Thin adult paper diaper and preparation method thereof

Abstract

The invention relates to the field of hygienic products, provides a thin adult paper diaper and a preparation method thereof, and solves the problems that an adult paper diaper prepared in the prior art is insufficient in instant absorption speed to cause urine leakage, is too thick to cause stuffiness and is relatively high in preparation cost. Comprising a paper diaper body, the paper diaper body is of a single-core structure and comprises a liquid-tight bottom layer on the lower layer, an absorption core layer on the middle layer and a surface layer on the upper layer, the absorption core layer comprises a fluff pulp core layer and a composite core layer, a groove is formed in a middle core absorption area of the fluff pulp core layer, and the fluff pulp core layer is arranged in the groove. The composite core body layer is embedded into the groove or covers the groove; an area a, an area b and an area c are arranged on the absorption core layer in the length direction of the absorption core layer, the area b is symmetrically arranged on the left side and the right side of the area a, and the area c is symmetrically arranged on the upper side and the lower side of the area a and the area b.

Description

Technical Field

[0001] The present invention relates to the field of sanitary products, in particular to a thin adult diaper and a preparation method thereof. Background Art

[0002] Baby diapers on the market primarily feature SAP composite cores. Compared to traditional fluff pulp + SAP blends, composite cores are thinner and lighter. The tight integration of SAP and nonwoven fabric reduces breakage and bunching. After absorbing water, the core expands overall without bunching, maintaining good breathability, reducing stuffiness, and improving comfort. Adults and infants have different urination characteristics. Adults urinate in large volumes and at high rates, so using composite cores alone may result in insufficient absorption and the risk of leakage. Furthermore, adult diapers have large core areas, and using composite cores exclusively is relatively costly. Current composite core adult diapers are mostly constructed with a composite core (upper core) + fluff pulp + SAP (lower core). While this dual-layer core structure partially leverages the composite core's advantages of high absorption capacity and lack of bunching, it still doesn't address the product's bulk and stuffiness. Therefore, developing a lightweight, high-absorbency adult diaper could effectively enhance the consumer experience.

[0003] Chinese patent application number CN202111380905.2 discloses a process for preparing a composite absorbent core for diapers, comprising the preparation of a lower polylactic acid fiber web, an absorbent layer, an upper polylactic acid fiber web, needling lamination, thermal bonding reinforcement, ironing, slitting, and winding into a finished product; the absorbent layer comprises a super absorbent resin and wood pulp fiber layer laid in an upper and lower layer order. By preparing a three-dimensionally distributed polylactic acid fiber web, laminating it with a lower polylactic acid spunbond non-woven fabric, uniformly spraying SAP and distributing it uniformly in the composite polylactic acid fiber web, and finally laminating it with a polylactic acid meltblown ultrafine fiber web, the process of thermal reinforcement and spraying super absorbent resin is selected. The prepared composite absorbent core has good air permeability, moisture permeability, and comfort, does not contain hot melt adhesive, has a high SAP utilization rate, good absorption capacity, and more importantly, is biodegradable, which can effectively solve the problem of disposable sanitary products not being degraded after use. However, the absorbent layer of the diaper has a structure in which the upper layer is a super absorbent resin and the lower layer is a wood pulp fiber layer. The product has the disadvantage of being too thick and easily causing a stuffy feeling.

[0004] Chinese patent application number CN202211451383.5 discloses a method for preparing an absorbent core and an absorbent core, comprising: laying a lower covering layer; laying a SAP blend on the lower covering layer, wherein the SAP blend is formed by mixing SAP, chitosan quaternary ammonium salt and chitosan in a mass ratio of 18-22:2.5-4.5:0.8-2; spraying water or saline on the SAP blend; high-temperature melt-blown spinning is laid on the SAP blend to form a melt-blown layer, and blended with at least a portion of SAP. The SAP blend, formed by mixing chitosan, chitosan quaternary ammonium salt, and super absorbent resin, is self-adhesive. On the one hand, it can adhere to the meltblown layer and the lower cover layer without the use of industrial hot melt adhesive, thereby increasing the absorption rate. At the same time, during the process, due to the positive polarity of chitosan and the negative polarity of the meltblown layer, it is easier to form a bond. The wind pressure generated by the meltblown fabric weaving process can be used to adhere, and the high temperature generated during the process can be used to adhere, which rationally utilizes the energy generated during the production process and saves overall energy consumption. However, the amount of SAP used in this absorbent core is relatively large, and the preparation cost is relatively high. Summary of the Invention

