How to Distinguish Dirt, Ash and Volatile Matter?
Quick AnswerDirt, ash and volatile matter are distinct quality dimensions and must not be added up as "total impurities"; they should be judged separately against applicable methods and contractual limits.
Parameter Breakdown
Dirt measures insoluble contaminants by the specified method; Ash reflects the residue after ignition; Volatile Matter (VM) covers moisture and other volatile components. ISO 249 specifies the test method for dirt in raw natural rubber.
Deviation Handling
When abnormal values are found, first verify the original certificate, units, sampling and test methods, then determine whether contractual limits are exceeded. Do not apply an unsuitable grade specification to a different product.
Sources & Further Reading
- ISO 249:2016 天然生胶杂质测定
- ISO 2000:2020 技术分类天然生胶规格指南
- RIOMI 橡胶业务编辑与项目经验（2026-10 编审）