What this blog covers
This guide to colour masterbatch covers:
- Why processors use colour masterbatch instead of raw pigment
- How colour matching works, stage by stage
- What affects colour consistency in production
- How to brief your masterbatch supplier
- Frequently asked questions about colour masterbatch
Why use colour masterbatch instead of raw pigment?
Colour masterbatch gives cleaner, more accurate colouring than raw pigment powder. The pigment arrives already dispersed in a resin carrier. Pellets dose easily through standard hopper or gravimetric feeders. The dispersed pigment spreads evenly throughout the melt, helping reduce streaks and specks.
For a broader introduction, read The invisible ingredient that colours your world.
Is coloured masterbatch the same as colour masterbatch?
Coloured masterbatch and colour masterbatch are two names for the same product. Both describe pellets that colour plastic during processing. Some suppliers also use the term “colour concentrate”. Black and white masterbatches are usually sold in separate ranges due to their high volumes.
Read more in our guides to black masterbatch and white masterbatch.
How does colour matching work?
Colour matching turns a target colour into a masterbatch recipe for your polymer and process. It runs in five stages: agree a standard, share processing details, trial, adjust, then approve. Turnaround depends on the colour and the number of trial rounds needed.The approved recipe then fixes the colour for every production batch.
Colour matching at a glance
| Stage | What happens | What you supply |
|---|---|---|
| 1. Standard | The target colour is agreed | A RAL or Pantone reference, or a physical sample |
| 2. Details | The formulator reviews how the colour will be used | Polymer, process, thickness, addition rate |
| 3. Lab trial | Pigments are selected and a trial plaque is moulded | No extra input needed |
| 4. Adjust | The plaque is measured and the recipe refined | Feedback on trial samples |
| 5. Approve | The recipe is fixed and production starts | Sign-off on the final sample |
What colour reference should I give my masterbatch supplier?
A physical sample in the same polymer gives the most accurate colour match. A RAL or Pantone number is a common alternative. Moulded parts, plaques and competitor samples also work as references. Printed cards and screen colours are only guides, since plastic rarely looks like ink on paper.
What processing details does a colour match need?
A colour match needs the base polymer, the process and the part thickness. The formulator also needs your intended addition rate and processing temperature. Opacity also matters, since a bottle cap or film may need to remain translucent. Thin films and thin-walled parts may require more pigment to reach full opacity.
How is a colour match made in the lab?
The lab selects pigments and compounds a small trial batch of masterbatch. The trial is let down into the base polymer at your addition rate. It is then moulded or pressed into a test plaque. Colour is commonly measured with a spectrophotometer and checked by eye in a light booth.
What is Delta E in colour matching?
Delta E is a single number for the colour difference between a sample and its standard. A lower Delta E means a closer match. The buyer and supplier for each project agree upon the acceptable Delta E. The lab adjusts the recipe until the sample sits inside the agreed tolerance.
How is a colour masterbatch approved for production?
The customer signs off the final lab sample against the original standard. The recipe is then fixed, and the masterbatch goes into production. Production batches are typically checked against the approved standard. The approved sample can then act as the reference for later orders.
What affects colour consistency in production?
Six common factors can shift colour on the production line. They are the base polymer, addition rate, processing temperature, part thickness, lighting and recycled content. Each one can move the shade even when the masterbatch itself stays the same.
| Factor | Effect on colour | How to control it |
|---|---|---|
| Base polymer | PE, PP and PS each have their own tint and clarity | Match in the polymer grade you run |
| Addition rate | Too little or too much changes the depth of shade | Calibrated dosing units and a fixed let-down ratio |
| Processing temperature | Some pigments shift or fade at high melt temperatures | Pigments rated for your process temperature |
| Part thickness | Thinner sections look lighter and less opaque | A match made at the finished part’s thickness |
| Lighting | A daylight match can fail under shop lighting | Checks under more than one light source |
| Recycled content | Recycled polymer often carries its own tint | An adjusted formulation or dose |
What is metamerism in plastic colour?
