A method of manufacturing an absorbent core having a layered, lofty fibrous structure

Abstract

The present application relates to the technical field of absorbent products, and discloses a manufacturing method of an absorbent core with a layered fluffy fiber structure, which comprises the following steps: firstly, a composite surface layer is formed on a forming net belt through a composite forming device; then, a first fluffy layer and a second fluffy layer are formed on the surface of the composite surface layer in sequence through multiple forming devices; then, liquid-absorbing liquid is added into the first fluffy layer and the second fluffy layer, and the content of the liquid-absorbing liquid decreases from top to bottom; and finally, a fluffy bottom layer without the liquid-absorbing liquid is added, and then the whole is heated and shaped. The present application adopts a reverse processing mode from the surface layer to the bottom layer, and the blocking strip is close to the surface of the composite surface layer instead of the fluffy layer, so that the problem of core layering caused by the blocking strip pressing material is avoided, the production reliability is improved, the blocking strip covers part of the core flow guide groove, and temporary liquid storage space is provided, the groove depth increases after the core absorbs water and expands, liquid infiltration is absorbed from bottom to top each time, the lower layer is saturated first, the upper layer retains a certain amount of liquid-absorbing liquid, liquid backflow is reduced, and the surface layer is kept dry.

Description

Technical Field

[0001] This invention relates to the field of absorbent products technology, and specifically to a method for manufacturing an absorbent core with a layered, fluffy fiber structure. Background Technology

[0002] Traditional composite absorbent cores typically consist of a top layer, a composite absorbent intermediate layer, and a bottom layer. The composite absorbent intermediate layer often uses a mixture of hydrophilic fibers and high-molecular-weight absorbent resin particles. This intermediate layer can be configured with multiple layers, each with a different liquid absorption content to enhance absorption. The entire structure is bonded together using hot-melt adhesive to form a composite, hybrid absorbent core. The hydrophilic fibers are often selected from plant fibers such as wood pulp and bamboo pulp. The high-molecular-weight absorbent resin particles are evenly mixed between the fibers, and the adhesive properties of the hot-melt adhesive secure the layers, ensuring the overall structural stability of the core and meeting basic liquid absorption requirements.

[0003] The above-mentioned composite absorbent core forming method is as follows: each layer is formed separately first, and then each layer is composited at once, or a forward composite method is used, consisting of a bottom layer, a composite absorbent intermediate layer, and a top layer. When forming separately, the bottom layer, the composite intermediate layer, and the top layer need to be laid out with fibers and formed separately, and then the three are bonded and fixed together using a composite equipment; the forward composite method is to lay the bottom layer, the absorbent intermediate layer, and the top layer on the forming mesh belt in a bottom-to-top order, gradually completing the superposition and composite of each layer. During the process, the forming parameters need to be adjusted multiple times to ensure the adhesion of each layer.

[0004] However, this molding method is cumbersome, requiring each layer to be molded individually, making it suitable only for cores with simple structures. For the production of multi-layered composite cores, each layer is stacked online and then laminated at the end, effectively reducing processing costs. In traditional methods, each layer is molded separately, requiring independent molding equipment, involving numerous steps and significant time consumption. Furthermore, the individual molding and lamination of each layer can easily lead to layer separation. For cores with multi-layered, fluffy structures and special flow-guiding structures, traditional molding methods struggle to achieve accurate layer stacking. Online stacking molding, on the other hand, reduces molding steps, lowers equipment investment and labor costs, and simultaneously improves the bonding effect between the core layers. Summary of the Invention

[0005] To address the technical deficiencies in the prior art, this invention proposes a method for manufacturing an absorbent core with a layered, fluffy fiber structure, which solves the aforementioned technical problems and meets practical needs. The specific technical solution is as follows: A method for manufacturing an absorbent core with a layered, fluffy fiber structure includes the following steps: S1. Low-melting-point fibers and plant fibers are opened and mixed to obtain blended fibers; S2. A portion of the mixed fibers is processed to obtain a composite surface layer, the composite surface layer comprising a surface layer substrate and an absorbent layer; S3. After mixing a portion of the mixed fibers with the absorbent liquid in the first molding equipment, negative pressure airflow molding is performed so that the mixed material formed by the mixed fibers and the absorbent liquid is split and deposited on the composite surface layer by the baffles set at the discharge port of the mixing chamber of the first molding equipment, forming mutually spaced first fluffy layer blocks, and obtaining the first composite. S4. After mixing a portion of the mixed fibers with the absorbent liquid in the second molding equipment, negative pressure airflow molding is performed so that the mixed material formed by the mixed fibers and the absorbent liquid is split and deposited on the first fluffy layer block of the first composite by the baffle set at the discharge port of the mixing chamber of the second molding equipment, forming a second fluffy layer block that overlaps with the first fluffy layer block and is spaced apart from each other, thus obtaining the second composite. S5. A portion of the mixed fibers is molded under negative pressure airflow to obtain a fluffy bottom layer; S6. After combining the fluffy bottom layer with the second composite, the core is heated, cooled and shaped, and then cut to obtain the absorbent core.

