Key Qualities of High-Heat and Specialty Resins
Resin materials used in plastic injection molding have advanced significantly in recent years as combining plastics with fillers and reinforcement materials has become more common in many industrial applications to improve part performance and strength.
In the past, plastics were not considered highly heat resistant materials. Now, it is more well known that there are many high-performance resins that can be used at temperatures up to 572 degrees Fahrenheit – depending on the part/product’s environment and exposure to chemicals. High heat and specialty resins are especially good alternatives to metal because they offer incredible benefits in weight reduction, chemical resistance, and friction characteristics. Plus, these great properties can be maintained at high, continuous operating temperatures.
When reinforcements like glass or carbon are added to high-heat or exotic resins, strength and heat distortion temperatures are improved even further. Especially for aerospace and automotive applications, carbon fiber reinforced plastic provides outstanding stiffness and mechanical properties with low part weight. If blended with lubricants like PTFE and graphite, resins can deliver superior abrasion resistance, wear, and low friction. The naturally good electrical insulating characteristics of these materials can also be engineered to offer static dissipative or electrically conductive properties.
High temperature and specialty resins may cost more upfront than lower-grade resins, but these materials can greatly enhance durability and performance of your complex parts—resulting in reduced overall production costs.
Material Properties to Consider:
Strength and modulus – It’s important to evaluate the mechanical properties of the materials you’re considering at both the low and high ends of the operating temperature range. You need to understand at what elevated temperatures plastics will soften and lose strength/modulus.
Thermal expansion – Compared to metal, plastic has a higher rate of thermal expansion. The coefficient of thermal expansion should be checked to ensure any CTE mismatch between plastic parts and mating metal parts does not lead to malfunction due to dimensional changes.
Creep strain and stress relaxation – At higher temperatures, plastics show increased creep strain and stress relaxation. Keep these factors in mind during your design process and make adjustments as needed.
Degradation – In high temperature environments, plastics can degrade over time, especially if oxygen is present. Review thermal degradation curves when choosing materials for use in elevated temperature environments.
High heat or specialty materials naturally have, or can be designed to have, any of the following properties, which boost performance in extreme environments:
- Low or high thermal conductivity
- Low thermal expansion rates
- Excellent wear resistance
- Good sealing properties
- Long-term thermal stability
- Creep resistance
- Ability to retain mechanical properties at extremely low and high temperatures
- Resistance to hot water and steam
- Abrasion resistance
- Chemical resistance
- Dimensional stability
- Flame resistance
- Transparent / translucent
- Low permeability
Whether you’re working with resins like PEI, PSU, PPS, or PEEK, some high heat or specialty materials have many or all of the properties listed above, and each has distinct key features, heat tolerance, performance benefits, and target markets/industries. This chart identifies these aspects for a wide range of high heat and exotic amorphous and semi-crystalline materials.
An important first step in selecting high heat or specialty resins is to understand the key properties of the materials you’re considering for your specific application. Working with an experienced injection molder who draws on the knowledge of world-class polymer scientists and leading material suppliers will help ensure the best formulations are developed for even the most complex, precision-engineered plastic parts.
Are you searching for the ideal material for developing a complex plastic part? Download this guide to learn more about the features of many common high heat and specialty resins.
