What Should You Know About Using Tritan for Blow Molded Bottles?

Eastman Tritan™ is a type of plastic. It is a copolyester (PCTG). It does not contain bisphenol A (BPA). Tritan is very clear and strong. Different types of Tritan work for different blow molding needs. Extrusion blow molding (EBM) is one way to shape Tritan.

Here are the main Tritan types for extrusion blow molding:

1. Tritan EX401 – For Baby Products:
Made for things like baby bottles and cups.
Has a plant-based helper to get parts out of the mold easily.
It is clear, strong against impacts, resists damage from water and heat, and resists chemicals.
It can handle boiling water or steam cleaning.
Can be shaped using injection molding, injection stretch blow molding, or extrusion blow molding.

2. Tritan EX501 – Stronger for Baby Products:
Also used for baby bottles, nipples, cups, and breast pump parts.
Stays clearer than EX401 after many hot washes. Looks like glass even after many dishwasher cycles.
Has a plant-based mold release helper.
Does not hold smells or tastes much (better than polypropylene).
Very strong if dropped. Lasts long in the dishwasher.
Can be shaped using injection molding, injection stretch blow molding, and extrusion blow molding.

Both EX401 and EX501 are safe for food contact. They handle the repeated cleaning needed for baby items.
The main difference: EX501 stays clearer and odor-free longer after many steamings and washings.

3. Tritan TX1800 – General Blow Molding Plastic:
Made for general extrusion blow molding uses.
Its softening temperature (glass transition temperature) is about 110 °C. This is much higher than PETG plastic (around 80 °C).
TX1800 is very tough. It resists water damage, heat, and chemicals.
It has a very shiny and clear surface.
Good for containers filled with hot liquids (up to 100 °C).
Good for containers that go in the dishwasher.
Used for sports water bottles, juice bottles, milk bottles, and reusable food boxes.
Does not have added mold release helpers.
Meets food safety rules and has NSF 51 certification.

4. Tritan LX101 – For Personal Care Packages:
Made for makeup, perfume bottles, and personal care items.
Has a plant-based mold release helper for easy removal from molds.
It is clear and strong like other Tritan types.
Good for personal care and home items.
Can make containers using injection molding, extrusion blow molding, and injection blow molding.
Compared to EX types, LX101 focuses on making processing easier for everyday consumer goods.

5. Tritan LX150HF / LX151HF – Easy Flowing for Cosmetic Packages:
These are high-flow (HF) Tritan types. They flow about 40–50% easier than standard Tritan when melted.
Made for makeup, perfume, and personal care packages.
Easier flow helps make complex shapes or thin walls. Can speed up production (shorter cycles).
They keep Tritan's toughness, heat resistance, and chemical resistance.
LX151HF is extra clear. LX150HF focuses on high flow.
Used for similar things (fancy makeup bottles, perfume bottles, clear personal care containers).
Can be processed using injection molding, extrusion blow molding, and injection blow molding. Gives designers more freedom.

All these Tritan types are similar. They are copolyesters that do not have Bisphenol A. They resist scratches, are strong, and safe for food contact. The main differences are in their weight, added helpers (like mold release), and how easily they flow when melted. This makes them better for specific uses. For example, baby care types (EX) handle cleaning well. Personal care types (LX) have mold release for easier making. High-flow types (LX150/151HF) flow better for complex shapes.

Even though Tritan types have small differences, how you process them is mostly the same. Here are general tips for extrusion blow molding:

1. Drying: You MUST dry all Tritan types well before processing.
Dry at 88 °C for 4–6 hours. Use dry air (dew point below -35 °C).
Moisture must be below 0.05% (500 parts per million). If not dry enough, the plastic breaks down when melted, making the final product weak (less impact strength).
PETG plastic needs lower drying temperature (around 65 °C). Tritan needs higher heat to get dry because it resists heat better.

2. Melt Temperature: Aim for a melt temperature of about 235–255 °C for extrusion blow molding.
EX401: 240–250 °C.
TX1800: 235–255 °C.
LX types: 235–255 °C.
Lower temperatures in this range make the melted plastic stronger (stops the plastic tube from sagging).
Higher temperatures make the product surface shinier and smoother.
Adjust based on your product.
Note: Tritan melts at a lower temperature than Polycarbonate (PC), which needs 280−300 °C or more. It melts slightly hotter than PETG.

3. Machine Barrel Temperatures: You can set temperatures to slowly decrease from back to front, or keep them flat.
A possible setup: Zone 1 (feed) at 260–275 °C, Zones 2-3 around 270–275 °C, Zone 4 (near head) slightly lower at 265–270 °C, head adapter at 247–260 °C, and die opening at 245–250 °C.
This lets the melt cool slightly at the head, making it thicker and more stable.
Check the actual melt temperature with a probe. Machines differ.
Make sure heat is even. Avoid cold spots that cause problems.

4. Mold Temperature: Use molds cooled with water. Keep mold surface temperature around 15–50 °C.
EX401 suggests 25–45 °C. TX1800 suggests 15–50 °C.
Lower mold temperatures (compared to injection molding) help the plastic tube cool and harden quickly, stopping it from sticking.
Ensure even cooling everywhere in the mold. Areas like bottle necks or handles need good cooling.
If the mold is too hot, parts stick and the cycle takes longer.

5. Blow Air Pressure: Tritan melt is quite thick. Use enough air pressure to push the plastic against the mold walls.
Typical pressure is 0.2–0.4 Megapascals (about 2–4 kg/cm², 25–60 pounds per square inch).
May need higher pressure for large or thick parts.
For tricky shapes or narrow necks, use two steps: low pressure first to gently expand, then high pressure to finish forming.
Set blow time carefully so the plastic tube is ready before blowing hard.

