Online core and process for making same, disposable absorbent article employing online core

Abstract

The present application relates to the technical field of disposable absorbent articles, and proposes an online core and a manufacturing process thereof, and a disposable absorbent article adopting the online core, to solve the problems of waste of SAP material at both ends of an absorbent core, large amount of glue applied to the absorbent core affecting absorption, and high cost of non-online core use; the manufacturing process of the online core comprises laying of upper and lower SAP layers, compounding of a cladding layer and a lower absorbent layer, and compounding of upper and lower absorbent layers and fluffy cotton; the structure of the online core adopts a six-layer structure, and the disposable absorbent article adopting the online core is manufactured.

Description

Technical Field

[0001] This invention relates to the field of disposable absorbent materials, and particularly to an online core and its manufacturing process, and disposable absorbent materials using an online core. Background Technology

[0002] Firstly, in the current production and use chain of diapers and pull-ups, the absorbent core, as a core functional component, generally adopts the traditional model of "pre-made finished products + subsequent circulation." This model has generated many pain points in terms of cost and efficiency during actual operation, seriously restricting the industry's cost reduction, efficiency improvement, and experience optimization. After the finished absorbent core is manufactured in the factory, it is not directly used in the final assembly of diapers and pull-ups. Instead, it needs to go through three core intermediate links: packaging, transportation, and sterilization. This consumes a lot of financial resources (packaging materials, logistics costs, warehousing costs, sterilization equipment and consumables costs, etc.) and occupies too much manpower and time (packaging labor, warehousing management labor, sterilization operation labor, and process time consumption), resulting in high overall usage costs of the core and reducing the overall efficiency of production and use.

[0003] Secondly, in the current manufacturing process of absorbent cores, a hot melt adhesive layer is sprayed onto the intermediate layer before it enters the negative pressure adsorption mold wheel. The initial intention is to pre-form bonding points on the surface of the intermediate layer with the adhesive, providing a foundation for subsequent SAP adhesion. However, this step is fundamentally contradictory to the process characteristics of the "negative pressure adsorption mold wheel": hot melt adhesive needs to maintain high viscosity in a molten state (usually at a temperature of 120-160℃) to form an effective bond with the fiber layer and SAP. Once cooled to room temperature (or close to room temperature), its molecular activity decreases, and its viscosity drops significantly (some types of hot melt adhesives even become brittle after cooling). Negative pressure adsorption uses the negative pressure cavity inside the mold wheel to tightly adsorb the intermediate layer containing the hot melt adhesive layer onto the surface of the mold wheel, thereby fixing the intermediate layer and preventing subsequent SAP adhesion. During application, fibers shift; the negative pressure adsorption process accelerates the cooling of the hot melt adhesive layer. When the molten hot melt adhesive layer comes into contact with the surface of the low-temperature mold wheel, the heat is quickly absorbed by the mold wheel, causing the adhesive layer temperature to drop sharply, directly reducing the viscosity and making it unable to effectively adhere to SAP. It also affects the air permeability and water absorption performance of the absorbent core.

[0004] Secondly, when urine enters the core, due to gravity, capillary action, and the guiding effect of the core fibers, it preferentially converges towards the middle of the core (corresponding to the groin area) and is quickly absorbed by the SAP. However, the front and rear ends of the core (corresponding to the waist and abdomen) are farther from the liquid inlet (groin area) and have a longer liquid penetration path, resulting in most of the liquid being absorbed by the central SAP before reaching the front and rear ends. This ultimately leads to a significant difference in utilization rate: "empty at the front and rear ends, full in the middle." The "maximum absorbency" labeled on diaper products is a theoretical value calculated based on the total SAP content of the core. While SAP is evenly distributed throughout the core, the actual effective absorbency is far lower than the labeled value because the SAP at the front and rear ends is not fully utilized. The unused SAP at the front and rear ends is essentially "ineffective material." The utilization rate of SAP at the front and rear ends of diapers is typically less than 30%, meaning that approximately 15%-20% of the SAP in each diaper is wasted due to ineffective utilization.

