Most masterbatch enquiries arrive as one line: “Need price for black masterbatch, 5 MT monthly.” A supplier can only respond to that with a guess and a hedged price, and the quotes you get back from three suppliers will not be comparable, because each has quietly assumed a different product.

A specification that takes ten minutes to write gets you comparable quotes, a shorter development cycle, and a much better chance that the first sample runs. Here is what to put in it.

1. The base polymer — exactly

Not “PE”. Say LDPE, LLDPE or HDPE, name the grade, and name the producer if you know it. Melt flow index matters: a carrier that disperses well into a 20 MFI resin may not into a 0.3 MFI one.

If you run regrind, say what percentage. It affects both shade and the mechanical properties the supplier is formulating around, and a supplier who finds out about your 30% regrind after the sample fails has lost a fortnight for no reason.

2. The process

Injection moulding, blown film, cast film, sheet extrusion, pipe, blow moulding, roto-moulding or fibre. Each puts different demands on dispersion and thermal stability.

Add the numbers that matter for your process:

  • Film — gauge, and whether mono or multi-layer
  • Injection — wall thickness and cycle time
  • Pipe and sheet — wall thickness and line speed
  • Fibre — denier and filtration, because pigment particle size becomes critical

Also give your processing temperature range. A pigment that is stable at 200°C may char at 280°C, and this is the single most common cause of a sample that looks nothing like the target.

3. The colour, as a reference not a word

“Dark blue” is not a specification. Send one of:

  • A Pantone, RAL or NCS code — the most reliable option
  • A freshly moulded part in your actual polymer and process
  • A spectrophotometric reading if you have the equipment

Avoid sending an old part. It has faded, yellowed or picked up surface film, and your supplier will faithfully match the degraded version. If a part is all you have, say how old it is and what it has been through.

State your tolerance too. If you hold a Delta-E limit, say the number and the illuminant. If your product is sold on a shelf, say so — that tells the supplier to check the match under more than one light source rather than only under lab conditions.

4. Performance requirements

This is where most specifications go thin, and it is where the money is. Be explicit about what the part must survive:

  • Outdoor exposure — expected service life and geography. Two years in Rajasthan is not two years in Kerala.
  • Food, pharmaceutical or toy contact — name the standard you are certifying against, not just “food grade”
  • Flame retardancy — the standard and rating, e.g. UL 94 V-0
  • Antistatic, anti-fog, antimicrobial, slip — and the target value if you have one
  • Opacity — for whites, the gauge you need to hide at

Naming the standard rather than the property is the difference between a supplier confirming compliance and a supplier hoping. See additive masterbatches for what can be combined into a single product rather than dosed separately.

5. Commercial terms

Volume per month and per order, expected number of shades, packaging preference, delivery location, and whether this is a trial or a running requirement.

Say if it is a trial. Suppliers price and prioritise trials differently from committed volume, and pretending a trial is a running order tends to produce a quote you cannot hold them to later.

6. What you are replacing

The most useful line in any enquiry, and the one most buyers leave out: what are you using now, and what is wrong with it?

“Current supplier is fine but lead time is six weeks” and “current material shows specks in thin sections” lead to completely different responses. The first is a logistics conversation. The second is a dispersion problem, and the supplier can go straight at it instead of spending two rounds discovering it.

If you are switching because of a technical failure, describe the failure. It is not a weakness in your negotiating position — it is the fastest route to a material that works.

A template you can copy

Paste this into your next enquiry and fill the blanks:

  • Base polymer: grade, producer, MFI
  • Regrind: % and source
  • Process: and key dimensions (gauge / wall / denier)
  • Processing temperature: range
  • Colour reference: Pantone / RAL / NCS / sample
  • Colour tolerance: Delta-E and illuminant, if held
  • Performance: UV life, compliance standards, FR rating, other additives
  • Volume: per month, per order, number of shades
  • Packaging and delivery: location and preference
  • Currently using: and what is wrong with it
  • Trial or running:

What a good quote looks like coming back

A supplier working from a real specification should return more than a price. Expect the recommended let-down ratio, so you can calculate cost per kilogram of finished part rather than per kilogram of masterbatch — a cheaper masterbatch at a higher let-down is often the more expensive material.

Expect a sample offer, a lead time for both sample and production, and a straight answer on any compliance you asked about. A supplier who quotes a price and nothing else has not read your specification.

Once you have that, the three quotes on your desk are finally comparing the same thing.

Send us a specification and we will come back with a grade recommendation, a let-down ratio and a sample — not just a number.