Three-Layer Extruded Tier Sheet with Elastomer Core
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Solution Overview
Problem
Conventional thermoplastic tier sheets for supporting empty aluminum cans lack sufficient softness, flexibility, and resiliency, and are prone to delamination and moisture absorption, which affects their structural integrity and longevity.
Innovation Solution
A three-layer laminated extrusion tier sheet with outer layers of polypropylene homopolymer and an inner core layer blended with elastomers like SANTOPRENE®, KRATON®, ethyl vinyl acetate, or thermoplastic olefin, formed through co-extrusion to enhance softness, elasticity, and prevent delamination and moisture absorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional thermoplastic tier sheets are used to support empty aluminum cans, then the basic structural support function is achieved, but the tier sheets lack sufficient softness, flexibility, and resiliency
Solution Approach 1:
The patent applies composite materials by creating a three-layer laminated structure combining polypropylene homopolymer outer layers with a polypropylene copolymer inner core layer. This composite structure provides both the required softness and flexibility for can support while maintaining structural integrity through the engineered layer combination and co-extrusion bonding.
Solution Approach 2:
The patent changes material parameters by incorporating elastomers (SANTOPRENE®, KRATON®, ethyl vinyl acetate, or thermoplastic olefin) into the inner core layer at specific concentrations (2-25% by weight). This parameter modification enhances the softness, flexibility, and resiliency properties while the co-extrusion process maintains structural integrity through controlled bonding.
2Stability of the object's composition
If conventional laminated tier sheets are used, then layer structure is achieved, but the layers are prone to delamination
Solution Approach 1:
The patent merges the three layers into a single co-extruded laminate structure where the layers are formed and bonded simultaneously during the extrusion process. This merging approach creates strong interlayer bonding that prevents delamination, while the integrated structure maintains compositional stability throughout service.
3Object-affected harmful factors
If conventional thermoplastic tier sheets are used, then basic support function is achieved, but the tier sheets readily absorb moisture
Solution Approach 1:
The patent applies local quality by making the outer layers of the laminate specifically resistant to moisture absorption, while the inner core layer provides the necessary softness and flexibility. This localized property assignment allows the tier sheet to resist moisture ingress at the surfaces that contact the environment, protecting the overall structural integrity.
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 tier sheet achieves improved softness, flexibility, and resiliency, preventing can movement and allowing dimensional recovery, while preventing delamination and moisture absorption, thus maintaining structural integrity for repeated use.
Implementation Method 1
the tier sheets must be sufficiently elastic and resilient whereby, after the cans are removed from the tier sheets, the structure comprising the tier sheets can dimensionally recover such that the depressions and impressions, previously formed within the tier sheets, will effectively disappear
Implementation Method 2
A first conventional, PRIOR ART type of tier sheet, currently being manufactured and marketed, is illustrated in FIG. 1 and is generally indicated by the reference character 10. It is seen that the tier sheet 10 comprises a three-layer laminate structure which comprises a pair of outer layers or members 12,14 which are fabricated from a suitable polypropylene homopolymer, and an inner core layer or member 16 which is fabricated from a suitable polypropylene copolymer. The laminate structure 10 comprises a three-layer extrusion
Implementation Method 3
still further, in view of the co-extrusion process, the edge portions of the three-layer laminate are effectively sealed such that the three-layer tier sheet laminate will not readily absorb moisture
Data Source
AI summary
A new and improved tier sheet comprises a three-layer laminated extrusion comprising outer layers of a suitable polypropylene homopolymer, and an inner core layer comprising a suitable polypropylene copolymer blended with a suitable elastomer selected from the group comprising SANTOPRENE®, KRATON®; ethyl vinyl acetate (EVA), and a thermoplastic olefin (TPO). By effectively incorporating the elastomer into the inner core layer of the three-layer laminated extrusion, the tier sheet is provided with the requisite amount of softness, elasticity, and resiliency so as to not only permit the multiplicity of cans to, in effect, form sufficiently deep impressions or depressions within the upper and lower tier sheets as the different tiers or layers of tier sheets and cans are disposed upon the transportation pallet within the tiered array comprising the palletized load such that movement of the individual cans with respect to the upper and lower tier sheets will effectively be restricted and prevented but, in addition, the tier sheet can dimensionally recover whereby the depressions and impressions will effectively disappear so as to thereby enable each tier sheet to be readied for use with respect to supporting and restraining new or additional sets of cans in connection with the formation of subsequent palletized loads. Furthermore, the outer layers will not readily delaminate from the inner core layer, and still further, the extrusion process results in the fact that the edge portions of the three-layer laminate are effectively sealed such that the three-layer tier sheet laminate will not readily absorb moisture.