From Tray to Table: Picking the Right Plastic for Food-Grade Thermoforming
When you’re designing for food packaging or equipment, picking the right plastic isn’t just about cost or availability. It’s about how it performs under heat, chemicals, impact, and time—and whether it’ll survive the real world of food manufacturing, processing, and cleaning.
Thermoforming is a popular way to shape food-safe plastics into trays, bins, containers, lids, and more. But not all plastics are cut out for the job. Some can handle the dishwasher. Others melt at the first sign of heat. Some are crystal-clear but scratch if you breathe on them wrong. The trick is knowing which material fits your needs—and where the trade-offs lie.
Let’s break down the four major players in food-grade thermoforming plastics: HDPE, PP, HIPS, and PETG.
HDPE: A Chemical-Resistant Workhorse
High-Density Polyethylene (HDPE) is the tank of food-safe plastics. You’ll see it in cutting boards, bulk storage bins, milk jugs, and industrial food containers. It’s incredibly resistant to moisture, acids, detergents, and impact.
Where it shines:
- Doesn’t absorb moisture
- Takes a beating without cracking
- Handles harsh chemical cleaners like a pro
Where it struggles:
- Doesn’t like heat—warp city in high-temp wash cycles
- Doesn’t form as easily as others due to shrinkage
- Won’t bond well with adhesives or inks
In short: Great for rugged environments, but don’t ask it to go in the microwave or through an autoclave.
PP: The Heat-Loving All-Rounder
Polypropylene (PP) is a favorite for microwavable containers, hinged lids, yogurt cups, and beverage caps. It’s strong, flexible, and has exceptional heat and fatigue resistance.
Where it shines:
- Survives steam cleaning and autoclaves
- Excellent chemical resistance
- Repeated flexing? No problem (think living hinges)
Where it struggles:
- Can be brittle in cold temps
- A bit harder to thermoform—needs tight temp control
- Not the most rigid of the bunch
If your part needs to be heated, cleaned often, or flexed repeatedly, PP is a strong bet.
HIPS: The Budget Hero for Disposable Packaging
High-Impact Polystyrene (HIPS) is the cheapest and easiest to form, which is why it’s everywhere in takeout trays, bakery packaging, and throwaway cups. It forms fast, prints beautifully, and makes packaging look great—at least for a short time.
Where it shines:
- Super low-cost
- Extremely easy to thermoform
- Great for printing, branding, and smooth finishes
Where it struggles:
- Poor resistance to heat and chemicals
- Low impact strength
- Definitely not reusable or sterilization-friendly
Use HIPS when you need a lot of parts, fast and cheap, and nobody’s expecting them to last.
PETG: Clear, Tough, and a Bit Fussy
Polyethylene Terephthalate Glycol (PETG) is what you reach for when you want a product to look sharp and stay tough. You’ll find it in clear clamshells, medical food trays, and retail food packaging.
Where it shines:
- Crystal clear and visually appealing
- Great impact resistance for rigid packaging
- Easy to form with excellent detail retention
Where it struggles:
- Scratches easily
- Doesn’t like strong solvents or high heat
- Can deform under aggressive cleaning
PETG is perfect when presentation and toughness matter—but you’ll need to baby it a bit during cleaning.
Sterilization & Cleaning: Who Can Take the Heat?
Cleaning is a dealbreaker in food environments. Some materials can handle steam and pressure. Others can barely survive soap and water. Here’s how they compare:
Chemical cleaners:
- HDPE and PP thrive here—bring on the detergents and sanitizers.
- PETG prefers mild soaps.
- HIPS wants only gentle treatment.
High heat cleaning (dishwasher/autoclave):
- PP is your only safe bet. It handles steam and high-temp cycles easily.
- HDPE is OK for warm water, but not boiling.
- PETG and HIPS will warp or degrade.
Gamma sterilization:
- HDPE, PP, and PETG all handle radiation reasonably well.
- HIPS? Not so much. It turns brittle.
So Which One Should You Use?
There’s no one-size-fits-all winner here. It all depends on what your part needs to do.
Need something microwavable or reusable? Go with PP.
Designing a rugged bin or chemical-resistant tray? HDPE is solid.
Cranking out high-volume disposable trays? Use HIPS and keep it simple.
Need crystal-clear, premium retail packaging? Call in PETG.
The trick is understanding the trade-offs—and that’s where having the right partner helps.
Let RapidMade Help You Get It Right
At RapidMade, we specialize in thermoforming and food-safe plastics, helping engineers and designers choose the right material for performance, safety, and cost-efficiency. Whether you’re prototyping a new package or scaling up a production line, we bring technical expertise and real-world manufacturing know-how to every project.
Ready to make your next thermoforming job cleaner, tougher, and smarter?
Check out our services at rapidmade.com or reach out to us at info@rapidmade.com.
