Sanitary napkin with non-deformable core body during movement and preparation method thereof

Abstract

The invention discloses a sanitary napkin with a non-deformable core body in motion, the sanitary napkin sequentially comprises a bottom film layer, a supporting layer, an absorbing layer, a flow guide layer and a skin-friendly layer from bottom to top, and a preparation method of the sanitary napkin with the non-deformable core body in motion comprises the following steps of S1, raw material preparation, S2, gradient core body preparation, S3, flow guide frame integration, S4, three-dimensional compounding, S5, edge strengthening and S6, quality detection and packaging. The upper-layer short fibers and the super absorbent resin are mixed according to a specific proportion, sudden menstrual blood outflow can be rapidly dealt with, discomfort or leakage risks caused by liquid retention are avoided, meanwhile, the lower-layer long fibers are interwoven with the super absorbent resin to form a stable structure, the surface can be kept dry even though jolting is conducted, and the health care effect is good. And skin problems caused by moisture are reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of sanitary napkins, and particularly to a sports-invariant core sanitary napkin and a preparation method thereof. Background Art

[0002] As an essential item for women during their menstrual periods, the quality and usage experience of sanitary napkins are crucial. With the pursuit of health and quality of life by modern women, more and more women also participate in various sports activities during their menstrual periods.

[0003] During the movement of women, the structural defects of the absorption layer in traditional sanitary napkins are obvious. Its single structural form is difficult to cope with the complex situations generated by the body during exercise. For example, the frequent movement and deformation of the body during exercise will cause the absorption layer to be subjected to forces in different directions, resulting in uneven distribution of internal materials and affecting the absorption effect. At the same time, the mixture of sweat and menstrual blood generated during exercise places higher requirements on the liquid treatment ability of the absorption layer, while the traditional absorption layer cannot efficiently process this mixed liquid, and is prone to problems such as side leakage and reverse osmosis, seriously affecting the usage experience and comfort of women during exercise.

[0004] Accordingly, this application proposes a sports-invariant core sanitary napkin and a preparation method thereof. Summary of the Invention

[0005] The purpose of the present invention is to solve the disadvantages existing in the prior art, and to propose a sports-invariant core sanitary napkin and a preparation method thereof.

[0006] In order to achieve the above purpose, the present invention adopts the following technical solutions: A sports-invariant core sanitary napkin and a preparation method thereof, which successively include a bottom film layer, a support layer, an absorption layer, a diversion layer and a skin-friendly layer from bottom to top; The edge of the bottom film layer forms a sealed edge with the absorption layer. The surface of the support layer is provided with pits adapted to the bottom of the absorption layer. The absorption layer is arranged as a double-layer gradient core. The upper layer of the absorption layer is a rapid absorption layer of short fibers mixed with superabsorbent resin, and the lower layer of the absorption layer is a water-locking layer of long fibers intertwined with superabsorbent resin. Columnar supports are evenly distributed between the upper layer and the lower layer of the absorption layer. The columnar supports vertically penetrate the upper and lower layers of the absorption layer. The surface of the diversion layer is provided with a non-woven fabric with diversion grooves. The bottom surface of the diversion layer is fiber-embedded with the upper layer of the absorption layer. The skin-friendly layer is connected to the diversion layer through spaced adhesive dots.

[0007] Preferably, the edge of the absorption layer is provided with a surrounding diversion frame higher than the surface of the core. The surrounding diversion frame is provided with an inclined diversion channel. The direction of the inclined diversion channel of the surrounding diversion frame forms an angle of 30°-60° with the longitudinal direction of the sanitary napkin.

[0008] Preferably, the top of the columnar support body is embedded in the bottom surface of the diversion layer, and there is a movable gap reserved between the bottom of the diversion layer and the pit of the support layer.

[0009] Preferably, the support layer and the bottom film layer are connected by grid glue, and the support layer and the absorption layer are locked by glue points around the support body.

[0010] Preferably, the depth of the diversion layer groove decreases from the edge to the center and forms a diversion slope with a high edge and a low center with the surrounding diversion frame.

[0011] A preparation method of a sports-invariant core sanitary napkin includes the following steps: S1. Raw material preparation: Prepare superabsorbent resins with different characteristics. Select those with small particle size and moderate liquid absorption ratio for the upper layer, and those with smaller particle size and higher liquid absorption ratio for the lower layer. Combine hydrophilic fibers with different lengths, store them in proportion, and prepare polyurethane elastomer as the columnar support body, hydrophilic polymer material as the surrounding diversion frame, as well as the non-woven fabrics, film materials and bonding materials required for each layer; S2. Gradient core preparation: Mix short fibers and superabsorbent resin evenly in a high-speed mixer according to a specific ratio, spread them on a special mold by an automatic feeding device. When spreading, turn on the low-frequency vibration device to form a prototype of the fast absorption layer. With the help of a high-precision injection device, inject the polyurethane elastomer into the preset position of the mold, and keep the pressure to make the support body tightly fit with the upper layer. After mixing long fibers and superabsorbent resin in another mixer, spread them on the upper layer and the support body, and increase the vibration frequency to form a water-locking layer and promote fiber interweaving; S3. Diversion frame integration: Use an extrusion molding machine to extrude the hydrophilic polymer material into a surrounding diversion frame blank at a suitable temperature, and use a laser etching device to etch diagonal diversion channels according to the design. Coat hot melt glue on the edge of the absorption layer, and hot press and composite the formed frame to ensure that the frame is firmly connected to the absorption layer; S4. Three-dimensional composite: Through a positioning tooling, cover the film material of the support layer with pits on the bottom of the absorption layer, make the support body accurately aligned with the pits, use a dispensing device to apply glue, reserve a movable gap, cover the non-woven fabric diversion layer with diversion grooves on the upper layer of the absorption layer according to the preset direction, and make the fibers of the two fit together through a mechanical rolling device; S5. Edge strengthening: Use a special edge cleaning device to remove the excess materials at the edge of the sanitary napkin and shape it. Use an ultrasonic welding device to weld the materials of each layer at the edge according to appropriate parameters to form a sealed edge that is higher than the core; S6. Quality inspection and packaging: Combine manual visual inspection and machine vision inspection to check the appearance of the sanitary napkin and the composite situation of each layer, measure the size with a high-precision instrument, simulate the use scenario to detect the absorption and anti-side leakage performance. Qualified products are packaged by an automatic packaging device using ethylene oxide sterilization and vacuum packaging technology, and are marked and boxed and then ready to be stored or sold.

