Polymer-Bound Masterbatches Explained: Binders, Active Content and Product Codes
If you buy rubber chemicals in polymer-bound form, the product code on the box tells you almost everything you need to know. This article explains how polymer-bound masterbatches are made up, how to read the codes and how to pick the right binder.
What is a polymer-bound masterbatch?
A polymer-bound masterbatch – also called a masterbatch polymer bound chemical, polymer-bound predispersion or predispersed chemical – is a rubber chemical mixed at high concentration into a polymer binder, often with a small amount of processing aid. The finished product is dust-free and contains a known, consistent percentage of active ingredient.
Three things in every product code
Take S 80E as an example:
- S – the chemical (sulphur)
- 80 – the active content (80%)
- E – the binder (EPDM)
So MBTS 75NBR is 75% MBTS in a nitrile binder, and ATR 90CPE is a 90% active flame retardant in chlorinated polyethylene.
Choosing a binder
| Binder | Code | Good fit for |
|---|---|---|
| EPDM | E | The most versatile choice; EPDM and many general-purpose compounds |
| Natural rubber | NR | NR compounds where a non-NR binder is unwanted |
| Styrene butadiene | SBR | SBR and NR/SBR blends |
| Nitrile | NBR | Oil-resistant compounds where polymer compatibility is critical |
| Chlorinated polyethylene | CPE | CPE and halogenated compounds |
As a rule, choose the binder that matches or is fully compatible with your base polymer, especially for oil-resistant or high-specification compounds.
Why active content matters
Higher active content means less binder added to your compound, but the product must still disperse well. Most of our grades sit between 70% and 90% active, balancing concentration with handling and dispersion. When converting from powder, divide the powder phr by the active fraction (e.g. 2.0 phr sulphur ÷ 0.8 = 2.5 phr S 80E).
Benefits of polymer-bound masterbatches
- Even dispersion and consistent cure
- Dust-free handling and a cleaner mill room
- Reduced cross-contamination between compounds
- Faster, more repeatable weighing
What’s in the Chemipat range?
We manufacture accelerator masterbatches, vulcanizing agents including sulfur masterbatch and insoluble sulphur, zinc oxide, sulphur donors, antioxidants, blowing agents, retarders, flame retardants and adhesion promoters. Products ship in 25 kg boxes, 500 kg per heat-treated pallet. For a bespoke binder or active level, talk to us.
