Hytrel Seals from Advanced EMC Technologies
by Sara McCaslin, PhD Sara McCaslin, PhD No Comments

Hytrel: A Deep Dive into Its Properties and Applications

Hytrel, a thermoplastic polyester elastomer (TPE) from DuPont, provides an excellent balance between flexibility and strength. Seal engineers know that if a seal is too rigid, it responds to changes in motion or pressure. Too soft, and it fails under heat or chemical attack. And that’s where Hytrel, a thermoplastic polyester elastomer (TPE) from DuPont, finds its niche as it bridges the gap between rubber-like elasticity and plastic-like toughness.

If you are looking for a material that resists fatigue, survives dynamic loads, and endures challenging fluids, then it is time to take a deep dive into Hytrel. This article looks at the science behind it, the different grades available, and where it works best. 

Understanding Hytrel: Structure, Chemistry, and Properties

Hytrel is a block copolymer comprised of alternating hard (polybutylene terephthalate) and soft (polyether) segments. This unique molecular structure type offers excellent versatility, as the hard segments provide mechanical strength, creep resistance, and dimensional stability. In contrast, the soft segments contribute elasticity, impact resistance, and low-temperature flexibility.

Engineers value Hytrel for properties such as:

  • Excellent flex fatigue resistance and rebound resilience, with the ability to flex in multiple directions
  • Wide operating temperature range (cryogenic to +315°F), depending on the grade
  • Very strong chemical resistance to media, including solvents, oils, fuels, and hydraulic fluids
  • An excellent combination of high wear resistance and low compression set
  • Good creep resistance

Additionally, it retains its mechanical properties even at high temperatures and remains flexible even at low temperatures.

Hytrel components can be manufactured in a number of different ways, including thermoplastic processing, extrusion, melt casting, rotational molding, blow molding, and injection molding.

There are two grades of Hytrel available: standard grades, which are the most economical and strike an excellent balance between cost and performance, and high-performance grades, which are ideal for environments where issues like abrasion and tear can be problematic. Each of these grades have ranges of hardness and elastic modulus, all achieved by varying the ratio of soft to hard segments in the molecular structure.

Grades of Hytrel

There are various grades of Hytrel, some of which are summarized here.

Hytrel 4056

This grade offers an excellent combination of toughness and strength over a considerably wide temperature range. It works extremely well for low-temperature and cryogenic applications that require a material that is able to retain flexibility. 

Hytrel 4068 and Hytrel 4069

Both grades offer good flex-fatigue and creep resistance combined with outstanding low-temperature properties. And they can be formed using molding or extrusion. They have a higher melting point and lower elastic modulus than 4056. In addition, there is a food-grade material available: Hytrel 4068FG.

Hytrel 4556

4556 is similar to grades 4068 and 4069, with a low-to-medium elastic modulus. This grade works extremely well for seals and gaskets.

Hytrel 5526 and Hytrel 5556

In terms of general properties, these particular grades provide a good balance. Its flow properties, however, primarily limit it to injection molding and extrusion as the manufacturing method. They also offer a balance of properties with a medium modulus.

Hytrel 4053FG NC010

When food contact grade seals are needed, 4053FG NC010 may be an option. This grade has a low modulus extrusion, and its properties include flex-fatigue resistance, creep resistance, and good low-temperature properties. 

Engineering with Hytrel: Applications and Design Considerations

There are several applications where Hytrel offers excellent performance, starting with sealing for dynamic applications.

Dynamic Sealing

It performs extremely well in reciprocating and rotary seals where flexibility and abrasion resistance are critical. In fact, its ability to recover quickly after deformation reduces leakage in spring-energized and lip seal designs.

Harsh Chemical and Thermal Environments

It’s excellent resistance to fuels, hydraulic oils, and cleaning solvents makes it a solid choice for automotive, aerospace, and industrial systems. Although it is not as inert as PTFE, it still outperforms many rubbers and urethanes in aggressive chemical environments.

Manufacturing and Compatibility

Because Hytrel is a thermoplastic, it can be welded, machined, or molded with high precision. In addition, it bonds well to certain metals and other polymers, making it ideal for multi-material seal assemblies.

Specific Applications

Here is a sample of just some of the applications where it excels:

  • Chassis Suspension Systems
  • Thermoplastic Tubing and Elastomeric Hose
  • Innovative Furniture Design
  • Medical Device Materials
  • Sustainability in Airbag Systems
  • Plastics For Sporting Goods
  • Cable Insulation and Jacketing
  • Polymers for Oil and Gas
  • Food Contact Materials
  • Seals and Gaskets

Limitations

Even with the excellent performance it offers, Hytrel does have limitations. For example, prolonged exposure to hot water or steam can degrade performance, and certain polar solvents may affect long-term durability. In addition, Hytrel does not work well in environments with continuous exposure to aggressive chemicals such as strong acids or halogens, and this is especially true at high temperatures.

