Absorbing core body with velvet net interlayer structure

Abstract

The utility model relates to the technical field of absorption structures in absorption products, in particular to an absorption core with a pile net interlayer structure. The technical scheme is as follows: the liquid storage bag mainly comprises an upper layer, a lower layer, a middle layer and liquid storage particles, wherein the upper layer and the lower layer are formed by horizontal yarns; the middle layer is formed by vertical yarns interwoven or bonded with the horizontal yarns; the liquid storage particles are any one of a single natural fiber, a single artificial fiber, an artificial fiber compounded with SAP, and a natural fiber compounded with SAP. According to the scheme, the use of SAP (super absorbent polymer) is integrally reduced or selectively avoided, the integral structure is high in supporting performance, is not easy to obviously expand and deform after the core body absorbs water, is lower in reverse osmosis rate, has certain air permeability, and is a water-absorbing core body structure with a better structure.

Description

Technical Field

[0001] This utility model relates to the field of absorbent structure technology in absorbent products, specifically to an absorbent core with a velvet mesh sandwich structure. Background Technology

[0002] Absorbent materials are products that use woven or nonwoven layered structures to fix liquids or near-liquid substances to a volume equal to or exceeding their own volume. They are widely used in various situations requiring dryness or near-dryness, odorlessness or low odor, and minimal or no surface residue, and fall under the category of hygiene and cleaning products. Before the introduction of modern polymer technology, these effects were achieved using woven fabrics or natural, porous materials. However, these older methods had limitations, such as relatively high costs and less than ideal absorbency. Specifically, after being spun into yarn, the microstructure of ordinary woven fabrics lacks sufficient space for adsorbing substances, and the hydrophilic properties of natural fibers are not modified. Therefore, even cotton fibers, which have good absorbency, have an absorption ratio of less than 50. Furthermore, naturally occurring porous materials, such as fluffy wood chips or natural sponges, are usually quite heavy and cannot actually absorb much water, and their water-fixing effect is not particularly good.

[0003] SAP, a polymer material that emerged in the 20th century, typically has an absorbency ratio ranging from 400 to 700, with some specialty materials exhibiting even higher ratios, far exceeding the performance of cotton fibers. The advent of hydrophilic surface modifiers has endowed various fibers with a certain degree of water absorption. The resulting PE / PET / SAP absorbent composite core can absorb large amounts of liquid and provide excellent retention. Even under pressure or natural placement, the amount of liquid seeping out or re-seeping is significantly less compared to previous fabrics or natural materials, thus drastically changing the current state of hygiene products. In particular, for modern healthcare, this new absorbent material has clearly elevated the level of medical and hygiene conditions to unprecedented heights and is already being used in various industries and settings in modern life.

[0004] However, conventional absorber structures still have room for improvement. Specifically, while the high application rate of SAP has improved the absorption performance of absorbers, the simple nonwoven layer structure sandwiching SAP does not impose any structural constraints on the SAP. Therefore, before the liquid is completely absorbed by the SAP material, residual liquid on the surface can still seep back through the pores of the nonwoven layer structure, resulting in visible dampness on the outer surface of the absorber. Therefore, the improvement of new absorbers generally involves adding a polymer membrane layer with anti-backflow and unidirectional permeability, such as a PE membrane, between the nonwoven layer structure and the central SAP. This makes it more difficult for liquid to seep back under external pressure after passing through the surface nonwoven layer structure and the unidirectional polymer membrane layer, even if it is not absorbed by the SAP. This significantly improves the anti-backflow performance of the absorber and also improves its surface dryness.

[0005] From a further perspective, the high-ratio application of SAP (Solid Polymer Assay) does not solve the problem of significant liquid backflow. Even if the unidirectional flow of the polymer membrane can largely prevent liquid from seeping back into the surface nonwoven structure, the liquid will still flow between the SAP layers, uncontrollably moving to other areas of the absorbent or accumulating in place. This not only causes significant localized swelling of the absorbent along with the expanded SAP, resulting in an abnormal surface feel on human skin or other contact surfaces, especially the foreign body sensation caused by the expanded SAP. Furthermore, the unidirectional flow of the polymer membrane cannot completely block liquid backflow; a considerable amount of liquid will still be squeezed back to the nonwoven surface, making the absorbent surface damp. Moreover, the increased use of SAP to improve absorption capacity also causes environmental pollution due to its difficulty in natural degradation, increasing remediation costs.

