Resilient Coform Nonwoven Web Using Propylene Copolymer
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional coform nonwoven webs lack resilience when subjected to bending forces, often failing to return to their original flat state after being folded or crumpled, which is a limitation in various applications such as absorbent products.
Innovation Solution
A resilient coform nonwoven web is developed, comprising a matrix of meltblown fibers formed from a thermoplastic composition with a propylene/α-olefin copolymer, which constitutes 45 wt% to 99 wt% of the web, and an absorbent material making up 1 wt% to 55 wt%, with specific properties that enhance thermal properties and adherence, allowing the web to retain and regain a three-dimensional shape.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If conventional polypropylene homopolymer meltblown fibers are used in coform nonwoven webs, then the web provides adequate absorbency and structure, but the web lacks resilience and cannot return to its original flat state after bending or crumpling
Solution Approach 1:
The patent changes the chemical composition parameters of the thermoplastic binder from conventional polypropylene homopolymer to a specific propylene/α-olefin copolymer with controlled density (0.86-0.90 g/cm³) and melt flow rate (200-6000 g/10 min). This parameter change enables the binder to provide both structural integrity and resilience, allowing the web to return to its original shape after bending while maintaining ease of manufacture through standard meltblown processes.
2Strength
If the melt flow rate of the thermoplastic composition is increased to improve fiber formation and web structure, then the web structure is enhanced, but the resilience and ability to return to flat state is reduced
Solution Approach 1:
The patent identifies and controls the melt flow rate parameter within an optimal range of 200-6000 g/10 min (preferably 170-1500 g/10 min) at 230°C. This parameter optimization ensures that the thermoplastic composition provides sufficient viscosity for proper fiber formation and web structure while maintaining enough flexibility and elasticity to enable resilience. The copolymer's molecular structure, with its specific density and melt flow characteristics, allows the material to form strong bonds during web formation yet remain resilient under bending forces.
3Quantity of substance
If the density of the copolymer is adjusted to optimize web density and absorbency, then absorbency is improved, but the resilience and texture retention is compromised
Solution Approach 1:
The patent optimizes the copolymer density parameter within the range of 0.86-0.90 g/cm³ (preferably 0.861-0.89 g/cm³, most preferably 0.862-0.88 g/cm³). This density range allows the thermoplastic binder to create a web structure with sufficient porosity and void space for enhanced absorbency while maintaining the structural integrity and elasticity needed for texture retention and resilience. The balanced density ensures the web can accommodate absorbent materials effectively without compromising its ability to return to its original shape.
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 web demonstrates improved resistance to bending forces and maintains its flat state after folding, offering enhanced ply attachment strength and texture retention, reducing the need for embossing and improving performance in absorbent applications.
Implementation Method 1
meltblown fibers formed from a thermoplastic composition
Implementation Method 2
The meltblown fibers are formed from a thermoplastic composition... wherein the composition has a melt flow rate
Data Source
AI summary
A resilient coform nonwoven web that contains a matrix of meltblown fibers and an absorbent material is provided. The meltblown fibers may constitute from 45 wt % to about 99 wt % of the web and the absorbent material may constitute from about 1 wt % to about 55 wt % of the web. The meltblown fibers may be formed from a thermoplastic composition that contains at least one propylene/α-olefin copolymer having a propylene content of from about 60 mole % to about 99.5 mole % and an α-olefin content of from about 0.5 mole % to about 40 mole %. The copolymer may have a density of from about 0.86 to about 0.90 grams per cubic centimeter and the thermoplastic composition may have a melt flow rate of from about 200 to about 6000 grams per 10 minutes, determined at 230° C. in accordance with ASTM Test Method D1238-E. The coform web may be imparted with a three-dimensional texture by, for example, using a three-dimensional forming surface. As one example, the resilient coform web is suitable for use as a component in the absorbent core of a personal care absorbent product.