Alloy comprising polyolefin and thermoplastic polyurethane

Abstract

This invention relates to an alloy comprising polyurethane and polyolefin. It has now surprisingly been found that a specific composition of polyolefin and polyurethane has surprising mechanical properties and at the same time has transparent characteristics and/or appearance. The present invention provides an alloy with remarkable mechanical properties. The phases do not macro-phase separate. Thus, this stable and potentially broad interface is very effective in stress transfer when the alloy is strained. As one might expect, the hardness values for the alloys are in between the hardness values of each component but the other physical properties are no so adjusted. In this way, when considering the hardness and mechanical values, these alloys behave like two compatible polymers.

1 . A composition comprising (i) a thermoplastic polyurethane (TPU), (ii) a polyolefin (PO), and (iii) a compatibilizing amount of an alloy of a thermoplastic polyurethane (TPU) and a Polyolefin (PO), the alloy having at least one of the following properties:
 a ratio between surface tension of the TPU and surface tension of the PO measured above a melt temperature of the alloy is between 0.5 to 1.5;   the PO contains at least one functional group that can form long range interactions with one or more segments of the TPU; and   a viscosity of a discrete phase over a viscosity of a matrix phase is below 2 under processing conditions.   
     
     
         2 . A composition according to  claim 1 , wherein the PO is selected from the group consisting of polyethylene (PE), polypropylene (PP), copolymer of polyethylene, and copolymer of polypropylene. 
     
     
         3 . A composition according to  claim 1 , wherein the PO is formed from copolymers of monoolefins and diolefins with each other or with vinyl monomers. 
     
     
         4 . A composition according to  claim 1 , wherein the PO is a polyethylene. 
     
     
         5 . A composition according to  claim 1 , wherein the PO is a Polypropylene. 
     
     
         6 . A composition according to  claim 1 , wherein the ratio between the surface tension of the TPU and the surface tension of the PO above the melt temperature of the alloy is between 0.8 and 1.2. 
     
     
         7 . A composition according to  claim 1 , wherein Mn for a polyTHF segment of the TPU is greater than 1000 g/mol. 
     
     
         8 . A composition according to  claim 1 , wherein the least one functional group that can form a long range interaction with one or more segments of the TPU is a group that can form a hydrogen bonding with the one or more segments of the TPU. 
     
     
         9 . A composition according to  claim 1 , wherein the viscosity of the discrete phase over the viscosity of the matrix phase is between 10 and 0.1. 
     
     
         10 . A composition according to  claim 1 , wherein the discrete phase is the PO phase, and the matrix phase is the TPU phase. 
     
     
         11 . A composition according to  claim 1 , wherein a ratio between a refractive index of the TPU and a refractive index of the PO at room temperature is between 0.8 and 1.2. 
     
     
         12 . A composition according to  claim 1 , wherein the TPU has a haze below 30 and the PO has a haze below 30. 
     
     
         13 . A composition according to  claim 1 , wherein the alloy further comprises a plasticizer. 
     
     
         14 . A composition according to  claim 1 , wherein the alloy consists essentially of TPU and PO. 
     
     
         15 . A composition according to  claim 1 , wherein the alloy comprises 30-70 (w/w) % TPU. 
     
     
         16 . A composition according to  claim 1 , wherein the alloy comprises 30-70 (w/w) % polyolefin.