Patterned Adhesive Tape for High Loft Nonwoven Bonding
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Solution Overview
Problem
The challenge lies in securely adhering fasteners to high loft nonwoven materials in disposable diapers without requiring high lamination forces, which can damage equipment and fasteners, and in using relatively hard adhesives effectively while minimizing costs and equipment modifications.
Innovation Solution
A composite tape assembly comprising a fastening tape and a release tape with a patterned adhesive configuration, where the release tape has a hinge component and a length less than the fastening tape, allowing for higher lamination pressures to be applied effectively using existing equipment, thereby improving bonding with high loft nonwovens and enabling the use of harder adhesives.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If high lamination forces are applied to bond fasteners to high loft nonwoven materials, then bonding strength is improved, but equipment damage and fastener deformation occur
Solution Approach 1:
The patent changes the physical state and properties of the adhesive by using a lower melting point adhesive composition. This allows the adhesive to become more fluid at bonding temperature, enabling it to flow into and bond with the lofted fibers of the nonwoven material without requiring excessive lamination force, thus preventing equipment damage and fastener deformation while achieving strong bonding.
Solution Approach 2:
The patent utilizes phase transition of the adhesive from solid to liquid state during the bonding process. The adhesive is applied in a solid or semi-solid state, then heated to melt and flow into the nonwoven fibers, creating strong bonds. After cooling, it solidifies to provide durable attachment. This phase transition enables effective bonding with high loft materials without requiring continuously high pressure.
2Strength
If relatively hard adhesives are used to bond fasteners, then internal strength of adhesive is improved, but lamination forces required increase
Solution Approach 1:
The patent changes the parameters of the adhesive by selecting materials with lower melting points and appropriate viscosity characteristics. This allows the adhesive to achieve sufficient internal strength after bonding while remaining fluid enough during application to bond effectively without requiring high lamination forces. The key is selecting adhesive components that provide the right balance of strength and flowability at bonding temperature.
3Ease of operation
If high loft nonwoven materials are used for softer diapers, then comfort is improved, but bonding difficulty increases
Solution Approach 1:
The patent addresses the bonding difficulty of high loft materials by changing the temperature and viscosity parameters of the adhesive. By using adhesives with lower melting points and appropriate flow characteristics, the adhesive can penetrate and bond with the lofted fibers effectively. This allows manufacturers to use softer, high-loft nonwoven materials for improved comfort while maintaining ease of manufacturing through effective bonding.
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 solution enables secure adherence of fasteners to high loft nonwovens with reduced lamination forces, preserves equipment and fasteners, and achieves cost savings by utilizing conventional lamination equipment and patterned adhesives, enhancing bonding strength and reducing material usage.
Implementation Method 1
an adhesive layer disposed on a first face of the backing film... the hinge component is in the form of a raised region of material extending from the second face of the backing film... the adhesive layer of the release tape is arranged in a pattern configuration
Implementation Method 2
a method of increasing lamination pressure when forming a factory joint... applying a lamination force to the release tape and the article... whereby contact occurs between the at least one region of adhesive and the article and a relatively high lamination pressure is applied
Data Source
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AI summary
The present invention relates to a composite tape (10) from which a closure tab for disposable articles can be cut.