[0006] In summary, while existing technologies may have made improvements to address the above issues, choosing a more suitable structural solution remains a real-world problem worthy of further research and practice. Utility Model Content

[0007] To address the technical deficiencies in the background art, this utility model proposes an absorbent core with a velvet mesh sandwich structure, which solves the aforementioned technical problems and meets practical needs. The specific technical solution is as follows:

[0008] An absorbent core with a velvet-textured sandwich structure includes a matrix with a three-dimensional structure, wherein the matrix is ​​composed of an upper layer, a middle layer and a lower layer from top to bottom, and the matrix also encapsulates liquid storage microparticles.

[0009] The upper and lower layers are both formed by weaving several horizontal yarns to create a planar structure. Each upper or lower layer has a first plane and a second plane opposite to the first plane. The first and second planes tend to be flush in their own planar directions, and there is an opening between at least any two horizontal yarns in the same plane that connects the first and second planes. Any two horizontal yarns intersect each other and form nodes at the intersections. The middle layer is composed of several vertical yarns that are parallel to the normal direction of the first or second plane, or tend to be perpendicular to the normal direction and have an acute angle of ≤45° between them. The vertical yarns intersect or are connected with the horizontal yarns or nodes to form a three-dimensional structure, and the openings have no vertical yarns or only a small number of vertical yarns, so that the openings of the vertical yarns in the upper and lower layers account for less than 0.5% of the total number of openings.

[0010] Between the upper and lower layers are several small, interconnected liquid storage cavities formed by vertical yarn division. The liquid storage microparticles are housed within the liquid storage cavities. The overall porosity of the matrix is ​​65-95%, and the volume of the liquid storage cavity accounts for no less than 90% of the overall porosity. The liquid storage microparticles are any one of natural fibers, synthetic fibers, synthetic fibers composited with SAP, or natural fibers composited with SAP.

[0011] As a further technical solution of this utility model, when the liquid storage microparticle is a single natural fiber or a single artificial fiber, the liquid storage microparticle is fused and bonded or wrapped with the vertical yarn, fused and bonded or wrapped with one or more adjacent liquid storage microparticles, or free in the space of the liquid storage cavity.

[0012] As a further technical solution of this utility model, when the liquid storage microparticle is a synthetic fiber composited with SAP or a natural fiber composited with SAP, the synthetic fiber segment or natural fiber segment of the liquid storage microparticle is fused and bonded to the vertical yarn or wrapped as a whole, fused and bonded to or wrapped with one or more adjacent liquid storage microparticles, or free in the space of the liquid storage cavity.

[0013] As a further technical solution of this utility model, when the liquid storage microparticles are natural fibers or artificial fibers, the length of a single liquid storage microparticle is 0.5-50mm.

[0014] As a further technical solution of this utility model, at least one of the openings in the upper or lower layer is formed by any two, three or four horizontal yarns interlacing and surrounding each other.

[0015] As a further extension of the above technical solution, the fineness of the horizontal yarn is 30-200D and the F number is 12-288.

[0016] As a further extension of the above technical solution, the average fineness of the vertical yarn is 10-200D and the F number is 1-144.

[0017] As a further extension of the above technical solution, the basis weight of the substrate is 80-400 gsm and the thickness is 0.5-3.0 mm.

[0018] The beneficial effects of this utility model are as follows:

[0019] The application of this absorbent core in SAP is reduced to a small amount or not needed. It basically achieves the permeability and flow of liquid through the original three-dimensional structure. After the liquid comes into contact with the surface of the absorbent core, it can quickly penetrate into it. When the liquid enters, due to the large number of tiny spaces between the various connection points in the three-dimensional structure, and the fact that any connection point in the three-dimensional structure is a composite line made of fine yarns, the number of capillary-like spaces is even more numerous. Under the clamping of the above-mentioned fine, velvety mesh-like micro-spaces, the molecular force between the liquid and the three-dimensional structure is more obvious. After the liquid penetrates into the absorbent core, it is not easy for it to seep back. Moreover, the absorbent core can still maintain a certain degree of air permeability after absorbing water.