[0005] To address the aforementioned comprehensive issues, this paper proposes an online core and its manufacturing process, which solves the pain point of "finished product prefabrication + subsequent circulation"; eliminates the adhesive layer on the intermediate layer, reduces the amount of adhesive used, and improves the core's absorption effect; and rationally distributes SAP to improve material utilization and increase the effective absorption capacity and absorption effect of the core. Summary of the Invention

[0006] Therefore, in response to the above problems, this invention proposes an online core and its manufacturing process to solve the problems of wasted SAP material at both ends of the absorbent core, the problem of large amount of adhesive applied to the absorbent core affecting absorption, and the problem of high cost of using off-line cores, as well as disposable absorbent articles using online cores.

[0007] To solve the above-mentioned technical problems, the solution adopted by the present invention is: an online core fabrication process, characterized by including the following steps: Step 1: The fluffy cotton is the middle layer of the absorbent core. The lower surface of the fluffy cotton is wrapped around several first templates of the first negative pressure adsorption mold wheel with the lower surface facing outward. A first SAP feeding bin is set above the first negative pressure adsorption mold wheel. The lower surface of the fluffy cotton is not sprayed with an adhesive layer. The SAP is evenly filled into the fiber gaps of the lower surface of the fluffy cotton to form a lower SAP layer by using the cooperation of negative pressure adsorption and the first templates. An anti-detachment interlayer is wrapped between the upper surface of the fluffy cotton and the first templates to prevent the SAP from penetrating and detaching from the fluffy cotton during the negative pressure adsorption process and before the fluffy cotton detaches from the first negative pressure adsorption mold wheel and enters the second negative pressure adsorption mold wheel. Step 2: A thin adhesive layer is sprayed onto the bonding surface of the lower absorbent layer, with an adhesive amount of 1.3g / ㎡-2.5g / ㎡. The adhesive adheres immediately to the lower surface of the fluffy cotton after it receives the SAP and leaves the feeding hopper, restricting the SAP from rolling off and shifting. The fluffy cotton and the lower SAP layer are separated from the first negative pressure adsorption mold wheel and conveyed to the second negative pressure adsorption mold wheel under the clamping of the lower absorbent layer and the anti-detachment interlayer. Step 3: The anti-detachment interlayer, lower SAP layer, fluffy cotton, and lower absorbent layer are wound around several second templates of the second negative pressure adsorption mold wheel under the action of the first bonding roller, with the lower absorbent layer facing inward and the anti-detachment interlayer facing outward. A second bonding roller and a separation roller are set behind the first bonding roller. The second bonding roller is bonded to the surface of the second negative pressure adsorption mold wheel, and the separation roller is away from the second negative pressure adsorption mold wheel. The anti-detachment interlayer is wound around the first bonding roller, the second bonding roller, and the separation roller in sequence. A negative pressure adsorption section for the anti-detachment interlayer is formed between the first bonding roller and the second bonding roller. The SAP remaining on the anti-detachment interlayer first enters the fluffy cotton through negative pressure adsorption, and then the anti-detachment interlayer separates from the fluffy cotton, exposing the upper surface of the fluffy cotton to the outside. Step 4: A second SAP feeding bin is set above the second negative pressure adsorption mold wheel. The upper surface of the fluffy cotton is not coated with adhesive. The SAP is positioned and filled into the fiber gaps on the upper surface of the fluffy cotton by the cooperation of negative pressure adsorption and the second template to form an upper SAP layer. The distribution of the upper SAP layer is less or none at the front and rear ends and more in the middle section. Step 5: The coating layer is first coated with a thin layer of adhesive and then laminated with the upper absorbent layer. The amount of adhesive sprayed is 1g / ㎡-1.5g / ㎡. The upper absorbent layer is then coated with a thin layer of adhesive. The amount of adhesive sprayed is 1.3g / ㎡-2.5g / ㎡. The coating layer, along with the upper absorbent layer, adheres to the upper surface of the fluffy cotton immediately after the fluffy cotton receives the SAP and detaches from the feeding hopper, thus restricting the SAP from rolling off and shifting. The width of the coating layer is greater than that of the fluffy cotton and it is located on the outermost layer. After the fluffy cotton detaches from the second negative pressure adsorption mold wheel, the coating layer catches the SAP that falls from the side of the fluffy cotton. Step 6: Spray a thin adhesive layer on both sides of the lower absorbent layer. Under the action of the flipping plate, the two sides of the coating layer are attached to the lower absorbent layer to form an online core. The online core is then immediately cut and transported to the disposable absorbent product manufacturing line to be laminated with the bottom and top layers.

