Medium resistance of natural rubber. Natural rubber has good alkali resistance, but it is not resistant to strong acid. Because natural rubber is nonpolar rubber, it can only resist some polar solvents, but it will swell in nonpolar solvents, so its oil resistance and solvent resistance are very poor. Generally speaking, hydrocarbons, halogenated hydrocarbons, fluidized carbons, ethers, higher ketones and higher fatty acids can dissolve natural rubber, but their solubility is affected by the degree of plasticization, while lower ketones, lower esters and alcohols are non-solvents of natural rubber.