Additivi della gomma 101: cosa entra in un composto

1. Cure System

Vulcanisation turns linear rubber chains into a 3-D network. Four core ingredients: curative (sulphur / peroxide), accelerator (CZ, NS, DM, TMTD), activator (zinc oxide + stearic acid) and retarder (CTP/PVI).

Selection: NR and SBR are usually sulphur-cured; EPDM and silicone often use peroxide curing for better heat resistance. Accelerator choice sets scorch safety and cure rate — injection and fast extrusion need delayed-action grades such as CZ or NS.

2. Anti-degradants

Amines (6PPD/4020, IPPD/4010NA, TMQ/RD) give excellent ozone and flex-fatigue protection but stain; use them for black compounds. Light-coloured goods need phenolics (BHT/264, 2246) plus microcrystalline wax for physical protection.

3. Reinforcing fillers

Carbon black (N220/N330/N550/N660) delivers reinforcement, abrasion resistance and conductivity. Precipitated/fumed silica is the key to low rolling resistance 'green tyres', normally paired with silane coupling agent Si-69. CaCO3, clay and talc mainly extend and improve processing.

4. Plasticizers

Aromatic, naphthenic, paraffinic oils, TDAE and DOP/DOTP. For EU exports watch PAHs and REACH — prefer TDAE or naphthenic grades.

5. Buying checklist

Confirm before ordering: grade and standard (GB/ASTM/ISO); particle size or purity; heating loss, ash, sieve residue; availability of COA, MSDS, REACH/RoHS statements; packaging (25 kg paper-plastic bag / jumbo bag / palletised).