Rigid PVC does not typically contain any plasticized element, whereas soft PVC has a high plasticizer concentration. Plasticizers come in two different types, primary plasticizers and polymeric plasticizers. Primary plasticizers include phtalates, phosphates and fatty acid compounds. Adipates, azelates of propylene glycol and sebacates are a few of the polymeric plasticizers. To make PVC more flexible, plasticizers like phthalates, adipates and phosphates are used in greater quantity.
Hard or rigid PVC is dense and more resistant to gas and air pressure than the flexible or soft PVC. The density of hard PVC can measure from 1.3 to 1.45 g/cm3 compared to the density of soft PVC, which is 1.1 to 1.35 g/cm3. Due to higher level of density, a product made up of hard PVC lasts longer than the one composed of soft PVC.
Hard PVC is in more demand in the manufacturing sector than the soft PVC because of its stronger thermal, mechanical and chemical resistivity. Soft PVC generally has less utility because it cannot be preserved for a long time due to the excessive application of softeners. However, hard PVC can be preserved for a longer period of time, making it useful for many products.
PVC raw materials are used in the construction sector. Hard PVC is used to make window frames, pipes and borders because it can tolerate bad weather conditions. Soft PVC is used in floors, tubes, edge protection frames and insulation because of its flexibility and resistance to oil, grease and chemicals.
Hard PVC can be recycled and is less hazardous to dispose of than soft PVC because it doesn't contain additional plasticizer concentrations. Soft PVC contains a higher concentration of plasticizer, making it more of a health hazard and difficult to recycle.