Most common manufacturing applications are Synthetic Leather (car upholstery, bags, shoes etc.), vinyl coated and linoleum flooring, vinyl coated wallpaper, laminated sheets (special films, belts, tarpaulins) and foam products.
Polyvinyl-chloride (PVC) is a thermoplastic and is mixed to additives which improve its properties and enable it to be processed more easily
Most common major additives are:
plasticizers to provide elasticity i.e. DOP (Dioctyl Phthalate)
stabilizers to prevent degradation i.e. PB salts
lubricants (solvents) to prevent plugging on cylinders of the calendering machine
charges i.e. silicium
pigments i.e. anthraquinones
Typical formulation : PLASTICIZERS : 50%
SOLVENTS : 48%
OTHERS : 2%
The emulsion (polymer + additives) is spread coated and heat cured or calenderized in ovens. PVC emulsion is fed to ovens with successive steps of curing/calendering and cooling sections. Gas is extracted from curing/calendering sections and cooling sections.
Exit gas from curing ovens (180 – 150 °C) which has been directly or indirectly heated.
Depending upon formulation, 500 to 5,000 mg/m³ of plasticizers are present in the exhaust gas. Solvents and other products are also entrained.
As an average, industrial sites regulations specify a maximum emission of 20 mg/m³ of plasticisers ( = invisible ), or 50 mg/m³ total carbon, or an odour related limit. More stringent levels, e.g. 2 mg/m3 of DOP plasticiser are now sought.
Recovered plasticizer and solvent could be re-used.