1-4 PRINCIPLES OF OPERATION
The laminator operates by pulling film with a thermally activated adhesive over a heated set of
laminating rollers. Film from a supply roll passes over heat rollers to activate a polyethylene adhesive
layer on the film. Then, as it passes through the heated rubber rollers they apply pressure and bond the
film to the item being laminated. The film's adhesive is pressed into the ink and fibers on the surface
of the paper.
The strength of the lamination bond can be checked by cutting a large “X” on the surface of a
laminated sample with a sharp blade. Use the tip of the blade to pry up one corner of the “X”. Grab
that corner and pull up the film. Ink and/or paper fibers coming up with the layer of film indicates a
good adhesive bond.
If the film comes up too easily, with no ink or paper, the lamination was probably done at too low a
temperature. Check the instructions that may have come with your laminating film and/or the
lamination temperature chart in section 5-5.
Please note that when doing an X-test on glossy (coated) paper, a good X-test will pull up ink only.
The film should not come up easily. When laminating material that is not glossy (uncoated), the paper
is often more fibrous and a good X-test will yield ink and paper fibers coming up with the film.
1-5 LAMINATING
FILM
Most thermal laminating film consists of two layers: a base of polyester and an adhesive layer of
polyethylene. The polyester layer forms the harder outer surface of the film and does not melt at
laminating temperature. It provides rigidity and protection for your laminated items. The greater the
polyester content, the higher the level of protection, rigidity and luster. The polyethylene layer melts
at laminating temperature and bonds the film onto the subject material under the pressure of the
laminating rollers. As an X-test demonstrates, the adhesive is pressed into the paper and fills
irregularities in the surface.
The proportion of polyester and polyethylene in a film is usually described with numbers. For
example, a “1-2” film consists of one mil of polyester and two mils of polyethylene. The first number
refers to the base layer. The second number refers to the adhesive layer. A mil is 1/1000 of an inch.
Since polyester is the more costly of the two types of plastic generally used in laminating film, a “3-2”
film will cost more than a “2-3” film. Both are 5-mil films but the “3-2” version will seem a little
thicker on a piece of laminated material because it will be slightly stiffer. Thermal laminating films
are available in many different base/adhesive combinations. Five-mil film, for example, can be found
in 1-4, 2-3, 3-2 and 4-1 combinations.
In the US laminating trade, the generally accepted practice is to describe two-sided lamination, or
encapsulation, by the thickness of one layer of film. For example, “3-mil lamination” should refer to
lamination with two layers of 3-mil film. If you are buying or selling laminating film or lamination
services, please make sure both parties understand the film descriptions being used.
There is a huge variety of thermal laminating films available to suit many different kinds of
application. Here are some of the more commonly used “special” film types or film additives:
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