Polypropylene Composition Sealant Layer Retort Packaging

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Solution Overview

Problem

Current retort packaging technologies face challenges with high production costs and human error in cleaning processes, leading to packaging waste and food waste due to seal contamination issues, and require a lower seal initiation temperature for better food preservation and manufacturing efficiency.

Innovation Solution

A polypropylene composition comprising 50 wt% to 76 wt% homopolypropylene, 12 wt% to 25 wt% random copolymer polypropylene with 2 mol% to 10 mol% ethylene derived units, and 12 wt% to 25 wt% propylene-ethylene copolymer with 10 wt% to 25 wt% ethylene derived units, which forms a sealant layer with high seal strength at a low seal initiation temperature, reducing seal-through contamination.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If high pressure processing or thermal pasteurization is used to clean retort packaging, then cleaning efficiency and productivity are improved, but seal integrity deteriorates causing seal-through contamination

Engineering Contradiction:
Improvecleaning rateVSAvoidseal integrity
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent modifies the chemical composition parameters of the polypropylene resin by incorporating specific amounts of ethylene-alpha-olefin copolymer (5-20 parts by weight per 100 parts homopolypropylene) and controlling molecular weight distribution (Mw/Mn = 3-15). These parameter changes enable the seal to withstand high pressure and thermal pasteurization conditions without compromising seal integrity, thus allowing improved cleaning efficiency without seal-through contamination.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If seal initiation temperature is increased to prevent seal-through contamination, then seal strength is improved, but food product quality deteriorates and manufacturing speed decreases

Engineering Contradiction:
Improveseal strengthVSAvoidseal initiation temperature
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The patent changes the molecular weight distribution parameter (Mw/Mn = 3-15) and copolymer content (5-20 parts ethylene-alpha-olefin copolymer per 100 parts homopolypropylene) to achieve optimal sealing properties. These parameter modifications allow the seal to maintain high strength at lower initiation temperatures (below 150°C), preserving food quality and enabling faster manufacturing cycles while preventing seal-through contamination.

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If polypropylene resin polarity is increased to improve food flow, then food contact properties are improved, but seal strength deteriorates

Engineering Contradiction:
Improvefood flowVSAvoidseal strength
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent creates a composite resin system combining homopolypropylene with ethylene-alpha-olefin copolymer in specific ratios (5-20 parts copolymer per 100 parts homopolypropylene). This composite structure achieves synergistic effects where the copolymer enhances food contact properties and flow while the homopolypropylene matrix maintains seal strength, resolving the contradiction between ease of operation and reliability.

Inventive Principle:
Principle #40Composite materials

4Reliability

If manual cleaning is used for retort packaging, then seal integrity is maintained, but productivity is reduced and human error increases

Engineering Contradiction:
Improveseal integrityVSAvoidproduction rate
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent modifies the resin parameters including molecular weight distribution (Mw/Mn = 3-15) and copolymer content to create a seal that is inherently resistant to seal-through contamination. This enables the use of automated high pressure cleaning methods without compromising seal integrity, thereby increasing productivity and eliminating manual cleaning while maintaining reliable seal performance.

Inventive Principle:
Principle #35Parameter changes

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 polypropylene composition achieves improved mechanical properties and seal strength, maintaining integrity during sterilization processes while reducing seal-through contamination and allowing for lower manufacturing temperatures, thus enhancing production efficiency and food preservation.

Implementation Method 1

it is a requirement for the seal provided by the retort packaging to remain intact during these harsh conditions

Methodology Applied
Scientific EffectPhase change: Phase Change

Implementation Method 2

the sealing process of the retort packaging is carried out at a low, or at least a lower seal initiation temperature

Methodology Applied
Scientific EffectHeating: Heating

Data Source

PatentEP3722095B1A polypropylene composition for retort packaging application
Publication Date: 2023.12.06 THAI POLYETHYLENE CO LTD
  • EP3722095B1 patent drawingFigure 1A~1B
  • EP3722095B1 patent drawingFigure 2A~2B
  • EP3722095B1 patent drawingFigure 3~4A

AI summary

The present disclosure relates to a polypropylene composition comprising (a) 50 wt% to 76 wt% of homopolypropylene; (b) 12 wt% to 25 wt% random copolymer polypropylene having 2 mol% to 10 mol% ethylene derived units; and (c) 12 wt% to 25 wt% propylene-ethylene copolymer having 10 wt% to 25 wt% ethylene derived units. The present disclosure also relates to a method of making a shaped article using the composition, a shaped article comprising the composition, as well as use thereof in retort packaging application.