[0005] Therefore, in response to the above problems, the present invention provides a thin adult diaper and a preparation method thereof, which solves the problems of adult diapers prepared by the prior art, such as insufficient instantaneous absorption speed leading to urine leakage, thick products prone to causing stuffiness, and relatively high preparation costs.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] A thin adult diaper includes a diaper body, which is a single-core structure, including a liquid-impermeable bottom layer, an absorbent core layer in the middle layer, and an upper surface layer. The absorbent core layer includes a fluff pulp core layer and a composite core layer. The middle core absorption area of the fluff pulp core layer is provided with a groove. The composite core layer is embedded in the groove or covers the groove. The distance between the composite core layer and the edges of the grooves on all sides is ≤50mm. Area a, area b, and area c are arranged on the absorbent core layer along the length direction of the absorbent core layer. The area b is symmetrically arranged on the left and right sides of area a, and the area c is symmetrically arranged on the upper and lower sides of area a and area b.

[0008] Furthermore, when the composite core layer is embedded in the groove, the width of the composite core layer is ≤ the width of the groove, the length of the composite core layer is ≤ the length of the groove, and the distance between the composite core layer and the edges of the groove on all sides is ≤50 mm.

[0009] Furthermore, when the composite core layer covers the groove, the width of the composite core layer is greater than the width of the groove, and the length of the composite core layer is greater than the length of the groove.

[0010] Furthermore, the SAP content of the region a is greater than or equal to the SAP content of the region c; the SAP liquid permeability speed of the region a is greater than or equal to the SAP liquid permeability speed of the region c, and the SAP liquid permeability speed of the region b is greater than or equal to the SAP liquid permeability speed of the region c.

[0011] Furthermore, the length of the composite core is 25%-85% of the length of the fluff pulp core layer, and the width of the composite core is 30%-90% of the width of the fluff pulp core layer.

[0012] Furthermore, the structure of the composite core has ≥3 layers, and the composite core is formed by alternating layers of a first material layer and SAP; the first material layer is any one of non-woven fabric, toilet paper or fiber web.

[0013] Furthermore, the composite core has a grammage of 80gsm-600gsm.

[0014] Furthermore, a guide groove is provided on the surface of the surface layer.

[0015] A method for preparing thin adult diapers comprises the following steps:

[0016] S1. Preparation of a fluff pulp core layer: crushing the fluff pulp and uniformly mixing the fluff pulp and SAP polymer material in a weight ratio of (0.5-8): (2-9.5) to form a mixed slurry, and negatively adsorbing the mixed slurry into a first forming die wheel. The first forming die wheel is provided with a baffle to control the middle core absorption zone from falling out of the mixed slurry. After forming, demolding is performed to obtain a fluff pulp core layer with a groove;

[0017] S2. Preparation of a composite core layer: The composite core layer is prepared in a second molding die wheel. A pressure-dividing zone is provided in the mold cavity of the second molding die wheel. The pressure-dividing zone includes a first pressure zone, a second pressure zone, and a third pressure zone. The negative pressure strength of the first pressure zone is adjusted to be ≥30% greater than the negative pressure strength of the third pressure zone. The SAP polymer material is adsorbed in the pressure-dividing zone. The non-woven fabric layer is unwound and conveyed. The SAP polymer material is spread online at a fixed point on the surface of the non-woven fabric layer. A non-woven fabric layer is then laminated online. The composite core layer is subjected to a pressure roller lamination process to obtain a non-woven fabric layer-SAP layer-non-woven fabric layer structure from top to bottom.

[0018] S3. Compounding: The composite core layer obtained in step S2 is transferred online and filled into the groove of the fluff pulp core layer obtained in step S1 to obtain an absorbent core layer. The surface layer, the absorbent core layer and the liquid-impermeable bottom layer are compounded into one to obtain the thin adult diaper.