[0008] A further improvement is made in step 4, where the second template is uniformly provided with adsorption ports. The diameter of the adsorption ports at the front and rear ends of the second template is smaller than that at the middle section of the second template. The length of the small-diameter adsorption port at the front end of the second template is 20mm-50mm, and the length of the small-diameter adsorption port at the rear end of the second template is 50mm-120mm. The amount of the upper SAP layer is less at the front and rear ends and more in the middle section.

[0009] A further improvement is made in step 4, where the second template has uniformly opened adsorption ports in the middle section, the length of the second template without adsorption ports at the front end is 20mm-50mm, the length of the second template without adsorption ports at the rear end is 50mm-120mm, and the distribution of the upper SAP layer is such that there are none at the front and rear ends and more in the middle section.

[0010] A further improvement is that the first template and / or the second template have an unopened section at the center line of symmetry in the left and right directions. The unopened section forms a SAP-free section at the center of the single-piece online core. The width of the SAP-free section in the left and right directions is 5mm-25mm, and the length in the front and back directions is 50mm-the length of the single-piece core. The SAP-free section is provided with a flow guide groove.

[0011] A further improvement is that the anti-detachment interlayer is integrally connected to the input end of the anti-detachment interlayer after passing around the separation roller, or the anti-detachment interlayer is integrally connected to the input end of the covering layer after passing around the separation roller.

[0012] The online core includes, from top to bottom, a covering layer, an upper absorbent layer, an upper SAP layer, a fluffy cotton layer, a lower SAP layer, and a lower absorbent layer. The two sides of the covering layer are adhered to the bottom surface of the lower absorbent layer. The upper SAP layer fills the upper end of the fluffy cotton layer, and the lower SAP layer fills the lower end of the fluffy cotton layer. The upper SAP layer is distributed with less or none at the front and rear ends and more in the middle section. The length of the section with less or no SAP at the front end is 20mm-50mm, and the length of the section with less or no SAP at the rear end is 30mm-120mm.

[0013] A further improvement is that the online core center is provided with a no-SAP section, the width of the no-SAP section in the left-right direction is 5mm-25mm, the length in the front-back direction is 50mm-the total length of a single core, and a guide groove is provided on the no-SAP section.

[0014] A further improvement is that the guide groove extends through the upper and lower surfaces of the online core.

[0015] A further improvement is that the coating layer is a hydrophilic nonwoven fabric layer; and the upper and lower absorbent layers are hydrophilic absorbent materials.

[0016] A disposable absorbent item, characterized in that: it comprises an absorbent item body, wherein the absorbent item body adopts the above-mentioned online core; the absorbent item body is a pull-up diaper, a diaper, a T-shaped diaper, a two-piece diaper, or a three-piece diaper.

[0017] By adopting the aforementioned technical solution, the beneficial effects of the present invention are: 1. The online core manufacturing model optimizes the entire core production, distribution, and usage chain, significantly reducing usage costs and improving production and usage efficiency. On the one hand, it reduces the use of packaging materials, aligning with the industry trend of green and environmentally friendly development and contributing to environmental protection; on the other hand, the simplified process greatly shortens the production cycle, improves overall production efficiency, better copes with fluctuations in market demand, and reduces the risk of inventory backlog.

[0018] Adopting the "online core" model, which enables "make-to-use" cores, fundamentally breaks through the pain points of the traditional model, achieving significant savings in financial and material resources. From a process optimization perspective, the online core model eliminates the separate packaging step for finished cores. After the cores are manufactured on the production line, they directly enter the subsequent assembly process of diapers and pull-ups, requiring no additional packaging materials or operations. This alone saves substantial packaging and labor costs. Simultaneously, since the cores do not need to be transported across stages or regions, warehousing is also eliminated, avoiding not only logistics costs, spoilage costs, and warehousing management expenses during transportation, but also reducing the risk of core performance degradation due to transportation and warehousing. In the sterilization stage, the "make-to-use" nature of online cores eliminates the need for complex unpacking and sterilization procedures. After being manufactured on a sterile production line, the cores are immediately integrated into the subsequent production process, remaining in a controlled sterile environment throughout, eliminating the risk of contamination at the source and saving on sterilization consumables and the labor and time costs associated with sterilization operations.

