As an important industrial raw material, carbon black is widely used in rubber, ink, coatings and other fields. In the evaluation of its quality, blackness is an important indicator, which is directly related to its application effect in products. This article introduces the carbon black blackness test method based on the GB/T 7048-2012 standard, aiming to provide accurate and reliable blackness measurement technical support for related industries.
Method overview
This standard uses a reflectometer to measure the blackness of pigment carbon black, using standard reference carbon black No. 3 (SRB3) as the benchmark. The principle is to mix carbon black samples and standard samples with refined linseed oil respectively to prepare an ink slurry film, and then use a reflectometer to measure the reflectivity of the ink slurry film to express the blackness value of the sample.
Reagents and instruments
Reagents include 95% ethanol, refined No. 4 linseed oil, standard reference carbon black No. 3 (SRB No. 3), etc.
Instruments include analytical balances, automatic plate Grinders, reflectometers, ovens, syringes, dryers, ink adjusting knives, ink slurry applicators, etc.
Test steps
After drying appropriate amounts of carbon black samples and standards, they are mixed and ground with refined linseed oil to make ink slurry.
Use an ink applicator to scrape the ink slurry from the glass plate into a thin ink slurry film with a uniform thickness.
Use a reflectometer to measure the reflectance of the standard ink slurry film and the sample ink slurry film, and calculate the blackness value.
Result Calculation and Precision
The blackness of the sample is expressed as reflectivity, and the results are numerically rounded in accordance with GB/T 8170. Repeatability requires that the difference between the two measurement results does not exceed 2.0.
experiment report
The test report must include information such as the name of the sample, identification, standards based on it, test results, SRB3 reflectance value, differences from the prescribed analysis steps, observation of abnormal phenomena, and test date.
Precautions:
During the preparation of the ink slurry, the sample needs to be dried in advance to remove moisture to ensure the accuracy and stability of the ink slurry preparation.
During the operation, it is necessary to strictly follow the steps specified in the standard, especially the application of ink slurry and the measurement of reflectivity, to avoid the impact of operational errors on the results.
In order to ensure the reliability of the test results, the repeatability needs to be controlled to ensure that the difference between the two measurement results does not exceed the specified limit.
Regular calibration of the reflectometer is one of the key steps to ensure test accuracy, and calibration and maintenance should be performed regularly.
The temperature and humidity of the test environment have a certain impact on the test results. The test conditions need to be strictly controlled to maintain stable environmental parameters.
Carbon black blackness test is one of the important means to evaluate the quality of carbon black. Accurate blackness value is of great significance to product development and production. This article introduces the blackness test method specified in the GB/T 7048-2012 standard. Its rigorous operation process and accurate result calculation can provide reliable quality control support for carbon black production and related industries. This method adopts a standardized operating process, including ink slurry preparation, film coating and reflectance measurement steps, ensuring the consistency and comparability of the test. The use of a reflectometer can provide high-precision reflectivity measurement and ensure the accuracy of blackness test results. Standard reference carbon black No. 3 serves as a benchmark sample and can provide a reliable reference standard to help achieve quality control and comparison. The instruments and reagents used in this method are generally easily available and easy to operate, and are suitable for blackness detection at industrial production sites.
