Caps, also known as 3-cyclohexylaminopropanesulfonic acid, is a kind of biological buffer. Its appearance is white crystal or powder. Caps can be dissolved in water, pH buffer range is 8.9-10.3, pKa value is 9.6, molecular weight is 243.28, CAS number is 1135-40-6. Caps has a wide range of applications, including DNA / RNA extraction kit, PCR diagnostic kit, biochemical diagnostic kit, welding materials, air conditioning equipment, lithium metal, new coatings, new industrial materials, etc. In the extraction of nucleic acid, the solution for nucleic acid hybridization can be prepared together with 3 - [(3-choleamidopropyl) dimethylammonium] - 1-propanesulfonate (chaps), 3 - (cyclohexylamino) - 2-hydroxy-1-propanesulfonate (capso), and 2 - (cyclohexylamino) ethanesulfonate (ches). It can reduce the yield of non-specific hybrids and improve the specificity of nucleic acid hybridization, while maintaining the yield of target hybridization products. It has important value in the identification of specific pathogens, diagnosis of genetic diseases, gene sequence analysis and so on. Caps can be used in all kinds of environment-friendly high-quality waterborne two-component polyurethane coatings. Caps can coexist with active genes (hydroxyl, carboxyl, amine, epoxy) for a long time at room temperature. Caps is widely used in coatings market. In addition, caps can react with aliphatic polyisocyanate under mild conditions and in the presence of tertiary amine neutralizer. The sulfonated urea derivative is a very good emulsifier.