Shallow report foaming extruder and multi-layer extruder
Shallow report foaming extruder and multi-layer extruder
The foaming extruder and multi-layer extruder are one of the many kinds of extruders. Now let's take a look at some basic knowledge about these two extruders.
Foaming extrusion
Thermoplastic elastomer TPV can be foamed by chemical and mechanical methods. For chemical foaming, foaming agents such as heavy hydrochloride can be used. The ratio of foam density can be reached to 0.97 (typical unfoamed TPV) to 0.70. Lower density is influenced by patents. Foaming agent will degenerate under 180 ℃ to 180 ℃, because most of TPV is the basis of under the condition of 195 to 215 ℃.
For mechanical methods, water is the medium. Here, the technology, called "water bubbling," is a patented technology. Special equipment is needed to achieve consistent foam structure and density. The density decreased from 0.97 to 0.20. The density in this range can be obtained by controlling the processing technology. The decrease of density can affect mechanical properties, so this is classified as the shape design of the application.
Multilayer extrusion
The method of co-extrusion is the technique of combining two materials into one part in an extrusion process. Two extruders are concatenated to provide the bottom die and the respective polymer materials are squeezed together along the corresponding channel to get the extrusion of two materials. Homogeneous materials such as TPV and polypropylene can be fused together. Multi-layer extrusion is a good way to mix hard and soft materials. Typically, high hardness section, such as TPV of thermoplastic elastomer, is generally used as the supporting structure of components, while low hardness materials provide flexibility. This is very common in sealing applications because the sealing area is soft and the soft materials can be squished to get a good sealing effect. In the equilibrium flow field, it is simpler to use the high hardness thermoplastic elastomer TPV as the rigid material instead of polypropylene.
This is just a small part of the many features of the foaming extruder and the multi-layer extruder. It is hoped that this introduction will give you a little new understanding of the two extruders.