[0012] The present invention has the following beneficial effects: 1. By setting the upper short fibers and the superabsorbent resin to be mixed in a specific ratio, it can quickly respond to the sudden outflow of menstrual blood, avoid discomfort or leakage risks caused by liquid retention. At the same time, the lower long fibers are intertwined with the superabsorbent resin to form a stable structure. Even after experiencing movement and bumps, it can maintain a dry surface and reduce skin problems caused by dampness.

[0013] 2. By setting the surrounding diversion frame at the edge of the absorption layer to be made of hydrophilic polymer material, and the internal diagonal diversion channel forms an angle of 30° - 60° with the longitudinal direction of the sanitary napkin, it can closely fit the body during movement, effectively intercept and divert the edge liquid, making the user more at ease.

[0014] 3. By setting the columnar support bodies made of polyurethane elastomer to be evenly distributed between the upper and lower layers of the absorption layer, vertically penetrating and tightly fitting, it ensures that the sanitary napkin can still maintain its shape after absorbing a large amount of liquid, and continuously plays the functions of absorption and anti-side leakage. Brief Description of the Drawings

[0015] Figure 1 It is a schematic diagram of the overall internal structure of a sanitary napkin with a non-deformable core during movement proposed by the present invention.

[0016] In the figure: 1. Bottom film layer; 2. Support layer; 3. Absorption layer; 4. Diversion layer; 5. Skin-friendly layer. Specific Embodiments

[0017] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments.

[0018] Refer to Figure 1 , a sanitary napkin with a non-deformable core during movement, which successively includes a bottom film layer 1, a support layer 2, an absorption layer 3, a diversion layer 4, and a skin-friendly layer 5 from bottom to top; The edge of the bottom film layer 1 and the absorption layer 3 form a sealed edge. The bottom film layer 1 is composed of a water-repellent non-woven fabric and a PE breathable film. Its water-repellent non-woven fabric has a high-grade water-repellent performance, which can effectively prevent liquid from leaking outwards, ensure a dry and clean external environment. The sealed edge not only enhances the stability of the overall structure, prevents the contents of the absorption layer 3 from being exposed, but also can closely fit the body during movement, reduce edge friction, and further strengthen the waterproof effect, eliminating the hidden danger of side leakage.

[0019] The surface of the support layer 2 is provided with pits adapted to the bottom of the absorption layer 3. The support layer 2 and the bottom film layer 1 are connected by grid glue, and the support layer 2 and the absorption layer 3 are locked by glue points around the support body. The support layer 2 is made of a polyester elastic film material, which endows the support layer 2 with good elasticity and toughness, enabling it to adapt to various dynamic changes of the body during movement. The pits designed on the surface, whether distributed in a regular hexagon, square or rhombus array, have their depth, diameter and spacing precisely considered and are perfectly adapted to the bottom of the absorption layer 3. The existence of the pits provides a precise positioning space for the bottom of the columnar support body on the one hand, and on the other hand, when the absorption layer 3 is stressed, the pits can buffer the pressure and disperse the stress points to ensure the structural stability of the absorption layer 3.

[0020] The absorption layer 3 is arranged as a double-layer gradient core. The upper layer of the absorption layer 3 is a fast absorption layer 3 of short fibers mixed with superabsorbent resin, and the lower layer of the absorption layer 3 is a water-locking layer of long fibers interwoven with superabsorbent resin. The edge of the absorption layer 3 is provided with a surrounding diversion frame higher than the surface of the core. The surrounding diversion frame is provided with an inclined diversion channel. The direction of the inclined diversion channel of the surrounding diversion frame forms an angle of 30° - 60° with the longitudinal direction of the sanitary napkin, which can fit the human body curve to the greatest extent during movement and effectively intercept the edge liquid. When the liquid flows to the edge, the inclined diversion channel quickly guides the liquid to the center of the absorption layer 3 to avoid liquid overflow and greatly reduce the risk of side leakage.

