When adhesive first makes contact with a surface the level of bound or stickiness is called “tack”. As time passes or pressure is exerted the adhesive flows onto, and makes complete surface contact on the sign substrate it achieves “ultimate adhesion”. The difference between tack and ultimate adhesion is substantial. In fact ultimate adhesion can be over 400% greater than tack when film is applied with the standard method (squeegee + elbow grease). Knowing how to adjust the level of tack and understanding the rate at which bond levels rise will make applications much easier and allow bubble and trouble-free sign installations.
Bond increase is due to increased surface contact attained through the flow of the adhesive layer. At the time of application, “tack” is about 2.2 lb. per inch width (1 kg/2.5 cm). The bond may build to more than double after 1 day. In 7 days, ultimate adhesion may reach over 9 lbs per inch.
If film needs to be deformed (stretched) to achieve contact, using heat while installing will significantly increase initial contact and reduce problems during the service life.
Special films have been developed to have lower tack or slower adhesion build due to the application requirements for specific signage. Translucent Series 2500 has a slow build adhesive which allows thermoformers the opportunity of removing areas of film from the sign face for several days after application and forming.
Many of these TIPS come from our customer feedback and questions so be sure to reach out to us so that we can help you and in turn help others as well! Arlon Technical Services is here for you.