All about Polyvinyl Chloride (PVC)
Polyvinyl chloride, or PVC for short, is one of the most common thermoplastic polymers. Inherently, PVC is white and has a very dry and brittle nature. In terms of antiquity, PVC has a longer history than most other polymers. The polymer first appeared in 1872 and was commercially produced in 1920 by the renowned company B.F. Goodrich. In general, the introduction of most other common polymers dates back to the 1940s and 1950s. The manufacturing industry is considered to be the main hotbed of PVC, but it is also used in the production of medical supplies and fibers used in clothing.
Polyvinyl chloride is produced in two general forms: dry and brittle (RPVC or UPVC) or flexible plastic. Soft and flexible PVC, or regular PVC, actually react better to bending due to the addition of plasticizers such as phthalates (typically DINP). This type of PVC is mainly used in the construction industry to insulate electrical wires or to produce flooring for homes, schools, hospitals and all places where having a sterile environment is a top priority. Also, in some cases, this type of PVC is used as a substitute for rubber. Dry PVC is mostly used in the production of water and sewage pipes.
Some of the most prominent characteristics of PVC are relatively low price, high resistance to environmental factors, chemicals and bases, high hardness and excellent tensile strength.
What is the reason for the popularity of polyvinyl chloride?
Dry PVC, as
a plastic, has a very high density, which makes it a hard and strong plastic.
Also, due to its high availability, cheapness and long life, PVC is an ideal
option for common construction applications.
PVC and 3D printing
In the article related to 3D printing, it was mentioned that one of the major
disadvantages of 3D printing is the lack of support for the full range of
polymeric materials. Although this spectrum is constantly expanding, ABS and
PLA (polylactic acid) are still the predominant plastics in 3D printing.
The biggest challenge facing the use of PVC in 3D printing stems from its erosive nature, which severely overshadows the longevity of the printer’s internal components. So far, some efforts have been made to make nozzles suitable for PVC, but none of them have been fruitful.
PVC and CNC machining
PVC can be cut into CNC machines. However, naturally all the experts of these machines have noticed the effect of PVC erosion on the blade of the car. In fact, if the blade is not made of stainless steel or corrosion-resistant metal, it will corrode a lot over time due to the corrosive nature of PVC.
PVC and plastic injection machine
This polymer, like other polymers, can be used in the injection molding process. However, the presence of chlorine in the structure of the material complicates the process. This is because molten PVC emits a toxic, corrosive gas. Naturally, the host workshops of these machines must be equipped with a proper ventilation system. It is also necessary to use corrosion-resistant materials such as stainless steel or chrome-plated materials in the mold structure. The shrinkage and shrinkage of PVC in the injection process will be equal to 1 to 2 percent, and of course will vary depending on the material hardness, gate dimensions, melting temperature, mold thickness, mold temperature and the percentage and type of additives.
Is PVC toxic?
Because PVC releases hydrogen chloride vapor during combustion, it can be considered a serious health threat. Electrical wires with non-PVC insulation are commonly used in applications where the risk of fire is high. These vapors are also released during the melting of the material, and as a result, the process of production and use of PVC must be supervised and performed with complete care.
Advantages of PVC
Compared to other polymers, it has a very high density (relative density of about 1/4) and is therefore very hard and resistant to deformation. It is readily available and therefore relatively inexpensive. Dry PVC has a very high tensile strength. It has very good resistance to chemicals and bases.
Disadvantages of PVC
It has very poor thermal stability. Therefore, stabilizing additives are usually used in the production process at high temperatures. It releases toxic fumes when burned or melted.
Technical characteristics of PVC
The properties of PVC are as follows:
Technical name: polyvinyl chloride
Chemical formula: C2H3CI) n)
Thermal bending temperature: 92 ° C
Melting point: 100-260 ° C
- Soft PVC: 6/9 to 25 MPA
- Hard PVC: 34 to 62 MPA
Relative density: 1/35 – 1/45
The last word
Despite the shortcomings mentioned, polyvinyl chloride is considered to be an extremely useful polymer overall. Its unique properties have made PVC an almost invaluable option in construction projects. If you are looking to produce PVC products PTN is proud to announce its readiness to provide any advice, PVC injection machines and related accessories such as PVC mixers. Please contact us if you need more information or any advice on producing PVC products.