Extensible Coform Absorbent Composites
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Solution Overview
Problem
Coform nonwoven composite materials used in absorbent applications tend to be stiff, which is exacerbated by heat embossing, and existing solutions like stretch-bonded laminates are costly due to high capital and elastomer costs.
Innovation Solution
A composite sheet material comprising a coform blend of absorbent fibers and meltblown fibers that can be permanently elongated through incremental stretching, combined with extensible thermoplastic fibers or filaments to create a soft, drapeable laminate with improved strength and absorbency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If heat embossing is applied to coform nonwoven composite materials, then bonding strength is improved, but stiffness increases and drapeability deteriorates
Solution Approach 1:
The patent changes the physical state and mechanical properties of the meltblown fibers through controlled thermal stretching and biaxial orientation processes. By adjusting stretching ratios, temperatures, and humidity conditions, the fibers transition from a stiff state to an extensible state with improved drapeability while maintaining bonding strength through controlled crystallinity changes
2Ease of operation
If stretch-bonded laminates are used to improve drapeability, then softness and drapeability are improved, but capital cost and elastomer cost increase significantly
Solution Approach 1:
The patent replaces expensive elastomeric components with disposable, thermoplastic meltblown fibers that can be thermally stretched and bonded. This substitution eliminates the need for costly elastomers and complex stretch-bonding equipment while achieving similar drapeability improvements through controlled thermal processing of the meltblown fiber matrix
Solution Approach 2:
The patent achieves the softening and drapeability improvement effect through controlled thermal stretching parameters applied to meltblown fibers, eliminating the need for expensive elastomeric materials. By adjusting stretching ratio, temperature, and humidity, the same functional effect is obtained at lower material and capital costs
3Strength
If adhesive emulsion is used to bond wood fibers in air laid process, then fiber bonding is improved, but stiffness increases due to adhesive presence
Solution Approach 1:
The patent extracts and eliminates the adhesive component from the fiber bonding system. Instead of using adhesive emulsion to bond wood fibers, the invention relies on mechanical interlocking through thermal stretching of meltblown fibers and direct fiber-to-fiber bonding, removing the source of stiffness while maintaining bonding strength
Solution Approach 2:
The patent replaces the chemical bonding mechanism (adhesive emulsion) with a mechanical bonding mechanism (thermal stretching and mechanical interlocking of fibers). This substitution eliminates the need for adhesives that cause stiffness while achieving adequate fiber bonding through physical interlocking of the stretched meltblown fiber network
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 results in a composite sheet material that is both soft and drapeable while maintaining strength and tear resistance, suitable for absorbent applications like wipes, with reduced material costs compared to traditional methods.
Implementation Method 1
Because the meltblown fibers are thermoplastic, they can be used to strengthen the air formed matrix by thermal bonding. Heat embossing coform webs is commonly practiced.
Implementation Method 2
After the bonding is complete, the tension on the elastic component is released, producing a soft, bulky stretch-bonded laminated fabric.
Implementation Method 3
non woven fibrous elastomeric materials with improved drapeability can be formed by hydraulically entangling a coform comprising an admixture of meltblown fibers and fibrous material
Data Source
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AI summary
Absorbent sheet materials are produced from a coformed blend of absorbent fibers and extensible meltblown polymer fibers. Laminates of these extensible coforms are prepared with layers of extensible polymeric fibers or filaments. The absorbent sheet materials are incrementally stretched to improve softness and drape.