Fuel Pipe Inner Layer Composition for Low Permeability Extrusion
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Solution Overview
Problem
Existing fuel pipes for motor vehicles, particularly those with fluoroelastomer inner layers, face challenges in minimizing fuel permeability to meet stringent environmental standards such as the PZEV standard, while maintaining mechanical properties and processability during extrusion.
Innovation Solution
A crosslinkable rubber composition is developed, comprising a fluoroelastomer, micronized fluorinated thermoplastic polymer, and an inorganic filler with a high aspect ratio based on phyllosilicates like kaolinite, micas, or talc, which reduces permeability and improves extrusion processability by minimizing slippage and maintaining mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fluoroelastomer-based inner layer is used in fuel pipes, then fuel resistance and swelling resistance are improved, but fuel permeability remains too high to meet stringent environmental standards
Solution Approach 1:
The patent applies composite materials by combining fluoroelastomer with micronized fluorinated thermoplastic polymer powder and high aspect ratio inorganic filler to create a multi-component rubber composition. This composite structure leverages the fuel resistance of fluoroelastomer while adding the permeability reduction capabilities of the fluorinated polymer and inorganic filler, achieving both fuel resistance and low permeability simultaneously.
Solution Approach 2:
The patent changes the physical and chemical parameters of the rubber composition by incorporating specific micronized fluorinated thermoplastic polymer powder with controlled particle size (D50 between 2-20 μm) and high aspect ratio inorganic filler (aspect ratio > 30). These parameter changes optimize the composition for both extrusion processing and fuel permeability reduction, meeting environmental standards while maintaining processability.
2Object-affected harmful factors
If micronized fluorinated thermoplastic polymer powder is added to reduce permeability, then fuel permeability decreases, but extrusion processability deteriorates due to slippage
Solution Approach 1:
The patent uses high aspect ratio inorganic filler as an intermediary substance that mediates between the fluorinated thermoplastic polymer powder and the fluoroelastomer matrix. This inorganic filler acts as a bonding agent that prevents slippage during extrusion while allowing the fluorinated polymer to maintain its permeability-reducing function, thus resolving the contradiction between permeability reduction and processability.
Solution Approach 2:
The patent creates a composite material system where micronized fluorinated thermoplastic polymer powder and high aspect ratio inorganic filler work synergistically within the fluoroelastomer matrix. The inorganic filler compensates for the poor processability of the fluorinated polymer powder, enabling successful extrusion while maintaining the permeability-reducing benefits.
3Ease of manufacture
If high aspect ratio inorganic filler is combined with fluorinated thermoplastic polymer powder, then extrusion processability improves by reducing slippage, but mechanical properties may be compromised
Solution Approach 1:
The patent optimizes the parameters of the inorganic filler by selecting materials with high aspect ratio (> 30) and controlling their distribution within the rubber composition. This parameter optimization ensures that the filler provides sufficient bonding to prevent slippage during extrusion while maintaining adequate mechanical properties through proper dispersion and interaction with the fluoroelastomer matrix.
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 composition achieves reduced fuel permeability and retained mechanical properties, enabling compliance with stringent emission standards and stable extrusion processes, with the synergistic effect of the filler and fluorinated polymer enhancing both fuel resistance and processing efficiency.
Implementation Method 1
reduced permeability in the crosslinked state, both compared to a control composition lacking this combination
Implementation Method 2
a crosslinkable (i.e., non-crosslinked) rubber composition can be obtained that is suitable for forming an extruded inner layer
Data Source
Figure 1a~1b
Figure 2a
Figure 2b
AI summary
The invention relates in particular to a rubber composition suitable for extrusion to form an inner layer (10) of a fuel line for a motor vehicle, a method for preparing this composition, this fuel line, and a fuel supply circuit for a motor vehicle incorporating it. This composition is based on at least one fluoroelastomer (FKM) and comprises a filler and a micronized powder of at least one fluorothermoplastic polymer dispersed in said at least one fluoroelastomer. According to the invention, the composition comprises said micronized powder in an amount greater than 20 parts per 100 parts per elastomer, and the filler comprises at least one inorganic lamellar filler having an aspect ratio greater than 30 and being based on a phyllosilicate selected from kaolinite and micas, or is based on a talc.