[0021] Columnar support bodies are evenly distributed between the upper layer and the lower layer of the absorption layer 3. The columnar support bodies vertically penetrate the upper and lower layers of the absorption layer 3. The columnar support bodies are made of polyurethane elastomer, with appropriate hardness and elasticity. After the absorption layer 3 absorbs a large amount of liquid, it prevents the upper and lower layers from being overly squeezed and causing structural collapse, keeps the pores inside the absorption layer 3 unblocked, and maintains good liquid transmission and storage capabilities; The top of the columnar support body is embedded in the bottom surface of the diversion layer 4, and there is a movable gap between the bottom of the diversion layer 4 and the pit of the support layer 2. The groove depth of the diversion layer 4 decreases from the edge to the center and forms a diversion slope with a higher edge and a lower center with the surrounding diversion frame; The surface of the diversion layer 4 is provided with non-woven fabric with diversion grooves. The groove depth of the non-woven fabric decreases from the edge to the center and forms a diversion slope with a higher edge and a lower center with the surrounding diversion frame. When menstrual blood contacts the diversion layer 4, it is first intercepted by the higher grooves at the edge, and then under the action of the slope, it quickly converges to the center and is then efficiently absorbed by the absorption layer 3. The bottom surface of the diversion layer 4 is fiber-embedded with the upper layer of the absorption layer 3, and the skin-friendly layer 5 is connected to the diversion layer 4 through spaced glue points.

[0022] A preparation method of a sports non-deformable core sanitary napkin includes the following steps: S1. Raw material preparation: Prepare superabsorbent resins with different properties. For the upper layer, select those with smaller particle sizes and moderate liquid absorption ratios; for the lower layer, use those with even smaller particle sizes and higher liquid absorption ratios. Combine hydrophilic fibers of different lengths, store them in proportion, and prepare polyurethane elastomer as the columnar support, hydrophilic polymer materials for the surrounding diversion frame, as well as non-woven fabrics, membrane materials, and bonding materials required for each layer. S2. Preparation of the gradient core: Mix short fibers and superabsorbent resins in a high-speed mixer according to a specific ratio, and spread them evenly on a special mold through an automatic feeding device. When spreading, turn on the low-frequency vibration device to form the prototype of the rapid absorption layer 3. With the help of a high-precision injection device, inject the polyurethane elastomer into the preset position of the mold, and keep the pressure to make the support tightly fit with the upper layer. After mixing long fibers and superabsorbent resins in another mixer, spread them on the upper layer and the support, and increase the vibration frequency to form the water-locking layer and promote fiber interweaving. S3. Integration of the diversion frame: Use an extrusion molding machine to extrude the hydrophilic polymer material into a surrounding diversion frame blank at a suitable temperature, and use a laser etching device to etch the inclined diversion channels according to the design. Coat hot melt adhesive on the edge of the absorption layer 3, and thermally press and compound the formed frame to ensure a firm connection between the frame and the absorption layer 3. S4. Three-dimensional compounding: Through a positioning tooling, cover the membrane material of the support layer 2 with pits on the bottom of the absorption layer 3, make the support accurately aligned with the pits, use a dispensing device to apply glue, leave a movable gap, cover the non-woven fabric diversion layer 4 with diversion grooves on the upper layer of the absorption layer 3 in the preset direction, and make the fibers of the two fit together through a mechanical rolling device. S5. Edge strengthening: Use a special edge cleaning device to remove the excess materials at the edge of the sanitary napkin and shape it. Use an ultrasonic welding device to weld the materials of each layer at the edge according to appropriate parameters to form a sealed edge that is higher than the core. S6. Quality inspection and packaging: Combine manual visual inspection and machine vision inspection to check the appearance of the sanitary napkin and the compounding situation of each layer, measure the size with a high-precision instrument, simulate the use scenario to detect the absorption and side leakage prevention performance. The qualified products are packaged by an automated packaging device using ethylene oxide sterilization and vacuum packaging technology, and are labeled and boxed before being prepared for storage or sale. Example 1:

[0023] Step 1: Raw material preparation: The bottom film layer is a water-repellent non-woven fabric composite PE breathable film with a thickness of 0.12 mm. The water-repellent non-woven fabric has a water-repellent grade of 5, and the PE breathable film has a breathable rate of 2200 mm / s. The edge is ultrasonically welded to the absorption layer to form a sealed edge with a width of 3.5 mm. The support layer is made of thermoplastic polyurethane elastomer with a thickness of 0.35 mm. The depth of the surface pits is 0.65 mm, the diameter is 1.2 mm, the pits are arranged in a square array, and the spacing is 2.5 mm, which is adapted to the bottom of the absorption layer. The upper layer of the absorption layer uses short fibers, which are cotton fibers with a length of 2 mm, and are mixed with a superabsorbent resin with a particle size of 100 μm and a liquid absorption ratio of 400 times at a mass ratio of 6:4, with a thickness of 2 mm. The lower layer is a water-locking layer. The long fibers are nylon fibers with a length of 5.5 mm, and are mixed with a superabsorbent resin with a particle size of 65 μm and a liquid absorption ratio of 510 times at a mass ratio of 7:3, with a thickness of 3.2 mm. The columnar support is made of a polyurethane elastomer with a Shore hardness of A58, with a diameter of 0.7 mm and a height of 2.8 mm. There are 70 distributed per 10 cm², vertically penetrating the upper and lower layers of the absorption layer; The diversion layer uses a non-woven fabric with diversion grooves on the surface. The groove depth is 0.13 mm, the density is 10 strips / cm, and the bottom surface is embedded with the fibers of the upper layer of the absorption layer through a needling process; The skin-friendly layer is a breathable skin-friendly fabric with a thickness of 0.22 mm, and is connected to the diversion layer through oval spacer adhesive dots with a diameter of 2.5 mm, and the adhesive dot spacing is 20 mm; Surrounding diversion frame: The hydrophilic polyester material has a width of 4.5 mm, the internal oblique diversion channel has a diameter of 0.18 mm, the density is 110 per cm, the direction of the oblique diversion channel is at an angle of 50° to the longitudinal direction of the sanitary napkin, and it is 0.7 mm higher than the surface of the core body.

