A method for preparing dry acrylic staple fiber nonwoven fabric

Abstract

The application discloses a kind of preparation methods of dry process acrylic staple fiber nonwoven fabric, comprising the following steps: S1 polymer including polyacrylonitrile is prepared into spinning solution with solvent, and primary fiber is spun using dry process with nitrogen as exchange medium;S2 primary fiber is washed, drawn, curled, oiled, cut, and dry process acrylic staple fiber is prepared by drying;S3 staple fiber is first opened mixed and carded into web, and is made into fluffy web according to random arrangement, and then is made into dry process acrylic staple fiber nonwoven fabric by mechanical puncture reinforcement.The dry process acrylic staple fiber is first opened mixed and carded into web, and is made into fluffy web according to random arrangement, and then is made into nonwoven fabric product with higher porosity in horizontal and vertical directions and uniform pore size distribution, good water absorption and water permeability, high strength, strong deformation resistance, soft texture and relatively fluffy structure, which meets the needs of downstream customer industrial environment.

Description

Technical Field

[0001] This invention relates to the field of dry-laid acrylic staple fiber nonwoven fabric technology, specifically to a method for preparing dry-laid acrylic staple fiber nonwoven fabric. Background Technology

[0002] Dry-spun acrylic fibers are high in strength and exhibit excellent resistance to aging, sunlight, acids, alkalis, and corrosion. The addition of customer-specified special materials further enhances their properties, including anti-pilling, antibacterial, absorbent, and recyclable characteristics. Dry-spun acrylic staple fiber nonwoven fabric is a nonwoven fabric produced using dry spinning technology. This material is primarily made of acrylic staple fibers, which are characterized by their dense structure, uniform internal structure, and vibrant dyeing, making them mainly used in clothing. The unique forming mechanism of dry-spun acrylic staple fibers results in a dog-bone cross-section. This structure makes the performance of dry-spun acrylic fibers significantly superior to wet-spun acrylic fibers, more closely resembling wool. Its characteristics include a large coverage area, elegant luster, uniform dyeing, and good heat and moisture properties.

[0003] However, during the manufacturing process of dry-spun acrylic staple fiber nonwoven fabric, the dry-spun acrylic staple fibers easily curl into irregularly shaped clumps. Therefore, subsequent forming and processing are required to produce industrial products with a certain length, width, and thickness, easy to use, and possessing a uniform and dense structure and excellent hydraulic properties to meet the needs of downstream customers in industrial environments such as drainage and filtration, and mining engineering. Therefore, it is necessary to improve the preparation method of dry-spun acrylic staple fiber nonwoven fabric according to the above requirements to obtain dry-spun acrylic staple fiber nonwoven fabric that meets the aforementioned performance requirements. Summary of the Invention

[0004] The technical problem to be solved by this invention is to overcome the shortcomings of the prior art and provide a method for preparing dry-laid acrylic staple fiber nonwoven fabric. The dry-laid acrylic staple fiber is first opened, mixed and carded into a web, and then randomly arranged to form a fluffy fiber web. It is then mechanically punctured and reinforced to produce a nonwoven fabric product with high porosity and uniform pore size distribution in both horizontal and vertical directions, good water absorption and permeability, high strength, strong resistance to deformation, soft texture and relatively fluffy structure, which meets the needs of downstream customers' industrial environment.

[0005] The technical solution of this invention is as follows:

[0006] A method for preparing a dry-laid acrylic staple fiber nonwoven fabric includes the following steps:

[0007] S1 prepares a spinning solution by combining a polymer including polyacrylonitrile with a solvent, and spins nascent fibers using a dry process with nitrogen as the exchange medium.

[0008] S2 nascent fibers are washed, stretched, crimped, oiled, cut, and dried to obtain dry-process acrylic staple fibers;

[0009] S3 short fibers are first opened, mixed, and carded into a web, then arranged randomly to form a fluffy fiber web, and finally reinforced by mechanical puncture to produce dry-laid acrylic short fiber nonwoven fabric.

[0010] Preferably, in step S1, the polyacrylonitrile is prepared by aqueous suspension method using acrylonitrile (AN) as monomer.

[0011] Preferably, in step S1, the solvent is dimethylacetamide (DMAC), dimethylformamide, or dimethyl sulfoxide.

[0012] Preferably, in step S1, the concentration of the spinning solution is 25-30 wt.%.

[0013] Preferably, in step S2, the nominal linear density of the short fiber is 1-2.78 dtex, and the nominal cut length is 28 mm or 32 mm.

[0014] Preferably, in step S2, to ensure that the fineness of the short fibers meets the conditions for preparing nonwoven fabric, the speed of the driving motor of the stretching machine during water washing is 700-850 rpm, and the exit linear speed of the stretching machine is 325-395 m / min.

[0015] Preferably, in step S3, during the opening process, the acrylic fibers in the fine clumps produced by excessive opening will become entangled due to static electricity, generating more fuzz. Therefore, in order to ensure that the fibers are fully opened without the presence of small clumps in the raw material due to repeated opening, a nail plate opening machine is used during opening, and the motor frequency of the opening cylinder is 35-45Hz. During mixing, in order to control the amount of cotton and the degree of fiber mixing, reduce the influence of static electricity on dry acrylic fibers, and ensure uniform density distribution of fibers in the transverse and longitudinal directions, the motor frequency of the corner curtain is controlled at 45-50Hz, so that the cotton can be fully mixed and extended in the cotton feeding machine.

[0016] Preferably, in step S3, during the carding process, the customized carding machine spacing is not adjustable. To ensure the reduction of dry acrylic fiber knot formation and to form a continuous and uniform cotton web, the frequency of the carding machine doffer motor is controlled at 15-20Hz. The reduced surface speed of the doffer motor allows the dry acrylic fibers to form a thicker fiber layer on its surface, making it easier to peel off.

[0017] Preferably, in step S3, during mechanical puncture reinforcement, the needle density is 100-150 needles / cm². 2 The needle insertion depth is 10-15mm.

[0018] Compared with the prior art, the present invention has the following advantages:

[0019] 1. The method for preparing dry-laid acrylic staple fiber nonwoven fabric of the present invention involves first opening, mixing, and carding the dry-laid acrylic staple fibers into a web, then randomly arranging them to form a loose fiber web, and finally mechanically puncturing and reinforcing it to produce a nonwoven fabric product with high porosity and uniform pore size distribution in both horizontal and vertical directions, good water absorption and permeability, high strength, strong resistance to deformation, soft texture, and relatively loose structure. This method optimizes the performance of dry-laid acrylic staple fiber products, enriches the variety of dry-laid acrylic products, improves the competitiveness of the acrylic product industry, and meets the needs of downstream customers' industrial environments.

