Phased Intermeshing Rollers for Stronger Trash Bag Side Seals
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Solution Overview
Problem
Conventional thermoplastic films used in bags suffer from continuous deformation patterns leading to weakened seals and potential leaks due to zippering effects and thinning, especially when forming side seals over areas with ring rolling or SELFing.
Innovation Solution
Thermoplastic bags with phased deformation patterns are created by aligning deformation zones relative to the bag's width, eliminating or reducing deformations in seal areas and varying patterns to enhance seal strength and liquid containment, using intermeshing rollers configured to match the bag's width.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If continuous deformation patterns are applied across the entire bag width, then material properties are enhanced, but seal strength is weakened due to thinning and zippering effects
Solution Approach 1:
The deformation pattern is segmented into distinct zones: a first zone with continuous deformation pattern, a second zone with reduced or eliminated deformation, and a third zone with continuous deformation pattern. This segmentation prevents continuous deformation across seal areas, eliminating the zippering effect while maintaining material enhancement in non-seal areas.
Solution Approach 2:
Different zones of the bag are given different deformation characteristics tailored to their functional requirements. The first and third zones have continuous deformation for enhanced material properties, while the second zone has reduced deformation to ensure strong, reliable seals. This local differentiation optimizes both seal strength and overall bag performance.
2Strength
If ring rolling or SELFing is applied across the entire film width, then film strength is improved, but film thickness is reduced leading to pin holes and weak areas
Solution Approach 1:
The film width is divided into zones with different deformation applications. The first and third zones receive continuous deformation (ring rolling or SELFing) for strength enhancement, while the second zone has reduced or eliminated deformation to maintain uniform thickness and prevent pin holes.
Solution Approach 2:
Deformation is applied locally in specific zones rather than uniformly across the entire film. This allows strength enhancement in areas where it is needed while preserving thickness uniformity in seal areas, eliminating the trade-off between strength and thickness consistency.
3Ease of manufacture
If deformation patterns extend continuously from one side of the bag to the opposing side, then processing is simplified, but side seals are weakened due to zippering effect
Solution Approach 1:
The deformation pattern is segmented to create a second zone with reduced or eliminated deformation between the first and third zones. This segmentation prevents the zippering effect at side seals while maintaining relatively simple processing through automated zone-controlled application.
Solution Approach 2:
The deformation pattern follows a periodic structure along the bag width: continuous deformation zone, reduced deformation zone, continuous deformation zone. This periodic variation eliminates continuous deformation across seal areas, preventing zippering while maintaining processing efficiency through systematic zone application.
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
The phased deformation patterns provide stronger seals and improved leak resistance by ensuring uniform thickness and tailored material properties, allowing the bags to absorb forces without tearing and maintain structural integrity.
Implementation Method 1
Incremental stretching of a thermoplastic film typically involves running the film between grooved or toothed rollers. The grooves or teeth on the rollers intermesh and incrementally stretch the film as the film passes between the rollers.
Implementation Method 2
SELFing involves passing a film through intermeshing rollers that press a portion of the film out of plane to cause permanent deformation of the portion of the film in the Z-direction. SELFing a film can increase the elasticity of the film.
Data Source
AI summary
Thermoplastic bags with phased deformation patterns are described. In particular, one or more implementations comprise thermoplastic bags with ring rolling, SELFing, or other deformation patterns phased or aligned relative to the sides of the bags. The phased deformation patterns can allow for reducing or eliminating deformation patterns in areas of the thermoplastic bag in which side seals or other seals are formed. Additionally or alternatively, the phased deformation patterns can provide for zones that provide differing properties (e.g., functional or aesthetic). Such zones can vary aligned along a width of the thermoplastic bag and optionally also vary along a height of the thermoplastic bag. The differing zones can provide the thermoplastic bags with phased deformations that provide leak prevention, liquid containment, and other benefits.