Absorbent core with composite nonwoven

Abstract

The present application relates to the field of disposable sanitary products, and particularly relates to an absorbent core with composite non-woven fabric, comprising a body, the body comprising an upper fiber layer, a lower fiber layer and an intermediate fiber layer clamped between the upper fiber layer and the lower fiber layer, the upper fiber layer, the lower fiber layer and the intermediate fiber layer are bonded to each other to form a bonding part, the area of the bonding part accounts for 5-100% of the area of the body, the fiber thickness of the upper fiber layer and / or the lower fiber layer is 4-12D, the fiber thickness of the intermediate fiber layer is 0.6-2D, the upper fiber layer and the lower fiber layer are inlaid with high molecular water-absorbing particles, the average pore of the upper fiber layer and the lower fiber layer is greater than the average diameter of the high molecular water-absorbing particles, and the average pore of the intermediate fiber layer is smaller than the average diameter of the high molecular water-absorbing particles. The present application solves the technical problem that the high molecular is prone to loss when the absorbent core is made of fluffy non-woven fabric.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of disposable hygiene products, in particular to an absorbent core with composite nonwoven fabric. BACKGROUND

[0002] At present, people's living standards are getting better and better, and the comfort and functionality of disposable hygiene products are increasingly demanding, and the demand is also increasing. Among disposable hygiene products, fluffy nonwoven fabric is widely used, and the main application is the formation of the core. In the core forming process, fluffy nonwoven fabric is mainly used for carrying and embedding water-absorbing macromolecules. For example, a fluffy nonwoven fabric composite core disclosed in Chinese Patent Publication No. CN211512338U is composed of a first cover layer, a hot melt adhesive layer, a first superabsorbent resin layer, a high-fluffy nonwoven fabric layer, a second superabsorbent resin layer, a hot melt adhesive layer, and a second cover layer connected from top to bottom. The high-fluffy nonwoven fabric layer is composed of a surface layer, a bottom layer, and an intermediate layer between the surface layer and the bottom layer. The surface layer and the bottom layer are both long fiber web layers, and the intermediate layer is a mixed fiber web layer or a fluff pulp fiber web layer, and is connected with the adjacent bottom layer and surface layer as a whole. The mixed fiber web layer has a hot melt super fine short fiber web as a skeleton structure, and the fluff pulp fiber is fixedly combined in the hot melt super fine short fiber web. The long fiber web layer is a coarse denier fiber web layer, and the fiber size in the coarse denier fiber web layer is 3.0-10.0D, and the length is 38-51mm.

[0003] Under the existing process conditions, coarse denier fibers are used for both the upper layer and the lower layer of the fluffy fabric. Such fluffy fabric has large pores, which makes the product prone to deformation. This can cause the macromolecules to flow out during operation in the air-absorbing state, resulting in a decrease in macromolecules and poor absorption effect. The application in products will increase the production cost, thereby changing the quality of the product and reducing the absorbency and diffusivity of the core. SUMMARY

[0004] Therefore, in view of the above problems, the present application provides an absorbent core with composite nonwoven fabric, which solves the technical problem of easy macromolecule loss when using fluffy nonwoven fabric to make an absorbent core.

[0005] To achieve the above object, the present application adopts the following technical scheme: An absorbent core with a composite non-woven fabric, comprising a body, the body comprising an upper fiber layer, a lower fiber layer and an intermediate fiber layer clamped between the upper fiber layer and the lower fiber layer, the upper fiber layer, the lower fiber layer and the intermediate fiber layer are bonded to form a bonding part, the area of the bonding part accounts for 5-100% of the area of the body, the fiber thickness of the upper fiber layer and / or the lower fiber layer is 4-12D, the fiber thickness of the intermediate fiber layer is 0.6-2D, the basis weight of the upper fiber layer and / or the lower fiber layer is 5-50gsm, the basis weight of the intermediate fiber layer is 5-40gsm, the upper fiber layer and the lower fiber layer are embedded with high molecular water-absorbing particles, the average pore size of the upper fiber layer and the lower fiber layer is greater than the average diameter of the high molecular water-absorbing particles, and the average pore size of the intermediate fiber layer is less than the average diameter of the high molecular water-absorbing particles.