[0024] Step 2: Preparation of the gradient core body. Short fibers and superabsorbent resin are stirred in a high-speed mixer at a rotation speed of 1050 r / min for 13 minutes, and then spread on a special mold by an automatic feeding device. When spreading, a low-frequency vibration device with a vibration frequency of 7 Hz is turned on, and continuous spreading for 13 minutes forms a prototype of the fast absorption layer. With the help of a high-precision injection device, the polyurethane elastomer is injected into the preset position of the mold at an injection pressure of 1.3 MPa and a temperature of 68 °C, and the pressure is maintained for 7 minutes to make the support tightly fit with the upper layer. After the long fibers and superabsorbent resin are stirred in another mixer at a rotation speed of 850 r / min for 16 minutes, they are spread on the upper layer and the support, and the vibration frequency is increased to 9.5 Hz, and spreading for 16 minutes forms the water-locking layer and promotes fiber interweaving.

[0025] Step 3: Integration of the diversion frame. Using an extrusion molding machine, the hydrophilic polyester material is extruded into a surrounding diversion frame blank at a temperature of 165 °C and an extrusion speed of 4.5 mm / s. The oblique diversion channels are etched according to the design by a laser etching device. Hot melt adhesive with a weight of 13 g / m² is coated on the edge of the absorption layer, and the formed frame is hot-pressed at a temperature of 118 °C and a pressure of 0.28 MPa for 4.5 minutes to ensure that the frame is firmly connected to the absorption layer.

[0026] Step 4: Three-dimensional composite. Through the positioning tooling, cover the support layer film with pits on the bottom of the absorption layer, so that the bottom of the support body is accurately aligned with the pits of the support layer. Use a dispensing device to apply glue. After the glue cures, a 0.25-mm movable gap is reserved between the bottom of the support body and the pits. Cover the non-woven fabric diversion layer with diversion grooves on the upper layer of the absorption layer in the preset direction. Use a mechanical rolling device to make the fibers of the two fit together at a rolling speed of 1.8 m / min.

[0027] Step 5: Edge strengthening. Use a vacuum adsorption cleaning device to remove the excess materials at the edges of the sanitary napkin and shape it. Use an ultrasonic welding device to weld the materials of each layer at the edge with a welding power of 450 W and a welding time of 0.8 s for each weld point, forming a sealed edge that is 0.7 mm higher than the core body.

[0028] Step 6: Quality inspection and packaging. Combine manual visual inspection and machine vision inspection to check the appearance of the sanitary napkin and the composite situation of each layer. Use a high-precision measuring instrument to measure the dimensions. Simulate the use scenario to detect the absorption and anti-side leakage performance. The qualified products are packaged by an automated packaging device using ethylene oxide sterilization and vacuum packaging technologies, and are marked and boxed and then ready for warehousing or sales. Example 2:

[0029] Step 1: Raw material preparation. The bottom film layer is made of water-repellent non-woven fabric with a thickness of 0.1 mm laminated with a PE breathable film. The water-repellent grade of the water-repellent non-woven fabric reaches level 4, and the air permeability of the PE breathable film is 2000 mm / s. The edge of the bottom film layer and the absorption layer form a sealed edge with a width of 3 mm through a hot pressing process. The support layer is made of a polyester elastomer material with a thickness of 0.3 mm, the depth of the surface pits is 0.6 mm, the diameter is 1 mm, the pits are distributed in a regular hexagonal array, and the spacing is 2 mm, which is adapted to the bottom of the absorption layer. The upper layer of the absorption layer uses viscose fibers with a short fiber length of 2.5 mm, which are mixed with a superabsorbent resin with a particle size of 110 μm and a liquid absorption ratio of 420 times at a mass ratio of 6:4, and the thickness is 2.2 mm. In the lower layer of the absorption layer, the long fibers in the water-locking layer use polyester fibers with a length of 6 mm, which are mixed with a superabsorbent resin with a particle size of 70 μm and a liquid absorption ratio of 520 times at a mass ratio of 7:3, and the thickness is 3.3 mm. The columnar support body is made of a polyurethane elastomer with a Shore hardness of A55, with a diameter of 0.6 mm and a height of 2.5 mm, and is evenly distributed in the absorption layer at a density of 60 per 10 cm², vertically penetrating the upper and lower layers of the absorption layer. The diversion layer uses non-woven fabric with diversion grooves on the surface. The depth of the grooves is 0.12 mm, the density is 9 grooves / cm, and the bottom surface is fitted with the fibers of the upper layer of the absorption layer through mechanical rolling. The skin-friendly layer is made of a breathable hydrophilic fabric with a thickness of 0.2 mm and is connected to the diversion layer through circular spacer adhesive dots with a diameter of 2 mm. The spacing between the adhesive dots is 18 mm. The wrap-around diversion frame is made of hydrophilic polypropylene material, with a width of 4 mm. The diameter of the internal diagonal diversion channels is 0.15 mm, and the density is 100 per cm. The direction of the diagonal diversion channels forms a 45° angle with the longitudinal direction of the sanitary napkin and is 0.6 mm higher than the surface of the core body.

