Each window film manufacturer has their own proprietary formula for developing adhesives. Despite these differences, there are basically two types of adhesives
Laminating and Mounting. Laminating adhesives are applied during the manufacturing process where two or more plies of raw materials are fused together. Mounting adhesives are used to adhere film to the glass.
There are predominantly two types of mounting adhesives used in the window film industry todayPressure Sensitive (PS) and Dry Adhesive (DA). Although each type of adhesive has its own particular attribute, the general application procedure remains the same for both.
The primary difference between the two mounting adhesives is the way they react to glass. A Pressure Sensitive adhesive forms an immediate mechanical bond to glass and becomes marginally stronger during the curing/drying process. The reaction is similar to every day adhesive tape. The adhesive is in a ready state of usage and simply requires slight pressure to bond with a surface. The squeegeeing process is not only designed to remove mounting solution, but the firm press against the glass initiates
the PS adhesion process as well.
The primary benefit of Pressure Sensitive adhesive is immediate adhesion, although the bond is not fully complete until the film is finally cured. PS films make the application process easier when working alone or in tight spaces. That’s why PS films are the preferred option for automotive applications. It’s important to note that Safety and Security films require a thicker PS adhesive because their heavier construction requires immediate adhesion. Otherwise, the film would peel away from the window due to its density. When glass breakage occurs, the thicker PS adhesive allows the glass to remain adhered to the film rather than fragmenting outward.
In contrast to PS adhesives, Dry Adhesives aren’t sticky to the touch when the liner is removed because the adhesive is not activated until it is exposed to moisture. Even after spraying mounting solution, the dry adhesive will not feel “tacky” like a Pressure Sensitive adhesive. This is due to the fact that dry adhesives are designed to form a chemical bond to the glass. Once activated by water, the sticky properties of a DA adhesive seek out the pores in the glass to complete the bonding process.
The advantage of DA adhesives is that it forms a stronger bond to the glass after curing. Additionally, DA adhesives will last longer and have a greater degree of optical clarity. Because the exposed DA adhesive is not tacky, it will also reduce the chance of contamination from airborne particles during the installation process.
While mounting adhesives allow the film to bond to the glass, a laminating adhesive is used during the manufacturing process to join two or more film pieces together in order to develop a final film product. For example, a laminating adhesive would be used to bond a clear polyester film layer to another metallized or dyed film layer to create a thicker solar control film product.
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