[0020] Furthermore, the three-dimensional structure of the absorbent core is also incorporating water-absorbing fiber material, which further enhances the adsorption stability of liquid within the absorbent core. If a small amount of SAP is added, the liquid absorption performance can be further improved. Even if the SAP or water-absorbing fiber material absorbs water and swells, the absorbent core is unlikely to exhibit any visible changes in its surface shape due to the large tensile strength of its three-dimensional structure in the thickness direction.

[0021] In summary, this absorbent core significantly improves surface dryness and reduces the frequency of liquid backflow while reducing the application of SAP and maintaining good absorbency. It also has a certain degree of breathability, resulting in a less stuffy feeling compared to existing general-configuration absorbent cores. Overall, its environmental friendliness is also improved compared to existing general-configuration absorbent cores. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the cross-sectional structure of the absorber core described in this utility model.

[0023] Figure 2 This is a three-dimensional structural diagram of the absorbent core described in this utility model.

[0024] Figure 3 This is a schematic diagram illustrating the microscopic composite effect of the vertical yarn and liquid storage microparticles described in this utility model.

[0025] Figure 4This is a schematic diagram illustrating the weaving effect of the upper or lower layer described in this utility model. Figure 1 .

[0026] Figure 5 This is a schematic diagram illustrating the weaving effect of the upper or lower layer described in this utility model. Figure 2 .

[0027] Figure 6 This is a schematic diagram illustrating the weaving effect of the upper or lower layer described in this utility model. Figure 3 .

[0028] Among them: upper layer 1, lower layer 2, middle layer 3, liquid storage particles 4, horizontal yarn 5, first plane 6, second plane 7, opening 8, node 9, vertical yarn 10, liquid storage cavity 11. Detailed Implementation

[0029] The embodiments of this utility model will be described below with reference to the accompanying drawings and related examples. The embodiments of this utility model are not limited to the following examples, and this utility model 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.

[0030] Combination Figures 1 to 6 As shown, an absorbent core with a velvet sandwich structure includes a matrix with a three-dimensional structure, which is composed of an upper layer 1, a middle layer 3 and a lower layer 2 from top to bottom, and the matrix also encapsulates liquid storage microparticles 4.

[0031] The upper layer 1 and the lower layer 2 are both formed by weaving several horizontal yarns 5 to form a planar structure. Each upper or lower layer has a first plane 6 and a second plane 7 opposite to the first plane 6. The first plane 6 and the second plane 9 tend to be flush in their own planar directions, and there is an opening 8 between at least any two horizontal yarns 5 in the same plane that runs through the first plane 6 and the second plane 7. Any two horizontal yarns 5 intersect each other and form a node 9 at the intersection. The middle layer 3 is composed of several vertical yarns 10 that are parallel to the normal direction n of the first plane 6 or the second plane 7, or tend to the normal direction n and have an acute angle of ≤45° between them. The vertical yarns 10 intersect or are connected with the horizontal yarns 5 or the nodes 9 to form a three-dimensional structure, so that there are no vertical yarns 10 or only a small number of vertical yarns 10 at the openings 8, and the number of openings 8 of vertical yarns 10 in the upper layer 1 and the lower layer 2 accounts for less than 0.5% of the total number of openings 8.

[0032] Between the upper layer 1 and the lower layer 2, there are several small and interconnected liquid storage cavities 11 formed by vertical yarns 10. The liquid storage particles 4 are housed within the liquid storage cavities 11. The overall porosity of the matrix is ​​65-95%, and the volume of the liquid storage cavity 4 accounts for no less than 90% of the overall porosity. The liquid storage particles 4 are any one of natural fibers, artificial fibers, artificial fibers composited with SAP, and natural fibers composited with SAP.

