Calendered Nonwoven Wipe Fabric for Strength and Water Dispersibility
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Solution Overview
Problem
Current nonwoven fabric materials for wet wipes face challenges in achieving a balance between biodegradability, water dispersibility, mechanical strength, and softness, particularly in maintaining strength in both machine and cross directions, while also providing an attractive appearance and being flushable.
Innovation Solution
The development of nonwoven fabric materials incorporating biodegradable long fibers or continuous filaments, such as polylactic acid (PLA), combined with water-absorbent materials like cellulose pulp, and a specific calendering pattern that balances tensile strength ratios and enhances water dispersibility, along with hydrophilic coatings and additives for improved absorption and softness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If cellulose-based raw materials (pulp, viscose, lyocell) are used to provide high absorbent properties, then the cloth can retain sufficient solution, but the stack becomes dense and height is reduced, giving a negative appearance
Solution Approach 1:
The patent uses composite nonwoven fabrics combining cellulose-based fibers (for absorbency) with thermoplastic fibers like polypropylene or polyester (for bulk and structure). This composite approach allows the fabric to maintain high solution retention while achieving sufficient stack height and a better appearance in flexible packaging.
2Shape
If thermoplastic materials (polypropylene, polyester) are added to provide bulk and softness, then the wipe appearance and feel improve, but biodegradability is compromised
Solution Approach 1:
The patent modifies the composition parameters by limiting thermoplastic content to specific ranges (5-50% polypropylene, 5-30% polyester) while maintaining sufficient bulk and softness. This parameter optimization allows the fabric to achieve desirable physical properties while improving biodegradability compared to conventional high-thermoplastic formulations.
3Stability of the object's composition
If biodegradable materials are used to fulfill environmental requirements, then the product can be flushable and biodegradable, but water dispersibility is reduced and may block pumps
Solution Approach 1:
The patent applies local quality differentiation by using primarily cellulose-based fibers (pulp, viscose, lyocell) which naturally possess good water dispersibility. This localized use of highly water-soluble materials in key areas of the fabric ensures rapid dispersion in water systems, preventing pump blockages while maintaining overall biodegradability.
4Strength
If mechanical strength is increased to prevent tearing during production and dispensing, then the wipe maintains integrity, but water dispersibility and biodegradability are compromised
Solution Approach 1:
The patent utilizes phase transition properties of thermoplastic fibers during the bonding process. The thermoplastic components melt and re-solidify to create strong bonds between cellulose fibers, providing necessary mechanical strength for production and dispensing. However, these same thermoplastic bonds are designed to break down under specific conditions, allowing water dispersibility and biodegradability to be maintained.
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 provides nonwoven fabrics with improved mechanical properties, balanced tensile strength in both directions, enhanced water dispersibility, and a soft, bulky appearance, making them suitable for flushable and biodegradable wet wipes that maintain strength even when wet.
Implementation Method 1
The nonwoven fabric is calendered to provide a calendered pattern having a strength in the machine direction and a strength in a cross direction perpendicular to the machine direction, wherein a ratio of the strength in the machine direction to the strength in the cross direction is in the range of from 1:1 to 4:1
Implementation Method 2
hydrophilic coatings and additives for improved absorption and softness
Implementation Method 3
nonwoven fabric materials that are biodegradable
Data Source
AI summary
Nonwoven calendered materials for various applications such as household use and personal and hygienic care are provided. In particular, the present invention can be applied to the manufacture of wipes and cleaning cloths. Methods for making and using nonwoven calendered fabrics are also provided.