bond becomes permanent. Effects of shape The adhesive bonding of a tape or label can be affected by its shape. Tapes with pointed corners start to detach at those corners; adhesive strength can be improved by rounding the corners. Applications Pressure-sensitive adhesives are designed for either permanent or removable applications. Examples of permanent applications include safety labels for power equipment, foil tape for HVAC duct work, automotive interior trim assembly, and sound/vibration damping films. Some high performance permanent PSAs exhibit high adhesion values and can support kilograms of weight per square centimeter of contact area, even at elevated temperature. These build adhesion to a permanent bond after several hours or days. Removal Removable adhesives are designed to form a temporary bond, and ideally can be removed after months or years without leaving residue on the adherend. Removable adhesives are used in applications such as surface protection films, masking tapes, bookmark and note papers, price marking labels, promotional graphics materials, and for skin contact (wound care dressings, EKG electrodes, athletic tape, transdermal drug patches, etc.). Some removable adhesives are designed to repeatedly stick and unstick. They have low adhesion and generally cannot support much weight. Sometimes clean removal of pressure sensitive tape can be difficult without damaging the substrate that it is adhered to. Pulling at a slow rate and with a low angle of peel helps reduce surface damage. PSA residue can be softened with certain organic solvents or heat. Extreme cold (dry ice, freeze spray, etc.) can cause viscoelastic materials to change to a glass phase; thus it is useful for removing many types of PSAs. Manufacture Pressure-sensitive adhesives are manufactured with either a liquid carrier or in 100% solid form. Articles such as tapes and labels are made from liquid PSAs by coating the adhesive on a support and evaporating the organic solvent or water carrier, usually in a hot air dryer. The dry adhesive may be further heated to initiate a cross-linking reaction and increase molecular weight. 100% solid PSAs may be low viscosity polymers that are coated and then reacted with radiation to increase molecular weight and form the adhesive (radiation cured PSA); or they may be high-viscosity materials that are heated to reduce viscosity enough to allow coating, and then cooled to their final form (hot melt PSA, HMPSA). Composition PSAs are usually based on an elastomer compounded with a suitable tackifier (e.g., a rosin