[0006] As a further technical solution of the present invention, the liquid content in the first fluffy layer block is greater than or equal to the liquid content in the second fluffy layer block.

[0007] As a further technical solution of the present invention, in step S2, the composite molding equipment includes a fourth molding device and a liquid suction spraying device arranged sequentially along the material feeding direction, and the composite surface layer is formed in the following manner: After the mixed fibers are transported to the mixing chamber of the fourth forming equipment for mixing, they enter the negative pressure chamber of the fourth forming equipment. Under the action of negative pressure, the mixed fibers are air-formed on the surface of the forming mesh belt in the negative pressure chamber of the fourth forming equipment to form the surface substrate. The liquid-absorbing spraying device applies liquid-absorbing particles at intervals to the surface substrate to form a liquid-absorbing layer that is spaced apart from each other on the surface of the surface substrate, thereby obtaining a composite surface layer.

[0008] As a further technical solution of the present invention, in step S2, the composite molding equipment further includes a spraying device disposed between the fourth molding device and the liquid spraying device, and the composite surface layer is formed in the following manner: After the mixed fibers are transported to the mixing chamber of the fourth forming equipment for mixing, they enter the negative pressure chamber of the fourth forming equipment. Under the action of negative pressure, the mixed fibers are air-formed on the surface of the forming mesh belt in the negative pressure chamber of the fourth forming equipment to form the surface substrate. The adhesive is sprayed at intervals onto the upper surface of the surface substrate by the adhesive spraying device; The liquid-absorbing spraying device applies liquid-absorbing particles to the area where the adhesive is sprayed, so as to form a liquid-absorbing layer that is spaced apart from each other on the surface of the surface layer substrate, thereby obtaining a composite surface layer.

[0009] As a further technical solution of the present invention, the mixing chamber of the fourth molding equipment is provided with an upper set of dispersing rollers and a lower set of dispersing rollers distributed vertically. The mixed material entering the mixing chamber of the fourth molding equipment is dispersed and mixed twice by the upper set of dispersing rollers and the lower set of dispersing rollers.

[0010] As a further technical solution of the present invention, steps S3, S4 and S5 respectively use a first molding device, a second molding device and a third molding device to perform negative pressure airflow molding processing; the mixing chambers of the first molding device, the second molding device and the third molding device are all provided with an upper set of dispersing rollers and a lower set of dispersing rollers distributed vertically, and the mixed materials entering the mixing chambers of the first molding device, the second molding device and the third molding device are all dispersed and mixed twice by the upper set of dispersing rollers and the lower set of dispersing rollers; Specifically, step S5 includes: conveying a portion of the mixed fibers to the mixing chamber of the third forming equipment for mixing, and then entering the negative pressure chamber of the third forming equipment, where the mixed fibers are air-formed on the surface of the forming mesh belt to form a fluffy bottom layer.

[0011] As a further technical solution of the present invention, step S3 specifically includes: feeding a portion of the mixed fibers into the mixing chamber of the first forming device, adding absorbent liquid and mixing evenly; the forming mesh belt carrying the composite surface layer into the negative pressure chamber below the mixing chamber, the discharge port of the mixing chamber facing the negative pressure chamber is provided with the baffle to cover the non-forming area, the baffle is close to the composite surface layer below, and airflow forming is performed under the action of negative pressure, the mixed materials formed by the mixed fibers and absorbent liquid are divided into two streams and deposited in the area of ​​the composite surface layer that is not covered, forming the first fluffy layer blocks that are spaced apart from each other.

[0012] As a further technical solution of the present invention, step S4 specifically includes: feeding a portion of the mixed fibers into the mixing chamber of the second molding device, adding absorbent liquid and mixing evenly; the molding mesh belt carrying the first composite into the negative pressure chamber below the mixing chamber, the discharge port of the mixing chamber facing the negative pressure chamber is provided with the baffle to cover the corresponding non-molding area, the baffle is close to the lower composite surface layer, and airflow molding is performed under the action of negative pressure, the composite material formed by the mixed fibers and absorbent liquid is divided into two strands and deposited in the uncovered area of ​​the first fluffy layer block, forming a second fluffy layer block that overlaps with the first fluffy layer block and is spaced apart from each other, and the area where no fibers are deposited constitutes a guide channel.

[0013] As a further technical solution of the present invention, in step S6, the temperature inside the heating box is 110-140℃, and the relative moisture content of the composite formed by the fluffy bottom layer and the second composite is 6-10%.

[0014] As a further technical solution of the present invention, the low melting point fiber is selected from at least one of ES fiber and PE / PET core-sheath fiber, the melting point of the low melting point fiber sheath is 110-140℃, and the plant fiber is selected from at least one of wood pulp fiber, cotton fiber, bamboo pulp fiber, and hemp fiber. The absorbent liquid is selected from any one or more of SAP particles, cross-linked polyacrylamide water-absorbing resin particles, cross-linked polyvinyl alcohol water-absorbing particles, polyglutamic acid cross-linked particles, and superabsorbent fibers.

