An enhanced absorbent core sanitary napkin and a production process thereof

Abstract

The application relates to the technical field of sanitary napkin production and discloses an enhanced sanitary napkin with an absorbing core, which comprises, from top to bottom, a surface layer, a flow guide composite layer, a water locking core and a leakage prevention bottom layer; the flow guide composite layer comprises foam, the upper surface of the foam is provided with an accommodating groove, a flow guide framework is arranged in the accommodating groove, the surface of the flow guide framework is provided with a flow guide groove, a plurality of anchoring columns are arranged on the bottom surface of the flow guide framework in a spaced mode, the anchoring columns pass through the bottom of the accommodating groove and are inserted into the water locking core, and the water locking core and the water locking core are mechanically interlocked; the water locking core is provided with, from top to bottom, a flash absorption layer, a main liquid storage layer and an anti-reverse osmosis layer. The application improves the utilization rate of the whole sanitary napkin absorbing area.

Description

Technical Field

[0001] This invention relates to the field of sanitary napkin manufacturing technology, and in particular to a sanitary napkin with an enhanced absorbent core and its manufacturing process. Background Technology

[0002] Sanitary napkins, as products worn directly against the skin during menstruation, are made of cotton, non-woven fabric, pulp, or a composite of these materials, forming a polymer and polymer composite paper. The side design is primarily to prevent leakage. The adhesive backing is made of a waterproof material, retaining menstrual blood within the pad to absorb the flow from the vagina during menstruation. Current sanitary napkin products face the following technical bottlenecks: 1. Uneven liquid diffusion within the core results in low absorption area utilization and a tendency for leakage; 2. Absorption speed and water-locking ability are mutually restrictive and difficult to balance; 3. Weak bonding between functional layers leads to easy delamination and detachment during use. Summary of the Invention

[0003] In view of this, the purpose of the present invention is to provide an enhanced absorbent core sanitary napkin and its manufacturing process, so as to solve the problems mentioned in the background art.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: an enhanced absorbent core sanitary napkin, comprising, from top to bottom, a surface layer, a flow-guiding composite layer, a water-locking core, and a leak-proof bottom layer; the flow-guiding composite layer comprises foam, the upper surface of which has a receiving groove, a flow-guiding skeleton disposed within the receiving groove, a flow-guiding groove disposed on the surface of the flow-guiding skeleton, and a plurality of anchoring posts disposed at intervals on the bottom surface of the flow-guiding skeleton, the anchoring posts passing through the bottom of the receiving groove and inserted into the water-locking core, forming a mechanical interlock with the water-locking core; the water-locking core is respectively configured from top to bottom as an instant absorption layer, a main liquid storage layer, and an anti-backflow layer.

[0005] Furthermore, the flow-guiding skeleton is a leaf vein-like biomimetic structure, including a main support and multiple sub-supports, which radiate from the center of the sanitary napkin to the periphery and tail. The longitudinal cross-section of the main support and the sub-supports is a trapezoidal structure, and the connection angle between the main support and the sub-supports is a rounded transition. The surfaces of the main support and the sub-supports are provided with flow-guiding grooves, and multiple capillary pores are opened on the side walls of the flow-guiding grooves. The top of the flow-guiding skeleton is slightly lower than the top of the foam.

[0006] Furthermore, the material of the flow guide skeleton is polyether-type TPU with a Shore hardness of 65A, and its surface is hydrophilicated.

[0007] Furthermore, the foam is a hydrophilic polyurethane foam with an open area ratio of ≥95%, the surface layer is made of soft non-woven fabric, and the leak-proof bottom layer is made of a microporous breathable membrane.

[0008] Furthermore, the instant absorption layer is formed by mixing SAP particles with fluff pulp, and the main storage layer and the anti-reverse osmosis layer are formed by mixing SAP particles with hot melt adhesive fibers. Each layer is coated and hot-pressed to form a whole. The particle size of the SAP particles in each layer is distributed in a gradient from large to small from top to bottom.

