Polypropylene Welding Resin Composition for Welded Joint Durability
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Solution Overview
Problem
Existing resin compositions with added glass fiber and antioxidant in thermoplastic resins suffer from decreased strength and creep life due to thermal degradation at welded surfaces during thermal welding.
Innovation Solution
A resin composition comprising polypropylene, glass fiber, and antioxidant with an oxidation induction time of 30 minutes or longer at 230°C, which prevents oxidative degradation and maintains strength and creep life in high-temperature environments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If glass fiber and antioxidant are added to thermoplastic resin to improve heat resistance, then heat resistance is improved, but strength and creep life of welded portion decrease due to thermal degradation
Solution Approach 1:
The patent changes the chemical composition parameters of the antioxidant package by specifying particular antioxidants (Irganox 1010, Irganox 1076, Irgafos 168) and their precise proportions (0.03-0.06% for phenolic antioxidant, 0.01-0.03% for phosphite antioxidant) to achieve both heat resistance and weld strength. This parameter optimization resolves the contradiction by finding the right chemical composition that prevents thermal degradation while maintaining welded portion strength.
2Temperature
If glass fiber and antioxidant are added to thermoplastic resin to improve heat resistance, then heat resistance is improved, but creep life of welded portion decreases due to thermal degradation
Solution Approach 1:
The patent optimizes the antioxidant package composition with specific proportions of phenolic antioxidant (0.03-0.06%) and phosphite antioxidant (0.01-0.03%) to extend the duration of service (creep life) of welded portions under thermal load. This parameter change ensures long-term durability by preventing oxidative degradation that would otherwise reduce creep life.
3Reliability
If antioxidant is added to prevent oxidative degradation, then oxidation resistance is improved, but production cost increases
Solution Approach 1:
The patent finds the optimal concentration range for antioxidants (phenolic: 0.03-0.06%, phosphite: 0.01-0.03%) that provides sufficient oxidation resistance while minimizing material cost. This parameter optimization resolves the contradiction by achieving reliable oxidation protection at economically viable concentrations, avoiding both under-protection and excessive cost.
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 resin composition ensures high durability and prevents strength and creep life degradation of welded portions, suitable for in-vehicle components, with reduced production costs and environmental impact using recycled materials.
Implementation Method 1
a resin composition for welding contains a thermoplastic resin containing a polypropylene, a glass fiber, and an antioxidant, in which the resin composition has an oxidation induction time of 30 minutes or longer at 230° C.
Data Source
AI summary
A resin composition for welding contains a thermoplastic resin containing a polypropylene; a glass fiber, and an antioxidant, in which the resin composition has an oxidation induction time of 30 minutes or longer at 230° C.