[0019] Furthermore, a method for preparing a thin adult diaper comprises the following steps:

[0020] I. Preparation of a fluff pulp core layer: crushing the fluff pulp and uniformly mixing the fluff pulp and SAP polymer material in a weight ratio of (0.5-8): (2-9.5) to form a mixed slurry, and negatively adsorbing the mixed slurry into a first forming die wheel. The first forming die wheel is provided with a baffle to control the middle core absorption zone from falling out of the mixed slurry. After forming, demolding is performed to obtain a fluff pulp core layer with a groove;

[0021] II. Preparation of a semi-finished composite core layer: The semi-finished composite core layer is prepared in a second forming die wheel. A pressure-dividing zone is provided in the die cavity of the second forming die wheel. The pressure-dividing zone includes a first air pressure zone, a second air pressure zone, and a third air pressure zone. The negative pressure intensity of the first air pressure zone is adjusted to be ≥30% higher than the negative pressure intensity of the third air pressure zone. The SAP polymer material is adsorbed in the pressure-dividing zone, the non-woven fabric layer is unwound and conveyed, the SAP polymer material is spread online at a fixed point on the surface of the non-woven fabric layer, and then a non-woven fabric layer is composited online. The non-woven fabric layer is subjected to a pressure roller lamination process to obtain a semi-finished composite core layer having a structure of non-woven fabric layer-SAP layer-non-woven fabric layer from top to bottom;

[0022] III. Preparation of the composite core layer: Adsorbing the SAP polymer material in another second forming die wheel, adjusting the negative pressure intensity of the first air pressure zone to be ≥30% greater than the negative pressure intensity of the third air pressure zone, unwinding and conveying the non-woven fabric layer, and spreading the SAP polymer material on the surface of the non-woven fabric layer at a fixed point online to obtain a non-woven fabric layer with the SAP polymer material spread on the surface, which is then composited with the semi-finished composite core layer to obtain a composite core layer consisting of non-woven fabric layer-SAP layer-non-woven fabric layer-SAP layer-non-woven fabric layer from top to bottom;

[0023] IV. Compounding: The composite core layer prepared in step III is transferred online and filled into the groove of the fluff pulp core layer prepared in step I to obtain an absorbent core layer. The surface layer, the absorbent core layer and the liquid-impermeable bottom layer are compounded into one to obtain the thin adult diaper.

[0024] By adopting the above technical solution, the beneficial effects of the present invention are:

[0025] 1. The product's central core absorption area is a composite core layer, while the surrounding auxiliary absorption areas are fluff pulp core layers (fluff pulp + SAP). The composite core layer has a high SAP content, resulting in a large absorption capacity, strong water-locking properties, and excellent dryness after absorption. The surrounding fluff pulp absorbs quickly, effectively preventing urine leakage.

[0026] 2. By adopting the method of fixed-point spreading of SAP, the diversion channel can be designed according to the flow characteristics of urine in diapers; SAP fixed-point spreading can divide SAP into small unit modules, and set gaps between each module. Compared with traditional continuous or intermittent spreading, there are more gaps between SAP, which is conducive to the diffusion of urine; the combination of molds can be used to design different areas with different SAP weights, SAP models and corresponding absorption properties.

[0027] 3. The central core absorption area of the fluff pulp core layer is grooved, and the composite core layer is embedded within or covers the groove, effectively solving the product's shortcomings of being thick and stuffy. Compared to traditional adult diapers that use an all-SAP composite core, this product can significantly reduce costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 2 is a schematic plan view of the absorbent core layer of an adult diaper according to an embodiment of the present invention;

[0029] Figure 2 This is a diagram showing the regional arrangement of the absorbent core layer in an embodiment of the present invention;

[0030] Figure 3 Schematic diagram of the structure of the absorbent core layer in an embodiment of the present invention;

[0031] Explanation of the numbers in the figure: 1- fluff pulp core layer, 2- composite core layer, 11- groove. DETAILED DESCRIPTION

[0032] Example 1

[0033] refer to Figures 1 to 3 A thin adult diaper includes a diaper body, which is a single-core structure, including a liquid-impermeable bottom layer, an absorbent core layer in the middle layer, and an upper surface layer. The absorbent core layer includes a fluff pulp core layer 1 and a composite core layer 2. The middle core absorption area of the fluff pulp core layer 1 is provided with a groove 11, and the composite core layer 2 is embedded in the groove 11. The upper surface of the composite core layer 2 is flush with the upper surface of the fluff pulp core layer 1, and the distance between the composite core layer and the edges of the grooves on all sides is 50 mm; area a, area b, and area c are set on the absorbent core layer along the length direction of the absorbent core layer, the area b is symmetrically arranged on the left and right sides of area a, and the area c is symmetrically arranged on the upper and lower sides of area a and area b.