[0009] Furthermore, it also includes an elastic edge strip, which is fixed to both sides of the sanitary napkin by ultrasonic welding. The elastic edge strip is made by mixing TPU fibers and absorbent cotton in a mass ratio of 2:1 and shaping it using a needle punching process.

[0010] This invention also proposes a manufacturing process for an enhanced absorbent core sanitary napkin, comprising the following steps:

[0011] S1: Place the leak-proof bottom layer into the lower mold cavity of the sanitary napkin mold, and fix the edges of the leak-proof bottom layer with vacuum adsorption to ensure that it is flat and does not shift.

[0012] S2: SAP composite powder is applied sequentially from bottom to top on the leak-proof bottom layer to form an anti-reverse osmosis layer, a main storage liquid layer, and an instantaneous absorption layer using a multi-channel powder spreading device; during the coating process, the powder is vacuum-adsorbed through the leak-proof bottom layer to prevent powder displacement.

[0013] S3: Place the prefabricated flow-guiding composite layer entirely on the powder, ensuring that the anchoring post is inserted into the powder;

[0014] S4: Cover the surface layer material on top of the composite flow guide layer, so that all materials are ready to be stacked in the lower mold cavity;

[0015] S5: The upper mold moves downward, causing the contoured groove on the working surface of the upper mold to fit into the guide skeleton, and the layers are integrated and composited through hot pressing.

[0016] S6: Remove the core blank from the mold, weld the elastic locking strip by ultrasonic welding, and perform final shape cutting to obtain the finished product.

[0017] Furthermore, the mold cavity of the lower mold includes a sanitary napkin main mold cavity and a side wing mold cavity. The bottom depth of the side wing mold cavity is less than the bottom depth of the sanitary napkin main mold cavity, and the two are sloped. A vacuum adsorption system is provided below the mold cavity, including an annular edge sealing cavity for fixing the bottom material and a main adsorption cavity for stabilizing the powder.

[0018] Furthermore, the upper mold working surface is provided with a forming part, which is arranged around the inner edge of the mold cavity and has a separating protrusion between the side wing and the sanitary napkin body; the upper mold working surface is provided with a contoured groove inside the forming part that matches the shape of the guide skeleton, and an elastic buffer pad is embedded in the contoured groove.

[0019] Furthermore, heating rods are provided inside both the upper and lower molds. The upper mold has multiple positioning holes, and the surface of the lower mold has multiple positioning pins. The positioning holes and positioning pins are inserted and cooperate to achieve precise alignment between the upper and lower molds. Beneficial effects

[0020] Compared with the prior art, the present invention has at least the following advantages:

[0021] 1. This invention incorporates a leaf vein-like biomimetic structure, a flow-guiding skeleton with surface channels and mushroom-shaped anchoring posts at the bottom, into a receiving groove within a high-porosity hydrophilic foam, forming a composite functional layer. The foam's three-dimensional open-cell structure achieves breathability and instant absorption, while the flow-guiding skeleton's directional channels and capillaries address localized saturation issues. The mushroom-shaped anchoring posts of the flow-guiding skeleton insert water-locking core powder, which is then cured after hot pressing, forming a mechanical interlock that effectively solves the problem of interlayer separation. The elastic skeleton and foam material ensure wearing comfort and a snug fit.

[0022] 2. Some liquid is guided by the surface nonwoven fabric into the three-dimensional open-cell network of the hydrophilic foam. The liquid is first captured by the foam and then rapidly diffuses laterally within its three-dimensional network. A large amount of liquid can directly enter the guide channels of the guide frame through the surface layer for longitudinal main transport and lateral branch transport, avoiding local saturation. When the liquid volume in the guide channels is large, it is diverted through capillary pores to the foam on both sides and finally absorbed by the absorbent core. This invention improves the liquid absorption speed, diffusion uniformity, and utilization rate of the absorbent core, increasing the utilization rate of the entire sanitary napkin's absorbent area. It effectively prevents local saturation and liquid backflow, thus keeping the surface dry.

