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US 2007/0184259 A1Published application
Multilayer polymer sheets
AssigneeDow Global Technologies LLC
InventorsKurt Brunner, Henri Mispreuve
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Abstract
The present invention relates to multilayer sheets which are suitable for packaging applications, methods of producing multilayer sheets and articles manufactured from producing multilayer sheets.
Claims10
A multilayer sheet comprising at least one foamed propylene polymer layer and at least one non-foamed polymer layer, wherein the non-foamed polymer layer comprises a polymer comprising units derived from an 1 -alkene monomer, characterized in that multilayer sheet has properties which satisfy the following relationships:
- 0.2<T<2 (1a)
- wherein T is the total thickness of the multilayer sheet measured according to ASTM D645-97 expressed in millimetres;
- and
- 100<G<500 (1b)
- wherein G is the grammage of the multilayer sheet determined according to ASTM D646-96 expressed in grams per square metre;
- and
- S≧2×10−7G3.1872 (1c)
- wherein S is the geometric mean bending moment of the multilayer sheet expressed in milliNewton metres calculated from the following relationship:
- S=(Sm Sc)0.5 (1d)
- wherein Sm is the maximum bending moment in the plane of the multilayer sheet expressed in milliNewton metres and determined according to the two-point method described in DIN 53121:1996-12 and Sc is the bending moment measured perpendicularly to the direction of Sm in the plane of the multilayer sheet expressed in milliNewton metres and determined according to the two-point method described in DIN53121:1996-12.
7 more elements
Dependencies are inferred from the claim text.