[0020] 2. The nonwoven fabric prepared by this invention exhibits significant volume change, which is beneficial for warehouse management, correspondingly reducing the warehouse area occupied, while also alleviating the labor intensity of operators and reducing the consumption of packaging materials. Detailed Implementation

[0021] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of this invention will be clearly and completely described below in conjunction with the embodiments of this invention.

[0022] Example 1

[0023] This embodiment provides a method for preparing dry-laid acrylic staple fiber nonwoven fabric, including the following steps:

[0024] S1 spun nascent fiber

[0025] Using acrylonitrile (AN) as the first monomer and methyl acrylate as the second monomer, a polymer was produced by aqueous suspension polymerization. The specific process is as follows: A mixed monomer solution (prepared by mixing the first monomer, second monomer, sulfur dioxide, and recovered monomer in a static mixer at a mass ratio of 4000:500:40:450) from the raw material supply tank, after passing through a mixer cooler, is metered into the polymerization reactor along with the catalyst potassium persulfate and the terminator disodium ethylenediaminetetraacetate. Simultaneously, the neutralizing agent NaOH enters the activation tower, where it reacts with SO2 to generate NaHSO3, which then enters the polymerization reactor to participate in the reaction. The components are thoroughly mixed using an in-reactor stirrer (stirrer speed 150 rpm), with continuous feeding, reaction, and discharge. The polymerization reaction is exothermic, and chilled water (7°C) must be used as a jacket cooling medium to remove the heat of reaction and maintain the reaction temperature at 62°C.

[0026] The prepared polymer was mixed with the solvent dimethylacetamide to form a 30 wt.% spinning solution. The nascent fibers were spun using a dry process with nitrogen as the exchange medium. The specific process is as follows: The qualified spinning solution from the spinning solution preparation area was filtered and then pumped to the spinning solution manifold of the spinning machine. It was squeezed through the spinneret and entered each spinning channel. The solvent was extracted by high-temperature nitrogen to solidify the fiber bundle and merge it with the fiber bundles from other channels. The denier of the fiber bundle was controlled by the traction feeder. Then it was sent from the channel to the nascent fiber bundle holding tank.

[0027] S2 Preparation of Dry-Process Acrylic Short Fibers

[0028] Nascent fibers are processed through washing, drawing, crimping, oiling, cutting, and drying to obtain dry-spun acrylic staple fibers with a nominal linear density of 2.78 dtex and a nominal cut length of 28 mm. The washing process removes and recycles solvents from the nascent fibers; drawing stretches the polymer macromolecules and aligns them along the direction of force; crimping the fibers gives the filament bundles a certain cohesive force, achieving the physical properties required for textile fibers; oiling lubricates the fibers and increases their cohesive force; cutting shortens the filaments to meet product processing requirements; and drying, under high temperature and relaxation conditions, above the glass transition temperature and with the swelling effect of water, intensifies the macromolecular movement of the fibers, thereby eliminating intermolecular stress, strengthening the fiber structure, and further improving the fiber's spinnability.

[0029] Furthermore, during washing, the speed of the drafting machine drive motor is 700 rpm, and the exit linear velocity of the drafting machine is 325 m / min. The crimping motor is controlled by the same control device that controls the main motor of the washing drafting machine, and its speed changes in 5% increments with the main motor of the washing drafting machine, thus ensuring that the ribbon between the drafting roller and the crimping machine is taut. The oiling roller is directly connected to a variable speed motor, and its speed is set to a minimum of 10 rpm to reduce the static electricity effect of the oil on the nonwoven fabric. During drying, heat setting is performed in the dryer at approximately 130°C under 0.55 MPa steam.

[0030] S3 Preparation of Dry-Spun Acrylic Short Fiber Nonwoven Fabric

[0031] Short fibers are first opened, mixed, and carded into a web, arranged randomly to form a loose fiber web, and then mechanically punctured and reinforced to produce dry-laid acrylic short fiber nonwoven fabric. Appropriate opening and mixing allows the short fibers to form a uniform tuft, reducing the formation of knots; carding processes the fibers after the opening and cleaning process into a thin fiber web, which is then laid out and cross-laid before being reinforced by a needle punch to form the nonwoven fabric.

[0032] The process includes using a nail-plate opening machine during the opening process, with the motor frequency of the cylinder opening machine at 35Hz; using a 45Hz motor during the mixing process; using a 15Hz motor for the carding machine doffer; and using a needle-punching density of 100 needles / cm² during mechanical piercing reinforcement. 2 The needle insertion depth is 10mm.

[0033] The nonwoven fabric prepared in this embodiment has a bursting strength of 524.89 N, a longitudinal tear strength of 355 N, a vertical water permeability coefficient of 0.398 cm / s, an average thickness of 3.24 mm, and a variance of 0.0144 mm. 2 .

[0034] Example 2

[0035] This embodiment provides a method for preparing dry-laid acrylic staple fiber nonwoven fabric, including the following steps:

[0036] S1 spun nascent fiber

[0037] The polymer was prepared by aqueous suspension method using acrylonitrile (AN) as the first monomer and methyl acrylate as the second monomer, and the specific process was the same as in Example 1.

[0038] The prepared polymer was mixed with the solvent dimethylacetamide to form a 30 wt.% spinning solution. The nascent fibers were spun using a dry process with nitrogen as the exchange medium. The specific preparation process was the same as in Example 1.

[0039] S2 Preparation of Dry-Process Acrylic Short Fibers

[0040] Nascent fibers are washed, drawn, crimped, oiled, cut, and dried to obtain dry-laid acrylic staple fibers with a nominal linear density of 2.78 dtex and a nominal cut length of 28 mm. During washing, the drawing machine drive motor rotates at 700 rpm, and the drawing machine exit linear velocity is 325 m / min. The crimping motor is controlled by the same control device that controls the main washing and drawing motor; its speed changes in 5% increments with the main washing and drawing motor, ensuring the ribbon between the drawing roller and the crimping machine is taut. The oiling roller is directly connected to a variable-speed motor; to reduce the static electricity effect of the oil on the nonwoven fabric, its speed is set to a minimum of 10 rpm. Heat setting is performed in a dryer at approximately 130°C under 0.55 MPa steam.

[0041] S3 Preparation of Dry-Spun Acrylic Short Fiber Nonwoven Fabric

[0042] Short fibers are first opened, mixed, and carded into a web, arranged randomly to form a loose fiber web, and then mechanically punctured and reinforced to produce dry-laid acrylic short fiber nonwoven fabric. Appropriate opening and mixing allows the short fibers to form a uniform tuft, reducing the formation of knots; carding processes the fibers after the opening and cleaning process into a thin fiber web, which is then laid out and cross-laid before being reinforced by a needle punch to form the nonwoven fabric.

