Method of producing a curved product comprising drawn polymer reinforcing elements and product obtained thereby

Abstract

The invention relates to a process for manufacturing a curved product, wherein the process comprises positioning a plurality of drawn polymeric reinforcing elements onto a mandrel, locally adhering at least a part of the elements to each other, and removing the product from the mandrel. The invention also relates to a process for manufacturing a curved article, preferably an armour article, from the curved product, the process comprising positioning the curved product in a mould and compressing said product at an elevated temperature and pressure. The curved armour article has good antiballistic properties and is substantially free of wrinkles.

1 . Process for manufacturing a curved product, wherein the process comprises positioning a plurality of drawn polymeric reinforcing elements onto a mandrel, locally adhering at least a part of the elements to each other, and removing the product from the mandrel. 
     
     
         2 . Process according to  claim 1 , wherein the step of locally adhering at least part of the elements to each other comprises locally bringing the drawn polymeric reinforcing elements to above their melting temperature and fusing them together. 
     
     
         3 . Process according to  claim 1 , wherein the step of locally adhering at least part of the elements to each other comprises locally applying a binder to the drawn polymeric reinforcing elements and solidifying the binder. 
     
     
         4 . Process according to  claim 1 , wherein the process further comprises providing the curved product with a polymer film layer, which layer has a lower melting point than the reinforcing elements. 
     
     
         5 . Process according to  claim 4 , wherein the curved product is enclosed in a polymer film envelope, in contact with the outer and/or inner surface of the product, to which envelope a vacuum is applied. 
     
     
         6 . Process according to  claim 1 , wherein the drawn polymeric reinforcing elements comprise fibers and/or films and/or tapes, having a strength of at least 1.6 GPa. 
     
     
         7 . Process according to  claim 6 , wherein the drawn polymeric reinforcing elements comprise fibers and/or films and/or tapes of ultrahigh molecular weight polyethylene. 
     
     
         8 . Process according to  claim 1 , wherein a plurality of reinforcing elements is simultaneously positioned onto the mandrel by supply means. 
     
     
         9 . Process according to  claim 8 , wherein the supply means control the tension of a reinforcing element between the mandrel surface and the supply means. 
     
     
         10 . Process according to  claim 1 , wherein part of the reinforcing elements is positioned in a pattern that is at least partly non-geodetic. 
     
     
         11 . Process for manufacturing a curved article, the process comprising positioning a curved product obtained by a process according to  claim 1 , in a mould and compressing said preform at an elevated temperature and pressure. 
     
     
         12 . Process according to  claim 11 , wherein the elevated temperature is chosen between the melting point of the reinforcing elements and 40° C. below the melting point. 
     
     
         13 . Process according to  claim 12 , wherein the elevated temperature is chosen between the melting point of the reinforcing elements and 20° C. below the melting point. 
     
     
         14 . Curved article, preferably a combat helmet or a radome, obtainable by a process according to  claim 11 .