Improving the Efficiency and Quality of Polyolefin ExtrusionProcessing Aids for Films

Improving the Efficiency and Quality of Polyolefin Extrusion 2

Experts predict that the extruded plastics market will reach $291 billion by 2026, growing at a compound annual growth rate (CAGR) of 4.7%.¹ An optimized, high-speed polyolefin extrusion system that runs without interruption and produces high-quality films, plastic sheets, molded plastics, and tubing will be critical to achieve this projected growth.

Strong demand for improved plastic quality, higher yields, and increased production

¹Source: https://www.mordorintelligence.com/industry-reports/automotive-belts-and-hoses-market

For years, manufacturers have added extrusion process aids to resins to reduce common extrusion process problems like melt fracture and die buildup. The latest generation of extrusion process aids require smaller amounts to improve extruder efficiency and product quality, which translates into greater opportunities for market growth.

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Types of Polyolefin Processing Challenges

Naturally, manufacturers—especially producers who make extruded blown films and products like tubing, cable jacketing, and pipes—want to avoid processing issues that lead to lost revenue: products that fail inspection, flow line disruptions, or reduced output from downtime.

Melt fracture and extrusion instabilities are two main obstacles manufacturers typically encoun-ter that impact product quality, production rates, and yield.

Melt fracture will limit flow rates

Melt fracture involves stresses in the die and is often resin-related. The melt fracture—caused by extruded material sticking to the die wall and subsequently slipping as pressure builds—results in a jagged surface on the extrudate. This surface defect is also called “sharkskin” due to the regular pattern of ridges in which ruptures appear.

Extrusion Instabilities Will Affect Quality and Limit Output

Die buildup causes one major instability: mate-rial attaches to the extrudate, breaks off, and is carried downstream onto the product, affecting extrudate quality. Surface irregularities can neg-atively affect the product’s aesthetics, as well as optical and mechanical properties. Often, the only solution requires shutting down the extru-sion lines to clean the die of unwanted deposits.

The operational issues manufacturers may expe-rience depends on the type of extruded product. Examples include:

• Blown film: Melt fracture causes visible imperfections and can increase die pressure

• Wire and cabling: Die buildup distorts surface appearance

• Cast film: Die buildup contributes to visible and structural imperfections

• Pipe extrusion: Die buildup leads to visible imperfections and poorer physical properties

• Blow molding: Die buildup negatively impacts the appearance and structural integrity of final products, in addition to cycle time

Improving the Efficiency and Quality of Polyolefin Extrusion

4Improving the Efficiency and Quality of Polyolefin Extrusion

Addressing Extrusion Problems Using Extrusion Process Aids

One simple—though not yet economical—solution used to reduce melt fracture and die buildup involves slowing the extrusion output rate. However, slowing the rate may only reduce (not eliminate) these problems.

A more practical, cost-effective approach is to use a small amount of an extrusion process aid in resin formulations. In this process, fluoropolymers migrate to the metal die surface and deposit a thin layer on walls. The polymer slips through the extruder at a uniform speed, which eliminates melt fracture and reduces die buildup.

Achieving a Smooth Process Throughput

Extrusion process aids reduce friction by coating the inside of dies with a nonstick coating. This coating allows the extrusion to flow more freely and rapidly through the die opening, which eliminates sharkskin and enables higher production rates.

Reduced Die Buildup and Downtime

The process of cleaning die buildup causes significant downtime during the production process. A suitable extrusion process aid should have nonstick properties that prevent low molecular weight fractions from accumulating at the die exit, which is a major cause of die buildup.

Faster Product Changeover

Adding an extrusion process aid to a resin melt stream produces a slippery coating on the die surface, which makes for a faster transition between products.

The bottom-line benefits of using extrusion process aids for extrusion

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Extrusion Process Aids: Working Smarter, Not HarderAdding extrusion process aids to the resin melt stream renews and replenishes the slippery coating on the die surface continuously during the extrusion process for many products. Below are some of the most common applications that benefit from extrusion process aids.

