Gradient pore structure viscose-based short fiber solid felt preparation process and preparation equipment

Abstract

The invention provides a preparation process and preparation equipment for a viscose-based short fiber solid felt with a gradient pore structure, and relates to the technical field of solid felt preparation, and the preparation process comprises the following steps: carrying out pre-needling reinforcement treatment on a carded fiber web, and carrying out pre-needling reinforcement treatment on the carded fiber web through a pre-needling machine in a needling unit, with the needling frequency of the pre-needling machine being 500-800 times / min. The viscose-based short fiber solid felt with the gradient pore structure is prepared by selecting viscose-based short fibers with different linear densities and lengths, reasonably mixing and proportioning and combining a gradient needling treatment process, the preparation process is simple and easy to implement, the pore gradient distribution of the solid felt can be accurately regulated and controlled, the special requirements of different fields on the pore structure of the material are met, and the application prospect is wide. The problems that the pore structure of the viscose-based short fiber solid felt prepared by the traditional process is usually relatively single and uniform and is difficult to meet the strict requirements of some special application scenes on gradient change of the pore structure of the material are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of preparation of solid felts, and particularly to a preparation process and preparation equipment for a viscose-based short fiber solid felt with a gradient pore structure. Background Art

[0002] Viscose-based short fiber solid felts play a crucial role in many fields such as medical and health, high-end filtration materials, and clothing linings due to their excellent hygroscopicity, outstanding air permeability, and soft and skin-friendly characteristics, and have extremely broad application prospects. However, the pore structure of viscose-based short fiber solid felts prepared by traditional processes is often relatively single and uniform, and it is difficult to meet the strict requirements of some special application scenarios for a gradient change in the pore structure of the material. Taking the filtration field as an example, in actual applications, in the face of particulate matters with different particle sizes, it is difficult for a filtration material with a single pore structure to achieve efficient and precise filtration effects. Another example is in the medical and health field, where there are no gradient differences in the moisture absorption rate and mechanical properties of dressings made of solid felts with a single pore structure, and functional zoning cannot be achieved, resulting in poor applicability. Summary of the Invention

[0003] The purpose of the present invention is to provide a preparation process and preparation equipment for a viscose-based short fiber solid felt with a gradient pore structure to solve the problem that the pore structure of traditional viscose-based short fiber solid felts is uniform and cannot meet the requirements of special occasions as mentioned in the above background art.

[0004] In the first aspect of the present invention, a preparation process and preparation equipment for a viscose-based short fiber solid felt with a gradient pore structure are provided, which specifically include the following steps: I. Select viscose-based short fibers with different linear densities and lengths as raw materials, where the linear density ranges from 1.0 to 3.0 dtex and the length ranges from 20 to 60 mm. Screen the selected raw material fibers to remove impurities and short fibers, and then perform pre-opening treatment to preliminarily disperse the fibers; II. Put viscose-based short fibers with different linear densities and lengths into a mixing tank body in proportion for mixing. The mixing ratio is adjusted according to the required gradient pore structure. To achieve a gradient structure with gradually decreasing pores from the upper layer to the lower layer, fibers with a smaller linear density and shorter length are selected for the upper layer, and fibers with a larger linear density and longer length are selected for the lower layer. During the mixing process, mechanical stirring is used, with a stirring speed of 200 - 300 r / min and a stirring time of 10 - 15 min to make the fibers mix evenly; III. Comb the mixed fibers through a carding unit. The cylinder speed of the carding unit is 300 - 500 r / min, the doffer speed is 50 - 100 r / min, and the carding gauge is 0.1 - 0.3 mm. During the carding process, adjust the feeding amount and output speed of the carding machine according to the requirements of the gradient pore structure to form a fiber web with a certain thickness and fiber distribution gradient. To achieve a sparser upper layer and a denser lower layer of fibers, during the carding process, the feeding amount of the upper layer fibers can be appropriately reduced, and the output speed can be appropriately increased; the feeding amount of the lower layer fibers can be appropriately increased, and the output speed can be appropriately reduced. IV. Perform pre-needling reinforcement treatment on the carded fiber web. Use the pre-needling machine in the needling unit to perform pre-needling reinforcement treatment on the carded fiber web. The needling frequency of the pre-needling machine is 500 - 800 times / min, the needling depth is 10 - 15 mm, and the needling density is 50 - 100 needles / cm². The role of pre-needling is to initially form a certain strength of the fiber web to prevent the fiber web from deforming and breaking during subsequent processing. V. The pre-needled fiber web enters the gradient needling machine in the needling unit for shaping. The gradient needling machine has upper, middle, and lower needling zones. The needling density of the upper needling zone is 100 - 150 needles / cm², and the needling depth is 15 - 20 mm; the needling density of the middle needling zone is 150 - 200 needles / cm², and the needling depth is 10 - 15 mm; the needling density of the lower needling zone is 200 - 250 needles / cm², and the needling depth is 5 - 10 mm. Through gradient needling, the fibers in the fiber web are entangled with each other to form a gradient structure with gradually decreasing pores from the upper layer to the lower layer. VI. Feed the solid felt after gradient needling shaping into the heat setting unit through the conveying unit for heat setting. The heat setting temperature is 100 - 150 °C, and the time is 10 - 20 min. The purpose of heat setting is to stabilize the structure of the solid felt and improve its dimensional stability and mechanical properties. VII. The heat-set solid felt enters the water washing unit through the conveying unit, and the water washing unit cleans the impurities and residual oil agents on the solid felt. VIII. The solid felt after water washing enters the drying unit through the conveying unit. The drying temperature of the drying unit is 80 - 100 °C, and the time is 20 - 30 min. IX. The dried solid felt enters the finishing unit through the conveying unit, and the finishing unit performs surface treatment on the solid felt to improve the surface performance of the solid felt.

