GB/T 3781.5 - 2006 is a standard for the determination of coarse particle content of acetylene carbon black. This standard specifies the specific methods and procedures for the determination of coarse particle content in Part 5 for acetylene carbon black products. From sample collection, processing to testing operations, there are clear specifications to ensure accurate and reliable measurement results. It provides a unified detection basis for acetylene carbon black manufacturers and users, which helps to control product mass, ensure that the coarse particle content in acetylene carbon black meets relevant requirements, and promote the stable application of acetylene carbon black in various fields.