Blown Film Applications

Extrusion process aids prevent sharkskin melt fracture and help achieve a smooth, clear film with a high-gloss finish. Combining the properties of extrusion process aids with improved production rates, easier product transitions, and reduced yield loss leads to higher quality film at a lower cost.

Extruded Shapes

Extrusion process aids help keep the die face clean by reducing die buildup in the production of extruded shapes like tubing, cable jacketing, and piping. Cleaner dies reduce imperfections and the potential for product scrap or rework. They also lengthen intervals between downtimes required for cleaning. Smoother extrusion conditions lead to higher throughput and improved surface finish on extruded products.

Fibers and Monofilaments

Extrusion process aids reduce die buildup and resulting strand breakage. Improved throughput, faster winding speeds, and less downtime lead to higher yields and profitability.

6Improving the Efficiency and Quality of Polyolefin Extrusion

Next generation extrusion process aids help to transform film production by addressing common pitfalls in the extrusion manufacturing process: throughput, downtime, and scrap.

They offer more consistent performance over a broader range of processing conditions and minimize discoloration caused by thermal breakdown. They also reduce olfactory effects during processing and in final products—all at lower concentrations than older extrusion process aid technology. Viton™ FreeFlow™—the latest generation extrusion process aid—contacts and coats die surfaces more efficiently than other products on the market, so manufacturers need fewer extrusion process aids to achieve the same results.

Introducing the Next Generation of Extrusion Process Aids

The Viton™ FreeFlow™ Z family of extrusion process aids work with some of the most demanding and challenging resins under a broad range of processing conditions and formulations. Like previous-generation extrusion process aids from Chemours, Viton™ FreeFlow™ Z100, Z110, Z200, and Z210 extrusion process aids offer improved thermal stability. Greater tolerances enable extruders to push the manufacturing envelope to broader temperatures for increased flexibility. Also, the efficiency of Viton™ FreeFlow™ extrusion process aids helps to maximize output.

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The information set forth herein is furnished free of charge and based on technical data that Chemours believes to be reliable. Chemours makes no warranties, express or implied, and assumes no liability in connection with any use of this information. Nothing herein is to be taken as a license to operate under or a recommendation to infringe on any patents or trademarks.

©2019 The Chemours Company FC, LLC. Viton™ FreeFlow™ and any associated logos are trademarks or copyrights of The Chemours Company FC, LLC. Chemours™ and the Chemours logo are trademarks of The Chemours Company.

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We can help you to get to new products faster and better from your first phase of development to testing and inspecting by suggesting the best ways.

For more information, visit Viton.com or call one of our experts:

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With Viton™ FreeFlow™ extrusion process aids, you can do more with less.

When it comes to polyolefin manufacturing and processing, Viton™ FreeFlow™ extrusion process aids increase the flow of ideas. With lower dosage requirements than competitive products by at least a factor of two to three,² manufacturers and processors get the same or even higher throughput with the highest product quality—all while lowering operating costs and reducing waste. And, because Viton™ FreeFlow™ extrusion process aids have fewer negative reactions with other additives, customers can rely on them to deliver consistently efficient performance throughout their operations.

Why Viton™ FreeFlow™ extrusion process aids?

• Faster startup by eliminating melt fracture faster than other extrusion process aids

• More cost-effective production by increasing output and reducing waste

• Produces clear, high-quality film by improving surface finish; film is smoother at any thickness, and pipe is stronger

• Longer production run times and prolonged equipment life by reducing die buildup caused by other additives, enabling them to operate at lower pressures

• Performs extremely well in the presence of other additives, reducing the need to increase dosage and costs

About Viton™ FreeFlow™ Extrusion Process Aids

Our team of experts in Viton™ FreeFlow™ extrusion process aids collaborates with customers to identify the right grade to meet needs and achieve peak component performance.

Peace of mind with a partner you can trust

²Source: https://www.marketsandmarkets.com/PressReleases/extruded-plastic.asp