Intermittent Elastic Section Welding Without Adhesives
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Solution Overview
Problem
Existing methods for producing elastic webs for absorbent sanitary products require the use of adhesives to fix elastic sections, which can be undesirable.
Innovation Solution
An apparatus and method that uses a repitch device with suction chambers and an ultrasonic welding unit to space and weld discrete elastic sections between nonwoven webs without adhesives, employing a rotary repitch device and an anvil roller with suction sections and protruding teeth to maintain tension and secure the elastic sections during welding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If adhesive is used to fix elastic sections to continuous web, then attachment strength is improved, but product complexity and environmental concerns worsen
Solution Approach 1:
The invention extracts and removes the adhesive component from the elastic web construction process. Instead of using adhesive to attach elastic sections to the continuous web, the patent employs mechanical attachment methods where elastic sections are directly secured to the web through integrated fastening mechanisms, eliminating the need for separate adhesive application steps and reducing product complexity.
Solution Approach 2:
The invention replaces the chemical bonding mechanism (adhesive) with a mechanical attachment system. Elastic sections are attached to the continuous web through mechanical means such as integrated fasteners, clips, or interlocking structures that provide secure attachment without requiring adhesive substances, thereby simplifying the overall product design.
2Reliability
If adhesive is used to fix elastic sections, then attachment reliability is improved, but environmental harm worsens
Solution Approach 1:
The invention extracts and eliminates adhesive substances from the elastic web construction process. By removing the adhesive component entirely, the patent prevents environmental harm associated with adhesive production, application, and disposal while maintaining attachment reliability through alternative mechanical attachment methods.
Solution Approach 2:
The invention employs disposable mechanical fastening elements that can be easily manufactured and discarded without environmental concern. These simple mechanical components replace complex adhesive systems, providing reliable attachment while being environmentally friendly due to their simplicity and lack of chemical substances.
3Object-generated harmful factors
If ultrasonic welding is used to attach elastic sections, then adhesive elimination is achieved, but energy consumption increases
Solution Approach 1:
The invention employs periodic ultrasonic welding pulses to attach elastic sections to the continuous web. Rather than continuous energy application, the ultrasonic welding process uses intermittent high-frequency vibrations applied only at specific attachment points and moments, thereby reducing overall energy consumption while achieving effective bond formation without adhesives.
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 the production of composite elasticized webs with intermittent elastic sections fixed exclusively by welding, eliminating the need for adhesives and ensuring secure attachment of elastic sections to nonwoven webs.
Implementation Method 1
a rotary repitch device and an anvil roller with suction sections and protruding teeth to maintain tension
Implementation Method 2
an ultrasonic welding unit to space and weld discrete elastic sections between nonwoven webs without adhesives
Data Source
AI summary
Apparatus for producing a composite elasticized web (80) with intermittent elastic sections (72'), comprising: - a tensioning unit (12) for tensioning in a longitudinal direction a continuous elastic film (72), - a cutting and repitch unit (14) comprising a knife roller (26) and a rotary repitch device (24) comprising a plurality of transport units (32) and a plurality of anvils (30) cooperating with the knife roller (26) for transversely cutting the continuous tensioned elastic film (72) and forming a succession of discrete sections of elastic film (72'), wherein the transport units (32) hold by suction respective discrete sections of elastic film (72') and distance them from each other by a predetermined pitch (P), - a welding unit (16) comprising an anvil roller (60) and a welding head (62) cooperating with the anvil roller (60), wherein the anvil roller (60) has at least one suction section (86) including a plurality of suction holes (88) connected to a source of subatmospheric pressure and a plurality of projecting teeth (90) cooperating with said suction holes (88) and having head surfaces forming counter-welding surfaces which cooperate with said welding head, - a tangency zone (68) between the transport unit (32) and the anvil roller (60) in which the respective discrete sections of elastic film (72') are transferred to said at least one suction section (86) of the anvil roller (60), - a first feeding system (64) for feeding a first web material (76) to the anvil roller (60) upstream of said tangency zone (68), and - a second feeding system (66) for feeding a second web material (78) to the anvil roller (60) between said point of tangency (68) and said welding head (62).