[0043] The process includes using a nail-plate opening machine during the opening process, with the motor frequency of the cylinder opening machine at 35Hz; using a 45Hz motor during the mixing process; using a 15Hz motor for the carding machine doffer; and using a needle-punching density of 100 needles / cm² during mechanical piercing reinforcement. 2 The needle insertion depth is 10mm.

[0044] The nonwoven fabric prepared in this embodiment has a bursting strength of 505.88 N, a longitudinal tear strength of 382 N, a vertical water permeability coefficient of 0.421 cm / s, an average thickness of 3.57 mm, and a variance of 0.0211 mm. 2 .

[0045] Example 3

[0046] This embodiment provides a method for preparing dry-laid acrylic staple fiber nonwoven fabric, including the following steps:

[0047] S1 spun nascent fiber

[0048] The polymer was prepared by aqueous suspension method using acrylonitrile (AN) as the first monomer and methyl acrylate as the second monomer, and the specific process was the same as in Example 1.

[0049] The prepared polymer was mixed with the solvent dimethylacetamide to form a 30 wt.% spinning solution. The nascent fibers were spun using a dry process with nitrogen as the exchange medium. The specific preparation process was the same as in Example 1.

[0050] S2 Preparation of Dry-Process Acrylic Short Fibers

[0051] Nascent fibers are washed, drawn, crimped, oiled, cut, and dried to obtain dry-laid acrylic staple fibers with a nominal linear density of 2.78 dtex and a nominal cut length of 32 mm. During washing, the drawing machine drive motor rotates at 700 rpm, and the drawing machine exit linear velocity is 325 m / min. The crimping motor is controlled by the same control device that controls the main washing and drawing motor; its speed changes in 5% increments with the main washing and drawing motor, ensuring the ribbon between the drawing roller and the crimping machine is taut. The oiling roller is directly connected to a variable-speed motor; to reduce the static electricity effect of the oil on the nonwoven fabric, its speed is set to a minimum of 10 rpm. Heat setting is performed in a dryer at approximately 130°C under 0.55 MPa steam.

[0052] S3 Preparation of Dry-Spun Acrylic Short Fiber Nonwoven Fabric

[0053] Short fibers are first opened, mixed, and carded into a web, arranged randomly to form a loose fiber web, and then mechanically punctured and reinforced to produce dry-laid acrylic short fiber nonwoven fabric. Appropriate opening and mixing allows the short fibers to form a uniform tuft, reducing the formation of knots; carding processes the fibers after the opening and cleaning process into a thin fiber web, which is then laid out and cross-laid before being reinforced by a needle punch to form the nonwoven fabric.

[0054] The process includes using a nail-plate opening machine during the opening phase, with the motor frequency of the cylinder opening machine at 40Hz; using a 45Hz motor during the mixing phase; using a 20Hz doffer motor for the carding machine; and a needle-punching density of 100 needles / cm² during mechanical piercing reinforcement. 2 The needle insertion depth is 10mm.

[0055] The nonwoven fabric prepared in this embodiment has a bursting strength of 498.25 N, a longitudinal tear strength of 374 N, a vertical water permeability coefficient of 0.382 cm / s, an average thickness of 3.41 mm, and a variance of 0.0185 mm. 2 .

[0056] Example 4

[0057] This embodiment provides a method for preparing dry-laid acrylic staple fiber nonwoven fabric, including the following steps:

[0058] S1 spun nascent fiber

[0059] Using acrylonitrile (AN) as the first monomer and methyl acrylate as the second monomer, a polymer was produced by aqueous suspension polymerization. The specific process is as follows: A mixed monomer solution (prepared by mixing the first monomer, second monomer, sulfur dioxide, and recovered monomer in a static mixer at a mass ratio of 4000:500:40:450) from the raw material supply tank, after passing through a mixer cooler, is metered into the polymerization reactor along with the catalyst potassium persulfate and the terminator disodium ethylenediaminetetraacetate. Simultaneously, the neutralizing agent NaOH enters the activation tower, where it reacts with SO2 to generate NaHSO3, which then enters the polymerization reactor to participate in the reaction. The components are thoroughly mixed using an in-reactor stirrer (stirrer speed 150 rpm), with continuous feeding, reaction, and discharge. The polymerization reaction is exothermic, and chilled water (chilled water temperature 6℃) must be used as a jacket cooling medium to remove the heat of reaction and maintain the reaction temperature at 60℃.

[0060] The polymer and solvent dimethylacetamide were mixed to form a 30 wt.% spinning solution. Nascent fibers were spun using a dry process with nitrogen as the exchange medium. The specific preparation process was the same as in Example 1.

[0061] S2 Preparation of Dry-Process Acrylic Short Fibers

[0062] Nascent fibers are washed, drawn, crimped, oiled, cut, and dried to obtain dry-laid acrylic staple fibers with a nominal linear density of 1 dtex and a nominal cut length of 32 mm. During washing, the drawing machine drive motor rotates at 700 rpm, and the drawing machine exit linear velocity is 325 m / min. The crimping motor is controlled by the same control device that controls the main washing and drawing motor; its speed changes in 5% increments with the main washing and drawing motor, ensuring the ribbon between the drawing roller and the crimping machine is taut. The oiling roller is directly connected to a variable-speed motor; to reduce the static electricity effect of the oil on the nonwoven fabric, its speed is set to a minimum of 10 rpm. Heat setting is performed in a dryer at approximately 130°C under 0.55 MPa steam.

[0063] S3 Preparation of Dry-Spun Acrylic Short Fiber Nonwoven Fabric

[0064] Short fibers are first opened, mixed, and carded into a web, arranged randomly to form a loose fiber web, and then mechanically punctured and reinforced to produce dry-laid acrylic short fiber nonwoven fabric. Appropriate opening and mixing allows the short fibers to form a uniform tuft, reducing the formation of knots; carding processes the fibers after the opening and cleaning process into a thin fiber web, which is then laid out and cross-laid before being reinforced by a needle punch to form the nonwoven fabric.

[0065] The process includes using a nail-plate opening machine during the opening process, with the motor frequency of the cylinder opening machine at 35Hz; using a 45Hz motor during the mixing process; using a 15Hz motor for the carding machine doffer; and using a needle-punching density of 100 needles / cm² during mechanical piercing reinforcement. 2 The needle insertion depth is 10mm.

