Masterbatch for Plastic Crates and Pallets: Colour That Lasts

A returnable crate or pallet is not a product that gets used once. It is an asset that gets used a thousand times over ten years, stacked in yards, washed, dropped, loaded and left in the sun. The colour in it has to survive all of that, and where the colour codes a logistics system, fading is an operational failure rather than a cosmetic one.

That makes crate and pallet colour a durability specification.

What the product has to survive

Condition	Consequence	What the formulation needs
Years of outdoor storage	Fading, chalking, embrittlement	Strong UV package, lightfast pigments
Repeated washing	Chemical attack, surface wear	Chemical-resistant pigments, no migratory additives
Impact when loaded and dropped	Cracking, especially cold	Impact grade, no agglomerates as stress raisers
Stacking under load	Creep and deformation	Material and design, not colour
Colour-coded sorting	Misreading if shades drift	Tight, repeatable colour
Food or pharma contact	Regulatory failure	Compliant pigment set

The first and the fifth are where colour is directly on the line.

UV is the dominant requirement

Crates and pallets live outdoors. In yards, on docks, in open storage, in transit on open trucks. Nobody specifies them as outdoor products, and they are outdoor products.

Polypropylene, the usual material, is the most UV-sensitive of the commodity polymers. Its tertiary carbon is readily attacked, and unstabilised PP degrades quickly under strong sunlight – first cosmetically, then in impact strength.

The failure sequence matters:

1. Surface chalking and gloss loss 2. Colour fading 3. Loss of impact strength 4. Cracking under a load previously carried without difficulty

Stage 3 is the dangerous one, because it is invisible. A crate that looks slightly tired can shatter when dropped, and a pallet that looks serviceable can fail under load. Neither gave any warning.

So a crate UV package should be specified against retained impact strength after exposure, not against appearance. As with tarpaulin and film, exposure is better expressed as cumulative radiation than as months – see HALS vs UV absorbers.

Colour matters here too. Black crates carry carbon black, which is an excellent UV screen in its own right. Bright colours – the reds, yellows, blues and greens used for coding – have no such protection and depend entirely on the stabiliser package plus the lightfastness of the pigment. The brightest crates need the strongest UV packages, and that is exactly the opposite of how they are usually priced.

Colour coding is a functional specification

In food distribution, pharmaceutical logistics, automotive line-side supply and beverage handling, crate colour identifies contents, ownership, hygiene zone or route.

Two requirements follow:

Shades must be distinguishable from each other, including by workers under poor lighting, at speed, and with the colour vision variation present in any workforce. Colour codes that rely on distinguishing two similar greens fail in practice.

Shades must not drift over years and across production lots. A crate moulded in 2026 has to sit next to one moulded in 2020 and still read as the same code. That is a tolerance requirement across a very long baseline, and it is stricter than most consumer colour work.

This is where Delta E tolerance and lot-to-lot consistency stop being technical niceties. Fixing a physical colour standard with a defined replacement interval, and holding a stated tolerance against it, is what makes a colour-coded fleet work over a decade.

Fading breaks the code as surely as a bad match does. A red crate that has faded to orange after five outdoor years has become a different code. High lightfastness pigments are not a premium here; they are the requirement.

Recycled content

Crates and pallets are among the best applications for recycled polyolefin. They are thick-walled, non-food in many cases, and mechanically forgiving compared with film or pressure pipe. Many are already made with substantial recycled content, and EPR obligations push further in that direction.

What that does to colour:

The base is grey or brown and it moves between lots. Achieving a bright, consistent code colour on variable recyclate requires more pigment, more opacity and a formulation designed against the actual feedstock. See masterbatch for recycled and PCR plastic and our recycling masterbatches.

Light and pastel shades become impractical. There is a limit to how far a grey substrate can be lightened before the titanium dioxide loading is changing the mechanics. If a colour code system is being designed for a recycled-content fleet, design the palette around what the material can hold – dark and saturated codes rather than pastels.

