What is PVC?

Polyvinyl chloride (PVC) is the third largest synthetic polymer plastic in the world (after polyethylene and polypropylene), with an annual production of about 40 million tons of PVC. PVC is a polymer formed by the free radical polymerization mechanism of vinyl chloride monomer (VCM) in the presence of initiators such as peroxides and azo compounds or under the action of light or heat. Vinyl chloride homopolymers and vinyl chloride copolymers are collectively referred to as vinyl chloride resins.

PVC was once the world’s largest general-purpose plastic with a wide range of applications. PVC is available in two types: rigid (sometimes abbreviated as RPVC) and soft. Rigid PVC is used for building pipes, doors and windows. It is also used to make plastic bottles, packaging, bank cards or membership cards. Adding plasticizers can make PVC softer and more flexible. It can be used for pipes, cable insulation, flooring, signs, phonograph records, inflatable products and rubber substitutes.

Main Classifications

What are the different types of PVC plastics?
There are many types of PVC, which can be divided into two main categories: rigid PVC and soft PVC. Rigid PVC, also known as UPVC, PVC-U, or unplasticized PVC, is a type of PVC plastic that does not contain plasticizers. In addition, this type of PVC has the lowest compounding content.

Flexible PVC, on the other hand, contains plasticizers such as phthalates, which make it softer and easier to bend. This allows them to be used in the production of wire insulation and flooring in schools, homes, and hospitals. Let’s take a closer look at the different types of PVC plastics.

UPVC (Unplasticized)
At a temperature of 20 degrees Celsius, this type of PVC has a tensile stress of about 52MPa. However, it is used at temperatures up to 60 degrees Celsius. However, it is important to note that the actual temperature limit of UPVC usually depends on various factors, including environmental conditions and stress.

PVC (Plasticized)
This type of PVC contains plasticizers, which makes it more flexible and less rigid. Although it belongs to the category of flexible PVC, it has a higher impact strength. Its flexibility makes it easier to perform plastic extrusion, injection molding, and other plastic production.

Polyvinyl Chloride
PVC-C, also known as chlorinated PVC, has similar properties to unplasticized PVC. However, due to the higher chlorine content, this type of PVC is more heat resistant and can be used at temperatures up to 95 degrees Celsius.

Polyvinyl Chloride
This type of PVC has twice the ultimate tensile strength of UPVC. It is also called oriented PVC, which favors the production of hoop- or circumferentially oriented PVC molecules. The PVC molecules used in this process are generally of the long-chain type.

Polyvinyl Chloride
It is also known as modified PVC and is a type of rigid PVC. It has higher impact resistance, but its ultimate tensile strength, yield stress, and elastic modulus are lower than unplasticized PVC.

Main Uses

PVC profiles
Profiles and profiles are the largest consumption areas of PVC in my country, accounting for about 25% of the total consumption of PVC. They are mainly used to make doors and windows and energy-saving materials, and their application volume is still growing significantly across the country. In developed countries, the market share of plastic doors and windows is also the highest, such as 50% in Germany, 56% in France, and 45% in the United States.

PVC pipes
Among the many PVC products, PVC pipes are the second largest consumption area, accounting for about 20% of its consumption. In my country, PVC pipes were developed earlier than PE pipes and PP pipes, with more varieties, excellent performance, and a wide range of uses, occupying an important position in the market.

PVC film
PVC consumption in the PVC film field ranks third, accounting for about 10%. After PVC is mixed with additives and plasticized, a three-roll or four-roll calender is used to make a transparent or colored film of a specified thickness. The film is processed in this way to become a calendered film. It can also be processed into packaging bags, raincoats, tablecloths, curtains, inflatable toys, etc. by cutting and heat sealing. Wide transparent films can be used for greenhouses, plastic greenhouses and ground films. The biaxially stretched film can be used for shrink packaging due to its heat shrinkage characteristics.

