Introduction: The Thermoplastic material Polyvinyl Chloride which we call PVC in short has become one of the most important plastic materials in today's plastic market being low-cost material and reusable thermoplastic after Polyethylene PVC material has captured the whole plastic market. Synthesized in 1872 by German scientist Eugen Bauman. PVC is made up of its monomer named Vinyl Chloride. 





Types of PVC : 

1. PVC-U (Unplasticised): Hard and rigid with Ultimate tensile stress of about 52Mpa at 20 degree celsius. Resistant to most chemicals.

2. PVC-M (Modified): Rigid as well as extra tough. Low mechanical properties as compared to PVC-U

3. PVC-Plasticised: Less Rigid, High impact strength easy for mfg processes like extrusion, lower mechanical and physical properties as compared to PVC U and PVC M.

4. PVC- C (Chlorinated): Similar properties to that of PVC-U except higher temperature resistance functional upto 95-degree celsius. Ultimate tensile strength of about 15 MPa at 95 degrees.

5. PVC O- (Oriented PVC) : HSPVC: High strength PVC, great contribution in product advancement.


Current Manufacturing Processes in PVC pipe Manufacturing : 


1. Extrusion : 

Extrusion is a process in which the material is molten and passed through a 2D profile so that it will take shape of that 2D profile.

 

..
Observe the figure in which a cylinder is shown, basically the circular cross-section is a 2D profile, and material is passed through that profile and we get the cylinder in 3D. 

PVC is a thermoplastic as well as it is workable upto 95-degree celsius, it is very much suitable to be used for the extrusion process. pipes are manufactured by the Extrusion process. 

2. Injection Moulding : 




As shown in the figure is a simple diagram that shows the flowchart of the Injection molding process.
in this process molten plastic material is passed through the nozzle, this liquid plastic is then passed through the sprue and then enters the mold, after cooling we get the plastic component of the desired shape.   

Basically, the pipe flanges pipe joining parts are quite complex that they can't be manufactured by the extrusion process, so such components are manufactured by the Injection Molding process. The injection molding process is more expensive than that of other processes.


3. Rotational Moulding : 

In this process plastic is in the powdered form, it is kept in the rotating mold, due to the hot inner surface plastic powder melts and takes shape of the desired shape. at the circumference of mold liquid plastic is gathered due to centrifugal force. Once it is cooled we get the desired shape of the component.
This process is generally used for large inspection chambers, and water and septic tanks in polyethylene (PE) or polypropylene (PP).

Following is the figure which shows the working mechanism of Rotational Moulding.


Advantages : 

1. Recycling: PVC material is a thermoplastic material ie PVC can be molten and regains its properties when cooled, due to this property, PVC products, if not used, can be recycled. So PVC is very easy to recycle. which Makes it reliable to be used more and more in the plastic market. The plastic industry has increased in a great extent in such a case recycling PVC, again and again, will be friendly for the environment also cost of PVC and its products will be reduced. 

2. Transport Safety : PVC pipes are bacteria resistant, its very hard for bacteria to breed on PVC as well as it is corrosion resistant which makes its products more durable and reliable. This is the reason why PVC pipes can be used for water transport. 

3. Cost Effective : Due to high demand as well as abundant availability PVC is a very cost-effective option