Patent ID: 8540842
Filing Date: 2013-09-24
Classification: B23K,B29C,B29K,B32B,Y10T

Abstract:
1. A method for making a light weight composite comprising: (i) providing a roll of a first metallic layer, wherein the first metallic layer is a foil; (ii) providing a roll of a second metallic layer, wherein the second metallic layer is a foil; and (iii) providing at least one sheet of a polymeric core layer, the polymeric core layer including greater than 40 volume percent of a thermoplastic polymer, based on the total volume of the polymeric core layer, and from about 3 volume percent to 25 volume percent metal fibers based on the total volume of the polymeric core layer, wherein the metal fibers have an average length from 100 μm to 8 mm, and the thermoplastic polymer includes a polyethylene copolymer consisting of one or more α-olefins and optionally one or more additives wherein the thermoplastic polymer forms a polymeric matrix and the metal fibers are dispersed in the polymeric matrix: (iv) disposing the polymeric core layer between the first layer and the second layer; (v) heating the metallic layers to a temperature greater than about 90° C.; (vi) heating at least a portion of the polymeric core layer to a temperature greater than T (vii) applying a pressure to the metallic layers and the polymeric core layer so that a sandwich composite is formed, wherein the concentration of pores and voids in the polymeric core layer is from 0 to about 10 volume %, based on the total volume of the polymeric core layer; and (viii) cooling the composite material below the melting temperature of the thermoplastic polymer of the polymeric core layer; wherein the process is free of a step of heating the composite material to a temperature at which the metal fibers fuse together; wherein the polyethylene copolymer includes at least about 80 weight % ethylene, the volume ratio of the thermoplastic polymer to the metal fibers is greater than about 3:1, and the thermoplastic polymer has a number average molecular weight greater than about 20,000; wherein the thermoplastic polymer optionally further comprises a grafted polymer including a maleic anhydride grafted polyolefin, wherein the concentration of any grafted polymer in the polymeric core layer is up to about 10 wt %, based on the total weight of the polymeric core layer; and wherein the resulting composite material may be plastically deformed at strain rates greater than about 0,1 s