Rigid Foam Panel Cutting for Thin High-Tg Foam Films

Solution Overview

Problem

Existing methods for producing thin foam films from polymers with a glass transition temperature of at least 100°C face challenges such as material loss, dust formation, thermal damage, and pinholes, especially when cutting rigid foams, which limits the production of films thinner than 3 mm without chip formation and results in insufficient elongation at break.

Innovation Solution

A process involving the removal of the foam skin from foam blocks, followed by cutting the remaining portion into panels with specific thicknesses and cell diameters, using techniques like laser or band knife cutting, to produce foam films with average cell diameters between 20 µm and 250 µm and elongation at break between 4%-13%, minimizing waste and thermal damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If rigid foam is cut using heated tensioned wires, then cutting is achieved, but thermal damage occurs to the material

Engineering Contradiction:

Improvecutting capabilityVSAvoidthermal damage

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the heated wire cutting method with a mechanical knife cutting system. The knife is guided by a template to achieve precise cutting of foam panels without thermal damage. This substitution of thermal cutting with mechanical cutting eliminates the harmful thermal effects while maintaining cutting capability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Ease of manufacture

If rigid foam is cut using heated tensioned wires, then cutting is achieved, but material loss or fracture of thin sheets occurs

Engineering Contradiction:

Improvecutting capabilityVSAvoidmaterial loss

Core Design Contradiction:

Ease of manufactureVSLoss of substance

Solution Approach 1:

The patent replaces the heated wire cutting method with a mechanical knife cutting system. The knife is guided by a template to achieve precise cutting of foam panels without thermal damage. This substitution of thermal cutting with mechanical cutting eliminates the harmful thermal effects while maintaining cutting capability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Strength

If foam films are produced with small cell diameters, then mechanical properties improve, but production complexity increases

Engineering Contradiction:

Improveelongation at breakVSAvoidproduction process complexity

Core Design Contradiction:

StrengthVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by selecting and optimizing the polymer material properties before the foaming process. By choosing polymers with specific glass transition temperatures (Tg ≥ 100°C) and controlling the foam expansion ratio during production, the desired small cell diameter structure is achieved in advance. This preliminary optimization of material and process parameters enables subsequent easy cutting and film production without requiring complex post-processing equipment.

Inventive Principle:

Principle #10Preliminary action

4Length of moving object

If thin foam films are produced, then product thickness is reduced, but chip formation during cutting increases

Engineering Contradiction:

Improvefilm thicknessVSAvoidchip formation

Core Design Contradiction:

Length of moving objectVSObject-generated harmful factors

Solution Approach 1:

The patent replaces the heated wire cutting method with a mechanical knife cutting system. The knife is guided by a template to achieve precise cutting of foam panels without thermal damage. This substitution of thermal cutting with mechanical cutting eliminates the harmful thermal effects while maintaining cutting capability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent applies preliminary action by selecting and optimizing the polymer material properties before the foaming process. By choosing polymers with specific glass transition temperatures (Tg ≥ 100°C) and controlling the foam expansion ratio during production, the desired small cell diameter structure is achieved in advance. This preliminary optimization of material and process parameters enables subsequent easy cutting and film production without requiring complex post-processing equipment.

Inventive Principle:

Principle #10Preliminary action

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

This process enables the production of thin foam films with improved mechanical properties and reduced material loss, achieving efficient cutting of rigid foams into thin layers suitable for applications like loudspeakers, with minimal pinholes and waste, and enhanced process stability.

Implementation Method 1

a polymer having a glass transition temperature Tg of at least 100°C

Methodology Applied

Scientific EffectGlass transition:

Implementation Method 2

using techniques like laser or band knife cutting

Methodology Applied

Scientific EffectLaser heating: Laser

Implementation Method 3

heated tensioned wires

Methodology Applied

Scientific EffectThermal cutting:

Data Source

PatentEP4237220B1Process for producing foam panels for the production of foam films

Publication Date: 2024.09.11 EVONIK OPERATIONS GMBH

AI summary

The invention relates to a process for producing foam panels for the production of foam films consisting of a polymer having a glass transition temperature Tg of at least 100°C, characterized in that the average cell diameter measured according to the standard ASTM D 3576 is between 20 µm and 250 µm and less than 20 cells having a diameter > 260 µm are present per m2 and the elongation at break of the foam is 4%-13% measured according to ASTM D 638.