Polyester Films for Medical Device Applications

The digital card market continues to evolve and is an ever increasing opportunity for digital printers of all types.  This Tek Tip will talk about the changing marketplace in regards to the printing, processing, and films used to make digital cards.

Markets

Plastic substrates have very different handling and printing characteristics when compared to paper products. If you are not familiar with printing on non-paper substrates please take note of the following:
• Plastics will not absorb fluids like paper.
• They restrict the flow of air and other gases between sheets of a stack.
• All plastics are not the same and will vary in ink receptivity and adhesion.
• Most plastics will attract and hold a static charge much easier than paper.
• Plastics generally are more expensive than paper products.

¹Density (D) -The mass (or weight) per unit volume of a material at a given
temperature. Typical units are:
• grams per cubic centimeter (g/cc or g/cm3)
• kilograms per cubic meter (kg/m3)
• pounds per cubic foot (lb/cu ft or lb/ft3)
• pounds per cubic inch (lb/cu in or lb/in3)

Specific Gravity (sp gr) - AKA relative density. The ratio of the density of a material at a given temperature to the density of an equal volume of water at the same temperature. Units = none.

Occasionally a specification for a particular product will come to us that is obviously written using values from a data sheet supplied by us or our suppliers. These values have little meaning as far as a guide to manufacturing the product and here’s why:

Polycarbonate films are commonly used in a wide variety of graphic applications including labels, switch overlays signage and nameplates. In most of these applications the film is decorated on one or both sides, die cut and then fixed in the final application either by mechanical means or with a pressure sensitive adhesive. In the majority of these applications the film remains flat and performs very well.

Environmental Considerations:

Many polyester films are coated or treated on one or both sides to enhance certain properties such as ink/coating adhesion, slip, static dissipation, etc. This coating/treatment will often have properties that are quite different than the base film which is why they work--an adhesion promoting pretreatment provides much better ink adhesion than untreated polyester for instance. The beneficial properties that these treatments provide do not come without a cost.