[0034] The width of the composite core layer is less than the width of the groove, and the length of the composite core layer is less than the length of the groove. That is, a groove is dug in the middle core absorption area of the fluff pulp core layer, and a composite core layer with a width and length smaller than the groove is filled in. The gap design optimizes liquid conductivity: the gap structure can form a vertical downward rapid diversion channel, and the liquid directly penetrates to the bottom of the composite core layer through the gap at the edge of the groove, breaking through the limitation of traditional planar absorption layers relying on lateral diffusion. The gap between the composite core layer and the groove can absorb the material expansion stress. When the composite core layer absorbs liquid and expands, the gap space provides a deformation buffer for it, preventing the core structure from being damaged due to excessive extrusion.

[0035] The SAP content of the region a is greater than the SAP content of the region c.

[0036] The SAP liquid permeability speed of the region a is greater than the SAP liquid permeability speed of the region c, and the SAP liquid permeability speed of the region b is greater than the SAP liquid permeability speed of the region c.

[0037] The length of the composite core is 60% of the length of the fluff pulp core layer.

[0038] The width of the composite core is 30% of the width of the fluff pulp core layer.

[0039] The composite core has a three-layer structure, including a non-woven fabric layer, a SAP layer, and a non-woven fabric layer stacked in sequence from top to bottom.

[0040] The composite core has a grammage of 80 gsm.

[0041] The method for preparing the thin adult diaper described above comprises the following steps:

[0042] S1. Preparation of a fluff pulp core layer: crushing the fluff pulp and uniformly mixing the fluff pulp and SAP polymer material in a weight ratio of 0.5:2 to form a mixed slurry, and negatively adsorbing the mixed slurry into a first forming die wheel. The first forming die wheel is provided with a baffle to control the middle core absorption zone from falling into the mixed slurry. After forming, demolding is performed to obtain a fluff pulp core layer with a groove;

[0043] S2. Preparation of a composite core layer: The composite core layer is prepared in a second forming die wheel. A pressure-dividing zone is provided in the die cavity of the second forming die wheel. The pressure-dividing zone includes a first pressure zone, a second pressure zone, and a third pressure zone. The negative pressure strength of the first pressure zone is adjusted to 30% of the negative pressure strength of the third pressure zone. The SAP polymer is adsorbed in the pressure-dividing zone. The non-woven fabric layer is unwound and conveyed. The SAP polymer is spread online at a fixed point on the surface of the non-woven fabric layer. A non-woven fabric layer is then laminated online. The non-woven fabric layer is subjected to a pressure roller lamination process to obtain the composite core layer having a structure of non-woven fabric layer-SAP layer-non-woven fabric layer from top to bottom.

[0044] S3. Compounding: The composite core layer obtained in step S2 is transferred online and filled into the groove of the fluff pulp core layer obtained in step S1 to obtain an absorbent core layer. The surface layer, the absorbent core layer and the liquid-impermeable bottom layer are compounded into one to obtain the thin adult diaper.

[0045] Example 2

[0046] A thin adult diaper includes a diaper body, which has a single-core structure and includes a liquid-impermeable bottom layer, an absorbent core layer in the middle layer, and a surface layer in the upper layer. The absorbent core layer includes a fluff pulp core layer and a composite core layer. The middle core absorption area of the fluff pulp core layer is provided with a groove, and the composite core layer covers the groove. Area a, area b, and area c are arranged on the absorbent core layer along the length direction of the absorbent core layer, the area b is symmetrically arranged on the left and right sides of area a, and the area c is symmetrically arranged on the upper and lower sides of area a and area b.

[0047] The width of the composite core layer is greater than the width of the groove, and the length of the composite core layer is greater than the length of the groove.

[0048] The SAP content of the region a is greater than the SAP content of the region b.

[0049] The SAP liquid permeability speed of the region a is greater than the SAP liquid permeability speed of the region c, and the SAP liquid permeability speed of the region b is greater than the SAP liquid permeability speed of the region c.

[0050] The length of the composite core is 60% of the length of the fluff pulp core layer.

[0051] The width of the composite core is 30% of the width of the fluff pulp core layer.

[0052] The composite core has a five-layer structure, including a non-woven fabric layer, a SAP layer, a non-woven fabric layer, a SAP layer, and a non-woven fabric layer stacked in sequence from top to bottom.

[0053] The composite core has a grammage of 200 gsm.

