Cross directional zoned bicomponent films, film laminates, and systems and methods for manufacture of the same
View Patent ↗Coextruded films provide cross directional zoned multiple components side-by-side to one another. Systems and methods relate to coextruding such films. During coextrusion, a first polymer conjoins with a second polymer while a temperature differential is maintained between the first and second polymers. This temperature differential is selected to reduce a difference between the viscosities of the first and second polymers making the viscosity of the first polymer close enough to the viscosity of the second polymer to avoid separation upon coextrusion. Further, the films may form a layer in subsequent lamination to other material layers.
1. An edge laminated film, comprising:
a first polymer shaped in a planar form that is continuously extended by a second polymer laminated along an edge of the first polymer as defined by a thickness of the planar form,
wherein the first polymer has a viscosity versus temperature curve, as measured at shear rates of 500 1/s, 1000 1/s or 1500 1/s, at least 10 percent different in viscosity than the second polymer at every common temperature throughout a melt temperature range of each as calculated relative to the higher viscosity value of each of the polymers, the viscosity determined by a capillary rheometer equipped with a 1 mm die utilizing a 10:1 length to diameter ratio and a 60° entrance angle, and
wherein the melt temperature range for a respective one of the polymers is defined as a temperature at a softening peak of a differential scanning calorimetry (DSC) curve to a maximum of 25° C. less than a degradation peak of the DSC curve, as determined by the DSC curve obtained for a 5.5 mg sample of the respective one of the polymers heated at 20° C./minute, wherein the first polymer includes polyethylene and poly(styrene/ethylene-butylene/styrene) and the second polymer includes polypropylene, polyethylene, and ploy(styrene/ethylene-butylene/styrene).
2. The edge laminated film of claim 1 , wherein the first polymer is relatively more elastic than the second polymer.
3. The edge laminated film of claim 1 , wherein the first polymer is elastomeric and the second polymer is non-elastomeric.
4. The edge laminated film of claim 1 , wherein the first and second polymers are disposed between first and second additional material layers laminated to respectively first and second faces of the planar form.
5. The edge laminated film of claim 4 , wherein the first and second additional material layers are each nonwoven fibrous layers.
6. The edge laminated film of claim 4 , wherein the first and second additional material layers are each spunbonded polypropylene materials.
7. The edge laminated film of claim 1 , wherein the second polymer is directly laminated without intervening adhesive along the edge of the first polymer.