[0006] Further, the intermediate fiber layer comprises a dense area and a sparse area, the dense area accounts for 80-99% of the area of the intermediate fiber layer, and the remaining area is the sparse area.

[0007] Further, the sparse area has a basis weight of 5-7gsm, and the dense area has a basis weight of 8-40gsm.

[0008] Further, the thickness of the upper fiber layer and / or the lower fiber layer is 4-20 times the thickness of the intermediate fiber layer.

[0009] Further, the upper fiber layer and / or the lower fiber layer has a basis weight of 15gsm.

[0010] Further, the sparse area has a basis weight of 2-7gsm, and the dense area has a basis weight of 7-40gsm.

[0011] Further, the upper fiber layer, the lower fiber layer and the intermediate fiber layer are fluffy non-woven fabrics.

[0012] Further, the upper fiber layer, the lower fiber layer and the intermediate fiber layer are bonded by hot melt bonding, and the area of the bonding part accounts for 80-100% of the area of the body.

[0013] Further, the average pore size of the upper fiber layer and / or the lower fiber layer gradually decreases from the side close to the intermediate fiber layer to the outside and then gradually increases, and the average pore size of the upper fiber layer and / or the lower fiber layer is 1.2 times greater than the diameter of the high molecular water-absorbing particles.

[0014] Further, the upper fiber layer and / or the lower fiber layer comprises an inner loose layer, a middle tight layer, and an outer loose layer, the thickness of the inner loose layer: the thickness of the middle tight layer: the thickness of the outer loose layer is (8-10):(1-2):(4-5), and the average porosity of the inner loose layer: the average porosity of the middle tight layer: the average porosity of the outer loose layer is (2-3):1:(2-3).

[0015] By adopting the foregoing technical solutions, the present application has the following beneficial effects:

[0016] 1. The present application forms a composite by bonding the upper fiber layer, the middle fiber layer, and the lower fiber layer, wherein the fiber thickness of the upper fiber layer and / or the lower fiber layer is 4-12D, the fiber thickness of the middle fiber layer is 0.6-2D, the basis weight of the upper fiber layer and / or the lower fiber layer is 5-50gsm, and the basis weight of the middle fiber layer is 5-40gsm. The middle fiber layer is relatively dense compared to the upper fiber layer and the lower fiber layer, that is, the porosity of the upper fiber layer and the lower fiber layer is larger than that of the middle fiber layer. When the composite non-woven fabric is applied to the formation of the absorbent core, the high-molecular water-absorbing particles will be embedded in the upper fiber layer and the lower fiber layer and cannot penetrate the middle fiber layer, thereby achieving stable fixation of the high-molecular water-absorbing particles. The fiber thickness and basis weight of the middle fiber layer can be set according to actual needs to meet the performance of preventing specific high-molecular water-absorbing particles from penetrating. Specifically, the upper fiber layer, the middle fiber layer, and the lower fiber layer are fluffy non-woven fabrics.

[0017] 2、through the sparse area and the dense area, can effectively realize the middle fiber layer forms strip-shaped interval, that is, sparse area forms strip-shaped to realize the separation of dense area, this interval is obvious when the high molecular water-absorbing particles are sown or present more obvious difference, because the basis weight of the upper fiber layer and / or the lower fiber layer at the sparse area is similar to the basis weight of the middle fiber layer at the sparse area, that is, the gap is close, and even can be set to make the basis weight of the upper fiber layer and / or the lower fiber layer at the sparse area slightly smaller than the basis weight of the middle fiber layer at the sparse area, and the porosity of the two is also close, so that the high molecular has a larger free performance in this area, that is, it can realize the running between the upper fiber layer-middle fiber layer-lower fiber layer, but in fact, due to the characteristics of non-woven fabric, this running is not random, it has a greater restriction, so that when the high molecular is sown, the sparse area will form a region where the high molecular is more concentrated. Form a region with strong water absorption performance, thereby forming a channel with good flow continuity performance, and due to the high absorption performance of this part, it can also increase the water absorption performance in the dense area. The setting of the dense area and the sparse area can achieve the purpose of better separation, can also achieve the purpose of effective infiltration, and can also realize the stability of the shape after deformation. The sparse area has a basis weight of 5-7gsm, the dense area has a basis weight of 8-40gsm, specifically, the sparse area has a basis weight of 2-7gsm, and the dense area has a basis weight of 7-40gsm, which is a preferred choice.