6. Parison Control (Plastic Tube Control): Tritan melt can stretch. Use programming to control the wall thickness of the plastic tube (parison). This stops thick tubes from sagging too much.
For containers with handles, Eastman suggests using pre-pinch or hot-knife methods. These help shape the handle area correctly when the mold closes.
These steps help make sure the final product has even wall thickness.

7. Other Settings:
Use lower extruder screw speeds for Tritan to avoid too much heat from friction.
Cooling time depends on wall thickness. It's usually longer than for High-Density Polyethylene (HDPE) because Tritan cools slower.
Make sure the part cools enough (below 60 °C) before removing it from the mold to prevent warping.

Table: Typical Settings for Some Tritan Types (and Other Plastics)
Table Note: These are typical values. Adjust settings based on your machine and product.

The table shows Tritan needs higher temperatures than HDPE but lower than PC. Drying is very important for Tritan. For cooling, Tritan uses cool molds like PETG and HDPE. PC often needs hotter molds. Tritan melt is thick, so use gentle (low-shear) screws. Machines made for PVC or PC often work well for Tritan. Machines for HDPE might need changes.

Let's compare Tritan with PETG, Polycarbonate (PC), and High-Density Polyethylene (HDPE):

1. Temperature and Heat: Tritan handles heat better than PETG but not as well as PC. Its processing temperature (around 240–250 C) is between PETG (around 210–230 C) and PC (280 C+). HDPE uses the lowest heat (around 170 C). Tritan containers can hold hot liquids (near 100 C) and go in dishwashers. Standard PETG cannot handle this heat well.

2. Drying: Tritan, PETG, and PC soak up water (hygroscopic) and MUST be dried. If not, they weaken when melted. PC is very sensitive to moisture. HDPE does not usually need drying.

3. Melt Flow: Tritan and PETG melt is thick and needs careful handling (low shear). PC melt is also thick but can be processed hotter. HDPE flows easily and can be extruded fast.

4. Machines and Molds: Machines used for PVC or PC often work for Tritan. Machines for fast HDPE processing might need changes (like a different screw) for Tritan. Tritan, PETG, and PC shrink very little (0.5–0.7%), so molds need to be precise. HDPE shrinks a lot more (1.5–3.0%). Some Tritan types have built-in helpers to release from the mold easily.

5. Cooling and Speed: Tritan and PETG take longer to cool than HDPE. PC often takes the longest. So, making HDPE items is fastest, then PETG, then Tritan, and PC is slowest. High-flow Tritan (LX HF) might speed things up a bit.

6. Chemical Resistance (Cracking): Tritan resists cracking from chemicals (like cleaners, oils) much better than PC. PC can crack easily with some chemicals. PETG is also not as good as Tritan against chemicals like alcohols or oils. HDPE resists many chemicals but can soften with oils or crack under stress with some detergents. Tritan bottles are less likely to crack from contents or cleaning.

7. Look and Clearness: Tritan, PETG, and PC can all be made very clear, like glass. HDPE is usually cloudy or solid color. Tritan gives a good mix of easy processing and strong final parts. It is often used instead of PC because it resists chemicals better and has no BPA.

Follow these tips for good results:

1. Dry It Well: This is critical. Wet Tritan makes weak parts. Use a good dryer. Check moisture levels. Keep dried plastic away from air.

2. Use Gentle Processing: Avoid too much heat from friction (shear). Use low-shear screws. Keep temperatures even. If you see brown specks, lower speed or temperature.

3. Clean Machines: Keep machines very clean, especially the die head. Leftover plastic can burn and contaminate clear parts. Use cleaning materials when changing plastics.

4. Cool Molds Properly: Ensure molds cool evenly, especially thick areas. Parts need to be cool enough before removal. Use mold release sprays very carefully only if needed; too much causes problems later (like printing). Keep molds clean.

5. Design Smart: Avoid sharp corners or big changes in thickness in the product design. These spots can crack later. Design the bottom pinch-off area carefully.

6. Not for Pressure: Do not use Tritan for bottles holding high pressure, like fizzy drinks. It is not made for that and could fail.

7. Recycle Scrap: You can reuse leftover Tritan scrap (like trimmed parts), but mix only a small amount (like 20% or less) with new plastic. Dry the scrap too. Clean surfaces before printing or gluing.

8. Safety: Tritan is safe for food. Ensure good airflow in the work area when melting plastic. Recycle Tritan waste.

Tritan's clarity, strength, heat resistance, and chemical resistance make it useful for many blow molded items:

1. Water Bottles: Very common for sports bottles, travel mugs. Tritan is BPA-free, shatterproof, clear, heat-resistant, and does not hold odors. Brands like CamelBak and Nalgene use it.

2. Baby Products: Used for baby bottles, sippy cups. Clear like glass, BPA-free, handles boiling/steam cleaning, strong if dropped. Replaces older plastics like PC.

3. Personal Care Packages: For shampoo, body wash, lotion bottles. Clearer and more resistant to chemicals in the products than PETG. Good for refillable bottles.

4. Makeup and Perfume Containers: Used for clear liners, travel-size sprays. Looks like glass but won't break easily. Resists oils in perfumes.

5. Medical/Lab Items: For hospital wash bottles, sample vials, lab containers needing clarity, chemical resistance, and ability to be sterilized. Safer than glass in labs.

6. Food and Drink Packages: For clear juice pitchers, tea containers, sauce bottles that need to handle heat or washing. Lighter than glass, better heat resistance than PET. Good for reusable containers like returnable milk bottles.

7. Home Goods: For clear storage jars, kitchen canisters, blender jars, coffee mug parts. Stays clear, resists stains and odors.

Tritan offers a good combination of looks, toughness, safety, and heat/chemical resistance for many blow molded hollow products. It helps brands make better, longer-lasting items.