[0030] Step 2: Preparation of the gradient core body. Short fibers and superabsorbent resin are stirred in a high-speed mixer at a speed of 1100 r / min for 12 minutes, and then spread on a special mold by an automatic feeding device. When feeding, a low-frequency vibration device with a vibration frequency of 6 Hz is turned on, and continuous feeding for 12 minutes forms a prototype of the rapid absorption layer. With the aid of a high-precision injection device, polyurethane elastomer is injected into the preset position of the mold at an injection pressure of 1.2 MPa and a temperature of 65 °C, and the pressure is maintained for 6 minutes to make the support body fit tightly with the upper layer. After long fibers and superabsorbent resin are stirred in another mixer at a speed of 900 r / min for 15 minutes, they are spread on the upper layer and the support body, and the vibration frequency is increased to 9 Hz, and feeding for 15 minutes forms a water-locking layer and promotes fiber interweaving.

[0031] Step 3: Integration of the diversion frame. Using an extrusion molding machine, hydrophilic polypropylene material is extruded into a wrap-around diversion frame blank at a temperature of 160 °C and an extrusion speed of 4 mm / s. The diagonal diversion channels are etched according to the design by a laser etching device, and a hot melt adhesive of 12 g / m² is coated on the edge of the absorption layer. The formed frame is hot-pressed at a temperature of 115 °C and a pressure of 0.25 MPa for 4 minutes to ensure a firm connection between the frame and the absorption layer.

[0032] Step 4: Three-dimensional composite. Through a positioning tooling, the support layer film material with pits is covered on the bottom of the absorption layer, so that the bottom of the support body is accurately aligned with the pits of the support layer. Glue is dot-coated with a dispensing device, and after the glue is cured, a 0.2-mm movable gap is reserved between the bottom of the support body and the pits. The non-woven fabric diversion layer with diversion grooves is covered on the upper layer of the absorption layer according to the preset direction, and the fibers of the two are made to interlock by a mechanical rolling device at a rolling speed of 1.5 m / min.

[0033] Step 5: Edge strengthening. Use a brush roller cleaning device to remove the excess material at the edge of the sanitary napkin and shape it. Use an ultrasonic welding device to weld the materials of each layer at the edge with a welding power of 400 W and a welding time of 0.7 seconds for each weld point to form a sealed edge that is 0.6 mm higher than the core body.

[0034] Step 6: Quality inspection and packaging. Combine manual visual inspection and machine vision inspection to check the appearance of the sanitary napkin and the composite situation of each layer. Measure the size with a high-precision measuring instrument, and simulate the use scenario to detect the absorption and anti-side leakage performance. Qualified products are packaged by an automated packaging equipment using ethylene oxide sterilization and vacuum packaging technology, and are ready for warehousing or sales after being labeled and boxed. Example 3:

[0035] Step 1: Raw material preparation. The bottom film layer is a water-repellent non-woven fabric with a thickness of 0.08 mm laminated with a PE breathable film. The water-repellent non-woven fabric has a water-repellent grade of 3, and the PE breathable film has a gas permeability of 1800 mm / s. The edge is pasted to the absorption layer with hot melt adhesive to form a sealed edge with a width of 2.5 mm. The support layer is made of styrene-butadiene-styrene block copolymer elastomer with a thickness of 0.25 mm. The surface pit depth is 0.5 mm, the diameter is 0.8 mm, the pits are arranged in a diamond array with a spacing of 1.8 mm, and it fits the bottom of the absorption layer. The upper short fibers of the absorption layer are modal fibers with a length of 3 mm, mixed with a superabsorbent resin with a particle size of 120 μm and a liquid absorption ratio of 430 times at a mass ratio of 6:4, and the thickness is 2.4 mm. The lower water-locking layer, the long fibers are acrylic fibers with a length of 6.5 mm, mixed with a superabsorbent resin with a particle size of 75 μm and a liquid absorption ratio of 530 times at a mass ratio of 7:3, and the thickness is 3.5 mm. The columnar support is made of polyurethane elastomer with a Shore hardness of A52, with a diameter of 0.5 mm and a height of 2.3 mm, and 55 are distributed per 10 cm², vertically penetrating the upper and lower layers of the absorption layer; The surface of the diversion layer is a non-woven fabric with diversion grooves, the groove depth is 0.11 mm, the density is 8 grooves / cm, and the bottom surface is embedded with the upper layer fibers of the absorption layer through a chemical bonding process; The skin-friendly layer is a breathable skin-friendly fabric with a thickness of 0.18 mm, and is connected to the diversion layer through triangular spacer glue dots with a diameter of 1.8 mm, and the glue dot spacing is 16 mm; The surrounding diversion frame is made of hydrophilic polyamide material, with a width of 3.5 mm, the internal oblique diversion channel has a diameter of 0.13 mm, the density is 90 per cm, the direction of the oblique diversion channel is at an angle of 35° to the longitudinal direction of the sanitary napkin, and it is 0.5 mm higher than the surface of the core body.