[0018] 3、the upper fiber layer, the lower fiber layer, and the middle fiber layer are bonded by hot melt bonding, the area of the bonding part accounts for 80-100% of the area of the body, and the area of the bonding part is specifically limited to make the upper fiber layer and the middle fiber layer, and the lower fiber layer and the middle fiber layer have less deformable space, which can effectively prevent a large amount of deformable space from forming accumulation of high molecular water-absorbing particles. Of course, the combination of the bonding part can also reduce the butt joint of the high molecular water-absorbing particles, such as the bonding part forming a net structure, and multiple bonding parts forming a continuous polygonal structure.

[0019] 4. The average pore size of the upper fiber layer and / or the lower fiber layer gradually decreases from the side close to the intermediate fiber layer to the outside and then gradually increases, and the average pore size of the upper fiber layer and / or the lower fiber layer is greater than 1.2 times, preferably 1.5-2 times, the diameter of the high polymer water-absorbing particles. The upper fiber layer and / or the lower fiber layer comprises an inner loose layer, an intermediate tight layer, and an outer loose layer, and the thickness of the inner loose layer: the thickness of the intermediate tight layer: the thickness of the outer loose layer is (8-10): (1-2): (4-5), and the average pore size of the inner loose layer: the average pore size of the intermediate tight layer: the average pore size of the outer loose layer is (2-3): 1: (2-3). Such arrangement can achieve that the high polymer water-absorbing particles are first trapped in the outer loose layer, and the high polymer moves downward with the conveying and external vibration device, and more of the high polymer remains in the inner loose layer after passing through the intermediate tight layer, and can effectively prevent the high polymer water-absorbing particles from running outwards during conveying, transportation, and use. It can better achieve the stability of the high polymer water-absorbing particles. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 is a structural schematic diagram of embodiment one of the present application;

[0021] Figure 2 is a structural schematic diagram of embodiment two of the present application;

[0022] Figure 3 is a structural schematic diagram of the air flow hole and the loose area cooperation in embodiment two of the present application;

[0023] Figure 4 is a structural schematic diagram of embodiment three of the present application;

[0024] Figure 5 is a process flow diagram of the composite non-woven fabric of the present application;

[0025] Figure 6 is a process flow diagram of the forming of the absorbent core of the present application.

[0026] REFERENCE NUMERALS:

[0027] 1. upper fiber layer; 11. inner loose layer; 12. intermediate tight layer; 13. outer loose layer; 2. lower fiber layer; 3. intermediate fiber layer; 31. dense area; 32. loose area; 4. high polymer water-absorbing particles; 71. net blanket; 72. negative pressure adsorption area; 73. spreading device; 74. oscillation area; 741. upper metal plate; 742. lower metal plate; 8. body; 91. first carding machine; 92. first doffer; 93. second doffer; 94. second carding machine; 95. third doffer; 96. fourth doffer; 97. composite station; 98. oven; 961. air flow hole. DETAILED DESCRIPTION

[0028] The application will be further described in conjunction with the drawings and specific embodiments.