[0019] 2. The online core manufacturing process eliminates the hot melt adhesive layer before negative pressure on the middle layer (i.e., fluffy cotton). The SAP is fixed by "fluffy cotton fiber gaps + negative pressure adsorption". The SAP is distributed in two layers on the upper and lower surfaces of the fluffy cotton, making full use of the fiber gaps of the fluffy cotton, reducing the overall amount of adhesive used in the core, making the core softer, and improving the breathability and water absorption rate of the core. This helps to reduce moisture accumulation, improve comfort, and effectively reduce the incidence of diaper rash.

[0020] The three-dimensional mesh fiber structure of fluffy cotton inherently possesses "encapsulation" properties. Combined with the "compacting and positioning" of negative pressure adsorption, it can stably embed SAP particles within the fiber gaps (rather than the "surface stacking" of the original process). Even during core conveying and pressing processes, the SAP is not easily displaced. The natural fiber gaps of fluffy cotton form "open liquid absorption channels," allowing liquids to directly and quickly penetrate and diffuse to the surface of the SAP particles without needing to overcome the adhesive layer barrier. Without hot melt adhesive encapsulation, the SAP can freely expand after absorbing water, increasing the liquid absorption speed. The "make-to-use" characteristic of the online core avoids delamination problems that may occur during transportation and storage, thus further reducing the amount of adhesive applied to the upper and lower absorbent layers.

[0021] 3. Traditional diapers, due to the uniform distribution of SAP (Solid Absorbent Polymer) in the core, cause liquid to preferentially accumulate in the middle of the core (the crotch area) after entering. The SAP at the front and rear ends become "ineffective materials" because the liquid penetration path is long and they do not come into contact with sufficient liquid, resulting in a utilization rate of less than 30%. However, through the combined design of negative pressure adsorption and template, precise control of SAP distribution can be achieved: whether it is a gradient distribution of "less at the front and rear ends and more in the middle" or a concentrated distribution of "none at the front and rear ends and more in the middle," the SAP can accurately match the core area where liquid gathers. This targeted adsorption method ensures that the middle SAP is fully filled to catch the majority of urine, avoiding the waste of front and rear SAP in traditional designs. This allows the actual effective liquid absorption capacity of the core to be much closer to the theoretical value, significantly improving the liquid absorption performance and reliability of the diaper.

[0022] Furthermore, in this case, the SAP is filled in two layers on the upper and lower surfaces of the fluffy cotton. The lower SAP layer is evenly distributed to ensure that the absorbent core can fully absorb urine, while the upper SAP layer is precisely positioned and distributed, which is conducive to accurately matching the upper SAP layer to the core area where the liquid gathers. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the online core fabrication process according to an embodiment of the present invention.

[0024] Figure 2 yes Figure 1 Enlarged view of the local structure at point A in the middle.

[0025] Figure 3 yes Figure 1 Enlarged view of the local structure at point B.

[0026] Figure 4 yes Figure 1 Enlarged view of the local structure at point C.

[0027] Figure 5 yes Figure 1 Enlarged view of the local structure at point D.

[0028] Figure 6 This is a schematic diagram of the structure of the online core in an embodiment of the present invention.

[0029] Figure 7 This is a schematic diagram of the structure of the first template in an embodiment of the present invention.

[0030] Figure 8 This is a schematic diagram of the structure of the second template embodiment 1 in this invention.

[0031] Figure 9 This is a schematic diagram of the structure of the second template embodiment 2 in this invention.