[0036] Step 2: Preparation of the gradient core body: The short fibers and the superabsorbent resin are stirred in a high-speed mixer at a rotation speed of 1150 r / min for 11 minutes, and then spread on a special mold by an automatic feeding device. During the feeding process, a low-frequency vibration device with a vibration frequency of 5 Hz is turned on, and the feeding continues for 11 minutes to form a prototype of the rapid absorption layer. With the help of a high-precision injection device, the polyurethane elastomer is injected into the preset position of the mold at an injection pressure of 1.1 MPa and a temperature of 62 °C, and the pressure is maintained for 5 minutes to make the support body fit tightly with the upper layer. After the long fibers and the superabsorbent resin are stirred in another mixer at a rotation speed of 950 r / min for 14 minutes, they are spread on the upper layer and the support body, and the vibration frequency is increased to 8.5 Hz, and the feeding is carried out for 14 minutes to form a water-locking layer and promote fiber interweaving.

[0037] Step 3: Integration of the diversion frame: Using an extrusion molding machine, the hydrophilic polyamide material is extruded into a ring-shaped diversion frame blank at a temperature of 155 °C and an extrusion speed of 3.5 mm / s. The laser etching equipment is used to etch the oblique diversion channels according to the design. A hot melt adhesive of 11 g / m² is coated on the edge of the absorption layer, and the formed frame is hot-pressed at a temperature of 112 °C and a pressure of 0.22 MPa for 3.5 minutes to ensure a firm connection between the frame and the absorption layer.

[0038] Step 4: Three-dimensional composite: Through the positioning tooling, the support layer film material with pits is covered on the bottom of the absorption layer, so that the bottom of the support body is accurately aligned with the pits of the support layer. The glue is dot-coated with a dispensing device, and after the glue is cured, a movable gap of 0.15 mm is reserved between the bottom of the support body and the pits. The non-woven fabric diversion layer with diversion grooves is covered on the upper layer of the absorption layer according to the preset direction, and the mechanical rolling device is used to make the fibers of the two fit together at a rolling speed of 1.2 m / min.

[0039] Step 5: Edge strengthening: Use a brush roller cleaning device to remove the excess materials at the edge of the sanitary napkin and shape it. Use an ultrasonic welding device to weld the materials of each layer at the edge with a welding power of 350 W and a welding time of 0.6 seconds for each weld point to form a sealed edge that is 0.5 mm higher than the core body.

[0040] Step 6: Quality inspection and packaging: Combine manual visual inspection and machine vision inspection to check the appearance of the sanitary napkin and the composite situation of each layer. Use a high-precision measuring instrument to measure the size, and simulate the use scenario to detect the absorption and anti-side leakage performance. The qualified products are packaged by an automatic packaging device using ethylene oxide sterilization and vacuum packaging technology, and are labeled and boxed and then ready for storage or sale.

[0041] It should be noted that to comprehensively verify the performance advantages of the sports-invariant core sanitary napkin compared to traditional sanitary napkins in different sports scenarios, 15 female volunteers were recruited respectively to conduct tests on three common sports: rope skipping, yoga, and running. The test objects were the sports-invariant core sanitary napkins prepared in Example 1, Example 2, and Example 3, as well as Comparative Example 1 and Comparative Example 2. Comparative Example 1 used a traditional non-woven sanitary napkin, and Comparative Example 2 used a relatively soft non-woven fabric. They were tested uniformly; In the 10-minute rope skipping test, the total absorption of the volunteers using the sanitary napkin of Example 1 was approximately 1080 grams within 10 minutes. Most volunteers reported that the absorption effect was always good. The total absorption of the volunteers using the sanitary napkin of Example 2 was approximately 1000 grams in 10 minutes. Although the absorption speed was slightly lower than that of Example 1, it could still efficiently handle the menstrual blood flow and maintain a dry surface state. The total absorption of the volunteers using the sanitary napkin of Example 3 was approximately 1020 grams in 10 minutes, which could quickly absorb a large amount of menstrual blood. The total absorption of the volunteers using Comparative Example 1 was approximately 480 grams within 10 minutes. As the rope skipping time increased, the absorption speed gradually couldn't keep up with the outflow speed, and obvious liquid accumulation appeared on the surface. The total absorption of the volunteers using Comparative Example 2 was approximately 720 grams in 10 minutes, and the shortcoming of the absorption performance gradually emerged during the rope skipping process, as shown in Table 1 specifically: Table 1: Comparison table of absorption, anti-side leakage, and air permeability of 15 volunteers after rope skipping test Serial number Absorption amount in 10 minutes (g) Side leakage prevention ability (%) Air permeability (%) Example 1 1080g 80% 60% Example 2 1000g 60% 40% Example 3 1020g 750% 50% Comparative example 1 480g 20% 20% Comparative example 2 720g 40% 40% It should be noted that the anti-side leakage ability of Example 1 was 80%, significantly higher than 20% of Comparative Example 1 and 40% of Comparative Example 2, and also better than 60% of Example 2. A higher anti-side leakage ability means that during rope skipping, menstrual blood is less likely to leak from the edge of the sanitary napkin, which can provide more reliable protection for women, avoid the embarrassment caused by side leakage, and make women feel more at ease during exercise.

[0042] The air permeability of Example 1 was 60%, significantly higher than 20% of Comparative Example 1, and also better than 40% of Comparative Example 2 and Example 2. Good air permeability allows air to circulate better between the sanitary napkin and the skin. During rope skipping, women sweat more. Good air permeability can effectively reduce the sense of stuffiness and dampness, keep the private part dry and comfortable, reduce the risk of skin discomfort and infection caused by a humid environment, and improve the exercise experience during menstruation.

