What factors affect the viscosity of TPE plastics?
TPE is thermoplastic elastomer rubber, which contains a series of soft plastics such as TPE, TPR, TPU, TPV and so on. Its physical properties can be adjusted freely according to the needs of the product, and there are many performance parameters involved. TPE has the elasticity of rubber at room temperature. After high temperature heating, it can be formed by extrusion, injection molding and blow molding. So what factors affect the viscosity of TPE plastics? The following is the introduction of Zhongsu Xiaobian.
Different materials have different sensitivity to temperature. For example, when measuring the melt index, you can measure several more temperatures. If the melt index is very different, it indicates that the material viscosity is highly sensitive to temperature and is suitable for extrusion materials.
Although high injection pressure can increase the injection speed and obtain large shear effect in the injection process, which seems to be beneficial to reducing the viscosity, from the physical meaning of pressure, pressurization will increase the melt viscosity. The reason is very simple. The rock distance between macromolecular chains is maintained, which is caused by intermolecular force. The increase of pressure means the reduction of molecular distance, so the dislocation between molecular chains is more difficult, The overall flow viscosity increases.
3. Molecular weight
The same material can have different molecular weight and molecular weight distribution. The greater the molecular weight, the stronger the intermolecular force, and the greater the viscosity reflected. When the molecular weight is the same, the viscosity with narrow molecular weight distribution is often smaller. For example, yh503t for TPE substrate has higher viscosity than yh502.
4. Low molecular weight additive
Low molecular weight additives can reduce the force between macromolecular chains, so as to reduce the viscosity and make it easy to fill the mold. This is very easy to explain. Small molecule additives can be understood as mineral oil added.
5. Shear velocity
Effectively increasing the shear speed of plastics can reduce the viscosity of plastic melt, but different plastics are also affected by the shear speed. When measuring the melt index, you can measure several more pressures. If the melt index is very different, it shows that the material viscosity is highly sensitive to shear and is suitable for injection molding materials.
As for the factors affecting the viscosity of TPE plastics, we can share here. The physical properties of TPE (specific gravity, tensile strength, hardness, rebound, hand feel, wear resistance, aging resistance, etc.) can be adjusted. Therefore, the figure of thermoplastic elastomer TPE \ TPR material can be seen in the electrical industry, hardware handles, luggage accessories, fitness equipment, toy dolls, auto parts and other fields.