Polymer Pelletizing Anti-Stick Agents

Benefits

• Prevent agglomeration during cooling, drying, and storage
• Significantly reduced scrap and material loss due to agglomeration
• Non-foaming and low-foaming options
• Melt/ compound harmlessly into polymers during adhesion or molding
• Easier to disperse in water than slurries and stearates
• Remain suspended in process fluids longer than stearates
• Improve plant safety and cleanliness
• Improve end-user processability
• Superior anti-stick properties when compared to stearates
• Also prevent pellets from sticking to drier walls and machinery
• No heavy metals or carcinogenic defoamers
• No effect on hotmelt adhesive performance
• Easily integrated into existing systems

Applications

Supported Materials

While homopolymers typically experience minor tackiness, copolymers (namely polyolefins) and terpolymers are slower to harden (crystalize) in pelletizing processes, requiring an anti-stick agent to prevent sticking and agglomeration of pellets during cooling, drying, and storage. McLube® offers anti-stick agents for a variety of thermoplastic elastomers (TPE) and thermoplastic polyolefins (TPO) like ethylene, propylene, and butene-1 copolymers as well as polyester, polyethylene terephthalate, EVA, styrene-butadiene, and other specialty polymer blends.

Technology

Why Replace Stearates and Powders?

Many different methods are used to limit agglomeration in pelletizing operations, including compounding anti-stick additives into the polymer, tumbling the pellets with anti-stick powders, and integrating stearates and slurries into the system. Tumbling with a polyolefin powder offers limited anti-stick benefits due to incomplete coating of the pellets. Tumbling softer polymers has also been shown to deform pellets and decrease the quality of the batch. Slurries and stearates offer some anti-stick benefits but are notoriously messy, labor-intensive, and difficult to disperse in water baths. Poor dispersion of the anti-sticking additives in slurries and stearates results in inadequate coating of the pellets and significant material loss per batch due to agglomeration. Much of the material loss attributed to HDPE slurries and zinc stearates occurs because pellets far from the stirring apparatus are not coated with anti-stick at all.

In sharp contrast to slurries and stearates, McLube anti-stick coatings are easy to disperse or emulsify in water and require significantly less agitation to remain suspended. Improved integration into water baths and other water-based process fluids ensures our anti-stick agents more effectively coat the maximum number of pellets, drastically reducing material loss due to agglomeration. McLube® anti-stick coatings also do not contain hazardous materials like talc, silica, or heavy metals. To eliminate the foaming issues associated with soap-based stearates, McLube offers low-foaming and non-foaming anti-stick agents for polymer pellets.  Contact McLube® and one of our experienced Technical Representatives will help you seamlessly integrate our superior anti-stick technology into your pelletizing operation.

Methods of System Integration

Anti-sticking agents will be most effective when introduced “upstream” of the steps in your process that experience the most pellet deformation and agglomeration. Where and how the anti-stick agent is introduced will depend on your specific process methods, conditions (namely temperatures), and materials. McLube® anti-stick coatings for polymer pelletizing may be tailored for introduction into cutting water (underwater operations), cooling water, centrifugal driers, or a combination of these methods to prevent sticking wherever it may occur. Introducing our anti-stick agents into cooling water has proven to reduce or eliminate stoppages as a result of sticking in the transport line; tackier materials like butene-1/ethylene copolymers and pellets cut into small, spherical shapes may require introduction of an anti-sticking agent directly to the cutting water or cooling water to prevent agglomeration along the transport line to the drying mechanism.

Centrifugal application, applying the anti-stick coatings with the help of a rotor, increases the uniformity of the anti-stick coating applied to each pellet; however, pelletizers are beginning to switch to conveyor drying methods to eliminate the physical abuse put on pellets by centrifugal drying steps. Customers who have switched to conveyor drying methods still apply our products before the pellets are run onto the belt in order to prevent sticking during storage and shipping.

Contact McLube® today and one of our experienced Technical Representatives will help you eliminate agglomeration and improve the overall efficiency of your pelletizing operation.