[0029] Reference Figure 1 The present embodiment one provides an absorbent core with composite non-woven fabric, comprising a body 8, the body 8 comprising an upper fiber layer 1, a lower fiber layer 2 and an intermediate fiber layer 3 clamped between the upper fiber layer 1 and the lower fiber layer 2, the upper fiber layer 1, the lower fiber layer 2 and the intermediate fiber layer 3 are bonded to each other to form a bonding part, the area of the bonding part accounts for 5-100% of the area of the body, the fiber fineness of the upper fiber layer 1 and / or the lower fiber layer 2 is 4-12D, specifically, it can be 8D or other values, the fiber fineness of the intermediate fiber layer 3 is 0.6-2D, specifically, it can be 1D or other values, the upper fiber layer 1 and / or the lower fiber layer 2 has a basis weight of 5-50gsm, the intermediate fiber layer 3 has a basis weight of 5-40gsm, the upper fiber layer 1 and the lower fiber layer 2 are embedded with high molecular water-absorbing particles 4, the average pore of the upper fiber layer 1 and the lower fiber layer 3 is greater than the average diameter of the high molecular water-absorbing particles 4, and the average pore of the intermediate fiber layer 3 is smaller than the average diameter of the high molecular water-absorbing particles 4.

[0030] The upper fiber layer, the lower fiber layer and the intermediate fiber layer clamped between the upper fiber layer and the lower fiber layer form a composite non-woven fabric.

[0031] Preferably, the upper fiber layer and / or the lower fiber layer can also have a basis weight of 15gsm, and the intermediate fiber layer has a basis weight of 8-9gsm. The upper fiber layer, the lower fiber layer and the intermediate fiber layer are bonded by hot melt bonding, and the area of the bonding part accounts for 80-100% of the area of the body. The ratio of the average pore diameter of the upper fiber layer and / or the lower fiber layer to the average pore diameter of the intermediate fiber layer is (2-5):1. The body has a basis weight of 15-120gsm. The body has a basis weight of 38-45gsm. The upper fiber layer, the lower fiber layer and the intermediate fiber layer are fluffy non-woven fabrics.

[0032] In addition, a surface layer can also be coated on the body, and the coating method can be to coat around the periphery or to coat only the upper layer and the lower layer.

[0033] The present scheme forms a composite through the adhesion of the upper fiber layer, the intermediate fiber layer, and the lower fiber layer, wherein the fiber thickness of the upper fiber layer and / or the lower fiber layer is 4-12D, the fiber thickness of the intermediate fiber layer is 0.6-2D, and the fiber layer and / or the lower fiber layer has a basis weight of 5-50gsm, and the intermediate fiber layer has a basis weight of 5-40gsm. Such an intermediate fiber layer will be relatively dense relative to the upper fiber layer and the lower fiber layer, that is, the porosity of the upper fiber layer and the lower fiber layer will be larger relative to the porosity of the intermediate fiber layer. When this composite non-woven fabric is applied to the formation of the absorbent core, the high molecular water-absorbing particles will be embedded in the upper fiber layer and the lower fiber layer and will not penetrate the intermediate fiber layer, thereby achieving stable fixation of the high molecular water-absorbing particles. The fiber thickness and basis weight of the intermediate fiber layer can be set according to actual needs to meet the performance of not being able to be penetrated by specific high molecular water-absorbing particles. Specifically, the upper fiber layer, the intermediate fiber layer, and the lower fiber layer are fluffy non-woven fabrics.

[0034] The upper fiber layer, the lower fiber layer, and the intermediate fiber layer are bonded by hot melt bonding, and the area of the bonding part accounts for 80-100% of the area of the body. Specifically, limiting the area of the bonding part can make the upper fiber layer and the intermediate fiber layer, and the lower fiber layer and the intermediate fiber layer have less deformable space, which can effectively prevent a large amount of deformable space from forming an accumulation of high molecular water-absorbing particles. Of course, the combination and arrangement of the bonding parts can also reduce the butt joint of high molecular water-absorbing particles, such as forming a mesh structure, and multiple bonding parts forming a continuous polygonal structure.

