This method describes procedures for evaluating the following properties of envelopes : (1) film thickness of seal, (2) seal, seam, and window patch adhesion, (3) humidity resistance, (4) discoloration and staining of seal, seams, and patch.
The functionality of an envelope may be impaired if the adhesion characteristic between paper surfaces is impaired due to the changing environment to which the envelope is subjected.
These test procedures are useful for the comparison of envelope quality.
The precision statement in TAPPI T 411 is applicable for dry adhesive film thickness.
