ISO 9177-2:1989 PDF Download

The black leads used in mechanical pencils are the subject of the 1989 standard ISO 9177-2. According to the standard, the binding agent used to create the black leads is divided into two types. Black leads with an organic polymer binding agent are included in the first category and are identified by the letter "P.". The letter "C" designates the second type, which consists of black leads with a clay binding agent.

The standard further divides the black leads into groups based on how hard they are. The classification is an important factor since it aids consumers in identifying and selecting the appropriate sort of black lead for their unique requirements or preferences. It guarantees that a uniform structure is in place for straightforward comparison and choice.

Black lead size, performance specifications, and testing methods are all covered by ISO 9177-2:1989 as well. However, Part 1 of the standard goes into great detail about these elements. In order to assure uniformity and compatibility in mechanical pencils, this standard primarily focuses on the classification and size of black leads and provides instructions for makers and users.