[0033] The application of this absorbent core to SAP has been changed from extensive use to limited use or no use at all, reducing dependence on SAP from the source. In order to achieve its due water absorption performance, it has been transformed to realize the original function of a single SAP by liquid storage particles 4 wrapped in the liquid storage space divided by vertical yarns—the liquid storage cavity 11. In other words, the technical solution of this utility model basically realizes the passability and flow of liquid in the absorbent core through the original three-dimensional structure.

[0034] Specifically, after the liquid comes into contact with the surface of the absorbent core, it can quickly penetrate into the absorbent core. When the liquid enters the space area where the middle layer 3 is located from the upper layer 1 or the lower layer 2, there are a large number of tiny spaces between the various connection positions in the three-dimensional structure - liquid storage cavities 11 formed by the dense division of vertical yarns 10. From a microscopic point of view, it is obvious that the number of these tiny spaces is very large and densely distributed. Moreover, any position in the three-dimensional structure where there is a connection relationship is a composite yarn body formed by the aggregation of fine filaments. Therefore, compared with the larger liquid storage cavities 11 that can be observed with the naked eye, the number of capillary-like spaces that are invisible to the naked eye is even greater. In this way, with the support of the above-mentioned intricate, interconnected, and numerous fine, velvety mesh-like micro-spaces, the intermolecular attraction between the liquid and the three-dimensional structure is quite obvious. The capillary phenomenon is easily induced by the above structure. Therefore, the liquid is not easy to seep back after it has penetrated into the absorbent core. Moreover, after the absorbent core has absorbed water, the liquid is preferentially adsorbed by the invisible capillary mesh-like space. The visible liquid storage cavity 11 and the opening 8 are preferentially guaranteed to be permeable, or most of them can be guaranteed to be permeable. Therefore, the absorbent core can still maintain a certain degree of air permeability after absorbing liquid.

[0035] Combination Figures 1 to 3As shown, furthermore, the three-dimensional structure of the absorbent core is also composited with absorbent fiber material, specifically referring to liquid storage particles 4. This structure is composed of at least one of artificial or natural fibers. Here, "natural or artificial fibers" refers to a situation where no other non-fiber materials are mixed in besides the fiber itself, as opposed to the later case of composited with SAP. Additionally, "natural fibers" refers to naturally occurring and directly usable materials like wood pulp fibers, while "artificial fibers" refers to artificially synthesized materials like viscose fibers, which are not naturally occurring. Both materials exhibit microscopic characteristics... It possesses hydrophilicity and intermolecular attraction to water molecules, thus enabling it to achieve the water absorption function of SAP polymer materials to a certain extent. In conjunction with the aforementioned microscopic three-dimensional structure, the synergy of the two can further enhance the adsorption stability of the liquid in the absorbent core. Since the liquid storage particles 4 can independently form small storage spaces with the vertical yarn 10 or the horizontal yarn 5, the microscopic contact area inside the entire absorbent core is much larger than that of the three-dimensional configuration without liquid storage particles 4, resulting in stronger liquid adsorption capacity. At the same time, it also takes into account the problem of not expanding due to water absorption. Due to the large presence of intermolecular attraction, the amount of liquid backflow on the surface of the absorbent core is also extremely low.

[0036] Reference Figure 3 As shown, based on this, if a small amount of SAP is added to the original single-material liquid storage microparticles 4, the liquid absorption capacity can be significantly improved on the basis of the original superior performance. It is worth mentioning that even if the SAP or absorbent fiber material absorbs water and swells, the three-dimensional structure of the absorbent core has a large tensile strength in its thickness direction. The space of the capillary-like web and the physical collision volume of the adjacent vertical yarns 10, horizontal yarns 5, and even natural or artificial fibers will limit the SAP in space. Therefore, even after absorbing water, the SAP makes it difficult for the absorbent core to show a surface shape expansion change that can be perceived by the naked eye, and gaps will always exist between the absorbent cores. The overall porosity is 65%-95%, and the volume of the liquid storage cavity 4 accounts for no less than 90% of the above porosity. This means that except for liquid escaping from the opening 8 or backflow, the liquid will always be within the range of the absorbent core. And due to the existence of the marginal effect, the gaps are generally not completely filled, which ensures that the breathable space always exists.

