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Argotec has the most modern polyurethane film manufacturing facilities in the industry and the full diversity of extrusion technology - the capability and capacity - but also the commitment and expertise to custom engineer TPU films for your most challenging applications.
WHAT IS BLOWN-FILM EXTRUSION
Argotec's blown film extrusion process begins with computerized mixing of virgin resin and any additives needed to control the film production process and properties, along with carefully controlled rates of regrind, if necessary, to reduce customer cost.
The mixture is heated and conveyed through the extruder. The melted material is then pumped, under continuous pressure, through a circular, rotating die (1) that creates a tube of thin polyurethane (TPU) or other polymer. As the warm, extruded material is drawn up several stories by nip rollers (2), the tube is expanded by filling it with air, creating a "bubble" (3) that performs three basic functions:
- The volume and pressure of air "blown" into the tube causes the material to stretch, thereby determining the overall size of the bubble and the width of the finished sheet.
- This same action, in conjunction with the rate at which the bubble is being pulled upward away from the die, determines the thickness of the finished film.
- The bubble begins the air-cooling process while traveling up to the nip rollers.
As the bubble enters the nip rollers it is collapsed into a flat tube (4) and then cools further while it travels back down the outside of the tower (5) to an additional set of rollers (6).
The film next enters the slitter station where one or both sides of the flat tubular film can be slit. Slitting both edges allows the flat tube to be separated into two layers that can each be wound onto their own core. Slitting only one edge allows the flat tube to be wound onto one core as a double wound layer with one "open" edge that can later be opened by the customer to a double width film.
Finally, the finished product is wound onto corrugated or plastic cores (7) and packaged for shipment to the customer.
WHEN TO USE BLOWN FILM
Blown film extrusion has several advantages over flat-die or cast-on-carrier extrusion, the other methods typically used to manufacture polyurethane film and sheet. These include:
- When cost is a factor. Blown film can be the most economical method for producing films from 1-10 mils thick.
- When a carrier or interleaf is not required.
- When consistently flat roll put-up is critical. The rotating die on a blown film extruder distributes any gauge variations evenly across the width of the roll.
- When the high-slip attribute of the processing aid is acceptable or desired.
BLOWN FILM PRODUCT OPTIONS
The product designer, converter or fabricator who determines that blown film extrusion can provide the economies and product characteristics required for their specific application has a variety of product options to specify.
- Thickness: typical film gauge from blown film extrusion ranges from 1 to 10 mils, although Argotec can extrude from 0.8 to 12 mils.
- Width: maximum sheet widths up to 86 inches.
- Length: is a function of the size of the bubble and resulting gauge, up to a maximum roll diameter of 20 inches.
- TPU Polymer: aromatic or aliphatic polyester; aromatic or aliphatic polyether; aromatic or aliphatic polycaprolactone.
- Surface finish: smooth or rough.
- Additive packages: flame resistance; UV resistance; antibacterial; antifungal; lubricant and antiblock packages.
THE ARGOTEC BLOWN FILM LABORATORY TEST LINE
The Argotec lab line can produce thermoplastic film in thicknesses from 0.8 to 12 mils, widths of 6 to 15 inches, and lengths of up to 100 feet. It is used for a variety of key functions:
- Generating short-run film concept samples for customers.
- Testing the processability and physical characteristics of new film formulations.
- Performing preliminary tests of new product offerings from resin suppliers.
In addition to demonstrating Argotec's commitment to R&D, its blown film lab line also enhances the company's ability to engineer polyurethane or other TPE film compounds to a customer's specific application requirements and then test the feasibility of the formulation in advance of a full production run, thus saving the customer significant development costs.
When choosing a specialty film supplier, be sure to consider the entire program. Click on the link below for a review of what should be included in a successful blown-film program.