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A Brief Introduction to Co-Extrusion

A Brief Introduction to Co-Extrusion

17 March 21

Introduction to Co-extrusion

Here is an introduction to co-extrusion. Co-extrusion involves the process of the formation of an extrudate. In order to understand co-extrusion, it is important to understand what extrudate means. Extrudation is a composition of one or more than one thermoplastics in the melted form to achieve a desired shape or figure.

The process of extrudition is very important in amalgamating different polymers and making a combination for certain applications.   The formed amalgamation then goes directly into a customized die in order to produce desired shapes.

Earlier, the use of co-extrusion started in cast filming whereas, now it has become a complete part of blown films and sheet extrusions.

co-extrusion

Structure of Co-extruded products

The reason behind performing this operation is to produce a laminated form of structure that has layers. Each layer plays an important role in adding to the efficiency of the product.  Since they are co-extruded, they can comprise more than two, and in some cases multiple layers. Each layer has a different function that adds to the functionality and complexity of the extruded structure.

The structure is quite complex when the composition consists of more layers. Although the major functionality is to add abilities to the final product, they can also help in tying different layers that are neighboring to the initial structure which helps in achieving overall compatibility.

Variations in Co-extrusion

It is very common for the co-extruded structure to have more than 5 players. In some cases, co-extrusion that goes parallel is also achievable. The use of separate extruders is necessary for every distinctive polymer that is part of the extrusion process. With the help of two variants, they are separate melted streams of polymers that come together to formulate together.

The feeding block merges into one lamination to the flow of melted polymers. The position right above the die for immediate filling.

This part of the co-extrusion is extremely delicate. It requires total dependability on the thickness of the melted plastics. The melting point of different plastic is different melting hence they help in preventing the intermixing of these layers that need to pass through the die for extrusion.  The flowing rate at which each layer goes through the die is controllable with the help of the feeding block. This process is quite inexpensive and feasible.

On the other hand, alternating methods for achieving co-extrusion are by using complex dies that have complicated build-ups that separate the melting polymers in different compartments. These layers arrange in such a way that helps in merging the plastics in the final product.

Although the flow and viscosity of each layer are controllable, a complicated die build-up can facilitate co-extrusion by making compartments within the die.

Either of these methods is completely legitimate. The only difference is in their cost.  Controlling the viscosity and flow of melted polymers can be the feasible choice when you want to opt for an inexpensive method. On the other hand, making the die that facilitates the classification of melted polymers can get expensive due to their customized dies.

Packaging Polymers in Flexible Packaging

The process of extrusion is quite mainstream.  It provides a film of plastic that contains more than two distinctive layers of polymers. There is no transitional step in between. Later, when laminating two or more two plastics, the plastic needs to be melted separately and then merged together.  As per the lamination process, the plastic films joined together must have a certain thickness for production and handling.

During the co-extrusion process, the layers of each polymer are relatively reedy. A single unit handles the whole structural formation. Every layer that self-supports itself is not a requirement.  It also allows the maximum amount of saving in costing because layers that are flexible save the extra effort of providing durability that is much desirable in this process.

A different extruder melts each different plastic in order to avoid blending in the initial stages. In some cases, an extruder that provides an outcome can also be used as a layer that can help in achieving the final desired product. Sometimes a material passes on to the next extruder to add on more layers but in other cases, it goes directly into the die.

This procedure is highly delicate which requires the presence of each layer separately but in an amalgamated form.  This helps the final product to have the properties of each polymer used in its construction. Co-extrusion helps in creating blown and cast films as well. By using co-extrusion, films can get orientation, lamination, and procession in such a way that they form a single layer of different polymer materials.

What is co-extrusion tubing?

Co-extrusion is a very basic step that takes place in different fields of life. Co-extrusion helps in a lot of medical processes. Although they do not play a role directly, they help in creating co-extruded tools and devices that help in performing medical procedures.

The outcome of a co-extruded product is a single piece that comes into existence after wearing two or more than two materials. Each material requires the use of a different extruder that has melted plastic in it.

Co-extrusion plays a major role in creating many medical devices.   These devices have layers in them.  Co-extrusion tubing often has a flexible outer layer and a hard inner layer.   A medical team can perform complex operations by using tubes that support different medical activities in different patients. This aids in providing ease in such operations.

There are very distinctive three areas that include co-extrusion in multi-layering. They are multi-layer extrusion, wire co-extrusion, and wire coating.

Multi-layer Extrusion

In simple words, multi-layering means adding and combining two or more two layers in order to take advantage of their different properties at the same time. Each layer has its own functionality which adds to the achievement of the final product.

The tubes that are multi-layer provide very chic and efficient solutions to different medical problems. Their design offers solutions for many applications like drug inducement and bonding of tubing layer with the outer environment.

Co-extrusion of Wires

The use of multi-lumen tubing in the medical industry is quite imperative. While using lumens can get expensive, co-extrusion tubing provides an inexpensive method of providing spaces inside the tubing to perform major medical operations. They are quite helpful in making use of wires and cables through co-extrusions. It totally depends on the medical procedure as to what kind of co-extruded wire it needs.

Wire Coating

In the field of medicine, many complex operations take place. There are often times when an operator needs to insert wires in the body like cameras and stents. A wire cannot directly pass into a human body thus the outer layers of the wire need a co-extruded coating of polymers. They facilitate invasive surgeries during operations.

Summary

The co-extrusion process is helping majorly in different fields.   Although it may not directly involve the major process outcomes, they play a major role in creating initial climbing steps that complete the outcome. It is helping in making a product that adds to the functionalities of different products. Thus, they are very helpful.

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