[0032] Reference numerals: Covering layer 10, Upper absorbent layer 11, Online core 12, Fluffy cotton 13, Lower absorbent layer 15, First negative pressure adsorption mold wheel 16, First template 17, First SAP feeding bin 18, Anti-detachment interlayer 19, First bonding roller 20, Second negative pressure adsorption mold wheel 21, Second template 22, Second bonding roller 23, Separation roller 24, Anti-detachment interlayer negative pressure adsorption section 25, Second SAP feeding bin 26, Unopened section 27, No SAP section 28, Guide channel 29. Detailed Implementation

[0033] The present invention will now be further described in conjunction with the accompanying drawings and specific embodiments.

[0034] refer to Figures 1 to 9 The embodiments of the present invention disclose an online core and its manufacturing process, and an online core manufacturing process for disposable absorbent articles using an online core.

[0035] A disposable absorbent item includes an absorbent item body, wherein the absorbent item body adopts an online core 12, and the absorbent item body is a pull-up diaper, a diaper, a T-shaped diaper, a two-piece diaper, or a three-piece diaper.

[0036] The aforementioned online core 12 includes, from top to bottom, a covering layer 10, an upper absorbent layer 11, an upper SAP layer, a fluffy cotton 13, a lower SAP layer, and a lower absorbent layer 15. The covering layer 10 is a hydrophilic nonwoven fabric layer; the upper absorbent layer 11 and the lower absorbent layer 15 are hydrophilic absorbent materials, specifically expanded paper, spunbond fabric, hot-air fabric, or spunlace fabric. The two sides of the covering layer 10 are adhered to the bottom surface of the lower absorbent layer 15. The upper SAP layer fills the upper end of the fluffy cotton 13, and the lower SAP layer fills the lower end of the fluffy cotton. The upper SAP layer is distributed with fewer or none at the front and rear ends and more in the middle section. The length of the section 28 with fewer or no SAP at the front end of the upper SAP layer is 20mm-50mm, preferably 40mm; the length of the section 28 with fewer or no SAP at the rear end of the upper SAP layer is 30mm-120mm, preferably 80mm.

[0037] Furthermore, the online core 12 has a SAP-free section 28 at its center. The SAP-free section 28 has a width of 5mm-25mm in the left-right direction and a length of 50mm-the total length of a single core in the front-back direction. Preferably, it has a width of 10mm and a length of 100mm. A flow guide groove 29 is provided on the SAP-free section 28, and the length and width of the flow guide groove 29 do not exceed the length and width of the SAP-free section 28.

[0038] Furthermore, the flow channel 29 extends through the upper and lower surfaces of the online core 12.

