Secondary packaging for chemicals is designed against a primary container failure, not against normal handling. The question is what happens to the rest of the case or pallet when one bottle or drum lets go - contained, or spread.
- Designing for the failure you expect
- Material compatibility works both ways
- Weight, density and stacking
- Identification that survives
- Regulated carriage
- Small volumes and laboratory despatch
- Returns and part-used stock
- What to send us
- A first step for chemical manufacturers
- The short version
- Frequently asked questions
Designing for the failure you expect
Most packaging is designed so that nothing goes wrong. Chemical secondary packaging is designed on the assumption that something eventually will, because the consequence of a leak reaching the rest of a pallet is disproportionate to the value of the one container that failed.
That changes the test. The useful question is not whether the pack protects the bottle, but what the case does when one bottle lets go - whether it contains, absorbs and identifies, or distributes the problem across everything around it.
Material compatibility works both ways
A plastic or an adhesive that performs perfectly in general use can be exactly wrong next to a particular product. The failure is usually slow - a liner that degrades, an adhesive that softens - and slow failures rarely get attributed to the packaging.
- Check the liner and any film against the contents, not just the outer.
- Adhesives on tape and labels are in contact with the pack atmosphere too - see Packing Tape: Grades, Widths and When Each Works.
- Absorbent materials have to be compatible as well as absorbent.
- Closures and seals are frequently the first thing to degrade.
- Where contents change formulation, revisit the packaging rather than assuming it carries over.
Weight, density and stacking
Dense liquids sit low in a case, which feels stable and is not the same as being stackable. The bottom layer still carries everything above it, and the compression performance of the case is what decides whether it holds.
| Element | Why |
|---|---|
| Board base | Spreads load onto the pallet rather than into case corners |
| Fitted dividers | Stops unit-to-unit impact, which is where containers fail |
| Controlled stack height | Compression is cumulative through the stack |
| Corner protection | Carries compression outside the cases - see Corner Boards, Edge Protection and Pallet Stability |
| Column stacking | Carries considerably more than interlocking |
| Strapping | Ties the load to the pallet rather than around it |
What dense liquid loads need.
Identification that survives
Hazard identification and content labelling have to be durable and in a known position. A label that has degraded or that requires the pack to be opened to read defeats the purpose, and it creates a handling problem rather than merely an administrative one.
Position should be fixed in the specification rather than left to despatch, so that handling at every point is consistent.
Regulated carriage
Where a despatch falls under carriage regulations, that has to be established before anything else is decided - it changes the specification, the labelling and sometimes the carrier. It is not a detail to confirm after a pack has been designed.
We specify and supply transit and secondary packaging; where regulated carriage applies, the requirement needs stating up front so the specification is written to it.
Small volumes and laboratory despatch
Small-volume chemical despatch has the same containment logic at a different scale, plus an identification problem: mixed despatches of many small items are easy to get wrong and hard to check.
Compartmented inserts labelled per line solve both at once - the pack becomes self-checking because a missing or wrong item is visible rather than counted. See Foam Inserts: When a Fitted Pocket Pays for Itself.
Returns and part-used stock
Part-used containers and returns are a normal part of chemical supply and are frequently unspecified. The return leg has different contents, a different packer and often a different containment requirement from the outbound journey.
A defined return pack removes the assumption that whoever is sending it back knows how - see returns management.
What to send us
The product and its container, what it is incompatible with, whether regulated carriage applies, how it is palletised, and anything that has leaked or failed. A photograph of a failed pallet is worth a great deal here, because it shows how far the failure travelled.
See industrial packaging and protective packaging.
A first step for chemical manufacturers
The test worth running is not whether the pack protects the container, but what the pack does when a container fails.
- Work out what happens to the rest of a case if one unit leaks. If the answer is 'all of it', the secondary pack is not doing its job.
- Check absorbent quantity against the volume of a single container, not a token amount.
- Confirm material compatibility covers liners, adhesives and labels, not just the outer.
- Check hazard labelling is readable after the journey, not just at despatch.
- Establish whether a defined return pack exists for part-used stock.
The short version
- Design the secondary pack against a primary container failure.
- Material compatibility covers liners, adhesives and absorbents, not just the outer.
- Dense liquid low in a case does not make the case stackable.
- Hazard identification must be durable and in a fixed position.
- Regulated carriage changes the specification before anything else is decided.
Frequently asked questions
What should chemical secondary packaging do?
Contain a primary container failure, identify the contents durably, and survive the journey. The test is what happens to the rest of the case when one container lets go.
Can you supply packaging for regulated goods?
We specify and supply transit and secondary packaging. Where carriage regulations apply, that must be stated up front because it changes the specification and the labelling before anything else is decided.
How should drums and dense liquids be palletised?
Board base to spread load, controlled stack height, corner protection and strapping that ties the load to the pallet. Weight low in a case is not the same as a stackable case.
What about material compatibility?
It covers liners, films, adhesives and absorbents as well as the outer. These failures are slow and are rarely attributed to the packaging, so they are worth checking at specification.
Do we need a separate return pack?
For part-used containers and returns, usually yes. The contents, the packer and the containment requirement are all different from the outbound journey.