[0015] The beneficial effects of this invention are as follows: By employing a reverse layering sequence from the top layer to the bottom layer, and utilizing baffles close to the surface of the composite top layer, the problems of material breakage and interlayer misalignment caused by the unevenness of the loose bottom layer in conventional processes are avoided. This allows the first and second loose layers to form smoothly above the composite top layer, and after the baffles are removed, a through-flow channel is formed. After formation, the liquid preferentially collects at the bottom of the channel, and is then absorbed layer by layer from bottom to top by the high-content absorbent liquid in the lower part. The upper absorbent liquid maintains a lower saturation, and even after multiple drainages, there is still absorbent liquid remaining in the area close to the top layer, which can reduce liquid backflow. The channel further provides temporary liquid storage space as the core expands deeper. The overall method ensures stable production of the core structure and improves the dryness of the surface layer after absorption. Attached Figure Description

[0016] Figure 1 This is one of the process flow diagrams of the present invention.

[0017] Figure 2 This is the second process flow diagram of the present invention.

[0018] Figure 3 This is one of the schematic diagrams of a core structure produced by the core manufacturing method of the present invention.

[0019] Figure 4 This is a second schematic diagram of the core structure produced by the core manufacturing method of the present invention.

[0020] Figure 5 This is a simplified structural diagram illustrating the position of the baffle bar in this invention.

[0021] Reference numerals: 1-Composite surface layer; 2-Adhesive; 3-Absorbent layer; 4-First fluffy layer; 5-Second fluffy layer; 6-Fluffy bottom layer; 7-Guide channel; 8-First molding equipment; 9-Second molding equipment; 10-Third molding equipment; 11-Mixing chamber; 12-Negative pressure chamber; 13-Molding mesh belt; 14-Liquid suction spraying device; 15-Glue spraying device; 16-Heating box; 17-Cooling device; 18-Baffle; 19-Composite molding equipment; 20-Fourth molding equipment. Detailed Implementation

[0022] The embodiments of the present invention will be described below with reference to relevant examples. The embodiments of the present invention are not limited to the following examples, and the present invention relates to relevant necessary components in this technical field, which should be regarded as well-known technology in this technical field and can be known and mastered by those skilled in this technical field.

[0023] like Figures 1 to 5 As shown, a method for manufacturing an absorbent core with a layered, fluffy fiber structure includes the following steps: S1. Low-melting-point fibers and plant fibers are opened and mixed to obtain blended fibers; S2. A portion of the mixed fibers is processed to obtain a composite surface layer, the composite surface layer comprising a surface layer substrate and an absorbent layer; S3. After mixing a portion of the mixed fibers with the absorbent liquid in the first molding equipment, negative pressure airflow molding is performed so that the mixed material formed by the mixed fibers and the absorbent liquid is split and deposited on the composite surface layer by the baffles set at the discharge port of the mixing chamber of the first molding equipment, forming mutually spaced first fluffy layer blocks, and obtaining the first composite. S4. After mixing a portion of the mixed fibers with the absorbent liquid in the second molding equipment, negative pressure airflow molding is performed so that the mixed material formed by the mixed fibers and the absorbent liquid is split and deposited on the first fluffy layer block of the first composite by the baffle set at the discharge port of the mixing chamber of the second molding equipment, forming a second fluffy layer block that overlaps with the first fluffy layer block and is spaced apart from each other, thus obtaining the second composite. S5. A portion of the mixed fibers is molded under negative pressure airflow to obtain a fluffy bottom layer; S6. After combining the fluffy bottom layer with the second composite, the core is heated, cooled and shaped, and then cut to obtain the absorbent core.

[0024] This invention employs a reverse processing path from the surface layer to the bottom layer. During production, a structurally stable composite surface layer 1 is first formed using a composite molding equipment 19. Then, baffles 18 are respectively installed at the material discharge ports of the first molding equipment 8 and the second molding equipment 9, bringing the baffles 18 close to the composite surface layer 1. Under negative pressure airflow, a first fluffy layer 4 and a second fluffy layer 5 are sequentially deposited. Finally, a fluffy bottom layer 6 is laminated, and the product is heated by a heating box 16 and shaped by a cooling device 17 to obtain the finished product. In this process, the substrate approached by the baffles 18 is the relatively stable and thin composite surface layer 1, preventing material compression or carrying problems due to the baffles 18's proximity. This ensures that the first fluffy layer 4 and the second fluffy layer 5 can be stably stacked in the preset positions, effectively improving the reliability of core production. Simultaneously, areas not deposited with mixed fibers naturally form an integrated vertical guide channel 7, ensuring the integrity of the core structure.

[0025] In contrast, if a conventional forward processing method from the bottom layer to the top layer is used, the fluffy bottom layer 6 must first be formed by airflow, and then the second fluffy layer 5 and the first fluffy layer 4 must be formed on it in sequence, with the guide channel 7 constructed by the baffle 18. At this time, the base of the baffle 18 is the newly formed fluffy bottom layer 6. During the material feeding process, the baffle 18 will press into the thicker part of the fluffy bottom layer 6 and drag its surface fibers with the continuous movement of the forming mesh belt 13, thereby causing local breakage of the fluffy bottom layer 6, which in turn causes misalignment and delamination between the fluffy bottom layer 6 and the second fluffy layer 5, making it impossible to guarantee the stable forming of the core structure.

