Public interest in sustainable chemistry is on the rise with 62% of chemical companies reporting customer
interest in sustainable applications in
2014 – a 5% rise since 2009.1 The Bioplastic Feedstock Alliance reports that, in the past 15 years, progress in life science technology and agricultural production systems has made it possible to envision a future where renewable carbon from plants replaces fossil carbon in production of chemicals and materials needed by society.2
Eastman Trēva™ engineering bioplastic, a USDA Certified Biobased Product, is a next-generation cellulose-based polymer sourced from sustainably managed forests, not from food sources. For every pound of Trēva produced, approximately 40%–50% by weight is renewable content.3 Its durability ensures engineering-resin performance from a bioplastic. Currently, two commercial grades— GC6011 and GC6021 (with improved impact performance)—are available with more grades being developed.
Biobased Trēva
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Processing Conditions for Trēva
Trēva is a bio-based polymer and should be dried for a minimum of 2 hours at 75°–80°C. Once dried, it can be processed on most general-purpose screws with a length/diameter (L/D) ratio of between 18:1 and 22:1 and a compression ratio range of 2.8:1–3.5:1. The recommended feed section depth of the screw should be greater than 10 mm. Residence time in the barrel and hot runner system should be kept to less than 5 minutes to avoid a shift in color. Trēva is a high-flow material capable of filling thin parts with long flow lengths.
Trēva can be processed on a wide variety of molds and gate designs, including:
− Hot runner molds with thermal or valve gates
− Cold runner molds with edge, web, or fan gates
− Three-plate molds with tunnel or restricted/pinpoint gates
Gate size/thickness range may be 0.7–1.5 mm depending on thickness and size of the molded part and the required part aesthetics. A summary of processing information is shown in table below:
Trēva Processing Summary
|
| Parameter |
GC6011, GC6021 |
| Drying time, h |
2–4 |
| Drying temperature, °F (°C) |
165–186 (75–85) |
| Barrel set temperature, °F (°C) |
440–460 (225–240) |
| Target melt temperature, °F (°C) |
460–480 (240–250) |
| Mold temperature, °F (°C) |
150–190 (65–88) |
| Injection speed, in./s (cm/s) |
1–2 (3–5) |
| Injection pressure, psi (MPa) |
1000–1500 (7–10) |
| Pack/hold/cooling time, s |
2–4/4–6/5–10 |
| Screw recovery speed, rpm |
100 |
| Screw back pressure, psi (MPa) |
100–150 (0.7–1.0) |
| Resident time in melt, min |
3–5 |
Trēva Injection Molding Guidelines
After injection molding, the gates can be easily removed with a CO2 laser as shown in the figure below:
Laser Scoring to Remove Gates
» Continue reading to explore unique performance characteristics of engineering bioplastic Eastman Trēva™ that offer benefits beyond sustainability!