The Differences Between Calendered and Extruded Vinyl Films

There are two main ways to produce vinyl films: calendering and extrusion. Each of these industrial processes can be used to produce a range of film and sheet products with distinct qualities. As with any manufacturing process, there are advantages and disadvantages to each approach.

What is Calendering?

In calendering, raw materials enter a mixing chamber where they are melted. This molten plastic then moves through a series of heated rollers that compress the material to the desired thickness. Finally, it passes through a series of surface conditioning and cooling rolls, then is wound into custom rolls or cut into sheets.

Calendering Pros and Cons

On the plus side, calendering allows high run rates on films 6 to 60 mils thick. Calendered material typically has higher tensile properties, product uniformity, and unusually close gauge control when compared with extruded films. The added mixing in the process is ideal for highly filled applications and materials, and has the additional advantage that melt degassing occurs in the process. Finally, materials with lower melt temperatures can be used in calendering due to the high pressures used between rollers.

On the downside, calendered products may have issues with pinholes at gauges less than 6 mils, and there may be appearance issues. The rollers used may create surface blemishes and edge buildup on the melt path can create black specs. Also, the sheets are usually less glossy than extruded materials. Calendering is a process that is typically not economically profitable for short production runs.

What is Extrusion?

In extrusion, mixed plastic compound is conveyed through a heated barrel using a spiral shaped screw, converting it into molten plastic. A lip die flattens the mass into a sheet of the desired width and thickness, which then passes through heated embossing rolls that impart a surface finish. The sheet is then trimmed to its final dimension.

Extrusion Pros and Cons

Extrusion offers a number of advantages. Even at thinner gauges, extruded film is pinhole free and has improved “lay flat” qualities. The extrusion process is more flexible, allowing faster changeovers for smaller production runs. The process also delivers better dimensional stability in both machine and cross web directions, and screws can be designed for specific formulations to help improve film characteristics. Finally, the streamlined melt flow reduces black specks.

A disadvantage of extrusion is the requirement for higher melt temperatures. There can also be poor mixing on highly filled formulations. Finally, melt degassing can be a production issue.

Presco Uses Extrusion to Produce Its Presco Engineered Film

Presco compounds and extrudes the flexible vinyl film known as Presco Engineered Film, which is custom formulated to the exact specification of our customers. And in 2017, Presco added Ethylene Vinyl Acetate (EVA) film extrusion to its capabilities as an option for PVC-free manufacturing. To learn about our capabilities, click here.

Follow us on social media for the latest updates in B2B!

Latest

Grocery Store Prepared Meals
Consumers Want More Grocery Store Prepared Meals. How Should Grocers Adapt?
December 6, 2022

The consumer dollar has spoken: the best thing since sliced bread is sliced turkey. A new FMI report, the FMI Power of Foodservice at Retail, seems to show that deli-prepared food purchases are up 9.3% compared to 2019 numbers and up 2.4% year-over-year in unit sales. It’s clear that consumer appetite for grocery store prepared […]

Read More
Robotics in Early Learning Can Be Essential in How Students React to STEM Literacy
December 6, 2022

Early learning robotics can be essential in how students react to STEM literacy and with large gaps In STEM achievement persisting across the U.S., access to technological resources can make a significant impact. K-12 education was disrupted by the COVID-19 pandemic, but the disruption could be mitigated by introducing the latest and innovative technology into […]

Read More
The European Space Agency Lunar Launch Programs and Service Initiatives to Watch in 2023
December 6, 2022

The European Space Agency is making strides in its efforts to commercialize space, with a focus on sustained exploration. What are they doing to achieve this? According to the ESA, it all starts with service initiatives. A recent panel discussion at the Space Tech Expo in Bremen, Germany revealed that the ESA is growing its […]

Read More