[0005] Further, the proportion of the fibers mixed in the mixing tank body in step two is as follows: the upper-layer fibers are fibers with a linear density of 1.0 - 1.5 dtex and a length of 20 - 30 mm, accounting for 30% - 40%; the middle-layer fibers are fibers with a linear density of 1.5 - 2.5 dtex and a length of 30 - 50 mm, accounting for 30% - 40%; the lower-layer fibers are fibers with a linear density of 2.5 - 3.0 dtex and a length of 50 - 60 mm, accounting for 30% - 40%.

[0006] Further, for the gradient needling machine of the needling unit in step five, the needling parameters of each needling area can be adjusted independently. According to the design of the gradient pore structure, from the upper layer to the lower layer, the needling density gradually increases and the needling depth gradually decreases.

[0007] Further, the preparation equipment for a preparation process of a viscose-based short fiber solid felt with a gradient pore structure includes: a mixing tank body, a carding unit, a needling unit, a conveying unit, a heat setting unit, a water washing unit, a drying unit, and a finishing unit. The heat setting unit, the water washing unit, the drying unit, and the finishing unit are sequentially arranged from front to back on the top of the conveying unit; the needling unit is located in front of the conveying unit; the carding unit is located in front of the needling unit; the mixing tank body is located in front of the carding unit.

[0008] Further, a main body frame is fixedly installed inside the water washing unit; supply conduits are fixedly installed on the left and right inside the main body frame; the inlet end of the supply conduit is connected to an external water supply device; a pushing cylinder body is fixedly installed on the front side of the main body frame; a hollow connecting sliding tube is slidably installed inside the supply conduit; a solid connecting sliding tube is fixedly installed on the output end of the pushing cylinder body; two U-shaped spray conduits are fixedly installed on the two connecting sliding tubes together.

[0009] Further, a switching gear is rotatably installed on the spray conduit; a connecting cross bar is eccentrically installed on the switching gear; a switching member is fixedly installed on the connecting cross bar; the switching member is also rotatably installed on the spray conduit; an installation plug is fixedly installed at the end of the switching member; a water washing nozzle is inserted inside the installation plug; two detachable card slots are opened on the circumferential outer wall of the water washing nozzle.

[0010] Further, two rigid card slots are also opened on the circumferential outer wall of the water washing nozzle; the two rigid card slots and the two detachable card slots are arranged in a cross shape inside the water washing nozzle; a detachable card head is slidably installed inside the installation plug.

[0011] Further, the inner end of the detachable chuck is in a hemispherical structure; a spring A is jointly embedded between the outer end of the detachable chuck and the interior of the mounting plug; a rigid chuck is also slidably mounted inside the mounting plug; the outer end of the rigid chuck is in a hemispherical structure.

