First of all, we need to know the principle of human smell. The reason why people feel the smell of fragrance and odor is actually the molecules of a certain substance diffused into the human nose, which makes the human olfactory organs produce a series of reflections and form specific information into the brain, thus forming a certain odor judgment, such as aroma, odor, etc. So the odors we smell are small molecules that are volatilized into the air by the product.

　　Speaking of small molecules volatilized into the air, we have to mention a parameter in the raw materials - VOC (volatileorganic compounds) volatile organic compounds. There are two possibilities for no taste, one is that the material volatile small molecules itself has no smell, such as water; rather, will not volatile small molecules at all, such as table salt and other solids. But there is only one possibility of having a smell, that is, small molecules can be volatilized, and small molecules have an odor.

　　So elastomer formulations are most likely to volatile is a variety of oils, oil is good or bad directly affect the size of the product odor; the second is the content of each of the other formulations material VOC, try to choose a small VOC content of raw materials. And elastomer all kinds of raw materials are synthesized when the various organic solvents, the smell is inevitable, so the smaller the VOC content, the lighter the smell of the product.

　　At the same time, processing and mixing to minimize the destruction of the long chain, temperature and shear force should not be too high, appropriate, and oil absorption should be sufficient, all in order to reduce VOC.

　　Cold performance in which pieces, the rubber molecular chain will be reduced with the temperature, the ability to reduce activity, hardness, modulus and molecular friction increased to a certain low temperature when the molecular chain freeze, hardening completely lose elasticity, rubber or elastomer on the "plasticized". This temperature is the Tg glass transition temperature, but not all low temperature resistant materials are marked with Tg, because for some non-crystalline materials does not apply.

　　The influence of each component of the formulation on the low temperature resistance factors, right.

　　1.SEBS/SBS base material

　　It can be said that TPE/TPR inside the most important is SEBS/SBS, the impact is also the largest. Styrene and butadiene are hard and soft, so the lower the styrene content, the better the low temperature resistance of TPE/TPR.

　　2.TPE/TPV base material

　　For non-crystalline elastomer materials, the lower the cross-link density, the better the low-temperature resistance of the material, no chemical cross-linking TPE natural than TPV low-temperature resistance is better.

　　3. The choice of softening oil

　　White oil and other oils can reduce the hardness of the elastomer, low temperature resistance also has some favorable impact, but in the white oil selection to try to choose a lower pour point of oil.

　　4. The choice of filler

　　Fillers can not be used as far as possible, if you must use, try to choose some soft or spherical fillers, although the addition of fillers will not significantly affect the Tg glass transition temperature, but will affect the low temperature hardness, modulus and the rate of increase in intramolecular friction, so need to consider.