[0066] The nonwoven fabric prepared in this embodiment has a bursting strength of 522.54 N, a longitudinal tear strength of 381 N, a vertical water permeability coefficient of 0.346 cm / s, an average thickness of 3.82 mm, and a variance of 0.0341 mm. 2 .

[0067] Example 5

[0068] This embodiment provides a method for preparing dry-laid acrylic staple fiber nonwoven fabric, including the following steps:

[0069] S1 spun nascent fiber

[0070] Using acrylonitrile (AN) as the first monomer and methyl acrylate as the second monomer, a polymer was produced by aqueous suspension polymerization. The specific process is as follows: A mixed monomer solution (prepared by mixing the first monomer, second monomer, sulfur dioxide, and recovered monomer in a static mixer at a mass ratio of 4000:500:40:450) from the raw material supply tank, after passing through a mixer cooler, is metered into the polymerization reactor along with the catalyst potassium persulfate and the terminator disodium ethylenediaminetetraacetate. Simultaneously, the neutralizing agent NaOH enters the activation tower, where it reacts with SO2 to generate NaHSO3, which then enters the polymerization reactor to participate in the reaction. The components are thoroughly mixed using an in-reactor stirrer (stirrer speed 150 rpm), with continuous feeding, reaction, and discharge. The polymerization reaction is exothermic, and chilled water (7°C) must be used as a jacket cooling medium to remove the heat of reaction and maintain the reaction temperature at 60°C.

[0071] The polymer and solvent dimethylacetamide were mixed to form a spinning solution of 28 wt.%, and nascent fibers were spun using a dry process with nitrogen as the exchange medium. The specific preparation process was the same as in Example 1.

[0072] S2 Preparation of Dry-Process Acrylic Short Fibers

[0073] Nascent fibers are washed, drawn, crimped, oiled, cut, and dried to obtain dry-laid acrylic staple fibers with a nominal linear density of 2.78 dtex and a nominal cut length of 28 mm. During washing, the drawing machine drive motor rotates at 850 rpm, and the drawing machine exit linear velocity is 395 m / min. The crimping motor is controlled by the same control device that controls the main washing and drawing motor; its speed changes in 5% increments with the main washing and drawing motor, ensuring the ribbon between the drawing roller and the crimping machine is taut. The oiling roller is directly connected to a variable-speed motor; to reduce the static electricity effect of the oil on the nonwoven fabric, its speed is set to a minimum of 10 rpm. Heat setting is performed in a dryer at approximately 130°C under 0.55 MPa steam.

[0074] S3 Preparation of Dry-Spun Acrylic Short Fiber Nonwoven Fabric

[0075] Short fibers are first opened, mixed, and carded into a web, arranged randomly to form a loose fiber web, and then mechanically punctured and reinforced to produce dry-laid acrylic short fiber nonwoven fabric. Appropriate opening and mixing allows the short fibers to form a uniform tuft, reducing the formation of knots; carding processes the fibers after the opening and cleaning process into a thin fiber web, which is then laid out and cross-laid before being reinforced by a needle punch to form the nonwoven fabric.

[0076] The process includes using a nail-plate opening machine during the opening process, with the motor frequency of the cylinder opening machine at 35Hz; using a 45Hz motor during the mixing process; using a 15Hz motor for the carding machine doffer; and using a needle-punching density of 100 needles / cm² during mechanical piercing reinforcement. 2The needle insertion depth is 10mm.

[0077] The nonwoven fabric prepared in this embodiment has a bursting strength of 504.57 N, a longitudinal tear strength of 356 N, a vertical water permeability coefficient of 0.391 cm / s, an average thickness of 3.26 mm, and a variance of 0.0124 mm. 2 .

[0078] Example 6

[0079] This embodiment provides a method for preparing dry-laid acrylic staple fiber nonwoven fabric, including the following steps:

[0080] S1 spun nascent fiber

[0081] Using acrylonitrile (AN) as the first monomer and methyl acrylate as the second monomer, a polymer was produced by aqueous suspension polymerization. The specific process is as follows: A mixed monomer solution (prepared by mixing the first monomer, second monomer, sulfur dioxide, and recovered monomer in a static mixer at a mass ratio of 4000:500:40:450) from the raw material supply tank, after passing through a mixer cooler, is metered into the polymerization reactor along with the catalyst potassium persulfate and the terminator disodium ethylenediaminetetraacetate. Simultaneously, the neutralizing agent NaOH enters the activation tower, where it reacts with SO2 to generate NaHSO3, which then enters the polymerization reactor to participate in the reaction. The components are thoroughly mixed using an in-reactor stirrer (stirrer speed 150 rpm), with continuous feeding, reaction, and discharge. The polymerization reaction is exothermic, and chilled water (chilled water temperature 5℃) must be used as a jacket cooling medium to remove the heat of reaction and maintain the reaction temperature at 61℃.

[0082] The polymer and solvent dimethylacetamide were mixed to form a 30 wt.% spinning solution. Nascent fibers were spun using a dry process with nitrogen as the exchange medium. The specific preparation process was the same as in Example 1.

[0083] S2 Preparation of Dry-Process Acrylic Short Fibers

[0084] Nascent fibers are washed, drawn, crimped, oiled, cut, and dried to obtain dry-laid acrylic staple fibers with a nominal linear density of 1 dtex and a nominal cut length of 32 mm. During washing, the drawing machine drive motor rotates at 700 rpm, and the drawing machine exit linear velocity is 325 m / min. The crimping motor is controlled by the same control device that controls the main washing and drawing motor; its speed changes in 5% increments with the main washing and drawing motor, ensuring the ribbon between the drawing roller and the crimping machine is taut. The oiling roller is directly connected to a variable-speed motor; to reduce the static electricity effect of the oil on the nonwoven fabric, its speed is set to a minimum of 10 rpm. Heat setting is performed in a dryer at approximately 130°C under 0.55 MPa steam.

[0085] S3 Preparation of Dry-Spun Acrylic Short Fiber Nonwoven Fabric

[0086] Short fibers are first opened, mixed, and carded into a web, arranged randomly to form a loose fiber web, and then mechanically punctured and reinforced to produce dry-laid acrylic short fiber nonwoven fabric. Appropriate opening and mixing allows the short fibers to form a uniform tuft, reducing the formation of knots; carding processes the fibers after the opening and cleaning process into a thin fiber web, which is then laid out and cross-laid before being reinforced by a needle punch to form the nonwoven fabric.

[0087] The process includes using a nail-plate opening machine during the opening phase, with the motor frequency of the cylinder opening machine at 35Hz; using a 50Hz motor during the mixing phase; using a 15Hz motor for the carding machine doffer; and a needle-punching density of 150 needles / cm² during mechanical piercing reinforcement. 2 The needle insertion depth is 15mm.