[0012] Further, the two rigid chucks and the two detachable chucks are arranged in a cross shape inside the mounting plug; an embedded disc is fixedly mounted on the circumferential outer wall of the rigid chuck; the embedded disc is in a disc shape; a spring B is jointly embedded between the outer side of the embedded disc and the interior of the mounting plug; a conversion guide disc is fixedly mounted on the spray conduit.

[0013] Further, an installation ring groove is formed inside the conversion guide disc; a conversion guide ring is fixedly mounted inside the installation ring groove; the inner side surface of the conversion guide ring is in an inclined structure; a guiding sliding groove is formed on the outer wall of the conversion guide disc; the connecting cross bar is slidably mounted in the guiding sliding groove; a driving rack is fixedly mounted on the main body frame; the driving rack is meshed with the switching gear; a unit cover plate is rotatably mounted on the top of the water washing unit.

[0014] The present invention provides a preparation process and preparation equipment for a viscose-based short fiber solid felt with a gradient pore structure, having the following beneficial effects: 1. By selecting viscose-based short fibers with different linear densities and lengths, carrying out reasonable mixing ratios, and then combining with a gradient needling treatment process, the present invention prepares a viscose-based short fiber solid felt with a gradient pore structure. This preparation process is simple and easy to implement, can accurately control the pore gradient distribution of the solid felt, meet the special requirements of different fields for the pore structure of materials, and the prepared solid felt has the advantages of moisture absorption and breathability, and its mechanical properties are also significantly improved, having broad application prospects in the fields of filtration, medical and health, clothing, etc.; 2. When the viscose-based short fiber solid felt with a gradient pore structure prepared by this process is applied in the filtration field, because the solid felt has a gradient pore structure from large to small, it realizes the classification filtration of particles with different particle sizes, improving the filtration effect of the solid felt; 3. When the viscose-based short fiber solid felt with a gradient pore structure prepared by this process is applied in the medical and health field, the moisture absorption rate and mechanical properties of the medical dressings made of this solid felt have gradient differences, and the medical dressings can be functionally partitioned according to actual use requirements, and can better adapt to the growth and metabolism of human tissues; 4. After the top push cylinder body in the present invention is started, it will drive the connected connecting slide pipe and spray conduit to move. During this movement, the switching member will rotate 180 degrees, prompting the water washing nozzles carried on the upper and lower mounting plugs to exchange positions and enabling the corresponding water washing nozzles to communicate with the spray conduit, achieving the rapid replacement of the water washing nozzles; 5. When the water-washing nozzle is switched to the upper position, its hard positioning will be automatically released, which provides great convenience for disassembling and replacing the removed water-washing nozzle. When the water-washing nozzle is switched to the lower position for use, it will be automatically hard-positioned to ensure its sufficient stability during use and prevent situations such as shaking or displacement. This design of the replacement steps for the water-washing nozzle fully considers the actual production requirements, effectively ensuring that the water-washing step of this process will not be delayed due to nozzle replacement and always maintaining an efficient and smooth process operation, greatly improving the overall production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings of the embodiments will be briefly introduced below.

[0016] The accompanying drawings in the following description only relate to some embodiments of the present invention and do not limit the present invention.

[0017] In the accompanying drawings: Figure 1 shows the overall structural schematic diagram of the preparation equipment in the preparation process of the present invention; Figure 2 shows the structural schematic diagram of the water-washing unit of the preparation equipment in the preparation process of the present invention; Figure 3 shows the structural schematic diagram of the driving rack and the switching member of the preparation equipment in the preparation process of the present invention; Figure 4 shows the structural schematic diagram of the spray conduit and the conversion guide plate of the preparation equipment in the preparation process of the present invention; Figure 5 shows the structural schematic diagram of the switching member and the water-washing nozzle of the preparation equipment in the preparation process of the present invention; Figure 6 shows the semi-sectional structural schematic diagram of the switching member of the preparation equipment in the preparation process of the present invention; Figure 7 shows the semi-sectional structural schematic diagram of the switching member and the conversion guide plate of the preparation equipment in the preparation process of the present invention; Figure 8 shows the overall process module schematic diagram of the preparation process of the present invention.

