy consumption and low production efficiency due to their multi-step processes. For example, when wet web forming is combined with hydroentangling, it involves complex steps such as fiber dispersion, dehydration, multi-layer composite, and thermal bonding. The process is difficult to control, and improper control of the hydroentangling pressure gradient can easily lead to fiber damage or insufficient entanglement, affecting the uniformity and strength of the product.

[0004] Material selection limitations: Existing technologies mostly use single elastomers (such as polyurethane and spandex) or fibers (such as polyester and viscose), resulting in poor material compatibility and difficulty in balancing elasticity, strength, and environmental friendliness. For example, although polyolefin elastomers have good elasticity, traditional hot melt spinning processes are prone to excessive stretching, leading to a decrease in elasticity; short fibers (such as cellulose fibers) are prone to agglomeration during wet web forming, affecting the uniformity of the fiber web.

[0005] Environmental and cost challenges: Some processes rely on chemical adhesives or solvents, posing environmental pollution risks. Furthermore, the high cost of high-performance elastomers limits their large-scale application in areas such as disposable hygiene products. In addition, traditional production lines have low levels of automation and require significant manual intervention, resulting in poor product performance stability and a high defect rate.

[0006] Poor product performance stability: Existing elastic nonwoven fabrics exhibit significant fluctuations in key indicators such as tensile breaking elongation, recovery rate, and unit area mass, affecting product consistency and reliability.

[0007] Furthermore, the existing technology for preparing and constructing elastic nonwoven fabrics has significant limitations: For example, in prior art document 1 (patent number CN119433839A), spunbond layers with different elasticities are composited by spunbond process, which can only achieve quantitative elasticity in the transverse direction, while the elasticity in the longitudinal and cross directions is missing. Moreover, the elasticity performance depends on the interlayer composite structure, and the space for elasticity upgrade is limited. Some existing technologies may use a process of melting elastic membranes and hot-melting nonwoven webs to bond and perforate the composite unit, which has low elasticity transfer efficiency and insufficient fiber-level elasticity performance because the composite unit is a membrane material and a nonwoven web. Some existing technologies use TPU spunbond process to prepare elastic nonwoven fabrics, which are essentially single-component spunbond fabrics. Their categories are limited to spunbond systems and lack the fiber entanglement network advantages unique to wet hydroentanglement process. In some existing technologies, elasticity is achieved through polyester yarn knitting, which relies on the knitting structure to achieve deformation. The elastic performance depends on the yarn-level deformation, and the elastic efficiency and all-directional elastic performance are limited.

[0008] The aforementioned technologies may have problems such as a single elastic direction, crude composite structure, and limited processing types, making it difficult to meet the application scenarios of composite materials with high elasticity and multi-dimensional elasticity requirements.

[0009] To address this issue, an elastic wet-laid spunlace nonwoven fabric composed of ultra-short fiber composite polyolefin elastic fiber and its preparation method were designed to overcome the aforementioned problems. Summary of the Invention

[0010] The purpose of this invention is to overcome the shortcomings of existing technologies and provide an elastic wet-laid spunlace nonwoven fabric composed of ultra-short fiber composite polyolefin elastic fiber and its preparation method. The product prepared by this invention uses polyolefin elastic fiber filaments as the skeleton structure, composited with ultra-short fibers such as cellulose fibers and polyester fibers, maintaining good moisture absorption, breathability, and softness while achieving longitudinal and transverse tensile elasticity of the material.

[0011] This invention is achieved through the following technical solution: an elastic wet-spunlace nonwoven fabric composed of ultra-short fiber and polyolefin elastic fiber, wherein the elastic wet-spunlace nonwoven fabric is made of ultra-short fiber and polyolefin elastic fiber by wet-spunlace process, wherein the polyolefin elastic fiber is formed into a relaxed three-dimensional network structure by hot melt spinning and thermal bonding, and the ultra-short fiber is selected from one or a combination of cellulose fiber and polyester fiber, and is arranged into a three-dimensional network structure by wet web forming, so that the prepared elastic wet-spunlace nonwoven fabric has all-directional elasticity in the longitudinal, transverse and cross directions.