[0037] Based on the above, the application of SAP is no longer used to fill the entire space between the upper layer 1 and the lower layer 2. Therefore, in the three-dimensional configuration of the absorber core with the same weight and volume, the amount of SAP used will be much less than that of the absorber core filled with SAP alone. This greatly reduces the dependence on SAP and helps to reduce the difficulty of recycling and processing the absorber core after use.

[0038] Combination Figure 1 or Figure 2 As shown, as a further technical solution of this utility model, when the liquid storage microparticle 4 is a single natural fiber or a single synthetic fiber, the liquid storage microparticle 4 is fused and bonded or wrapped with the vertical yarn 10, fused and bonded or wrapped with one or more adjacent liquid storage microparticles 4, or free in the space of the liquid storage cavity 11. In the case that the liquid storage microparticle 4 does not contain any SAP, during the absorption core weaving process, the liquid storage microparticle 4 is connected to the vertical yarn 10 through a molten state or other external force. Once the liquid storage microparticle 4 forms a physical connection with the vertical yarn 10, it can serve as an anchor point for other free liquid storage microparticles 4 or other... The micro-capillary structures come into contact and further connect and combine, so that the liquid storage cavity 11 can be effectively divided into a large number of micro-capillary spaces like a velvet web. This is to meet the characteristics of the absorbent core having a strong intermolecular attraction for water molecules, as described in the previous embodiment. In the case of non-melting connection with other structures, the tightness of the entangled connection is poor, but its surface properties are not changed, so the water absorption is better. The free liquid storage particles 4 have a better water absorption effect, and in their floating state, they are more likely to make room in the liquid storage cavity 11 for local areas of the absorbent core, so that it can serve to allow for air permeability or maintain the overall shape stability of the absorbent core.

[0039] Combination Figures 1 to 3As shown, in one preferred embodiment of this utility model, when the liquid storage microparticles 4 are synthetic fibers or natural fibers composited with SAP, the synthetic fiber segments or natural fiber segments of the liquid storage microparticles 4 are fused and bonded to the vertical yarn 10 or wound as a whole, fused and bonded to one or more adjacent liquid storage microparticles 4, or free in the space of the liquid storage cavity. In the presence of SAP, to avoid the problem of detachment that occurs in conventional absorbent core structures due to the low peel force of SAP when it is not composited with the nonwoven fabric structure, the SAP is bonded to the absorbent core. Before the core is fully composited, it must be connected to any number of elemental liquid storage particles 4 through a molding process. The elemental liquid storage particles 4 have elemental length segments to achieve the same composite method as in the previous embodiment. In this structure, the SAP is better constrained by the structure of the elemental part of the liquid storage particles 4 and the horizontal yarn 5 and vertical yarn 10, resulting in better overall structural stability. It is not easily deformed by the expansion of the SAP after absorbing water. Furthermore, since the microscopic liquid storage particles 4 are not smooth and solid structures, the porosity can be guaranteed, and the air permeability will not be significantly negatively affected.

[0040] As one of the preferred embodiments of this utility model, when the liquid storage microparticles 4 are natural fibers or synthetic fibers, the length of a single liquid storage microparticle 4 is 0.5-50mm. The length of the liquid storage microparticles 4 should not be too long. If it is too long, it will obviously exceed the upper layer 1 or the lower layer 2. Under normal circumstances, it will cause a relatively subtle abnormal touch on the skin. This will be more obvious for infants and young children and may cause allergic reactions. Moreover, the melting contact area of ​​the liquid storage microparticles 4 that are too long may also be large, which is not conducive to the liquid storage microparticles 4 exerting their complete liquid absorption performance. If it is shorter than 0.5mm, it is actually equivalent to a single SAP particle, resulting in less performance differentiation and failing to clearly reflect the product characteristics of this utility model. If it exceeds 50mm, it will significantly affect the thickness and softness of the absorbent core, and the elasticity will also decrease compared to the length range mentioned above.