[0035] Reference Figure 2 which shows a structural schematic diagram of the intermediate fiber layer, and reference Figure 3 which shows a structural schematic diagram of the cooperation of the air flow hole and the sparse area. The present embodiment two provides an absorbent core with a composite non-woven fabric based on the same inventive concept, which is different from the first embodiment in that:

[0036] The intermediate fiber layer 3 includes a dense area 31 and a sparse area 32, and the dense area 31 accounts for 80-99% of the area of the intermediate fiber layer, and the remaining area is the sparse area 32. The thickness of the upper fiber layer and / or the lower fiber layer is 4-20 times the thickness of the intermediate fiber layer. The sparse area has a basis weight of 2-7gsm, and the dense area has a basis weight of 7-40gsm. Specifically, the sparse area has a basis weight of 3gsm, and the dense area has a basis weight of 8-9gsm.

[0037] The formation of the sparse zone involves setting airflow holes below the sparse zone during molding. Airflow is emitted from the airflow holes 961, which are elongated. The width A of the airflow holes 961 is less than half the width B of the sparse zone 32. The distance C between the airflow holes and the edge of the sparse zone is such that when the airflow is blown out and diffuses outward, it will not obstruct the fiber stacking in the dense zone.

[0038] The intermediate fiber layer can be a single-layer structure or a double-layer structure. When the intermediate fiber layer is a double-layer structure, the intermediate fiber layer is staggered and bonded along the conveying direction during the composite process. The length of the staggered bonding is not less than 1 mm, and the optimal length is 5 mm.

[0039] By setting up sparse and dense zones, strip-like intervals can be effectively formed in the intermediate fiber layer. This separation of the dense zone from the sparse zone creates a noticeable difference when spreading the superabsorbent polymer particles. This is because the basis weight of the upper and / or lower fiber layers in the sparse zone is similar to that of the intermediate fiber layer, meaning their spacing is close. Furthermore, the basis weight of the upper and / or lower fiber layers in the sparse zone can be set to be slightly less than that of the intermediate fiber layer, and their pore sizes are also similar. This allows the superabsorbent polymer to have greater freedom of movement in this area, enabling partial penetration. The movement between the upper, middle, and lower fiber layers is not arbitrary due to the characteristics of nonwoven fabric; it is subject to significant constraints. Consequently, during superabsorbent polymer spreading, the sparse zone becomes a region where the superabsorbent polymer is more concentrated. This creates a region with strong water absorption, forming a channel with good continuous flow performance. Furthermore, the high absorption capacity of this area also increases the water absorption capacity within the densely packed zone. The separation of the densely packed and sparsely packed zones achieves good separation, effective infiltration, and stability of the deformed shape. The sparsely packed zone has a basis weight of 5-7 gsm, and the densely packed zone has a basis weight of 8-40 gsm. Specifically, a basis weight of 2-7 gsm for the sparsely packed zone and 7-40 gsm for the densely packed zone is preferred.

[0040] See again Figure 4 It conceals superabsorbent polymer particles. The difference between this third embodiment and the first or second embodiment is:

[0041] The average pore size of the upper fiber layer 1 and / or the lower fiber layer 2 gradually decreases from the side close to the intermediate fiber layer 3 to the outside and then gradually increases, and the average pore size of the upper fiber layer and / or the lower fiber layer is greater than 1.2 times the diameter of the polymer water-absorbing particles. The upper fiber layer and / or the lower fiber layer comprises an inner loose layer 11, an intermediate dense layer 12, and an outer loose layer 13, and the thickness of the inner loose layer: the thickness of the intermediate dense layer: the thickness of the outer loose layer is (8-10):(1-2):(4-5), and the average pore size of the inner loose layer: the average pore size of the intermediate dense layer: the average pore size of the outer loose layer is (2-3):1:(2-3).

[0042] Such arrangement can achieve that the polymer water-absorbing particles are first clamped in the outer loose layer, and the polymer moves downward through the intermediate dense layer and is retained in the inner loose layer, and can effectively prevent the polymer water-absorbing particles from running outwards during transportation, transportation, and use. It can better achieve the stability of the polymer water-absorbing particles.

