Start with the service condition, not the resin
Most material arguments start in the wrong place — with the name of a plastic instead of the job the pack has to do. A container is only as good as its match to the food, the temperature and the time it spends in the customer's hands. Before you compare PP with PET, answer six questions:
- What is the filling temperature — ambient, hot-fill above 80 °C, or portioned cold from a chiller?
- Will the customer reheat the food in the container, in a microwave?
- How much fat, oil, acid or alcohol does the dish contain, and how long does it sit in the pack?
- Does the pack go into a freezer or a blast chiller?
- Does the product need to be seen? Clear packs sell different categories from opaque ones.
- Will the pack be printed, sleeved or labelled — and does the surface take ink or adhesive cleanly?
Those answers decide the material, the wall weight, and usually which existing mould is closest to the job. They also decide which questions you should be asking your supplier, because a price without a material grade, a gram weight and a temperature range is not a specification.
The four materials side by side
| Property | PP | PET | PS | Paperboard (PE or PLA lined) |
|---|---|---|---|---|
| Typical service | Hot fill, delivery, microwave reheating | Cold and chilled service, display | Rigid, room-temperature and cold service | Hot or cold dry and semi-liquid food |
| Heat behaviour | Moulded for microwave use; the 2,000 ml round bowl is rated microwave safe to 120 °C | Loses shape and clarity above roughly 60–70 °C; not a microwave format | Not for hot oil or long hot contact; can craze | Short-contact hot service is fine when the lining is specified — the coating decides, not the board |
| Clarity | Translucent to opaque; colour matching and embossing available | Glass-clear | Clear and rigid | Opaque, fully printable |
| Grease and oil | Good resistance | Good resistance | Fair — hot fat dulls and crazes the surface over time | Depends on the lining; grease-resistant board options available |
| Decoration | Colour-matched bodies, printed or embossed lids | Sleeves and labels rather than direct print | Colour options, limited print area | Full-colour print, typically from 50,000 pcs |
| In our catalogue | Containers from 280 ml to 3,550 ml, round lids 120–185 mm, portion cups | Oyster boxes, wide catering lids (RO series, DB150) | Cutlery moulds from 115 mm to 178 mm | Food containers 500–1,300 ml; cups 4–16 oz on 300 gsm–320 gsm board |
Weight per piece is a specification, not a detail
The number that moves both your unit price and your freight bill is grams per piece. In our catalogue a 300 ml round container weighs 13.5 g, a 500 ml round container 17 g, a 700 ml round container 22.6 g, a 750 ml rectangular container 35.5 g, and the 3,550 ml catering bowl 30.5 g. Two containers of the same capacity can differ by half in resin weight, and that difference is either wall strength or cost — sometimes both.
So ask for the gram weight in writing, then measure ten pieces from the production sample and put the average into your specification sheet. A supplier who cannot state grams per piece is not controlling the thing you are paying for. A thinner wall is not automatically worse: it is a trade-off against rigidity, lid fit and how the pack behaves when it is stacked four high in a delivery bag.
Match the lid to the material
Bodies and lids are usually quoted together, but they do not have to be the same resin. In our range the round lids from 120 mm to 185 mm are moulded in PP, while the wide catering lids — RO-16, RO-24, RO-32, RO-48 — and the 150 mm DB150 are PET. PP is the lid for packs that are reheated or hold hot sauce; PET is the lid when the customer needs to see the food, which is why cold display and catering trays usually take a clear PET cover.
Lid weight and packing matter as much as the body. The 120 mm PP lid is 5.1 g and packs 500 to a carton; the 185 mm lid is 5.3 g and packs 300 to a carton. When the lid is a different resin from the body, say so on the specification sheet and ask for the fitted pair to be tested together — lid fit is one of the checks we run on every production batch, because a body that fits at 20 °C can behave differently after a hot fill.
Paperboard: decide the lining first
Paperboard food containers run from 500 ml to 1,300 ml in kraft or white, with grease-resistant options and either a PE or a PLA lining. Paper cups are built on 300 gsm–320 gsm board, single-layer or double-wall, from 4 oz to 16 oz, with the same choice of lining. The board carries the structure and the print; the lining decides what the pack can hold.
Two practical rules. First, specify the lining and the board weight in grams per square metre on the PO — “paper cup” is not a specification. Second, do not print a reheating instruction on a board pack unless the lining is specified for microwave use; the label is a promise, and the wrong promise is how importers end up with complaints.
How to word a recyclability claim
Recyclability is the fastest-moving part of packaging labelling, and the easiest place to make a claim you cannot support. Four rules keep you out of trouble:
- Claims belong to the market, not the material. What counts is whether the pack is collected and actually reprocessed where the consumer throws it away. PP and PET are collected in rigid plastic streams in many markets; PS is accepted in fewer kerbside programmes; paperboard with a PE lining is often rejected by paper mills where the coating cannot be separated; a PLA-lined board behaves differently again.
- Check the rules before you print. Several markets regulate recyclability claims on packaging — how the pack must be labelled, and what evidence the brand owner has to hold. The obligation usually sits with the importer or the brand, not the converter.
- Keep the wording measurable. “Made of PP” is a fact you can prove. “100% recyclable” is a claim you have to defend with local collection data. Where you are unsure, describe the material and let the consumer read the label.
- Ask us for the composition. We supply the material breakdown you need to write your own label text, and we do not publish recyclability claims for your market.
Compliance is a document chain, not a slogan
We hold a raw-material grade declaration for every resin and board we buy, and in-house QC records for every production batch. Where your market requires independent test reports — migration, heavy metals, or the specific parameters your regulator lists — third-party laboratory testing can be arranged on request against your specification. What we cannot do is decide compliance for you: the requirement sits with the importer, so write the document list into the purchase order before the deposit and keep the reports with the shipping file.
Five selection rules that save a project
- Hot and reheated: PP.
- Cold and clear: PET.
- Rigid, cold, cutlery or a portion cup: PS.
- Hot, dry, printable, or paper is the brand: lined paperboard.
- Mixed menu: pick one material for the hot line and one for the cold line, and keep the lid diameters inside those two families so one lid SKU covers several sizes.
Send us the menu and the service temperature and we will tell you which of the moulds in our catalogue is closest — and whether the honest answer is that you need a new one.