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US 2022/0290010 A1Published application
Multilayer films having foamed polyolefin based adhesive composition(s)
AssigneeEquistar Chemicals, LP
InventorsMICK C. HUNDLEY, GANG ZHANG, WILLIAM R. PODBORNY
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Abstract
A multilayer film having enhanced toughness and optical properties is provided. The multilayer film includes a base layer, an outer layer, and a tie layer between the base layer and the outer layer. The multilayer film can also include additional layers. Methods for making such multilayer films are also provided. Multilayer films according to the present invention are particularly useful packaging applications where rupture resistance and high clarity are desirable.
Claims20
A film comprising:
- a. a base layer;
- b. a first outer layer;
- and
- c. a first tie layer disposed between the first outer layer and the base layer, the first tie layer comprising a first foamed polyolefin-based adhesive composition.
1 more element
A method for forming a multilayer film comprising:
- a. adding a polyolefin-based adhesive composition and a gas to an extruder and mixing under pressure and temperature conditions sufficient to produce a mixture of melted polyolefin-based adhesive composition and dissolved gas;
- b. heating portions of each:
- i) a first polymer, and
- ii) a second polymer,
- c. co-extruding:
- i) a first layer comprising the first polymer,
- ii) a second layer comprising the second polymer, and
- iii) a tie layer disposed between the first layer and the second layer, the tie layer comprising a matrix of melted polyolefin-based adhesive composition with a dispersed phase of gas cells formed when the tie layer exits the extruder, to form a multilayer melt;
- and
- d. decreasing the temperature of the multilayer melt at a controlled rate to induce collapse of at least a portion of the gas cells prior to solidification of the polyolefin-based adhesive composition.
7 more elements
A method for forming a multilayer film comprising:
- a. providing an extrusion apparatus having at least one extruder, the extruder having a die through which polymer in the extruder is discharged during extrusion, wherein components of the apparatus are arranged such that during extrusion of a matrix of melted polyolefin-based adhesive comprising a dispersed phase of gas cells, cooling of the melted polyolefin-based adhesive after discharge from the die is limited to a rate sufficient to induce collapse of at least a portion of the gas cells prior to crystallization of the polyolefin-based adhesive;
- b. adding a polyolefin-based adhesive composition and a gas to an extruder and mixing under pressure and temperature conditions sufficient to produce a mixture of melted polyolefin-based adhesive composition and dissolved gas;
- c. discharging the mixture from a die attached to the extruder to reduce the pressure of the mixture an amount sufficient produce a layer comprising a matrix of melted polyolefin-based adhesive composition comprising a dispersed phase of gas cells;
- d. forming a multilayer structure comprising:
- i) a first layer;
- ii) a second layer;
- and
- iii) the layer comprising a matrix of melted polyolefin-based adhesive composition comprising a dispersed phase of gas cells, disposed between and coextensively adhered to the first layer and the second layer;
- and
- e. decreasing the temperature of the matrix of melted polyolefin-based adhesive composition comprising gas cells at a controlled rate to induce collapse of at least a portion of the gas cells prior to solidification of the polyolefin-based adhesive composition.
7 more elements
Dependencies are inferred from the claim text.