Switching Masterbatch Suppliers Without Stopping the Line

Switching masterbatch supplier is rarely a product decision. The product has usually been evaluated already. What makes people hesitate is the risk — of a shade shift halfway through an order, of a dispersion problem discovered at two in the morning, of a compliance document that turns out not to cover the new grade.

All of those are manageable. Most of the pain comes from switching in a hurry, after the existing relationship has already broken down. Here is how to do it deliberately.

Switch before you have to

The worst time to change supplier is when the current one has just failed you. You are under pressure, you have no time to qualify properly, and you will accept a trial that proves less than it should.

If you are unhappy with a supplier, start qualifying an alternative while the current one is still working. The qualification costs the same either way, and doing it calmly is the whole difference.

Qualify fully before you commit anything

Run the full trial protocol — written pass criteria, controlled conditions, incumbent running alongside, multiple batches. See how to run a masterbatch trial.

Do not shortcut the multi-batch step. A supplier who makes one excellent batch and an inconsistent second one is worse than the supplier you are leaving, and you will only discover it after you have committed.

Decide what you are actually matching to

This is the decision that causes the most trouble, and it should be made explicitly.

Option A: match to the original specification. If you have a retained standard and a documented tolerance from when the part was first approved, match the new supplier to that.

Option B: match to what you are currently receiving. If the incumbent has drifted over the years, your customers have been accepting the drifted colour and may now notice a “correct” one.

Neither is automatically right. What is wrong is not deciding, and then being surprised when the new material is measurably correct and visibly different from last month’s delivery.

If you have assembled products where a new component sits next to older stock, this matters a great deal.

Keep what you can from the old supplier

Before the relationship ends, ask for:

• Your retained colour standard returned, or at least spectral data for it
• The compliance declarations on file for the grades you have been running, with their dates
• Batch records for recent deliveries, if your industry requires traceability
• The grade specifications as supplied

You are entitled to the things that describe your own product. Ask while the relationship is still cordial, because afterwards is harder.

Note that a supplier’s formulation is theirs, not yours, unless you paid for its development and the contract says so. Do not expect it.

The changeover sequence

1. Build stock of the old material. Enough to cover the changeover window and to fall back on. This is cheap insurance.

2. Pick the right product to start with. Not your most critical part, and not your most difficult colour. Start where a problem is recoverable.

3. Run the first production batch with the technical people present. Both yours and, ideally, the new supplier’s. Problems that take a week to resolve by email take twenty minutes with someone watching the line.

4. Do not purge-and-pray. A clean changeover between masterbatches — especially from dark to light, or between different carriers — needs a proper purge. Residual dark material in a light run is a classic avoidable failure.

5. Inspect the first deliveries harder than normal, and tell your inspectors that you have changed material so they know to look.

6. Keep measuring for the first several batches. The point of the switch is consistency, and consistency is a claim about the future.

Grade-specific risks

Colour

The main risk is a visible step change against existing stock, as above. Also watch for metamerism — the new match may hold under the illuminant you specified and separate under another. Check under every light the part is seen in.

Additive

The risk is invisible and delayed. A UV package that is slightly weaker will not show for a year. Do not accept “equivalent” — test the function. See additive masterbatch.

Watch interactions too: your formulation may contain something that deactivates the new package, even though it was fine with the old one.

Compliance-critical grades

Food contact, toys, potable water, electrical. The declaration does not transfer. You need a new grade-level declaration from the new supplier, and if you are audited you need it on file before the first part ships, not afterwards.

Check whether your own customers require notification of a raw-material change. Many do, and many switchers forget.

PET

Carrier compatibility, drying discipline and IV behaviour all change with supplier. Do not assume a PET grade from a new source behaves like the last one. See PET masterbatch.

Dual-running, and when it is worth it

For a critical part, running both suppliers in parallel for a period is expensive and sometimes correct. You keep a qualified alternative live, which protects you from exactly the situation that caused this switch.

For most processors, the cheaper version is to keep a second supplier qualified but not running — a documented trial on file, a known contact, and a retained standard they hold. Requalifying from scratch during a crisis is what you are trying to avoid.

What to tell your customers

If you supply a part to a specification, check whether a colourant change is a notifiable change under your agreement. In automotive, medical and some food supply chains it is.

Even where it is not contractually required, telling a customer in advance that you have changed material — and that you have test data showing equivalence — is a much better conversation than having them notice.

Talk to us

We would rather be qualified slowly than win in a panic, because a supplier chosen under pressure tends to be replaced under pressure.

We will supply material from separate production batches so you can measure consistency, match in your resin, give grade-level compliance declarations for your end market, and be present for your first production run.

Tell us what you currently run, what is not working, your polymer and process, and your colour standard, and we will propose a qualification programme rather than a price. Related: colour masterbatches, white masterbatches, black masterbatches, PET masterbatches, about us.

Frequently asked questions

When is the right time to switch masterbatch supplier?

While the current one is still working. Qualifying an alternative under pressure, after a failure, forces shortcuts in the trial and tends to produce a supplier you replace again later.

Should a new supplier match my original specification or my current deliveries?

Decide explicitly. If the incumbent has drifted over the years, your customers have been accepting the drifted colour, and a technically correct match may look visibly wrong against existing stock. The error is making the decision by accident.

What should I get from my old masterbatch supplier before leaving?

Your retained colour standard or its spectral data, the compliance declarations on file for your grades, batch records if your industry needs traceability, and the grade specifications. Ask while the relationship is still cordial. The formulation itself is theirs unless you paid for its development.

Do compliance certificates transfer when I change masterbatch supplier?

No. Food contact, toy safety, RoHS and similar declarations are specific to the grade and the manufacturer. You need a fresh grade-level declaration from the new supplier, on file before the first part ships.

What is the safest way to sequence a masterbatch changeover?

Build a fallback stock of the old material, start on a non-critical part and an easy colour, have technical people present for the first production run, purge properly between materials, inspect the first deliveries harder than normal, and keep measuring for several batches.

What is the biggest risk when switching additive masterbatch?

That the failure is invisible and delayed. A slightly weaker UV package shows up a year later in the field, so the function has to be tested rather than accepted as equivalent. Interactions with the rest of your formulation also need rechecking.

Should I tell my customers I have changed masterbatch supplier?

Check your supply agreements – in automotive, medical and some food chains a colourant change is notifiable. Even where it is not, telling a customer in advance with test data showing equivalence is a far better conversation than having them discover it.

Is it worth keeping two masterbatch suppliers running?

For critical parts sometimes. For most processors the cheaper equivalent is to keep a second supplier qualified but not running – a documented trial on file, a known technical contact and a retained standard they hold – so you never have to requalify during a crisis.