What Additives used in PVC

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With PVCP grades, a plasticizer is added to give PVC flexibility and elasticity. In combination with the plasticizer, filler is normally included which enhances the mechanical properties, with the added advantage of cost efficiency. As the PVC resin content in PVCP can vary between 30 to 60%, the balance, which is invariably plasticizer and filler, is adjusted to suit. With PVCP, the most important parameters are softness and specific gravity (SG) – the higher the level of filler used the higher the SG will be. The softness is achieved predominantly by altering the level of plasticizer. The specific gravity of PVCP compounds can range from 1.13 to over 2g/cm3. PVC film wholesale Rigid PVC compounds also include the necessary stabilizers and some lubricants – this tends to be far less than with PVCP as the plasticizer also has inherent lubricity. buy pharmaceutical PVC film While stabilization protects the raw material from the heat required to process it, lubricants are also critical to aid processing because PVC has a significant tendency to adhere to metal. It is essential therefore to form a barrier between the metal of the processing equipment and the PVC melt itself. This is achieved by using external lubricants such as paraffin based products and polyethylene waxes. Internal lubricants are also necessary. PVC sheets for folding box These reduce the melt viscosity of the material and so prevent internal friction generating too much heat during compounding and subsequent processing into the final product. The addition of lubricants has a further function in that they control the “fusion” or “gel” time of the material. This is essential to ensure that by the time the PVC compound reaches the end of the processing equipment, the material is sufficiently homogenized to disperse the various additives and hence achieve optimal physical properties.