Conclusion

Hyrtrel provides a solid middle ground between flexible rubber and rigid polymer solutions. Its resilience, fatigue life, and processability make it a go-to choice for demanding environments. Its balance of strength and elasticity will translate into longer service life, better energy efficiency, and reliable performance under real-world stress.

At Advanced EMC Technologies, we understand that every design challenge requires the right material match. Our engineering team works closely with clients to design Hytrel-based component solutions optimized for temperature, pressure, and chemical exposure. Contact Advanced EMC today to discuss how Hytrel can elevate the performance of your next sealing system.

by Sara McCaslin, PhD Sara McCaslin, PhD No Comments

Injection Molding vs. Precision Machining: Choosing the Right Process for Your Application

Injection molding vs. precision machining: Which process is best for manufacturing polymer components? Each one offers its own distinct advantages that depend on factors such as part geometry, material type, production volume, and performance requirements.

In this blog post, we compare both methods to help you determine the most suitable solution for your project.

Fluoropolymers for Injection Molding | Advanced EMC Technologies

Injection Molding

Injection molding is a high-throughput manufacturing process in which molten plastic is injected into a closed mold under high pressure. The mold defines the final shape of the part, and after cooling, the component is ejected. This method is widely used for thermoplastics and is especially effective for large production runs of identical parts.

Pros

There are several key advantages to injection molding, starting with its scalability and cost efficiency. For example, once tooling is completed, per-unit costs drop significantly. This makes it ideal for high-volume production (typically 5,000 to 10,000+ parts). Cycle times are also fast, usually ranging from 15 to 120 seconds, and because these processes are highly automated, they have reduced labor requirements and overhead. 

Injection molding also produces highly uniform parts with tight tolerances (up to ±0.005″) and excellent surface finish, supporting intricate geometries and undercuts that may be impractical to machine. They are also highly material efficient and support the recycling of sprues and runners.

In addition, injection molding is compatible with a wide range of thermoplastics, including fluoropolymers such as PTFE and PEEK.

Cons

There are some drawbacks to injection molding, as well. There can be high initial tooling costs and a longer lead time because mold design and fabrication both require significant investments of money and time (possibly adding weeks to the project timeline). In addition, parts may be subject to design constraints such as uniform wall thickness and draft angles. 

Some polymers may be more difficult to injection mold because of issues with melt behavior, and there may be high melt temperatures may lead to more complexity. Also, parts may require post-molding annealing to reduce warping and internal stresses.

Precision Machining

Precision machining is a subtractive process that removes material from solid stock to achieve final dimensions. It is particularly suited for high-performance polymers and applications requiring tight tolerances or low production volumes.

Pros

There are significant benefits to using precision machining to manufacture polymer components. For example, it is ideal for prototyping and cost-effective for small runs under 5,000 parts and does not require molds or extensive tooling. And because precision machining does not require mold design and fabrication, it eliminates the significant delays associated with injection molding. 

Precision machining is capable of ultra-tight tolerances, often better than ±0.001″, and results in superior part integrity because of the lack of ‘residual flash’. Residual flash is the excess material that can be left around the parting line in injection molding, which needs to be removed. In addition, machined parts retain the full mechanical, thermal, and chemical properties of high-performance polymers. It can also handle features like threads, deep bores, and undercuts.

Cons

Because machining is a material removal process, there may be much higher waste compared to net-shape processes like injection molding. Machining also becomes less cost-effective as the production volume increases. It also requires specialized knowledge to achieve optimal results with advanced polymers.

Which One Should I Use: Injection Molding vs. Precision Machining

The decision between injection molding vs. precision machining should be based on production volume, material selection, tolerance requirements, design complexity, budget, and lead time. Below is a table that summarizes those factors.

FactorInjection MoldingPrecision Machining
Production VolumeBest for high-volume production (5,000–10,000+ parts)Ideal for low-volume runs and prototyping
Material SelectionSuitable for many thermoplastics; some fluoropolymers are challenging to processBetter suited for difficult-to-mold polymers or specialty high-performance materials
Tolerance RequirementsGood dimensional consistency, but limited by mold shrinkagePreferred for ultra-precise, tight-tolerance components
Design ComplexityExcellent for producing intricate shapes and fine details within mold limitationsMore flexible for unconventional geometries and non-uniform features
Budget & Lead TimeHigh upfront tooling costs; longer lead times for setupLower initial cost; faster turnaround for small batches

Conclusion

For high production volumes with a low per-unit cost, injection molding is usually recommended,especially when part geometry is compatible with mold design. Precision machining, on the other hand, excels in delivering complex, high-performance components in low volumes, where material properties, tight tolerances, or custom features are critical.

Here at Advanced EMC Technologies, our team specializes in both injection molding and precision machining for high-performance polymer components. Whether you need thousands of parts or a single precision prototype, our engineering team is ready to help you choose the optimal manufacturing process. Contact us today to discuss your project requirements.