[0088] The nonwoven fabric prepared in this embodiment has a bursting strength of 517.56 N, a longitudinal tear strength of 381 N, a vertical water permeability coefficient of 0.305 cm / s, an average thickness of 3.15 mm, and a variance of 0.0344 mm. 2 .

[0089] Example 7

[0090] This embodiment provides a method for preparing dry-laid acrylic staple fiber nonwoven fabric, including the following steps:

[0091] S1 spun nascent fiber

[0092] Using acrylonitrile (AN) as the first monomer and methyl acrylate as the second monomer, a polymer was produced by aqueous suspension polymerization. The specific process is as follows: A mixed monomer solution (prepared by mixing the first monomer, second monomer, sulfur dioxide, and recovered monomer in a static mixer at a mass ratio of 4000:500:40:450) from the raw material supply tank, after passing through a mixer cooler, is metered into the polymerization reactor along with the catalyst potassium persulfate and the terminator disodium ethylenediaminetetraacetate. Simultaneously, the neutralizing agent NaOH enters the activation tower, where it reacts with SO2 to generate NaHSO3, which then enters the polymerization reactor to participate in the reaction. The components are thoroughly mixed using an in-reactor stirrer (stirrer speed 150 rpm), with continuous feeding, reaction, and discharge. The polymerization reaction is exothermic, and chilled water (chilled water temperature 5℃) must be used as a jacket cooling medium to remove the heat of reaction and maintain the reaction temperature at 60℃.

[0093] The polymer and solvent dimethylacetamide were mixed to form a spinning solution of 25 wt.%, and nascent fibers were spun using a dry process with nitrogen as the exchange medium. The specific preparation process was the same as in Example 1.

[0094] S2 Preparation of Dry-Process Acrylic Short Fibers

[0095] Nascent fibers are washed, drawn, crimped, oiled, cut, and dried to obtain dry-laid acrylic staple fibers with a nominal linear density of 2.78 dtex and a nominal cut length of 28 mm. During washing, the drawing machine drive motor rotates at 700 rpm, and the drawing machine exit linear velocity is 325 m / min. The crimping motor is controlled by the same control device that controls the main washing and drawing motor; its speed changes in 5% increments with the main washing and drawing motor, ensuring the ribbon between the drawing roller and the crimping machine is taut. The oiling roller is directly connected to a variable-speed motor; to reduce the static electricity effect of the oil on the nonwoven fabric, its speed is set to a minimum of 10 rpm. Heat setting is performed in a dryer at approximately 130°C under 0.55 MPa steam.

[0096] S3 Preparation of Dry-Spun Acrylic Short Fiber Nonwoven Fabric

[0097] Short fibers are first opened, mixed, and carded into a web, arranged randomly to form a loose fiber web, and then mechanically punctured and reinforced to produce dry-laid acrylic short fiber nonwoven fabric. Appropriate opening and mixing allows the short fibers to form a uniform tuft, reducing the formation of knots; carding processes the fibers after the opening and cleaning process into a thin fiber web, which is then laid out and cross-laid before being reinforced by a needle punch to form the nonwoven fabric.

[0098] The process includes using a nail-plate opening machine during opening, with the motor frequency of the cylinder opening machine at 40Hz; using a 45Hz motor during mixing; using a 15Hz doffer motor for the carding machine; and using a needle-punching density of 100 needles / cm² during mechanical piercing reinforcement. 2 The needle insertion depth is 10mm.

[0099] The nonwoven fabric prepared in this embodiment has a bursting strength of 551.52 N, a longitudinal tear strength of 304 N, a vertical water permeability coefficient of 0.351 cm / s, an average thickness of 3.05 mm, and a variance of 0.0255 mm. 2 .

[0100] Example 8

[0101] This embodiment provides a method for preparing dry-laid acrylic staple fiber nonwoven fabric, including the following steps:

[0102] S1 spun nascent fiber

[0103] The polymer was prepared by aqueous suspension method using acrylonitrile (AN) as the first monomer and methyl acrylate as the second monomer, and the specific process was the same as in Example 1.

[0104] The polymer and solvent dimethylacetamide were mixed to form a 30 wt.% spinning solution. Nascent fibers were spun using a dry process with nitrogen as the exchange medium. The specific preparation process was the same as in Example 1.

[0105] S2 Preparation of Dry-Process Acrylic Short Fibers

[0106] Nascent fibers are washed, drawn, crimped, oiled, cut, and dried to obtain dry-laid acrylic staple fibers with a nominal linear density of 2.78 dtex and a nominal cut length of 28 mm. During washing, the drawing machine drive motor rotates at 700 rpm, and the drawing machine exit linear velocity is 325 m / min. The crimping motor is controlled by the same control device that controls the main washing and drawing motor; its speed changes in 5% increments with the main washing and drawing motor, ensuring the ribbon between the drawing roller and the crimping machine is taut. The oiling roller is directly connected to a variable-speed motor; to reduce the static electricity effect of the oil on the nonwoven fabric, its speed is set to a minimum of 10 rpm. Heat setting is performed in a dryer at approximately 130°C under 0.55 MPa steam.

[0107] S3 Preparation of Dry-Spun Acrylic Short Fiber Nonwoven Fabric

[0108] Short fibers are first opened, mixed, and carded into a web, arranged randomly to form a loose fiber web, and then mechanically punctured and reinforced to produce dry-laid acrylic short fiber nonwoven fabric. Appropriate opening and mixing allows the short fibers to form a uniform tuft, reducing the formation of knots; carding processes the fibers after the opening and cleaning process into a thin fiber web, which is then laid out and cross-laid before being reinforced by a needle punch to form the nonwoven fabric.

[0109] The process includes using a nail-plate opening machine during the opening phase, with the motor frequency of the cylinder opening machine at 35Hz; using a 50Hz motor during the mixing phase; using a 15Hz motor for the carding machine doffer; and a needle-punching density of 100 needles / cm² during mechanical piercing reinforcement. 2 The needle insertion depth is 10mm.

[0110] The nonwoven fabric prepared in this embodiment has a bursting strength of 502.31 N, a longitudinal tear strength of 259 N, a vertical water permeability coefficient of 0.421 cm / s, an average thickness of 4.05 mm, and a variance of 0.0159 mm. 2 .

[0111] Example 9

[0112] This embodiment provides a method for preparing dry-laid acrylic staple fiber nonwoven fabric, including the following steps:

[0113] S1 spun nascent fiber

[0114] The polymer was prepared by aqueous suspension method using acrylonitrile (AN) as the first monomer and methyl acrylate as the second monomer, and the specific process was the same as in Example 1.

