HT PEK falls within the polyetherketone family semicrystalline polymers, which also includes PEEK and PAEK. Developed by Victrex, a leading PEEK producer, it exhibits advantages on performance compared to these other semicrystalline polyketone materials on several fronts.
A Performance Upgrade to PEEK
Developed by Victrex and available commercially as Victrex HT PEK, one of its key advantages is its glass-transition temperature (Tg) of 160°C (320°F), or 10°C (18°F) above that of PEEK. While comparable at room temperature, HT PEK also retains more strength at elevated temperatures. For example, HT PEK demonstrates more than twice the creep modulus of unreinforced PEEK at 150°C (302°F) – PEEK’s Tg.
Its performance in in dynamic load bearing applications is also excellent. Testing conducted by Victrex showed HT PEK’s wear resistance to be more than threefold that of Victrex’ standard unfilled PEEK. For applications requiring resistance to fatigue failure at high stress levels, HT PEK also outperforms PEEK.
As with all polyetherketones, HT PEK resists long-term exposure to a broad spectrum of chemicals. PEEK, however, is impervious to the widest range of chemicals among members of the polyetherketone family because of the 2x ether (E) to ketone (K) ratio in its polymeric structure.
Unfilled and Reinforced HT PEK
Victrex’ standard unreinforced injection molding grade is designated HT G22 PEK. While its strength is excellent at high temperatures, Drake Plastics also injection molds a 30% glass fiber reinforced grade for components that require more structural rigidity.
Typical HT PEK Applications
The properties of HT PEK make it a solid candidate for applications that require a boost in performance over standard PEEK. Potential applications for HT PEK injection molded components include:
- Seal rings, valve seats, electrical insulators in downhole oil and gas equipment
- Thin-walled bulkhead seals, connectors in electrical submersible pumps (ESPs)
- Heat exchanger components
Drake Plastics’ Capabilities for Injection Molding HT PEK
Drake Plastics offers versatile machine sizes for injection molding a wide range of HT PEK part configurations. Our molding machines are rated between 35 and 300 tons, and turn out precision components from 0.85 grams (0.03 oz.) to 567 grams (20 oz.).
Injection molding conditions for HT PEK include extremely high melt temperatures and a narrow processing window. Drake Plastics employs process technology specifically engineered for these types of polymers. The combination of our melt processing experience and our injection molding technology translate to producing consistently high quality parts from HT PEK and other polyketones.
Analyzing melt flow:
Drake Plastics’ engineers use melt flow analysis to characterize HT PEK and other advanced polymers prior to processing. The analytical approach helps define the best processing parameters, molding equipment set-up and tool design for each polymer and each part configuration we produce.
Technology yields consistent quality and performance:
Drake Plastics’ all-electric molding machines operate consistently, efficiently and cleanly, without the risk of hydraulic fluid leaks.
Our engineers size barrels to each polymer. This minimizes the time a thermoplastic dwells at its melt temperature, avoiding material degradation and ensuring that the optimum properties of the material are preserved in each component we mold.
We also design our control systems specifically for processing high performance polymers. During molding, probes are placed within each mold cavity to monitor temperatures and pressures, and maintain the conditions that optimize the quality and performance of every HT PEK component we produce.
An added capability of Drake Plastic’s molding equipment is our injection- compression technology. It allows us to compress or “coin” parts inside the mold while they are cooling. The post-injection sequence eliminates porosity and voids that can occur especially with heavy-walled molded parts.
Victrex ST PEKEKK: An Option for Higher Temperature Applications
The family of polyketone polymers includes an even higher performance alternative to HT PEK for more demanding applications. Designated Victrex ST PEKEKK, Drake Plastics injection molds the polymer for applications where its 10°C (18°F) glass-transition temperature advantage over HT PEK can be a benefit.
Stock Shapes for Machined HT PEK Prototypes
Drake Plastics offers stock and custom sizes of extruded unreinforced Victrex HT G45 PEK rod and plate. Machinable shapes made from reinforced HT PEK as well as Victrex ST are also available made to order with reasonable minimums. This gives customers the opportunity to have machined prototypes for testing, or production quantities prior to finalizing injection molding tools. Drake Plastics also offers CNC machining services, and provides other machining companies with technical support to produce the highest possible quality machined components made from our stock shapes.
