Resin materials with excellent heat resistance, chemical resistance and mechanical strength are indispensable in today's world of high performance products. Aromatic nylons are attracting attention in this context. This article provides detailed information on the characteristics of aromatic nylons, moulding technology, specific moulding conditions, challenges and countermeasures.
What is aromatic nylon?
1. nylon 6T (polyamide 6T)
Repeating unit structure:.
Structural features.
Aromatic ring (C6H4 part):.
This part corresponds to the benzene ring and is responsible for improving hardness and heat resistance.
Amide bond (-CO-NH-):.
Amide bonds form a crystalline structure and improve mechanical strength and chemical resistance.
Methylene chain (CH2) moiety:.
Provides flexibility, but if too long, reduces crystallinity.
Aromatic nylons are high-performance engineering plastics of the polyamide (PA) family with a molecular structure containing benzene rings. This structure gives it the following properties compared to other nylon-based resins.
Main properties.
High heat resistance: maintains its shape even in environments above 200°C
Chemical resistance: high resistance to acids, alkalis and other chemicals
Mechanical strength: excellent tensile strength and abrasion resistance
Dimensional stability: low hygroscopicity and low dimensional change
Overview of molding technology
1) Need for high-temperature molding
Aromatic nylons have a high melting point and require special high-temperature injection molding machines for molding. As it exceeds the melting point of standard polyamide resins, normal molding equipment cannot be used.
Injection temperature: 280-320°C
Mould temperature: 160-180°C
2. mold design and temperature control
Due to the extremely high mold temperatures, general water cooling cannot be used and the following measures must be taken
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Use of cartridge heaters: installed inside the mold to maintain uniform temperatures
Introduction of oil circulation temperature controllers: supporting stable moulding at high temperatures
Moulding challenges and countermeasures
Issue 1: Operational failures due to thermal expansion
When molding in high temperature environments, there is a risk of operation faults due to thermal expansion of the mold.
Countermeasure: Clearances (gaps) are provided in the moving parts of the mold, and the design is designed to absorb the expansion.
Issue 2: Special specification of the molding machine
High-temperature injection is difficult with general-purpose molding machines, and special specifications are required for the molding machine itself.
Measure: Introduction of high-temperature injection equipment.
Select a moulding machine with precise control functions for injection pressure and temperature.
Challenge 3: Limitations of control equipment
General-purpose products such as temperature controllers and heaters may have a short service life.
Solution: produce the necessary equipment in-house and improve maintainability.
Aromatic nylon applications
The excellent properties of aromatic nylons make them suitable for use in
Automotive parts
Engine peripheral parts
Fuel system hoses and tanks
Electronic and electrical components
Connectors, insulating components and sensors
Industrial machinery parts
Gears and bearings requiring wear resistance
Aerospace industry
Application to high-temperature, high-strength parts
Specific molding examples
Sanko Gosei Co., Ltd. utilises the properties of aromatic nylons to mold the following products
High-temperature endurance engine parts
Connectors for electrical insulation
Sliding parts (gears, rollers)
By optimising the molding conditions, the company is able to mass-produce high-precision, high-performance parts.
Future prospects and challenges
Outlook.
Pursuit of lighter weight and higher functionality: aromatic nylons can pursue further weight reduction as a metal substitute material.
Accelerated global expansion: the market for sustainable materials is expected to grow as environmental regulations are tightened worldwide.
Challenges
Controlling material costs: despite its high performance, the cost is high, so improving the efficiency of the manufacturing process is a challenge.
Further development of processing technology: the development of higher temperature and higher precision molding technology is required.
Conclusion.
Aromatic nylons are the next generation of engineering plastics with high heat resistance, chemical resistance and mechanical strength. With the help of special molding technology, it is expected to find applications in a wide range of fields, including automotive parts, electronic devices and industrial machinery.
It will continue to play an active role in more and more industrial fields in the future, thanks to the evolution of molding technology and the increasing performance of equipment.
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