[0041] Combination Figures 4 to 6 As shown, in one preferred embodiment of this utility model, at least one opening in at least one of the upper layer 1 or lower layer 2 is formed by any two, three, or four horizontal yarns 5 interlacing and enclosing each other. This embodiment pertains to the weaving method of the upper layer 1 or lower layer 2. (Refer to...) Figure 4 As shown, in the case of two strands, the upper layer 1 or the lower layer 2 is more like a wavy, interwoven fabric pattern, and the shape of its opening 8 tends to be willow leaf-shaped, as shown in the reference. Figure 5 As shown, in the case of 3 roots, the shape tends to have a triangular opening of 8, see reference. Figure 6As shown, in the case of 4 horizontal yarns 5, the shape tends to be quadrilateral. The shape of the opening 8 does not significantly affect the absorption permeation speed of the absorbent core, but it will affect the number and density of the openings 8 in the absorbent core. The higher the density, the larger the relative contact area between the capillaries in each part of the absorbent core and the liquid water molecules, and the better the anti-backflow performance of the absorbent core.

[0042] As a further extension of the aforementioned set of embodiments, the fineness of the horizontal yarn 5 is 30-200D, and the F number is 12-288; the average fineness of the vertical yarn 10 is 10-200D, and the F number is 1-144; the weight of the matrix is ​​80-400gsm, and the thickness is 0.5-3.0mm. These parameters are adaptively set according to the softness, thinness, and resilience required by the thin absorbent core. The horizontal yarn of the upper layer 1... A higher denier (5) results in thicker yarn and smaller gaps between the horizontal yarns (5), leading to a longer liquid absorption time and a higher basis weight of the flow-guiding structure, and vice versa. Conversely, a higher denier (5) results in thicker yarn and smaller gaps between the horizontal yarns (5), leading to a longer liquid retention time within the three-dimensional structure, potentially resulting in higher backflow and a higher basis weight of the flow-guiding structure, and vice versa. In this embodiment, when the denier (5) and the vertical yarn (10) are... Based on the above values, the performance of the flow-guiding structure in the flat state is generally slightly inferior to the existing technology, and some indicators can be on par. However, in the bent state, the three-dimensional liquid absorption structure of this utility model can outperform or significantly outperform the existing technology in the test values ​​of each parameter node. For example, for absorbent products of NB size, compared with the conventional weight PE flow-guiding membrane used in existing products of the same size, under the same weight and length and width specifications, the flow-guiding structure described in this application, when compared with the following embodiment with the following specifications, uses horizontal yarn 5 of upper layer 1 and lower layer 2 with a fineness of 50D and a fiber count of 144, and vertical yarn 10 of middle layer 3 with a fineness of 40D and a fiber count of 120. After actual calculation, the softness performance is improved by up to 8.7%, the anti-backflow rate is also improved by 6.8%, and the flow-guiding penetration time is shortened by more than 23%.

[0043] Furthermore, after multiple measurements were conducted on the horizontal yarn 5 and the vertical yarn 10 according to their fineness relationship, with their physical parameters increasing linearly, it was found that as the fineness and fiber count of the horizontal yarn 5 and the vertical yarn 10 increased sequentially, when the fineness of the horizontal yarn 5 was between 50D and 75D and the fiber count was between 6 and 72, and the fineness of the vertical yarn 10 was between 10D and 60D and the fiber count was between 1 and 56, the changes in softness, anti-backflow rate, and permeation time were basically positively correlated function curves with a large slope and positive values. When the values ​​are within the ranges of 75D-150D, 72-144 yarns, 60D-120D, and 56-108 yarns, the changes in softness, anti-backflow rate, and flow-through time are basically within the curves of positive / negative values ​​with a small slope. The values ​​approach their peak values ​​when the horizontal yarn 5 and vertical yarn 10 are 120D and 108 yarns, and 100D and 72 yarns, respectively. Beyond these values, the changes in softness, anti-backflow rate, and flow-through time generally exhibit a negative correlation curve with a small slope and negative values.