[0039] The above-mentioned online absorption core manufacturing process includes the following steps: Step 1: The fluffy cotton 13 serves as the middle layer of the absorbent core. Before being fed into the first negative pressure adsorption roller 16, the fluffy cotton 13 undergoes a pre-stretching treatment to increase the fiber gaps. The pre-stretching ratio is 1.2 times, which facilitates deeper penetration of the SAP into the fluffy cotton 13, enhancing its SAP adhesion performance. The circumferential adsorption surface of the first negative pressure adsorption roller 16 is formed by several first templates 17 spliced ​​together end to end. The lower surface of the fluffy cotton 13 is wrapped around the first template 17 of the first negative pressure adsorption mold wheel 16 with its lower surface facing outward. A first SAP feeding bin 18 is provided above the first negative pressure adsorption mold wheel 16. The lower surface of the fluffy cotton 13 is not coated with an adhesive layer. The SAP is evenly filled into the fiber gaps of the lower surface of the fluffy cotton 13 by the cooperation of negative pressure adsorption and the first template 17 to form a lower SAP layer. An anti-detachment interlayer 19 is wrapped between the upper surface of the fluffy cotton 13 and the first template 17 to prevent the SAP from penetrating and detaching from the fluffy cotton 13 during the negative pressure adsorption process and before the fluffy cotton 13 detaches from the first negative pressure adsorption mold wheel and enters the second negative pressure adsorption mold wheel. Step 2: Since no adhesive is applied to the fluffy cotton 13, the lower absorbent layer 15 needs to be laminated immediately after it leaves the first SAP feeding hopper 18. A thin adhesive layer is sprayed onto the bonding surface of the lower absorbent layer 15, with an adhesive amount of 1.3g / ㎡-2.5g / ㎡, preferably 2.0g / ㎡; immediately after the fluffy cotton 13 receives the SAP and leaves the feeding hopper, it adheres to the lower surface of the fluffy cotton 13 to restrict the SAP from rolling off and shifting; the fluffy cotton 13 and the lower SAP layer are separated from the first negative pressure adsorption mold wheel 16 and conveyed to the second negative pressure adsorption mold wheel 21 under the clamping of the lower absorbent layer 15 and the anti-detachment interlayer 19; Step 3: The anti-detachment interlayer 19, lower SAP layer, fluffy cotton 13, and lower absorbent layer 15 are wound around the second template 22 of the second negative pressure adsorption mold wheel 21 under the action of the first bonding roller 20. The lower absorbent layer 15 faces inward and the anti-detachment interlayer 19 faces outward. A second bonding roller 23 and a separation roller 24 are arranged behind the first bonding roller 20. The second bonding roller 23 is bonded to the surface of the second negative pressure adsorption mold wheel 21, and the separation roller 24 is away from the second negative pressure adsorption mold wheel 21. The anti-detachment interlayer 19 is wound around the first bonding roller 20, the second bonding roller 23, and the separation roller 24 in sequence. An anti-detachment interlayer negative pressure adsorption section 25 is formed between the first bonding roller 20 and the second bonding roller 23. The SAP remaining on the anti-detachment interlayer 19 first enters the fluffy cotton 13 through negative pressure adsorption. Then the anti-detachment interlayer 19 separates from the fluffy cotton 13, and the upper surface of the fluffy cotton is exposed outward. Step 4: A second SAP feeding bin 26 is set above the second negative pressure adsorption mold wheel 21. The upper surface of the fluffy cotton 13 is not coated with adhesive. The SAP is positioned and filled into the fiber gaps on the upper surface of the fluffy cotton 13 by the cooperation of negative pressure adsorption and the second template 22 to form an upper SAP layer. The distribution of the upper SAP layer is less or none at the front and rear ends and more in the middle section. Step 5: Since no adhesive was applied to the fluffy cotton 13, the upper absorbent layer 11 needs to be laminated immediately after it leaves the second SAP feeding hopper 26. The coating layer 10 is sprayed with a thin adhesive layer, with an adhesive amount of 1g / ㎡-1.5g / ㎡, preferably 1.1g / ㎡. The coating layer 10 is first laminated with the upper absorbent layer 11, and the upper absorbent layer 11 is sprayed with a thin adhesive layer, with an adhesive amount of 1.3g / ㎡-2.5g / ㎡, preferably 2.0g / ㎡. The coating layer 10, along with the upper absorbent layer 11, adheres to the upper surface of the fluffy cotton 13 immediately after it receives the SAP and leaves the feeding hopper, restricting the SAP from rolling off and shifting. The width of the coating layer 10 is greater than that of the fluffy cotton 13 and it is located on the outermost layer. After the fluffy cotton 13 leaves the second negative pressure adsorption roller 21, the coating layer 10 catches the SAP falling from the side of the fluffy cotton 13. Step 6: A thin adhesive layer is sprayed on both sides of the lower absorbent layer 15. The two sides of the covering layer 10 are attached to the lower absorbent layer 15 under the action of the flip plate to form the online core 12. The online core 12 is immediately cut and then transported to the disposable absorbent product manufacturing line to be laminated with the bottom layer and the top layer.

[0040] Furthermore, the second template embodiment 1 (see Figure 8 In step 4, the second template 22 is uniformly provided with adsorption ports for adsorbing the fluffy cotton 13 and SAP. The diameter of the adsorption ports at the front and rear ends of the second template 22 is smaller than the diameter of the port in the middle section of the second template. The length of the small-diameter adsorption port at the front end of the second template 22 is 20mm-50mm, preferably 40mm, and the length of the small-diameter adsorption port at the rear end of the second template 22 is 50mm-120mm, preferably 80mm. The amount of the upper SAP layer is less at the front and rear ends and more in the middle section. The length of the less SAP layer at the front end is 20mm-50mm, preferably 40mm, and the length of the less SAP layer at the rear end is 30mm-120mm, preferably 80mm.

