Interlayer hot compaction
A process for the production of a polymeric article comprises: (a) forming a ply having successive layers, namely, (i) a first layer made up of strands of an oriented polymer material; (ii) a second layer of a polymeric material; (iii) a third layer made up of strands of an oriented polymeric material, wherein the second layer has a lower peak melting temperature that of the first and third layers; (b) subjecting the ply to conditions of time, temperature, and pressure sufficient to melt a proportion of the fits layer, to melt the second layer entirely, and to melt a proportion of the third layer, and to compact the ply; and (c) cooling the compacted ply. The resultant articles have good mechanical properties yet may be made at a lower compaction temperature than articles not employing the second layer, leading to a more controllable manufacturing process.
1. A polymeric article having a non-planar shape comprising a compacted ply including at least three layers that is adapted to be subjected to conditions of time, temperature and a single compaction temperature to melt at least 1% but no more than 30% by volume of first and third layers and substantially all of a second layer wherein the compacted ply is further configured to be subjected to a compaction pressure to form a non-planar article, wherein a thickness of the first and third layers individually exceed a thickness of the second layer, and wherein the first and third layers of ply comprise the same polymer and the second layer comprises a polymer with the same chemical composition and grade of polymers as the first and third layers with a lower degree of molecular orientation and lower peak melting temperature than that of the first and third layers.
2. The polymeric article of claim 1 wherein the first and third layers comprise polyethylene, polypropylene, polyoxymethylene, polyester, blends thereof, and mixtures thereof.
3. The polymeric article of claim 1 wherein the second layer has a melting temperature of at least 5° C. lower than the melting temperature of the first or third layers.
4. A polymeric article in a shape of a flat sheet comprising a compacted ply including at least three layers that is adapted to be subjected to conditions of time, temperature and a single compaction temperature to melt less than or equal to 30% by volume of first and third layers and substantially all of a second layer wherein the compacted ply is further configured to be subjected to a compaction pressure to form a non-planar article, wherein a thickness of the first and third layers individually exceed a thickness of the second layer, and wherein the first and third layers of ply comprise the same polymer and the second layer comprises a polymer with the same chemical composition and grade of polymers as the first and third layers with a lower degree of molecular orientation and lower peak melting temperature than that of the first and third layers.
5. The polymeric article of claim 4 wherein the first and third layers comprise polyethylene, polypropylene, polyoxymethylene, polyester, blends thereof, and mixtures thereof.
6. The polymeric article of claim 4 wherein the second layer has a melting temperature of at least 5° C. lower than the melting temperature of the first or third layers.
7. A polymeric article having a flat shape comprising a compacted ply including at least three layers that is adapted to be subjected to conditions of time, temperature and a single, compaction temperature to melt at least 1% but no more than 30% by volume of first and third layers and substantially all of a second layer wherein the compacted ply is further configured to be subjected to a compaction pressure to form a non-planar article, wherein a thickness of the first and third layers individually exceed a thickness of the second layer, and wherein the first and third layers of ply comprise the same polymer and the second layer comprises a polymer with the same chemical composition and grade of polymers as the first and third layers with a lower degree of molecular orientation and lower peak melting temperature than that of the first and third layers.
8. A polymeric article having a non-planar shape comprising a compacted ply including at least three layers that is adapted to be subjected to conditions of time, temperature and a single compaction temperature to melt not more than 30% by volume of first and third layers and substantially all of a second layer wherein the compacted ply is further configured to be subjected to a compaction pressure to form a non-planar article, wherein a thickness of the first and third layers individually exceed a thickness of the second layer, and wherein the first and third layers of ply comprise the same polymer and the second layer comprises a polymer with the same chemical composition and grade of polymers as the first and third layers with a lower degree of molecular orientation and lower peak melting temperature than that of the first and third layers.
9. The composition of claim 8 wherein a layer comprises a polymer selected from the group consisting of polyethylene, polypropylene, polyoxymethylene, polyester, blends thereof, and mixtures thereof.
10. The composition of claim 8 wherein a layer comprises a homopolymer, a copolymer, a terpolymer, a filled polymer, or mixtures thereof.
11. The polymeric article of claim 8 wherein the second layers has a melting temperature of at least 5° C. lower than the melting temperature of the first or third layers.