A tray can pass every test in the product-development kitchen and still stain through at a street-food stall, because the stall holds nuggets and sauce for twenty minutes while the kitchen test lasted five. The coating is the part of a printed paper tray that decides that outcome, and unlike a closed box, a tray has an exposed rim, crease-heavy corners and nothing covering the food. In short: dry food can go on uncoated board, fried food needs at least grease resistance, and sauced or long-held food needs PE or a well-tested dispersion layer. The sections below cover where tray coatings fail, how to test them and how single-use plastic rules treat each option. The underlying chemistry is in barrier coatings for paper packaging; the product overview is the hub on custom printed paper food trays.
Which paper food tray coating suits which food?
Dry snacks and baked goods can go on uncoated or fluorine-free grease-resistant board, fried food usually needs at least a light barrier, and saucy or long-held food needs PE or a well-tested dispersion layer. The deciding factors are the fat and water content, the holding time and the temperature.
| Food | Holding time | Suggested coating | Comment |
|---|---|---|---|
| Biscuits, pastries, dry snacks, chips | Short or long | Uncoated board | No barrier needed unless the food is oily |
| Fried snacks (nuggets, tenders), pizza slice | Up to roughly 10-15 minutes | Fluorine-free grease-resistant board or light dispersion | Open top lets steam out; grease is the main risk |
| Hot dogs, bratwurst in a roll | 5-10 minutes | Grease-resistant or dispersion inside | Mustard and sauce are the stress points |
| Loaded fries, nachos with sauce | 5-15 minutes | PE or well-tested dispersion | Sauce reaches the base quickly |
| Currywurst, kapsalon, kebab with sauce | 10-20 minutes | PE, or a closed container with a barrier instead | Heavy liquid load |
| Fresh, wet food (salad, fruit, cold) | Variable | PE or dispersion, or a different container | Water, not grease, is the issue; trays are rarely ideal |
| Foods that will be reheated | Variable | PE-coated or uncoated, tested at reheat conditions | Heat resistance differs by coating |
A two-specification approach often works across a menu: one grease-resistant tray for dry-fried items and one PE or dispersion tray for sauced items. How to consolidate formats is covered in how to reduce takeaway packaging SKUs across a menu. For hot, wet and saucy food in particular, a closed container is often the better format; see takeaway boxes for hot, wet and saucy food.
How do PE, dispersion, PLA and uncoated trays compare?
PE gives the strongest water and grease resistance and allows heat-sealed corners; dispersion barriers use less polymer and usually repulp more easily but can weaken at creases; PLA performs like PE for many uses but suits a compostability claim only under strict conditions; uncoated grease-resistant board has no plastic layer and limited liquid resistance.
| Property | PE extrusion | Aqueous dispersion | PLA coating | Uncoated, fluorine-free grease-resistant |
|---|---|---|---|---|
| Typical coat weight | Typically in the region of 12-20 g/m2 | Applied thinner than PE, grade-dependent | Extrusion-coated at weights similar to PE | None |
| Grease resistance | Very good | Good to very good, grade-dependent | Good to very good | Moderate; depends on the base board treatment |
| Water and sauce resistance | Very good | Moderate to good | Good | Low |
| Behaviour at folds and corners | Generally holds up well | Can crack at sharp creases; test the actual fold | Generally holds up well | Not applicable |
| Heat sealing of corners | Yes | Some grades | Yes | No (glued or locked) |
| Typical heat limit | Softens at oven temperatures; suitable for hot food and short microwave reheating | Grade-dependent; check hot-fill | Lower than PE for standard grades | Good for hot food; limited by grease and moisture |
| Treated as plastic under EU SUP guidelines | Yes | Depends on the polymer chemistry; confirm in writing | Yes | No |
| Recyclability | Repulpable where mills can separate the film | Typically designed for repulping; confirm with a test report | Layer rejects; contaminant in plastic streams | Generally recoverable as paper if not heavily soiled |
Coating can be on the food side only (the usual case for trays), on both sides, or on the printed face with the print beneath it. Coating only the inside keeps the outside free for print and tactile finishes. Wax-coated trays remain in use for cold or dry foods in some markets but are not suited to hot fatty food and are not discussed further here.
Where do coatings fail on trays?
The three most common failure points on an open tray are the cut edge, the creased corner and the glued seam. Surface barrier performance in the laboratory can look excellent while the tray leaks or stains at one of these.
- Cut edges. Die-cutting leaves raw fibre along the whole rim and at every fold. Liquid wicks from the exposed edge into the board even when the face is coated. Good design keeps sauce below the lowest exposed edge, rolls or hems the rim, or uses a tray where edges face outwards and above the liquid line.
- Creased corners. Folding a coated board stretches and compresses the coating along each crease. PE tolerates this well; dispersion layers vary and may micro-crack at tight radii, so creases should be tested on the actual dieline and board.
- Glued seams. Adhesives bond to PE less readily than to bare board, so the glue area is often left uncoated, or the corners are heat-sealed in a PE tray. A leak at a seam is an assembly issue and not a coating issue, so ask how corners are joined.
- Heat and steam. Hot food in an open tray loses steam upward rather than into the coating, but a tray held under a heat lamp is exposed to heat for far longer than food in a closed box. PLA in particular needs to be checked for the temperature it will meet.
- Grease rub-off. Print can lift if varnish or ink is not compatible with the barrier or the food; test the printed, coated tray with the real food.