[0023] 3. The absorbent core's instant-absorption layer achieves instant absorption, capturing liquid from the guiding composite layer immediately, keeping the sanitary napkin surface dry and preventing liquid retention. The main liquid storage layer provides a large surface area and volume for storing liquid, serving as the primary liquid storage area. The anti-backflow layer effectively resists external pressure, preventing liquid backflow. The absorbent core, combined with the internal structure of the foam, enables the sanitary napkin to absorb quickly and has excellent water-locking ability. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the structure of the sanitary napkin of the present invention.

[0025] Figure 2 This is a schematic diagram of the exploded structure of the sanitary napkin of the present invention.

[0026] Figure 3 This is a schematic diagram of the flow guide frame of the present invention.

[0027] Figure 4 For the present invention Figure 3 A magnified structural diagram of part A.

[0028] Figure 5 This is a schematic diagram of the interlayer structure of the present invention.

[0029] Figure 6 This is a schematic diagram of the water-locking core of the present invention.

[0030] Figure 7 This is a schematic diagram of the lower mold structure used in the production of sanitary napkins according to the present invention.

[0031] Figure 8 For the present invention Figure 7 A schematic diagram of the back structure.

[0032] Figure 9 This is a schematic diagram of the upper mold structure used in the production of sanitary napkins according to the present invention.

[0033] The diagram is labeled as follows: 1-Sanitary napkin body; 2-Side wing; 3-Elastic locking strip; 4-Guiding skeleton; 40-Main support; 41-Sub-support; 42-Guiding groove; 43-Capillary pore; 44-Anchoring post; 5-Surface layer; 6-Leak-proof bottom layer; 7-Guiding composite layer; 8-Water-locking core; 80-Instant absorption layer; 81-Main liquid storage layer; 82-Anti-backflow layer; 9-Accommodation groove; 10-Lower mold; 11-Mold cavity; 110-Sanitary napkin body mold cavity; 111-Side wing mold cavity; 12-Outer vacuum adsorption hole; 13-Main body vacuum adsorption hole; 14-Positioning post; 15-Annular edge sealing cavity; 16-Outer vacuum connector; 17-Main body adsorption cavity; 18-Main body vacuum connector; 19-Upper mold; 20-Positioning hole; 21-Forming part; 22-Separating protrusion; 23-Contouring groove; 24-Heating rod. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of the present invention clearer, a detailed description is provided below in conjunction with the accompanying drawings and specific embodiments. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0035] It should be noted that when an element is referred to as being "fixed to" another element, it can be directly on the other element or there may be an intervening element. When an element is referred to as being "connected to" another element, it can be directly connected to the element or there may be an intervening element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0036] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0037] See Figures 1-9 This embodiment proposes an enhanced absorbent core sanitary napkin, which includes a surface layer 5, a diversion composite layer 7, a water-locking core 8, and a leak-proof bottom layer 6 arranged sequentially from top to bottom; the surface layer 5 is made of pure cotton hydrophilic non-woven fabric, and the leak-proof bottom layer 6 is made of microporous breathable PE film. The flow-guiding composite layer 7 includes foam, with a receiving groove 9 on the upper surface of the foam. A flow-guiding skeleton 4 is disposed within the receiving groove 9, and a flow-guiding groove 42 is disposed on the surface of the flow-guiding skeleton 4, which is close to the surface layer 5. Multiple anchoring posts 44 are spaced apart on the bottom surface of the flow-guiding skeleton 4. The anchoring posts 44 have a mushroom-shaped structure and pass through the bottom of the receiving groove 9, inserting into the water-locking core 8. The material of the water-locking core 8 encapsulates the anchoring posts 44, forming a mechanical interlock with the water-locking core 8. The foam is made of hydrophilic polyurethane foam with an open porosity ≥95%, which can instantly capture liquid and quickly transport it to the water-locking core 8 through the three-dimensional mesh structure inside the foam, either horizontally or vertically. The three-dimensional open structure of the foam itself has breathable channels, which, combined with the breathable PE membrane of the leak-proof bottom layer 6, effectively reduces stuffiness.

