Lamitube Density and Layering for Ovality Control

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Solution Overview

Problem

Current plastic packaging materials, such as high-density polyethylene (HDPE) laminated tubes, face challenges with stiffness and ovality, making them difficult to shape into a perfect circular form while maintaining mechanical strength and recyclability.

Innovation Solution

A laminated tube (lamitube) with a top layer and a second layer of ethylene polymer, having a density range of 0.942-0.99 gm/cm3, is developed, allowing for easy recyclability in the HDPE stream and low ovality of 1-8%, achieved through a specific layering and lamination process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If high density polyethylene (HDPE) content is increased to achieve high mechanical strength and recyclability, then the tube becomes too stiff to process into a perfectly circular shape

Engineering Contradiction:
Improvemechanical strengthVSAvoidease of shaping
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The tube is divided into multiple layers with different HDPE content. The first layer has higher HDPE content (50-60%) for mechanical strength and recyclability, while the second layer has lower HDPE content (40-50%) for flexibility and ease of shaping. This segmentation allows each layer to contribute its optimal properties to the overall tube structure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the tube wall have different compositions tailored to specific functional requirements. The first layer (outer layer) is optimized for strength and recyclability with higher HDPE content, while the second layer (inner layer) is optimized for flexibility and processability with lower HDPE content. This local quality differentiation resolves the contradiction between strength and ease of manufacture.

Inventive Principle:
Principle #3Local quality

2Adaptability or versatility

If multi-layer laminated structure is used to enhance properties and aesthetics, then the complexity of segregation and recycling increases

Engineering Contradiction:
Improveproperty enhancementVSAvoidsegregation complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

Both layers of the laminated tube are made from polyethylene materials with similar chemical properties and density ranges (0.942-0.99 gm/cm³). This homogeneity in material class allows the multi-layer structure to provide enhanced properties while maintaining ease of segregation and recycling as a single polymer type, reducing the complexity typically associated with multi-material laminates.

Inventive Principle:
Principle #33Homogeneity

Data Source

PatentUS11872784B2Lamitube and implementations thereof
Publication Date: 2024.01.16 EPL LTD

AI summary

The present disclosure relates to a lamitube comprising: a) a top layer comprising at least one ethylene polymer; and b) a second layer comprising at least one ethylene polymer having a first surface and a second surface, wherein the lamitube has a density in the range of 0.942-0.99 gm/cm3. The present disclosure also discloses a process of manufacturing a lamitube comprising the steps of forming the layers and laminating the layers together, then slitting into reels of desired width in the range of 63-320 mm, followed by tubing from the reels.