Thermoforming Material Selection Guide — Shirley K’s
Choosing the right material is one of the most important steps in any thermoforming project. The resin you select drives durability, food-contact suitability, temperature performance, and cost. This guide explains the materials Shirley K’s runs and how we match them to common applications.
MATERIALS WE RUN
- HMW-HDPE (High Molecular Weight High-Density Polyethylene): our primary material for food handling and material handling totes and lugs. Tough, impact-resistant, suitable for food contact applications, and 100% recyclable.
- HIPS and PETG: used for our organizational and school storage trays, where a wide range of sizes and colors matters.
- ABS, Kydex, Acrylic, PC (polycarbonate), and HDPE: used for custom thermoforming jobs, selected to fit each part’s strength, finish, and application requirements.
HOW TO CHOOSE
- Food contact: HMW-HDPE is suitable for food contact applications — confirm requirements against the product specification.
- Impact and durability: HMW-HDPE offers strong impact resistance for demanding, repeated-use environments.
- Temperature: HMW-HDPE SKUs perform across a range of -76 °F to 180 °F.
- Gauge: for heavy-gauge custom work we form material from .080″ to .450″.
- Appearance and detail: HIPS, PETG, ABS, acrylic, and polycarbonate suit parts where finish, clarity, or specific mechanical properties are important.
Not sure which material fits your part? Send us your drawing, volume, and application and we’ll recommend an option.
GET STARTED
Request a quote or start a custom project:
Call: (740) 868-8140 Email: orders@shirleyks.com
Engineered for Extreme Duty
High-Molecular-Weight HDPE (HMW-HDPE) is Shirley K’s workhorse material for demanding service. Here’s how it behaves where standard injection-molded HDPE struggles.
Stays tough in the cold
Long, entangled polymer chains keep the material ductile in freezer and deep-cold service. A dropped tote dents instead of shattering — contents stay contained.
High impact resistance
Biaxial molecular orientation and near-zero residual stress spread impact across the whole part, not along one weak axis.
Resists chemical stress cracking
High ESCR stands up to sanitizers, animal fats, oils, and repeated washdowns — without the spider-web surface cracks common to injection-molded totes.
Safe, ductile failure
Instead of sudden brittle shattering (and sharp shards in food), HMW-HDPE flexes and dents while keeping its shape and containment — a higher safety margin for cold-chain and food.
| Property | Shirley K’s Thermoformed (HMW-HDPE) | Standard Injection-Molded HDPE |
|---|---|---|
| Molecular structure | Long, entangled chains — biaxial reinforcement | Shorter chains — primarily one direction |
| Residual stress | Near zero (low-pressure forming) | High (locked in by rapid cooling) |
| Cold-impact behavior | Ductile — flexes, dents, recovers | Brittle — sudden cracking near/below freezing |
| Chemical stress-crack resistance | Excellent ESCR | Moderate — accelerated by cold + chemicals |
| Failure mode | Visible denting, stays contained | Sudden shatter — possible shards |
Evaluated against recognized ASTM methods (D256 Izod impact, D746 brittleness temperature, D1693 / F2136 stress-crack resistance). Resin technical data sheets available on request — request specs or a quote.