[0038] The flow-guiding skeleton 4 is made of polyether-type thermoplastic polyurethane (TPU) with a Shore hardness of 65A, and its surface has been hydrophilically treated. The flow-guiding skeleton has a leaf-vein-like biomimetic structure, including a main support 40 and multiple sub-supports 41, radiating from the center of the sanitary napkin to the periphery and tail. The longitudinal cross-section of the main support 40 and the sub-supports 41 is trapezoidal. Specifically, the top width of the main support 40 is 1.8mm, and the bottom width is 1.2mm; the top width of the sub-supports 41 is 1mm, and the bottom width is 0.6mm. The trapezoidal structure can disperse stress during bending, avoiding localized stiffness. The connection angle between the main support 40 and the sub-supports 41 is a rounded transition.

[0039] Both the main support 40 and the sub-support 41 are provided with flow guide grooves 42 to provide a directional flow path for the liquid and quickly guide the liquid to diffuse in all directions. Multiple capillary pores 43 are formed on the side walls of the flow guide grooves 42. The top of the flow guide frame 4 is slightly lower than the top of the foam. The liquid in the flow guide grooves 42 flows outward through the capillary pores 43 and is quickly absorbed by the foam, expanding the effective absorption area. Simultaneously, the liquid is guided to the water-locking core 8 through the anchoring posts 44 at the bottom of the frame.

[0040] In this embodiment, the surface layer 5 is 0.2mm thick, the water-locking core is 2mm thick, the leak-proof bottom layer 6 is 0.2mm thick, and the flow-guiding composite layer 7 is 1.5mm thick. The foam is 1mm thick, with a recessed groove depth of 0.8mm. The flow-guiding skeleton 4 is 0.7mm thick, with the top of the foam extending 0.1mm above the flow-guiding skeleton. The flow-guiding groove 42 is 0.3mm deep, the main support flow-guiding groove is 1.1mm wide, and the sub-support flow-guiding groove is 0.7mm wide. The capillary diameter is 0.12mm, achieved through laser drilling, with a 3.5mm spacing between adjacent capillary pores. The anchoring post 44 is 0.7mm high; the mushroom-shaped anchoring post's umbrella cap is 0.15mm high and has a top diameter of 0.5mm. The distance between the top of the umbrella cap and the bottom of the foam is 0.35mm, facilitating the entry of the water-locking core material into this gap to enclose the umbrella cap structure. The water-locking core material cools and solidifies, mechanically locking the umbrella cap and forming a strong anti-peeling force, effectively preventing interlayer delamination.

[0041] In this embodiment, the material of the guide frame 4 and the foam are both soft and elastic, allowing the entire sanitary napkin to easily bend with the body's curves without feeling hard.

[0042] It should be noted that in other embodiments, the sub-support 41 is not of a uniform width, but gradually narrows outward from the connection point with the main support, with rounded ends. Simultaneously, the guide channel also exhibits a structure that narrows from wide to narrow. The sub-support is wider near the main support, which can accommodate a large amount of liquid transported by the main support, preventing localized congestion; the gradual narrowing outward creates a pressure gradient, pushing the liquid quickly towards the edge of the sanitary napkin, rather than accumulating in the center. Furthermore, the narrowing at the tail of the sub-support makes its end more flexible and comfortable to wear.

[0043] In practice, the fabrication process of the flow-guiding composite layer 7 is as follows:

[0044] First, the flow guide frame 4 is prepared by precision injection molding. Then, capillary holes 43 are made on the side wall of the flow guide groove 42 of the flow guide frame 4 by laser drilling. Before the foam and the flow guide frame 4 are combined, a receiving groove 9 for embedding the body of the flow guide frame 4 is made in the foam. Then, an array of holes for passing through the anchor post 44 is precisely punched or drilled at the bottom of the receiving groove 9.

[0045] Secondly, during assembly and production, the flow guide frame 4 is precisely pressed into the receiving groove 9 of the foam, ensuring that each anchor post 44 protrudes from the corresponding hole. Ultrasonic spot welding is then performed along the edge of the flow guide frame 4 to achieve local micro-fusion between the foam and the frame, avoiding damage to the foam's open structure. Then, the foam and flow guide frame 4 are combined as a whole and hot-pressed with the water-locking core 8 material.

