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.

It is claimed: 
     
         1 . An extruded polymeric composition comprising:
 60 to 99% by weight of the composition of a clear isotactic polypropylene/ethylene copolymer, wherein the copolymer has 70% or greater isotacticity, 0.5-12% ethylene content, a crystallinity greater than 60%, and a Rockwell hardness of R80 or greater; and   a clarifier present in an amount up to 3% by weight of the composition;   wherein the composition is adapted to be extruded into a sheet that prior to addition of any of pigment or special effects material has a haze of 10% or less.   
     
     
         2 . The extruded polymeric composition of  claim 1 , wherein the composition is adapted to be extruded into a sheet that prior to addition of any of pigment or special effects material has a haze of 5% or less. 
     
     
         3 . The extruded polymeric composition of  claim 1 , wherein the composition is adapted to be melt phase thermoformed into a clear sheet and the thermoformed clear sheet has a haze of 10% or less. 
     
     
         4 . The extruded polymeric composition of  claim 1 , further comprising: polypropylene, polyethylene, ethylene acid copolymer, or wax. 
     
     
         5 . The extruded polymeric composition of  claim 1 , further comprising:
 up to 25% by weight of the polymeric composition of a component selected from the group consisting of polypropylene, polyethylene, ethylene acid copolymer, or wax;   wherein the polypropylene, polyethylene, ethylene acid copolymer, or wax is a color carrier and the polyethylene is a linear low density polyethylene; and   up to 10% pigment, special effects additives, or pigment and special effects additives by weight of the composition.   
     
     
         6 . The extruded polymeric composition of  claim 1 , further comprising:
 a UV stabilizer, wherein the UV stabilizer is present in an amount of up to 10% by weight of the composition;   a slip agent, wherein the slip agent is present in an amount of up to 10% by weight of the composition;   an antioxidant, wherein the antioxidant is present in an amount of up to 1% by weight of the composition; and   optionally, a second antioxidant; wherein the antioxidant is present in an amount of up to 1% by weight of the composition.   
     
     
         7 . The extruded polymeric composition of  claim 1 , wherein the extruded polymeric composition is pelletized. 
     
     
         8 . The extruded polymeric composition of  claim 1 , further comprising a stress whitening agent or a low temperature impact modifier. 
     
     
         9 . The extruded polymeric composition of  claim 1 , wherein the clarifier comprises a sorbitol-based clarifier. 
     
     
         10 . The extruded polymeric composition of  claim 9 , wherein the sorbitol-based clarifier is a bis-propyl sorbitol. 
     
     
         11 . A clear, colored, or translucent extruded polymeric sheet layer comprising:
 an isotactic polypropylene/ethylene copolymer, wherein the copolymer has 70% or greater isotacticity, 0.5-12% ethylene content, a crystallinity greater than 60%, a Rockwell hardness of R80 or greater;   wherein the polymeric sheet layer has a Class A finish.   
     
     
         12 . The extruded polymeric sheet layer of  claim 11 , further comprising a clarifier present in an amount up to 3% by weight of the polymeric sheet layer and the isotactic polypropylene/ethylene copolymer is present in an amount of 50 to 99% by weight of the polymeric sheet layer. 
     
     
         13 . The extruded polymeric sheet layer of  claim 11 , further comprising: polypropylene, polyethylene, ethylene acid copolymer, or wax. 
     
     
         14 . The extruded polymeric sheet layer of  claim 12 , further comprising:
 up to 10% by weight of the polymeric sheet of pigment, special effects, or both; and   up to 25% by weight of the polymeric sheet layer of the polypropylene, polyethylene, ethylene acid copolymer, or wax, wherein the polypropylene, polyethylene, ethylene acid copolymer, or wax is a color carrier and the polyethylene is a linear low density polyethylene.   
     
     
         15 . The extruded polymeric sheet layer of  claim 12 , further comprising:
 a UV stabilizer, wherein the UV stabilizer is present in an amount of up to 10% by weight of the polymeric sheet;   a slip agent, wherein the slip agent is present in an amount of up to 10% by weight of the polymeric sheet;   an antioxidant, wherein the antioxidant is present in an amount of up to 1% by weight of the polymeric sheet; and   optionally, a second antioxidant; wherein the antioxidant is present in an amount of up to 1% by weight of the polymeric sheet.   
     
     
         16 . The extruded polymeric sheet layer of  claim 11 , wherein the sheet layer is colored, the isotactic polypropylene/ethylene copolymer is present in an amount of 60 to 95% by weight of the polymeric sheet layer, and the polymeric sheet layer further comprises up to 20% by weight of the composition pigment, special effects material, or both and up to 25% of a color carrier comprising an LLDPE, ethylene acid copolymer, wax, or polypropylene. 
     
