As the core equipment for quality control of powder materials, the oil absorption tester's measurement principle and titration kinetics mechanism directly determine the accuracy and repeatability of the test results. This instrument achieves precise quantification of the oil absorption capacity of materials such as carbon black, white carbon black, and pigments by dynamically monitoring the torque changes during the oil absorption process, combined with high-precision titration control.

Measurement principle: dynamic response mechanism of torque viscosity

The instrument adopts the torque method as the core measurement principle, which essentially captures the physical signal of viscosity changes during the material's oil absorption process. When the titration pump injects test oil such as dibutyl phthalate (DBP) into the mixing chamber at a constant rate, the powder material undergoes three stages: free flow stage (linear increase in torque), coagulation stage (sharp increase in torque), and end stage (stable torque). The condensation stage is the key judgment point, at which the internal pores of the material are fully filled with oil, forming semi plastic aggregates, resulting in characteristic inflection points in the torque curve. A high-precision torque sensor (with a resolution of 0.01N · m) captures this change in real time. When the torque reaches a preset threshold (such as 10N · m), the system automatically terminates titration and records fuel consumption.

Titration kinetics: multi-stage rate control strategy

The titration process adopts graded rate control technology, and in the initial stage, high-speed titration (such as 8mL/min) is used to quickly wet the surface of the material, shortening the testing cycle; Switch to low-speed titration (such as 2mL/min) during the coagulation stage to avoid torque overshoot caused by excessive oil. For example, the TITNIAIO instrument achieves stepless adjustment of titration rate from 0.1 to 10 mL/min through a variable frequency drive unit, coupled with a 100 mL high-precision metering pump (with an error of ± 0.5%), ensuring a titration volume accuracy of 0.01 mL. This dynamic control results in test repeatability (CV value) better than 0.5%, meeting the stringent requirements of ASTM D2414 standard for carbon black oil absorption value testing.

Application verification: correlation between material properties and processes

In the rubber industry, the oil absorption value (DBP value) of carbon black directly reflects its structural degree. High structure carbon black (DBP>120mL/100g) requires more oil to fill the pores due to loose chain like aggregates, giving rubber excellent reinforcement. In the field of battery materials, the oil absorption value of conductive carbon black affects the stability of electrode slurry. As shown by the S500 instrument test, when the oil absorption value of a certain type of conductive carbon black reaches 180mL/100g, its specific surface area is positively correlated with electrolyte wettability, significantly improving battery charging and discharging efficiency.