[0012] Preferably, the polyolefin elastic fiber has a mass percentage of 25% to 60%, the ultra-short fiber has a mass percentage of 40% to 75%, and the unit area mass of the elastic wet-laid spunlace nonwoven fabric is 35 to 80 g / m².

[0013] Preferably, the longitudinal tensile elongation at break of the elastic wet-spunlace nonwoven fabric of the ultra-short fiber composite polyolefin elastic fiber is 180-200%, the length recovery rate at 100% elongation is 97-99%, the transverse tensile elongation at break is 60-90%, and the length recovery rate at 70% elongation is 92-97%.

[0014] Preferably, the ultrashort fibers have a fineness of 0.1–1.2 dtex and a length of 3–6 mm.

[0015] Preferably, the spacing between the reinforcement points in the three-dimensional mesh structure is 1.5–2.5 mm, and the area of ​​each reinforcement point is 0.20–0.36 mm². 2 .

[0016] A method for preparing an elastic wet-laid spunlace nonwoven fabric includes the following steps: 1) The short fibers are pre-dispersed in a fiber dispersion device to ensure that the fibers in the fiber suspension are evenly dispersed in the water; 2) The fiber suspension is diluted and then fed into the inclined wire mesh forming machine by a slurry pump to dehydrate and form a web to make a wet fiber layer; 3) Polyolefin elastic fibers are hot melt spun, crimped and laid into a network structure, and fed into a hot bonding equipment in a relaxed state for low-pressure hot melt bonding to form a network skeleton structure, providing an elastic body. The network skeleton structure is then wound into a roll of material. 4) The polyolefin elastic fiber roll is unwound and conveyed, and then stacked with the first wet-process ultra-short fiber layer. Because the polyolefin elastic fiber has elasticity and stickiness, the polyolefin elastic fiber layer is actively separated by an L-shaped peeling roller. 5) The two layers of material are overfed into the hydroentangled flat net support curtain, and the superimposed material is hydroentangled in four stages using a decreasing low-pressure hydroentanglement process, so that the ultra-short fibers penetrate into the gaps of the polyolefin elastic fiber network skeleton structure layer and form entanglement points with the polyolefin elastic fibers. 6) Remove moisture from the two hydroentangled layers by vacuum suction or rolling mill, collect them into rolls, unwind them a second time, and enter the composite conveyor curtain to overlap with the second layer of ultra-short fiber web. Under the action of secondary decreasing low-pressure hydroentangling, a three-layer structure is formed with ultra-short fibers in the upper and lower layers and polyolefin elastic fibers in the middle layer. 7) The three-layer structure material after hydroentangling is dehydrated by vacuum suction or roller drying, and then dried at low tension and temperature and rolled into rolls to produce an elastic wet hydroentangling nonwoven fabric with a unit area mass of 35-80g / ㎡ of ultra-short fiber composite polyolefin elastic fiber.

[0017] Preferably, in step 1), the fiber spreading device is equipped with two sets of rotating blades, one upper and one lower. Each set of rotating blades has two symmetrical blades with an angle of 8-10°. The upper blade has a blade thickness of 0.8-1.2 mm, and the lower blade has a blade thickness of 1.5-1.9 mm. The spreading concentration of the fiber suspension is 0.2-0.5%, and the spreading device rotates at 600-1000 r / min, with each spreading session lasting 9-10 minutes. In step 3), the polyolefin elastic fiber spinning and laying speed is 101-102% of the conveyor curtain speed, causing the polyolefin elastic fiber to flocculate into a curled state. The speed of the bonding roller in the thermal bonding device is lower than the feeding speed of the conveyor curtain to avoid stretching of the polyolefin elastic fiber and reducing its elasticity. The bonding roller in the thermal bonding device consists of a steel roller and a patterned roller. The surface of the patterned roller is covered with protrusions with a height of 0.4-0.6 mm, a width of 0.4-0.6 mm, and a spacing of 1.5-2.5 mm. The protrusions are rhomboid or elliptical in shape.

