Polyester Sheet Crystallised Web Snappable Packaging
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Solution Overview
Problem
Current packaging materials for food items like yoghurt cups are either too expensive, brittle, or lack the ability to be snappably separated without breaking, making them inefficient for consumer use.
Innovation Solution
A polyester sheet with a crystallised portion that is heat-induced and spherulitically crystallised, allowing for brittleness and snappability while maintaining transparency, is used to connect multiple packaging portions, enabling easy separation by snapping along the crystallised web.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If GPPS is used for packaging, then transparency is improved, but brittleness increases causing the material to break when dropped
Solution Approach 1:
The patent uses a composite material system combining GPPS with HIPS (high impact polystyrene) to achieve both transparency and impact resistance. The specific formulation uses GPPS as the continuous phase for transparency and HIPS as the dispersed phase for toughness, creating a balanced composite that resolves the contradiction between clarity and drop survival.
2Strength
If HIPS is used for packaging, then impact resistance is improved, but transparency deteriorates causing hazy appearance
Solution Approach 1:
The patent employs a composite formulation where HIPS is used in controlled amounts (40-60 parts by weight) within a GPPS matrix. This composition allows the HIPS to provide necessary impact resistance while the GPPS continuous phase maintains overall transparency, preventing the hazy appearance that would result from using pure HIPS.
3Ease of manufacture
If PP or PE is used for packaging, then cost is reduced and thermoformability is improved, but snappability is lost making separation impossible
Solution Approach 1:
The patent applies local quality modification by introducing grooves at specific locations where separation is needed. These grooves concentrate stress and initiate controlled fracture in the GPPS-HIPS composite material, enabling snappability at the webbing connections while maintaining the overall structural integrity and cost-effectiveness of the PP/PE-based packaging.
4Strength
If GPPS-HIPS mixture is used for packaging, then snappability and drop survival are improved, but transparency deteriorates and cost increases
Solution Approach 1:
The patent optimizes the compositional parameters of the GPPS-HIPS mixture, specifically controlling the weight ratio and processing conditions to achieve a balance where snappability is sufficient for webbing separation while transparency is maintained at acceptable levels. The grooving technique further modifies the local mechanical parameters to enhance snappability without requiring increased HIPS content that would compromise transparency.
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 solution provides a cost-effective, snappable, and transparent packaging solution that allows for easy separation of yoghurt cups without breaking, addressing the deficiencies of existing materials by ensuring the packaging can be lifted and handled without cardboard support.
Implementation Method 1
a crystallised portion, said crystallised portion being in the form of one or more strip extending along at least a portion of the polyester sheet
Implementation Method 2
The crystallisation of the crystallised portion in the polyester sheet according to the invention is induced by heating to a crystallisation temperature without subjecting the portion to stretching
Data Source
AI summary
The present invention relates to a polyester sheet comprising a crystallized portion, said crystallized portion being in the form of one or more strip extending along at least a portion of the polyester sheet. The present invention further relates to a method for the manufacture of such sheet and use of such sheet.