[0046] In a specific implementation of this invention, a portion of the liquid is guided by the nonwoven fabric of the surface layer 5 into the three-dimensional open-cell network of the hydrophilic foam. The liquid is first captured by the foam and then rapidly diffuses laterally within its three-dimensional network. A large amount of liquid can directly enter the guide channel 42 of the guide frame 4 through the surface layer 5 for longitudinal main transport and lateral branch transport, avoiding local saturation. When the liquid volume in the guide channel 42 is large, the liquid flows along the guide channel 42 while permeating outward through the capillary pores 43 on the side wall, and is rapidly absorbed by the foam, expanding the effective absorption area and avoiding local saturation.

[0047] The water-locking core 8 is configured from top to bottom as an instant absorption layer 80, a main liquid storage layer 81, and an anti-backflow layer 82. The instant absorption layer 80 is formed by mixing SAP particles with fluff pulp. The main liquid storage layer 81 and the anti-backflow layer 82 are formed by mixing SAP particles with a small amount of hot melt adhesive fibers. Each layer is coated and hot-pressed to form a whole, and the particle size of the SAP particles in each layer shows a gradient distribution from large to small from top to bottom. Among them, the instant absorption layer 80 is formed by mixing large-diameter SAP particles with fluff pulp to form a loose mesh structure. Liquid can quickly penetrate downwards and diffuse laterally to achieve instant absorption, capturing the liquid from the guide composite layer 7 in the first time, keeping the sanitary napkin surface dry and preventing liquid retention. The particle size of the SAP particles in this layer is 350μm. During production, the main liquid storage layer 81 uses medium-sized SAP particles with a particle size of 250μm, which are uniformly spread with a high coating amount. The moderate pore structure between the SAP particles ensures smooth liquid passage while providing a large surface area and volume for liquid storage, making it the main liquid storage area. When the instantaneous absorption layer 80 approaches saturation, its internal liquid concentration is higher than that of the main liquid storage layer 81 below. The liquid diffuses from the instantaneous absorption layer 80 to the low-concentration main liquid storage layer 81 and continues to seep downwards. The anti-backflow layer 82 uses smaller-sized SAP particles with a particle size of 150μm, which are formed by hot pressing to create a fine microporous structure. The dense microporous structure generates strong capillary force, keeping the liquid in the pores. At the same time, the high-density gel layer formed after the SAP absorbs water can effectively resist external pressure and prevent liquid backflow.

[0048] In this invention, the leak-proof bottom layer 6, corresponding to the main body area of ​​the water-locking core 8, undergoes laser perforation to create a small hole array with a diameter of 5-10 micrometers and a spacing of 20-30 micrometers between the holes. The hole diameter is smaller than the minimum SAP particle size of the water-locking core 8 (150 micrometers) to prevent powder leakage. The aforementioned laser-processed small hole array is completed during the PE film production roll-forming stage. The incoming material is a microporous breathable PE film roll with a pre-set small hole array, which is directly used in the sanitary napkin cutting process.

[0049] In the technical solution of this invention, the anchoring post 44 passes through the foam holes at the bottom of the receiving groove 9 and is fully inserted into the instantaneous absorption layer 80 of the water-locking core 8, ensuring that the water-locking core material tightly wraps the anchoring post cap while not damaging the liquid storage space of the main liquid storage layer. The anchoring posts are staggered: one is set every 5mm along the length of the main support, and one is set every 7mm along the length of the sub-support.

[0050] The present invention also includes an elastic locking strip 3, which is fixed to both sides of the sanitary napkin by ultrasonic welding. The elastic locking strip 3 is made by mixing TPU fibers and absorbent cotton in a mass ratio of 2:1 and shaping it by needle punching.

[0051] This invention also proposes a manufacturing process for an enhanced absorbent core sanitary napkin, comprising the following steps:

[0052] S1: The microporous breathable PE film is drawn out from the unwinding device and cut into single pieces by the cutting knife. The single piece of microporous breathable PE film is used as the leak-proof bottom layer. It is picked up by the vacuum suction cup robot and precisely laid in the lower mold cavity 11 of the sanitary napkin special mold. The edges of the leak-proof bottom layer 6 are fixed by vacuum adsorption to ensure that it is flat and without displacement.