[0054] The method for preparing the thin adult diaper described above comprises the following steps:

[0055] I. Preparation of a fluff pulp core layer: crushing the fluff pulp and uniformly mixing the fluff pulp and SAP polymer material in a weight ratio of 4:5.5 to form a mixed slurry, and negatively adsorbing the mixed slurry into a first forming die wheel. The first forming die wheel is provided with a baffle to control the middle core absorption zone from falling out of the mixed slurry. After forming, demolding is performed to obtain a fluff pulp core layer with a groove;

[0056] II. Preparation of a semi-finished composite core layer: The semi-finished composite core layer is prepared in a second forming die wheel. A pressure-dividing zone is provided in the die cavity of the second forming die wheel. The pressure-dividing zone includes a first air pressure zone, a second air pressure zone, and a third air pressure zone. The negative pressure strength of the first air pressure zone is adjusted to 30% of the negative pressure strength of the third air pressure zone. The SAP polymer material is adsorbed in the pressure-dividing zone, the non-woven fabric layer is unwound and conveyed, the SAP polymer material is spread online at a fixed point on the surface of the non-woven fabric layer, and then a non-woven fabric layer is composited online. The non-woven fabric layer is subjected to a pressure roller lamination process to obtain a semi-finished composite core layer having a structure of non-woven fabric layer-SAP layer-non-woven fabric layer from top to bottom;

[0057] III. Preparation of a composite core layer: Adsorbing a SAP polymer material into another second forming die wheel, adjusting the negative pressure strength of the first air pressure zone to 30% of the negative pressure strength of the third air pressure zone, unwinding and conveying the non-woven fabric layer, and spreading the SAP polymer material online at a fixed point on the surface of the non-woven fabric layer to obtain a non-woven fabric layer with the SAP polymer material spread on the surface, which is then composited with the semi-finished composite core layer to obtain a composite core layer consisting of non-woven fabric layer-SAP layer-non-woven fabric layer-SAP layer-non-woven fabric layer from top to bottom;

[0058] IV. Compounding: The composite core layer prepared in step III is transferred online and filled into the groove of the fluff pulp core layer prepared in step I to obtain an absorbent core layer. The surface layer, the absorbent core layer and the liquid-impermeable bottom layer are compounded into one to obtain the thin adult diaper.

[0059] Example 3

[0060] The difference from Example 1 is that the composite core layer in step S2 is prepared in advance off-line, and then filled into the grooves of the fluff pulp core layer to obtain the absorbent core layer, and then the surface layer, the absorbent core layer and the liquid-impermeable bottom layer are compounded into one to obtain the thin adult diaper.

[0061] Although the present invention has been particularly shown and described in conjunction with preferred embodiments, it will be understood by those skilled in the art that various changes in form and details may be made to the present invention without departing from the spirit and scope of the invention as defined in the appended claims, and all such changes are within the scope of protection of the present invention.

Claims

1. A thin adult diaper, characterized by: The invention comprises a diaper body, which is a single-core structure, including a liquid-impermeable bottom layer, an absorbent core layer in the middle layer and a surface layer in the upper layer. The absorbent core layer comprises a fluff pulp core layer and a composite core layer. The middle core absorption area of the fluff pulp core layer is provided with a groove, and the composite core layer is embedded in the groove or covers the groove. Area a, area b and area c are arranged on the absorbent core layer along the length direction of the absorbent core layer, and the area b is symmetrically arranged on the left and right sides of the area a, and the area c is symmetrically arranged on the upper and lower sides of the area a and the area b.

2. A thin adult diaper according to claim 1, characterized in that: The width of the composite core layer is less than or equal to the width of the groove, the length of the composite core layer is less than or equal to the length of the groove, and the distance between the composite core layer and the edges of the grooves on all sides is less than or equal to 50 mm.

3. The thin adult diaper according to claim 1, characterized in that: The width of the composite core layer is greater than the width of the groove, and the length of the composite core layer is greater than the length of the groove.

4. The thin adult diaper according to claim 1, characterized in that: The SAP content of the region a is greater than or equal to the SAP content of the region c; the SAP liquid permeability speed of the region a is greater than or equal to the SAP liquid permeability speed of the region c, and the SAP liquid permeability speed of the region b is greater than or equal to the SAP liquid permeability speed of the region c.

5. The thin adult diaper according to claim 1, characterized in that: The length of the composite core is 25%-85% of the length of the fluff pulp core layer, and the width of the composite core is 30%-90% of the width of the fluff pulp core layer.