[0018] List of reference numerals: 1. Mixing tank body; 2. Carding unit; 3. Needling unit; 4. Conveying unit; 5. Heat setting unit; 6. Water washing unit; 601. Main body frame; 602. Supply conduit; 603. Pushing cylinder body; 604. Connecting slide pipe; 605. Spraying conduit; 606. Switching gear; 607. Connecting cross bar; 608. Switching part; 609. Installation plug; 6010. Water washing nozzle; 6011. Removable card slot; 6012. Rigid card slot; 6013. Removable card head; 6014. Spring A; 6015. Rigid card head; 6016. Embedding disc; 6017. Spring B; 6018. Conversion guide disc; 6019. Installation ring groove; 6020. Conversion guide ring; 6021. Guide chute; 6022. Driving rack; 6023. Unit cover plate; 7. Drying unit; 8. Finishing unit. Detailed implementation mode

[0019] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the described embodiments of the present invention without creative efforts shall fall within the scope of protection of the present invention.

[0020] Please refer to Figures 1 to 8 : Embodiment 1: The present invention provides a preparation process and preparation equipment for a viscose-based short fiber solid felt with a gradient pore structure, including the following steps: I. Select viscose-based short fibers with different linear densities and lengths as raw materials, where the linear density ranges from 1.0 to 3.0 dtex and the length ranges from 20 to 60 mm. Screen the selected raw material fibers to remove impurities and short fibers, and then perform preliminary loosening treatment to preliminarily disperse the fibers; II. Put viscose-based short fibers with different linear densities and lengths into the mixing tank body 1 in proportion for mixing. The mixing ratio is adjusted according to the required gradient pore structure. To achieve a gradient structure with gradually decreasing pores from the upper layer to the lower layer, fibers with a smaller linear density and shorter length are selected for the upper layer, and fibers with a larger linear density and longer length are selected for the lower layer. During the mixing process, mechanical stirring is used, the stirring speed is 200 - 300 r / min, and the stirring time is 10 - 15 min to make the fibers mix evenly; III. Comb the mixed fibers through the carding unit 2. The cylinder speed of the carding unit 2 is 300 - 500 r / min, the doffer speed is 50 - 100 r / min, and the carding gauge is 0.1 - 0.3 mm. During the carding process, according to the requirements of the gradient pore structure, adjust the feeding amount and output speed of the carding machine to form a fiber web with a certain thickness and fiber distribution gradient. In order to achieve a sparser upper layer of fibers and a denser lower layer of fibers, during the carding process, the feeding amount of the upper layer of fibers can be appropriately reduced, the output speed can be appropriately increased, the feeding amount of the lower layer of fibers can be appropriately increased, and the output speed can be appropriately reduced; IV. Perform pre-needling reinforcement treatment on the carded fiber web. Use the pre-needling machine in the needling unit 3 to perform pre-needling reinforcement treatment on the carded fiber web. The needling frequency of the pre-needling machine is 500 - 800 times / min, the needling depth is 10 - 15 mm, and the needling density is 50 - 100 needles / cm². The role of pre-needling is to initially form a certain strength of the fiber web to prevent the fiber web from deforming and breaking during subsequent processing; V. The pre-needled fiber web enters the gradient needling machine in the needling unit 3 for forming treatment. The gradient needling machine has three needling zones: upper, middle, and lower. The needling density of the upper needling zone is 100 - 150 needles / cm², the needling depth is 15 - 20 mm, the needling density of the middle needling zone is 150 - 200 needles / cm², the needling depth is 10 - 15 mm, and the needling density of the lower needling zone is 200 - 250 needles / cm², the needling depth is 5 - 10 mm. Through gradient needling, the fibers in the fiber web are entangled with each other to form a gradient structure with gradually decreasing pores from the upper layer to the lower layer; VI. Feed the solid felt after gradient needling forming into the heat setting unit 5 through the conveying unit 4 for heat setting treatment. The heat setting temperature is 100 - 150 °C, and the time is 10 - 20 min. The purpose of heat setting is to stabilize the structure of the solid felt and improve its dimensional stability and mechanical properties; VII. The heat-set solid felt enters the water washing unit 6 through the conveying unit 4. The water washing