Thermoplastic Film Bladder Manufacturing Using Barrier Material
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Solution Overview
Problem
The existing methods for manufacturing inflatable bladders, such as those used in footwear, are costly and time-consuming due to the need for expensive brass tooling and sensitive RF welding techniques, which limit flexibility in producing various configurations and sizes.
Innovation Solution
A method involving the application of a barrier material to one or both thermoplastic films to prevent adhesion during heat and pressure application, allowing for the creation of inflatable compartments without the need for configuration-specific tooling, using techniques like silk-screening or printing to apply the barrier material and then sealing the films together, followed by cutting to form the bladder.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If RF welding or dielectric welding is used to attach thermoplastic films, then strong bonds and precise patterning are achieved, but the process becomes costly and time-consuming due to expensive brass tooling and sensitivity to film thickness
Solution Approach 1:
The patent replaces the mechanical RF welding system with a thermal lamination system using heated rollers. Instead of using high-frequency radio energy to melt and bond thermoplastic films at specific weld lines, the invention applies heat and pressure uniformly across the film surfaces through heated rollers, causing the adhesive-coated films to bond together. This substitution eliminates the need for expensive brass welding dies and complex RF welding equipment, significantly reducing manufacturing costs and tooling requirements while maintaining bond strength.
2Manufacturing precision
If configuration-specific brass tooling is used for welding, then precise weld patterns are achieved, but flexibility to produce various configurations and sizes is limited
Solution Approach 1:
The patent employs universal heated rollers that can accommodate multiple film configurations and sizes without requiring dedicated tooling for each product variant. The rollers apply heat and pressure uniformly across different film layouts, allowing the same equipment to produce various bladder configurations (e.g., different shoe sizes, footwear types, or inflatable article shapes) by simply changing the adhesive pattern or film layout. This multi-functional approach enables precise bonding across diverse configurations while maintaining manufacturing flexibility and rapid product development capability.
3Strength
If conventional heated brass dies are used for welding, then film bonding is achieved, but heat degradation occurs in areas adjacent to weld lines
Solution Approach 1:
The patent applies adhesive material selectively at specific locations where bonding is required, rather than heating and pressing the entire film surface. The adhesive is coated only in the regions that need to bond to the opposing film, and the heated rollers activate this localized adhesive. This approach concentrates the thermal and mechanical energy only where needed for bonding, preventing excessive heat exposure to adjacent film areas and avoiding heat-induced degradation, melting, or structural damage to the thermoplastic material.
4Reliability
If RF welding is used to seal films, then strong seals are formed, but the process requires sufficiently thick films to prevent excessive melting
Solution Approach 1:
The patent changes the bonding mechanism from RF welding (which relies on dielectric heating and requires minimum film thickness to prevent burning through) to thermal lamination with adhesive activation. By using heated rollers with controlled temperature and pressure applied to adhesive-coated film surfaces, the process achieves reliable sealing and bonding without the excessive localized heating that plagues RF welding of thin films. This parameter change in the bonding method allows the use of thinner, more flexible films while maintaining seal integrity and preventing film burnout or structural damage.
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 simplifies and speeds up the manufacturing process, reducing costs and enabling the production of a variety of bladder configurations and sizes with high manufacturing flexibility, eliminating the need for expensive tooling changes and minimizing interruptions in production.
Implementation Method 1
applying a barrier material to one or both thermoplastic films to prevent adhesion during heat and pressure application
Implementation Method 2
sealing the films together
Implementation Method 3
heat and pressure application
Implementation Method 4
followed by cutting to form the bladder
Data Source
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AI summary
The present invention is a method for manufacturing inflatable articles, or bladders for inflatable articles, that is time-efficient, simple, inexpensive and permits the uninterrupted manufacture of numerous and even customized article or bladder configurations and sizes, without expensive configuration-specific, metal tooling. The method includes applying a barrier material disposed between the first and second films, adhering the first film to the second film so that the films are sealed together in areas except where the barrier material has been applied to form at least one inflatable compartment and sealed peripheral edge, and cutting along the sealed peripheral edge to form an inflatable article or bladder. The barrier material may be a paint, ink, paper or surface treatment that effectively prevents the first film from adhering to the second. The inflatable article or bladder of the present invention may be used as or in athletic equipment, for example, including footwear.