PAS Resin Composition for Laser Welding Without Black Spots
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Solution Overview
Problem
Resin molded articles made from polyarylene sulfide (PAS) resins have insufficient laser transmissivity, which hinders effective laser welding and leads to issues like black spots and reduced welding strength.
Innovation Solution
A PAS resin composition with a weight average molecular weight less than 40,000 and a linear growth rate of crystals of 10 μm/min or less is used, enhancing laser transmissivity and welding strength in laser welding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If high-power laser beam irradiation is used to increase welding strength, then welding strength is improved, but black spots are generated in the resin which cause further interference with laser transmission
Solution Approach 1:
The patent changes the physical parameters of the PAS resin by controlling its weight average molecular weight (less than 40,000) and linear growth rate of crystals (10 μm/min or less). These parameter changes modify the resin's laser transmissivity and crystalline structure, enabling effective laser welding at lower power levels without generating black spots, thus resolving the contradiction between welding strength and black spot generation
Solution Approach 2:
The patent introduces dynamic control of crystal growth during the molding process by maintaining specific temperature conditions (100-200°C for 1-48 hours) that regulate the linear growth rate of crystals. This dynamic control creates an optimal crystalline structure that balances laser transmission and welding strength, preventing the harmful effects of excessive crystal growth while maintaining structural integrity
2Strength
If PAS resin with higher molecular weight is used to improve mechanical strength, then mechanical strength is improved, but laser transmissivity decreases
Solution Approach 1:
The patent precisely controls the weight average molecular weight parameter to be less than 40,000, which is lower than conventional PAS resins. This parameter change optimizes the balance between mechanical strength and laser transmissivity, allowing the resin to maintain sufficient mechanical properties while achieving high laser transmissivity for effective laser welding
3Strength
If crystal growth rate is increased to improve mechanical properties, then mechanical properties are improved, but spherulite size increases reducing laser transmissivity
Solution Approach 1:
The patent implements dynamic control of crystal growth by specifying a linear growth rate of 10 μm/min or less during the molding process. This dynamic parameter control ensures that crystals grow slowly enough to maintain small spherulite sizes (optimal for laser transmission) while still developing the crystalline structure necessary for mechanical strength
Solution Approach 2:
The patent changes the crystal growth kinetics by controlling the linear growth rate parameter. This parameter change results in finer crystalline structures with smaller spherulites that transmit laser light more effectively while maintaining the mechanical integrity required for structural applications
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 PAS resin composition achieves excellent laser transmissivity and welding strength, reducing the occurrence of black spots and improving the overall quality of laser-welded PAS resin molded articles.
Implementation Method 1
a PAS resin molded article for laser welding having excellent laser transmissivity and welding strength in laser welding
Implementation Method 2
irradiation with a high-power laser beam is required for an increase in welding strength
Data Source
AI summary
Provided are a polyarylene sulfide resin molded article for laser welding having excellent laser transmissivity and welding strength in laser welding, a resin composition capable of forming the molded article, and production methods for the same. More specifically, in a polyarylene sulfide resin composition for laser welding containing a polyarylene sulfide resin, a weight average molecular weight of the polyarylene sulfide resin is less than 40,000, and a linear growth rate of crystals of the polyarylene sulfide resin is 10 μm/min or less.