[0041] Second template example 2 (see Figure 9 In step 4, the second template 22 has uniformly distributed adsorption ports in its middle section for adsorbing the fluffy cotton 13 and SAP. The length of the front end of the second template 22 without adsorption ports is 20mm-50mm, preferably 40mm, and the length of the rear end of the second template 22 without adsorption ports is 50mm-120mm, preferably 80mm. The upper SAP layer is distributed with none at both ends and more in the middle. The length of the upper SAP layer without SAP at the front end is 20mm-50mm, preferably 40mm, and the length of the upper SAP layer without SAP at the rear end is 30mm-120mm, preferably 80mm.

[0042] Furthermore, the first template and / or the second template are provided with an unopened section 27 at the symmetrical center line in the left-right direction. The unopened section 27 forms a SAP-free section 28 at the center of the monolithic online core 12. The SAP-free section 28 has a width of 5mm-25mm in the left-right direction and a length of 50mm to the total length of the monolithic core in the front-back direction. The SAP-free section 28 is provided with a guide groove 29. Preferably, it has a width of 10mm and a length of 100mm.

[0043] Furthermore, the anti-detachment interlayer 19 is integrally connected to the input end of the anti-detachment interlayer after passing around the separation roller 24, that is, the anti-detachment interlayer 19 can be made of breathable non-woven fabric or a conveyor belt connected end to end for individual driving and repeated use.

[0044] Alternatively, the anti-detachment interlayer 19 may be integrally connected to the input end of the covering layer 10 after passing around the separating roller 24. That is, the same material layer is used as the anti-detachment interlayer 19 in the early stage of the manufacturing process and as the covering layer 10 in the later stage. The covering layer 10 is a hydrophilic nonwoven fabric.

[0045] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions above are merely illustrative of the principles of the present invention. Various changes and modifications can be made to the present invention without departing from its spirit and scope. All such changes and modifications fall within the scope of the present invention as claimed, which is defined by the appended claims and their equivalents.

Claims

1. An online core manufacturing process, characterized by: Includes the following steps: Step 1: The fluffy cotton is the middle layer of the absorbent core. The lower surface of the fluffy cotton is wrapped around several first templates of the first negative pressure adsorption mold wheel with the lower surface facing outward. A first SAP feeding bin is set above the first negative pressure adsorption mold wheel. The lower surface of the fluffy cotton is not sprayed with an adhesive layer. The SAP is evenly filled into the fiber gaps of the lower surface of the fluffy cotton to form a lower SAP layer by using the cooperation of negative pressure adsorption and the first templates. An anti-detachment interlayer is wrapped between the upper surface of the fluffy cotton and the first templates to prevent the SAP from penetrating and detaching from the fluffy cotton during the negative pressure adsorption process and before the fluffy cotton detaches from the first negative pressure adsorption mold wheel and enters the second negative pressure adsorption mold wheel. Step 2: A thin adhesive layer is sprayed onto the bonding surface of the lower absorbent layer, with an adhesive amount of 1.3g / ㎡-2.5g / ㎡. The adhesive adheres immediately to the lower surface of the fluffy cotton after it receives the SAP and leaves the feeding hopper, restricting the SAP from rolling off and shifting. The fluffy cotton and the lower SAP layer are separated from the first negative pressure adsorption mold wheel and conveyed to the second negative pressure adsorption mold wheel under the clamping of the lower absorbent layer and the anti-detachment interlayer. Step 3: Under the action of the first bonding roller, the anti-detachment interlayer, the lower SAP layer, the fluffy cotton, and the lower absorbent layer are wound around several second templates of the second negative pressure adsorption mold wheel with the lower absorbent layer facing inward and the anti-detachment interlayer facing outward. A second bonding roller and a separation roller are arranged behind the first bonding roller. The second bonding roller is attached to the surface of the second negative pressure adsorption mold wheel, and the separation roller is away from the second negative pressure adsorption mold wheel. The anti-detachment interlayer is wound around the first bonding roller, the second bonding roller, and the separation roller in sequence. A negative pressure adsorption section for the anti-detachment interlayer is formed between the first bonding roller and the second bonding roller. The SAP remaining on the anti-detachment interlayer first enters the fluffy cotton through negative pressure adsorption, and then the anti-detachment interlayer separates from the fluffy cotton, exposing the upper surface of the fluffy cotton to the outside. The anti-detachment interlayer becomes a covering layer after passing around the separation roller. Step 4: A second SAP feeding bin is set above the second negative pressure adsorption mold wheel. The upper surface of the fluffy cotton is not coated with adhesive. The SAP is positioned and filled into the fiber gaps on the upper surface of the fluffy cotton by the cooperation of negative pressure adsorption and the second template to form an upper SAP layer. The distribution of the upper SAP layer is less or none at the front and rear ends and more in the middle section. Step 5: The coating layer is first coated with a thin adhesive layer and then laminated with the upper absorbent layer. The amount of adhesive sprayed is 1g / ㎡-1.5g / ㎡. The upper absorbent layer is then coated with a thin adhesive layer. The amount of adhesive sprayed is 1.3g / ㎡-2.5g / ㎡. The coating layer, along with the upper absorbent layer, adheres to the upper surface of the fluffy cotton immediately after it receives the SAP and detaches from the feeding hopper, thus restricting the SAP from rolling off and shifting. The width of the coating layer is greater than that of the fluffy cotton and it is located on the outermost layer. After the fluffy cotton detaches from the second negative pressure adsorption mold wheel, the coating layer receives the SAP that falls from the side of the fluffy cotton. Step 6: Spray a thin adhesive layer on both sides of the lower absorbent layer. Under the action of the flipping plate, the two sides of the coating layer are attached to the lower absorbent layer to form an online core. The online core is then immediately cut and transported to the disposable absorbent product manufacturing line to be laminated with the bottom and top layers.