[0026] As one of the preferred embodiments of the present invention, the liquid content in the first fluffy layer block is greater than or equal to the liquid content in the second fluffy layer block.

[0027] Specifically, in actual processing, the total amount of liquid added to the first molding device 8 is greater than or equal to the total amount of liquid added to the second molding device 9, while no liquid is added to the mixing chamber 11 of the third molding device 10. This creates a gradient distribution of liquid within the core, meaning the first fluffy layer 4, closest to the composite surface layer 1, has the highest liquid content, followed by the second fluffy layer 5, and the outermost fluffy bottom layer 6 contains no liquid. This gradient distribution is achieved simultaneously with the layered airflow molding process. During the molding of each fluffy layer, the amount of liquid added is directly controlled within the mixing chamber 11 of the corresponding molding device, ensuring uniform distribution and stable, controllable content of liquid within each layer.

[0028] like Figure 1 and Figure 2 As shown, in the core prepared by this method, after urine passes through the composite surface layer 1, it first enters the guide channel 7 and gathers towards the bottom of the core, sequentially wetting the second fluff layer 5 and the first fluff layer 4 from bottom to top. The second fluff layer 5 has a lower liquid absorption content, which can complete the initial liquid absorption and dispersion, and quickly spread the liquid across the entire width of the core. The first fluff layer 4 has a higher liquid absorption content, which can receive the subsequently permeated liquid, achieving stratified liquid locking. After multiple urinations, the first fluff layer 4 close to the composite surface layer 1 can still retain liquid absorption capacity, preventing liquid from seeping back to the surface of the composite surface layer 1 and maintaining the dry state of the surface layer. The fluffy bottom layer 6, which does not contain liquid absorption, can reduce the risk of liquid leakage.

[0029] As one of the preferred embodiments of the present invention, such as Figure 1 and Figure 3 As shown, in step S2, the composite molding equipment includes a fourth molding device and a liquid spraying device arranged sequentially along the material feeding direction. The composite surface layer is formed in the following manner: After the mixed fibers are transported to the mixing chamber of the fourth forming equipment for mixing, they enter the negative pressure chamber of the fourth forming equipment. Under the action of negative pressure, the mixed fibers are air-formed on the surface of the forming mesh belt in the negative pressure chamber of the fourth forming equipment to form the surface substrate. The liquid-absorbing spraying device applies liquid-absorbing particles at intervals to the surface substrate to form a liquid-absorbing layer that is spaced apart from each other on the surface of the surface substrate, thereby obtaining a composite surface layer.

[0030] Specifically, the above describes the first method for forming the composite surface layer 1, a glue-free solution where the surface substrate and absorbent layer 3 are bonded without adhesive. The surface substrate is formed from mixed fibers by airflow molding using a fourth forming device 20. A liquid-absorbing particle spraying device 14 applies liquid-absorbing particles quantitatively to the surface of the surface substrate at preset intervals. The areas of the liquid-absorbing particles are staggered from the positions of the baffles 18 in subsequent processes. The liquid-absorbing particles are partially embedded in the gaps between the surface fibers of the surface substrate, achieving initial positioning through the cohesive force between the fibers, forming a liquid-absorbing layer with intervals. When the core is subsequently heated in the heating chamber 16, the low-melting-point fiber sheath in the mixed fibers melts, bonding and fixing the surface liquid-absorbing particles to the surface substrate fibers. This ensures the adhesion stability of the liquid-absorbing particles without the need for additional adhesive. This solution has a shorter process flow, reduces the problem of core hardening caused by adhesives, and is suitable for core processing with high flexibility requirements.

[0031] As one of the preferred embodiments of the present invention, such as Figure 2 and Figure 4 As shown, in step S2, the composite molding equipment includes a fourth molding device, a glue spraying device, and a liquid suction spraying device arranged sequentially along the material feeding direction. The composite surface layer is formed in the following manner: After the mixed fibers are transported to the mixing chamber of the fourth forming equipment for mixing, they enter the negative pressure chamber of the fourth forming equipment. The mixed fibers are air-formed on the surface of the forming mesh belt in the negative pressure chamber of the fourth forming equipment to form the surface substrate. The adhesive is sprayed at intervals onto the upper surface of the surface substrate by the adhesive spraying device; The liquid-absorbing spraying device applies liquid-absorbing material to the area where the adhesive is sprayed, thereby forming liquid-absorbing areas spaced apart from each other on the surface of the surface layer substrate, resulting in a composite surface layer.

