Multilayered clear over color polyolefin sheets and layered backing structure

Abstract

A multilayer structure includes a clear polyolefin layer, a colored polyolefin layer, and a random polyolefin backing layer. The colored and backing layers are coextruded and are permanently bonded at a layer interface, which is exclusive of an adhesive. The structure has a DOI of 70 or greater and passes a gravelometer impact test per the GM9508P standard, with a 10 pint load, at a −30° C. temperature, and at an impact angle of 30 degrees. Among other uses, the structures are appropriate for use as body panels in the motor vehicle industry. The structures display a “class A” finish and meet a variety of requirements for durability and weatherability. An ABA structured backing layer and a method of making it are also described herein.

1 . (canceled) 
     
     
         2 . A multilayer polymeric sheet comprising:
 a top polymeric layer that includes 70 to 99.1% by weight of a first polypropylene/ethylene copolymer that is isotactic and has a 0.5% to 12% by mole ethylene content; and   a backing layer on the opposite side of the sheet from the top polymeric layer, the backing layer comprising a thermoplastic polyolefin and a filler;   wherein the multilayer polymeric sheet is sheet coextruded and is exclusive of an adhesive layer;   the top polymeric layer further comprising at least one of: a slip agent, a nucleating agent, a clarifying agent, or combinations of these;   wherein the multilayer polymeric sheet has a DOI of 70 or greater and passes a gravelometer impact test per the GM9508P standard, with a 10 pt load, at a −30° C. temperature, and at an angle of 30 degrees, with a rating of 7 or greater and no delamination or cracking.   
     
     
         3 . The multilayer polymeric sheet of  claim 2 , wherein the top polymeric layer is clear and further comprising a colored or translucent polymeric layer between the top polymeric layer and the backing layer, which includes 60 to 99% by weight of a second polypropylene/ethylene copolymer having a 0.5 to 12% ethylene content, wherein the first and second polypropylene/ethylene copolymer are the same or different. 
     
     
         4 . The multilayer polymeric sheet of  claim 2 , wherein the top polymeric layer further comprises the clarifying agent in an amount of 0.0001 to 3% by weight of the top polymeric layer, or the nucleating agent in an amount of 0.0001 to by weight of the top polymeric layer, or both. 
     
     
         5 . The multilayer polymeric sheet of  claim 4 , wherein the top polymeric layer includes:
 a UV stabilizer in an amount of 0.0001 to 10% by weight of the top polymeric layer;   a slip agent, in an amount of 0.0001 to 10% by weight of the top polymeric layer;   an antioxidant in an amount of 0.0001 to 2% by weight of the top polymeric layer.   
     
     
         6 . The multilayer polymeric sheet of  claim 2 , wherein the multilayer polymeric sheet has a gloss of 75 or greater at a 60° angle and a gloss of 60 or greater at a 20° angle. 
     
     
         7 . The multilayer polymeric sheet of  claim 2 , wherein the backing layer is 3 to 500 mils in thickness and the top polymeric layer 1 to 20 mils in thickness. 
     
     
         8 . The multilayer polymeric sheet of  claim 7 , wherein the backing layer further comprises a polyethylene or an ethylene copolymer rubber and the filler comprises talc. 
     
     
         9 . The multilayer polymeric sheet of  claim 2 , wherein the multilayer polymeric sheet has a Class A finish. 
     
     
         10 . The multilayer polymeric sheet of  claim 2 , wherein the top polymeric layer is exclusive of a metallocene-based homopolymer or copolymer of polypropylene and the multilayer polymeric sheet is not treated to induce cross-linking. 
     
     
         11 . The multilayer polymeric sheet of  claim 4 , wherein the clarifier comprises a polyol-based clarifier. 
     
     
         12 . The thermoformed product of  claim 11 , wherein the thermoformed product has no more than three layers, wherein the first polymeric layer is on a top surface, and the second polymeric layer is on a bottom surface of the thermoformed product. 
     
     
         13 . The multilayer polymeric sheet of  claim 5 , wherein the top polymeric layer comprises a stress whitening agent. 
     
     
         14 . A thermoformed product comprising:
 a coextruded sheet comprising a first polymeric layer that includes 60 to 99% by weight of a first polypropylene/ethylene copolymer that is isotactic and has a 0.5 to 12% by mole ethylene content and further comprising at least one of a nucleating agent, a clarifying agent and a slip agent; and a second polymeric layer comprising a thermoplastic polyolefin and a filler; the coextruded sheet being exclusive of an adhesive layer; the coextruded sheet thermoformed to produce a multilayer product that has a DOI of 70 or greater and passes a gravelometer impact test per the GM9508P standard, with a 10 pt load, at a −30° C. temperature, and at an angle of 30 degrees, with a rating of 7 or greater and no delamination or cracking.   
     
     
         15 . The thermoformed product of  claim 14 , wherein the first polymeric layer is clear and further comprising a colored or translucent polymeric layer between the first polymeric layer and the second polymeric layer, wherein the second polymeric layer includes 60 to 99% by weight of a second polypropylene/ethylene copolymer having a 0.5 to 12% ethylene content by mole, wherein the first and second polypropylene/ethylene copolymer are the same or different. 
     
