Polyarylene Sulfide Resin Composition for Insert-Molded Products
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Solution Overview
Problem
Polyarylene sulfide-based resin compositions used in insert-molded products face challenges with thermal shock resistance, warpage, and flowability, particularly in complex structures and varying temperature environments, due to differences in thermal expansion coefficients between metal and resin components.
Innovation Solution
A polyarylene sulfide-based resin composition is developed by blending olefinic copolymers with inorganic fillers having different diameter ratios, including fibrous and non-fibrous fillers, to enhance thermal shock resistance and maintain flowability, while reducing warpage and improving dimensional accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polyarylene sulfide-based resin is used to achieve thermal shock resistance, then thermal shock resistance is improved, but toughness deteriorates and the resin becomes brittle
Solution Approach 1:
The invention uses a composite material system combining polyarylene sulfide-based resin with specific inorganic fillers (glass fibers with controlled aspect ratios, silica, alumina) and olefinic copolymers. This composite approach allows the resin to maintain its inherent thermal shock resistance while the inorganic fillers and copolymer matrix provide enhanced toughness and flexibility, preventing brittleness.
Solution Approach 2:
The invention changes the chemical composition parameters of the resin system by incorporating olefinic copolymers with specific functional groups (carboxyl, hydroxyl, or amine groups) at controlled concentrations (1-20 parts by mass per 100 parts resin). This parameter modification transforms the purely crystalline polyarylene sulfide into a more ductile composite system that retains thermal shock resistance while gaining toughness.
2Reliability
If fibrous filler is blended to improve thermal shock resistance, then thermal shock resistance is improved, but warpage increases due to contraction coefficient anisotropy
Solution Approach 1:
The invention applies local quality by using different types of inorganic fillers with different properties in specific combinations. Glass fibers with aspect ratios of 3-10 are used to provide reinforcement and thermal shock resistance, while silica and alumina particles are added to balance the contraction characteristics. This localized optimization of filler types and ratios compensates for the anisotropic contraction of the polyarylene sulfide resin, reducing warpage while maintaining thermal shock resistance.
Solution Approach 2:
The composite material system combines multiple inorganic fillers (glass fibers, silica, alumina) with the polyarylene sulfide resin to create a balanced formulation. The glass fibers provide structural reinforcement and thermal shock resistance, while the silica and alumina particles help balance the contraction coefficients, reducing anisotropic effects and minimizing warpage during cooling.
3Reliability
If inorganic fillers are added to enhance thermal shock resistance, then thermal shock resistance is improved, but flowability deteriorates
Solution Approach 1:
The invention changes the chemical composition parameters by incorporating olefinic copolymers with specific functional groups (carboxyl, hydroxyl, or amine groups) at controlled concentrations. These copolymers act as lubricants and flow promoters, reducing the friction between inorganic filler particles and the resin matrix. This parameter modification maintains excellent flowability despite the presence of high amounts of inorganic fillers, while still achieving superior thermal shock resistance.
Solution Approach 2:
The olefinic copolymer acts as an intermediary substance between the inorganic fillers and the polyarylene sulfide resin. It improves the interfacial compatibility and reduces friction, enabling smooth flow of the molten composite material during injection molding. This intermediary role allows high filler content for thermal shock resistance without sacrificing flowability.
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 superior thermal shock resistance, low warpage, and improved flowability, effectively addressing the limitations of existing polyarylene sulfide-based resin compositions in insert-molded products, particularly in applications with complex structures and temperature variations.
Implementation Method 1
by combining and blending an olefinic copolymer and, as an inorganic filler to be blended alongside, fibrous fillers having respectively predetermined and different diameter ratios that are different from each other with a polyarylene sulfide-based resin
Implementation Method 2
polyarylene sulfide-based resins are crystalline resins and thus have so-called contraction coefficient anisotropy in which the contraction coefficient of the resin in a cooling process differs between the flow direction of the resin and a direction perpendicular thereto. Due to such contraction coefficient anisotropy, there are cases of warping and sinking occurring
Implementation Method 3
superior thermal shock resistance can be maintained even when used in a resin member of an insert-molded product having a structure in which thermal shock resistance readily declines
Data Source
AI summary
A polyarylene sulfide-based resin composition is disclosed containing a polyarylene sulfide-based resin A, an inorganic filler B, and olefinic copolymers C and D each having predetermined structural units, wherein: the inorganic filler B contains a fibrous inorganic filler B1 having a different diameter ratio of 1.5 or less and a fibrous inorganic filler B2 having a different diameter ratio of 3.0 or more; a mass ratio B1/B2 of the fibrous inorganic filler B1 and the fibrous inorganic filler B2 is 0.2 or more and 5.0 or less; and the contents of the olefinic copolymers C and D are respectively 3 parts by mass or more and less than 19 parts by mass and 3 parts by mass or more and 30 parts by mass or less with respect to 100 parts by mass of the polyarylene sulfide-based resin A.