PVC hard materials and sheets
PVC is added with stabilizers, lubricants and fillers. After mixing, it can be extruded into hard pipes, special-shaped pipes and corrugated pipes of various calibers by extruders, which are used as sewer pipes, drinking water pipes, wire casings or stair handrails. The rolled sheets are overlapped and hot pressed to make hard sheets of various thicknesses. The sheets can be cut into the required shapes, and then PVC welding rods are used to weld them with hot air into various chemical-resistant storage tanks, air ducts and containers.

PVC general soft products
Using extruders, it can be extruded into hoses, cables, wires, etc.; using injection molding machines with various molds, it can be made into plastic sandals, soles, slippers, toys, auto parts, etc.

PVC packaging materials
PVC products are mainly used for packaging various containers, films and hard sheets. PVC containers are mainly used to produce mineral water, beverages, and cosmetic bottles, and are also used for packaging refined oils. PVC film can be used to co-extrude with other polymers to produce low-cost laminated products, as well as transparent products with good barrier properties. PVC film can also be used for stretch or heat shrink packaging, and is used to package mattresses, cloth, toys, and industrial goods.

PVC siding and flooring
PVC siding is mainly used to replace aluminum siding. In addition to a part of PVC resin, the remaining components of PVC floor tiles are recycled materials, adhesives, fillers, and other components. They are mainly used on the hard floors of airport terminals and other places.

PVC daily consumer goods
Luggage bags are traditional products made from PVC. PVC is used to make various imitation leathers for luggage bags, sports products such as basketballs, footballs, and rugby. It can also be used to make belts for uniforms and special protective equipment. PVC fabrics for clothing are generally absorbent fabrics (no coating required), such as raincoats, baby pants, imitation leather jackets, and various rain boots. Polyvinyl chloride is used in many sports and entertainment products, such as toys, records and sports equipment. Polyvinyl chloride toys and sports equipment have a large growth rate, and they have an advantage because of their low production cost and easy molding.

PVC coated products
Artificial leather with a backing is made by applying PVC paste on cloth or paper, and then plasticizing it at above 100 ℃. It is also possible to first calender PVC and additives into a film, and then press it with a backing. Artificial leather without a backing is directly calendered into a soft sheet of a certain thickness by a calender, and then pressed with a pattern. Artificial leather can be used to make suitcases, bags, book covers, sofas and car seat cushions, etc., as well as floor leather, which is used as a flooring material for buildings.

PVC foam products
When soft PVC is mixed, an appropriate amount of foaming agent is added to make a sheet, which is foamed into a foam plastic, which can be used as foam slippers, sandals, insoles, and shock-proof cushioning packaging materials. It can also be made into low-foaming hard PVC sheets and profiles based on an extruder, which can replace wood and is a new type of building material.

PVC transparent sheet
PVC is added with impact modifier and organic tin stabilizer, and becomes transparent sheet through mixing, plasticizing and calendering. It can be made into thin-walled transparent containers or used for vacuum blister packaging by thermoforming, and is an excellent packaging material and decorative material.

What are the advantages and disadvantages of PVC plastic?

PVC plastic is widely used in several industries and brings many benefits 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?

Advantages
Affordability: PVC is easy to purchase and is one of the most readily available materials on the market. The availability of PVC also makes it relatively cheap compared to other plastics.

High density: This plastic has a high density. The high density makes it very hard and more resistant to impact deformation than most plastics.

Tensile strength: PVC has excellent tensile strength, which makes it extremely resistant to wear and tear. This makes PVC plastic very durable.

Chemical resistance: Another advantage of PVC plastic is its chemical and alkali resistance. This is due to its amorphous nature.

Disadvantages
While there are many advantages to using PVC for plastic production, there are also some disadvantages. Here are some disadvantages:

Poor thermal stability: Compared to other plastics, PVC has very poor thermal stability, especially when the temperature is relatively high. Therefore, in order to maintain high stability at high temperatures, manufacturers add additives during the production process.

Toxicity: PVC exposed to fire or melted will release fumes that are toxic to human health and may cause environmental degradation.