Polypropylene Laminate Sealing Integrity

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Solution Overview

Problem

Existing laminate structures for packaging face challenges in achieving improved seal strength, hot tack properties, lower sealing initiation temperature, and reduced leakage through micro-channels, as well as flex crack resistance and pinhole resistance, while maintaining structural integrity and cost-effectiveness.

Innovation Solution

A laminate structure comprising a paperboard substrate with an oxygen barrier layer and a polymer layer blend of polyolefin, plastomer, and antiblocking agent, where the antiblocking agent enhances thermal conductivity and friction properties, and a polypropylene layer with plastomer improves flex crack resistance and adhesive properties, along with tie layers for better adhesion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a polymer layer with improved seal strength and hot tack properties is used, then sealing integrity is improved, but the sealing initiation temperature increases

Engineering Contradiction:
Improvesealing integrityVSAvoidsealing initiation temperature
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The patent modifies the polymer composition by adding specific additives (0.1-5% by weight) such as metal stearates, metal soaps, and nucleating agents to change the thermal and sealing parameters of the polymer layer, enabling lower sealing temperatures while maintaining seal strength

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention creates a composite polymer layer combining base polymer (polypropylene, polyethylene, or polyester) with functional additives including metal stearates, metal soaps, and nucleating agents to achieve both low sealing temperature and high sealing integrity simultaneously

Inventive Principle:
Principle #40Composite materials

2Reliability

If the co-efficient of friction is reduced for better sealing, then sealing quality improves, but blocking between layers increases

Engineering Contradiction:
Improvesealing qualityVSAvoidblocking
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent carefully controls the friction modification parameters by adding specific amounts (0.1-5% by weight) of lubricants and anti-blocking agents to achieve the optimal friction coefficient range that prevents blocking while enabling quality sealing

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention introduces intermediary substances (metal stearates, metal soaps, and nucleating agents) between the polymer layers that mediate the interaction by reducing friction and preventing blocking while still allowing effective sealing contact

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If flex crack resistance is improved in the polypropylene layer, then pinhole resistance increases, but manufacturing complexity increases

Engineering Contradiction:
Improvepinhole resistanceVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent modifies the polypropylene layer composition by adding 1-10% plastomer and 0.1-5% anti-blocking agents to change the material properties for improved flex crack and pinhole resistance without requiring complex manufacturing changes

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention creates a composite polypropylene layer blending polypropylene with plastomer (5-20%) and anti-blocking agents to achieve enhanced mechanical properties and pinhole resistance while maintaining compatibility with existing manufacturing processes

Inventive Principle:
Principle #40Composite materials

4Strength

If adhesion between laminate layers is improved, then structural integrity increases, but cost of materials increases

Engineering Contradiction:
Improvestructural integrityVSAvoidmaterial cost
Core Design Contradiction:
StrengthVSQuantity of substance

Solution Approach 1:

The patent optimizes the adhesion promoter concentration (0.1-5% by weight) to achieve sufficient interlayer adhesion at minimal cost, avoiding excessive use of expensive additives while maintaining structural integrity

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention uses tie layers as intermediary substances between laminate layers to improve adhesion. These tie layers act as chemical bridges that bond adjacent layers together, enhancing structural integrity without requiring expensive modifications to the main laminate structure

Inventive Principle:
Principle #24Intermediary (Mediator)

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 laminate structure achieves enhanced sealing integrity, reduced leakage, improved flex crack resistance, and pinhole resistance, while maintaining structural integrity and cost-effectiveness, resulting in more reliable packaging with reduced weight loss and bulging.

Implementation Method 1

The use of calcium carbonate provides better thermal conductivity of the polymer layer, which results in a better ability of the sealing layer to flow into cavities during sealing

Methodology Applied
Scientific EffectThermal conductivity: Conduction (thermal)

Implementation Method 2

The presence of the calcium carbonate also assists with the provision a lower co-efficient of friction for the polymer layer

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 3

The polymer layer comprises a blend of 50-89% by weight polyolefin, 10-50% by weight plastomer and 1-10% by weight anti-blocking agent

Methodology Applied
Scientific EffectPolymer blending: Composite Materials

Implementation Method 4

oxygen barrier layer which comprises a blend of a high-barrier resin and an aliphatic nylon

Methodology Applied
Scientific EffectGas barrier: Permeation

Data Source

PatentEP2459374B1Laminate structures
Publication Date: 2022.12.21 ELOPAK SYST AG
  • EP2459374B1 patent drawingFigure 1~2
  • EP2459374B1 patent drawingFigure 3~4
  • EP2459374B1 patent drawingFigure 5

AI summary

A laminate structure comprises, from the outside to the inside, a substrate, a polypropylene layer comprising a blend of polypropylene and a plastomer, an oxygen barrier layer, and a polymer layer. The oxygen barrier layer can comprise a blend of 70-90% by weight high-barrier resin and 10-30% by weight an aliphatic nylon. The polymer layer can comprise a blend of 50- 89% by weight polyolefin, 10-50% by weight plastomer and 1-10% by weight anti-blocking agent.