By Shell Polymers on Dec 19, 2021
With plastic being a ubiquitous material in today’s market, it’s more important than ever to ensure it’s high quality. However, quality in the world of polyethylene has to do with more than just the resin. Polymer testing, as well as the standards to which suppliers hold themselves and the processes they put in place through every stage of the resin’s lifecycle — from creation to delivery — determines quality. Let’s look at what suppliers can do to ensure that level of quality from the very beginning:
The benefits of quality control during the plastic resin manufacturing process
Simply put, proper quality control and polymer testing ensures product quality. Quality control is an important step at all times in the plastic resin manufacturing process, but doubly so when a converter changes suppliers. One of the biggest concerns we’ve heard from converters about changing suppliers is the potential for inconsistencies between their typical resin supply and what they get from a new polymer supplier. When changing suppliers, in-depth material analysis on the supplier side can provide a side-by-side comparison of the old and new supply.
Likewise, this in-depth polymer analysis can help verify new or iterated production processes like the ones our Polymer Pros will help converters with. Working alongside converters, Shell Polymers can optimize production processes for converters so that their products are made as effectively as possible. These tweaks and adjustments in standard processes can lead to positive changes in product performance, as long as the material is not impacted.
Quality control tests can also help ensure compliance with specifications on the converter end, ensuring consistent performance in the finished product. But that’s not all that can be done through polymer characterization. In fact, Shell Polymers can work alongside converters to review products and see, for example, why one type of plastic packaging is preferred over another. When you combine all of the benefits that come with quality standards and polymer testing, it’s clear that converters can gain much from working with a quality-focused supplier. But how much of this is truly necessary?
The need for quality standards and testing
To ensure high-quality polyethylene that satisfies converters and brand owners alike, analysis and testing is a must. That’s because they can help identify quality issues, validate the material, and ensure specification compliance. Early spotting of these issues, that can often lead to product performance problems, and addressing them can only be done with proper and in-depth analysis.
There are measures we are taking to ensure lot-to-lot consistency, one of the most important aspects for a converter in addition to product quality. Inconsistent lots can lead to production hiccups that decrease production efficiency as converters have to adjust their lines for resin changes. These changes can also lead to products that fail to meet customer expectations, and ultimately hurt the bottom line.
Our state-of-the-art process control is another piece of the high-quality resin puzzle. Through measures such as automation and online analyzers, our team is able to maintain consistent, on-specification products for our customers. This analysis goes beyond a one-time check for resin quality. Instead, it’s an ongoing process where team members can check and adjust resin production in real-time. This is a major shift from the typical process of periodically sampling resin and adjusting based on those timeframes. With real-time tracking, analyzing, and adjusting, we are able to maintain a high level of resin consistency.
Caring about quality, every step of the way
Quality starts at the pellet level and at Shell Polymers and we begin our polymer testing there as well. We analyze pellets at the molecular level to ensure they meet the standards expected. The analytical lab is also where we can troubleshoot in real time if any issues arise in the plastic resin manufacturing process, finding the answers to quality issues our customers may have before it affects their production.
We also work with converters to ensure our polyethylene works for their specific needs, and we do that through our application hall. It is an 86,000-square-foot lab that houses commercial-scale, state-of-the-art equipment. With it, we can make parts to qualify resin and verify that it functions well in processing equipment. This saves converters time and money, as they don’t have to test resin on their own machines.
Logistics isn’t always included in the quality conversation, but it’s actually a key component when it comes to ensuring high-quality resin. From a logistics standpoint, our owned-and-operated SIT (storage in transit) yard has a built-in transloader facility to minimize touch points. The rail cars in our fleet are epoxy coated and vented to help to avoid condensation on resin. Plus, our modern railcar de-heeling and wash facility helps to ensure that every car is properly cleaned between resin batches.
Polymer testing at the micro level
Our attention to detail goes to the micro level with the use of our elutriator, which removes dust, fines, and angel hair. These micro-nuisances can slow down production and ruin products if gone untreated, and angel hairs are particularly problematic when it comes to production.
Sometimes called streamers or snakeskin, angel hairs are created when pellets are transferred at high velocities through a piping system. The heat generated from the friction between the pellets and the pipe surface causes the pellets to warm to their softening point. At this temperature, part of the pellet softens and smears on the interior walls of the piping where it almost instantly solidifies again, forming a snakeskin or angel hair pasta shape. This material can plug the filters in a conveying system and even get into the feed material, stopping production.
To avoid these issues, it’s important to take care when conveying resin from silos. Too many 90° elbows will cause resin to develop angel hair. Similarly, if pellets are transported at high velocity in the air conveying system, there is a high probability of causing material attrition which generates angel hair. Reducing these issues will not only cut down on angel hair generation, but costly shutdowns caused by blockages and other upstream issues. That’s why our conveying systems have been designed with optimal routing, gentle bends, and proper velocities.
From polymer analysis to angel hair reduction, there is an entire spectrum of quality-related issues to be aware of. This work should never fall solely on the converter’s shoulders. That’s why Shell Polymers will work alongside converters to test product quality and ensure material specifications every step of the way.