This type of opening is obtained by applying elements such as Freon gas, dry ice, liquid nitrogen etc. The main objective is to freeze the adhesive, unfasten the tape and in such a manner allow the bag to be opened. Then at room temperature it is possible to seal it again without leaving evidence.
EVIDENCE: The tape will display a different appearance (light blue shades). In some parts of the tape the signs OPEN VOID will appear. By applying extremely cold temperatures (-40 ºC or below) the signs of OPEN VOID are immediately released.
UNDER DIRECT HEAT
This type of opening is obtained by applying high temperatures to the tape, making the adhesive change its properties abruptly. The most common opening methods are: a blow-dryer's hot air, water vapor or with the flame of a lighter. The purpose of heat is to unfasten the adhesive and detach the tape to open and close the bag again without leaving evidence.
EVIDENCE: The bag will display a sticky, creased appearance and the surface will be distorted and withered. When temperatures above 80º C are applied the signs of OPEN VOID along the bag are released.
The solvents determine how external elements act upon the tape, inhibiting the adhesive action (modifying its properties). The most common solvents are gasoline, alcohol and thinner among others. They act directly upon the adhesive inhibiting its adhesive strength, dissolving and detaching it