Buyers can reduce risk by specifying the food, the holding time and the temperature, and by asking for a sample made on the actual dieline rather than a flat board test.
How should a tray coating be tested?
Test the finished tray with real food for the real holding time, and supplement that with standard board tests for grease and water. Laboratory figures are a starting point, and the pass criteria should be agreed with the supplier at technical review.
- KIT test for grease resistance, which rates board by its resistance to a series of oil-and-solvent mixtures. See KIT test and grease resistance.
- Cobb test for water absorption, reported as grams of water absorbed per square metre over a set time (for example 60 seconds); lower is better.
- Edge wicking test: fill with coloured sauce and measure how far the liquid travels into the cut edge after a set time.
- Fold test: crease and flex the board along the tray folds, then check the coating at the crease with a dye or oil test.
- Hold test: fill with the hottest, greasiest, sauciest menu item and hold for the longest realistic time, ideally on a warm counter.
- Reheat test, if reheating is part of use: microwave or oven as the operator would.
Whether a tray is microwave-safe is a product-specific question. PE-coated and uncoated board are commonly reheated for short cycles, but metallic inks, foil elements and certain adhesives are not suitable, and oven use is not suited to polymer-coated paper. Confirm the intended reheating method with the supplier so the declaration of compliance covers it.
Are PE, dispersion and PLA coated trays single-use plastic?
Under the EU Single-Use Plastics Directive (EU) 2019/904 and the Commission guidelines 2021/C 216/01, paper or board with a plastic lining or coating is treated as a single-use plastic product, so a PE-coated tray is a single-use plastic food container. PLA is still plastic. Dispersion coatings are not automatically outside scope: classification depends on the polymer chemistry, and the guidelines set no de minimis threshold.
The practical consequences differ by market:
- EU: food containers in SUP scope carry extended producer responsibility costs and national consumption-reduction measures; they do not need the printed "plastic in product" marking that applies to beverage cups. Plastic plates, including plastic-coated paper plates, are banned; the Commission guidelines treat a lidless, predominantly flat dish used to serve or eat from as a plate, so a very flat coated tray is a borderline case. See paper vs plastic vs aluminium food trays.
- Germany: single-use plastic food packaging triggers the reusable-offer duty (Mehrwegangebotspflicht) for takeaway outlets and the single-use plastic fund (Einwegkunststofffonds) levy by weight. See Germany and Austria.
- Netherlands: partly plastic single-use cups and containers, including PE-lined board, may not be used for on-site consumption since 1 January 2024. See Netherlands packaging compliance.
- England: plastic-coated paper plates, trays and bowls supplied empty are within the ban from 1 October 2023; trays filled at the point of sale are treated as packaging and exempt. See UK packaging regulations.
- PPWR (Regulation (EU) 2025/40): from 1 January 2030, Annex V restricts single-use plastic packaging for food filled and consumed on HORECA premises; the Commission's non-binding notice C(2026) 3702 of 5 June 2026 treats paper-based packaging with 5 % or more plastic as covered. PFAS limits apply from 12 August 2026. See PPWR explained for foodservice buyers.
Obligations depend on the company's role and should be confirmed with the competent authority or compliance scheme. If a supplier calls a coating "plastic-free", ask which polymer it is and for the supplier's regulatory position in writing.
What about "plastic-free", "compostable" and PFAS claims on trays?
A claim is only as good as the document behind it. "Plastic-free" needs a polymer identification and a regulatory position; "compostable" needs a certificate for the finished construction; "grease-resistant" must be achieved without PFAS where limits apply.
- "Plastic-free": see the preceding section. Water-based does not mean non-plastic.
- "Compostable": EN 13432 certifies industrial compostability in specific facilities and is not a home-compost claim. The PPWR (Article 9) limits the packaging that must be compostable to a short list (such as tea bags and fruit stickers); other packaging should be recyclable. See recyclable vs compostable packaging.
- Generic environmental claims: the Empowering Consumers Directive (EU) 2024/825 applies from 27 September 2026 and bans generic claims such as "eco-friendly" or "biodegradable" without recognised excellent environmental performance; in the UK the CMA's Green Claims Code and the DMCC Act 2024 apply.
- PFAS: fluorinated grease-proofing agents are restricted in food-contact packaging in the EU from 12 August 2026 and in a growing number of US states. Fluorine-free grease resistance should be documented. See PFAS-free food packaging.
- Recyclability: PPWR recyclability grades apply from 2030 and the design criteria are still being finalised. See PPWR recyclability grades.
Documents to ask for are listed in food-contact packaging compliance in the EU, UK and US.
Specification checklist for tray coatings
- Food, fat and water content, sauce, temperature at filling.
- Holding time to eating, and whether the tray is reheated or held under a lamp.
- Coating option wanted (uncoated, fluorine-free grease-resistant, PE, dispersion, PLA) or "supplier to propose".
- Coated on the inside only or both sides.
- Dieline and corner construction (glued, locked, heat-sealed).
- Markets of sale, for SUP and PFAS statements.
- Test expectations (KIT, Cobb, hold test) and the sample to be approved.
Send the specification, with the food and holding time, through our contact page. Board, print and construction are covered on the paper food tray hub, and tray size in paper food tray sizes.
The same barrier options appear on cups; compare them in paper cup linings: PE vs aqueous dispersion vs PLA.