Binderless Hydroentangled Airlaid Nonwoven Webs
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Solution Overview
Problem
Conventional methods for producing nonwoven webs for industrial wipes often result in products with poor wet strength, low abrasion resistance, and high lint or dust content, which are not economically efficient and require the use of non-biodegradable binders.
Innovation Solution
A continuous method involving the preparation of a mixture of defibrated natural cellulose fibers, bonding fibers, and optionally manmade fibers, airforming to create a homogeneous airlaid web, followed by hydroentangling and simultaneous drying and thermobonding, without the use of adhesives or binders, to produce a nonwoven web with enhanced wet strength and absorbency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional airlaid methods use latex binder compositions to obtain strength, then dry strength is improved, but wet strength and environmental friendliness deteriorate
Solution Approach 1:
The invention extracts and removes the harmful latex binder component from the conventional airlaid process, replacing it with a hydroentangling mechanism that uses high-pressure water jets to mechanically entangle fibers without requiring any adhesive binders, thereby eliminating non-biodegradable materials while maintaining web strength
Solution Approach 2:
The invention replaces the chemical bonding mechanism (latex binder) with a mechanical bonding mechanism (hydroentangling through high-pressure water jets), where the kinetic energy of water streams mechanically entangles and consolidates fibers into a strong nonwoven web without chemical adhesives
2Object-generated harmful factors
If hydroentangling is used to eliminate binders, then environmental friendliness is improved, but wet strength deteriorates
Solution Approach 1:
The invention optimizes multiple parameters of the hydroentangling process including water jet pressure (typically 50-200 MPa), jet diameter, number of jet banks, and web tension to achieve sufficient wet strength without binders, transforming the hydroentangling process from a weak consolidation method to a strong mechanical bonding system
Solution Approach 2:
The invention uses composite fiber blends combining natural cellulose fibers with synthetic fibers (polyester, polypropylene) or rayon that have different wet strength properties, where the synthetic components provide wet strength retention while the natural fibers provide absorbency and biodegradability, creating a balanced composite material
3Strength
If spunlacing is used to improve wet strength, then wet strength is improved, but cost increases due to bonding fibers
Solution Approach 1:
The invention modifies the hydroentangling parameters to be more aggressive and effective, using higher water jet pressures and multiple jet banks to achieve binderless wet strength that rivals or exceeds spunlaced products, eliminating the need for expensive bonding fibers while maintaining performance
Solution Approach 2:
The invention extracts and eliminates the bonding fiber component from the conventional spunlacing process, achieving wet strength through optimized hydroentangling of the base fiber blend alone, thereby removing the additional cost of bonding fibers while maintaining or improving wet strength performance
4Productivity
If continuous operation is implemented, then productivity is improved, but process complexity increases
Solution Approach 1:
The invention combines the airlaid web formation process with the hydroentangling consolidation process into a continuous integrated operation where the airlaid web is directly fed into the hydroentangling unit without interruption, eliminating batch processing steps and achieving continuous production of binderless nonwoven webs with high 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
The method achieves nonwoven webs with high wet tensile strength, low lint and dust content, and improved absorbency, suitable for industrial wipes, while being economically efficient and environmentally friendly.
Implementation Method 1
the bonding fibers are bi-component fibers composed of a core and sheath structure wherein the sheath contains or is made of a polymer having a melting point lower than the melting point of the polymer or polymer composition of the core
Implementation Method 2
drying and thermobonding the hydroentangled web to obtain the nonwoven web; wherein the drying and the thermobonding take place simultaneously in the drying unit
Implementation Method 3
hydroentangling the airlaid web to consolidate the web on at least one side
Implementation Method 4
airforming the mixture to obtain at least one homogeneous airlaid web
Data Source
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AI summary
A method to prepare nonwoven webs suitable for use as an industrial wipe which have good MD and CD strength is provided. The method includes hydroentangling an airlaid web of natural cellulose fibers having a fiber length of no more than 3.5 mm, bonding fibers having a fiber length of from 6.0 to 12.0 mm and optionally, manmade fibers having a fiber length of from 6.0 to 12.0 mm. The airlaid web is a homogeneous mat of the natural cellulose fibers, the optional manmade fibers and the bonding fibers and is not laid on a precursor web. No non-fiber adhesive or binder is utilized. The airlayering and hydroentangling are conducted in a continuous operation. The method to manufacture the nonwoven web may include an embossing or crepeing operation.