Extrusion process of conductive silica gel tube

The instructions for most diverting silicone tubes include a drawing showing the material, dimensions, and tolerances of the tube. For single-cavity catheters, drawings typically include two of the following three dimensions: inside diameter (ID), outside diameter (OD), and tube wall thickness, along with corresponding tolerances. The length and tolerance of the conduit shall be indicated in addition to the winding of the conduit into the spool and the continuous length.

Packaging requirements, sampling methods and cleaning requirements for pipe dimensional tolerance inspection and cleaning requirements may also be indicated in the instructions, such as "pipe surface does not contact dirt and grease". Few instructions also describe conduit characteristics or conduit processing parameters.

Therefore, both extrusion pipe suppliers and OEM manufacturers should understand the importance of the extrusion process and its parameters for different pipeline processing materials.

Extrusion and degradation

In the high-end diagnostic and therapeutic catheter market, the flow of silicone tube processing technology is very important. Market pressure has prompted catheter manufacturers to design smaller, thinner devices with thinner tube walls.

Applications for these tubes include: high-pressure catheters, angiogenesis catheters and stent delivery catheters, as well as balloon tubes for medical balloons, particularly for high-pressure angioplasty and stent delivery.

In addition, it includes catheters inserted or inserted into the human body, as well as other products whose mechanical, physical, chemical, electrical or thermal properties are critical to the function of the instrument.

The degradation in the extrusion process will have a great impact on the characteristics of the conductive silica gel tube. A polymer is a macromolecular component whose unique application properties depend on the molecular size or molecular weight. The process of breaking down these macromolecules is called degradation.

The degradation of polymer will change the tensile strength, brittleness, elasticity and chroma of the pipeline to some extent. In order to understand the degradation process of polymers, it is necessary to understand the various interactions that occur during extrusion.

There are many reasons for degradation during extrusion.

Improper drying or overheating of the material (i.e. the temperature at which the polymer melts) can lead to degradation.

Too much material shear (i.e., too high screw speed or improper screw design) or too long polymer melting time (i.e., too long residence time) are also causes of material degradation.

The main reason for the change in polymer properties is that these factors change the chemical composition of the polymer. Some polymers, such as polyethylene terephthalate (PET), are sensitive to processing parameters and easily degrade, while others, such as polyethylene, are well tolerated.

Degradation causes most polymers to become brittle, reducing tensile strength and shortening the service life of the product.

Another cause of degradation during extrusion is multiple melting.

For example:

Some conductive silicone tube processing materials must be premixed. In other words, the substrate is first mixed with other materials such as colorants, impervious ray fillers, stabilizers or processing AIDS. To ensure that these ingredients are fully dispersed, the premixing process usually requires a separate extrusion operation.

This operation will cause the material to again cause accumulated heat and cumulative shear outside of the tube extrusion process.

Improper operation at any step can lead to catheter degradation.