What conditions affect the viscosity of TPE thermoplastic elastomers?

　　1, the influence of temperature

　　Different TPE materials have different sensitivity to temperature, for example, when measuring the melting finger can be measured more than a few temperatures, if the melting finger is very different, it means that the TPE material viscosity is highly sensitive to temperature, suitable for extrusion materials.

　　2, the impact of low molecular additives

　　Low molecular additives can reduce the force between the large molecular chain, thus reducing the viscosity, making it easy to fill the mold forming. This is very good explanation, small molecule additives we can understand the addition of mineral oil.

　　3、The influence of molecular weight

　　The same TPE material can have different molecules and molecular weight distribution, the greater the molecular weight, the stronger the intermolecular forces, reflecting the greater the viscosity, when the molecular weight is the same, the molecular weight distribution is narrower often less viscosity. For example, TPE base material with YH503T is higher viscosity than YH502.

　　4、Influence of shear speed

　　Effectively increase the shear speed of plastic can make the plastic melt viscosity drop, but different plastics are affected by the shear speed is not the same, when measuring the melt finger can be measured more pressure, if the melt finger is a big difference, it means that the material viscosity to shear sensitivity is high, suitable for injection molding materials.

　　5、The influence of pressure

　　Although the high injection pressure in the injection process can improve the injection speed and obtain a large shear effect, it seems to be beneficial to reduce viscosity, but from the physical sense of the pressure, the increase in pressure will increase the melt viscosity, the reason is simple, between the chain of macromolecules and the chain itself to maintain the rock distance, that is the intermolecular force, the increase in pressure means that the molecular distance is reduced, and thus the molecular chain of misalignment appears more difficult Therefore, the overall viscosity of the flow increases.