[0032] Specifically, the above describes the second method for forming the composite surface layer 1, which involves bonding the surface layer substrate and the absorbent layer together with an adhesive. The composite surface layer 1 is processed by the fourth forming device 20, the adhesive spraying device 15, and the liquid-absorbing particle spraying device 14 in the composite forming equipment 19. After receiving the mixed fibers, the fourth forming device 20 uniformly deposits the fibers onto the surface of the forming mesh belt 13 under the action of the negative pressure chamber 12, forming the surface layer substrate. The forming mesh belt 13 drives the surface layer substrate along the material feeding direction. The adhesive spraying device 15 sprays adhesive 2 onto the surface of the surface layer substrate at preset intervals, and the spraying area is staggered from the covering position of the baffle 18 in the subsequent process. The liquid-absorbing particle spraying device 14 quantitatively sprinkles liquid-absorbing particles onto the area where the adhesive 2 has just been sprayed. The liquid-absorbing particles are adhered and fixed by the adhesive 2, forming a layer 3 of liquid-absorbing particles distributed at intervals on the surface of the surface layer substrate. Areas where the adhesive 2 has not been sprayed are not covered with liquid-absorbing particles. The resulting composite surface layer 1 has a smooth surface and stable adhesion of liquid-absorbing particles, which can provide a substrate with a certain structural strength for the subsequent deposition of the first loose layer 4.

[0033] It should be noted that the composite surface layer 1 prepared by the two methods in step S2 above is in a pre-formed state. The surface layer substrate and the liquid-absorbing particles are initially positioned by the cohesion between fibers or adhesives, and a completely stable bond structure is not yet formed. Both need to be heated in the heating chamber 16 along with the core in step S6. After the low-melting-point fiber sheath in the mixed fibers melts, stable bonding points are formed between the surface layer substrate fibers and the liquid-absorbing particles, and finally, the formed composite surface layer 1 is obtained.

[0034] The two composite surface layer forming methods mentioned above can be selected according to the actual configuration of the production line and are suitable for processing needs of different core structures.

[0035] As one of the preferred embodiments of the present invention, the mixing chamber of the fourth molding equipment is provided with an upper set of dispersing rollers and a lower set of dispersing rollers distributed vertically. The mixed material entering the mixing chamber of the fourth molding equipment is dispersed and mixed twice by the upper set of dispersing rollers and the lower set of dispersing rollers.

[0036] Specifically, the fourth forming device 20 has the same structure as the first forming device 8, the second forming device 9, and the third forming device 10. It also has a mixing chamber 11 and a negative pressure chamber 12. The mixing chamber 11 contains two sets of dispersing rollers arranged vertically. The material entering the mixing chamber 11 of the fourth forming device 20 is first initially dispersed by the upper set of dispersing rollers, and then further dispersed by the lower set of dispersing rollers, ensuring the fibers are fully loosened and that the particles and fibers are evenly mixed when liquid is added. Under the airflow guidance of the negative pressure chamber 12, the dispersed material is evenly deposited on the surface of the forming mesh belt 13, forming a uniformly thick surface substrate.

[0037] As one of the preferred embodiments of the present invention, steps S3, S4 and S5 respectively use a first molding device, a second molding device and a third molding device to perform negative pressure airflow molding processing; the mixing chambers of the first molding device, the second molding device and the third molding device are all provided with an upper group of dispersing rollers and a lower group of dispersing rollers distributed vertically, and the mixed materials entering the mixing chambers of the first molding device, the second molding device and the third molding device are all dispersed and mixed twice by the upper group of dispersing rollers and the lower group of dispersing rollers.

[0038] The mixing chambers 11 of the first forming equipment 8, the second forming equipment 9, and the third forming equipment 10 are all equipped with upper and lower dispersing roller groups distributed vertically. Materials entering the corresponding mixing chambers 11 are first dispersed by the upper dispersing roller group, and then dispersed and mixed a second time by the lower dispersing roller group. These two dispersing processes effectively break up any clumps in the mixed fibers, ensuring the fibers remain fluffy and uniform. For the first forming equipment 8 and the second forming equipment 9, which incorporate liquid absorbers, this also ensures thorough mixing of the liquid absorbers with the mixed fibers, preventing agglomeration and localized accumulation of the liquid. The material after these two dispersing processes can be uniformly discharged under negative pressure airflow, ensuring uniform thickness and component distribution of each fluffy layer after airflow forming. This ensures consistent performance across all areas of the formed core, while also guaranteeing that the fluffy bottom layer 6 formed by the third forming equipment 10 has uniform fluffiness.

[0039] Specifically, step S5 includes: conveying a portion of the mixed fibers to the mixing chamber of the third forming equipment for mixing, and then entering the negative pressure chamber of the third forming equipment, where the mixed fibers are air-formed on the surface of the forming mesh belt to form a fluffy bottom layer.

[0040] As one of the preferred embodiments of the present invention, step S3 specifically includes: feeding a portion of the mixed fibers into the mixing chamber of the first forming device, adding absorbent liquid and mixing evenly; the forming mesh belt carrying the composite surface layer into the negative pressure chamber below the mixing chamber, the discharge port of the mixing chamber facing the negative pressure chamber is provided with the baffle to cover the non-forming area, the baffle is close to the composite surface layer below, and airflow forming is performed under the action of negative pressure, the mixed materials formed by the mixed fibers and absorbent liquid are divided into two streams and deposited in the area of ​​the composite surface layer that is not covered, forming the first fluffy layer blocks that are spaced apart from each other.

