High Strength Bonded Film Using Segmented Core Layers
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Solution Overview
Problem
Conventional plastic films used for trash bags typically rely on a single layer for tensile strength, which limits their overall strength and efficiency, while multi-layer films require multiple extruder machines, increasing complexity and cost.
Innovation Solution
A multi-layer high strength bonded film is developed with two thin core-strength layers bonded together, enhanced by a bonding layer and sealant layers, and processed using a concentric-multilayer polymer structure to achieve greater tensile strength through molecular alignment and stretching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a single layer of strength providing material is used in prior art films, then the film structure is simple, but the tensile strength is limited
Solution Approach 1:
The strength providing material is divided into two separate thin layers (each of thickness Y) bonded together, rather than using a single thick layer. This segmentation allows each layer to achieve better molecular alignment during extrusion, resulting in higher tensile strength for the combined structure compared to a single layer of total thickness 2Y.
Solution Approach 2:
The invention creates a composite structure by bonding two thin strength layers together with a bonding layer in between. This composite configuration leverages the molecular alignment achieved in each thin layer during extrusion to produce superior overall tensile strength compared to a homogeneous single layer of equivalent total thickness.
2Strength
If three-layer films with core-strength layer are used, then tensile strength is improved, but manufacturing complexity increases requiring two extruder machines
Solution Approach 1:
The invention merges the bonding layer and sealant layer functions into a single integrated layer, eliminating the need for separate extruder machines. This allows the film to be produced using a single extruder machine while maintaining the bonded two-layer strength structure, thereby reducing manufacturing complexity while preserving tensile strength improvements.
3Strength
If the thickness of core-strength layer is increased to improve tensile strength, then strength increases, but the draw-down ratio decreases reducing molecular alignment
Solution Approach 1:
Instead of using a single thick core-strength layer of thickness 2Y, the invention segments it into two thin layers of thickness Y each. This segmentation maintains a high draw-down ratio during extrusion, ensuring excellent molecular alignment in each layer, which translates to superior tensile strength compared to a single thick layer with lower draw-down ratio and poorer alignment.
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 film achieves at least 20% greater tensile strength than conventional films of the same gauge, reducing resin material usage and manufacturing costs, while maintaining or improving strength in applications like trash bags.
Implementation Method 1
expanding a radius of the molten concentric-multilayer polymer structure
Implementation Method 2
cooling the expanded concentric-multilayer polymer structure to form a non-molten expanded concentric-multilayer polymer structure
Implementation Method 3
as the molecules flow through the narrow channel they start aligning along the channel's (flow) direction
Data Source
AI summary
A high strength multilayer film includes a film-web having an odd number of layers, the film-web includes a bonding layer located between two core-strength layers, wherein the film-web is formed from a concentric-multilayer polymer structure in which an inner layer of the concentric-multilayer polymer structure includes a bonding material. For the bonding layer of thickness 2*Z and the two strength layers of thickness Y each, the film-web has a tensile strength at yield that is greater than of a film-web that (i) lacks the bonding layer and (ii) includes a single core-strength layer of thickness 2*(Y+Z).