Polyarylene Sulfide Resin Composition for Insert Molding
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Solution Overview
Problem
Insert molded articles face challenges with heat shock resistance and mold deposit formation due to the difference in thermal expansion between metal and thermoplastic resin components, leading to breakage and reduced molding efficiency.
Innovation Solution
A polyarylene sulfide resin composition with a specific viscosity range and olefinic copolymer content, combined with an inorganic filler and antioxidant, to enhance heat shock resistance and flowability while suppressing mold deposits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If copolymer content is increased to improve heat shock resistance, then heat shock resistance is improved, but mold deposit formation increases and flowability decreases
Solution Approach 1:
The patent applies parameter changes by precisely controlling the copolymer content within 1-5 parts by mass per 100 parts of polyarylene sulfide resin, and controlling the melt viscosity within 70-250 Pa·s at 310°C. This quantitative parameter optimization resolves the contradiction by finding the optimal balance point where heat shock resistance is sufficient while mold deposit formation is suppressed and flowability is maintained.
2Object-generated harmful factors
If copolymer content is reduced to suppress mold deposit formation, then mold deposit formation is suppressed, but heat shock resistance decreases
Solution Approach 1:
The patent resolves this contradiction by establishing a lower bound for copolymer content (at least 1.0 part by mass per 100 parts of polyarylene sulfide resin) and combining it with specific viscosity control (70-250 Pa·s). This parameter combination ensures minimum heat shock resistance while suppressing mold deposit formation, avoiding the pitfall of excessive copolymer reduction.
3Ease of manufacture
If high molding temperature is used to improve flowability for detailed structures, then flowability is improved, but mold deposit formation increases
Solution Approach 1:
The patent resolves this contradiction by controlling the melt viscosity of the polyarylene sulfide resin within 70-250 Pa·s at 310°C and optimizing the copolymer content. This parameter control provides inherent flowability improvement without requiring excessive molding temperature, thereby suppressing mold deposit formation while still enabling accurate formation of detailed structures.
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 maintains high heat shock resistance and flowability, effectively reducing mold deposit formation and improving molding efficiency, even at reduced copolymer content, thereby preventing breakage and enhancing the durability of insert molded articles.
Implementation Method 1
a melt viscosity of the polyarylene sulfide resin, measured at 310° C. and a shear rate of 1216 sec−1, is at least 70 Pa·s and at most 250 Pa·s
Implementation Method 2
the coefficient of thermal expansion and coefficient of contraction, caused by a change in temperature, differ greatly between the metal etc. and the thermoplastic resin composition forming the insert molded article
Data Source
AI summary
A polyarylene sulfide resin composition characterized by comprising a polyarylene sulfide resin, and an olefinic copolymer comprising an α-olefin-derived structural unit and an α,β-unsaturated acid glycidyl ester-derived structural unit, wherein the olefinic copolymer content is at least 1.0 parts by mass and less than 5.0 parts by mass with respect to 100 parts by mass of the polyarylene sulfide resin, a melt viscosity of the polyarylene sulfide resin measured at 310° C. and a shear rate of 1216 sec−1 is at least 70 Pa·s and at most 300 Pa·s, and a flow length for a width of 20 mm and a thickness of 1 mm, at a cylinder temperature of 320° C., an injection pressure of 100 MPa and a mold temperature of 150° C., is at least 80 mm and at most 200 mm.