Three-Layer Film Composite for Uniform Deep Drawing
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Solution Overview
Problem
Existing deep-drawing films, such as PVC and composite films with cycloolefinic copolymers, suffer from non-uniform deep-drawing effects in the longitudinal and transverse directions, leading to uneven thickness and adhesion issues, and require harmful additives like phthalates.
Innovation Solution
A film composite with at least three layers, comprising outer layers of polyolefin or ethylene vinyl acetate copolymer with polystyrene and a middle layer of cycloolefinic copolymer with ethylene vinyl acetate, providing uniform deep-drawing properties and improved adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If composite films with COC and polyolefin are used, then deep-drawing ease is improved, but non-uniform deep-drawing effect occurs in longitudinal and transverse directions
Solution Approach 1:
The patent applies local quality by assigning different functional roles to different layers of the composite film. The outer layers (polyolefin) provide ease of deep-drawing and flexibility, while the inner layer (COC) provides uniform dimensional stability. This layer-specific functional differentiation resolves the contradiction between ease of operation and manufacturing precision.
Solution Approach 2:
The patent uses a composite material structure consisting of multiple layers with different polymer compositions. The combination of polyolefin (outer layers) and COC (inner layer) creates a material that exhibits both the flexibility needed for easy deep-drawing and the dimensional stability required for uniform results across longitudinal and transverse directions.
2Reliability
If PVC is used as protective film, then good thermoforming properties and UV resistance are achieved, but harmful substances are produced during combustion and health risks arise
Solution Approach 1:
The patent extracts the harmful chlorine-containing component (PVC) from the protective film composition while retaining the essential protective functions. The alternative composite film uses polyolefin and COC layers that provide comparable thermoforming properties and UV resistance without generating harmful combustion products like hydrogen chloride.
Solution Approach 2:
The patent changes the chemical composition parameters of the protective film by replacing PVC with a composite of polyolefin and COC. This parameter change maintains the functional requirements (thermoforming, UV resistance) while eliminating the harmful effects associated with chlorine-containing polymers during combustion.
3Object-generated harmful factors
If TPEs are used as PVC substitutes, then health safety is improved, but long relaxation times and reduced resilience occur
Solution Approach 1:
The patent employs a composite material structure where the outer polyolefin layers provide short relaxation times and high resilience, while the inner COC layer contributes to dimensional stability. This composite approach achieves both health safety (by eliminating PVC and TPEs) and the desired mechanical response characteristics.
Solution Approach 2:
The patent applies local quality by positioning materials with different relaxation characteristics in specific locations within the film structure. The polyolefin outer layers, with their faster relaxation characteristics, are positioned where quick response is needed, while the COC inner layer provides structural stability.
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 film composite achieves a uniform deep-drawing effect in both directions and exhibits excellent adhesion with low relaxation time, outperforming prior art films in stress reduction uniformity and adhesion strength.
Implementation Method 1
A wide variety of shaped bodies are produced industrially by means of train-compression forming... Deep drawing is the train-compression forming of materials, especially metals... into a hollow body open on one side
Implementation Method 2
The restoring forces after deep drawing are low, i.e. the relaxation time is low... The relaxation time τ is the time constant of the exponential curve fit of a specific part of the stress-time curve
Data Source
AI summary
The present invention relates to a film composite (1) comprising at least three film layers (2), (3), and (4), wherein the two outer layers (2) and (4) each independently comprise at least one polyolefin or a mixture of an ethylene vinyl acetate copolymer with a polymer from the group consisting of polyolefin and polystyrene, and the middle layer (3) comprises a cycloolefinic copolymer. The film composite is characterized in that the middle layer (3) further comprises at least one ethylene vinyl acetate copolymer. The present invention further relates to the use of the film composite (1) according to any one of the claims as a protective film for thermoforming applications, particularly with metals, and to a thermoforming film produced accordingly.