[0043] It should be noted that in the 1-hour yoga class test, the absorption rate of the sanitary napkin of Example 1 reached 97%. The double-layer gradient absorption layer can quickly absorb menstrual blood in various postures. The lower water-locking layer effectively prevents liquid backflow, ensuring a stable absorption effect. The absorption rate of the sanitary napkin of Example 2 is about 95%. The absorption layer structure is stable, can adapt to the changes in yoga postures, quickly absorb menstrual blood and maintain good water-locking performance, providing a continuous dry experience for users. The absorption rate of the sanitary napkin of Example 3 reached 93%. In different yoga postures, it can efficiently absorb menstrual blood and maintain a high absorption rate. Due to posture changes, the absorption of menstrual blood by the sanitary napkin of Comparative Example 1 is uneven, resulting in an overall absorption rate of about 85%. The absorption rate of the sanitary napkin of Comparative Example 2 is 90% in some special postures, as shown in Table 2 specifically: Table 2: Comparison table of absorption rate, backflow volume and comfort for 15 volunteers after 1 hour of yoga practice Serial number Absorption rate (%) Back leakage amount (g) Comfort level (%) Example 1 97% 3.5g 60% Example 2 95% 3.8g 50% Example 3 93% 3.5g 55% Comparative example 1 85% 7.2g 20% Comparative example 2 90% 8.5g 40% It should be noted that the absorption rate of Example 1 reached 97%, higher than 95% of Example 2, 93% of Example 3, far exceeding 85% of Comparative Example 1, and also higher than 90% of Comparative Example 2. This shows that Example 1 can absorb menstrual blood more efficiently. Under the same test conditions, it can absorb and lock more menstrual blood in the sanitary napkin, effectively reducing the leakage risk caused by insufficient absorption, providing a more reliable absorption guarantee for users. Especially when the menstrual flow is large during menstruation, the advantage is more obvious; In terms of the backflow volume, that of Example 1 is 3.5 g, lower than 3.8 g of Example 2, the same as that of Example 3, and much lower than 7.2 g of Comparative Example 1 and 8.5 g of Comparative Example 2. A lower backflow volume means that after the menstrual blood is absorbed, less will seep out to the surface of the sanitary napkin again, always keeping the surface dry, avoiding the dampness and discomfort caused by backflow, greatly improving the comfort and hygiene during use, reducing the long-term contact between the skin and menstrual blood, and lowering the infection risk; The comfort level of Example 1 is 60%, higher than 50% of Example 2, 55% of Example 3, significantly higher than 20% of Comparative Example 1, and also higher than 40% of Comparative Example 2. The comfort level comprehensively reflects various factors such as the material, fit, and air permeability of the sanitary napkin. A higher comfort level indicates that Example 1 performs well in these aspects, bringing a better experience for users during use. Whether in daily activities or during exercise, it can make users feel more comfortable and reduce the discomfort caused by improper use of the sanitary napkin.

[0044] During the 30-minute running test, the average absorption per minute of the volunteers using the sanitary napkin of Example 1 reached 12 grams within 30 minutes. The absorption layer can quickly absorb menstrual blood, keep the surface dry, and has a stable absorption speed, effectively coping with the continuous outflow of menstrual blood during running. The average absorption per minute of the volunteers using the sanitary napkin of Example 2 reached 10 grams within 30 minutes. Although the absorption amount was slightly lower than that of Example 1, it could meet the menstrual blood absorption needs during running. The average absorption per minute of the volunteers using the sanitary napkin of Example 3 reached 9.5 grams within 30 minutes, and it could also quickly absorb menstrual blood and keep the surface dry during running. The average absorption per minute of the volunteers using the sanitary napkin of Comparative Example 1 reached 6 grams within 30 minutes, and the absorption speed could not keep up with the outflow speed of menstrual blood, and the surface had an obvious sense of dampness. The average absorption per minute of the volunteers using the sanitary napkin of Comparative Example 2 reached 8 grams within 30 minutes, and its absorption effect was not good, as shown in Table 3 specifically: Table 3: Comparison table of absorption amount, flexibility and antibacterial performance of 15 volunteers during 30-minute running Serial number Absorption amount (g / min) Flexibility (%) Antibacterial property (%) Example 1 12 g / min 75% 80% Example 2 10 g / min 70% 70% Example 3 9.5 g / min 73% 75% Comparative example 1 6 g / min 50% 50% Comparative example 2 8 g / min 60% 60% It should be noted that in terms of flexibility, Example 1 was 75%, higher than 70% of Example 2, 73% of Example 3, and also far ahead of 50% of Comparative Example 1 and 60% of Comparative Example 2. Sanitary napkins with good flexibility can better fit the body curve during use. Whether in daily activities or sports, they can reduce the discomfort caused by the non-fitting of sanitary napkins, improve the comfort of users, and at the same time reduce the possibility that the absorption and side leakage prevention performance of sanitary napkins are affected due to bending and twisting; The antibacterial performance of Example 1 was 80%, higher than 70% of Example 2, 75% of Example 3, and 50% of Comparative Example 1 and 60% of Comparative Example 2. Higher antibacterial performance can effectively inhibit the growth of bacteria, reduce the odor and infection risks caused by bacterial reproduction, provide a healthier sanitary guarantee for women during this special period of menstruation, and help maintain the cleanliness and healthy environment of the private parts.