[0115] The prepared polymer was mixed with the solvent dimethylacetamide to form a 30 wt.% spinning solution. The nascent fibers were spun using a dry process with nitrogen as the exchange medium. The specific preparation process was the same as in Example 1.

[0116] S2 Preparation of Dry-Process Acrylic Short Fibers

[0117] Nascent fibers are washed, drawn, crimped, oiled, cut, and dried to obtain dry-laid acrylic staple fibers with a nominal linear density of 2.78 dtex and a nominal cut length of 28 mm. During washing, the drawing machine drive motor rotates at 700 rpm, and the drawing machine exit linear velocity is 325 m / min. The crimping motor is controlled by the same control device that controls the main washing and drawing motor; its speed changes in 5% increments with the main washing and drawing motor, ensuring the ribbon between the drawing roller and the crimping machine is taut. The oiling roller is directly connected to a variable-speed motor; to reduce the static electricity effect of the oil on the nonwoven fabric, its speed is set to a minimum of 10 rpm. Heat setting is performed in a dryer at approximately 130°C under 0.55 MPa steam.

[0118] S3 Preparation of Dry-Spun Acrylic Short Fiber Nonwoven Fabric

[0119] Short fibers are first opened, mixed, and carded into a web, arranged randomly to form a loose fiber web, and then mechanically punctured and reinforced to produce dry-laid acrylic short fiber nonwoven fabric. Appropriate opening and mixing allows the short fibers to form a uniform tuft, reducing the formation of knots; carding processes the fibers after the opening and cleaning process into a thin fiber web, which is then laid out and cross-laid before being reinforced by a needle punch to form the nonwoven fabric.

[0120] The process includes using a nail-plate opening machine during the opening phase, with the motor frequency of the cylinder opening machine at 40Hz; using a 45Hz motor during the mixing phase; using a 20Hz doffer motor for the carding machine; and a needle-punching density of 100 needles / cm² during mechanical piercing reinforcement. 2 The needle insertion depth is 10mm.

[0121] The nonwoven fabric prepared in this embodiment has a bursting strength of 504.52 N, a longitudinal tear strength of 364 N, a vertical water permeability coefficient of 0.307 cm / s, an average thickness of 3.51 mm, and a variance of 0.0251 mm. 2 .

[0122] Example 10

[0123] This embodiment provides a method for preparing dry-laid acrylic staple fiber nonwoven fabric, including the following steps:

[0124] S1 spun nascent fiber

[0125] Using acrylonitrile (AN) as the first monomer and methyl acrylate as the second monomer, a polymer was produced by aqueous suspension polymerization. The specific process is as follows: A mixed monomer solution (prepared by mixing the first monomer, second monomer, sulfur dioxide, and recovered monomer in a static mixer at a mass ratio of 4000:500:40:450) from the raw material supply tank, after passing through a mixer cooler, is metered into the polymerization reactor along with the catalyst potassium persulfate and the terminator disodium ethylenediaminetetraacetate. Simultaneously, the neutralizing agent NaOH enters the activation tower, where it reacts with SO2 to generate NaHSO3, which then enters the polymerization reactor to participate in the reaction. The components are thoroughly mixed using an in-reactor stirrer (stirrer speed 150 rpm), with continuous feeding, reaction, and discharge. The polymerization reaction is exothermic, and chilled water (chilled water temperature 6℃) must be used as a jacket cooling medium to remove the heat of reaction and maintain the reaction temperature at 61℃.

[0126] The polymer and solvent dimethylacetamide were mixed to form a spinning solution of 28 wt.%, and nascent fibers were spun using a dry process with nitrogen as the exchange medium. The specific preparation process was the same as in Example 1.

[0127] S2 Preparation of Dry-Process Acrylic Short Fibers

[0128] Nascent fibers are washed, drawn, crimped, oiled, cut, and dried to obtain dry-laid acrylic staple fibers with a nominal linear density of 2.78 dtex and a nominal cut length of 28 mm. During washing, the drawing machine drive motor rotates at 700 rpm, and the drawing machine exit linear velocity is 325 m / min. The crimping motor is controlled by the same control device that controls the main washing and drawing motor; its speed changes in 5% increments with the main washing and drawing motor, ensuring the ribbon between the drawing roller and the crimping machine is taut. The oiling roller is directly connected to a variable-speed motor; to reduce the static electricity effect of the oil on the nonwoven fabric, its speed is set to a minimum of 10 rpm. Heat setting is performed in a dryer at approximately 130°C under 0.55 MPa steam.

[0129] S3 Preparation of Dry-Spun Acrylic Short Fiber Nonwoven Fabric

[0130] Short fibers are first opened, mixed, and carded into a web, arranged randomly to form a loose fiber web, and then mechanically punctured and reinforced to produce dry-laid acrylic short fiber nonwoven fabric. Appropriate opening and mixing allows the short fibers to form a uniform tuft, reducing the formation of knots; carding processes the fibers after the opening and cleaning process into a thin fiber web, which is then laid out and cross-laid before being reinforced by a needle punch to form the nonwoven fabric.

[0131] The process includes using a nail-plate opening machine during the opening phase, with the motor frequency of the cylinder opening machine at 35Hz; using a 45Hz motor during the mixing phase; using a 15Hz doffer motor during the carding machine; and a needle-punching density of 150 needles / cm² during mechanical piercing reinforcement. 2The needle insertion depth is 10mm.

[0132] The nonwoven fabric prepared in this embodiment has a bursting strength of 454.52 N, a longitudinal tear strength of 361 N, a vertical water permeability coefficient of 0.358 cm / s, an average thickness of 3.41 mm, and a variance of 0.0351 mm. 2 .

[0133] Example 11

[0134] This embodiment provides a method for preparing dry-laid acrylic staple fiber nonwoven fabric, including the following steps:

[0135] S1 spun nascent fiber

[0136] Using acrylonitrile (AN) as the first monomer and methyl acrylate as the second monomer, a polymer was produced by aqueous suspension polymerization. The specific process is as follows: A mixed monomer solution (prepared by mixing the first monomer, second monomer, sulfur dioxide, and recovered monomer in a static mixer at a mass ratio of 4000:500:40:450) from the raw material supply tank, after passing through a mixer cooler, is metered into the polymerization reactor along with the catalyst potassium persulfate and the terminator disodium ethylenediaminetetraacetate. Simultaneously, the neutralizing agent NaOH enters the activation tower, where it reacts with SO2 to generate NaHSO3, which then enters the polymerization reactor to participate in the reaction. The components are thoroughly mixed using an in-reactor stirrer (stirrer speed 150 rpm), with continuous feeding, reaction, and discharge. The polymerization reaction is exothermic, and chilled water (7°C) must be used as a jacket cooling medium to remove the heat of reaction and maintain the reaction temperature at 60°C.

