What is pvc

What is pvc

PVC is the term poly vinyl chloride and refers to the polymer with the following chemical structure: pvc

PVC is a thermoplastic polymer, which, depending on its size, can be flexible (Plasticized PVC, Soft PVC) or hard (Unplasticized, UPVC).

In the present situation, one of the most valuable products of the petrochemical industry is used. More than 50% of PVC made of human construction is used in building. Because PVC is cheaper than other polymeric materials, it can be made with different types of products. .

In recent years, PVC has been a great alternative to building materials, and is being removed due to the long life of the product produced with this highly applied material and the traditional materials that can be produced with PVC.

PVC applications:

Medical sewage pipes

Used profiles for double glazing doors and windows

Wall coverings for auto parts

Household Appliances Electronic Components

Coatings for wire and cable furniture

Door cover and cabinet

Pvc production method:

PVC polymer was used for various polymerization processes, and finally, the resulting polymer was introduced with the same process. The polymerization processes of pvc are:

Suspended polymerization

Emulsion polymerization

Massive polymerization

The various processes of pvc production make the resulting product different in shape and size of the granules, the absorption of softening oils, optical, electrical, physical, mechanical properties as well as applications.

Polyvinyl chloride suspended or PVC-S:

In this method, firstly, water insoluble liquid monomer is spread by strong stirrers completely in water and then by adding an appropriate starter which is soluble in vc, the reaction begins and eventually the particles of the pvc are as large as 20-200 μm Are formed.

The PVC-suspended molecular chains in water are separated from the blue phase by centrifuge systems, gratings and filtration, and after searching and drying, the PVC-S spheroidal and particulate particles are obtained from them as a suitable polymer for the manufacture of electrical products And with transparent artifacts using extrusion and injection processes. The advantage of this method is the ease of transferring the heat generated by the polymerization reaction, which is easily done by the aquatic environment.

Polyvinyl chloride emulsion or PVC-E:

In this method, Ibenda monomers vc water insoluble liquid with water-soluble emulsion water is distributed thoroughly in water by water softeners. Add water soluble starters (often water-soluble peroxides such as calimic sulfate) and adjust the temperature The reaction system begins, and then very fine PVC particles are formed. The PVC dye solution is reconstituted from unreacted monomers under special conditions and under vacuum pressure. The material obtained can be used directly in the coating work-sinking or even as a glue.

The presence of emulsion in Pvc reduces the friction between the polymer and the metal parts of the process machinery, making it easy to produce. In contrast to this, it causes electrical features to drop, a tendency to get the electricity and color of the product. The shape and magnitude of PVC grains in this method are due to the condition of dryers, the detached pvc particles from the blue phase, which can be varied by changing the particle size of the particle size from 2 to 60 microns.

PVC-E is used mostly for the production of artificial leather, wallpaper, gloves.

PVC Properties:

High strength

Resistant to inappropriate weather conditions

Proper processability

Inexpensive

Self-defense

Melting temperature is about 80 ° C

Resistant to U.V.

Density from 0/8 to 1/47 (g / cm3)

Compatibility with old ones

Insoluble in alcohol, hydrocarbons, acetone

Excellent electrical properties

Continuous use at 60 ° C

Resistant to chemicals, oils, weak acids

Soluble in methyl ketone, toluene, nitrobenzene

K-value concept:

Each PVC producer, depending on the final use, produces a special type of polymer that is mutually matched in terms of morphology and molecular mass. In industry, the K-Value, or the viscosity number, represents the molecular weight of PVC It’s working.

In order to measure this index, the viscosity of the PVC solution is determined. The higher this indicator, the higher the molecular weight of the PVC.

The K-Value range is usually between 35 and 80.

Different uses of PVC in K-value:

K-Value Between 55 and 60 for injection

K-Value Between 66 and 68% suitable for wall extrusion, profiles, pipes and …

K-Value between 65 and 71 is suitable for producing flexible parts, cable sheath and …