[0041] Specifically, the mixed fibers are fed into the mixing chamber 11 of the first forming device 8, and absorbent liquid is added. The material is first initially dispersed by the upper set of dispersing rollers in the mixing chamber 11, and then further mixed by the lower set of dispersing rollers to fully loosen the fibers and mix them evenly with the absorbent liquid. The forming mesh belt 13 carries the formed composite surface layer 1 at a constant speed into the negative pressure chamber 12 area below the mixing chamber 11. A baffle 18 is fixed at the discharge port of the mixing chamber 11 facing the negative pressure chamber 12. The baffle 18 is set in the non-forming area of ​​the composite surface layer 1, close to the surface of the composite surface layer 1 but without direct contact. A negative pressure airflow is generated in the negative pressure chamber 12, which drives the mixed fibers and absorbent liquid in the mixing chamber to move downward. The mixed material can only fall through the discharge area not covered by the baffle 18, and is evenly deposited in the corresponding area of ​​the composite surface layer 1, finally forming mutually spaced first fluffy layer 4 blocks on the surface of the composite surface layer 1.

[0042] As one of the preferred embodiments of the present invention, step S4 specifically includes: feeding a portion of the mixed fibers into the mixing chamber of the second molding device, adding absorbent liquid and mixing evenly; the molding mesh belt carrying the first composite into the negative pressure chamber below the mixing chamber, the discharge port of the mixing chamber facing the negative pressure chamber is provided with the baffle to cover the corresponding non-molding area, the baffle is close to the lower composite surface layer, and airflow molding is performed under the action of negative pressure, the composite material formed by the mixed fibers and absorbent liquid is divided into two strands and deposited in the uncovered area of ​​the first fluffy layer block, forming a second fluffy layer block that overlaps with the first fluffy layer block and is distributed at intervals to each other, and the area where no fibers are deposited constitutes a guide channel.

[0043] Both the mixing chamber 11 of the first molding device 8 and the second molding device 9 have baffles 18 installed at the material inlet facing the negative pressure chamber 12. The installation position of the baffles 18 corresponds to the spaced spraying area of ​​the adhesive 2 on the composite surface layer 1. The baffles 18 are close to the surface of the composite surface layer 1 but do not directly contact it. The width of the baffles 18 is consistent with the spacing of the adhesive 2 spraying, which can completely cover the area of ​​the composite surface layer 1 where the adhesive 2 is not sprayed. The mixed fibers and liquid-absorbing mixed materials can only be sprayed out from the area not covered by the baffles 18.

[0044] Negative pressure devices are connected to the negative pressure chambers 12 of the mixing chambers 11 of the first molding equipment 8 and the second molding equipment 9. Under the guidance of the negative pressure airflow in the negative pressure chamber 12, the mixed material in the mixing chamber 11 of the first molding equipment 8 falls evenly onto the non-covered area of ​​the liquid-absorbing layer 3 on the composite surface layer 1, forming the first fluffy layer 4. When the molding mesh belt 13 carries the composite surface layer to the bottom of the second molding equipment 9, the baffle 18 at the material drop port of the second molding equipment 9 is aligned with the position of the previous baffle 18, and the mixed material also falls onto the non-covered area, forming the second fluffy layer 5 that overlaps with the first fluffy layer 4. When the baffle 18 is removed, the areas on the two fluffy layers that are not filled with mixed material form a continuous through-type trough structure, which is the guide channel 7 of the core.

[0045] In one preferred embodiment of the present invention, the width of the baffle 18 is the same as the spacing of the adhesive spraying interval, both being 10-30mm, and the thickness of the baffle 18 is 5-10mm.

[0046] The width of the baffle 18 is the same as the spacing of the adhesive 2 sprayed intermittently on the composite surface layer 1 by the adhesive spraying device 15, both being 10-30mm. This ensures that the baffle 18 completely covers the areas on the composite surface layer 1 where no adhesive 2 has been sprayed, ensuring that the molded guide channel 7 corresponds to the position of the adhesive-free area. The thickness of the baffle 18 is 5-10mm, matching the molding thickness of the first fluff layer 4 and the second fluff layer 5, preventing the baffle 18 from being too thick and hindering the spread of the mixed material, or too thin and failing to form the depth of the guide channel 7 that meets the usage requirements.

[0047] As one of the preferred embodiments of the present invention, in step S6, the temperature inside the heating box is 110-140°C, and the relative moisture content of the composite formed by the fluffy bottom layer and the second composite is 6-10%.

[0048] The composite core is then placed in a heating chamber 16 for heat treatment. The temperature inside the heating chamber 16 is controlled between 110-140℃. This temperature range matches the melting point of the cortex of the low-melting-point fiber used in the core, allowing the cortex of the low-melting-point fiber to melt and form bonding points with the surrounding plant fibers and liquid absorbent material. This fixes the layered, fluffy structure of the core and the shape of the guide channels 7, preventing delamination and material spillage during subsequent processing or use. During the heating process, the relative moisture content of the composite formed by the fluffy bottom layer 6 and the second composite is controlled at 6-10%, ensuring that the core has suitable softness and preventing the core from becoming brittle and the fibers from breaking due to excessively low moisture content.

