Elastic Composite Tape With Intermittent Sections
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Solution Overview
Problem
Existing methods for producing elastic composite tapes for absorbent sanitary products face challenges in reliably welding nonwoven materials without intermediate elastic films, particularly in the waist regions and side zones, where the absence of elastic films complicates the production of reliable welds due to the presence of materials with different chemical and physical natures.
Innovation Solution
An apparatus and method that form elastic composite tapes with intermittent elastic sections spaced alternately by different pitches, using a feeding and tensioning unit, a cutting and pitch-varying unit, and a welding unit, which applies longitudinal tension to a continuous elastic film, cuts it into discrete sections, and welds these sections between nonwoven webs without adhesives using an ultrasonic welding head and suction sections with protruding teeth on an anvil roller.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If adhesive is used to fix elastic sections to continuous sheet, then bonding reliability is improved, but manufacturing complexity and cost increase due to additional adhesive application steps and material layers
Solution Approach 1:
The invention extracts and eliminates the adhesive layer from the elastic composite tape structure. By using ultrasonic welding to directly bond the elastic film to the nonwoven sheets, the adhesive application step is removed entirely, simplifying the manufacturing process while maintaining bonding reliability through the welding mechanism.
Solution Approach 2:
The invention replaces the chemical bonding mechanism (adhesive) with a mechanical/thermal bonding mechanism (ultrasonic welding). The ultrasonic welding head generates vibrations that create friction and heat at the interface between materials, forming strong bonds without requiring adhesive materials or additional application steps.
2Area of stationary object
If elastic film is continuous, then elastic coverage is improved, but welding reliability deteriorates in zones where elastic film is absent due to different material natures
Solution Approach 1:
The invention segments the elastic film into discrete intermittent sections rather than using a continuous film. This segmentation allows the elastic film to be present only where elastic coverage is needed, while creating uniform welding zones between sections where nonwoven materials can be reliably bonded without the interference of elastic film material.
Solution Approach 2:
The invention applies different material configurations to different zones: elastic film sections are placed only in zones requiring elastic coverage, while intermediate zones between sections are designed for reliable welding of nonwoven materials. This local differentiation optimizes both elastic functionality and welding reliability in their respective zones.
3Device complexity
If uniform pitch between elastic sections is used, then manufacturing simplicity is improved, but adaptability to different absorbent core positions deteriorates
Solution Approach 1:
The invention introduces variable pitch between elastic sections, making the spacing dynamic rather than uniform. The pitch varies to accommodate different positions and dimensions of absorbent cores, allowing the elastic composite tape to be adapted to different product configurations while maintaining a consistent manufacturing process through programmed section placement.
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
This approach allows for the reliable production of elastic composite tapes without adhesives, enabling effective welding of nonwoven materials in the waist regions and side zones of absorbent sanitary products, improving the manufacturing process by ensuring consistent and strong bonds between nonwoven materials without the need for intermediate elastic films.
Implementation Method 1
welds these sections between nonwoven webs without adhesives using an ultrasonic welding head
Implementation Method 2
suction sections with protruding teeth on an anvil roller
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
An apparatus for producing an elastic composite tape (80) with intermittent elastic sections (72'), comprising: - a tensioning unit (12) for longitudinally tensioning a continuous elastic film (72), - a cut and repitch unit (14) comprising a knife roller (26) and a repitch device (24) comprising a plurality of transport units (32) and a plurality of anvils (30, 30') cooperating with the knife roller (26) to transversely cut the tensioned continuous elastic film (72), wherein the transport units (32, 32', 32") retain - by suction - respective discrete sections of elastic film (72', 72") and alternately space them apart from each other by a first predetermined distance (P1) and a second predetermined distance (P2), with the first distance (P1) greater than the second distance (P2), - a welding unit (16) comprising an anvil roller (60) and a welding head (62) that cooperates 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 depression source and a plurality of protruding teeth (90) intercalated to said suction holes (88), and wherein the transport units (32, 32', 32") pass cyclically through a tangency zone (68) with the anvil roller (60), in which they transfer respective discrete sections of elastic film (72', 72") to said at least one suction section (86) of the anvil roller (60), - a first feeding system (64) for feeding a first continuous nonwoven web (76) to the anvil roller (60) upstream of said tangency zone (68), and - a second feeding system (66) for feeding a second continuous nonwoven web (78) to the anvil roller (60) between said tangency zone (68) and said welding head (62).