     
         17 . The extruded polymeric sheet of  claim 1 , wherein the polymeric sheet is exclusive of filler. 
     
     
         18 . A method for making a polymeric sheet, the method comprising:
 making an additive concentrate by steps including:
 feeding a UV stabilizer, slip agent, or both together with a carrier resin to a first extruder; and 
 extruding the additive concentrate; 
   and making a polymeric sheet layer by steps including:
 feeding a polyolefin and the additive concentrate to a second extruder; and 
 extruding the polymeric sheet layer; 
   wherein the polymeric sheet layer comprises a layer including 60 to 99% by weight of the sheet layer of a clear isotactic polypropylene/ethylene copolymer, wherein the copolymer has 70% or greater isotacticity, 0.5-12% ethylene content, a crystallinity greater than 60%, and a Rockwell hardness of R80 or greater; and   a clarifier present in an amount up to 3% by weight of the sheet layer;   wherein the composition is adapted to be extruded to create a sheet layer that prior to addition any of pigment or special effects material has a haze of 10% or less.   
     
     
         19 . The method of  claim 18 , further comprising, feeding a clarifier, an antioxidant, or both to the second extruder. 
     
     
         20 . The method of  claim 18 , wherein the polymeric sheet layer comprises a stress whitening agent or a low temperature impact modifier. 
     
     
         21 . The method of  claim 18  further comprising sheet coextruding the polymeric sheet layer with a backing layer sheet, wherein the backing layer sheet comprises pigment, to form a multilayer stack exclusive of a tie layer. 
     
     
         22 . The method of  claim 21 , wherein the backing layer sheet is made and coextruded by the steps including:
 adding a polyolefin and talc filler to a continuous mixer and 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, adding the thermoplastic polyolefin pellets to the backing layer sheet extruder, and coextruding the backing layer sheet with the polymeric sheet to form the multilayer stack.   
     
     
         23 . The method of  claim 18 , further comprising forming the polymeric sheet by heat, stretching, or both heat and stretching. 
     
     
         24 . The method of  claim 22 , further comprising forming the polymeric sheet by heat, stretching, or both heat and stretching, and the polymeric sheet 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 and has a DOI of 70 or greater. 
     
     
         25 . A multilayer polymeric structure comprising:
 a clear, colored, or translucent top polymeric layer that includes an isotactic polypropylene/ethylene copolymer, wherein the copolymer has 70% or greater isotacticity, 0.5-12% ethylene content, a crystallinity greater than 60%, a Rockwell hardness of R80 or greater; and   a polyolefinic backing layer;   wherein the multilayer polymeric structure is sheet coextruded and is exclusive of a tie layer;   wherein the 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.   
     
     
         26 . The multilayer polymeric structure of  claim 25 , wherein the top polymeric layer further comprises a clarifier that is present in an amount up to 3% by weight of the top polymeric layer and the isotactic polypropylene/ethylene copolymer is present in an amount of 50 to 99% by weight of the top polymeric layer. 
     
     
         27 . The multilayer polymeric structure of  claim 26 , wherein the top polymeric layer further comprises:
 up to 10% by weight of the top polymeric layer of pigment &/or special effects; and   up to 25% by weight of the polymeric sheet of the polypropylene, polyethylene, ethylene acid copolymer, or wax, wherein the polypropylene, polyethylene, ethylene acid copolymer, or wax is a color carrier and the polyethylene is a linear low density polyethylene.   
     
     
         28 . The multilayer polymeric structure of  claim 27 , wherein the top polymeric layer further comprises:
 a UV stabilizer, wherein the UV stabilizer is present in an amount of up to 10% by weight of the top polymeric layer;   a slip agent, wherein the slip agent is present in an amount of up to 10% by weight of the top polymeric layer;   an antioxidant, wherein the antioxidant is present in an amount of up to 1% by weight of the top polymeric layer;   optionally, a second antioxidant; wherein the antioxidant is present in an amount of up to 1% by weight of the top polymeric layer.   
     
     
         29 . The multilayer polymeric structure of  claim 28 , wherein the polymeric structure has a Class A finish. 
     
     
         30 . The method of  claim 18 , wherein the polymeric sheet is not treated to induce cross-linking. 
     
     
         31 . The multilayer polymeric structure of  claim 28 , wherein the polymeric structure further comprises a stress whitening agent or a low temperature impact modifier.