Multilayer Stretch Film Segmentation for Load Stability and Tear Resistance
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Solution Overview
Problem
Existing stretch films lack improvements in functional properties such as tear resistance, puncture resistance, and elasticity without compromising other properties like load stability and stretchability.
Innovation Solution
A multilayer stretch film comprising specific inner layers made of polypropylene (PP) terpolymer, PP plastomer, and polypropylene-butene random copolymer, with a combination of slip and cling layers, and a core layer of metallocene Linear Low-Density Polyethylene (mLLDPE), optimized for thickness and layer distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the stretch film is designed to exert high force on goods to wrap them tightly, then the force on load is improved, but the tear resistance may deteriorate due to increased stress concentration
Solution Approach 1:
The stretch film is divided into multiple functional layers with distinct materials: an outer cling layer for high force exertion, an outer slip layer for reduced friction, and an inner puncture resistant layer for tear resistance. This segmentation allows each layer to specialize in one function, resolving the contradiction between force application and tear resistance.
Solution Approach 2:
The patent uses a composite multilayer structure combining different polymeric materials (cling layer material, slip layer material, and puncture resistant layer material) to achieve properties that cannot be obtained with a single material. The composite structure enables simultaneous optimization of force on load and tear resistance.
2Length of moving object
If the stretch film is designed to allow high stretch or elongation, then the wrapping length is improved, but the tear resistance after stretching may deteriorate
Solution Approach 1:
The film structure separates the stretching function (handled by the elastic inner layer) from the tear resistance function (handled by the reinforced puncture resistant layer). This allows the film to achieve high elongation while maintaining tear resistance through the specialized inner layer composition.
Solution Approach 2:
The patent modifies the physical and chemical parameters of the inner puncture resistant layer, including material composition and thickness, to optimize both elongation capability and tear resistance. By adjusting these parameters, the film achieves high stretch while maintaining structural integrity.
3Stability of the object's composition
If the stretch film is designed to provide high load stability during transport, then the load stability is improved, but the stretchability may deteriorate due to reduced elasticity
Solution Approach 1:
The multilayer structure divides responsibilities: the outer layers provide load stability through friction control (cling and slip properties), while the inner puncture resistant layer provides stretchability and elasticity. This segmentation resolves the contradiction between load stability and stretchability.
Solution Approach 2:
The patent employs composite materials with different mechanical properties in each layer. The combination of cling layer material, slip layer material, and puncture resistant layer material creates a composite structure that simultaneously achieves load stability and stretchability.
4Area of stationary object
If the stretch film is designed to reduce neck-in during stretching, then the surface coverage is improved, but the tear resistance may deteriorate due to reduced material density
Solution Approach 1:
The film structure separates the neck-in control function (handled by the outer cling and slip layers) from the tear resistance function (handled by the inner puncture resistant layer). This allows optimization of surface coverage while maintaining tear resistance through the specialized inner layer.
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 exhibits enhanced tear strength, reduced neck-in, and improved resistance to puncture, with increased stretchability and load stability, suitable for packaging goods on pallets.
Implementation Method 1
a multilayer stretch film having improved properties over existing stretch films
Implementation Method 2
the stretch film should have adequate tensile strength and elasticity
Data Source
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AI summary
The invention relates to a multilayer stretch film comprising a first skin layer, a second skin layer, at least one first inner layer disposed between the first skin layer and the second skin layer, and at least one second inner layer disposed between the first skin layer and the second skin layer, wherein the at least one first inner layer and/or the at least one second inner layer is substantially comprised of at least one of a polypropylene (PP) terpolymer, a polypropylene (PP) plastomer, or a polypropylene-butene random copolymer. The multilayer stretch film may comprise a plurality of first microlayers and a plurality of second microlayers, wherein the first and second microlayers are arranged in an interspersed fashion, preferably in an alternating fashion. The invention also relates to a method of producing such a multilayer stretch film.