[0018] Preferably, in step 4), the polyolefin elastic fiber unwinding is performed using an L-shaped peeling roller to actively separate the polyolefin elastic fiber layer. The linear speed of the peeling roller is 100.3% to 100.5% of the speed of the composite conveyor curtain, so that after the modified polypropylene skeleton layer is actively peeled, it shrinks and rebounds to a relaxed state through speed difference overfeeding, and then overlaps with the first layer of ultra-short fiber layer. Preferably, step 5) employs a decreasing low-pressure hydroentangling process to perform four hydroentangling passes on the two-layered material. The pressure of the first hydroentangling pass is 30-35 bar, the pressure of the second hydroentangling pass is 28-32 bar, the pressure of the third hydroentangling pass is 26-30 bar, and the pressure of the fourth hydroentangling pass is 26 bar. This is combined with high negative pressure suction dehydration, which causes the upper ultra-short fibers and polyolefin elastic fibers to interweave and entangle.

[0019] Preferably, the drying temperature in step 7) is 103-108°C, which is used in conjunction with low-tension stretching to allow the material to shrink further, thereby providing higher elasticity and softness.

[0020] The beneficial effects of this invention are as follows: This invention achieves multi-dimensional elasticity upgrades and process innovation through a wet hydroentangling composite process of ultra-short fibers and polyolefin elastic fibers: 1) Breakthrough in all-directional elasticity: Through a three-dimensional mesh structure design, combined with longitudinal elongation at break of 180-200% (recovery rate of 97-99%), transverse elongation at break of 60-90% (recovery rate of 92-97%), and cross-directional elasticity, it achieves three-dimensional synergistic elasticity in the longitudinal, transverse, and cross directions, breaking through the limitations of traditional unidirectional elasticity. 2) Optimized elasticity efficiency: Ultra-short fibers (0.1-1.2 dtex, 3-6 mm) and polyolefin elastic fibers (25-60% by mass) form entanglement points through a decreasing low-pressure hydroentangling process (30-35 bar → 26 bar in four decreasing stages), combined with a three-dimensional network with a reinforcement spacing of 1.5-2.5 mm, achieving a composite of elastomer and fiber, resulting in more complete elastic performance; 3) Process innovation: Wet hydroentangling process is used to replace traditional spunbond / meltblown process. Combined with L-shaped peeling roller speed difference overfeed (100.3~100.5% speed matching) to achieve relaxed state lamination, and low tension fine temperature drying at 103~108℃ to avoid melt-breaking damage and improve elasticity and softness. 4) Performance balance: At a unit area mass of 35-80 g / m², the mass ratio of polyolefin elastic fiber to ultra-short fiber (25-60%: 40-75%) is optimized to balance elastic recovery rate and material strength, while avoiding fiber loss and improving the production yield. 5) Application expansion: Suitable for high-elasticity demand scenarios (such as medical materials, beauty products, hygiene products, flexible packaging), it maximizes the deformation space through three-dimensional elastic network to meet complex deformation requirements.

[0021] This invention, through innovation in three dimensions—process, structure, and performance—solves problems such as the single elastic direction of existing elastic nonwoven fabrics, coarse composite structures, insufficient elastic efficiency, damage to the transport of polyolefin elastic fiber filaments, and decreased elasticity of composites of ultra-short fibers and polyolefin elastic fibers. It achieves a dual improvement in elasticity and process efficiency. Utilizing this invention, the material's elasticity is maximized, and the curly, plush-like free fiber web can hold more essence and release liquid quickly. When used as a face mask, it extends the skin-adhering time and maximizes the efficacy of the essence. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the overall process of the present invention; Figure 2 This is a top view of the product prepared according to the present invention; Figure 3 This is a cross-sectional view of the product prepared according to the present invention. Detailed Implementation

[0023] To enable those skilled in the art to more clearly understand the purpose, technical solution, and advantages of the present invention, the present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0024] In the description of this invention, it should be understood that the orientation or positional relationship indicated by terms such as "upper", "lower", "left", "right", "inner", "outer", "lateral", and "vertical" is based on the orientation or positional relationship shown in the accompanying drawings and is only for the convenience of describing this invention, and is not intended to indicate or imply that the device or component referred to must have a specific orientation, and therefore should not be construed as a limitation of this invention.