Metamerism is when two colours match under one light and differ under another. It happens because different pigments reflect light in different ways. Metamerism is a common cause of colour complaints from customers. Tell your supplier where the product will be seen so that they can choose stable pigments.
How does recycled content affect colour matching?
Recycled polymer is rarely colourless, and its tint varies from lot to lot. That tint shifts the final shade of any colour masterbatch added to it. Darker shades tend to be easier to hold with high recycled content. The formulation or dose may need to be adjusted when the recycled source changes.
Our article on masterbatch and recycled content goals covers this in more detail.
How should I brief my masterbatch supplier?
A good brief gives your supplier the colour standard, polymer, process and addition rate. It should also cover thickness, opacity, performance needs, compliance rules and end-use lighting. A complete brief usually cuts the number of trial rounds.
Use this checklist when you request a colour match:
- The colour standard, ideally a physical sample in the same polymer
- The base polymer and grade
- The process, such as injection moulding, blown film or extrusion
- Part thickness and opacity requirements
- Your preferred addition rate
- Any UV, heat or other performance needs
- Compliance requirements, such as food contact or toy safety
- Where and under what lighting customers will see the product
Colour and additives can be shared in one pellet. A garden chair might carry its colour and a UV stabiliser in one masterbatch
Read more about UV-resistant masterbatch for outdoor products and additive masterbatch.
Why use a specialist masterbatch manufacturer?
A specialist manufacturer understands how pigments behave in different polymers and processes. That experience can cut lab trials and reduce colour drift on the production line. Abbey Masterbatch has made masterbatch and pigment dispersions in Ashton-under-Lyne, UK, since 1984. The business is independent and family-owned, with three generations working in the company. Our range covers colour, black, white and additive masterbatches. We also make liquid colour concentrates and pigment dispersions. We hold ISO 9001 certification. Over 70% of our sales go to export customers. We won the Queen’s Award for Enterprise in International Trade in 2006.
To discuss a colour match for your products, contact the Abbey Masterbatch team:
- Phone: +44 (0) 161 308 2550
- Email: aml@abbeymb.com
- Online: contact form
Frequently asked questions about colour masterbatch
Is colour masterbatch safe for food packaging?
Colour masterbatch can be used in food packaging when its pigments and carrier comply with food-contact regulations. In the UK and the EU, plastic food-contact materials are regulated by Regulation (EU) No 10/2011. Ask your supplier for a declaration of compliance for each grade.
Read more in our guide to food-safe masterbatch.
What is the difference between colour masterbatch and liquid colour?
Colour masterbatch is a solid pellet, while liquid colour is pigment dispersed in a liquid carrier. Liquid colour is dosed by a pump at the feed throat. It can work at lower addition rates than pellets. Pellets are cleaner to handle and suit most standard hopper setups.
Read more about pigment dispersions.
Do pigments or dyes give better colour in plastic?
Pigments are insoluble particles that give opacity and strong light fastness. Dyes dissolve in the polymer and give bright, transparent colours. Dyes suit clear polymers such as polystyrene, PET and polycarbonate. Pigments suit most polyolefins, because dyes can migrate in polyethene and polypropylene.
Can colour masterbatch be used in bioplastics?
Colour masterbatch can colour bioplastics such as PLA, PBS and starch blends. The carrier resin must suit the biopolymer, or it can weaken the part. Many bioplastics, such as PLA, are processed at lower temperatures than conventional polymers. Compostable products may also need colourants that meet standards such as EN 13432.
Read more in Masterbatch solutions for bioplastics and biopolymers.
Does colour masterbatch affect the strength of plastic?
At normal addition rates, colour masterbatch usually has little effect on mechanical strength. Some organic pigments can alter how polyethene and polypropylene crystallise, potentially causing warping. A supplier can suggest pigments less prone to warping for large or flat mouldings. Overdosing can also reduce impact strength, so keep to the recommended rate.
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