How do you define plastic - ubiquitous, the most important invention of all times (think about it, it does give competition to wheel and electricity in sheer user friendliness), the biggest hazard for the environment? Whatever it is, it sure can’t be ignored. Not convinced; just look around, chances are that things coming most natural to you are made of plastic or some of its variants.
Now that we have established that plastic is important, one way or other, let’s discuss it more deeply; exactly my endeavor through this series of articles. Through this series of articles I would like to make people aware of different aspects of the colored plastic, colored masterbatches (basic ingredient to impart colors to plastic) , new developments in the field, and most importantly about plastics and environment.
Let’s start with, ‘what is plastic?
Basically plastics are synthetic petroleum derivatives. Their name is derived from the fact that many are malleable, in other words they have the property of plasticity. It can cover many synthetic or semisynthetic polymerization products and are composed of organic condensation or addition polymers. It may contain other substances to improve performance or economics such as color masterbatches, additive masterbatches or for that matter special effects masterbatches.
This brings us to the question, ‘what is masterbatch?’
Masterbatch is a concentrated mixture of pigments and/or additives mixed during a heat process with a carrier resin. Masterbatches allow the processor to color raw polymer economically during the plastics manufacturing process.
Masterbatches are of two major types.
• The pigment master batch to color the plastic.
• The functional additive masterbatch to make the plastic capable of certain performances like making them heat resistant, weather resistant etc.
The exploding demand for colored plastic, thereby color masterbatches, can be gauged by the fact that its demand has grown from just under 90,000 tons in 1990 to nearly half a million tons in 2004.
With growing demand comes the growing concern for quality. Color masterbatches manufacturers and exporters like
RPIndustries make the effort of maintaining every tiny little detail of the compositions of masterbatches and processing conditions in the records. Manufacturers like them factor in the following while formulating masterbatches:
1) Bulk density and specific gravity variations can result if different base ingredients are used. This can lead to a further difference in the end result if gravimetric or volumetric dosers are used at the processor.
2) Formulations will vary depending on whether a supplier is designing a new masterbatch or copying someone else's. It is always best to be involved at the color conception stage where it's possible to optimize formulation choice.
3) Formulations can be different depending on whether they are manually designed or computer generated.
4) Masterbatches may contain different amounts of pigment depending on the pigments strength/price ratio and how well the pigments have been dispersed.
5) A masterbatches ability to distribute (mix) into the polymer will vary due to its viscosity and flow. This varies between suppliers.
6) Processor machine type (size, capacity, screw-type, operating profile) can all influence the performance of the masterbatch.
7) Some masterbatches are weak due to differences in extrusion capabilities.
This brings us to the end of this article. In my next article I will discuss the part nanotechnology can play in enhancing the performance of plastics.
The author……is a chemical engineer and is working in
plastic factory. He is also an Internet enthusiast and has contributed with articles on chemical engineering.
