Peelable Transparent Process Liner for Foamed Plastic

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Solution Overview

Problem

Conventional process liners for continuous foaming of plastics face issues such as chemical absorption, material waste, disposal problems, and lack of transparency, which affect the quality and efficiency of the foaming process.

Innovation Solution

A process liner comprising a transparent support polymer film coated with a peelable polyolefin film, providing mechanical strength, barrier function, and easy separation from the foamed material, allowing for visual inspection and reducing material loss.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If conventional paper liners are used, then cost is reduced and availability is improved, but chemical absorption occurs and disposal problems arise

Engineering Contradiction:
Improvecost and availabilityVSAvoidchemical absorption
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

A polymer coating layer is applied to the paper liner to act as an intermediary barrier between the chemicals and the paper substrate. This coating prevents chemical absorption while maintaining the low cost and availability benefits of paper liners.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The liner is constructed as a composite material combining paper (for low cost and availability) with a polymer coating layer (for chemical barrier properties). This composite structure resolves the contradiction by integrating the advantages of both materials while eliminating their individual disadvantages.

Inventive Principle:
Principle #40Composite materials

2Ease of manufacture

If pure paper liners are used, then cost is reduced, but volatile chemicals evaporate and physical properties of foam change

Engineering Contradiction:
ImprovecostVSAvoidfoam physical properties
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The polymer coating serves as an intermediary barrier that prevents volatile chemicals from evaporating through the paper liner, thereby maintaining the physical properties of the foam while keeping the liner cost-effective.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of manufacture

If untreated paper liners are used, then cost is reduced, but foam sticks to the liner and material waste occurs

Engineering Contradiction:
ImprovecostVSAvoidfoam material waste
Core Design Contradiction:
Ease of manufactureVSLoss of substance

Solution Approach 1:

The polymer coating acts as a release agent intermediary between the foam and the paper liner, preventing adhesion and enabling easy separation. This eliminates foam material waste while maintaining the cost advantages of using paper as the base material.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Ease of manufacture

If paper liners are used, then cost is reduced, but transparency is lost and visual inspection becomes impossible

Engineering Contradiction:
ImprovecostVSAvoidtransparency
Core Design Contradiction:
Ease of manufactureVSIllumination intensity

Solution Approach 1:

The invention transitions from thick opaque paper to thin transparent polymer films that can be supplied on storage reels. These thin films provide the necessary barrier function while allowing light transmission for visual inspection, and their flexibility enables continuous processing.

Inventive Principle:
Principle #30Flexible shells and thin films

5Ease of manufacture

If paper liners are used, then cost is reduced, but mechanical strength is insufficient and liners break easily

Engineering Contradiction:
ImprovecostVSAvoidmechanical strength
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The composite structure combines the low-cost paper substrate with a polymer coating layer that provides enhanced mechanical strength and tear resistance. This resolves the contradiction by maintaining cost-effectiveness while improving durability.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The transition to thin polymer films provides superior mechanical properties including tear resistance and flexibility, enabling the liner to withstand the foaming process without breaking while remaining cost-effective through efficient material usage.

Inventive Principle:
Principle #30Flexible shells and thin films

6Strength

If polymer films are used, then transparency is improved and mechanical strength is enhanced, but thickness must be increased and material waste occurs upon removal

Engineering Contradiction:
Improvemechanical strengthVSAvoidfoam material waste
Core Design Contradiction:
StrengthVSLoss of substance

Solution Approach 1:

The use of thin polymer films provides the necessary mechanical strength and transparency while minimizing material usage. The thin film design enables complete removal from the foam product without significant material waste, resolving the contradiction between strength enhancement and waste reduction.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The polymer film serves as an effective release agent that prevents foam adhesion, allowing clean separation without tearing or leaving residue on the foam product. This intermediary function eliminates material waste upon removal.

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 solution enhances mechanical properties, reduces chemical exposure, prevents material waste, and enables visual quality control during the foaming process, improving the safety and efficiency of the foaming process.

Implementation Method 1

A process liner for the preparation of foamed plastic blocks or slabs, comprising a transparent support polymer film (A) and a transparent peelable polyolefin film (B) provided thereon

Methodology Applied
Scientific EffectAdhesion: Adhesive

Data Source

PatentEP3015239B1Peelable, flexible and transparent process liner
Publication Date: 2021.05.19 MONDI AG

AI summary

The present invention provides a process liner for the preparation of foamed plastic blocks or slabs which exhibits excellent mechanical properties including tear strength, dimensional stability and flexibility while being transparent and allowing easy separation from the produced foam material. The process liner comprising a transparent support polymer film (A) and a transparent peelable polyolefin film (B) provided thereon, wherein the support film (A) has a weight per area of 10 -100 g/m2 and is made of a polymer having a melting point of 130 °C or more according to DSC measurement; and wherein the peelable polyolefin film (B) has a weight per area of 10-50 g/m2 and is made of a polyolefin having a melting point lower than the melting point of the polymer of the support film (A) by 10 °C or more. Furthermore, a method for producing the process liner is provided and a process for the preparation of foamed plastic blocks or slabs in a continuous production line.