[0045] Generally speaking, the sanitary napkin of Example 1 in the present invention shows significant advantages in many aspects. In terms of absorption, whether in daily life or during exercise, it can quickly and efficiently absorb menstrual blood, reduce leakage and the frequency of replacement, and has excellent side leakage prevention ability. It can firmly lock blood during exercises such as yoga, running, and skipping rope. It has good flexibility, fits the body curve, has good air permeability, is comfortable to use, and its antibacterial performance is even more prominent. It can inhibit bacteria, create a safe environment for the private parts, and comprehensively care for women during menstruation, bringing a better quality, healthy and comfortable use experience to users.

[0046] The above are only the preferred specific embodiments 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 should cover within the protection scope of the present invention any equivalent replacement or change made according to the technical solution of the present invention and its inventive concept.

Claims

1. A sports-invariant core sanitary napkin, characterized in that, It successively includes a bottom film layer (1), a support layer (2), an absorption layer (3), a diversion layer (4) and a skin-friendly layer (5) from bottom to top; The edge of the bottom film layer (1) forms a sealed edge with the absorption layer (3). The surface of the support layer (2) is provided with pits adapted to the bottom of the absorption layer (3). The absorption layer (3) is arranged as a double-layer gradient core. The upper layer of the absorption layer (3) is a quick absorption layer (3) of short fibers mixed with superabsorbent resin, and the lower layer of the absorption layer (3) is a water-locking layer of long fibers interwoven with superabsorbent resin. Columnar supports are evenly distributed between the upper layer and the lower layer of the absorption layer (3). The columnar supports vertically penetrate the upper and lower layers of the absorption layer (3). The surface of the diversion layer (4) is a non-woven fabric provided with diversion grooves. The bottom surface of the diversion layer (4) is fiber-embedded with the upper layer of the absorption layer (3). The skin-friendly layer (5) is connected to the diversion layer (4) through spaced adhesive dots.

2. The motion-invariant core sanitary napkin according to claim 1, wherein The edge of the absorption layer (3) is provided with a surrounding diversion frame higher than the surface of the core. The surrounding diversion frame is provided with an inclined diversion channel. The direction of the inclined diversion channel of the surrounding diversion frame forms an angle of 30°-60° with the longitudinal direction of the sanitary napkin.

3. The motion-invariant core body sanitary napkin according to claim 1, wherein, The top of the columnar support is embedded in the bottom surface of the diversion layer (4), and a movable gap is reserved between the bottom of the diversion layer (4) and the pit of the support layer (2).

4. The motion-immutable core body sanitary napkin according to claim 3, characterized in that, The support layer (2) and the bottom film layer (1) are connected by grid glue, and the support layer (2) and the absorption layer (3) are locked by the peripheral adhesive dots of the columnar support.

5. The motion-invariant core sanitary napkin according to claim 2, characterized in that, The groove depth of the diversion layer (4) decreases from the edge to the center and forms a diversion slope with a high edge and a low center with the surrounding diversion frame.

6. The preparation method of a sports-invariant core sanitary napkin according to any one of claims 1-5, characterized in that, It includes the following steps: S1. Raw material preparation: Prepare superabsorbent resins with different characteristics. Select those with small particle size and moderate liquid absorption ratio for the upper layer, and those with smaller particle size and higher liquid absorption ratio for the lower layer. Match hydrophilic fibers of different lengths, store them in proportion, and prepare polyurethane elastomer for columnar supports, hydrophilic polymer materials for surrounding diversion frames, as well as non-woven fabrics, film materials and bonding materials required for each layer; S2. Gradient core preparation: Mix short fibers and superabsorbent resin evenly in a high-speed mixer according to a specific ratio, and spread them on a special mold through an automatic feeding device. When spreading, turn on the low-frequency vibration device to form a prototype of the quick absorption layer (3). With the help of a high-precision injection device, inject polyurethane elastomer into the preset position of the mold, and keep the pressure to make the support tightly embedded with the upper layer. After mixing long fibers and superabsorbent resin in another mixer, spread them on the upper layer and the support, and increase the vibration frequency to form a water-locking layer and promote fiber interweaving; S3. Diversion frame integration: Use an extrusion molding machine to extrude hydrophilic polymer materials into a surrounding diversion frame blank at a suitable temperature, use a laser etching device to etch inclined diversion channels according to the design, coat hot melt adhesive on the edge of the absorption layer (3), and thermocompression bond the formed frame to ensure firm connection between the frame and the absorption layer (3); S4. Three-dimensional composite: Through the positioning tooling, cover the support layer (2) film material with pits on the bottom of the absorption layer (3), accurately align the support body with the pits, apply glue with a dispensing device, reserve an activity gap, cover the non-woven fabric diversion layer (4) with diversion grooves on the upper layer of the absorption layer (3) in the preset direction, and make the fibers of the two fit together through a mechanical rolling device; S5. Edge strengthening: Use a special edge cleaning device to remove the excess materials at the edge of the sanitary napkin and shape it. Use an ultrasonic welding device to weld the materials of each layer at the edge according to appropriate parameters to form a sealed edge that is higher than the core; S6. Quality inspection and packaging: Combine manual visual inspection and machine vision inspection to check the appearance of the sanitary napkin and the composite situation of each layer. Measure the size with a high-precision instrument, simulate the use scenario to detect the absorption and anti-side leakage performance. The qualified products are packaged by an automated packaging device using ethylene oxide sterilization and vacuum packaging technology, and are marked and boxed before being prepared for storage or sale.

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