[0025] The invention will now be described in detail with reference to the accompanying drawings: Figure 1-3 As shown, an elastic wet-spunlace nonwoven fabric composed of ultra-short fiber and polyolefin elastic fiber is disclosed. The elastic wet-spunlace nonwoven fabric is made of ultra-short fiber and polyolefin elastic fiber using a wet-spunlace process. The polyolefin elastic fiber is formed into a relaxed three-dimensional network structure by hot melt spinning and thermal bonding. The ultra-short fiber is selected from one or a combination of cellulose fiber and polyester fiber and is arranged into a three-dimensional network structure by wet-laid method, so that the prepared elastic wet-spunlace nonwoven fabric has all-directional elasticity in the longitudinal, transverse and cross directions.

[0026] The polyolefin elastic fiber comprises 20%–60% by mass, the short fiber comprises 40%–75% by mass, and the unit area mass of the elastic wet-laid spunlace nonwoven fabric is 35–80 g / m². The longitudinal tensile elongation at break of the short fiber composite polyolefin elastic fiber elastic wet-laid spunlace nonwoven fabric is 180–200%, the length recovery rate at 100% elongation is 97–99%, the transverse tensile elongation at break is 60–90%, and the length recovery rate at 70% elongation is 92–97%. The short fiber has a fineness of 0.1–1.2 dtex and a length of 3–6 mm. The spacing between the reinforcement points in the three-dimensional mesh structure is 1.5–2.5 mm, and the area of ​​each reinforcement point is 0.20–0.36 mm². 2 .

[0027] A method for preparing an elastic wet-laid spunlace nonwoven fabric includes the following steps: 1) The short fibers are pre-dispersed in a fiber dispersion device to ensure that the fibers in the fiber suspension are evenly dispersed in the water; 2) The fiber suspension is diluted and then fed into the inclined wire mesh forming machine by a slurry pump to dehydrate and form a web to make a wet fiber layer; 3) Polyolefin elastic fibers are hot melt spun, crimped and laid into a network structure, and fed into a hot bonding equipment in a relaxed state for low-pressure hot melt bonding to form a network skeleton structure, providing an elastic body. The network skeleton structure is then wound into a roll of material. 4) The polyolefin elastic fiber roll is unwound and conveyed, and then stacked with the first wet-process ultra-short fiber layer. Because the polyolefin elastic fiber has elasticity and stickiness, the polyolefin elastic fiber layer is actively separated by an L-shaped peeling roller. 5) The two layers of material are overfed into the hydroentangled flat net support curtain, and the superimposed material is hydroentangled in four stages using a decreasing low-pressure hydroentanglement process, so that the ultra-short fibers penetrate into the gaps of the polyolefin elastic fiber network skeleton structure layer and form entanglement points with the polyolefin elastic fibers. 6) Remove moisture from the two hydroentangled layers by vacuum suction or rolling mill, collect them into rolls, unwind them a second time, and enter the composite conveyor curtain to overlap with the second layer of ultra-short fiber web. Under the action of secondary decreasing low-pressure hydroentangling, a three-layer structure is formed with ultra-short fibers in the upper and lower layers and polyolefin elastic fibers in the middle layer. 7) The three-layer structure material after hydroentangling is dehydrated by vacuum suction or roller drying, and then dried at low tension and temperature and rolled into rolls to produce an elastic wet hydroentangling nonwoven fabric with a unit area mass of 35-80g / ㎡ of ultra-short fiber composite polyolefin elastic fiber.

