Classification of Rubber Additives (By Physical Form) Powder / Oil-treated Powder / Granule / Liquid / Pre-dispersed Masterbatch

Rubber additives are commonly divided into 5 types based on different physical forms: powder, oil-treated powder, granule, liquid and pre-dispersed masterbatch. The specific differences are explained from the perspectives of concept, characteristics and application:

1. Powder Additives

  • Concept: A traditional form, fine solid particles obtained directly through chemical synthesis, mechanical crushing and other processes, with some particle sizes reaching over 300 meshes.
  • Characteristics: Mature production process, low raw material cost and excellent chemical stability of products; however, it is prone to dust generation and insufficient mixing and dispersion uniformity (easy agglomeration).
  • Application: General rubber products, such as anti-scorch agent CTP crystal powder/powder, accelerator DM powder.

2. Oil-treated Powder Additives

  • Concept: An oily mixture formed by adsorbing mineral oil or synthetic oil on the surface of powder additives (oil content is usually 1%–3%, and can be adjusted to within 5% for some products as required).
  • Characteristics: Effectively suppress dust and significantly improve dispersion effect; may slightly affect vulcanization speed only in special formulations.
  • Application: Occasions requiring a balance between cost and environmental protection, such as oil-treated powder of accelerator series products (e.g., accelerator CZ oil-treated powder, accelerator BZ oil-treated powder).

3. Granular Additives

  • Concept: Particles with a diameter of 1–6mm formed by compressing or bonding powder through granulation process.
  • Characteristics: Dust-free and good fluidity (suitable for automatic weighing); additional granulation cost is required, and the dispersion speed of some traditional extrusion granulation products is slightly slow, while modern granulation technology can achieve dispersion efficiency equivalent to that of powder.
  • Application: Scenarios with certain on-site requirements, such as anti-aging agent RD granules, 6PPD granules, accelerator DM granules, accelerator NS granules.

4. Liquid Additives

  • Concept: A homogeneous fluid formed by dissolving or suspending additives in liquid carriers (e.g., plasticizers, solvents).
  • Characteristics: Special storage equipment is required (to prevent leakage), and some liquid additives have high volatility.
  • Application: High-performance tires, shoe materials, medical silicone rubber products, such as accelerator ZDTP liquid.

5. Pre-dispersed Masterbatch

  • Concept: Homogeneous granules formed by pre-dispersing additives in rubber carriers (e.g., SBR, EPDM) and then extruding and granulating (additive content is 60%–80%).
  • Characteristics: Easy to disperse (improving performance consistency), completely dust-free and suitable for high-precision formulations; relatively high price (attributable to carrier cost and complex production process).
  • Application: High-demand rubber products such as tires, shoe materials and seals, e.g., S-80, ZnO-80, accelerator M-80.

Selection Considerations

  • Environmental Protection: Granular additives or pre-dispersed masterbatch (complying with national or industrial standards).
  • Cost: Powder additives or oil-treated powder additives (equipped with dust removal and internal mixing equipment as required).
  • High-precision Requirements: Pre-dispersed masterbatch (e.g., high-end seals for aerospace and other fields).
  • Production Method: Granular additives or pre-dispersed masterbatch are preferred for automatic production lines; oil-treated powder additives can be used for manual feeding to balance cost and environmental protection.