Partially Laminated Chub Packaging Web Puncture Resistance
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Solution Overview
Problem
Chub packaging materials face puncture and penetration issues during the heat-sealing and crimping processes in the vertical form fill seal process, leading to package leakage and damage, especially when frozen or heavy, necessitating improved puncture resistance.
Innovation Solution
A partially laminated double wall packaging web is created using two independently manufactured thermoplastic films, with at least one layer of nylon and optional ultra-low density polyethylene, where less than 50% of the facing surfaces are laminated, forming a pattern such as a honeycomb or dots, and using a two-part polyurethane adhesive to enhance puncture resistance while maintaining heat-sealability and oxygen barrier properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a single-layer thermoplastic film is used for chub packaging, then the packaging process is simple and cost-effective, but the puncture resistance is insufficient during crimping and heat-sealing operations
Solution Approach 1:
The patent applies composite materials by combining two different thermoplastic films (nylon and ultra-low density polyethylene) into a laminated structure. The nylon film provides puncture resistance during crimping operations, while the ULDPE film enables heat-sealability. This composite structure resolves the contradiction by achieving both high strength and functional complexity through material composition rather than structural complexity.
Solution Approach 2:
The packaging web is segmented into two distinct functional layers: a nylon film layer for puncture resistance and an ultra-low density polyethylene film layer for heat sealing. Each layer performs its specific function independently, allowing the overall structure to achieve properties that neither material could provide alone, thus resolving the contradiction between strength and complexity.
2Strength
If the facing surfaces of two films are fully laminated, then the heat-sealability is improved, but the puncture resistance during crimping is reduced
Solution Approach 1:
The patent applies local quality by creating a non-uniform lamination pattern where only portions of the facing surfaces are laminated together, leaving other portions unlaminated. This localized approach allows the unlaminated areas to maintain puncture resistance during crimping while the laminated areas provide sufficient heat-sealing capability, thus resolving the contradiction between crimping resistance and heat-sealing reliability.
3Strength
If a thicker single-layer film is used to improve puncture resistance, then the material cost and processing difficulty increase, but the heat-sealability may be compromised
Solution Approach 1:
Instead of using a thicker single-layer film, the patent employs composite materials with two different thermoplastic films of appropriate thicknesses. The nylon film provides puncture resistance without requiring excessive thickness, while the ULDPE film layer ensures proper heat-sealability. This approach maintains ease of manufacture and processing while achieving the required strength, avoiding the costs and processing difficulties associated with thicker single-layer films.
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 partially laminated web exhibits improved puncture resistance, as demonstrated by increased total energy impact absorption values, effectively preventing package leakage and damage during the packaging process, while maintaining cost-effectiveness and formability.
Implementation Method 1
using a two-part polyurethane adhesive to enhance puncture resistance
Implementation Method 2
The longitudinal seal is formed by heat-sealing the overlapping edges of the packaging film as it passes through a sealing device of the VFFS equipment. The heat-sealing process may be accomplished using supersonic sealing, high frequency sealing and a hot-air knife sealing system.
Implementation Method 3
each of the two independently manufactured films comprises at least one layer of nylon and has a moisture content of greater than 1% by weight
Data Source
AI summary
The present disclosure is concerned with chub packaging webs with improved puncture resistance suitable for use in chub packaging. The webs have a double waii partially laminated structure. The structure is conveniently formed by adhesively laminating two component films in a face to face configuration using a pattern of adhesive which leaves a substantial portion of the two facing surfaces unlaminated. Preferably, each of the component films comprise at least one layer of nylon and has a moisture content of greater than 1% by weight such that the double wall partially laminated web has a total energy impact absorption value of greater 0.59 foot-pound at −20° C. measured in accordance with ASTM D-7192 test method.