[0043] Referring again to Figure 5 , the forming process of the composite non-woven fabric comprises:

[0044] In the first step, the fibers are output by the first carding machine 91, and the fibers are output to form the upper fiber layer through the first doffer 92, and / or the fibers are output to form the lower fiber layer through the second doffer 93;

[0045] In the second step, the fibers are output by the second carding machine 94, and the fibers are output to form the intermediate fiber layer through the third doffer 95 and / or the fourth doffer 96;

[0046] In the third step, the upper fiber layer, the intermediate fiber layer, and the lower fiber layer are combined in the composite station 97 to form the body, and the ratio of the average pore size of the upper fiber layer and / or the lower fiber layer to the average pore size of the intermediate fiber layer is (2-10):1;

[0047] In the fourth step, the oven 98 is input to perform hot melt bonding, so as to realize the mutual bonding of the upper fiber layer, the lower fiber layer, and the intermediate fiber layer to form the bonding part, and the area of the bonding part accounts for 5-100% of the area of the body.

[0048] Among them, the intermediate fiber can be one layer of fiber or two layers of fiber, and when the fiber is two layers, hot melt bonding is used between the two layers of fiber.

[0049] When forming the intermediate fiber layer, a directional spinning process is used to form a loose area and a dense area, and the shape of the loose area and the dense area can be set according to actual needs, such as Figure 2The strip-shaped structure can also be S-shaped, diamond-shaped, grid-shaped, etc. When forming the isolation zone, the air flow is increased at the third and / or fourth doffer in such a way that the air flow blows from bottom to top, thereby effectively forming a certain air flow resistance above the isolation zone, thereby reducing the fibers falling into the isolation zone, thereby forming the isolation zone. By adjusting the size of the air flow, the stacking thickness and density of the isolation zone can be adjusted.

[0050] The present scheme outputs fibers through the second carding machine to form an intermediate fiber layer, wherein the intermediate fiber layer can be a single-layer structure or a double-layer structure. The upper fiber layer, the intermediate fiber layer, and the lower fiber layer are combined at a composite station to form a body, and the body is input into an oven for hot melt bonding, so as to realize mutual bonding of the upper fiber layer, the lower fiber layer, and the intermediate fiber layer to form a bonding part, the area of the bonding part accounts for 5-100% of the area of the body. The ratio of the average porosity of the upper fiber layer and / or the lower fiber layer to the average porosity of the intermediate fiber layer is (2-10):1, so that the high molecular particles can enter the upper fiber layer and the lower fiber layer but cannot penetrate the intermediate fiber layer.

[0051] When the upper fiber layer and / or the lower fiber layer need different average porosities, it can be realized by adjusting the number, speed, etc. of the jet.

[0052] Referring again to Figure 6 On the basis of forming the composite non-woven fabric, high molecular particles are sown,

[0053] The composite non-woven fabric passes through a net blanket, air suction is performed below the net blanket, and high molecular water-absorbing particles are sown on the upper fiber layer by using adsorption. In this process, the adsorption force and the moving speed can be adjusted according to actual needs. Then, after turning over and turning over, sowing is performed on the other side, that is, sowing is performed on the lower fiber layer.

[0054] Of course, in this process, the high molecular water-absorbing particles sown twice can be different, as long as they do not pass through the intermediate fiber layer to a large extent. The high molecular water-absorbing particles with corresponding properties can be selected according to actual needs.

[0055] In addition, in order to realize the rapid entry of high molecular water-absorbing particles, the sowing and stabilization of high molecular water-absorbing particles can be performed by using the combined action of oscillation and negative pressure adsorption.

