Spunbonded Fabric Roller Transfer and Hydroentanglement
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Solution Overview
Problem
Existing systems for producing spunbonded nonwovens from endless filaments face challenges at high speeds due to insufficient energy input for bonding, leading to issues like filament sticking and the need for complex water removal processes, which limit operating speed and web uniformity.
Innovation Solution
A system where endless filaments are transported dry and uncompacted on a first depositing belt at high speeds, using a roller to create a small angle of wrap and friction, allowing for efficient transfer to a second belt without suction, facilitating hydroentanglement for bonding and structure without pre-consolidation, and enabling high-speed production of lightweight nonwovens.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If thermal calender is used for bonding nonwoven web, then good strength and low thickness are achieved, but energy input into the center of the product is limited and heating to near melting point is insufficient for heavier or more voluminous filament deposits
Solution Approach 1:
The bonding process is divided into two distinct stages: first, thermal calender bonding for initial web formation and strength, then hydroentanglement bonding for additional reinforcement. This segmentation allows each bonding method to operate within its optimal energy and effectiveness range, with the calender providing initial structure and the hydroentanglement adding strength without requiring excessive energy input for heating thick sections.
Solution Approach 2:
The thermal calender performs preliminary bonding to create a stable web structure with basic strength and low thickness before the hydroentanglement process. This preliminary action prepares the web by establishing initial adhesion between filaments, reducing the energy required for subsequent bonding steps and preventing filament distortion during transfer.
2Ease of operation
If suction roller is used to transfer filaments from first to second depositing belt, then transfer is enabled, but undesired distortions occur at high speeds
Solution Approach 1:
The suction roller transfer mechanism is completely removed from the system. Instead, the web is transferred directly from the first depositing belt to the second depositing belt through controlled detachment and re-deposition, eliminating the suction roller and its associated distortion problems while maintaining transfer capability.
Solution Approach 2:
The second depositing belt acts as an intermediary surface that receives the web directly from the first depositing belt. The web is temporarily held on the first belt, then transferred to the second belt where hydroentanglement bonding occurs, providing a smooth transition without mechanical intervention that could cause distortion.
3Productivity
If calender rollers are used for pre-bonding at high transport speeds, then production speed is increased, but not enough energy can be transferred into the endless filaments due to short dwell time
Solution Approach 1:
Hydraulic needling or water jet bonding replaces thermal calender bonding for the second bonding stage. This hydraulic/pneumatic method transfers energy through mechanical penetration and water jet impact rather than thermal conduction, enabling effective bonding at high transport speeds where thermal energy transfer would be insufficient due to short contact time.
Solution Approach 2:
The bonding mechanism changes from thermal energy transfer (calender) to mechanical/hydraulic energy transfer (needling or water jets). This parameter change allows the system to maintain effective bonding energy transfer at high speeds, as mechanical penetration and water jet impact are less dependent on dwell time than thermal conduction.
4Reliability
If water is introduced for pre-moistening the fleece web, then coefficients of friction are increased and air movements are reduced, but water has to be removed from the fleece in a further complex process step
Solution Approach 1:
The pre-moistening step and associated water removal process are completely removed from the system. The patent achieves process stability and reduced air movements through alternative means (controlled hydroentanglement bonding) without introducing water that would require subsequent removal, thereby simplifying the overall process.
Solution Approach 2:
Instead of using water to increase friction and control air movements, the system relies on the natural friction between filaments and controlled hydroentanglement bonding. The water used in hydroentanglement serves its primary bonding function while the process parameters are controlled to avoid excessive moisture that would require removal, converting the potential harm of moisture management into a beneficial bonding mechanism.
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
Enables high-speed production of lightweight spunbonded nonwovens with improved adhesion and reduced sagging, allowing for efficient detachment and bonding without pre-consolidation, enhancing the uniformity and strength of the final product.
Implementation Method 1
a roller being arranged at the end of the first depositing belt or at the beginning of the second depositing belt, so that the continuous filaments are guided around the roller with a small angle of wrap
Implementation Method 2
on the second deposit belt at least one device for hydroentanglement of the continuous filaments to a spunbonded nonwoven is arranged
Data Source
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AI summary
The present invention relates to a system (1) and a method for producing a spunbond nonwoven fabric, comprising a spinnerette with a diffuser (2) for producing continuous filaments (3), with a first depositing belt (4) configured to transport the continuous filaments (3) and transfer them to a subsequent second depositing belt (7), wherein at least one device for water jet bonding of the continuous filaments (3) to form a spunbond nonwoven fabric (11) is arranged on the second depositing belt (7), wherein the spunbond nonwoven fabric (11) is subsequently bonded and/or structured by means of at least one further water jet bonding.The invention is characterized in that the first conveyor belt (4) transports the continuous filaments (3) dry and unconsolidated, wherein a roller (8) is arranged at the end of the first conveyor belt (4) or at the beginning of the second conveyor belt (7), so that the continuous filaments are guided around the roller (8) with a small wrap angle.