[0053] S2: The three-channel powder spreading equipment has three independently controlled hoppers, each containing SAP powder for the instant absorption layer 80, the main liquid storage layer 81, and the anti-backflow layer 82. The powder spreading equipment scans and moves on the bottom material according to a preset program, precisely controlling the amount of powder applied to each layer. SAP powder is applied from bottom to top on the leak-proof bottom layer of the sanitary napkin to form the anti-backflow layer, the main liquid storage layer, and the instant absorption layer. The SAP powder for the instant absorption layer is a mixture of SAP particles and fluff pulp, while the SAP powder for the main liquid storage layer 81 and the anti-backflow layer 82 is a mixture of SAP particles and a small amount of hot melt adhesive fibers. At the same time, the laser-processed small hole array in the main area of ​​the leak-proof bottom layer 6 is used to penetrate the PE film through the negative pressure suction generated by vacuum adsorption, and the powder is vacuum adsorbed to prevent the powder from shifting due to the airflow of the powder spreading machine or its own weight.

[0054] S3: The prefabricated flow-guiding composite layer is placed on the powder by a robot according to the preset position coordinates, ensuring that the anchoring post is inserted into the powder;

[0055] S4: The surface layer material is covered on the composite flow guiding layer by a robotic arm; so that the materials of the surface layer, flow guiding composite layer, water-locking core and leak-proof bottom layer are stacked in the lower mold cavity in the order from top to bottom, without misalignment or displacement.

[0056] S5: As the upper mold descends, the contoured groove first fits against the skeleton, and uniform pressure of approximately 0.1 MPa is applied through the silicone buffer pad. As the upper mold continues to descend, the surrounding forming part contacts the edge area of ​​the sanitary napkin, and the pressure gradually increases. Hot pressing is performed for 15 seconds at 115℃ and 0.3-0.4 MPa to achieve integrated lamination of all layers. During this process, the hot melt adhesive fibers in the main liquid storage layer 81 and the anti-backflow layer 82 melt and bond, while the fluff pulp fibers in the instant absorption layer 80 are also entangled and fixed. Simultaneously, the pressure forces the water-locking core material to tightly wrap the anchor post 44, especially its mushroom-shaped cap structure. After cooling and curing, the flow-guiding composite layer 7 and the water-locking core 8 are firmly bonded together, mainly through mechanical interlocking combined with the bonding effect of the hot melt adhesive, providing excellent anti-delamination capability. When the water-locking core 8 material cures, it forms an effective mechanical interlock with the mushroom-shaped cap of the anchor post 44, improving the anti-vertical peeling performance of the flow-guiding composite layer 7 and the water-locking core 8, providing good anti-delamination capability. It should be noted that the amount of hot melt fiber and fluff pulp added is controlled between 5% and 15% of the SAP mass to ensure the strength of the sanitary napkin core without significantly affecting the liquid absorption rate.

[0057] S6: Demolding, remove the sanitary napkin, move it to the ultrasonic welding station, send the elastic locking strip to both sides of the sanitary napkin, weld the elastic locking strip by ultrasonic welding, and perform final shape cutting to obtain the finished product.