[0044] Weight and thickness are parameters that directly reflect the overall appearance and performance of the absorbent core. They can be adapted to various specifications of absorbent products and will not significantly increase the weight or thickness of the absorbent products.

[0045] In summary, the absorbent core disclosed in this utility model, while reducing the application of SAP and maintaining good water absorption performance, greatly improves the surface dryness of the absorbent core and reduces the frequency of liquid backflow. It also has a certain degree of breathability, and the stuffiness is lower than that of existing general-configuration absorbent cores. The overall environmental protection level is also improved compared with existing general-configuration absorbent cores.

[0046] The above description is only a preferred embodiment of the present utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present utility model, and these improvements and modifications should also be considered within the protection scope of the present utility model.

Claims

1. An absorbent core with a velvet-textured sandwich structure, comprising a matrix with a three-dimensional structure, wherein the matrix is ​​composed of an upper layer, a middle layer, and a lower layer from top to bottom, characterized in that, The matrix also encapsulates liquid storage microparticles; The upper and lower layers are both formed by weaving several horizontal yarns to create a planar structure. Each upper or lower layer has a first plane and a second plane opposite to the first plane. The first and second planes tend to be flush in their own planar directions, and there is an opening between at least any two horizontal yarns in the same plane that connects the first and second planes. Any two horizontal yarns intersect each other and form nodes at the intersections. The middle layer is composed of several vertical yarns that are parallel to the normal direction of the first or second plane, or tend to be perpendicular to the normal direction and have an acute angle of ≤45° between them. The vertical yarns intersect or are connected with the horizontal yarns or nodes to form a three-dimensional structure, and the openings have no vertical yarns or only a small number of vertical yarns, so that the openings of the vertical yarns in the upper and lower layers account for less than 0.5% of the total number of openings. Between the upper and lower layers are several small, interconnected liquid storage cavities formed by vertical yarn division. The liquid storage microparticles are housed within the liquid storage cavities. The overall porosity of the matrix is ​​65-95%, and the volume of the liquid storage cavity accounts for no less than 90% of the overall porosity. The liquid storage microparticles are any one of natural fibers, synthetic fibers, synthetic fibers composited with SAP, or natural fibers composited with SAP.

2. The absorbent core with a velvet mesh sandwich structure according to claim 1, characterized in that, When the liquid storage microparticle is a single natural fiber or a single synthetic fiber, the liquid storage microparticle is fused and bonded or wrapped with the vertical yarn, fused and bonded or wrapped with one or more adjacent liquid storage microparticles, or free in the space of the liquid storage cavity.

3. The absorbent core with a velvet mesh sandwich structure according to claim 1, characterized in that, When the liquid storage microparticles are synthetic fibers or natural fibers composited with SAP, the synthetic fiber segments or natural fiber segments of the liquid storage microparticles are fused and bonded to the vertical yarn or wrapped as a whole, fused and bonded to or wrapped with one or more adjacent liquid storage microparticles, or free in the space of the liquid storage cavity.

4. The absorbent core with a velvet mesh sandwich structure according to claim 1, characterized in that, When the liquid storage microparticles are natural or synthetic fibers, the length of a single liquid storage microparticle is 0.5-50 mm.

5. The absorbent core with a velvet mesh sandwich structure according to claim 1, characterized in that, At least one of the openings in the upper or lower layer is formed by any two, three, or four horizontal yarns interlacing and enclosing each other.

6. The absorbent core with a velvet mesh sandwich configuration according to any one of claims 1 to 5, characterized in that, The fineness of the horizontal yarn is 30-200D, and the F number is 12-288.

7. The absorbent core with a velvet mesh sandwich configuration according to any one of claims 1 to 5, characterized in that, The vertical yarn has an average fineness of 10-200D and an F number of 1-144.

8. The absorbent core with a velvet mesh sandwich configuration according to any one of claims 1 to 5, characterized in that, The matrix has a basis weight of 80-400 gsm and a thickness of 0.5-3.0 mm.

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