Material follows use
A container material is chosen for what the food or the stored item will do to it: heat, oil, acidity, freezing, reheating, washing, sunlight on a shelf, or nothing at all. The rule the desk applies across the range is simple. Hot food and reheating call for PP. Cold display and fruit call for clear PET. PVC belongs only in non-heated packaging and storage. Paperboard carries bakery, gift and click-lock boxes. Storage and organizer lines use PP, PS, HDPE, ABS, acrylic or copolyester according to the part. Every part is named with its material: base, lid, insert, gasket and window.
The materials side by side
| Material | Resin code | Typical parts | Heat and use notes |
|---|---|---|---|
| PP, polypropylene | 5 | Takeout boxes, soup cups, bowls, meal prep, fridge bins, collapsible boxes | Hot food; microwave use per supplier marking |
| PET | 1 | Fruit clamshells, cold cups and bowls, clear lids, fridge bins | Cold use only |
| PVC | 3 | Clear folding boxes, gift box windows, soft organizer cases | Non-heated packaging and storage only |
| PS | 6 | Clear drawer organizers, desk trays | Not for hot food in this range |
| HDPE | 2 | Pet food bins | Dry storage |
| Copolyester, acrylic, ABS | 7 | Vacuum containers, organizers, rigid shoe boxes | Per supplier specification |
| Starch-PP blend | Per declaration | Bowls, boxes, divided meal boxes | Described as a blend, no compostable claim without certification |
| Paperboard | Not a resin | Bakery, gift, pizza and click-lock boxes | PFAS rules apply in several US states |
PP, the hot food material
Polypropylene keeps its shape with hot food better than the other common container plastics, is light, resists oil and most food acids, and can be thermoformed or injection molded. FDA 21 CFR 177.1520 covers olefin polymers including PP and gives a melting point range of 160-180 degrees C as part of its specifications. That is not a use temperature: a container's working range depends on wall section, design and the conditions of use, so it is stated per supplier marking and checked on the sample. One partner plant's literature describes its cup PP as tolerating -10 to 120 degrees C; the desk treats that as a supplier statement until it is tested. Soup cups from a Guangdong catalog carry the code 5 and a microwave marking molded in the base. See PP food containers.
PET, the clarity material
PET gives the clearest parts and a stiff, crisp feel, which is why it is used for supermarket fruit and salad boxes, cold drink cups and clear lids. It is not used for hot food or reheating in this range. Where a fruit box will be reheated or reused, a clear PP version is offered instead; the trade-off is a little haze. A set combining a PP base with a PET lid is labelled for cold use.
Where PVC belongs
PVC has a place in packaging, but not in a hot food container. Consumer and industry guidance points out that migration risk from PVC rises with heating, and reputable food packaging plants avoid it for microwave containers. In this range PVC appears only where nothing is heated and the part does not hold hot food: clear folding boxes, windows and lids on paper gift boxes, and soft clear cases for cosmetics and small items. The partner plant catalogs behind this site list no food container made of PVC at all. The full argument is in the note where PVC belongs in packaging.
Starch blends and paperboard
Containers sold as corn starch are usually starch blended with PP or another polymer; the partner plant catalog lists them under its PP thermoforming range, and the blend ratio is confirmed per project. They are described as starch-based with lower plastic content, and biodegradable or compostable wording is used only where the product holds a named EN 13432 or ASTM D6400 certification, qualified as the FTC Green Guides require. Paper boxes use white card, kraft and white card with a foil lining; for the US, several states restrict intentionally added PFAS in plant fibre food packaging, with California's AB 1200 in force since 1 January 2023. See starch-based food containers and the sustainable packaging guide.
How the material is specified
The specification names the material of each part, the resin grade or supplier declaration it relies on, any color masterbatch, and the market rules the documents must cover. Color and additives are part of the material: a black base uses a different masterbatch from a clear one, and the declaration has to cover the finished part, not only the base resin. The container material guide applies these rules line by line, and the desk confirms material and documents in writing for each program; quantities are on MOQ and lead time.