[0058] The lower mold 10 has a mold cavity 11 on its working surface. The mold cavity 11 includes a sanitary napkin main body mold cavity 110 and a side wing mold cavity 111. The bottom depth of the side wing mold cavity 111 is less than the bottom depth of the sanitary napkin main body mold cavity 110, and there is a sloping transition between the two, so that there is no step transition at the bottom of the two. At the same time, the powder is confined to the main body of the sanitary napkin and will not run to the side wing. A vacuum adsorption system is located below the mold cavity 11. This system is configured to provide different adsorption forces to the annular edge region and the main body region. It includes an annular edge sealing cavity 15 for fixing the bottom layer material and a main body adsorption cavity 17 for stabilizing the powder. Multiple peripheral vacuum adsorption holes 12 are provided between the annular edge sealing cavity 15 and the mold cavity 11. The annular edge sealing cavity 15 is connected to a peripheral vacuum connector 16, which in turn connects to a vacuum generator. The peripheral vacuum adsorption holes 12 adsorb the edge of the leak-proof bottom layer 6. Multiple arrayed main body vacuum adsorption holes 13 are provided between the main body adsorption cavity 17 and the mold cavity 11. The main body adsorption cavity 17 is connected to a main body vacuum connector 18, which in turn connects to another vacuum generator. When the vacuum generator is activated, the water-locking core powder laid on the sanitary napkin body is adsorbed through the main body vacuum adsorption holes 13, separated by the leak-proof bottom layer. These two independently controlled vacuum generators can apply different vacuum intensities to the annular edge sealing cavity 15 and the main body adsorption cavity 17, respectively. The annular edge sealing cavity 15 maintains a relatively high vacuum (-0.05MPa to -0.09MPa) to secure the leak-proof bottom layer 6; the main adsorption cavity 17 maintains a relatively low and uniform vacuum (-0.03MPa to -0.07MPa) to stabilize the SAP powder while preventing over-adsorption or disruption of powder uniformity. The higher vacuum should be at least 0.02MPa higher than the lower vacuum to ensure differentiated adsorption effects.

[0059] The upper mold 19 has a protruding forming part 21 on its working surface, which has a raised structure consistent with the outer contour of the sanitary napkin. The forming part 21 is arranged around the inner edge of the mold cavity 11. The forming part 21 has a separating protrusion 22 between the side wings and the main body. The bottom shape of the forming part 21 and the separating protrusion 22 is adapted to the bottom shape of the mold cavity. During hot pressing, the forming part is pressed into the mold cavity, the forming part 21 is pressed against the edge of the sanitary napkin, and the separating protrusion 22 is pressed between the main body and the side wings of the sanitary napkin, pressing the surface layer and the leak-proof bottom layer together, so that a partition is formed between the main body and the side wings of the sanitary napkin, so that the water-locking core material of the main body of the sanitary napkin will not leak to the side wings. The upper mold 19 has a contoured groove 23 inside the forming part 21 on its working surface, which matches the shape of the guide frame 4. The contoured groove 23 is embedded with an elastic buffer pad made of silicone material. The cooperation of the contoured groove 23 and the elastic buffer pad applies uniform pressure to the guide frame 4, protecting the guide frame 4.

[0060] Heating rods are installed inside both the upper mold 19 and the lower mold 10. The heating rod of the lower mold is located inside the partition wall between the mold cavity 11, the main body adsorption cavity 17, and the annular edge sealing cavity 15, avoiding the vacuum adsorption holes opened in the partition wall. The upper mold 19 is provided with multiple positioning holes 20, and the surface of the lower mold is correspondingly provided with multiple positioning posts 14. The positioning holes 20 and positioning posts 14 are inserted and matched to make the upper mold and the lower mold precisely aligned. The upper mold and the lower mold are precisely aligned and pressed into the mold cavity of the lower mold, so that the edge of the sanitary napkin is pressed together.

