PVC is one of the most versatile plastics in the world and is used in several industries. As one of the most popular thermoplastics, PVC plastic is durable and economical.
In this article we discuss important things you need to know about PVC plastic: what it is, its applications, advantages, disadvantages, types and properties.
What is PVC plastic?
PVC, also called polyvinyl chloride, consists mainly of PVC resin and varying proportions of additives. These additives include lubricants, pigments, processing aids, stabilizers and plasticizers.
PVC is the third most common material in the world and is very robust and durable. Furthermore, it is durable and lightweight, making it the ideal material for plumbing and construction work.
PVC is produced through a polymerization reaction with vinyl chloride monomer and is amorphous. This makes it easier to combine with other substances, chemicals and additives. Furthermore, resin, a basic component in the production of PVC, is a brittle, solid and white material. The addition of additives gives PVC many desirable properties, including elasticity, flexibility, microprevention, fire resistance and anti-fog.
PVC material properties
Due to its diverse properties, PVC is the third most used material in the world. Here are some of these properties of PVC.
- Oil and grease resistance
- Affordable and economical solution
- Excellent tensile strength
- Flame retardant and self-extinguishing
- Durable and withstands adverse weather conditions
- Shock and corrosion resistant
- PVC plastic is lightweight.
- Wear and abrasion resistant
- High vapor barrier and dielectric strength
- Excellent resistance to all inorganic chemicals
- More flexible than other plastics
What different types of PVC plastics are there?
There are different types of PVC, which are divided into two broad categories: rigid and flexible. Rigid PVC, also known as UPVC, PVC-U or unplasticized PVC, is a PVC plastic that does not contain plasticizers. Additionally, it contains the least amount of mixed ingredients.
Flexible PVC, on the other hand, contains plasticizers like phthalates, making it softer and more likely to bend. This makes it used in the production of insulators for electrical cables and flooring in schools, homes and hospitals. Let's look at the different types of PVC plastic in more detail.
UPVC (without plasticizer)
At a temperature of 20 degrees Celsius, this PVC has a tensile stress of approximately 52 MPa. However, it can be used and deployed at temperatures up to 60 degrees Celsius. However, it is important to note that the actual temperature limit of UPVC often depends on several factors, including environmental conditions and load.
PVC (plasticized)
This type of PVC contains plasticizers, which makes it more flexible and less rigid. Although it belongs to the flexible PVC category, this PVC has high impact resistance. Its flexibility facilitates plastic extrusion, injection molding and other plastic production.
On the other hand, this type of PVC has lower temperature resistance and lower chemical resistance. Furthermore, this type of PVC has lower tensile strength compared to UPVC.
PVC-M
It is also known as modified PVC and falls into the category of rigid materials. It is very resistant to impact, but its tensile strength, yield strength and modulus of elasticity are lower than those of unplasticized PVC.
However, it should be noted that the amount and type of modifier used in the production of PVC-M plays an important role in its properties.
PVC-C
PVC-C, also known as chlorinated PVC, has properties similar to those of unplasticized PVC. However, due to the high chlorine content, this type of PVC is more resistant to temperature. Can be used at temperatures up to 95 degrees Celsius.
Like UPVC, PVC-C has a tensile strength of 15 MPa at 80 degrees Celsius and maximum tension at 20 degrees Celsius.
PVC-O
This type of PVC offers twice the tensile strength of UPVC. Also called oriented PVC, it favors a process that aligns the PVC molecules in a circumferential direction. The PVC molecules used in this process are often long chain.
When aligned circumferentially, PVC-O has a tensile strength of 90 MPa and an elastic modulus of 4,000 MPa. This allows it to be used in various sectors, such as the production of pressure tubes, films, carbonated beverage bottles, high-resistance garbage bags, etc.
Different types of processes suitable for PVC plastic processing
Different processes are suitable for processing PVC plastic. Three common methods are listed below.
CNC processing
Using a CNC machine is one of the most popular ways to make PVC parts. This is due to the ease with which the machine cuts the material. PVC is naturally abrasive and corrosive. Therefore, using a CNC machine with a non-corrosion resistant cutter would result in wear and deterioration of the cutter over time.
Common PVC processing methods using CNC include milling and turning.
CNC milling
This PVC machining process is ideal for producing prototypes or complex parts. This is a process in which material is gradually removed from the part. This uses a computer-controlled multipoint tool that cuts the workpiece. This process is ideal if you have a complex PVC part shape as it offers precision and accuracy.
CNC turning
This PVC plastic machining process, called subtraction machining, is different from CNC milling. This involves holding and rotating a large piece of PVC plastic while a tool is pressed against the piece. This tool helps to shape the part by removing material until it reaches the desired cylindrical shape.
Machining PVC plastics using CNC turning is often faster, making it an ideal process for producing products with short lead times or low volumes. The operations used in this process include drilling, grooving, boring, cutting, grooving and knurling.