unit 6 cleans the impurities and residual oil agents on the solid felt; VIII. The solid felt after water washing enters the drying unit 7 through the conveying unit 4. The drying temperature of the drying unit 7 is 80 - 100 °C, and the time is 20 - 30 min; IX. The dried solid felt enters the finishing unit 8 through the conveying unit 4. The finishing unit 8 performs surface treatment on the solid felt to improve the surface performance of the solid felt; In Step 2, the proportion of fibers mixed in the mixing tank 1 is as follows: for the upper-layer fibers, fibers with a linear density of 1.0 - 1.5 dtex and a length of 20 - 30 mm are used, with a proportion of 30% - 40%; for the middle-layer fibers, fibers with a linear density of 1.5 - 2.5 dtex and a length of 30 - 50 mm are used, with a proportion of 30% - 40%; for the lower-layer fibers, fibers with a linear density of 2.5 - 3.0 dtex and a length of 50 - 60 mm are used, with a proportion of 30% - 40%. In Step 5, the needling parameters of each needling zone of the gradient needling machine of the needling unit 3 can be adjusted independently. According to the design of the gradient pore structure, from the upper layer to the lower layer, the needling density gradually increases and the needling depth gradually decreases. On the top of the conveyor unit 4, there are successively arranged a heat setting unit 5, a water washing unit 6, a drying unit 7 and a finishing unit 8 from front to back; the needling unit 3 is located in front of the conveyor unit 4; the carding unit 2 is located in front of the needling unit 3; the mixing tank body 1 is located in front of the carding unit 2; a main body frame 601 is fixedly installed inside the water washing unit 6; supply conduits 602 are fixedly installed on the left and right inside the main body frame 601; the inlet end of the supply conduit 602 is connected to an external water supply device; a pushing cylinder body 603 is fixedly installed on the front side of the main body frame 601; a hollow connecting slide tube 604 is slidably installed inside the supply conduit 602; a solid connecting slide tube 604 is fixedly installed on the output end of the pushing cylinder body 603; two U-shaped spray conduits 605 are fixedly installed on the two connecting slide tubes 604 together; a switching gear 606 is rotatably installed on the spray conduit 605; a connecting cross bar 607 is eccentrically installed on the switching gear 606; a switching member 608 is fixedly installed on the connecting cross bar 607; the switching member 608 is also rotatably installed on the spray conduit 605; an installation plug 609 is fixedly installed at the end of the switching member 608; a water washing nozzle 6010 is inserted inside the installation plug 609; two detachable card slots 6011 are formed on the circumferential outer wall of the water washing nozzle 6010; two rigid card slots 6012 are also formed on the circumferential outer wall of the water washing nozzle 6010; the two rigid card slots 6012 and the two detachable card slots 6011 are arranged in a cross shape inside the water washing nozzle 6010; a detachable card head 6013 is slidably installed inside the installation plug 609; the inner end of the detachable card head 6013 is in a hemispherical structure; a spring A6014 is jointly embedded between the outer end of the detachable card head 6013 and the inside of the installation plug 609; a rigid card head 6015 is also slidably installed inside the installation plug 609; the outer end of the rigid card head 6015 is in a hemispherical structure; the two rigid card heads 6015 and the two detachable card heads 6013 are arranged in a cross shape inside the installation plug 609; an embedding disc 6016 is fixedly installed on the circumferential outer wall of the rigid card head 6015; the embedding disc 6016 is in a disc shape; a spring B6017 is jointly embedded between the outside of the embedding disc 6016 and the inside of the installation plug 609; a conversion guide disc 6018 is fixedly installed on the spray conduit 605; an installation ring groove 6019 is formed on the inner side of the conversion guide disc 6018; a conversion guide ring 6020 is fixedly installed inside the installation ring groove 6019; the inner side surface of the conversion guide ring 6020 is in an inclined structure; a guiding chute 6021 is formed on the outer wall of the conversion guide disc 6018; the connecting cross bar 607 is slidably installed in the guiding chute 6021; a driving rack 6022 is fixedly installed on the main body frame 601; the driving rack 6022 is meshed and connected with the switching gear 606; a unit cover plate 6023 is rotatably installed on the top of the water washing unit 6.