[0028] Preferably, in step 1), the fiber spreading device is equipped with two sets of rotating blades, one upper and one lower. Each set of rotating blades has two symmetrical blades with an angle of 8-10°. The upper blade has a blade thickness of 0.8-1.2 mm, and the lower blade has a blade thickness of 1.5-1.9 mm. The spreading concentration of the fiber suspension is 0.2-0.5%, and the spreading device rotates at 600-1000 r / min, with each spreading session lasting 9-10 minutes. In step 3), the polyolefin elastic fiber spinning and laying speed is 101-102% of the conveyor curtain speed, causing the polyolefin elastic fiber to flocculate into a curled state. The speed of the bonding roller in the thermal bonding device is lower than the feeding speed of the conveyor curtain to avoid stretching of the polyolefin elastic fiber and reducing its elasticity. The bonding roller in the thermal bonding device consists of a steel roller and a patterned roller. The surface of the patterned roller is covered with protrusions with a height of 0.4-0.6 mm, a width of 0.4-0.6 mm, and a spacing of 1.5-2.5 mm. The protrusions are rhomboid or elliptical in shape.

[0029] In step 4), the polyolefin elastic fiber unwinding process uses an L-shaped peeling roller to actively separate the polyolefin elastic fiber layer. The linear speed of the peeling roller is 100.3% to 100.5% of the speed of the composite conveyor curtain, so that after the modified polypropylene skeleton layer is actively peeled, it shrinks and rebounds to a relaxed state through speed difference overfeeding, and then overlaps with the first layer of ultra-short fiber layer. Step 5) employs a decreasing low-pressure hydroentangling process to perform four hydroentangling passes on the two-layered material. The pressure of the first hydroentangling pass is 30-35 bar, the pressure of the second hydroentangling pass is 28-32 bar, the pressure of the third hydroentangling pass is 26-30 bar, and the pressure of the fourth hydroentangling pass is 26 bar. This is combined with high negative pressure suction dehydration, which allows the upper layer of ultra-short fibers to interweave and entangle with the polyolefin elastic fibers. If the pressure of the first hydroentangling pass is too low, the ultra-short fibers will not displace sufficiently and will float on the surface of the material. Under the action of the second, third, and fourth hydroentangling passes, the ultra-short fibers will become entangled with each other on the surface of the material, resulting in a small overall elastic displacement space for the material. If the pressure of the first hydroentangling pass is too high, the upper layer of ultra-short fibers will penetrate the middle polyolefin elastic fiber network skeleton structure layer, resulting in a large loss of ultra-short fibers and affecting the yield.

[0030] The drying temperature in step 7) is 103-108°C. If the temperature is too high, it will cause melting damage to the polyolefin elastic fiber, thereby reducing the strength of the material. If the temperature is too low, the initial softening temperature of the polyolefin elastic fiber will not be reached, and the purpose of softening and shrinkage cannot be achieved. Only with a suitable temperature and low tension stretching can the material shrink further, thereby providing higher elasticity and softness.

[0031] The test data for this invention are shown in the table below: The design features of this invention are as follows: This invention achieves multi-dimensional elasticity upgrades and process innovation through a wet hydroentangling composite process of ultra-short fibers and polyolefin elastic fibers: 1) Breakthrough in all-directional elasticity: Through a three-dimensional mesh structure design, combined with longitudinal elongation at break of 180-200% (recovery rate of 97-99%), transverse elongation at break of 60-90% (recovery rate of 92-97%), and cross-directional elasticity, it achieves three-dimensional synergistic elasticity in the longitudinal, transverse, and cross directions, breaking through the limitations of traditional unidirectional elasticity. 2) Optimized elasticity efficiency: Ultra-short fibers (0.1-1.2 dtex, 3-6 mm) and polyolefin elastic fibers (25-60% by mass) form entanglement points through a decreasing low-pressure hydroentangling process (30-35 bar → 26 bar in four decreasing stages), combined with a three-dimensional network with a reinforcement spacing of 1.5-2.5 mm, achieving a composite of elastomer and fiber, resulting in more complete elastic performance; 3) Process innovation: Wet hydroentangling process is used to replace traditional spunbond / meltblown process. Combined with L-shaped peeling roller speed difference overfeed (100.3~100.5% speed matching) to achieve relaxed state lamination, and low tension fine temperature drying at 103~108℃ to avoid melt-breaking damage and improve elasticity and softness. 4) Performance balance: At a unit area mass of 35-80 g / m², the mass ratio of polyolefin elastic fiber to ultra-short fiber (25-60%: 40-75%) is optimized to balance elastic recovery rate and material strength, while avoiding fiber loss and improving the production yield. 5) Application expansion: Suitable for high-elasticity demand scenarios (such as medical materials, beauty products, hygiene products, flexible packaging), it maximizes the deformation space through three-dimensional elastic network to meet complex deformation requirements.

