The optimal dosage of white carbon black needs to be dynamically adjusted according to the type of rubber, application scenarios, and performance goals, usually within the range of 5% to 50% (or 5-50 phr, adding grams per 100 grams of rubber).
1、 Typical application scenario usage
1. Tire manufacturing:
The addition amount of tread rubber is 35-50 phr, which significantly improves wear resistance and wet road grip, but it needs to be combined with silane coupling agent to prevent filler agglomeration.
2. Footwear products:
The amount of rubber added to the sole is 20-30 phr, which balances wear resistance and wearing comfort. Excessive use can easily lead to an increase in hardness.
3. Sealed products:
For example, for door and window sealing strips or shock-absorbing components, the addition amount should be 10-20 phr, with a focus on optimizing the compression permanent deformation performance. Excessive amounts may cause problems with processing rollers.
4. Ethylene propylene diene monomer (EPDM):
Dosage: 5-30 parts (equivalent to 5-30 phr), used to enhance strength, hardness, and flame retardancy; If the amount is less than 5 parts, the reinforcement is insufficient, and if it is higher than 30 parts, the elasticity and flexibility will be reduced.
5. Recycled rubber products:
When combined with natural rubber, the dosage should be controlled at 40-50 parts, taking into account both cost and performance; Light colored products can replace carbon black as a reinforcing agent.
2、 Key factors affecting dosage
1. Rubber type: Natural rubber has a higher tolerance than synthetic rubber (such as styrene butadiene rubber with an upper limit of about 35 phr).
2. Target performance:
Higher usage is required to increase strength and hardness (such as tensile strength ≥ 17.0MPa); Improving liquidity or processing performance requires reducing usage. For every 5 degrees increase in Shore hardness, the addition amount needs to be increased by 8-12 phr, but the incremental effect decreases after exceeding 60A.
3. Cost and process: White carbon black has a high price, and economic usage should be controlled while meeting performance requirements; Insufficient dispersibility in the production process may require the addition of surfactants (such as diethylene glycol, with a dosage of 5% -10% of white carbon black).
4. Particle size and purity: Smaller particle sizes (<100nm) enhance the filling effect, but need to match the pore structure; Industrial grade purity (≥ 90%) is usually sufficient, while high-end applications require ≥ 99.8% gas-phase products.
In practical applications, it is necessary to determine the final dosage through formula testing and process optimization (such as adjusting the mixing sequence) to avoid performance degradation or cost waste.