The environmental level of silicone is even above TPR. General food contact material test items, mainly water (distilled water), wine (50% alcohol), acid (3% acetic acid), oil (n-hexane or olive oil, etc.) several common solvents to do dissolved residue testing. Most of the silicone can pass these tests, and it is not a problem to pass German LFGB, EU-1935/2004, and US FDA 21CFR177.2600. But TPR based on SEBS substrate, to pass the above several solvent tests will have to be treated with caution. Generally speaking, TPR is not much problem to pass the distilled water, 50% alcohol, 3% acetic acid dissolution test. But for passing the olive oil test there is a probability problem, generally speaking, it is believed that the higher hardness of the TPR (such as hardness 70A or more) through the test has a high chance. For the hexane residue test, for SEBS class TPR, has been an insurmountable hurdle.

The smart bracelet is a wearable smart device. This bracelet allows users to record real-time data on exercise, sleep and diet in their daily lives and synchronize these data with their cell phones to guide their healthy lives through data.

　　Soft PVC is soft to the touch, colorful and inexpensive, so there are many advantages. But PVC contains halogens, and the alcoholic beverage plasticizer incident always makes people associate PVC with toxic plasticizers (phthalates). Although there are relatively more environmentally friendly PVC, PVC material has a large odor, for safety and health reasons, the smart bracelet market is basically not considered to use this material.

　　A simple way to identify soft PVC: an unknown soft rubber material ignited by fire (the fire source does not leave), burning, such as the bottom of the flame color is green, then the soft rubber material is undoubtedly PVC.

　　TPU or PU. these two materials belong to polyurethane, the difference is a thermoplastic (TPU), a casting type (PU). PU can also be processed into leather materials. PU leather has a good soft touch, and there is no smell, can be used as a qualified artificial leather wristband material. Another is TPU.TPU material has excellent elasticity and can be injection bonded with another hard plastic PC of the bracelet. The cost is also relatively cheap, the material can be recycled. The disadvantage is that the soft touch aspect is not ideal. Hardness selection, usually above 70A, softer hardness of TPU, the material required is very high cost.

　　Identification of TPU: TPU burning yellow flame, there is a slight sound of zipping, ammonia odor.

　　3. TPE/TPR. This is actually an elastomeric material based on SEBS. This type of soft material is also thermoplastic and can be injection molded. The advantage of the material is comfortable and soft to the touch, with excellent elasticity, can simulate the effect of soft and smooth skin. It also provides excellent bonding to PC plastics. In terms of hardness and softness, a wide range of Shore 30~90A is available. The material can be recycled, and the cost is not cheaper than TPU, and may even be higher. TPE/TPR is a non-toxic, odorless and safe material with no allergenic effect on human skin. It complies with ISO-10993 test in medical industry. Cost considerations aside, TPE, TPR is the more ideal wrist wristband material, but also in the high-grade smart bracelet wristband material alternative.

　　Identify TPE|TPR: TPE,TPR burning for a special aromatic smell, the flame is yellow on the blue.

　　4. Silicone. Silicone is the top environmentally friendly materials. Silicone elasticity is excellent, smooth to the touch, is a material that allows consumers to feel completely at ease. Processing method is oil pressure molding, the material can not be recycled. The cost is not cheap.

　　Identification of silicone: silicone burning will produce a white powder with a bright flame.