[0032] This invention, through innovation in three dimensions—process, structure, and performance—solves problems such as the single elastic direction of existing elastic nonwoven fabrics, coarse composite structures, insufficient elastic efficiency, damage to the transport of polyolefin elastic fiber filaments, and decreased elasticity of composites of ultra-short fibers and polyolefin elastic fibers. It achieves a dual improvement in elasticity and process efficiency. Utilizing this invention, the material's elasticity is maximized, and the curly, plush-like free fiber web can hold more essence and release liquid quickly. When used as a face mask, it extends the skin-adhering time and maximizes the efficacy of the essence.

[0033] The product prepared by this invention uses polyolefin elastic fiber filaments as the skeleton structure, combined with ultra-short fibers such as cellulose fibers and polyester fibers. While maintaining good moisture absorption, breathability and softness, it achieves longitudinal and transverse tensile elasticity of the material. When applied to beauty mask materials, the elastic application can not only lift and tighten the skin and maintain the elasticity of the material to the maximum extent, but the curly and fluffy free fiber network can also carry more essence and release the liquid quickly. When used as a mask, it can prolong the skin contact time, exert greater efficacy of the essence, and is more conducive to the pressurized absorption of the essence.

[0034] The specific embodiments described herein are merely illustrative of the principles and effects of the invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in this invention should still be covered by the claims of this invention.

Claims

1. An elastic wet-laid spunlace nonwoven fabric composed of ultra-short fiber composite polyolefin elastic fiber, characterized in that, The elastic wet-spunlace nonwoven fabric is made of short fibers and polyolefin elastic fibers using a wet-spunlace process. The polyolefin elastic fibers are thermally melt-spun and thermally bonded to form a relaxed three-dimensional network structure. The short fibers are selected from one or a combination of cellulose fibers and polyester fibers, and are arranged into a three-dimensional network structure by wet-spun web formation, so that the prepared elastic wet-spunlace nonwoven fabric has all-directional elasticity in the longitudinal, transverse and cross directions.

2. The elastic wet-laid spunlace nonwoven fabric of ultra-short fiber composite polyolefin elastic fiber according to claim 1, characterized in that, The polyolefin elastic fiber has a mass percentage of 25% to 60%, the ultra-short fiber has a mass percentage of 40% to 75%, and the unit area mass of the elastic wet-laid spunlace nonwoven fabric is 35 to 80 g / m².

3. The elastic wet-laid spunlace nonwoven fabric of ultra-short fiber composite polyolefin elastic fiber according to claim 1, characterized in that, The elastic wet-laid spunlace nonwoven fabric has a longitudinal tensile elongation at break of 180-200%, a length recovery rate of 97-99% when stretched to 100% elongation, a transverse tensile elongation at break of 60-90%, and a length recovery rate of 92-97% when stretched to 70% elongation.

4. The elastic wet-laid spunlace nonwoven fabric of ultra-short fiber composite polyolefin elastic fiber according to claim 1, characterized in that, The ultrashort fibers have a fineness of 0.1–1.2 dtex and a length of 3–6 mm.

5. The elastic wet-laid spunlace nonwoven fabric of ultra-short fiber composite polyolefin elastic fiber according to claim 1, characterized in that, The spacing between reinforcement points in the three-dimensional mesh structure is 1.5–2.5 mm, and the area of ​​each reinforcement point is 0.20–0.36 mm². 2 .