[0049] As one of the preferred embodiments of the present invention, in step S1, the low melting point fiber is selected from at least one of ES fiber and PE / PET core-sheath fiber, the melting point of the low melting point fiber sheath is 110-140℃, and the plant fiber is selected from at least one of wood pulp fiber, cotton fiber, bamboo pulp fiber, and hemp fiber. The absorbent liquid is selected from any one or more of SAP particles, cross-linked polyacrylamide water-absorbing resin particles, cross-linked polyvinyl alcohol water-absorbing particles, polyglutamic acid cross-linked particles, and superabsorbent fibers.

[0050] The low-melting-point fiber is selected from at least one of ES fiber and PE / PET core-sheath fiber. The proportion of low-melting-point fiber in the mixed fiber is 10-50%. The melting point of the sheath of the low-melting-point fiber is 110-140℃, which matches the heating temperature of the heating box 16. The low-melting-point fiber plays a skeleton role in the core structure. After being heated by the heating box 16, the sheath of the low-melting-point fiber melts and can form stable bonding points with the surrounding plant fibers and liquid absorbent, fixing the layered fluffy structure of the first fluffy layer 4, the second fluffy layer 5, and the fluffy bottom layer 6. At the same time, it maintains the forming shape of the guide groove 7, avoiding the problem of structural collapse and layering of the core during subsequent processing or water absorption, and ensuring the stability of the internal pore structure of the core.

[0051] Plant fibers are selected from at least one of wood pulp fiber, cotton fiber, bamboo pulp fiber, and hemp fiber, accounting for 50-90% of the blended fibers. They function as liquid conductors within the core, while also contributing to its biodegradability to some extent. Plant fibers possess excellent hydrophilicity and capillary action, forming continuous liquid-conducting channels within each loose layer. This allows urine to flow smoothly within and between layers. Combined with the gradient distribution of liquid absorption within the core, urine is quickly dispersed throughout the entire core area, preventing localized liquid accumulation. The stable framework formed by plant fibers and low-melting-point fibers prevents blockage of the liquid-conducting channels after absorbing water and swelling, improving the core's absorption efficiency and reducing backflow.

[0052] The liquid absorbent material is selected from any one or more of SAP particles, cross-linked polyacrylamide water-absorbing resin particles, cross-linked polyvinyl alcohol water-absorbing particles, polyglutamic acid cross-linked particles, and superabsorbent fibers; Specifically, polyacrylate superabsorbent fiber can be selected as the superabsorbent fiber. The superabsorbent fiber can quickly swell and lock in the liquid after it comes into contact with the liquid. It has a strong liquid retention capacity and can reduce the amount of backflow during the use of the core. The superabsorbent liquid is formed by the airflow of the mixed fibers and can be evenly dispersed in the corresponding fluffy layer block, so that the core can get a good absorption effect.

[0053] The above description is only a preferred embodiment of the present invention. It should be noted that those skilled in the art can make several improvements and modifications without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for manufacturing an absorbent core with a layered, fluffy fiber structure, characterized in that, Includes the following steps: S1. Low-melting-point fibers and plant fibers are opened and mixed to obtain blended fibers; S2. A portion of the mixed fibers is processed to obtain a composite surface layer, the composite surface layer comprising a surface layer substrate and an absorbent layer; S3. After mixing a portion of the mixed fibers with the absorbent liquid in the first molding equipment, negative pressure airflow molding is performed so that the mixed material formed by the mixed fibers and the absorbent liquid is split and deposited on the composite surface layer by the baffles set at the discharge port of the mixing chamber of the first molding equipment, forming mutually spaced first fluffy layer blocks, and obtaining the first composite. S4. After mixing a portion of the mixed fibers with the absorbent liquid in the second molding equipment, negative pressure airflow molding is performed so that the mixed material formed by the mixed fibers and the absorbent liquid is split and deposited on the first fluffy layer block of the first composite by the baffle set at the discharge port of the mixing chamber of the second molding equipment, forming a second fluffy layer block that overlaps with the first fluffy layer block and is spaced apart from each other, thus obtaining the second composite. S5. A portion of the mixed fibers is molded under negative pressure airflow to obtain a fluffy bottom layer; S6. After combining the fluffy bottom layer with the second composite, the core is heated, cooled and shaped, and then cut to obtain the absorbent core.

2. The method for manufacturing an absorbent core with a layered, fluffy fiber structure according to claim 1, characterized in that, The liquid absorption content in the first fluffy layer block is greater than or equal to the liquid absorption content in the second fluffy layer block.