2. The online core fabrication process according to claim 1, characterized in that: In step 4, the second template is uniformly provided with adsorption ports. The diameter of the adsorption ports at the front and rear ends of the second template is smaller than the diameter of the adsorption ports in the middle section of the second template. The length of the small-diameter adsorption ports at the front end of the second template is 20mm-50mm, and the length of the small-diameter adsorption ports at the rear end of the second template is 50mm-120mm. The amount of the upper SAP layer is less at the front and rear ends and more in the middle section.

3. The online core fabrication process according to claim 1, characterized in that: In step 4, the second template has uniformly opened adsorption ports in the middle section. The length of the second template without adsorption ports at the front end is 20mm-50mm, and the length of the second template without adsorption ports at the rear end is 50mm-120mm. The distribution of the upper SAP layer is that there are none at the front and rear ends, and more in the middle section.

4. The online core fabrication process according to claim 1, 2, or 3, characterized in that: The first template and / or the second template are provided with an unopened section at the center line of symmetry in the left and right directions. The unopened section forms a SAP-free section at the center of the single-piece online core. The width of the SAP-free section in the left and right directions is 5mm-25mm, and the length in the front and back directions is 50mm-the total length of the single-piece core. The SAP-free section is provided with a flow guide groove.

5. The online core manufactured according to any one of the manufacturing processes described in claims 1-4, characterized in that: It includes, from top to bottom, a covering layer, an upper absorbent layer, an upper SAP layer, a fluffy cotton, a lower SAP layer, and a lower absorbent layer. The two sides of the covering layer are adhered to the bottom surface of the lower absorbent layer. The upper SAP layer fills the upper end of the fluffy cotton, and the lower SAP layer fills the lower end of the fluffy cotton. The online core has a SAP-free section at its center. The SAP-free section has a width of 5mm-25mm in the left-right direction and a length of 50mm-the total length of a single core in the front-back direction. The SAP-free section has a flow guide groove that runs through the upper and lower surfaces of the online core.

6. The online core according to claim 5, characterized in that: The covering layer is a hydrophilic nonwoven fabric layer; the upper absorbent layer and the lower absorbent layer are hydrophilic absorbent materials.

7. A disposable absorbent material, characterized in that: It includes an absorbent material body, wherein the absorbent material body adopts the online core as described in claim 5 or 6 above; the absorbent material body is a pull-up diaper or a disposable diaper.

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