[0137] The prepared polymer was mixed with the solvent dimethylacetamide to form a 30 wt.% spinning solution. The nascent fibers were spun using a dry process with nitrogen as the exchange medium. The specific preparation process was the same as in Example 1.

[0138] S2 Preparation of Dry-Process Acrylic Short Fibers

[0139] Nascent fibers are washed, drawn, crimped, oiled, cut, and dried to obtain dry-laid acrylic staple fibers with a nominal linear density of 1 dtex and a nominal cut length of 32 mm. During washing, the drawing machine drive motor rotates at 700 rpm, and the drawing machine exit linear velocity is 325 m / min. The crimping motor is controlled by the same control device that controls the main washing and drawing motor; its speed changes in 5% increments with the main washing and drawing motor, ensuring the ribbon between the drawing roller and the crimping machine is taut. The oiling roller is directly connected to a variable-speed motor; to reduce the static electricity effect of the oil on the nonwoven fabric, its speed is set to a minimum of 10 rpm. Heat setting is performed in a dryer at approximately 130°C under 0.55 MPa steam.

[0140] S3 Preparation of Dry-Spun Acrylic Short Fiber Nonwoven Fabric

[0141] Short fibers are first opened, mixed, and carded into a web, arranged randomly to form a loose fiber web, and then mechanically punctured and reinforced to produce dry-laid acrylic short fiber nonwoven fabric. Appropriate opening and mixing allows the short fibers to form a uniform tuft, reducing the formation of knots; carding processes the fibers after the opening and cleaning process into a thin fiber web, which is then laid out and cross-laid before being reinforced by a needle punch to form the nonwoven fabric.

[0142] The process includes using a nail-plate opening machine during the opening process, with the motor frequency of the cylinder opening machine at 35Hz; using a 45Hz motor during the mixing process; using a 15Hz motor for the carding machine doffer; and using a needle-punching density of 100 needles / cm² during mechanical piercing reinforcement. 2 The needle insertion depth is 15mm.

[0143] The nonwoven fabric prepared in this embodiment has a bursting strength of 524.55 N, a longitudinal tear strength of 351 N, a vertical water permeability coefficient of 0.371 cm / s, an average thickness of 3.63 mm, and a variance of 0.0151 mm. 2 .

[0144] Example 12

[0145] This embodiment provides a method for preparing dry-laid acrylic staple fiber nonwoven fabric, including the following steps:

[0146] S1 spun nascent fiber

[0147] Using acrylonitrile (AN) as the first monomer and methyl acrylate as the second monomer, a polymer was produced by aqueous suspension polymerization. The specific process is as follows: A mixed monomer solution (prepared by mixing the first monomer, second monomer, sulfur dioxide, and recovered monomer in a static mixer at a mass ratio of 4000:500:40:450) from the raw material supply tank, after passing through a mixer cooler, is metered into the polymerization reactor along with the catalyst potassium persulfate and the terminator disodium ethylenediaminetetraacetate. Simultaneously, the neutralizing agent NaOH enters the activation tower, where it reacts with SO2 to generate NaHSO3, which then enters the polymerization reactor to participate in the reaction. The components are thoroughly mixed using an in-reactor stirrer (stirrer speed 150 rpm), with continuous feeding, reaction, and discharge. The polymerization reaction is exothermic, and chilled water (chilled water temperature 6℃) must be used as a jacket cooling medium to remove the heat of reaction and maintain the reaction temperature at 60℃.

[0148] The polymer and solvent dimethylacetamide were mixed to form a spinning solution of 29 wt.%, and nascent fibers were spun using a dry process with nitrogen as the exchange medium. The specific preparation process was the same as in Example 1.

[0149] S2 Preparation of Dry-Process Acrylic Short Fibers

[0150] Nascent fibers are washed, drawn, crimped, oiled, cut, and dried to obtain dry-laid acrylic staple fibers with a nominal linear density of 2.78 dtex and a nominal cut length of 28 mm. During washing, the drawing machine drive motor rotates at 700 rpm, and the drawing machine exit linear velocity is 325 m / min. The crimping motor is controlled by the same control device that controls the main washing and drawing motor; its speed changes in 5% increments with the main washing and drawing motor, ensuring the ribbon between the drawing roller and the crimping machine is taut. The oiling roller is directly connected to a variable-speed motor; to reduce the static electricity effect of the oil on the nonwoven fabric, its speed is set to a minimum of 10 rpm. Heat setting is performed in a dryer at approximately 130°C under 0.55 MPa steam.

[0151] S3 Preparation of Dry-Spun Acrylic Short Fiber Nonwoven Fabric

[0152] Short fibers are first opened, mixed, and carded into a web, arranged randomly to form a loose fiber web, and then mechanically punctured and reinforced to produce dry-laid acrylic short fiber nonwoven fabric. Appropriate opening and mixing allows the short fibers to form a uniform tuft, reducing the formation of knots; carding processes the fibers after the opening and cleaning process into a thin fiber web, which is then laid out and cross-laid before being reinforced by a needle punch to form the nonwoven fabric.

[0153] The process includes using a nail-plate opening machine during the opening phase, with the motor frequency of the cylinder opening machine at 35Hz; using a 50Hz motor during the mixing phase; using a 15Hz motor for the carding machine doffer; and a needle-punching density of 150 needles / cm² during mechanical piercing reinforcement. 2 The needle insertion depth is 15mm.

[0154] The nonwoven fabric prepared in this embodiment has a bursting strength of 516.58 N, a longitudinal tear strength of 351 N, a vertical water permeability coefficient of 0.378 cm / s, an average thickness of 3.65 mm, and a variance of 0.0079 mm. 2 .

[0155] Comparative Example 1

[0156] The difference from Example 1 is that in step S2, the speed of the stretching machine drive motor is 650 rpm and the machine exit line speed is 302 m / min during water washing.

[0157] Because the speed of the driving motor of the stretching machine was less than 700 rpm during washing, the stretching speed was too low, and the fibers prepared in the tunnel were not strong enough to be stretched and curled into a filament bundle with sufficient strength. The bursting strength of the final nonwoven fabric was 289.77 N, which was lower than the bursting strength of 524.89 N of the nonwoven fabric prepared in Example 1.

[0158] Comparative Example 2

[0159] The difference from Example 1 is that in step S2, the speed of the stretching machine drive motor is 900 rpm and the machine exit line speed is 445 m / min during water washing.

