Multilayer Clear Over Color Polyolefin Sheets and Layered Backing Structure
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 . A multilayer structure comprising:
a first thermoplastic layer having a polymeric component consisting essentially of virgin polyolefin;
a second thermoplastic layer including regrind polyolefin; and
a third thermoplastic layer having a polymeric component consisting essentially of virgin polyolefin;
the second thermoplastic layer being adjacent to the first thermoplastic layer and the third thermoplastic layer.
2 . The multilayer structure of claim 1 wherein the multilayer structure includes a clear polymer layer.
3 . The multilayer structure of claim 1 wherein the polymeric component of the second layer consists essentially of regrind.
4 . The multilayer structure of claim 3 wherein the bag strength of the first, second, and third layer is at least 5% greater than a control sample that is identical to the first, second, and third layer in formulation and dimension, but has a mono-layer structure that incorporates a blend of the regrind and the virgin polymer instead of a multi-layered structure.
5 . The multilayer structure of claim 2 wherein the multilayer structure further comprises a colored polymeric layer adjacent to the clear layer.
6 . The multilayer structure of claim 1 wherein the virgin polyolefin comprises a propylene homopolymer or a copolymer including polypropylene, and further comprises a very low density polyethylene.
7 . A backing layer for a multilayered polymeric structure comprising:
a first thermoplastic layer including a polymeric component, wherein the polymeric component consists essentially of a virgin polyolefin;
a second thermoplastic layer including regrind polyolefin;
a third thermoplastic layer having a polymeric component, wherein the polymeric component consists essentially of a virgin polyolefin;
the second thermoplastic layer being adjacent to the first thermoplastic layer and the third thermoplastic layer, if present.
8 . The backing layer of claim 7 wherein the polymeric component of the second layer consists essentially of regrind.
9 . The backing layer of claim 7 wherein the bag strength of the backing layer is at least 3% higher in terms of the time to bag, than a control sample that is identical to the backing layer in formulation and dimension, but has a mono-layer structure that incorporates a blend of the regrind and the virgin polymer instead of a multi-layered structure.
10 . The backing layer of claim 7 wherein the virgin polyolefin comprises a propylene homopolymer or a copolymer including polypropylene, and further comprises a very low density polyethylene.
11 . A method for forming a multilayered polymeric structure, the method comprising coextruding a first thermoplastic layer having a polymeric component that consists essentially of a virgin polyolefin, with a second thermoplastic layer including regrind polyolefin, and a third thermoplastic layer having a polymeric component that consists essentially of a virgin polyolefin;
the second thermoplastic layer being adjacent to the first thermoplastic layer and the third thermoplastic layer.
12 . The method of claim 11 wherein the coextrusion step further comprises coextruding a clear polymeric layer with the first, second, and third thermoplastic layers.
13 . The method of claim 11 wherein the coextrusion step further comprises coextruding a clear polymeric layer and a colored polymeric layer with the first, second, and third thermoplastic layers.
14 . The method of claim 11 further comprising thermoforming the coextruded multilayered polymeric structure to make a formed product.
15 . The method of claim 11 wherein the polymeric component of the second layer consists essentially of regrind.
16 . The method of claim 11 wherein the virgin polyolefin comprises a propylene homopolymer or a copolymer including polypropylene, and further comprises a very low density polyethylene.
17 . The method claim of 11 wherein the formed product is a backing layer for a vehicle body panel.
18 . The method of claim 11 wherein the bag strength of the multilayered polymeric structure after coextrusion is at least 3% higher in terms of the time to bag, than a control sample that is identical to the backing layer in formulation and dimension but has a mono-layer structure that incorporates a blend of the regrind and the virgin polymer instead of a multi-layered structure.