Start With the Use Case, Not the Resin

Material selection usually gets argued on price per kilogram. It should start with the abuse the pack will take: how hot the contents are, whether the buyer needs to see the product, how long the shelf life runs, and whether the brand has made a sustainability commitment. Get those four answers and the shortlist writes itself.

Comparing the Six Common Materials

PP (polypropylene). The workhorse for hot food and takeaway. Good heat resistance, suitable for microwave reheating, tolerant of oils and sauces. Translucent rather than glass-clear. Moderate cost.

PS (polystyrene). Excellent clarity and low cost, which makes it the standard for cold dairy cups, dessert cups and clear lids. Limited heat resistance — it deforms with hot contents.

HIPS (high-impact polystyrene). PS with rubber added for toughness. Opaque, printable and inexpensive, widely used for yogurt cups, trays and dairy formats where clarity is not required.

PVC (polyvinyl chloride). Very clear and rigid, with good forming definition. Still used in some industrial and blister applications, though food-contact use has narrowed considerably in many markets.

PET (polyethylene terephthalate). The clarity benchmark. Strong, recyclable and the default for produce clamshells, salad bowls and premium retail packs. Requires drying before processing.

PLA (polylactic acid). Bio-based and compostable under industrial conditions. Suitable for cold and ambient applications, with a lower heat tolerance than PP. Chosen where the brand needs a demonstrable sustainability story.

The Trade-offs in One Sentence Each

Clarity and recyclability point to PET. Heat and microwave use point to PP. Cost and cold-display clarity point to PS and HIPS. Compostability points to PLA — with a heat ceiling to design around.

Why the Machine Matters as Much as the Resin

Material choice only works if the equipment can process it. Shantou Longsheng Industry Co., Ltd., founded in 1998 in Shantou City, Guangdong Province, builds sheet extruders and thermoforming and cup making machines that process PP, PS, HIPS, PVC, PET, PLA, PE and biodegradable materials. The LSI series PET/PLA single screw sheet extruder includes a drying and crystallisation system precisely because those two materials demand moisture control before forming.

That range means a producer can add PLA to the catalogue without replacing the line. Longsheng holds 25 authorised patents and supports customers with precision molds, installation guidance and operator training.

For more information, visit the official website: https://www.stlongsheng.com