The introduction of thermoplastic elastomers (TPE) blurred the line between plastics and cured elastomers, providing engineers with raw materials to shape desired properties in production parts without the need for laborious curing processes. This section focuses on TPEEs, a specialized subgroup of thermoplastic elastomers.
Thermoplastic polyether-ester elastomers (TPEEs), also known as Thermoplastic Copolyesters (TPC), combine the characteristics of engineering plastics with the flexibility of rubber.
Key Points:
- Synthesis:
- Copolymerization of 1,4-butanediol, tetramethylene glycol with dimethylterephthalate (DMT) or terephthalic acid (PTA)
- Requires high level of technical expertise
- Properties:
- Adjustable hardness (30-82 shore D) by altering soft and hard segment proportions
- Comparable operating temperature range to engineering plastics
- Superior elasticity and dynamic properties
- Functional temperature range: -70°C to 120°C
- Outstanding resistance to oils, acids, bases, and amines
- Excellent resistance to swelling in organic solvents, fuels, and gases
- Chemical resistance increases with hardness
- Vulnerable to water and high temperatures
- Processing:
- Compatible with extrusion, blow molding, and injection molding
- Grade selection crucial for specific applications
- Applications:
- Automotive: dust collectors, body covers, high-performance component connections (e.g., airbags)
- Footwear: soles and heels
- Electrical and electronic: cable covers, antenna casings
- Packaging and textiles: breathable films
- Medical: artificial skin, drug delivery systems
- Other: high-temperature and high-pressure gaskets, gears, impact property enhancers for POM and PBT
- Notable Features:
- Remarkable resistance to fatigue under dynamic loading
- Low fuel permeability (e.g., 60 shore D TPEE shows 1/3 fuel permeability of conventional NBR)
In summary, TPEEs offer a unique combination of properties that make them valuable in various industries, particularly where flexibility, temperature resistance, and chemical resistance are required. Their versatility in processing and wide range of applications make them a significant player in the engineered thermoplastic elastomer market.