Injection molding
Injection molding is another way to produce PVC plastics. However, unlike most plastics, the presence of chlorine in PVC makes the process a little more complicated. When melted, chlorine releases a toxic gas that is also corrosive and, as PVC contains this element, it does the same when melted. Furthermore, the mold used during the process must be resistant to corrosion. Therefore, chrome materials or stainless steel are ideal for the process.
3D printing
Although not the preferred method, 3D printing is another way for manufacturers to produce PVC plastic. Due to the corrosive nature of PVC plastic, this process is not often used by manufacturers.
Producing PVC plastic for a long period of time using the 3D printing process may affect the functionality of the 3D printing device. This is why most manufacturers prefer the other two PVC production methods while using 3D printing to produce PLA and ABS plastics.
What are the advantages and disadvantages of PVC plastic?
PVC plastic is widely used in many industries and offers several advantages to these industries. However, like most materials used in production, PVC plastic has its advantages and disadvantages. So what are the advantages and disadvantages of PVC plastic?
Benefits
Economical: PVC is easy to obtain, making it one of the most readily available materials on the market. Due to its easy availability, it is also relatively cheap compared to other plastics.
High density : This plastic has high density. Its density makes it very hard, allowing it to resist impact deformation better than most plastics.
Tensile strength : PVC has excellent tensile strength and is therefore also resistant to abrasion and wear. This makes PVC plastic very durable.
Chemical resistance : Another advantage of PVC plastic is its resistance to chemicals and alkalis. This is due to its amorphous nature.
Disadvantages
Although there are numerous advantages to using PVC to produce plastic, there are also disadvantages. Here are some of the disadvantages:
Poor thermal stability : The thermal stability of PVC is very low compared to other plastics. This is particularly true when the temperature is relatively high. To achieve high stability at high temperatures, manufacturers add additives to PVC during production.
toxicity : When in contact with fire or when melted, PVC produces vapors that are harmful to health and can harm the environment.
Tips for processing PVC parts
Many factors must be taken into consideration when machining PVC parts. Here you will find useful tips that will help improve the quality of PVC machining parts.
Use the correct cutting tool
When working with PVC, using the right tools is crucial. PVC is more prone to corrosion. Therefore, it is necessary to process it with a corrosion-resistant cutting tool such as stainless steel. This would help improve the accuracy and safety of the cutting process.
Configuration Considerations
Your workspace setup also plays an important role when working with PVC. Factors to consider include machining speed, bite angle, number of teeth, friction and pressure. Note that lower speed and force are ideal for machining PVC parts.
Avoid contamination
Contamination is a serious concern when machining PVC parts, especially when the part is used in aerospace and medical applications. One way to do this is to immediately remove chips from machined parts and use coolant appropriately.
Drilling and milling
When CNC milling PVC parts, it is ideal to use a high shear or high positive geometry cutter for facing. When CNC drilling, however, it is best to apply little downward pressure and use a slow to medium speed. Also, when drilling holes about ¼ inch or larger, choose drill bits or flat bits designed for drilling through PVC plastics.
PVC plastic applications
Polyvinyl chloride is one of the most versatile plastics in the world and has a wide range of applications. Its application covers various sectors, from construction to healthcare and electronics. Below are important sectors and the use of PVC plastics in the world today.
Health care
The production of PVC disposable items is cost-effective in the healthcare sector. Some notable examples of the application of PVC plastic in the healthcare sector include the production of blood bags and infusion set containers. Other examples include blood and plasma transfusion sets, catheters and cannulas, blood vessels for artificial kidneys, and endotracheal tubes. PVC is also used to make unbreakable bottles, jars, and surgical and examination gloves.
Auto Industry
The automotive sector also benefits from the cost efficiency and high-performance properties of PVC plastic. Research shows that producing automotive parts from materials other than PVC increases the production cost per part by 20-100%.
Notable examples of PVC plastic in the automotive industry include the manufacture of sun visors, seat covers, and underbody protection. Other examples include fenders, interior door panels and pockets, and wiring harnesses in cars.
electronics
PVC's desirable properties, ranging from flexibility, flame retardancy, and ease of installation, make it ideal for use in the electronics industry. A notable example is its use as a cable insulator. PVC cables are more durable and will not crack or harden over time.
Sportive articles
PVC is used in the sports sector in the construction of sports facilities. It is used on floors, roofs, pipes and seats in sports centers. Other uses of PVC in sports include the production of clothing, footwear and equipment that athletes wear on the field where they compete.
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University Degree
PVC is a very important plastic due to its use in many industries and its beneficial properties. However, there are four types of PVC: UPVC, PVC, PVC-O and PVC-C. These types have their strengths and weaknesses. Therefore, knowing its properties will help you make the right manufacturing decisions.
Common questions
Is PVC plastic toxic?
PVC often contains toxic additives such as phthalates. Furthermore, the chlorine component of PVC decomposes at high temperatures and releases toxic vapors that are harmful to health. Symptoms of inhaling these vapors include dizziness, headaches and drowsiness.
Is PVC a hard or soft plastic?
PVC can be hard or soft. For this reason, there are two categories of this plastic material: flexible and rigid. However, the nature of PVC depends on the quantity and type of additives used in its production.