6. The thin adult diaper according to claim 1, characterized in that: The structure of the composite core is ≥3 layers, and the composite core is formed by alternating layers of a first material layer and SAP; the first material layer is any one of non-woven fabric, toilet paper or fiber web.

7. The thin adult diaper according to claim 1, characterized in that: The composite core has a grammage of 80 gsm-600 gsm.

8. The thin adult diaper according to claim 1, characterized in that: The surface of the surface layer is provided with a guide groove.

9. A method for preparing thin adult diapers, characterized in that: The following steps are involved: S1. Preparation of a fluff pulp core layer: crushing the fluff pulp and uniformly mixing the fluff pulp and SAP polymer material in a weight ratio of (0.5-8): (2-9.5) to form a mixed slurry, and negatively adsorbing the mixed slurry into a first forming die wheel. The first forming die wheel is provided with a baffle to control the middle core absorption zone from falling out of the mixed slurry. After forming, demolding is performed to obtain a fluff pulp core layer with a groove; S2. Preparation of a composite core layer: The composite core layer is prepared in a second molding die wheel. A pressure-dividing zone is provided in the mold cavity of the second molding die wheel. The pressure-dividing zone includes a first pressure zone, a second pressure zone, and a third pressure zone. The negative pressure strength of the first pressure zone is adjusted to be ≥30% greater than the negative pressure strength of the third pressure zone. The SAP polymer material is adsorbed in the pressure-dividing zone. The non-woven fabric layer is unwound and conveyed. The SAP polymer material is spread online at a fixed point on the surface of the non-woven fabric layer. A non-woven fabric layer is then laminated online. The composite core layer is subjected to a pressure roller lamination process to obtain a non-woven fabric layer-SAP layer-non-woven fabric layer structure from top to bottom. S3. Compounding: The composite core layer obtained in step S2 is transferred online and filled into the groove of the fluff pulp core layer obtained in step S1 to obtain an absorbent core layer. The surface layer, the absorbent core layer and the liquid-impermeable bottom layer are compounded into one to obtain the thin adult diaper.

10. The method for preparing a thin adult diaper according to claim 9, characterized in that: The following steps are involved: I. Preparation of a fluff pulp core layer: crushing the fluff pulp and uniformly mixing the fluff pulp and SAP polymer material in a weight ratio of (0.5-8): (2-9.5) to form a mixed slurry, and negatively adsorbing the mixed slurry into a first forming die wheel. The first forming die wheel is provided with a baffle to control the middle core absorption zone from falling out of the mixed slurry. After forming, demolding is performed to obtain a fluff pulp core layer with a groove; II. Preparation of a semi-finished composite core layer: The semi-finished composite core layer is prepared in a second forming die wheel. A pressure-dividing zone is provided in the die cavity of the second forming die wheel. The pressure-dividing zone includes a first air pressure zone, a second air pressure zone, and a third air pressure zone. The negative pressure intensity of the first air pressure zone is adjusted to be ≥30% higher than the negative pressure intensity of the third air pressure zone. The SAP polymer material is adsorbed in the pressure-dividing zone, the non-woven fabric layer is unwound and conveyed, the SAP polymer material is spread online at a fixed point on the surface of the non-woven fabric layer, and then a non-woven fabric layer is composited online. The non-woven fabric layer is subjected to a pressure roller lamination process to obtain a semi-finished composite core layer having a structure of non-woven fabric layer-SAP layer-non-woven fabric layer from top to bottom; III. Preparation of the composite core layer: Adsorbing the SAP polymer material in another second forming die wheel, adjusting the negative pressure intensity of the first air pressure zone to be ≥30% greater than the negative pressure intensity of the third air pressure zone, unwinding and conveying the non-woven fabric layer, and spreading the SAP polymer material on the surface of the non-woven fabric layer at a fixed point online to obtain a non-woven fabric layer with the SAP polymer material spread on the surface, which is then composited with the semi-finished composite core layer to obtain a composite core layer consisting of non-woven fabric layer-SAP layer-non-woven fabric layer-SAP layer-non-woven fabric layer from top to bottom; IV. Compounding: The composite core layer prepared in step III is transferred online and filled into the groove of the fluff pulp core layer prepared in step I to obtain an absorbent core layer. The surface layer, the absorbent core layer and the liquid-impermeable bottom layer are compounded into one to obtain the thin adult diaper.

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