Patent ID: 9744706
Date: 2017-08-29
CPC Classifications: B29C,B29K,B29L,B32B,B65D

Claim:
1. A method of forming a multi-layered thermoplastic bag with tailored bond strength of the melt bond between the layers of the bag, the method comprising: extruding a first thermoplastic layer of film; extruding a second thermoplastic layer of film, the second thermoplastic layer of film being incompatible with the first thermoplastic layer of film; joining the first thermoplastic layer of film directly to the second thermoplastic layer of film before a frost line area while each of the first and second thermoplastic layers of film remain in a melt state from the extruding; solidifying the joined first thermoplastic layer of film and second thermoplastic layer of film at the frost line area to form a melt-bonded film with a melt bond strength between the first thermoplastic layer of film and the second thermoplastic layer of film that is less than a weakest tear strength of the first thermoplastic layer of film and the second thermoplastic layer of film whereby forces acting on the melt-bonded film are first absorbed by breaking the melt bond between layers rather than, or prior to, tearing or otherwise causing failure of either one of the first and second layers of the melt-bonded film; regulating temperature during the solidifying to establish the frost line area; and forming the melt-bonded film into a thermoplastic bag.