[0160] Because the speed of the drafting machine drive motor exceeds 850 rpm during washing, the excessively high speed of the drafting machine drive motor causes the oil roller in the same control circuit as the drafting machine to rotate too fast. During fiber opening, due to the high oil content in the fibers, electrostatic adsorption generates clumps, affecting the continuous and stable production of nonwoven fabric. Furthermore, the high oil content affects the water absorption and permeability of the nonwoven fabric. The vertical water permeability coefficient of the nonwoven fabric prepared in Comparative Example 2 is 0.355 cm / s, which is lower than the vertical water permeability coefficient of 0.398 cm / s of the nonwoven fabric prepared in Example 1.

[0161] Comparative Example 3

[0162] The difference from Example 1 is that in step S3, the motor frequency of the cylinder opening motor is 30Hz during opening and the motor frequency of the corner curtain motor is 40Hz during mixing.

[0163] The low motor frequency of the opening and mixing devices directly affected the stability of the nonwoven fabric thickness. The nonwoven fabric prepared in Comparative Example 3 had an average thickness of 3.51 mm and a variance of 0.676 mm. 2 The nonwoven fabric prepared in Example 1 had an average thickness of 3.24 mm and a variance of only 0.0144 mm. 2 .

[0164] Comparative Example 4

[0165] The difference from Example 1 is that in step S3, the motor frequency of the cylinder opening motor is 50Hz during opening and the motor frequency of the corner curtain motor is 55Hz during mixing.

[0166] Due to the excessively high frequency of the motor in the opening and mixing device, the raw materials were subjected to multiple and excessive opening and mixing processes, resulting in small clumps of fibers. These clumps then became entangled due to electrostatic effects, generating more fuzz and affecting the stable carding production of intermediate products, as well as the longitudinal tear strength of the nonwoven fabric. The longitudinal tear strength of the nonwoven fabric prepared in Comparative Example 4 was 281 N, lower than the 355 N of the nonwoven fabric prepared in Example 1.

[0167] Comparative Example 5

[0168] The difference from Example 1 is that in step S3, the frequency of the combing machine doffer motor is 10Hz.

[0169] Due to the low frequency of the carding doffer motor, the carding effect was poor, failing to effectively reduce the formation of neps, and the uniformity of the cotton web was affected. The average thickness of the nonwoven fabric prepared in Comparative Example 5 was 3.28 mm, and the variance was 0.0282 mm.2 The nonwoven fabric prepared in Example 1 had an average thickness of 3.24 mm and a variance of only 0.0144 mm. 2 .

[0170] Comparative Example 6

[0171] The difference from Example 1 is that in step S3, the frequency of the combing machine doffer motor is 25Hz.

[0172] Because the carding doffer motor frequency was too high, although it ensured a reduction in neps formation, the actual effect was not improved compared to Example 1. The nonwoven fabric prepared in Comparative Example 6 had an average thickness of 3.22 mm and a variance of 0.0151 mm. 2 The nonwoven fabric prepared in Example 1 had an average thickness of 3.24 mm and a variance of 0.0144 mm. 2 .

[0173] Comparative Example 7

[0174] The difference from Example 1 is that, in step S3, the needle density during mechanical puncture reinforcement is 200 needles / cm². 2 The needle insertion depth is 20mm.

[0175] When the needle punching density and needle punching depth are too large, the degree of fiber damage caused during needle punching increases, resulting in a decrease in the bursting strength of the nonwoven fabric prepared in Comparative Example 7, which is only 248.57 N, lower than the bursting strength of 524.89 N of the nonwoven fabric prepared in Example 1.

[0176] Comparative Example 8

[0177] The difference from Example 1 is that, in step S3, the needle density during mechanical puncture reinforcement is 50 needles / cm². 2 The needle insertion depth is 5mm.

[0178] Due to the low needle density and insufficient depth, the needle cannot hook a sufficient amount of surface fibers to the inner layer of the fiber web during mechanical puncture reinforcement, resulting in a decrease in the bonding strength of the fiber web. The tear strength of the nonwoven fabric prepared in Comparative Example 8 is 146N, which is lower than the tear strength of 355N of the nonwoven fabric prepared in Example 1.

Claims

1. A method for preparing dry-laid acrylic staple fiber nonwoven fabric, characterized in that, Includes the following steps: S1 prepares a spinning solution by combining a polymer including polyacrylonitrile with a solvent, and spins nascent fibers using a dry process with nitrogen as the exchange medium. S2 nascent fibers are washed, stretched, crimped, oiled, cut, and dried to obtain dry-process acrylic staple fibers; S3 short fibers are first opened, mixed, and carded into a web, then arranged randomly to form a fluffy fiber web, and finally reinforced by mechanical puncture to produce dry-laid acrylic short fiber nonwoven fabric.

2. The method for preparing dry-laid acrylic staple fiber nonwoven fabric as described in claim 1, characterized in that, In step S1, polyacrylonitrile is produced by using acrylonitrile as a monomer and employing an aqueous suspension method.

3. The method for preparing dry-laid acrylic staple fiber nonwoven fabric as described in claim 1, characterized in that, In step S1, the solvent used is dimethylacetamide, dimethylformamide, or dimethyl sulfoxide.

4. The method for preparing dry-laid acrylic staple fiber nonwoven fabric as described in claim 1, characterized in that, In step S1, the concentration of the spinning solution is 25-30 wt.%.

5. The method for preparing dry-laid acrylic staple fiber nonwoven fabric as described in claim 1, characterized in that, In step S2, the nominal linear density of the short fiber is 1-2.78 dtex, and the nominal cut length is 28 mm or 32 mm.

6. The method for preparing dry-laid acrylic staple fiber nonwoven fabric as described in claim 1, characterized in that, In step S2, the speed of the drive motor of the stretching machine during water washing is 700-850 rpm, and the exit linear velocity of the stretching machine is 325-395 m / min.

7. The method for preparing dry-laid acrylic staple fiber nonwoven fabric as described in claim 1, characterized in that, In step S3, a nail board opening machine is used during the opening process, and the motor frequency of the cylinder opening machine is 35-45Hz; during the mixing process, the motor frequency of the corner curtain is 45-50Hz.

8. The method for preparing dry-laid acrylic staple fiber nonwoven fabric as described in claim 1, characterized in that, In step S3, the frequency of the combing machine doffer motor is 15-20Hz.

9. The method for preparing dry-laid acrylic staple fiber nonwoven fabric as described in claim 1, characterized in that, In step S3, during mechanical puncture reinforcement, the needle density is 100-150 needles / cm². 2 The needle insertion depth is 10-15mm.