[0021] Example 2. On the basis of Example 1, viscose staple fibers with a linear density of 1.2 dtex and a length of 25 mm are selected as the upper-layer raw material, viscose staple fibers with a linear density of 2.0 dtex and a length of 40 mm are selected as the middle-layer raw material, and viscose staple fibers with a linear density of 2.8 dtex and a length of 55 mm are selected as the lower-layer raw material. The three kinds of fibers are respectively screened to remove impurities and short lint, and then pre-opened to preliminarily disperse the fibers. The upper-layer fibers, middle-layer fibers, and lower-layer fibers are put into the mixing tank 1 in a ratio of 35%, 35%, and 30% for mixing. The mechanical stirring method is adopted, the stirring speed is 250 r / min, and the stirring time is 12 min to make the fibers evenly mixed. The mixed fibers are carded by the carding unit 2. The cylinder speed of the carding unit 2 is 400 r / min, the doffer speed is 70 r / min, and the carding gauge is 0.2 mm. Adjust the feeding amount and output speed of the carding unit 2 so that the feeding amount of the upper-layer fibers is 50 g / min and the output speed is 10 m / min, the feeding amount of the middle-layer fibers is 60 g / min and the output speed is 8 m / min, and the feeding amount of the lower-layer fibers is 70 g / min and the output speed is 6 m / min to form a fiber web with a certain thickness and fiber distribution gradient. The carded fiber web is introduced into the pre-needling machine in the needling unit 3 for pre-needling reinforcement treatment. The needling frequency is 600 times / min, the needling depth is 12 mm, and the needling density is 80 needles / cm². The pre-needled fiber web enters the gradient needling machine in the needling unit 3 for shaping treatment. The needling density in the upper-layer needling area is 120 needles / cm² and the needling depth is 18 mm; the needling density in the middle-layer needling area is 180 needles / cm² and the needling depth is 12 mm; the needling density in the lower-layer needling area is 220 needles / cm² and the needling depth is 8 mm. The solid felt after gradient needling shaping is introduced into the heat setting unit 5 by the conveying unit 4 for heat setting treatment. The heat setting temperature is 120 °C and the time is 15 min. The heat-set solid felt is washed, dried, and surface-finished. The washing temperature is 40 °C, the drying temperature is 90 °C, and the time is 25 min. The surface finishing is carried out by using a softener treatment.

[0022] Example 3: On the basis of Example 1, viscose-based staple fibers with a linear density of 1.0 dtex and a length of 20 mm are selected as the upper-layer raw material, viscose-based staple fibers with a linear density of 2.5 dtex and a length of 50 mm are selected as the middle-layer raw material, and viscose-based staple fibers with a linear density of 3.0 dtex and a length of 60 mm are selected as the lower-layer raw material. The three types of fibers are respectively screened to remove impurities and short lint, and then pre-opened to preliminarily disperse the fibers. The upper-layer fibers, middle-layer fibers, and lower-layer fibers are put into the mixing tank 1 in a ratio of 40%, 30%, and 30% for mixing. The mechanical stirring method is adopted, the stirring speed is 300 r / min, and the stirring time is 10 min to make the fibers evenly mixed. The mixed fibers are combed by the carding unit 2. The cylinder speed of the carding unit 2 is 500 r / min, the doffer speed is 100 r / min, and the carding gauge is 0.1 mm. Adjust the feeding amount and output speed of the carding unit 2 so that the feeding amount of the upper-layer fibers is 40 g / min and the output speed is 12 m / min, the feeding amount of the middle-layer fibers is 60 g / min and the output speed is 8 m / min, and the feeding amount of the lower-layer fibers is 80 g / min and the output speed is 5 m / min to form a fibrous web with a certain thickness and fiber distribution gradient. The combed fibrous web is introduced into the pre-needling machine in the needling unit 3 for pre-needling reinforcement treatment. The needling frequency is 800 times / min, the needling depth is 10 mm, and the needling density is 100 needles / cm². The pre-needled fibrous web enters the gradient needling machine in the needling unit 3 for forming treatment. The needling density in the upper-layer needling area is 150 needles / cm², the needling depth is 20 mm, the needling density in the middle-layer needling area is 200 needles / cm², the needling depth is 10 mm, and the needling density in the lower-layer needling area is 250 needles / cm², and the needling depth is 5 mm. The solid felt after gradient needling forming is introduced into the heat setting unit 5 by the conveying unit 4 for heat setting treatment. The heat setting temperature is 150 °C and the time is 10 min. The heat-set solid felt is washed, dried, and surface-finished. The washing temperature is 50 °C, the drying temperature is 100 °C, and the time is 20 min. The surface finishing is treated with an antistatic agent.

