Silane Crosslinked Glass Run Lip for Heat Resistance
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Solution Overview
Problem
Automobile door glass runs using thermoplastic elastomer (TPE) suffer from inferior heat resistance and scratch resistance, leading to deformation and increased weight due to the use of inorganic fillers, resulting in rattle noise and visibility issues.
Innovation Solution
The glass run incorporates ethylene-α-olefin copolymer with silane crosslinking for the outer and inner lips, excluding inorganic fillers, and uses thermoplastic resin without silane crosslinking for the body, enhancing heat resistance, scratch resistance, and reducing weight by ordinary molding facilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If thermoplastic elastomer (TPE) is used for the lips, then weight is reduced and manufacturing is simplified, but heat resistance and scratch resistance become insufficient
Solution Approach 1:
The patent changes the chemical structure and crosslinking degree of the rubber material from conventional vulcanized rubber to silane crosslinked rubber with controlled crosslinking density. This parameter change achieves optimal balance between heat resistance, scratch resistance, and weight by adjusting the molecular network structure without adding heavy inorganic fillers
Solution Approach 2:
The patent uses composite material structure with silane crosslinked rubber containing organic fillers and reinforcing agents. This composite approach provides enhanced heat resistance and scratch resistance while maintaining lightweight characteristics, avoiding the need for heavy inorganic fillers like metal oxides
2Reliability
If inorganic fillers are added to improve heat resistance, then heat resistance improves, but weight increases
Solution Approach 1:
The patent changes the filling system from conventional inorganic fillers (metal oxides, calcium carbonate) to organic fillers and reinforcing agents compatible with silane crosslinked rubber. This parameter change achieves heat resistance through chemical crosslinking and organic reinforcement rather than heavy inorganic content, reducing overall weight
Solution Approach 2:
The patent replaces the mechanical reinforcement approach (using heavy inorganic fillers to physically strengthen the material) with a chemical approach (silane crosslinking that creates a three-dimensional molecular network). This substitution provides equivalent or superior heat resistance and strength without the weight penalty of inorganic fillers
3Reliability
If conventional vulcanization is used for rubber, then heat resistance improves, but manufacturing complexity and cost increase
Solution Approach 1:
The patent replaces conventional thermal or chemical vulcanization processes with silane crosslinking that can be cured at lower temperatures and with simpler catalyst systems. This substitution simplifies manufacturing by eliminating complex vulcanization facilities while maintaining heat resistance through the crosslinked molecular structure
Solution Approach 2:
The patent changes the curing parameters from high-temperature vulcanization (requiring specialized equipment and long cycle times) to low-temperature silane crosslinking (using moisture or mild catalysts). This parameter change enables production using standard injection molding equipment, reducing manufacturing complexity and cost while achieving comparable or superior heat resistance
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 provides lips with improved heat resistance and scratch resistance, preventing deformation and rattle noise, while maintaining a low weight and ensuring the body's straightness and transformability during assembly.
Implementation Method 1
The outer-cabin side lip (25) and the inner-cabin side lip (26) include an ethylene-α-olefin copolymer to which a silane crosslinking is applied
Implementation Method 2
the lips include material excellent in the compression set... the lips are insufficient in heat resistance
Data Source
AI summary
A glass run for guiding a door glass in a frame includes: a body including an outer-cabin side wall, an inner-cabin side wall, and a connecting wall which connects the side walls and forms a channel; an outer-cabin side lip which extends toward an inside of the channel from the outer-cabin side wall and is slidably brought into contact with an outer-cabin side surface of the door glass; an inner-cabin side lip which extends toward the inside of the channel from the inner-cabin side wall and is slidably brought into contact with an inner-cabin side surface of the door glass. The outer-cabin side lip and the inner-cabin side lip include an ethylene-α-olefin copolymer to which a silane crosslinking is applied. The body includes a thermoplastic resin to which the silane crosslinking is not applied.