Thermoplastic elastomer TPE has excellent environmental protection performance, which makes it widely used in conventional fields, but also gradually penetrates into the medical and food utensils industry. Food-grade testing is generally required for food utensils products. So what is the concept of food-grade TPE? For TPE food-grade testing, the American FDA standard refers to the FDA 2600 standard, that is, through distilled water and n-hexane detection!
This is a relatively general concept about food-grade TPE. TPE used in food industry should be determined according to the actual product application of TPE. For food contact products such as food packaging boxes, tableware handles, etc., the food-grade detection methods are different from dental gum, tableware, nipples and other oral contact products. For general food contact products, the detection methods are as follows: total extract (distilled water reflux 7 hours) total extract (distilled water reflux 7 hours after initial reflux 2 hours after distilled water reflux); for oral contact products, in addition to the above distilled water test, hexane detection is also required. At present, domestic TPE products can basically be detected by distilled water, which meets the requirements of food contact grade. So whether TPE (TPR) can pass FDA 2600 oral exposure level n-hexane detection?
The following analysis is made:
SYNTHESIS OF SBS: Styrene and butadiene as monomer raw materials, cyclohexane as solvent, n-BuLi as initiator, THF as activator, no termination of anionic polymerization, SiCl4 as coupling agent, finally adding appropriate amount of antioxidant. The product is white translucent elastomer.
Generally, polymer polymerization is incomplete. The solvent cyclohexane and small molecules of polymer monomer (usually butadiene, styrene and other small molecules) always exist more or less in polymer SEBS, SBS, and these small molecules will remain in SEBS, SBS polymer modified material TPE, TPR system all the time. Hexane and cyclohexane have good mutual solubility, and n-hexane can be dissolved in most non-polar organic solvents. Therefore, when TPE and TPR are used for FDA 2600 detection, n-hexane is used as extractant. The small residual molecules in TPE and TPR materials are easy to be separated, which results in the detection results exceeding the standard.

Based on the above analysis, the conclusion that whether SEBS, SBS, TPE and TPR can pass the FDA2600 oral contact level test is that it is very difficult! Although many TPE and TPR manufacturers in China claim that their products can be tested by FDA 2600 in the United States and some can produce FDA test reports, in fact, few of them can really pass the test of n-hexane. Even if they can pass, they only refer to TPE representing special formulations, and the price of such TPE is usually very high. It's expensive. Typically, TPE and TPR materials of price and formula are difficult to detect through FDA 2600. But for some imported TPE models, customer feedback can be detected through FDA 2600 or even LFGB!