Multilayer Thermoplastic Bag Structure for Higher Dart Impact Resistance
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Solution Overview
Problem
Thermoplastic bags used as liners for refuse containers are prone to tears, rips, and punctures, leading to liquid and solid waste leakage and spillage due to heavy weight and sharp objects, necessitating improved dart impact resistance.
Innovation Solution
Thermoplastic bags are manufactured with multiple films that are initially lightly laminated and then delaminated, featuring bonds aligned with deformations to misalign stress concentrations, enhancing dart impact resistance by allowing films to move relative to each other and absorb forces through bond failure before film failure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If multiple films are laminated together to form thermoplastic bags, then the bags gain structural integrity and strength, but stress concentrations and weak points align across layers reducing puncture resistance
Solution Approach 1:
The patent divides the continuous lamination bond into discrete segments by introducing deformations (such as ribs, dimples, or raised patterns) that create localized bonding points. These deformations segment the stress distribution across the film layers, preventing continuous stress propagation and aligning weak points across layers. The segmented bonding structure maintains structural integrity while reducing puncture resistance by distributing impact forces across multiple independent bonding zones.
2Reliability
If films are delaminated to misalign stress concentrations, then puncture resistance increases, but structural integrity and seal strength decrease
Solution Approach 1:
The patent applies local quality by creating different bonding characteristics in different regions of the film structure. Deformations are introduced at specific locations (such as at regular intervals or in patterns) to create localized non-bonded zones, while other regions maintain continuous bonding. This localized delamination approach misaligns stress concentrations at deformation points to improve puncture resistance, while preserving bond strength in non-deformed regions to maintain overall seal integrity.
3Reliability
If bonds are broken to delaminate films, then dart impact resistance improves, but manufacturing complexity increases
Solution Approach 1:
The patent implements preliminary action by pre-forming deformations (such as ribs, dimples, or raised patterns) into the film structure during the extrusion or forming process, before the bag is put into service. These deformations are created using standard extrusion dies or forming tools, and the bonding characteristics are established during the initial lamination process. The deformations are designed to naturally create misalignment of stress concentrations without requiring additional post-manufacturing processing steps to break bonds or delaminate films.
Data Source
AI summary
The present disclosure relates to multilayered thermoplastic bags with deformations such as raised rib-like elements and regions of delamination between layers. In particular, in one or more embodiments, the disclosed thermoplastic bags include a first sidewall and a second sidewall joined together along a first side edge, a second side edge, and a bottom edge, while having an opening opposite the bottom edge. Furthermore, in some embodiments, the disclosed thermoplastic bags have regions of deformations with lamination between layers and other regions of deformations with delaminated layers. The delaminated layers can serve to increase dart impact resistance of the thermoplastic bags.