[0023] Nozzle replacement method: Start the push cylinder 603 to move it backward with the connecting slide pipe 604 and the spray conduit 605. During the movement, the switching gear 606 will cooperate with the driving rack 6022 during the backward movement to drive the connecting crossbar 607 and the switching member 608 to rotate, causing the switching member 608 to drive the mounting plug 609 to rotate 180 degrees, so as to swap the positions of the upper and lower water washing nozzles 6010. During the swapping process, the upper rigid chuck 6015 slides downward along the conversion guide ring 6020, causing the upper rigid chuck 6015 to gradually move inward and insert into the inside of the rigid card slot 6012 by using the inclined structure of the conversion guide ring 6020, so that the water washing nozzle 6010 ready to be put into use is rigidly fixed to ensure the stability after the water washing nozzle 6010 is put into use. And the lower rigid chuck 6015 slides upward along the conversion guide ring 6020, causing the rigid chuck 6015 to gradually stop being pushed by the conversion guide ring 6020, and the rigid chuck 6015 moves outward under the action of the spring B6017, so that the inner end of the rigid chuck 6015 disengages from the rigid card slot 6012, canceling the positioning of the upper water washing nozzle 6010. At this time, the upper water washing nozzle 6010 is only connected to the mounting plug 609 through the detachable chuck 6013, and the operator only needs to pull it out slightly with a little force to disassemble the water washing nozzle 6010.

[0024] In this article, the following points need to be noted: 1. The attached drawings of the embodiments of the present invention only relate to the structures involved in the embodiments of the present invention, and other structures can refer to the general design.

[0025] 2. Without conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other to obtain new embodiments.

[0026] The above is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention can easily think of changes or substitutions, which should all be covered by the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. A preparation process for a viscose-based short fiber solid felt with a gradient pore structure, characterized in that, It includes the following steps:

1. Select viscose-based staple fibers with different linear densities and lengths as raw materials, and screen the selected raw material fibers; 2. Put viscose-based staple fibers with different linear densities and lengths into the mixing tank body (1) according to a ratio for mixing. The mixing ratio is adjusted according to the required gradient pore structure, and mechanical stirring is adopted during the mixing process; 3. Card the mixed fibers through a carding unit (2), and adjust the feeding amount and output speed of the carding machine according to the requirements of the gradient pore structure; 4. Carry out pre-needling reinforcement treatment on the carded web. Use the pre-needling machine in the needling unit (3) to carry out pre-needling reinforcement treatment on the carded web; 5. The pre-needled web enters the gradient needling machine in the needling unit (3) for forming treatment. The gradient needling machine has upper, middle and lower needling zones; 6. Guide the solid felt after gradient needling forming into the heat setting unit (5) through the conveying unit (4) for heat setting treatment; 7. The heat-set solid felt enters the water washing unit (6) through the conveying unit (4); 8. The solid felt after water washing enters the drying unit (7) through the conveying unit (4); 9. The dried solid felt enters the finishing unit (8) through the conveying unit (4), and the finishing unit (8) performs surface treatment on the solid felt.

2. The preparation process of the viscose-based short fiber solid felt with a gradient pore structure according to claim 1, characterized in that, In step 2, the ratio of the fibers mixed in the mixing tank body (1) is as follows: the upper-layer fibers use fibers with a linear density of 1.0 - 1.5 dtex and a length of 20 - 30 mm, accounting for 30% - 40%; the middle-layer fibers use fibers with a linear density of 1.5 - 2.5 dtex and a length of 30 - 50 mm, accounting for 30% - 40%; the lower-layer fibers use fibers with a linear density of 2.5 - 3.0 dtex and a length of 50 - 60 mm, accounting for 30% - 40%.

3. The preparation process of the viscose-based short fiber solid felt with a gradient pore structure according to claim 1, characterized in that In step 5, the needling parameters of each needling zone of the gradient needling machine in the needling unit (3) can be adjusted independently. According to the design of the gradient pore structure, from the upper layer to the lower layer, the needling density gradually increases and the needling depth gradually decreases.