Closed-loop recycling of your own crates is the best case, because the feedstock is your own known material in your own known colours. A fleet returned, ground and remoulded gives far more predictable colour than open-market recyclate.

Food contact and pharma

Crates for fresh produce, meat, dairy, bakery and pharmaceutical distribution carry regulatory requirements on the material and on the colourant.

The pigment set must be compliant for food contact at the loading used, and washing regimes mean migratory additives are the wrong choice – a migratory antistat or slip additive will be stripped by repeated washing and, worse, is available to migrate into contact media. See antistatic masterbatch on why permanent systems are correct for washed, reused articles.

Related: pharma, household, what is masterbatch.

Practical formulation points

Dispersion quality has mechanical consequences. A crate is an impact product, and a pigment agglomerate is a stress concentration. Poor dispersion shows first as a cosmetic speck and later as a crack that started there.

Watch the dosage on high-opacity colours. Bright, opaque colours on a dark recyclate base need heavy pigment and TiO2 loading, and at that level the masterbatch is a real fraction of the compound. Its carrier and flow behaviour matter – see melt flow index explained.

Consider whether the colour needs to be through-thickness. It does. A crate is abraded, scuffed and impacted throughout its life, and any surface-only colour is gone within months.

Ask about marking and printing. Crates are usually hot-stamped, embossed or labelled with ownership marks. Additives that migrate to the surface interfere with print and label adhesion.

Specification checklist

– Polymer and grade, with impact requirement – Recycled content percentage and feedstock source – UV requirement as retained impact strength after defined exposure, plus region – Colour standard per code, with tolerance and a standard replacement interval – Lightfastness requirement, stated on the blue wool scale – Food contact or pharma requirements – Washing regime – chemistry, temperature, frequency – Printing, labelling or hot stamping requirements

Talk to us

Life Color Pigments & Masterbatches supplies colour, black and additive masterbatches for crate, pallet and material handling mouldings, under ISO 9001:2015.

If you run a colour-coded fleet, send us your code standards, your recycled content and your outdoor exposure and we will formulate for shade stability across lots and across years – which is the property that actually matters in this application.

Related: packaging, household, agriculture, furniture.

FAQs

Why do plastic crates fade and crack outdoors? Because polypropylene is the most UV-sensitive commodity polymer and crates spend years in open yards. Degradation shows as chalking and fading first, then as loss of impact strength, which is the dangerous stage because it is invisible until a crate shatters when dropped.

How should UV performance for crates be specified? As retained impact strength after a defined exposure, with exposure expressed as cumulative solar radiation and the region of use stated. Appearance is a poor proxy, because impact strength is lost while a crate still looks serviceable.

Do bright coloured crates need more UV protection than black? Yes. Carbon black in a black crate is an excellent ultraviolet screen in its own right. Bright coding colours have no such protection and depend entirely on the stabiliser package and the lightfastness of the pigment.

How tight should colour tolerance be for colour-coded crates? Tight enough that a crate moulded ten years apart still reads as the same code, which is a stricter requirement than most consumer colour work. Fix a physical standard with a replacement interval and hold a stated Delta E tolerance against it.

Can crates be made with recycled plastic? Yes, and they are among the best applications for it – thick-walled, mechanically forgiving and often non-food. The consequence is that the base colour is grey or brown and varies between lots, so bright codes need more pigment and pastel shades become impractical.

Are migratory antistatic or slip additives suitable for reusable crates? No. Repeated washing strips a migratory additive from the surface, and in food contact applications it is available to migrate into contact media. Use permanent inherently dissipative systems where a static requirement exists.

Does pigment dispersion affect crate strength? Yes. A crate is an impact product and an undispersed pigment agglomerate acts as a stress concentration. Poor dispersion appears first as a cosmetic speck and later as the origin of a crack.

Should crate colour go all the way through the wall? Yes. Crates are scuffed, abraded and impacted throughout their service life, so any surface-only colour treatment is worn away within months. Colour must be in the bulk material.