Electron-Beam Crosslinked Grained Film for Soft Low-Gloss Interiors
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Solution Overview
Problem
Existing textured TPO films for motor vehicle components suffer from poor feel due to high hardness, tendency to stick during extrusion, high gloss, and insufficient stability, leading to manufacturing challenges and reduced durability.
Innovation Solution
A method using a polymeric mixture of ethylene-propylene-diene copolymer (EPDM) and thermoplastic polyolefin (TPO) with low Shore A hardness, extruded and treated with electron beams to achieve a gel content of 10-70 wt%, eliminating the need for crosslinking agents and ensuring a soft, low-gloss, and stable film laminate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional TPO films are used to achieve durability and stability, then reliability is improved, but hardness increases leading to poor feel and plastic-like appearance
Solution Approach 1:
The invention changes the material parameters by using a specific TPO composition with controlled gel content (5-50%) and specific polymer ratios (polypropylene 10-50%, ethylene copolymer 50-90%), along with adding 0.1-5% waxy substance to modify the film's hardness and feel while maintaining stability
Solution Approach 2:
The invention creates a composite material system by combining TPO with waxy substances (paraffin, microcrystalline wax, or polyethylene wax) to achieve a balance between hardness, softness, and stability, resulting in a material that feels pleasant to touch while maintaining durability
2Strength
If softness is increased to improve feel, then hardness is reduced, but films stick together during extrusion preventing manufacturing
Solution Approach 1:
The waxy substance acts as an intermediary agent between the TPO polymer chains, reducing intermolecular adhesion and preventing film sticking during extrusion and winding, while allowing the film to maintain sufficient softness for pleasant feel
Solution Approach 2:
The invention optimizes the gel content parameter to 5-50% and adds 0.1-5% waxy substance to change the rheological properties of the TPO, enabling the film to be soft enough for pleasant feel but with reduced sticking tendency during manufacturing
3Illumination intensity
If high gloss is present in TPO films, then appearance is achieved, but coating adhesion is reduced and matting leads to reduced abrasion resistance
Solution Approach 1:
The invention modifies the surface parameters by controlling the gel content and adding waxy substances to achieve a naturally low gloss appearance (gloss value 10-70) that does not require excessive matting of coating layers, thereby preserving abrasion resistance
4Strength
If crosslinking agents are added to achieve texture strength, then gel content increases to 5-80%, but manufacturing complexity and cost increase
Solution Approach 1:
The invention optimizes the gel content parameter to a moderate range of 5-50% (preferably 10-30%) to achieve sufficient texture strength for deep drawing without the need for complex crosslinking agents or excessive processing steps
Solution Approach 2:
The invention extracts or eliminates the need for crosslinking agents by achieving adequate texture strength through optimized TPO composition and controlled gel content alone, simplifying the manufacturing process
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 method produces a film laminate with a pleasant feel, low gloss, and high embossability, suitable for deep-drawn molded parts with improved durability and stability, overcoming the limitations of traditional TPO films.
Implementation Method 1
the film or the top film of the film laminate is textured in an embossing step and then treated with electron beams
Implementation Method 2
treated with electron beams until a gel content of 10 to 70 wt.% is achieved
Data Source
AI summary
The invention relates to a process for producing a coated grained film or a film laminate comprising a coated grained top film and at least one lower film, wherein the polymeric starting mixture is extruded into a film or the top film is coextruded with a lower film into a film laminate or the film as the top film is joined separately to the lower film, and the film or top film is grained in an embossing step and then treated with electron beams. This process is further embodied by the use, for the extrusion, of a polymeric starting mixture comprising an ethylene-propylene-diene copolymer (EPDM) and a thermoplastic polyolefin (TPO), the polymeric starting mixture being largely uncrosslinked, so as to form, after the extrusion, a coated grained film or coated grained film laminate and then to treat the coated grained film or coated grained film laminate surface with electron beams until the gel content established is from 10 to 70 wt%. A further subject of the invention is a coated grained film or a film laminate with a grained surface and the advantageous use thereof as thermoformed mouldings, produced in particular by in-mould injection or compression coating, especially in motor vehicles. Advantageous use also extends, furthermore, to application as unweakened decorative film for airbag covers.