4. A preparation device for implementing the preparation process of a viscose-based short fiber solid felt with a gradient pore structure according to any one of claims 1-3, characterized in that, It includes: A mixing tank body (1), a carding unit (2), a needling unit (3), a conveying unit (4), a heat setting unit (5), a water washing unit (6), a drying unit (7) and a finishing unit (8). The heat setting unit (5), the water washing unit (6), the drying unit (7) and the finishing unit (8) are sequentially arranged from front to back on the top of the conveying unit (4); the needling unit (3) is located in front of the conveying unit (4); the carding unit (2) is located in front of the needling unit (3); the mixing tank body (1) is located in front of the carding unit (2).

5. The preparation equipment for the viscose-based short fiber solid felt with a gradient pore structure according to claim 4, characterized in that, Inside the water washing unit (6), a main body frame (601) is fixedly installed; on the left and right inside the main body frame (601), a supply conduit (602) is fixedly installed; the inlet end of the supply conduit (602) is connected to an external water supply device; on the front side of the main body frame (601), a pushing cylinder block (603) is fixedly installed; inside the supply conduit (602), a hollow connecting sliding tube (604) is slidably installed; on the output end of the pushing cylinder block (603), a solid connecting sliding tube (604) is fixedly installed; on the two connecting sliding tubes (604), two U-shaped spray conduits (605) are fixedly installed together.

6. The preparation equipment for the viscose-based staple fiber solid felt with a gradient pore structure according to claim 5, characterized in that, On the spray conduit (605), a switching gear (606) is rotatably installed; on the switching gear (606), a connecting cross bar (607) is eccentrically installed; on the connecting cross bar (607), a switching member (608) is fixedly installed; the switching member (608) is also rotatably installed on the spray conduit (605); at the end of the switching member (608), an installation plug (609) is fixedly installed; inside the installation plug (609), a water washing nozzle (6010) is inserted; on the circumferential outer wall of the water washing nozzle (6010), two detachable card slots (6011) are opened.

7. The preparation equipment for the preparation process of the viscose-based short fiber solid felt with a gradient pore structure according to claim 6, characterized in that, On the circumferential outer wall of the water washing nozzle (6010), two rigid card slots (6012) are also opened; the two rigid card slots (6012) and the two detachable card slots (6011) are arranged in a cross shape inside the water washing nozzle (6010); inside the installation plug (609), a detachable card head (6013) is slidably installed.

8. The preparation equipment for the preparation process of the viscose-based short fiber solid felt with a gradient pore structure according to claim 7, characterized in that, The inner end of the detachable card head (6013) is in a hemispherical structure; between the outer end of the detachable card head (6013) and the inside of the installation plug (609), a spring A (6014) is jointly embedded; inside the installation plug (609), a rigid card head (6015) is also slidably installed; the outer end of the rigid card head (6015) is in a hemispherical structure.

9. The preparation equipment for the viscose-based short fiber solid felt with a gradient pore structure according to claim 8, characterized in that, The two rigid card heads (6015) and the two detachable card heads (6013) are arranged in a cross shape inside the installation plug (609); on the circumferential outer wall of the rigid card head (6015), an embedding disc (6016) is fixedly installed; the embedding disc (6016) is in a disc shape; between the outside of the embedding disc (6016) and the inside of the installation plug (609), a spring B (6017) is jointly embedded; on the spray conduit (605), a conversion guide disc (6018) is fixedly installed.

10. The preparation equipment for the preparation process of the viscose-based short fiber solid felt with a gradient pore structure according to claim 9, characterized in that, An installation ring groove (6019) is formed on the inner side of the conversion guide disc (6018); a conversion guide ring (6020) is fixedly installed inside the installation ring groove (6019); the inner side surface of the conversion guide ring (6020) is of an inclined structure; a guide sliding groove (6021) is formed on the outer wall of the conversion guide disc (6018); the connecting cross bar (607) is slidably installed in the guide sliding groove (6021); a driving rack (6022) is fixedly installed on the main body frame (601); the driving rack (6022) is meshed with a switching gear (606); a unit cover plate (6023) is rotatably installed on the top of the water washing unit (6).

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