3. The method for manufacturing an absorbent core with a layered, fluffy fiber structure according to claim 1, characterized in that, In step S2, the composite molding equipment includes a fourth molding device and a liquid spraying device arranged sequentially along the material feeding direction, and the composite surface layer is formed in the following manner: After the mixed fibers are transported to the mixing chamber of the fourth forming equipment for mixing, they enter the negative pressure chamber of the fourth forming equipment. Under the action of negative pressure, the mixed fibers are air-formed on the surface of the forming mesh belt in the negative pressure chamber of the fourth forming equipment to form the surface substrate. The liquid-absorbing spraying device applies liquid-absorbing particles at intervals to the surface substrate to form a liquid-absorbing layer that is spaced apart from each other on the surface of the surface substrate, thereby obtaining a composite surface layer.

4. The method for manufacturing an absorbent core with a layered, fluffy fiber structure according to claim 3, characterized in that, In step S2, the composite molding equipment further includes a spraying adhesive device disposed between the fourth molding device and the liquid spraying device, and the composite surface layer is formed in the following manner: After the mixed fibers are transported to the mixing chamber of the fourth forming equipment for mixing, they enter the negative pressure chamber of the fourth forming equipment. Under the action of negative pressure, the mixed fibers are air-formed on the surface of the forming mesh belt in the negative pressure chamber of the fourth forming equipment to form the surface substrate. The adhesive is sprayed at intervals onto the upper surface of the surface substrate by the adhesive spraying device; The liquid-absorbing spraying device applies liquid-absorbing particles to the area where the adhesive is sprayed, so as to form a liquid-absorbing layer that is spaced apart from each other on the surface of the surface layer substrate, thereby obtaining a composite surface layer.

5. A method for manufacturing an absorbent core with a layered, fluffy fiber structure according to claim 2 or 3, characterized in that, The mixing chamber of the fourth molding equipment is equipped with an upper set of dispersing rollers and a lower set of dispersing rollers that are arranged vertically. The mixed material entering the mixing chamber of the fourth molding equipment is dispersed and mixed twice by the upper set of dispersing rollers and the lower set of dispersing rollers.

6. A method for manufacturing an absorbent core with a layered, fluffy fiber structure according to claim 1, characterized in that, Steps S3, S4, and S5 respectively employ a first forming device, a second forming device, and a third forming device to perform negative pressure airflow forming processing; each of the first forming device, the second forming device, and the third forming device is equipped with an upper set of dispersing rollers and a lower set of dispersing rollers arranged vertically within its mixing chamber; the mixed materials entering the mixing chamber of the first forming device, the second forming device, and the third forming device are all dispersed and mixed twice by the upper set of dispersing rollers and the lower set of dispersing rollers; Specifically, step S5 includes: conveying a portion of the mixed fibers to the mixing chamber of the third forming equipment for mixing, and then entering the negative pressure chamber of the third forming equipment, where the mixed fibers are air-formed on the surface of the forming mesh belt to form a fluffy bottom layer.

7. A method for manufacturing an absorbent core with a layered, fluffy fiber structure according to claim 6, characterized in that, Step S3 specifically includes: feeding a portion of the mixed fibers into the mixing chamber of the first forming device, adding absorbent liquid and mixing evenly; the forming mesh belt carrying the composite surface layer into the negative pressure chamber below the mixing chamber, the discharge port of the mixing chamber facing the negative pressure chamber is provided with the baffle to cover the non-forming area, the baffle is close to the composite surface layer below, and airflow forming is performed under the action of negative pressure, the mixed material formed by the mixed fibers and absorbent liquid is divided into two streams and deposited in the area of ​​the composite surface layer that is not covered, forming the first loose layer blocks that are spaced apart.

8. A method for manufacturing an absorbent core with a layered, fluffy fiber structure according to claim 6, characterized in that, Step S4 specifically includes: feeding a portion of the mixed fibers into the mixing chamber of the second molding device, adding absorbent liquid and mixing evenly; the molding mesh belt carrying the first composite into the negative pressure chamber below the mixing chamber, the discharge port of the mixing chamber facing the negative pressure chamber is provided with the baffle to cover the corresponding non-molding area, the baffle is close to the lower composite surface layer, and airflow molding is performed under the action of negative pressure, the composite material formed by the mixed fibers and absorbent liquid is divided into two strands and deposited in the uncovered area of ​​the first fluffy layer block, forming a second fluffy layer block that overlaps with the first fluffy layer block and is distributed at intervals to each other, and the area where no fibers are deposited constitutes a guide channel.

9. A method for manufacturing an absorbent core with a layered, fluffy fiber structure according to claim 1, characterized in that, In step S6, the temperature inside the heating box is 110-140℃, and the relative moisture content of the composite formed by the fluffy bottom layer and the second composite is 6-10%.

10. A method for manufacturing an absorbent core with a layered, fluffy fiber structure according to claim 1, characterized in that, The low-melting-point fiber is selected from at least one of ES fiber and PE / PET core-sheath fiber, and the melting point of the low-melting-point fiber sheath is 110-140℃. The plant fiber is selected from at least one of wood pulp fiber, cotton fiber, bamboo pulp fiber, and hemp fiber. The absorbent liquid is selected from any one or more of SAP particles, cross-linked polyacrylamide water-absorbing resin particles, cross-linked polyvinyl alcohol water-absorbing particles, polyglutamic acid cross-linked particles, and superabsorbent fibers.

Images