PTFE- tapes can be supplied in virtually any width, but standard sizes are more readily available. When determining width it is important to allow an adequate width of tape that is not adhesive coated in the zone that comes in contact with the heatseal band. Adhesive in contact with the heatseal band impedes free movement, as the band expands and contracts with temperature change. This can cause the heatseal band to buckle or distort or cause the tape to wrinkle. Either way, the quality of the heatseal is adversely affected. For these reasons, PTFE- tapes are offered in several styles.
For heat sealing applications, standard grade is commonly used; however, Premium grade is available in most configurations. Premium grade (Grade A) is made with a heavier coating of PTFE- which produces a smoother surface and better release characteristics at the expense of slightly slower heat transfer. A 5 mil, premium grade, self-adhesive PTFE- tape is a good selection for covering the elastomers on a heat seal jaw. Premium grade 3 mil, cover strip, is the best selection for covering heatseal bands.
PTFE- Cloth ( non-adhesive)
This material is most commonly used to cover special profile bands and platens or irregular shapes where a self adhesive (pressure sensitive) tape cannot be used because of adhesive contact with the heatseal band or other adhesive free surface.