Sealing of Tyvek with HDPE film, and HDPE with HDPE (easy-tear band) is best performed using a validated impulse sealing device, not constant heat.
Pall Life Sciences does not sell sealing devices but has good experience with the following companies:
Processing Parameters of Impulse Sealer
Best sealing results of High Density Poly-Ethylene (HDPE) are obtained under moderate temperature-time-pressure conditions:
Contact pressure is not adjustable in most cases, and is set by the manufacturer. Good maintenance and calibration of the sealing equipment is crucial and must be validated on a regular basis. If bad sealing results are obtained, do not change validated time and temperature conditions but check alignment of sealing bars and age of the sealing wire coverings (Teflon).