High Gloss Thermoformed Article and Process for Producing Same
The present disclosure is directed to a thermoforming process and thermoformed articles produced therefrom. The thermoforming process includes heating a structure with a gloss layer composed of a propylene-based polymer having a melt flow rate from about 0.1 g/10 min to about 1.5 g/10 min, and producing a thermoformed article wherein the gloss layer has a post-thermoformed Gardner gloss value within 25% of the pre-thermoformed Gardner gloss value for the gloss layer. The thermoformed article may have a gloss layer with a post-thermoformed Gardner gloss value greater than or equal to about 60.
1 . A process comprising:
heating a structure to a surface temperature from about 190° C. to less than 230° C., the structure comprising a gloss layer comprising a propylene-based polymer with a melt flow rate from about 0.1 g/10 min to about 1.5 g/10 min as measured in accordance with ASTM D-1238; and
thermoforming the structure into a thermoformed article, the gloss layer having a post-thermoformed Gardner gloss value within about 25% of the gloss layer pre-thermoformed Gardner gloss value as measured in accordance with ASTM D-523 at 60°.
2 . The process of claim 1 comprising producing a gloss layer having a post-thermoformed Gardner gloss value greater than or equal to about 60.
3 . The process of claim 1 wherein the propylene-based polymer comprises greater than about 3.5 wt % units derived from ethylene, the process comprising heating the structure to a surface temperature from about 204° C. to about 215° C. and producing a gloss layer with a post-thermoformed Gardner gloss value greater than or equal to about 80.
4 . The process of claim 1 wherein the propylene-based polymer comprises less than about 3.5 wt % units derived from ethylene, the process comprising heating the structure to a surface temperature from about 190° C. to about 210° C. and producing a gloss layer with a post-thermoformed Gardner gloss value greater than or equal to about 60.
5 . The process of claim 1 comprising coextruding to the gloss layer a base layer comprising a thermoplastic polyolefin; and
forming a multi-layer structure.
6 . A thermoformed article comprising:
a gloss layer comprising a propylene-based polymer with a melt flow rate from about 0.1 g/10 min to about 1.5 g/10 min as measured in accordance with ASTM D-1238 2.16 kg, 230° C., the gloss layer having a pre-thermoformed Gardner gloss value greater than or equal to about 80 and a post-thermoformed Gardner gloss value greater than or equal to about 60 as measured in accordance with ASTM D-523 at 60°.
7 . The thermoformed article of claim 6 wherein the propylene-based polymer comprises greater than about 3.5 wt % units derived from ethylene and the gloss layer has a post-thermoformed Gardner gloss value greater than or equal to about 80.
8 . The thermoformed article of claim 6 wherein the propylene-based polymer comprises less than about 3.5 wt % units derived from ethylene and the gloss layer has a post-thermoformed Gardner gloss value from about 60 to about 70.
9 . The thermoformed article of claim 6 wherein the propylene-based polymer is a clarified propylene-based polymer.
10 . The thermoformed article of claim 6 wherein the propylene-based polymer is a coupled propylene-based polymer.
11 . The thermoformed article of claim 6 wherein the propylene-based polymer is a clarified coupled propylene-based polymer.
12 . The thermoformed article of claim 6 comprising a base layer comprising a thermoplastic polyolefin coextruded to the gloss layer.
13 . The thermoformed article of claim 12 wherein the base layer comprises a coupled impact propylene copolymer and an elastomer.
14 . The thermoformed article of claim 12 wherein the base layer comprises a blend of a propylene homopolymer, an elastomer, and a filler.
15 . A thermoformed article comprising:
a gloss layer comprising a propylene-based polymer comprising (i) greater than about 3.5 wt % units derived from ethylene and (ii) a melt flow rate from about 0.1 g/10 min to about 1.5 g/10 min as measured in accordance with ASTM D-1238 2.16 kg, 230° C., the layer having a post-thermoformed Gardner gloss value greater than or equal to about 80 as measured in accordance with ASTM D-523 at 60°.
16 . The thermoformed article of claim 15 wherein the propylene-based polymer comprises about 5 wt % to about 10 wt % units derived from ethylene.
17 . The thermoformed article of claim 15 wherein the propylene-based polymer is selected from the group consisting of a clarified propylene-based polymer, a coupled propylene-based polymer, and combinations thereof.
18 . The thermoformed article of any of claims 15 comprising a base layer coextruded to the gloss layer.
19 . The thermoformed article of claim 18 wherein the base layer comprises a coupled impact propylene copolymer and an elastomer.
20 . The thermoformed article of claim 18 wherein the base layer comprises a blend of a propylene homopolymer, an elastomer, and a filler.