A masterbatch is a concentrate of pigment, filler or additive in a carrier resin. You mix a small amount with your base polymer to colour it or change its properties, which is cleaner and more consistent than adding powders.
The main types
- White: titanium dioxide, often 50 to 75 %, for opacity and whiteness.
- Black: carbon black, for colour and UV protection; pipe and film need fine dispersion.
- Colour: matched to a colour standard or your sample.
- Filler: mostly calcium carbonate, to reduce cost and change stiffness in film, raffia and injection parts.
- Additive: UV stabiliser, slip, antiblock, antistatic, antifog, flame retardant and others.
Carrier resin
The carrier should suit your base polymer: PE carriers for PE film, PP carriers for PP, or universal carriers for several polymers. A wrong carrier can cause poor mixing or weak film.
Let-down ratio
The let-down ratio is how much masterbatch you add, usually 1 to 5 % for colour and additives, and much more for filler. A higher concentration lets you add less, but needs good mixing.
What to check
- Dispersion quality, especially for thin film and fibre
- Colour match under your lighting, and heat stability at your processing temperature
- Melt flow compatible with your base resin
- Food-contact or toy regulations for your market
What to send for a quote
- Type, and the colour standard or a sample
- Your base polymer, product and process
- Target let-down ratio
- Quantity, packing, destination port and Incoterm