Patterned Fibrous Structure for Flexibility and Strength
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Solution Overview
Problem
Existing fibrous structures face a challenge in enhancing flexibility without compromising strength, as methods to increase one property often adversely affect the other, leading to consumer-unacceptable results in products like sanitary tissue products.
Innovation Solution
A fibrous structure comprising a plurality of first and second line elements, where the ratio of the average distance between the second line elements to the first line elements is greater than 1, is developed, along with a method involving depositing a fibrous slurry onto a forming wire and transferring it to a molding member to form a patterned drying belt, allowing for increased flexibility and strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If steps are taken to increase the strength of a fibrous structure, then the strength is improved, but the flexibility, softness, or absorbency deteriorates
Solution Approach 1:
The patent applies local quality by creating distinct regions within the fibrous structure: bonded regions (providing strength) and unbonded regions (providing flexibility). The molded pattern creates localized areas of high fiber concentration that are bonded together, while leaving other areas unbonded. This spatial differentiation of bonding density allows the structure to exhibit both high tensile strength in bonded zones and flexibility in unbonded zones simultaneously.
Solution Approach 2:
The patent segments the fibrous structure into discrete molded patterns consisting of raised portions and recessed portions. These segmented regions are bonded to the support member in a non-uniform pattern, creating a mosaic of bonded and unbonded areas. This segmentation allows independent optimization of strength (in bonded regions) and flexibility (in unbonded regions) without compromising the overall structure.
2Ease of operation
If alternating continuous knuckles and continuous pillows are used to increase flexibility, then flexibility is improved, but tensile strength deteriorates
Solution Approach 1:
The patent breaks the continuous knuckle and pillow structure into segmented molded patterns with discrete raised and recessed portions. This segmentation creates isolated bonded regions rather than continuous bonded zones, allowing flexibility to be maintained while preventing the complete loss of tensile strength that occurs in continuous structures. The segmented approach distributes bonding stress across multiple discrete points.
Solution Approach 2:
The patent creates local quality variations by forming specific molded patterns with raised portions (higher fiber concentration) and recessed portions (lower fiber concentration) that are selectively bonded. This local differentiation allows certain areas to provide flexibility while others provide strength, resolving the contradiction between continuous flexibility-enhancing structures and overall tensile strength.
3Strength
If cellulosic fiber bonding within the product is increased to enhance strength, then strength is improved, but softness deteriorates
Solution Approach 1:
The patent applies local quality by creating heterogeneous bonding density across the fibrous structure. Areas with high cellulosic fiber bonding provide strength, while areas with low or no bonding maintain softness and comfort. The molded pattern creates this local quality variation systematically, with bonded regions providing structural integrity and unbonded regions providing softness and absorbency.
Solution Approach 2:
The patent segments the bonding distribution into discrete molded patterns rather than uniform bonding throughout. This segmentation allows strength-critical areas to have high bonding while comfort-critical areas have low bonding. The raised and recessed portions create natural zones of different bonding density, enabling simultaneous optimization of strength and softness.
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
The solution achieves consumer-acceptable flexibility and strength in fibrous structures, such as sanitary tissue products, by decoupling the properties of flexibility and strength, ensuring that increased flexibility does not negatively impact tensile strength.
Implementation Method 1
depositing a fibrous slurry onto a forming wire to form an embryonic web
Implementation Method 2
transferred the embryonic web to a molding member such that a surface comprising at least two first line elements extending in a first direction and at least two second line elements extending in a second direction different from the first direction
Implementation Method 3
drying the embryonic web such that a fibrous structure comprising a surface comprising at least two first line elements extending in a first direction and at least two second line elements extending in a second direction different from the first direction
Data Source
AI summary
Fibrous structures having a surface including a plurality of line elements and a method for making same is provided.