[0056] Specifically, the production process of the absorbent core with the composite non-woven fabric is as follows:

[0057] In the first step, the composite non-woven fabric is laid on the net blanket 71, and then conveyed;

[0058] Second step, the net blanket 71 passes through the negative pressure adsorption area 72, the negative pressure adsorption area 72 carries out negative pressure adsorption under the net blanket, at the same time, above the negative pressure adsorption area, the net blanket is sowed with high polymer water absorption particles by sowing device 73;

[0059] Third step, the net blanket passes through the oscillation area 74, the vibration area oscillates the net blanket.

[0060] The oscillation area has upper metal plate 741 and lower metal plate 742, the upper metal plate and the lower metal plate clamp the net blanket and the composite non-woven fabric on the net blanket, the clamping state makes the thickness direction deformation of the composite non-woven fabric 5-20%, then the lower metal plate and / or the upper metal plate oscillate, the oscillation time is selected according to actual needs, the oscillation direction is first oscillated in the vertical direction, and then oscillated in the left and right directions.

[0061] Although the present application is specifically shown and described in connection with the preferred embodiments, those skilled in the art will appreciate that various modifications in form and details are possible without departing from the spirit and scope of the application as defined by the appended claims.

Claims

1. An absorbent core with a composite nonwoven fabric, characterized in that: The device includes a body comprising an upper fiber layer, a lower fiber layer, and an intermediate fiber layer sandwiched between the upper and lower fiber layers. The upper, lower, and intermediate fiber layers are bonded together to form an adhesive portion, the area of ​​which accounts for 5-100% of the body area. The fiber thickness of the upper and / or lower fiber layers is 4-12D, the fiber thickness of the intermediate fiber layer is 0.6-2D, the upper and / or lower fiber layers have a basis weight of 5-50 gsm, the intermediate fiber layer has a basis weight of 5-40 gsm, and superabsorbent polymer particles are embedded within the upper and lower fiber layers. The average porosity of the upper and lower fiber layers is greater than the average diameter of the superabsorbent polymer particles, and the average porosity of the intermediate fiber layer is smaller than the average diameter of the superabsorbent polymer particles. The intermediate fiber layer includes a dense region and a sparse region, with the dense region accounting for 80-99% of the area of ​​the intermediate fiber layer and the remaining area being the sparse region. The average pore size of the upper fiber layer and / or lower fiber layer gradually decreases and then gradually increases from the side closer to the middle fiber layer outwards, and the average pore size of the upper fiber layer and / or lower fiber layer is greater than 1.2 times the diameter of the polymer water-absorbing particles. The upper fiber layer and / or lower fiber layer include an inner loose layer, an intermediate dense layer, and an outer loose layer. The thickness of the inner loose layer: the thickness of the intermediate dense layer: the thickness of the outer loose layer is (8-10): (1-2): (4-5). The average porosity of the inner loose layer: the average porosity of the intermediate dense layer: the average porosity of the outer loose layer is (2-3): 1: (2-3).

2. The absorbent core with composite nonwoven fabric according to claim 1, characterized in that: The sparse zone has a basis weight of 5-7 gsm, and the dense zone has a basis weight of 8-40 gsm.

3. The absorbent core with composite nonwoven fabric according to claim 1, characterized in that: The thickness of the upper fiber layer and / or the lower fiber layer is 4-20 times the thickness of the middle fiber layer.

4. The absorbent core with composite nonwoven fabric according to claim 1, characterized in that: The upper fiber layer and / or lower fiber layer have a basis weight of 15 gsm.

5. The absorbent core with composite nonwoven fabric according to claim 1, characterized in that: The sparse zone has a basis weight of 2-7 gsm, and the dense zone has a basis weight of 7-40 gsm.

6. The absorbent core with composite nonwoven fabric according to claim 1, characterized in that: The upper fiber layer, lower fiber layer, and middle fiber layer are made of fluffy nonwoven fabric.

7. The absorbent core with composite nonwoven fabric according to claim 1, characterized in that: The upper fiber layer, lower fiber layer, and middle fiber layer are bonded together by hot melt bonding, and the area of ​​the bonded part accounts for 80-100% of the body area.

Images