Even if you haven’t previously used a protective film for your own application, you are probably familiar with their presence on many of the products that you purchase every day. By now, you may have actually come to expect to find a protective film on every new i-Something, TV, computer monitor, or major appliance that you purchase. Chances are that your customers also expect to find that magical protective film on your products.
In their simplest form, a temporary surface protection film is a thickness of plastic coated with a thickness of a specialized pressure sensitive adhesive (PSA). A key word when describing protective film adhesives is “temporary.” By design, a temporary surface protection film is not intended to be left on a surface indefinitely. We have all experienced the irritation of trying to remove a supposedly temporary price tag from a new gizmo and the tag tore into strips and/or left a gooey residue behind. That is quite undesirable in a protective film. Read How to Select a Protective Film to avoid having that happen with your protective film.
The most common plastic types used in protective films are:
LDPE (low density polyethylene),
Co-Ex (co-extruded low density polyethylene),
PVC (polyvinyl chloride).
PVC is typically a bit more expensive and is used in special applications, such as metal forming and exterior window protection where the film will be exposed to sunlight for up to a year. LDPE that has been treated with UV inhibitors can also be used for exterior applications. To avoid problems, do not use an interior-rated film on exterior applications. Film thickness is normally described as the combined thickness of the plastic and that of the adhesive. In the USA, film is measured in thousands of an inch, or mils. (This is not the same as millimeters.) Typical film thicknesses range from 1 mil to 6 mil, occasionally higher. The thicker the film, the more protection it offers against abrasions, scratching, etc. Thicker films tend to be more rigid and can be more difficult to apply to contoured surfaces.
Adhesive type is also an important consideration. Textured surfaces usually require thicker and softer adhesives. If the adhesive is just contacting the “peaks” of the surface, it may be touching less than 5% of the total surface area and be prone to falling off the surface. Adhesives for textured surfaces also tend to be higher in tack value.
LDPE, or low-density polyethylene, is the most common type of protective film. It is made from polyethylene, which is the most common type of plastic. As you might guess from the name, there is also a high-density version of polyethylene (HDPE), which is heavier, less flexible, and less elastic—and therefore, not as useful for making protective film. LDPE film comes in a variety of types, which allows it to be used for many different applications.
COEX, or Co-Ex LDPE, is short for co-extruded low-density polyethylene. Co-extrusion means that two or more layers of plastic are created simultaneously and formed together into a single sheet of film. For example, one common co-ex combines a layer of black plastic with a top layer of white plastic. This allows you to take advantage of the different characteristics of each layer, such as combining UV reflection (white) with UV absorption (black) to provide better overall UV protection {link to post on UV & Protective Film}.
PVC, or polyvinyl chloride, is perhaps the best-known type of plastic. PVC film is very elastic and has a slick surface, which makes it ideal for many metal forming applications, among other uses.
PP, or polypropylene, is a type of plastic useful for high-heat applications. It is dimensionally stable, which means it holds its shape and size and does not stretch like PVC films.
PO, or polyolefin, is a plastic film used on some painted metal surfaces and acrylic glass applications.
Paper can also be used as a surface protection film. Paper films are dimensionally stable and can absorb some impacts.
The different types of protective film can come in different thicknesses and with different types of adhesives and tack levels. The numerous combinations mean that there is a surface protection film for pretty much any application known to man. If you are not sure which type of protective film is right for your needs, we can ship you free samples of each type so you can test the different options.