[0061] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A process for the production of an enhanced absorbent core body sanitary napkin, characterized in that, The enhanced absorption core sanitary napkin comprises, from top to bottom, a surface layer, a flow guide composite layer, a water-locking core, and a leakage-proof bottom layer; the flow guide composite layer comprises foam, the upper surface of the foam is provided with a receiving groove, the receiving groove is provided with a flow guide framework, the surface of the flow guide framework is provided with a flow guide groove, the flow guide framework is a vein-like bionic structure, and comprises a main support and a plurality of branch supports; the main support and the branch supports radiate from the center of the sanitary napkin to the periphery and the tail; the longitudinal section of the main support and the branch supports is in trapezoidal structure, and the connection angle of the main support and the branch supports is in arc-shaped transition; the surface of the main support and the branch supports is provided with a flow guide groove, the two side walls of the flow guide groove are provided with a plurality of capillary holes, and the top of the flow guide framework is slightly lower than the top of the foam; the bottom surface of the flow guide framework is provided with a plurality of anchoring columns at intervals, the anchoring columns pass through the bottom of the receiving groove and are inserted into the water-locking core, and the water-locking core is formed in mechanical interlocking with the water-locking core; the water-locking core is provided with, from top to bottom, an instant absorption layer, a main liquid storage layer, and an anti-back seepage layer; and the process comprises the following steps: S1: The leakage-proof bottom layer is laid in the lower mold cavity of the special mold for the sanitary napkin, the edges of the leakage-proof bottom layer are fixed by vacuum adsorption to ensure that the leakage-proof bottom layer is flat and does not shift; S2: The SAP composite powder of the anti-back seepage layer, the main liquid storage layer, and the instant absorption layer is coated on the leakage-proof bottom layer from bottom to top by using a multi-channel powder laying device; during the coating process, the powder is vacuum adsorbed through the leakage-proof bottom layer to prevent the powder from shifting; S3: The prefabricated flow guide composite layer is placed on the powder as a whole to ensure that the anchoring columns are inserted into the powder; S4: The surface layer material is covered on the composite flow guide layer to make all the materials ready for layering in the lower mold cavity; S5: The upper mold is lowered to make the profiling groove provided on the working surface of the upper mold fit the flow guide framework, and the layers are integrated by hot pressing; S6: The core embryo is taken out of the mold, the elastic lock edge strip is welded by ultrasonic waves, and the final shape is cut to obtain the finished product.

2. A process for the production of an enhanced absorbent core sanitary napkin as claimed in claim 1, wherein, The material of the flow guide framework is polyether TPU with a Shore hardness of 65A, and the surface thereof is treated by hydrophilization.

3. A process for the production of an enhanced absorbent core sanitary napkin as claimed in claim 1, wherein, The foam is hydrophilic polyurethane foam with an opening rate of greater than or equal to 95%, the surface layer is made of cotton-soft non-woven fabric, and the leakage-proof bottom layer is made of a microporous breathable film.

4. A process for the production of an enhanced absorbent core sanitary napkin as claimed in claim 1, wherein, The instant absorption layer is formed by mixing SAP particles and fluff pulp, and the main liquid storage layer and the anti-back seepage layer are formed by mixing SAP particles and hot melt adhesive fibers, and the layers are integrated by coating and hot pressing curing; the particle sizes of the SAP particles in each layer are distributed in a gradient from large to small from top to bottom.

5. A process for the production of an enhanced absorbent core sanitary napkin as claimed in claim 1, wherein, An elastic lock edge strip is further included, the elastic lock edge strip is fixed on both sides of the sanitary napkin by ultrasonic welding, the elastic lock edge strip is made of TPU fibers and water-absorbing swelling cotton mixed at a mass ratio of 2:1, and is shaped by needle punching process.

6. A process for the production of an enhanced absorbent core sanitary napkin as claimed in claim 1, wherein, The mold cavity of the lower mold comprises a sanitary napkin main body mold cavity and a side wing mold cavity, the bottom depth of the side wing mold cavity is less than that of the sanitary napkin main body mold cavity, and the two are transitioned in a slope shape; a vacuum adsorption system is arranged below the mold cavity, and comprises a ring-shaped edge sealing cavity for fixing the bottom layer material and a main body adsorption cavity for stabilizing the powder.

7. A process for the production of an enhanced absorbent core sanitary napkin as claimed in claim 6, wherein, The upper die working surface is convexly provided with a forming part, the forming part is arranged around the inner edge of the cavity side, and a separation protrusion is arranged between the side wing and the sanitary napkin body; the upper die working surface is provided with a profiling groove matching the shape of the flow guide framework inside the forming part, and an elastic buffer pad is embedded in the profiling groove.

8. A process for the production of an enhanced absorbent core sanitary napkin as claimed in claim 1, wherein, The upper die and the lower die are both provided with heating rods, the upper die is provided with a plurality of positioning holes, the surface of the lower die is correspondingly provided with a plurality of positioning columns, and the positioning holes and the positioning columns are inserted and matched to realize the accurate alignment of the upper die and the lower die.

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