subject: Additives Omnipresent In Plastic Processing [print this page] Plastic products are ubiquitous in our modern day life. From the melamine crockery to bakelite switches, plastic products are everywhere around us.
As users, we ask for increasingly better quality in products we use, putting a pressure on the plastic product manufacturers to seek ways for improving the quality of their products, without raising their incurred costs. This makes plastic additives essential to manufacturers.
To say that plastic additives are now being used in every aspect plastic product manufacturing would not be wrong. For example, household products such as crockery and cutlery, made of polymers like polypropylene, are typically injection molded.
Such items do not have a symmetric shape and cant be manufactured by any other production technique.
However, injection molding requires preheating of polymers like ABS, HIPS, Nylon, filled PP etc. for up to 4 hrs and consumes expensive electrical energy.
Also, the manufacturers often have to deal with problems like breakage or poor surface finish, whenever using recycled polymer or fillers.
If the preheating is not done, the moisture present in the polymer can create various surface defects such as blisters and delamination, which are not only aesthetically undesirable but also can also severely reduce the quality of end product.
Besides this, there are problems of poor dispersion of color masterbatches or poor flow rates which harass the manufacturers. These problems come from the variation of Melt Flow Indices (MFI) from virgin polymer to recycled one. Most injection molders agree that using additives for injection molding gives better products and generally enhances productivity.
Similarly, recycling is the buzzword in today's environment conscious plastic industry. Recyclable polymer scrap comes from two sources: domestic or post user and industrial scrap.
In order to successfully recycle this scrap, a recycler has to wash the scrap and shred it down to a more uniform size.
This washed and shredded scrap is then extruded and cut into pellets, which can be reused for making useful objects.
However, this process affects the quality of the polymer in two ways. First, a high quantity of moisture gets entrapped in the polymer during the washing and cleaning process and second, heterogeneous mixing of different polymers reduces the mechanical strength of end product.
Due to moisture, the pellets often lack good surface finish and the reduced strength results in poor physical properties of the products made from such pellets.
While the recyclers can use desiccants to remove moisture either while recycling scrap or while making products from pellets, but the results are not sufficient. Now-a-days, most manufacturers opt for high performance additives for their recycling requirements.
Such additives for plasticrecycling are specifically developed for removing moisture and homogenizing the constituent polymers, improving the strength and aesthetics of the end products.