6. A method for preparing an elastic wet-laid spunlace nonwoven fabric, characterized in that, Includes the following steps: 1) The short fibers are pre-dispersed in a fiber dispersion device to ensure that the fibers in the fiber suspension are evenly dispersed in the water; 2) The fiber suspension is diluted and then fed into the inclined wire mesh forming machine by a slurry pump to dehydrate and form a web to make a wet fiber layer; 3) Polyolefin elastic fibers are hot melt spun, crimped and laid into a network structure, and fed into a hot bonding equipment in a relaxed state for low-pressure hot melt bonding to form a network skeleton structure, providing an elastic body. The network skeleton structure is then wound into a roll of material. 4) The polyolefin elastic fiber roll is unwound and conveyed, and then stacked with the first wet-process ultra-short fiber layer. Because the polyolefin elastic fiber has elasticity and stickiness, the polyolefin elastic fiber layer is actively separated by an L-shaped peeling roller. 5) The two layers of material are overfed into the hydroentangled flat net support curtain, and the superimposed material is hydroentangled in four stages using a decreasing low-pressure hydroentanglement process, so that the ultra-short fibers penetrate into the gaps of the polyolefin elastic fiber network skeleton structure layer and form entanglement points with the polyolefin elastic fibers. 6) Remove moisture from the two hydroentangled layers by vacuum suction or rolling mill, collect them into rolls, unwind them a second time, and enter the composite conveyor curtain to overlap with the second layer of ultra-short fiber web. Under the action of secondary decreasing low-pressure hydroentangling, a three-layer structure is formed with ultra-short fibers in the upper and lower layers and polyolefin elastic fibers in the middle layer. 7) The three-layer structure material after hydroentangling is dehydrated by vacuum suction or roller drying, and then dried at low tension and temperature and rolled into rolls to produce an elastic wet hydroentangling nonwoven fabric with a unit area mass of 35-80g / ㎡ of ultra-short fiber composite polyolefin elastic fiber.

7. The preparation method according to claim 6, characterized in that, In step 1), the fiber dispersing device is equipped with two sets of rotating blades, one above the other. Each set of rotating blades has two symmetrical blades with an angle of 8-10°. The upper blade has a blade toughness thickness of 0.8-1.2 mm, and the lower blade has a blade toughness thickness of 1.5-1.9 mm. The fiber suspension dispersing concentration is 0.2-0.5%. The dispersing device rotates at 600-1000 r / min, and each dispersing session lasts 9-10 minutes. In step (3), the polyolefin elastic fiber spinning and laying speed is 101-102% of the conveying speed of the conveyor curtain, so that the polyolefin elastic fiber is flocculated into a curled state. The speed of the bonding roller of the thermal bonding device is less than the feeding speed of the conveyor curtain to avoid stretching of the polyolefin elastic fiber and reducing its elasticity. The bonding roller of the thermal bonding device consists of a steel roller and a patterned roller. The surface of the patterned roller is distributed with protrusions of 0.4-0.6 mm in height, 0.4-0.6 mm in width, and 1.5-2.5 mm in spacing. The protrusions are rhomboid or elliptical in shape.

8. The preparation method according to claim 6, characterized in that, In step (4), the polyolefin elastic fiber unwinding adopts an L-shaped peeling roller to actively separate the polyolefin elastic fiber layer. The linear speed of the peeling roller is 100.3% to 100.5% of the speed of the composite conveyor curtain, so that after the modified polypropylene skeleton layer is actively peeled, it shrinks and rebounds to a relaxed state through speed difference overfeeding and overlaps with the first layer of ultra-short fiber layer.

9. The preparation method according to claim 6, characterized in that, In step (5), a decreasing low-pressure hydroentangling process is used to perform four hydroentangling processes on the two-layer composite material. The pressure of the first hydroentangling is 30-35 bar, the pressure of the second hydroentangling is 28-32 bar, the pressure of the third hydroentangling is 26-30 bar, and the pressure of the fourth hydroentangling is 26 bar. Simultaneously, high negative pressure suction dehydration is used to make the upper ultra-short fibers and polyolefin elastic fibers intertwine and entangle.

10. The preparation method according to claim 6, characterized in that, The drying temperature in step (7) is 103-108°C, which is used to cooperate with low-tension stretching to allow the material to shrink further, thereby providing higher elasticity and softness.

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