The excellent environmental protection performance of thermoplastic elastomer TPE makes it not only widely used in conventional fields, but also gradually permeates the medical and food appliance industries. Food grade testing is generally required for food appliance products. So what is the concept of food grade TPE? For TPE food grade testing, FDA standard refers to FDA2600 testing standard, i.e. testing with distilled water and n-hexane! Regarding food grade TPE, this is a relatively general concept. For TPE used in food industry, different food level testing requirements should be determined according to the actual product application of TPE. For food contact products such as food packaging boxes and tableware handles, the food level testing method is different from oral contact products such as gum, tableware and nipple. For general food contact products, the detection method is as follows: total extract (distilled water refluxed for 7 hours) total extract (distilled water refluxed for 2 hours after initial refluxing for 7 hours); For oral contact products, besides the distilled water test above, normal hexane test is also required. At present, domestic TPE products can basically pass distilled water testing, meeting the requirements of food contact level. Can TPE(TPR) pass FDA2600 oral contact grade n-hexane test? Now do the following analysis: Synthesis of SBS: styrene and butadiene are used as monomer raw materials, cyclohexane is used as solvent, n-BuLi is used as initiator, THF is used as activator, anionic polymerization reaction is not terminated, SiCl4 is used as coupling agent, appropriate amount is finally added, antioxidant is added after reaction is terminated. The product is white translucent elastomer. Generally, the polymerization of polymers is incomplete, and its solvent cyclohexane and polymer monomer small molecules (usually butadiene, styrene and other small molecules) are always more or less present in polymers SEBS and SBS, and these small molecules will continue to stay in SEBS,SBS polymer modified materials TPE and TPR systems. Because n-hexane and cyclohexane have good mutual solubility, and n-hexane can be dissolved in most nonpolar organic solvents. Therefore, when TPE and TPR are tested by FDA2600, n-hexane is used as extractant, and the residual small molecules remaining in TPE and TPR materials are easy to separate out, thus causing the test results to exceed the standard. According to the above analysis, whether SEBS,SBS,TPE,TPR can pass the FDA2600 oral contact level test, the conclusion is-very difficult! Although many TPE and TPR manufacturers in China claim that their products can pass the FDA2600 test and some can produce FDA test reports, in fact, very few manufacturers can pass the n-hexane test. Even if they can pass, they only refer to TPE that represents a special formula, and the price of such TPE is usually very expensive. TPE and TPR materials with normal price and formula are difficult to detect through FDA2600. However, for some imported TPE models, customer feedback can be detected through FDA2600 or even LFGB!