     
         16 . The thermoformed product of  claim 14 , wherein the first polymeric layer further comprises the clarifying agent in an amount of 0.0001 to 3% by weight of the first polymeric layer, or the nucleating agent in an amount of 0.0001 to 5% by weight of the first polymeric layer, or both. 
     
     
         17 . The thermoformed product of  claim 16 , wherein the first polymeric layer further comprises:
 a UV stabilizer in an amount of 0.0001 to 10% by weight of the top polymeric layer;   a slip agent, in an amount of 0.0001 to 10% by weight of the top polymeric layer;   an antioxidant in an amount of 0.0001 to 2% by weight of the top polymeric layer.   
     
     
         18 . The thermoformed product of  claim 14 , wherein the first polymeric layer has a haze of 10 or less. 
     
     
         19 . The thermoformed product of  claim 14 , wherein the thermoplastic polyolefin of the second polymeric layer has a random microstructure. 
     
     
         20 . The thermoformed product of  claim 14 , wherein at least one of the first or second polymeric layer is not treated to induce cross-linking. 
     
     
         21 . The thermoformed product of  claim 14  having a gloss of 75 or greater at a 60° angle and a gloss of 60 or greater at a 20° angle. 
     
     
         22 . The thermoformed product of  claim 14 , wherein the backing layer is 3 to 500 mils in thickness and the top polymeric layer is 1 to 20 mils in thickness. 
     
     
         23 . A multilayer polymeric structure comprising:
 a clear, colored, or translucent top polymeric layer that includes 70 to 99.1% by weight of an isotactic polypropylene/ethylene copolymer that has a 0.5 to 12% by mole ethylene content;   a backing layer on the opposite side of the structure from the top polymeric layer, the backing layer comprising a thermoplastic polyolefin and a filler;   an optional colored or translucent layer between the top polymeric layer and the backing layer, the optional colored or translucent layer having 60 to 99% by weight of an isotactic polypropylene/ethylene copolymer and has a 0.5 to 12% by mole ethylene content;   wherein the multilayer polymeric structure is sheet coextruded and is exclusive of an adhesive layer;   the top polymeric layer further comprising at least one of: antioxidants, UV stabilizers, slip agents, or combinations of these;   wherein at least one of the backing layer or the top polymeric layer is not treated to induce cross-linking;   wherein the multilayer polymeric structure passes a gravelometer impact test per the GM9508P standard, with a 10 pt load, at a −30° C. temperature, and at an angle of 30 degrees, with a rating of 7 or greater and no delamination or cracking.   
     
     
         24 . The multilayer polymeric structure of  claim 23 , wherein the multilayer polymeric structure is melt-phase thermoformed. 
     
     
         25 . A method of making a multilayer polymeric structure comprising the steps of:
 coextruding a clear, colored, or translucent top polymeric layer that includes 70 to 99.1% by weight of an isotactic polypropylenelethylene copolymer that has a 0.5 to 12% by mole ethylene content with a backing layer on the opposite side of the structure from the top polymeric layer, the backing layer comprising a thermoplastic polyolefin and a filler; and optionally coextruding the top polymeric layer and backing layer with an optional colored or translucent layer between the top polymeric layer and the backing layer, the optional colored or translucent layer having 60 to 99% by weight of an isotactic polypropylene/ethylene copolymer and a 0.5 to 12% by mole ethylene content;   wherein the multilayer polymeric structure is exclusive of an adhesive layer;   the top polymeric layer further comprising at least one of antioxidants, UV stabilizers, slip agents, or combinations of these;   wherein at least one of the backing layer or the top polymeric layer is not treated to induce cross-linking;   wherein the multilayer polymeric structure passes a gravelometer impact test per the GM9508P standard, with a 10 pt load, at a −30° C. temperature, and at an angle of 30 degrees, with a rating of 7 or greater and no delamination or cracking.   
     
     
         26 . The method of  claim 25 , further comprising thermoforming the multilayer polymeric structure;
 wherein after thermoforming the multilayer polymeric structure is a formed product that passes a gravelometer impact test per the GM9508P standard, with a 10 pt load, at a −30° C. temperature, and at an angle of 30 degrees, with a rating of 7 or greater and no delamination or cracking.   
     
     
         27 . The method of  claim 26 , wherein the multilayer structure is not injection molded, injection backfilled, or simultaneous in-mold thermoforming/injection backfilled. 
     
     
         28 . The method of  claim 26 , wherein the multilayer structure has a thickness of 150 mils to 560 mils. 
     
     
         29 . The method of  claim 25  wherein the backing layer comprises pigment, wherein the backing layer sheet is made and coextruded by steps including:
 adding the thermoplastic polyolefin and the filler to a mixer, melt blending, and then pelletizing a product of the mixer to form thermoplastic polyolefin pellets; 
 adding color concentrate pellets that include the pigment to a backing layer sheet extruder and adding the thermoplastic polyolefin pellets to the backing layer sheet extruder; 
 then performing the coextruding step. 
 
     
     
         30 . The multilayer polymeric sheet of  claim 26 , wherein the polyol-based clarifier is 1,2,3-trideoxy-4,6:5,7-bis-O-[(4-propylphenyl)methylene]-nonitol. 
     
     
         31 . The method of  claim 25 , further comprising thermoforming the multilayer polymeric structure directly from a coextruded sheet formed from the coextniding step.