Absorbent Core Channel Formation Using Pneumatic Suction
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Solution Overview
Problem
Existing methods for making absorbent cores with channels suffer from absorbent material deposition on the insert surface, leading to dust accumulation and poor adhesion, resulting in variability in product performance and quality, especially upon wetting.
Innovation Solution
A method and apparatus using a rotating drum with molds having inserts in fluid communication with an under-pressure source, where a nonwoven web is fed over the molds, and an absorbent material is deposited and then removed from areas corresponding to the inserts using a suction zone and air cushion or pulsating airstream to prevent material deposition, ensuring channels are free of absorbent material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If absorbent material is deposited over the nonwoven web during manufacturing, then the absorbent core gains sufficient absorbent material for fluid absorption, but absorbent material accumulates on the insert surface leading to dust accumulation and poor adhesion
Solution Approach 1:
The patent applies pneumatic principles by using an under-pressure source (vacuum) applied to the insert to create a suction zone that prevents absorbent material from depositing on the insert surface during the deposition process. This pneumatic control enables precise channel formation by selectively controlling where material accumulates (on the nonwoven web) and where it is removed (from the insert surface), thereby resolving the contradiction between having sufficient absorbent material and achieving precise channel formation.
2Manufacturing precision
If additional mechanical removal steps are used to clear absorbent material from insert surfaces, then channel formation quality improves, but device complexity and manufacturing time increase
Solution Approach 1:
The patent implements preliminary action by applying the under-pressure source to the insert before absorbent material deposition occurs. This preventive measure ensures that material does not accumulate on the insert surface in the first place, eliminating the need for subsequent mechanical removal steps. The suction zone is established in advance to control material placement, thereby simplifying the overall manufacturing process while maintaining high channel formation precision.
3Reliability
If absorbent material accumulates on insert surfaces, then dust accumulation occurs and adhesion deteriorates, but removing material requires additional process steps
Solution Approach 1:
The patent uses pneumatic control through an under-pressure source applied to the insert to create a suction zone that prevents absorbent material accumulation during deposition. This approach maintains reliable product quality by ensuring consistent channel formation without material accumulation, while preserving manufacturing efficiency by eliminating the need for additional mechanical removal steps that would reduce productivity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach eliminates the need for additional mechanical removal steps, reduces variability, and enhances the wet integrity and quality of the absorbent core by preventing absorbent material from accumulating on the insert surfaces, thus improving product performance.
Implementation Method 1
molds are in fluid communication with an under-pressure source except for said insert such that a suction zone is formed in areas neighboring said insert
Implementation Method 2
at least a portion of said insert is porous and is in fluid communication with a positive pressure source such that air is blown out of said insert to form an air cushion or air film around at least an uppermost surface of said insert
Implementation Method 3
air is blown out and sucked-in of said insert in a substantially alternating manner to form a pulsating airstream substantially around at least an uppermost surface of said insert such that said absorbent material is forced away from areas of the nonwoven web corresponding to said insert
Data Source
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AI summary
A method for making an absorbent article comprising an absorbent core comprising one or more channels, the method comprising the steps of: i. providing a first endless moving surface comprising a plurality of molds typically in the form of pockets, each mold comprising an insert therein, wherein the molds are in fluid communication with an underpressure source except for said insert such that a suction zone is formed in areas neighboring said insert; ii. feeding a first nonwoven web to said first endless moving surface and over one or more said molds; iii. depositing an absorbent material, comprising cellulose fibers and/or superabsorbent polymer particles, over at least a portion of said nonwoven web; iv. optionally further selectively removing said absorbent material from areas of the nonwoven web corresponding to said insert; v. applying a second nonwoven web directly or indirectly over the absorbent material, or folding said first nonwoven web, such to sandwich said absorbent material between upper and lower layers of said nonwoven web(s); vi. joining said upper and lower layers together at least in the areas of the nonwoven web(s) corresponding to the insert to form an absorbent core having one or more channels substantially free of absorbent material; vii. optionally joining an acquisition distribution layer to said absorbent core, typically a skin facing surface of said upper layer; viii. optionally laminating said absorbent core and acquisition distribution layer between a liquid pervious topsheet and a liquid impervious backsheet; wherein at least a portion of said insert is porous and is in fluid communication with a positive pressure source such that air is blown out of said insert to form an air cushion or air film around at least an uppermost surface of said insert and in that said absorbent material is thereby forced away from areas of the nonwoven web corresponding to said insert.